Engineering Commons^™

Low-Thrust Control Of A Lunar Orbiter, Nathan Harl

Masters Theses

"This thesis presents a method for maintaining a long-term lunar Sun-synchronous orbit using continuous low-thrust hardware. The control method is developed using optimal control theory, which involves controlling a system through the minimization of a desired cost function"--Abstract, page iii.

Operation Of A Brushless Dc Drive For Application In Hybrid Electric Vehicles, James Scott Jenkins

Masters Theses

"One of the goals of a hybrid electric vehicle design is to improve the overall performance of the vehicle by incorporating several different power sources in such a way as to maximize the energy usage. By combining the desirable characteristics of each of the components in the system, the vehicle becomes more efficient to operate. Energy storage systems such as batteries and ultra-capacitors can be used to supply or store energy from the system when needed. The primary power source in this model will be an internal combustion engine coupled with a permanent magnet synchronous generator. The purpose of this …

Distribution System Operation And Planning In The Presence Of Distributed Generation Technology, Gavin Wesley Jones

Masters Theses

"Distributed generation (DG) is becoming an increasingly attractive power generation paradigm in the field of power engineering as economic and environmental factors drive new technologies to be more efficient and less polluting than their earlier counterparts. Although the concept of DG is not new, little research has been done on the topic and even fewer field tests have been performed. This lack of research, along with other factors, has somewhat slowed the acceptance of DG into markets, other than industrial or commercial co-generation for heat and power. This thesis attempts to examine and compare three types of DG: diesel generators, …

Process Development And Applications Of A Dry Film Photoresist, Phaninder R. Kanikella

Masters Theses

"In this study, dry film photoresist was patterned using UV lithography and the sidewall profile was optimized to achieve vertical sidewalls. Sidewall verticality of dry film is very important for better pattern transfer"--Abstract, page iv.

Converting Some Global Optimization Problems To Mixed Integer Linear Problems Using Piecewise Linear Approximations, Manish Kumar

Masters Theses

"Some global optimization problems are converted to mixed-integer linear problems (MILP) using piecewise-linear approximations in this thesis so that they can be solved using commercial MILP solvers, such as CPLEX. Special attention is given to approximating two-term log-sum functions, which appears frequently in generalized geometric programming problems. Numerical results indicate the proposed approach is sound and efficient"--Abstract, page iii.

Real-Time Detection Of Grip Length Deviation For Fastening Operations: A Mahalanobis-Taguchi System (Mts) Based Approach, Deepak Mohan

Masters Theses

"Hand-held fastening tools are extensively used in manufacturing, especially in aerospace industry. Typically, the process is monitored by the operator and joints are visually inspected after the process is completed. When complex products, such as an aircraft, are considered, fastening process and its inspection can be very time consuming. In addition, no inspection data is typically collected during the process unless a major problem is encountered. Real-time monitoring and verification of the fastening process of joint quality are two important advancements to reduce the manufacturing lead time while ensuring safety and quality"--Abstract, page iv.

Performance Improvements Of Automobile Communication Protocols In Electromagnetic Interference Environments, Fei Ren

Masters Theses

"Electromagnetic Interference (EMI) is frequently encountered in automobile communication systems due to a large number of inductive nodes used in these systems. This thesis investigates the effects of EMI on two types of automobile communication systems, the Controller Area Network (CAN) and the FlexRay. It also proposes a modified Automatic Repeat reQuest (ARQ) scheme to improve the communication performances in EMI environments"--Abstract, page iii.

Best Practices For Implementing A Biodiesel Program, Sundaresan Sadashivam

Masters Theses

"The Missouri Department of Transportation (MoDOT) has a mandate to utilize biodiesel blends in its fleets. However, they have not been able to meet this requirement due to various implementation issues. Therefore, this thesis presents a study to determine the best practices for implementing a biodiesel program. The study was conducted by soliciting information from Departments of Transportation and other agencies related to their biodiesel programs and practices. A list of best practices was developed and the Analytic Hierarchy Process (AHP) was used to prioritize this list of best practices"--Abstract, page iv.

Refrigerant-Based Propulsion System For Small Spacecraft, Carl Reiner Seubert

Masters Theses

"The MR SAT spacecraft under development at UMR requires a propulsion system that can be utilized to perform orbital maneuvers and three-axis attitude control to complete its mission objective of conducting spacecraft formation flight. This thesis documents the research, analysis design and development of the cold gas propulsion system that was integrated on the MR SAT spacecraft"--Abstract, page iii.

Properties Of Alkaline-Resistant Calcium-Iron-Phosphate Glasses, Jiawanjun Shi

Masters Theses

"The physical properties and alkaline corrosion resistant properties of calcium-iron-phosphate glasses were studied. The addition of Fe₂O₃ decreases the thermal expansion coefficient and increases the glass fiber's Young's modulus in comparison with the addition of CaO. Bulk glass dissolution behavior in alkaline Lawrence solution was studied by weight loss experiments, Raman spectroscopy, and analytical scanning electron microscopy. The corrosion of glass powder in NaOH solution was studied by X-ray diffraction, infrared spectroscopy and high pressure liquid chromatography. The results show that the dissolution rate decreases when the phosphate chain length decreases. Calcium oxide can improve the glass durability in high …

Robust Mechanism Synthesis With Random And Interval Variables, Pavan Kumar Venigella

Masters Theses

"Robust mechanism synthesis ensures that the performance of a mechanism is not sensitive to uncertainties in the mechanism and its environment. The uncertainties include the dimension variations, installation errors, random input motion, and various external forces. Robust mechanism synthesis is used to minimize the impact of these uncertainties on the mechanism performance. Robust mechanism synthesis has been performed by either a probabilistic approach or a worst case approach. The former approach describes uncertain parameters as random variables while the latter approach treats uncertain parameters as interval variables. In this work, methods are developed for robustness assessment and robust mechanism synthesis …

Empirical Dynamic Modeling And Nonlinear Force Control Of Friction Stir Welding, Xin Zhao

Masters Theses

"Current Friction Stir Welding (FSW) process models are mainly concerned with the detailed analysis of material flow, heat generation, etc. and therefore, are computationally intensive. Dynamic models describing the total forces acting on the tool throughout the entire welding process are required for the design of feedback control strategies and improved process planning and analysis. In this thesis, empirical models relating the process parameters (i.e., plunge depth, travel speed, and rotation speed) to the process variables (i.e., axial, path, and normal forces) are developed to describe their dynamic relationships"--Abstract, page iv.

Modeling And Control Of Freeze-Form Extrusion Fabrication, Xiyue Zhao

Masters Theses

"Freeze-form Extrusion Fabrication (FEF) is an additive manufacturing technique that extrudes ceramic loaded aqueous pastes layer by layer below the paste freezing temperature for component fabrication. As the FEF is aimed at being conducted at low environmental temperatures, down to -20°C, it is necessary to investigate the effect of environmental temperature on the process. The advantages of fabrication at low temperature have been proved by experiments. Comparisons in terms of operation parameters, self-sustaining ability, and system dynamic response were performed at different environmental temperatures ranging from 20°C to -20°C.

It is commonly known in paste extrusion processes that due to …

Fast Sphere Decoder For Mimo Systems, Praveen G. Krishnan

Masters Theses

"This work focuses on variants of the conventional sphere decoding technique for Multi Input Multi Output (MIMO) systems. Space Time Block Codes (STBC) have emerged as a popular way of transmitting data over multiple antennas achieving the right balance between diversity and spatial multiplexing. The Maximum Likelihood (ML) technique is a conventional way of decoding the transmitted information from the received data, but at the cost of increased complexity. The sphere decoder algorithm is a sub-optimal decoding technique that is computationally efficient achieving a ;symbol error rate that is dependent on the initial radius of the sphere. In this thesis, …

Fine Particle Classification Using Dilute Fluidized Beds, Rajasekharan Pillai Annapoorneswari

Masters Theses

"The main objective of this project is to classify spherical soda-lime glass particles based on their size using a dilute fluidized bed system. The influence of inclined plates in the column, plate separation, plate inclination, and number of plates on the overall separation efficiency of particles will be investigated. The effect of column shape on the classification efficiency will also be assessed"--Introduction, page 3.

Characterization Of Noise On Pdn And Electromagnetic Shielding, Sandeep K. R. Chandra

Masters Theses

"Modern FPGA and microprocessor have complex logic inside them, which draw current from the Power Distribution Network (PDN). This current drawn from the PDN creates disturbance on the PDN, which then propagates to other IC in different places on the Printed Circuit Board (PCB), and appears as a noise voltage. Ability to predict noise voltage at any point on the PCB gives a greater ability to carefully design the board and the PDN. In order to accurately predict the noise, it is important to accurately predict the current drawn and the transfer impedance from the source to the victim point. …

Computational Study Of Flow Over Elliptic Airfoils For Rotor/Wing Unmanned Aerial Vehicle Applications, Timothy William Assel

Masters Theses

"The purpose of this study will be to conduct a parametric investigation on the performance of elliptic airfoils for Rotor/Wing Unmanned Aerial Vehicles. The objective of this study is to conduct a two-dimensional, aerodynamic analysis on a various elliptic airfoil parameters, compare the reults of the analysis with theoretical predictions and experimental results, and evaluate handling and performance characteristics of Rotor/Wing UAVs during hover, transition, and forward flight"--Abstract, page iii.

Application Of Hybrid Arq To Controller Area Networks, Krishna Chaitanya Emani

Masters Theses

"This thesis proposes two types of Hybrid Automatic Repeat reQuest (HARQ) schemes for the Controller Area Network (CAN) to combat Electro-Magnetic Interference (EMI) and improve network efficiency. The proposed HARQ schemes encode the original CAN data frames by a Reed-Solomon (R-S) code so that burst errors due to EMI may be corrected at the receive nodes. Therefore, the probability of error frames is reduced, thereby reducing the probability of retransmission. Hence, the network efficiency of the system is improved"--Abstract, page iii.

Cfd Simulation Of Contact Planarization, Shanti Vusirikala

Masters Theses

"Semiconductor devices form the essential components of most electronic devices. The fabrication of circuit elements to manufacture these devices is done by a process known as photolithography, using photoresist layer deposition, optical masks, and etching. As feature sizes become smaller, higher optical precision is required, necessitating an optically flat surface on the photoresist layer. The surface of the photoresist layer can become uneven because of conformation to the topography of the layers underneath or a change in shape of the layer after evaporation of solvent. To combat this, Brewer Science, Inc. has developed a contact planarization process (CON-TACT®) in which …

Magnetohydrodynamic Power Generation In A Scramjet Using A Post Combustor Generator, Nathan Lee Mundis

Masters Theses

"A scramjet with a post combustor MHD generator is examined. A quasi-one-dimensional model is developed to calculate the flow path from tip to tail. The model includes losses due to combustion irreversibility, incomplete combustion, chemically reacting flow, friction, MHD losses, and nozzle plume modeling. Flight Mach number, magnetic field strength, gas conductivity, MHD load factor, and MHD generator expansion angle are all varied in order to assess their effects on MHD power generated and thrust lost in the engine. The trends produced through the above variations are summarized in a set of model-fit equations. It is concluded that a post …

Security Architecture Methodology For Large Net-Centric Systems, Njideka Adaku Umeh

Masters Theses

"This thesis describes an over-arching security architecture methodology for large network enabled systems that can be scaled down for smaller network centric operations such as present at the University of Missouri-Rolla. By leveraging the five elements of security policy & standards, security risk management, security auditing, security federation and security management, of the proposed security architecture and addressing the specific needs of UMR, the methodology was used to determine places of improvement for UMR"--Abstract, page iii.

A Software Defined Radio For Research Into Cognitive Radio, Jason Michael Pratt

Masters Theses

Software defined radios are capable of transmitting and receiving signals over a broad range of frequencies, and can alter their carrier frequency, modulation scheme, and power level by changing the software controlling the radio. Because of these capabilities, a software defined radio is the necessary platform for research into cognitive radio. The aim of cognitive radio is to more fully utilize the RF spectrum by allowing wireless communication systems to scan the spectrum for unused frequency bands and dynamically establish communication over one of those unused bands. This thesis gives a brief introduction into cognitive radio, and currently existing software …

Security Analysis Of A Cyber-Physical System, Han Tang

Masters Theses

"Cyber-Physical Systems (CPSs) are an integration of computing and physical processes. Information flow is an inherent property of CPSs and is of particular interest at their cyber-physical boundaries. This thesis focuses on discovering information flow properties and proposes a process to model the information flow in CPSs. A Cooperating FACTS Power System serves as a tangible example to illustrate modeling information flow using the proposed process. The proposed process can be used to model the information flow security, help analyze current information flow security requirements, and aid in the design of further security policies in CPS"--Abstract, page iii.

Use Of Analytical Hierarchy Process In University Strategy Planning, Mihir Gokhale

Masters Theses

"The selection of an appropriate strategy is critical for a university's success, and each university needs to capitalize on its own specialties and competencies for a competitive advantage. Strategy creation and planning in universities is generally a collective effort which relies on consensus. It is a complex process involving the setting of objectives and goals to achieve the strategic vision, and an analysis tool for evaluating and comparing different options and prioritizing objectives and goals is required. A high deductive capacity is necessary for aggregating the different trade-offs while prioritizing, which is challenging for a human mind. This thesis demonstrates …

Device Signal Detection Methods And Time Frequency Analysis, Narayana Ravirala

Masters Theses

"In this thesis the application of independent component analysis (ICA) to a multiple-source detection problem is studied. Specifically, a detection problem that is somewhat of a blend of the classical "signals with unknown parameters in noise" and "random signals in noise" problems is investigated. The idea is to detect the presence of a class of devices from their unintended radio frequency (RF) radiation. Because the signal is not an intended radiation, each device will emit a slightly different pattern. Moreover, these patterns may change under varying conditions such as battery voltage and ambient temperature. In addition, there may be several …

The Influence Of Printed Circuit Board Design On Tem Cell Measurements, Vijay Kasturi

Masters Theses

"The IEC 61967-2 integrated circuit radiated emissions test standard describes the use of the TEM cell to measure near-field emissions from an IC. This test requires a printed circuit board (PCB) to mount to IC. The IEC guidelines allow for flexibility in the design of this test PCB which may cause variations in the measured emissions. This thesis studies the impact of typical variations in the PCB design on the measured emissions"--Abstract, page iii.

Bridge Damage Detection Using An Intelligent Engineering System, Dionysios N. Danilatos

Masters Theses

"This thesis concerns the design of an algorithm that is capable to detect structural damage in civil infrastructure bridges. The algorithm, which will be dubbed Damage Diagnostics System throughout the thesis, is the software component of a broader Bridge Health Monitoring System. This broader system integrates software and hardware,such as sensors and data acquisition components...The rationale for the Structural Damage Diagnosis is based on the principle of the structural vibration testing. The Health Monitoring System captures the vibration signals, as the bridge responds to excitation from various sources. The purpose of the Diagnostic System is to extract information from the …

Modeling And Performance Estimation For Airborne Minefield Detection System, Saurabh Agarwal

Masters Theses

"Many programs aimed at airborne mine and minefield detection are being pursued and different algorithms are being developed and evaluated to achieve performance specifications. Thus far, no single algorithm or detection architecture has been able to fulfill the performance specifications for different mine and minefield detection scenarios...a need exists for a simulation based approach. One such simulation system is developed and evaluated in this thesis. The factors affecting the performance of an airborne detection system include physical parameters (type of background, time of day), data collection parameters (swath width, number of steps, in-step and in-flight overlap), and minefield scenarios. Data …

Friction Stir Processing Of Cast Magnesium Alloys, Timothy A. Freeney

Masters Theses

"This thesis investigates the feasibility and benefits of using friction stir processing as a thermo-mechanical microstructural modification tool for local property enhancement or casting repair of magnesium alloys, specifically high strength EV31A and WE43"--Abstract, page iv.

Analysis Of Soil Erosion Based On Soil Properties, Preetha Veeraraghavan

Masters Theses

"The objectives of this research were to identify the major soil parameter(s) that affect the erosion rate of soil and to estimate the erosion rate based on those soil parameters. Both prepared samples and natural samples were used in this research. The soil properties analyzed were the water content, unit weight, Atterberg limits, and soil cohesion. The erosion rate was determined using a rectangular flume and a linear relation between the erosion rate and shear stress was established from the flume experiment. The slope of the linear relation was a good indicator of the soil's erosion rate. The erosion rate …