Digital Commons Network^™

The Early Academic Growth Of Children Of U.S. Immigrants: A Longitudinal Analysis, Por-Fu A. Chen

Doctoral Dissertations

Once considered academically at risk, children of immigrants are now widely regarded as beholders of educational advantages. The research evidence asserting these advantages comes mostly from examining adolescents and young adults. Contrastingly, the small number of studies on younger children disagrees over whether those with foreign-born parents lag or lead in early years of schooling. This age bias impedes a more comprehensive understanding of their academic trajectories, and limits how the educational advantages may be theorized.

This dissertation adopts a longitudinal approach to examine academic differences by parental nativity and race between kindergarten and eighth grade. Through estimating achievement gaps …

Optimizing Design Parameters For Thin Film Composite Hollow Fiber Membranes And Modules For Osmotic Processes, Jian Ren

Doctoral Dissertations

Osmotic processes have been considered sustainable solutions for extracting clean water and concentrating impaired water by forward osmosis (FO) and harvesting the osmotic pressure gradient for power generation via pressure retarded osmosis (PRO). Thin film composite (TFC) membranes are considered a preferred platform for osmotic processes wherein the selective and support layers can be tailored independently for preferred chemistry and structure. Hollow fiber TFC membranes in particular have garnered interests because of their high packing density. In this dissertation study, high performance TFC membranes were designed for applications in osmotic processes. Departing from previous hollow fiber membrane developments that focused …

Improving Effects Of Sampling Time In Fast Adaptation-Based Control Algorithms With Applications, John R. Cooper

Doctoral Dissertations

Over the past decade, L1 adaptive control has emerged as viable control architecture for systems with unmodeled dynamics and time-varying uncertainties. L1 control uses a concept known as "fast adaptation" to estimate uncertainties. This means the controller relies on high sampling rates. However, in any real-world application, sampling speed is limited by hardware capabilities. Thus the question of how to obtain better performance at slower sampling rates in fast adaptation-based algorithms has become an important research topic. This dissertation presents two methods of online modeling to solve this problem. The first of these is function approximation using artificial neural networks. …

Modeling Enhancement And Intelligent Inference Of Impedance-Based Structural Health Monitoring, Qi Shuai

Doctoral Dissertations

Archival abstract submitted

Developing A Flexible Disaster Relief Supply Chain Model, Eric Hoffman

Doctoral Dissertations

Archival abstract submitted

A Grounded Theoretical Analysis Of Team Resilience In The Us Army, Megan L. Dove-Steinkamp

Doctoral Dissertations

In order to develop a scientific understanding of team resilience, the three primary goals of the current research effort were to (1) summarize the research literature on resilience in and of small groups and systems, (2) articulate a framework to direct the synthesis of existing and future resilience-related research, and (3) construct a substantive theory of team resilience. This exploratory research used a grounded theory approach to explore resilience phenomena experienced by small unit members in the US Army. Participants were sampled from military occupational specialties within Combat Arms, as classified by the US Army Regimental System, and included members …

Analytic Methods For Geometric Modeling, Morad Behandish

Doctoral Dissertations

Current practice in mechanical product description and computational processing is rooted in the theory of solid modeling whose principles were established almost four decades ago. Despite providing a concrete foundation for computerizing the product development process at the time, the limited capacity of the traditional models to answer the growing design and manufacturing needs is only recently being recognized in the scientific and engineering communities.

I propose an alternative approach that employs spatial functions (i.e., 3D signals) instead of (or in addition to) topological pointsets in the Euclidean 3-space to abstract physical objects and their various geometric, physical, and material …

How Self-Efficacy Is Perceived By Urban High School Students, Patricia A. Decoster

Doctoral Dissertations

Academic self-efficacy, an individual’s judgement of his or her capacity to perform specific academic tasks, is described through a phenomenological study using interview, field notes and survey data. Academic self-efficacy is a main driver of motivation, stamina and resilience, qualities especially necessary within urban settings. The problem of practice is framed within the context of recent urban secondary structural reforms efforts to increase understanding of how students perceive their own self-efficacy as many studies in this area have been quantitative in nature and based on outcome indicators such as grades, attendance and graduation rates. Using a mixed methods convergent design, …

Real-Time Damage Detection For Civil Structures Using Big Data, Chenhao Jin

Doctoral Dissertations

The overall goal of the research in this dissertation is to develop efficient and accurate algorithms to detect damages in real time for civil structures using large scale of monitoring data. First, big data analysis is performed using one-year monitoring weigh-in-motion data collected from an in-service highway bridge located in Meriden, Connecticut. In order to quickly evaluate the structural condition from large scale of weight-in-motion data, two structural reliability-based methods were developed based on yield strength limit state and fatigue limit state. Then, in order to estimate structural parameter from structural dynamic response data, extended Kalman filter is used to …

Nonlinear Optical Processes For Spectral Broadening And Short Pulse Generation, Hongyu Hu

Doctoral Dissertations

The dramatic progress in optical communication is attributed to the development of wavelength-division multiplexing and time-division multiplexing technologies, which employ broadband light source and ultrashort optical pulses respectively to carry signals in optical fibers. Supercontinuum generation is the spectral broadening of narrow-band incident pulses by the propagation through optical waveguides made of nonlinear materials. In this PhD dissertation, I show the design of a tapered lead-silicate optical fiber for supercontinuum generation. The physical mechanisms of optical pulse evolution are explained, which involve various nonlinear optical effects including self-phase and cross-phase modulation, stimulated Raman scattering, four-wave mixing, modulation instability and optical …

Investigation On The Structural Variation Of Self-Assembled Lipid Bicellar Mixtures Upon Environmental Stimuli And Addition Of Pegylated Compounds, Ying Liu

Doctoral Dissertations

Bilayered mixed micelle, known as “bicelle”, has been extensively used as the biological membrane models in deciphering membrane-associated proteins. The bicellar mixtures normally constitute of long-chain and short-chain phospholipids in aqueous solutions. Disc-like morphology has been assumed for such mixtures where a bilayer fragment of long-chain phospholipids is sequestered by short-chain lipids at the rim.

Recently, other structures such as vesicles, elongated micelles, and lamellae have also been found in bicelles as temperature, concentration, and salinity vary.

The nano-sized bicellar discs (nanodiscs) and vesicles have great potential to be used as ingredient carriers for imaging and therapy. The research motivation …

Biophysics Of Dendritic Spine Morphogenesis, Olena Marchenko

Doctoral Dissertations

Dendritic spines receive the majority of synaptic inputs in the mammalian central nervous system and constitute the foundation for a healthy nervous system. Cognitive and motor delays, and other symptoms of impaired neurodevelopment are associated with abnormal dendritic spine shape and densities. Understanding of spine stability and spine formation in neurodevelopmental conditions remains elusive. Spine formation is determined by the stability of its transient precursor: the dendritic filopodium. First, we aim to understand dendritic filopodium motility and stability mechanism that underlies its transition into a spine. We hypothesized that mechanical feedback among the actin retrograde flow, myosin activity, and substrate …

Perception Of Administrators: Characteristics Of Effective Teachers In High-Poverty Secondary Schools And The Alignment Of These Characteristics With The Teacher Evaluation System, Toni Baggiano-Wilson

Doctoral Dissertations

The purpose of this study was to investigate the characteristics of an effective teacher in a high-poverty school as perceived by high school administrators and the alignment of these characteristics with the teacher evaluation system. School administrators identified the characteristics of an effective teacher in a high-poverty school. The characteristics of an effective teacher in a high-poverty school were compared with the teacher evaluation tool, EDUCATEAlabama. The comparison of the characteristics of effective teachers in high-poverty school with EDUCATEAlabama revealed the attributes of an effective teacher in a high-poverty school did not align with the state evaluation tool, EDUCATEAlabama …

Influence Of Moisture Content Distribution In Soil On Pavement And Geothermal Energy, Md Adnan Khan

Doctoral Dissertations

Moisture content in soil has a great implication in engineering design, and it has been heavily investigated by soil engineers and scientists. If moisture content in expansive soil changes drastically, it will create significant volume change in the soil. If expansive soil is present in building foundation or pavement subgrade, it may result in structural failure. On the other hand, if sufficient moisture content is present in soil, it will increase the production of geothermal energy from the ground soil. This dissertation is an effort to understand the effects of moisture content on both expansive soils and geothermal energy that …

A Study Of Mathematics Achievement, Placement, And Graduation Of Engineering Students, Sara Hahler Blazek

Doctoral Dissertations

The purpose of this study was to determine how background knowledge impacts freshmen engineering students' success at Louisiana Tech University in terms of grades in two different freshman classes and graduation. To determine what factors impact students, three different studies were implemented. The first study used linear regression to analyze which demographic and academic variables significantly impacted freshman math and engineering courses. Using regression discontinuity, the second study determined if the university's placement requirement for Pre-Calculus was appropriate. The final study analyzed factors that impact graduation for engineering students as well as other disciplines to determine which significant variables were …

Expanding The Applications Of Poly(Dimethylsiloxane) In Biomicrofluidics, Sawyer D. Stone

Doctoral Dissertations

This work aims to create novel applications for poly(dimethylsiloxane) (PDMS) in the field of biomicrofluidics through oxidative stress detection, doping of the polymer for intentional leaching into microdevices, and the development of low-cost implements for fabricating PDMS microfluidic devices. PDMS has become the polymer of choice for research in microfluidics due to its optical clarity, ease of fabrication, flexibility in design, good mechanical properties, and the ability to chemically modify the surface.

Biomicrofluidics enables the rapid throughput and analysis of small biological samples requiring less time investment and reagent use than traditional macroscale laboratory techniques. Polymer devices are inexpensive, easily …

The Mediating Influence Of Career Aspirations And Career Decision-Making Self-Efficacy On Self-Differentiation, Vocational Identity, And Career Indecision, Jay Justin Middleton

Doctoral Dissertations

Research indicates that numerous family variables influence the career-development process (Osipow, 1983). Bowen's family systems theory is one model through which to view the development and influence of the family on career development (Bowen, 1972). According to his theory, individuals begin life highly dependent on family members for all forms of support. As people grow into adults, they slowly become independent of their family, or self-differentiated. Adults low in self-differentiation have been found to make decisions in order to appease their families. Further, low levels of self-differentiation have been related to greater mental health problems (Skowron & Friedlander, 1998) and …

An Improved Imaging Method For Extended Targets, Sui Zhang

Doctoral Dissertations

The dissertation presents an improved method for the inverse scattering problem to obtain better numerical results. There are two main methods for solving the inverse problem: the direct imaging method and the iterative method. For the direct imaging method, we introduce the MUSIC (MUltiple SIgnal Classification) algorithm, the multi-tone method and the linear sampling method with different boundary conditions in different cases, which are the smooth case, the one corner case, and the multiple corners case. The dissertation introduces the relations between the far field data and the near field data.

When we use direct imaging methods for solving inverse …

Synthesis, Characterization, And Activity Of Co/Fe Alumina/Silica Supported Ft Catalysts And The Study Of Promoter Effect Of Ruthenium, Sunday Azubike Esumike

Doctoral Dissertations

The alumina and hybrid alumina-silica FT catalyst were prepared by one-step solgel/oil-drop methods using metal-nitrate-solutions (method-I), and nanoparticle-metaloxides (method-2). The nanoparticle-metal-oxides did not participate in solubility equilibria in contrast to metal nitrate in method-1 causing no metal ion seepage; therefore, method-2 yields higher XRF metal loading efficiency than method-1. The thermal analysis confirmed that the metal loading by method-1 and method-2 involved two different pathways. Method-1 involves solubility equilibria in the conversion of metal-nitrate to metal- hydroxide and finally to metal-oxide, while in method-2 nanoparticle-metal-oxide remained intact during sol-gel-oil-drop and calcination steps.

The alumina supported catalysts were dominated by γ-alumina …

Modeling And Observation Of He+ Pickup Ions In The Inner Heliosphere, Junhong Chen

Doctoral Dissertations

Interstellar pickup ions constitute a charged particle population that originates from interstellar neutrals inside the heliosphere. They are produced by photoionization, charge exchange with solar wind ions, and electron impact ionization (EI). Once ionized, they are picked up by the interplanetary magnetic field (IMF) and rapidly swept outward with the solar wind. Typically, pickup ion distributions have been described in terms of a velocity distribution function that evolves through fast pitch angle scattering followed by adiabatic cooling during radial transport in the reference frame of the solar wind [e.g., Vasyliunas & Siscoe, 1976, VS76 hereafter].

In the VS76 model, the …

A Beurling Theorem For Noncommutative Hardy Spaces Associated With A Semifinite Von Neumann Algebra With Various Norms, Lauren Beth Meitzler Sager

Doctoral Dissertations

We prove Beurling-type theorems for H-invariant spaces in relation to a semifinite von Neu-mann algebra M with a semifinite, faithful, normal tracial weight τ, using an extension of Arveson’s non-commutative Hardy space H-. First we prove a Beurling-Blecher-Labuschagne theorem for H-invariant subspaces of L p (M,τ) when 0 < p ≤ -. We also prove a Beurling-Chen-Hadwin-Shen theorem for H -invariant subspaces of L a (M,τ) where a is a unitarily invariant, locally k 1 -dominating, mutually continuous norm with respect to &\tau;. For a crossed product of a von Neumann algebra M by an action β, M o β Z, we are able to completely characterize all H-invariant subspaces of L a (Mo β Z,t) using our results. As an example, we completely characterize all H-invariant subspaces of the Schatten p-class, S p (H) (0 < p ≤ -), where H - is the lower tri-angular subalgebra of B(H). We also characterize the non-commutative Hardy space H -invariant subspaces in a Banach function space I(τ) on a semifinite von Neumann algebra M.

Student's Misconceptions Of Sequences And Series In Second Semester Calculus, David Earls

Doctoral Dissertations

Little is known about the difficulty students have with sequences and series in second semester calculus courses. In my dissertation, I investigate the misconceptions students had about sequences and series as they worked through problems typically seen in a second semester calculus course.

The dissertation begins with a rationale for studying student understanding of sequences and series. Next, I state my goals for the study as research questions. A conceptual framework is then developed for discussing student misconceptions in terms of an optimal concept map. Then, a three-phase methodology is given. In the first phase of the study, I collected …

A Dynamical-Systems Approach To Understanding Turbulence In Plane Couette Flow, Mimi Szeto

Doctoral Dissertations

Dynamical systems theory is used to understand the dynamics of low-dimensional spatio-temporal chaos. Our research aimed to apply the theory to understanding turbulent fluid flows, which could be thought of as spatio-temporal chaos in a very-high dimensional space. The theory explains a system's dynamics in terms of the local dynamics of its periodic solutions; these are the periodic orbits in state space. We considered the development of a model for the dynamics of plane Couette flow based on the theory. The proposed model is essentially a set of low-dimensional models for the local dynamics of the periodic orbits of the …

Music Of The Triangles: How Students Come To Understand Trigonometric Identities And Transformations, Neil Moshe Bornstein

Doctoral Dissertations

Trigonometry is an essential part of mathematics education (NCTM, 2000; NGA, 2010). Trigonometry is prevalent in studies of pure mathematics as well as physical applications. Trigonometric identities and transformations are particularly important. However, students and even teachers have struggled to articulate and justify trigonometric concepts (Moore, 2013; Tuna, 2013). Students have also struggled with identities and transformations in non-trigonometric contexts (Borba & Confrey, 1996; Tsai & Chang, 2009). This paper will describe a research project which articulates the critical stages through which students must pass to understand trigonometric identities and transformations. These critical stages were first hypothesized based on a …

Are 21st Century After School Programs An Effective Academic Intervention For Elementary School Students Attending High Poverty Schools?, Jennifer Scarpati

Doctoral Dissertations

In America, millions of children are living in poverty and/or attending high poverty schools. These students, on average, score lower on assessments of math and reading achievement than their more affluent peers. The federal government budgets money each year towards interventions targeted to raise the achievement of students living in poverty. 21st Century after school programs have received billions of dollars over the past 20 years towards this goal.

This is a secondary analysis of students attending five diverse, high poverty elementary schools in New Hampshire between 2008 and 2013. Ordinary Least Squares multiple regression analyses were used to estimate …

Edward Channing’S Writing Revolution: Composition Prehistory At Harvard, 1819-1851, Bradfield Edward Dittrich

Doctoral Dissertations

My dissertation, building on the work of John Brereton, Robert Connors, and others returns to the Harvard University Archives to reconstruct the Harvard rhetoric program under the leadership of Edward Tyrrel Channing from 1819 to 1851. During that time, coincident with the industrial revolution, U.S. publishers experienced a period of rapid growth as the cost of production for books, newspapers, and magazines dropped, and demand for print grew among a nascent middle class. Against that backdrop, and in spite of considerable resistance, Channing engineered a substantial shift at Harvard from an oratory-based curriculum to a writing-based one, just as the …

A Study Of Reconnection Poleward Of The Cusp: Cluster And Polar, Fathima M. Muzamil

Doctoral Dissertations

Asymmetries in plasma density and the presence of a guide field significantly alter the structure of the ion diffusion region (IDR) in symmetric, collisionless reconnection. These features have been shown by numerical simulations under moderate density asymmetries (~10), and theoretical analyses. However, very few studies have addressed these issues with in-situ observations, particularly at high magnetic latitudes. By the structure of the IDR we refer to features such as the non-colocation of the X-line and stagnation line, the distortion of the Hall magnetic and electric fields, outflow speed, outflow density etc. We have compiled a collection of Cluster crossings of …

Understanding Ion Spectral Dynamics Near The Inner Edge Of The Plasma Sheet, Cristian Ferradas

Doctoral Dissertations

The inner magnetosphere is a highly dynamic space environment in which particles strongly interact with the magnetic and electric fields. During the last few decades, several missions have recorded the presence of dynamic spectral features of energetic ions in in situ measurements, which represent the observational signatures of ion transport, acceleration, and loss in the inner magnetosphere. These ion spectral features constitute the inner extent of access of the plasma sheet to the low L values and play an important role in the dynamics of the inner magnetosphere, yet no statistical results of their species dependence are available to date. …

Statistical Properties And Applications Of Empirical Mode Decomposition, Mahdi Hameed Al-Badrawi

Doctoral Dissertations

Signal analysis is key to extracting information buried in noise. The decomposition of signal is a data analysis tool for determining the underlying physical components of a processed data set. However, conventional signal decomposition approaches such as wavelet analysis, Wagner-Ville, and various short-time Fourier spectrograms are inadequate to process real world signals. Moreover, most of the given techniques require \emph{a prior} knowledge of the processed signal, to select the proper decomposition basis, which makes them improper for a wide range of practical applications. Empirical Mode Decomposition (EMD) is a non-parametric and adaptive basis driver that is capable of breaking-down non-linear, …

Brauer-Picard Groups And Pointed Braided Tensor Categories, Costel Gabriel Bontea

Doctoral Dissertations

Tensor categories are ubiquitous in areas of mathematics involving algebraic structures. They appear, also, in other fields, such as mathematical physics (conformal field theory) and theoretical computer science (quantum computation). The study of tensor categories is, thus, a useful undertaking.

Two classes of tensor categories arise naturally in this study. One consists of group-graded extensions and another of pointed tensor categories. Understanding the former involves knowledge of the Brauer-Picard group of a tensor category, while results about pointed Hopf algebras provide insights into the structure of the latter.

This work consists of two main parts. In the first one we …