Engineering Commons^™

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 …

Analogy Based Modeling Of Natural Convection, Vaibhav Khane

Masters Theses

"This research is an extension of previous work on the development of an integrator or resistance-capacitance circuit analogy for natural convection. As a part of a larger project to enhance transport phenomenon on a micro-scale using radiation, this work studied the phenomenon of natural convection. Using experimental techniques and numerical simulations (FLUENT code), it investigated the transient response of a natural convection system. It proposes an integrator circuit analogy for a natural convection system. Experimental investigation with three different fluids indicated that the characteristic time constant of the system is related to the Prandtl number of the fluid. The project …

Comparison Of In-Planta Sampling Methods For Delineating Groundwater Contaminants, Kendra Marie Waltermire

Masters Theses

"Plants directly interact with surrounding water, air, and soil, collecting and storing chemicals and elements from the surrounding environment. Two new and innovative sampling methods have been developed in which this valuable data can be accessed to replace as well as supplement contaminated-site investigations. When determining the extent of the plume on a contaminated site, groundwater sampling may be limited due to time, site access, and expense. Using new techniques that place sampling devices in trees on site, we can sample trees naturally occurring on a contaminated site or those planted in phytoremediation or redevelopment efforts. Using these sampling devices, …

Development Of Extrusion On Demand For Ceramic Freeze-Form Extrusion Fabrication Processes, Parimal Sanjay Kulkarni

Masters Theses

"Freeze-form Extrusion Fabrication (FEF) is a Solid Freeform Fabrication method. It involves the deposition of a ceramic paste in a layer by layer manner to construct a three dimensional structure. The ceramic paste used in this process consists of a high solids loading of ceramic powder mixed with water and a nominal amount of an aqueous organic binder. These characteristics make the process environmentally friendly. Also the absence of dies or molds in the process makes it suitable for fabrication of materials like ceramics. In the past, parts have been fabricated with continuous extrusion of a ceramic paste. In FEF, …

Inductance Modeling And Extraction In Emc Applications, Clint Matthew Patton

Masters Theses

"Inductance has become a challenging problem for EMC engineers in many applications. Regardless of the application at hand, the first step remains the same; return to the physics and trace the current paths. IGBTs have become an important part in the design of power electronics because of their ability to switch fast and with stand high currents. Modules used for three phase motor drives often create problems when neglected parasitic components show themselves and interfere with the performance of the desired operation of a system. Many manufactures of these modules do not give out equivalent circuit modules and therefore leave …

An Analysis Of Lessons Learned And Best Practices From Fuel Cell Applications With An Emphasis On Hydrogen Technology, Clint Alex Cottrell

Masters Theses

"In its review of the Department of Energy's Research Development and Demonstration (RD&D) plan for hydrogen, the National Academies recommended a study of lessons learned from technologies developed for stationary fuel cell power systems. Thus, the motivation for this thesis is to study and identify the lessons learned and best practices from prior stationary fuel cell power programs. To understand how to prepare for this technology, this study conducted a thorough investigation of past stationary alternative power projects to assess the opportunities for future stationary power efforts, and how this information can be used to meet objectives for future fuel …

Application Of Ground Penetrating Radar (Gpr) For Bridge Deck Condition Assessment: Using A 1.5 Ghz Ground-Coupled Antenna, Amos Wamweya

Masters Theses

"This study is a GPR-based assessment of three bridge decks, two with a hot bituminous wearing surface and one with a bare concrete slab. The primary objectives of this study were: 1) to assess the integrity of the three bridge decks using a 1.5 GHz ground-coupled GPR antenna, and 2) to evaluate the utility of the 1.5 GHz ground-coupled antenna for bridge deck investigations. Core control (chloride ion concentration data and core integrity data) and visual inspection were used as interpretive constraint. The acquired GPR data were interpreted, and two plan view maps were generated. One depicts the magnitude of …

Public-Private Partnerships In High Risk Transportation Projects, Kiran Rangarajan

Masters Theses

"This research examines Public-Private Partnerships (PPPs) between private firms and City of Chamois, Missouri to establish a ferry boat service across the Missouri River. The study illustrates the role of PPPs in managing high risk transportation projects for rural economic development. The research study was designed to accomplish three objectives. First, understand and study the high risk transportation industry which included analyzing other ferry services in and around the region, and identifying potential risks involved in a ferry boat project. Second, study various models of PPPs, identify the attributes of each model and select appropriate models based on local and …

Investment Shell Cracking, Edward A. Druschitz

Masters Theses

"Shell cracking is the single greatest problem affecting investment casters. A clearer understanding of the factors affecting the melt profile of the wax can be gained using computational fluid dynamics (CFD) to model the interaction among 1) the thermal conductivity of the wax, 2) the thermal conductivity of the shell, and 3) the temperature of the autoclave during the autoclave de-waxing cycle. The most favorable melt profile results from a high autoclave temperature (438⁰K to 458⁰K) and saturated thermal conductivity of the shell (1.36 to 1.40 Wm⁻¹k⁻¹) in conjunction with a low wax thermal conductivity (0.33 Wm⁻¹k⁻¹). These parameters reduce …

Project Collaboration In A Distributed Environment, Shriroopa Prabhakar Deshpande

Masters Theses

"This thesis investigates methods of managing projects in an environment where project team members are in different locations. Today, large scale projects undertaken by firms that have a global presence are successfully developed across time, distance, and geographic boundaries. In order to survive in this environment, firms face many project challenges, including diverse employees, various work practices, and communication issues. Many communication issues can be minimized by the proper use of collaborative tools as well as by sharing expertise, coordinating activities, and managing relationships. Web-enabled project management tools have enhanced efforts to increase the quality, competitiveness, and profitability of these …

Emi Chip-To-Tem Cell Coupling For A Microcontroller And Emi Coupling Resulting From Via Transition And Reference Plane Change, Hemant Bishnoi

Masters Theses

"The work presented in this thesis can be broadly categorized under two main headings, estimation of electromagnetic interference (EMI) performance and characterization of EMI performance.

A numerical model of capacitive coupling between two orthogonally crossing double stripline was developed earlier by Kenji Araki and Yoshio Kami at the University of Electro-Communications, Japan. Their model was shown to be accurate up to 3GHz. A verification of their numerical model with full wave simulations is presented here.

In another work done by Shaohua Li, dynamic currents in the power pins of a microcontroller were predicted by using an IC model. The ultimate …

Adapting Management Strategies To Enter New Global Markets, Karuna Vineetha Vemulapalli

Masters Theses

"With globalization spreading its roots into every country, people from various countries are working together, and will be trying to understand the cultural differences between the organizations in different nations. Effective management of the cultural differences will be an important and competitive advantage. Keeping in mind the different perceptions of the term “Management” by varying cultures, namely United States and India, this research will be focused on understanding and managing these differences.

The proposed research will deal with concepts of cultural diversity, economic differences, intercultural and organizational differences between the two countries. Understanding why some factors like motivation, responsibility, and …

Design And Implementation Of An Asynchronous Null Convention Logic (Ncl) Fpga, Indira Priyadarshini Dugganapally

Masters Theses

"This Master’s thesis outlines the design of a completely asynchronous Field Programmable Gate Array (FPGA) for implementing NULL Convention Logic (NCL) digital circuits. The proposed design uses four Configurable Logic Blocks (CLB), each of which in turn is designed using four Logic Elements (LE) to implement NCL logic function. Each LE can be configured to function as any one of the 27 fundamental NCL gates. A Logic Element is designed by concatenating a Look-Up-Table (LUT) with a pull-up pull-down transistor chain and a hysteresis loop. The interconnections and the switch box are designed using pass transistors and SRAM. In this …

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, …

Friction Stir Processing Of Magnesium Alloys, Gaurav Bhargava

Masters Theses

"Magnesium alloys have been fast catching up their attention in applications where both lightweight and exceptional strength is desired. But magnesium alloys suffer formability issues which limit their use to cast applications when designing complicated shapes. Friction stir processing (FSP) is technique for, imparting a fine-grained, homogeneous microstructure by which both strength and ductility can be enhanced. The results from the first part of present work showed that AZ31 alloy when employed the use of FSP, yielded significant strength and ductility gains but on the cost of anisotropy. The cause of anisotropy was investigated to be correlated to texture evolution …

Synthesis Of Surface Composites Using Friction Stir Processing, Bharat Gattu

Masters Theses

"Composite materials have an edge over monolithic materials due to higher strength/stiffness - to - density ratios, improved fatigue and wear resistance and better high temperature properties. Surface composites provide improved tribological properties such as wear resistance, friction coefficient and corrosion resistance. Friction stir processing (FSP) which originated from friction stir welding (FSW - a method for joining aluminum alloys) is a solid state technique to modify the microstructure of the alloys. During FSP the frictional heat generated at the tool - work piece interface plasticizes the material allowing it to flow around the pin. The combined effect of the …

Development And Use Of Computer Aided Tools To Enhance Team Dynamics With Role Play Simulations, Vachaspathy Kuntamukkala

Masters Theses

"This thesis proposes a methodology for the development and use of computer based tools to enhance student team dynamics. Working effectively in groups cannot be taught in class room environment. Students often encounter conflicts during team meetings. Although some conflicts are resolved by the efforts of team members, an unbiased facilitator who is not a member of the team is often needed to help. This work proposes a tool that uses role play simulations to engage students in real-life scenarios so that they gain a practical, as well as a theoretical, understanding of how to work effectively as a team. …

Anchorage And Bond Characteristics Of Externally Bonded Frp Laminates Used For Shear Strengthening Of Rc And Pc Girders, Carlos Andres Ortega Ordonez

Masters Theses

"In the last three decades, the use of fiber reinforced polymer (FRP) materials to strengthen structures externally has emerged as one of the most promising technologies in materials and structural engineering, and these materials have been gaining popularity in the civil engineering community. Externally bonded FRP sheets and laminates have been used successfully to increase flexural and shear capacity. The overall performance of the strengthened system depends heavily on the quality of the bond between the concrete and the FRP laminate. Low bond strength can cause delamination at the fiber-matrix interface and at the FRP laminate-concrete interface. As a result, …

In-Plane Behavior Of Strengthened Unreinforced Masonry Infill Walls With Alternative Wood-Fiber Fly Ash Material, Yosuke Tanizawa

Masters Theses

"This research investigates the potential for an alternative masonry product to use in masonry infill wall systems. The study also investigates the effects of an external fiber reinforced polymer (FRP) strengthening system on in-plane behavior of the alternative unreinforced masonry (URM) walls. The alternative masonry product is produced in a solid unit configuration and utilizes recycled white oak wood-fibers and an ASTM Class-C fly ash as its raw materials. The external strengthening system investigated consists of an elastomeric polyurea surface coating with and without integrated discrete chopped E-glass fibers which is directly sprayed on the URM wall surfaces. The alternative …

The Effects Of Water To Fuel Ratio On The Kinetics Of Supercritical Water Reformation Of Jet Fuel, Satya Putta

Masters Theses

"The noncatalytic direct reformation of jet fuel was studied in a supercritical water medium using a specially designed 400-mL Haynes® 230 alloy tubular reactor. The experiments were conducted at 1042±5 K, 240.9±0.1 bar, and at water flow rates of 7.5, 15, 30 g/min with varying water-to-fuel feed ratios of 7.5, 15 and 30. The principal reactions are direct reformation of jet fuel into hydrogen and carbon oxides and pyrolysis of jet fuel into lighter hydrocarbons and coke. The effluent gas contained H₂, CO, CO₂ and CH₄, with smaller concentrations of C₂H₄ and C₂H₆. This thesis discusses the effects of the …

The Development And Application Of The Complete Time-Domain Trl Calibration Technique, Hongxia Ning

Masters Theses

"The first paper in the thesis discussed the development of a complete time-domain THRU-REFLECT-LINE (t-TRL) calibration technique. To validate the error correction technique, two stripline TRL test fixtures are designed and measured by two TDR instruments respectively. The t-TRL calibration is implemented to the recorded TDR/TDT waveforms and the comparison of the magnitude and phase results of S-parameters obtained by t-TRL and VNA TRL shows excellent agreement up to 25GHz.

In the second paper, the application of t-TRL calibration technique to the Root Impulse Energy (RIE) loss calculation is discussed. The RIE loss is theoretically derived for the matched network …

Investigation Of Selective Laser Sintering Of Zirconium Diboride Parts, Shashwatashish Pattnaik

Masters Theses

"This research investigates the fabrication of three-dimensional parts from ZrB₂, an ultra high temperature ceramic (UHTC), using the selective laser sintering (SLS) process. Based on an experimental investigation, optimum values for the SLS parameters (scan speed, laser power, energy density, scan spacing and layer thickness), used on a DTM Sinterstation 2000, were determined to build green ZrB₂ parts with high integrity and sharp geometrical features. This was done by melting the polymer binder used to bond the ceramic particles layer-by-layer according to the cross-section of a CAD model. The use of a sacrificial plate to eliminate cracks in the bottom …

An Evolutionary Algorithm Approach To Actuated Signal Timing Optimization Under Lane-By-Lane Detection Condition, Eric G. Strack

Masters Theses

"Motivated by the need to reduce congestion on the nation's roadway network, this research seeks to determine when a new detection scheme at actuated signalized intersections may help. This new detection scheme is called lane-by-lane detection. It "looks" at traffic in all lanes individually to determine the traffic volume on the roadway. Specifically, the problems addressed are investigating alternate signal timings and investigating the traffic volume's effect on performance of the detection scheme. For the alternate signal timings, an Evolutionary Algorithm (EA) was employed to identify the optimal signal timing. This algorithm creates signal timings and tests them in the …

Het-Cam For The Identification Of Ocular Irritancy In Seawater/Salt Water Sources, Alexander Clovis Winters

Masters Theses

"The Hens Egg Test on the Chorionallantoic Membrane (HET-CAM) is an ocular irritation test proposed to replace tradition ocular investigations such as the Draize eye test that has been criticized because of its use of animals. In this study, the ocular irritation potential of seawater and saltwater sources dosed with different disinfectants has been evaluated using the HET-CAM. The seawater and salt water tested was taken from the main show pools from three aquatic theme parks (San Diego, San Antonio, and Orlando). The three disinfectants considered were sodium hypochlorite (NaOCl), calcium hypochlorite (Ca(OCl)₂), and ozone (O₃).

Three different HET-CAM methods …

Generation And Analysis Of Fcg Data Using A Single Specimen And Kmax - ∆K Testing Matrix, Sree Phani Chandar Reddy

Masters Theses

A custom method to generate fatigue crack growth (FCG) data requires testing of multiple specimens at different load ratios. In addition, it includes the application of a load shedding procedure from pre-cracking level to threshold.

In this thesis, a novel method of testing has been investigated that utilizes a single specimen and a testing matrix in terms of K_maxand ∆K values corresponding to predetermined R-ratios for which FCG data, da/dN, are recorded. Automatic K-controlled tests on 2324-T39 Al alloy were conducted using the ∆K increasing and ∆K decreasing procedures while K_maxwas kept constant. Results show that …

Global Skin Friction Diagnostics In Complex Separated Flows, Sudesh A. Woodiga

Masters Theses

This work describes the application of a global luminescent oil film skin friction meter to quantitative global skin friction diagnostics in complex separated flows. The development of this technique is based on the relationship between the oil film thickness and luminescent intensity of an oil film mixed with a luminescent dye. The projected thin oil film equation is given to relate the normalized luminescent intensity with skin friction. The basis for this technique is the variational solution for the thin oil film equation on the image plane. The variational formulation with a smoothness constraint on skin friction is proposed to …

Ductile-Regime Machining Of Silicon Carbide And Quartz, Deepak Ravindra

Masters Theses

Silicon carbide (SiC) and quartz are one of the advanced engineered ceramic materials designed to operate in extreme environments. One of the main reasons for the choice of these materials is due to its excellent electrical, mechanical and optical properties that benefit the semiconductor, MEMS and optoelectronic industry respectively. Manufacturing these materials is extremely challenging due to its high hardness, brittle characteristics and poor machinability. Severe fracture can result when trying to machine SiC and quartz due to its low fracture toughness. However, from past and current research efforts, it has been proven that ductile regime machining of brittle materials …

Prediction Of Fatigue Crack Growth Retardation Due To A Tensile Overload Using Two-Parameter (∆K, Kmax) Approach, Wataru Tsutsui

Masters Theses

A theoretical crack growth study on powder metallurgy aluminum alloys AA5091 and AA8022 was conducted. Specifically, the research focused on the crack growth retardation due to the application of a tensile overload. The tensile overload creates a plastic zone ahead of the propagating crack tip that induces the compressive residual stress after unloading. Such compressive residual stress pushes the crack tip faces against each other, which results in crack growth retardation.

In the study, simulation started from the calculation of the compressive residual stress. The details of the calculation steps are explained in the thesis. Eventually, the stress intensity factor …

Incorporation Of Space Syntax Theory In Determining Safe And Efficient Construction Site Layout, Minsuck Cho

Masters Theses

Facility layout is an important to determine a proper arrangement of temporary facilities in a construction site. It significantly impacts productivity and safety of construction. The objectives of layout planning are to minimize travel distance and time, to decrease the facility transportation and setup costs, and to improve site safety. Despite the importance of facility layout, it is often overlooked in the planning phase. Several models have been developed taking some of these factors into consideration; however, construction managers and site planners often regard cost as the most important factor in layout planning and pay less attention to safety and …