Digital Commons Network^™

Distributed Local Trust Propagation Model And Its Cloud-Based Implementation, Dharan Kumar Reddy Althuru

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World Wide Web has grown rapidly in the last two decades with user generated content and interactions. Trust plays an important role in providing personalized content recommendations and in improving our confidence in various online interactions. We review trust propagation models in the context of social networks, semantic web, and recommender systems. With an objective to make trust propagation models more flexible, we propose several extensions to the trust propagation models that can be implemented as configurable parameters in the system. We implement Local Partial Order Trust (LPOT) model that considers trust as well as distrust ratings and perform evaluation …

Impact Of Sar Image Formation Quality On Target Separability, Cody A. Lawyer

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The polar format algorithm (PFA) allows the use of computationally efficient fast Fourier transforms in synthetic aperture radar (SAR) image formation, but introduces phase errors when making the far-field approximations that facilitate this approach. The phase errors cause spatially variant distortion and defocus in the formed image. These effects may complicate target recognition applications. To limit the impact of defocus, scene size is usually limited such that the maximum quadratic phase error within an image falls below some threshold. This thesis looks at how distortion and defocus affects the classification of targets, with the hope of developing an application-driven scene …

Alternative Indices Of Performance: An Exploration Of Eye Gaze Metrics In A Visual Puzzle Task, Sheldon M. Russell

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Of interest to the U.S. Air Force is the ability to develop and characterize the level of workload that operators are under at any given point. When an operator's cognitive resources exceed demands, a 'red line' of performance may be crossed after which performance breaks down. What is needed is an estimate of operator state; a 'dipstick' for the operator in order to assess the level of 'resources' available, in order to avoid performance problems. Traditional approaches use secondary tasks (e.g., mental arithmetic) or secondary physiological measures (e.g., heart rate variability) for state assessment. However, the current work was motivated …

Analysis Of A Fuel Cell Combustor In A Solid Oxide Fuel Cell Hybrid Gas Turbine Power System For Aerospace Application, Ryan R. Sinnamon

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Over the last few years, fuel cell technology has significantly advanced and has become a mode of clean power generation for many engineering applications. Currently the dominant application for fuel cell technology is with stationary power generation. Very little has been published for applications on mobile platforms, such as unmanned aerial vehicles. With unmanned aerial vehicles being used more frequently for national defense and reconnaissance, there is a need for a more efficiency, longer endurance power system that can support the increased electrical loads onboard. It has already been proven by others that fuel cell gas turbine hybrid systems can …

A Chemical Free Approach For Increasing The Biochemical Surface-Enhanced Raman Spectroscopy (Sers)-Based Sensing Capabilities Of Colloidal Silver Nanoparticles, Kevin Michael Dorney

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The unique optoelectronic properties of silver nanoparticles (AgNPs) have led to their explosive use in a multitude of both research and industrial settings in recent years. Localized surface plasmon resonance (LSPR) exhibited by AgNPs has been exploited extensively as a nano-scale probe in a variety of spectroscopic detection modalities, particularly in surface-enhanced Raman spectroscopy (SERS). The SERS effect is highly dependent upon the LSPR interaction with optical laser frequencies, thus optimization of LSPR via specific control of AgNP dimensionality and composition of the surrounding medium is vital for increasing the efficacy of SERS-based nano-sensing. This work aimed to augment LSPR …

Thermal Properties Of Magnetic Nanoparticles In External Ac Magnetic Field, Anna Beata Lukawska

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This work studies thermal properties of magnetic nanoparticles in an external ac magnetic field. Dried iron and cobalt nanoparticles were prepared by thermal decomposition of iron pentacarbonyl (Fe(CO)5) and dicobalt octacarbonyl (Co2(CO)8), triscobalt nona(carbonyl)chloride (Co3(CO)9Cl), or tetracaobalt dodecacarbonyl (Co4(CO)12) [1]. The samples had different mean diameters: 5.6 - 21.4 nm for iron and 6.5 - 19.4 nm for cobalt. Each sample was exposed to ac magnetic field and the increase in temperature of the sample was measured. Results were analyzed to find the critical diameters for the transitions from multi-domain to single-domain and from single-domain to superparamagnetic regime. The nanoparticles …

Influence Of Curved Geometries On The Fatigue Life Of Laser Peened Components, Anoop Vasu

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Generating compressive residual stresses at the critical stress locations can prevent or delay structural component failure. Laser peening is a well-known method for inducing compressive residual stresses. The plastic deformation created by the planar shock waves near the surface regions is the major cause for the generation of compressive residual stresses. Apart from the planar waves, release waves at the border of impact are generated that act against the plastic deformation created by planar waves. This decrease of plastic deformation reduces the compressive residual stress generated near the surface regions of peened components. Laser peening of curved geometries creates compressive …

Effect Of Land Use On Mercury In Soils Of Southwest Ohio, Rebecca L. Gamby

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Terrestrial biomass and soils are a primary reservoir of mercury (Hg) derived from natural and anthropogenic sources; however, the fate and stability of Hg in the surface soil reservoir and its susceptibility to change as a result of human activities is relatively unknown. In this study, soil concentrations of Hg and lead (Pb) were compared between old- and new-growth forest soils as well as fallow grassland and agricultural soils in southwest Ohio. Old- and new-growth forest soils had significantly greater concentrations of soil Hg, Pb, and organic matter than fallow and cultivated soils in the O/A horizon. Mercury:organic matter ratios …

The Synthesis Of 1,4-Bis(2-(4-(4-Fluorobenzoyl)Phenoxyethoxy)Benzene And Poly(Aralkyl Ether)S Derived From 1,4-Bis(2-Tosyloxyethoxy)Benzene, Juraj Drzic

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The reaction of 1,4-bis(2-tosyloxyethoxy)benzene or 1,4-bis(bromoethoxy)-benzene with 4-fluoro-4'-hydroxybenzophenone was carried out under a variety of conditions. Changes were made in solvent, reaction time, work-up and base. All attempts to generate a bis(fluorobenzophenone) monomer were unsuccessful. In some cases the presence of the half-product could be determined. In other cases, an elimination product was indicated. The ditosylate, 1,4-bis(2-tosyloxyethoxy)benzene was reacted with bisphenol-A, bisphenol-AF, bis(4-hydroxyphenyl)diphenylmethane and 9,9-bis(4-hydroxyphenyl)fluorene in a dioxane - water solution in the presence of sodium hydroxide to produce four polymers. The polymers were characterized by thermal analysis (TGA) to reveal 5% weight loss temperatures of 338°, 350°, 365° and …

Development And Application Of An Analyst Process Model For A Search Task Scenario, Hendrickson K. Karl

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A key intelligence analyst role in open source search is the transformation of data into understanding. Better comprehension is needed of how new tools impact the analyst search process. The use of function analysis, heuristic analysis, and a usability study combine to provide the basis for developing an analyst process model, which affords the researcher with a structure to measure the impact of tools and expertise in performing a search task. The experiment utilized representative analyst scenario tasks in comparing baseline tools with the Geospatial Open Search Toolkit (GOST). The results show error rates increase when using a new toolset …

Characterization Of A Utica Shale Reflector Package Using Well Log Data And Amplitude Variation With Offset Analysis, Andrei Butterfield

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Using well logs and AVO gradient analysis, I identify and characterize a package of reflectors associated with the Utica Shale from vibroseis data collected by Wright State University at the Gabor Gas Storage field near Canton, Ohio. I also correlate TOC measurements from wells to densities and velocities at the same depths. On the seismic data, I interpret prominent reflections from the top and bottom of the Utica Shale and an intra-Utica reflector of varying frequency content associated with a velocity/density low in well log data. I investigate the possibility that the lateral variation in frequency content and change in …

Modeling Physical And Hydraulic Properties Of Disordered Porous Media: Applications From Percolation Theory And Fractal Geometry, Behzad Ghanbarian-Alavijeh

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A fundamental component of the hydrologic cycle is the movement of fluids in the pore space of geological formations and soils. Prediction of the motion of fluids in such porous materials requires first modeling the physical properties of the medium itself, and second, invoking a capable theory to describe fluid transport in tortuous interconnected pathways. In this dissertation, for the former we use fractal geometry since most phenomena in nature are fractal, and for the latter percolation theory is applied because it has successfully described flow and transport in disordered networks and media. We propose models for the soil water …

Study On The Vortex Wake Of An Airfoil Equipped With Flexible Trailing Edge Fringes, Zhengkai He

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With the inspiration of owl's silent flight, a traditional airfoil S833 equipped with flexible fringes on the trailing edge is investigated through numerical simulation and experiments in a wind tunnel. The newly constructed airfoil is modeled and numerically investigated. An incompressible, 2D and viscous flow solver in the Computational Fluid Dynamics (CFD) software FLUENT is utilized to conduct the numerical simulation on the vortex flow feature in the wake of the airfoil. A User Defined Function code was applied to generate the defined motion of flexible fringes. The effects of the flapping frequency of the fringe and the deformation pattern …

Hierarchical Porous Structures Functionalized With Silver Nanoparticles: Adaptation For Antibacterial Applications, Anil Kumar Karumuri

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For a large number of applications involving surface interactions, there is an ever growing demand for materials with high specific surface area (surface area to volume ratio). Porous materials and nanomaterials offer higher specific surface area (SSA) each with their respective advantages and disadvantages. This research program is focused on bringing the two approaches together to create truly "hierarchical" materials that combine advantages of both while minimizing their disadvantages. In this study, various carbon based porous geometries were fabricated by grafting carbon nanotubes (CNT) onto highly porous reticulated carbon foams. These structures were further modified by functionalizing metal nanoparticles such …

Imperfect Situation Analysis: Representing The Role Of Error And Uncertainty In Modeling, Simulation And Analysis, Victor Eaton Middleton

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Much of traditional modeling, simulation and analysis (MS&A) is supported by engineering models - deterministic, Newtonian physics-based representations of closed systems. Such approaches are not well-suited to represent the intricacies of human behavior. This research advocates and seeks to articulate the concept of a more human- centric approach to MS& A, one that better represents decision-making and other cognitive aspects of human behavior as well as it does physical activity.

It starts with a view of individuals and groups as complex adaptive systems, which are best represented using agent-based modeling. Representation of human behavior through intelligent agents incorporates models of …

Development Of A Co-Culture System To Mimic The Transfection Of Hsv-1 From Keratinocytes To Neuronal Cells, David A. Dixon

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To more closely mimic the in vivo progression of HSV-1 a novel in vitro method was created. In this study HEL-30 keratinocytes were infected with a 0.1 MOI of HSV-1 and plated unto a membrane with 8μm diameter pores. The membrane insert was then placed into culture wells that contained Neuro-2a cells (N2A). The neurites from the neuronal cells made cell-to-cell contact with the infected HEL-30 cells and the virus was transmitted into the neuronal cells. To determine if infection occurred in the N2A cells the cells were lysed and the lysate incubated with Vero cells to titrate virus plaque …

Exploring How Middle School Students' Epistemologies In Practice Change Across Time With Varying Content Areas And Knowledge Product Contexts, Mackenzie Evan English

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Recently, the National Research Council developed A Framework for K-12 Science Education (NRC, 2012), to support a new vision of science education. The Framework (2012) focuses on three integrated dimensions--disciplinary core ideas, crosscutting concepts, and scientific and engineering practices which is different than traditional ways of learning science. I focused on students' engagement in scientific practices, attention to epistemological practices (EIP) that guide students' construction, evaluation and revision of knowledge products. I examined how students EIP's changed over time and across contexts with respect to different knowledge product types (models and explanations). I present data from 103, 6th grade students …

Testing Of Two Novel Semi-Implicit Particle-In-Cell Techniques, Trenton J. Godar

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PIC (Particle-in-cell) modeling is a computational technique which functions by advancing computer particles through a spatial grid consisting of cells, on which can be placed electric and magnetic fields. This method has proven useful for simulating a wide range of plasmas and excels at yielding accurate and detailed results such as particle number densities, particle energies, particle currents, and electric potentials. However, the detailed results of a PIC simulation come at a substantial cost of computational requirement and the algorithm can be susceptible to numerical instabilities. As processors become faster and contain more cores, the computational expense of PIC simulations …

The Synthesis Of Polyimides Containing Oxyalkylene Units, Kristy Wickman

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A series of oxyalkylene containing diamines, 1,4-bis(2-(4-aminophenoxy)-ethoxy)benzene, 2,2-bis[4-(2-(4-nitrophenoxy)ethoxy)phenyl]hexafluoropropane, 9,9-bis(4-(2-(4-nitrophenoxy)ethoxy)phenyl)fluorene, and bis(4-(2-(4-nitrophenoxy)ethoxy)-phenyl)diphenylmethane, has been synthesized from the reduction of 1,4-bis(2-(4-nitrophenoxy)ethoxy)benzene, 2,2-bis[4-(2-(4-nitrophenoxy)ethoxy)phenyl]-hexafluoropropane, 9,9-bis(4-(2-(4-nitrophenoxy)ethoxy)phenyl)fluorene, bis(4-(2-(4-nitrophenoxy)ethoxy)phenyl)diphenylmethane, respectively. The diamine compounds were reacted reacted with 6FDA to obtain the corresponding polyimide. The polymerization was done in a one-pot reaction with m-cresol and isoquinoline. The polyimides displayed glass transition temperatures ranging from 186-231°C and thermal stability <400°C.

Fatigue Based Structural Design Exploration Via Engineering Data Analytics, Hao Li

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In manufacturing industry, a successful machine development requires the durability of structure components to meet fatigue life targets. The typical way to obtain fatigue design loads for conceptual design exploration is based on hand calculations or historical data to capture envelopes of expected system responses, which may not guarantee to capture actual damaging loads. In this study, a new approach is developed to extract a fatigue design load set directly from measured load data for a conceptual design exploration. The proposed framework integrates the techniques from data analytics and physics based engineering mechanics to amplify and detect fundamental damaging load …

Combating Integrity Attacks In Industrial Control Systems, Chad Arnold

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Industrial Control Systems are vulnerable to integrity attacks because of connectivity to the external Internet and trusted internal networking components that can become compromised. Integrity attacks can be modeled, analyzed, and sometimes remedied by exploiting properties of physical devices and reasoning about the trust worthiness of ICS communication components.

Industrial control systems (ICS) monitor and control the processes of public utility that society depends on - the electric power grid, oil and gas pipelines, transportation, and water facilities. Attacks that impact the operations of these critical assets could have devastating consequences. The complexity and desire to interconnect ICS components have …

Non-Equilibrium Models For High Temperature Gas Flows, Daniil Andrienko

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A multi-physical approach is developed for non-equilibrium high enthalpy flows to cover a wide range of interdisciplinary studies. Compressible Navier-Stokes equations are coupled with the chemical model and equation of energy conservation for internal degrees of freedom. The model is capable of accounting for the non-equilibrium dissociation and thermal radiation heat transfer in gas flows. The methodology covers a range of problems from the combustion in subsonic counter-flowing jets to the hypersonic re-entry flows. The present approach attempts to validate the finite rate chemistry mechanisms by modeling the diffusive non-premixed flame of hydrogen at a very low Mach number. The …

A Novel Synergistic Model Fusing Electroencephalography And Functional Magnetic Resonance Imaging For Modeling Brain Activities, Konstantinos Michalopoulos

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Study of the human brain is an important and very active area of research. Unraveling the way the human brain works would allow us to better understand, predict and prevent brain related diseases that affect a significant part of the population. Studying the brain response to certain input stimuli can help us determine the involved brain areas and understand the mechanisms that characterize behavioral and psychological traits.

In this research work two methods used for the monitoring of brain activities, Electroencephalography (EEG) and functional Magnetic Resonance (fMRI) have been studied for their fusion, in an attempt to bridge together the …

Stop Cheating!: An Evaluation Of A Scientific Integrity Writing Strategy In General Chemistry I, Michelle L. Edwards

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Cheating in America has become an epidemic, which has unfortunately spread to academia. Researchers have long been interested in the trends in cheating behavior and the factors that influence these trends among undergraduate college students. Though cheating can take on many forms, in science, there is a deep concern about scientific misconduct related to research. Because training for future scientists begins in undergraduate courses, this study investigated the use of scientific integrity writing strategy in General Chemistry I at Wright State University. The goal of the study was to determine if providing scientific integrity and ethics training, while teaching students …

Routes To N-Heterocycle Functionalized Poly(Arylene Ether Sulfone)S, Jesse L. Picker

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The synthesis of poly(arylene ether sulfone)s, with a pendant aryl iodide, was achieved via nucleophilic aromatic substitution (NAS) polycondensation of 3-iodo-3',5'-difluoro-diphenylsulfone. The polymer series was subjected to amino acid promoted, copper catalyzed coupling reactions with various N-heterocycles. The resulting polymers became crosslinked and insoluble in any organic solvents. The iodo monomer was then subjected to an amino acid promoted, copper catalyzed coupling reaction with carbazole. The successful synthesis of 3'-(9-carbazole) 3,5-difluorodiphenylsulfone is reported. A series of PAES containing a carbazole substituent were synthesized and characterized. The polymers were characterized by a combination of NMR spectroscopy, SEC, TGA, DSC, UV-Vis spectroscopy. …

Biogeochemistry Of Sulfur Isotopes In Crystal Lake, Clark County, West-Central Ohio, Amanda Lynn Meyer

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Crystal Lake showed distinct biogeochemical patterns, which were governed by thermal stratification, photosynthesis, and sulfur redox processes. Field parameter measurements and water and Planktothrix rubescens samples were collected in May, August, and October, 2013 at the deepest point in the lake, to better understand these processes. At the metalimnion-hypolimnion boundary, P. rubescens produced chlorophyll and turbidity maxima. Photosynthesis produced oxygen-rich and nutrient-poor surface waters. The decay of organic matter produced anoxic, nutrient-rich water in the hypolimnion. Sulfate concentrations were high in the epilimnion and metalimnion, with a maximum at the layer of P. rubescens, and decreased with depth in the …

Mercury Distributions And Cycling In The North Atlantic And Eastern Tropical Pacific Oceans, Katlin L. Bowman

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The distribution of mercury (Hg) in the ocean is complex as a result of in situ chemical transformations and inputs from natural and anthropogenic sources. Within the ocean, inorganic Hg is methylated to monomethylmercury (MMHg), which bioaccumulates and biomagnifies in marine food webs and poses a health risk to humans who eat fish. The biogeochemistry of Hg in the ocean has been studied for decades, however, recently improved sampling and analytical techniques have allowed for an enhanced understanding of global distributions of different Hg species. This dissertation uses a newly developed method for the analysis of MMHg that improves detection …

Biaxial Material Design Method For The Reduced Aperture Waveguide Model, Jason M. Brand

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The design and characterization of metamaterials has emerged as a field of great interest in electromagnetics in recent years. The characterization has been accomplished primarily by means of fabrication, measurement, and parameter estimation. Previous work by Knisely and Havrilla [8] has shown that biaxial anisotropy can be created by machining air vias uniaxially into a homogeneous, isotropic material. This research project proposes a design method for manufactured biaxial materials. Full wave modeling and simulation is used for samples with varying via size, separation and pose to obtain the scattering parameters S11 and S21. To compare the simulated S-parameters to theoretical …

Environmental Factors Affecting Methylmercury In Fish Of The Laurentian Great Lakes Region, Joel Harvey

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Monomethylmercury (MMHg) can accumulate in fish to concentrations that pose a threat to the health of fish, piscivorous organisms, and humans who eat fish. A variety of environmental factors have been hypothesized to influence either the methylation of inorganic Hg or the bioaccumulation and magnification of MMHg. This study investigates the influence of selected environmental factors on MMHg concentrations in freshwater fish across a regional scale, most of the U.S. portion of Laurentian Great Lakes region. Fish MMHg was correlated with proton deposition, sulfate deposition, nitrate deposition, mercury deposition, pH, watershed area, and Secchi depth. Only proton deposition was positively …

Surface Effects On Critical Dimensions Of Ferromagnetic Nanoparticles, Vartika Chaudhary

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This work studies surface effects on the critical dimensions of ferromagnetic nanoparticles. Iron nanoparticles with different mean diameters from 5.9 nm to 21.4 nm used in this research were prepared by thermal decomposition of iron pentacarbonyl in the presence of oleic acid/octyl ether at Cambridge University, United Kingdom. Heating response of these ferromagnetic nanoparticles suspended in water were measured experimentally during which same amount of iron nanoparticles and di-ionized water were irradiated by an alternating magnetic field and the increase in temperature of these samples was measured. Heating performance of nanoparticles was described in terms of Specific Absorption Rate (SAR) …