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2014

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Articles 931 - 960 of 1522

Full-Text Articles in Civil and Environmental Engineering

Improving The Physical Processes And Model Integration Functionality Of An Energy Balance Model For Snow And Glacier Melt, Avirup Sen Gupta May 2014

Improving The Physical Processes And Model Integration Functionality Of An Energy Balance Model For Snow And Glacier Melt, Avirup Sen Gupta

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Hindu-Kush Himalayan region possesses a large resource of snow and ice, which acts as a freshwater reservoir for irrigation, domestic water consumption or hydroelectric power for billions of people in South Asia. Monitoring hydrologic resources in this region is challenging because of the difficulty of installing and maintaining a climate and hydrologic monitoring network, limited transportation and communication infrastructure and difficult access to glaciers. As a result of the high, rugged topographic relief, ground observations in the region are extremely sparse. Reanalysis data offer the potential to compensate for the data scarcity, which is a barrier in hydrological modeling …


Laboratory Modeling Of Erosion Potential Of Earthen Embankments In Contact With Open Bedrock Joints, Joseph T. Zaleski May 2014

Laboratory Modeling Of Erosion Potential Of Earthen Embankments In Contact With Open Bedrock Joints, Joseph T. Zaleski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Earthen dams are often built into bedrock abutments and on bedrock foundations. Bedrock joints naturally occur in bedrock materials. These bedrock joints create voids for ground water to pass through. Historically earthen dams were sometimes built in direct contact with the bedrock joints, causing a contact point between the soil of the dam and the flowing water. It has been engineering practice to place grout into exposed bedrock joints for some time now. However, soil is not always cleaned out of bedrock joints before they are grouted, which leaves a weakness for water to push through.

The purpose of this …


Use Of Semi-Analytical Solutions To Examine Parameter Sensitivity And The Role Of Spatially Variable Stream Hydraulics In Transient Storage Modeling, Noah M. Schmadel May 2014

Use Of Semi-Analytical Solutions To Examine Parameter Sensitivity And The Role Of Spatially Variable Stream Hydraulics In Transient Storage Modeling, Noah M. Schmadel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Anticipating how stream water quality will respond to change, such as increased pollution or water diversions, requires knowledge of the main mechanisms controlling water and chemical constituent movement and a reasonable representation of those mechanisms. By deriving mathematical models to represent a stream system and collecting supporting field-based measurements, water quality response can be predicted. However, because each stream is unique and the movement of water and constituents is spatially and temporally complex, assessing whether the stream is appropriately represented and whether predictions are trustworthy is still a challenge within the scientific and management communities.

Building on decades of stream …


An Ecohydrological Perspective On Drought-Induced Forest Mortality, Anthony J. Parolari, Gabriel Katul, Amilcare Porporato May 2014

An Ecohydrological Perspective On Drought-Induced Forest Mortality, Anthony J. Parolari, Gabriel Katul, Amilcare Porporato

Civil and Environmental Engineering Faculty Research and Publications

Regional‐scale drought‐induced forest mortality events are projected to become more frequent under future climates due to changes in rainfall patterns. The occurrence of these mortality events is driven by exogenous factors such as frequency and severity of drought and endogenous factors such as tree water and carbon use strategies. To explore the link between these exogenous and endogenous factors underlying forest mortality, a stochastic ecohydrological framework that accounts for random arrival and length of droughts as well as responses of tree water and carbon balance to soil water deficit is proposed. The main dynamics of this system are characterized with …


Estimating Unsaturated Flow Properties In Coarse Conglomeratic Sediment, Michael James Thoma Jr. May 2014

Estimating Unsaturated Flow Properties In Coarse Conglomeratic Sediment, Michael James Thoma Jr.

Boise State University Theses and Dissertations

In this dissertation, I address the lack of knowledge of unsaturated flow in coarse, conglomeratic sediment by determining if functional θ-ψ-K relationships, specifically van Genuchten-Mualem (VGM) relationships, developed to predict unsaturated flow in relatively fine-grained sediment can be directly applied to coarse, conglomeratic sediment. In the summer of 2011, a field-scale infiltration test was conducted at the Boise Hydrogeophysical Research Site to determine if functional ψ-θ-K relationships could be applied to infiltration in coarse, conglomeratic sediment, and to estimate parameter values for the VGM relationships. Vertically and laterally distributed ψ(t) and θ( …


Bs News May/June May 2014

Bs News May/June

Building Services Engineering

No abstract provided.


Modeling Historic Columbia River Flood Impacts, Lumas Helaire, Andrew Mahedy, Stefan A. Talke, David A. Jay May 2014

Modeling Historic Columbia River Flood Impacts, Lumas Helaire, Andrew Mahedy, Stefan A. Talke, David A. Jay

Civil and Environmental Engineering Faculty Publications and Presentations

The Lower Columbia River Estuary (LCRE) has undergone extensive modifications since the 19th century. Construction of dams, installation of jetties and dikes, dredging of the navigation channel and filling in of tidal wetlands have all contributed significantly to alterations in tidal dynamics and the flow regime, with consequences for habitat inundation and salinity intrusion. In this talk we discuss the development and implementation of a 19th century flow model for the LCRE, using a digital elevation model based on historic bathymetry. The model has been calibrated with recently rediscovered and digitized tide data from the 19th century. …


Developing A South Carolina Traffic Incident Management Plan Along The I-26 Corridor Between Columbia And Charleston, Laura Rowe May 2014

Developing A South Carolina Traffic Incident Management Plan Along The I-26 Corridor Between Columbia And Charleston, Laura Rowe

All Theses

Traffic Incident Management (TIM) programs are used in many states across the nation to efficiently clear interstate incidents and alleviate congestion in response to incidents. The overarching goal of this research is to maintain safety of the motoring public and incident responders while reducing congestion, secondary collisions, and traffic delays from incidents that occur on South Carolina highways. To reduce incident clearance times along the I-26 corridor between Columbia and Charleston through the implementation of a Traffic Incident Management (TIM) Program, several objectives for this thesis were established to move toward the goal, including; defining gaps between national TIM best-practices …


Interpolation And Validation Of Arced Labyrinth Weir Discharge Coefficients, Rhen Daniel Thurgood May 2014

Interpolation And Validation Of Arced Labyrinth Weir Discharge Coefficients, Rhen Daniel Thurgood

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Arced labyrinth weirs have been researched in recent years as a viable option to help increase spillway discharge capacity. Previously published data have indicated the hydraulic efficiency of these weirs with several configurations at different sidewall angles (α=6°, α=12°, and α=20°), expressed in terms of the discharge coefficients. These published discharge coefficient data were used in the current study, along with new experimental data, to develop a better understanding of the accuracy associated with interpolating arced labyrinth weir discharge coefficients. Discharge coefficient data for a 16° arced labyrinth weir (of similar physical size to the arced labyrinth weirs in the …


Increasing Storm Tides In New York Harbor, 1844–2013, Stefan A. Talke, Philip M. Orton, David A. Jay May 2014

Increasing Storm Tides In New York Harbor, 1844–2013, Stefan A. Talke, Philip M. Orton, David A. Jay

Civil and Environmental Engineering Faculty Publications and Presentations

Three of the nine highest recorded water levels in the New York Harbor region have occurred since 2010 (March 2010, August 2011, and October 2012), and eight of the largest twenty have occurred since 1990. To investigate whether this cluster of high waters is a random occurrence or indicative of intensified storm tides, we recover archival tide gauge data back to 1844 and evaluate the trajectory of the annual maximum storm tide. Approximately half of long-term variance is anticorrelated with decadal-scale variations in the North Atlantic Oscillation, while long-term trends explain the remainder. The 10 year storm tide has increased …


Phosphorus Mobility In The Shallow Unconfined Aquifer At Pineview Reservoir, Utah, Christine Rumsey May 2014

Phosphorus Mobility In The Shallow Unconfined Aquifer At Pineview Reservoir, Utah, Christine Rumsey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Significant phosphorus transport is occurring in the groundwater surrounding Pineview Reservoir. A set of investigations was completed to identify factors contributing to phosphorus mobility. Water quality monitoring was conducted to understand groundwater characteristics and phosphorus movement. Several water quality parameters were evaluated to specifically determine whether septic systems influence groundwater quality. Results indicate that septic systems pollute at least two locations in the aquifer around the reservoir. Given this information, it may be necessary to implement advanced septic system treatment options to reduce the amount of phosphorus in groundwater.

Experiments were conducted on two aquifer sediment types to identify factors …


Bridge Failure Rates, Consequences, And Predictive Trends, Wesley Cook May 2014

Bridge Failure Rates, Consequences, And Predictive Trends, Wesley Cook

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The intent of this investigation is to assess the number of bridge collapses in the United States, describe, in a numerical form, negative impacts resulting from collapsed bridges, and, last, analyze conditions of bridges prior to collapse and note similarities. Bridge collapse data is scarcely recorded, as such; an isolated region (New York State) over a period of time (25 years), wherein data has been collected of this nature, was used to determine the number of bridge collapses in the region annually. Probability and statistics were used to estimate the average number of bridge collapses throughout the United States and …


Water Use On The Las Vegas Strip: Assessment And Suggestions For Conservation, Suzanne H. Trabia May 2014

Water Use On The Las Vegas Strip: Assessment And Suggestions For Conservation, Suzanne H. Trabia

Honors College Theses

Due to stresses on the water supply in southern Nevada, which include an average of three million tourists per month and an ongoing drought since the year 2000, water conservation is imperative in order to sustain the growing urban area of Las Vegas. The purpose of this study is to assess water use in fourteen casinos on and off the Las Vegas Strip (the main boulevard of the largest casinos in Las Vegas) in order to suggest approaches for water conservation, such as reducing, reusing, and modifying the current system. Since data on water consumption is not publicly available, five …


Characterization Of Mc252 Subtidal And Intertidal Oil Mats On A Coastal Headland Beach, Allyson C. Lutz May 2014

Characterization Of Mc252 Subtidal And Intertidal Oil Mats On A Coastal Headland Beach, Allyson C. Lutz

Honors Capstones

No abstract provided.


Density Functional Theory Study Of The Thermodynamics Of Catalytic Remediation Of Nitrate In Water, Lizzie Bollmann May 2014

Density Functional Theory Study Of The Thermodynamics Of Catalytic Remediation Of Nitrate In Water, Lizzie Bollmann

All Theses

Over 1 billion people worldwide lack access to safe drinking water and 5,000 people die each day due to drinking contaminated water. With the development of new industries, new substances and chemicals are entering the waters every day, and the current water treatment processes are unable to remove them entirely. For example, agriculture is the world's heaviest consumer of water, and nitrates and nitrites from fertilizers are washed away with the water to rivers and streams. These chemicals can cause problems to humans and to the environment. To humans, they can cause methemoglobinemia, also known as 'blue baby syndrome'. To …


Adsorption Of Synthetic Organic Chemicals: A Comparison Of Superfine Powdered Activated Carbon With Powdered Activated Carbon, Semra Bakkaloglu May 2014

Adsorption Of Synthetic Organic Chemicals: A Comparison Of Superfine Powdered Activated Carbon With Powdered Activated Carbon, Semra Bakkaloglu

All Theses

In literature, manufacturer-supplied powdered activated carbon has been ground to produce submicron particles with mean diameter lower than 1µm for use as an adsorbent during water treatment. Superfine powdered activated carbon (SPAC) can be used for removal of natural organic matter as well as synthetic organic chemicals (SOCs) from water. It has been suggested that SPAC has higher adsorption capacity than powdered activated carbon (PAC) due to larger external surface area and mesopore volume. Another advantage of SPAC over PAC is the faster uptake rate for both NOM and SOC during adsorption owing to small particle size. Therefore, understanding SPAC …


Arsenic(V) Reduction In Relation To Iron(Iii) Transformation And Molecular Analysis Of Arsenate Reductase (Arra) Gene Within Sediments Of A Northern Utah, Basin-Fill Aquifer, Babur S. Mirza, Subathra Muruganandam, Xianyu Meng, Darwin L. Sorensen, Ryan Dupont, Joan E. Mclean May 2014

Arsenic(V) Reduction In Relation To Iron(Iii) Transformation And Molecular Analysis Of Arsenate Reductase (Arra) Gene Within Sediments Of A Northern Utah, Basin-Fill Aquifer, Babur S. Mirza, Subathra Muruganandam, Xianyu Meng, Darwin L. Sorensen, Ryan Dupont, Joan E. Mclean

Civil and Environmental Engineering Faculty Publications

Basin-fill aquifers of the Southwestern United States are associated with elevated concentrations of arsenic (As) in groundwater. Many private domestic wells in the Cache Valley Basin, UT, have As concentrations in excess of the U.S. EPA drinking water limit. Thirteen sediment cores were collected from the center of the valley at the depth of the shallow groundwater and were sectioned into layers based on redoxmorphic features. Three of the layers, two from redox transition zones and one from a depletion zone, were used to establish microcosms. Microcosms were treated with groundwater (GW) or groundwater plus glucose (GW+G) to investigate the …


Isolated And Ephemeral Wetlands Of Southern Appalachia: Biotic Communities And Environmental Drivers Across Multiple Temporal And Spatial Scales, Joanna Hawley May 2014

Isolated And Ephemeral Wetlands Of Southern Appalachia: Biotic Communities And Environmental Drivers Across Multiple Temporal And Spatial Scales, Joanna Hawley

All Dissertations

Throughout the world, wetlands are known to support a wide variety of taxa as well as high levels of biodiversity and species richness. Although the ecological significance of wetlands is well documented in the scientific literature, efforts to map and assess wetlands on regional or national scales (e.g., National Wetlands Inventory (NWI)) often overlook wetlands which are either very small (< 1 ha) or have ephemeral hydroperiods. While the vast majority of wetland research in the southeastern United States has focused on wetlands distributed across the coastal plain ecoregion, very little information exists on small and/or ephemeral wetlands in areas of southern Appalachia, although there are several notable exceptions. Despite the paucity of small wetland data in this region, the southeastern US is known as a hotspot for both aquatic biodiversity and species endemism. My goal with this project was to examine the biotic communities inhabiting small, ephemeral and geographically-isolated wetlands to identify the major environmental drivers that contribute to observed community patterns and species' distributions. I studied a set of small, mostly-ephemeral, mostly-isolated wetlands (N = 41) in the upper Piedmont and lower Blue Ridge ecoregions of South Carolina from January-June of 2010 and 2011 and focused my efforts on describing the structure, biotic communities and surrounding habitat characteristics of my study wetlands. I observed high levels of species richness and biodiversity in this previously-undocumented wetland system, despite the small size and ephemeral nature of study wetlands. My results indicated that the amphibian and benthic invertebrate communities of small, ephemeral wetlands responded to different environmental drivers (e.g., wetland depth, area, hydroperiod, canopy cover, surrounding land use types) occurring across multiple spatial and temporal scales. Additionally, the amphibian community was significantly influenced by a number of environmental variables occurring at both the within-pond scale and larger spatial scales (250 m, 500 m and 1 km surrounding land cover variables). By contrast, the benthic invertebrate community was significantly influenced primarily by variables occurring at the within-pond scale. This wetland system also served as both breeding and overwintering habitat for a variety of species such as wood frogs (Lithobates sylvatica), spotted salamanders (Ambystoma maculatum), bullfrogs (Lithobates catesbeiana), cricket frogs (Acris crepitans). This study highlights the ecological importance of small, ephemeral aquatic habitats in a region where little research exists regarding such systems; these often-unnoticed ecosystems are likely the result of a combination of historical anthropogenic and natural environmental process. These legacy wetlands (i.e., wetlands that are the unintended result of some human-induced environmental change in either the recent or long-term past) are found ubiquitously across the landscape and are often missed by coarse-filter mapping approaches (e.g., National Wetlands Inventory). I observed many study wetlands to be extremely small in size (< 0.05 ha) and that many wetlands were habitats of circumstance and opportunity rather than of permanence and predictability. The ephemerality of the majority of study wetlands demonstrates the biological significance of small, temporary habitats for many species requiring these habitats for breeding activity. Despite the small size and ephemeral nature of my study wetlands, I found that these wetlands represented a large proportion of amphibian biodiversity in the regional species pool and thus, are an important conservation feature at the local, landscape and regional scales. My study demonstrates that small, semi-isolated, mostly-ephemeral wetlands in southern Appalachia support high levels of biodiversity and are an important asset deserving of further study and conservation recognition.


The Development Of Empirical Models To Evaluate Energy Use And Energy Cost In Wastewater Collection, David Young May 2014

The Development Of Empirical Models To Evaluate Energy Use And Energy Cost In Wastewater Collection, David Young

All Dissertations

This research introduces a unique data analysis method and develops empirical models to evaluate energy use and energy cost in wastewater collection systems using operational variables. From these models, several Best Management Processes (BMPs) are identified that should benefit utilities and positively impact the operation of existing infrastructure as well as the design of new infrastructure. Further, the conclusions generated herein display high transferability to certain manufacturing processes. Therefore, it is anticipated that these findings will also benefit pumping applications outside of the water sector. Wastewater treatment is often the single largest expense at the local government level. Not surprisingly, …


Usu Concrete Canoe, Promontory, Nathaniel Laurence Decker May 2014

Usu Concrete Canoe, Promontory, Nathaniel Laurence Decker

Undergraduate Honors Capstone Projects

In 1863, while the Civil War was dividing the East, a monumental project began in the West. Plans had been finalized for a railroad that would unify the country in commerce and migration. Two companies accepted the challenge of laying track across over 1700 miles of North American soil, from Sacramento, California to Omaha, Nebraska. The Union Pacific Railroad would come from the East and the Central Pacific Railroad from the West. Governor Leland Stanford of California broke ground for the project on January 8, 1863, and the line was finished at Promontory Summit, UT on May 10, 1869 (NPS, …


Scalable, Solar Powered Membrane-Based Water Purification Systems For Community Development In Developing Countries, Yung Wong May 2014

Scalable, Solar Powered Membrane-Based Water Purification Systems For Community Development In Developing Countries, Yung Wong

Doctoral Dissertations and Master's Theses

This manuscript style thesis presents a community development model developed at Embry-Riddle Aeronautical University (ERAU) to deliver sustainable water purification systems and originate a companion micro-business to sell excess clean water in communities in Haiti. Since 2010, students and faculty from ERAU have partnered with strategic partners to not only provide clean water to their in-country operations but also provide an opportunity for economic growth through a clean water selling micro-business. Water, sanitation, and hygiene (WASH) training is also implemented to aid in community buy-in. Lessons learned from the history of foreign aid to developing countries is taken into account …


Dynamic Excitation Related Uncertainty In Ambient Vibration Testing Of A Truss Bridge, Ryan T. Dufour May 2014

Dynamic Excitation Related Uncertainty In Ambient Vibration Testing Of A Truss Bridge, Ryan T. Dufour

Civil Engineering Undergraduate Honors Theses

The aging and deteriorating state of bridges in the US, along with the many limitations of the visual inspection data that is used for assessing and evaluating their condition, have provided motivation for research on experimental methods to quantitatively describe and evaluate their in-situ performance and condition. Ambient vibration testing is one such global characterization approach that has been widely explored due to its low cost and ease of implementation for in-service bridges. The testing is used to identify the modal properties of the structure, typically the natural frequencies, mode shapes, and damping ratios. Although ambient vibration testing has been …


Evaluation Of The Effects Of Dynamic Excitation Characteristics On Ambient Vibration Test Results For A Multi-Girder Bridge, Gibran Santana May 2014

Evaluation Of The Effects Of Dynamic Excitation Characteristics On Ambient Vibration Test Results For A Multi-Girder Bridge, Gibran Santana

Civil Engineering Undergraduate Honors Theses

The bridge population in the US is currently aging and deteriorating rapidly. More than 30% of the bridges across the country have already exceeded their expected design life. Therefore, it is important to develop more timely, reliable and quantitative alternatives to the qualitative visual inspection approach that is currently used to evaluate these structures. One experimental approach that has been researched extensively for quantitatively characterize bridges is Ambient Vibration Testing (AVT) also known as Operational Modal Analysis (OMA). In this approach, the vibration responses of a structure due to unmeasured and uncontrolled ambient dynamic excitation are measured and analyzed to …


Temperature Sensitivity Of Foamed Warm Mix Asphalt, Ryan Michael Hagedorn May 2014

Temperature Sensitivity Of Foamed Warm Mix Asphalt, Ryan Michael Hagedorn

Civil Engineering Undergraduate Honors Theses

Foamed warm mix asphalt (WMA) is a technology that is beginning to be utilized across the United States. Often, producers are placing foamed WMA at decreased temperatures without fully understanding the properties of this relatively new product. By studying the volumetric properties of laboratory produced foamed WMA, this study sought to better understand the temperature sensitivity of foamed WMA and the potential factors that contribute to this sensitivity. Two mix designs containing primarily limestone aggregate were tested using differing binder grades. It was determined that binder grade, binder source and potentially the inclusion of recycled asphalt pavement all influence how …


Examination Of Nitrogen To Phosphorus Ratio In Nutrient Removal From Wastewater Through Chlorella Vulgaris, Courtney L. Hill May 2014

Examination Of Nitrogen To Phosphorus Ratio In Nutrient Removal From Wastewater Through Chlorella Vulgaris, Courtney L. Hill

Civil Engineering Undergraduate Honors Theses

A need for phosphorus removal is becoming increasingly evident as some wastewater treatment plants struggle to meet wastewater effluent nutrient requirements. High nutrient levels in wastewater effluents have also caused ongoing tension between the state of Oklahoma and Arkansas regarding the pollution of the Illinois River. This research seeks to establish the relationship between nitrogen to phosphorus ratio in wastewater and the level of nutrient reduction using Chlorella vulgaris. Seed cultures of Chlorella vulgaris were added into solutions with various ratios of nitrate to phosphate representative of treated domestic wastewater and the removal of nitrogen and phosphorus were measured in …


Shear Capacity Of Prestressed Lightweight Self-Consolidating Concrete, Micah Alan Wyssmann May 2014

Shear Capacity Of Prestressed Lightweight Self-Consolidating Concrete, Micah Alan Wyssmann

Civil Engineering Undergraduate Honors Theses

In prestressed members, self-consolidating concrete (SCC) has in some cases exhibited lower shear capacity than conventional concrete, which has been attributed to decreased aggregate interlock. However, little data is currently available to assess whether use of lightweight aggregate in prestressed SCC beams has further impact on aggregate interlock and shear strength. This study measured the shear capacity of six prestressed beams made from three different concrete mixtures: lightweight self-consolidating concrete (LWSCC) with expanded shale aggregate, LWSCC with expanded clay aggregate, and control normal weight SCC with limestone aggregate. Predicted shear capacities were determined based on current ACI Building Code and …


Development Of A Visualization System For Highway Safety Management Using Safety Analyst, Indira Khanal May 2014

Development Of A Visualization System For Highway Safety Management Using Safety Analyst, Indira Khanal

UNLV Theses, Dissertations, Professional Papers, and Capstones

The AASHTOWare software, Safety Analyst, is a state-of-the-art tool with significant capabilities and advanced analytical methods for comprehensive analysis and management of highway safety. However, currently, this tool provides very limited visualization capabilities. To address this limitation, this study proposes a Visualization System for Safety Analyst that provides graphical displays, including location and color-coded information for each module. In addition, the system generates charts, which have various degrees of resolution and aggregation; tables; and a report summarizing safety performance measures. The system can use Google Maps and/or ESRI ArcGIS to generate the graphical displays. The advantage of using Google Maps …


Algae: Opportunities For Biomass Feedstock Production, Wastewater Treatment And Educational Outreach, Trina Cassandra Halfhide May 2014

Algae: Opportunities For Biomass Feedstock Production, Wastewater Treatment And Educational Outreach, Trina Cassandra Halfhide

USF Tampa Graduate Theses and Dissertations

Algae are a diverse group of simple organisms that lack roots, stems or leaves and are able to use sunlight, carbon dioxide, and nutrients to produce complex compounds, such as carbohydrates, proteins and lipids. These compounds, especially lipids, are highly sought-after by agricultural, nutraceutical and energy interests. Although there is great potential for algae derived biofuels, there are technical and economic challenges associated with their cultivation. Relevant to this dissertation, the environmental impacts associated with algae cultivation can be reduced by using municipal and agricultural wastewaters as a water and nutrient source. This research was divided into three sections to …


Assessing The Impacts Of Unrestricted Pesticide Use In Small-Scale Agriculture On Water Quality And Associated Human Health And Ecological Implications In An Indigenous Village In Rural Panam[Aacute], Sarah Louise Watson May 2014

Assessing The Impacts Of Unrestricted Pesticide Use In Small-Scale Agriculture On Water Quality And Associated Human Health And Ecological Implications In An Indigenous Village In Rural Panam[Aacute], Sarah Louise Watson

USF Tampa Graduate Theses and Dissertations

In 2014, the global pesticide industry's projected worth is $52 billion and by 2020, the developing world will make up one-third of the world's chemical production and consumption. Pesticides can have unintended negative consequences for human health and the environment, especially in the developing world where regulations are loose or nonexistent. One country with unrestricted use of pesticides is Panam[aacute], especially in Santa Rosa de Cucunatí. In this indigenous village, small-scale farmers and ranchers spray paraquat, glyphosate, picloram, and 2,4-D at higher elevations than the spring water source of a gravity-fed water system, the river, and the village. The objective …


Finite Difference Modeling Of Surface-~Wave Scattering For Shallow Cavity Detection, Heston Travis Norcott May 2014

Finite Difference Modeling Of Surface-~Wave Scattering For Shallow Cavity Detection, Heston Travis Norcott

UNLV Theses, Dissertations, Professional Papers, and Capstones

Data collection and analysis of scattering of Rayleigh-type surface waves are investigated for locating shallowly buried cavities. Surface-based seismic experiments conducted by others at the University of Nevada, Las Vegas (UNLV) Engineering Geophysics Test Site (EGTS) demonstrate scattering of Rayleigh waves caused by buried empty barrels (essentially air-filled cavities). The interpretation of the data is complicated by factors such as the presence of a high-velocity geologic layer just below the cavity.

This research uses a finite-difference seismic wave propagation code to compute time histories for a model that represents the Engineering Geophysics Test Site. By adding cavities to a background …