Engineering Commons^™

Ac Direct Drive Led Lighting Using Low Cost Analog Components, Miles Head

Master's Theses

This project explores the rapidly expanding area of AC direct drive for LED lighting. AC LED driving does not use typical DC-DC converter-based driving but uses semiconductor switches and a linear regulator to activate a number of LEDs proportional to the input voltage at any given time. This allows bulky, expensive magnetics to be eliminated from the system. The goal of this project was to design a scaled-down physical AC LED direct drive system to validate the conclusions of methods for improving efficiency from a previous investigation that found minimizing voltage across the linear regulating MOSFET led to higher efficiency …

Developing Material Specification And Application Criteria For Sealing Concrete Bridge Decks, Danny Wells, Sudhir Palle, Theodore Hopwood Ii

Kentucky Transportation Center Research Report

The Kentucky Transportation Cabinet (KYTC) has more aggressively pursued preventive maintenance in recent years. Sealing concrete bridge decks is one preventive maintenance activity the Cabinet has actively pursued. KYTC’s Divisions of Maintenance and Structural Design requested assistance from researchers at the Kentucky Transportation Center (KTC) in developing a material specification and application criteria for sealing concrete bridge decks at an appropriate time in their life cycle.

To develop a material specification and application criteria for sealing concrete bridge decks, KTC researchers conducted the following work:

1. Perform a national survey of departments of transportation (DOTs) for guidelines.
2. Perform a literature search …

Design Optimization Of Electric Machines With 3d Fea And A New Hybrid Doe-De Numerical Algorithm, Narges Taran, Vandana Rallabandi, Dan M. Ionel, Greg Heins, Dean Patterson, Ping Zhou

Power and Energy Institute of Kentucky Faculty Publications

This paper discusses the multi-objective optimization of axial flux permanent magnet (AFPM) machines with ferrite spoke-type magnets, utilizing 3D finite element models. Three-dimensional finite element analysis is computationally expensive, and furthermore, substantial computation time is expended by optimization algorithms in evaluating low performing designs whose performance is far from the optimum if the search space is not specified correctly. In this regard, this work proposes two new methods for identifying the search space. The search is limited to ranges of input geometric variables where high performing designs are likely to be found. The optimization algorithm utilized is based on surrogate …

Inductance Testing For Ipm Synchronous Machines According To The New Ieee Std 1812 And Typical Laboratory Practices, Vandana Rallabandi, Narges Taran, Dan M. Ionel, Ping Zhou

Power and Energy Institute of Kentucky Faculty Publications

Equivalent circuit parameters serve as the basis for performance estimation and implementation of power electronic drives controls and therefore their accurate evaluation is very important. Specified in the newly approved IEEE Std 1812, a short-circuit test can be employed, in combination with an open-circuit measurement, in order to determine the back emf and the synchronous inductance. In the case of interior permanent magnet (IPM) machines, this approach can be used only to determine the d-axis inductance and additional and separate measurements are required for the q-axis inductance. In this respect, various methods, inclusive of dc step response tests, on-load tests, …

A Comparative Study Of Methods For Calculating Ac Winding Losses In Permanent Magnet Machines, Narges Taran, Vandana Rallabandi, Dan M. Ionel, Greg Heins, Dean Patterson

Power and Energy Institute of Kentucky Faculty Publications

In this study different methods of estimating the additional ac winding loss due to eddy currents at open-circuit are explored. A comparative study of 2D and 3D FEA, and hybrid numerical and analytical methods is performed in order to recommend feasible approaches to be employed. Axial flux permanent magnet (AFPM) machine case studies are included, namely a machine with open slots and a coreless configuration. These machine topologies are expected to present a substantial amount of ac winding loss, which would therefore need to be considered during optimal design. This study is one of the first ones to compare meticulous …

Design, Fabrication, And Characterization Of Multilayer Hyperbolic Metamaterials, James Dilts

Graduate Theses - Physics and Optical Engineering

Hyperbolic metamaterials (HMMs) show extreme anisotropy, acting as metals and dielectrics along orthogonal directions. They are designed using the effective medium theory (EMT) and can be fabricated using standard semiconductor processing techniques. Current techniques used to characterize the optical behavior of HMMs have a high complexity or are unable to robustly determine the complex permittivity tensor. We describe the details of a procedure to obtain a very low mean-squared-error (MSE) for extraction of permittivity from hyperbolic metamaterials using spectroscopic ellipsometry. We have verified our procedure by fabricating three different samples of various materials and fill factors designed to have a …

Silicon Based Schottky Diodes And Mos Capacitors For Sensing Singly And Multiply Charged Ions With Low Kinetic Energy, Daniel Blaine Cutshall Iii

All Dissertations

This study provides the foundation for the development of radiation detection technology of slow ions by investigating the fundamental interactions of slow ion beams with electronic devices. Silicon samples with a 50 nm oxide layer were irradiated with 1 keV Ar^Q+ beams (Q = 4, 8, and 11) at normal incidence in order to investigate the relatively unexplored effects of slow highly charged ions (HCIs) on electronic devices. After irradiation, an array of metal contacts was deposited onto the oxidized silicon samples to create metal oxide semiconductor (MOS) capacitors, which were then characterized using high frequency capacitance-voltage (C-V) measurements. …

Deep Neural Ranking For Crowdsourced Geopolitical Event Forecasting, Giuseppe Nebbione, Derek Doran, Srikanth Nadella, Brandon Minnery

Computer Science and Engineering Faculty Publications

There are many examples of “wisdom of the crowd” effects in which the large number of participants imparts confidence in the collective judgment of the crowd. But how do we form an aggregated judgment when the size of the crowd is limited? Whose judgments do we include, and whose do we accord the most weight? This paper considers this problem in the context of geopolitical event forecasting, where volunteer analysts are queried to give their expertise, confidence, and predictions about the outcome of an event. We develop a forecast aggregation model that integrates topical information about a question, meta-data about …

Silver-Based Microbial Check Valve For Spacecraft Potable Water Systems, Jennifer Gaines

Chemical Engineering Undergraduate Honors Theses

As human space exploration increases, the development of a more efficient potable water treatment system suited for spacecraft becomes crucial. This Waste-management Education Research Consortium (WERC) challenge was designed to explore the viability of microbial control through the utilization of silver ions as a biocide for possible integration into the Tranquility Node 3 water purification system aboard the International Space Station (ISS). Current systems using iodine risk causing hyperthyroidism from overexposure; however, silver can be safely ingested without this side effect. After researching silver delivery methods including electrochemical ion production, controlled release, or a combination of the two, our team …

Using Green Emitting Ph-Responsive Nanogels To Report Environmental Changes Within Hydrogels: A Nanoprobe For Versatile Sensing, Mingning Zhu, Dongdong Lu, Shanglin Wu, Qing Lian, Wenkai Wang, L. Andrew Lyon, Weiguang Wang, Paulo Bártolo, Brian R. Saunders

Engineering Faculty Articles and Research

Remotely reporting the local environment within hydrogels using inexpensive laboratory techniques has excellent potential to improve our understanding of the nanometer-scale changes that cause macroscopic swelling or deswelling. Whilst photoluminescence (PL) spectroscopy is a popular method for such studies this approach commonly requires bespoke and time-consuming synthesis to attach fluorophores which may leave toxic residues. A promising and more versatile alternative is to use a pre-formed nanogel probe that contains a donor/acceptor pair and then “dope” that into the gel during gel assembly. Here, we introduce green-emitting methacrylic acid-based nanogel probe particles and use them to report the local environment …

The Most Powerful Thing, Caitlin Jankiewicz

Lake Union Herald

No abstract provided.

Restricted Crossing U-Turns At Rural Intersections, Timothy Adams

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

This study examines the potential for replacing the standard intersection design at two-way stop control (TWSC) and all-way stop control (AWSC) intersections along rural highways with a roundabout or a restricted crossing u-turn (RCUT) facility. The geometry of the RCUT design prohibits left and through movements from the side road, and provides a u-turn location downstream from the main crossing. This type of facility has been implemented for rural highways extensively in other states and has the potential to serve as a cost-effective solution to improve roadway safety within Nebraska.

Comparative analysis is conducted for three site locations (Humphrey, Madison, …

Application Of Remote Sensing Technology In Water Resources Management, Mahesh Pun

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

The primary goal of this dissertation was to leverage the capabilities of remote sensing technology for capturing detailed spatial information at different spatial resolutions to monitor agricultural crops and generate accurate input datasets for water resources models. This dissertation is divided into three different research studies. In the first study, a remote sensing classification method was developed for classifying irrigated and non-irrigated fields that integrates Vegetation indices with surface energy balance fluxes. The method was applied in the COHYST2010 hydrological model region with wide climate variation and to multiple growing seasons with results that were 92.1% accurate and explained 97% …

Image Processing Algorithms For Elastin Lamellae Inside Cardiovascular Arteries, Mahmoud Habibnezhad

School of Computing: Dissertations, Theses, and Student Research

Automated image processing methods are greatly needed to replace the tedious, manual histology analysis still performed by many physicians. This thesis focuses on pathological studies that express the essential role of elastin lamella in the resilience and elastic properties of the arterial blood vessels. Due to the stochastic nature of the shape and distribution of the elastin layers, their morphological features appear as the best candidates to develop a mathematical formulation for the resistance behavior of elastic tissues. However, even for trained physicians and their assistants, the current measurement procedures are highly error-prone and prolonged. This thesis successfully integrates such …

Full Scale 13-Story Building Implosion And Collapse: Effects On Adjacent Structures, Kanchan Devkota

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

Two dormitory halls at the University of Nebraska-Lincoln known as Cather and Pound halls were demolished via controlled implosion on December 22, 2017. Cather and Pound halls were two thirteen-story reinforced concrete structures. The demolition of these two structures included the implosion of controlled charges at selected columns on alternating floors which initiated the progressive collapse of these structures. Three nearby structures in the vicinity of Cather and Pound halls were instrumented with high sensitivity uniaxial piezoelectric accelerometers to record the response of the adjacent structures during the event of the implosion and the progressive collapse. While these two thirteen-story …

Device Engineering Of Algan/Gan Hemts For Applications In Power-Electronic And Sensing, Isra Mahaboob

Legacy Theses & Dissertations (2009 - 2024)

The research work presented in this Ph.D. thesis focuses on the engineering of AlGaN/GaN high electron mobility transistors (HEMTs) for the development of future device technology in power electronic and sensing applications.

Design And Cost Analysis Of Acrylic Acid Plant, Adam Ferrier

Chemical Engineering Undergraduate Honors Theses

The purpose of this project was to model and design a plant to produce 75,000 tons per year of acrylic acid. Using the design in section B.9 of Richard Turton’s Analysis, Synthesis, and Design of Chemical Processes as a starting point, a plant was designed based around the partial oxidation of propylene to acrylic acid. The final plant design produces about 86,000 tons per year of acrylic acid. Using an interest rate of 10%, the plant has a discounted cash flow rate of return of 32% over 2 years of startup and 10 years of operation. Attached is an executive …

Efficient Private Information Retrieval, Konstantinos Nikolopoulos

Dissertations, Theses, and Capstone Projects

A vast amount of today's Internet users' on line activities consists of queries to various types of databases. From traditional search engines to modern cloud based services, a person's everyday queries over a period of time on various data sources, will leave a trail visible to the query processor, which can reveal significant and possibly sensitive information about her. Private Information Retrieval (PIR) algorithms can be leveraged for providing perfect privacy to users' queries, though at a restrictive computational cost. In this work, we consider today's highly distributed computing environments, as well as certain secure-hardware devices, for optimizing existing PIR …

A Purely Defeasible Argumentation Framework, Zimi Li

Dissertations, Theses, and Capstone Projects

Argumentation theory is concerned with the way that intelligent agents discuss whether some statement holds. It is a claim-based theory that is widely used in many areas, such as law, linguistics and computer science. In the past few years, formal argumentation frameworks have been heavily studied and applications have been proposed in fields such as natural language processing, the semantic web and multi-agent systems. Studying argumentation provides results which help in developing tools and applications in these areas. Argumentation is interesting as a logic-based approach to deal with inconsistent information. Arguments are constructed using a process like logical inference, with …

Vulnerability Analysis Of Modern Electric Grids: A Mathematical Optimization Approach, Matthew Millis

Industrial Engineering Undergraduate Honors Theses

Electrical power must be transmitted through a vast and complicated network of interconnected grids to arrive at one’s fingertips. The US electric grid network and its components are rapidly advancing and adapting to the advent of smart technologies. Production of electricity is transitioning to sustainable processes derived from renewable energy sources like wind and solar power to decrease dependence on nonrenewable fossil fuels. These newly pervasive natures of smart technology and the variable power supply of renewable energy introduce previously unexamined vulnerabilities into the modern electric grid. Disruption of grid operations is not uncommon, and the effects can be economically …

Seeing Eye To Eye: A Machine Learning Approach To Automated Saccade Analysis, Maigh Attre

Honors Scholar Theses

Abnormal ocular motility is a common manifestation of many underlying pathologies particularly those that are neurological. Dynamics of saccades, when the eye rapidly changes its point of fixation, have been characterized for many neurological disorders including concussions, traumatic brain injuries (TBI), and Parkinson’s disease. However, widespread saccade analysis for diagnostic and research purposes requires the recognition of certain eye movement parameters. Key information such as velocity and duration must be determined from data based on a wide set of patients’ characteristics that may range in eye shapes and iris, hair and skin pigmentation [36]. Previous work on saccade analysis has …

Analysis And Proposed Improvement Of Hamilton County Vw Elab Equipment, Hiroshi Yanagida

Honors Theses

Digital fabrication laboratories have revolutionized project based learning within K-12 STEAM education curriculum. However, classroom utilization of the labs often requires excessive machine hours to accomplish, and this often leads to rapid machine depreciation and disrepair. Many educators do not have the time to repair their equipment while developing curriculum and engaging with their students. This study focuses on building a repair history for common digital fabrication equipment, which includes Prusa i3 Mk2S FDM 3D printers, laser cutters, and CNC routers. Data were collected over a 6 month period to find which machines encountered the most issues. The 3D printers …

Development Of One-Equation Arsm-K-Kl Model And Extension Of Wray-Agarwal Turbulence Model To Transitional And Rough Wall Flows, Tianshu Wen

McKelvey School of Engineering Graduate Student Theses & Dissertations

In last five decades, Computational Fluid Dynamics (CFD) has become a mature technology and the CFD solvers are now regularly employed in the analysis and design of automobiles, aircrafts and a wide variety of other industrial applications. Despite of its wide usage, one of its building blocks, namely the ‘Turbulence Modeling’ still remains a pacing item in accurate computation of fluid flows; turbulence models are required in numerical simulation of turbulent flows using the Reynolds Averaged Navier-Stokes equations (RANS). Even though Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) can provide better accuracy, the needed computing power at present …

Development Of A Multi-Probe Kelvin Scanner Device For Industrially-Relevant Characterization Of Surface-Activated Carbon Fiber Reinforced Thermoplastic Composites, Kirby Simon

McKelvey School of Engineering Graduate Student Theses & Dissertations

Carbon fiber reinforced thermoplastic (CFRTP) composites are becoming increasingly attractive materials in manufacturing due to their lightweight nature, mechanical strength, and corrosion resistance. Surface activation of these materials is usually required during processing to increase the bond strength of assemblies (aerospace and automotive industries) or improve adhesion with implants (biomedical industry). Industrially-relevant, nondestructive quality control methods for assessing the activation state of these materials do not currently exist, however. Applying principles discovered through the use of scanning probe microscopy, a multiple-probe Kelvin scanning (MPKS) device has been developed that can assess the uniformity of the activation state of plasma-treated CFRTP …

Operating Systems Laboratory, Emt 2390l, Course Outline, Jose Reyes Alamo

Open Educational Resources

Students study the characteristics of operating systems used in IBM systems. They learn how to install the operating systems and set it up to control the computer hardware. They also learn to use the features of the operating systems to manage the computer system.

Improving The Order Management System Of A Small Manufacturing Plant, Kelly Mckenna

Graduate Theses - Engineering Management

While many manufacturing companies invest in Enterprise Resource Planning (ERP) software to manage orders and production in their facilities, some companies or facilities may not have the resources, time, or need to implement this software. In such cases, the companies must find efficient ways to track production and orders. The goal of this research was to work with a small manufacturing plant lacking an ERP software to improve their order management system. Improving the system was hypothesized to save the company both time and money by increasing the efficiency of the order management process. The improvements on the previous system …

The Impact Of Inventory Management On The Financial Performance Of U.S. Public Companies, Mohammed G. Ramadan

Graduate Theses - Engineering Management

The U.S. total business inventories were almost 2 trillion U.S. dollars in 2017 which is about 15% of the U.S. gross national product. This implies that there is a great opportunity for U.S. companies to increase their liquidity and the amount of cash available for investment by properly managing their inventory. This research is being conducted to explore the relationship between inventory management and financial performance of the major automotive companies in the U.S. particularly and other public U.S. companies in different industrial sectors.

This research examined the impact and relationship between inventory days, current ratio, debt-to-equity ratio and company’s …

Measuring Effectiveness Of A Virtual Team In The Automotive Workplace, David Alexander Bruce Hopkins

Graduate Theses - Engineering Management

Advanced communication technology is streamlining the way that we create and share data in business practices. The days of paper documentation that is boxed up in a warehouse for dozens of years (due to regulation) are passing. Concurrently, operational teams in the world of business, manufacturing, and engineering are becoming more and more dispersed with international time and space boundaries being dissolved. The reliance on virtual teams to conduct and execute business tasks is growing and the nature of such is changing, possibly affecting team effectiveness. This integrated project explores a team of supplier quality engineers working in the automotive …

Nanoparticle Doped Optical Fibers For High Energy Lasers, Amber L. Vargas

All Theses

Fabrication of rare earth (RE) doped optical fibers for use in fiber-based lasers and amplifiers is conventionally performed using a solution doping technique where RE salts (i.e., ErCl3) are dissolved in a solvent, introduced into the porous silica soot, dried and consolidated to form the active fiber core. This process does not allow for tailoring of the chemical environment about the RE. Alternatively, nanoparticle (NP) doping is more recent approach to incorporating rare earths into an optical fiber and have been shown to permit modification of the chemical environment around the RE in ways the enhance spectroscopic performance. This is …

Smart Home Audio Assistant, Xipeng Wang

All Computer Science and Engineering Research

This report introduces an audio processing algorithm. It provides a way to access smart devices using audio. Although there are many audio assistants already on the market, most of them will not be able to control the smart devices. Therefore, this new system presented in this report will provide a way to analysis the customer’s questions. Then the algorithm will be able to query smart device information, modify the schedule or provide the reason for some arrangement.