Engineering Commons^™

Susceptibility Scanning System As Failure Analysis Tool For System Level Esd Problems, Giorgi Muchaidze

Masters Theses

"System level Electrostatic Discharges (ESDs) can lead to soft-errors (e.g., bit-errors, wrong resets). The goal of this project is to offer guidance in finding the root cause of soft-errors frequently observed using immunity scanning system. Immunity scanning is an increasingly adopted method for root cause analysis of system level immunity sensitivities. It allows localizing affected nets and ICs. At first a description of the ESD discharge process is given, which provides the necessary background for correctly analyzing ESD failures. Local scanning and in-circuit measurement techniques are expounded in this study. Further, it is shown how PCB scanning results can reveal …

Executable System Architecting Using Systems Modeling Language In Conjunction With Colored Petri Nets - A Demonstration Using The Geoss Network Centric System, Renzhong Wang

Masters Theses

"Models and simulation furnish abstractions to manage complexities allowing engineers to visualize the proposed system and to analyze and validate system behavior before constructing it. Unified Modeling Language (UML) and its systems engineering extension, Systems Modeling Language (SysML), provide a rich set of diagrams for systems specification. However, the lack of executable semantics of such notations limits the capability of analyzing and verifying defined specifications. This research has developed an executable system architecting framework based on SysML-CPN transformation, which introduces dynamic model analysis into SysML modeling by mapping SysML notations to Colored Petri Net (CPN), a graphical language for system …

The Importance And Influence Of Groundwater Fluctuations In Phytoremediation, Jeff A. Weishaar

Masters Theses

"The primary purpose of this research is to study the relationship between microbial degradation and plant uptake of volatile hydrocarbons, such as benzene, toluene, ethylbenzene and xylene. While these compounds are known to biodegrade and are capable of transport into plant tissue, any relationship between the two removal mechanisms remains largely unknown. The goal of this work is to better understand the interactions of these multiple biological processes within a phtytoremediation effort"--Introduction, page 3.

Characterization Of Coarse Aggregate Angularity Using Digital Image Processing, Gregory Allen Swift

Masters Theses

"This thesis involves a comparative analysis between well-established physically performed measurements for coarse aggregate and an image-based system. A thorough literature review was conducted, focusing on the importance of aggregate shape and how it is measured. In addition, state of the art in image-based aggregate measurement was reviewed along with the impacts and difficulties of an image-based methodology. Physical testing, consisting of Uncompacted Void Content, Index of Particle Shape and Texture (Compacted Voids), and Percent of Fractured Particles (fractured face or crush counts), was performed on aggregate control samples prior to testing on bulk aggregate samples. All aggregate samples were …

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.

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 …

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 …

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 …

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 …

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.

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. …

Synthesis And Characterization Of Platinum-Based Multi-Component Catalysts For Direct Methanol Fuel Cells, Li Ren

Masters Theses

"In the thesis work, Pt-based binary, ternary, quaternary alloy anode catalysts supported on sonochemically treated multi-walled carbon nanotubes (CNTs) were synthesized with ethylene glycol reduction of corresponding metal chloride salts. Inductively coupled plasma-mass spectroscopy (ICP-MS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) were used for catalyst characterization. Cyclic voltammetry for methanol oxidation and CO stripping were used to evaluate the performance of the catalysts.

PtRu nanoparticles supported on CNTs (PtRu/CNT) were prepared under a series of pHs. It was found that the PtRu particle size, composition, and catalytic activity were all sensitive to the deposition …

Neural Network Control Of Nonstrict Feedback And Nonaffine Nonlinear Discrete-Time Systems With Application To Engine Control, Jonathan B. Vance

Doctoral Dissertations

"In this dissertation, neural networks (NN) approximate unknown nonlinear functions in the system equations, unknown control inputs, and cost functions for two different classes of nonlinear discrete-time systems. Employing NN in closed-loop feedback systems requires that weight update algorithms be stable...Controllers are developed and applied to a nonlinear, discrete-time system of equations for a spark ignition engine model to reduce the cyclic dispersion of heat release"--Abstract, page iv.

Performance Improvement Of Adaptive Filters For Echo Cancellation Applications, Deepak Challa

Masters Theses

"This work focuses on performance improvement of adaptive algorithms for both line and acoustic echo cancellation applications. Echo in telephone networks, Line Echo, is observed naturally due to impedance mismatches at the long-distance/local-loop interface. Acoustic echo is due to the acoustic coupling between the microphone and the speaker of a speakerphone. The Affine Projection (APA) and the Fast Affine Projection (FAP) algorithms are two examples of reliable and efficient adaptive filters used for echo cancellation...This thesis presents, Variable Regularized Fast Affine Projections (VR-FAP) algorithm, with a varying, optimal regularization value which provides the desirable property of both fast and low …

A Computational Theory For The Generation Of Solutions During Early Conceptual Design, Cari R. Bryant

Doctoral Dissertations

"Advancement in technology is usually made by building on previous experiences and learning from past successes and failures. However, knowledge transfer in the broad field of product design is often difficult to accomplish. Research has shown that successful component configurations, observed from existing products, can be dissected and stored for reuse; but few computational tools exist to assist designers during the conceptual phase of design. Many well-known manual methods (e.g. brainstorming, intrinsic and extrinsic searches, and morphological analysis) rely heavily on individual bias and experience and are often time intensive, laborious tasks that may not catch solutions that are functionally …

Pilot Program To Assess Seismic Hazards Of The Granite City, Monks Mound, And Columbia Bottom Quadrangles, St. Louis Metropolitan Area, Missouri And Illinois, Deniz Karadeniz

Doctoral Dissertations

"Three 1:24000 scale quadrangles were selected for a pilot program intended to evaluate seismic site response across the spectrum of geologic conditions underlying the St. Louis Metropolitan area, using the Granite City, Monks Mound and Columbia Bottom quadrangles. These evaluations included assessments of: i) site amplification distributions; ii) probabilistic hazard analysis of PGA, 0.2 second and 1.0 second spectral accelerations for 2%, 5% and 10% probability of exceedance in 50 years; iii) two scenario earthquakes and their associated PGA, 0.2 sec, and 1 sec spectral accelerations; and v) sensitivity and uncertainty analyses. These hazard maps were prepared using a fully-probabilistic …

An Indirect Loss Estimation Methodology To Account For Regional Earthquake Damage To Highway Bridges, Chakkaphan Tirasirichai

Doctoral Dissertations

"This study proposes an integrated framework to estimate the indirect economic loss due to damaged bridges within the highway system from an earthquake event. The framework is designed to be general and convenient to apply to other study regions. In this dissertation, a simulated earthquake scenario centered in St. Louis Missouri with a magnitude 7.0 was used as a case study. The research results have clearly shown that the indirect losses are significant when compared to the direct loss. Policymakers can apply this study framework and the results as a guide and decision tool for developing an appropriate preventive action …

Artificial Immune System Based Algorithms For Optimization And Self-Tuning Control In Power Systems, Mani Hunjan

Masters Theses

"Artificial immune systems (AIS) are new computational intelligence methods inspired by various mechanisms of the biological immune system. AIS are adaptive systems inspired by theoretical immunology and its functions, principles and models. The work depicted in this thesis centers on the applications of AIS based algorithms for optimization and self-tuning control in power systems. The optimization is carried out using an algorithm based on the clonal selection principle and the self-tuning characteristics of control for parameters are inspired by the humoral immune response of the human body. The work in this thesis is written in two papers as follows: Paper …

Selective Laser Sintering Of Stearic Acid-Coated Alumina Ceramic, Jason J. Nolte

Masters Theses

"The purpose of this research is to develop a process that will enable a Selective Laser Sintering (SLS) machine to create geometrically complex green parts of various sizes that become strong, dense ceramic parts after sintering. This will be applicable to SLS systems already operational in industry, and may offer a more cost-effective, more time-efficient method for producing high-temperature ceramic rapid prototype parts. Alumina was the chosen ceramic for the developmental stage of this research. Fine alumina powder (average particle size of 0.4 µm) was coated with stearic acid, which served as a binder. Green parts were made from this …

Applications Of Solar Energy To Power Stand-Alone Area And Street Lighting, Joshua David Bollinger

Masters Theses

"A stand-alone solar-powered street or area lighting system is designed and operated completely independent of the power grid. The equipment and maintenance costs associated with a stand-alone solar-powered system are compared with the cost of using electricity to run grid connected street lights. The project focused on the viability of using solar energy to power the lights in the area surrounding St. Louis, Missouri. The results had to be consistent to warrant converting new areas to independent solar powered lighting. A prototype system is constructed from equipment available on the market for the purpose of gathering data on different lighting …

Compressor Valve Failure Detection And Prognostics, Raghuram Puthali Ramesh

Masters Theses

"Reciprocating compressors are commonly used machinery for industrial applications. Unscheduled downtime and maintenance activity on the compressors causes considerable loss in throughput and efficiency of a plant. Of all the failures that cause unscheduled downtime in reciprocating compressors, valve related causes are predominant. Most of the failures associated with the valves are tracked to the failure of moving elements within the valve. Achieving higher reliability of critical reciprocating systems requires continuously monitoring the system and performing dynamic analysis of the sensory data for valve fault diagnosis. Continuous monitoring will improve the time and cost to repair through keeping a constant …

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 …

Adhesion-Delamination Mechanics Of Linear And Axisymmetric Film At Film-Substrate Interface, Ming-Fung Wong

Masters Theses

"This thesis is to characterize the thin membrane adhesion-delamination phenomena which occur in biological cells and micro-electro-mechanical systems (MEMS) operation. The delamination of a thin film adhered to a rigid substrate is subjected to the coupling effects of tensile residual stress and interfacial adhesion energy. The adhesion-delamination mechanics is derived using the classical linear elasticity and thermodynamics energy balance. The membrane deformation is here dominated by a mixed plate-bending and membrane-stretching, while the concomitant stress is neglected. An 1-dimensional model is first investigated where a pre-stressed rectangular film clamped at both ends delaminates from a rigid punch of the same …

Manufacturing Of High Performance Composites Using Vacuum Assisted Resin Transfer Molding, V. G. K. Menta

Masters Theses

"The objective of this research is to establish and enhance the existing Vacuum Assisted Resin Transfer Molding (VARTM) process to manufacture high performance composite parts usable in the aerospace industry.

Flat, hat, pi and multi stiffened panels have been manufactured by the VARTM process using AS4-5HS and AS4-8HS carbon fabric, and SI-ZG-5A low viscosity epoxy resin. Silicone-based reusable molds have been designed and developed to manufacture stiffened panels. Dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) experiments of the SI-ZG-5A resin system were conducted to determine the storage modulus, loss modulus, and the glass transition temperature. The density and …

Damping Controllers For Power System Oscillations Using A Static Var Compensator, Sandhya R. Jetti

Masters Theses

"Damping of power system plays an important role in not only increasing the transmission capacity but also in stabilizing the power system, especially after critical faults. Static Var Compensator (SVC) is a shunt FACTS device which has capability of fast and continuous capacitive and inductive reactive power supply to the power system. SVCs are widely used for voltage stability but studies show that they are also effective in providing damping to the system. In this thesis, three types of SVC damping controllers are designed. The first damping controller is an optimal linear controller in which the parameters of a damping …

Design And Implementation Of A Hardened Distributed Network Endpoint Security System For Improving The Security Of Internet Protocol-Based Networks, William Dee Atkins

Masters Theses

"This thesis proposes a distributed approach to securing computer networks by delegating the role of a conventional firewall to a collection of nodes and controllers placed throughout the networks they are intended toprotect from attack. This distributed firewall system is a specific application of a generalized distriubted system framework that is also proposed in this thesis. The design and implementation of both the generalized framework and the application of the framework in creating a distributed firewall system for use on Ethernet-based networks that rely on the Internet Protocol are discussed. Conclusions based upon the preliminary implementation of the proposed systems …

Towards A Methodology For Integrated Freeform Manufacturing Systems Development With A Control Systems Emphasis, Jacquelyn K. Stroble

Masters Theses

"A variety of fully integrated Freeform Fabrication (FFF) systems have been developed, a selected group for research and several for commercialization. The design methodology behind most of them is not documented, standardized, or rational. It is important to understand that the final product from any integrated system is affected not only by the unit manufacturing processes themselves, but also by the extent the individual units are assimilated into an integrated process. Thus, a scheme consisting of eight steps and the salient five elements necessary to create or retrofit an existing system to achieve an Integrated Freeform Manufacturing System (FFMS) is …

Equivalent Circuit For Transient Conduction And Convection Systems, Bassam Sabry Mohammad Abdelnabi

Masters Theses

"Transient response of a natural convection system is investigated by numerical simulation using FLUENT code. An Integrator Circuit analogy was recently proposed for natural convection system. The proposed analogy was further confirmed by these recent simulations. New simulation results also suggest that a natural convection system acts as a "Low Pass" filter for transients. Transient transmission/attenuation factor was found to be a function of both fluid properties and the flow characteristics. Transmission/attenuation factor was also found to be a strong function of fluctuation frequency"--Abstract, page iv.

Age Strengthening Of Gray Cast Iron: Alloying Effects And Kinetics Study, Thottathil Viswanathan Anish

Masters Theses

"Age strengthening of gray cast iron has become a critical issue with metal casters trying to optimize their process for the closest conformance to properties. This necessitated more robust and precise methods to predict age strengthening. Most foundries use age strengthening behavior to cast at hight carbon equivalents to facilitate smaller gating systems. Also, it is well known in the casting industry that the tool life improves with aging. Hence these foundries require a model to predict aging behavior and accelerate the mechanism from days to hours. This research focuses on the methods of composition adjustments to control aging properties, …

Mechanical Properties And Microstructure Study For Direct Metal Deposition Of Titanium Alloy And Tool Steel, Yaxin Bao

Masters Theses

"This thesis is focused on the research about DMD (Direct Metal Deposition) which is an additive manufacturing process and used in various engineering applications such as producing fully dense and net shape productions in difficult-to-machine materials. In this study, the microstructure was analyzed through optical microscopy and some mechanical properties were tested with different equipments such as SEM (Scanning Electron Microscopy) and micro-hardness tester...In summary, this thesis validated that DMD process can be improved through surface treatments and is capable of repairing molds for die casting industry"--Introduction, page 1.