Digital Commons Network^™

Biomimetic Synthesis Within Polyelectrolyte Microcapsules: Characterization Of Enzyme Catalyzed Polyphenols And Polypeptides, Rohit C. Ghan

Doctoral Dissertations

An enzyme-catalyzed synthesis of novel polymers within layer-by-layer (LbL) constructed polyelectrolyte microcapsules has been developed. This approach is based on the selective permeability of polyelectrolyte-capsule walls to monomer molecules. Conversely biocatalysts and forming polymeric chains cannot exit the micro-capsule interior because of their characteristic high molecular weight. Horseradish Peroxidase (HRP) was encapsulated into four bilayer PSS (poly-styrenesulfonate)/PAH (poly-allylamine hydrochloride) capsules with an average diameter of 5 μm using pH-driven pore opening. The polymerization of 4-(2-Aminoethyl) phenol hydrochloride (tyramine) catalyzed by HRP produces easily detectable fluorescent polymeric products after the addition of hydrogen peroxide to the system. It is known that …

Computational Approaches To The Design And Analysis Of Stability Of Polypeptide Multilayer Thin Films, Bin Zheng

Doctoral Dissertations

The focus of this research is the development of computational approaches to understanding the physical basis of layer-by-layer assembly (LBL), a key methodology of nanomanufacturing. The results provided detailed information on structure which cannot be obtained directly by experiments.

The model systems chosen for study are polypeptide chains. Reasons for this are that polypeptides are no less polyelectrolytes than the more usual polyions, and one can control the primary structure of a polypeptide on a residue-by-residue basis using modern synthetic methods. Moreover, as peptides constitute one of the four major classes of biological macromolecules, research in this direction is expected …

Sense -Based Text Classification By Semantic Hierarchy Representation, Xiaogang Peng

Doctoral Dissertations

Automatic classification of web pages is an effective way to facilitate the process of retrieving information from the Internet. Currently, two major classification methods are used in this area: keyword-based classification and sense-based classification. For keyword-based classification, keywords often have different semantic meanings, and the correct keyword matching is largely based on using exactly the same keywords. Thus, the classification results of keyword-based classification are not always satisfying. Many sense-based classification algorithms and systems have been presented, but they pay little attention to the relationship between senses. In this dissertation, we present a method to automatically classify documents based on …

Fabrication, Characterization, And Modeling Of Organic Capacitors, Schottky Diodes, And Field Effect Transistors, Mo Zhu

Doctoral Dissertations

The objectives of this project are to fabricate, characterize, and model organic microelectronic devices by traditional lithography techniques and Technology Computer Aided Design (TCAD).

Organic microelectronics is becoming a promising field due to its number of advantages in low-cost fabrication for large area substrates. There have been growing studies in organic electronics and optoelectronics. In this project, several organic microelectronic devices are studied with the aid of experimentation and numerical modeling.

Organic metal-insulator-metal (MIM) and metal-insulator-semiconductor (MIS) capacitors consisting of insulating polymer poly(4-vinylphenol) (PVP) have been fabricated by spin-coating, photo lithography, and reactive ion etching techniques. Based on the fabricated …

A High -Order Finite Difference Method For Solving Bioheat Transfer Equations In Three-Dimensional Triple -Layered Skin Structure, Haofeng Yu

Doctoral Dissertations

Investigations on instantaneous skin burns are useful for an accurate assessment of burn-evaluation and for establishing thermal protections for various purposes. Meanwhile, hyperthermia with radiation is important in the treatment of cancer, and it is essential for developers and users of hyperthermia systems to predict, and interpret correctly the biomass thermal and vascular response to heating. In this dissertation, we employ the well-known Pennes' bioheat transfer equation to predict the degree of skin burn and the temperature distribution in hyperthermia cancer treatment.

A fourth-order compact finite difference scheme is developed to solve Pennes' bioheat transfer equation in a three-dimensional single …

Modeling Of Solid Layer Growth At A Constant Speed In A Binary Melt Crystallization Process, Zongwen Feng

Doctoral Dissertations

Melt crystallization is an attractive separation method for the purification of organics at a large scale. Because the geometry of the rigid crystal lattice is peculiar to the particular substance, most crystallization processes form eutectic systems. The kinetics of crystallization limit the rate in which crystal growth can occur without the incorporation of undesired impurity. If the rate of heat transfer exceeds the mass transfer rate of the impurity, the impurity can solidify, contaminating the product. In practice, one would like to specify a crystallization rate and determine the temperature profile of the crystallizer wall that would achieve this rate. …

Mathematical And Empirical Modeling Of Chemical Reactions In A Microreactor, Jing Hu

Doctoral Dissertations

This dissertation is concerned with mathematical and empirical modeling to simulate three important chemical reactions (cyclohexene hydrogenation and dehydrogenation, preferential oxidation of carbon monoxide, and the Fischer-Tropsch (F-T) synthesis in a microreaction system.

Empirical modeling and optimization techniques based on experimental design (Central Composite Design (CCD)) and response surface methodology were applied to these three chemical reactions. Regression models were built, and the operating conditions (such as temperature, the ratio of the reactants, and total flow rate) which maximize reactant conversion and product selectivity were determined for each reaction.

A probability model for predicting the probability that a certain species …

Silicon Based Micro Components For Use In Chemical Agent Detection, Scott R. Forrest

Doctoral Dissertations

The objective of this work was to model, fabricate and test silicon based micro components for applications in chemical agent detection. Part I deals with research done on tunable micro Fabry-Perot interferometers. These devices are designed for use in identifying chemicals that absorb radiation in the infrared range of the spectrum. Part II deals with research done on novel Layer by Layer (LbL) assembled enzyme microreactors. These devices are designed for use in identifying chemicals that absorb radiation in the ultraviolet and visible range of the spectrum.

The emphasis of Part I is on the design and modeling of Fabry-Perot …

The Application Development Outsourcing Contract Decision: The Effect Of Service Quality, Relationship Quality, Satisfaction, And Switching Costs On Continuation And Discontinuation Decisions, G. Dwayne Whitten

Doctoral Dissertations

Although the popularity of IT outsourcing has grown over the last two decades, approximately one third of outsourcing contracts are discontinued. This discontinuation of contracts has resulted in renegotiations with the original outsourcing vendor, switching to another vendor, and backsourcing, or the return of previously outsourced functions in-house.

IT outsourcing is expected to grow to a $160 billion industry in the United States alone by 2005. Given the conclusion by some researchers that so many outsourcing arrangements end in vendor switches or backsourcing, it is apparent that a large amount of money is being needlessly wasted. By better understanding the …

Head Losses Occurring Through Smooth Pipe Fittings, Liner Folds And Fusion Joints, Ellis Dale Hart

Doctoral Dissertations

This dissertation has involved laboratory and analytical studies of pipe head losses which were caused by: (a) smooth wye and tee fittings of 4-inch and 6-inch diameter with corresponding 4-inch and 6-inch laterals, (b) pipe liner folds created by inadequate stretching of the liner during placement, and (c) fusion joints which protrude a short distance into the pipe causing a small but unknown head loss. Though the individual loss was found to be small, cumulative losses could prove worthy of design consideration.

The velocity and head loss measurements were made using either a 4-inch or 6-inch model diameter pipe. Having …

Novel Sensors For Neural Glucose Concentration Based On Enzyme Fluorescent Thin Films Fabricated On Nanoparticle Carriers Using Electrostatic Layer -By -Layer Assembly, Patrick Scott Grant

Doctoral Dissertations

Currently, there is no means by which rapidly fluctuating glucose and lactate levels can be monitored simultaneously. This dissertation demonstrates that by combining the broad-band versatility of fluorescence spectroscopy with nanoassembly methods, it is possible to construct micro- and nanoscale sensors with precise composition and short diffusion length constant. The work is significant because of its potential as a platform for discovery of basic normal physiological processes that have previously been hidden from researchers' views, more detailed studies of responses to drugs or other stimuli, and even clinical monitoring. The main goal of this work was to develop novel methods …

Fatigue Of Drill Pipes Used In Horizontal Directional Drilling, Feibai Ma

Doctoral Dissertations

Fatigue is the most common cause of mini-HDD drill rod failure. It can occur at stress levels far below the normal operating stress in most drill stem components. Fatigue failures occur because the drill rod, after it has been forced into a curved path, undergoes a cyclic bending stress oscillating from tension to compression in concert with the other stress components caused by torque, thrust, or pullback.

When a rod breaks underground, there is considerable extra cost caused by the delay in “fishing” out the broken rod as well as the cost of replacing the rod. On the other hand, …

Fabrication, Characterization, And Chemical Sensing Of Silicon Dioxide Microcantilevers, Yanjun Tang

Doctoral Dissertations

The objective of this work is to design and fabricate an advanced silicon dioxide microcantilever sensor and to investigate chemical and biological sensing by microtechnology.

Microcantilever sensor technology has many advantages including fast response time, lower cost of fabrication, the possibility of sensor arrays with small overall dimensions, the ability to explore microenvironments, and improved portability for field applications. For all of these advantages, microcantilever chemical and biological sensors have drawn more and more attention.

So far, all other microcantilevers were designed and fabricated for AFM applications. We developed a novel SiO2 microcantilever especially for chemical and biological sensor applications. …

A Numerical Method To Solve The Two-Step Parabolic Heat Transport Equations In A Microsphere Subjected To An Ultrafast Laser Pulse, Ibrahima Khalil Fiman Kaba

Doctoral Dissertations

Heat transport at the microscale is the subject of intense investigation due to the growing need to fabricate microstructures for applications in nanotechnology. The need to control the spread of the thermal process zone has led to the development of high power short-pulse lasers. During thermal processing, impurities may form in the material. An amplification of the thermal energy around the impurities may result in severe damage occurring or in the failure of the thermal process. A thorough analysis of the way the impurities dissipates the thermal energy is therefore necessary to minimize the potential damage and optimize the thermal …

Examining The Role Of Social Capital In Community Development: How The Creation Of A Land Trust Set A Small Town On The Path To Sustainability, Lynda A. Brushett

Doctoral Dissertations

Theoretical constructs of social capital and sustainable community development are examined through the lens of the lived experience of a small Vermont town. A case study of the community's land use planning history from the 1960's through to the present assesses the actions and relationships among individuals and institutions engaged in civic efforts to achieve environmental, economic, and social balance in development decision-making. The role of a land trust and its members as a community system changing variable---a self-organized institutional response to the concerns of citizens to the unsustainable development of their community---is evaluated. Findings describe the process whereby social …

Development Of Hydraulic Relationships For Estimating In-Bank River Discharge Using Remotely Sensed Data, David Michael Bjerklie

Doctoral Dissertations

An evaluation of river hydraulic data currently or potentially available from satellite and other remote platforms was completed, and a set of discharge estimation models proposed that can use the remotely sensed information to estimate discharge with reasonable accuracy. Reasonable accuracy is defined as within +/-20% of the observed on average for a large number of estimates. The proposed estimation models are based on the Manning and Chezy flow resistance equations, and utilize combinations of potentially observable variables including water-surface width, maximum-channel (or bankfull) width, mean water depth, mean maximum-channel depth, mean water velocity, and channel slope. Both statistically and …

Multiple Steady Solutions And Bifurcations In The Symmetric Driven Cavity, Kahar Bin Osman

Doctoral Dissertations

The symmetric driven cavity with sinusoidal forcing for two- and three-dimensions is considered. Results are obtained via numerical computations of the Navier Stokes equations with constant density. The numerical integration is a splitting method, using the Crank-Nicholson method for linear terms and the second-order Adams-Bashforth method for the non-linear terms. Spatial derivatives are evaluated with finite differences, and matrix equations are treated with SOR by lines. The results show symmetric solutions for low Reynolds numbers and asymmetric solutions for higher Reynolds numbers. Subcritical bifurcations are observed for two-dimensional flow. Unsteady flow behavior occurs at higher Reynolds number. Three-dimensional simulations for …

Effective Elastic Properties Of Two -Dimensional Solids With Inhomogeneities Of Irregular Shapes, Jindrich Novak

Doctoral Dissertations

This work investigates the effective elastic properties of two-dimensional solids with inhomogeneities of various shapes. We develop a special procedure to evaluate the contribution of irregularly shaped inhomogeneities to these properties. The method can also be used to investigate the stress concentrations around the inhomogeneities. The procedure is based on the analysis of a representative volume element. We express the contribution of each inhomogeneity to the overall moduli of the composite in terms of the compliance contribution tensor. To calculate the components of this tensor, we devise a method that combines analytical and numerical approaches: Kolosov-Muskhelishvili complex variable technique and …

Arthur Raper: Modern Realist In The New Deal South, Louis Mazzari

Doctoral Dissertations

Arthur Raper was a progressive sociologist and controversial voice for racial and social equality in the South during the 1920s and 1930s. Son of a white, North Carolina farm family, Raper became allied with modernist voices at Chapel Hill and the University of Chicago. Raper's research was widely discussed through the region and greatly influenced Southern race relations in the years leading to the civil rights movement.

Raper was the first white southerner to look critically and scientifically at the causes of racial violence. The Tragedy of Lynching (1933) was reviewed in hundreds of Southern newspapers and discussed throughout the …

A Loss Of Will: "Arminianism," Nonsectarianism, And The Erosion Of American Psychology's Moral Project, 1636--1890, Russell D. Kosits

Doctoral Dissertations

The concept of "the will" dominated American moral psychology for nearly three centuries. To possess a will was, among other things, to be made in the image of God and to have moral responsibility. College textbooks, as tools of moral inculcation, conveyed this moral psychology from the seventeenth to the early twentieth century. A significant shift occurred in college psychology textbooks during the 1930s: the topic of will was being removed as a chapter heading---never to return. By the end of the decade, American psychology had lost its will.

What explains this "loss of will" in American psychology? From a …

Ocean Color Modeling: Parameterization And Interpretation, Hui Feng

Doctoral Dissertations

The ocean color as observed near the water surface is determined mainly by dissolved and particulate substances, known as "optically-active constituents," in the upper water column. The goal of ocean color modeling is to interpret an ocean color spectrum quantitatively to estimate the suite of optically-active constituents near the surface. In recent years, ocean color modeling efforts have been centering upon three major optically-active constituents: chlorophyll concentration, colored dissolved organic matter, and scattering particulates. Many challenges are still being faced in this arena. This thesis generally addresses and deals with some critical issues in ocean color modeling.

In chapter one, …

Linking Focus And Context In Three-Dimensional Multiscale Environments, Matthew D. Plumlee

Doctoral Dissertations

The central question behind this dissertation is this: In what ways can 3D multiscale spatial information be presented in an interactive computer graphics environment, such that a human observer can better comprehend it? Toward answering this question, a two-pronged approach is employed that consists of practice within computer user-interface design, and theory grounded in perceptual psychology, bound together by an approach to the question in terms of focus and context as they apply to human attention. The major practical contribution of this dissertation is the development of a novel set of techniques for linking 3D windows to various kinds of …

Reaching Beyond Compliance: Obstacles To Integrating Sustainability Into Decision -Making Processes In An Institution Of Higher Education, Julie Newman

Doctoral Dissertations

There are emerging opportunities for institutions of higher education to respond to current environmental and public health crises. By setting institutional examples and modeling for others how to prioritize sustainability as a grounding framework for decision-making, institutions of higher education have an opportunity to facilitate society's transition to a more sustainable future. Sustainability principles stem from an international consensus that the pursuit of economic viability as an end in itself, conditioned by a neo-classical model of economics, does not maintain or enhance ecological health and human well-being. There are a number of universities worldwide who are making an effort to …

The Influence Of Urbanization On Runoff Generation And Stream Chemistry In Massachusetts Watersheds, Brian A. Pellerin

Doctoral Dissertations

The conversion of forested and agricultural land to suburban and urban landscapes is a dominant land use change dynamic in the United States and has implications for watershed hydrology and water quality. Here I evaluate the effect of integrated landscape features (e.g., percent residential or developed) and watershed-scale attributes influenced by urbanization on stream nutrient concentrations in headwater catchments in Massachusetts. In addition, I evaluate the importance of surface versus subsurface flow paths during rainfall events in stormflow generation in a small urban catchment. The percentage of residential land explains 52% of the variability in mean annual nitrate (NO3) concentrations …

Contributions To Predicting Contaminant Leaching From Secondary Materials Used In Roads, Defne S. Apul

Doctoral Dissertations

Slags, coal ashes, and other secondary materials can be used in road construction. Both traditional and secondary materials used in roads may contain contaminants that may leach and pollute the groundwater. The goal of this research was to further the understanding of leaching and transport of contaminants from pavement materials. Towards this goal, a new probabilistic framework was introduced which provided a structured guidance for selecting the appropriate model, incorporating uncertainty, variability, and expert opinion, and interpreting results for decision making. In addition to the framework, specific contributions were made in pavement and embankment hydrology and reactive transport, Bayesian statistics, …

Granite: A Scientific Database Model And Implementation, Philip J. Rhodes

Doctoral Dissertations

The principal goal of this research was to develop a formal comprehensive model for representing highly complex scientific data. An effective model should provide a conceptually uniform way to represent data and it should serve as a framework for the implementation of an efficient and easy-to-use software environment that implements the model. The dissertation work presented here describes such a model and its contributions to the field of scientific databases. In particular, the Granite model encompasses a wide variety of datatypes used across many disciplines of science and engineering today. It is unique in that it defines dataset geometry and …

Study Of The Enhancement Effect Of Cyclopentadecanolide On Protein Permeation Through Lipid Membranes, Zhengmao Li

Doctoral Dissertations

Intranasal drug delivery has been a topic of increasing interest for a decade as a convenient and reliable method for the systemic administration of drugs. The low bioavailability of simple formulation of protein drugs, such as insulin, can be greatly improved by using permeation enhancers. We studied the effect of cyclopentadecanolide (CPE-215RTM) as a permeation enhancer in protein release through lipid bilayer membranes. We successfully designed a novel in-vitro membrane permeability model using liposomes and performed a series of transmembrane protein release experiments. These were carried out under a wide range of conditions in the presence of different permeation enhancer …

Nucleation And Growth Kinetics Of Tin And Tin -Silver Alloy During Initial Stages Of Electrodeposition, Zhongqin Zhang

Doctoral Dissertations

Electrodeposition has played an essential role in electronics packaging because it gives superior thickness control for chip interconnects. Pure tin, tin-silver and tin-silver-based solders have been identified as leading candidates for lead-free solders due to the desirable melting point, good creep resistance and thermo-mechanical behavior.

The initial stage of electrodeposition, or the formation of small clusters of atoms (nuclei), is significant in the overall electrodeposition kinetics, as well as the appearance, structure, and properties of the resulting coatings. In this work, nucleation and growth kinetics of tin and tin-silver electrodeposition on copper and nickel substrates were investigated by electrochemical methods …

Needling Doubts: A Sociological Examination Of Parental Resistance To Childhood Immunizations, Catherine L. Moran

Doctoral Dissertations

Within recent years, a group of parents who question or oppose vaccination has emerged in the United States. While recently receiving attention within medicine and public health, parental questioning of and resistance to childhood immunization is a trend that has yet to be examined within sociology. This dissertation explores the role of parental characteristics, beliefs, and attitudes on resistance to pediatric immunization.

Thirty-five in-depth interviews with parents who postponed or refused vaccinations for their children were conducted. Qualitative data were used to develop a survey instrument including a series of scales measuring parental beliefs and attitudes about pediatric vaccination. The …

On The Rayleigh -Brillouin Scattering In Air, Qiuhua Zheng

Doctoral Dissertations

GroundWinds lidar system is a high-spectral-resolution lidar system that can directly measure the Rayleigh-Brillouin scattering (RBS) spectra, from which the wind, temperature, and turbulence in the troposphere can be measured. Its transmitter is a double-frequency Nd-YAG laser at 532nm. Most of the data used in this research were taken on 31 July 2002.

A widely used mathematic model---the S6 model---is fitted to the measured RBS spectra. The discrepancies between the measured temperature from the RayleighBrillouin spectra and from the radiosonde, combined with the discrepancies between the model and the measured RBS spectra, indicate that there is room for the S6 …