Engineering Commons^™

Characterizing Performance Of A Pem Fuel Cell For A Cmet Balloon, Denise A. Mckahn, Whitney Mcmackin

Engineering: Faculty Publications

We present the design of a multi-cell, low temperature PEM fuel cell for controlled meteorological balloons. Critical system design parameters that distinguish this application are the lack of reactant humidification and cooling due to the low power production, high required power mass-density and relatively short flight durations. The cell is supplied with a pressure regulated and dead ended anode, and flow controlled cathode at variable air stoichiometry. The cell is not heated and allowed to operate with unregulated temperature. Our prototype cell was capable of achieving power densities of 43 mW/cm2/cell or 5.4 mW/g. The cell polarization performance of large …

Analyzing Of Tort Claims And Lawsuits Against South Carolina Department Of Transportation Through Classification And Regression Tree Analysis, Sara Familian

All Dissertations

After losing sovereign immunity in 1985, SCDOT employees now focus a significant amount of time in processing tort claims and lawsuits filed against the agency. This is an important issue for transportation agencies considering the fact that money spent defending tort claims and lawsuits, is no longer available for safety and mobility improvements on the state highway system.
The South Carolina Department of Transportation (SCDOT) processes approximately one thousand claims per year and is engaged in nearly one hundred lawsuits per year. SCDOT has paid just over a half million ($523,607) to settle on 1007 claims - approximately 1/3 of …

Application Of Threshold Concepts To Improve A Design-Focused Course In Transportation Engineering, Dan Cernusca, Ghulam Bham

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Design is an integral part of engineering courses. to address its associated problems, however, is a challenging task in instruction because of design's open-endedness and complexity. in this study, two theoretical models were implemented in an introductory transportation engineering course to address the challenges associated with design of a highway. First, the theoretical framework proposed by the threshold concepts model was used to identify a candidate concept for the instructional redesign process. Two major characteristics of threshold concepts, integrativity and transformativity, were used to identify horizontal alignment as a candidate concept for the highway design process. Second, concept mapping was …

Software Framework For Protection Relay Testing, Jason Caleb Johnston

Masters Theses and Doctoral Dissertations

A software application is presented in this thesis that was designed to provide the framework for comprehensive automated testing of power system protection relays. This application was implemented using a model protection system that was designed to simulate actual relaying operations performed in the electric power system. The implemented application provided automated testing functionality that performed phase instantaneous over-current protection and phase distance protection testing. The modularity of the implemented software application provides the framework for the automated testing of a relay’s complete protection abilities. Automated testing using this application was performed by driving the outputs of an Omicron CMC …

Evaluation Of Pre-Consolidation Stress Determination Methods, Omar Conte, Stephanie Rust, Louis Ge, Richard Wesley Stephenson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Pre-Consolidation Pressure Provides Valuable Information About Soil Behavior And, Specifically, Settlement under an Induced Load. Soil is Expected to Have Less Settlement Before its Pre-Consolidation Pressure and Much More Settlement after that Point. the Pre-Consolidation Pressure and the Compressibility of the Soil Can Be Determined from the Results of a One-Dimensional Consolidation Test. Different Methods Have Been Developed to Obtain the Accurate Pre-Consolidation Pressure from One Dimensional Consolidation Test Data. This Paper Presents and Discusses the Results of the One-Dimensional Consolidation Test Data from an Extensive Testing Program. the Test Specimens Used Were Obtained from Multiple Borehole Locations and Were …

Life Cycle Costing Template (Excel), Dermot Kehily

Reports

No abstract provided.

Evaluation Of Long-Term Pavement Marking Performance, Eric R. Green, Kenneth R. Agent

Kentucky Transportation Center Research Report

The objective of the investigation was to evaluate the useful life of pavement markings. The Manual on Uniform Traffic Control Devices (MUTCD) provides general guidelines for the application and installation of pavement markings. However, performance requirements for various types of pavement markings are not included. Retroreflectivity data were collected throughout Kentucky on various longitudinal pavement markings using mobile and manual techniques. Data were collected on one-year, two-year and three-year-old lines. The retroreflectivity levels were analyzed and the several recommendations were made. Minimum levels of retroreflectivity should be set for determining what roads to restripe annually. These values should be lower …

Fiscal Year 2011 Fhwa-536 Report For The Kentucky Transportation Cabinet, Steven Douglas Kreis, Candice Y. Wallace, Bryan Gibson, Sarah M. Mccormack

Kentucky Transportation Center Research Report

The Federal Highway Administration (FHWA) requires state transportation agencies to submit a biennial report on local highway finances. The purpose of these reports is to provide FHWA with the data it needs to capture the financing of highway activities at the local level. Based on this information, it can identify trends in revenue, expenditures, investments, and program development, and in turn make decisions about future investments. The report, FHWA-536, asks agencies to report on four areas of local highway finance: 1) disposition of highway-user revenues; 2) revenues used for roads and streets identified by source and funding type; 3) road …

Anisotropic Thermal Property Measurement Of Carbon-Fiber/Epoxy Composite Materials, Tian Tian

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This work originated from a need for understanding heat transfer in carbon-fiber/epoxy natural-gas tanks undergoing rapid heating during refilling. The dissertation is focused on the determination of the anisotropic thermal properties of carbon-fiber/epoxy composite materials for in-plane and through-thickness directions. An effective anisotropic parameter estimation system consisting of the 3ω experimental technique and an anisotropic two-dimensional heat transfer model is developed.

In the present work, the 3ω method, an experimental technique that has been well established to evaluate the thermal properties of isotropic materials, especially thin film materials, is extended to treat the thermal properties of bulk anisotropic …

Water Quality Models For Stormwater Runoff In Two Lincoln, Nebraska Urban Watersheds, Jake Fisher

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Water quality monitoring was conducted in two urban watersheds (Colonial Hills and Taylor Park) located in southeast Lincoln, NE over a three year period spanning from October 2008 through September 2011. In-line probes continuously measured for turbidity, conductivity, dissolved oxygen, and water temperature while other water quality constituents were analyzed for discrete water samples collected using grab and automatic sampling techniques. The water quality data was used to calculate event mean concentrations (EMCs) for sixteen storm events sampled over the duration of the project period. Three types of stormwater quality multiple linear regression models were developed for the estimation of …

Optical And Magnetic Properties Of Feni Slanted Columnar Thin Films Infiltrated With Pmma And Fe3O4 Nanoparticles, Dan Liang

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

In this thesis, dielectric polymer and magnetic nanoparticles were utilized to hybridize FeNi Slanted columnar thin films (SCTFs). Firstly Fe₃O₄ in PMMA matrix was prepared by physical blending process. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to investigate the dispersion of the nanoparticles in PMMA matrix and the preparation conditions were varied to optimize the dispersion. The hybridized materials were prepared by the infiltration of PMMA and 5 wt% Fe₃O₄ nanoparticles/PMMA to the voids of FeNi SCTFs. Spin-coating and annealing process were employed to reach an excellent infiltration.

The structural …

Relational Neighborhood Inverse Consistency For Constraint Satisfaction: A Structure-Based Approach For Adjusting Consistency And Managing Propagation, Robert J. Woodward

School of Computing: Dissertations, Theses, and Student Research

Freuder and Elfe [1996] introduced Neighborhood Inverse Consistency (NIC) as a local consistency property defined on the values in the variables' domains of a Constraint Satisfaction Problem (CSP). Debruyne and Bessiere [2011] showed that enforcing NIC on binary CSPs is ineffective on sparse graph and too costly on dense graphs. In this thesis, we propose Relational Neighborhood Inverse Consistency (RNIC), an extension of NIC defined as a local consistency property on the tuples of the relations of a CSP. We characterize RNIC for both binary and non-binary CSPs, and propose an algorithm for enforcing it whose complexity is bounded by …

Water Quality Monitoring Of An Urban Stream For Total Maximum Daily Load Assessment, Jeffrey K. Mihulka

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The purpose of this research project was to assess the water quality of an urban stream for total maximum daily load assessment in Omaha, Nebraska. This was accomplished by sampling the water quality at four different sites. These sites included sampling upstream, within, and downstream of the city. These samples were conducted throughout 2010 and 2011.

The results showed that concentrations of Escherichia coli (E. coli) are routinely above established criteria for the state of Nebraska. Concentrations of E. coli that exist in the Papillion Creek Watershed upstream of the City of Omaha have also been shown to be above …

Design, Analysis, And Testing Of In Vivo Surgical Robots, Tyler David Wortman

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Advances in technology have shaped the history of surgical procedures. Recent developments have allowed surgical procedures to become less invasive than traditional open procedures. The transition to Minimally Invasive Surgery (MIS) has resulted in decreased recovery times, improved cosmetic results, and reduced costs. For these reasons, there is interest in further reducing the invasiveness of surgical procedures by accessing the abdominal cavity through a single incision, such as with Laparoendoscopic Single-Site (LESS) surgery. Added complexities, such as unintuitive controls and limited dexterity, prevent the widespread adoption of LESS for complex surgical procedures. Multi-functional in vivo surgical robots have been designed …

Hydraulic Conductivity Of Environmentally Controlled Landfill Liner Test Pad, Camila Maldonado Soria Galvarro

Civil Engineering Undergraduate Honors Theses

Laboratory and field hydraulic conductivity tests have been conducted on soil samples to develop and verify the zone of acceptance for liner placement. Compaction testing and flexible wall hydraulic conductivity tests were performed on fifteen (15) samples to determine the dry unit weight, molding water content, and laboratory permeability. Five of the fifteen samples were compacted at Standard proctor energy, five were compacted at 75 percent of Standard proctor energy, and five were compacted at 50 percent of Standard proctor energy. The results obtained from the laboratory portion of the testing program (the zone of acceptance) are presented. A ten …

Closed-Loop Attitude Control Using Fluid Dynamic Vectoring On An Aerospike Nozzle, Nathan Erni

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Attitude control of a prototype satellite bus using fluid mechanical vectoring on an aerospike nozzle is demonstrated. The design achieves thrust vectoring by injecting propellant asymmetrically into the unconstrained aerospike exhaust plume near the nozzle base. The prototype system uses cold-gas thrusters to both spin-up and de-tumble the test article. The system is configured with axially directed annular flows that produce large longitudinal thrusts and smaller secondary lateral-injection flows for side thrusts. Both open and closed-loop attitude control, with and without main aerospike annular flow active, are demonstrated. Proportional, integral, derivative (PID) regulation is used for closed-loop attitude control. When …

Nanoparticle Necklace Network Arrays Exhibiting Room Temperature Single-Electron Switching, Jennifer L. Kane

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

A single nanoparticle is one of the most sensitive electronic devices for sensing chemicals in a gas or liquid. The conductivity of a single Au nanoparticle is significantly modulated by the binding of a molecule that alters charge by just one electron. However, the single-electron sensitivity requires cryogenic temperatures and interconnection is not easy. A patterned two-dimensional network of one-dimensional nanoparticle necklaces made up of 10 nm Au particles are fabricated and shown to exhibit similar single-electron effect at room temperature. Furthermore, the long range conductivity of over 10’s of microns makes the structure easy to self-assemble onto conventional microelectronics …

Strength Of Polycrystalline Ceramics Under Shock Compression, Jianbin Zhu

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Determinations of Some polycrystalline ceramics’ strength properties and inelastic deformation mechanisms in the shocked state are critically important to the design and optimization of armor structures involving these materials. In this work, multiscale modeling and simulations have been carried out to study strength of the effects of polycrystalline microstructure, crystal anisotropy, porosity, and their interactions with microscopic deformation/damage mechanisms on the responses of several polycrystalline ceramics under shock compression and to extract their shock strengths from the wave profiles measured in the related plate impact shock wave experiments.

With a mesoscopic computational model, the roles of intragranular microplasticity and deformation …

Alternative Crankshaft Mechanisms And Kinetic Energy Recovery Systems For Improved Fuel Economy Of Light Duty Vehicles, Alberto Boretti, Houshsng Masudi, Joseph Scalzo

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The introduction of advanced internal combustion engine mechanisms and powertrains may improve the fuel conversion efficiency of an engine and thus reduce the amount of energy needed to power the vehicle. the paper presents a novel design of a variable compression ratio advanced spark ignition engine that also permits an expansion ratio that may differ from the induction stroke therefore generating an Atkinson cycle effect. the stroke ratio and the ratio of maximum to minimum in-cylinder volumes may change with load and speed to provide the best fuel conversion efficiency. the variable ratio of maximum to minimum in-cylinder volumes also …

Understanding Svocs, Ying Xu, Jianshun Zhang

Mechanical and Aerospace Engineering - All Scholarship

Semi-volatile organic compounds (SVOCs) are an important class of indoor pollutants that are of great health concern. However, they have not received much attention within the ASHRAE community. This column provides an overview of the sources, sinks, transport mechanisms, and potential health effects, and discusses how HVAC systems may affect occupants’ exposure to SVOCs.

Dynamic Botanical Filtration System For Indoor Air Purification, Zhiqiang Wang

Mechanical and Aerospace Engineering - Dissertations

A dynamic botanical air filtration (DBAF) system was developed, tested and modeled for indoor air purification. The DBAF system consisted of an activated-carbon/hydroculture-based root bed for potted-plant, a fan for driving air through the root bed for purification, and an irrigation system for maintaining proper moisture content in the root bed. Results from test conducted in a full-scale open office space indicated that the filtration system had ability to supply clean air equivalent to 80% of required outdoor air supply for the space. The DBAF was effective for removing both formaldehyde and toluene at 5 to 32% volumetric water content …

Optimized Built-In Self-Test Technique For Caen-Based Nanofabric Systems, Sambhav Kundaikar, Maciej Zawodniok

Electrical and Computer Engineering Faculty Research & Creative Works

We propose a built-in self-test (BIST) technique for testing and diagnosis of molecular electronic based nano fabrics. the nano fabric architectures are reconfigurable in nature thus making it possible to utilize general methods similar to those employed for testing of FPGAs. However, a high defect rate in nano fabrics renders the traditional techniques ill-suited. Moreover, the nano blocks offer potential for using a partially damaged nano block due to inherent redundancy of the architecture. This paper presents the design and analysis of testing configurations and optimization scheme that minimizes testing time while improving the utilization of the nano fabric. the …

Contingency Constrained Economic Dispatch In Smart Grids With Correlated Demands, Yiyu Shi, Jinjun Xiong

Electrical and Computer Engineering Faculty Research & Creative Works

Contingency constrained economic dispatch has been an extensively studied research topic. However, most existing works assume that the load demands at all buses are given. Such an assumption works well for conventional power grids, where the load demands are relatively easy to predict. We can select a few representative demand profiles and perform economic dispatch over them. However, such a practice will no longer work in smart grids, where the load demands fluctuate dramatically. We will need a huge number of demand profiles to cover all possible scenarios, which is computationally expensive. to address the problem, we propose a parameterized …

Soft-Decision Feedback Turbo Equalization For Multilevel Modulations, Huang Lou, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

Error propagation phenomena is the major drawback for existing hard-decision feedback turbo equalizers. in this paper, we propose a new soft-decision feedback equalizer (SDFE) suitable for multilevel modulation systems employing turbo equalization. the proposed SDFE offers a low computational complexity growing only linearly with the number of equalizer coefficients, as opposed to the quadratic complexity of MMSE-Based linear turbo equalizer with time-varying coefficients (Exact-MMSE-LE). the performance and convergence property of the proposed SDFE are analyzed using extrinsic information transfer (EXIT) chart and verified by simulations in a severe InterSymbol interference channel set by Proakis. Results show that our approach performs …

3d Image Reconstruction From Sparse Measurement Of Wideband Millimeter Wave Sar Experiments, Hamed Kajbaf, Joseph T. Case, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

Nonuniform random sampling is applied to a wideband 3D synthetic aperture radar (SAR) imaging system to reduce the number of measurement points in both frequency and space domains. Experimental tests were performed on a construction foam specimen using uniformly sampled Q-band frequencies in 35.04 GHz to 44.96 GHz and at a grid of two-millimeter step sizes. using discrete Fourier transform (DFT) or discrete cosine transform (DCT) sparse representations, the 3D images can be reconstructed from 7% random samples of the experimental data achieving comparable quality as the one from original full-set data. This can translate to significant time reduction of …

Mahalanobis-Taguchi System As A Multi-Sensor Based Decision Making Prognostics Tool For Centrifugal Pump Failures, Ahmet Soylemezoglu, Sarangapani Jagannathan, Can Saygin

Electrical and Computer Engineering Faculty Research & Creative Works

A novel Mahalanobis Taguchi System (MTS) based fault detection, isolation, and prognostics scheme is presented. the proposed scheme fuses data from multiple sensors into a single system level performance metric using Mahalanobis Distance (MD) and generates fault clusters based on MD values. MD thresholds derived from the clustering analysis are used for fault detection and isolation. When a fault is detected, the prognostics scheme, which monitors the progression of the MD values over time, is initiated. Then, using a linear approximation, time to failure is estimated. the performance of the scheme has been validated via experiments performed on a mono-block …

Work In Progress - Exercises In Squeak Smalltalk For Pre-College Education, Steve Eugene Watkins, Nicolette Kowalewski, Kathryn N. Rodhouse, Benjamin Cooper

Electrical and Computer Engineering Faculty Research & Creative Works

Computer programming education helps to prepare pre-college students to function in a technology-based society and to promote technical careers. However, opportunities are limited for pre-college students to learn computer programming and effective programming instruction can be difficult. A set of introductory, self-paced tutorials in Squeak Smalltalk has been developed for students in high school and middle school. This work describes two supplementary exercises that address the needs of new learners, especially those at younger ages. Students are given tools for drawing and image manipulation. The optional exercises integrate basic concepts while allowing more interactivity and customization through creative "play." © …

The Development Of A Far Red To Near Infrared Fluorescent Probe For Use In Optical Imaging, Margaret Fiedler

All Theses

New techniques for biological optical imaging are of great interest for the detection and visualization of processes and disease in both clinical and research areas. One major advancement has been the use of far red and near infrared (NIR) light, as it has the ability to penetrate tissues deeper than other parts of the spectrum which are readily scatter and absorbed by the surroundings. In order to improve the signal to noise ratio and resolution of optical images, contrast agents are used. Fluorescent markers can be modified to attach to specific molecular targets, creating small molecular probes. These targets can …

Wireless Solar-Powered Thermal Imaging Camera, Andy Bonk, Billy Mcvicker, Jacob Richardson

Mechanical Engineering

Creation of a mounted wireless self-powered thermal imaging camera system.

Robotic Turret, Daniel Romero, Matthew (Matt) Martelle, Scott Mullens, Rachel Diamant

Mechanical Engineering

No abstract provided.