Digital Commons Network^™

Computational Investigation Of Optimal Heavy Fuel Direct Injection Spark Ignition In Rotary Engine, Asela A. Benthara Wadumesthrige

Browse all Theses and Dissertations

The main objective of this computational study is to investigate the optimum injection and spark parameters for the direct injection spark ignition (DISI) Wankel rotary engine using diesel fuel. Currently only port fuel injected gasoline rotary engines are available in the automotive industry. Compared to reciprocating type engines rotary engine is mechanically simple, less vibrate, have higher power to weight ratio and achieve better performance at high rpm. Due to the inherent low fuel efficiency of rotary engine and increasing gas prices, application of the rotary engine in conventional automobiles is decreasing. This project seeks to introduce DISI technology to …

A Probabilistic Assessment Of Vertebral Cortical Bone Fracture Of Intraosteonal Structures, Isaac Graham Mabe

Browse all Theses and Dissertations

Cortical bone is a porous structure. The presence of these pores creates the possibility of a local overstressed area that has the likelihood of premature failure. Some failure modes of the vertebral endplates, for example subsidence which occurs at rates as high as 77 percent, can be better predicted with further understanding of failure mechanisms and the ability to predict those mechanisms. A probabilistic assessment of the pore size and its contribution to the fracture toughness has not been investigated in the cortical shell of the vertebral endplates. This research develops a probabilistic model that has the ability to determine …

Turnover Reasons And Employee Attitudes: Examining Linkages Within The Framework Of Behavioral Reasoning Theory, Gregory D. Hammond

Browse all Theses and Dissertations

This study investigated the relationship between individuals' reasons for leaving their former employers (e.g., inadequate pay) and relevant attitudinal variables (e.g., attitudes regarding pay and other compensation). The role of attitudes as a mediator of the relationship between reasons and intentions was also investigated. Finally, the relationship between reasons, attitudes, and reemployment in the same industry was investigated. Results from an archival sample of former employees (n = 5044) from 8 small to medium-sized companies in a variety of industries indicated mixed support for the hypotheses. Implications and directions for future research were discussed.

Surface Stress Sensors For Closed Loop Low Reynolds Number Separation Control, Christopher R. Marks

Browse all Theses and Dissertations

Low Reynolds number boundary layer separation causes reduced aerodynamic performance in a variety of applications such as MAVs, UAVs, and turbomachinery. The inclusion of a boundary layer separation control system offers a way to improve efficiency in conditions that would otherwise result in poor performance. Many effective passive and active boundary layer control methods exist. Active methods offer the ability to turn on, off, or adjust parameters of the flow control system with either an open loop or closed loop control strategy using sensors. This research investigates the use of a unique sensor called Surface Stress Sensitive Film (S3F) in …

Weapon Engagement Zone Maximum Launch Range Approximation Using A Multilayer Perceptron, Brian Michael Birkmire

Browse all Theses and Dissertations

This thesis investigates the use of an artificial neural network (ANN), in particular a Multi-Layer Perceptron (MLP), to perform function approximation on truth data representing a weapon engagement zone's (WEZ) maximum launch range. The WEZ of an air-to-air missile represents the boundaries and zones of effectiveness for a one-vs-one air-to-air combat engagement [13]. The intent is for the network to fuse table lookup and interpolation functionality into a physically compact and computationally efficient package, while improving approximation accuracy over conventional methods. Data was collected from simulated firings of a notional air-to-air missile model and used to train a two layer …

Interrogation Of The Distal Gut Microbiota Of Healthy Adolescents And Those With Irritable Bowel Syndrome, Laura J. Rigsbee

Browse all Theses and Dissertations

The human-associated microbiota has been the focus of much current research, with the microbiota inhabiting the gastrointestinal tract of particular interest. These organisms play many roles in human health and well-being. However, shifts in the composition of the intestinal microbiota have been associated with diseases such as irritable bowel syndrome, inflammatory bowel disease, and colon cancer. Several recent studies have reported on the distal gut microbiota composition of healthy adults and those with IBS, while there is a lack of studies devoted to adolescents. This study utilized a custom-designed Affymetrix Microbiota Array capable of detecting 775 phylo-species of intestinal bacteria …

Design And Development Of A Fall Detection Device With Infrared Receiving Capabilities, Ammari Ramzi

Browse all Theses and Dissertations

Fall related injuries are the leading cause of death and hospitalization among the elderly. Falls among older people become a major problem facing hospitals and nursing homes. In this study we put an effort to design a wireless device capable of detecting falls with the hope that this study will provide a path towards better healthcare monitoring and better independent living for the elderly.

In this project I showed how the fall detection device can be interfaced with different systems to achieve functionality without adding extra cost. For seniors who prefer to stay at their homes and live independently, the …

Aquaporin 4 Expression And Distribution During Osmotic Brain Edema And Following Chronic Treatment Of Desipramine, Sergei Alexander Robinson

Browse all Theses and Dissertations

Osmotic brain edema or chronic treatment with desipramine alters brain water permeability. In this study we investigated aquaporin 4 expression and distribution in these two conditions. Brain edema development was induced by intraperitoneal water injection. Blood serum osmolality decreased from 296 ± 1 mOsm to 278 ± 2 mOsm within 15 min. Cerebral cortex water content increased from 79.8 ± 0.2 % to 81.3 ± 0.5% during 120 min of this hyposmotic exposure. Aquaporin 4 immunostaining intensity at the astrocytic endfeet increased in water injected animals from 2.6 ± 0.04 intensity unites (IU) to 3.2 ± 0.21 IU, while total …

Response Of Monovalent Cation Transporters To Pro-Apoptotic Protein Kinase C Modulators In Human Lens Epithelial Cells, Michael Anthony Lepera

Browse all Theses and Dissertations

Protein kinase inhibition by staurosporine causes apoptotic volume decrease involving potassium (K) channels in immortalized human B3 lens epithelial cells (LECs). Here, the effect of two pro-apoptotic protein kinase C (PKC) inhibitors [12-O-tetradecanoyl-phorbol-13-acetate (TPA) and chelerythrine (CET)] were studied on membrane K transport in a fetal human LEC line (FHL124) by western blotting, immunofluorescence, ion flux, ATP, apoptosis, and biotinylation assays. Long term TPA exposure (0-6 h) inhibited 75% of Na-K-2Cl cotransport (NKCC). In contrast, short term (0-20 min) exposure to 50 μM CET reduced Na/K pump and NKCC by >90% and >70%, respectively, without retrieval from the membrane into …

Differentiation Of Megakaryocytes/Platelets And Neurons From Human Endometrial Stromal Progenitor Cells, Jinju Wang

Browse all Theses and Dissertations

Human endometrium is a high dynamic tissue that contains stem/progenitor cells. These endometrial stromal progenitor cells (hESCs) have been differentiated into a number of mesodermal lineages. There is limited information on differentiating hESCs into neurons, and no information on differentiating hESCs into megakaryocytes (MKs) and platelets (PLTs). The aim of this work was to investigate the possibility of differentiating hESCs into two distinct lineages: MKs, with subsequent PLT formation, and neurons.

We isolated hESCs from human endometrial tissue and cultured the cells for 4-6 passages. Before each differentiation experiment, the purity of hESCs was confirmed by flow cytometry analysis which …

Personality And Simulated Employment Decisions In Perceived Gay And Lesbian Applicants, Megan Brianne Morris

Browse all Theses and Dissertations

Currently, there is no research that assesses how individual's perceptions of personality and other characteristics in gay male and lesbian applicants affect employment decisions. I examined individuals' perceptions of personality in gay and lesbian applicants and the effect of these perceptions on employment outcomes. I hypothesized that individuals would prescribe gender atypical traits to gay male and lesbian applicants, and that qualification ratings for these applicants would depend on job-type match with the applicants' gender atypical traits. In the current study, I used a sample of undergraduate students. Each participant evaluated a resume that potentially contained cues reflecting a homosexual …

Parallel Sorting On Multi-Core Architecture, Wei Wang

Browse all Theses and Dissertations

With the limitations given by the power consumption (power wall), memory wall and the instruction level parallelism, the computing industry has turned its direction to multi-core architectures. Nowadays, the multi-core and many-core architectures are becoming the trend of the processor design. But how to exploit these architectures is the primary challenge for the research community. To take advantage of the multi-core architectures, the software design has undergone fundamental changes.

Sorting is a fundamental, important problem in computer science. It is utilized in many applications such as databases and search engines. In this thesis, we will investigate and auto-tune two parallel …

An Implicit High-Order Spectral Difference Method For The Compressible Navier-Stokes Equations Using Adaptive Polynomial Refinement, Caleb J. Barnes

Browse all Theses and Dissertations

A high/variable-order numerical simulation procedure for gas dynamics problems was developed to model steep grading physical phenomena. Higher order resolution was achieved using an orthogonal polynomial Gauss-Lobatto grid, adaptive polynomial refinement and artificial diffusion activated by a pressure switch. The method is designed to be computationally stable, accurate, and capable of resolving discontinuities and steep gradients without the use of one-sided reconstructions or reducing to low-order. Solutions to several benchmark gas-dynamics problems were produced including a shock-tube and a shock-entropy wave interaction. The scheme's 1st-order solution was validated in comparison to a 1st-order Roe scheme solution. Higher-order solutions were shown …

Fusion Of Video And Multi-Waveform Fmcw Radar For Traffic Surveillance, Nicholas C. Gale

Browse all Theses and Dissertations

Modern frequency modulated continuous wave (FMCW) radar technology provides the ability to modify the system transmission frequency as a function of time, which in turn provides the ability to generate multiple output waveforms from a single radar unit. Current low-power multi-waveform FMCW radar techniques lack the ability to reliably associate measurements from the various waveform sections in the presence of multiple targets and multiple false detections within the field-of-view. Two approaches are developed here to address this problem.

The first approach takes advantage of the relationships between the waveform segments to generate a weighting function for candidate combinations of measurements …

Anthropometric Analysis Of The Cervical Spine, Susan Hueston

Browse all Theses and Dissertations

An understanding of the dimensional anatomy of the cervical spine is necessary in order to help diagnose disease, deformity, injury, and device development. Previous investigation has been completed utilizing cadavers, X-rays and other imaging techniques. This research utilized computer tomography images from the trauma registry at Miami Valley Hospital in Dayton, Ohio to complete an anthropometric study of the cervical spine. Linear mathematical models were developed to investigate the relationships present in the dimensional anatomy of the cervical spine. New measurements were completed on subjects of both Caucasian and African American descent and of both genders. An approximation of the …

A Study Of The Aerodynamic Behavior Of A Nrel Phase Vi Wind Turbine Using The Cfd Methodology, Yen-Pin Chen

Browse all Theses and Dissertations

Wind energy is an abundant natural resource that people have been trying to tap in recent decades. More and more wind turbines are being built to solve the world's energy shortage problem. For a wind turbine, power extracted from the wind by the rotor and the torque applied to the wind turbine blades are important issues in the design process. Thus there is a need to predict the performance of wind turbine blades using computer modeling. This work shows the results of a computational fluid dynamic simulation developed to predict the air flow field and associated aerodynamic quantities around the …

Investigation Of Variability In Cognitive State Assessment Based On Electroencephalogram-Derived Features, Samantha Lokelani Crossen

Browse all Theses and Dissertations

To implement adaptive aiding in modern aviation systems there is a need for accurate and reliable classification of cognitive workload. Using electroencephalogram (EEG)-derived features, it has been reported that an Artificial Neural Network (ANN) can achieve 95% or higher classification accuracy on the same day for an individual operator, but only 70% or less on a different day. To gain a further insight into this discrepancy, data from a previous study was utilized to study the classification variability. The EEG-derived features were first calculated by spectral power estimation. The variability was then analyzed by performing cognitive workload classification in which …

Large Scale Distributed Semantic N-Gram Language Model, Yuandong Jiang

Browse all Theses and Dissertations

Language model is a crucial component in statistical machine translation system. The basic language model is N-gram which predicts the next word based on previous N-1 words. It has been used in the state-of-the-art commercial machine translation systems over years. However, the N-gram model ignores the rich syntactic and semantic structure in natural languages. We propose a composite semantic N-gram language model which combines probabilistic latent semantic analysis model with N-gram as a generative model. We have implemented the proposed composite language model in a super-computer with thousand processors that is trained by 1.3 billion tokens corpus. Comparing with simple …

Effect Of Material Anomalies On Fatigue Life Of Turbine Disks, Jace A. Carter

Browse all Theses and Dissertations

There is an economic need to extend the fatigue life of turbine engine rotor disks. The probability of failure during the operation life must be quantified as components remain in service beyond their traditional safe-life limit. Fracture mechanics based probabilistic methods are utilized to predict the probability of failure of components containing manufacturing and fatigue anomalies. Total fatigue life is defined in terms of crack initiation and propagation phases. A micromechanical initiation model uses material properties at the micro-scale to characterize the initiation phase, while short and long fatigue-crack growth models predict the crack propagation phase. A Monte Carlo simulation …

Selective Automatic Image Feature Detection, Aijing Wang

Browse all Theses and Dissertations

To allow automatic assessment of computed tomography (CT) images of long bones, the identification of the location of regions of interest is important. The distance between the distal and proximal styloids may act as reference points for bone length; however, the locations of the distal and proximal growth plates represent further important reference features. The current methods to locate these feature positions are manual. In this project, we attempt to find these feature positions automatically.

A CT data set was split into two subsets, a development set, and a validation set. We first extracted basic information from the stack and …

Semi-Supervised Contrafold For Rna Secondary Structure Prediction: A Maximum Entropy Approach, Jianping Feng

Browse all Theses and Dissertations

A novel probabilistic discriminative model based on conditional random fields, CONTRAfold, has recently been proposed for single sequence RNA secondary structure prediction. By incorporating most of the features which closely mirror the local interaction terms of thermodynamics-based models, the CONTRAfold model has outperformed both probabilistic and physics-based techniques, and received the highest single sequence prediction accuracies. CONTRAfold, like most other RNA secondary structure prediction techniques, requires a collection of RNA sequences with known secondary structure to serve as training data for the algorithm. Manual annotation of RNA sequences is both expensive and time-consuming, and there remains a great deal more …

Niyama Based Taper Optimizations In Steel Alloy Castings, Daniel A. Gorsky

Browse all Theses and Dissertations

In the casting process, regions of shrinkage porosity can be reduced or eliminated through the implementation of taper, or small angled additions of mass on the boundaries of the part design, before risers are placed on the casting. Taper supplements the effect of risers so that a smaller riser volume is necessary to make a casting sound. Typically, taper is determined for a casting by using industry guidelines that were developed for simple two-dimensional simplifications of a complex casting. There is no accepted method of defining taper directly on part geometry aside from using expert opinions to make final decisions …

Process Sequencing For Fatigue Life Extension Of Large Scale Laser Peened Components, Thomas Joshua Spradlin

Browse all Theses and Dissertations

Mechanical surface enhancement techniques have been used to successfully increase the fatigue life of metallic components. These techniques impart compressive surface residual stresses that reduce the tensile stresses experienced during service loading. Laser Peening (LP) is a surface enhancement technique that uses high intensity, short duration laser pulses to create plastic shockwaves in metallic components. Experimental investigations and limited simulation studies have been conducted to determine the effects on the fatigue life of simple coupons when key LP parameters are varied. Used primarily in the aerospace and biomedical engineering fields, LP has been limited to industries that can afford its …

Optimizing Memory Cost With Loop Transformations, Hailong Shi

Browse all Theses and Dissertations

Embedded systems are usually constrained in terms of timing, power, and memory. Many embedded applications, especially in the multi-media and telecom domains, are inherently data dominant. These embedded DSP applications usually exhibit intensive computations in the form of multi-level loops. The performance of these embedded DSP applications mainly depends on the code quality of the loops and the memory hierarchy design. During the design phase of the embedded system, it is important to estimate the overall storage requirement to guide the memory system design and take advantage of the memory system by program transformations and loop transformations.

Loop transformations including …

Methylmercury In Mosquitoes: Impact Of A Large Coal-Fired Power Station In Central Ohio, Matthew J. Konkler

Browse all Theses and Dissertations

Emissions from coal-fired utilities are the major anthropogenic source of mercury (Hg) to the atmosphere. Because emitted Hg may be deposited near the source, there are concerns on levels of toxic monomethylmercury (MeHg) in local biota. We investigated the potential impact of a large Hg-emitting (> 500 kg Hg y-1) coal-fired power station on MeHg levels in mosquitoes near the Conesville power station in central Ohio. Mosquitoes were sampled with CO2-baited traps at 23 locations within a 60 km radius of the utility and at three reference sites distant from Hg combustion sources. MeHg in mosquitoes within a 30-km radius …

Discretion Without Choice: Sexual Offender Legislation And Judicial Discretion, Jonathan C. Varhola

Browse all Theses and Dissertations

In a historically recent development, sex offenders have arguably become a focal point of attention in discourses surrounding sexuality, childhood, and crime. Much research has been accomplished regarding the treatment and recidivism of such offenders, as well as consequences of sex offender legislation and policy initiatives. However, little research has been done regarding specifically the discretion of criminal justice agency professionals involved in the day-to-day handling of these types of cases. This study focused on the effects of such policies on judicial discretion, as measured by sentencing outcomes. Data was collected from publicly available internet sexual offender registries and county …

Role Of Hyperglycemia And Aldosterone On Renal Ace2 And Albuminuria In Db/Db Mice, Harshita Chodavarapu

Browse all Theses and Dissertations

Diabetic nephropathy (DN) is one of the microvascular complications of type II diabetes and a leading cause for the development of end stage renal disease. Renin angiotensin system (RAS) plays a pivotal role in the development and progression of diabetic nephropathy. Hyperglycemia activates RAS and increases tissue and circulating levels of angiotensin II (Ang II) and aldosterone. A new component of RAS, angiotensin converting enzyme 2 (ACE2), has been shown to be renoprotective in early stages of diabetes. The aim of this study is to test the hypothesis that strict glycemic control using rosiglitazone or treatment with mineralocorticoid receptor (MR) …

Near Equilibrium Dissolution Of Calcite Using A Flow-Through Reactor (Ftr), Michael Mante

Browse all Theses and Dissertations

In mineral dissolution reactions, surface morphologies play important roles particularly in near equilibrium fluids where generation of new sites of reactivity (e.g., pit nuclei) is thermodynamically disfavored. Following CO₂ injection in geologic formations, dissolution of primary carbonate minerals and crack-sealing cements will occur. The impact of these reactions on fluid chemistry requires better understanding of the reaction kinetics of major minerals at close-to-equilibrium conditions. Initial investigations have focused on quantifying calcite dissolution using short residence time (~ 10 min) flow through reactors to obtain dissolution rates at 60°C, pH = 8.33 and Pco₂ = 3.8 x 10^{-4 …}

A Comparison Of Work-Specific And General Personality Measures As Predictors Of Ocbs And Cwbs In China And The United States, Qiang Wang

Browse all Theses and Dissertations

Previous studies on frame-of-reference effects have focused on domain-specific personality measures as predictors of performance in North America. The current study expands on this research by comparing work-specific and general personality as predictors of CWBs and OCBs in an East Asian culture (i.e., China). Consistent with the literature on frame-of-reference effects in personality assessment, I found that three Big Five personality dimensions, including agreeableness, conscientiousness, and emotional stability, were significantly related with OCBs and CWBs. Also, use of a frame of reference that is conceptually relevant to the criterion led to increased validity as a result of the decrement in …

Multipurpose Map Designs For Gps Surface-Vehicle Navigation: Spatial Knowledge And Advisory Functions, Caitlan A. Rizzardo

Browse all Theses and Dissertations

Current car navigation systems primarily utilize track-up maps with spatial turn arrows, which facilitate turn decision-making but do not facilitate acquisition of spatial knowledge of the region. North-up maps do facilitate acquisition of regional spatial knowledge, however, these displays sometimes have arrows heading in directions misaligned with a driver's forward view, such as when the car is heading south. Drivers have difficulty making turn decisions in these misaligned maps because of stimulus-response reversals (Chan and Chan, 2005; Levine, 1982; Levine, Marchon and Hanley, 1984; Montello, 2010). A new display was designed using a fixed orientation north-up map and added a …