Physical Sciences and Mathematics Commons^™

Specific Phosphate Sorption Mechanisms Of Unaltered And Altered Biochar, Kathryn D. Szerlag

Masters Theses

Biochar has been shown to act as an effective sorbent for many organic and inorganic contaminants (including phosphate) and can help to improve the quality of our fresh water resources by preventing eutrophication. Most of the high efficiency biochar phosphate-adsorbent feedstocks are modified with chemical pretreatment, phytoremediation or anaerobic digestion to accumulate desired elements. The main objectives of this project were to first engineer magnesium (Mg) and calcium (Ca) altered biochar by chemical pretreatment followed by pyrolysis at either 350 or 550°C and evaluate their phosphate adsorption rate and potential as compared to their unaltered counterparts. Determination of surface physiochemical …

Fault Interaction Within Restraining Bend Fault Systems, Aviel Rachel Stern

Masters Theses

Numerical simulations of a 15° restraining bend analog claybox experiment include considering the fault geometry, rheology, and boundary conditions. The numerical models show that a growing fault from an analog experiment propagates at depth rather than at the surface and is exposed in later stages of the experiment, and that the wet kaolin clay from the analog experiment is partially decoupled from the steel plate. The numerical models provide the stresses to predict accurate fault growth from the analog experiment and provide the evolution of external work within the fault system. The external work from the numerical models decrease as …

Ecological Consequences Of Lost Anadromous Forage Fish In Freshwater Ecosystems, Steven R. Mattocks

Masters Theses

Beginning in the early 1600s, dam construction in New England obstructed anadromous fish access to spawning grounds during migration. As a result, anadromous forage fish populations have declined, which has impacted freshwater, marine, and terrestrial ecosystems. To determine the impacts of dams on anadromous forage fish and freshwater ecosystems, I used historical and current data to estimate population changes in alewives (Alosa pseudoharengus) from 1600-1900. A significant reduction in spawning habitat occurred in New England as a result of 1,642 dams constructed between 1600 and 1900, resulting in 14.8% and 16.6% lake and stream habitat remaining by 1900, …

Development Of Filter-Based Surface Enhanced Raman Spectroscopic Assays For Rapid Detection Of Chemical And Biological Contaminants In Water, Siyue Gao

Masters Theses

Surface enhanced Raman spectroscopy (SERS) has been widely applied for rapid and sensitive detection of various chemical and biological targets. Here, we incorporated a syringe filter system into the SERS method to detect pesticides, protein toxins and bacteria in water. For the detection of chemical and protein targets, silver nanoparticles (Ag NPs) were aggregated by sodium chloride (NaCl) to form nanoclusters that could be trapped in the pores of the filter membrane to from the SERS-active membrane. Then a coating of capture (e.g. aptamer) was integrated on the nanoparticle substrate if needed. Then samples were filtered through the membrane. After …

A Comparison Of Techniques For Handling Missing Data In Longitudinal Studies, Alexander R. Bogdan

Masters Theses

Missing data are a common problem in virtually all epidemiological research, especially when conducting longitudinal studies. In these settings, clinicians may collect biological samples to analyze changes in biomarkers, which often do not conform to parametric distributions and may be censored due to limits of detection. Using complete data from the BioCycle Study (2005-2007), which followed 259 premenopausal women over two menstrual cycles, we compared four techniques for handling missing biomarker data with non-Normal distributions. We imposed increasing degrees of missing data on two non-Normally distributed biomarkers under conditions of missing completely at random, missing at random, and missing not …

Factors Affecting Habitat Quality For Wintering Wood Thrushes In A Coffee Growing Region In Honduras, Brett A. Bailey

Masters Theses

Amongst the diversity of taxa that occur in the Neotropics, 200 migratory bird species that breed in temperate North America can be found. Many of these populations have seen significant declines since the 1960s. The Wood Thrush, Hylocichla mustelina, is one such species. Shade coffee and other agroforestry practices show potential for benefiting migratory species, but the quality of coffee habitat and optimal habitat characteristics for Wood Thrushes remain unknown.

I surveyed a spatially complex, agricultural landscape in Honduras outside the recognized winter range of the Wood Thrush and radio-tagged 46 individuals within rustic coffee farms during the winters …

Changing Sediment Transport Processes In Response To Anthropocene Forcing, Brian C. Yellen

Doctoral Dissertations

The denudation of uplands and sediment deposition within lowlands comprises one of the most fundamental earth processes. Much like plate tectonics or isostasy, sediment transport runs through nearly every geologic sub-discipline. Its importance extends to other fields as well, such as soil and plant science, archaeology, and engineering. Research in the field of sedimentology remains current, with changes in global sediment transport invoked as a primary line of evidence for the arrival of the Anthropocene, and sedimentary archives frequently employed to evaluate current processes relative to the past. In this vein, my doctoral studies have centered on understanding some aspects …

Geochemical Attributes Of Hydraulically Active Fractures And Their Influence On Groundwater Quality, Amy L. Hudson

Doctoral Dissertations

This study utilized discrete interval diffusion sampling of a fractured bedrock well completed in schist to investigate if a natural weathering signal can be used to identify hydraulically active fractures. The open borehole well MFS-1, is the focus of the study, which is in close proximity to the recharge zone making it ideal for testing the hypotheses of this study. The hydraulically active fractures of Well MFS-1 were identified, and the dominant mixing force of the water column of the well was determined to be thermal convection in the upper portion of the well and upward gradients. The isotopic data …

Morphological And Material Effects In Van Der Waals Interactions, Jaime C. Hopkins

Doctoral Dissertations

Van der Waals (vdW) interactions influence a variety of mesoscale phenomena, such as surface adhesion, friction, and colloid stability, and play increasingly important roles as science seeks to design systems on increasingly smaller length scales. Using the full Lifshitz continuum formulation, this thesis investigates the effects of system materials, shapes, and configurations and presents open-source software to accurately calculate vdW interactions. In the Lifshitz formulation, the microscopic composition of a material is represented by its bulk dielectric response. Small changes in a dielectric response can result in substantial variations in the strength of vdW interactions. However, the relationship between these …

Efficient Inference, Search And Evaluation For Latent Variable Models Of Text With Applications To Information Retrieval And Machine Translation, Kriste Krstovski

Doctoral Dissertations

Latent variable models of text, such as topic models, have been explored in many areas of natural language processing, information retrieval and machine translation to aid tasks such as exploratory data analysis, automated topic clustering and finding similar documents in mono- and multilingual collections. Many additional applications of these models, however, could be enabled by more efficient techniques for processing large datasets. In this thesis, we introduce novel methods that offer efficient inference, search and evaluation for latent variable models of text. We present efficient, online inference for representing documents in several languages in a common topic space and fast …

The Effect Of A Growing Black Hole On The Infrared Emission Of Dusty Galaxies In The Distant Universe, Allison Kirkpatrick

Doctoral Dissertations

The buildup of stellar and black hole mass peaked during z=1-3. Infrared (IR) luminous galaxies, which are massive and heavily dust obscured (L_IR > 10¹¹ L_sun), dominate the stellar growth during this era, and many are harboring a hidden active galactic nucleus (AGN). We have quantified the contribution of AGN heating to the infrared emission of a large sample of dusty, luminous galaxies from z=0.5-4 using Spitzer mid-IR spectroscopy, available for every source. We classify sources as star forming galaxies, AGN, or composites based on the presence of mid-IR continuum emission due to a dusty …

Hadron Physics In Tests Of Fundamental Symmetries, Chien Yeah Seng

Doctoral Dissertations

Low energy precision tests of fundamental symmetries provide excellent probes for the Beyond Standard Model Physics. Theoretical interpretations of these experiments often involve the application of non-perturbative Quantum Chromodynamics in the study of hadronic matrix elements that may either serve as signals of new physics or Standard Model backgrounds. In this work I present a series of studies on different hadronic matrix elements using various low-energy effective approaches to Quantum Chromodynamics, and discuss the impact of these studies on our knowledge of Standard Model and Beyond Standard Model physics.

Novel Analytical Methods Combining Non-Denaturing Chromatography And Mass Spectrometry To Study Biopolymer Structure And Interactions, Khaja Muneeruddin

Doctoral Dissertations

Biotherapeutics, an emerging class of medicines containing biopolymers (e.g., proteins, peptide, and polysaccharides) have been developed for a variety of indications including cancer, autoimmune, genetic, and blood diseases. Among these biopolymers protein therapeutics have been the rapidly growing segment in the pharmaceutical industry. This trend combined with the complexity of proteins has necessitated the development of powerful and robust analytical methods to study their structure and interactions with physiological partners. Mass spectrometry (MS) has become an indispensable tool to analyze various attributes of protein drugs such as profiling of intact mass, amino acid sequencing, and post translational modifications (PTMs). In …

Leveraging Backscatter For Ultra-Low Power Wireless Sensing Systems, Pengyu Zhang

Doctoral Dissertations

The past few years have seen a dramatic growth in wireless sensing systems, with millions of wirelessly connected sensors becoming first-class citizens of the Internet. The number of wireless sensing devices is expected to surpass 6.75 billion by 2017, more than the world's population as well as the combined market of smartphones, tablets, and PCs. However, its growth faces two pressing challenges: battery energy density and wireless radio power consumption. Battery energy density looms as a fundamental limiting factor due to slow improvements over the past several decades (3x over 22 years). Wireless radio power consumption is another key challenge …

Synthesis And Characterization Of Polymeric Anion Exchange Membranes, Wenxu Zhang

Doctoral Dissertations

As alkaline anion exchange membrane fuel cells (AAEMFC) are regarded as promising and important energy devices, the development of high performance anion exchange membranes are in urgent need, as well as fundamental investigation on the structure-property relationship, which are the motivation of this dissertation. Three different polymer systems are presented and focused on polymer synthesis, material morphology, and ion transport phenomena. Crosslinked membranes are promising as practical materials, however, the understanding and further improvement of its performance is hindered by the lack of an ordered morphology or well-defined chemical structure. In Chapter 2, a series of crosslinked membranes were design …

Wind Farm Wake Modeling And Analysis Of Wake Impacts In A Wind Farm, Yujia Hao

Doctoral Dissertations

More and more wind turbines have been grouped in the same location during the last decades to take the advantage of profitable wind resources and reduced maintenance cost. However wind turbines located in a wind farm are subject to a wind field that is substantially modified compared to the ambient wind field due to wake effects. The wake results in a reduced power production, increased load variation on the waked turbine, and reduced wake farm efficiency. Therefore the wake has long been an important concern for the wind farm installation, maintenance, and control. Thus a wake simulation tool is required. …

Neoarchean Arc Magmatism, Subsequent Collisional Orogenesis, And Paleoproterozoic Disruption Within The Western Churchill Province: Implications For The Growth And Modification Of Lower Continental Crust, Sean P. Regan

Doctoral Dissertations

The growth and modification of continental lithosphere are fundamental geologic processes that have had a profound effect on Earth’s evolution. The lower continental crust can play a myriad of roles pertaining to these processes depending on the strength, age, temperature, and composition of the rocks present. However, the lower continental crust is impossible to sample in-situ, and thus observations of modern lower continental crust are limited to seismic studies and xenolith studies, which provide mere snap shots of the lower crust. High pressure granulite terranes provide 4 dimensional, and spatially resolvable, analogues of lower continental crust. The Athabasca granulite terrane …

Photolysis Of Triazenylbenzoic Acids For Click Chemistry, Adam Gann

Doctoral Dissertations

Copper catalyzed cycloaddition of terminal alkynes and azides has revolutionized the field of bioconjugate chemistry. Unfortunately, typical copper catalysts are known to disrupt relevant biological systems, so it has become necessary to develop new, copper-free methods that are less cytotoxic. particular interest are "click" probes which can be activated with an outside light source, giving the user spatial and temporal control over the system being investigated. We have developed a method in which an aryl diazonium salt is rapidly generated using photolysis of the triazene functional group, and subsequently coupled with an electron rich aromatic nucleophile to yield an azobenzene. …

Magnetic Doping Of Semiconductor Molecular Models And Colloidal Nanocrystals, Swamy Pittala

Doctoral Dissertations

Spin-based electronics use the spins of electrons in addition to their charges and have potential applications to create a next generation of quantum computers, capable of storing vast amounts of data in an energy-efficient way. Diluted magnetic semiconductor quantum dots (DMS-QDs) have shown great promise as ideal materials for application in spin-based electronics. However, doping impurities into quantum confined colloidal nanocrystals (NCs) has been a great challenge due to the lack of control over the dopant reactivity during the specific stages of nucleation and growth. The mechanism of dopant incorporation into nanocrystals is complex and well-defined and atomically precise molecular …

Ocean Gateways And Glaciation: Planktic Foraminiferal Records From The Southern Ocean, Equatorial Pacific, And Caribbean, Andrew J. Fraass

Doctoral Dissertations

Ocean gateway changes, once the best mechanism for driving abrupt climatic change, have fallen from favor. They have been largely replaced within the literature by changes in CO₂ concentration and orbital forcing. This dissertation looks at three intervals of relative stability (Oligocene), prolonged change (Plio-Pleistocene), or transient events (Oligocene/Miocene boundary) in order to better understand the oceanographic circumstances which govern ‘events’ in the paleoceanographic record. Chapter 1 discusses the chronostratigraphy of Integrated Ocean Drilling Program (IODP) Site U1396 (Expedition 340) in the Caribbean Sea. A combination of paleomagnetostratigraphy, biostratigraphy, astrochronology, and correlation to Marine Isotope Stages (MIS) allows a …

Kinetic And Dynamic Insights Into The Substrate Interactions And Catalysis Of Factor Inhibiting Hif-1 (Fih-1), Cristina B. Martin

Doctoral Dissertations

inhibiting HIF-1 (FIH-1) modulates the master regulator of hypoxia sensing, hypoxia inducible factor-1 (HIF-1), by transcriptional repression making it an attractive potential target for treatment of hypoxia-related diseases. Given that similar enzymes are present within the cell and that they have other important physiological roles, defining the therapeutic window by which it can be selectively targeted becomes an issue. Consequently, it’s necessary to have a deeper understanding of the substrate interactions in FIH-1 that contributes to catalysis as this is one avenue that can be explored for future therapeutic investigations. The overall goal of this dissertation is to gain kinetic …

Restoration: Bridging The Gaps A Graphic Translation Of Ecological Restoration, Alyssandra Black

Masters Theses

The terms restoration ecology and ecological restoration are used interchangeably confusing the definition and work of ecological restoration and its many components. Restoration ecology is a type of scientific practice whose work will be a component of a restoration project while ecological restoration is the sum of practices, social, historical and ecological that constitute the field of restoration (Higgs, 2005). Within our rapidly urbanizing society the role of ecological restoration and restoring ecosystem services is increasingly important, especially within our coastal cities. The goals of restoration differ when the classification of restoration techniques is by ecosystem service, not ecological function, …

Sleep Patterns, Urinary Levels Of Melatonin And Subsequent Weight Change In The Women’S Health Initiative Observational Study, Nicole M. Barron

Masters Theses

Results from prospective studies examining associations between sleep duration and weight gain have been mixed. Melatonin has been hypothesized to mediate the association between sleep duration and weight/body composition. In cross-sectional studies, aMT6s has been shown to be inversely associated with weight/body fat percentage. We examined associations between baseline sleep duration, insomnia status, aMT6s levels with weight/body fat percentage through 6 years, utilizing a subset 690 women who participated in a breast cancer case-control study nested within the WHI-OS. Multi-variable and mixed-effects regression was used to calculate beta-coefficients and 95% confidence intervals. Cross-sectional analyses showed urinary aMT6s levels were inversely …

Extending Faceted Search To The Open-Domain Web, Weize Kong

Doctoral Dissertations

Faceted search enables users to navigate a multi-dimensional information space by combining keyword search with drill-down options in each facets. For example, when searching “computer monitor”' in an e-commerce site, users can select brands and monitor types from the the provided facets {“Samsung”, “Dell”, “Acer”, ...} and {“LET-Lit”, “LCD”, “OLED”, ...}. It has been used successfully for many vertical applications, including e-commerce and digital libraries. However, this idea is not well explored for general web search in an open-domain setting, even though it holds great potential for assisting multi-faceted queries and exploratory search. The goal of this work is to …

Nanomaterials At Liquid/Liquid Interfaces: Assembly And Rheology, Tao Feng

Doctoral Dissertations

This dissertation concentrated on the behavior of nanomaterials at liquid/liquid interfaces. A strategy of segregating acid-treated SWCNTs at oil/water interfaces was developed by adding amine-terminated polystyrene (PS-NH₂) in the oil phase. Electrostatic binding between carboxylic acid of SWCNTs and amine drives the assembly of SWCNTs, monitored by pendant drop tensiometry and confocal microscopy. A sharp transition of interfacial segregation against SWCNT solution pH was revealed, with the transition point at the pKa of carboxyl. The reduced SWCNT surface charge density at low pH was found to be beneficial for segregation due to the attenuated repulsions between adsorbed …

Design, Synthesis, And Applications Of Nano-Assemblies Based On Amphiphilic Macromolecules, Hui Wang

Doctoral Dissertations

Recent progress in nanotechnology has been significantly impacting a variety of areas such as utilization in microelectronics, multiphase catalysis, sensing and therapeutics. Our interests are to develop new nanomaterials to understand their structure-property relationships and to utilize them for various applications. In this thesis, we discuss our findings on the design, synthesis and applications of nanomaterials formed by self-assembly of amphiphilic molecules. Micelles are self-assembled nanostructures formed by amphiphilic molecules. They are capable of sequestering hydrophobic guest molecules in an aqueous environment. Other than surfactants, micelles can also be formed by amphiphilic polymers or dendrimers, which are macromolecular surfactants in …

Effective Performance Analysis And Debugging, Charles M. Curtsinger

Doctoral Dissertations

Performance is once again a first-class concern. Developers can no longer wait for the next generation of processors to automatically "optimize" their software. Unfortunately, existing techniques for performance analysis and debugging cannot cope with complex modern hardware, concurrent software, or latency-sensitive software services. While processor speeds have remained constant, increasing transistor counts have allowed architects to increase processor complexity. This complexity often improves performance, but the benefits can be brittle; small changes to a program’s code, inputs, or execution environment can dramatically change performance, resulting in unpredictable performance in deployed software and complicating performance evaluation and debugging. Developers seeking to …

Algebraicity Of Rational Hodge Isometries Of K3 Surfaces, Nikolay Buskin

Doctoral Dissertations

Consider any rational Hodge isometry $\psi:H^2(S_1,\QQ)\rightarrow H^2(S_2,\QQ)$ between any two K\"ahler $K3$ surfaces $S_1$ and $S_2$. We prove that the cohomology class of $\psi$ in $H^{2,2}(S_1\times S_2)$ is a polynomial in Chern classes of coherent analytic sheaves over $S_1 \times S_2$. Consequently, the cohomology class of $\psi$ is algebraic whenever $S_1$ and $S_2$ are algebraic.

Who Is Like Whom? Reclassification And Performance Patterns For Different Groupings Of English Learners, Molly M. Faulkner-Bond

Doctoral Dissertations

Approximately 10 percent of the US K-12 population consists of English learners (ELs), or students who are learning English in addition to academic content in areas like English language arts (ELA) and mathematics. In addition to meeting the same academic content and performance standards set for all students, it is also a goal for ELs to be reclassified – i.e., to master English so that they can shed the EL label and participate in academic settings where English is used without needing special support. Working with a longitudinal cohort of ~28,000 ELs in grades 3 through 8 from one state, …

A Paleobathymetric Model And Evolution Of The Brazilian Marginal Basins During The Late Maastrichtian To Eocene Based On Benthic Foraminiferal Biofacies, Renata Moura De Mello

Doctoral Dissertations

Benthic foraminiferal biofacies were delimited for the Maastichtian to upper Eocene of five Brazilian marginal basins (Sergipe-Alagoas, Mucuri, Campos, Santos and Pelotas) and two DSDP Sites 356 and 20C of the western South Altantic. Five biofacies, denoted with letters A to E, were defined using Q-mode cluster analysis and correspondence analysis for all of the 11 sites. The benthic foraminiferal biofacies were used to establish a paleobathymetric and paleoenvironmental model for the Brazilian marginal basins. The model tracks the evolution of the margin as it built seaward and transitioned from abyssal (2000-3000 m) to bathyal (m) and neritic (m) depositional …