Digital Commons Network^™

An Examination Of The Effectiveness Of Differing Types Of Feedback Across Controlled Written Assignment Scenarios, Lisa Dopke

Masters Theses

The development of effective writing skills is widely acknowledged as a primary goal in higher education. For this reason, instructors have devised several ways to help students develop and improve their writing proficiency. Within this repertoire of strategies, the most common and often most practical method is providing feedback, particularly written feedback, on student’s writing assignments. Because feedback is commonly recognized as advantageous in this respect, and because there continues to be a keen “interest in how to provide more effective, relevant feedback to students” (Wiltse, 2002, p. 127), various aspects of the feedback communication and related processes have been …

Inclusion Modification In Steel Castings Using Automated Inclusion Analysis, Vintee Singh

Masters Theses

"The objective of this research is to study the effects of changing the melt and ladle practices (deoxidation, slag, refractory types, etc.) in steel foundries on the cleanliness and toughness of steel castings. This study used an automated inclusion analyzer ASPEX PICA-1020, which provides a rapid and accurate method for determining the composition, size, number, and spacing of the inclusions present in steel samples. The first step in this research was to complete a series of industrial tests to benchmark the current foundry ladle practices with respect to cleanliness of the cast steel. Trials were conducted at steel foundries using …

The Effect Of Near-Surface Metallurgy On The Machinability Of Cast Iron, William Dewey Peach

Masters Theses

"The increasing performance and durability of cutting tool inserts have created metallurgical challenges for production foundries to produce near-net shaped castings within strict dimensional tolerances. In order for foundries to take full advantage of the increased cutting speed capabilities, it becomes necessary to reduce machining allowances and produce much more stable casting surfaces. To accomplish this, a better understanding of the complex microstructures formed within the first 0.120 in. (3 mm) of the mold/metal interface (as-cast surface) is necessary. The goal of the work presented here was to examine the microstructures formed in the near-surface region of gray iron castings, …

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 …

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 …

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.

Comparison Of Dashboard-Based And Balanced Scorecard-Based Corporate Performance Management System, Lin Zhu

Masters Theses

"Under current hypercompetitive and technology driven economic environment, more companies are using a corporate performance management (CPM) system to gain more accurate understandings of the company goals and strategies and to craft methods of achieving those goals and strategies. While CPM systems are generally implemented in two approaches: dashboard approach and scorecard approach, very few studies examine the effectiveness of each type of CPM systems implementation. Therefore, the main objective of this study is to assess the effectiveness of a dashboard based and a balanced scorecard based corporate performance management system. The effectiveness is examined through management effectiveness, degree of …

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 …

Quench Factor Analysis Of Wrought And Cast Aluminum Alloys, Vishwanath Gandikota

Masters Theses

"Mechanical property variation across the cross section of heat treatable aluminum alloys is a major concern. To minimize such variation, a proper understanding of kinetic transformations and estimation of mechanical properties is required. The Jominy end quench test has been used successfully to study the effect of quench rate on the final heat treated properties of wrought and cast aluminum alloys. This test produces varying cooling rates along the length of a cylindrical sample cooled with water at one end. Jominy bars of wrought and cast aluminum alloys were solutionized, endquenched, and aged to T6 temper condition after delays of …

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 …

The Effects Of Technology On Literacy(S), Thomas Glen Petersen

Masters Theses

"One of the challenges when measuring the effects of technology on literacy(s) is finding a control group where technology; does not play a major role in the culture. The Amish successfully live in a Technocracy where mechanical/electronic tools are used only when absolutely necessary; the Amish are not dependent on them for survival. The crux of the Amish philosophy is humility, serving the community and serving God. Ironically, they have suffered tremendous repercussions for adopting a wholesome, selfless lifestyle which is contrary to most popular world views, regardless of religious or spiritual views"--Purpose, page 40.

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 …

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 …

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 …

Continuous Control Of Lunar Orbits Via Electric Propulsion, Sunil Aggarwal

Masters Theses

"To find definite answers for the presence of water on the poles of Moon, to facilitate selection of future lunar landing sites and aid in construction of architectural bases, to assist proper lunar resource utilization and to improve lunar gravity models there is a great interest and need for highly accurate, reliable and efficient lunar surface mapping and communication. This thesis is intended to aid in proper selection of orbits for future lunar missions by demonstrating the impact of using electric propulsion on the search space of feasible and useful lunar orbits. The requirements for future lunar mapping and communication …

Verifying Module Heuristics For Large Scale Products, Rachel Marie Day

Masters Theses

"Decreasing time and costs is a major objective in many businesses today. Including modularity in the early design phases can effectively decrease time spent on and costs associated with a project. The task of identifying modules within a product early in the design process (when decisions are less expensive) is made less daunting by using the techniques of functional modeling and module heuristics. The two papers that form this thesis discuss the results of the efforts to verify the module heuristics on large products. Observations on needed modifications to the functional modeling technique and original module heuristics are reported along …

Modeling And Simulation Of Electrochemical Magneto Hydro Dynamics, Debamoy Sen

Masters Theses

"This thesis focuses on how the electrochemical magneto hydro dynamic problem is solved through numerical simulation for a two dimensional millielectrode electrochemical cell and a three dimensional microelectrode array cell. Electrochemical processes are enhanced by magnetic fields through the introduction of body forces such as Lorentz force. Through modeling and numerical simulations, experimental results can be integrated with theory. Such simulations will aid in the prediction of mass transfer limited currents and visualization of flow profiles in an electrochemical cell. The numerical solution of the equation system is made possible by the finite volume method used in the FLUENT Computational …

Electricity Generation And Ethanol Production Using Iron-Reducing, Haloalkaliphilic Bacteria, Varun Paul

Masters Theses

"Microbial life in extreme environments has been studied primarily for their metabolic activities. Very few commercial or industrial applications have been known from these systems. In this study, the metabolic pathways and properties of bacteria from a haloalkaliphilic environment of Soap Lake, Washington were employed in two research applications related to energy production. In the first study, the bacterial cultures that were known to reduce iron (III) were used in a Microbial Fuel Cell (MFC) reactor. Iron reducing bacteria have shown to shunt their electrons on to the surface of a carbon electrode of an MFC, and the electrons can …

Exploring The Use Of A Commercial Game Engine For The Development Of Educational Software, Hussain Alafaireet

Masters Theses

"Three-dimensional visualization and simulation environments are becoming increasingly important in both industrial and educational environments. However, developing these simulations can be a difficult and expensive task. Herein we explore the use of a commercial game engine to develop a 3-D, interactive computer game designed to teach players about the anatomy of a frog. The goal of this project is threefold: 1) to develop high-fidelity virtual reality educational software with a limited budget and limited personnel, 2) to define a software development process by which similar simulations can be developed, and 3) to explore the benefits that these simulations provide to …

Development And Evaluation Of An Effective Process For The Recovery Of Oil And Detoxification Of Meal From Jatropha Curcas, Sarthak Gaur

Masters Theses

"There has been significant research on biofuels to ensure national security and economic stability of the US. Jatropha curcas, a hardy plant, holds tremendous potential as a biodiesel source and cattle feed-stock largely due to its high triglyceride and crude protein content. However, its viable economic utilization is limited due to the presence of important toxic compounds, phorbol esters. A novel and efficient process has been developed that obtains high yields of jatropha oil and detoxifies the defatted (oil free) jatropha meal. Principles of solid-liquid extraction were utilized to detoxify the meal and then liquid chromatography was employed to analyze …

Control Aspects Of A Double-Input Buckboost Power Electronic Converter, Deepak Somayajula

Masters Theses

"Systems in which two or more energy sources combine to supply power to a common load are called hybrid energy systems. Applications of these systems have grown due to their flexibility and reliability. Hybrid energy systems have been successfully implemented in hybrid electric vehicles and wind-solar systems where two or more energy sources share the same load. Double-input (DI) dc-dc power electronic converters (DIPECs) have been gaining popularity in hybrid energy systems due to their reduced component count and control simplicity. In addition, employing DIPECs increases the reliability, stability, and flexibility of the system. In this thesis, a small-signal model …

Screw Connections Subject To Tension Pull-Out And Shear Forces, Ryan M. Francka

Masters Theses

"Currently, the behavior of screw connections subject to combined tension pull-out and shear forces is not well understood. An experimental study was conducted at Missouri University of Science and Technology to better understand the relationship or interaction between these forces. The test program evaluated four parameters that may influence the behavior of pure tension and pure shear in screw connections: the thickness of the sheet not in contact with the screw head, the ultimate strength of the steel, the ductility of the steel, and the screw diameter. This investigation extends the application of the pure pull-out and pure shear equations …

Fault Detection And Prediction With Application To Rotating Machinery, Gary R. Halligan

Masters Theses

"In this thesis, the detection and prediction of faults in rotating machinery is undertaken and presented in two papers. In the first paper, Principal Component Analysis (PCA), a well known data-driven dimension reduction technique, is applied to data for normal operation and four fault conditions from a one-half horsepower centrifugal water pump. Fault isolation in this scheme is done by observing the location of the data points in the Principal Component domain, and the time to failure (TTF) is calculated by applying statistical regression on the resulting PC scores. The application of the proposed scheme demonstrated that PCA was able …

Formation Of Iron-Rimmed Sandstone Nodules On Earth; Terrestrial Analogue For The Formation Of Martian Blueberries?, Katherine Charlotte Muller

Masters Theses

"NASA's twin Mars Exploration Rovers, MER, Spirit and Opportunity, have identified numerous geologic features that hint at a watery past on Mars noted in Malik, 2004. Prominent among these features are the "Martian Blueberries" that occur as spherical hematite (Fe₂O₃) nodules. Hematite formation is facilitated by the presence of water, although there are presently no known sources of free liquid water on Mars. Chan et al., 2004 states that these "blueberries" are also similar to nodules found in the Jurassic aged Navajo Sandstone in Utah. An understanding of the processes controlling the formation of the Utah nodules may thus be …

Nona-Arginine Peptides Facilitate Cellular Entry Of Semiconductor Nanocrystals: Mechanisms Of Uptake, Yi Xu

Masters Theses

"Luminescent semiconductor quantum dots (QDs) have recently been used for delivering and monitoring biomolecules, such as drugs and proteins. However, QDs alone have a very low efficiency of transport across the plasma membrane. In order to increase the efficiency of QD delivery, synthetic nona-arginine (sR9) was used, a cell penetrating peptide, to facilitate uptake. Data demonstrated that sR9 could significantly increase the cellular uptake of QDs by noncovalent binding between QDs and sR9. Furthermore, the mechanisms of QD/sR9 cellular internalization were investigated. Low temperature and metabolic inhibitors markedly inhibited the uptake of QD/sR9, indicating that internalization is an energy-dependent process. …

Feasibility Of A Human Performance Model In Consequence Management, Kashmeera Ghosh

Masters Theses

"Human civilization has always encountered unpredictable disasters as a result of natural events. Now it also faces the disasters caused by terrorist attacks. Governments must have consequence management plans in place to protect public health and safety, restore essential services, and provide emergency relief to affected businesses and individuals. Human performance models predict outcomes in complex dynamic situations. Such models can simulate disaster management procedures under varying circumstances. This work applies human performance modeling in a terrorist situation and evaluates possible uses of such models by first responders in practical consequence management applications. It includes a case study of an …