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Articles 2581 - 2610 of 3528
Full-Text Articles in Physical Sciences and Mathematics
Infrared Emission Spectroscopy Of Hot Carbon Monoxide, Farnood Khalilzadeh Rezaie
Infrared Emission Spectroscopy Of Hot Carbon Monoxide, Farnood Khalilzadeh Rezaie
Electronic Theses and Dissertations
Gas giant exoplanets known as hot Jupiters orbit close to their parent stars and are heated to high temperatures. Their infrared spectra, measured by photometry during secondary eclipses, are dominated by carbon monoxide and methane, the principle reservoirs of carbon on these planets. The relative CO and CH4 abundances inform us about temperature and pressure conditions and also about mixing by global winds driven by intense but asymmetric heating for these tidally locked bodies. Emission spectra collected during secondary eclipses, as the hot Jupiter passes behind its parent star, in principle allows a determination of the CO:CH4 concentration ratio. Since …
Perceptual Image Quality Of Launch Vehicle Imaging Telescopes, Joshua K. Lentz
Perceptual Image Quality Of Launch Vehicle Imaging Telescopes, Joshua K. Lentz
Electronic Theses and Dissertations
A large fleet (in the hundreds) of high quality telescopes are used for tracking and imaging of launch vehicles during ascent from Cape Canaveral Air Force Station and Kennedy Space Center. A maintenance tool has been development for use with these telescopes. The tool requires rankings of telescope condition in terms of the ability to generate useful imagery. It is thus a case of ranking telescope conditions on the basis of the perceptual image quality of their imagery. Perceptual image quality metrics that are well-correlated to observer opinions of image quality have been available for several decades. However, these are …
Fractal Spectral Measures In Two Dimensions, Beng Oscar Alrud
Fractal Spectral Measures In Two Dimensions, Beng Oscar Alrud
Electronic Theses and Dissertations
We study spectral properties for invariant measures associated to affine iterated function systems. We present various conditions under which the existence of a Hadamard pair implies the existence of a spectrum for the fractal measure. This solves a conjecture proposed by Dorin Dutkay and Palle Jorgensen, in several special cases in dimension 2.
Few-Cycle Pulses Amplification For Attosecond Science Applications Modeling And Experiments, Michael Hemmer
Few-Cycle Pulses Amplification For Attosecond Science Applications Modeling And Experiments, Michael Hemmer
Electronic Theses and Dissertations
The emergence of mode-locked oscillators providing pulses with durations as short as a few electric-field cycles in the near infra-red has paved the way toward electric-field sensitive physics experiments. In addition, the control of the relative phase between the carrier and the pulse envelope, developed in the early 2000’s and rewarded by a Nobel price in 2005, now provides unprecedented control over the pulse behaviour. The amplification of such pulses to the millijoule level has been an on-going task in a few world-class laboratories and has triggered the dawn of attoscience, the science of events happening on an attosecond timescale. …
Tunneling Conductance Characterization Of A Quantum Dot In The Fractional Quantum Hall Regime, Douglas E. Willard
Tunneling Conductance Characterization Of A Quantum Dot In The Fractional Quantum Hall Regime, Douglas E. Willard
Electronic Theses and Dissertations
This work represents a first-principles calculation of the electron tunneling current into quantum dots in the fractional quantum Hall effect regime. The system under consideration consists of an idealized Scanning Tunneling Microscope (STM) tip and a quantum dot with disk geometry and interacting electrons in a transverse magnetic field. Within the context of this model the tunneling current between the STM tip and the dot is examined for spin-polarized electrons at and around a filling factor of 1/3. The current expression is based on a second-quantized Hamiltonian in which electrons in the dot are interacting, confined, and restricted to the …
Innovative Pollutant Load Monitoring, Eric Gurr
Innovative Pollutant Load Monitoring, Eric Gurr
Electronic Theses and Dissertations
Modern streamflow measuring equipment, water quality sampling techniques and a better understanding of pollutant washoff are continuously being developed as today's society is in critical need of improving water management, minimizing developmental impacts and preventing environmental hazards. In particular, the study of the spatial, temporal and volumetric characteristics of annual pollutant loading caused by variations in precipitation, land use and other anthropogenic factors is of great significance due to their relation to future global water demands. The research presented here falls in three parts. In the first part of the dissertation, an acoustical Doppler velocity profiler installed in a submerged …
Ray Collection Bounding Volume Hierarchy, Kris Krishna Rivera
Ray Collection Bounding Volume Hierarchy, Kris Krishna Rivera
Electronic Theses and Dissertations
This thesis presents Ray Collection BVH, an improvement over a current day Ray Tracing acceleration structure to both build and perform the steps necessary to efficiently render dynamic scenes. Bounding Volume Hierarchy (BVH) is a commonly used acceleration structure, which aides in rendering complex scenes in 3D space using Ray Tracing by breaking the scene of triangles into a simple hierarchical structure. The algorithm this thesis explores was developed in an attempt at accelerating the process of both constructing this structure, and also using it to render these complex scenes more efficiently. The idea of using "ray collection" as a …
Techniques For Boosting The Performance In Content-Based Image Retrieval Systems, Ning Yu
Techniques For Boosting The Performance In Content-Based Image Retrieval Systems, Ning Yu
Electronic Theses and Dissertations
Content-Based Image Retrieval has been an active research area for decades. In a CBIR system, one or more images are used as query to search for similar images. The similarity is measured on the low level features, such as color, shape, edge, texture. First, each image is processed and visual features are extract. Therefore each image becomes a point in the feature space. Then, if two images are close to each other in the feature space, they are considered similar. That is, the k nearest neighbors are considered the most similar images to the query image. In this K-Nearest Neighbor …
Modeling Human Group Behavior In Virtual Worlds, Fahad Shah
Modeling Human Group Behavior In Virtual Worlds, Fahad Shah
Electronic Theses and Dissertations
Virtual worlds and massively-multiplayer online games are rich sources of information about large-scale teams and groups, offering the tantalizing possibility of harvesting data about group formation, social networks, and network evolution. They provide new outlets for human social interaction that differ from both face-to-face interactions and non-physically-embodied social networking tools such as Facebook and Twitter. We aim to study group dynamics in these virtual worlds by collecting and analyzing public conversational patterns of users grouped in close physical proximity. To do this, we created a set of tools for monitoring, partitioning, and analyzing unstructured conversations between changing groups of participants …
Effective Task Transfer Through Indirect Encoding, Phillip Verbancsics
Effective Task Transfer Through Indirect Encoding, Phillip Verbancsics
Electronic Theses and Dissertations
An important goal for machine learning is to transfer knowledge between tasks. For example, learning to play RoboCup Keepaway should contribute to learning the full game of RoboCup soccer. Often approaches to task transfer focus on transforming the original representation to fit the new task. Such representational transformations are necessary because the target task often requires new state information that was not included in the original representation. In RoboCup Keepaway, changing from the 3 vs. 2 variant of the task to 4 vs. 3 adds state information for each of the new players. In contrast, this dissertation explores the idea …
Characterization Of Intermolecular Pi-Type Interactions Using Sophisticated Quantum Mechanical, Electronic Structure Computations, Emily Joy Carrell
Characterization Of Intermolecular Pi-Type Interactions Using Sophisticated Quantum Mechanical, Electronic Structure Computations, Emily Joy Carrell
Electronic Theses and Dissertations
Much like the instrumentation in an experimental lab, computational chemists use computers to solve the mathematical equations that describe the physics of electrons to understand the chemistry involved. The combination of the two main components of computational chemistry, the basis set and method, determines the ``cost'' (disk, memory, and CPU time) of a computation. A variety of basis sets and methods have been developed in the past century. The focus of this report is to accurately describe non-covalent interactions with the use of various quantum computational techniques. In Chapter 1 a brief discussion on the theory behind computational chemistry is …
Asymptotics Of Carleman Polynomials For Level Curves Of The Inverse Of A Shifted Joukowsky Transformation, Michael Carr Northington
Asymptotics Of Carleman Polynomials For Level Curves Of The Inverse Of A Shifted Joukowsky Transformation, Michael Carr Northington
Electronic Theses and Dissertations
Let L be a level curve of the inverse of the shifted Joukowsky transformation w [special characters omitted] w − 1 + (w − 1) –1, that is, [special characters omitted]In this thesis we investigate the asymptotic properties of the sequence of polynomials that are orthonormal over the interior domain of L with respect to the area measure. We establish strong asymptotic formulas describing the behavior of these polynomials (as their degree increases) at every point of the complex plane.
Iteratively Reweighted Least Squares Minimization With Prior Information A New Approach, Dmitriy Popov
Iteratively Reweighted Least Squares Minimization With Prior Information A New Approach, Dmitriy Popov
Electronic Theses and Dissertations
Iteratively reweighted least squares (IRLS) algorithms provide an alternative to the more standard 1 l -minimization approach in compressive sensing. Daubechies et al. introduced a particularly stable version of an IRLS algorithm and rigorously proved its convergence in 2010. They did not, however, consider the case in which prior information on the support of the sparse domain of the solution is available. In 2009, Miosso et al. proposed an IRLS algorithm that makes use of this information to further reduce the number of measurements required to recover the solution with specified accuracy. Although Miosso et al. obtained a number of …
Prediction Of Survival Of Early Stages Lung Cancer Patients Based On Er Beta Cellular Expressions And Epidemiological Data, Evgeny Martinenko
Prediction Of Survival Of Early Stages Lung Cancer Patients Based On Er Beta Cellular Expressions And Epidemiological Data, Evgeny Martinenko
Electronic Theses and Dissertations
We attempted a mathematical model for expected prognosis of lung cancer patients based on a multivariate analysis of the values of ER-interacting proteins (ERbeta) and a membrane bound, glycosylated phosphoprotein MUC1), and patients clinical data recorded at the time of initial surgery. We demonstrate that, even with the limited sample size available to use, combination of clinical and biochemical data (in particular, associated with ERbeta and MUC1) allows to predict survival of lung cancer patients with about 80% accuracy while prediction on the basis of clinical data only gives about 70% accuracy. The present work can be viewed as a …
Zero Divisor Graphs And Poset Decomposition, Bette Catherine Putnam
Zero Divisor Graphs And Poset Decomposition, Bette Catherine Putnam
Electronic Theses and Dissertations
A graph is associated to any commutative ring R where the vertices are the non-zero zero divisors of R with two vertices adjacent if x · y = 0. The zero-divisor graph has also been studied for various algebraic stuctures such as semigroups and partially ordered sets. In this paper, we will discuss some known results on zero-divisor graphs of posets as well as the concept of compactness as it relates to zero-divisor graphs. We will dicuss equivalence class graphs defined on the elements of various algebraic structures and also the reduced graph defined on the vertices of a compact …
High Temperature And Pressure Resonant Ultrasound Spectroscopy Study Of Metal Hydride Systems, Rasheed Adebisi
High Temperature And Pressure Resonant Ultrasound Spectroscopy Study Of Metal Hydride Systems, Rasheed Adebisi
Electronic Theses and Dissertations
The goal of this dissertation is to characterize the elastic properties of palladium hydride near the tri-critical point as a classic example of metal hydride systems using the resonant ultrasound spectroscopy. A high temperature and high pressure resonant ultrasound spectroscopy system which include the RUS cell and the direct contact transducer set-up was designed and constructed. The temperature and pressure dependent of elastic moduli of palladium hydride and palladium crystals were obtained at five isotherms near the critical temperature, 293 °C and for pressure range of 250–500 psi. A strong softening of the shear modulus was observed at temperature and …
Comparing Media Coverage Of The Gulf Oil Spill In The Us And Uk Implications For Global Crisis Communication, Sarah Crytzer
Comparing Media Coverage Of The Gulf Oil Spill In The Us And Uk Implications For Global Crisis Communication, Sarah Crytzer
Electronic Theses and Dissertations
The following research is a content analysis of 114 articles written by the American and British news media outlets in the first month following the BP Gulf oil spill in April 2010. The goal of the research was to identify any dominant frames evident in the reports and to compare the two countries to see if there was a difference in the dominant frames used. Positive, negative, and neutral tones were also evaluated to determine if there was a difference between the countries. The results show that both countries reports predominantly used an ecology and action frame, while British media …
Two-Photon Cross Section Enhancement Of Photochromic Compounds For Use In 3d Optical Data Storage, Gheorghe Luchita
Two-Photon Cross Section Enhancement Of Photochromic Compounds For Use In 3d Optical Data Storage, Gheorghe Luchita
Electronic Theses and Dissertations
Rewritable photochrome-based 3D optical data storage requires photochromic molecules with high two-photon absorption (2PA) cross sections. Currently, the low value of two-photon absorption cross sections of existing photochromes makes them unsuitable for practical application in 3D data storage. Worldwide attempts to increase the cross section of photochromic molecules by altering the chemical structure have yielded poor results. In this work, two ways to increase the two-photon absorption cross sections of photochromes were investigated. In the first method, partial success demonstrated by extending the conjugation of a photochromic molecule, a high two-photon absorption cross section of the closed form isomer and …
Self-Assembly And Photophysics Of Selected Organic Materials And Two-Photon Bioimaging With Profluorescent Nitroxides, Polyelectrolyte Nanoparticles, And Squaraine Probes, Hyo Yang Ahn
Electronic Theses and Dissertations
Two-photon absorption and upconverted fluorescence has been utilized in a variety of applications in pure science and engineering. Multiphoton-based techniques were used in this research in order to understand photophysical and chemical characteristics of several fluorescent dyes and to demonstrate some of their key applications. Two-photon fluorescence microscopy (2PFM) has become a powerful technique in bio-photonics for non-invasive imaging in the near-infrared (NIR) region (700~1000 nm) that often results in less photobleaching. In Chapter 1, there is a brief introduction to fluorescence, examples of fluorescence materials, and a discussion of the advantages of two-photon absorption. 2PFM imaging was utilized in …
High Pressure And Micro-Spectroscopic Studies Of Single Living Erythrocytes And The Intraerythrocytic Multplication Cycle Of Plasmodium Falciparum, Silki Arora
Electronic Theses and Dissertations
A novel experimental approach for micro-absorption spectroscopy and high-pressure microscopy of single cells is developed and applied to the investigation of morphological, volume, and spectroscopic changes in healthy red blood cells (RBCs) and erythrocytes infected with the malaria parasite Plasmodium falciparum. Through real-time optical imaging of individual erythrocytes (size ~ 7[micrometer]) we determine the change in volume over the pressure range from 0.1 to 210 MPa. The lateral diameter of healthy RBCs decreases reversibly with pressure with an approximate slope of 0.015 [micrometer] / MPa. In infected cells, clear differences in the deformability and between the compression and decompression curves …
Characterization Of The Nonlinear Refractive Index Of Carbon Disulfide Over An Extended Spectral And Temporal Range, Marcus Seidel
Characterization Of The Nonlinear Refractive Index Of Carbon Disulfide Over An Extended Spectral And Temporal Range, Marcus Seidel
Electronic Theses and Dissertations
The intensity dependent refractive index change of a medium is frequently described in terms of the product n₂ · I where n₂ is the nonlinear refractive index and I the light intensity. The nonlinear refractive index is often treated as constant which is a reasonable assumption if the light interacts only with bound electrons. In the case of carbon disulfide (CS₂) however, nuclear motions contribute to n₂. These motions occur on the sub picosecond time scale and thus become especially relevant for ultrashort laser pulses. The neat liquid CS₂ is studied because it exhibits a large nonlinear refractive index in …
An Approach To Improve The Failure Rate Model Of A Solid State Laser By Utalizing The Physics Of Failure Methodology, Omar L. Thompson
An Approach To Improve The Failure Rate Model Of A Solid State Laser By Utalizing The Physics Of Failure Methodology, Omar L. Thompson
Electronic Theses and Dissertations
The ability to predict the failure rate of any military laser is very critical. In-field laser usage does not support the troubleshooting and repairing of a complex electro optical system. The only published laser failure rate model was last updated by the Department of Defense in 1975. Consequently, the failure rate predicted is inaccurate due to model deficiencies. This dissertation has developed a laser failure rate model for diode pumped lasers with improved failure rate prediction accuracy. The model has surpassed the capabilities of the Department of Defense model by the inclusion of key performance attributes that are currently not …
Investigation Of Nanoceria-Modified Platinum-Gold Composite Electrodes For The Electrochemical Reduction Of Oxygen In Alkaline Media, Rahul Hegishte
Investigation Of Nanoceria-Modified Platinum-Gold Composite Electrodes For The Electrochemical Reduction Of Oxygen In Alkaline Media, Rahul Hegishte
Electronic Theses and Dissertations
Platinum-gold and nanoceria-modified platinum-gold electrodes were prepared on a platinum surface via electrochemical reduction of solutions of platinum and gold salts in the dispersion of nanoceria. The molar ratios of Pt and Au were varied in both PtAu and PtAu/CeO₂ electrodes while the total concentration of the metals was maintained at 2 x 10⁻³M and the concentration of nanoceria was maintained constant at 5 x 10⁻³M. The electrodes were characterized by their cyclic voltammetry curves in 0.5M sulfuric acid solution. The electrochemically active area of the electrodes was determined using the copper underpotential deposition method. The linear sweep voltammograms of …
The Application Of Two-Photon Absorbing Probes In Lysosomal, Zinc Ion Sensing And Folate Receptor-Targeted Bioimaging, Xuhua Wang
Electronic Theses and Dissertations
Two-photon fluorescence microscopy (2PFM) has become a powerful technique for bioimaging in non-invasive cancer diagnosis and also investigating the mechanization and original of a variety of diseases by tracking various biological processes. Because the fluorescence emission by two photon absorbing (2PA) is directly proportional to the square of the intensity of excitation light, this intrinsic property of 2PA provides 2PFM great advantages over traditional one-photon fluorescence microscopy (1PFM), including high 3D spatial localization, less photodamage and interference from biological tissue because of using longer wavelength excitation (700-1300 nm). However, most 2PA probes are hydrophobic and their photostabilities are questionable, severely …
Low Noise And Low Repetition Rate Semiconductor-Based Mode-Locked Lasers, Dimitrios Mandridis
Low Noise And Low Repetition Rate Semiconductor-Based Mode-Locked Lasers, Dimitrios Mandridis
Electronic Theses and Dissertations
The topic of this dissertation is the development of low repetition rate and low noise semiconductor-based laser sources with a focus on linearly chirped pulse laser sources. In the past decade chirped optical pulses have found a plethora of applications such as photonic analogto-digital conversion, optical coherence tomography, laser ranging, etc. This dissertation analyzes the aforementioned applications of linearly chirped pulses and their technical requirements, as well as the performance of previously demonstrated chirped pulse laser sources. Moreover, the focus is shifted to a specific application of the linearly chirped pulses, timestretched photonic analog-to-digital conversion (TS ADC). The challenges of …
Metal Blacks As Scattering Centers To Increase The Efficiency Of Thin Film Solar Cells, Deep R. Panjwani
Metal Blacks As Scattering Centers To Increase The Efficiency Of Thin Film Solar Cells, Deep R. Panjwani
Electronic Theses and Dissertations
Metal nano particles are investigated as scattering centers on front surface of thin-film solar cells to improve efficiency. The principle is that scattering, which is enhanced near the plasmon resonance frequency of the particle and depends on particle size, increases the effective optical path length of incident light, leading to more light absorption in active layer of thin film solar cell. The particular types of particles investigated here are known as "metal-black", well known as an IR absorber for bolometric infrared detectors. Gold-black was deposited on commercial thin-film solar cells using a thermal evaporator in a nitrogen ambient at pressures …
Fine-Scale Structures In Saturn's Rings Waves, Wakes And Ghosts, Kevin Baille
Fine-Scale Structures In Saturn's Rings Waves, Wakes And Ghosts, Kevin Baille
Electronic Theses and Dissertations
The Cassini mission provided wonderful tools to explore Saturn, its satellites and its rings system. The UVIS instrument allowed stellar occultation observations of structures in the rings with the best resolution available (around 10 meters depending on geometry and navigation), bringing our understanding of the physics of the rings to the next level. In particular, we have been able to observe, dissect, model and test the interactions between the satellites and the rings. We first looked at kilometer-wide structures generated by resonances with satellites orbiting outside the main rings. The observation of structures in the C ring and their association …
The Relative Recoverability Of Dna And Rna Profiles From Forensically Relevant Body Fluid Stains, Charly Parker
The Relative Recoverability Of Dna And Rna Profiles From Forensically Relevant Body Fluid Stains, Charly Parker
Electronic Theses and Dissertations
Biological material (fluids or tissues) whether from the victim or suspect is often collected as forensic evidence, and methods to obtain and analyze the DNA found in that material have been well established. The type of body fluid (i.e. blood, saliva, semen, vaginal secretions, and menstrual blood) from which the DNA originated is also of interest, and messenger RNA typing provides a specific and sensitive means of body fluid identification. In order for mRNA profiling to be utilized in routine forensic casework, RNA of sufficient quantity and quality must be obtained from biological fluid stains and the methods used for …
Price Discovery In The U.S. Bond Market Trading Strategies And The Cost Of Liquidity, Haimei Shao
Price Discovery In The U.S. Bond Market Trading Strategies And The Cost Of Liquidity, Haimei Shao
Electronic Theses and Dissertations
The world bond market is nearly twice as large as the equity market. The goal of this dissertation is to study the dynamics of bond price. Among the liquidity risk, interest rate risk and default risk, this dissertation will focus on the liquidity risk and trading strategy. Under the mathematical frame of stochastic control, we model price setting in U.S. bond markets where dealers have multiple instruments to smooth inventory imbalances. The difficulty in obtaining the optimal trading strategy is that the optimal strategy and value function depend on each other, and the corresponding HJB equation is nonlinear. To solve …
Variational Embedded Solitons, And Traveling Wavetrains Generated By Generalized Hopf Bifurcations, In Some Nlpde Systems, Todd Blanton Smith
Variational Embedded Solitons, And Traveling Wavetrains Generated By Generalized Hopf Bifurcations, In Some Nlpde Systems, Todd Blanton Smith
Electronic Theses and Dissertations
In this Ph.D. thesis, we study regular and embedded solitons and generalized and degenerate Hopf bifurcations. These two areas of work are seperate and independent from each other. First, variational methods are employed to generate families of both regular and embedded solitary wave solutions for a generalized Pochhammer PDE and a generalized microstructure PDE that are currently of great interest. The technique for obtaining the embedded solitons incorporates several recent generalizations of the usual variational technique and is thus topical in itself. One unusual feature of the solitary waves derived here is that we are able to obtain them in …