Engineering Commons^™

Contribution Of Fiber Undulation To Mechanics Of Three-Dimensional Collagen-I Gel, Shengmao Lin, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

The collagen-I gel is extensively used as a scaffold material in tissue engineering due to its ability to mimic the extracellular matrix (ECM). In this study, the mechanics of collagen-I gel is investigated using a numerical model of three-dimensional collagen network. The resulted mechanical behavior was validated against the published experimental data. Results illustrated that fiber alignment was dominated in the low strain region, and its transition to stretching dominated phenomena at higher strain led to the strain stiffening of collagen gel. The collagen undulation at the microscopic level was found to delay the initiation of strain stiffening

Predicting General Aviation Pilots’ Weather-Related Performance Through A Scenario-Based Written Assessment, Jessica Cruit

Doctoral Dissertations and Master's Theses

Weather-related accidents continue to challenge the general aviation community and with the development of advanced weather technology, GA pilots need additional education and training on how to effectively use these weather products to ensure flight safety. Currently, the literature on aviation weather suggests that there is a gap in both training and assessment strategy for GA pilots. Furthermore, several studies suggest that there needs to be more assessment of weather-related scenario/application questions for the private pilot’s written knowledge exam in order to assess a deeper level of knowledge for weather-related material. The purpose of this study is to design a …

The Effects Of Safety Culture And Ethical Leadership On Safety Performance, Kevin O’Leary

Doctoral Dissertations and Master's Theses

This dissertation investigated the effects of safety culture and ethical leadership on safety performance in Fractional jet pilots in the United States. The primary objective was to develop a well-fitted model linking these constructs. A composite survey instrument was developed from instruments previously validated in the literature.

There were 305 complete and valid responses from Fractional pilots. The hypothesized factor structure consisted of seven factors. The exogenous factor of safety culture was made up of four sub-factors. The endogenous factors included ethical leadership, pilot commitment, and safety performance. Safety performance was a second order factor consisting of errors and attitudes …

The Effect Of Generation On Retention Of Women Engineers In Aerospace And Industry, Kristine Maria Kiernan

Doctoral Dissertations and Master's Theses

The purpose of this dissertation was to determine the nature and extent of differences between generational cohorts regarding the effect of family factors on retention of women in engineering, with an emphasis on women in the aerospace industry. While 6% of the aerospace workforce is made up of aeronautical engineers, an additional 11.2% of the aerospace workforce is drawn from other engineering disciplines. Therefore, the analysis included all engineering sub-disciplines. In order to include women who had left the workforce, women in all industries were used as a proxy for women in aerospace.

Exits to other fields were modeled separately …

Development Of An Improved Method For Determining Advisory Speeds On Horizontal Curves, Eric R. Green, Kenneth R. Agent, Erin Lammers-Staats

Kentucky Transportation Center Research Report

Horizontal curves are an integral part of the highway alignment. However, a disproportionately high number of severe crashes occur on them. One method transportation agencies use to reduce the number crashes at horizontal curves is the installation of curve warning signs which post an appropriate advisory speed. Appropriate curve advisory speeds can be determined using several methods. Some of these methods are time-consuming to perform and are error-prone. The purpose of this research was to find the most efficient and accurate data collection method for determining curve advisory speeds. Several processes were developed and tested. They were then validated against …

Fabrication, Characterization And Skin Permeation Of Antoxidant-Loaded Lipid Vesicles For Transdermal Drug Delivery., Emily Martin

Electronic Theses and Dissertations

Excess production of Reactive Oxygen Species (ROS), which can be caused by radiation, cigarette smoke, and pollutants, can cause many damaging cellular effects, such as DNA damage and unregulated cell apoptosis. If left unmitigated, chronic overproduction of ROS has been linked to the formation of cancer, diabetes, atherosclerosis, rheumatoid arthritis, chronic inflammation, Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, and amyotrophic lateral sclerosis. ROS is typically eliminated with antioxidants, which scavenge and inhibit the formation of ROS by becoming oxidized by the ROS and by binding to its precursors.

Curcumin is an effective lipid-soluble antioxidant agent. However, its poor bioavailability, rapid …

Machine Learning Methods For Medical And Biological Image Computing, Rongjian Li

Computer Science Theses & Dissertations

Medical and biological imaging technologies provide valuable visualization information of structure and function for an organ from the level of individual molecules to the whole object. Brain is the most complex organ in body, and it increasingly attracts intense research attentions with the rapid development of medical and bio-logical imaging technologies. A massive amount of high-dimensional brain imaging data being generated makes the design of computational methods for efficient analysis on those images highly demanded. The current study of computational methods using hand-crafted features does not scale with the increasing number of brain images, hindering the pace of scientific discoveries …

Phytovolatilization Of Organic Contaminants, Matt Limmer, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Plants can interact with a variety of organic compounds, and thereby affect the fate and transport of many environmental contaminants. Volatile organic compounds may be volatilized from stems or leaves (direct phytovolatilization) or from soil due to plant root activities (indirect phytovolatilization). Fluxes of contaminants volatilizing from plants are important across scales ranging from local contaminant spills to global fluxes of methane emanating from ecosystems biochemically reducing organic carbon. In this article past studies are reviewed to clearly differentiate between direct- and indirect-phytovolatilization and we discuss the plant physiology driving phytovolatilization in different ecosystems. Current measurement techniques are also described, …

Estimation Of Average Daily Traffic On Local Roads In Kentucky, Reginald R. Souleyrette, Brian K. Howell, Eric R. Green, William Nicholas Staats

Kentucky Transportation Center Research Report

Kentucky Transportation Cabinet (KYTC) officials use annual average daily traffic (AADT) to estimate intersection performance across the state maintained highway system. KYTC currently collects AADTs for state maintained roads but frequently lacks this information on local roads. A method is needed to estimate local road AADTs in a cost-effective and reasonable manner. Kentucky Transportation Center (KTC) researchers conducted a literature review on U.S. AADT models but found that none of them were suitable to Kentucky. Therefore, KTC developed an AADT model using non-linear regression to estimate AADTs on approaches to those intersections.

KTC developed a Poisson distributed, non-linear regression model …

Investigation Of Interfacial Interaction Of Manganese Oxides With Organic Micropollutants, Mohamed Nabil Shaikh

Civil Engineering ETDs

Water reuse has become a necessary practice in arid and semi-arid regions like the Southwestern USA. However, a new generation of emerging organic micropollutants has been increasingly scrutinized in water sources. The aim of this study is to determine the changes in chemical composition occurring on the MnOx(s) surface after reaction with organic micropollutants using X-ray Photoelectron spectroscopy (XPS), Raman spectroscopy and solution chemistry analyses. Laboratory batch experiments were conducted to assess the reactivity of MnOx(s) with aniline, triclosan, phenol and bisphenol A. Analyses of XPS high resolution scans through the determination of the shape and position of Mn 3p …

Investigating Pedestrian Crash Risk In Albuquerque, New Mexico, Rahul Reddy Gade

Civil Engineering ETDs

Walking, being an important and basic form of transportation is crucial in everyday day life. Seen as an alternative to traditional modes of transport, walking is seen as an effective way to reduce dependence on fossil fuels and personal transport. Its health benefits and positive changes to the community are seen as incentives to promote walking as an effective mode of transport. As such, pedestrian safety is of utmost importance given the increase in pedestrian numbers and correspondingly, pedestrian crashes. The thesis studies pedestrian crash data and computes pedestrian crash rates for different intersections in Albuquerque, New Mexico. Crash rates …

Effects Of Alternative Traffic Input Levels On Interstate Pavement Performance In New Mexico, Md Amanul Hasan

Civil Engineering ETDs

Traffic is one of the key inputs in pavement design. The pavement Mechanistic-Empirical (ME) design allows three different types of input level of traffic data based on the availability of the data. They are: site specific data (Level 1), regional data (Level 2), and the national data (Level 3). Level 1 inputs (e.g., load magnitude, configuration, and frequency) are generated from Weigh-in-Motion (WIM) station installed in each site. However, it is not always practically possible to install WIM station due to high cost of WIMs. Therefore, often time the designers have to rely on the Level 2 or Level 3 …

Secure Massive Mimo Transmission With An Active Eavesdropper, Yongpeng Wu, Robert Schober, Derrick Wing Kwan Ng, Chengshan Xiao, Giuseppe Caire

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we investigate secure and reliable transmission strategies for multi-cell multi-user massive multiple-input multiple-output systems with a multi-Antenna active eavesdropper. We consider a time-division duplex system where uplink training is required, and an active eavesdropper can attack the training phase to cause pilot contamination at the transmitter. This forces the precoder used in the subsequent downlink transmission phase to implicitly beamform toward the eavesdropper, thus increasing its received signal power. Assuming matched filter precoding and artificial noise (AN) generation at the transmitter, we derive an asymptotic achievable secrecy rate when the number of transmit antennas approaches infinity. For …

Embedding The Behavior Macromodel Into Tdie For Transient Field-Circuit Simulations, Huan Huan Zhang, Li (Lijun) Jun Jiang, He Ming Yao

Electrical and Computer Engineering Faculty Research & Creative Works

A novel transient field-circuit simulation method based on the time-domain integral equation (TDIE) and circuit macromodels is proposed. The traditional field-circuit simulation process constructs Kirchoff's equations for linear or nonlinear lumped circuits, which cannot handle problems with unknown circuit structure. The proposed method creates parametric behavior macromodels to represent the port constitutive relations of the circuits. Artificial neural network technique is adopted to estimate the model parameters based on the known port voltages and currents. Then, the obtained macromodel is coupled with TDIE that describes the behavior of electromagnetic subsystem to form the equations of a whole system, which can …

Wartime Construction Project Outcomes As A Function Of Contract Type, Ryan M. Hoff, Gregory D. Hammond, Peter P. Feng, Edward D. White

Faculty Publications

The United States has spent more than $23 billion on construction in Afghanistan since 2001. The dynamic security situation created substantial project uncertainty, and many construction projects used cost-plus-fixed-fee contracts (CPFF) instead of the firm-fixed-price (FFP) norm. Using a dataset of 25 wartime construction projects managed by the Air Force Civil Engineer Center, the authors sought to confirm that both contract types yield project outcomes consistent with the established literature. As expected, they found CPFF contracts had greater cost and schedule growth than FFP. However, they did not find differences regarding as-built quality. Additionally, the authors sought to determine whether …

Configuration And Optimization Of A Novel Compressed-Air-Assisted Wind Energy Conversion System, Jie Cheng

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

The increasing concerns over the environmental impact of carbon emissions and the unsustainability of conventional fossil fuel power plants are stimulating interest in the implementation of renewable energy in current power systems. Among all of the renewable energies, wind energy holds a prominent place because of its high output and the maturity of the technology. However, like all of the other renewable energies, integration of wind energy into the power grid causes some quality and control issues, such as overvoltage or undervoltage and frequency excursion.

To mitigate these issues and build a robust wind power system, a novel structure referred …

Measurement Of Thermal Properties And Porosity Of Consolidated Salt., Laxmi Prasad Paneru

Civil Engineering ETDs

Salt formations may be used as repositories for long term isolation of nuclear waste. Excavating drifts in a subsurface salt formation produces granular salt spoils, which could be used as sealing material for boreholes and drifts. In drifts, the backfilled salt would conduct heat from the waste load to the host rock salt. The efficiency of heat dissipated from the backfill will depend on the thermal properties of the backfill. The results of this study show how these thermal properties evolve with the porosity of consolidating granular salt. Thermal properties and porosity of laboratory-consolidated salt and in situ partially consolidated …

Reconstructing The Historical Albuquerque Reach Of The Middle Rio Grande To Evaluate The Influence Of River Engineering On Floodplain Inundation, Jourdan Adair

Civil Engineering ETDs

Sustainable floodplain management is essential in achieving a balance between population growth and natural resource protection, especially in the face of climate change. While floodplain development in the Middle Rio Grande Valley has allowed for economic expansion in the region, it has come at a cost to the fragile ecosystem of the Southwest. In this study, the historical Albuquerque reach of the Middle Rio Grande is reconstructed, including floodplain topography, channel characteristics, and land cover from approximately 1918. The impacts of river engineering on flooding events are evaluated by comparing historic and current conditions. Hydrodynamic modeling is first used to …

Advancing The Food-Energy-Water Nexus: Closing Nutrient Loops In Arid River Corridors, Jacob Mortensen

Civil Engineering ETDs

Closing nutrient loops in terrestrial and aquatic ecosystems is integral to achieve resource security in the food-energy-water (FEW) nexus. Multiyear (2005-08), monthly samples of instream dissolved inorganic nutrient concentrations (NH4-N, NO3-N, soluble reactive phosphorus-SRP) along a ~300-km of the Rio Grande, NM, USA were used to investigate how the net source/sink behavior of wastewater and irrigated agriculture can be holistically managed to close nutrient loops. Wastewater on average contributed over 90% of the instream dissolved inorganic nutrients (101 kg/day NH4-N, 1097 kg/day NO3-N, 656 kg/day SRP). During growing seasons, the irrigation network downstream of wastewater outfalls retained on average 37% …

Thin Film Alsb Carrier Transport Properties And Room Temperature Radiation Response, Erin Vaughan

Nuclear Engineering ETDs

Theoretical predictions for AlSb material properties have not been realized using bulk growth methods. This research was motivated by advances in molecular beam epitaxial (MBE) growth technology to produce high-quality thin-film AlSb for the purpose of evaluating transport properties and suitability for radiation detection. Simulations using MCNP5 were performed to benchmark an existing silicon surface barrier detector and to predict ideal AlSb detector behavior, with the finding that AlSb should have improved detection efficiency due to the larger atomic number of Sb compared with Si. GaSb diodes were fabricated by both homoepitaxial MBE and ion implantation methods in order to …

The Controlled Human Gyroscope, Randy Claude Arjunsingh

Theses and Dissertations

The objective of this thesis was to design an adaptive rotational motion simulator capable of replicating the attitudes of spacecrafts and aircrafts, while avoiding gimbal lock. Flight motion simulators are currently used for flight training and research, but there are many limitations to these existing systems. This thesis presents a low-cost design for a rotational motion platform titled, ‘The Controlled Human Gyroscope’. It uses a 4-axis system instead of the conventional 3-axis system to avoid gimbal lock and prevent the unnecessary motion of the user. The Human Gyroscope features unlimited rotation about the roll, pitch and yaw axes regardless of …

Numerical Modeling Of Soy Biodiesel To Maximize Engine Power And Efficiency While Minimizing Pollutant Emissions, Ehsan Tootoonchi

Theses and Dissertations

Biodiesel is a renewable fuel that can help to reduce dependence on foreign petroleum and to help control the negative environmental effects of combustion engines. This work develops a numerical model for soy biodiesel combustion in diesel engine applications. A comprehensive breakup model for diesel and biodiesel combustion calculations using the KIVA- 3V is presented. The primary breakup model calculates the outcome of the initial breakup stage using flow conditions, nozzle geometry, and liquid fuel characteristics, and assigns the Sauter Mean Radius (SMR) values to injecting droplets. The Kelvin-Helmholtz/Rayleigh-Taylor(KH-RT) model acts as the secondary model to break up injected particles. …

Column-Grid-Array (Cga) Versus Ball-Grid-Array (Bga): Boardlevel Drop Test And The Expected Dynamic Stress In The Solder Material, Ephraim Suhir, Reza Ghaffarian

Mechanical and Materials Engineering Faculty Publications and Presentations

Board level drop test is considered with an objective to develop a physically meaningful analytical predictive model for the evaluation of the expected impactinduced dynamic stresses in the solder material. Ball-gridarray (BGA) and column-grid-array (CGA) designs are addressed. Intuitively it is felt that while the application of the CGA technology to relieve thermal stresses in the solder material might be quite effective (owing to the greater interfacial compliance of the CGA in comparison with the BGA), the situation might be quite different when the PCB/package experiences dynamic loading. This is because the mass of the CGA joints exceeds considerably that …

Pythagorean Combinations For Lego Robot Building., Ronald I. Greenberg

Computer Science: Faculty Publications and Other Works

This paper provides tips for LEGO robot construction involving bracing or gear meshing along a diagonal using standard Botball kits.

Avalanche Isfet Sensing Chip For Dna Sequencing, Mohammad Uzzal

Electrical and Computer Engineering ETDs

DNA sequencing is a fundamental tool for biological science, aimed primarily at uncovering the genetic contributions to diseases. The first Human DNA sequence, which employed conventional fluorescent-based Sanger Sequencing method, took many years to complete at a cost of over three billion dollars. In one survey, it shows that Human Genome Project (HGP) had generated more than $67 billion in U.S. economic output, $20 billion in personal income for Americans and 310 thousand jobs in USA, only during year 2010. The HGP has increased the need for high-throughput, low cost, fast, accurate and inexpensive DNA sequence technique. This demand has …

Probabilistic Anomaly Detection In Natural Gas Time Series Data, Hermine Nathalie Akouemo Kengmo Kenfack, Richard J. Povinelli

Electrical and Computer Engineering Faculty Research and Publications

This paper introduces a probabilistic approach to anomaly detection, specifically in natural gas time series data. In the natural gas field, there are various types of anomalies, each of which is induced by a range of causes and sources. The causes of a set of anomalies are examined and categorized, and a Bayesian maximum likelihood classifier learns the temporal structures of known anomalies. Given previously unseen time series data, the system detects anomalies using a linear regression model with weather inputs, after which the anomalies are tested for false positives and classified using a Bayesian classifier. The method can also …

Optimal Design Of Ipm Motors With Different Cooling Systems And Winding Configurations, Alireza Fatemi, Dan M. Ionel, Nabeel Demerdash, Thomas W. Nehl

Electrical and Computer Engineering Faculty Research and Publications

Performance improvement of permanent magnet (PM) motors through optimization techniques has been widely investigated in the literature. Oftentimes the practice of design optimization leads to derivation/interpretation of optimal scaling rules of PM motors for a particular loading condition. This paper demonstrates how these derivations vary with respect to the machine ampere loading and ferrous core saturation level. A parallel sensitivity analysis using a second-order response surface methodology followed by a large-scale design optimization based on evolutionary algorithms are pursued in order to establish the variation of the relationships between the main design parameters and the performance characteristics with respect to …

Fast Multi-Objective Cmode-Type Optimization Of Pm Machines Using Multicore Desktop Computers, Alireza Fatemi, Dan M. Ionel, Nabeel Demerdash, Thomas W. Nehl

Electrical and Computer Engineering Faculty Research and Publications

Large-scale design optimization of electric machines is oftentimes practiced to achieve a set of objectives, such as the minimization of cost and power loss, under a set of constraints, such as maximum permissible torque ripple. Accordingly, the design optimization of electric machines can be regarded as a constrained optimization problem (COP). Evolutionary algorithms (EAs) used in the design optimization of electric machines including differential evolution (DE), which has received considerable attention during recent years, are unconstrained optimization methods that need additional mechanisms to handle COPs. In this paper, a new optimization algorithm that features combined multi-objective optimization with differential evolution …

Cascading Failures In Interdependent Infrastructures: An Interdependent Markov-Chain Approach, Mahshid Rahnamay-Naeini, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

Many critical infrastructures are interdependent networks in which the behavior of one network impacts those of the others. Despite the fact that interdependencies are essential for the operation of critical infrastructures, such interdependencies can negatively affect the reliability and fuel the cascade of failures within and across the networks. In this paper, a novel interdependent Markov-chain framework is proposed that enables capturing interdependencies between two critical infrastructures with the ultimate goal of predicting their resilience to cascading failures and characterizing the effects of interdependencies on system reliability. The framework is sufficiently general to model cascading failures in any interdependent networks; …

Predictive Coupled-Cluster Isomer Orderings For Some SiNCM (M, N ≤ 12) Clusters: A Pragmatic Comparison Between Dft And Complete Basis Limit Coupled-Cluster Benchmarks, Jason N. Byrd, Jesse J. Lutz, Duminda S. Ranasinghe, Yifan Jin, Ajith Perera, Xiaofeng F. Duan, Larry W. Burggraf, John A. Montgomery Jr.

Faculty Publications

The accurate determination of the preferred Si₁₂C₁₂ isomer is important to guide experimental efforts directed towards synthesizing SiC nano-wires and related polymer structures which are anticipated to be highly efficient exciton materials for opto-electronic devices. In order to definitively identify preferred isomeric structures for silicon carbon nano-clusters, highly accurate geometries, energies and harmonic zero point energies have been computed using coupled-cluster theory with systematic extrapolation to the complete basis limit for set of silicon carbon clusters ranging in size from SiC₃ to Si₁₂C₁₂. It is found that post-MBPT(2) correlation energy plays a …