Digital Commons Network^™

Evaluation Of Variable Speed Limits Using A Genetic Algorithm Approach To Calibrate A Vissim Model, Brian Joseph Schaefer

Masters Theses

"The variable speed limit (VSL) system has been adopted on more and more roadways across the globe as an engineering tool for controlling traffic flow, particularly during congestion situations. An important and fundamental question raised among traffic engineers is: Are the costs of installing and operating variable speed limits really justified? In order to answer this question, this thesis measures the effectiveness of the VSL system applying the VISSIM microscopic simulation model to a non-recurrent congestion situation. For the analysis, a section of interstate was modeled in VISSIM and calibrated so that the simulated results closely reproduce the observed data …

Microalgal Bioremediation Of Nutrients In Wastewater And Carbon Dioxide In Flue Gas, Anand Murali Narasimhan

Masters Theses

"Microalgae are potential biofuel feedstocks that can provide solutions to the twin challenges of energy security and environmental pollution. They have great potential for the removal of excess nitrogen and phosphorus from wastewater including the farm runoff. They can capture carbon dioxide in the flue gas from coal fired power plants thereby reducing greenhouse gas and also producing algal biomass, which can be converted into biofuel. In this study, the nutrient consumption of Scenedesmus algae was investigated in a batch culture and the biomass yield was determined. Algae were able to utilize carbon in the form of soluble carbonates which …

Application Of Life Cycle Assessment To Estimate Environmental Impacts Of Surface Coal Mining, Ofentse Ditsele

Masters Theses

"Coal plays an important role in meeting the energy needs of the World. Given its abundance and low cost, its use is bound to increase with the growing energy demand. Despite its importance, there are concerns over coal's environmental burdens. In order to extract and use coal in a sustainable manner, sustainability assessment has to be comprehensive. Life Cycle Assessment (LCA) provides systematic and quantifiable measures for assessing environmental burdens of products and processes. Extensive LCA work has been done on coal use, particularly in electricity generation, but, the coal mining stage has been neglected, for the most part. This …

Strategic Process Integration Of Energy And Environmental Systems In Wastewater Treatment Plants, Bharath Kumar Gangichetty

Masters Theses

"Green environmental practices are increasingly important in combating serious global energy and environmental issues. Most wastewater treatment facilities were built when energy costs were not a concern; however, an increasing demand for energy, changing climatic conditions, and constrained energy supplies have resulted in the need to apply more energy-conscious choices in the maintenance or upgrade of existing wastewater treatment facilities. A detailed analysis of the majority of water and wastewater treatment services shows that most facilities operate far below the efficiency levels needed for effective energy use. Failure to comply with regulated environmental standards is also a problem. Although standards …

Borate Based Bioactive Glass Scaffolds For Hard And Soft Tissue Engineering, Steven B. Jung

Doctoral Dissertations

"The main objectives of this dissertation were to evaluate bioactive borate glass scaffolds for hard and soft tissue applications and determine the potential toxicity of the borate glasses on the adjacent and systemic tissues. Porous randomly oriented fiber scaffolds composed of bioactive borate glass were implanted in subcutaneous soft tissue sites and in calvaria defects of laboratory rats and no signs of toxicity (necrotic tissue, increase in macrophages or other immune cells) were detected in any of the adjacent tissues (hard or soft). Systemic organs (kidney and liver) of laboratory rats implanted with bioactive borate scaffolds were analyzed for possible …

Enhanced Photorefractivity In A Polymeric Composite Photosensitized With Modified Carbon Nanotubes, Naveen Kumar Lingam

Masters Theses

"This work involves the photosensitization of photorefractive polymeric composites through the inclusion of multiwalled and singlewalled carbon nanotubes grafted to poly(N-vinyl carbazole). The photorefractive nature of the holograms gratings was established using two-beam-coupling, yielding two-beam-coupling gain coefficients approaching 80 cm⁻¹. Degenerate-four-wave-mixing experiments exhibited diffraction efficiencies as high as 60% as well as over-modulation voltages as low as ~ 40 V/µm. These notable figures of merit indicate that the grafting of the various carbon nanotubes to the poly(N-vinyl carbazole) polymer resulted in enhanced photorefractive performance. The mechanism responsible for this enhancement in photorefractive performance is investigated using a variety of experimental …

Contribution-Based Priority Assessment In A Web-Based Intelligent Argumentation Network For Collaborative Software Development, Maithili Satyavolu

Masters Theses

"Decision making is an important aspect of the collaborative software development process which usually involves complex process of conflict resolution. Stakeholders approach decision making process from multiple perspectives and their priorities play a vital role in it. The priority assessment methods used in the argumentation process so far are usually static. Priorities remain constant throughout the decision making process. In order to make the collaborative system more closely replicate real-world scenarios, this work incorporates dynamic priority assessment into a web-based collaborative system which is based on intelligent computational argumentation. It evaluates priorities dynamically for each cycle of decision process based …

Nonlinear Finite Element Formulation Of The Soil Structure Interaction Through Two Parameter Foundation Model, Taraka Ravi Shankar Mullapudi

Masters Theses

"The response of shallow and raft foundations is having a significant importance due to its complex behavior because of the semi-infinite soil media. Winkler's model is the simplest model to deal with the structure and soil. The Winkler model represents the foundation reaction as proportional to the soil displacement at a particular point, which results in the elasticity of the soil being the only parameter in consideration. But in reality the soil cohesiveness is having a significant contribution in soil structure interaction, and therefore the consideration of coupling effects of Winkler springs need to be accounted. Most of the existing …

Glass Fiber-Reinforced Polyurea Strengthening Of Reinforced Concrete, Courtney Elizabeth Greene

Masters Theses

"Wide varieties of concrete repair-retrofit and strengthening methods have been developed and are being widely implemented. In recent years, the need for such strengthening systems has become apparent with increasing demands on aging infrastructure. These strengthening systems need to be increasingly more adaptable, providing ease of construction as well as withstanding a variety of loading conditions and hazards. Exterior-applied fiber-reinforced polymer systems are increasingly being used to meet these demands. The research contained herein investigates the strengthening benefits and characteristics from a specific glass fiber-reinforced polyurea coating system applied externally to structures by means of spraying. This coating would allow …

Distributed Spatiotemporal Detection For Chemical And Biological Threats Using Human Immune Mechanisms, Yatin Bodas

Masters Theses

"Ubiquitous detection of chemical and biological (CB) threats in an urban environment using widely distributed, low-cost, broad-spectrum sensors carried by public or on vehicles is extremely desirable and pertinent for homeland security. These distributed sensors should interoperate autonomously and adaptively to meet stringent operational and detection performance requirements. This research explores the use of scalable detection methodology, inspired by the human immune mechanisms to meet these challenges. An adaptive spatiotemporal control mechanism is proposed to organize the detection behavior of spatially dispersed sensors using peer-to-peer communication so that a shorter response time, higher probability of detection and lower false alarm …

Performance Evaluation Of A Novel Diesel Fuel Air Separation And Filtration System For An Indirect Injection Diesel Engine, Michael Ray Hess

Masters Theses

"The objective of this research was to evaluate an air/fuel separation system known as a Fuel Preporator. The device's efficacy was determined by studying the effect of air entrainment on engine performance and fuel consumption of a General Motors 6.5 L naturally aspirated indirect injection (IDI) diesel engine. A test bed was developed to accommodate the test engine and test methods were adapted from federal regulations for steady-state engine testing (40 CFR 89 Subpart E). Cases of 0%, 5%, 10%, and 20% volumetric air entrainment were investigated for engine operation with and without the Fuel Preporator. Key measured engine performance …

Improvised Explosive Device Crater Repair For Enduring Route Remediation, Daniel Roman Kienitz

Doctoral Dissertations

"Recent road repairs performed on main supply routes (MSRs) and alternative supply routes (ASRs) in Iraq and Afghanistan revealed several deficiencies in current repair techniques. Temporary solutions such as aggregate backfill, asphalt, and traditional concrete repairs were unacceptable due to the ease of emplacement of additional improvised explosive devices (IEDs). In addition to the threat of IED placement, the threat from exposure of the repair teams to enemy attack during placement and curing was substantial. In order to address these problems, this project investigated rapid hardening materials for improvised explosive device crater repair. A laboratory test program along with performance …

Determining The R Values For 12 Inch Deep Z-Purlins And Girts With Through-Fastened Panels Under Suction Loading, Kaye Dee Wibbenmeyer

Masters Theses

"Designing purlins for roof systems attached to through-fastened panels has been a subject well researched in the past. The current design specification uses a simplified approach to the designing of these members where the fully braced moment capacity of such members is multiplied by a reduction factor, commonly referred to as the R-value. This value represents the point in between the fully braced and fully unbraced member behavior. However, the current AISI Specification, S100, only contains R-values for purlins and girts up to 11.5 inches in depth. Since manufacturers are now rolling sections up to 12 inches deep, two confirmatory …

Zinc Iron Phosphate Glasses For Enameling Applications, Sagnik Saha

Masters Theses

"New compositions of low temperature black glasses were developed that are suitable as frits for enameling soda-lime silicate (S-L-S) glass substrates. Zinc iron phosphate glasses are of interest for this application because they possess dilatometric low softening points (under 600ºC) and have coefficients of thermal expansion that are compatible with S-L-S glass (in the range 90-110x10⁻⁷/ºC). The development of compositions with excellent chemical durability, particularly in acidic conditions, is also desired. Compositional modification were made to the (Na₂O+K₂O)·ZnO·MnO·Fe₂O₃·P₂O₅ glass system using design of experiments. The compositional boundaries used in the design were based on earlier work at Missouri S&T. The …

Dependency Of Machinability In Gray Cast Iron On Nitride-Induced Age Strengthening, Jared Teague

Doctoral Dissertations

"Work of previous researchers has suggested that room temperature age strengthening in gray cast irons improves machinability. Verification and quantification of the machinability improvement is important to industry. Improved machinability will reduce overall manufacturing costs and reduce raw material consumption by decreasing the rate at which tools are replaced. Experimental work was performed to determine a connection between improved machinability in gray cast iron and changes in machining mechanics. An industrial tool wear study verified that age strengthening improved machinability by reducing tool wear to less than one-quarter of the unaged value. Laboratory tests on iron castings from the same …

Ground Penetrating Radar Investigations In Upper Kama Potash Mines, Oleg N. Kovin

Doctoral Dissertations

"An understanding of the structure and state of the rock mass surrounding underground openings in the potash mines is critically important for safe mining, planning the methods of extraction of an orebody, and preventing the influx of ground water. Continuous common offset ground penetrating radar (GPR) data were acquired in the potash mine operated by the Joint Stock Company (JSC) "Silvinit" (Russia) as part of an investigation of both pre-existing fractures exposed by mine workings and other anomalous geological structures. During the course of GPR investigation, the electrical properties of salt-bearing units were determined, site-specific data acquisition techniques and object-oriented …

Neural Mrac Based On Modified State Observer, Yang Yang

Masters Theses

"A new model reference adaptive control design method with guaranteed transient performance using neural networks is proposed in this thesis. With this method, stable tracking of a desired trajectory is realized for nonlinear system with uncertainty, and modified state observer structure is designed to enable desired transient performance with large adaptive gain and at the same time avoid high frequency oscillation. The neural network adaption rule is derived using Lyapunov theory, which guarantees stability of error dynamics and boundedness of neural network weights, and a soft switching sliding mode modification is added in order to adjust tracking error. The proposed …

Corrosion Resistance Of Enamel-Coated Steel Reinforcement For Concrete, Charles Robert Werner

Masters Theses

"Originally developed to enhance the bond between concrete and steel, reactive enamel coatings have shown great promise in protecting steel from corrosive environments. However, the corrosion resistance of the material has not yet been tested beyond 40 days. Moreover, when the material was tested, it was applied to smooth steel pins, not deformed steel bars which are commonly used in reinforced concrete structures. Therefore, this study focused on the corrosion resistance of three different enamel coatings, along with a standard epoxy coating, each of which were applied to both smooth and deformed steel bars and included both short-term and long-term …

Stability Of Streambanks Subjected To Highly Variable Streamflows: The Osage River Downstream Of Bagnell Dam, Kathryn Nicole Heinley

Masters Theses

"Streambank erosion of the Osage River downstream of Bagnell Dam is naturally-occurring; however, it may be significantly worsened due to releases made from the dam to generate hydropower. In this study, six typical outflow release patterns from Bagnell Dam were evaluated to determine their effects, if any, on the stability and the rate and amount of erosion of the banks of the Osage River.

The Bank Stability and Toe Erosion Model (BSTEM), version 5.2, was used to carry out the erosion and stability calculations. The model was validated by using data from another study and comparing the results from BSTEM …

Internet-Accessible Hot Cell With Gamma Spectroscopy At The Missouri University Of Science And Technology Research Nuclear Reactor, Edwin Grant

Masters Theses

A dual-chambered internet-accessible heavily shielded facility with pneumatic access to the University of Missouri Science and Technology (Missouri S&T) 200 kW Research Nuclear Reactor (MSTR) core has been built and is currently under low level irradiation testing. The facility allows distance users doing collaborative work with Missouri S&T researchers to manipulate and analyze neutron irradiated samples remotely. The system consists of two shielded compartments, one for multiple sample storage (up to 11 samples), and the other for isolated radiation measurements and spectroscopy. The second chamber has multiple detector ports, graded shielding, and has the capability to support gamma spectroscopy using …

Management Of A University Satellite Program With Focus On A Refrigerant-Based Propulsion System, Shawn W. Miller

Masters Theses

"The Missouri University of Science and Technology Satellite (M-SAT) design team has established a satellite program to develop a pair of satellites to perform an autonomous formation flight mission. The resulting configuration was assembled for the Air Force Research Lab University Nanosat Program. This document, written by the Program Manager and former member of the Propulsion subsystem, is a description of the management process used by the team to develop a satellite configuration. Included in the document is a discussion of team organization, techniques for managing a program, and lessons learned during the 2007 to 2008 timeframe. The managing techniques …

Impact Of Management Status, Gender, And Level Of Project Involvement On Corporate Governance In A Role-Based Enterprise Portal Environment, Daniel Augusto Pereira Brás Sequeira

Masters Theses

"The underlying objective of this research project is to investigate the impact of management status, gender, and level of project involvement on corporate governance in a role-based enterprise portal environment. This is achieved through a case study which included the development of a role-based enterprise portal site prototype assessed through surveys targeted at different stakeholders at the case company. Six hypotheses were formulated addressing the core research question. The outcomes of the hypotheses testing suggest employees' perceptions of role-based enterprise portal's effectiveness, usability, and corporate identity design are, in general, not influenced by the employees' management role, gender, and project …

Efficient Modular Arithmetic Units For Low Power Cryptographic Applications, Rajashekhar Reddy Modugu

Masters Theses

"The demand for high security in energy constrained devices such as mobiles and PDAs is growing rapidly. This leads to the need for efficient design of cryptographic algorithms which offer data integrity, authentication, non-repudiation and confidentiality of the encrypted data and communication channels. The public key cryptography is an ideal choice for data integrity, authentication and non-repudiation whereas the private key cryptography ensures the confidentiality of the data transmitted. The latter has an extremely high encryption speed but it has certain limitations which make it unsuitable for use in certain applications. Numerous public key cryptographic algorithms are available in the …

Analysis Of Eurycea Hybrid Zone In Eastern Missouri, Bonnie Jean Beasley

Masters Theses

"Evolutionary mechanisms are often difficult to observe in action because evolution generally works slowly over time. Hybrid zones provide a unique opportunity to observe many evolutionary processes, such as reinforcement, because of the rapid changes that tend to occur in these zones. Salamanders provide an ideal model for examining the rapid changes in populations that result from hybridization because many closely-related species lack reproductive barriers. In Missouri, a well-documented hybridization zone exists among the two subspecies Eurycea longicauda longicauda (long-tailed salamander) and E. L. melanopleura (dark-sided salamander). These salamanders inhabit caves, limestone creek beds, and abandoned mine shafts. A closely …

Doubly Fed Induction Generator With Integrated Energy Storage System For Smoothening Of Output Power, Nishant Swaraj Chouhan

Masters Theses

"Wind energy is one of the fastest growing renewable energies in the world today. However, integration of wind power into the power system network is still confronting many challenges. One of the main challenges is the suppression of wind power fluctuations. This thesis focuses on integration of wind power with energy storage to overcome the integration challenges. The first part of this thesis investigates the suitability of energy storage systems for transmission, distribution and wind farm applications. A review on the available energy storage systems is performed considering several criteria. Efforts are made to investigate solutions that meet all the …

Representation And Validation Of Domain And Range Restrictions In A Relational Database Driven Ontology Maintenance System, Patrick Garrett. Edgett

Masters Theses

"An ontology can be used to represent and organize the objects, properties, events, processes, and relations that embody an area of reality [1]. These knowledge bases may be created manually (by individuals or groups), and/or automatically using software tools, such as those developed for information retrieval and data mining. Recently, the National Science Foundation funded a large collaborative development project for the semi-automated construction of an ontology of amphibian anatomy (AmphibAnat [2]). To satisfy the extensive community curation requirements of that project, a generic, Web-based, multi-user, relational database ontology management system (RDBOM [3]) was constructed, based upon a novel theoretical …

Energy-Efficient Task-Scheduling And Networking Protocols For Secure Wireless Networks, Sandeep Kolli

Masters Theses

"The performance of wireless networks is dependent on a number of factors including the available energy, energy-efficiency, data processing delay, transmission delay, routing decisions, security overhead, etc. Traditionally, due to limited resources, nodes were tasked with only collecting measurements and sending them to a base station or central unit for processing. With increased capabilities of microprocessors the data processing is pushed more toward network and its more capable nodes. This thesis focuses to virtualize the processing resources of the entire network and dynamically distribute processing steps along the routing path while optimizing performance. Additionally, a new multi-key encryption (MKE) scheme …

Evaluation Of Alternative Methods For Surface Preparation And Deposition Of Cerium-Based Conversion Coatings On Aluminum Alloys, William J. Gammill

Masters Theses

"This thesis investigates alternative surface preparation and deposition methods for cerium-based conversion coatings (CeCC) on high strength aluminum alloys. Cerium-based conversion coatings are being investigated as a more environmentally friendly replacement for chromium-based conversion coatings. Currently, the alloys are immersed in strong alkaline and acidic solutions to prepare the aluminum surfaces for conversion coating, in which immersion may not be suitable for all situations. Alternatives to this method were investigated, including wipe application of solution, ultrasonic processing in deionized water, and abrasive blasting with alumina. AI 7075-T6 test panels were prepared using each of these methods and compared to a …

Experimental And Computational Investigations Of Hydrogen Safety, Dispersion And Combustion For Transportation Applications, Shravan K. Vudumu

Doctoral Dissertations

"Hydrogen is an energy carrier that can be produced from a variety of sources, offering one of the viable solutions to the increasing demands for clean and sustainable energy. Compared to the conventional fuels, hydrogen has distinct properties that need to be properly accounted for during its safer storage and delivery as well as more efficient and cleaner utilization. The broader objective of this study is to contribute to the scientific knowledge necessary to overcome key technical barriers to the widespread implementation of hydrogen in transportation applications. Specifically, lower flammability limit of hydrogen is first measured with an enhanced experimental …

A Study Of The Growth And Structure Of Chromium And Iron Oxide Films On Pd(001) Using X-Ray Photoelectron Diffraction And Low Energy Electron Diffraction, Tina Dhekial-Phukan

Doctoral Dissertations

"In this study, attempts were made to grow well-ordered chromium- and iron-oxide films on a Pd(001) surface, and two sample preparation techniques, the multilayer and the sequential growth techniques, were used to grow these transition metal oxide films. The study is a part of a larger project that aims to look into the interaction between metal substrates and the overlayers grown on them. Previous studies of oxide films on Ag(001) resulted in the growth of 4-fold and 3-fold symmetry oxide structures from the multilayer and sequential growth techniques respectively. The present investigation's goal was to study how the growth of …