Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

University of Texas at Arlington

Series

Discipline
Keyword
Publication Year
Publication
File Type

Articles 1 - 30 of 134

Full-Text Articles in Engineering

Randomly Generated Non-Negative Linear Programs, Jay Rosenberger Jul 2024

Randomly Generated Non-Negative Linear Programs, Jay Rosenberger

Industrial, Manufacturing, and Systems Engineering Datasets

This dataset include randomly generated non-negative linear programs that appears in several papers on Constraint Optimal Selection Techniques (COSTs) for Linear Programming.


Design, Prototyping, And Characterization Of A Micro-Force Sensor Intended For Tissue Assessment In Confined Spaces, Shashank S. Kumat, Panos S. Shiakolas Jun 2024

Design, Prototyping, And Characterization Of A Micro-Force Sensor Intended For Tissue Assessment In Confined Spaces, Shashank S. Kumat, Panos S. Shiakolas

Open Initiatives Grant Funded Publications

The quantitative characterization of soft tissue viscoelastic properties can aid in disease prognosis and diagnosis. Existing technologies present challenges to measuring localized in vivo tissue relaxation data while meeting load and geometric constraints. This research presents the design, prototype, and characterization of a micro-force sensor that could enable better access to confined spaces of the human body. The novel design of the uniaxial micro-force sensor has an external diameter of less than or equal to 3.5 mm and 1 N load capacity for transurethral palpation of the bladder interior wall. The conceptual design of the micro-force sensor and a finite …


Navigate The World Of Rfid: Diversity, Capabilities, And Constraints Of Readers And Tags, Rachana Pandey May 2024

Navigate The World Of Rfid: Diversity, Capabilities, And Constraints Of Readers And Tags, Rachana Pandey

2024 Spring Honors Capstone Projects

Radio-Frequency Identification (RFID) technology, a method for storing and retrieving data through electromagnetic transmission to an RFID tag, is revolutionizing inventory and asset management in various sectors, including healthcare. This research explores the applications of RFID in a medical setting. It assesses various RFID readers and tags, focusing on their functional capabilities, ranges, and limitations within a medical environment. Employing a comprehensive approach, the study integrates an extensive literature review, comparative analysis, and empirical data from both experimental simulations and real-world healthcare scenarios. The aim is to identify RFID solutions that optimize surgical equipment management, thereby enhancing both operational efficiency …


An Assessment Of Methane Cracking Technologies For Hydrogen Production And Reduction Of Greenhouse Gases, Alisa E. Pjetrovic May 2024

An Assessment Of Methane Cracking Technologies For Hydrogen Production And Reduction Of Greenhouse Gases, Alisa E. Pjetrovic

2024 Spring Honors Capstone Projects

Methane reformation and methane pyrolysis involve separating, or cracking, the components of methane, leading to the production of hydrogen gas, and in the case of pyrolysis, solid carbon. Because methane is known as a leading cause of climate change, these technologies are gaining attention as the global community moves to address methane as a greenhouse gas. This study aims to assess, through a systematic literature review, the current state-of-the-art methane cracking technologies based on seven technology criteria: hydrogen production capability, environmental impact, value of carbon produced, reaction stability, operating temperature requirements, energy requirements, and Technology Readiness Level (TRL). This study …


Investigating Rural Traffic Dynamics: A Traffic Study On E 2nd Street Intersection’S Behavior And Safety, Ma Anjelika Rose T. Pineda May 2024

Investigating Rural Traffic Dynamics: A Traffic Study On E 2nd Street Intersection’S Behavior And Safety, Ma Anjelika Rose T. Pineda

2024 Spring Honors Capstone Projects

Traffic studies guide engineers in designing road networks to ensure smooth traffic flow and public safety. Such studies assess the need for traffic control devices to manage vehicle flow safely and efficiently. This is crucial at intersections which pose high risks of collision and congestion. A traffic analysis at the intersection of Island Grove and E 2nd Street on the FM-4 roadway in Cleburne, TX was conducted to evaluate the sufficiency of the current traffic control device. TxDOT warrants and standards and a field study were utilized and performed to justify the substitution for a traffic signal at the intersection. …


Establishing Employee Sense Of Belonging In A Busy Work Environment, Zoe A. Rodriguez May 2024

Establishing Employee Sense Of Belonging In A Busy Work Environment, Zoe A. Rodriguez

2024 Spring Honors Capstone Projects

This honors thesis capstone project explores the concept of an employee’s sense of belonging within a busy work environment. A department within ABC Company faces operational challenges regarding their daily tasks. The Honors contribution addresses the comparison between the busy work environment at ABC Company and existing literature to provide scholarly-supported recommendations and mitigation strategies for ABC Company. Existing literature underscores the importance of understanding contributing influences on an employee’s sense of belonging within the workplace. The honors contribution adds value by closing the information gap within companies that operate under a busy work environment and strategies of how to …


Effectivity Analysis Of Recommendation Algorithm: A Comparative Study Of The Performance Of A Hybrid Model And An Individual Recommendation Algorithm, Saniah Safat May 2024

Effectivity Analysis Of Recommendation Algorithm: A Comparative Study Of The Performance Of A Hybrid Model And An Individual Recommendation Algorithm, Saniah Safat

2024 Spring Honors Capstone Projects

This study explores the effectiveness of a hybrid recommendation system for e-commerce by integrating content-based, collaborative, and popularity-based models. Traditional individual algorithms have inherent limitations, such as handling new users or items data sparsity and ensuring relevance and diversity in suggestions. The hybrid model seeks to overcome these challenges by leveraging the strengths of all three methods, thus potentially offering more precise, personalized product suggestions. The performance of each model and its integration into a hybrid system are evaluated through logistic regression analysis. Initial results indicate that the hybrid system significantly outperforms the individual models in terms of accuracy and …


Building A Wireless Electronic Control Unit For An Electric Vehicle, Hector S. Sosa May 2024

Building A Wireless Electronic Control Unit For An Electric Vehicle, Hector S. Sosa

2024 Spring Honors Capstone Projects

Modern vehicles have a variety of features such remote start systems, advance drive assist systems, smart suspension systems, and a feature rich infotainment system. With all this technology in the car, there exists a complex network of computers working together in conjunction to deliver the modern driving experience that many people have today. To be competitive in the market, auto manufacturers are tasked to add additional features to vehicles by adding additional or modifying electronic control units (ECUs). In this study, an ECU will be designed for a mock electric vehicle which contains an already established network of ECU’s. The …


Review: Implementation Of Video Documentation In Lessons Learned System In Construction, Jainil Patel May 2024

Review: Implementation Of Video Documentation In Lessons Learned System In Construction, Jainil Patel

2024 Spring Honors Capstone Projects

Organizations employ Lessons Learned Systems (LLS) to manage knowledge and capture valuable project experiences to improve future performance. However, the construction industry has yet to adopt such systems widely, presumably due to its sluggish tech integration and risk-prone characteristics. Of the numerous fragmented obstacles that impede LLS adoption, one noteworthy obstacle would be the challenge faced during the text documentation of experiences. Traditional text inputs are labor-intensive and time- consuming. Hence, video documentation can be a more efficient replacement with its quick and modern recording features. The technological advancement and the preference shift of younger generations from text to video …


Citdet, Jordan A. James, Heather K. Manching, Matthew R. Mattia, Kim D. Bowman, Amanda M. Hulse-Kemp, William J. Beksi Apr 2024

Citdet, Jordan A. James, Heather K. Manching, Matthew R. Mattia, Kim D. Bowman, Amanda M. Hulse-Kemp, William J. Beksi

Computer Science and Engineering Datasets

The CitDet dataset is composed of images captured at the USDA Agricultural Research Service Subtropical Insects and Horticulture Research Unit in Fort Pierce, FL, USA. Data was collected between October 2021 and October 2022. 579 images were captured from different sections of the orchard using the open-source application Field Book on Android tablets. While collecting images, we faced the camera in a portrait orientation directly centered on the tree of interest. All images were taken at the edge of the soil in the tree row to simulate a ground-based robot imaging the tree while moving between two rows of trees. …


Design And Implementation Of A Behavioral Sequence Framework For Human-Robot Interaction Utilizing Brain-Computer Interface And Haptic Feedback, Sudip Hazra, Shane Whitaker, Panos S. Shiakolas May 2023

Design And Implementation Of A Behavioral Sequence Framework For Human-Robot Interaction Utilizing Brain-Computer Interface And Haptic Feedback, Sudip Hazra, Shane Whitaker, Panos S. Shiakolas

Mechanical and Aerospace Student Research

In assistive robotics, research in Brain Computer Interface aims to understand human intent to enhance Human- Robot Interaction and augment human performance. In this research, a framework to enable a person with an upper limb disability to use an assistive system towards maintaining self-reliance is introduced and its implementation and evaluation are discussed. The framework interlinks functional components and establishes a behavioral sequence to operate the assistive system in three stages; action classification, verification, and execution. An action is classified based on identified human intent and verified through haptic and/or visual feedback before execution. The human intent is conveyed through …


Carbon Fibers Recycling From Degraded Prepregs And Mechanical Properties Or Recycled Composite, Monjur Morshed Rabby, Minhazur Rahman, Partha Pratim Das, Vamsee Vadlamudi, Rassel Raihan Apr 2023

Carbon Fibers Recycling From Degraded Prepregs And Mechanical Properties Or Recycled Composite, Monjur Morshed Rabby, Minhazur Rahman, Partha Pratim Das, Vamsee Vadlamudi, Rassel Raihan

Institute of Predictive Performance Methodologies (IPPM-UTARI)

The size of the global composites market is anticipated to grow more than previously. Due to the rapidly rising volume of CFRP production, the waste from this material poses numerous problems and has significantly increased the socio-technological pressure to find sustainable composite recycling solutions. The problem is that recycling the composite part is challenging once its service life has expired. The same problem is true for the raw materials (prepregs) used in composite manufacturing. When the prepreg out-life/shelf-life is over, prepregs are abandoned, resulting in a loss of millions of dollars and an adverse environmental effect. In this study, the …


On The Development And Evaluation Of A Framework For Brain-Computer Interface And Vibrotactile Feedback For Human-Robot-Interaction In Virtual Spaces And Robotic Hardware, Sudip Hazra, Shane Whitaker, Panos S. Shiakolas Feb 2023

On The Development And Evaluation Of A Framework For Brain-Computer Interface And Vibrotactile Feedback For Human-Robot-Interaction In Virtual Spaces And Robotic Hardware, Sudip Hazra, Shane Whitaker, Panos S. Shiakolas

Mechanical and Aerospace Student Research

Research in Brain-Computer Interface (BCI) aims to understand human intent with the goal to enhance Human-Robot Interaction (HRI) especially in the field of assistive robotics. The goal of this research is to develop a behavioral sequence based framework to help persons with upper limb disabilities to maintain self-dependence. The framework aims to operate in stages and links multiple functional components to identify human intent and control a robotic arm. The development, operation, and evaluation of the framework and the linked functional components to acquire, process, evaluate, and map BCI signals generated using facial expressions and head movements to predefined actions …


Artificial Intelligence Assisted Residual Strength And Life Prediction Of Fiber Reinforced Polymer Composites, Partha Pratim Das, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Rassel Raihan Jan 2023

Artificial Intelligence Assisted Residual Strength And Life Prediction Of Fiber Reinforced Polymer Composites, Partha Pratim Das, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Rassel Raihan

Institute of Predictive Performance Methodologies (IPPM-UTARI)

With the increased use of composite materials, researchers have developed many approaches for structural and prognostic health monitoring. Broadband Dielectric Spectroscopy (BbDS)/Impedance Spectroscopy (IS) is a state-of-the-art technology that can be used to identify and monitor the minute changes in damage initiation, accumulation, interactions, and the degree of damage in a composite under static and dynamic loading. This work presents a novel artificial neural network (ANN) framework for fiber-reinforced polymer (FRP) composites under fatigue loading, which incorporates dielectric state variables to predict the life (durability) and residual strength (damage tolerance) from real-time acquired dielectric permittivity of the material. The findings …


Supplementary Information For "Understanding Mid-To Large Underground Leaks From Buried Pipelines As Affected By Soil And Atmospheric Conditions – Field Scale Experimental Study", Navodi J.R.R. Jayarathne, Kathleen M. Smits, Stuart N. Riddick, Daniel J. Zimmerle, Younki Cho, Michelle Schwartz, Fancy Cheptonui, Kevan Cameron, Peter Ronney Aug 2022

Supplementary Information For "Understanding Mid-To Large Underground Leaks From Buried Pipelines As Affected By Soil And Atmospheric Conditions – Field Scale Experimental Study", Navodi J.R.R. Jayarathne, Kathleen M. Smits, Stuart N. Riddick, Daniel J. Zimmerle, Younki Cho, Michelle Schwartz, Fancy Cheptonui, Kevan Cameron, Peter Ronney

Earth & Environmental Sciences Datasets

Reducing the amount of leaked natural gas (NG) from pipelines from production to use has become a high priority in efforts to cut anthropogenic emissions of methane and ensure public safety. However, tracking and evaluating NG pipeline leaks, especially at moderate to high flow rates, requires a better understanding of the leak from the source to the detector as well as more robust quantification methods. To better understand fugitive emissions from NG pipelines, we developed a field scale testbed that simulates mid and high-pressure gas leaks from belowground natural gas infrastructure. The system is equipped with subsurface, surface and atmospheric …


Replication Data For: A Closer Look At Underground Natural Gas Pipeline Leaks Across The United States, Younki Cho, Kathleen M. Smits, Nathaniel L. Steadman, Bridget A. Ulrich, Clay S. Bell, Daniel J. Zimmerle Aug 2022

Replication Data For: A Closer Look At Underground Natural Gas Pipeline Leaks Across The United States, Younki Cho, Kathleen M. Smits, Nathaniel L. Steadman, Bridget A. Ulrich, Clay S. Bell, Daniel J. Zimmerle

Earth & Environmental Sciences Datasets

Underground natural gas (NG) pipeline leakage can result in methane (CH4) buildup and migration through the soil. What is not well understood in such scenarios is how the soil conditions affect the gas migration behavior, particularly in regard to the relative contributions of specific soil properties such as soil moisture content. The objective of this study was to investigate the effects of soil properties on CH4 concentration and migration from leaking underground NG pipelines. Site characteristics such as surface cover and spatial dimensions, soil samples, and gas concentration data were collected from over 70 gas leakage sites …


Replication Data For: Investigating Detection Probability Of Mobile Survey Solutions For Natural Gas Pipeline Leaks Under Different Atmospheric Conditions, Shanru Tian, Stuart Riddick, Younki Cho, Clay Bell, Daniel Zimmerle, Kathleen Smits Aug 2022

Replication Data For: Investigating Detection Probability Of Mobile Survey Solutions For Natural Gas Pipeline Leaks Under Different Atmospheric Conditions, Shanru Tian, Stuart Riddick, Younki Cho, Clay Bell, Daniel Zimmerle, Kathleen Smits

Earth & Environmental Sciences Datasets

The 2015 Paris agreement aims to cut greenhouse gas emissions and keep global temperature rise below 2 °C above pre-industrial levels. Reducing CH4 emissions from leaking pipelines presents a relatively achievable objective. While walking and driving surveys are commonly used to detect leaks, the detection probability (DP) is poorly characterized. This study aims to investigate how leak rates, survey distance and speed, and atmospheric conditions affect the DP in controlled belowground conditions with release rates of 0.5–8.5 g min−1. Results show that DP is highly influenced by survey speed, atmospheric stability, and wind speed. The average DP in Pasquill–Gifford stability …


Replication Data For "Estimating Methane Emissions From Underground Natural Gas Pipelines Using An Atmospheric Dispersion-Based Method", Shanru Tian, Kathleen M. Smits, Younki Cho, Stuart Riddick, Daniel Zimmerle, Aidan Duggan May 2022

Replication Data For "Estimating Methane Emissions From Underground Natural Gas Pipelines Using An Atmospheric Dispersion-Based Method", Shanru Tian, Kathleen M. Smits, Younki Cho, Stuart Riddick, Daniel Zimmerle, Aidan Duggan

Earth & Environmental Sciences Datasets

Methane (CH4) leakage from natural gas (NG) pipelines poses an environmental, safety, and economic threat to the public. While previous leak detection and quantification studies focus on the aboveground infrastructure, the analysis of underground NG pipeline leak scenarios is scarce. Furthermore, no data from controlled release experiments have been published on the accuracy of methods used to (1) quantify emissions from an area source and (2) use these emissions to quantify the size of a subsurface leak. This proof-of-concept work uses CH4 mole fraction, as measured by a single gas sensor, as an input to a simple …


Dielectric Analysis To Predict Moisture Absorption In Structural Composites: A Data-Driven Approach, Partha Pratim Das, Monjur Morshed Rabby, Vamsee Vadlamudi, Rassel Raihan Jan 2022

Dielectric Analysis To Predict Moisture Absorption In Structural Composites: A Data-Driven Approach, Partha Pratim Das, Monjur Morshed Rabby, Vamsee Vadlamudi, Rassel Raihan

Institute of Predictive Performance Methodologies (IPPM-UTARI)

Due to continual exposure to moist environment, environmental degradation is a major threat to structural composites throughout their service life. Impedance Spectroscopy (IS)/Broadband Dielectric Spectroscopy (BbDS) is a reliable nondestructive method that has been used in polymer industries for dielectric characterization of material. While moisture absorption causes irreversible changes in the polymer matrix composites, it also alters the electrical properties of the system which is detectable using BbDS. Since the physics that drives the change in electrical characteristics is driven by the modifications imposed by water molecules (whether free or bound), both events can be linked. A dielectric spectrum over …


Moisture Content Prediction In Polymer Composites Using Machine Learning Techniques, Partha Pratim Das, Monjur Morshed Rabby, Vamsee Vadlamudi, Rassel Raihan Jan 2022

Moisture Content Prediction In Polymer Composites Using Machine Learning Techniques, Partha Pratim Das, Monjur Morshed Rabby, Vamsee Vadlamudi, Rassel Raihan

Institute of Predictive Performance Methodologies (IPPM-UTARI)

The principal objective of this study is to employ non-destructive broadband dielectric spectroscopy/impedance spectroscopy and machine learning techniques to estimate the moisture content in FRP composites under hygrothermal aging. Here, classification and regression machine learning models that can accurately predict the current moisture saturation state are developed using the frequency domain dielectric response of the composite, in conjunction with the time domain hygrothermal aging effect. First, to categorize the composites based on the present state of the absorbed moisture supervised classification learning models (i.e., quadratic discriminant analysis (QDA), support vector machine (SVM), and artificial neural network-based multilayer perceptron (MLP) classifier) …


Coupled Effects In Dielectric And Thermal Properties Of Polymer Matrix Composite Structures Due To Moisture Absorption, Partha Pratim Das, Monjur Morshed Rabby, Vamsee Vadlamudi, Kenneth Reifsnider, Rassel Raihan Jan 2022

Coupled Effects In Dielectric And Thermal Properties Of Polymer Matrix Composite Structures Due To Moisture Absorption, Partha Pratim Das, Monjur Morshed Rabby, Vamsee Vadlamudi, Kenneth Reifsnider, Rassel Raihan

Institute of Predictive Performance Methodologies (IPPM-UTARI)

Fiber reinforced polymer (FRP) composites are being used in number of fields including aerospace, marine, sports, medical, power sectors, etc. due to their lightweight nature while retaining high mechanical performance in terms of high specific strength, stiffness, and great fatigue properties. However, the applicability of these materials is restricted by their stability up to a certain temperature (i.e. glass transition temperature) and environmental degradation (i.e. moisture, UV light, etc.). Moisture ingression greatly reduces their mechanical properties altering material structure by causing polymer plasticization, chain scission and fiber-polymer interface deterioration. These changes instantaneously affect the thermal properties of the materials which …


The Effect Of Plasma Treatment On The Cure Behavior Of Out-Of-Life Prepregs And An Investigation Of The Mechanical Properties Of Composite Parts Manufactured From Plasma-Treated Prepregs, Monjur Morshed Rabby, Partha Pratim Das, Minhazur Rahman, Vamsee Vadlamudi, Rassel Raihan Jan 2022

The Effect Of Plasma Treatment On The Cure Behavior Of Out-Of-Life Prepregs And An Investigation Of The Mechanical Properties Of Composite Parts Manufactured From Plasma-Treated Prepregs, Monjur Morshed Rabby, Partha Pratim Das, Minhazur Rahman, Vamsee Vadlamudi, Rassel Raihan

Institute of Predictive Performance Methodologies (IPPM-UTARI)

Many industries, including aircraft, automobiles, and marine, are using prepreg (pre-impregnated fibers and a partially cured polymer matrix) to manufacture composite parts to achieve optimum fiber and resin volume ratio and part repeatability. Since prepregs have a short out oflife (i.e., the maximum storing time allowed at room temperature), they must be stored in refrigerators at low temperatures, which, if not maintained, have an unfavorable influence on the intended quality of the final product. For the present study, glass/epoxy prepregs (expired out-life) were plasmatreated before being used to make the composite part to compensate for the room temperature aging effect. …


Dielectric State Variables As Qualitative Indicators Of Moisture Absorption-Caused Mechanical Property Degradation In Gfrp Composite Structures, Partha Pratim Das, Vamsee Vadlamudi, Rassel Raihan Jan 2022

Dielectric State Variables As Qualitative Indicators Of Moisture Absorption-Caused Mechanical Property Degradation In Gfrp Composite Structures, Partha Pratim Das, Vamsee Vadlamudi, Rassel Raihan

Institute of Predictive Performance Methodologies (IPPM-UTARI)

Fiber reinforced polymer (FRP) composites are being used in numerous fields owing to their intrinsic strength to weight ratio and various design benefits. However, these materials are prone to environmental aging, particularly moisture absorption. In essence, absorbed moisture infiltrates the polymer matrix and induces changes in the polymer network through chain scission, plasticization, and other bonding interactions. This causes irreversible damages to the material and significantly decreases mechanical strength. In this study, Broadband Dielectric Spectroscopy (BbDS) has been used to identify the absorption mechanisms in glass fiber reinforced polymer (GFRP) composites by detecting the related polarization mechanisms. Here, results show …


Replication Data For: Characterization Of Grain-Size Distribution, Thermal Conductivity, And Gas Diffusivity In Variably Saturated Binary Sand Mixtures, C. T.K.K. Deepagoda, Kathleen Smits Dec 2021

Replication Data For: Characterization Of Grain-Size Distribution, Thermal Conductivity, And Gas Diffusivity In Variably Saturated Binary Sand Mixtures, C. T.K.K. Deepagoda, Kathleen Smits

Earth & Environmental Sciences Datasets

Characterization of differently textured porous materials, as well as different volumetric porous media mixtures, in relation to mass and heat transport is vital for many engineering and research applications. Functional relations describing physical (e.g., grain-size distribution, total porosity), thermal, and gas diffusion properties of porous media and mixtures are necessary to optimize the design of porous systems that involve heat and gas transport processes. However, only a limited number of studies provide characterization of soil physical, thermal, and gas diffusion properties and the functional relationships of these properties under varying soil water contents, especially for soil mixtures, complicating optimization efforts. …


Replication Data For: Effect Of Varying Atmospheric Conditions On Methane Boundary-Layer Development In A Free Flow Domain Interfaced With A Porous Media Domain, C. T.K.K. Deepagoda, Kathleen Smits Dec 2021

Replication Data For: Effect Of Varying Atmospheric Conditions On Methane Boundary-Layer Development In A Free Flow Domain Interfaced With A Porous Media Domain, C. T.K.K. Deepagoda, Kathleen Smits

Earth & Environmental Sciences Datasets

Mitigation of atmospheric emission of methane from leaky underground infrastructure is important for controlling the global anthropogenic greenhouse gas burden. Overexposure to methane may also cause occupational health problems in indoor/outdoor environments at the local scale. Subsurface soil conditions (e.g. soil heterogeneity) affect methane migration in soils while near-surface atmospheric boundary conditions (e.g. wind and temperature) affect off-site emissions across the soil-atmosphere interface. This study investigated the above-surface methane concentration boundary-layer development under different soil conditions (homogenous and layered) and atmospheric boundary controls (wind and temperature). A series of controlled bench-scale experiments was conducted using an open-loop boundary-layer wind tunnel …


Replication Data For: Thermal Conductivity Of Binary Sand Mixtures Evaluated Through Full Water Content Range, Benjamin Wallen, Kathleen Smits Dec 2021

Replication Data For: Thermal Conductivity Of Binary Sand Mixtures Evaluated Through Full Water Content Range, Benjamin Wallen, Kathleen Smits

Earth & Environmental Sciences Datasets

A soil's grain-size distribution affects its physical and hydraulic properties; however, little is known about its effect on soil thermal properties. To better understand how grain-size distribution affects soil thermal properties, specifically the effective thermal conductivity, a set of laboratory experiments was performed using binary mixtures of two uniform sands tightly packed with seven different mixing fractions over the full range of saturation. For each binary mixture, the effective thermal conductivity, λ, capillary pressure, hc, and volumetric water content, θ, were measured. Results demonstrated that the λ–θ relationship exhibited distinct characteristics based on the percentage of fine- and coarse-grained sands. …


Replication Data For: Experimental And Numerical Study Of Evaporation From Wavy Surfaces By Coupling Free Flow And Porous Media Flow, Bo Gao, Kathleen Smits Dec 2021

Replication Data For: Experimental And Numerical Study Of Evaporation From Wavy Surfaces By Coupling Free Flow And Porous Media Flow, Bo Gao, Kathleen Smits

Earth & Environmental Sciences Datasets

The macroscale roughness of the soil surface has significant influences on the mass/energy interactions between the subsurface and the atmosphere during evaporation. However, most previous works only consider evaporation behavior from flat surfaces. Based on experimental and numerical approaches, the goal of this work is to provide a framework for the understanding of the mechanisms of evaporation from irregular soil surfaces at representative elementary volume scale. A coupling free flow-porous media flow model was developed to describe evaporation under nonisothermal conditions. For simplicity, sinusoidal-type wavy surfaces were considered. To validate this modeling approach, an experiment using an open-ended wind tunnel …


Replication Data For: Evaporation From Undulating Soil Surfaces Under Turbulent Airflow Through Numerical And Experimental Approaches, Bo Gao, Kathleen Smits, John Farnsworth Dec 2021

Replication Data For: Evaporation From Undulating Soil Surfaces Under Turbulent Airflow Through Numerical And Experimental Approaches, Bo Gao, Kathleen Smits, John Farnsworth

Earth & Environmental Sciences Datasets

Evaporation from undulating soil surfaces is rarely studied due to limited modeling theory and inadequate experimental data linking dynamic soil and atmospheric interactions. The goal of this paper is to provide exploratory insights into evaporation behavior from undulating soil surfaces under turbulent conditions through numerical and experimental approaches. A previously developed and verified coupled free flow and porous media flow model was extended by incorporating turbulent airflow through Reynolds-averaged Navier–Stokes equations. The model explicitly describes the relevant physical processes and the key properties in the free flow, porous media, and at the interface, allowing for the analysis of coupled exchange …


Replication Data For: Effect Of Subsurface Soil Moisture Variability And Atmospheric Conditions On Methane Gas Migration In Shallow Subsurface, C. T.K.K. Deepagoda, Kathleen Smits Oct 2021

Replication Data For: Effect Of Subsurface Soil Moisture Variability And Atmospheric Conditions On Methane Gas Migration In Shallow Subsurface, C. T.K.K. Deepagoda, Kathleen Smits

Earth & Environmental Sciences Datasets

A major concern resulting from the increased use and production of natural gas has been how to mitigate fugitive greenhouse gas emissions (predominantly methane) from natural gas infrastructure (e.g., leaky shallow pipelines). Subsurface migration and atmospheric loading of methane from pipeline leakage is controlled by source configurations and subsurface soil conditions (e.g., soil heterogeneity and soil moisture) and are further affected by atmospheric conditions (e.g., wind and temperature). However, the transport and attenuation of methane under varying subsurface and atmospheric conditions are poorly understood, making it difficult to estimate leakage fluxes from methane concentration measurements at and above the soil …


Replication Data For: Evaluation Of Model Concepts To Describe Water Transport In Shallow Subsurface Soil And Across The Soil–Air Interface, Zhen Li, Kathleen Smits Oct 2021

Replication Data For: Evaluation Of Model Concepts To Describe Water Transport In Shallow Subsurface Soil And Across The Soil–Air Interface, Zhen Li, Kathleen Smits

Earth & Environmental Sciences Datasets

Soil water evaporation plays a critical role in mass and energy exchanges across the land–atmosphere interface. Although much is known about this process, there is no agreement on the best modeling approaches to determine soil water evaporation due to the complexity of the numerical modeling scenarios and lack of experimental data available to validate such models. Existing studies show numerical and experimental discrepancies in the evaporation behavior and soil water distribution in soils at various scales, driving us to revisit the key process representation in subsurface soil. Therefore, the goal of this work is to test different mathematical formulations used …