Digital Commons Network^™

Selective Free-Standing Through-Wafer Porous Silicon Membrane (Sftpsm) For Integrated Meta-Material Devices, Bella Liu Yao

Browse all Theses and Dissertations

Meta-materials have attracted considerable attention due to their unique electromagnetic properties, such as negative permittivity (ε), negative magnetic permeability (μ), and negative index of refraction. These devices have shown broad flexibility in compact phase shifter, backward leaky-wave antenna, and high-directivity coupled-line coupler applications; however, integrated devices utilizing meta-material structures have not yet surfaced due to a lack of integration technology.

In this work, a novel concept of integrated meta-materials is presented, using free-standing porous silicon (PS) membranes of periodic magnetic wire arrays (PMWA). The free-standing PS membranes were fabricated on p-type silicon substrates through electrochemical anodization. Systematic investigations have been …

The Effectiveness Of Pilot Response To Generate Concatenated Downlink Messages After Evaluation Of Hybrid Graphic-Text Clearances, Steven Brent Kiss

Browse all Theses and Dissertations

Data-Link Communication, or DataComm, is a digital text messaging system providing a means of communication between Air Traffic Control (ATC) and pilots. Current Pilot/ATC communication is via voice radio, but the number of ATC operators and voice channels are finite, which limits the number of aircraft voice transmission can accommodate. The number of aircraft within the National Airspace System (NAS) is expected to double between 2004 and 2025, and a transition from voice to DataComm is a necessity. DataComm is an integral part of the NAS and is implemented in incremental phases increasing its functions and capability. There are many …

Stability Of A Fuzzy Logic Based Piecewise Linear Hybrid System, Aaron W. Seyfried

Browse all Theses and Dissertations

Complex cyber-physical systems are difficult to model and control. However, humans are capable of accomplishing these tasks by constantly adapting and redefining the rules to control these complex systems. Fuzzy logic provides a means of encoding human inference into a control methodology. However, the fuzzy logic controllers are nonlinear and their stability is difficult to verify. Therefore, the widespread usefulness of fuzzy logic controllers is limited. It has been proven that fuzzy logic controllers can be implemented as piecewise linear switched controllers. It has also been shown that the piecewise linear system can be implemented as a hybrid system. Piecewise …

Effect Of Rat Strain Stereotactic Coordinates On Infarct Volume, Saagar K. Sanghvi

Browse all Theses and Dissertations

Ischemic stroke makes up 87% of all hospital-admitted stroke cases annually; the primary treatment for these cases is intravenous administration of tPA within a 3.5 hour window from stroke onset. A long-term delayed ischemic stroke treatment proposed by this study was a combination of the pharmaceuticals Fluoxetine (SSRI), Simvastatin (statin), and ascorbic acid (Vitamin C). 51 adult rat subjects (10-12 months of age; 44 Sprague Dawley, 7 Long Evans) were given a combination of the drugs for 31 days. Drugs were given through voluntary oral administration via sugar cookie-dough balls to reduce inhibition of neurogenesis through stress-related glucocorticoid production. Drug …

The Effects Of Multicollinearity In Multilevel Models, Patrick Carl Clark Jr.

Browse all Theses and Dissertations

This study examined a method for calculating the impact of multicollinearity on multilevel modeling. The major research questions concerned a) how the simulation design factors affect (multilevel variance inflation factor) MVIF, b) how MVIF affects standard errors of regression coefficients, and c) how MVIF affects significance of regression coefficients. Monte Carlo simulations were conducted to address these questions. Predictor relationships were manipulated in order to simulate multicollinearity. Findings indicate that a) increases in relationships among Level 1 predictors and also relationships among Level 2 predictors led to increased MVIF for those specific variables, b) as MVIF increases for a predictor, …

Amp-Activated Protein Kinase Knockdown In Labyrinthine Trophoblast Cells Results In Altered Morphology And Function, Erica Ashton Kayleigh Carey

Browse all Theses and Dissertations

The placenta is a transient organ that develops upon initiation of pregnancy and is essential for fetal development and survival. The rodent placenta consists of three layers with predominantly analogous cell types in the human placenta. The labyrinth layer, which lies closest to the fetus, facilitates nutrient and waste exchange between mother and baby. Abnormalities of the placenta may occur as a result of cellular stress and have been associated with the pregnancy-associated disorders, intrauterine growth restriction and placental insufficiency. AMP-activated protein kinase (AMPK) is a master sensor of cellular stress and changes in AMPK expression or activation could be …

Resource Control And Political Development In Africa: The Cases Of The Democratic Republic Of The Congo And The Republic Of Botswana, Oweka Ime

Browse all Theses and Dissertations

Ironically, it appears that the countries with the greatest resource wealth have often had the hardest time achieving political and economic stability. Is there a direct correlation between the way in which natural resources are controlled within a country and its democratic process? How do other factors come into play, such as MNC involvement or the level of natural resource revenue dependency? This study compares and contrasts two resource-rich countries: the Democratic Republic of the Congo and the Republic of Botswana between 1885 and 2012. To address the problem under investigation, three hypotheses have been formulated: 1) the higher the …

Utility Of A Volume-Regulated Drive System For Direct Mechanical Ventricular Actuation, Benjamin A. Schmitt

Browse all Theses and Dissertations

Direct Mechanical Ventricular Actuation (DMVA) is a non-blood contacting cardiac assist device that augments ventricular function. The purpose of this study was to determine if a volume-regulated "hand pump" drive system and a pressure-regulated "switch tank" drive system provide equivalent levels of cardiac support. Canine (n=2) and swine (n=4) were instrumented for hemodynamic monitoring and intravascular echocardiography. DMVA support was assessed during both severe heart failure and fibrillation. Pump function was evaluated using hemodynamic measures to calculate stroke work. Myocardial function was assessed using echocardiographic speckle tracking to quantify strain rate. Results were compared between groups using paired t-tests. There …

An Investigation Of Thermal Imaging To Detect Physiological Indicators Of Stress In Humans, Carl Brady Cross

Browse all Theses and Dissertations

Real-time, stand-off sensing of humans to detect emotional state would be valuable in many defense, security and medical scenarios. Using a multimodal sensor platform that incorporates high-resolution visible-wavelength and mid-wave infrared cameras and a millimeter-wave (mmW) radar system, the detection of physiological indicators of psychological stress is tested through laboratory experiments. Our approach focuses on thermal imaging to measure temperature patterns in distinct facial regions representative of underlying hemodynamic patterns. Experiments were designed to: 1) determine the ability of thermal imaging to detect high levels of psychological stress and assess responses to physical versus psychological stressors; 2) evaluate the fidelity …

A Semantics-Based Approach To Machine Perception, Cory Andrew Henson

Browse all Theses and Dissertations

Machine perception can be formalized using semantic web technologies in order to derive abstractions from sensor data using background knowledge on the Web, and efficiently executed on resource-constrained devices. Advances in sensing technology hold the promise to revolutionize our ability to observe and understand the world around us. Yet the gap between observation and understanding is vast. As sensors are becoming more advanced and cost-effective, the result is an avalanche of data of high volume, velocity, and of varied type, leading to the problem of too much data and not enough knowledge (i.e., insights leading to actions). Current estimates predict …

Fabrication And Mass Transport Analysis Of Tape Cast Nano-Silver High Temperature Solder, Jared Ray Mccoppin

Browse all Theses and Dissertations

The principal objective in this research was to develop a die attach method to facilitate the use of wide band gap semiconductors in high-temperature environments, and study fundamental mass transport in nano-initiated die attach microstructure at high temperature. Low temperature sintering silver-nano-pastes have been demonstrated as an effective method for die attach by other groups. Fabrication and optimization of the die attach method in this work was accomplished via tape casting. A novel binder system and a bimodal particle distribution were utilized. The tape casting method allowed die attach materials to be pre-stressed. Fundamental understanding of creep deformation process and …

Electromagnetic Characterization Of Af455 With Dna-Ctma In Solvent Blends, Jessica Marie Hendricks

Browse all Theses and Dissertations

This work studies the electromagnetic properties of AF455, a two photon dye, DNA bound with cetyltrimethyl ammonium (CTMA), in liquid solvent blends for use in thin film optical filters. The liquid properties of the materials are believed to be transferred to the films. The solvent blends used are ratios of toluene (T) and dimethyl sulfoxide (DMSO). The complex permittivity and permeability of the samples are measured using the short open coaxial line technique in the frequency range of 1.0 x 107 Hz to 2.0 x 109 Hz. In this frequency range, AF455 does not act as a two photon absorber. …

Synthesis And Electrodeposition Of Mixed Metal Trinuclear Clusters Of Molybdenum And Chromium In Ionic Liquid Onto A Platinum Electrode, Lynn Renee Frock

Browse all Theses and Dissertations

Electrochemical properties of [Mo3O2(O2CCH3)6(H2O)(CF3SO2H)2 and [Cr2Mo(u2-CH3COO)6(u3-O)(H2O)3][CF3SO3] in 1-ethyl-3-methylimidazolium bis(pentafluoroethanesulfonyl)-imide ionic liquid was investigated. Cyclic voltammograms using a Platinum electrode indicated deposition had occurred for the [Mo3O2(O2CCH3)6(H2O)(CF3SO2H)2 metal cluster but had not for the polynuclear complex [Cr2Mo(u2-CH3COO)6(u3-O)(H2O)3][CF3SO3]. Constant potential electrolysis of -1.23 V using a platinum foil electrode was performed. Scanning electron microscopy in combination with energy dispersion spectroscopy confirmed that deposition had occurred.

Dangerous Feminine Sexuality: Biblical Metaphors And Sexual Violence Against Women, Lisa M. Ewing

Browse all Theses and Dissertations

This analysis responds to an ongoing debate between feminist and traditional readings of sexually violent (SV) metaphors in the prophetic texts of Hosea, Jeremiah, and Ezekiel, and the New Testament book of Revelation. Whereas feminist scholars have often argued that such metaphors are built upon the exploitation of women's sexuality, traditionalist scholars have insisted that the metaphors are merely literary devices that should only be read within their historical and literary contexts. Taking a moderate position, this analysis uses the cognitive metaphor theory to explain that the SV metaphors depend on cognitive associations of dangerous feminine sexuality to relate to …

Effect Of A Graded Layer On The Plastic Dissipation During Mixed-Mode Fatigue Crack Growth On Ductile Bimaterial Interfaces, Craig M. Baudendistel

Browse all Theses and Dissertations

An energy-based theory for predicting mode I fatigue crack growth rates in ductile metals based on the total plastic dissipation ahead of a crack tip was proposed in 2003. Since then, this theory has been extended to layered material systems that typically include mixed-mode loading and elastic/plastic mismatch. Previous research by the author first extended this theory to include a graded layer (i.e., no step change in material properties across the crack plane) with which to more accurately model a crack interface between two materials with a mismatch in plastic properties only. In the current research, the graded layer model …

Design And Implementation Of A 16-Bit Flexible Rom-Less Direct Digital Synthesizer In Fpga And Cmos 90nm Technology, Sunny Raj Dommaraju

Browse all Theses and Dissertations

A ROM-less direct digital synthesizer architecture is presented in this thesis. This architecture eliminates the ROM-based phase to sine wave amplitude converter, which is a bottleneck for pushing clock frequencies into the gigahertz range. The design consists of a 16-bit phase accumulator, a set of 18 band pass finite impulse response filters, a 12-bit digital to analog converter and a low pass filter to produce a sine wave with output frequencies ranging from 36 MHz to 72 MHz with a resolution of 3.05 kHz and a 55 dB spur free dynamic range. The same hardware can be used to achieve …

Spatialized Audio And Landmarks In Team Navigation, Andrew Hampton

Browse all Theses and Dissertations

Using data collected from a prior study that established the benefit of spatialized audio on team navigation, the current paper examines the underlying mechanisms by which that benefit arose. With linguistic measures extracted from trial transcripts, I study emergent patterns of conversation for four dyads as they attempt to rendezvous in an immersive virtual environment. Spatialized audio is compared to landmarks, traditionally viewed as integral to navigation tasks, on the basis of coordination and strategy. Analyses reveal that spatialized audio creates a decreased need to speak overall. Paired with the performance advantage, this creates a more linguistically efficient task structure. …

Mining Diversified Decision Trees Across Multiple Datasets To Capture Similarities And Alignable Differences, Qian Han

Browse all Theses and Dissertations

This dissertation studies the problem of mining shared and alignable difference knowledge structures across multiple datasets/applications. Shared and alignable difference knowledge structures are important for identifying analogies between application domains and for forming new hypothesis in challenging research applications, and for assessing the degree and types of knowledge-level similarities and differences between application domains for use in learning transfer. Generally speaking, shared knowledge structures characterize underlying datasets and highlight conceptual-level structural similarities among the datasets. This dissertation studies the mining of shared decision trees, which are a special type of shared knowledge structures. We first consider building one shared decision …

Novel Approaches For The Eradication Of Hiv Latently Infected Cells, Sally Al Ali

Browse all Theses and Dissertations

The development of a suitable experimental cell model to study HIV latency in primary cells could have a massive effect on the current approaches to eradicate virus in latently infected cells. The main proposal of this paper is to develop an in vitro HIV cell model that represents HIV latency in vivo, then to create a more effective viral vector in order to target HIV reservoirs. For this goal, a directed evolution method is suggested to be used in order to mutate the AAV cap gene to generate a recombinant AAV vector that is capable of infecting primary resting CD4+ …

Examination Of The African-American Father-Daughter Relationship: Application Of The Marschack Interaction Method, Amber N. Thornton

Browse all Theses and Dissertations

Early research on the Black family implied an enormous lack of African-American father presence and involvement among African-American fathers. However, more current research negates those findings by highlighting the contributions African-American fathers make when parenting their children (Coley, 2003; Cooper, 2009; Mandara, Murray & Joyner, 2005). In spite of facing unique psychological and social challenges, such as disproportionate levels of poverty, and race related social barriers, such as the invisibility syndrome (Franklin & Boyd-Franklin, 2000), researchers who have studied the African-American father-daughter dyad have discovered that this relationship has many benefits for African-American girls, including cognitive and academic enhancements, reductions …

Carbon-Based Nanostructured Materials As Electrode In Lithium-Ion Batteries And Supercapacitors, Zhuo Yao

Browse all Theses and Dissertations

Carbon-based nancomposites attract much attention as electrode materials in electrochemical energy storage systems due to their low-cost, extraordinary high electrical and thermal conductivity, super high surface area etc. In this research, graphene nanosheets (GNS) and their nanocomposites with manganese oxides (GNS/MnOx) or silicon nanowires (GNS/SiNWs/CF) are studied for their applications in Li-ion batteries and supercapacitors. GNS powders are synthesized via a chemical oxidation of nature graphite followed by appropriate reduction process. GNS/MnOx composites are synthesized rendering MnOx nanoparticles embedded on the surfaces of GNS. SiNWs grown in carbon fibers are mechanically mixed with GNS powders. The impacts of the manganese …

Integrity Monitoring For Multiple Errors In Vision Navigation Systems, Nicholas Allen Baine

Browse all Theses and Dissertations

In aviation applications, navigation integrity is paramount. Integrity of GPS systems is well established with set standards. Vision-based navigation systems have been found to be an adequate substitute for GPS when it is unavailable but are unlikely to be utilized until there is a measure for system integrity. Work has been done to detect the effect of a single measurement pair being corrupted with a bias; however, the measurement geometry varies greatly with the environment. The environment could be sparse in visual features to track, or the environment could be rich with features. With more features, there is a greater …

Impact Of Binaural Beat Technology On Vigilance Task Performance, Psychological Stress And Mental Workload, Elizabeth Ann Shoda

Browse all Theses and Dissertations

Currently, there is only one published study examining the impact of binaural beats on the performance of a laboratory vigilance task, however this study had mixed results and left many questions unanswered. I further examined this phenomenon by using a successive vigilance task, between-subjects design, and a control condition to determine whether beta frequency binaural beats could affect vigilance performance over time and across conditions. I hypothesized that participants listening to beta binaural beats would have more hits and fewer misses on the vigilance task than participants in the control condition. In addition, I hypothesized that participants listening to beta …

Heuristics: Bias Vs. Smart Instrument. An Exploration Of The Hot Hand, Jehangir Cooper

Browse all Theses and Dissertations

Classical perspectives on judgment and rationality view heuristics as erroneous, leading to suboptimal judgments. Conversely, ecological perspectives view heuristics as smart mechanisms that result in good judgments in the face of uncertainty. Our research focused on the hot hand heuristic and examined it using non-linear analysis methods. This research attempted to answer two questions. The first question concerned the applicability of frequency analysis methods for detecting constraints (such as the hot hand) or structure in a time series of binary data, which we attempted to investigate through Monte Carlo simulations. We found that this method was sensitive enough to detect …

The Synthesis Of Haplomyrtin Utilizing The Triisopropylsilyl Protecting Group, William S. Barrow

Browse all Theses and Dissertations

The synthesis of the arylnaphthalene lignan haplomyrtin using vanillin as a starting material is synthesized via: 1) a bromination of vanillin, 4-hydroxy-5-methoxybenzaldehyde, to produce 6-bromovanillin 2) a hydroxyl protection step of 6-bromovanillin with triisopropylsilylchloride to produce 2-bromo-4-triisopropylsilyoxy-5-methoxybenzaldehyde 3) an aldehyde protection step through a cyclic acetal formation using ethylene glycol to produce 2-(2-bromo-4-triisopropylsilyloxy-5-methoxyphenyl)-1,3-dioxolane 4) a lithium for halogen exchange of the doubly protected 6-bromovanillin leads to neucleophilic coupling with piperonal producing 1,3-benzodioxol-5-yl-[5-triisopropylsilyloxy-2-(1,3-dioxolane-2-yl)-4-methoxyphenyl]methanol and 5) an acid catalyzed intramolecular cycloaddition /Diels Alder adduct with dimethyl acetylenedicarboxylate producing dimethyl 1-(1,3-benzodioxol-5-yl)-4-hydroxy-6-methoxy-7-triisopropylsilyloxynaphthalene-2,3-dicarboxylate.

Value Perspective: A Necessary Condition For Photographic Art, Michelle Marie Burdine

Browse all Theses and Dissertations

The conjoined relationship photography has with technology complicates conversations about photography as art because this relationship allows photography to be used interchangeably for practical, social, and commercial purposes, as well as for art. A theory of art for photography is needed in order to accurately separate photographic art from vernacular photography. I show that photography has a unique relationship with technology, which has served to promote the rapid democratization of photography, and that the photographic arts have been treated differently from the greater fine arts. This is especially evident when photographic portraiture is compared with painted portraiture. I offer my …

Co2/Ph Signaling Of Respiratory Control Neurons In The Bullfrog, Lithobates Catesbeianus: Development Of A Comparative Model, Joseph M. Santin

Browse all Theses and Dissertations

The locus coeruleus (LC) in the brainstem senses alterations in CO₂/pH and influences ventilatory adjustments that restore blood gas values to starting levels in bullfrogs (Lithobates catesbeianus). We hypothesized that neurons of the bullfrog LC are sensitive to changes in CO₂/pH and that chemosensitive responses are intrinsic to individual neurons. In addition, we hypothesized putative respiratory control neurons of the bullfrog LC would be stimulated by hypercapnic acidosis within physiological ranges of PCO₂/pH. 84% of LC neurons depolarized and increased firing rates during exposure to hypercapnic acidosis (HA). A pH dose response …

A Geophysical Investigation To Locate Missing Graves Utilizing Ground Penetrating Radar, Electromagnetic, And Magnetic Methods, Jared Wyatt Shank

Browse all Theses and Dissertations

Old cemeteries often have graves that are unmarked because gravestones are missing or degraded and the graves are in areas for which maps or other historical documents are incomplete. This is the case for one cemetery in southwestern Ohio, known as Stevenson Cemetery, which contains graves of Revolutionary War and War of 1812 veterans. The immediate goal of this study is to locate unmarked graves in this cemetery using geophysical techniques. The broader goal is to evaluate three geophysical techniques to determine the effectiveness of each.

The three geophysical techniques evaluated in this study are magnetics, electro-magnetics, and ground-penetrating radar. …

Computational Analysis Of Vortex Structures In Flapping Flight, Zongxian Liang

Browse all Theses and Dissertations

Vortex structures and vortical formation in flapping flight are directly related to the force production. To analyze the connection between vortex structures and aerodynamic performance of flapping flight, we have developed highly efficient algorithms for large-scale flow simulations with moving and deforming bodies. To further understand the underlying mechanisms of force generation caused by the coherent structures of the vortex formation, a new analysis method has been developed to measure the influence of Proper Orthogonal Decomposition (POD) modes on aerodynamic forces.

It is challenging to finish three-dimensional Direct Numerical Simulations (DNS) of insect flight in a limited amount of time. …

The Phylogenetics Of Tachinidae (Insecta: Diptera) With An Emphasis On Subfamily Structure, Daniel J. Davis

Browse all Theses and Dissertations

The parasitoid flies of the Tachinidae family are an important and diverse (>10,000 species) lineage of insects. However, tachinids are not well studied partially due to their confusing classification and taxonomy. DNA sequences were obtained from twenty tribal representatives of Tachinidae, along with eight outgroups in order to phylogenetically reconstruct the superfamilial, subfamilial and tribal relationships of Tachinidae. Seven gene regions of six genes (18S, 28S, COI, CAD, Ef1a, and TPI) were sequenced for each taxon (6214 bp total). Both maximum likelihood and Bayesian methods were used to infer phylogenies. The Sarcophagidae and Oestridae were usually reconstructed as monophyletic. …