Physical Sciences and Mathematics Commons^™

Electron Beam Characterization Of Carbon Nanostructures, Eric Samuel Mandell

Dissertations

Atom-thick carbon nanostructures represent a class of novel materials that are of interest to those studying carbon's role in fossil fuel, hydrogen storage, scaled-down electronics, and other nanotechnology. Electron microscope images of "edge-on" graphene sheets show linear image features due to the projected potential of the sheets. Here, intensity profiles along these linear features can measure the curvature of the sheet, as well as the shape of the sheet (i.e. hexagonal, triangular). Also, electron diffraction powder profiles calculated for triangular graphene sheet shapes show a broadening of the low-frequency edge of diffraction rings, in comparison to those calculated for hexagonal …

What Allows Teachers To Extend Student Thinking During Whole-Group Discussions, Nesrin Cengiz

Dissertations

Research indicates that extending students' mathematical thinking during whole-group discussions is challenging, even for the most experienced teachers. That is, it is challenging for teachers to help students move beyond their initial mathematical observations and solutions during whole-group discussions. To better understand this phenomena, the teaching of six experienced elementary school teachers, who had been teaching aStandards-based curriculum for several years and had participated in a multi-year professional development project focused on that curriculum, is explored in this study. In particular, two issues are addressed: what it looks like to extend student thinking during whole-group discussions and how …

Structure And Excitations In Metal Ammonia Compounds, Xue Wang

Dissertations

This work has two parts. In the first part, inelastic x-ray scattering was used to measure the plasmon excitations in liquid lithium ammonia systems. The measurements were carried out for different metal concentrations, 8 mole per metal (MPM), 10 MPM, 11 MPM, 16 MPM and 20 MPM of temperature 200K. The data were analyzed to determine the plasmon energy and the linewidth as a function of momentum for each metal concentration. Deviations from the random phase approximation (RPA) in the jellium model increase as the concentration is lowered.

In the second part of this work, elastic x-ray scattering was used …

Adsorption Of Lead On Single And Mixed Solid Systems, Soumya Das

Dissertations

Metal oxy-hydroxides and phyllosilicate minerals play a significant role in the fate and transport of heavy metals in the environment (Bertsch and Seaman, 1999). Chemical speciation of metals affects their bioavailability and chemical reactivity (Stumm and Morgan, 1996). Surface complexation models (SCMs) based on equilibrium thermodynamic principles have been successfully used to quantify adsorption of heavy metals on pure solid minerals, including phyllosilicates and oxy-hydroxides. For natural sediments with mixed mineralogy, Davis et al. (1998) suggested two different SCM approaches, namely, the component additivity and generalized composite models. In this study, adsorption of lead on pure HFO, silica and kaolinite …

Quantum Properties Of Light Emitted By Dipole Nano-Laser, Talal Ghannam

Dissertations

Recent technological advances allow entire optical systems to be lithographically implanted on small silicon chips. These systems include tiny semiconductor lasers that function as light sources for digital optical signals. Future advances will rely on even smaller components. At the theoretical limit of this process, the smallest lasers will have an active medium consisting of a single atom (natural or artificial). Several suggestions for how this can be accomplished have already been published, such as nano-lasers based on photonic crystals and nano wires. In particular, the "dipole nanolaser" consists of a single quantum dot functioning as the active medium. It …

Synthesis, Study Of Self-Assembly, And Trivalent Lanthanide Metal Ion Recognition Characteristics Of Amphiphilic Acylpyrazolones And Amphiphilic Acylisoxazolones, Venkat Reddy Guduru

Dissertations

This research project focused on the separation of trivalent lanthanide metal ions by HPLC using amphiphilic acylpyrazolones and amphiphilic acylisoxazolones. The central hypothesis of our research project is that the nanoscale self-assembly nature of amphiphilic ligands (chelating lingads) can influence their metal ion recognition and separation. To test the central hypothesis, we have synthesized a family of novel amphiphilic ligands and employed them as model systems for the separation of trivalent lanthanide metal ions. Several novel intermediates such as 4-acylated. N -acylated, O -acylated pyrazolones and isoxazolones, have been efficiently synthesized and fully characterized.*

The trivalent lanthanide metal ion recognition …

Diagnostics For Choosing Between Log-Rank And Wilcoxon Tests, Ruvie Lou Maria Custodio Martinez

Dissertations

Two commonly used tests for comparison of survival curves are the generalized Wilcoxon procedure of Gehan (1965) and Breslow (1970) and the Log-rank test proposed by Mantel (1966) and Cox (1972). In applications, the Log-rank test is used after checking for validity of the proportional hazards (PH) assumption, with Wilcoxon being the fallback method when the PH assumption fails.

However, the relative performance of the two procedures depend not just on the PH assumption but also on the pattern of differences between the two curves. We will show that the crucial factor is whether the differences tend to occur early …

Extensions Of Two-Part Tests To Compare K Independent Populations, Marwan Daoud

Dissertations

We consider two-part models that are mixtures of a point-mass variable with all mass at zero and a continuous random variable. The model may assume a particular distributionh(x) for the continuous part such as a log-normal or a gamma. The response variable is defined as y=(x, d), where d=1 if x > 0 and d=0 if x = 0. The probability distribution function has the following form: fx,d=p ^1-d×1-p ×hx ^d.

Lachenbruch (1976, 2001) proposed several tests to compare means of two populations for this type of data. We proposed a two-part Wald test and …

Synthesis And Characterization Of Stilbenoids And Their Aza-Analogs As Photoluminescent Materials For The Detection Of Nerve Agent Mimics, Chun Wang

Dissertations

A novel series of stilbenoids and their aza analogs were synthesized, characterized and used as photoluminescent components in the detection of nerve agents. Their structure-property relationship was elucidated through UV-visible and fluorescence spectroscopy. The research in this thesis is driven by the hypothesis that the two-block sensor system consisting of a receptor incorporated ruthenium complex and a fluorescent signal molecule of stilbenoids, is capable of detecting chemical warfare agents. The sensor anchored onto nanoparticles and subsequently the nanoparticles were arranged through mediated self-assembly. While photo-induced electron transfer is a well-known mechanism for sensor design, the described system showed that photo-induced …

Mobile Information Communication Technology For Crisis Management : Understanding User Behavior, Response And Training, Elizabeth Avery Gomez

Dissertations

SMS text-messaging is an interoperable communication vehicle known to be dependable for mass media alert notifications in crisis management. SMS text-messaging also offers potential as one viable two-way communication alternative for field responders in crisis response. Both continuously changing mobile information communication technologies and the importance of precise information exchange constitute a need for communication protocol training and practice. This study introduces a technology-mediated training technique based on speech act and communicative action theories. These theories are used to inform the design of a baseline measure for task performance improvement and to suggest a model to predict communication readiness. Because …

Design And Application Of Near Infrared Tunable Filter For Atst And Nst, Jun Ma

Dissertations

This thesis includes the following sections: a general design of the Near Infrared Tunable Filter (NIRTF) of Advanced Technology Solar Telescope (ATST) project and the Near Infrared Imaging Magnetograph (IRIM) of the New Solar Telescope (NST), the design of achromatic waveplates, the narrowband continuum observation of a Sunspot at 1.56 µm using IRIM instruments, and the coronal hole observation using the Digital Vector Magnetograph (VMG) at Big Bear Solar Observatory (BBSO).

A near infrared tunable filter system is designed with detailed optical parameters for each component in the system. Among these components, the achromatic waveplates, which used to be an …

Designing Multimodal Interaction For The Visually Impaired, Xiaoyu Chen

Dissertations

Although multimodal computer input is believed to have advantages over unimodal input, little has been done to understand how to design a multimodal input mechanism to facilitate visually impaired users' information access.

This research investigates sighted and visually impaired users' multimodal interaction choices when given an interaction grammar that supports speech and touch input modalities. It investigates whether task type, working memory load, or prevalence of errors in a given modality impact a user's choice. Theories in human memory and attention are used to explain the users' speech and touch input coordination.

Among the abundant findings from this research, the …

Interaction Of Methoxyethyl Methyl Imidazolium-Based Ionic Liquids With Uranium And Its Effect On Bioreduction Of Uranium, Hao Wang

Dissertations

Ionic liquids (ILs) are new materials with unique properties such as non-measurable vapor pressure, low melting point below 100°C and tunable physical-chemical properties. These liquids demonstrate tremendous potential applications in many fields, including nuclear waste treatment.

In this study, new MOEMIM (methoxyethyl methyl imidazolium)-based ionic liquids were synthesized. Their properties were characterized by UV-Vis spectroscopy (UV-vis), Fourier transform infrared spectroscopy (ETIR), mass spectroscopy (MS) and NMR (Nuclear magnetic resonance). The interaction between ILs and uranium has been explored by various analysis techniques, including pH, potentiometric titration, UV-vis, MS and EXAFS (extended x-ray absorption fine structure). Among all the ILs studied …

Design And Implementation Of Split Tcp In The Linux Kernel, Rahul Jain

Dissertations

The Transmission Control Protocol (TCP) was designed for reliable communication between computers over networks of unpredictable quality. It has admirably succeeded in satisfying the needs of the growing internet. Yet, there are combinations of network problems too bad even for TCP. In particular, in the situation of simultaneously very high delay (e.g. a satellite link) and high loss or even fading (a low quality earthlink or wireless link) on the same connection TCP can break down.

A known solution is “Split TCP” where one or more proxies (called Helper Boxes) are introduced to break the end-to-end connection into few (almost) …

Solar Activity Detection And Prediction Using Image Processing And Machine Learning Techniques, Gang Fu

Dissertations

The objective of the research in this dissertation is to develop the methods for automatic detection and prediction of solar activities, including prominence eruptions, emerging flux regions and solar flares. Image processing and machine learning techniques are applied in this study. These methods can be used for automatic observation of solar activities and prediction of space weather that may have great influence on the near earth environment.

The research presented in this dissertation covers the following topics: i) automatic detection of prominence eruptions (PBs), ii) automatic detection of emerging flux regions (EFRs), and iii) automatic prediction of solar flares.

In …

Design, Fabrication And Testing Of A Fiber Optic Stress/Strain Sensor For Soft Stretchable Materials Using Polarization Imaging Technique, Jianjun Zheng

Dissertations

The polarization imaging technique has been used to obtain high quality surface images of turbid media. This technique can be slightly modified and used for noninvasive sensing of strain and stress in soft stretchable materials, such as latex and human tissues. Previously this sensing method was developed with free space bulk optics. In this study, a fiber optic based system is developed to investigate the potential application of this technology on the strain/stress as well as surface roughness measurements of stretchable materials. In this system, polarizers are simply attached to the fiber ends to form a polarizing three-fiber probe. Furthermore, …

Modified Fenton Oxidation Of Hydrocarbon Contaminated Soils With Cao2: Microbial Survival And Surfactant Production, Abraham Matthew Northup

Dissertations

The efficacy of CaO₂ for use in modified Fenton's (MF) reactions was investigated in this study, with the goal of developing a CaO₂-based MF oxidation technology for use in in situ chemical oxidation. Traditionally, liquid H₂O₂ (HP) is used, and is injected into the subsurface in excess to ensure a sufficient radius of influence. CaO₂ was investigated as an alternative source of H₂O₂ for MF reactions.

First, the rate of dissolution of powdered CaO₂ and the yield of HP was investigated. Our results showed that the rate of dissolution …

The Effect Of Chloramphenicol On Bb88 Murine Erythroleukemia Cells, Peter K. W. Harris

Dissertations

DNA microarrays can be used to measure genome-wide transcript levels. These measurements may be useful in understanding cellular changes induced by a chemical agent. In this study, Affymetrix microarray technology has been used to study the effects of chloramphenicol, an antibiotic that inhibits bacterial and mitochondrial protein synthesis, on the transcription profile in mammalian cells. Transcript levels in BB88 murine erythroleukemia cells treated with 50 micromolar ( mu M) chloramphenicol, a concentration shown to inhibit BB88 proliferation, are measured. Using total RNA from treated cells, biotin-labeled cRNA was prepared and hybridized to Affymetrix U74Av2 microarrays. From these hybridizations, expression levels …

Wireless Passive Surface Acoustic Wave (Saw) Sensing System, Sridevi Krishnamurthy

Dissertations

Due to their small size and ruggedness, Surface Acoustic Wave (SAW) devices have been widely used as part of wireless sensing or identification system especially in inaccessible and inhospitable environments. In addition, SAW devices find widespread applications as filters in communication systems and also as physical, chemical and bio-sensors and ID tags. The passive wireless SAW sensing system mainly consists of a passive SAW sensor and an interrogation unit which sends a burst signal to the SAW sensor and processes the sensor response. Theobjectives of this work were designing, prototyping and fabricating the interrogation unit on a PCB and also …

Some Applications Of Gaussian Quadrature And Neural Network Modeling In Earth Flows And Other Slow-Moving Landslides In Cohesive Slope Materials, Rennie Bwalya Kaunda

Dissertations

Geometrical changes and progressive displacements in earth flows and other slow moving landslides triggered by climatic changes may be addressed by digital modeling. Gaussian quadrature, a numerical integration technique though fixed points, is employed to compute geometrical areas defined by stratigraphic (soil or rock layering) units, vertical pole projections and a slip surface, based on kinematic admissibility. An example from the Lake Michigan coast shows that the total internal geometrical area is found to be preserved during the course of the progressive deformation. Displacement monitoring of the slope shows that it became less stable over a period of eleven years …

The Fock Space And Related Bergman Type Integral Operators, Ovidiu Furdui

Dissertations

In this thesis we study the boundedness of a general class of integral operators induced by the kernel functions of Fock spaces. More precisely, for a, b, and c real parameters we study the action of [Special characters omitted.] and [Special characters omitted.] on Lp ([Special characters omitted.] ,dv_s ), where dv_s ( z ) = [Special characters omitted.] is the Gaussian probability measure on [Special characters omitted.] . We prove that, when p > 1, respectively p = 1, these operators are bounded if and only if p satisfies a quadratic, respectively a linear, inequality. The …

Measures Of Travers Ability In Graphs, Futaba Okamoto

Dissertations

For a connected graph G of order n ≥ 3 and a cyclic ordering sc : v 1, v2,..., vn, v n+1 = v1 of vertices of G, the number d(sc) is defined by d(sc) = i=1n d(vi, vi +1), where d(vi, vi +1) is the distance between vi and vi+1 in G for 1 ≤ i ≤ n. The Hamiltonian number h(G) and upper Hamiltonian number h +(G) of G are defined as h(G) = min{d(sc)} and h+(G) = max{d(sc)}, respectively, where the minimum and maximum are taken over all cyclic orderings s c of vertices of G. For …

A New Model For Cooperative Mobility In Support If Qos In Manets With Heterogeneous Autonomy Requirements, Ghassen Ben Brahim

Dissertations

Modern mobile ad-hoc networks (MANETs) frequently consist of nodes which exhibit a wide range of autonomy needs. This is particularly true in the settings where MANETs are model compelling, i.e. battlefield, response & rescue, and contexts requiring rapid deployment of mobile users. The time-critical nature of the underlying circumstances frequently requires deployment of both manned and unmanned nodes, and a coordination structure which provides prioritized tasking to them.

In classic ad-hoc networks settings, it is assumed that all nodes are autonomous and do not depend in any case on other nodes. In this research work, contrarily to this design, we …

The Global Hepatic Transcriptional Response Of Male Fisher Rats To Dietary Aroclor 1254 Exposure, Trisha M. Basford

Dissertations

Dietary intake is a primary route for biomagnification of environmentally persistent polychlorinated biphenyls (PCBs) within humans and animals. Aroclor 1254, a mixture of PCBs, is associated with a variety of toxic responses including alterations in blood and lipid biochemistry and tumor promotion. Measurement of the transcriptional responses to low-level dietary exposure to A1254 has not been reported to date, and is important given the persistence of PCBs, and range of effects associated with exposure. The aims of this study were to characterize changes in rat hepatic global gene expression due to sub-acute and sub-chronic dietary exposure to A1254, and to …

Inelastic X-Ray Scattering Studies On Organic Semiconductors And Organic Superconductors, Chaminda Nalaka Kodituwakku

Dissertations

We have measured electronic excitations and excitons in CuPc polycrystalline and single crystal samples. Measurements on the polycrystalline sample were done with 300 meV resolution and measurements on the single crystal were done using 120 meV resolution. Time dependant density functional theory (TD-DFT) calculations were done on the CuPc molecule to understand the electronic excitations in this system.

Laboratory Based Chemical And Isotopic Investigations On Biotic (Microbial) And Abiotic Reduction Of Iron And Oxidation Of Organic Compounds, Tsigabu Asmelash Gebrehiwet

Dissertations

Studies using chemical and isotopic techniques have been conducted to investigate experimental microbial (biotic) iron reduction and abiotic redox processes. In the microbially mediated study Fe(III) reduction and lactate oxidation at circum-neutral pH and anaerobic conditions were used to characterize the metabolic pathways followed by dissimilatory Fe⁺³ -reducing bacterium Shewanella putrefaciens strain 200R. Iron (II), Iron (III), dissolved inorganic carbon (DIC) and carbon isotope ratios were measured under bicarbonate and phosphate buffered conditions. Carbon isotope disproportionation among organic carbon substrate (lactate), biomass and respired carbon dioxide at the lag to stationary phase of the microbial growth curve showed …

Problems Related To Efficacy Measurement And Analyses, Sibabrata Banerjee

Dissertations

In clinical research it is very common to compare two treatments on the basis of an efficacy variable. More specifically, if X and Y denote the responses of patients on the two treatments A and B, respectively, the quantity P(Y>X) (which can be called the probabilistic index for the Effect Size), is of interest in clinical statistics. The objective of this study is to derive an efficacy measure that would compare two treatments more informatively and objectively compared to the earlier approaches. Kernel density estimation is a useful non-parametric method that has not been well utilized as an applied …

Prediction Of Mrna Polyadenylation Sites In The Human Genome And Mathematical Modeling Of Alternative Polyadenylation, Yiming Cheng

Dissertations

Messenger RNA (mRNA) polyadenylation plays many important roles in the cell, such as transcription termination, mRNA stability and transportation, and mRNA translation in eukaryotic cells. A large number of human and mouse genes have multiple polyadenylation sites (referred to as poly(A) sites) that lead to variable transcripts, some of which are translated into various protein products with different functions. However, the details about when and where the polyadenylation occurs, and how pre-mRNA switches from one poly(A) site to another are still unknown. This kind of 3 '-end processing can be regulated by the cell environment, cell cycle stage, and tissue …

People-Search : Searching For People Sharing Similar Interests From The Web, Quanzhi Li

Dissertations

On the Web, there are limited ways of finding people sharing similar interests or background with a given person. The current methods, such as using regular search engines, are either ineffective or time consuming. In this work, a new approach for searching people sharing similar interests from the Web, called People-Search, is presented. Given a person, to find similar people from the Web, there are two major research issues: person representation and matching persons. In this study, a person representation method which uses a person's website to represent this person's interest and background is proposed. The design of matching process …

Sifting Customers From The Clickstream : Behavior Pattern Discovery In A Virtual Shopping Environment, Peishih Chang

Dissertations

While shopping online, customers' needs and goals may change dynamically, based on a variety of factors such as product information and characteristics, time pressure and perceived risk. While these changes create emergent information needs, decisions about what information to present to customers are typically made before customers have visited a web site, using data such as purchase histories and logs of web pages visited. Better understanding of customer cognition and behavior as a function of various factors is needed in order to enable the right information to be presented at the right time. One approach to achieving this understanding is …