Engineering Commons^™

Physical, Chemical, And Mineralogical Controls On Retardation Of Anatoxin-A Migration By Sorption To Natural Soils With Implications For Groundwater Protection, Justin L. Hobart, Andrew M. O’Reilly, Jennifer N. Gifford

Faculty and Student Publications

Increasing prevalence of cyanotoxins in surface water bodies worldwide threatens groundwater quality when contaminated water recharges an aquifer through natural or artificial means. The subsurface fate of anatoxin-a (ATX) is not well studied. Laboratory batch experiments were performed to expand the current knowledge of ATX sorption affinities to geologic media, with a focus on natural soil (Vertisol, Ultisol, Alfisol, and Inceptisol) and physical, chemical, and mineralogical characteristics. For a range of aqueous ATX concentrations (0.3–14 μg/L), linear, Freundlich, and Langmuir isotherms fit observed data well (r2 = 0.92–1.00, RMSE = 0.4–6.3 μg/kg). Distribution coefficient (Kd) and retardation factor (Rf) values …

Metasurface Cloaks To Decouple Closely Spaced Printed Dipole Antenna Arrays Fed By A Microstrip-To-Balanced Transmission-Line Transition, Doojin Lee, Alexander B. Yakovlev

Faculty and Student Publications

In this work, we present a numerical study of 1D and 2D closely spaced antenna arrays of microstrip dipole antennas covered by a metasurface in order to properly cloak and decouple the antenna arrays operating at neighboring frequencies. We show that the two strongly coupled arrays fed by a microstrip-to-balanced transmission-line transition are effectively decoupled in 1D and 2D array scenarios by covering the dipole antenna elements with an elliptically shaped metasurface. The metasurface comprises sub-wavelength periodic metallic strips printed on an elliptically shaped dielectric cover around the dipole antennas and integrated with the substrate. We present a practical design …

Wetting-Driven Formation Of Present-Day Loess Structure, Yanrong Li, Weiwei Zhang, Shengdi He, Adnan Aydin

Faculty and Student Publications

© 2020 The Authors Present-day loess, especially Malan loess formed in Later Quaternary, has a characteristic structure composed of vertically aligned strong units and weak segments. Hypotheses describing how this structure forms inside original loess deposits commonly relate it to wetting-drying process. We tested this causal relationship by conducting unique experiments on synthetic samples of initial loess deposits fabricated by free-fall of loess particles. These samples were subjected to a wetting-drying cycle, and their structural evolutions were documented by close-up photography and CT scanning. Analysis of these records revealed three key stages of structural evolution: initiation (evenly distributed cracks appear …

A Mathematical Framework For Estimating Risk Of Airborne Transmission Of Covid-19 With Application To Face Mask Use And Social Distancing, Rajat Mittal, Charles Meneveau, Wen Wu

Faculty and Student Publications

© 2020 Author(s). A mathematical model for estimating the risk of airborne transmission of a respiratory infection such as COVID-19 is presented. The model employs basic concepts from fluid dynamics and incorporates the known scope of factors involved in the airborne transmission of such diseases. Simplicity in the mathematical form of the model is by design so that it can serve not only as a common basis for scientific inquiry across disciplinary boundaries but it can also be understandable by a broad audience outside science and academia. The caveats and limitations of the model are discussed in detail. The model …

Load-Balancing Rendezvous Approach For Mobility-Enabled Adaptive Energy-Efficient Data Collection In Wsns, Jian Zhang, Jian Tang, Zhonghui Wang, Feng Wang, Gang Yu

Faculty and Student Publications

Copyright © 2020 KSII The tradeoff between energy conservation and traffic balancing is a dilemma problem in Wireless Sensor Networks (WSNs). By analyzing the intrinsic relationship between cluster properties and long distance transmission energy consumption, we characterize three node sets of the cluster as a theoretical foundation to enhance high performance of WSNs, and propose optimal solutions by introducing rendezvous and Mobile Elements (MEs) to optimize energy consumption for prolonging the lifetime of WSNs. First, we exploit an approximate method based on the transmission distance from the different node to an ME to select suboptimal Rendezvous Point (RP) on the …

Revisiting Lightweight Encryption For Iot Applications: Error Performance And Throughput In Wireless Fading Channels With And Without Coding, Yazid M. Khattabi, Mustafa M. Matalgah, Mohammed M. Olama

Faculty and Student Publications

© 2013 IEEE. Employing heavy conventional encryption algorithms in communications suffers from added overhead and processing time delay; and in wireless communications, in particular, suffers from severe performance deterioration (avalanche effect) due to fading. Consequently, a tremendous reduction in data throughput and increase in complexity and time delay may occur especially when information traverse resource-limited devices as in Internet-of-Things (IoT) applications. To overcome these drawbacks, efficient lightweight encryption algorithms have been recently proposed in literature. One of those, that is of particular interest, requires using conventional encryption only for the first block of data in a given frame being transmitted. …

Cooperative Relay Selection For Load Balancing With Mobility In Hierarchical Wsns: A Multi-Armed Bandit Approach, Jian Zhang, Jian Tang, Feng Wang

Faculty and Student Publications

© 2013 IEEE. Energy efficiency is the major concern in hierarchical wireless sensor networks(WSNs), where the major energy consumption originates from radios for communication. Due to notable energy expenditure of long-range transmission for cluster members and data aggregation for Cluster Head (CH), saving and balancing energy consumption is a tricky challenge in WSNs. In this paper, we design a CH selection mechanism with a mobile sink (MS) while proposing relay selection algorithms with multi-user multi-armed bandit (UM-MAB) to solve the problem of energy efficiency. According to the definition of node density and residual energy, we propose a conception referred to …

Timcc: On Data Freshness In Privacy-Preserving Incentive Mechanism Design For Continuous Crowdsensing Using Reverse Auction, Xiaoqiang Ma, Weiwei Deng, Feng Wang, Menglan Hu, Fei Chen, Mohammad Mehedi Hassan

Faculty and Student Publications

© 2013 IEEE. As an emerging paradigm that leverages the wisdom and efforts of the crowd, mobile crowdsensing has shown its great potential to collect distributed data. The crowd may incur such costs and risks as energy consumption, memory consumption, and privacy leakage when performing various tasks, so they may not be willing to participate in crowdsensing tasks unless they are well-paid. Hence, a proper privacy-preserving incentive mechanism is of great significance to motivate users to join, which has attracted a lot of research efforts. Most of the existing works regard tasks as one-shot tasks, which may not work very …

Urea Functionalization Of Ultrasound-Treated Biochar: A Feasible Strategy For Enhancing Heavy Metal Adsorption Capacity, Baharak Sajjadi, James William Broome, Wei Yin Chen, Daniell L. Mattern, Nosa O. Egiebor, Nathan Hammer, Cameron L. Smith

Faculty and Student Publications

© 2018 Elsevier B.V. The main objective of a series of our researches is to develop a novel acoustic-based method for activation of biochar. This study investigates the capability of biochar in adsorbing Ni(II) as a hazardous contaminant and aims at enhancing its adsorption capacity by the addition of extra nitrogen and most probably phosphorous and oxygen containing sites using an ultrasono-chemical modification mechanism. To reach this objective, biochar physically modified by low-frequency ultrasound waves (USB) was chemically treated by phosphoric acid (H3PO4) and then functionalized by urea (CO(NH2)2). Cavitation induced by ultrasound waves exfoliates and breaks apart the regular …

Analysis Of Crush Resistance And Mississippi-Sourced Sands To Determine Potential As Proppant Sands, Ryann C. Lam

Honors Theses

Proppant is a media used in hydraulic fracturing to bear in-situ stresses in order to maintain fracture networks, which act as highly permeable pathways for hydrocarbon recovery. Proppant can be made from a variety of materials such as glass, ceramic beads, sand particles, and more. Proppants are characterized by their size, sorting, roundness, and sphericity. These properties help determine the compressive strength of the pack proppant. This study focuses on these properties for natural sand. The purpose of this study is to evaluate the viability of lower-quality sands as proppant sands by testing the affect these properties have on the …

Evaluating The Use Of Suas-Derived Imagery For Monitoring Flood Protection Infrastructure, Eleanor Mei Dietz

Electronic Theses and Dissertations

In the US there are approximately 33,000 miles of levees. This includes 14,500 miles of levee systems associated with US Army Corps of Engineers programs and approximately 15,000 miles from other state and federal agencies. More than 14 million people live behind levees and associated flood prevention infrastructure. Monitoring and risk assessment are an on-going process, especially during times of flood conditions. The city of New Orleans was heavily impacted by Hurricane Katrina in 2005 by storm surges and intense rainfall. The impact of the hurricane was substantial enough to cause levee failure and I-wall toppling where many of the …

Use Of Seismic Refraction In Determining Rock Mass Anisotropy, Mohammad Najmush Sakib Oyan

Electronic Theses and Dissertations

Seismic refraction is a popular method used by geological/geotechnical engineers to understand subsurface conditions. This method along with information collected from borings produce a realistic image of the ground beneath us. The goal of this study is to define and test a set of procedures to use seismic refraction alone to create high quality images of subsurface conditions. The focus is on areas with several meters of soil overlain by bedrock. The application of these procedures will minimize construction costs by eliminating the need for multiple boreholes. The results show that two important criteria must be met for successful application …

Historical Groundwater Data Analysis Of The Wilcox Aquifers In Lafayette County, Mississippi, Adam Schildhammer

Electronic Theses and Dissertations

Lafayette County, Mississippi, is located in the northern central part of the state and relies on groundwater resources for all of the municipal water needs in the county. The population is increasing in the county; therefore, groundwater withdrawals are as well. With such a high demand on groundwater, it is important to have an understanding of the historical trends of the groundwater levels to determine is the population is over pumping the available supply. The Meridian-upper Wilcox aquifer and the lower Wilcox aquifer are the two groundwater sources for the county. In order to fully understand the behaviors of these …

Developing A Calibrated Seepage Meter To Measure Stream-Aquifer Interaction In The Mississippi Delta, Wesley J. Bolton

Electronic Theses and Dissertations

The Mississippi Alluvial Plain (MAP) is a premier region for irrigated agriculture in the United States producing approximately 9 billion dollars in annual revenues. The region receives around 138 cm of precipitation annually; however irrigation is necessary to maximize crop yields as most of the precipitation does not occur during the growing season. There are 8 million irrigated acres within the Mississippi Alluvial Plain. The source of most of the irrigated water is the surficial aquifer in the Mississippi Embayment the Mississippi River Valley Alluvial Aquifer (MRVAA) and due to the reliance on irrigation for maximum crop yields recent potentiometric …

Groundwater Transfer And Injection Pilot Project: Construction Of A Three Dimensional Groundwater Flow Model, Wesley Bluvstein

Electronic Theses and Dissertations

The Mississippi River Valley Alluvial Aquifer has experienced substantial groundwater declines in eastern Arkansas and northwest Mississippi due largely to irrigation for rice corn soybeans and other water intensive crops. To alleviate groundwater decline and ensure future sustainability of water resources the U.S. Department of Agriculture has in conjunction with the U.S. Geological Survey and the University of Mississippi initiated studies to determine potential avenues of remediation. Options include improved irrigation efficiency installation of surface weirs inter-basin transfers and groundwater transfer and injection. This study develops a three-dimensional groundwater flow model of a withdrawal well adjacent to a river for …

A Comparative Case Study Of Reflection Seismic Imaging Method, Moones Alamooti

Electronic Theses and Dissertations

Reflection seismology is the most comand effective method to gather information on the earth interior. The quality of seismic images is highly variable depending on the complexity of the underground and on how seismic data are acquired and processed. One of the crucial steps in this process, especially in layered sequences with complicated structure, is the time and/or depth migration of seismic data. The primary purpose of the migration is to increase the spatial resolution of seismic images by repositioning the recorded seismic signal back to its original point of reflection in time/space, which enhances information about the complex structure. …

Comparing The Depositional Environment Of The Upper Smackover Formation In Southwestern Clarke County, Mississippi And Brooklyn/ Little Cedar Creek Field, Alabama, Elsie Ekene Okoye

Electronic Theses and Dissertations

This research evaluated the depositional settings of the upper Smackover formation in southwestern Clarke County (scc), Mississippi and compared its facies to those of the Brooklyn and little cedar creek fields (bf/lcc) in Conecuh and Escambia Counties, Alabama. The Smackover formation has been a prolific oil producing formation in the Gulf of Mexico since its discovery in Union County, Arkansas in 1937. The discovery of the lcc in 1994 and the bf in 2007 has generated additional interest in the Smackover. The bf/ lcc occur near the updip limit of the upper Jurassic (Oxfordian) Smackover formation. These fields produce from …

Reconstructing Lithofacies Of The Norphlet Formation (Jurassic) As Potential Exploration Targets: Little Cedar Creek And Brooklyn Fields, Southwest Alabama, Catherine E. Henry

Electronic Theses and Dissertations

The Norphlet Formation is a Jurassic-aged siliciclastic unit located across the southeastern United States and offshore Gulf of Mexico. The eolian dune sands present in the Norphlet Formation serve as oil and gas reservoirs, making the formation of particular interest to oil and gas companies. Stable Appalachian ridges are the source of the Norphlet Formation, however deposition is related to complex faults and structures resulting from movement of the Louann Salt. Erosion of the ancestral Appalachian Mountains resulted in the deposition of four main lithofacies: basal shales, conglomerates and conglomeratic sandstones, the Denkman Sandstone member, and a redbed succession. Additionally, …

Acoustic Behavior Of Soil Reinforced With Grass Roots, Blake Armstrong

Electronic Theses and Dissertations

Civil engineering practice has shown that vegetative roots on slopes and streambanks can substantially increase shear strength of soil and reduce erosion. Research has been done to understand and quantify the effect. Most studies have been conducted on slopes and streambanks with woody vegetation. Past research has used a perpendicular root model to predict increase in cohesion, or shear strength, due to the mobilization of roots' tensile strength. Acoustics can be used to monitor internal changes of soil by interacting with soil particles and interstitial fluids. Compressional wave, or p-wave, velocity can be used to predict changes in effective stress …

Empirical Modeling Of Piping Along Mississippi River Levees In Southwestern Illinois, Rebecca F. Shields

Electronic Theses and Dissertations

No abstract provided.

Modeling Roughness Of Rock Discontinuity Surfaces, Christopher Pickering

Electronic Theses and Dissertations

The aim of this thesis is to propose a new methodology of quantifying the rock discontinuity condition of roughness through the physically based modeling approach of signal analysis. The development of this method came about after investigation into the use of qualitative categorizations of roughness from the RMR rating system within rock engineering system matrices. In an attempt to assign significant values to these generalized qualitative descriptions, the standard joint roughness coefficient (JRC) profiles were initially examined through basic measurements, such as aperture and ramp angle. Following these initial measurements and identification of inconsistencies in the wave parameters of the …

Subsurface Discontinuity Analysis & Modeling For The Federal Waste Disposal Facility And Compact Waste Disposal Facility Landfills, Shuang Cao

Electronic Theses and Dissertations

This research considers discontinuities mapped by Waste Control Specialists LLC to support the site conditions and performance analysis of the Compact Waste Disposal Facility and the Federal Waste Disposal Facility excavations constructed near Andrews, Texas. Discontinuities observed in excavation walls contain a limited number of discontinuities shoevidence of previous fluid movement. While no networks of such discontinuities were observed in the field, the potential for such networks may exist. This research is significant in understanding the performance of these waste facilities by modeling multiple realizations of possible fracture configurations in three-dimensional spatial models of the type of discontinuities observed in …

Influence Of Capillary Heterogeneity On Leakage Of Co2 From A Borehole, Frank Roecker

Electronic Theses and Dissertations

We used a modified invasion percolation (MIP) model to examine the effect of capillary heterogeneity, buoyancy forces, and viscous forces on the surface area and saturation of a CO2 plume leaking into a shallow aquifer. The purpose of this study is to provide a better understanding of how CO 2 migrates from a borehole, which is essential in implementing effective simulation and monitoring regimes to accurately detect CO2 leakage from sequestration sites. The MIP model approach will simulate invasion of a light non-wetting fluid (e.g., CO2) into a medium initially saturated with a dense wetting fluid (water). The style of …

A Field Validation Of Dam Indexing Methods In Mississippi, Steven Thomas Fox

Electronic Theses and Dissertations

Indexing methods are applied to dam inventories throughout the United States to assist in prioritizing resources to maintain aging dam structures. Three published indexing methods and one proposed method were applied to 24 dams through Mississippi. The majority of dams in Mississippi have little to no information concerning the performance records or design specifics of a given dam. Field assessments were conducted to determine the physical condition of each dam, identify potentially deficiencies at dams, and calculate a consequence in the event of a dam failure. The results of the four indexing methods will be compared and advantages and disadvantages …

Characterization Of The Engineering Properties And Economic Potential Of The Transitional Clay Unit Of The Ripley Formation, Northeast Mississippi, Richard Christopher Wheeler

Electronic Theses and Dissertations

Expansive soils, throughout Mississippi and the U.S., have long been a source of problems within the engineering and construction industries, leading to billions of dollars in damage annually. Along with being a source of problems, the clays throughout Mississippi are also of economic importance, being mined for a variety of uses. In this study, the engineering properties of the transitional clay facies of the Ripley Formation are studied, to characterize the swell potential of the transitional clay, and to assist with the evaluation of the possible commercial uses of the soil. The transitional clay is an Upper Cretaceous unit characterized …

Petrology Of North Mississippi Bauxite : A Case For Depositional Bauxite And Kaolin, Charles Nelson Thompson

Electronic Theses and Dissertations

In the past 55 years, there has been considerable debate over the stratigraphic position, genesis, and economic value of North Mississippi bauxite. The aluminum rich deposits are unlike most deposits found around the world. The deposits are associated with 200-300 foot thick marine to nonmarine clays overlain by feldspar poor, fluvial-deltaic sediments. The possible source areas are composed of limestone, marls, sand, and muds ranging in age from Late Cretaceous to Late Paleocene. These factors prohibit the direct application of previous theories derived from studies outside Mississippi. The deposits, therefore, cannot be considered a textbook example of bauxite formation.

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