Engineering Commons^™

Investigation Of Auxiliary Winding Harmonic Resonance Phenomena In Single Phase Induction Motors, Gaurav Singh

All Theses

In recent years, the proliferation of single phase power electronics based loads has given rise to a number of power quality issues in the power grid. Harmonics in voltage and current waveforms are one of the biggest problems in this family of power quality issues. Until some years back, power system utilities did not consider harmonics due to small single phase loads to be a big problem. In fact, only large loads were considered as potential hotspots for power quality problems. However, the advent of compact fluorescent lamps (CFLs), personal computers and consumer electronic devices, which utilize rectifier front ends, …

Reverse Osmosis Desalination With Integrated Compressed Air Energy Storage: Conceptual Design And Modeling, Pooja Mahajan

All Theses

Growing fresh water needs have led to an interest in water desalination using reverse osmosis (RO) membranes. Energy consumption has a large share in the expenses incurred to drive a reverse osmosis desalination system. With depleting fossil fuel reserves, tapping renewable sources of energy is a promising alternative to meet the energy requirements. Wind power coupled to an RO desalination system is a potential means of delivering clean water using sustainable energy. This work investigates modeling of a conceptual wind-energy-driven RO desalination system that is made possible because of an air-pressure energy storage mechanism. Bench-scale experiments were performed on an …

Estimating Water Flux And Storage Using Displacement Measurements In Saprolite At Depth, Clay Freeman

All Theses

Water storage in the soil is important for many hydrologic problems, but measuring how the storage changes at an appropriate scale remains a challenge. The objective of this thesis is to evaluate the feasibility of estimating change in water content in soil by measuring vertical displacement in underlying soils. This approach is appealing because the averaging volume of the displacement scales with the depth at which the measurements are taken. This should result in measurements of changes in soil moisture that are averaged over regions 10s to 100s of meters across, a measurement scale that is much larger than that …

A Laboratory Study Of Levee Scour From Overtopping Storm Waves And Protection For Robust Desgins, Earnest Johnson

All Theses

Levee failure due to scouring has been a prominent occurrence among intense storm surges and waves, giving rise to the implementation of various scour protection measures over the years. Several experiments were performed on a model levee on either bare levee soil or with a scour protection measure covering the soil. The purpose of this study is to breakdown the dynamics of levee scour due to overtopping waves and suggest efficient methods in reducing the amount of scour. The levee soil was made up of a sand-clay mixture and placed in a laboratory wave tank that created a constant wave …

Assessing Anaerobic Bio-Oxidation Of Vinyl Chloride And Ethene, Ademola Bakenne

All Theses

Perchloroethene (PCE) and trichloroethene (TCE) are two of the most commonly used chlorinated solvents around the world. These compounds and their dechlorination daughter products have become the most prevalent organic contaminants found in a majority of hazardous waste sites in the United States. Since implementation of traditional remediation methods would cost hundreds of billions of dollars, there has been tremendous interest in bioremediation as a low cost alternative to achieving remedial goals. Anaerobic reductive dechlorination is the most prevalent form of bioremediation in most locations. The ultimate daughter products from reductive dechlorination of PCE and TCE are ethene and ethane, …

Fault Analysis Of An Unbalanced Distribution System With Distributed Generation, Parimal Saraf

All Theses

In recent years there has been a lot of emphasis on renewable power integration due to environmental issues and to lower the dependence on fossil fuels. The presence of renewable sources in the distribution systems adds complexity to the calculation of the power flows and hence has a direct impact on the short circuit calculations, protection and control. The presence of unbalance in distribution systems worsens the situation since the three phase voltages and currents are no longer equal in magnitude and 120 degrees phase shifted.
This thesis involves a fault study in a 14-bus distribution system with integrated wind …

Load Carrying Capacity Assessment Of A Masonry Dome, Tun Li

All Theses

This thesis first establishes a semi-empirical relationship to estimate the reduction in load carrying capacity of a masonry dome due to damage by exploiting deviations in the fundamental natural frequency. A macro finite element model of the dome is developed and calibrated using both non-destructive vibration measurements and destructive load-displacement measurements up to failure. The macro-model is then executed to simulate incremental development of cracks. The first natural frequency and remaining load carrying capacity of the dome are monitored to define a semi-empirical relationship, which is ultimately generalized for spherical domes with varying span-to-height ratios.
Subsequently, in order to numerically …

The Effect Of Granular Activated Carbon Pretreatment And Sand Pretreatment On Microfiltration Of Greywater, David Christopher

All Theses

Around the world, water scarcity is driving people to practice water reuse. One form of water reuse is the recycling of greywater, which is household wastewater excluding toilet waste. With adequate treatment, greywater may be recycled onsite for applications that do not require potable water, such as irrigation or toilet flushing. Membrane filtration (including microfiltration (MF)) is one option for greywater treatment. The small footprint, modular nature, and predictable performance of MF make it an attractive option. However, direct MF of greywater can lead to rapid membrane fouling. This thesis investigated two possible pretreatments for reducing membrane fouling and improving …

Effects Of Physiological Dynamic Compression Loading On Gold Nanoparticle Permeation Of Articular Cartilage, Britton Mccaskill

All Theses

Articular cartilage is essential part of the human body that aids in support and locomotion. It has unique biochemical and biomechanical properties that allow it to act as a shock absorber to disperse and distribute loading of the joints. However, it has a limited capacity to repair itself because it is not vascularized and must receive its nutrients from the surrounding synovial fluid. Articular cartilage damage can lead to many pathological conditions, including osteoarthritis. Currently, there are many surgical treatment methods that repair some of the damage if it is localized, but for widespread degradation seen in osteoarthritis, there are …

Determining The Proper Point Size For Display Type On Packaging, Joanna Fischer

All Theses

Through the use of a preference test, the proper point size of display text on a package was evaluated in relation to a package's proportions. The test involved the examination of packaging images displaying the product or brand name in various point sizes by 150 participants who were then asked to choose the option they most preferred. The participants were then provided with a post-survey intended to gather additional information regarding potential preference motives.
The primary purpose of this study was to determine the most preferred display type size of a package based on its relationship with the package's proportions. …

Numerical And Reliability Analysis Of Gravity Cantilever Retaining Walls Backfilled With Shredded Tires Subjected To Seismic Loads, Eleanor Huggins

All Theses

Shredded tires have been considered as a suitable alternative to conventional sand and gravel backfill materials as they offer benefits from their significantly lower unit weight, reductions in the cost of materials and construction, and because they utilize a common and potentially hazardous waste material. This research addresses some gaps in previous research in the implementation of shredded tires in this capacity by examining variation in material properties through a reliability analysis, developing an improved design technique for retaining walls tailored to shredded tire fills, and simulating how shredded tire backfill behaves in conjunction with retaining walls when subject to …

Developing A Greenhouse Gas Emissions Calculation Tool For Water Utilities, Anthony Hampton Johnston

All Theses

The issue of climate change has led to an increased emphasis on sustainable practices in almost every facet of our lives. For water utilities, this has increased scrutiny on energy use. Although traditionally viewed solely in financial terms, energy use is also the primary source of greenhouse gas (GHG) emissions from water utilities. The emerging concern over GHG emissions coincides with potential federal legislation and regulation by the Environmental Protection Agency (EPA). In order for water utilities to determine their GHG emissions, guides and tools must be made readily available. Information to educate water utilities about their GHG emissions is …

Tribiology Of Engineered Surfaces In Aggressive Environments, Nathan Phillip Mitchell

All Theses

To improve the performance of sliding systems, surface modifications and coatings are often applied to opposing surfaces. This thesis focuses on characterizing two tribo-systems (DLC-DLC and steel micropatterns-flat) under their predicted application environments. The first section is focused on friction testing of micropatterned surfaces for orthopaedic device design, the second section elucidates how the sliding of diamond-like-carbon (DLC) coatings changes with temperature and humidity. The experimental design and major results of these sections are as follows.

(1) The use of micropatterning to create uniform surface morphologies has been cited as yielding improvements in the coefficient of friction during high velocity …

An Electromagnetic Energy Harvester For Powering Consumer Electronics, Xiyuan Liu

All Theses

This thesis introduces an electromagnetic vibratory energy harvester to power consumer electronics by generating electricity from the strides taken during walking or jogging. The harvester consists of a magnetic pendulum oscillating between two fixed magnets. The pendulum behaves similar to a rotor in a DC generator, while the fixed magnets, which are poled opposite to the pendulum, provide magnetic restoring forces similar to mechanical springs. When attached to a person's arm, the swinging motion subjects the magnetic pendulum to base excitations. Consequently, the pendulum oscillates near a stator which has three poles of wound copper coils. The motion of the …

Optimization Of Processing Parameters For As2se3 Glass For Low Loss, High Strength Fibers, Baptiste Giroire

All Theses

Chalcogenide glasses have been widely studied due to their extraordinary transparency in the infrared (IR) region from 0.5 to 20 μm. This transparency combined with excellent thermo-mechanical properties, makes them ideal candidate for infrared optics including IR fiber optic applications. However, such non-oxide glasses generally exhibit low mechanical strength, as compared to their oxide counterpart, which are based on covalently bonded metal-oxygen species. In addition to mechanical robustness, low optical loss (hence low impurity content) is required for most IR optical materials, including the one in this study, amorphous arsenic tri-selenide, As2Se3. In this effort, As2Se3 glass was investigated and …

Component Mode Synthesis Approach For Quantum Mechanical Electrostatic And Transport Analysis Of Nanoscale Structures And Devices, Zhe Gao

All Theses

As the dimensions of commonly used semiconductor devices have shrunk into nanometer regime, it is recognized that the influence of quantum effects on their electrostatic and transport properties cannot be ignored. In the past few decades, various computational models and approaches have been developed to analyze these properties in nanostructures and devices. Among these computational models, the Schršdinger-Poisson model has been widely adopted for quantum mechanical electrostatic and transport analysis of nanostructures and devices such as quantum wires, metal-oxide-semiconductor field effect transistors (MOSFETs) and nanoelectromechanical systems (NEMS). The numerical results allow for evaluations of the electrical properties such as charge …

Investigation Of Prototype Roles In Conceptual Design Using Case Study And Protocol Study Methods, Timothy Hess

All Theses

Prototypes play an important role in the engineering design process. Engineering design textbooks often discourage the use of prototypes early in the design process, citing past research on prototypes in engineering design has focused describing and classifying the prototypes themselves. The gap in this research is the investigation of prototyping processes. While researchers have studied the characteristics of different prototypes and in some cases have tried to tie characteristics to the outcomes of the design process, the actual prototyping activities and the process of building and using the prototypes has not been studied in detail. The work presented in this …

Socialq&A: A Novel Approach To Notifiying The Correct Users In Question And Answering Systems, Nikhil Vithlani

All Theses

Question and Answering (Q&A) systems are currently in use by a large
number of Internet users. Q&A systems play a vital role in our daily life as
an important platform for information and knowledge sharing. Hence, much
research has been devoted to improving the performance of Q&A systems,
with a focus on improving the quality of answers provided by users, reducing
the wait time for users who ask questions, using a knowledge base to provide
answers via text mining, and directing questions to appropriate users. Due
to the growing popularity of Q&A systems, the number of questions in the
system …

Enzyme Actuated Bioresponsive Hydrogels, Andrew Wilson

All Theses

Bioresponsive hydrogels are emerging with technological significance in targeted drug delivery, biosensors and regenerative medicine. Conferred with the ability to respond to specific biologically derived stimuli, the design challenge is in effectively linking the conferred biospecificity with an engineered response tailored to the needs of a particular application. Moreover, the fundamental phenomena governing the response must support an appropriate dynamic range and limit of detection. The design of these systems is inherently complicated due to the high interdependency of the governing phenomena that guide the sensing, transduction, and the actuation response of hydrogels. To investigate the dynamics of these materials, …

Stabilization Of Extracellular Matrix Components In Bioprosthetic Heart Valves Using Neomycin And Pentagalloyl Glucose Enhanced Crosslinking, Daniel Tripi

All Theses

Bioprosthetic heart valves (BHVs) fail within 12-15 years of implantation due to limited durability. This limits their application to elderly population. Younger patients with contraindications for long-term anticoagulant therapy necessary for mechanical heart valves may also receive BHVs. Investigation into improving valve durability can lead to longer implant life, increased quality of life for patients receiving BHVs, and a broadened patient demographic.
Current BHVs are chemically treated with glutaraldehyde (GLUT) to stabilize collagen via chemical crosslinking and to reduce tissue antigenicity. GLUT fails to adequately stabilize elastin and glycosaminoglycans (GAGs), essential extracellular matrix components for valve function and durability. Degradation …

Continuum Limbed Robots For Locomotion, Alper Mutlu

All Theses

This thesis focuses on continuum robots based on pneumatic muscle technology. We introduce a novel approach to use these muscles as limbs of lightweight legged robots. The flexibility of the continuum legs of these robots offers the potential to perform some duties that are not possible with classical rigid-link robots. Potential applications are as space robots in low gravity, and as cave explorer robots.
The thesis covers the fabrication process of continuum pneumatic muscles and limbs. It also provides some new experimental data on this technology. Afterwards, the designs of two different novel continuum robots - one tripod, one quadruped …

Development And Characterization Of Shellac-Hydroxypropyl Methyl Cellulose Composite Films With Acid Catalyst, Sana Asrar

All Theses

The objective of this research was to develop a shellac-hydroproyl methyl cellulose (Sh-HPMC) composite film with enhanced water vapor barrier. Citric acid (CA) was used as an acid catalyst, to promote miscibility between HPMC and shellac. In a preliminary test, three different concentrations of CA (1000:1, 200:1, 100:1) were tested to identify the best Sh:CA ratio. Based on the Water vapor permeability properties and mechanical properties, Sh-CA (1000:1 ratio) had the most enhanced water vapor barrier and the lowest reduction in tensile strength compared to the pure HPMC film (control). In the later part of the research, the effect of …

Evaluation Of Dichloromethane As An Electron Donor For Reductive Dechlorination Of Tetrachloroethene To Ethene, Yogendra Kanitkar

All Theses

Tetrachloroethene (PCE) and trichloroethene (TCE) are the predominant contaminants at hazardous waste sites in the United States. Although less prevalent, dichloromethane (DCM) is also found at a number of sites. EPA classifies PCE and DCM as likely to be carcinogenic in humans by all routes of exposure, while TCE is classified as carcinogenic to humans by all routes. At some sites, releases of PCE, TCE and DCM comingle in the groundwater. Field evidence from one such site in California suggests that DCM is used as the electron donor for reductive dechlorination of TCE. Nevertheless, definitive evidence that DCM can serve …

Historical Integration Of Remote Sensing Data: Can Gis Extract Information From Grayscale Aerial Photographs?, Kristina Robertson

All Theses

There have been many changes in land management policies of the National Forest system over the past 100 years. Changes in policy related to law, population growth and economics directly cause changes in land cover. Global land cover changes are occurring at such a pace and magnitude that they are affecting Earth system functioning (Lambin et al., 2001). The analysis of land cover changes plays a key role in understanding several environmental phenomena, resulting in a need for objective and comparable land cover maps (Gennaretti et al., 2011). Advances in remote sensing and Geographic Information Systems (GIS) have modernized land-use …

The Effect Of Food Ingredients On The Oxygen Barrier Properties Of Retort Materials, Amanda Ward

All Theses

An unexplored area in research is addressing how retorted food ingredients interact with retort packaging's oxygen barrier. Ten common food ingredients (whey protein isolate, soy protein isolate, bovine gelatin, fish gelatin, high molecular weight fish gelatin, water, air, oil, potato starch, and hydroxypropyl methylcellulose) were assessed to find their effect on the barrier properties of CPP, PET, and high barrier commercial retort pouches. OxySense Gen III 300 and Mocon OxTran 2/21 were used to evaluate the samples. CPP pouches were first assessed with the OxTran 2/21 and indicated that treatments affected the OTR's of the film materials. However, results from …

Measuring Ligand Exchange On The Surface Of Gold Nanoparticles: A Study Of Competitive Binding Of Ligands Utilizing Fluorescent Resonance Energy Transfer, Daniel D'Unger

All Theses

This study was conducted to track ligand exchange on the surface of metallic nanoparticles in order obtain a better understanding of binding strength of various functional groups. This study develops groundwork for further understanding ligand exchange as nanoparticles transition from engineered to natural systems. A problem exists in knowing the fate of these particles if they are released into natural systems, by accident or with intent. To gain a better understanding of what may occur we look at the binding strength of different ligands. This is done to gain knowledge of the possibility of displacement of ligands occurring in the …

Biomass And Lipid Production From Heterotrophic And Mixotrophic Fed-Batch Cultivations Of Microalgae Chlorella Protothecoides Using Glycerol, Shwetha Sivakaminathan

All Theses

Chlorella protothecoides is a microalga that can grow both photo-autotrophically and/or heterotrophically under different culture and environmental conditions. In this study both the heterotrophic growth and mixotrophic growth have been conducted. The heterotrophic experiments were conducted completely in the dark while the mixotrophic experiments had the dark cycles with periodic light exposure. The aim of the study was to independently understand the effect of each mode on biomass and lipid yields.
For the heterotrophic experiments, glycerol was used as an external organic carbon source while yeast extract was used as the nitrogen source. The carbon and nitrogen source were added …

Functionalized Nanoparticles As Removable Coatings For Reverse Osmosis Membranes, Megan Smith

All Theses

Reverse osmosis (RO) desalination is increasingly used to produce potable water throughout the world. Despite their promising abilities, membrane filtration processes are limited by fouling. Fouling is a broad term for organics, inorganics, colloids and organisms that interact physically, chemically, or biologically with the membrane surface, resulting in reduced flux and shortened membrane lifespan. There is potential to create a snakeskin-like barrier between the membrane and foulants by electrostatically binding a coating material to the membrane that can be released by pH manipulation, removing foulants in the process. The feasibility of using functionalized nanoparticles as removable adsorptive coatings on RO …

Vibration And Acoustic Performance Of In-Plane Honeycomb Sandwich Panels, Xiao Gong

All Theses

Sandwich panel structures constructed with cellular honeycomb cores allow for control of acoustic performance due to their ability to optimize effective orthotropic material properties with changes in cell geometry. By modification of topology and geometric parameters of a unit cell, desirable effective properties can be obtained and used to design lightweight structures with reduced vibration and increased sound transmission loss properties. Thus investigating the relation between the geometric configuration of the honeycomb core and vibration and acoustic behavior is important to optimize design of sandwich panels.
In this work, a finite element model is developed in MATLAB to evaluate the …

Oral Delivery Of Peptide Drugs For Mitigation Of Crohn's Disease, Paul Blichmann

All Theses

Protein drugs are typically administered intravenously, but this practice has clear disadvantages such as widespread circulation and swift clearance from the body. Orally delivered protein drugs are not yet available but potentially offer improved distribution, retention, and activity by use of protective matrices and cell-specific targeting. Much work has been done on delayed release formulations for the upper intestine, but there has not been overwhelming evidence of protection of peptides from gastric conditions. In many instances the large intestine may be a better release target due to lower proteolytic activity. Afflictions of the colon such as Inflammatory Bowel Disease and …