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Full-Text Articles in Civil and Environmental Engineering

The Future Of Groundwater In California: Lessons In Sustainable Management From Across The West, Christina Hoffman Babbitt, Katherine E. B. Gibson, Scott Sellers, Nicholas Brozovic, Anthony Saracino, Ann Hayden, Maurice Hall, Sandi Zellmer Jan 2018

The Future Of Groundwater In California: Lessons In Sustainable Management From Across The West, Christina Hoffman Babbitt, Katherine E. B. Gibson, Scott Sellers, Nicholas Brozovic, Anthony Saracino, Ann Hayden, Maurice Hall, Sandi Zellmer

Daugherty Water for Food Global Institute: Faculty Publications

The 2014 Sustainable Groundwater Management Act (SGMA) created, for the first time and on an unprecedented scale, a mandate to change how groundwater is managed statewide in California. While enacting SGMA was a tremendous step forward, communities and water districts now face the considerable challenge of creating successful groundwater management programs. This report is aimed at helping California’s water managers, public water agencies, county commissioners, city planners, and others better understand the suite of tools and approaches that can be used to enhance the sustainable management of groundwater. Specifically, we consider four categories of management tools—regulatory, incentive-based, agency supply augmentation …


The Long Term Effect Of Agricultural, Vadose Zone And Climatic Factors On Nitrate Contamination In Nebraska’S Groundwater System, Pongpun Juntakut, Daniel D. Snow, Erin M.K. Haacker, Chittaranjan Ray Jan 2018

The Long Term Effect Of Agricultural, Vadose Zone And Climatic Factors On Nitrate Contamination In Nebraska’S Groundwater System, Pongpun Juntakut, Daniel D. Snow, Erin M.K. Haacker, Chittaranjan Ray

Nebraska Water Center: Faculty Publications

A four-decade dataset (1974–2013) of 107,823 nitrate samples in 25,993 wells from western and eastern parts of Nebraska was used to assess long-term trends of groundwater nitrate concentration and decadal changes in the extent of groundwater nitrate-contaminated areas (NO3-N≥10 mg N/L) over the entire state. Spatial statistics and regressions were used to investigate the relationships between groundwater nitrate concentrations and several potential natural and anthropogenic factors, including soil drainage capacities, vadose zone characteristics, crop production areas, and irrigation systems. The results of this study show that there is no statistically significant trend in groundwater nitrate concentrations …


Integrated Strategies For Sustainable Wastewater-Based Algal Biofuel Production And Environmental Mitigation In The Us, Javad Roostaei Jan 2018

Integrated Strategies For Sustainable Wastewater-Based Algal Biofuel Production And Environmental Mitigation In The Us, Javad Roostaei

Wayne State University Dissertations

Integration of algae cultivation with wastewater treatment has received increasing interest as a cost-effective strategy for biofuel production. However, there has been no full assessment of algal biofuel production with wastewater on macro-scale by taking into account wastewater resources, land availability, CO2 emission resources, and geographic variation. This research addressed and evaluated the use of wastewater for algae cultivation, in terms of modeling and laboratory experiments. The first goal of this research was to develop a spatially explicit lifecycle model, by integrating life cycle assessment (LCA), and Geographic Information Systems (GIS) analysis, for the evaluation of the environmental and economic …


Investigation Of Volatile Organic Compounds (Vocs) Detected At Vapor Intrusion Sites, Mohammadyousef Roghani Jan 2018

Investigation Of Volatile Organic Compounds (Vocs) Detected At Vapor Intrusion Sites, Mohammadyousef Roghani

Theses and Dissertations--Civil Engineering

This dissertation investigates unexplained vapor intrusion field data sets that have been observed at hazardous waste sites, including: 1) non-linear soil gas concentration trends between the VOC source (i.e. contaminated groundwater plume) and the ground surface; and, 2) alternative pathways that serve as entry points for vapors to infiltrate into buildings and serve to increase VOC exposure risks as compared to the classic vapor intrusion model, which primarily considered foundation cracks as the route for vapor entry. The overall hypothesis of this research is that theoretical knowledge of fate and transport processes can be systematically applied to vapor intrusion field …


Stormwater Capture In The Built Watershed: Fostering Public Awareness Of Water Conservation Through A Parcel-Level Approach To Stormwater Management, Benjamin Rigby Jan 2018

Stormwater Capture In The Built Watershed: Fostering Public Awareness Of Water Conservation Through A Parcel-Level Approach To Stormwater Management, Benjamin Rigby

Pitzer Senior Theses

As California contends with climate change and more extreme cycles of drought and deluge, water management agencies and conservation groups are looking towards solutions to the decreasing reliability of imported water supplies. Stormwater has historically been perceived as a threat to development but when captured properly, it presents a resource that can augment local water supplies. Solutions to water supply issues in California have traditionally employed technical and centrally controlled methods for importing water, but there is a growing understanding that parcel-level capture through vegetated swales presents an opportunity for reducing the impact that development has on California’s hydrology. Vegetated …


Dust Control Examination Using Computational Fluid Dynamics Modeling And Laboratory Testing Of Vortecone And Impingement Screen Filters, Ashish R. Kumar Jan 2018

Dust Control Examination Using Computational Fluid Dynamics Modeling And Laboratory Testing Of Vortecone And Impingement Screen Filters, Ashish R. Kumar

Theses and Dissertations--Mining Engineering

Heavy industries, such as mining, generate dust in quantities that present an occupational health hazard. Prolonged exposure to the respirable dust has been found to result in many irreversible occupational ailments in thousands of miners. In underground mining applications, a variety of scrubbing systems are used to remove dust near the zones of generation. However, the wire-mesh type fibrous screens in the flooded-bed dust scrubbers used on continuous miners, are prone to clogging due to the accumulation of dust particles. This clogging results in a reduced capture efficiency and a higher exposure to the personnel. This research establishes the Vortecone, …


Modeling Water Availability, Risk And Resilience In A Semi-Arid Basin In Southern Africa, Esther N. Mosase Jan 2018

Modeling Water Availability, Risk And Resilience In A Semi-Arid Basin In Southern Africa, Esther N. Mosase

Electronic Theses and Dissertations

Climate variability need to be incorporated into the management and planning of water resources, particularly in arid and semi-arid regions, where water availability is more sensitive to rainfall and air temperature. This study used modified Man-Kendall trend analysis test and ArcGIS to process data. Annual means of rainfall, minimum temperature and maximum temperature in the Limpopo River Basin (LRB) varied between 160 and 1109 mm, 8 °C to 20 °C and 23 °C to 32 °C respectively. The spatial pattern is generally increasing from west to east for rainfall and minimum temperature while maximum temperature increases from south to north …


Comparison Of Historical Precipitation For Aberdeen, Ipswich, And Eureka, South Dakota, Uday Singh Kshatriya Jan 2018

Comparison Of Historical Precipitation For Aberdeen, Ipswich, And Eureka, South Dakota, Uday Singh Kshatriya

Electronic Theses and Dissertations

The availability of water resources varies from time to time with the climate conditions. Keeping track of climate conditions would eventually benefit for the future predictions. The objective of this research was to compare and contrast the climate especially for Aberdeen, Ipswich and Eureka, South Dakota utilizing the historical monthly precipitation records and to develop the techniques that are reliable to estimate the missing data. For these necessary statistical analyses were performed using the monthly precipitation data from High Plains Regional Climate Center (HPRCC) for the annual and 8-Year periods for Aberdeen, Ipswich and Eureka, South Dakota. 63 water years …


A Development Of Travel Time Equation For Overland Flow As Affected By Vegetation, Naga Vara Prasad Ganti Jan 2018

A Development Of Travel Time Equation For Overland Flow As Affected By Vegetation, Naga Vara Prasad Ganti

Electronic Theses and Dissertations

In overland flow water research, travel time is a significant parameter used in estimating peak discharge in channels or rivers. Overland flow is assumed to be in turbulent condition to estimate travel time using Manning’s Velocity Equation (MVE). When the flow is in a laminar condition, Grismer’s Laminar Mean Velocity Equation (GLMVE) is applied but fails to consider the roughness parameter. A review of the literature shows numerous equations for overland travel time, but there is no known equation that determines the mean velocity of overland flow under laminar condition with a roughness coefficient or other coefficient related to the …


Evaluating The Effectiveness Of Biochar For Treating Wsu Parking Lot Runoff, Alan-Christian Thomas Jan 2018

Evaluating The Effectiveness Of Biochar For Treating Wsu Parking Lot Runoff, Alan-Christian Thomas

Research Opportunities for Engineering Undergraduates (ROEU) Program 2017-18

Various pollutants including pesticides, herbicides, automotive fluids, and excess nutrients from fertilizers are found in high concentrations in urban runoff. There are many technologies that can be used to control and redirect the water flow such as retention basins, constructed wetlands, and rain gardens; however, these methods are specifically focused on controlling water and not necessarily the nutrients and contaminants in the water. There has recently been an increased interest in the potential for using additional materials (e.g., compost, charcoal) to enhance the pollution treatment ability by either adding them to the soil or by engineering prefilters to remove pollutants …


2018 Nebraska Groundwater Quality Monitoring Report Jan 2018

2018 Nebraska Groundwater Quality Monitoring Report

Nebraska Department of Environmental Quality: Reports

The 2001 Nebraska Legislature passed LB329 (Neb. Rev. Stat. §46-1304) which, in part, directed the Nebraska Department of Environmental Quality (NDEQ) to report on groundwater quality monitoring in Nebraska. Reports have been issued annually since December 2001. The text of the statute applicable to this report follows: “The Department of Environmental Quality shall prepare a report outlining the extent of ground water quality monitoring conducted by natural resources districts during the preceding calendar year. The department shall analyze the data collected for the purpose of determining whether or not ground water quality is degrading or improving and shall present the …


Assessing The Feasibility Of Soil Infiltration Trenches For Highway Runoff Control On The Island Of Oahu, Hawaii, Martina Sobotkova, Jaromir Dusek, Ghasem Alavi, Laxman Sharma, Chittaranjan Ray Jan 2018

Assessing The Feasibility Of Soil Infiltration Trenches For Highway Runoff Control On The Island Of Oahu, Hawaii, Martina Sobotkova, Jaromir Dusek, Ghasem Alavi, Laxman Sharma, Chittaranjan Ray

Nebraska Water Center: Faculty Publications

The coastal waters of Hawaii are extremely important for recreation as well as for the health of the marine environment. Non-point source pollution from storm runoff poses a great threat to surface water quality in Hawaii. The State of Hawaii Department of Transportation (HDOT) includes infiltration trenches as a best management practice (BMP) option to reduce pollution caused by stormwater runoff. HDOT guidelines state that the implementation of BMPs is needed to reduce sediment and pollutant loads to streams and the ocean. In this study, the suitability of soils adjacent to highways on Oahu for the siting of infiltration trenches …


Exploring The Effects Of Zinc Nanoparticle Concentration, Antioxidant, And Media On Cilantro (Coriandrum Sativum), And Radish (Raphanus Sativus) Plants Growth, Venkata Laxma Reddy Pullagurala Jan 2018

Exploring The Effects Of Zinc Nanoparticle Concentration, Antioxidant, And Media On Cilantro (Coriandrum Sativum), And Radish (Raphanus Sativus) Plants Growth, Venkata Laxma Reddy Pullagurala

Open Access Theses & Dissertations

Engineered nanomaterials (ENMs) have proven to be one of the emerging chemicals of concern in the contemporary times. Soil acts as one of the major sinks of these ENMs. Reports have shown that ENMs have varied effects on soil biota. Particularly, their effects on plants are inconsistent. Amongst these ENMs, ZnO nanoparticles (nZnO) are the fourth largest raw materials in the nanotechnology industry. Globally, it is estimated that around 34,000 tons of n ZnO are utilized per year. The nZnO exposure on terrestrial plants yielded both beneficial as well as detrimental effects. Recently, there is an emerging evidence about the …


Pressure-Driven Stabilization Of Capacitive Deionization, Landon S. Caudill Jan 2018

Pressure-Driven Stabilization Of Capacitive Deionization, Landon S. Caudill

Theses and Dissertations--Mechanical and Aerospace Engineering

The effects of system pressure on the performance stability of flow-through capacitive deionization (CDI) cells was investigated. Initial data showed that the highly porous carbon electrodes possessed air/oxygen in the micropores, and the increased system pressure boosts the gases solubility in saline solution and carries them out of the cell in the effluent. Upon applying a potential difference to the electrodes, capacitive-based ion adsorption occurs in competition with faradaic reactions that consume oxygen. Through the addition of backpressure, the rate of degradation decreases, allowing the cell to maintain its salt adsorption capacity (SAC) longer. The removal of oxygen from the …


Evaluation, Improvement, And Application Of Models Of Environmental Fate And Transport Of Atmosphere-Surface Exchangeable Pollutants (Aseps), Tanvir Khan Jan 2018

Evaluation, Improvement, And Application Of Models Of Environmental Fate And Transport Of Atmosphere-Surface Exchangeable Pollutants (Aseps), Tanvir Khan

Dissertations, Master's Theses and Master's Reports

Certain toxic, semivolatile chemicals, also known as atmosphere-surface exchangeable pollutants (ASEPs) are emitted into the environment from anthropogenic activities and natural sources. This dissertation focused on the (i) evaluation and improvement of dry particle deposition and atmosphere-surface exchange parameterizations of ASEPs for use in chemical transport models (CTMs), and (ii) application of a dynamic multimedia model to examine recovery of Lake Superior from historical inputs of polychlorinated biphenyl (PCB) compounds (a class of ASEPs) contamination.

Current knowledge has been inadequate to propose quantitative measures of the relative performance of available dry particle deposition parameterizations. In Chapter 1 of this dissertation, …


Effects Of Land Development And Season On Heavy Metal Concentrations In Urban Streams, Helen Daigle Jan 2018

Effects Of Land Development And Season On Heavy Metal Concentrations In Urban Streams, Helen Daigle

REU Final Reports

Although it is generally understood that urban development can impact the quality of urban streams, there are many factors that affect the concentrations of pollutants being transferred from the built environment to a given output. This study examines the impact of land use surrounding urban streams, specifically, the degree of development and presence or absence of green infrastructure (GI) in these areas on heavy metal (HM) concentrations in Portland, Oregon. After collecting 1021 water quality samples from 2010-2018, we examined the difference in concentrations of HM pollutants across different combinations of land use and season. Increased levels of calcium, magnesium, …


A Model To Predict Concentrations And Uncertainty For Mercury Species In Lakes, Ashley Hendricks Jan 2018

A Model To Predict Concentrations And Uncertainty For Mercury Species In Lakes, Ashley Hendricks

Dissertations, Master's Theses and Master's Reports

To increase understanding of mercury cycling, a seasonal mass balance model was developed to predict mercury concentrations in lakes and fish. Results indicate that seasonality in mercury cycling is significant and is important for a northern latitude lake. Models, when validated, have the potential to be used as an alternative to measurements; models are relatively inexpensive and are not as time intensive. Previously published mercury models have neglected to perform a thorough validation. Model validation allows for regulators to be able to make more informed, confident decisions when using models in water quality management. It is critical to quantify uncertainty; …


Three-Dimensional Modeling Of Nitrate-N Transport In Vadose Zone: Roles Of Soil Heterogeneity And Groundwater Flux, Simin Akbariyeh, Shannon L. Bartelt-Hunt, Daniel D. Snow, Xu Li, Zhenghong Tang, Yusong Li Jan 2018

Three-Dimensional Modeling Of Nitrate-N Transport In Vadose Zone: Roles Of Soil Heterogeneity And Groundwater Flux, Simin Akbariyeh, Shannon L. Bartelt-Hunt, Daniel D. Snow, Xu Li, Zhenghong Tang, Yusong Li

Department of Civil and Environmental Engineering: Faculty Publications

Contamination of groundwater from nitrogen fertilizers in agricultural lands is an important environmental and water quality management issue. It is well recognized that in agriculturally intensive areas, fertilizers and pesticides may leach through the vadose zone and eventually reach groundwater. While numerical models are commonly used to simulate fate and transport of agricultural contaminants, few models have considered a controlled field work to investigate the influence of soil heterogeneity and groundwater flow on nitrate-N distribution in both root zone and deep vadose zone.

In this work, a numerical model was developed to simulate nitrate-N transport and transformation beneath a center …


Evaluating E. Coli Particle Attachment And The Impact On Transport During High Flows, Louis Amegbletor Jan 2018

Evaluating E. Coli Particle Attachment And The Impact On Transport During High Flows, Louis Amegbletor

Electronic Theses and Dissertations

Fecal indicator bacteria, including E. coli, are the leading cause of water quality impairments within assessed waters in the United States. The source of E. coli includes WWTP, leaking sewers, animal manure, wildlife, livestock, and stream bed sediment. Storm events contribute to bacteria loading within waters through wash-in of land sources of bacteria and resuspension of bacteria within sediments. Bacteria introduced into the water column are either attached to particles or are unattached (or free-living). The goal of this study was to examine the attachment of E. coli to different particle sizes, including their impact on contributing to water …


2017 Fall Engr333 Project Final Report (Section A), Trevor Nyeholt, Francis Kapesa, Justin Thalmayer, Erik Karlson, Kyle Van Veen, Kirk Brink, Steven Tarske, Brent Homan, Nathan De Haan, Paul Bootsma, Megan Anders, Philip Holmes, Melanie Fox, Noah Pirrotta, Abigail Berkompas, Ben Wellman, Halley Press, Christopher Greaves, Josh Templeman, Tim Bosch, Jake Zandstra, Hendrik Vermeulen Dec 2017

2017 Fall Engr333 Project Final Report (Section A), Trevor Nyeholt, Francis Kapesa, Justin Thalmayer, Erik Karlson, Kyle Van Veen, Kirk Brink, Steven Tarske, Brent Homan, Nathan De Haan, Paul Bootsma, Megan Anders, Philip Holmes, Melanie Fox, Noah Pirrotta, Abigail Berkompas, Ben Wellman, Halley Press, Christopher Greaves, Josh Templeman, Tim Bosch, Jake Zandstra, Hendrik Vermeulen

ENGR 333

Calvin College currently spends $836,000 annually on natural gas consumption. The engineering 333-A class was tasked with the question, "What would it take for Calvin College to save $75,000 per year on natural gas costs". The class was split into five groups (Boilers, Dorms and Dining Hall, Academic Buildings, Finance, and PE Complex) to research possible areas of savings. Through the class' research, it was determined that Calvin College has the potential savings of $87,000 a year through the reduction of natural gas usage.


2017 Fall Engr333 Project Final Report (Section B), Eric Ball, Mitchell Debruin, Raymond Kolocek, Edwin Kpodzro, Jacob Vandekieft, Nate Anderson, Brennan Steenhoek, Darbi Meyer, Derek Vermerris, Jessica Bouma, Devon Loerop, Reuben Saarloos, Richmond Amoh, Matthew Boelens, Tyson Butler, Laura Van Winkle, Alex Keizer, Kwame Ohemeng, Cameron Richman, Julie Van De Riet Dec 2017

2017 Fall Engr333 Project Final Report (Section B), Eric Ball, Mitchell Debruin, Raymond Kolocek, Edwin Kpodzro, Jacob Vandekieft, Nate Anderson, Brennan Steenhoek, Darbi Meyer, Derek Vermerris, Jessica Bouma, Devon Loerop, Reuben Saarloos, Richmond Amoh, Matthew Boelens, Tyson Butler, Laura Van Winkle, Alex Keizer, Kwame Ohemeng, Cameron Richman, Julie Van De Riet

ENGR 333

Currently, Calvin College spends $2.8M on electricity and natural gas. In the recent past Calvin has alleviated some of these costs by running a cogeneration system that combusts fuel and produces electricity and heat, this old system has since been removed due to age. With the old system removed Calvin is fully reliant on grid, leading to increased electricity cost. In addition to saving Calvin money, President Leroy formally signed the President’s Carbon Commitment that announced Calvin’s intent to be Carbon neutral by 2057. To meet both the cost and emissions saving needs, the objective of the energy savings project …


2017 Fall Engr333 Seminar Preservation, Trevor Nyeholt, Erik Karlson, Cam Richman, Tyson Butler Dec 2017

2017 Fall Engr333 Seminar Preservation, Trevor Nyeholt, Erik Karlson, Cam Richman, Tyson Butler

ENGR 333

File for student presentation, given by students in the Fall 2017 class of ENGR333.


2017 Fall Engr333 Poster (Section B), Eric Ball, Mitchell Debruin, Raymond Kolocek, Edwin Kpodzro, Jacob Vandekieft, Nate Anderson, Brennan Steenhoek, Darbi Meyer, Derek Vermerris, Jessica Bouma, Devon Loerop, Reuben Saarloos, Richard Amoh, Matthew Boelens, Tyson Butler, Laura Van Winkle, Alex Keizer, Kwame Ohemeng, Cameron Richman, Julie Van De Riet Dec 2017

2017 Fall Engr333 Poster (Section B), Eric Ball, Mitchell Debruin, Raymond Kolocek, Edwin Kpodzro, Jacob Vandekieft, Nate Anderson, Brennan Steenhoek, Darbi Meyer, Derek Vermerris, Jessica Bouma, Devon Loerop, Reuben Saarloos, Richard Amoh, Matthew Boelens, Tyson Butler, Laura Van Winkle, Alex Keizer, Kwame Ohemeng, Cameron Richman, Julie Van De Riet

ENGR 333

Previously, Calvin College had a cogeneration system with the purpose of generating electricity and heat, through the combustion of natural gas, for Calvin’s campus. The original co-gen system was removed in 2017 due to high costs associated with maintenance and operations. Without a co-gen system, Calvin College is fully dependent on the grid. To save money and help in the President’s Carbon Commitment, PCC, the mechanical engineering students of ENGR 333 (section B) propose the implementation of a new co-gen system.


2017 Fall Engr333 Poster (Section A), Trevor Nyeholt, Francis Kapesa, Justin Thalmayer, Erik Karlson, Kyle Van Veen, Kirk Brink, Steven Tarske, Brent Homan, Nathan De Haan, Paul Bootsma, Megan Anders, Philip Holmes, Melanie Fox, Noah Pirrotta, Abigail Berkompas, Ben Wellman, Halley Press, Christopher Greaves, Josh Templeman, Tim Bosch, Jake Zandstra, Hendrik Vermeulen Dec 2017

2017 Fall Engr333 Poster (Section A), Trevor Nyeholt, Francis Kapesa, Justin Thalmayer, Erik Karlson, Kyle Van Veen, Kirk Brink, Steven Tarske, Brent Homan, Nathan De Haan, Paul Bootsma, Megan Anders, Philip Holmes, Melanie Fox, Noah Pirrotta, Abigail Berkompas, Ben Wellman, Halley Press, Christopher Greaves, Josh Templeman, Tim Bosch, Jake Zandstra, Hendrik Vermeulen

ENGR 333

Calvin College uses 161,000 MMBTU of natural gas per year, which correlates to $836,000 of annual expenses. However Calvin could save as much as $240,000 on natural gas if they were as efficient as the top performer in an energy audit of similar colleges and universities in the Midwest, conducted by Sightlines Institute. The goal of this project was to see what actions could be taken to save the college $75,000 in annual natural gas costs.


College Of Engineering Senior Design Competition Fall 2017, University Of Nevada, Las Vegas Dec 2017

College Of Engineering Senior Design Competition Fall 2017, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge. The senior design competition helps focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects on …


Evaluation Of Water Resources And Hydraulic Influences In The Restoration Of The Western Part Of The Mesopotamian Marshlands, Ali Kareem Al-Quraishi Dec 2017

Evaluation Of Water Resources And Hydraulic Influences In The Restoration Of The Western Part Of The Mesopotamian Marshlands, Ali Kareem Al-Quraishi

Graduate Theses and Dissertations

The purpose of this study is to assess the water resources and water conveyance system of the western part of the Mesopotamian marshes (Al-Hammar marsh) as well as develop a water conveyance system to distribute water throughout the western Al-Hammar marsh. These processes are significant to identify the current restoration problems and help to create restoration strategies for the marsh. Also, proper management strategy to the Al-Hammar marsh is necessary to preserve the marsh ecosystem, irrigate lands, and provide domestic necessities in the villages.

The overall project is divided into three main chapters which address the current ecological and hydrological …


Three-Dimensional Vapor Intrusion Modeling Approach That Combines Wind And Stack Effects On Indoor, Atmospheric, And Subsurface Domains, Elham Shirazi, Kelly G. Pennell Dec 2017

Three-Dimensional Vapor Intrusion Modeling Approach That Combines Wind And Stack Effects On Indoor, Atmospheric, And Subsurface Domains, Elham Shirazi, Kelly G. Pennell

Civil Engineering Faculty Publications

Vapor intrusion (IV) exposure risks are difficult to characterize due to the role of atmospheric, building and subsurface processes. This study presents a three-dimensional VI model that extends the common subsurface fate and transport equations to incorporate wind and stack effects on indoor air pressure, building air exchange rate (AER) and indoor contaminant concentration to improve VI exposure risk estimates. The model incorporates three modeling programs: (1) COMSOL Multiphysics to model subsurface fate and transport processes, (2) CFD0 to model atmospheric air flow around the building, and (3) CONTAM to model indoor air quality. The combined VI model predicts AER …


Geophysical Delineation Of Megaporosity And Fluid Migration Pathways For Geohazard Characterization Within The Delaware Basin, Culberson County, Texas, Jonathan David Woodard Dec 2017

Geophysical Delineation Of Megaporosity And Fluid Migration Pathways For Geohazard Characterization Within The Delaware Basin, Culberson County, Texas, Jonathan David Woodard

Electronic Theses and Dissertations

ABSTRACT

Differential dissolution of gypsum karst within the Delaware Basin poses a significant threat to infrastructure that society depends on. The study area is located in Culberson County, Texas and traverses a distance of approximately 54 kilometers along RM 652 within the Gypsum Plain which is situated on the northern margin of the Chihuahua Desert and includes outcrops of Castile and Rustler strata that host karst geohazards. Regions of karst geohazard potential have been physically surveyed proximal to the study area in evaporites throughout the Castile Formation outcrop; minimal hazards, in comparison to the Castile Formation, have been documented in …


Longitudinal Thermal And Solute Dynamics In Regulated Rivers, Muhammad Rezaul Haider Dec 2017

Longitudinal Thermal And Solute Dynamics In Regulated Rivers, Muhammad Rezaul Haider

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Dam releases increase river stage and can reverse groundwater movement into and out of the river. As the flood, thermal, and solute waves travel downstream in a regulated river, the size of the waves is anticipated to be affected both by river processes and exchanges with near river groundwater. This study established a modeling framework to quantify the influences of the groundwater exchanges on the temperatures and solute concentration dynamics along regulated rivers. The wave properties, volume of exchanges, conservative solute mass exchanges, and heat energy exchanges were calculated as a function of time and distance downstream. Results show that …


Investigation Of Setting Time And Compressive Strength Of Ready-Mixed Concrete Blended With Returned Fresh Concrete, Negasi Niguse Gebremichael Dec 2017

Investigation Of Setting Time And Compressive Strength Of Ready-Mixed Concrete Blended With Returned Fresh Concrete, Negasi Niguse Gebremichael

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Center for Sustainable Transportation Infrastructure (CSTI), in its 2012 study, estimated that out of all the concrete leaving the plant, between 2% and 7% of concrete returns to the plant unused as a returned fresh concrete (RFC). Disposal of both the truck wash water and RFC is a growing concern for the industry. Most industry personnel contacted during the investigation, agree that reusing is superior to recycling of this substantial RFC economically and environmentally. This study will determine if the reuse of RFC in subsequent batches compromises the quality of newly blended concrete.

The effect of RFC on fresh …