Physical Sciences and Mathematics Commons^™

Virtual Smarts - Optimizing The Coalescing Of People For Collective Action Within Urban Communities, Stephen Thomas Ricken

Dissertations

Despite the importance of individuals coming together for social group-activities (e.g., pick-up volleyball), the process by which such groups coalesce is poorly understood, and as a consequence is poorly supported by technology. This is despite the emergence of Event-Based Social Network (EBSN) technologies that are specifically designed to assist group coalescing for social activities. Existing theories focus on group development in terms of norms and types, rather than the processes involved in initial group coalescence. This dissertation addresses this gap in the literature through four studies focusing on understanding the coalescing process for interest-based group activities within urban environments and …

Fluorescent Probes And Functionalized Nanoparticles For Bioimaging: Synthesis, Photophysical Properties And Applications, Xinglei Liu

Dissertations

The development of new organic molecular probes with excellent photophysical properties and high fluorescence quantum yields is of considerable interest to many research areas including one- and two-photon fluorescence microscopy, fluorescence-based sensing methodologies, and cancer therapy. Series of organic linear-/non-linear optical molecules including squaraine derivatives, and fluorene derivatives as well as other bioconjugates are designed and synthesized during the doctoral study for the aim of ion detection (Chapter 5), photo dynamic therapy, and deep-tissue imaging (Chapter 4). These optical probes are capable of absorbing light in the near infrared (NIR) window and thus have deeper penetration and cause less photodamage …

Kinetic Study Of Free Radical-Radical Reactions Of Combustion Importance At Elevated Pressures, Chao Yan

Dissertations

Combustion mechanisms consist of hundreds elementary reactions of free radicals and stable molecules. Radical-radical elementary reactions play important roles due to the high concentration in which free radicals are accumulated in combustion systems. Radical-radical reactions are typically multi-channel. Some of the channels might be of chain propagation or even chain branching nature, while other channels might be of chain termination nature. The relative importance of different channels is pressure dependent. Compared to radical-molecule reactions, radical-radical reactions are much less studied. This is due to the difficulties of well characterized quantitative production of radical species as well as due to the …

Structural Studies To Determine The Mechanisms Supporting Multiferroic And Ferroelectric Properties Of Complex Oxides, Han Zhang

Dissertations

Multiferroics are a class of materials which possess both magnetic and electrical polarization with possible coupling between them. They show promise to enable new sensors and data storage devices with novel features, such as the possibility of writing polarization bits with magnetic fields at low power. The coexisting magnetic and ferroelectric order parameters are usually weakly coupled, preventing practical use. The development and study of new classes of materials with large magnetoelectric couplings is of high importance. Understanding the structure of these materials is key to this effort.

As one class of these systems, the RX3(BO₃)₄ has …

High Performance Cloud Computing On Multicore Computers, Jianchen Shan

Dissertations

The cloud has become a major computing platform, with virtualization being a key to allow applications to run and share the resources in the cloud. A wide spectrum of applications need to process large amounts of data at high speeds in the cloud, e.g., analyzing customer data to find out purchase behavior, processing location data to determine geographical trends, or mining social media data to assess brand sentiment. To achieve high performance, these applications create and use multiple threads running on multicore processors. However, existing virtualization technology cannot support the efficient execution of such applications on virtual machines, making them …

Experiments And Multi-Field Modeling Of Inelastic Soft Materials, Shuolun Wang

Dissertations

Soft dielectrics are electrically-insulating elastomeric materials, which are capable of large deformation and electrical polarization, and are used as smart transducers for converting between mechanical and electrical energy. While much theoretical and computational modeling effort has gone into describing the ideal, time-independent behavior of these materials, viscoelasticity is a crucial component of the observed mechanical response and hence has a significant effect on electromechanical actuation. This thesis reports on a constitutive theory and numerical modeling capability for dielectric viscoelastomers, able to describe electromechanical coupling, large- deformations, large-stretch chain-locking, and a time-dependent mechanical response. This approach is calibrated to the widely-used …

Rapid Generation Of Jacobi Matrices For Measures Modified By Rational Factors, Amber Sumner

Dissertations

Orthogonal polynomials are important throughout the fields of numerical analysis and numerical linear algebra. The Jacobi matrix J for a family of n orthogonal polynomials is an n x n tridiagonal symmetric matrix constructed from the recursion coefficients for the three-term recurrence satisfied by the family. Every family of polynomials orthogonal with respect to a measure on a real interval [a,b] satisfies such a recurrence. Given a measure that is modified by multiplying by a rational weight function r(t), an important problem is to compute the modified Jacobi matrix Jmod corresponding to the new measure from knowledge of J. There …

Functional Emulsions Via Thiol-Ene Chemistry, Douglas Amato

Dissertations

Polymer particles (micro to nano) with tunable functionality have emerged as a promising and viable technology platform for applications including coatings, cosmetics, nanomedicine, and imaging. Unfortunately, the lengthy polymerization time and lack of intrinsic functionality in the monomers used to fabricate particles is an industrial challenge. Thiol-ene chemistry cirmcumvents these limitations with very rapid polymerization kinetics, high reaction yields, with supressed side reactions and inherent functionality. This dissertation demonstrates the utility of thiol-ene/yne polymerization in miniemulsion and microfluidics to generate functional materials in a one-pot-method. The functionality is typically generated via off-stoichiometry thiol-ene (OSTE) resins which allow for either excess …

Polymer Nanocomposites Containing High Aspect Ratio Particulates: Innovation In Co-Extruded Multilayer Barrier Films, Kevin Meyers

Dissertations

Delaminated montmorillonite (MMT) clay/ maleic anhydride grafted LLDPE nanocomposite multilayer films with alternating layers of LDPE were produced through multilayer co-extrusion. The MMT concentration within the nanocomposite layers was increased through annealing the films in the melt due to a mismatch in interdiffusion rates of the polymer layers. Analysis of the nanocomposite layers upon annealing revealed that the platelets impinged upon one another resulting in significant improvement in oxygen barrier in the multilayer system, exceeding the results of bulk nanocomposites.

Model analysis demonstrated that increasing the nanoplatelet aspect ratio or initial concentration in the filled layers would lead to even …

Photoelectrochemical Studies On Non-Noble Metal Based Catalysts Towards Tandem Solar Water Splitting, Arun Siddarth Sridhar

Dissertations

Photoelectrochemical (PEC) water splitting makes direct use of solar energy incident on semiconductor photoelectrodes, and it is a convenient, economic option to produce high purity hydrogen at low temperatures. The use of multiple light absorbers can increase overall solar energy utilization and provide a solution to the trade-off between overall band gap and band edge positioning of photoelectrodes specific to solar water oxidation and water reduction. The study of non-noble metal based catalysts for hydrogen evolution reaction (HER) and oxygen evolution reactions (OER) are essential for economic practical commercialization of photo-electrolyzers. This dissertation focuses on the use of a variety …

Cationic Ruthenium Complexes In Catalysis: The Activation Of Propargylic Alcohols Through Electronically Tuned Complexes, Matthew James Stark

Dissertations

With increasing complexity of metal complexes, it is of worthwhile interest to pursue systematic examinations of ligand modifications to study their impact on the reactivity of a catalyst. To that end, this study aimed to understand the effect electron-withdrawing ligands conveyed to catalytic activity in the etherification of propargylic alcohols and related reactions. A number of half-sandwich ruthenium complexes bearing ligands with varying electron–withdrawing properties were synthesized and structurally characterized. Their electronic and structural properties were investigated utilizing X-ray crystallography, revealing that the series of complexes did not vary significantly in structure. The complexes were studied electronically with cyclic voltammetry, …

Development Of Rules Of Attraction For Intercalated Guest Molecules Inside Of A Hydrogen Bonded Framework, Matthew Fischer

Dissertations

Supramolecular chemistry has synthesized large and small molecules which host guest molecules for several decades. What started as a way to mimic of enzymes in nature, has exploded into a sea of materials such as porous coordination polymers, low-density metal-organic frameworks, inclusion compounds, and hydrogen bonded frameworks. We previously designed a layered framework consisting of a metal complex with coordinate covalent ligands. These ligands have peripheral carboxylic acid groups which hydrogen bond to organic pillars containing terminal amines. The layered structure is separated by these pillars, which are closed-packed, creating 1-dimensional channels able to co-crystallize molecules. There is interest in …

Steric Effects On The Formation Of Manganese Oxide Clusters And 2-Dimensional Ammonium Formate Architectures, Carl Oberle

Dissertations

It has been demonstrated by the Beatty group that altering the identity of the ortho-substituent of a dianiline counterion affects the assembly and dimensionality of a cadmium-chloride layer from 2-D to 0-D. This work seeks to extend this finding to metal oxide and organic hydrogen-bonded materials. By systematically increasing the ortho­-substituent’s size on the benzoate building block of reported manganese oxide clusters, of formula Mn_xO_y(O₂C-R)_zL_w (where R = Alkyl, L = neutral monodentate ligand), we aim to impact the self-assembly of these materials relative to their parent …

Chemical Synthesis Of Staphylococcal Oligosaccharides, Satsawat Visansirikul

Dissertations

The Gram positive, cluster forming bacteria Staphylococcus aureus belongs to the family of opportunistic pathogens that may cause blood stream infections when the integrity of skin is broken and the immune system can no longer fight the infection. S. aureus has become one of the most frequent causes of infections in newborns, surgical patients, trauma and burn patients, patients receiving an implant, and dialysis patients with high mortality rates. As a matter of fact, S. aureus has become one of the largest public health and economic impacts amongst all bacterial infectious diseases worldwide. This situation is further complicated by the …

Highly Symmetric Multiple Bi-Frames For Curve And Surface Multiresolution Processing, Khulud Ziadi

Dissertations

Wavelets and wavelet frames are important and useful mathematical tools in numerous applications, such as signal and image processing, and numerical analysis. Recently, the theory of wavelet frames plays an essential role in signal processing, image processing, sampling theory, and harmonic analysis. However, multiwavelets and multiple frames are more flexible and have more freedom in their construction which can provide more desired properties than the scalar case, such as short compact support, orthogonality, high approximation order, and symmetry. These properties are useful in several applications, such as curve and surface noise-removing as studied in this dissertation. Thus, the study of …

Evolving Specialization In An Agent-Based Model Without Task-Switching Costs, Shane Meyer

Dissertations

This work examines the possibility of evolving the phenotypic specialization associated with division of labor in an agent-based model without task-switching costs. The model examines two groups competing for vital resources, where members of one group are capable of sharing resources with other agents in their group. Agents attempt to collect resources which allow them to reproduce, with more resources leading to a greater number of offspring by asexual reproduction. Four variants of the model are examined, with combinations of one or two resources and the presence of a foraging risk. The presence of the foraging risk can lead to …

Supporting User Evaluation Of Messaging Interactions With Potential Romantic Partners Discovered Online, Douglas Zytko

Dissertations

Online dating systems have transformed the way people pursue romance. To arrive at a decision to meet for a face-to-face date, users gather information about each other online pertinent to romantic attraction. Yet sometimes they discover on the date that they made the wrong choice. One aspect of online dating system-use that may be a contributing factor, but is largely overlooked in the literature, is interaction through text-based messaging interfaces. This dissertation explores how messaging interactions inform face-to-face meeting decisions through two qualitative studies, and explores through a mixed methods field study how innovative messaging interfaces that embody theory from …

Statistical Properties Of Population Stability Index, Bilal Yurdakul

Dissertations

Population stability is an important concept in model management. It is crucial to monitor whether the current population has changed from the population used during development of a model. For example, has the distribution of credit scores changed, and is the existing credit score model still valid? Population change may occur for many reasons–change in the economic environment, strategic change in the business, policy changes within the company, or changes in regulatory environment.

The population stability index (PSI) is a statistic that measures how much a variable has shifted over time, and is used to monitor applicability of a statistical …

Edge Induced Weightings Of Uniform Hypergraphs And Related Problems, Laars C. Helenius

Dissertations

The starting point of the research is the so called 1-2-3 Conjecture formulated in 2004 by Karoński, Luczak, and Thomason. Roughly speaking it says that the edges of any graph can be weighted from {1, 2, 3} so that the induced vertex coloring (as the sum of weights adjacent to a given vertex) is proper. The conjecture has attracted a lot of interest from researchers over the last decade but is still unanswered. More recently, the conjecture has been studied for hypergraphs.

The main result of this dissertation shows in particular that an analogous conjecture holds for almost all uniform …

Support Assurance-Based Software Development For Mission Critical Domains Using The Model Driven Architecture, Chung-Ling Lin

Dissertations

In the past decades, software development for mission critical applications has drawn great attention not only in various mission critical communities but also software engineering communities. One of the important reasons is that the failure of these systems can lead to some serious consequences such as huge financial loss and even loss of life. Therefore, software certification has become an important activity for mission critical applications in that software assurance for such a system should be certified. With the increasing complexity of a software system in mission critical sectors, certifiers have found hard time to understand how a software system …

Mapping And Interpreting The Glacial Geology Of Pictured Rocks National Lakeshore, Michigan, Sarah M. Vandermeer

Dissertations

Pictured Rocks National Lakeshore is among the most popular parks in Michigan, yet prior to this study, it was the only National Park that lacked a detailed surficial geology map characterizing the distribution of sediments and landforms. Additionally, much of the landscape remained unexplored. These factors prevented thorough interpretations of landscape development and evolution. This research aims to map and further explore the relationship of glacial sediments and landforms throughout Pictured Rocks to refine and expand the current understanding of glacial events that shaped this landscape.

A new, detailed (1:24,000-scale) surficial geology map of the ten 7.5-minute quadrangles that contain …

Exploring The Use Of Hierarchal Statistical Analysis And Deep Neural Networks To Detect And Mitigate Covert Timing Channels, Omar Darwish

Dissertations

Covert timing channels provide a mechanism to transmit unauthorized information across different processes. It utilizes the inter-arrival times between the transmitted packets to hide the communicated data. It can be exploited in a variety of malevolent scenarios such as leaking military secrets, trade secrets, and other forms of Intellectual Property (IP). They can be also used as a vehicle to attack existing computing systems to disseminate software viruses or worms while bypassing firewalls, intrusion detection and protection systems, and application filters. Therefore, the detection and mitigation of covert channels is a key issue in modern Information Technology (IT) infrastructure. Many …

A Holistic Computational Approach To Boosting The Performance Of Protein Search Engines, Majdi Ahmad Mosa Maabreh

Dissertations

Despite availability of several proteins search engines, due to the increasing amounts of MS/MS data and database sizes, more efficient data analysis and reduction methods are important. Improving accuracy and performance of protein identification is a main goal in the community of proteomic research. In this research, a holistic solution for improvement in search performance is developed.

Most current search engines apply the SEQUEST style of searching protein databases to define MS/MS spectra. SEQUEST involves three main phases: (i) Indexing the protein databases, (ii) Matching and Ranking the MS/MS spectra and (iii) Filtering the matches and reporting the final proteins. …

Statistical Models For Correlated Data, Xiaomeng Niu

Dissertations

Correlated data arise frequently in many studies where multiple response variables or repeatedly measured responses within subjects are correlated. My dissertation topic lies broadly in developing various statistical methodologies for correlated types of data such as longitudinal data, clustered data, and multivariate data.

Multiple response variables might be relevant within subjects. A univariate procedure fitting each response separately does not take into account the correlation among responses. To improve estimation efficiency for the regression parameter, this study proposes two estimation procedures by accommodating correlations among the response variables. The proposed procedures do not require knowledge of the true correlation structure …

Denoising Large Neuroimage Mri Data Using Spatial Random Effect Models, Leonard Chukuma Johnson

Dissertations

Spatial smoothing in Magnetic Resonance image (MRI) involves applying a filter to remove high frequency information and consequently improves signal-to-noise ratio that can greatly aid neurosurgeons in pre-surgical planning stages of tumor resection. This immensely reduces the time spent on Electrical stimulation mapping (ESM) prior to surgery. MRI's three-dimensional data provides voxel intensities with complex spatial relationship. The standard de facto spatial smoothing method, Gaussian Kernel smoothing, is satisfactory since a uniform smoothing is done for the whole brain. Secondly, the kernel smoothing technique assumes normality for the voxel intensity, but there is ample evidence in current research that indicates …

Elucidation Of The Toxicity Of Anthropogenic Nanoparticles In Environments Containing Heavy Metals, Chartanay Bonner

Dissertations

The design, synthesis, and applications of anthropogenic nanoparticles continue to rise as technologies utilizing the unique chemical and physical properties of materials with nanoscale dimensions emerge. Engineered silver nanoparticles (Ag NPs) possess antimicrobial properties toward several strains of antibiotic-resistant bacteria. The manufacturing and use of Ag NPs have led to their increased presence in the environment as pollutants. The interaction of Ag NPs with other pollutants influence their surface properties, aggregation state, stability and consequently, their toxic response toward microbial pathogens. In the present study, we examined the interaction of heavy metal ions (Cd²⁺, Hg²⁺, and …

Using Agent-Based Implementation Of Active Data Bundles For Protecting Privacy In Healthcare Information Systems, Raed M. Salih

Dissertations

Sharing healthcare information—including electronic health/medical records (EHRs/EMRs)—among healthcare information systems is necessary for improving the quality of healthcare. However, facilitating data exchange increases privacy threats—due to easier copying and dissemination of healthcare information.

We propose a solution that provides privacy protection for patients’ EHRs/EMRs disseminated among different authorized healthcare information systems. Our solution builds upon the existing construct named an Active Data Bundle (ADB). In the proposed solution, ADBs keep EHRs/EMRs as sensitive data; include metadata describing sensitive data and prescribing their use; and encompass a policy enforcement engine (called a virtual machine or VM), which …

Geochemical And Radiological Baseline Studies And Environmental Impact Of The Area Surrounding Barakah Nuclear Power Plant, Uae, Mouza Rashed Mohamed Al Rashdi

Dissertations

Geochemical, mineralogical and natural radiation analysis techniques were used for establishment of geochemical and radiological baseline around Barakah Nuclear Power Plant, UAE. The natural radioactivity concentrations of ²³⁸U (²²⁶Ra), ²³²Th and ⁴⁰K were measured for soil, shore and bottom sediment samples, using gamma spectrometry equipped with HPGe detector. In addition, alpha spectrometry was used to measure ²³⁴U/²³⁸U ratio for some selected samples. Furthermore, inductively coupled plasma atomic emission spectroscopy was used to measure the concentrations of heavy metals and Rare Earth Elements (REE). The grain size of the samples ranged from fine …

Functionalized Nanoporous Carbon Scaffolds For Hydrogen Storage Applications, Christopher Carr

Dissertations

Recent efforts have demonstrated confinement in porous scaffolds at the nanoscale can alter the hydrogen sorption properties of metal hydrides, though not to an extent feasible for use in onboard hydrogen storage applications, proposing the need for a method allowing further modifications. The work presented here explores how the functionalization of nanoporous carbon scaffold surfaces with heteroatoms can modify the hydrogen sorption properties of confined metal hydrides in relation to non-functionalized scaffolds (FS). Investigations of nanoconfined LiBH₄and NaAlH₄indicate functionalizing the carbon scaffold surface with nitrogen can shift the activation energy of hydrogen desorption in excess of …

Visualization Of Co-Authorshipin Dit Arrow, Dan Xu

Dissertations

With the popularization of information technology and the unprecedented development of online reading, the management and service of the library are facing severe challenges; the traditional library operation mode has been challenging to optimize the service. At the same time, there is also a fatal impact on library collection and systematic management, however, with the development of visualization techniques in management and service, the library can alleviate the effect of the current network information basically, which achieves the intellectual development of library field. This study empirically provides the evidence to indicate that the force directed layout has the statistically significant …