Engineering Commons^™

Field And Laboratory Investigation Of Ozone-Indoor Surface Reactions: Secondary Emissions Inventory And Implications For Indoor Air Quality, Hong Wang

Doctoral Dissertations

"Interfacial chemistry greatly influences human exposure to reactants and products in indoor environments. Emissions of volatile organic compounds, as a result of ozone-surface interactions, can lower an occupant's exposure to ozone, but increase indoor concentrations of odorous and carcinogenic compounds. Therefore, investigation of ozone-surface interactions are necessary for better understanding and controlling exposure to ozone and the products of indoor surface chemistry. In this dissertation, field experiments were conducted in five homes in three seasons to quantify ozone-initiated secondary emission rates (SERs), yields surface reaction probabilities and study their temporal trends"--Abstract, page iv.

Innovative Solutions In Bridge Construction, Rehabilitation, And Structural Health Monitoring, Fabio Matta

Doctoral Dissertations

"This dissertation includes three technical papers that investigate the development of innovative technologies for bridge construction, rehabilitation, and structural health monitoring, respectively, at different stages of the technology transfer process...The research impact is twofold: first is the introduction of promising innovative technologies in development and implementation projects with the direct involvement of forward-thinking industry partners; second is the demonstration of the validity of these technologies on the basis of a rigorous scientific approach"--Abstract, page iv.

Enzymatic Synthesis And Characterization Of Oligopeptides, Co-Oligopeptides And Hydroxy Acid Capped Polypeptides In Mixed Aqueous Organic Media, Santhana Srinivasan

Doctoral Dissertations

"Proteolytic enzymes have been used for the synthesis of homo-oligomers and hydroxy acid capped peptides with amino acids and hydroxy acid esters as substrates in aqueous and aqueous organic biphasic and triphasic systems. However, successful incorporation of hydroxy acids in oligopeptide substrates has not been demonstrated. Use of monophasic media comprising of acetonitrile/water in which oligopeptide substrates were soluble was examined for the synthesis of oligomers of neutral and polar amino acids like Met, Tyr, Lys, Gly, Asp and Glu and tailored co-oligomers of Lys-Met and Arg-Met. Effect of reaction parameters such as starting substrate concentration, system composition, reaction time, …

Mechanical Integrity And Behavior Of Thin Films And Their Applications In Mems, Gang Duan

Doctoral Dissertations

"Electric actuated thin films are widely used in micro-electromechanical systems (MEMS) such as radio frequency switches (RF-switches), micro-pumps and valves, and electrostatic actuators. This dissertation will focus on the operation of a MEMS-RF-switch. In a typical MEMS-RF-switch, a mechanically suspended 1-D rectangular or 2-D axisymmetric thin film is pulled by an electrostatic voltage (V₀) applied to an electrode-pad directly underneath. When V₀ exceeds a certain "pull-in" threshold, V₀*, the thin film makes direct contact with the pad so that either an "on" or "off" signal is induced, and when the voltage is removed, the thin film resumes its original undeformed …

New Techniques To Improve Power Quality And Evaluate Stability In Modern All-Electric Naval Ship Power Systems, Peng Xiao

Doctoral Dissertations

"This dissertation focuses on two crucial issues in the design and analysis of the power electronic systems on modern all-electric naval ships, i.e., power quality control and stability evaluation. It includes three papers that deal with active power filter topology, active rectifier control, and impedance measurement techniques, respectively. To mitigate harmonic currents generated by high-power high-voltage shipboard loads such as propulsion motor drives, the first paper proposes a novel seven-level shunt active power filter topology, which utilizes tapped reactors for parallel operations of switching devices. The multi-level system has been implemented in both regular digital simulation and real-time digital simulator …

The Leaching Behavior Of Arsenic, Selenium And Other Trace Elements In Coal Fly Ash, Tian Wang

Doctoral Dissertations

"The goals of this study are four fold, they are: (1) to investigate the leaching behavior of arsenic and selenium from fly ash as well as their affecting factors; (2) to analyze the speciation of arsenic and selenium in fly ash leachate; (3) to develop a modeling approach to quantify the availability and stability of trace cationic elements in fly ash; (4) to apply this model to describe the leaching/adsorption behavior of arsenic and selenium on fly ash, as well as the calcium effect on arsenic (V) adsorption process"--Abstract, page iv.

Bga Footprints Modeling And Physics Based Via Models Validation For Power And Signal Integrity Applications, Giuseppe Selli

Doctoral Dissertations

"Modeling and simulating the multi-scale nature of a power distribution network (PDN) is essential to ensure the correct functioning of the devices connected to it. Simple parallel-plate sections constitute the core of these PDN geometries, together with sections where a large number of holes and vias are present, as in the case of a BGA footprint. Employing a divide-and-conquer approach allows for the modeling of these geometries separately, i.e., 3-D full wave solvers for the sections with holes and vias, and a cavity model approach, for the simple parallel-plate structures. Also, equivalent circuit models can be obtained for time-domain and …

Mobile Array Designs With Anserlin Antennas And Efficient, Wide-Band Peec Models For Interconnect And Power Distribution Network Analysis, Michael A. Cracraft

Doctoral Dissertations

"A mobile, wide-band antenna system has been developed around the ANSERLIN antenna element and a 3-dB splitter design. The size of the antenna elements was reduced over previous versions by introducing dielectric substrates. Additionally, new variations of the antenna were designed to influence radiation characteristics. To further reduce the number of components in the array, a very low profile splitter was designed and mounted below one of the antenna elements, doubling as the return plane for the antenna. The partial-element equivalent circuit (PEEC) method has been used for 3D interconnect analysis and numerous other applications. Being based on the same …

Modeling Network Traffic On A Global Network-Centric System With Artificial Neural Networks, Douglas K. Swift

Doctoral Dissertations

"This dissertation proposes a new methodology for modeling and predicting network traffic. It features an adaptive architecture based on artificial neural networks and is especially suited for large-scale, global, network-centric systems. Accurate characterization and prediction of network traffic is essential for network resource sizing and real-time network traffic management. As networks continue to increase in size and complexity, the task has become increasingly difficult and current methodology is not sufficiently adaptable or scaleable. Current methods model network traffic with express mathematical equations which are not easily maintained or adjusted. The accuracy of these models is based on detailed characterization of …

Experimental And Analytical Evaluation Of Frp-Confined Large Size Reinforced Concrete Columns, Silvia Rocca

Doctoral Dissertations

"Fiber Reinforced Polymer (FRP) jacketing of Reinforced Concrete (RC) columns, as a rapidly growing strengthening technique, requires appropriate design methods. However, the current available design guides are based on models, in their majority semi-empirical, and calibrated with small-scale plain concrete specimens. These models might not be reliable in predicting the strength and ductility enhancement sought through FRP-confinement in RC columns with geometric and material properties as found in practice. This dissertation presents the research conducted in three technical papers. In the first paper, the performance of 22 FRP-wrapped RC columns of medium- and large-scale is studied. The results of the …

Data Fusion Techniques For Health Monitoring Of Aging Aircraft And Skin Cancer Detection, Kapil Gupta

Doctoral Dissertations

"Data fusion is generally practiced to enhance decision or inference making capability. Sensor and information source data may often be corrupted by noise or other factors. Data fusion can be used to improve sensor and/or information source data quality and reliability and improve detection accuracy. There are several types of data fusion, including raw data level, feature level, and decision level.

This work presents the investigation and development of image and signal processing, computational intelligence, fuzzy logic, and statistical techniques for different types of data fusion for a varied range of applications. Raw data and decision level fusion approaches are …

Analysis Of The Holistic Impact Of The Hydrogen Economy On The Coal Industry, Shannon Perry Lusk

Doctoral Dissertations

"As gas prices soar and energy demand continues to grow amidst increasingly stringent environmental regulations and an assortment of global pressures, implementing alternative energy sources while considering their linked economic, environmental and societal impacts becomes a more pressing matter. The Hydrogen Economy has been proposed as an answer to meeting the increasing energy demand for electric power generation and transportation in an environmentally benign way. Based on current hydrogen technology development, the most practical feedstock to fuel the Hydrogen Economy may prove to be coal via hydrogen production at FutureGen plants. The planned growth of the currently conceived Hydrogen Economy …