Engineering Commons^™

Preventive Maintenance Decision Modeling In Health And Service Systems, Mahboubeh Madadi

Graduate Theses and Dissertations

This dissertation focuses on the preventive maintenance decision modeling in healthcare and service systems. In the first part of this dissertation, some issues in preventive health decisions for breast cancer are addressed, and in the second part, the required characteristics for preventive maintenance of an unreliable queuing system are derived.

Adherence to cancer screening is the first issue that is addressed in this dissertation. Women’s adherence or compliance with mammography screening remained low in the recent years. In this dissertation, we first develop a design-based logistic regression model to quantify the probability of adherence to screening schedules based on women’s …

Noncontact Diffuse Optical Assessment Of Blood Flow Changes In Head And Neck Free Tissue Transfer Flaps, Chong Huang, Yu Lin, Yu Shang, Guoqiang Yu, Jeffrey Radabaugh, Rony Aouad, Thomas J. Gal, Amit B. Patel, Joseph Valentino

Biomedical Engineering Faculty Publications

Knowledge of tissue blood flow (BF) changes after free tissue transfer may enable surgeons to predict the failure of flap thrombosis at an early stage. This study used our recently developed noncontact diffuse correlation spectroscopy to monitor dynamic BF changes in free flaps without getting in contact with the targeted tissue. Eight free flaps were elevated in patients with head and neck cancer; one of the flaps failed. Multiple BF measurements probing the transferred tissue were performed during and post the surgical operation. Postoperative BF values were normalized to the intraoperative baselines (assigning “1”) for the calculation of relative BF …

Airborne Infection In Healthcare Environments: Implications To Hospital Corridor Design, Ehsan Mousavi

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Several studies have linked nosocomial transmission airborne diseases to airflow in healthcare settings. Quasi-experimental methods are developed to observe the aerodynamic transport behavior of synthetic respiratory particles in corridors of a hospital. Computational models, validated by experimental results, are then developed to explore the spatial relationships of supply-exhaust air ventilation in patient corridors. The aim of this study is to determine optimal HVAC design strategies to contain and remove airborne contaminants in healthcare environments.

In addition to occupant comfort, hospital HVAC systems are designed to provide ventilation and directional airflow to contain, dilute and remove contaminants including airborne disease. Of …

A Resistive Boundary Condition Enhanced Dgtd Scheme For The Transient Analysis Of Graphene, Ping Li, Li (Lijun) Jun Jiang, Hakan Baʇci

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the electromagnetic (EM) features of graphene are characterized by a discontinuous Galerkin time-domain (DGTD) algorithm with a resistive boundary condition (RBC). The atomically thick graphene is equivalently modeled using an RBC by regarding the graphene as an infinitesimally thin conductive sheet. To incorporate RBC into the DGTD analysis, the surface conductivity of the graphene composed of contributions from both intraband and interband terms is first approximated by rational basis functions using the fast-relaxation vector-fitting (FRVF) method in the Laplace domain. Next, through the inverse Laplace transform, the corresponding time-domain matrix equations in integral can be obtained. Finally, …

Impacts Of Large-Scale Stormwater Green Infrastructure Implementation And Climate Variability On Receiving Water Response In The Salt Lake City Area, Chris York, Erfan Goharian, Steven J. Burian

Faculty Publications

This study evaluated impacts of Green Infrastructure (GI) as a stormwater management practice on return flows and the further Implications of climate variability. The goal was to create a model to explore the impacts that bioretention and Rainwater Harvesting (RWH) representing GI had using goldsim and Stormwater Management Modeling (SWMM) software. The software was used to represent impacts that climate variability individually and combined, may have on downstream stakeholders and receiving water systems in Salt Lake city, Utah, USA. Primary stakeholders included downstream water rights users, Farmington Bay waterfowl management area and the migratory birds that rely on Farmington Bay …

Jsish, Ryan Grasell

Computer Science and Software Engineering

For my senior project, I implemented Professor Keen’s JSish spec in C++. JSish is a subset of Javascript with support for execution from the command line and files.

I chose this project because I wanted to reinforce my programing language skills, learn C++, and gain a deeper understanding of garbage collection.

I quickly grew familiar with C++. My prior experience with both C and Java was a good enough introduction to let me hit the ground running. The biggest hurdle for me was the lack of garbage collection built into C++. I understood the principles of manual memory management, but …

Development And Uses Of Iterative Systematic Literature Reviews In Electrical Engineering Education, Branimir Pejcinovic

Electrical and Computer Engineering Faculty Publications and Presentations

It is expected that most, if not all, graduate students will posses skills necessary for doing literature reviews. It is less clear how to teach these skills most effectively especially to students who are area novices and unfamiliar with review process. Systematic literature reviews offer a solid instructional framework which can be implemented across curriculum and offer an opportunity to teach course material differently so that student learn not just the literature review technique itself but also some segment of the course material. Our pilot study investigated issues related to practical implementation of systematic literature reviews in two classes, with …

Omnidirectional Circularly Polarized Antennas – A Small Antenna Perspective, Adam Narbudowicz, Max Ammann

Articles

The paper discusses recent developments and challenges in the design of small omnidirectional
circularly-polarized (CP) antennas. Although omnidirectional CP coverage is easily achievable using antenna arrays, it is just recently that small and low-cost antennas delivered this functionality.
The paper addresses practical design problems for these antennas, not reported in previous publications.
This includes selection of the omnidirectional plane relative to the ground plane and measurement challenges. Future perspectives on how these antennas can provide electronically steerable beams are investigated using simulated results.

Renewable Energy In Industrial Applications, Seshi Reddy Kasu

Dissertations, Theses and Capstone Projects (Full IR Collection)

Manufacturing industry accounts for about one third of total energy use worldwide. Roughly three quarters of industrial energy use is related to the production of energy-intensive commodities such as ferrous and non-ferrous metals, chemicals and petrochemicals, non-metallic mineral materials, and pulp and paper. In these sectors, energy costs constitute a large proportion of total production costs, so managers pay particular attention to driving them down. As a result, the scope to improve energy efficiency tends to be less in these most energy intensive sectors than in those sectors where energy costs form a smaller proportion of total costs, such as …

Wirelessly Connected Sensor Acquisition System For Remote Nursing Applications, Yuhua Hu

Dissertations, Theses and Capstone Projects (Full IR Collection)

Taking advantage of the equipment used in the "Remote Nursing" project, nurses can watch patients' status remotely. The equipment, which is installed in the patient's ward or home, can monitor them and their environment. This project demonstrates this using a microcontroller system that interfaces to a video camera and temperature and humidity sensors in the room. Also a servomotor is installed to control the position of the camera. The microcontroller communicates wirelessly with a PC.

This project is focused on hardware rather than software. It is to test the video camera and sensors being used over the microcontroller through the …

Peroxidase Inhibition Assay For The Detection Of Some Thiols By Carbon Screen Printed Electrodes Based On Square Wave Voltammetry, Wischada Jongmevasna, Orawon Chailapakul, Manchumas Hengsakul Prousoontorn

Journal of Metals, Materials and Minerals

Cassava peroxidase (CSP) from leaves of cultivar KU50 was used as an alternative peroxidase for the electrochemical detection of thiram and thiourea.Square-wave voltammetry (SWV) incorporated with screen-printed carbon electrode was applied for the investigation of peroxidase activity. It was based on the measurement of 3, 3-diaminobenzidine (DAB) electro active product catalyzed by CSP and horseradish peroxidase (HRP) in 0.04 M Britton-Robinson buffer, pH 6, containing urea hydrogen peroxide in 96-well microplate. The reaction mixture in the presence of either thiourea or thiram was performed in order to study their effects on DAB oxidation catalyzed by both peroxidases. From the result …

Room Acoustic Effects On Speech Comprehension Of English-As-Second-Language Talkers And Listeners Versus Native-English-Speaking Talkers And Listeners, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

Approximately 21% of the children in the United States school system speak a language other than English at home, but are being taught in English at school. English is additionally being used more and more often as a common language in international settings, even though participants at these international events again are not native English speakers. How do adverse room acoustic environments, including higher background noise levels and longer reverberation times, impact English-as-a-Second-Language (ESL) talkers and listeners versus native English-speaking talkers and listeners? This presentation focuses on two recent studies at the University of Nebraska that investigate how assorted room …

Prediction -- The Quintessential Policy Model Validation Test, Wayne Wakeland

Complex Systems Faculty Publications and Presentations

It is essential to objectively test how well policy models predict real world behavior. The method used to support this assertion involves the review of three SD policy models emphasizing the degree to which the model was able to fit the historical outcome data and how well model-predicted outcomes matched real world outcomes as they unfolded. Findings indicate that while historical model agreement is a favorable indication of model validity, the act of making predictions without knowing the actual data, and comparing these predictions to actual data, can reveal model weaknesses that might be overlooked when all of the available …

Lateral Resistance Of Pipe Piles Near 20-Ft Tall Mse Abutment Wall With Strip Reinforcements, Jason James Besendorfer

Student Works

Full scale lateral load testing was performed on four 12.75x0.375 pipe piles spaced at 3.9, 2.9, 2.8, and 1.7 pile diameters behind an MSE wall which was constructed for this research to determine appropriate reduction factors for lateral pile resistance based on pile spacing behind the back face of the wall. The load induced on eight soil reinforcements located at various transverse distances from the pile and at different depths was monitored to determine the relationship between lateral load on the pile and load induced in the reinforcement. Each pile was loaded towards the wall in 0.25 in. increments to …

Design, Fabrication, And Measurement Of A Multiple-Input Multiple-Output (Mimo) Antenna For Mobile Communication, Christopher Charles Arnold

Graduate Theses and Dissertations

This thesis presents the design, fabrication and characterization of a multiband uniplanar MIMO antenna for hand-held mobile communication devices on LTE, WLAN, and WMAN networks. The antenna design methodology combined a variety of broadbanding techniques that resulted in a single-layer hybrid monopole antenna coupled to a meander line element and parasitic structures. The 115×55×1.54 mm antenna was fabricated using an FR4 composite material and occupies only a fractional volume within the size of an average cellular phone allowing ample space to integrate with existing hardware. Characterization of the MIMO antenna included input impedance, scattering parameters and radiation pattern cross sections …

Reducing Multiple Access Interference In Broadband Multi-User Wireless Networks, Ali Nayef Alqatawneh

Graduate Theses and Dissertations

This dissertation is devoted to developing multiple access interference (MAI) reduction techniques for multi-carrier multi-user wireless communication networks.

In multi-carrier code division multiple access (MC-CDMA) systems, a full multipath diversity can be achieved by transmitting one symbol over multiple orthogonal subcarriers by means of spreading codes. However, in frequency selective fading channels, orthogonality among users can be destroyed leading to MAI. MAI represents the main obstacle to support large number of users in multi-user wireless systems. Consequently, MAI reduction becomes a main challenge when designing multi-carrier multi-user wireless networks. In this dissertation, first, we study MC-CDMA systems with different existing …

A Computational Study Of The Potential For Lng Tanker Polystyrene Foam Insulation Failure Under Fire Exposure, Jeffrey David Martinez

Graduate Theses and Dissertations

Liquefied natural gas is shipped across the oceans in large marine carriers. The carriers house the LNG using several different insulation systems. One of these systems involves large aluminum spheres insulated with polystyrene foam. Polystyrene foam is very susceptible to heat degradation. This raised issues as to the extent of possible insulation failure caused by a large ship fire. Experiments were done investigating the nature of polystyrene’s thermal degradation, notably by Brauman, Chen, and Matzinger and Butler. A large scale investigation was also performed by Sandia National Laboratory. However, computational modeling of the degradation was lacking. This work set out …

Adaptive Controller Using Runtime Partial Hardware Reconfiguration For Unmanned Aerial Vehicles (Uavs), Nikhil Thomas

Graduate Theses and Dissertations

The goal of this thesis is to explore the feasibility of a multirotor controller system which can dynamically change the arm configuration of a multirotor. Currently most of the multirotor systems have to be powered down, rewired, and programmed with new firmware, to configure how many arms/motors they use to fly. The focus of our effort is to develop a Field Programmable Gate Array (FPGA) based hardware/software controller which uses dynamic partial hardware reconfiguration to switch the arm/motor configuration of a multirotor during operation. We believe that this will make a multirotor more fault tolerant and adaptive. This thesis explains …

Peptoid-Based Klvff Mimics: A Unique Approach To Alzheimer's Disease, James Phillip Turner

Graduate Theses and Dissertations

Alzheimer’s disease (AD) is the leading form of dementia worldwide. AD patients experience a slow, gradual cognitive decline that includes loss of memory and behavioral stability as the disease progresses. Surprisingly, AD is the sixth leading cause of death in the United States and has had a profound impact on the U.S. economy. Though there are medications to help improve the quality of life of diagnosed patients for a period of time, there is still no cure for AD. AD is characterized by the build-up of amyloid plaques that develop from the aggregation of the amyloid beta protein (Aβ) in …

Capillary Electrophoresis For Analysis Of Aβ1-42 Adsorption And Photo-Crosslinking, Jennifer Lynn Kurtz

Graduate Theses and Dissertations

The accumulation of amyloid-beta (Aβ) oligomers is believed to be the driving force behind Alzheimer’s disease (AD) pathogenesis. Due to the metastable nature of Aβ oligomers, the knowledge of Aβ aggregation and accumulation is not well understood. Here, we use capillary electrophoresis (CE) and photo-induced crosslinking of unmodified proteins (PICUP) to learn about the aggregation of Aβ.

First, we explore the effect of capillary coating on Aβ1-42 protein loss using CE. The dynamic coatings tested were PHEA and 50 kDa, 2000 kDa, 5000 kDa, and 8000 kDa PEO. The covalent coating tested was PVA. The results indicated that 2000 kDa …

An Empirical Water Quality And Best Management Practice Prioritization Model For Select Arkansas Watersheds, James Mccarty

Graduate Theses and Dissertations

The purpose of this study was to prioritize subwatersheds using water quality data and watershed characteristics. Water quality data was provided through studies by the Arkansas Natural Resources Commission, Beaver Water District, Arkansas Water Resources Center, and publicly available USGS gage data. A total of 114 sites across five HUC-8 watersheds were analyzed, including 12 USGS gages. Watershed characteristic data was retrieved from USGS and Arkansas GeoStore geodatabase repositories. A significant linear relationship between baseflow and stormflow nutrient concentrations was established allowing for the use of baseflow concentrations in the prioritization methodology. Pearson correlation, linear regression, classification and regression tree, …

Investigating The Impact Of Cryogenic Carbon Capture On Power Plant Performance, Seyed M. Safdarnejad, L. Kennington, Larry Lin Baxter, John Hedengren

Faculty Publications

Cryogenic Carbon Capture (CCC) is a CO2 mitigation process that can be integrated into existing baseline and load following fossil-fueled power plants. This process consumes less energy than conventional chemical absorption and includes energy storage capability. The CCC process has a fast response time to load changes to allow higher utilization of intermittent renewable power sources to be used at a grid-scale level in the power sector. The impact of the CCC process on the performance and operating profit of a single fossil-fueled power generation unit is studied in this paper. The proposed system (power production from wind, coal, and …

Synergy-Based Two-Level Optimization For Predicting Knee Contact Forces During Walking, Gil Serrancolí, Allison Kinney, Josep M. Font-Llagunes, Benjamin J. Fregly

Mechanical and Aerospace Engineering Faculty Publications

Musculoskeletal models and optimization methods are combined to calculate muscle forces. Some model parameters cannot be experimentally measured due to the invasiveness, such as the muscle moment arms or the muscle and tendon lengths. Moreover, other parameters used in the optimization, such as the muscle synergy components, can be also unknown. The estimation of all these parameters needs to be validated to obtain physiologically consistent results. In this study, a two-step optimization problem was formulated to predict both muscle and knee contact forces of a subject wearing an instrumented knee prosthesis. In the outer level, muscle parameters were calibrated, whereas …

Development Of A Muscle Model Parameter Calibration Method Via Passive Muscle Force Minimization, Allison Kinney, Benjamin J. Fregly

Mechanical and Aerospace Engineering Faculty Publications

Computational predictions of subject-specific muscle and knee joint contact forces during walking may improve individual rehabilitation treatment design. Such predictions depend directly on specified model parameter values. However, model parameters are difficult to measure non-invasively. Methods for muscle model parameter calibration have been developed previously. However, it is currently unknown how the musculoskeletal system chooses muscle model parameter values. Previous studies have hypothesized that muscles avoid injury during walking by generating little passive force and operating in the ascending region of the force-length curve. This hypothesis suggests that muscle model parameter values may be selected by the body to minimize …

Wing Tip Vortices From An Exergy-Based Perspective, Muhammad Omar Memon, Kevin Wabick, Aaron Altman, Rainer M. Buffo

Mechanical and Aerospace Engineering Faculty Publications

The lens of exergy is used to investigate a wingtip vortex in the near wake over a range of angles of attack. Exergy is the measure of thermodynamically “available” energy as determined through the more discriminating second law of thermodynamics. Experiments were conducted in a water tunnel at Institute of Aerospace Systems at Aachen.

The data were taken three chord lengths downstream in the Trefftz plane of an aspect ratio 5 Clark-Y wing with a square-edged wing tip using particle image velocimetry. Intuitively, the minimum available energy state is expected to correspond to the maximum lift-to-drag ratio angle of attack. …

Bio-Fuel Alternatives In South African Airways (Saa) Operations - Is It An Effective Response To Vulnerability Over Carbon Taxes And Penalty?, Daniel Kwasi Adjekum

Aviation Faculty Publications

The paper did a comparative analysis of the carbon emission and European Union Emission Trading Surcharges (EU ETS) of South African Airways (SAA) current fleet that used aviation jet A1 fuel and the same fleet if it had used a 25% bio-fuel ‘drop in’ for the European routes within the first quarter of the 2014 flying year (FY 14). Operational data in terms of the flight scheduled, aircraft type, total time enroute, route stage length, passenger estimates were obtained through SAA’s flight operations website. An independent t–test was conducted to compare means of the emissions. The mean carbon dioxide …

Folded Meander Line Antenna For Wireless M-Bus In The Vhf And Uhf Bands, Abraham Loutridis, Matthias John, Max Ammann

Articles

The first dual-band printed monopole antenna for Wireless M-Bus and M2M applications with operation in the VHF and lower UHF band is presented. The antenna operates at 169 MHz and 433 MHz. The miniaturisation of the proposed compact antenna is based on a double-sided meandering structure offering an easily controlled large frequency-ratio. The antenna provides high total efficiency and gain in both bands. Measured and simulated results are reported.

Addressing Uncertainty In Ensemble Sea-Level Rise Predictions, Matthew A. Thomas, Ting Lin

Civil and Environmental Engineering Faculty Research and Publications

Sea-level rise represents a looming hazard to coastal communities which remains difficult to quantify. Ensemble climate change predictions incorporate epistemic uncertainty in the climate modeling process and climate forcing scenarios help portray a range of radiative forcing changes. This study proposes a method for incorporating both model and scenario uncertainty in ensemble projections of thermosteric sea-level rise. A Markov Chain Monte Carlo algorithm is utilized to weigh the contributions of eight process-based climate models as well as the four Representative Concentration Pathways based on convergence criteria and observational data. Hazard analysis and deaggregation combine these contributions over a range of …

The Doomsday Equation And 50 Years Beyond: New Perspectives On The Human-Water System, Anthony J. Parolari, Gabriel Katul, Amilcare Porporato

Civil and Environmental Engineering Faculty Research and Publications

In 1960, von Foerster et al. humorously predicted an abrupt transition in human population growth to occur in the mid‐21st century. Their so‐called ‘Doomsday’ emerged from either progressive degradation of a finite resource or faster‐than‐exponential growth of an increasingly resource‐use efficient population, though what constitutes this resource was not made explicit. At present, few dispute the claim that water is the most fundamental resource to sustainable human population growth. Multiple lines of evidence demonstrate that the global water system exhibits nontrivial dynamics linked to similar patterns in population growth. Projections of the global water system range from a finite carrying …

Reply To “Perception Of Lower Extremity Loading In Stroke”, Virginia W. Chu, T. George Hornby, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

No abstract provided.