Digital Commons Network^™

Three Elements Of Self-Regulated Learning: Metacognitive Functioning, Self-Efficacy, And Study Behavior, Catherine E. Overson

Doctoral Dissertations

Individuals' metacognitive insight regarding their own performances -- what people think they know about what they know -- is often flawed. Students' metacognitive functioning was examined in two studies. In Study 1, exam performance estimates compared with actual scores were assessed across three in-class exams. Results demonstrated a systematic tendency for lower performers to overestimate their exam performances. Top performers underestimated their performance. In Study 2, an incentive to be as accurate as possible in exam performance estimations ($50 gift card) did not reduce estimation miscalculations for either bottom or top performers.

In Study 1, higher levels of students' self-efficacy …

Ocular Dominance And Temporal Dynamics In The Venetian Blind Effect, Joshua Jay Dobias

Doctoral Dissertations

The visual system can use small disparities between the stimuli seen by each eye as a binocular cue for depth. Geometric disparities are the most commonly used cue for stereopsis, but disparities in contrast and luminance can also lead to the perception of depth and both can cancel perceived depth from a geometric disparity. Humans are able to perceive changes in depth from contrast disparities at frequencies up to approximately 1.4 Hz, whereas changes in depth from geometric disparities are visible at frequencies above 5 Hz (Dobias, 2008). This dissertation is divided into two parts. The first part (experiments 1 …

Evaluating Mode Of Loading Effect And Laboratory Fatigue Performance Of Asphalt Concrete Using Viscoelastic Continuum Damage Mechanics, Aravind Krishna Swamy

Doctoral Dissertations

In this research, an existing uniaxial constitutive model has been extended to flexural loading mode and a new approach to predict fatigue behavior is proposed. The proposed methodology involves dynamic modulus testing to obtain viscoelastic properties and subsequent fatigue testing. Several asphalt concrete beams were tested according to the proposed methodology. The analysis of data indicates that there exists a unique relationship between the flexural pseudostiffness and amount of damage in the specimen. To verify the accuracy of the fatigue prediction model, fatigue tests were conducted on specimens that were not part of preliminary analysis. The fatigue life predictions made …

Development Of Engineering Tools To Analyze And Design Flexible Structures In Open Ocean Environments, Judson Decew

Doctoral Dissertations

Methods to effectively predict system response in marine settings are critical in the engineering design process. The high energy ocean environment can subject structures to large wave and current forces, causing complex coupled motions and loads. This research focused on the development of effective methods to predict flexible system response and the structural integrity of marine High Density Polyethylene (HDPE) components. Numerical modeling tools were developed to analyze and design flexible structures in open ocean environments. Enhancements to the University of New Hampshire's Aqua-FE finite element computer program were performed, including expansion of the element library to include spherical geometries …

"If We Want An Education, We Want An Education It's Our Choice": How Four Youth At Risk Of Dropping Out Of High School Experienced Social Capital, Joanne Mcfarland Malloy

Doctoral Dissertations

Youth who are at risk of dropping out of high school are often challenged by significant emotional and behavioral support needs, and are typically disengaged from the educational process and the social networks that can help them succeed in their homes, in school, and in their communities. This research project investigated the experiences of four youth, two females and two males, who were at significant risk of dropping out of high school as they were engaged in a supportive intervention designed to build skills in self-determination, school-to-adult life transition planning, and leveraging social resources. Using social capital as a sensitizing …

Models And Methods For Computationally Efficient Analysis Of Large Spatial And Spatio-Temporal Data, Chengwei Yuan

Doctoral Dissertations

With the development of technology, massive amounts of data are often observed at a large number of spatial locations (n). However, statistical analysis is usually not feasible or not computationally efficient for such large dataset. This is the so-called "big n problem".

The goal of this dissertation is to contribute solutions to the "big n problem". The dissertation is devoted to computationally efficient methods and models for large spatial and spatio-temporal data. Several approximation methods to "the big n problem" are reviewed, and an extended autoregressive model, called the EAR model, is proposed as a parsimonious model that accounts for …

Efficiency Of The Built Environment: Interdependencies In Transportation, Development Form And Public Health, Cynthia H. Carlson

Doctoral Dissertations

Retrofitting existing neighborhoods and communities to remove barriers to walking and allow residents to choose walking as a mode of transportation has the potential to both stabilize energy used for transportation and transportation infrastructure and provide physical activity for improved health, shifting the energy used for transportation from cars to people. This study brings together community-based research, an interdisciplinary team approach, and multi-level modeling to investigate how community design impacts transportation behavior in the context of smaller, northeastern cities.

Ten neighborhoods of varying design, connectivity, proximity to services, and average income were selected in each of the cities for a …

Wireless Sensor Integrated Tool For Characterization Of Machining Dynamics In Milling, Christopher Adam Suprock

Doctoral Dissertations

A first step towards practical sensing in the machining environment is the development and use of low cost, reliable sensors. Historically, the ability to record in-process data at an end mill tool tip has been limited by the sensor location. Often, these sensors are mounted on the material workpiece or the machine spindle at significant physical distance from the cutting process. Of specific interest are the problems of tool chatter which causes limitations to productivity and part quality. Although tool chatter is a substantial issue in machining, it remains an open research topic. In this research, a sensor integrated cutting …

Chemistry Of Acenes, [60]Fullerenes, Cyclacenes And Carbon Nanotubes, Chandrani Pramanik

Doctoral Dissertations

In the present work, we studied the chemistries of acenes, cyclacenes, [60]fullerenes and CNTs. Acenes are well known organic semiconductors. Pentacene is a benchmark organic semiconductor due to low HOMO-LUMO gap and high charge carrier mobilities in its thin film. Its poor solubility and instability, however, limit its utility and overall cost effectiveness. We successfully synthesized several sulfur-functionalized acene derivatives that overcome these problems. However, we also encountered difficulties to aromatize some of these derivatives. To circumvent these problems, we studied some new synthetic routes to sulfur-functionalized anthracenes, pentacenes and nonacenes. Additionally, the electronic properties of substituted acenes were compared …

Design Of A Low Power Switched-Capacitor Pipeline Analog-To-Digital Converter, Gang Chen

Doctoral Dissertations

An Analog to Digital Converter (ADC) is a circuit which converts an analog signal into digital signal. Real world is analog, and the data processed by the computer or by other signal processing systems is digital. Therefore, the need for ADCs is obvious.

In this thesis, several novel designs used to improve ADCs operation speed and reduce ADC power consumption are proposed. First, a high speed switched source follower (SSF) sample and hold amplifier without feedthrough penalty is implemented and simulated. The SSF sample and hold amplifier can achieve 6 Bit resolution with sampling rate at 10Gs/s.

Second, a novel …

Examining The Relationship Between Social Capital And The Built Environment: A Case Study In Measuring Community Sustainability, Shannon H. Rogers

Doctoral Dissertations

The concepts of sustainability and sustainable development are frequently described as having three main components, sometimes referred to as the three pillars or the triple bottom line: environmental, economic, and social. Because the origins of sustainability come from a desire to right environmental wrongs much consideration has been given to the environmental issues, especially how they interface with economic ones. Frequently mentioned but rarely examined, the social aspects of sustainability have been considered the weakest and least described pillar. This work explores the utility of social capital, the value of one's networks and connections, as a measure of sustainability. As …

Analytical And Numerical Prediction Of Localized Necking In Sheet Metal Forming Processes, Raed Zuhair Hasan

Doctoral Dissertations

The goal of this research is to investigate, develop and validate analytical and numerical tools that can accurately predict failure in sheet metal forming operations. The strain-based forming limit curve (FLC) is one of the tools to predict the maximum permissible strains of thin metallic sheets which are loaded in the plane of the sheet to different states of stress. It may be used to assess forming operations in the press shops as well as unintentional deformations, such as vehicle, aircraft, or train crashes. The accurate prediction of failure in sheet metal stamping can shorten product lead times, decrease tooling …

From Sweetwater To Seawater: An Environmental History Of Narragansett Bay, 1636--1849, Christopher L. Pastore

Doctoral Dissertations

This dissertation examines environmental change on and around Narragansett Bay from first European settlement in 1636 to the dissolution of the Blackstone Canal Company in 1849. It uses one of the largest estuaries on the East Coast and one situated at the heart of early English settlement in New England as a means to write estuaries into Atlantic history. Examining the ecological and epistemological complexities that arose at the nexus of land and sea, where improvable space and the push of "progress" met an eternal or "profound" ocean, this study reframes estuaries as watery borderlands that people used but never …

Detection Of Mortality In Tropical Forests Using Remote Sensing: From Treefall Gaps To Large Disturbances, Fernando Del Bon Espirito-Santo

Doctoral Dissertations

The frequency, severity, and intensity of natural disturbances in tropical forests continually re-shape forest structure. At small scale, branch or tree-falls gaps and subsequent recovery are important mechanisms for carbon cycling. At landscape scale, large disturbances (blow-downs) may also play a role on the structure and composition of tropical forests. Quantitative studies of natural disturbances across the occurrence spectrum (branch fall-gaps to blow-downs) are rare for the Amazon. Remote sensing coupled with intense field work data collection provides the means to analyze the dynamic of tropical forests at multiple scales. In this dissertation three aspects of natural disturbances were examined: …

In-Situ Early Detection Of Metal Corrosion Via "Turn-On" Fluorescence In "Smart" Epoxy Coatings, Anita Augustyniak

Doctoral Dissertations

Organic coatings (e.g., epoxy coatings) have been widely used to protect metal and metal alloys against corrosion. However protective coating fails with time, leading to corrosion of the metal substrate. When localized corrosion occurs, without being detected, it can result in disastrous failure of the metal structure. The purpose of this thesis is to develop a "smart" epoxy coating system that detects early stages of metal corrosion via indicators molecules embedded in the coating that fluoresce when triggered by ions liberated from corrosion. This fluorescence can be easily and non-destructively detected and thus further material damage can be prevented by …

A Computational Fluid Dynamics Study Of Two-Phase Flows In The Presence Of Surfactants, Yuanyuan Cui

Doctoral Dissertations

Drop formation in co-flowing fluids and drops rising in a tube are important in applications such as microencapsulation and enhanced oil recovery. A hybrid volume-of-fluid method with a front-tracking scheme is developed to study two-phase flows in the presence of surfactants at finite Reynolds numbers. Both fluids can be Newtonian or shear-thinning, and surfactants are soluble in the adsorption-desorption limit. A drop in the co-flowing geometry typically breaks up at the primary neck. The drop breaks faster with smaller volumes as the outer flow rate increases or the drop viscosity decreases. When surfactants are present, they accumulate in the neck …

Artifact-Based Reflective Interviews For Identifying Pragmatic Epistemological Resources, Christopher Walden Shubert

Doctoral Dissertations

Physics Education Research studies the science of teaching and learning physics. The process of student learning is complex, and the factors that affect it are numerous. Describing students' understanding of physics knowledge and reasoning is the basis for much productive research; however, such research fails to account for certain types of student learning difficulties. In this dissertation, I explore one source of student difficulty: personal epistemology, students' ideas about knowledge and knowing.

Epistemology traditionally answers three questions: What is knowledge? How is knowledge created? And, how do we know what we know? An individual's responses to these questions can affect …

Assessing Social-Ecological Resilience And Adaptive Capacity In The Face Of Climate Change: An Examination Of Three Communities In The Crown Of The Continent Ecosystem, Bradley B. Johnson

Doctoral Dissertations

This research examines the social-ecological resilience and adaptive capacity of the Crown of the Continent Ecosystem through a suite of three case study communities and the impacts of climate change on the ecosystem's hydrologic regime. The Crown of the Continent Ecosystem spans the U.S.-Canadian border; case study communities composed of Kalispell and Choteau, Montana and Fernie, British Columbia fall on both sides of the border.

Primary data was gathered through a "bottom-up" qualitative approach utilizing an online survey followed by a semi-structured interview process with stakeholders in natural resource dependant industries and government at the local, state, and federal levels …

High Lundquist Number Simulations Of Parker's Model Of Coronal Heating: Scaling And Current Sheet Statistics Using Heterogeneous Computing Architectures, Liwei Lin

Doctoral Dissertations

Parker's model [Parker, Astrophys. J., 174, 499 (1972)] is one of the most discussed mechanisms for coronal heating and has generated much debate. We have recently obtained new scaling results for a 2D version of this problem suggesting that the heating rate becomes independent of resistivity in a statistical steady state [Ng and Bhattacharjee, Astrophys. J., 675, 899 (2008)]. Our numerical work has now been extended to 3D using high resolution MHD numerical simulations. Random photospheric footpoint motion is applied for a time much longer than the correlation time of the motion to obtain converged average coronal heating rates. Simulations …

Polyamine Metabolism In Arabidopsis: Transgenic Manipulation And Gene Expression, Rajtilak Majumdar

Doctoral Dissertations

The metabolism of polyamines (Putrescine, Spermidine and Spermine) in wild type and transgenic Arabidopsis thaliana (Col 0 ecotype) plants was studied using the techniques of transgenic manipulation and gene expression. Two specific objectives were: (1) To study the effects of inducible and constitutive transgenic manipulation of polyamines via a mouse ornithine decarboxylase (mODC) gene on plant metabolism. (2) To analyze the spatial and temporal expression patterns of Arabidopsis thaliana S-adenosylmethionine decarboxylase genes (AtSAMDC3, AtSAMDC4 and AtSAMDC5) during its life cycle.

The major findings are: (i) Orn becomes a limiting substrate for Put biosynthesis in transgenic Arabidopsis expressing mODC gene, (ii) …

Hydrogenation Of Nanostructured Carbon, Synthesis Of Organic Semiconductors And Progress Towards Synthesis Of Fullerenes And Nanoribbons From Polyaromatic Hydrocarbons, Jeremy T. Kintigh

Doctoral Dissertations

The hydrogenation of carbon allotropes including fullerenes, nanotubes and graphene was investigated using polyamines as hydrogenation reagents. In each case, a rapid, scalable and reversible hydrogenation was observed. The mechanism of hydrogenation was explored using several different polyamines. It was shown that a two-carbon spacer between amine groups is critical for efficient hydrogenation, as well as the presence of at least two adjacent amines that are not tertiary. The extent of hydrogenation on the fullerenes is a function of reaction temperature. C3nuC 60H18 forms preferentially at approximately 200 °C whereas C60H36 species are preferentially formed at approximately 340 °C and …

Statistical Study Of Oxygen+ Transport From The Cusp To The Plasmasheet, Jing Liao

Doctoral Dissertations

Using Cluster/CODIF data, we have determined the occurrence frequency of the cusp-source O+ in the magnetotail to determine where and when it is observed. The results show that the probability to observe O+ along the transport path is high even during nonstorm times, although, as expected, the highest probability is found during storm times. In addition to the outflow rate increasing, the transport path itself also changes during storm times, bringing more O+ to the near-earth plasma sheet. Interplanetary magnetic field (IMF) magnitude is the most effective driver for bringing O+ into the near-Earth lobes. It was also found that …

Sub Pixel Analysis And Processing Of Sensor Data For Mobile Target Intelligence Information And Verification, Theresa Allen Williams

Doctoral Dissertations

This dissertation introduces a novel process to study and analyze sensor data in order to obtain information pertaining to mobile targets at the sub-pixel level. The process design is modular in nature and utilizes a set of algorithmic tools for change detection, target extraction and analysis, super-pixel processing and target refinement. The scope of this investigation is confined to a staring sensor that records data of sub-pixel vehicles traveling horizontally across the ground. Statistical models of the targets and background are developed with noise and jitter effects. Threshold Change Detection, Duration Change Detection and Fast Adaptive Power Iteration (FAPI) Detection …

Investigation Of Microbubble/Droplet Formation In Cross-Flow And Co-Flow Micro Devices, Tom J. John

Doctoral Dissertations

The primary goal of the work presented in this dissertation is to generate microbubbles of a diameter of less than 15μm inside micro channels. In order to achieve this detailed understanding, the facts and limitations behind the generation of microbubbles inside a micro channel are determined from existing literature. The major limitations of the current bubble/droplet generators are found to be the bubble confinement effect, the merging of bubbles, the difficulty in determining bubble diameter and the need for smaller channels to generate smaller bubbles. A device eliminating these drawbacks is conceptualized, and its feasibility is studied using COMSOL® and …

Strength Adjustable Preformed Particle Gels For Conformance Control, Jia Zhou

Doctoral Dissertations

"Reservoir heterogeneity and early water breakthrough (also known as fingering) represent two of the greatest challenges to recover crude oil efficiently. Gel treatments have been implemented as a cost-effective method to plug high permeability zones and thus improve sweep efficiency in reservoirs. However, when extensive cross-flows exist between formation layers, gel treatments become less efficient. Polymer was used in polymer flooding to increase the viscosity of the injected fluids and to correct the fingering problem. However, such treatment may be uneconomical since dramatic viscosity loss (80-90%) is caused by shearing degradation during the injection process near the wellbore.

This research …

Advanced Composites Using Non-Autoclave Processes: Manufacturing And Characterization, V. G. K. Menta

Doctoral Dissertations

"The objective of the present study is to develop non-autoclave processes to manufacture high performance composites for aerospace applications. In Paper 1, vacuum assisted resin transfer molding (VARTM) process was developed for elevated temperature composites. Use of VARTM process for fabricating high temperature resins presents unique challenges such as high porosity and low fiber volume contents. Two different vacuum bagging methods: Seeman Composite Resin Infusion Molding Process (SCRIMP) and Double Vacuum Bagging Infusion (DVBI) process were evaluated. Flow simulation tool was used to predict key flow parameters needed for the successful infusion. In Paper 2, honeycomb sandwich panels were manufactured …

Part-I Characterization Of Phorbol Ester; The Predominant Toxic Component Of Jathropha Curcas And Development Of An Efficient Process For The Detoxification Of Jathropha Curcas Meal Part-Ii Quantification Of 2-Hydroxy-4-(Methylthio) Butanoic Acid And Pantothenic Acid In Bovine Serum And Sea Water Matrices, Balaji Viswanathan

Doctoral Dissertations

"Jatropha curcas is has often been touted as the most sustainable biofuel source. Jatropha curcas is a drought resistant perennial plant belonging to the Euphorbiaceae family. Interest in this plant as a biofuel source is related to high lipid (triglyceride) content of its seeds. However, economics of jatropha as a biofuel source has been marred by the toxicity of the oil and its protein rich meal. As a result of high toxicity the protein rich meal is used only as a very low or no economic value organic fertilizer. Economic return from jatropha can be dramatically enhanced through development of …

Aerogels And Films Through Free Radical Polymerization, Anand G. Sadekar

Doctoral Dissertations

"Aerogels are porous lightweight materials, unique among all solids in terms of low density, low thermal conductivity, low dielectric constants and high acoustic attenuation. The penalty for those exceptional properties is fragility. That issue has been addressed by bridging covalently (crosslinking) the elementary nanoscopic building blocks of silica aerogels with polymers. To streamline the crosslinking process we synthesized a bidentate free radical initiator (Si-AIBN) that gets attached on the skeletal nanoparticles and induces crosslinking by surface initiated polymerization (SIP). Here, we extend the scope of Si-AIBN in two directions: (a) we demonstrate extremely adhering, covalently attached polymer coatings on oxidized …

Assessing System Architectures: The Canonical Decomposition Fuzzy Comparative Methodology, Jason Paul Dauby

Doctoral Dissertations

"The impacts of decisions made during the selection of the system architecture propagate throughout the entire system lifecycle. The challenge for system architects is to perform a realistic assessment of an inherently ambiguous system concept. Subject matter expert interpretations, intuition, and heuristics are performed quickly and guide system development in the right overall direction, but these methods are subjective and unrepeatable. Traditional analytical assessments dismiss complexity in a system by assuming severability between system components and are intolerant of ambiguity. To be defensible, a suitable methodology must be repeatable, analytically rigorous, and yet tolerant of ambiguity. The hypothesis for this …

Hilbert Transform Applications In Signal Analysis And Non-Parametric Identification Of Linear And Nonlinear Systems, Zuocai Wang

Doctoral Dissertations

"Hilbert Huang Transform faces several challenges in dealing with closely-spaced frequency components, short-time and weak disturbances, and interrelationships between two time-varying modes of nonlinear vibration due to its mixed mode problem associated with empirical mode decomposition (EMD). To address these challenges, analytical mode decomposition (AMD) based on Hilbert Transform is proposed and developed for an adaptive data analysis of both stationary and non-stationary responses. With a suite of predetermined bisecting frequencies, AMD can analytically extract the individual components of a structural response between any two bisecting frequencies and function like an adaptive bandpass filter that can deal with frequency-modulated responses …