Digital Commons Network^™

Performance And Results For Quartz Detector For The Superhms Spectrometer At Hall C Jefferson Lab, Jr. Benjamin Griego

Theses

A quartz detector has been constructed to be part of the trigger system for the Super High Momentum Spectrometer (SHMS). The SHMS will play a pivotal role in carrying out the 12-GeV physics program at Hall-C Jefferson Lab. The quartz hodoscope consists of twenty one fused silica bars. Each bar is 125 cm long, 5.5 cm wide, 2.5 cm thick, and is viewed by a UV-sensitive PMT on each end. The quartz hodoscope’s task is to provide a clean detection of charged particles, a high level of background suppression, and an accurate tracking efficiency determination. Initial test results of the …

3d Variational Analysis In Subsurface Contaminant Transport Model, Anup Saha

Theses

Modeling of contaminant transport in a subsurface environment by a numerical model deviates from the real world environment because of the highly heterogeneous nature of the subsurface environment. In this study, the data assimilation techniques are integrated with the numerical model and are applied to the subsurface environment to predict the contaminant transport. The Forward Time Center Space (FTCS) model is used as a numerical approach to solve the classical advection-dispersion-reaction transport equation and the Kalman Filter, Ensemble Kalman Filter (EnKF) and 3D Variational (3DVAR) analysis are used for data assimilation purpose. A hybrid scheme, termed as EnKF-3DVAR is developed …

Effect Of Material Ion Exchanges On The Mechanical Stiffness Properties And Shear Deformation Of Hydrated Cement Material Chemistry Structure C-S-H Jennite €“ A Computational Modeling Study, Babatunde Mattew Adebiyi

Theses

Material properties and performance are governed by material molecular chemistry structures and molecular level interactions. Methods to understand relationships between the material properties and performance and their correlation to the molecular level chemistry and morphology, and thus find ways of manipulating and adjusting matters at the atomistic level in order to improve material performance, are required. A computational material modeling methodology is investigated and demonstrated for a key cement hydrated component material chemistry structure of Calcium-Silicate-Hydrate (C-S-H) Jennite in this work. The effect of material ion exchanges on the mechanical stiffness properties and shear deformation behavior of hydrated cement material …

Measurement Of Optical Properties Of Soot Using Cavity Ring-Down Spectroscopy And Integrating Nephelometry, Damon M. Smith

Theses

Since black carbon and brown carbon are among the greatest contributors to radiative forcing (black carbon being second only to carbon dioxide), this work focuses on the laboratory measurement of their optical properties using cavity ring-down spectroscopy (CRDS) and integrating nephelometry. Water soluble soot is collected using an impinger and cascade impactor by burning different fuel types to mimic ambient aerosols dominant in regions where biomass burning is the main source of aerosols. Using an optical parametric oscillator (OPO) as a light source, we are able to measure extinction and scattering over a wide range of wavelengths. A correction factor …

Validation Study Of The Integral-Differential Scheme For Multi-Block Grids, Honest Frank Mrema

Theses

This MS Thesis seeks to validate the accuracy of the Integral-Differential Scheme (IDS). In the attempts to accomplish this task, research efforts were focused on the scheme's ability to capture the physics of known flow fields, as well as the scheme's ability to predict the features of flow field quantities that may be derived from experimental measurements. The IDS was developed with the goal of being computationally efficient, from a programming perspective, as well as being numerically accurate, stable, and robust, from a mathematical perspective. The IDS is designed to solve the full Navier-Stokes equations in their integral forms. Unlike …

Smart Polyacrylonitrile (Pan) Nanofibers With Thermal Energy Storage And Retrieval Functionality, De’Andre James Cherry

Theses

Phase change materials (PCMs) are generally substances with a high heat of fusion in the process of solid to liquid phase change. The nature of PCMs make them efficient materials to store and retrieve large amounts of thermal energy. Presently, high efficiency thermal energy storage/retrieval in applications where flexibility and space saving are required, such as smart textiles, still remains as a challenge. In this study, lauric acid (LA) and myristic acid (MA) were combined to prepare a specific binary fatty acid eutectic (LA-MA) with a melting point near the operating body temperature of a human being and then encapsulated …

Processing And Modeling Of Porous Copper Using Sintering Dissolution Process, Mustafa Abualgasim Salih

Theses

The growth of porous metal has produced materials with improved properties as compared to non-metals and solid metals. Porous metal can be classified as either open cell or closed cell. Open cell allows a fluid media to pass through it. Closed cell is made up of adjacent sealed pores with shared cell walls. Metal foams offer higher strength to weight ratios, increased impact energy absorption, and a greater tolerance to high temperatures and adverse environmental conditions when compared to bulk materials. Copper and its alloys are examples of these, well known for high strength and good mechanical, thermal and electrical …

A Model Approach To Flux-Pinning Properties Of Yba2cu3o7-δ Thin Film Vortex States Via Non-Superconducting Impurities, Jr Ronald Gamble

Theses

Thin film YBa2Cu3O7-δ (YBCO) samples with added non-superconducting nanodot defects of CeO2 and BaSnO2 are the focus of recent high-temperature superconductor studies. These nanodots allow magnetic flux ( ) to penetrate at these sites of the superconducting lattice, thus creating a magnetic flux vortex state. Examining the structure shows that these quantized magnetic flux vortices arrange themselves in a self-assembled lattice. The nanodots, with non-superconducting properties, serve to present structural properties to restrict motion of these vorticies under a pinning-force and to enhance the critical current density. A formulation of a new model for the system by a variation in …

Design And Implementation Of Millimeter Wave Frequency Multiplier In 65nm Rf Cmos Technology, Rediet Sebsebie

Theses

In this thesis, the design and implementation of frequency multipliers in 65nm CMOS was explored for millimeter wave oscillators and optimized to achieve higher output power and better rejection of the fundamental frequency. Several types of frequency multipliers are discussed. Transformers for AC-coupling used in the frequency multipliers were also explored. The design and optimization of the circuits was performed using Sonnet, Cadence, and ADS software tools. In this work the design of a frequency multiplier which takes in a 12.5GHz signal and outputs 100GHz at the output is achieved. Three transformers are used for three stages of a frequency …

Improved Weight Functions Of High-Order Weno Schemes, Lee R. Redfearn

Theses

It has been shown that the conventional 5th-order Weighted Essentially Non-Oscillatory (WENO) scheme of Jiang and Shu degenerates to third order at points where the first and higher order derivatives of the solution become equal to zero. Recently, Yamaleev and Carpenter proposed new weight functions which drastically improve the accuracy of high-order WENO-type schemes and provide the design order of accuracy for smooth solutions with any number of vanishing derivatives, if their tuning parameters satisfy consistency constraints. The truncation error analysis reveals that the accuracy of the flux reconstruction provided by the new weight functions can be increased near strong …

Mechanical Properties Of Neat Cement Paste: Investigation Of Correlation To Degree Of Hydration And Water-To-Cement Ratios, Sean J. Walker

Theses

The mechanical strength of cement paste is the property of the material that is most obviously required for structural use. The strength of mortar or concrete depends on the cohesion of the cement paste and its adhesion to the aggregate particles. Cement paste consists of two parts, cement and water. When water is added to cement, it reacts with the cement in what is known as the hydration process. The scope of this study is to determine the mechanical properties of hydrated cement paste with respect to the degree of hydration for different water-to-cement ratios, for developing a molecular macroscopic …

Efficiency Of Ensemble Square-Root Kalman Filter In 3d Subsurface Contaminant Transport Modeling, Torupallab Ghoshal

Theses

A three dimensional subsurface contaminant transport model with advection, dispersion and reaction has been developed to predict transport of a reactive continuous source pollutant. Numerical Forward-Time-Central-Space (FTCS) scheme has been used to solve the advection-dispersion-reaction transport model and Kalman Filter (KF), Ensemble Kalman Filter (EnKF) and Ensemble Square Root Kalman Filter (EnSRKF) schemes have been used for data assimilation purpose. EnKF and EnSRKF both use Monte Carlo simulation in Bayesian implementation to propagate state estimation. The key difference between EnKF and EnSRKF is that EnSRKF does not require perturbation of observation during analysis stage. In this study, contaminant concentration is …

Novel Gaas-Based Materials For Reconfigurable Electro-Modulated Lasers In Optical Interconnects, Jiri Thoma

Theses

With the rapid commercialization of personal computers and with the ever increasing desire for faster and larger data transfer, there is a strong need to increase network capacity. One solution is to replace standard metallic connections by optical fibers and full optical technologies. Although such technologies exist and are successfully employed in backbone connections, their complexities hinder a wider utilization toward end customers. Therefore, both manufacturing and operational costs are crucial. Integration of several optical components onto a single device chip is the key element. A simplified integration scheme bringing an additional cost reduction is also welcomed. This thesis presents …

Analysis Of Multi-Layered Beam Structures Using Spectral Finite Element Method, Ahmet Unal

Theses

Multi-layered elastic structures are widely used in engineering applications due to their high strength, fatigue resistance and their ability to be tailored to meet different design requirements. Although they provide many benefits compared to their metallic counterparts, they are also susceptible to damage. In most cases, the damage detection in a multi-layered structure is challenging due to its complex structure and construction (e.g. delamination). Lamb wave based structural health monitoring has been successfully implemented in metallic beam and plate structures. Damage location, amount and the extent can be determined by comparing baseline signatures of wave propagation in the structure. However, …

Observational Analysis Of The Interaction Between A Baroclinic Boundary And Supercell Storms On 27 April 2011, Adam Thomas Sherrer

Theses

A thermal boundary developed during the morning to early afternoon hours on 27 April as a result of rainfall evaporation and shading from reoccurring deep convection. This boundary propagated to the north during the late afternoon to evening hours. The presence of the boundary produced an area more conducive for the formation of strong violent tornadoes through several processes. These processes included the production of horizontally generated baroclinic vorticity, increased values in storm-relative helicity, and decreasing lifting condensation level heights. Five supercell storms formed near and/or propagated alongside this boundary. Supercells that interacted with this boundary typically produced significant tornadic …

Multipath Interference In A Target Track Radar, Dena Nesmith

Theses

This thesis investigates multipath interference effects in low-elevation angle tracking. At low elevations, multipath interference causes angle tracking errors and loss of track in the worst cases. For this study, a detailed angle tracker model uses a linear phased array antenna, monopulse processor, and servo track filter to produce an angle track on a constant speed, low-elevation target. Using this model, the angle tracking error is analyzed for multiple radar frequencies. As the frequency is increased, the error fluctuations become more rapid and degrade the angle track. Also, a combined range and angle tracker model was simulated that uses alpha-beta …

Three-Dimensional Modeling Of An Ideal Nozzle For Advanced Propulsion, Kevin Schillo

Theses

Advanced propulsion systems such as pulsed fission and fusion rockets hold the potential for opening up the solar system in ways few other propulsion technologies can. The University of Alabama in Huntsville is exploring one such concept in the form of pulsed z-pinch fusion propulsion. One of the technical hurdles to utilizing any pulsed fusion concept is the conversion from an isotropic expansion of a plasma into directed motion to produce thrust. This thesis investigates three dimensional modeling of pulsed nozzle performance in which the initial gas is a cylindrical gas column, emulating the initial conditions found in pulsed plasma …

Measurement Of The Group Velocity Dispersion Of Air Using A Femtosecond Comb, Reem Al Salamah

Theses

In this thesis, the Group Velocity Dispersion (GVD) of air has been measured by using a femtosecond frequency comb at 1.5 µm. By comparing the spectra from a balanced and unbalanced Mach - Zehnder interferometer, the need for vacuum tube is eliminated. The method employs the Fast Fourier Transform of both auto- and cross correlation to find the spectral and their differences. The GVD of air is then calculated from these spectral phase differences. With twenty-five independent measurements, the GVD of air was found to be 0.0120 fs²/mm, with a standard deviation of 0.0075 fs²/mm.

Simulation Of Sound Propagating Over Soft Surface Using The Equivalent Source Method, Daniel Teye Ocansey

Theses

Noise generated by large explosions at military bases causes discomfort to residents living in the vicinity, for up to 20km away. This noise explosion has strong low-frequency content and can travel over long distances. Most of the theoretical and experimental work that has been done to study and reduce this type of noise involved the use of barriers and sound proofing the residential houses. In this thesis, we consider the application of reducing the acoustic noise by shaping the landscape. The solution of this problem is difficult due to the semi-infinite domain, especially in the case of soft ground. To …

Design Of Feedback Control For Active Mass Dampers Of Excited Structures, Sara Leona Bowen

Theses

Annually, our world experiences thousands of seismic events that are the cause of hundreds of structural disasters and human fatalities. The objective of the presented research is to contribute to the world’s social, economic, and environmental needs by designing an optimized feedback control for active mass dampers (AMDs) by reducing oscillations. The optimal design will meet the required specifications and maintain a structure’s quasi-ideal, static position throughout a seismic event. The system’s equation of motion (EOM) is derived by using the Lagrangian Method and the free-body diagram. All the simulated and experimental responses of the AMD-1 system are obtained using …

Parameter Sensitivity Analysis For Co-Mediated Sickle Cell De-Polymerization, Yao Selom Messan

Theses

Sickle cell anemia is an abnormality that causes a deformation in the shape of the red blood cell that hinders the circulation of the red blood cell through the blood vessel. The deformation is caused by the association of monomers to each other to form polymers (polymerization). The oxygenation of the sickle cell may lead to the melting of polymers (depolymerization). Many studies have been conducted to understand the dynamics of depolymerization. This study focuses on the impact of various parameters over the output values in the system of de-polymerization. Both mathematical and statistical approaches for the sensitivity analysis of …

Adaptations Of Bacterial Flagella To Animal And Plant Hosts, Alshae’ R. Logan

Theses

Flagella have been studied for more than a hundred years, yet there remains a simple and powerful question about how to further make use of the recent wave of genomic data to find differences between flagellar genes across diverse bacterial strains. With the comparative power of bacterial genomic data, we propose that flagellar gene sequences may be used as genetic markers that indicate evolutionary adaptations of different bacteria for different hosts. We specifically proposed to identify and utilize genetic sequence differences that may diagnose for the presence of bacterial pathogens found to infect different hosts, specifically animal versus plant hosts. …

Data-Driven Implementation To Filter Fraudulent Medicaid Applications, Muhammad Nader Suleiman

Theses

There has been much work to improve IT systems for managing and maintaining health records. The U.S government is trying to integrate different types of health care data for providers and patients. Health care fraud detection research has focused on claims by providers, physicians, hospitals, and other medical service providers to detect fraudulent billing, abuse, and waste. Data-mining techniques have been used to detect patterns in health care fraud and reduce the amount of waste and abuse in the health care system. However, less attention has been paid to implementing a system to detect fraudulent applications, specifically for Medicaid. In …

Switched-Capacitor Voltage Doubler Design Using 0.5 Μm Technology, Hanfeng Wang

Theses

While integrated circuit (IC) power management has been an eternal topic for chip designers, inductor based DC-DC converters have been dominant in the field for years. However, because of the natures of inductors: large electro-magnetic interference, high coupling noise, and difficult silicon fabrication process, they are not favorable to on-chip solutions. Switched-capacitor (SC) DC-DC converters, which adopt capacitors for their energy storage components, have become increasingly popular among both the academia and the industry, because, apparently, they avoid the drawbacks of the inductor counterparts, and can be directly implemented on-chip without additional fabrication process.

In this paper, we will investigate …

Development Of An Automated Astronomical Data Reduction Pipeline, Adrian Collins

Theses

The topic of this thesis is the design, development and deployment of a photometric analysis suite. This includes all the steps necessary to convert a raw astronomical image into a final differential light curve which describes the changes in intensity of a selected target over a given time period.

This thesis discusses the development of a suite of tools with the explicit aim of improving the quality of terrestrial based photometric measurements. This suite includes an automated data reduction pipeline (RealPhot) and associated distributed computing system {QuickiSHver) which have been developed to process the larger volumes of data which are …

The Impact Of Adaptation Delays On Routing Protocols Formobile Ad-Hoc Networks (Manets), Yamin Al-Mousa

Theses

MANETs are coping with major challenges such as the lack of infrastructure and mobility which causes networks topology to change dynamically. Due to limited resources, nodes have to collaborate and rely packets on the behalf of neighbors to reach their destinations forming multi-hop paths. The selection and maintenance of multi-hop paths is a challenging task as their stability and availability depend on the mobility of participating nodes, where paths used a few moments earlier would be rendered invalid due to ever changing topology. The purpose of a routing protocol is to establish and select valid paths between communicating nodes and …

Grassmann Learning For Recognition And Classification, Sherif Azary

Theses

Computational performance associated with high-dimensional data is a common challenge for real-world classification and recognition systems. Subspace learning has received considerable attention as a means of finding an efficient low-dimensional representation that leads to better classification and efficient processing. A Grassmann manifold is a space that promotes smooth surfaces, where points represent subspaces and the relationship between points is defined by a mapping of an orthogonal matrix. Grassmann learning involves embedding high dimensional subspaces and kernelizing the embedding onto a projection space where distance computations can be effectively performed. In this dissertation, Grassmann learning and its benefits towards action classification …

Design For Implementation Of Image Processing Algorithms, Jamison D. Whitesell

Theses

Color image processing algorithms are first developed using a high-level mathematical modeling language. Current integrated development environments offer libraries of intrinsic functions, which on one hand enable faster development, but on the other hand hide the use of fundamental operations. The latter have to be detailed for an efficient hardware and/or software physical implementation. Based on the experience accumulated in the process of implementing a segmentation algorithm, this thesis outlines a design for implementation methodology comprised of a development flow and associated guidelines.

The methodology enables algorithm developers to iteratively optimize their algorithms while maintaining the level of image integrity …

Server-Based Desktop Virtualization, Anas Raqi Shabaitah

Theses

Virtualization can be accomplished at different layers in the computational stack and with different goals (servers, desktops, applications, storage and network). This research focuses on server-based desktop virtualization. According to the Gartner group, the main business drivers for adopting desktop virtualization are: application compatibility, business continuity, security and compliance, mobility and improved productivity [15]. Despite these business drivers, desktop virtualization has not been widely adopted. According to a survey conducted by Matrix42, only 5% of desktop computers are virtualized [37]. The research deals with the challenges preventing the wider adoption of server-based desktop virtualization while focusing on two of the …

The Irish Lean Experience - Origins, Development, Current Practice And Emerging Trends, Dermot Mccarthy

Theses

Lean applications are widespread in today’s business world. Lean started as the Toyota Production System, or World Class Manufacturing, and developed into Lean, as a consequence of the major Womack and Jones publication. The Machine that Changed the World, published in 1990. This dissertation examines the impact of Lean on Irish manufacturing generally, and then examines the impact of Lean on professional Industrial Engineering in Ireland. It looks at the implications for professional Industrial Engineers in a Lean environment. Then emergent developments in Lean and Industrial Engineering in Ireland are examined. This research specifically seeks to examine the question of …