Engineering Commons^™

Reactions At Noble Metal Contacts With Methylammonium Lead Triiodide Perovskites: Role Of Underpotential Deposition And Electrochemistry, Ross A. Kerner, Philip Schulz, Jeffrey A. Christians, Sean P. Dunfield, Benjia Dou, Lianfeng Zhao, Glenn Teeter, Joseph J. Berry, Barry P. Rand

Faculty Publications

Chemical reactivity of halide perovskites coupled with a low energy of formation makes it a challenge to characterize material properties and achieve long-term device stability. In this study, we elucidate electrochemical reactions occurring at the methylammonium lead triiodide (MAPbI₃)/Au interface. X-ray photoemission spectroscopy is used to identify a type of reduction/oxidation reaction termed underpotential deposition (UPD) involving lead, iodine, and hydrogen occurring at interfaces with noble metals. Changes in surface compositions and oxidation states suggest that UPD derived adsorbates at MAPbI₃/Au interfaces lower the energy barrier for release of volatile HI and/or I₂catalyzing degradation …

The Effect Of Fine And Coarse Recycled Aggregates On Fresh And Mechanical Properties Of Self-Compacting Concrete, Mahmoud Nili, Hossein Sasanipour, Farhad Aslani

Research outputs 2014 to 2021

Today, the use of recycled aggregates as a substitute for a part of the natural aggregates in concrete production is increasing. This approach is essential because the resources for natural aggregates are decreasing in the world. In the present study, the effects of recycled concrete aggregates as a partial replacement for fine (by 50%) and coarse aggregates (by 100%) were examined in the self-compacting concrete mixtures which contain air-entraining agents and silica fumes. Two series of self-compacting concrete mixes have been prepared. In the first series, fine and coarse recycled mixtures respectively with 50% and 100% replacement with air entraining …

Security Framework For The Internet Of Things Leveraging Network Telescopes And Machine Learning, Farooq Israr Ahmed Shaikh

USF Tampa Graduate Theses and Dissertations

The recent advancements in computing and sensor technologies, coupled with improvements in embedded system design methodologies, have resulted in the novel paradigm called the Internet of Things (IoT). IoT is essentially a network of small embedded devices enabled with sensing capabilities that can interact with multiple entities to relay information about their environments. This sensing information can also be stored in the cloud for further analysis, thereby reducing storage requirements on the devices themselves. The above factors, coupled with the ever increasing needs of modern society to stay connected at all times, has resulted in IoT technology penetrating all facets …

Surface-Controlled Dissolution Rates: A Case Study Of Nanoceria In Carboxylic Acid Solutions, Eric A. Grulke, Matthew J. Beck, Robert A. Yokel, Jason M. Unrine, Uschi M. Graham, Matthew L. Hancock

Chemical and Materials Engineering Faculty Publications

Nanoparticle dissolution in local milieu can affect their ecotoxicity and therapeutic applications. For example, carboxylic acid release from plant roots can solubilize nanoceria in the rhizosphere, affecting cerium uptake in plants. Nanoparticle dispersions were dialyzed against ten carboxylic acid solutions for up to 30 weeks; the membrane passed cerium-ligand complexes but not nanoceria. Dispersion and solution samples were analyzed for cerium by inductively coupled plasma mass spectrometry (ICP-MS). Particle size and shape distributions were measured by transmission electron microscopy (TEM). Nanoceria dissolved in all carboxylic acid solutions, leading to cascades of progressively smaller nanoparticles and producing soluble products. The dissolution …

Multi-Phase-Shift Control Of A Power Converter, Allan Ray Taylor, Alan Wayne Brown, Philip Michael Johnson

Electrical & Computer Engineering Patents

Multi-phase-shift control of a power converter is provided. The power converter includes a dual-active-bridge (DAB) converter having a transformer, a first H-bridge coupled to the primary winding of the transformer, and a second H-bridge coupled to the secondary winding of the transformer. The DAB converter is operable to generate two-level and three-level voltage waveforms on the primary winding and on the secondary winding to yield a system which ensures zero-voltage switching and unity power factor over a wide range of input and output voltage levels and power throughputs. In a multi-phase shift (MPS) mode of operation, the DAB converter changes …

Lowering Emissivity Of Concrete Roof Tile's Underside Cuts Down Heat Entry To The Building, Xuejun Chen, Lei Wang, Zhikui Liu, Yinghong Qin, Ting Bao

Department of Civil, Environmental, and Geospatial Engineering Publications

Buildings in Southern China widely use a double-skin roof to reduce heat entry through the roof to the building interior during summertime. Concrete roof tiles are preferably installed as the outmost layer of the double-skin roof due to their resistance to hail and wind damages and their attractive price. However, after construction, the tile’s top tends to be darkened by dust deposit and algae growth, increasing the heat entry through the roof to the building. Here, we show that this heat entry can be curtailed by lowering the emissivity at the tile’s underside. Temperatures and heat fluxes at different elevations …

Synthesis And Characterization Of Molybdenum Disulfide/Conducting Polymer Nanocomposite Materials For Supercapacitor Applications, Turki S. Alamro

USF Tampa Graduate Theses and Dissertations

The needs for energy storage devices have kindled researchers desire to explore and synthesize nanocomposite materials. Storing energy efficiently, effectively and sustainably are the science and engineering communities’ highest priorities to develop electrochemical energy storage devices. Supercapacitors have become power solution not only because supercapacitors can bridge the gap between the traditional capacitors and rechargeable batteries but also because of many other advantages which include extraordinary electrochemical properties, wide working-temperature range, cost effective, safe operation and long/stable cycle life. They have higher current pules than batteries due to the mechanism of charging and discharging. Batteries charging and discharging via chemical …

Essays On Time Series And Machine Learning Techniques For Risk Management, Michael Kotarinos

USF Tampa Graduate Theses and Dissertations

The Capital Asset Pricing Model combined with the Sharpe ratio is a standard method for choosing assets for selection in a portfolio. However, this method has many structural issues and was designed for a time when high dimensional computing was in its infancy. An alternative to these methods using a mix of Multi-Level Time Series Clustering, the MACBETH algorithm and traditional time series techniques was constructed that minimized data loss and allow for customized portfolio construction for investors with different risk profiles and specialized investment needs. It was shown that these methods are adaptable to cloud computing environments and allow …

Progress On Longitudinal Study Of The Impact Of Growth Mindset And Belonging Interventions In A Freshman Engineering Class, Jinny Rhee, Camille Johnson

Faculty Publications

Growth mindset and belonging interventions have shown to be effective in increasing retention and performance in some K-12 and postsecondary populations. These interventions hold the promise of cost-effective and scalable interventions that may be able to boost retention and graduation rates, and close the achievement gap that often exists between underrepresented (URM) students and non-URMs.A study of the impact of growth mindset and belonging interventions was designed and implemented in the 2015-2016 academic year in an Introduction to Engineering Course typically taken in the freshman year of all engineering and technology programs at a large comprehensive public university. The interventions …

Biodegradable Polymeric Film For Food Packaging, Neelam Yadav, Raminder Kaur

Journal of Applied Packaging Research

Food packaging films that show post-consumer biodegradability are rarely explored by researchers. The present study was carried out to investigate the physicomechanical characteristics of ethyl cellulose (EC) based films to be used in food packaging. Ethyl cellulose was plasticized with different percentage of polyethylene glycol (PEG). The samples of standard dimensions were subjected to different testing such as soluble matter content, moisture content, oil permeability, surface morphology, mechanical testing etc. The data obtained was analysed to decide the moderate percentage of plasticizer that can be used to provide a rational explanation of a perfect quality specimen. It has been revealed …

Comparison Of Organic Food Packaging In Denmark, Finland, Germany, Great Britain And Italy, Sara Paunonen, Marja Pitkänen, Mika Vähä-Nissi, Ville Leminen, Mika Kainusalmi

Journal of Applied Packaging Research

The objective of this study was to provide a snapshot of organic food assortments in supermarkets in Denmark, Finland, Germany, Great Britain, and Italy, and compare the packages used for five organic food products (eggs, meat, fish, mushrooms, berries). In addition, a comparison was made between packaging for regular and organic whole eggs. The highest number of organic products was found in the Danish supermarket. The main difference between the countries was in the use of national organic logos. Of the different food products, egg cartons had the most variation in materials and visual design. In all countries the product …

Identification And Reduction Of Uncertainties In Watershed-Scale Flow And Water Quality Modeling, Maryam Roostaee

LSU Doctoral Dissertations

This study identified important uncertainties affecting watershed-scale flow and water quality simulations and recommended modeling options for reducing the uncertainties by means of the Hydrological Simulation Program-FORTRAN (HSPF) model. Specifically, parameter-induced uncertainties in HSPF model were estimated along with uncertainties associated with DEM resolutions and sources. National Elevation Dataset (NED) DEMs with original and resampled resolutions of 3.5, 10, 30 and 100m were utilized for manual and automatic delineation of three watersheds with different gradients in HSPF model to identify the effects of DEM resolution, DEM resampling, delineation method and watershed gradient on the simulation of streamflow, nitrate (NO_{3 …}

Professor Receives Award From The Center For Women And Gender | College Of Engineering, Utah State University

College of Engineering News

USU engineering professor, Elizabeth Vargis was awarded the ‘Early Career-Faculty award’ from the Center for Women and Gender.

Fluoride Removal From Water Using A 3d Printed Calcium Carbonate Filter, Sophia Bakar, David Kahler, Benjamin S. Goldschmidt

Undergraduate Research and Scholarship Symposium

Groundwater containing high concentrations of fluoride is the most common source of drinking water in rural areas in parts of east Africa, India, and China. The elevated levels of fluoride cause skeletal and dental fluorosis, which is the weakening and decay of bone structures due to the leeching of calcium from the body as calcium and fluoride bond by the process of adsorption. Over 150 million people are suffering from some form of fluorosis due to the consumption of groundwater. Calcium carbonate has been demonstrated to influence fluoride removal in several forms. To make fluoride removal a cost-effective and user-friendly …

Quantifying Iron Overload Using Mri, Active Contours, And Convolutional Neural Networks, Andrea Sajewski, Stacey Levine

Undergraduate Research and Scholarship Symposium

Iron overload, a complication of repeated blood transfusions, can cause tissue damage and organ failure. The body has no regulatory mechanism to excrete excess iron, so iron overload must be closely monitored to guide therapy and measure treatment response. The concentration of iron in the liver is a reliable marker for total body iron content and is now measured noninvasively with magnetic resonance imaging (MRI). MRI produces a diagnostic image by measuring the signals emitted from the body in the presence of a constant magnetic field and radiofrequency pulses. At each pixel, the signal decay constant, T2*, can be calculated, …

Routing And Designing Networks For Two Transportation Problems, Liu Su

USF Tampa Graduate Theses and Dissertations

Routing and designing are essential for transportation networks. With effective routing and designing policies, transportation networks can work safely and efficiently. There are two transportation problems: hazardous materials (hazmat) transportation and warehouse logistics. This dissertation addresses the routing of networks for both problems. For hazmat transportation, the routing can be regulated via network design. Due to catastrophic consequences of potential accidents in hazmat transportation, a risk-averse approach for routing is necessary. In this dissertation, we consider spectral risk measures, for risk-averse hazmat routing. In addition, we introduce a network design problem to select a set of closed road segments for …

Convolutional Neural Networks For Crystal Material Property Prediction Using Hybrid Orbital-Field Matrix And Magpie Descriptors, Zhuo Cao, Yabo Dan, Zheng Xiong, Chengcheng Niu, Xiang Li, Songrong Qian, Jianjun Hu

Faculty Publications

Computational prediction of crystal materials properties can help to do large-scale in-silicon screening. Recent studies of material informatics have focused on expert design of multi-dimensional interpretable material descriptors/features. However, successes of deep learning such as Convolutional Neural Networks (CNN) in image recognition and speech recognition have demonstrated their automated feature extraction capability to effectively capture the characteristics of the data and achieve superior prediction performance. Here, we propose CNN-OFM-Magpie, a CNN model with OFM (Orbital-field Matrix) and Magpie descriptors to predict the formation energy of 4030 crystal material by exploiting the complementarity of two-dimensional OFM features and Magpie features. Experiments …

Application Of The Clayff And The Dreiding Force Fields For Modeling Of Alkylated Quartz Surfaces, Aleksandr Abramov, Stefan Iglauer

Research outputs 2014 to 2021

To extend applicability and to overcome limitations of combining rules for nonbond potential parameters, in this study, CLAYFF and DREIDING force fields are coupled at the level of atomic site charges to model quartz surfaces with chemisorpt hydrocarbons. Density functional theory and Bader charge analysis are applied to calculate charges of atoms of the OC bond connecting a quartz crystal and an alkyl group. The study demonstrates that the hydrogen atom of the quartz surface hydroxyl group can be removed and its charge can be redistributed among the oxygen and carbon atoms of the OC bond in a manner consistent …

Low-Cost, Open-Source, And Low-Power: But What To Do With The Data?, Jeffery S. Horsburgh, Juan Caraballo, Maurier Ramírez, Anthony K. Aufdenkampe, David B. Arscott, Sara Geleskie Damiano

Civil and Environmental Engineering Faculty Publications

There are now many ongoing efforts to develop low-cost, open-source, low-power sensors and datalogging solutions for environmental monitoring applications. Many of these have advanced to the point that high quality scientific measurements can be made using relatively inexpensive and increasingly off-the-shelf components. With the development of these innovative systems, however, comes the ability to generate large volumes of high-frequency monitoring data and the challenge of how to log, transmit, store, and share the resulting data. This paper describes a new web application that was designed to enable citizen scientists to stream sensor data from a network of Arduino-based dataloggers to …

An Optimization Approach Based On The Interior-Point Methodology For The Tertiary Control Of Modernized Microgrids, Isaiah D. Woodruff

Honors College Theses

With the rise in popularity of the modernized microgrids (MMGs), the addition of a controller to maximize economic efficiency while considering environmental impact is crucial. Tertiary control is at the highest control level, considering economic concerns related to the optimal operation of the microgrid and using a sampling time from minutes to hours; tertiary controls manage the flow of power between the microgrid and the connected grid. In MMGs' tertiary controls, the use of optimization algorithms to minimize an objective function with equality and inequality constraints allows for powerful control over the system. In this paper, the interior-point algorithm is …

General Aviation Hypoxia And Reporting Statistics, Timothy Holt, Jacqueline Luedtke, Jennah Perry, Michelle Hight, Claire Schindler, Pamela Ward

Journal of Aviation Technology and Engineering

Hypoxia is defined as a lack of oxygen throughout the body, which can be caused by several factors at any altitude. General aviation (GA) pilots may argue that most GA aircraft cannot attain the required altitudes where one might be more affected by hypoxia, but it is exactly that attitude that may makes pilots more susceptible to hypoxia. The impact of this hazardous attitude is even more apparent if one considers that out of the 590,038 certificated pilots in the USA, a little over 30% of them are GA pilots (FAA, 2015). The problem is that unlike airline pilots or …

Green Synthesis Nanocomposite Membranes, Dibakar Bhattacharyya, Vasile Smuleac, Rajender S. Varma, Subhas K. Sikdar

Chemical and Materials Engineering Faculty Patents

A nanocomposite membrane includes a macroporous polymer membrane having a plurality of pores. A plurality of metal nanoparticles are synthesized and immobilized within those plurality of pores. The nanoparticles are reduced and capped with a green reducing and capping agent such as green tea extract.

Novel Calibrated Short Tr Recovery (Castrr) Method For Brain-Blood Partition Coefficient Correction Enhances Gray-White Matter Contrast In Blood Flow Measurements In Mice, Scott W. Thalman, David K. Powell, Ai-Ling Lin

Biomedical Engineering Faculty Publications

The goal of the study was to develop a novel, rapid Calibrated Short TR Recovery (CaSTRR) method to measure the brain-blood partition coefficient (BBPC) in mice. The BBPC is necessary for quantifying cerebral blood flow (CBF) using tracer-based techniques like arterial spin labeling (ASL), but previous techniques required prohibitively long acquisition times so a constant BBPC equal to 0.9 mL/g is typically used regardless of studied species, condition, or disease. An accelerated method of BBPC correction could improve regional specificity in CBF maps particularly in white matter. Male C57Bl/6N mice (n = 8) were scanned at 7T using CaSTRR …

Aviation Safety, Quality, And Economic Impact: A Policy Research System, Calissa Spooner, Tori Kobayashi, Cindy Greenman, Brent D. Bowen, Kaetlyn Blocker

Student Works

The United States airline industry is experiencing an underlying mix of challenges in areas of Quality, Safety, and Economics. This research focuses on three major components and the economic impact of each. The first aspect, Airline Quality and Safety Analysis, lays down a focus on imperative safety factors that affect major airlines in overall performance. Quality and Safety findings relate to potential safety shortcomings in the second aspect, aviation maintenance Safety Management Systems (SMS). The third aspect involves implementing the Policy Research Construct (PRC) methodology, which relates the underlying challenges in Airline Quality, Safety, and Economic areas by conducting research …

Information Technology News, Georgia Southern University

Information Technology: News & Publications (2012-2023)

• Synovus Information Security Co-op -- Columbus, GA

Nematic Liquid Crystal Composite Materials For Dc And Rf Switching, Mohiuddin Munna, Farhana Anwar, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

Liquid Crystals (LCs) are widely used in display devices, electro-optic modulators, and optical switches. A field-induced electrical conductivity modulation in pure liquid crystals is very low which makes it less preferable for direct current (DC) and radio-frequency (RF) switching applications. According to the literature, a conductivity enhancement is possible by nanoparticle doping. Considering this aspect, we reviewed published works focused on an electric field-induced conductivity modulation in carbon nanotube-doped liquid crystal composites (LC-CNT composites). A two to four order of magnitude switching in electrical conductivity is observed by several groups. Both in-plane and out-of-plane device configurations are used. In plane …

Examining The Effect Of Multiple Route Choice Criteria On Hurricane Evacuation Traffic Through External Validation Of Simulations, Haggai D. Davis Iii

LSU Master's Theses

Hurricane evacuations can be a chaotic experience for individuals involved, but researchers have attempted to find patterns in the routes people take. One paper laid out a model for predicting route choice based upon features that are different than standard route choice influencers. This thesis attempted to evaluate the accuracy of that model by using TransModeler modeling software. Using the building blocks of the HEMP project, this project compared the new model to the standard model and evaluated the two based upon the ability to reproduce real-world results. Interestingly, the two did not come out significantly different possibly because the …

Influence Of Sonication Parameters On The Morphology Of Nanocellulose Aerogels, Dexter Cox, Tim Kidd

Research in the Capitol

Nanocellulose is a renewable and biocompatible material that has a tensile strength similar to aluminum, is stiffer than Kevlar, and has a strength to weight ratio eight times that of stainless steel. There has been a range of studies on nanocellulose materials for potential use as a low-calorie food substitute, biomedical wound dressings, and as a structural component for buildings. Throughout this research experiment, nanocellulose aerogels of different mass compositions were created through a mechanical process using an ultrasonic processor with a titanium probe attachment. The purpose of this study was to develop a method that reduces the amount titanium …

Dual-Battery Empowered Green Cellular Networks, Xilong Liu

Dissertations

With awareness of the potential harmful effects to the environment and climate change, on-grid brown energy consumption of information and communications technology (ICT) has drawn much attention. Cellular base stations (BSs) are among the major energy guzzlers in ICT, and their contributions to the global carbon emissions increase sustainedly. It is essential to leverage green energy to power BSs to reduce their on-grid brown energy consumption. However, in order to furthest save on-grid brown energy and decrease the on-grid brown energy electricity expenses, most existing green energy related works only pursue to maximize the green energy utilization while compromising the …

Scu Courses, Conner Davis, Matthew Wong

Computer Science and Engineering Senior Theses

Registering for classes is a nightmare that students at Santa Clara University undergo three or more times a year while juggling midterm exams. It’s hard to find a schedule that works well for you, balancing the need to take classes that will satisfy degree progress with the need to work around obligations outside of class and avoid getting stuck in an 8am lecture. SCU Courses is a web app where students input their current degree progress and receive a list of possible schedules to take next quarter, collapsing the time-consuming process of carefully crafting a schedule into just one step: …