Digital Commons Network^™

Constraint Enforcement Methods For Command Governor Based Adaptive Control Of Uncertain Dynamical Systems, Simon P. Schatz, Tansel Yucelen, Eric N. Johnsony, Florian Holzapfelz

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Recently, research has been conducted in order to improve the transient behavior of adaptively controlled uncertain nonlinear dynamical systems. In this paper, an adaptive control architecture is extended in order to achieve predictable transient performance in the presence of state constraints. The methodology at hand is based on a robust command governor framework, which is a dynamical system adjusting the trajectory of a given command in order to track a certain desired closed-loop reference model both in transient time and steady-state. Specifically, the command, which is applied on the reference model and the actual system, is changed by the command …

The Rollamo 2013, Missouri University Of Science And Technology

Yearbooks

No abstract provided.

An Improved Dipole-Moment Model Based On Near-Field Scanning For Characterizing Near-Field Coupling And Far-Field Radiation From An Ic, Zhenwei Yu, Jason A. Mix, Soji Sajuyigbe, Kevin P. Slattery, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, an improved dipole-moment model for characterizing near-field coupling and far-field radiation from an IC based on near-field scanning is proposed. An array of electric and magnetic dipole moments is used to reproduce the field distributions in a scanning plane above an IC. These dipole moments can then be used as noise sources for the IC. In order to ensure the accurate prediction of the near-field coupling from the IC, the regularization technique and the truncated singular-value decomposition method are investigated in this paper, together with the conventional least-squares method, to reconstruct the dipole moments from the near-field …

A Wide-Band Equivalent Source Reconstruction Method Exploiting The Stoer-Bulirsch Algorithm With The Adaptive Frequency Sampling, P. Li, Y. Li, Lijun Jiang, J. Hu

Electrical and Computer Engineering Faculty Research & Creative Works

Conventional equivalent source reconstruction methods are only operating at a single frequency point each time. However, for wide-band radiators, their computation cost of the source reconstruction increases with the number of frequency points. In this communication, a wide-band equivalent source reconstruction method (WB-SRM) based on the Neville-type Stoer-Bulirsch (SB) algorithm is developed. Since the SB algorithm is a recursive tabular method, it can perform the interpolation over a broadband using a single rational function without any singularity issue. Supported by the adaptive frequency sampling (AFS) scheme, the number of required sampling data is significantly reduced, which leads to much better …

Emerging Technologies For Evolving Systems: Socio-Technical, Cyber And Big Data, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

No abstract provided.

Augmented Cognition In Human System Interaction Through Coupled Action Of Body Sensor Network And Agent Based Modeling, Siddhartha Agarwal, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

This research proposes a conceptual model to make significant progress in augmented cognition. We intend to design a generic architecture to improve the collective situational awareness (SA) of a team of soldiers on the battlefield during combat effects, and cultural communications. It also establishes a training outline for future landscapes of a similar nature by providing convincing feedback. It will serve as architecture of a model, based on the current laboratory framework. This involves data analysis of the feedback from the neurophysiological body sensors (heart rate, skin temperature, breathing rate and others) placed on a wearable immersive training vest. It …

Design And Analysis Of An Open-Ended Waveguide Probe For Material Characterization, Matthew Alan Kempin

Masters Theses

"Nondestructive evaluation of stratified (layered) composite structures at microwave and millimeter wave frequencies is of great interest in many applications where simultaneous determination of the complex dielectric properties and thicknesses of multiple layers is desired. Open-ended rectangular waveguide probes are effective tools for this purpose. The technique requires a full-wave electromagnetic model that accurately calculates the complex reflection coefficient as a function of frequency and material properties. Subsequently, this information is used in conjunction with the measured complex reflection coefficient to evaluate the sought for material properties. This thesis presents simulated and measured data to investigate the influence that measurement …

Processing And Properties Of Zrb₂-Zrsi₂ Matrix Composites Reinforced With Continuous Sic Fiber, Benjamin John Bowin Lai

Masters Theses

"The research presented in this thesis focuses on the processing, microstructure, and mechanical properties of ZrB₂-based composites. The main goal was to develop a process that incorporates high strength continuous SiC fiber in a ZrB₂-based matrix. In order to achieve this, the densification, microstructure, and mechanical properties of ZrB₂-ZrSi₂ monolithic ceramics were characterized along with various SiC fiber reinforced ceramic matrix composites (CMCs) utilizing the same matrix.

There were two main areas of study in this thesis. The initial study demonstrated that additions of ZrSi₂ into a ZrB₂ ceramic increases densification at significantly reduced processing temperatures ≤1600ºC). This study revealed …

Common Mode Current Estimation For Cable Bundle Inside A Vehicle, Dazhao Liu

Doctoral Dissertations

"In the Section 1, it introduces a methodology to simulate the currents and fields during an air discharge ESD into a product by combining a linear description of the behavior of the DUT with a non-linear arc resistance equation. The most commonly used test standard IEC 61000-4-2 requires using contact mode discharges to metallic surfaces and air discharge mode to non-conducting surfaces. This paper proposes a method that combines the linear ESD generator full wave model and the non-linear arc model to simulate currents and fields in air discharge mode. In Section 2, when simulating surface and thin wire structures, …

Characterization Of Nano-Scaled Metal-Hydrides Confined In Nano-Porous Carbon Frameworks, David Edward Peaslee

Doctoral Dissertations

"Metal hydrides are currently being studied to provide hydrogen for use in fuel cells and for transportation applications. Hydrogen can be stored in chemical compounds at higher density and lower volume than liquid H₂ or compressed gas. Thermodynamic properties of metal hydrides differ between bulk and nano-sized particles. Many metal hydrides with useful volumetric and gravimetric capacities have high decomposition temperatures, but when placed in nano-sized frameworks (or templates) desorption and adsorption temperatures can be fine-tuned to meet engineering requirements for real-world systems. Additionally, some metal hydrides have shown a change in the decomposition pathway when infiltrated into these frameworks, …

Privacy-Preserving Friend Recommendations In Online Social Networks, Bharath Kumar Samanthula

Doctoral Dissertations

"Online social networks, such as Facebook and Google+, have been emerging as a new communication service for users to stay in touch and share information with family members and friends over the Internet. Since the users are generating huge amounts of data on social network sites, an interesting question is how to mine this enormous amount of data to retrieve useful information. Along this direction, social network analysis has emerged as an important tool for many business intelligence applications such as identifying potential customers and promoting items based on their interests. In particular, since users are often interested to make …

Analysis Of Model Uncertainty In Hydraulic Modeling: The Bstem Application To The Osage River, Annabell Leigh Ulary

Masters Theses

"Uncertainty is inevitable when creating any kind of model. A model can be used in the most accurate way possible, if the uncertainties are understood. This study determines the level of uncertainty in the Bank Stability and Toe Erosion Model (BSTEM) of the Osage River downstream of Bagnell Dam between Lake Ozark, MO and Jefferson City, MO. The statistical analysis of the BSTEM model was performed using the aid of SAS statistical computer modeling software. There were 4 different analysis values used to determine the best fit model for all dependent variables. These values include the F-test, the coefficient of …

Paste Development And Co-Sintering Test Of Zirconium Carbide And Tungsten In Freeze-Form Extrusion Fabrication, Ang Li

Masters Theses

"Ultra-high temperature ceramics are being investigated for future use in aerospace applications due to their superior thermo-mechanical properties, as well as oxidation resistance, at temperatures above 2000°C. However, their brittle properties make them susceptible to thermal shock failure. Components fabricated as functionally graded materials (FGMs) can combine the superior properties of ceramics with the toughness of an underlying refractory metal by fabricating graded composites. This paper discusses the grading of two materials through the use of a Freeze-form Extrusion Fabrication (FEF) system to build FGMs parts consisting of zirconium carbide (ZrC) and tungsten (W). Aqueous-based colloidal suspensions of ZrC and …

Development Of A Methodology For Pseudo-Rigid-Body Models Of Compliant Segments With Inserts, And Experimental Validation, Raghvendra Sharadchandra Kuber

Masters Theses

"Compliant mechanisms have shown a great deal of potential in the last few decades in providing better solutions to design problems with numerous benefits; however, their use has been limited due to current challenges in the material selection. With ever increasing focus on the applications of compliant mechanisms, it is necessary to find alternatives to the existing materials and methods of prototyping. The purpose of this work is to develop a methodology for pseudo-rigid-body models of compliant segments with compliant inserts, comprised of a resilient material placed between the layers of a softer material, to alleviate any creep and strength …

Comparison Of Class Ii Injection Well Area Of Review Requirements With Area Of Evaluation For Hydraulically Fractured Wells, Yashesh Jitendra Panchal

Masters Theses

"Since 2010 the US Environmental Protection Agency (EPA) has been proposing plans to study, and has now initiated research regarding the potential impact of hydraulic fracturing processes on drinking water sources. Their work refers to an 'Area of Evaluation' around a hydraulically fractured well, inferring that the wells immediately around hydraulic fractured wells should be studied, to evaluate the conditions of these wells and their potential to contaminate overlying USDWs. Class II injection wells must have a minimum 1/4 mile radius area of review to determine the condition of wells surrounding the proposed injection well. All wells within this AOR …

Comparative Evaluation Of N-Acetylcysteine And N-Acetylcysteine Amide In Acetaminophen-Induced Oxidative Stress, Ahdab Naeem Khayyat

Masters Theses

"Acetaminophen (APAP) is the most widely used pharmaceutical analgesic-antipyretic agent in the world, but its toxicity is a common cause of drug-induced hepatotoxicity. With APAP toxicity, cellular glutathione (GSH) is depleted. This results in the availability of N-acetyl-p-benzoquinone imine (NAPQI), is a toxic metabolite of APAP that binds to cellular macromolecules, which leads to cell necrosis. N-acetyl cysteine (NAC), a GSH precursor, is the only approved antidote for an acetaminophen overdose. It is a negatively charged molecule that diminishes its penetration into the cells, thereby requiring fairly high doses that increase the severity of side effects. In addition, oral and …

Parallel-Connected Solar Arrays, Majed Meshal Alabbass

Masters Theses

"The purpose of this thesis is to investigate the advantages of having various series-parallel configurations of solar arrays and make a comparison between them. The objective is to determine the best PV system configuration and thus improve the overall efficiency of a solar array. The primary focus of this thesis is to study the parallel connection of PV panels for achieving maximum efficiency while extracting maximum energy from the solar radiation. A comparison between a series connected and a parallel connected solar PV array justifies the need for installing a parallel configured solar PV array to achieve optimum performance. The …

Assessment Of An Enterprise Employee Portal Using Dashboard Monitoring System: A Case Study, Aditi Mishra

Masters Theses

"A portal is a browser-based application that provides a web platform for users to improve inter-department collaboration and customer service. Portals are classified either as internal facing portals or external public facing portals. This study addresses the problems facing an internal portal related to its contents, functions and usability and provides a list of essential contents and functions that it should include through integrating theories and industry best practices. The theory framework is based on literature review and the industry best practices are based on the analysis of a number of internal portals of companies used as case studies. These …

Transmission Shaft Design For Hydrokinetic Turbine With Reliability Consideration, Goutham Pusapati

Masters Theses

"Hydrokinetic energy, a relatively new kind of renewable energy, can be generated from flowing water in rivers or oceans. Hydrokinetic turbines (HKTs) are a major system for hydrokinetic energy, and the reliability of the HKTs is critical for both their lifecycle cost and safety. The objective of this work is to apply advanced methodologies of reliability analysis and reliability-based design to the transmission shaft design for a horizontal-axis, non-submerged HKT. The deterministic shaft design is performed first by considering failure modes of strength and deflection using distortion energy, maximum shear and deflection theories. Then the reliability analysis of the shaft …

Shopping Alone Online Vs. Co-Browsing: A Physiological And Perceptual Comparison, Ceren Topaloglu

Masters Theses

"Although shopping is a social activity frequently performed with friends and family members, most online shopping is done alone. With the development of Web 2.0 technologies and the increasing popularity of social networking sites, online social shopping has emerged as a new phenomenon that allows more social interaction, participation, and satisfaction for customers while shopping online. Therefore, companies have started to use social shopping tools in their e-commerce websites to facilitate online social shopping. Co-browsing is one of the more recent online social shopping tools available, enabling users to shop or browse together by offering synchronized web views and chat …

Water Management Capabilities Of Bio-Inspired Flow Field Configurations For Polymer Electrolyte Membrane Fuel Cells, Nicholas Warren Freer

Masters Theses

"Fuel cells have received an increasing amount of attention over the past decade for their power production capabilities. Polymer electrolyte membrane (PEM) fuel cells in particular are researched because of their high power density, large range of operating conditions, green products, and ease of scalability. PEM fuel cells do have a number of issues that reduce their overall performance. These issues include variations in reactant distribution, materials issues for the bipolar plate, and flooding caused by poor water management. Variations in the reactant distribution causes lower overall power output due to regions of low reactant density. This means that optimizing …

Green Roof Water Quality Impacts And Physicochemical Stability, Grace Ella Harper

Masters Theses

"Green roofs can provide environmental benefits and conserve energy; this research evaluated green roof stormwater management, nutrient loading, and erosion prevention for two green roof media. During a pilot study, the runoff quantity and composition from green roof material was evaluated continuously under field conditions for two different media, both tested under planted and unplanted conditions. Water quantity results show over a 40% reduction in runoff from just the growing media and over 60% reduction in runoff with established plants in green roof media over the eight month study. Previous studies have reported a "first flush" of excess nutrients but …

Part Height Control Of Laser Metal Additive Manufacturing Process, Yu-Herng Pan

Masters Theses

"Laser Metal Deposition (LMD) has been used to not only make but also repair damaged parts in a layer-by-layer fashion. Parts made in this manner may produce less waste than those made through conventional machining processes. However, a common issue of LMD involves controlling the deposition's layer thickness. Accuracy is important, and as it increases, both the time required to produce the part and the material wasted during the material removal process (e.g., milling, lathe) decrease. The deposition rate is affected by multiple parameters, such as the powder feed rate, laser input power, axis feed rate, material type, and part …

Wetting And Drying Cycles And The Fungal Communities On Leaf Litter In Streams, Kele Qwinn Thrailkill

Masters Theses

"Leaf litter is a major source of energy for streams in deciduous forests. Fungi play a critical role by converting the leaves into nutritional material for the rest of the food web. The breakdown of leaf litter and associated biota, including invertebrates and fungi, have been proposed as measures of stream health in systems affected by anthropogenic activity. Rates of leaf breakdown can be depressed in streams affected by acidity, metals, organic contaminants, and other stressors. Climate change may lead to alterations in stream hydrology such that streams experience more frequent floods as well as drying episodes. Fungal communities can …

Direct Shear Transfer Of Lightweight Aggregate Concretes With Non-Monolithic Interface Conditions, Dane Michael Shaw

Masters Theses

"This thesis describes the results of a study initiated to examine the influence of concrete unit weight on the direct shear transfer across an interface of concretes cast at different times. This type of interface is common with structural precast concrete connections, such as corbels, for which shear friction design provisions are commonly used. Increasing use of lightweight aggregate concretes prompted this investigation to determine the appropriateness of current shear friction design provisions with respect to all-lightweight and sand-lightweight concrete. The experimental investigation included thirty-six push-off test specimens, each of which was constructed with a cold-joint at the interface shear …

Examining The Efficiency Of Multimodal Transportation Systems: A Systems Dynamics Approach, Lizzette Pérez-Lespier

Masters Theses

"With international trade becoming a big part of the world's economic activity, the demand for good freight transportation systems has grown substantially. The appropriate use of transportation is an integral part of the supply chain's effectiveness. Therefore, the continuous economic globalization, the growing demand for speed-to-market product delivery, and the need to manage global supply chains more effectively, has led to the sustained increase in demand towards multimodal transportation systems (MTS). MTS play an essential role in corporations competing in global markets in the 21st century. In transportation, the effectiveness and efficiency of the whole system depends upon the interconnectivity …

Design, Construction And Load Testing Of The Pat Daly Road Bridge In Washington County, Mo, With Internal Glass Fiber Reinforced Polymers Reinforcement, Zhibin Lin, Mostafa Fakharifar, Chenglin Wu, Genda Chen, Wesley James Bevans, Arun Vijay Kumar Gunasekaran, Sahra Sedigh

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The overarching goal of this project is to deploy and assess an innovative corrosion-free bridge construction technology for long-term performance of new and existing bridges. The research objective of this project is to conduct a comprehensive study (instrumentation, construction, both laboratory and field evaluation) of a rapidly constructed and durable, three-span bridge with cast-in-place cladding steel reinforced concrete substructure and precast concrete decks/girders reinforced with glass fiber reinforced polymers (GFRP). The bridge has one conventional concrete-girder span, one conventional steel-girder span, and one innovative concrete box-girder span. The conventional concrete and steel girders were used to demonstrate the effective use …

Rapid Repair Of Severely Damaged Rc Columns With Different Damage Conditions: An Experimental Study, Ruili He, Lesley Sneed, Abdeldjelil Belarbi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Review Of Anchorage Systems For Externally Bonded Frp Laminates, Stephen V. Grelle, Lesley Sneed

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Aggregate Shape Characterization Using Digital Image Processing, Norbert H. Maerz, David Newton Richardson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Aggregates must meet certain specifications to be acceptable in asphalt and concrete applications. Among these are specifications that deal with the various aspects of aggregate shape, including flatness and elongation and aggregate angularity. The current practice for ensuring those specifications is the use of manual-mechanical tests. These tests are time consuming, labor intensive and subjective. In addition, tests such as the compacted or uncompacted voids tests (Figure 1), are taken to be a shape (angularity) indicator, even thought the measured quantify is the void ratio. This report describes a prototype of an automated digital video image analysis system that measures …