Digital Commons Network^™

Absorbing State Transitions In Clean And Disordered Lattice Models, Man Young Lee

Doctoral Dissertations

"Nonequilibrium systems can undergo continuous phase transitions between different steady states. These transitions are characterized by collective fluctuations over large distances and long times similar to the behavior of equilibrium critical points. They also can be divided into different universality classes according to their critical behavior.

This dissertation considers two types of nonequilibrium transitions. First study concerns absorbing state transitions on a randomly diluted lattice. Second study deals with nonequilibrium models with several absorbing states. We investigate two specific nonequilibrium lattice models, i.e., the contact process and the generalized contact process by means of both theoretical and computational approaches.

In …

Aerogels And Films Through Free Radical Polymerization, Anand G. Sadekar

Doctoral Dissertations

"Aerogels are porous lightweight materials, unique among all solids in terms of low density, low thermal conductivity, low dielectric constants and high acoustic attenuation. The penalty for those exceptional properties is fragility. That issue has been addressed by bridging covalently (crosslinking) the elementary nanoscopic building blocks of silica aerogels with polymers. To streamline the crosslinking process we synthesized a bidentate free radical initiator (Si-AIBN) that gets attached on the skeletal nanoparticles and induces crosslinking by surface initiated polymerization (SIP). Here, we extend the scope of Si-AIBN in two directions: (a) we demonstrate extremely adhering, covalently attached polymer coatings on oxidized …

Assessing System Architectures: The Canonical Decomposition Fuzzy Comparative Methodology, Jason Paul Dauby

Doctoral Dissertations

"The impacts of decisions made during the selection of the system architecture propagate throughout the entire system lifecycle. The challenge for system architects is to perform a realistic assessment of an inherently ambiguous system concept. Subject matter expert interpretations, intuition, and heuristics are performed quickly and guide system development in the right overall direction, but these methods are subjective and unrepeatable. Traditional analytical assessments dismiss complexity in a system by assuming severability between system components and are intolerant of ambiguity. To be defensible, a suitable methodology must be repeatable, analytically rigorous, and yet tolerant of ambiguity. The hypothesis for this …

Probability Theory On Time Scales And Applications To Finance And Inequalities, Thomas Matthews

Doctoral Dissertations

"In this dissertation, the recently discovered concept of time scales is applied to probability theory, thus unifying discrete, continuous and many other cases. A short introduction to the theory of time scales is provided. Following this preliminary overview, the moment generating function is derived using a Laplace transformation on time scales. Various unifications of statements and new theorems in statistics are shown. Next, distributions on time scales are defined and their properties are studied. Most of the derived formulas and statements correspond exactly to those from discrete and continuous calculus and extend the applicability to many other cases. Some theorems …

Selective Laser Sintering Of 13-93 Bioactive Glass, Krishna C. R. Kolan

Masters Theses

"Bioactive glasses are promising materials for bone scaffolds due to their ability to assist in tissue regeneration. When implanted in vivo, bioactive glasses can convert to hydroxyapatite, the main mineral constituent of human bone and form a strong bond with the surrounding tissues, thus providing an advantage over polymer scaffold materials. Bone scaffold fabrication using additive manufacturing techniques like selective laser sintering (SLS) provide control over pore interconnectivity during the fabrication of scaffold, which helps in mimicking human trabecular bone. 13-93 glass, a third-generation bioactive material designed to accelerate the body's natural ability to heal itself, was used in …

Airline Revenue Management Using A Semi-Markov Critic Algorithm, Ketaki Dilip Kulkarni

Masters Theses

"This thesis presents a novel semi-Markov actor-critic algorithm to solve the airline revenue management (ARM) problem. The ARM problem has been the subject of much research since the deregulation of the airline industry in 1978. Various heuristics and numeric techniques have been developed and continue to be developed for solving this problem, but the search for more efficient techniques is still ongoing. This work focuses on the single-leg ARM problem modeled as a semi-Markov decision problem (SMDP). For Markov decision problems that suffer from the curses of dimensionality and modeling, it is difficult to obtain solutions with classical dynamic programming. …

Economic Evaluation Of Sustainable Strategies For The Transportation Sector, Yaqin Lin

Masters Theses

"Sustainable strategies are drawing growing attention as global environmental challenges increase concerns over energy consumption. As one of the most intensive consumers of energy, the transportation sector has a particular need to go green. Implementing alternative energy sources and applying advanced energy efficient technologies are two major approaches to achieve sustainability. Much work thus far used cost-effectiveness as an important criterion for assessing the practicability of sustainable strategies. However, few studies have evaluated such strategies systematically. This thesis has developed a framework of cost-effectiveness analysis to assess sustainability strategies. The framework summarizes the various effects of five representative alternative energy …

Fabrication Of Sers Active Nanostructures By Femtosecond Laser Micromachining, Matthew Aaron Olson

Masters Theses

"This work investigated the surface-enhanced Raman scattering (SERS) enhancement of gold nanoparticles on femtosecond laser created nanostructures on a silicon wafer. The goal was to use the nanostructures to assemble the nanoparticles into three-dimensional aggregates and compare these enhancements to those of two dimensional aggregates. The SERS enhancement generated by the three-dimensional structures was on average 5 x 10⁴ with a high enhancement of 1.2 x 10⁵. The magnitude of this enhancement was on par with previous experiments that tested SERS enhancements on gold nanoparticles, but it did not show any significant enhancement caused by the three-dimensional nature of the …

Exploring Join Caching In Programming Codes To Reduce Runtime Execution, Swetha Surapaneni

Masters Theses

"This thesis describes an approach to reduce the runtime of a large program by exploring object querying and query caching in programming codes. Some object-oriented languages allow the programmers to express queries explicitly in the code, which are optimized using the query optimization techniques from the database domain. In this regard, Java Query Language (JQL) has been developed that allows object querying and performs the query optimization and query caching at runtime. The problem that has been addressed in this thesis is how to reduce the runtime of a large program during the single execution by employing an efficient cache …

Improving Student Learning Outcomes Through Personal Response Systems (Clickers), Ran Cai

Masters Theses

"The main purpose of this research was to examine the impact of Personal Response Systems (PRS) or clickers, (as they are commonly called), on student learning outcome. Student learning outcomes as measured by course grades were compared between traditional lecture format and clicker use lecture format. Student perceptions on clicker use were observed in the mean time. Statistical analysis indicated that although student conveyed positive attitude on clicker adoption, there were no significant differences in course scores between students who used clickers and students who did not.

This study also considered the influence of other factors, such as gender, student …

Comprehensive Evaluation Of A Computer Based Learning System, Arun Sharma Chintalapati

Masters Theses

"This thesis presents the results of a comprehensive multi-method evaluation that was conducted on the Rapid Development System (RDS), a computer-based learning environment. The development of the project was funded by a National Science Foundation grant. Prior to this evaluation, the RDS had gone through two iterations.

A pre/post evaluation was conducted using questionnaires and eye tracking. Multi-method evaluation was employed to help triangulate the results and to provide additional insights. Data from the eye tracking was used to study the influence of the RDS interface on the attention and the cognitive workload of students with respect to the learning …

Laboratory Studies Of Compatibility Of Tamper Detection Materials With Improvised Explosive Device Crater Repairs, Levi Anthony Smith

Masters Theses

"Past methods for road repairs of craters caused by improvised explosive devices (IEDs) on main supply routes (MSRs) and alternative supply routes (ASRs) in Iraq and Afghanistan have been problematic. Traditional temporary and permanent solutions have proven deficient by being easily penetrable or by exposing troops for long periods of time. The use of a pre-blended rapid hardening cementitious material for lED crater repair has solved issues such as quick placement of the repair and high strength of the repair within an hour of placement. However, there are still issues with IEDs being hidden in repairs tampered by or replicated …

A Social Network Of Service Providers For Trust And Identity Management In The Cloud, Makarand Bhonsle

Masters Theses

"With the advent of a new paradigm in computing known as Cloud Computing which offers computing as a service, the inflow of a variety of service vendors is increasing constantly. One of the main challenges in this distributed network of service provisioning and deprovisioning system is the end user's privacy. Enforcing authentication and authorization protocols customized to the needs of every service provider evolves to a very intricate Identity Management System with respect to both the collaborating service providers as well as the user. This problem was addressed by the Federated Identity Management systems, where the user information is stored …

Memristor Based Lookup Table - Novel Testing And Reconfiguration Techniques, Veeresh Anilkumar Hongal

Masters Theses

"Nanotechnology is soon predicted to replace the CMOS technology, as current CMOS lithographic techniques will become void for complex IC designs with smaller feature size, and are hence incapable of keeping up with Moore's law. The devices in nanotechnology are fabricated using bottom up self-assembly. Memristor is one promising nanotech device which can replace the transistor used as a switch or memory device as it is just half the size and uses only fraction of the energy. This work considers Memristor Look Up Table (MLUT) design, which is a building block for asynchronous FPGAs built with memristors. In spite of …

Analyzing Dashboard Performance In Educational, Non-Profit Sectors, Rutuja B. Honnatti

Masters Theses

"Applications of the performance dashboard in the business sector are well documented, but very little research has been performed on its implementation in higher education. The changing economic scenario has exerted pressure on universities to perform to a new standard and achieve their missions and goals. The objective of this research is to investigate if performance management dashboards can be applied to overcome challenges faced by institutions of higher education, such as lack of access to information, stakeholders not taking advantage of what is being offered, students' anxiety about not being able to find a job and strategic planning. A …

Risk Assessment For Conceptual Design Of Hydrokinetic Turbines, Praveen Kailkere Srinivas

Masters Theses

"Hydrokinetic energy is a relatively new concept in the field of renewable energy. The rotor of the turbine, immersed in water, uses the velocity from the flowing water to generate power. Thus the hydrokinetic turbines are also known as zero head turbines. These turbines can be installed in rivers, oceans and sea beds. The design of these systems depends on the site conditions, installation and maintenance costs. Since this technology has not been assessed for its potential power producing capabilities, not much research has been done in order to harness this form of renewable energy and to study the impact …

Hilbert Transform Applications In Signal Analysis And Non-Parametric Identification Of Linear And Nonlinear Systems, Zuocai Wang

Doctoral Dissertations

"Hilbert Huang Transform faces several challenges in dealing with closely-spaced frequency components, short-time and weak disturbances, and interrelationships between two time-varying modes of nonlinear vibration due to its mixed mode problem associated with empirical mode decomposition (EMD). To address these challenges, analytical mode decomposition (AMD) based on Hilbert Transform is proposed and developed for an adaptive data analysis of both stationary and non-stationary responses. With a suite of predetermined bisecting frequencies, AMD can analytically extract the individual components of a structural response between any two bisecting frequencies and function like an adaptive bandpass filter that can deal with frequency-modulated responses …

Two-Point Bend Studies Of Glass Fibers, Zhongzhi Tang

Doctoral Dissertations

"The principal objective of this research is to advance our understanding of how glass breaks. Glass, a material well known for its brittleness, has been used widely but within a frustrating limit of its strength. Generally, strength is not considered as an intrinsic property of glass, due to the difficulty of avoiding the presence of flaws on the sample surface. The fiber drawing system and two-point bending (TPB) equipment developed at Missouri S&T allow the fabrication of pristine glass fibers and failure strain measurements while minimizing the effects of strength limiting critical flaws. Several conditions affect the failure behavior of …

Ozone And Terpene Reactions On Indoor Surfaces: Reaction Rates And Implications For Indoor Air Quality, Shi Shu

Doctoral Dissertations

No abstract provided.

Alloy Dissolution In Argon Stirred Steel, Darryl S. Webber

Doctoral Dissertations

"Alloying is required for the production of all steel products from small castings to large beams. Addition of large quantities of bulk alloys can result in alloy segregation and inconsistent alloy recovery. The objective of this research was to better understand alloy dissolution in liquid steel especially as it relates to Missouri S&Ts' patented continuous steelmaking process. A 45-kilogram capacity ladle with a single porous plug was used to evaluate the effect of four experimental factors on alloy dissolution: alloy species, alloy size or form, argon flow rate, and furnace tap temperature. Four alloys were tested experimentally including Class I …

Diesel Particulate Matter Dispersion Analysis In Underground Metal/Nonmetal Mines Using Computational Fluid Dynamics, Yi Zheng

Doctoral Dissertations

"Diesel Particulate Matter (DPM) is a natural by-product from operating diesel engines. Since diesel power is a major source of energy for mining operations today, the adverse health effects of DPM are of a great concern. To thoroughly resolve DPM problems, it is critical that DPM propagation characteristics be understood to arrive at a sensible and practical method for addressing DPM-related issues. To achieve this, a computational fluid dynamics (CFD) method is used to simulate DPM dispersion and to predict its concentration distribution. Industrial field studies were reconstructed to evaluate the possibility of different CFD models. Experiments were also carried …

Postcyclic Behavior Of Low-Plasticity Silt, Shuying Wang

Doctoral Dissertations

"Liquefaction of low-plasticity silt has been reported during earthquakes in the recent past. Excess pore pressure builds up due to the dynamic loading and then dissipates. The postcyclic behavior of low-plasticity silt was investigated in this research for materials obtained from the Mississippi River Valley. The experimental program involved specimen preparation using a slurry consolidation approach. A special technique was developed for specimen movement, reducing the testing program time by half. Both static and cyclic triaxial tests were conducted to confirm the ability to prepare replica specimens. In order to characterize the monotonic behavior, triaxial tests were conducted to determine …

Dynamic Ergonomic Analysis And Simulation Of Fastening Operation, Akul Joshi

Doctoral Dissertations

"Operator performing fastening operation with powered hand-tools at awkward postures is subjected to external forces that may pose a risk of developing ergonomic injuries. For design of safe workplaces and selection of tools it is necessary to identify the probable causes of discomfort by simulating the work conditions and quantifying the risk factors. An ergonomic simulator is developed to simulate the fastening operation and quantify the effects of posture and force in fastening operation. The effect of dynamic forces is analyzed using two approaches. The first approach analyzes the effect of tool vibration while the second analyzes the hand-arm system …

Leaching Characteristics Of Inorganic Contaminants From Coal Fly Ash, Tingzhi Su

Doctoral Dissertations

"Leaching of trace elements raises environmental concerns in coal fly ash disposal and reuse. US EPA is in the process of creating the first national rule on coal ash management. However, due to the complexity of coal fly ash composition, the leaching characteristics of trace elements are not well understood. Meanwhile, driven by the tightening emission regulations, new types of coal fly ashes are continuously generated as a result of the technological evolution at coal energy industry. The changing landscape highlights the needs for a comprehensive database to assess the leaching characteristics of different types of coal fly ashes, evaluation …

Preliminary Model Development Of Metal Complexation Of Polyester Derivatives Of 2,2'-Biimidazole, Shelonda Rena Taylor Finch

Doctoral Dissertations

"The objective of this study was to develop a chemical model for metal ion complex formation by a macroligand system with multi-metal binding sites using 2,2'-biimidazole as the starting molecule of the ligand system. Prior studies in this laboratory guided the selection of diesters and hydroxyethyl derivatives of 2,2'-biimidazole as model monomers. In addition, metal ion complexation studies with 2,2'-biimidazole derivatives were conducted. As a result, crystal structures of 1,1'-di(methylpropionato)-2,2-biimidazole, 2,2'-bis(1H-imidazolium) dinitrate and silver 2,2'-bis(1H-imidazolium) trinitrate, were reported. The crystal structures indicated a dependence upon the binding ability of the protonated 2,2'-biimidazole and counter ions. transesterification of the diesters and …

Quantum Phase Transitions In The Presence Of Disorder And Dissipation, Chetan Kotabage

Doctoral Dissertations

"A quantum phase transition is a phase transition at absolute zero occurring under variations in an external non-thermal parameter such as magnetic field or pressure. Quantum phase transitions are one among the important topics currently investigated in condensed matter physics. They are observed in various systems, e.g., in the ferromagnetic-paramagnetic phase transition in LiHoF₄ or in the superconductor-metal phase transition in nanowires.

A particular class of quantum phase transitions, which is phase transitions in the presence of disorder and dissipation, is investigated here. An example of this class is the ferromagnetic-paramagnetic phase transition in Ni₁₋ₓVₓ or CePd_1-xRhₓ caused …

Processing And Characterization Of Boron Carbide-Hafnium Diboride Ceramics, Harlan J. Brown-Shaklee

Doctoral Dissertations

"Hafnium diboride based ceramics are promising candidate materials for advanced aerospace and nuclear reactor components. The effectiveness of boron carbide and carbon as HfB₂ sintering additives was systematically evaluated. In the first stage of the research, boron carbide and carbon additives were found to improve the densification behavior of milled HfB₂ powder in part by removing oxides at the HfB₂ surface during processing. Boron carbide additives reduced the hot pressing temperature of HfB₂ by 150⁰C compared to carbon, which reduced the hot pressing temperature by ~50⁰C. Reduction of oxide impurities alone could not explain the difference in sintering enhancement, however, …

Workforce Planning Models For Semiconductor Manufacturing: Assembly-Test Operations, Shrikant Jarugumilli

Doctoral Dissertations

"We present a framework that integrates strategic and operational workforce planning models. Since these models provide decisions for planning horizons with different lengths, the formulation and solution strategy should ensure that the flow of information between these models is both appropriate and consistent.

The single-shift workforce planning problem is formulated as a two-phase goal program. In the first phase, the model allocates the workers to machine groups and identifies the shortage of workers (referred to as gap) followed by the second phase, in which certain constraints are relaxed and the workers are reallocated to the machine groups in order to …

Enhanced Heavy Oil Recovery By Alkali-Surfactant In The Pennsylvania Warner Sandstone, Rabia Mohamed Hunky

Doctoral Dissertations

"In this research, a study of the non-thermal method of alkaline-surfactant (AS) flooding to enhance heavy oil recovery from the Pennsylvanian Warner sandstone reservoir in Western Missouri was conducted. This work includ [sic] testing approximately 30 commercial surfactants and using a heavy oil sample with an API of 17. It was found that a number of surfactants could create stable emulsions. The viscosity of heavy oil could be reduced from 18,518 cp to 2.5 cp at 25⁰C through emulsification of certain surfactants. One of the major findings was that the emulsion created by the commercial surfactant, Igepalʼ CO-530 was stable …

Apparent Weekly And Daily Earthquake Periodicities In The Western United States, And Evolution Of Wadi Kubbania In Egypt, Ali Hadi Atef

Doctoral Dissertations

"The dissertation consists of two separate sections. The first section is on apparent daily and weekly periodicities in earthquake occurrence in the western United State [sic]. Analysis of Apparent Seismicity Rate (ASR) in the western United States confirmed the existence of prominent spectral peaks with a period of 1 and 7 days. The number of recorded earthquakes on Sundays for the duration of 1963-2008 is about 5% higher than that on weekdays, and, more significantly, there is a 9% increase of ASR in the early morning compared with that in the middle of the days. Significant similarities between the spatial …