Engineering Commons^™

Management Of Target-Tracking Sensor Networks, Khaled Hadi

Open Access Dissertations

Target tracking has emerged as an important application of sensor networks. There are two subproblems inherent to target tracking. The first is the initial location of the target as it enters the region being covered. The second is following its track once it has been discovered. In this work, we outline an approach to target tracking. We present an energy-aware tracking algorithm that predicts the target track and activates nodes based on that prediction. We then discuss different energy management schemes that resolve tradeoffs between energy savings and track quality for a specified mission lifetime. Our energy management schemes perform …

Application Of Driver Behavior And Comprehension To Dilemma Zone Definition And Evaluation, David S. Hurwitz

Open Access Dissertations

Among the most critical elements at signalized intersections are the design of vehicle detection equipment and the timing of change and clearance intervals. Improperly timed clearance intervals or improperly placed detection equipment can potentially place drivers in a Type I dilemma zone, where approaching motorists can neither proceed through the intersection before opposing traffic is released nor safely stop in advance of the stop bar. Type II dilemma zones are not necessarily tied to failures in design, but are more readily tied to difficulties in driver decision making associated with comprehension and behavior. The Type II dilemma zone issues become …

Synthesis And Study Of Hybrid Organic – Inorganic Polyhedral Oligomeric Silsesquioxanes (Poss) Based Polymers, Gunjan A, Gadodia

Open Access Dissertations

Hybrid organic-inorganic materials represent a new class of materials having scientific and technological potential. In this thesis, Polyhedral Oligomeric Silsesquioxanes (POSS) are used as an inorganic building block which has been tethered to an organic polymer. POSS are silica precusors, having a well defined silsesquioxane cental core surrounded by an organic periphery which makes them compatible with monomers and possibly polymers. The objectives of this study are to (1) study the basic structures of POSS homopolymers, (2) to incorporate POSS building blocks by a bottomup approach into polymer chains and study the resulting morphologies, and (3) to study the thin …

Mechanics Of Hydrogels And Biological Tissues, Jessica A. Zimberlin

Open Access Dissertations

The relationship between cells and their environment is one of dynamic reciprocity, whereby cells can influence their surrounding and the surroundings can influence the cells. One example of this relationship arises from the effect of the mechanical properties of an environment on a cell and of a cell on its environment. Inspired by this relationship, we investigate 1) the local environment of biological materials, both native and synthetic, and 2) the forces that cell sheets exert on surfaces. We do this by developing techniques that focus on local mechanical properties and experimental strategies that provide insight into intercellular mechanics. We …

Muscular Properties And Balance Control In Older Adults, Christopher James Hasson

Open Access Dissertations

The goal of this dissertation was to understand the role of age-related changes in muscle mechanical properties in the control of upright posture in humans. First, a methodology for estimating subject-specific muscle properties in healthy young and older individuals was developed. Magnetic resonance and ultrasound imaging were used in conjunction with dynamometer experiments, musculoskeletal modeling, and numerical optimization to estimate the properties of the dorsiflexor and individual plantarflexor (gastrocnemius and soleus) muscles for 12 young and 12 older adults (balanced for gender). With aging there were declines in maximal isometric strength and increases in series-elastic stiffness in the male subjects, …

Nanofabrication Techniques For Nanophotonics, Ozgur Yavuzcetin

Open Access Dissertations

This thesis reports the fabrication of nanophotonic structures by using electron beam lithography and using pattern transfer via self assembly with the aid of block copolymers. A theoretical and experimental basis was developed for fabricating anti-reflective coatings using block-copolymer pattern transfer. Block-copolymers were also used to fabricate plasmonic pattern arrays which form gold dots on glass surface. Electron-beam lithography was utilized to fabricate holey plasmonic structures from gold and silver films. Electron-beam exposure was used in block-copolymer lithography in selected regions. The exposure effects were studied for both thin and thick block-copolymer films. Reactive and ion beam etching techniques were …

Atomic-Scale Analysis Of Plastic Deformation In Thin-Film Forms Of Electronic Materials, Kedarnath Kolluri

Open Access Dissertations

Nanometer-scale-thick films of metals and semiconductor heterostructures are used increasingly in modern technologies, from microelectronics to various areas of nanofabrication. Processing of such ultrathin-film materials generates structural defects, including voids and cracks, and may induce structural transformations. Furthermore, the mechanical behavior of these small-volume structures is very different from that of bulk materials. Improvement of the reliability, functionality, and performance of nano-scale devices requires a fundamental understanding of the atomistic mechanisms that govern the thin-film response to mechanical loading in order to establish links between the films' structural evolution and their mechanical behavior. Toward this end, a significant part of …

Developing Reactive Molecular Dynamics For Understanding Polymer Chemical Kinetics, Kenneth D. Smith

Open Access Dissertations

One of the challenges in understanding polymer flammability is the lack of information about microscopic events that lead to macroscopically observed species, and Reactive Molecular Dynamics is a promising approach to obtain this crucially needed information. The development of a predictive method for condensed-phase reaction kinetics can provide significant insight into polymer ammability, thus helping guide future synthesis of fire-resistant polymers. Through this dissertation, a new reactive forcefield, RMDff, and Reactive Molecular Dynamics program, RxnMD, have been developed and used to simulate such material chemistry. It is necessary to have accurate description of chemical kinetics to describe quantitative chemical kinetics. …

Oligopeptide-Functionalized Graft Copolymers: Synthesis And Applications In Nucleic Acid Delivery, Rebecca Boudreaux Breitenkamp

Open Access Dissertations

Utilizing the diverse functionality of amino acids, a new class of amphiphilic graft copolymers has been synthesized, characterized, and explored for applications in biomaterials and nucleic acid delivery. This thesis research focused on the syntheses of oligopeptide-functionalized polyesters and polyolefins. Polyester functionalization was geared towards applications in biomaterials, tissue engineering, and drug delivery by incorporating sequences that promote cell-adhesion. These polyester- graft -oligopeptide materials were prepared by a 1,3-Huisgen cycloaddition reaction, "click" chemistry, of an azide-terminated oligopeptide (prepared by Fmoc-based solid phase peptide synthesis (SPPS)) and alkyne-containing polyester (synthesized by ring-opening polymerization). Following the syntheses of these materials, they were …

Polymer Confinement And Translocation, Chiu Tai Andrew Wong

Open Access Dissertations

Single polymer passage through geometrically confined regions is ubiquitous in biology. Recent technological advances have made the direct study of its dynamics possible. We studied the capture of DNA molecules by the electroosmotic flow of a nanopore induced by its surface charge under an applied electric field. We showed theoretically that the DNA molecules underwent coil-stretch transitions at a critical radius around the nanopore and the transition assisted the polymer passage through the pore. To understand how a polymer worms through a narrow channel, we investigated the translocation dynamics of a Gaussian chain between two compartments connected with a cylindrical …

Synthesis And Interfacial Behavior Of Functional Amphiphilic Graft Copolymers Prepared By Ring-Opening Metathesis Polymerization, Kurt E. Breitenkamp

Open Access Dissertations

This thesis describes the synthesis and application of a new series of amphiphilic graft copolymers with a hydrophobic polyolefin backbone and pendent hydrophilic poly(ethylene glycol) (PEG) grafts. These copolymers are synthesized by ruthenium benzylidene-catalyzed ring-opening metathesis polymerization (ROMP) of PEG-functionalized cyclic olefin macromonomers to afford polycyclooctene- graft -PEG (PCOE- g -PEG) copolymers with a number of tunable features, such as PEG graft density and length, crystallinity, and amphiphilicity. Macromonomers of this type were prepared first by coupling chemistry using commercially available PEG monomethyl ether derivatives and a carboxylic acid-functionalized cycloctene. In a second approach, macromonomers possessing a variety of PEG …

Effect Of Loading And Process Conditions On The Mechanical Behavior In Sebs Thermoplastic Elastomers (Tpes), Mohit Mamodia

Open Access Dissertations

Styrenic block copolymer thermoplastic elastomers are one of the most widely used thermoplastic elastomers (TPEs) today. The focus of this research is to fundamentally understand the structure-processs-property relationships in these materials. Deformation behavior of the block copolymers with cylindrical and lamellar morphologies has been investigated in detail using unique techniques like deformation calorimetry, transmission electron microscopy (TEM), combined in-situ small angle x-ray and wide angle x-ray scattering (SAXS/WAXS). The research involves the study of structural changes that occur at different length scales along with the energetics involved upon deformation. The structural changes in the morphology of these systems on deformation …

"Hedging Future Uncertainty: A Framework For Obsolescence Prediction, Proactive Mitigation And Management", Craig L Josias

Doctoral Dissertations 1896 - February 2014

Component obsolescence in the "high-tech" electronics industry has become a problem that cannot be ignored. Although recent attention has been given to component obsolescence, in general this issue is still dealt with reactively. This often results in sustainment of a long-life system such as ships, airplanes, power plant, and space based programs to be extremely costly. In addition, delayed schedules, extended downtimes, and technology lags are common occurrences in approaches that deal with obsolescence as it occurs. In wake of the rapid pace of technology innovation, turbulent markets and growing globalization, developing proactive approaches for dealing with obsolescence is a …

Supercritical Fluid Deposition Of Thin Metal Films: Kinetics, Mechanics And Applications, Christos Fotios Karanikas

Doctoral Dissertations 1896 - February 2014

In order to meet the demands of the continuous scaling of electronic devices, new technologies have been developed over the years. As we approach the newest levels of miniaturization, current technologies, such as physical vapor deposition and chemical vapor deposition, are reaching a limitation in their ability to successfully fabricate nano sized electronic devices.

Supercritical fluid deposition (SFD) is a demonstrated technology that provides excellent step coverage for the deposition of metals and metal oxides within narrow, high aspect ratio features. This technique shows the potential to satisfy the demands of integrated circuit miniaturization while maintaining a cost effective process …

Understanding Adsorption In Mesoporous Materials Through Lattice-Based Density Functional Theory And Monte Carlo Simulation, Bradd E Libby

Doctoral Dissertations 1896 - February 2014

Confining walls induce qualitative changes in adsorbed fluids. Among the most intriguing phenomena is hysteresis, where a pore fills with fluid at a greater pressure than it empties. The causes and mechanisms by which this occurs are intensely investigated yet still poorly understood. Ordered mesoporous silicas, recently discovered materials with well-defined pore size distributions, provide an opportunity to deepen our understanding of the fundamental physics of the interaction of fluids with complex solids.

In part of this computational investigation we examine idealized pores. In agreement with other recent studies, we find that in 'inkbottle'-shaped pores, where a large cavity is …

Investments In Energy Technological Change Under Uncertainty, Ekundayo Shittu

Doctoral Dissertations 1896 - February 2014

This dissertation addresses the crucial problem of how environmental policy uncertainty influences investments in energy technological change. The rising level of carbon emissions due to increasing global energy consumption calls for policy shift. In order to stem the negative consequences on the climate, policymakers are concerned with carving an optimal regulation that will encourage technology investments. However, decision makers are facing uncertainties surrounding future environmental policy. The first part considers the treatment of technological change in theoretical models.

This part has two purposes: (1) to show-through illustrative examples-that technological change can lead to quite different, and surprising, impacts on the …

Microwave Reactor Engineering Of Zeolites Synthesis, Murad Gharibeh

Doctoral Dissertations 1896 - February 2014

Microwave chemistry has expanded over the last two decades due to the enhanced reaction rates achieved for many processes, including organic synthesis, inorganic synthesis and polymerization. Significant time and energy saving can be realized using microwave chemistry, which is important both commercially and for the environment.

One of the most exciting and commercially/technologically significant areas where microwave energy has been demonstrated to influence the kinetics and selectivity is in the synthesis of nanoporous materials, such as zeolites. New nanoporous materials can be created, and the times for their syntheses can be significantly reduced, involving using less energy. By reducing the …

Functionalized Nanoparticles For Biological Imaging And Detection Applications, Bing C Mei

Doctoral Dissertations 1896 - February 2014

Semiconductor quantum dots (QDs) and gold nanoparticles (AuNPs) have gained tremendous attention in the last decade as a result of their size-dependent spectroscopic properties. These nanoparticles have been a subject of intense study to bridge the gap between macroscopic and atomic behavior, as well as to generate new materials for novel applications in therapeutics, biological sensing, light emitting devices, microelectronics, lasers, and solar cells. One of the most promising areas for the use of these nanoparticles is in biotechnology, where their size-dependent optical properties are harnessed for imaging and sensing applications. However, these nanoparticles, as synthesized, are often not stable …

Fault-Tolerant Nanoscale Microprocessor Design On Semiconductor Nanowire Grids, Teng Wang

Doctoral Dissertations 1896 - February 2014

As CMOS manufacturing technology approaches fundamental limits, researchers are looking for revolutionary technologies beyond the end of the CMOS roadmap. Recent progress on devices, nano-manufacturing, and assembling of nanoscale structures is driving researchers to explore possible new fabrics, circuits and architectures based on nanoscale devices.

Several fabric architectures based on various nanoscale devices have been proposed for nanoscale computation. These show great advantages over conventional CMOS technology but focus on FPGA-style applications. There has been no work shown for nanoscale architectures tuned for a processor application.

This dissertation proposes a novel nanowire-based 2-D fabric referred to as Nanoscale Application-Specific IC …