Physical Sciences and Mathematics Commons^™

Synthesis And Characterization Of Polymeric Materials Derived From Multifunctional Alkyl A-Hydroxymethylacrylates, Jean-Francois Morizur

Dissertations

The research presented in this dissertation covers the investigation of new materials derived from alkyl a-hydroxymethylacrylates (RHMA). The first project exposed in Chapter II involves the synthesis, characterization of RHMA-based reactive surfactants and their successful incorporation in acrylic latexes. The amphiphilic monomers testify of a good copolymerization behavior with other acrylic monomers such as methyl methacrylate and butyl acrylate although their extensive bulkiness. They led to the formation of well-defined polymeric particles via a seeded emulsion polymerization process and permitted decreasing significantly the water sensitivity of the resulting films as compared to film incorporating conventional emulsifier such as sodium dodecyl …

Raft Synthesis Of Water-Soluble, Stimuli-Responsive Ab Diblock Copolymers, Ran Wang

Dissertations

A series of water-soluble, stimuli-responsive AB diblock copolymers were synthesized via the reversible addition-fragmentation chain transfer (RAFT) polymerization technique employing 2-(2- carboxyethylsulfanylthiocarbonylsulfanyl)propionic acid (CTA26) as the RAFT mediating agent.

First, a series of diacid functional trithiocarbonate chain transfer agents (CTA's) were synthesized and examined for their effectiveness as mediating agents in controlling the polymerization of «-butyl acrylate (nBA). Overall, CTA26 demonstrated good control in the homopolymerization of nBA with respect to the molecular weight and the molecular weight distribution, as well as its ability to form block copolymers with high reinitiating efficiency, and thus was chosen as the CTA for …

Interactive Visual Exploration Of Large Relation, Mustafa Sanver

Dissertations

As data become ubiquitous and immense in many activities from business decision making to scientific analysis, effective analysis of such data becomes an important research area. Data analysis requires active involvement of human beings and visualization is a powerful tool to capture profound insights from data. However, interactive visual exploration of massive data poses fundamental technical challenges to both data visualization and database management systems. Millions of billions of data records clutter the screen and existing database management systems are inadequate for overview-and-drill-down data access for interactive data exploration.

We have proposed a density-based methodology to address the above challenge. …

The Role Of Prediction In The Teaching And Learning Of Algebra, Lisa Kasmer

Dissertations

Research has shown that including prediction questions within reading and science instruction has been advantageous for students, yet minimal research existed regarding the use of such questions within mathematics instruction. In order to extend and build on our knowledge about the effects of prediction in mathematics instruction, this study explored the impact of this paradigm in the teaching and learning of algebra. Specifically, this study probed whether utilizing prediction questions provided students opportunities for engaging in mathematical thinking, retrieving prior knowledge, and discussing related mathematical ideas, could increase such students' conceptual understanding and mathematical reasoning in the content area of …

A Proof Of Concept For Oppnets And Its Resource Utilization Techniques With Qos Constraints, Zill-E-Huma Kamal

Dissertations

The increased number of embedded devices/systems in our environment and the evolution of the internet as a service oriented network connote two things: the demand for ubiquitous computing, and, the abstraction of users as consumers and applications as services, as in Service Oriented Computing (SOC) and Web Service domains.

This Thesis studies Class 2 Opportunistic Networks, Oppnets--in short. Oppnets propagate dynamic interconnection of heterogeneous devices/networks/systems and the integration of their resources or services-such as computation, communication, sensing, actuation, and storage -irrespective of the discrepancies in hardware, software, protocols, or standards employed, to enable ubiquitous computing. The novelty of Oppnets …

Abstraction, Extension And Structural Auditing With The Umls Semantic Network, Yan Chen

Dissertations

The Unified Medical Language System (UMLS) is a two-level biomedical terminological knowledge base, consisting of the Metathesaurus (META) and the Semantic Network (SN), which is an upper-level ontology of broad categories called semantic types (STs). The two levels are related via assignments of one or more STs to each concept of the META.

Although the SN provides a high-level abstraction for the META, it is not compact enough. Various metaschemas, which are compact higher-level abstraction networks of the SN, have been derived. A methodology is presented to evaluate and compare two given metaschemas, based on their structural properties. A consolidation …

Ontology Learning For The Semantic Deep Web, Yoo Jung An

Dissertations

Ontologies could play an important role in assisting users in their search for Web pages. This dissertation considers the problem of constructing natural ontologies that support users in their Web search efforts and increase the number of relevant Web pages that are returned. To achieve this goal, this thesis suggests combining the Deep Web information, which consists of dynamically generated Web pages and cannot be indexed by the existing automated Web crawlers, with ontologies, resulting in the Semantic Deep Web. The Deep Web information is exploited in three different ways: extracting attributes from the Deep Web data sources automatically, generating …

The Development And Evaluation Of Software To Foster Professional Development In Educational Assessment, Morgan C. Benton

Dissertations

This dissertation sought to answer the question: Is it possible to build a software tool that will allow teachers to write better multiple-choice questions? The thesis proceeded from the finding that the quality of teaching is very influential in the amount that students learn. A basic premise of this research, then, is that improving teachers will improve learning. With this foundation, the next question became what area of teaching to improve. The literature on educational assessment indicated that teachers lack competence at effective assessment, particularly in the area of multiple-choice question generation. It is likely that improvement in this area …

Taux : A System For Evaluating Sound Feedback In Navigational Tasks, Robert J. Lutz

Dissertations

This thesis presents the design and development of an evaluation system for generating audio displays that provide feedback to persons performing navigation tasks. It first develops the need for such a system by describing existing wayfinding solutions, investigating new electronic location-based methods that have the potential of changing these solutions and examining research conducted on relevant audio information representation techniques. An evaluation system that supports the manipulation of two basic classes of audio display is then described. Based on prior work on wayfinding with audio display, research questions are developed that investigate the viability of different audio displays. These are …

Some Combinational Optimization Problems On Radio Network Communication And Machine Scheduling, Xin Wang

Dissertations

The combinatorial optimization problems coming from two areas are studied in this dissertation: network communication and machine scheduling.

In the network communication area, the complexity of distributed broadcasting and distributed gossiping is studied in the setting of random networks. Two different models are considered: one is random geometric networks, the main model used to study properties of sensor and ad-hoc networks, where ri points are randomly placed in a unit square and two points are connected by an edge if they are at most a certain fixed distance r from each other. The other model is the so-called line-of-sight networks, …

User Evaluation Of The Performance Of Information Systems, Edward Mahinda

Dissertations

Information technologies (IT) are considered the primary survival factor for many organizations and the most critical success factor in businesses today. To justify the necessary investment in IT, user evaluation of information systems' performance in organizations is a key consideration. This research investigated a comprehensive and convenient means for end users to assess this performance.

Among the existing theories and models on the evaluation of information system performance based on intrinsic technological properties, the Web of System Performance (WOSP) model provides the most comprehensive basis for information system evaluation, and therefore merited further investigation. The research question was how well …

Complex Adaptive Systems Based Data Integration : Theory And Applications, Eliahu Rohn

Dissertations

Data Definition Languages (DDLs) have been created and used to represent data in programming languages and in database dictionaries. This representation includes descriptions in the form of data fields and relations in the form of a hierarchy, with the common exception of relational databases where relations are flat. Network computing created an environment that enables relatively easy and inexpensive exchange of data. What followed was the creation of new DDLs claiming better support for automatic data integration. It is uncertain from the literature if any real progress has been made toward achieving an ideal state or limit condition of automatic …

Leader Delegation And Trust In Global Software Teams, Suling Zhang

Dissertations

Virtual teams are an important work structure in global software development. The distributed team structure enables access to a diverse set of expertise which is often not available in one location, to a cheaper labor force, and to a potentially accelerated development process that uses a twenty-four hour work structure.

Many software teams are partially distributed, that is, part of the team is colocated. Such partially distributed global software teams are an important work structure in software development projects. However, little is known about what affects or improves team members’ motivation and job satisfaction in the partially distributed environment. This …

Automatic Prediction Of Solar Flares And Super Geomagnetic Storms, Hui Song

Dissertations

Space weather is the response of our space environment to the constantly changing Sun. As the new technology advances, mankind has become more and more dependent on space system, satellite-based services. A geomagnetic storm, a disturbance in Earth's magnetosphere, may produce many harmful effects on Earth. Solar flares and Coronal Mass Ejections (CMEs) are believed to be the major causes of geomagnetic storms. Thus, establishing a real time forecasting method for them is very important in space weather study.

The topics covered in this dissertation are: the relationship between magnetic gradient and magnetic shear of solar active regions; the relationship …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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, …