Civil Engineering Commons^™

Experimental Study And Piezoresistive Mechanism Of Electrostatic Self-Assembly Of Carbon Nanotubes–Carbon Black/Epoxy Nanocomposites For Structural Health Monitoring, Yanlei Wang, Yao Fu, Ziping Meng, Baolin Wan, Baoguo Han

Civil and Environmental Engineering Faculty Research and Publications

Since electrostatic self-assembly carbon nanotubes–carbon black (CNTs–CB) composite fillers have good electrical conductivity and an easy dispersion process, they were incorporated into epoxy matrix to fabricate the CNTs–CB/epoxy nanocomposites. The mechanical properties, electrical conductivity, piezoresistivity, as well as microstructure characterization of the CNTs–CB/epoxy nanocomposites were experimentally investigated. The piezoresistive mechanisms of the CNTs–CB/epoxy nanocomposites were also established based on tunneling conduction and contacting conduction. The significant improvements in compressive yielding strength and elastic modulus of the nanocomposites could be attributed to the stable interfacial interaction. A moderate percolation threshold was obtained at 0.41 vol% for the CNTs–CB/epoxy nanocomposites in comparison …

Meta-Analysis Of The Prevalence Of Dissolved Organic Nitrogen (Don) In Water And Wastewater And Review Of Don Removal And Recovery Strategies, Synthia P. Mallick, Zayed Mallick, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Most wastewater removal and recovery processes primarily target dissolved inorganic nitrogen (DIN) species, leaving the untreated non-reactive dissolved organic nitrogen (DON) in the effluent. This DON fraction can account for a substantial part of the total nitrogen (N) load. We analyzed large datasets of N species and concentrations (with a focus on quantifying the fraction of DON) in surface water, ground water, and wastewater effluent across the United States. We then reviewed strategies to remove and recover DON based on results of a range of treatment technologies reported in the literature, including laboratory-scale up to full-scale operation in wastewater treatment …

Simple Rebar Anchorage Slip Macromodel Considering Corrosion, Ahmad Soraghi, Qindan Huang

Civil and Environmental Engineering Faculty Research and Publications

Reinforcement slip in the footing of a reinforced concrete (RC) column can significantly influence the lateral displacement of the column, a critical structural response under lateral loads such as seismic loading. Many past researchers studied and developed models to capture the anchorage slip of rebar; however, there is still a need for a model that can reflect the actual bond-slip relationship (especially in the presence of corrosion) and yet is simple-to-use for structural analysis. In this study, a simple bar stress-slip macromodel is developed to predict reinforcement anchorage slip given a rebar stress. The proposed rebar anchorage slip model is …

Lab-Scale Data And Microbial Community Structure Suggest Shortcut Nitrogen Removal As The Predominant Nitrogen Removal Mechanism In Post-Aerobic Digestion (Pad), Fabrizio Sabba, Patrick J. Mcnamara, Eric Redmond, Mike Young, Leon Downing

Civil and Environmental Engineering Faculty Research and Publications

Implementing an aerobic digestion step after anaerobic digestion, referred to as “post aerobic digestion” (PAD), can remove ammonia without the need for an external carbon source and destroy volatile solids. While this process has been documented at the lab-scale and full-scale, the mechanism for N removal and the corresponding microbial community that carries out this process have not been established. This research gap is important to fill because the nitrogen removal pathway has implications on aeration requirements and carbon demand, that is, short-cut N-removal requires less oxygen and carbon than simultaneous nitrification–denitrification. The aims of this research were to (i) …

Seasonal And Spatial Patterns Differ Between Intracellular And Extracellular Antibiotic Resistance Genes In Urban Stormwater Runoff, Kassidy N. O'Malley, Patrick J. Mcnamara, Walter M. Mcdonald

Civil and Environmental Engineering Faculty Research and Publications

Antibiotic resistance is a public health threat that is exacerbated by the dispersion of antibiotic resistance genes (ARGs) into aquatic environments. Urban stormwater runoff has been recognized as a source of and a mechanism by which intracellular ARGs (iARGs) can be transported into receiving environments. The prevalence and behavior of extracellular ARGs (eARGs) in stormwater, however, has yet to be considered. This study quantified four iARGs and eARGs under baseflow and stormflow conditions. Urban stormwater runoff was found to be a source of all the ARGs examined, with the absolute concentration of all iARGs and two eARGs (ermF …

Building Services Engineering July/August 2022

Building Services Engineering

No abstract provided.

Sequential Electrolysis And Reverse Osmosis To Improve Arsenic Removal From Water, Yizhi Hou, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Reverse osmosis (RO) typically removes >98% arsenate (As[V]) but removes arsenite (As[III]) comparatively poorly (approximately 50%–80%). Therefore, oxidizing As(III) to As(V) can improve arsenic removal using RO. In this study, electrolytic oxidation was used to oxidize As(III) in the feed water, and an extreme low-pressure RO membrane was subsequently used to remove the arsenic. Using Ti/IrO2 electrodes under 30 mA DC current in 500 mg/L NaCl solution primarily generated free chlorine, which completely oxidized 300 μg/L As(III) to As(V). Subsequent arsenic removal by RO increased from 54.2% without oxidation to 98.2% with oxidation. Using electrolysis-RO, arsenic removal significantly increased beyond …

Oxidized Graphitic Nano-Amendment Of Cement Composites: Exploring Truly Low Concentrations And Novel Particle Morphologies, Shohana Iffat

Theses and Dissertations

Oxidized graphitic nanoparticles such as multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs), can produce enhancements in physicomechanical properties of cement composites that are relevant to structural and durability performance, provided that said nanoparticles are well dispersed in the composite. Lower-bound MWCNT concentrations are reported in the literature in the range 0.01-0.05% in weight of cement (wt%). Such concentrations may not be costeffective for practical applications and may also be excessive since they would result in a nanoparticle surface area at or above 105 m2 for 1 m3 of cement paste, or 104.5 m2 for 1 m 3 of concrete, …

Changes In Drought Characteristics Under Future Climate Projections, Diogo Stalin De Alcantara Araujo

Theses and Dissertations

Accumulating evidence on the impact of climate change on droughts, highlight the necessity for developing effective adaptation and mitigation strategies. Global Drought Layers were developed for historic and future runs of nine global climate models (GCM) of the Coupled Model Intercomparison Model 6th phase (CMIP6). Relative changes of drought characteristics were estimated, and hotspots were identified, especially in South America, Africa, Europe, Western USA, and Australia. Further, changes in future drought risk and severity in Australia are quantified. Historic conditions (1981-2014) and projections for mid-century (2015-2050) and end-century (2051-2100) from four shared socioeconomic pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5) are …

Circular Reinforced Concrete Columns Damaged By Fire And Retrofitted With Cfrp And Steel Jacketing, Jia Xu

Dissertations - ALL

In recent decades, the post-fire behavior of reinforced concrete (RC) columns with normal and high-strength concrete has become an important research topic. Numerous studies have demonstrated that RC columns exhibit good fire resistance owing to the thermal properties of concrete. Therefore, reinforced concrete structures rarely collapse within a finite fire duration and can be successfully repaired. Along with the increasing number of skyscrapers, high-strength concrete (HSC) has played an equally important role as normal-strength concrete (NSC) in the industry. In this study, the thermal behavior of RC columns with NSC and HSC exposed to ISO 834 standard fire for various …

Data-Driven Prioritization And Empirical Predictions For Bridge Scour In Nebraska, Awgku Ahmad Hashim Awg Bolhasan

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The effect of scour at the bridge substructure results in an increase in the vulnerability of the overall bridge stability. Previous studies have found that current guidelines are often overly-conservative with respect to scour. This project aims to provide guidance on hydraulic modeling parameters and reasonable scour estimates specific to Nebraska conditions. This will enable engineers to assess bridge sites for scour more precisely for efficient and effective design and countermeasures.

Four sites were surveyed for scour changes between the period of December 9, 2020, to April 20, 2021. At these four sites, overland and bathymetry survey data were collected. …

Investigating The Proper Use Of Litani River Basin Based On Water Quality, Mohamad Diab, Mohamad Soliman

BAU Journal - Science and Technology

Litani River Basin (LRB) with a 170km length and annual river flow of 750 MCM is considered the most important water resource in Lebanon. Unfortunately, the river is facing water contamination as a result of human practices. Water Quality assessments was performed in the Litani River Basin using a combination of Principal Component Analysis method (PCA) and Water Quality Index method (WQI). Results revealed the improvement of the water quality significantly after passing lake Qaraoun. Moreover, according to WQI, Lower LRB water is ranked ‘’Good’’ for irrigation and ‘’BAD’ for drinking purposes. Microbial contamination is found to be the key …

Mechanical And Durability Properties Of Geopolymer Concrete – A Review, Lelian Elkhatib, Fadi Al Aridi, Adel Elkordi, Jamal Khatib

BAU Journal - Science and Technology

Owing to the ongoing increase in human population, there is a need for more construction projects including residential buildings and other amenities. Concrete is by far the dominant material used in construction and cement is a main ingredient. Cement manufacture is an energy intensive process and emit large amounts of carbon dioxide into the atmosphere. A reduction in the amount of cement used in construction is greatly beneficial. The use of geopolymer or alkali activated materials can serve this purpose as it attempts to totally replace cement in concrete. Geopolymers are materials that consist mainly of silica and alumina materials …

Production Of Low-Cost Self-Consolidating Concrete (Scc) Using Manufactured Aggregates, Rabab Raydan, Farah Chamseddine, Ali Jahami, Oussama Baalbaki, Jamal Khatib, Adel Elkordi

BAU Journal - Science and Technology

Limitations to the sources of aggregates and the unavailability of sand is becoming a problematic issue for concrete production. A novel technology of manufactured aggregates can produce well graded round aggregates that can substitute natural aggregates while maintaining the same characteristics needed and preserving the resources. Self-Consolidating Concrete (SCC) using manufactured aggregates is assessed in this experimental work to understand the variability of workability properties and mechanical properties with the changes in w/c ratio and percentages of Coarse Aggregates and Manufactured Sand to Natural Sand in order to choose the best mixture that satisfies an adequate overall performance. Targeting compressive …

Passive Radiative Cooling By Spectrally Selective Nanoparticles In Thick Film Nanocomposites, David Allen Young

USF Tampa Graduate Theses and Dissertations

Passive cooling of buildings is a benefit to society since no energy input is required for space cooling which reduces electricity consumption, fossil fuel burning, and greenhouse gas emissions. When a passive cooling technology radiates heat from the earth through the atmospheric windows to space higher levels of cooling power are possible -- this phenomenon is classified as passive “radiative” cooling. Spectrally selective surface coatings provide radiative cooling to lower surface temperatures by reflecting most solar radiation, while emitting infrared radiation at wavelengths between 8-13 μm through the primary atmospheric window to the cold of space. Multiple applications of radiative …

Unconventional Water Resources: Global Opportunities And Challenges, Zahra Karimidastenaei, Tamara Avellán, Mojtaba Sadegh, Bjørn Kløve, Ali Torabi Haghighi

Civil Engineering Faculty Publications and Presentations

Water is of central importance for reaching the Sustainable Development Goals (SDGs) of the United Nations. With predictions of dire global water scarcity, attention is turning to resources that are considered to be unconventional, and hence called Unconventional Water Resources (UWRs). These are considered as supplementary water resources that need specialized processes to be used as water supply. The literature encompasses a vast number of studies on various UWRs and their usefulness in certain environmental and/or socio-economic contexts. However, a recent, all-encompassing article that brings the collective knowledge on UWRs together is missing. Considering the increasing importance of UWRs in …

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, …

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 …

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 …

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 …

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 …

Effects Of Slurry Type On Drilled Shaft Strength, Cesar Quesada Garcia

USF Tampa Graduate Theses and Dissertations

The main objective of this research is to identify how the strength of drilled shafts is affected by the use of various types of drill slurry. When concrete is placed in drilled shafts it flows out radially and a laitance interface forms creating a crease on the backside of the reinforcement cage due to the laitance trapped in concrete flowing around the rebar. This can cause concrete to not fully encapsulate the steel making the shafts prone to corrosion and the strength of the cover concrete is locally reduced. Over the past 9 years 58, 42-inch diameter shafts have been …

Tensile Strain And Damage Self-Sensing Of Flax Frp Laminates Using Carbon Nanofiber Conductive Network Coupled With Acoustic Emission, Yanlei Wang, Guipeng Chen, Yongshuai Wang, Baoguo Han, Baolin Wan, Qingduo Hao, Yulei Bai

Civil and Environmental Engineering Faculty Research and Publications

The strain and damage self-sensing properties of carbon nanofibers (CNFs)/flax fiber-reinforced polymer (FFRP) laminates under tension were investigated via simultaneously measuring the changes of electrical resistance (ER) and acoustic emission (AE) signals. The piezoresistive mechanisms together with the damage evolution of CNFs/FFRP laminates were also explored. The results revealed that both ER and AE responses to tensile strains in CNFs/FFRP laminates could be segmented into three stages, which confirmed their good damage self-sensing ability. The isochronous and reversible electrical resistance responses to tensile strains proved the stability and repeatability of strain self-sensing capability for CNFs/FFRP laminates. Moreover, in-situ ER measurement …

Characterizing The Chemical And Microbial Fingerprint Of Unsheltered Homelessness In An Urban Watershed, Daniel Gerrity, Katerina Papp, Eric Dickenson, Meena Ejjada, Erica Marti, Oscar Quinones, Mayra Sarria, Kyle Thompson, Rebecca A. Trenholm

Civil and Environmental Engineering and Construction Faculty Research

Unsheltered homelessness is rapidly becoming a critical issue in many cities worldwide. The worsening situation not only highlights the socioeconomic plight, but it also raises awareness of ancillary issues such as the potential implications for urban water quality. The objective of this study was to simultaneously leverage diverse source tracking tools to develop a chemical and microbial fingerprint describing the relative contribution of direct human inputs into Las Vegas' tributary washes. By evaluating a wide range of urban water matrices using general water quality parameters, fecal indicator bacteria (FIB), human-associated microbial markers [e.g., HF183, crAssphage, and pepper mild mottle virus …

Fault Tolerance Analysis Of An Adaptive Neuro-Fuzzy Inference System For Mandatory Lane Changing Decisions In Automated Driving, Matthew Vechione, Ruey Long Cheu

Civil Engineering Faculty Publications and Presentations

Past research has developed a binary decision model for mandatory lane changes based on the Adaptive Neuro-Fuzzy Inference System (ANFIS). This ANFIS Decision Model (simply called ADEM), developed and tested with the Next Generation Simulation (NGSIM) data, mimics the sensory inputs and decisions of human drivers. This research assumed that ADEM will be implemented as part of the automated lane changing system in Automated Vehicles (AVs). The system in AVs will depend on active radar sensors to make measurements. The sensor outputs will be converted into the input parameter values of ADEM. This research tested ADEM's performance when the sensors …

Characterization And Performance Enhancement Of Cement-Based Thermoelectric Materials, Ruchita Jani, Niall Holmes Dr., Roger West, Kevin Gaughan, Xiaoli Liu, Ming Qu, Esther Orisakwee, Lorenzo Stella, Jorge Kohanoff, Hongxi Yin, Bartlomiej Wojciechowski

Articles

Thermoelectric materials enable the direct conversion of thermal to electrical energy. One application of this is ambient heat energy harvesting where relatively stable temperature gradients existing between the inside and outside of a building could be utilized to produce electricity. Buildings can thus change from energy consumers to energy generators. This could ultimately help reduce the surface temperatures and energy consumption of buildings, especially in urban areas. In this paper, research work carried out on developing and characterizing a cement-based thermoelectric material is presented. Cement-based samples are doped with different metal oxides (Bi2O3 and Fe2O3) to enhance their thermoelectric properties, …

Discrepancies In Changes In Precipitation Characteristics Over The Contiguous United States Based On Six Daily Gridded Precipitation Datasets, Mojtaba Sadegh

Civil Engineering Faculty Publications and Presentations

Variability and spatiotemporal changes in precipitation characteristics can have profound socioenvironmental impacts. Several studies have shown that the frequency and/or magnitude of precipitation events have changed over the contiguous United States (CONUS) in the past decades. Most previous studies used only one precipitation dataset and only investigated mean or extreme precipitation. Here, using 6 gridded daily precipitation datasets, we show that there are substantial discrepancies in the changes in characteristics of both extreme and non-extreme precipitation events from 1983 to 2017. Our results highlight that using a single record to study precipitation changes can potentially lead to biased results. Using …

Coevolution Of Machine Learning And Process-Based Modelling To Revolutionize Earth And Environmental Sciences: A Perspective, Mojtaba Sadegh

Civil Engineering Faculty Publications and Presentations

Machine learning (ML) applications in Earth and environmental sciences (EES) have gained incredible momentum in recent years. However, these ML applications have largely evolved in ‘isolation’ from the mechanistic, process-based modelling (PBM) paradigms, which have historically been the cornerstone of scientific discovery and policy support. In this perspective, we assert that the cultural barriers between the ML and PBM communities limit the potential of ML, and even its ‘hybridization’ with PBM, for EES applications. Fundamental, but often ignored, differences between ML and PBM are discussed as well as their strengths and weaknesses in light of three overarching modelling objectives in …

Feasibility Report On Water Recycling And The Housing Crisis, Tally A. Perry

City and Regional Planning

The western United States is experiencing increasing population, a housing shortage, and a drought. These challenges demand creative and unprecedented changes to development. Water recycling is slowly emerging as a viable solution for developers, home owners, and cities as a way to continue much-needed housing development while mitigating unnecessary water depletion. With all change, policy, feasibility, and awareness can be the largest influencers. Drought-ridden western-American states require additional and revised regulatory requirements to promote recycled water in new development. Currently, water reuse is largely used for agricultural and industrial purposes. To motivate and encourage housing development, water recycling needs to …

Evaluation Of An Equivalent Mean Grain Size Diameter To Rationally Predict The Erodibility Of Fine Riverbed Soils In Nebraska, Basil Abualshar

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The erosion of riverbed soils under the bridges is one of the major reasons that cause bridge closure or failure leading to a significant effect on the local economy. One of the commonly used methods to predict the erosion rate of soils is the excess shear stress method, which is based on two parameters describing the erodibility behavior; the erodibility coefficient and the critical shear stress. On the other hand, studies showed that the mean grain size diameter D₅₀ could be correlated to the erosion resistance of soils, usually for cohesionless soils but not for cohesive soils. It is …