Engineering Commons^™

Modeling Contaminant Behavior In Lake Superior : A Comparison Of Pcbs, Pbdes, And Mercury , Mark D. Rowe

Dissertations, Master's Theses and Master's Reports - Open

A mass‐balance model for Lake Superior was applied to polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and mercury to determine the major routes of entry and the major mechanisms of loss from this ecosystem as well as the time required for each contaminant class to approach steady state. A two‐box model (water column, surface sediments) incorporating seasonally adjusted environmental parameters was used. Both numerical (forward Euler) and analytical solutions were employed and compared. For validation, the model was compared with current and historical concentrations and fluxes in the lake and sediments. Results for PCBs were similar to prior work showing …

Community Managed Rural Water Supply Systems In The Dominican Republic : Assessment Of Sustainability Of Systems Built By The National Institute Of Potable Water And Peace Corps, Dominican Republic , Ryan W. Schweitzer

Dissertations, Master's Theses and Master's Reports - Open

In the Dominican Republic economic growth in the past twenty years has not yielded sufficient improvement in access to drinking water services, especially in rural areas where 1.5 million people do not have access to an improved water source (WHO, 2006). Worldwide, strategic development planning in the rural water sector has focused on participatory processes and the use of demand filters to ensure that service levels match community commitment to post-project operation and maintenance. However studies have concluded that an alarmingly high percentage of drinking water systems (20-50%) do not provide service at the design levels and/or fail altogether (up …

Decentralized Or Centralized Production : Impacts To The Environment, Industry, And The Economy, Abigail R. Clarke-Sather

Dissertations, Master's Theses and Master's Reports - Open

Since product take-back is mandated in Europe, and has effects for producers worldwide including the U.S., designing efficient forward and reverse supply chain networks is becoming essential for business viability. Centralizing production facilities may reduce costs but perhaps not environmental impacts. Decentralizing a supply chain may reduce transportation environmental impacts but increase capital costs. Facility location strategies of centralization or decentralization are tested for companies with supply chains that both take back and manufacture products.

Decentralized and centralized production systems have different effects on the environment, industry and the economy. Decentralized production systems cluster suppliers within the geographical market region …

An Investigation On The Mixing Hydrodynamics Of A Gas-Solid Fluidized Bed, Mario Alberto Ruvalcaba

Open Access Theses & Dissertations

In previous decades, the experimental and numerical studies of multiphase flows have remarkably increased especially gas-solid flows. Research of this type has abundant applications in energy, chemical processes, among others. Moreover, common applications include fluid catalytic cracking for petroleum refineries, fluidized bed reactors (type of chemical reactors), interface modification, such as applying a coating onto solid items, and an important technology breakthrough in coal gasification. The work presented on this thesis concentrates on the investigation of gas-solid flows utilizing Computational Fluid Dynamics (CFD) methods. The gas-solid flows studies performed on this investigation assumed the solid phase as a continuum with …

Hydrogen Infrastructure: Resource Evaluation And Capacity Modeling, Kevin B. Martin

Doctoral Dissertations

"A hydrogen economy could offer energy stability, economical, and environmental benefits. Several issues are involved in the design and implementation of a hydrogen economy such as the selection of feedstocks, generation and storage technologies, transportation methods, appropriate equipment capacity, codes/standards and public awareness. The design of a hydrogen infrastructure may seem insurmountable; however, as the system is deconstructed a proper design can be achieved. In order to better understand how a hydrogen system for light duty vehicles might operate, both hydrogen resource and capacity analysis and modeling is conducted. Specifically, an evaluation of leading near term production and distribution technologies …

Automatic Detection Of White Areas In Dermoscopy Images, Ankur Dilip Dalal

Masters Theses

"This thesis presents an algorithm for automatically segmenting the white areas in dermoscopy images. The algorithm includes preprocessing of images, plotting the histogram (RGB) and calculating the average and standard deviation values (RGB) of the lesion. A threshold value for each color plane is determined using these parameters and white areas are automatically segmented. Various image features such as decile percentages and globule features are extracted and given to a neural network. The proposed algorithm has produced a maximum diagnostic accuracy of 94.67% and, when the lesions which touch the image border are removed from the set, the diagnostic accuracy …

Friction Stir Processing Of Laser Metal Deposited Ti-6al-4v, Romy Francis

Masters Theses

"Laser metal deposition (LMD) can form near net shaped components for aerospace applications. Ti-6Al-4V is a widely used aerospace alloy and fabrication of this alloy using LMD is gaining popularity. Improved mechanical properties are always a requirement in aerospace alloys and research is constantly being conducted to improve the properties of components formed from this alloy. Friction Stir Processing (FSP) in the past has been used as a method to change the surface properties of materials through microstructural modifications. The changes in properties can include hardness, corrosion resistance, fatigue strength, etc. The first section of this thesis is based on …

Zigbee-Enabled Structural Health Monitoring Using The Smartbrick System, Tyler Harms

Masters Theses

"This thesis describes the design, testing, and proposed extended field test of a wireless sensor network based on the SmartBrick, a structural health monitoring (SHM) device developed at Missouri S&T. The SmartBrick serves as the base station for the network, which utilizes additional sensor nodes to monitor the structure. Each node measures a range of environmental and structural phenomena, including vibration, tilt, humidity, and strain. The nodes use Zigbee short-range communication to transmit their data to the base station, which in turn uses the GSM cellular network to provide long-range communication capability and support for remote control.

Unlike many SHM …

Modeling Of Wear And Oxidation Behavior Of A Carbon/Carbon Multidisk Clutch, Shankar Nagaraj

Masters Theses

"Carbon/carbon composites are a family of advanced composite materials. They are the most advanced form of carbon and consist of a fiber, based on carbon precursors, embedded in a carbon matrix. They are extensively used in design of sliding contact systems such as clutches and brakes because of their low weight, excellent thermal and mechanical properties, chemical inertness and self lubricating capability. They retain their mechanical strength in inert atmospheres up to 2000° C. However, in oxidizing environments, C/C composites rapidly react with oxygen forming gaseous carbon oxides around 450° C.

In the present study a C/C composite clutch assembly …

Analysis Of Lesion Border Segmentation Using Watershed Algorithm, Hanzheng Wang

Masters Theses

"Automatic lesion segmentation is an important part of computer-based skin cancer detection. A watershed algorithm was introduced and tested on benign and melanoma images. The average of three dermatologists' manually drawn borders was compared as the benchmark. Hair removing, black border removing and vignette removing methods were introduced in preprocessing steps. A new lesion ratio estimate was added to the merging method, which was determined by the outer bounding box ratio. In postprocessing, small blob removing and border smoothing using a peninsula removing method as well as a second order B-Spline smoothing method were included. A novel threshold was developed …

Maximum Likelihood Fusion For Detection Of Led Precursors Using Laser-Induced Breakdown Spectroscopy, Pratik Shah

Masters Theses

"Improvised Explosive Devices (IEDs) pose an increasing threat to the safety of soldiers and civilians in embattled areas. The use of compounds such as RDX complicates the detection of IEDs, as these compounds are often hard to identify in the presence of contaminants such as alcohol, oils and dust. Spectroscopic techniques such as Laser-Induced Breakdown Spectroscopy (LIBS) and Raman have shown promise for the detection of explosive compounds; however, their accuracy is limited, as noise can cause variations in the peak strengths and locations that they utilize for classification.

The research presented in this thesis applies signal processing to the …

An Integrated Damping And Strengthening Strategy For Performance-Based Seismic Design And Retrofit Of Highway Bridges, Kazi Rezaul Karim

Masters Theses

"In this study, a damping-enhanced strengthening (DES) strategy was introduced to retrofit bridge structures for multiple performance objectives. The main objectives of this study are (1) to numerically demonstrate the effectiveness of the anchoring mechanism of a constrained damping layer in the proposed DES system, and (2) to evaluate the performances of a highway bridge retrofitted with a DES retrofit technique of viscoelastic (VE) damping and carbon-fiber-reinforced-polymer (CFRP) strengthening components that are nearly independent under weak earthquakes but strongly coupled under strong earthquakes"--Abstract, page v.

Development Of An Electronic Governor System For A Small Spark Ignition Engine, Donald Ray Hibler

Masters Theses

"The use of electronic controls on engines has been widespread and has now reached the small utility engine. The evolution from carburetion to electronic fuel injection has presented opportunity to implement additional controls with the intent to improve engine control and performance. In this study, an electronic governor system is developed for use on a small twin cylinder utility engine. This system is to replace an existing mechanical governor system, and it should have the potential as a production based solution that integrates with an existing fuel injection system. It must improve the speed droop characteristics over the current mechanical …

Vehicle Positioning Using Image Processing, Armadeep Kaur

Masters Theses

"An imaging-processing approach is described that detects the position of a vehicle on a bridge or similar environment. A load-bearing vehicle must be carefully positioned on a bridge for quantitative bridge monitoring. The personnel required for setup and testing and the time required for bridge closure or traffic control are important management and cost considerations. Consequently, bridge monitoring and inspections are good candidates for smart embedded systems. The objectives of this work are to reduce the need for personnel time and to minimize the time for bridge closure. An approach is proposed that uses a passive target on the bridge …

A Renewable Energy Feasibility Study To Power A Water Supply Pump In Sacala Las Lomas, Guatemala, William Anthony Granich

Masters Theses

"A clean and sufficient source of drinking water can be a challenge to develop in the rural highlands of Guatemala. Installing a submersible pump in a groundwater well can provide a source of water that is free of contamination and yields sufficient water throughout the year. Submersible pumps are typically powered from grid-power; however, an alternative energy source may be considered. An evaluation of the renewable energy resources has been conducted in Sacala las Lomas de San Martin Jilotepeque, Chimaltenango, Guatemala (Sacala). The drilling of a deep groundwater well has been proposed in Sacala to supply the community with sufficient, …

Time-Weighted Average Solid-Phase Microextraction (Twa-Spme) For In-Planta Detection Of Chlorinated Solvents, Emily Moore Sheehan

Masters Theses

"Recent interest in the use of phyto-mapping for plume delineation at contaminated sites has promoted a need for new and innovative sampling techniques. Solid-phase micro-extraction (SPME) methods have been developed as a chemical analysis tool offering fast, simple, non-invasive sampling without the use of solvents. In this study SPME devices were tested for applicability for in-planta detection of chlorinated solvents. To evaluate the use of SPME for VOCs in-planta a number of integrated studies were undertaken. Uptake profiles were developed for nine chlorinated solvents in a liquid polydimethylsiloxane (PDMS) matrix with 100 µm Carboxene SPME fibers. Timeweighted average (TWA) sampling …

The Assessment Of Winding Forces Due To Inrush Current In Large Transformers With Heavily Saturated Cores, Richard Howard Palmer

Masters Theses

"It has been suspected that certain high voltage generator step-up transformers due to large inrush current occurring when the transformers were connected to the energized transmission lines but the generators were not operating. Even though the transformers are designed to withstand the winding forces developed under short circuit conditions, the transformers failed when energized. Therefore, to gain further insight into this phenomenon, this research was undertaken. The research evaluates and compares the relative magnitude of the winding forces produced under inrush and short circuit current conditions in transformers of different design and winding configurations"--Abstract, page iv.

A Mobile Water Disinfection Unit Powered By Renewable Energy Systems, Matthew Vitello

Masters Theses

"The current method of disinfection of water used by the United States Army requires a significant amount of mobilization and demobilization time as well as being energy intensive. In an effort to improve small unit mobility a need for a light-weight, low maintenance, highly mobile disinfection system has arisen. In addition to the potential military use, a system of this type could provide a safe drinking water product during the aftermath of natural or man-made disasters, reducing the burden on emergency management services. A prototype system was developed that is self-powered, has low maintenance requirements, and can be stored for …

Depth Evaluation Of Damage To Aircraft Fuselage Skins Using Microwave And Millimeter Wave Methods, Andrew Dale Mcclanahan

Masters Theses

"The depth of damage to metal surfaces is a particularly useful, sought after, and difficult to obtain piece of information, and is used to guide repair decisions. For this investigation such damage is represented as rectangular slots (cracks) or cylindrical pits. Several millimeter wave methods are presented to evaluate depth. The quarter-wavelength resonant response of cracks, excited by a probing rectangular waveguide, allows evaluation of depth using the phase of reflection coefficient. A theoretical derivation is also supplied, modeling the system as the junction of two rectangular waveguides, the probing waveguide and the crack. If the crack is filled with …

Applications Of Swarm, Evolutionary And Quantum Algorithms In System Identification And Digital Filter Design, Bipul Luitel

Masters Theses

"The thesis focuses on the application of computational intelligence (CI) techniques for two problems - system identification and digital filter design. In system identification, different case studies have been carried out with equal or reduced number of orders as the original system and also in identifying a blackbox model. Lowpass, Highpass, Bandpass and Bandstop FIR and Lowpass IIR filters have been designed using three algorithms using two different fitness functions. Particle Swarm Optimization (PSO), Differential Evolution based PSO (DEPSO) and PSO with Quantum Infusion (PSO-QI) algorithms have been applied in this work"--Abstract, page iii.

Hydrogen Applications For Lambert - St. Louis International Airport, Mathew Thomas

Masters Theses

"Today, major airports are facing challenges related to pollution, energy efficiency, and safety and security. Hydrogen and fuel cell technologies, regarded as one of the key energy solutions of the 21st century are more energy efficient and reliable than conventional systems and have the potential to diminish these challenges. These technologies can also play a significant role in reducing the noise, air, and water pollution and enhancing energy security. This paper presents the design of a set of hydrogen technologies and systems that are commercially available and are ready for practical, real-world use. The hydrogen applications selected for Lambert-St. Louis …

Functional Testing Of Faults In Asynchronous Crossbar Architecture, Sriram Venkateswaran

Masters Theses

"The challenge of extending Moore's Law past the physical limits of the present semiconductor technology calls for novel innovations. Several novel nanotechnologies are being proposed as an alternative to their CMOS counterparts, with nanowire crossbar being one of the most promising paradigms. Quite recently, a new promising clock-free architecture, called the Asynchronous Crossbar Architecture has been proposed to enhance the manufacturability and to improve the robustness of digital circuits by removing various timing related failure modes. Even though the proposed clock-free architecture offers several merits, it is not free from the high defect rates induced due to nondeterministic nanoscale assembly. …

Classification Of Fine Particles Using A Taylor-Couette Device, Navina Durgaiah Tungapindi

Masters Theses

"The study of fine particle classification is common, especially since a well defined particle size distribution is important in most processes and products. Many methods have been developed to classify micron-size particles, and although each has its own advantage, most cannot classify particles to an extremely narrow range. This is partly due to the cohesive nature of fine particles, which can be due to electrostatic attraction, moisture, or van der Waals forces. In order to overcome this problem, a wet method of classification has been chosen here. Taylor vortices, discovered in 1923, develop in the fluid contained in the annulus …

Experiments And Modeling Of Shear-Driven Film Separation, J. L. Wegener

Masters Theses

"Dynamic thin liquid films driven by an adjacent gas flow have been subject to many investigations due to the presence of such films in many engineering applications. More specifically though, the behavior of such films at a sharply expanding corner has received little attention, but can be observed in internal combustion engines, liquid atomizer systems, refrigerant flows in evaporators, and film drag over wetted surfaces. Efforts to validate computational models of the propagation and separation of films are limited by the lack of reliable non-intrusive techniques to measure and analyze dynamic film parameters. In this study, film propagation models and …

Automatic Vessel And Telangiectases Analysis In Dermoscopy Skin Lesion Images, Beibei Cheng

Masters Theses

"The blood vessels are part of the circulatory system and function to transport blood throughout the body. Vessels have their own features such as distinctive color compared to surrounding skin as well as distinctive curved and/or linear shape. Telangiectases are small dilated blood vessels near the surface of the skin or mucous membranes, measuring between 0.5 and 1 millimeter in diameter. In this research, image analysis techniques are investigated to detect vessels in dermoscopy skin lesion images. Machine vision and neural network methods are explored to discriminate skin lesions containing telangiectases from those containing normal vessels. A vessels Detection technique …

Fatigue Of Friction Stir Welded Lap Joints With Sealants, Kenneth Doering

Masters Theses

"A lack of understanding of corrosion fatigue in friction stir welded aluminum joints prevents friction stir welding from being implemented in aerospace applications. Fatigue testing reveals a 60-75% reduction in the fatigue life of friction stir welded aluminum lap joints immersed in 3.5% NaCl solution (corrosion fatigue) compared with that of lap joints tested in ambient air. The loss in fatigue life is attributed to accelerated fatigue cracking due to hydrogen environment embrittlement. Two polymer sealant candidates are investigated: silicone rubber and nylon-11. Both sealant candidates can be applied prior to welding and seal the faying surface gaps in lap …

Design Hazard Analysis, And System Level Testing Of A University Propulsion System For Spacecraft Application, Joseph R. Siebert

Masters Theses

"The Missouri Science and Technology Satellite (M-SAT) design team on the campus of the Missouri University of Science and Technology has developed a pair of satellites to perform an autonomous formation flight mission. To enable the mission, a unique cold gas propulsion system was developed which utilizes the refrigerant R-134a as propellant. This thesis details the design process and considerations which led to the propulsion system as integrated into the satellite for the Flight Competition Review of the NS4 competition. The design process described flowed from the mission requirements and program restrictions down through component-level requirements and resulted in a …

Communication Models For Monitoring And Mobility Verification In Mission Critical Wireless Networks, Maheswaran Thiagarajan

Masters Theses

"Recent technological advances have seen wireless sensor networks emerge as an interesting research topic because of its ability to realize mission critical applications like in military or wildfire detection. The first part of the thesis focuses on the development of a novel communication scheme referred here as a distributed wireless critical information-aware maintenance network (DWCIMN), which is presented for preventive maintenance of network-centric dynamic systems. The proposed communication scheme addresses quality of service (QoS) issues by using a combination of a head-of-the-line queuing scheme, efficient bandwidth allocation, weight-based backoff mechanism, and a distributed power control scheme. A thorough analysis of …

Decision-Based Design Under Uncertainty With Intervals, Sashank Vasireddy

Masters Theses

"Design requires a series of decisions, and one of the major challenges engineering designers face is making decisions under uncertainty. The engineering designer must choose the best design among various alternatives. This work evaluates the use of utility functions to make decisions under uncertainty with both random and interval variables. Uncertainty cannot be eliminated completely, but it can be reduced. Most current methods treat only aleatory uncertainty. Here, however, both aleatory and epistemic uncertainties are addressed in the context of engineering design. Methods such as moment matching method and worst case analysis are used to incorporate uncertainty into design problems"--Abstract, …

The Corrosion Of Ni₃Si Alloys In Sulfuric Acid, Christopher Marc Larson

Masters Theses

"Hydrogen production from water, the world's most renewable natural resource, can provide an economical and sustainable form of energy for the future. One means to achieve this is with a nuclear reactor-based sulfur-iodine (S-I) thermochemical cycle. Currently there are few materials available, other than precious metals like gold and platinum, that possess the corrosion resistance and mechanical properties required for the sulfuric acid decomposition loop of the S-I process. However, alloys based on Ni₃Si show promise to be a more affordable, corrosion resistant materials option for this technology. In this study, the corrosion behavior of NiSi₂₂ and NiSi₂₀(Nb,Ti)₃ alloys in …