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Full-Text Articles in Engineering

Multi-Factor Optimization Of Bio-Methanol Production Through Gasification Process Via Statistical Methodology Coupled With Genetic Algorithm, Amin Hedayati Moghaddam, Morteza Esfandyari, Dariush Jafari, Hossein Sakhaeinia Oct 2023

Multi-Factor Optimization Of Bio-Methanol Production Through Gasification Process Via Statistical Methodology Coupled With Genetic Algorithm, Amin Hedayati Moghaddam, Morteza Esfandyari, Dariush Jafari, Hossein Sakhaeinia

Department of Civil and Environmental Engineering: Faculty Publications

This work innovatively explores the bio-methanol production process, conducts comprehensive analyses, develops statistical models, and optimizes operational conditions, contributing valuable insights to the field of sustainable energy production from biomass. Accordingly, bio-methanol production from biomass through gasification route was investigated and simulated using Aspen Plus software. The effects of operational parameters on energy duty of gasification reactor and the methanol production rate in syngas to methanol reactor were investigated. The parameters affecting the process performance including temperature, pressure, and steam/feed ratio were examined using the response surface methodology (RSM) by central composite design (CCD) technique. Analysis of variance (ANOVA) was …

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Multi-Factor Optimization Of Bio-Methanol Production Through Gasification Process Via Statistical Methodology Coupled With Genetic Algorithm, Amin Hedayati Moghaddam, Morteza Esfandyari, Dariush Jafari, Hossein Sakhaeinia Oct 2023

Multi-Factor Optimization Of Bio-Methanol Production Through Gasification Process Via Statistical Methodology Coupled With Genetic Algorithm, Amin Hedayati Moghaddam, Morteza Esfandyari, Dariush Jafari, Hossein Sakhaeinia

Department of Civil and Environmental Engineering: Faculty Publications

This work innovatively explores the bio-methanol production process, conducts comprehensive analyses, develops statistical models, and optimizes operational conditions, contributing valuable insights to the field of sustainable energy production from biomass. Accordingly, bio-methanol production from biomass through gasification route was investigated and simulated using Aspen Plus software. The effects of operational parameters on energy duty of gasification reactor and the methanol production rate in syngas to methanol reactor were investigated. The parameters affecting the process performance including temperature, pressure, and steam/feed ratio were examined using the response surface methodology (RSM) by central composite design (CCD) technique. Analysis of variance (ANOVA) was …

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Rilem Tc 266-Mrp: Round-Robin Rheological Tests On High Performance Mortar And Concrete With Adapted Rheology—Evaluating Structural Build-Up At Rest Of Mortar And Concrete, Sofiane Amziane, Kamal Khayat, Mohammed Sonebi, Arnaud Perrot Oct 2023

Rilem Tc 266-Mrp: Round-Robin Rheological Tests On High Performance Mortar And Concrete With Adapted Rheology—Evaluating Structural Build-Up At Rest Of Mortar And Concrete, Sofiane Amziane, Kamal Khayat, Mohammed Sonebi, Arnaud Perrot

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This Paper Presents the Results of a Round-Robin Testing Program Undertaken by RILEM TC-266-Measuring Rheological Properties of Cement-Based Materials in May 2018 at the Université D'Artois in Bethune, France. Seven Types of Rheometers Were Compared; They Consisted of Four ICAR Rheometers, Viskomat XL Rheometer, EBT-V Rheometer, Sliding Pipe Rheometer (SLIPER), RheoCAD Rheometer, and 4SCC Rheometer, as Well as the Plate Test. This Paper Discusses the Results of the Evolution of the Static Yield Stress at Rest of Three Mortar and Five Concrete Mixtures that Were Determined using Two ICAR Rheometers, Viskomat XL, and EBT-V Rheometers, as Well as the Plate …

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Effect Of Rotation On Mixing Efficiency In Homogeneous Stratified Turbulence Using Unforced Direct Numerical Simulations, Matthew Klema, S. Karan Venayagamoorthy, Annick Pouquet, Duane Rosenberg, Raffaele Marino Oct 2023

Effect Of Rotation On Mixing Efficiency In Homogeneous Stratified Turbulence Using Unforced Direct Numerical Simulations, Matthew Klema, S. Karan Venayagamoorthy, Annick Pouquet, Duane Rosenberg, Raffaele Marino

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Diapycnal (irreversible) mixing is analyzed using thirty direct numerical simulations (at 1024 3 resolution) of homogeneous rotating stratified turbulence (RST) in the absence of imposed shear or forcing. The influence of varied rotation and stratification rates on the energetics (in particular the dissipation rates of kinetic and potential energies) is presented. Data is also analyzed within a new parametric framework, using the turbulent Froude and Rossby numbers Frt= ϵ/ Nk, Rot= ϵ/ fk, where k is the turbulent kinetic energy, ϵ its rate of dissipation, N the buoyancy frequency and f the Coriolis parameter. This framework is used to illustrate …

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Preface: Special Issue On Turbulence And Mixing In Stratified Flows, S. Karan Venayagamoorthy Oct 2023

Preface: Special Issue On Turbulence And Mixing In Stratified Flows, S. Karan Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

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Mixing Rates In Stably Stratified Flows With Respect To The Turbulent Froude Number And Turbulent Scales, Matthew R. Klema, Subhas Karan Venayagamoorthy Oct 2023

Mixing Rates In Stably Stratified Flows With Respect To The Turbulent Froude Number And Turbulent Scales, Matthew R. Klema, Subhas Karan Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this analysis the quantification of diapycnal diffusivity Kρ in stratified flows such as those found in the ocean and atmosphere is explored. There are two simplifications that are routinely made when estimating mixing rates in stably stratified flows. First, a constant value is commonly assumed for the (irreversible) mixing coefficient Γ . Second, dissipation rates of turbulent kinetic energy ϵ are inferred using either the Thorpe (or Ellison) length scales or from microstructure measurements using the isotropy assumption. Data from three independent direct numerical simulations of homogeneous stratified turbulence are used as a testbed to highlight impacts of these …

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System Dynamic Modeling To Study The Impact Of Construction Industry Characteristics And Associated Macroeconomic Indicators On Workforce Size And Labor Retention Rate, Tamima Elbashbishy, Islam H. El-Adaway Oct 2023

System Dynamic Modeling To Study The Impact Of Construction Industry Characteristics And Associated Macroeconomic Indicators On Workforce Size And Labor Retention Rate, Tamima Elbashbishy, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Limited skilled labor has been one of the greatest challenges facing the construction industry. The COVID-19 pandemic has further exaggerated the already strained construction labor market, leading to an additional negative impact. One of the major contributors to skilled labor shortages in construction is the issue of labor retention. Overall, this is a complex and dynamic situation that requires effective and efficient simulation-based techniques to capture the interdependent relationships that affect the performance of the construction labor market. This paper fills this knowledge gap. To this end, the authors used a multistep research methodology that involved (1) identifying factors that …

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Atomic Insights Into The Structural Properties And Displacement Cascades In Ytterbium Titanate Pyrochlore (Yb2ti2o7) And High-Entropy Pyrochlores, M. Mustafa Azeem, Qingyu Wang Oct 2023

Atomic Insights Into The Structural Properties And Displacement Cascades In Ytterbium Titanate Pyrochlore (Yb2ti2o7) And High-Entropy Pyrochlores, M. Mustafa Azeem, Qingyu Wang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Pyrochlore oxides ((Formula presented.) are potential nuclear waste substrate materials due to their superior radiation resistance properties. We performed molecular dynamics simulations to study the structural properties and displacement cascades in ytterbium titanate pyrochlore ((Formula presented.)) and high-entropy alloys (HEPy), e.g., (Formula presented.), (Formula presented.), and (Formula presented.). We computed lattice constants (LC) ((Formula presented.)) and threshold displacement energy (Ed). Furthermore, the calculation for (Formula presented.) and ionic radius ((Formula presented.)) were performed by substituting a combination of cations at the A and B sites of the original pyrochlore structure. Our simulation results have demonstrated that the lattice constant is …

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Mechanism Underlying Effect Of Expansive Agent And Shrinkage Reducing Admixture On Mechanical Properties And Fiber-Matrix Bonding Of Fiber-Reinforced Mortar, Kamran Aghaee, Taihao Han, Aditya Kumar, Kamal Khayat Oct 2023

Mechanism Underlying Effect Of Expansive Agent And Shrinkage Reducing Admixture On Mechanical Properties And Fiber-Matrix Bonding Of Fiber-Reinforced Mortar, Kamran Aghaee, Taihao Han, Aditya Kumar, Kamal Khayat

Materials Science and Engineering Faculty Research & Creative Works

Expansive agent (EA) and shrinkage reducing admixture (SRA) are utilized to reduce shrinkage and risk of cracking in concrete. EA compensates shrinkage by initial expansion, and SRA reduces surface tension in the pore fluid. Although EA and SRA effectively reduce shrinkage, they can impair micro-structure of concrete at high contents. The shrinkage reduction effect of EA and SRA is well known; however, there is limited knowledge about their negative effect on microstructure and fiber matrix interfacial transition zone (ITZ). The current study explores the effect of using 10 % CaO-based EA, 2 % SRA, and their combination on mechanical, shrinkage, …

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2023 Final Report For Databases In The 2022 Traffic Records Improvement Plan: Facilitating The Development Of Projects To Attain The Goals In The Implementation Plan For The 2022-26 Traffic Records Strategic Plan, Lenahan O'Connell, Samantha Wright, Reginald Souleyrette Oct 2023

2023 Final Report For Databases In The 2022 Traffic Records Improvement Plan: Facilitating The Development Of Projects To Attain The Goals In The Implementation Plan For The 2022-26 Traffic Records Strategic Plan, Lenahan O'Connell, Samantha Wright, Reginald Souleyrette

Kentucky Transportation Center Research Report

During fiscal year 2023, with financial support (Grant #M3Da-2022-04) from the Kentucky Office of Highway Safety, the Kentucky Transportation Center (KTC)-continued its work with traffic database officials to facilitate successful attainment of the remaining goals from the 2017-21 Traffic Records Strategic Plan (TRSP), which goals are in the 2022-26 TRSP Transportation Records Improvement Plan (TRIP). For most databases, some new goals were developed; this required further refinement of some projects or strategies to improve database performance. Projects to complete the goals in the TRIP were continued and some completed for the following databases: CRASH, Citation/Adjudication, Injury Surveillance (KIPRC and EMS), …

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Additive Manufacturing And Characterization Of Auxetic Structures, Jayesh P. Moore, Stephanie R. Ruzicka Oct 2023

Additive Manufacturing And Characterization Of Auxetic Structures, Jayesh P. Moore, Stephanie R. Ruzicka

College of Engineering Summer Undergraduate Research Program

An auxetic structure is an arrangement of unit cells that under a uniaxial load experiences expansion in both the longitudinal and transverse directions, resulting in a negative Poisson’s ratio (NPR). Research in auxetics has led to new insights into how non-linear mechanical reactions can be applied to various engineering fields. This project utilized stereolithography (SLA) 3D printing to manufacture auxetic test specimens to analyze of geometry-driven NPRs. With the distinctive mechanical properties of auxetic structures and vast applications, the future of product development of these geometries seems promising.

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Erosion Resistant Rock Shoulder, Chung R. Song, Richard L. Wood, Basil Abualshar, Mark O'Brien, Bashar Al-Nimri, Mitra Nasimi Oct 2023

Erosion Resistant Rock Shoulder, Chung R. Song, Richard L. Wood, Basil Abualshar, Mark O'Brien, Bashar Al-Nimri, Mitra Nasimi

Nebraska Department of Transportation: Research Reports

Highway shoulder rocks are exposed to continuous erosion force due to unexpected floodings caused by climate change. The evaluation methods of the erosion resistance of highway shoulder rocks are not currently well-developed. This study developed a new large-scale testing device, the University of Nebraska-Lincoln Erosion Testing Bed (UNLETB), which has the capability of testing the shoulder gravels. Different gradations were tested using UNLETB, and the results distinguished a high-resistant group and a low-resistant group. The low resistant group was treated with different binding agents: Ammonium Lignosulfonate (LIGNO10), Soybean Soap Stock, and DirtGlue. The treated samples showed better erosion resistance based …

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Unhsc Street Sweeping Credit Calculator, Unh Stormwater Center Oct 2023

Unhsc Street Sweeping Credit Calculator, Unh Stormwater Center

UNH Stormwater Center

No abstract provided.

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The Role Of Membrane Porosity In Ion Removal By Ro/Nf Membranes And Development Of A Regenerable Pac-Loaded Membrane, Yizhi Hou Oct 2023

The Role Of Membrane Porosity In Ion Removal By Ro/Nf Membranes And Development Of A Regenerable Pac-Loaded Membrane, Yizhi Hou

Dissertations (1934 -)

Reverse osmosis (RO) and nanofiltration (NF) membranes are widely used for water treatment applications. They are charged porous materials, in which size exclusion and charge exclusion work together to dictate solute transport. In this study, membrane porosity was primarily determined by pore size. Thicker, more porous membranes with smaller pores had higher NaCl removal and less permeate water flux. Higher porosity membranes have greater inner pore surface area available to support a greater number of functional groups, thereby rejecting ion flux and increasing ion removal. The Donnan steric pore model (DSPM) was used to determine that the contribution of diffusion …

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Lithium Extraction From Aqueous Solution Using Magnesium Doped Lithium Ion-Sieve Composite, Ujjwal Pokharel Oct 2023

Lithium Extraction From Aqueous Solution Using Magnesium Doped Lithium Ion-Sieve Composite, Ujjwal Pokharel

Civil & Environmental Engineering Theses & Dissertations

This study focused on the development of a magnesium doped ion-sieve composite to extract lithium from an aqueous solution using adsorption process. The extraction process will provide a sustainable alternative to the currently practiced solar evaporation/concentration method which is very slow (takes 24 months) and water intensive. Currently, most of the lithium in the world comes from the mining of lithium or from the evaporative extraction process from the brine. Additionally, the Salton Sea area geothermal brines are recognized as potentially important domestic sources of lithium. Lithium concentration in geothermal brines from the Salton Sea area is reported to be …

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An Effective Model For Dynamic Properties Of Local Soils And Their Influence On Seismic Response Of A Typical Reinforced Concrete Building, Kaveh Zehtab Oct 2023

An Effective Model For Dynamic Properties Of Local Soils And Their Influence On Seismic Response Of A Typical Reinforced Concrete Building, Kaveh Zehtab

Civil & Environmental Engineering Theses & Dissertations

This dissertation presents an effective model to determine the dynamic properties of local soils and their impact on the seismic response of a typical mid-height reinforced concrete building. The results of the study suggest that the use of global models and empirical relationships for the dynamic properties of soils may not consider the effects of unique stress conditions on the cyclic response of the foundation soil. The study also investigates the seismic response of a site in central Adapazarı, Turkey, where four- to seven-story buildings suffered significant damage during the 1999 Kocaeli earthquake. A new model is presented that combines …

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Load Determination, Strengthening, And Behavior Study Of Prestressed Concrete Channel Bridge Girders In South Carolina, Elhussien Khaled Elbatanouny Oct 2023

Load Determination, Strengthening, And Behavior Study Of Prestressed Concrete Channel Bridge Girders In South Carolina, Elhussien Khaled Elbatanouny

Theses and Dissertations

The South Carolina Department of Transportation (SCDOT) is currently engaged in a multi-year effort to assess the structural integrity of its inventory of over 9,000 bridges. This assessment process is expected to result in an increase in the number of bridges that require load postings, repairs, or replacements across South Carolina. This could potentially lead to adverse economic repercussions due to restricted truck routes, bridge closures, repair work, and the need for bridge replacements. To alleviate the escalating costs associated with these challenges, it is imperative to explore methods aimed at reducing the need for load postings and bridge closures …

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Upscaling Wetland Methane Emissions From The Fluxnet-Ch4 Eddy Covariance Network (Upch4 V1.0): Model Development, Network Assessment, And Budget Comparison, Gavin Mcnicol, Etienne Fluet-Chouinard, Zutao Ouyang, Sara Knox, Zhen Zhang, Tuula Aalto, Sheel Bansal, Kuang Yu Chang, Min Chen, Kyle Delwiche, Sarah Feron, Mathias Goeckede, Jinxun Liu, Avni Malhotra, Joe R. Melton, William Riley, Rodrigo Vargas, Kunxiaojia Yuan, Qing Ying, Qing Zhu, Pavel Alekseychik, Mika Aurela, David Billesbach, David I. Campbell, Jiquan Chen, Housen Chu, Ankur R. Desai, Eugenie Euskirchen, Jordan Goodrich, Timothy Griffis, Manuel Helbig, Takashi Hirano, Hiroki Iwata, Gerald Jurasinski, John King, Franziska Koebsch, Randall Kolka, Ken Krauss, Annalea Lohila, Ivan Mammarella Oct 2023

Upscaling Wetland Methane Emissions From The Fluxnet-Ch4 Eddy Covariance Network (Upch4 V1.0): Model Development, Network Assessment, And Budget Comparison, Gavin Mcnicol, Etienne Fluet-Chouinard, Zutao Ouyang, Sara Knox, Zhen Zhang, Tuula Aalto, Sheel Bansal, Kuang Yu Chang, Min Chen, Kyle Delwiche, Sarah Feron, Mathias Goeckede, Jinxun Liu, Avni Malhotra, Joe R. Melton, William Riley, Rodrigo Vargas, Kunxiaojia Yuan, Qing Ying, Qing Zhu, Pavel Alekseychik, Mika Aurela, David Billesbach, David I. Campbell, Jiquan Chen, Housen Chu, Ankur R. Desai, Eugenie Euskirchen, Jordan Goodrich, Timothy Griffis, Manuel Helbig, Takashi Hirano, Hiroki Iwata, Gerald Jurasinski, John King, Franziska Koebsch, Randall Kolka, Ken Krauss, Annalea Lohila, Ivan Mammarella

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Wetlands are responsible for 20%–31% of global methane (CH4) emissions and account for a large source of uncertainty in the global CH4 budget. Data-driven upscaling of CH4 fluxes from eddy covariance measurements can provide new and independent bottom-up estimates of wetland CH4 emissions. Here, we develop a six-predictor random forest upscaling model (UpCH4), trained on 119 site-years of eddy covariance CH4 flux data from 43 freshwater wetland sites in the FLUXNET-CH4 Community Product. Network patterns in site-level annual means and mean seasonal cycles of CH4 fluxes were reproduced accurately in tundra, boreal, and temperate regions (Nash-Sutcliffe Efficiency ∼0.52–0.63 and 0.53). …

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Localization And Shape Determination Of A Hidden Corridor In The Great Pyramid Of Giza Using Non-Destructive Testing, Mohamed Elkarmoty, Johannes Rupfle, Khalid Helal, Mohamed Sholqamy, Mohamed Fath-Elbab, Jochen Kollofrath, Thomas Schumacher, Multiple Additional Authors Oct 2023

Localization And Shape Determination Of A Hidden Corridor In The Great Pyramid Of Giza Using Non-Destructive Testing, Mohamed Elkarmoty, Johannes Rupfle, Khalid Helal, Mohamed Sholqamy, Mohamed Fath-Elbab, Jochen Kollofrath, Thomas Schumacher, Multiple Additional Authors

Civil and Environmental Engineering Faculty Publications and Presentations

Built over 4500 years ago, the Great Pyramid of Giza, Egypt, is the only remaining structure of the Wonders of the Ancient World as described by the ancient Greek historian Herodotus. Despite this long existence, only recently has modern science and technology been employed to study this massive stone structure. Cosmic-ray muon radiography throughout the ScanPyramids project has detected a large void above the Grand Gallery of the Great Pyramid and a smaller unidentified void behind the so-called Chevron. The Chevron is an assembly of four large limestone blocks arranged in the shape of two inverted downward open angles. Guided …

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Construction Aspects And Seismic Analysis Of Typical Buildings In Dolpo, Lhakpa Tsering Oct 2023

Construction Aspects And Seismic Analysis Of Typical Buildings In Dolpo, Lhakpa Tsering

Independent Study Project (ISP) Collection

This study delves into the construction aspects and seismic analysis of typical buildings in the challenging terrain of Dolpo, situated within the Himalayan mountain range. Dolpo's unique geological and geographical characteristics, combined with its susceptibility to seismic activity, make it crucial to investigate and understand the dynamics of construction in this remote region. The research explores traditional and contemporary building practices, aiming to elucidate the interplay between construction methodologies and seismic resilience. Through a comprehensive examination of the geological context, structural design, and seismic vulnerability, this study contributes valuable insights to inform the development of robust and earthquake-resistant building strategies …

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Harnessing Surrogate Modeling And Machine Learning For Management Of Water Resources And Environmental Systems, Mahdi Erfani Oct 2023

Harnessing Surrogate Modeling And Machine Learning For Management Of Water Resources And Environmental Systems, Mahdi Erfani

Theses and Dissertations

In a world characterized by increasing and more frequent climate extreme events, population growth, and limited opportunities for infrastructural expansion, the imperative for more efficient and resilient planning, design, and operation of water resources and environmental systems has never been more apparent. Moreover, the emergence of high-dimensional data and the demand for quick and informed decision-making have created a critical challenge for the operation and management of these systems. To address these issues effectively, the ability to rapidly grasp and accelerate the analysis of this data is paramount, and this necessitates the innovative use of machine learning and surrogate modeling …

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Field And Laboratory Characterization Of Subgrade Resilient Modulus For The Aashtoware Pavement Me, Kazi Moninul Islam Oct 2023

Field And Laboratory Characterization Of Subgrade Resilient Modulus For The Aashtoware Pavement Me, Kazi Moninul Islam

Theses and Dissertations

The new Mechanistic-Empirical Pavement Design Guide (MEPDG) uses the subgrade resilient modulus (MR) as the key input parameter to represent the subgrade soil behavior for pavement design. This research focused on field and laboratory characterization of subgrade resilient modulus assessing the effects of predicted distresses and IRI on the flexible pavement. The results of this study are presented in the form of three chapters and peer-reviewed journal manuscripts. Firstly (Chapter 3), MR was obtained indirectly from Falling Weight Deflectometer (FWD) data using a back-calculation tool (i.e., SCDOT, BAKFAA, and AASHTOWare 2017) or from empirical correlations with soil index properties. MR …

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Evaluation Of The Dynamic Response Of Gravelly Soil Under Different Drainage Conditions, Pressley Margaret Perry Oct 2023

Evaluation Of The Dynamic Response Of Gravelly Soil Under Different Drainage Conditions, Pressley Margaret Perry

Theses and Dissertations

Throughout history in the field of geotechnical earthquake engineering, there have been numerous experimental investigations on the dynamic behavior of soils. Many of these efforts have been focused on sand and silty sand material due to their susceptibility to liquefaction phenomena. However, gravelly soil material (i.e., soil in which gradation contains primarily gravel and sand) has exhibited this phenomenon in response to earthquake loading in many case histories. Therefore, it is important to extend the experimental assessment of gravelly soil material to develop a better understanding of the cyclic response and to support the development of numerical models. This study …

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Investigation Of Discrepancies In South Carolina Traffic Collision Forms, Jackson Wegmet Oct 2023

Investigation Of Discrepancies In South Carolina Traffic Collision Forms, Jackson Wegmet

Theses and Dissertations

The aim of this thesis is to improve the accuracy of information recorded in the South Carolina traffic collision forms. To accomplish this, it examines 200 forms containing information about fatal crashes in work zones between 2014 and 2020 to determine how many discrepancies exist between the written narrative and other fields. In addition to obtaining these statistics, this thesis seeks to identify factors that influence discrepancies. To test the hypothesis that crash complexity and weather influence the investigating officer’s level of processing (a theory developed by Craik and Lockhart in 1972), and consequentially his/her ability to complete the traffic …

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The Professional Constructor, Full Issue, Volume 48, Number 01 Oct 2023

The Professional Constructor, Full Issue, Volume 48, Number 01

The Professional Constructor

No abstract provided.

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Channel Morphology Of A Leaky Coastal Plain River: The Congaree River, Sc 1884-2022, William Nicholas Logan Oct 2023

Channel Morphology Of A Leaky Coastal Plain River: The Congaree River, Sc 1884-2022, William Nicholas Logan

Theses and Dissertations

Downstream changes in river planform can be associated with changes in geologic controls and often signal changes in channel geometry, bed slope, or bed material grain size. While previous studies documented downstream trends in channel geometry and planform for a variety of rivers, there is a gap in the literature on spatial and temporal trends in channel geometry on the fluvial part of Coastal Plain rivers, i.e., the not-tidally influenced part. The literature highlights the existence of crevasse splays in natural levees that allow floodplain inundation below bankfull conditions as unique feature of channels and floodplains in the Coastal Plain. …

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Floodplain And In-Channel Sedimentation In The Bedrock Congaree River, Sc, Mahsa Ahmadpoor Oct 2023

Floodplain And In-Channel Sedimentation In The Bedrock Congaree River, Sc, Mahsa Ahmadpoor

Theses and Dissertations

The Congaree River planform is characterized by an abrupt increase in channel sinuosity in the downstream direction. Such a change is not typical of alluvial meandering rivers but has been observed in mixed bedrock-alluvial rivers. This motivated the first study of this dissertation, specifically designed to determine if the Congaree River is indeed a mixed bedrock-alluvial river in its low sinuosity (upstream) reach. To test this hypothesis, sonar-based measurements of channel bed and sublayer elevation were performed from Columbia to the Congaree River-Wateree River confluence. The sublayer is here defined as the first surface visible in the sonar measurements underneath …

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Electric Freight Transportation System Planning And Truck Operation Optimizations, Xuanke Wu Oct 2023

Electric Freight Transportation System Planning And Truck Operation Optimizations, Xuanke Wu

Theses and Dissertations

The substantial demand for fossil fuel consumption is a significant contributor to greenhouse gas emissions, drawing considerable public attention to health and environmental problems. As a result, vehicle electrification is currently recognized as the most effective approach to reduce CO2 emissions from transportation. However, compared to traditional fossil fuel-powered vehicles, electric vehicles have notable disadvantages, including higher upfront purchasing price, longer recharging time, and most significantly, lower driving ranges. All these challenges can potentially result in increased overall operational costs for logistics companies. This thesis proposes a comprehensive optimization modeling framework for electric freight transportation system planning and operations with …

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Virus Control Aboard A Commuter Bus, Hamid Rahai, Jeremy Bonifacio Oct 2023

Virus Control Aboard A Commuter Bus, Hamid Rahai, Jeremy Bonifacio

Mineta Transportation Institute

A major health concern for public transit users is exposure to viruses from other passengers. This numerical study examines virus containment aboard a public bus with changes to the bus ventilation system. The virus was modeled as a 2.5 µm round solid particle released from the mouth of the infectious passenger at a rate of 21 particles per second at a mouth velocity of 0.278 m/sec. The air delivery to the cabin was two linear ceiling slots spanning the length of the bus delivering 59.38 m3/min (2,097 CFM) of air at a mean velocity of 1 m/sec. Two different axial …

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Investigating The Impact Of Seawater Intrusion On The Operation Cost Of Groundwater Supply In Island Aquifers, Weijiang Yu, Domenico Baù, Alex S. Mayer, Lauren K. Mancewicz, Mohammadali Geranmehr Oct 2023

Investigating The Impact Of Seawater Intrusion On The Operation Cost Of Groundwater Supply In Island Aquifers, Weijiang Yu, Domenico Baù, Alex S. Mayer, Lauren K. Mancewicz, Mohammadali Geranmehr

Michigan Tech Publications

Managing fragile island freshwater resources requires identifying pumping strategies that trade off the financial cost of groundwater supply against controlling the seawater intrusion (SWI) associated with aquifer pumping. In this work, these tradeoffs are investigated through a sensitivity analysis conducted in the context of an optimization formulation of the groundwater management problem, which aims at minimizing the groundwater supply operation cost associated with groundwater pumping and desalination treatment, subject to constraints on SWI control, as quantified by the water table drawdown over the well (∆s), the reduction in freshwater volume (∆FV) in the aquifer, or the salt mass increase (∆SM) …

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