Engineering Commons^™

Positive Rate-Dependent Action Potential Prolongation By Modulating Potassium Ion Channels, Candido Cabo

Publications and Research

Pharmacological agents that prolong action potential duration (APD) to a larger extent at slow rates than at the fast excitation rates typical of ventricular tachycardia exhibit reverse rate dependence. Reverse rate dependence has been linked to the lack of efficacy of class III agents at preventing arrhythmias because the doses required to have an anti-arrhythmic effect at fast rates may have pro-arrhythmic effects at slow rates due to an excessive APD prolongation. In this report we show that, in computer models of the ventricular action potential, APD prolongation by accelerating phase 2 repolarization (by increasing I_Ks) and decelerating …

Evaluation Of Aluminum Dissolution, Current Density, And Pitting Patterns During Electrocoagulation, Monica Castro Carias

USF Tampa Graduate Theses and Dissertations

Electrocoagulation (EC) is a sustainable water treatment process involving the generation of coagulants on-site through the application of a voltage on metal (usually aluminum or iron alloys). The factors that impact EC system performance have been well researched, however further research is needed on the factors that impact anodic dissolution of aluminum electrodes, especially when the technology is transferred to full-scale applications. Electrode fouling is one of the factors that can impact dissolution of the anode during EC due to the formation of a protective oxide/hydroxide layer on the electrode surface. Previous studies have addressed electrode fouling by reversing polarity, …

Improved Performance Of Silica-Supported La0.5Ba0.5Feo3 In The Reverse Water Gas Shift - Chemical Looping Process For Carbon Dioxide Reduction – A Density Functional Theory Study, Jiawei Guo

USF Tampa Graduate Theses and Dissertations

Global warming is increasingly obvious, and the reduction of greenhouse gases is an effective way to heal. Increasing the efficiency of catalysts that is applied in the industry can significantly reduce the emission of greenhouse gases. Reverse water gas shift chemical looping (RWGS-CL) is a promising reaction to convert CO2 to CO. La0.5Ba0.5FeO3 (LBF) is a good candidate for RWGS-CL, which shows increased conversion yield when supported on silica. This research focuses on identifying the mechanism of RWGS-CL via silica-supported LBF by exploring the oxygen vacancy formation energy (EO-vac). Density Functional Theory (DFT) is a powerful computational method to solve …

Degradation Performance Modeling And Optimal Maintenance Planning Of Deteriorating Critical Infrastructures, Hung Q. Nguyen

USF Tampa Graduate Theses and Dissertations

Serving as the backbone of the nation’s economy, a large and growing number of deteriorating critical infrastructures, such as transportation and water infrastructures, are underperforming, aging, becoming structurally deficient, and must be repaired or replaced. Due to the influence of a variety of factors (e.g., material structure, design, operation, and environmental conditions) at different phases of lifecycle and the costly data acquisition process, field degradation of deteriorating infrastructures is highly uncertain with limited degradation data. The co-location and spatial proximity between many infrastructures, such as road and water infrastructures, further makes them physically and operationally interdependent. The sheer deterioration of …

Characterizing Mode Anharmonicity And Huang–Rhys Factors Using Models Of Femtosecond Coherence Spectra, Matthew S. Barclay, Jonathan S. Huff, Ryan D. Pensack, Paul H. Davis, William B. Knowlton, Bernard Yurke, Jacob C. Dean, Paul C. Arpin, Daniel B. Turner

Materials Science and Engineering Faculty Publications and Presentations

Femtosecond laser pulses readily produce coherent quantum beats in transient–absorption spectra. These oscillatory signals often arise from molecular vibrations and therefore may contain information about the excited-state potential energy surface near the Franck–Condon region. Here, by fitting the measured spectra of two laser dyes to microscopic models of femtosecond coherence spectra (FCS) arising from molecular vibrations, we classify coherent quantum-beat signals as fundamentals or overtones and quantify their Huang–Rhys factors and anharmonicity values. We discuss the extracted Huang–Rhys factors in the context of quantum-chemical computations. This work solidifies the use of FCS for analysis of coherent quantum beats arising from …

Schlieren Techniques For Observations Of Long Positive Sparks: Review And Application, Junjia He, Xiankang Wang, Xiangen Zhao, Juhyeong Lee, Yaping Du, Xiaopeng Liu, Quan Gan, Yang Liu, Yuqin Liao

Mechanical and Aerospace Engineering Faculty Publications

Understanding the mechanism of positive leader discharge is important in lightning protection engineering and the external insulation design in high voltage power transmission systems. During the propagation of a positive leader, some processes without light-emitting, for example, the insulation recovery process after the breakdown, cannot be observed by optical photography techniques. With the combination of the digital high-speed imaging system, the conventional Schlieren techniques offer new vistas in the long air gap discharge observation. The important features of high spatial resolution, high sensitivity, and easy arrangement make Schlieren techniques powerful and effective tools for characterising the discharge processes without light-emitting. …

Simulating Flood Control In Progress Village, Florida Using Storm Water Management Model (Swmm), Azize Minaz

USF Tampa Graduate Theses and Dissertations

Flooding is a natural event caused by heavy rains, melting snow, high tides, and anthropogenic impacts such as channel clogging, improper land use, and deforestation. In this study, the strategies for controlling flooding seek to establish flood prevention systems by implementing grey infrastructure and green infrastructure practices. The main objective of this thesis is to analyze the study area, Progress Village Neighborhood in Delaney Creek Watershed, regarding flood risk and flood mitigation techniques. The analysis was performed using EPA SWMM 5.1 and Arcmap 10.7.1. The study used design storms,10-years 24 hours and 25-years 24 hours, to analyze flood risk in …

Hybrid Rans-Les Hemolytic Power Law Modeling Of The Fda Blood Pump, Joseph Tarriela

USF Tampa Graduate Theses and Dissertations

This study applies the SBES and IDDES hybrid RANS-LES turbulence models along with the K-ω SST model to four flow conditions of the FDA blood pump. Validation of all three turbulence models show good agreement with experimental pressure and velocity fields. Evaluation of turbulent kinetic energy fields for the hybrid models show 80-90+% of kinetic energy is resolved in the rotor and diffuser regions of the pump. Hemolysis power law models were evaluated using the commonly used von Mises stress and additional energy dissipation stress (EDS). Results show viscous and Reynolds stresses computed with the K-ω SST under predict and …

Influence Of Admixtures On The Performance Of Soundless Chemical Demolition Agents And Implications For Their Utilization, Nattamon Maneenoi, Raphael Bissen, Sakonvan Chawchai

Journal of Sustainable Mining

Soundless Chemical Demolition Agents (SCDAs) are an environmentally friendly and safer alternative to traditional rock fragmentation methods. Admixtures are used to change the rheological properties and performance of SCDAs. This study aimed to investigate the effect of various concentrations of chemical accelerators (chloride salts) and viscosity enhancing agents (VEAs: Xanthan gum, Guar gum, and Gellan gum) on the fracture onset compared to an unmodified SCDA (BRISTAR 100®). All experiments were conducted on Portland Type 1 (OPC 1) cement blocks. The flowability of the mixtures was determined by mini-slump tests. Results show that 4wt% MgCl2 and 3wt% CaCl2 have accelerated the …

Impedance Analysis Of Anodized Aluminum And Structural Bridge Tendons, Justin Silnutzer

USF Tampa Graduate Theses and Dissertations

This is a two-part thesis with the overall investigation technique being electrochemical impedance spectroscopy (EIS). In the first part, EIS is used to estimate the layer thickness of anodized aluminum oxide. This required the development of an appropriate electrical circuit model; that with parameters that correspond to physical properties of the oxide. In this work, it was found that for thicker oxides of which the outer porous layer is greater than 12 microns, impedance may be used to estimate the outer layer thickness. However, further research is required to understand the role of outer porous layer structure on the impedance …

Computational Methods For Solving The Combinatorial Optimization Problems In Transportation, Xufei Liu

USF Tampa Graduate Theses and Dissertations

This dissertation discusses three transportation problems. The first problem is a bi-level optimization problem that simultaneously optimizes facility locations and network design in hazardous materials transportation. In the upper level, the leader intends to reduce the facility setup cost and the hazmat exposure risk, by choosing facility locations and road segments to close for hazmat transportation. When making such decisions, the leader anticipates the response of the followers who want to minimize the transportation costs. A robust optimization approach with multiplicative uncertain parameters and polyhedral uncertainty sets is applied to deal with the uncertain risk and demand.

The second problem …

Exploration Of Energy Efficient Computing For Data-Intensive Applications, Md Adnan Zaman

USF Tampa Graduate Theses and Dissertations

The recent surge of data-intensive applications has stretched the performance and energy limit of today’s traditional computing system. The massive amount of data generated by data-intensive applications is not processed at the same speed due to bandwidth mismatch between the faster processing unit and slower memory. Memory access and communication bandwidth can be identified as the primary bottlenecks. Consequently, these two bottlenecks make up most of the total energy consumption. In light of this, we explore energy-efficient computing for data-intensive applications. We examine different aspects of two computing systems, such as in-memory computing and AI-enabled edge computing, more popularly known …

Security And Privacy Enhancing Technologies In The Deep Learning Era, Gamage Dumindu Samaraweera

USF Tampa Graduate Theses and Dissertations

Our search queries, online purchase transactions, the videos we watch, and our movie preferences are a few types of information collected and stored daily. This private data collection happens within our mobile devices and computers, on the streets, and in our homes, most of the time even without our consent. Nevertheless, advances in artificial intelligence (AI) in the big data era have increased the capability to capitalize on and benefit from the collection of this private data. Such private data is being used for various machine learning (ML) applications in different domains, such as marketing, insurance, financial services, mobility, social …

Thermophysical Properties Of Inorganic Phase-Change Materials Based On Mncl2·4h2o, Kyung-Eun Min, Jae-Won Jang, Jun-Ki Kim, Chien Wern, Sung Yi

Mechanical and Materials Engineering Faculty Publications and Presentations

Manganese (II) chloride tetrahydrate, classified as an inorganic phase-change material (PCM), can be used as a thermal energy storage material, saving and releasing thermal energy during its phase transitions. In this study, thermophysical properties, such as phase change temperatures, latent heat, and thermal conductivities, of four types of MnCl₂·4H₂O PCMs were investigated under single and dual phases (liquid-, solid-, and dual-phase PCMs) using differential scanning calorimetry (DSC) and a heat flow meter. PCMs with a liquid or dual phases exhibited superheating issues, and their melting temperatures were 7 to 10 °C higher than the reference melting …

Lowering The Technological Barrier In Developing, Sharing And Installing Web Gis Applications, Rohit Kumar Khattar

Theses and Dissertations

Portability of web applications between web servers of different organizations can be challenging and can complicate sharing and collaborative use of such tools. Given the distributed nature of the web, this lack of portability is usually not a concern because a user in one organization can link to and use a web application hosted by another organization. However, access control or differentiation may be needed by an organization in terms of area of interest, input data, analytical techniques, access control, presentation, branding, and language. This is true for many government organizations, and their associated web sites, and servers. In such …

Design And Commissioning Of An E-Beam Irradiation Beamline At The Upgraded Injector Test Facility At Jefferson Lab, Xi Li, Helmut Baumgart, Charles Bott, Gianluigi Ciovati, Shaun Gregory, Fay Hannon, Mike Mccaughan, Robert Pearce, Matthew Poelker, Hannes Vennekate, Shaoheng Wang

Electrical & Computer Engineering Faculty Publications

The Upgraded Injector Test Facility (UITF) at Jefferson Lab is a continuous-wave superconducting linear accelerator capable of providing an electron beam with energy up to 10 MeV. A beamline for electron-beam irradiation has been designed, installed and successfully commissioned at this facility, aimed at the degradation study of 1,4-dioxane and per- and polyfluoroalkyl substances (PFAS) in wastewater treatment. A solenoid with a peak axial magnetic field of up to 0.28 T and a set of raster coils were used to obtain a Gaussian beam profile with a transverse standard deviation of ∼15.0 mm at the target location. Monte-Carlo simulations using …

Through-Ice Acoustic Source Tracking Using Vision Transformers With Ordinal Classification, Steven Whitaker, Andrew Barnard, George D. Anderson, Timothy C. Havens

Michigan Tech Publications, Part 1

Ice environments pose challenges for conventional underwater acoustic localization techniques due to theirmultipath and non-linear nature. In this paper, we compare different deep learning networks, such as Transformers, Convolutional Neural Networks (CNNs), Long Short-Term Memory (LSTM) networks, and Vision Transformers (ViTs), for passive localization and tracking of single moving, on-ice acoustic sources using two underwater acoustic vector sensors. We incorporate ordinal classification as a localization approach and compare the results with other standard methods. We conduct experiments passively recording the acoustic signature of an anthropogenic source on the ice and analyze these data. The results demonstrate that Vision Transformers are …

Cutting-Edge Technologies To Achieve A Higher Level Of Modular Construction – Literature Review, Seungtaek Lee, Jin Ouk Choi, Seung Song

Civil and Environmental Engineering and Construction Faculty Research

Cost overruns, schedule delays, and a shortage of skilled labor are common problems the construction industry is currently experiencing. Modularization and standardization strategies have the potential to resolve the various problems mentioned above and have been applied for various construction applications for a long time. However, the level of modularization remains low, and modular construction projects have not been getting the full benefits. Thus, this review investigated the cutting-edge technologies currently being utilized to develop the modular construction field. For this paper, qualified research papers were identified using predetermined keywords from previous related research papers. Identified literature was then filtered …

Supply Chain Resilience: How Autonomous Rovers Empirically Provide Relief To Constrained Flight Line Maintenance Activities, Mary A. Stanton, Jason Anderson, John M. Dickens, Lance Champagne

Faculty Publications

Purpose – The purpose of this research is to explore the utility of autonomous transport across two independent airframe maintenance operations at a single location. Design/methodology/approach – This study leveraged discrete event simulation that encompassed real-world conditions on a United States Air Force flight line. Though the Theory of Constraints (TOC) lens, a high-demand, human-controlled delivery asset is analyzed and the impact of introducing an autonomous rover delivery vehicle is assessed. The authors’ simulations explored varying numbers and networks of rovers as alternative sources of delivery and evaluated these resources’ impact against current flight line operations. Findings – This research …

Transportation Service Level Impact On Aircraft Availability, Vincent Mclean, Adam D. Reiman

Faculty Publications

Purpose — Aircraft fail to meet mission capable rate goals due to a lack of supply of aircraft parts in inventory where the aircraft breaks. This triggers an order at the repair location. To maximize mission capable rate, the time from order to delivery needs to be minimized. The purpose of this research is to examine the case of three airfields for the order to delivery time of mission critical aircraft parts for a specific aircraft type. Design/methodology/approach — This research captured data from three information systems to assess the order fulfillment process. The data were analyzed to determine the …

Pilot Development: An Empirical Mixed-Method Analysis, Jonathan Slottje, Jason Anderson, John M. Dickens, Adam D. Reiman

Faculty Publications

Purpose — Pilot upgrade training is critical to aircraft and passenger safety. This study aims to identify variances in the US Air Force C-130J pilot upgrade training based on geographic location and provide a model to enhance policy that will impact future pilot training efforts that lower cost and increase operator quality and proficiency.
Design/methodology/approach — This research employed a mixed-method approach. First, the authors collected data and analyzed 90 C-130J pilots' aviation records and then contextualized this analysis with interviews of experts. Finally, the authors present a modified version of Six Sigma's define–measure–analyze–improve–control (DMAIC) that identifies and reduces the …

An Improved Polynomial Chaos Expansion Based Response Surface Method And Its Applications On Frame And Spring Engineering Based Structures, Mhd A. Hafez

ETD Archive

In engineering fields, computational models provide a tool that can simulate a real world response and enhance our understanding of physical phenomenas. However, such models are often computationally expensive with multiple sources of uncertainty related to the model’s input/assumptions. For example, the literature indicates that ligament’s material properties and its insertion site locations have a significant effect on the performance of knee joint models, which makes addressing uncertainty related to them a crucial step to make the computational model more representative of reality. However, previous sensitivity studies were limited due to the computational expense of the models. The high computational …

Analytical And Numerical Solutions To Describe Water Table Fluctuations Due To Canal Seepage And Time-Varying Recharge, Ashutosh Upadhyaya, Manisha M. Kankarej

All Works

Abstract Hybrid finite analytic solution (HFAS), Galerkin's method based finite element solution (FES) and fully implicit finite difference solution (FIFDS) of one dimensional nonlinear Boussinesq equation and Analytical solution of Boussinesq equation linearized by Baumann's transformation (analytical solution I, AS I) as well as linearized by Werner's transformation (analytical solution II, AS II) were employed to obtain water table rise in a horizontal unconfined aquifer lying between two canals located at finite distance having different elevations and subjected to various patterns of recharge, i.e. zero recharge, constant recharge, as well as time varying recharge. Considering HFAS as benchmark solution, water …

The NTh-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems (Nth-Casam-N): Mathematical Framework, Dan Gabriel Cacuci

Faculty Publications

This work presents the n^th-Order Comprehensive Adjoint Sensitivity Analysis Methodology for Nonlinear Systems (n^th-CASAM-N), which enables the most efficient computation of exactly determined expressions of arbitrarily high-order sensitivities of generic nonlinear system responses with respect to model parameters, uncertain boundaries, and internal interfaces in the model’s phase space. The mathematical framework underlying the n^th-CASAM-N is proven to be correct by using mathematical induction. The n^th-CASAM-N is formulated in linearly increasing higher-dimensional Hilbert spaces—as opposed to exponentially increasing parameter-dimensional spaces—thus overcoming the curse of dimensionality in sensitivity analysis of nonlinear systems.

Illustrative Application Of The Nth-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems To The Nordheim–Fuchs Reactor Dynamics/Safety Model, Dan Gabriel Cacuci

Faculty Publications

The application of the recently developed “nth-order comprehensive sensitivity analysis methodology for nonlinear systems” (abbreviated as “nth-CASAM-N”) has been previously illustrated on paradigm nonlinear space-dependent problems. To complement these illustrative applications, this work illustrates the application of the nth-CASAM-N to a paradigm nonlinear time-dependent model chosen from the field of reactor dynamics/safety, namely the well-known Nordheim–Fuchs model. This phenomenological model describes a short-time self-limiting power transient in a nuclear reactor system having a negative temperature coefficient in which a large amount of reactivity is suddenly inserted, either intentionally or by accident. This model is sufficiently complex to demonstrate all the …

Environmental Impact On The Behavior Of Cfrp Sheet Attached To Concrete, Ayssar Al-Khafaji, Ayman El-Zohairy, Mirnes Mustafic, Hani Salim

Faculty Publications

Carbon fiber-reinforced polymer (CFRP) has many advantages as a construction/structural strengthening material. However, there are still concerns regarding the long-term performance of these materials when used with reinforced concrete (RC) structures. Environmental conditions have an adverse effect on the behavior of CFRP and the bond between these sheets and concrete. Therefore, the durability of CFRP used for strengthening RC beams was evaluated under different environmental scenarios, including subjection to immersion in deicing agents, tap water, and saltwater, freeze-and thaw cycles, and outdoor environmental changes. Laboratory tests were performed to examine the influence of these environmental scenarios on the bonding behavior …

Noncontact Liquid Crystalline Broadband Optoacoustic Sensors, Hengky Chandrahalim, Michael T. Dela Cruz

AFIT Patents

An optoacoustic sensor includes a liquid crystal (LC) cell formed between top and bottom plates of transparent material. A transverse grating formed across the LC cell that forms an optical transmission bandgap. A CL is aligned to form a spring-like, tunable Bragg grating that is naturally responsive to external agitations providing a spectral transition regime, or edge, in the optical transmission bandgap of the transverse grating that respond to broadband acoustic waves. The optoacoustic sensor includes a narrowband light source that is oriented to transmit light through the top plate, the LC cell, and the bottom plate. The optoacoustic sensor …

Phased Construction Bridges: Monitoring And Analysis For Traffic-Induced Vibration, Khalid Al-Kady, Christine E. Wittich, Richard L. Wood, George Morcous

Nebraska Department of Transportation: Research Reports

Phased construction is a common technique utilized to allow bridges to remain partially open to traffic throughout the construction process. The segment of the bridge deck that is constructed second cures under the effect of traffic-induced vibration transmitted from the adjacent bridge-deck segment, which is open to traffic. However, subjecting bridge decks to traffic-induced vibration during early-age curing raises concerns about the durability of the decks. The primary goal of this study is to generate a fundamental understanding of the transmission of traffic-induced vibration, the extent of degradation on phased construction bridge decks, and the impact of potential mitigation measures. …

Non-Solvent Induced Phase Separation (Nips) For Fabricating High Filtration Efficiency (Fe) Polymeric Membranes For Face Mask And Air Filtration Applications, Ebuka A. Ogbuoji, Lauren Stephens, Amber Haycraft, Eric Woodridge, C. Escobar

Chemical and Materials Engineering Faculty Publications

Protection against airborne viruses has become very relevant since the outbreak of SARSCoV-2. Nonwoven face masks along with heating, ventilation, and air conditioning (HVAC) filters have been used extensively to reduce infection rates; however, some of these filter materials provide inadequate protection due to insufficient initial filtration efficiency (FE) and FE decrease with time. Flat sheet porous membranes, which have been used extensively to filter waterborne microbes and particulate matter due to their high FE have the potential to filter air pollutants without compromising its FE over time. Therefore, in this study, single layer polysulfone (PSf) membranes were fabricated via …

Machine Learning Applications To Static Timing Analysis, Waseem Mohamed Raslan

Theses and Dissertations

Modeling complex cell behavior is critical for accurate static timing analysis. Effective current source model, ECSM, and composite current source, CCS, waveform data compression became a necessity to reduce the size of technology files and increase the accuracy of the cell characterization data. We used deep learning nonlinear Autoencoders to compress voltage and current waveforms and compared them with singular value decomposition, SVD, approach. Autoencoders gave ~1.67x compression ratio for voltage waveforms better than SVD approach and gave 45x to 55x better compression ratio compared to other lossless techniques like bz2 and gzip. Autoencoders achieved ~1.7x compression ratio for complex …