Engineering Commons^™

A Novel Methodology For Spatial Damage Detection And Imaging Using A Distributed Carbon Nanotube-Based Composite Sensor Combined With Electrical Impedance Tomography, Hongbo Dai, Gerard J. Gallo, Thomas Schumacher, Erik T. Thostenson

Civil and Environmental Engineering Faculty Publications and Presentations

This paper describes a novel non-destructive evaluation methodology for imaging of damage in composite materials using the electrical impedance tomography (EIT) technique applied to a distributed carbon nanotube-based sensor. The sensor consists of a nonwoven aramid fabric, which was first coated with nanotubes using a solution casting approach and then infused with epoxy resin through the vacuum assisted resin transfer molding technique. Finally, this composite sensor is cured to become a mechanically-robust, electromechanically-sensitive, and highly customizable distributed two-dimensional sensor which can be adhered to virtually any substrate. By assuming that damage on the sensor directly affects its conductivity, a difference …

Liberty's Last Post Office: A Story Of A Gold Mining Camp In Washington State, Wesley C. Engstrom

Works by Local Authors

There was once a large center of activity in the Swauk Basin of upper Kittitas County. The place is called Liberty. Liberty was once the most action packed place in Kittitas County. At least it was for a while after gold was discovered in Swauk Creek. Like many gold camps the place boomed and ebbed over the years. Unlike some other places it never quite went completely bust. It came close, and fortunately for some it didn’t. It still exists today as a living ghost town.

The Liberty story has been told before in various ways. This telling of the …

Understanding Millennial, Generation X, And Baby Boomer Preferred Leadership Characteristics: Informing Today’S Leaders And Followers, Lee-Volker Cox

Dissertations

Purpose. This quantitative study’s purpose was to describe and determine the degree of difference and importance of leadership characteristics as perceived by Baby Boom, Generation X, and Millennial generational cohort followers in STEM-related U.S.-based or headquartered aerospace and computer organizations as measured by the Multigenerational Leadership Characteristics Questionnaire (MLCQ).

Methodology. This was a cross-sectional, nonexperimental, comparative and correlational quantitative, ex post facto study. A web-based MLCQ was developed after conducting an academic literature review. Participants used a 6-point Likert scale identifying the importance of 30 characteristics with 2 aggregation questions identifying the most and least important characteristics; 408 members of …

Student From Reu Project Wins Presentation At Emerging Researchers National Conference | Engineering Education, Usu College Of Engineering

College of Engineering News

A student from last year’s REU project, Bethany Fronhofer, attended the 2016 Emerging Researchers National (ERN) Conference. Where she spoke about the work that she did along with Sarah Schott in Dr. Idalis Villanueva’s lab. Bethany’s presentation won first place for the Science and Mathematics Education/Social and Behavioral Sciences Undergraduate Oral Presentation category.

A Review Of Advances In The Identification And Characterization Of Groundwater Dependent Ecosystems Using Geospatial Technologies, Isabel C. Pérez Hoyos, Nir Y. Krakauer, Reza Khanbilvardi, Roy A. Armstrong

Publications and Research

Groundwater Dependent Ecosystem (GDE) protection is increasingly being recognized as essential for the sustainable management and allocation of water resources. GDE services are crucial for human well-being and for a variety of flora and fauna. However, the conservation of GDEs is only possible if knowledge about their location and extent is available. Several studies have focused on the identification of GDEs at specific locations using ground-based measurements. However, recent progress in remote sensing technologies and their integration with Geographic Information Systems (GIS) has provided alternative ways to map GDEs at a much larger spatial extent. This paper presents a review …

In-Situ Testing Of Uretek's Injectable BarrierSm As A Mechanism For Groundwater Control, Jeremy Hess

USF Tampa Graduate Theses and Dissertations

Construction projects involving the installation or repair of subsurface structures or utilities often require dewatering to induce a temporary lowering of the local groundwater elevation to facilitate construction. In the event that a known contaminant plume is present in an adjacent area, this dewatering may inadvertently draw the contaminant into the previously uncontaminated work area. Uretek Holdings, Inc. has developed its Injectable Barrier^SM to be installed prior to dewatering exercises to provide a groundwater cut-off by reducing the potential movement of groundwater due to the hydraulic gradient induced by dewatering. A benefit of Injectable Barrier^SM as compared to …

Adoption Of The Sawyer Water Filter In Peru, Stephanie D. Paredes

USF Tampa Graduate Theses and Dissertations

In Peru, lack of water, sanitation, and hygiene (WASH) results in 6,600 deaths per year that represents approximately 3.9% of total deaths. Three thousand and nine hundred of these deaths were due to diarrheal diseases (Prüss-Üstün et al., 2008). Systematic reviews suggest that interventions to improve microbial quality of drinking water are successful in reducing diarrheal diseases (Fewtrell et al., 2005; Clasen et al., 2007; Fry et al., 2013). Interventions for household water treatment and safe storage to ensure safe drinking water reduce diarrhea by 31-52% (WHO/UNICEF, 2013).

The SAWYER PointONE filter, a portable and adaptable membrane filtration device as …

Conversations About Diversity: Institutional Barriers For Underrepresented Engineering Students, Leroy Long Iii, Joel Alejandro Mejia

Publications

The United States is becoming increasingly more diverse. Specifically, demographics are shifting because of growth among historically underrepresented racial and ethnic minorities, including African Americans, Latinos, and Native Americans. At the same time, a declining number of skilled workers in science, technology, engineering, and mathematics (STEM) fields threatens U.S. global competitiveness and national security. Low participation, representation, engagement, and inclusion continue to reduce the intellectual capacity of the U.S. STEM workforce. The aforementioned societal changes require diversity in STEM education and the nation at large. Past research offers additional support for the importance of diversity. For example, racial diversity can …

Sizing An Anaerobic Digester In A Rural Developing World Community: Does Household Fuel Demand Match Greenhouse Gas Production?, Ronald Keelan Greenwade

USF Tampa Graduate Theses and Dissertations

Anaerobic digestion is the process by which organic carbon is converted into biogas in the form of carbon dioxide (CO₂) and methane (CH₄). Both of these products are greenhouse gases that contribute to global warming. Therefore if anaerobic reactors are improperly maintained and biogas is leaked or intentionally released into the atmosphere because biogas production exceeds household demand, these reactors may become generators of greenhouse gas emissions instead of sustainable energy producers. The objective of this research was to develop a framework to assess if the demand for biogas by a rural adopter of an anaerobic …

Application Of Spatial And Descriptive Analysis Methods To Determine Relationship Between Hardware Subsidies And The Sanitation Marketplace, Danielle Devuyst

USF Tampa Graduate Theses and Dissertations

Sanitation marketing is an emerging approach of strengthening the local private sector to implement scalable and sustainable improved sanitation coverage in developing countries, specifically among the poor. It encourages the enhancement of sanitation market supply and demand by developing distribution infrastructure and stimulating consumer interest. Unlike interventions that provide hardware subsidies to initiate sanitation demand, financial support for sanitation marketing is used exclusively for the research and development of the market; this encourages the private sector to become independent and self-sufficient. Qualitative data suggests that while sanitation marketing projects have been successful at implementing replicable and sustainable sanitation coverage, they …

Early Acidification Of Mars And The Potential Implications For Biology, Sarah Stewart Johnson, D. Goerlitz, Kathleen C. Benison, Melanie R. Mormile, D. W. Ming

Biological Sciences Faculty Research & Creative Works

A leading paleoclimate theory for Mars, based on the identification of phyllosilicate minerals in ancient terrains, posits that the first several million years of the planet’s history were dominated by neutral to alkaline pH. However, evidence is mounting for the consideration of an alternate hypothesis: that some smectites on Mars formed under acidic conditions, and that the early surface of Mars may not have been subject to circum-neutral pH conditions, at least not uniformly. Work on shergottitic liquids suggests that up to 2400 ppm of sulfur could have degassed from martian magma, supplying more than enough sulfur for the planet’s …

Optimizing Forecasting Methods For Ustranscom Railcar Demands, James M. Park

Theses and Dissertations

The United States military heavily relies on rail freight operations to meet many of its logistical needs during both peacetime and wartime efforts. As the head organization responsible for managing and overseeing all modes of military transportation, United States Transportation Command depends on timely accurate railcar demand forecasts to drive critical decisions on distribution and placement of railcar assets. However, the intermittent nature of railcar demands based on location and commodity make it a challenging task for forecasters. Furthermore, these “lumpy” demands often come without any obvious trends or seasonality. This study explores the utility of both traditional forecasting methods …

Cable-To-Post Attachments For Use In Non-Proprietary High-Tension Cable Median Barrier – Phase Ii, Scott K. Rosenbaugh, Robert W. Bielenberg, Jessica L. Lingenfelter, Ronald K. Faller, John D. Reid, Karla A. Lechtenberg

Nebraska Department of Transportation: Research Reports

The objective of this study was to reevaluate and improve the existing cable-to-post attachment hardware that is utilized in the non-proprietary cable barrier being developed at MwRSF. The study focused on redesigning the bolted, tabbed bracket (V10) to eliminate the bolt, reduce the number of components per bracket, eliminate the need for tools during installation, and reduce the number of small parts. Three attachment concepts were selected for evaluation through dynamic testing: (1) the key plate attachment; (2) the wire lock pin attachment; and (3) the pinned back attachment. Each attachment prototype was subjected to two vertical and two lateral …

Modulation Of Whole Cell Currents In Human Neuroblastoma Cells Via The Hormone Aldosterone: An In Vitro Study, Harish Kumar Chittam

USF Tampa Graduate Theses and Dissertations

Ion channels play a critical role in maintaining homeostasis by moving various ions in and out of cells. The Na⁺-K⁺-2Cl^- or NKCC1 ion channel is involved in the regulation of Na⁺, K⁺, and Cl^- across cell membranes, and plays a key role in many forms of cellular physiology. In the cochlea, NKCC1 is involved in endolymph production and maintenance of the endocochlear potential. Our hypothesis is that blocking NKCC1 channels should directly impact auditory sensitivity causing hearing loss. Our lab has also shown that the hormone aldosterone (ALD) can upregulate …

Conversion Of Landfill Gas To Liquid Hydrocarbon Fuels: Design And Feasibility Study, Ryan Alexander Kent

USF Tampa Graduate Theses and Dissertations

This paper will discuss the conversion of gas produced from biomass into liquid fuel through the combination of naturally occurring processes, which occur in landfills and anaerobic digesters, and a gas-to-liquids (GTL) facility. Landfills and anaerobic digesters produce gases (LFG) that can be converted into syngas via a Tri-reforming process and then synthesized into man-made hydrocarbon mixtures using Fischer-Tropsch synthesis. Further processing allows for the separation into liquid hydrocarbon fuels such as diesel and gasoline, as well as other middle distillate fuels. Conversion of landfill gas into liquid fuels increases their energy density, ease of storage, and open market potential …

Hydrogen Effects On X80 Steel Mechanical Properties Measured By Tensile And Impact Testing, Xuan Li

USF Tampa Graduate Theses and Dissertations

The effect of hydrogen charging current density and tensile strain rate on the mechanical properties of X80 pipeline steel were investigated by slow strain rate test (SSRT), Charpy impact test, and scanning electron microscopy (SEM) in this thesis. The results show that both the ultimate tensile strength and elongation to failure of X80 steel were deteriorated significantly after charging with hydrogen. With a strain rate of 5 x 10^-5 s^-1, the relative tensile strength and plasticity loss of X80 steel had no significant change within the range of assumed hydrogen partial pressures at room temperature. At room …

Ray-Based Statistical Propagation Modeling For Indoor Corridor Scenarios At 15 Ghz, Qi Wang, Bo Ai, David W. Matolak, Ruisi He, Xin Zhou

Faculty Publications

According to the demands for fifth-generation (5G) communication systems, high frequency bands (above 6 GHz) need to be adopted to provide additional spectrum. This paper investigates the characteristics of indoor corridor channels at 15 GHz. Channel measurements with a vector network analyzer in two corridors were conducted. Based on a ray-optical approach, a deterministic channel model covering both antenna and propagation characteristic is presented. The channel model is evaluated by comparing simulated results of received power and root mean square delay spread with the corresponding measurements. By removing the impact of directional antennas from the transmitter and receiver, a path …

Electromagnetic Characterization Of Materials Using A Dual Chambered High Temperature Waveguide, Jeffrey S. Sovern

Theses and Dissertations

Measurement of the electromagnetic properties of materials at high temperatures is important for industrial, scientific, medical, and aerospace applications [1]. Current high-temperature electromagnetic material characterization is a time consuming process that typically requires three days to collect data from one material specimen. For example, the standard high-temperature process involving rectangular waveguides [2] requires measurements of the sample (1), the empty waveguide (2), and a metal short standard (3) completed in separate heated runs over three days to perform the Nicolson-Ross-Weir inversion algorithm for computing permittivity and permeability. The technique developed here will reduce the high-temperature measurement process from three days …

Neutron Radiation Effects On Ge And Gesn Semiconductors, Christopher T. O'Daniel

Theses and Dissertations

Two different semiconductor materials received neutron radiation for assessment of radiation damage. The two materials are undoped bulk Ge and epitaxial Ge_0.991Sn_0.009, which is doped heavily with phosphorous. At room temperature, the Ge sample has direct and indirect bandgaps at 0.78 eV and 0.66 eV, respectively. The Ge_0.991Sn_0.009 sample has direct and indirect bandgaps at 0.72 eV and 0.63 eV, respectively. Two samples of each material were exposed to research reactor neutrons, delivering a 1 MeV equivalent neutron fluence of 2.52 × 10¹⁵ n/cm². In order to assess the radiation …

Enhancing Virtual Team Dynamics, Freddie L. Stephens Ii

Theses and Dissertations

With the activation of the Air Force Civil Engineer Center in 2012, the United States Air Force initiated an effort to centralize installation and mission support management throughout the Air Force, while decentralizing the execution at the base level. The measurement of success for such a decision extends beyond the reduction of overhead costs. The goal was to build a responsive, mission-focused organization. This research evaluated specific factors associated with the characteristics of virtual team dynamics to improve the perceived responsiveness of a centralized organization. Leader-member exchange (LMX) theory is a relationship-based approach to leadership that focuses on the quality …

The Effect Of Ph And Pulsed Ultraviolet Light Emitting Diode Duty Cycles On The First Order Rate Constant And Byproduct Profile Of The Advanced Oxidation Of Tartrazine, Brandon M. Stewart

Theses and Dissertations

Water treatment capability is required for military operations, production of drinking water, and industrial wastewater treatment. The Advanced Oxidation Process (AOP) is one of many viable steps for treating water; however, it is important to understand the byproducts of the treatment process to avoid creating other constituents more severe than the first. Tartrazine (TAR) was oxidized with pulsed Ultra- Violet (UV) Light Emitting Diodes (LEDs) in combination with hydrogen peroxide (H2O2) in an AOP at the laboratory scale. The relative concentration of TAR was reduced from 1 to between 1 – 0.75 over pH values between 6 and 9, and …

Mission Dependency Index Of Air Force Built Infrastructure: Knowledge Discovery With Machine Learning, Clark W. Smith

Theses and Dissertations

Mission Dependency Index (MDI) is a metric developed to capture the relative criticality of infrastructure assets with respect to organizational missions. The USAF adapted the MDI metric from the United States Navy’s MDI methodology. Unlike the Navy’s MDI data collection process, the USAF adaptation of the MDI metric employs generic facility category codes (CATCODEs) to assign MDI values. This practice introduces uncertainty into the MDI assignment process with respect to specific missions and specific infrastructure assets. The uncertainty associated with USAF MDI values necessitated the MDI adjudication process. The MDI adjudication process provides a mechanism for installation civil engineer personnel …

Improving System Design Through The Integration Of Human Systems And Systems Engineering Models, Michael E. Watson

Theses and Dissertations

The human is a critical aspect of many systems, but frequently there is a failure to properly account for human capabilities and involvement during system design. This inattention results in systems with higher lifecycle costs, decreased user compatibility, and the potential to produce disastrous consequences. This research presents an approach to integrating the human into system models by using two methods: static and dynamic modeling. The static method uses a user-centered design framework to create system- and human-centered models that deconstruct the system and user into their respective components. These models are integrated to create system models that include relevant …

Design And Analysis Of A Retroreflective Array For Ir Application, Michael E. Bollinger

Theses and Dissertations

This research investigates the adaptation of a Van Atta style of retrodirective array designed to work at 2 GHz to work in the infrared spectrum of 8-12 μm centered at 30 THz. The Computational Research and Engineering Acquisition Tools and Environments (CREATE) software suite and high performance computing (HPC) resources of the HPC Modernization program were utilized to model and simulate multiple steps of an adaptation process to illustrate and examine the incremental performance changes of frequency scaling the design. Two different substrate materials, germanium and hafnium oxide, are evaluated as the dielectric materials, and a comparison of the broadband …

Exposing Inter-Virtual Machine Networking Traffic To External Applications, Charles E. Byrd

Theses and Dissertations

Virtualization is a powerful and fast growing technology that is widely accepted throughout the computing industry. The Department of Defense has moved its focus to virtualization and looks to take advantage of virtualized hardware, software, and networks. Virtual environments provide many benefits but create both administrative and security challenges. The challenge of monitoring virtual networks is having visibility of inter-virtual machine (VM) traffic that is passed within a single virtual host. This thesis attempts to gain visibility and evaluate performance of inter-VM traffic in a virtual environment. Separate virtual networks are produced using VMWare ESXi and Citrix XenServer platforms. The …

Characterization For The Development Of The Hybrid Multi-Junction Silicon Germanium Solar Cell, Jimmy J. Lohrman

Theses and Dissertations

Based on the previous development of the hybrid multi-junction silicon (HMJ-Si) solar cell, this work characterized the preceding design for the development of the hybrid multi-junction silicon germanium (HMJ-SiGe) solar cell. Seven focus areas were investigated: diffraction pattern generation, photon propagation, silicon diffusion processing, ohmic contacts, the distributed Bragg reflector (DBR), the Fresnel zone plate (FZP), and the germanium/germanium telluride (Ge/GeTe) pn-junction Diffraction patterns were theoretically examined, and contact grating design characterization for reflectance and transmittance properties was modeled using rigorous coupled wave analysis. An improved silicon diffusion process follower was developed, and theoretical study and experimental assessment were accomplished …

Tunable Terahertz Metamaterials With Germanium Telluride Components, Christopher H. Kodama

Theses and Dissertations

Terahertz (THz) technology is an emerging field with many exciting applications. THz waves can be used to locate explosives and illicit drugs in security applications, or DNA and other molecule resonances in medical applications. THz frequencies represent the next level of modern, high-speed computing, but they also can be used for covert battlefield communications links. Metamaterials are an integral part of THz technology because they can be used to create exotic material properties—permittivities and permeabilities—in a part of the frequency spectrum that is otherwise rather empty and passive. This work aims to acquire a fuller understanding of THz metamaterials in …

Jamming Cognitive Radios, Travis J. Freeman

Theses and Dissertations

The goal of this thesis is to identify and evaluate weaknesses in the rendezvous process for Cognitive Radio Networks (CRNs) in the presence of a Cognitive Jammer (CJ). Jamming strategies are suggested and tested for effectiveness. Methods for safe- guarding the Cognitive Radios (CRs) against a CJ are also explored. A simulation is constructed to set up a scenario of two CRs interacting with a CJ. Analysis of the simulation is conducted primarily at the waveform level. A hardware setup is constructed to analyze the system in the physical layer, verify the interactions from the simulation, and test in a …

Superconducting Quantum Interference Device Array Based High Frequency Direction Finding On An Airborne Platform, Tyrel K. Kvasager

Theses and Dissertations

This thesis evaluates a new incredibly sensitive highly linear high dynamic range 2D Bi-SQUID array purposed by the dissertation written by Susan Berggren applied to use on an airborne platform for the purposes of HFDF. To evaluate how useful the 2D Bi-SQUID is we explore multiple signals of the same frequency in two different base sensor configurations: Non-uniform phased array and non-colocated Poynting's Theorem based vector sensors. The exploration is performed using the SPIRIT HPC system to calculate the 2D Bi-SQUID output given multiple incident signals. The AoA estimation calculation is performed using the MUSIC algorithm on the signals received …

Implementation And Performance Of Factorized Backprojection On Low-Cost Commercial-Off-The-Shelf Hardware, Alec C. Rasmussen

Theses and Dissertations

Traditional Synthetic Aperture Radar (SAR) systems are large, complex, and expensive platforms that require significant resources to operate. The size and cost of the platforms limits the potential uses of SAR to strategic level intelligence gathering or large budget research efforts. The purpose of this thesis is to implement the factorized backprojection SAR image processing algorithm in the C++ programming language and test the code's performance on a low cost, low size, weight, and power (SWAP) computer: a Raspberry Pi Model B. For a comparison of performance, a baseline implementation of filtered backprojection is adapted to C++ from pre-existing MATLAB® …