Engineering Commons^™

Control Of Energy Density Inside A Disordered Medium By Coupling To Open Or Closed Channels, Raktim Sarma, Alexey Yamilov, Sasha Petrenko, Yaron Bromberg, Hui Cao

Physics Faculty Research & Creative Works

We demonstrate experimentally the efficient control of light intensity distribution inside a random scattering system. The adaptive wave front shaping technique is applied to a silicon waveguide containing scattering nanostructures, and the on-chip coupling scheme enables access to all input spatial modes. By selectively coupling the incident light to the open or closed channels of the disordered system, we not only vary the total energy stored inside the system by a factor of 7.4, but also change the energy density distribution from an exponential decay to a linear decay and to a profile peaked near the center. This work provides …

Infiltration Study Using Tdr Techniques, Saurav Sinha

Civil Engineering Theses - Archive

The study of water flow or infiltration in an unsaturated soil is a highly non-linear and complex problem, simultaneous verification of field and laboratory results is a convenient and practical approach to test the results. In this study, Time domain reflectometry (TDR) sensors are installed at three different locations close to a water body (Creek) in Arlington, Texas which is a part of the National Science Foundation Project titled “Cyper SEES: Type 2: Integrative Sensing and Prediction of Urban Water for Sustainable Cities (iSPUW)”. Time Domain Reflectometry (TDR) and Time Domain Transmissometry (TDT) sensors were deployed at five different depths …

A Decision Support System Tool For Dynamic Pricing Of Managed Lanes, Maryam Zabihi

Civil Engineering Dissertations - Archive

Congestion pricing and managed lanes (ML) have been recently gaining interest around the country as a congestion management tool and as a means of revenue generation for facility maintenance and expansion as well repayment of highway construction debts. Congestion pricing in MLs entails one of several strategies, including time of day pricing, dynamic pricing based on predicted/anticipated traffic conditions, and real-time dynamic pricing based on actual traffic conditions. The overall goal of this study has been to develop a Decision Support System (DSS) tool based on drivers’ revealed willingness to pay (WTP) values. This should determine more effective dynamic toll …

Evaluation Of Structural Capacity Of Epoxy-Coated Concrete Pipes And Its Interaction With Soil, Elmira Riahi

Civil Engineering Dissertations - Archive

Rehabilitation of concrete structures by using synthetic resins such as epoxy is increasing worldwide. Understanding the structural behavior of the resultant composite structure and the interaction between the coating and concrete can be beneficial in predicting performance of the rehabilitated structure. However, very little is known about the strength of the epoxy-coated concrete. This researcher conducted laboratory experiments designed to evaluate epoxy coated concrete specimens under different load configurations with an emphasis on its stress-strain characteristics. The tests include uniaxial compression cylindrical specimens, three-point and four-point bending and tests on beam specimens and three-edge bearing tests on concrete pipe specimens. …

Design Procedures Of Retrofitted Bridge Rail, Richard L. Wood, Yijun Liao, Mohammad E. Mohammadi, Jordan Wipf

Nebraska Department of Transportation: Research Reports

The use of shallow embedment anchors in concrete is essential for retrofit applications; however, the combination of steel anchors, chemical adhesive, and concrete acting as a single tensile mechanism creates uncertainties in anchor strength and failure modes. Differences in concrete compressive strengths and in specifications of adhesives between manufacturers increases uncertainty further. In addition to these issues, prior research conducted by others examines the behavior of such anchors with respect to cracked versus uncracked concrete, partial bonding of the embedded length, and strength reductions due to anchor proximity to edges. While it is understood, anchors require a proper installation detail, …

Identifying And Addressing Soil Property Issues Affecting Roadside Vegetation Establishment, Xu Li, Martha Mamo, Walter H. Schacht, Tala Awada, Humberto Blanco-Canqui

Nebraska Department of Transportation: Research Reports

Attaining adequate vegetation cover along highways is important for NDOR to comply with EPA’s stormwater regulations. However, low plant cover is a common problem on shoulders (first 16 feet off the pavement) of many highways in Nebraska. The ultimate goal of this study is to identify cost-effective engineering solutions that assure adequate seed beds (i.e., soil conditions) for establishment of selected seeding mixtures. The objectives of this study are to (1) characterize the soil properties along roadsides where vegetation stands have not developed well, and (2) verify the effects of select soil property parameters on plant germination and establishment.

Sampling …

Inducing Emotional Response In Interactive Media, Keenan M. Reimer

Master's Theses

Video games, and entertainment media have been developed for many years, and eliciting emotional experiences is an integral part of that process. Producing and editing game content in order to affect desired emotional experiences can be expensive and cumbersome to developers. This paper presents a study intended to show that such experiences can be affected with simple after-the-fact audio-visual effects. As subjects of the study, participants experience three different emotional states, fear, peace, and none, over three rounds and in three different game environments. They are given a simple narrative in each environment that directs them to gather various objects. …

Investigation Of Copling Strength And Directionality Between Eeg And Fnirs At Resting State Using Permutation Conditional Mutual Information, Gowtham Krishnan Murugesan

Bioengineering Theses - Archive

The motivation of study is to combine multimodality approach EEG-fNIRS to study relationship between neural activity and hemodynamic response applying information theory concepts. Investigating human brain function can be improved by employing a multimodal neuroimaging approach. Since each neuroimaging modality has its own characteristic features especially in terms of spatial and temporal resolution integrating fNIRS responses with EEG could accurately characterize the neurovascular coupling in cortical regions selected as part of the brain network involved in motor and cognitive behavior. Simultaneous recording of fNIRS-EEG is therefore an important resource for studying aspects of neurovascular coupling and its relationship with pathological …

Investigating Causal Interactions In The Human Brain Using Eeg And Fnirs, Borzou Alipourfard

Bioengineering Theses - Archive

It is necessary for distributed neural assemblies to work in collaboration to achieve the most elementary brain functions. Activities within segregated neural assemblies are integrated to process an incredibly diverse collection of cognitive tasks. Measures such as correlation, cross-correlation, coherence and phase delay make limited use of the information that is available with the advanced multichannel and multimodal recordings of the brain’s activity. They can also give spurious and false results. Most importantly, these bivariate measures are not capable of describing the interaction among multiple neural assemblies and the effective connectivity among them. Through causality analysis, we can identify these …

Effect Of Severe Corrosion On Lateral Strength Of Square Rc Bridge Columns, Sara Sotoud

Dissertations - ALL

Corrosion of reinforcing steel bars is the primary durability problem that causes degradation of reinforced concrete structures located in aggressive environments. Severe corrosion of steel bars decreases the lateral load-carrying capacity of reinforced concrete members, causes loss in the mechanical properties of reinforcement and cross-sectional area of steel bars and concrete cover, bond deterioration, reduces anchorage of steel bars, and decreases the confinement by transverse reinforcement. Consequently, corrosion results in drop in the lateral strength of columns. Therefore, studying response of corroded reinforced concrete columns subjected to lateral loads is necessary.

According to the Federal Highway Administration (FHWA) report in …

Second Law Of Thermodynamics Analysis Of An Internal Combustion Engine Fueled With Methane, Muataz Abotabik

Masters Theses

The second law of thermodynamics is a powerful tool for calculating the amount of energy that can be converted to work (i.e., the exergy or availability of a system), which cannot be predicted using the first law. The objectives of this research project are to quantify the availability during the compression, combustion and expansion processes of a spark-ignited engine fueled with methane; and to highlight differences in the thermo-mechanical availability of the ideal and spark-ignition (SI) engine cycles. A cooperative single-cylinder research engine was used to measure the data required for availability analysis at equivalence ratios ranging between 0.83 and …

Exploring Dynamic Memory Allocations For Bioinformatics Applications, Nitya Kovur

School of Computing: Dissertations, Theses, and Student Research

The progression of scientific data leads to an increase in the demand of powerful high performance computers (HPC) where data can be stored and analyzed. High performance computing is used in several research areas to solve large problems. However, efficient usage of supercomputing resources that are available is a major concern for most of the researchers. The user has to choose the amount of resources needed for execution before submitting the job. Over or under subscription of resources leads to low system utilization and/or low user satisfaction.

Bioinformatics is one such field that heavily relies on HPC. One of the …

Eventflowslicer: A Goal-Based Test Case Generation Strategy For Graphical User Interfaces, Jonathan Saddler

School of Computing: Dissertations, Theses, and Student Research

Automated test generation techniques for graphical user interfaces include model-based approaches that generate tests from a graph or state machine model of the interface, capture-replay methods that require the user to specify and demonstrate each test case individually, and modeling-language approaches that provide templates for abstract test cases. There has been little work, however, in automated goal-based testing, where the goal is a realistic user task, a function, or an abstract behavior. Recent work in human performance regression testing (HPRT) has shown that there is a need for generating multiple test cases that execute the same user task in different …

Application Of Genetic Algorithm In Multi-Objective Optimization Of An Indeterminate Structure With Discontinuous Space For Support Locations, Rahat Sultana

Masters Theses

In this thesis, an indeterminate structure was developed with multiple competing objectives including the equalization of the load distribution among the supports while maximizing the stability of the structure. Two different coding algorithms named “Continuous Method” and “Discretized Method” were used to solve the optimal support locations using Genetic Algorithms (GAs). In continuous method, a continuous solution space was considered to find optimal support locations. The failure of this method to stick to the acceptable optimal solution led towards the development of the second method. The latter approach divided the solution space into rectangular grids, and GAs acted on the …

Numerical Modeling Of Virus Transport Through Unsaturated Porous Media, Kandala Rajsekhar, Pramod Kumar Sharma, Sanjay K. Shukla

Research outputs 2014 to 2021

This paper describes the movement of virus in one-dimensional unsaturated porous media. The governing virus transport equations consider the inactivation in liquid phase, liquid–solid interface, air–liquid interface, and sorption in both liquid–solid and air–liquid interfaces. Finite-volume method has been used for solving the advection and dispersion processes of the virus transport equation. The effects of transport parameters on virus concentration profiles have been investigated for virus present in liquid phase, adsorbed liquid–solid and liquid–air phases. The results show that the movement of viruses in three phases is affected by soil moisture, inactivation rate, pore velocity, and mass transfer coefficients. It …

Chlorine Demand Shows Thresholds And Hierarchy With Source Water Quality At Beaver Lake, Arkansas, Jaime M. Gile

Graduate Theses and Dissertations

This study investigated the effects of source water quality in Beaver Lake on the amount of chlorine (Cl) needed to develop decision support system to help guide chlorination practices in pre-treatment of source water. Chlorine demand assays were performed on water samples from Beaver Lake collected from the intake structure at Beaver Water District from March 2014 through August 2015, and using data from these assays, the two points of interest in this study were the Cl dose at which Cl residuals began to accumulate and the mean Cl demand occurring after that dose. Three methods of analysis were used …

Design And Analysis Of An Asynchronous Microcontroller, Michael Hinds

Graduate Theses and Dissertations

This dissertation presents the design of the most complex MTNCL circuit to date. A fully functional MTNCL MSP430 microcontroller is designed and benchmarked against an open source synchronous MSP430. The designs are compared in terms of area, active energy, and leakage energy. Techniques to reduce MTNCL pipeline activity and improve MTNCL register file area and power consumption are introduced. The results show the MTNCL design to have superior leakage power characteristics. The area and active energy comparisons highlight the need for better MTNCL logic synthesis techniques.

Asynchronous Data Processing Platforms For Energy Efficiency, Performance, And Scalability, Liang Men

Graduate Theses and Dissertations

The global technology revolution is changing the integrated circuit industry from the one driven by performance to the one driven by energy, scalability and more-balanced design goals. Without clock-related issues, asynchronous circuits enable further design tradeoffs and in operation adaptive adjustments for energy efficiency. This dissertation work presents the design methodology of the asynchronous circuit using NULL Convention Logic (NCL) and multi-threshold CMOS techniques for energy efficiency and throughput optimization in digital signal processing circuits. Parallel homogeneous and heterogeneous platforms implementing adaptive dynamic voltage scaling (DVS) based on the observation of system fullness and workload prediction are developed for balanced …

Channel Estimation Overhead Reduction For Downlink Fdd Massive Mimo Systems, Abderrahmane Mayouche

Graduate Theses and Dissertations

Massive multiple-input multiple-output (MIMO) is the concept of deploying a very large number of antennas at the base stations (BS) of cellular networks. Frequency-division duplexing (FDD) massive MIMO systems in the downlink (DL) suffer significantly from the channel estimation overhead. In this thesis, we propose a minimum mean square error (MMSE)-based channel estimation framework that exploits the spatial correlation between the antennas at the BS to reduce the latter overhead. We investigate how the number of antennas at the BS affects the channel estimation error through analytical and asymptotic analysis. In addition, we derive a lower bound on the spectral …

Modeling Economic Impacts Of The Inland Waterway Transportation System, Furkan Oztanriseven

Graduate Theses and Dissertations

The inland waterway transportation system of the United States (U.S.) handles 11.7 billion tons of freight annually and connects the heartland of the U.S. with the rest of the world by providing a fuel-efficient and environmentally friendly mode of transportation. This dissertation aims to create decision support tools for maritime stakeholders to measure the economic impacts of the inland waterway transportation systems under real world scenarios including disruptions, demand changes, port expansion decisions, and channel deepening investments. Monte Carlo simulation, system dynamics, discrete-event simulation, agent-based modeling, and multiregional input-output modeling techniques are utilized to analyze the complex relationships between inland …

Electrodeionization Versus Electrodialysis: A Clean-Up Of Produced Water In Hydraulic Fracturing, Brigitte Marie Rodgers

Graduate Theses and Dissertations

Electrodeionization (EDI) is a widely studied process ranging from applications in wastewater clean-up in the food and beverage industry to purifying organic compounds. To date, there are no apparent studies on applying this technology to produced wastewater recovered from hydraulic fracking sites. Water consumption within hydraulic fracturing sites can reach in the upwards of millions of gallons per site, so a need for a water recycling process becomes necessary within areas where water requirements are scarce. Implementation of an EDI module that is capable of handling high salt solutions from produced wastewater in subsequent fracturing practices will decrease overall water …

Essays On Optimization And Modeling Methods For Reliability And Reliability Growth, Thomas Paul Talafuse

Graduate Theses and Dissertations

This research proposes novel solution techniques in the realm of reliability and reliability growth. We first consider a redundancy allocation problem to design a system that maximizes the reliability of a complex series-parallel system comprised of components with deterministic reliability. We propose a new meta-heuristic, inspired by the behavior of bats hunting prey, to find component allocation and redundancy levels that provide optimal or near-optimal system reliability levels. Each component alternative has an associated cost and weight and the system is constrained by cost and weight factors. We allow for component mixing within a subsystem, with a pre-defined maximum level …

Robust Bi-Directional Continuous Electrowetting Based On Metal-Semiconductor (M-S) Diodes, Qi Ni, Daniel E. Capecci, Millicent Schlafly, Nathan B. Crane

Faculty Publications

We demonstrate bi-directional continuous electrowetting by embedding metal-semiconductor diodes in the electrowetting substrate. Unlike conventional electrowetting on dielectric (EWOD), bi-directional continuous electrowetting uses a single electrode pair to actuate a droplet through long distances. As long as the voltage potential is maintained between two end electrodes, the droplet moves toward the electrode with the higher potential. However, previously reported material systems had limited success in repeated actuation. In this work, diodes based on Schottky barriers were fabricated by forming metal-semiconductor junctions between titanium and high resistivity n-type silicon. The performance enhancements were evaluated using current-voltage measurements of interface pairs. When …

Determining Energy Output In Manual And Automated Solar Arrays, James K. Ayres

Honors Theses

The scope for the project was to design and construct a system that could be used to both manually and automatically track the sun using solar panels to demonstrate engineering principles for classroom and laboratory experiments at both the primary and secondary education levels. For ease of demonstration, a manual and automatic tracker was designed for the experiment. Using a standard camera tripod, the solar panels were attached to fabricated mounts to allow for omnidirectional movement. For the automated, or active tracker, an Ardunio Uno microcontroller was used in conjunction with two 180˚ servos to adjust the active tracker solar …

Medium Altitude Long Endurance Remotely Piloted Aircraft Training: A Pilot Study In Blended Learning, Zachary P. Waller, Thomas Petros, John Bridewell, Scott Kroeber, Neil Nowatzki

Aviation Faculty Publications

Since April of 2011, research and development efforts between the Air Force Research Laboratory (AFRL) and the University of North Dakota (UND) have progressed through the “Science and Technology for Warfighter Training and Aiding.” Cooperative Agreement. One product of these cooperative efforts has been a Heads Down Display (HDD) Menu Trainer. Designed to familiarize students with the layout and manipulation of the HDD menus for either the MQ-1 or MQ-9, a parallel pretest/posttest design was designed to examine the efficacy of this HDD menu trainer as training aid in traditional, blended, and distance pedagogies.

Results of a mixed ANOVA indicated …

Three-Dimensional Adult Cardiac Extracellular Matrix Promotes Maturation Of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes, Ahsley H. Fong, Mónica Romero-López, Christopher M. Heylman, Mark Keating, David Tran, Agua Sobrino, Anh Q. Tran, Hiep H. Pham, Cristhian Fimbres, Paul D. Gershon, Elliot L. Botvinick, Steven C. George, Christopher C.W. Hughes

Biomedical Engineering

Pluripotent stem cell-derived cardiomyocytes (CMs) have great potential in the development of new therapies for cardiovascular disease. In particular, human induced pluripotent stem cells (iPSCs) may prove especially advantageous due to their pluripotency, their self-renewal potential, and their ability to create patient-specific cell lines. Unfortunately, pluripotent stem cell-derived CMs are immature, with characteristics more closely resembling fetal CMs than adult CMs, and this immaturity has limited their use in drug screening and cell-based therapies. Extracellular matrix (ECM) influences cellular behavior and maturation, as does the geometry of the environment—twodimensional (2D) versus three-dimensional (3D). We therefore tested the hypothesis that native …

Laboratory And Full Boom-Based Investigation Of Nozzle Setup And Restriction Effects On Flow, Pressure And Spray Pattern Distribution, Shane H. Forney

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Pesticide application is an integral part of crop production and ground-based agricultural boom sprayers are used extensively to apply pesticides to the crop canopy or soil surface across millions of acres in the United States. Efficient application is necessary to minimize costs and limit adverse environmental impacts. Errors in flow rate and system pressure measurements may cause as-applied maps to incorrectly indicate application rates and could negatively affect downstream data processing or analysis. The goals of this study were to provide quantified measurements on the effects of nozzle setup errors on spray pattern uniformity and evaluate how laboratory patternator data …

Multi-Sensory Emotion Recognition With Speech And Facial Expression, Qingmei Yao

Dissertations

Emotion plays an important role in human beings’ daily lives. Understanding emotions and recognizing how to react to others’ feelings are fundamental to engaging in successful social interactions. Currently, emotion recognition is not only significant in human beings’ daily lives, but also a hot topic in academic research, as new techniques such as emotion recognition from speech context inspires us as to how emotions are related to the content we are uttering.

The demand and importance of emotion recognition have highly increased in many applications in recent years, such as video games, human computer interaction, cognitive computing, and affective computing. …

The Influence Of The Electric Supply Industry On Economic Growth In Less Developed Countries, Edward Richard Bee

Dissertations

This study measures the impact that electrical outages have on manufacturing production in 135 less developed countries using stochastic frontier analysis and data from World Bank’s Investment Climate surveys. Outages of electricity, for firms with and without backup power sources, are the most frequently cited constraint on manufacturing growth in these surveys.

Outages are shown to reduce output below the production frontier by almost five percent in Africa and by a lower percentage in South Asia, Southeast Asia and the Middle East and North Africa. Production response to outages is quadratic in form. Outages also increase labor cost, reduce exports …

Packing Sheet Materials Into Cylinders And Prisms Using Origami-Based Approaches, Jared Thomas Bruton

Theses and Dissertations

Packing sheet materials into cylinders and prisms using Origami-based approaches (Soft Origami or traditional Origami) is of interest in fields where sheet materials need folded into cylinders or prisms. Fully-dense packing has application in fields where a sheet material is to be folded with minimal gaps into a cylinder or prism. Partially-dense packing is applicable to fields where gaps are required between packed surfaces or where hollow volumes are to be filled, such as in fluid filter design. Soft Origami is explored as a method for folding soft-sheet materials into fully-dense cylinders. Two fold patterns, the "flasher'' and the "inverted-cone …