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Articles 31 - 60 of 231
Full-Text Articles in Engineering
Investigating The Use Of Passive Acoustics As A Surrogate Method Of Monitoring Coarse Bedload Transport In Rivers And Streams Via Laboratory Experiments And Field Studies, Bradley Goodwiller
Investigating The Use Of Passive Acoustics As A Surrogate Method Of Monitoring Coarse Bedload Transport In Rivers And Streams Via Laboratory Experiments And Field Studies, Bradley Goodwiller
Electronic Theses and Dissertations
The movement of coarse gravel in rivers in streams is important for many applications including wildlife habitation, river morphology, infrastructure maintenance and marine navigation. Physical sampling remains the most accurate method of determining coarse bedload transport but it can be expensive, dangerous and flow intrusive. Surrogate methods of monitoring bedload transport is an active area of research worldwide. One such method is the use of passive acoustics to record the sound generated when gravel particles in motion impact each other or the particles on the bed. This dissertation presents research and development that has been conducted on three key areas …
Raptor Codes For Biawgn Channel: Snr Mismatch And The Optimality Of The Inner And Outer Rates, Hussein Fadhel
Raptor Codes For Biawgn Channel: Snr Mismatch And The Optimality Of The Inner And Outer Rates, Hussein Fadhel
Electronic Theses and Dissertations
Fountain codes are a class of rateless codes with two interesting properties, first, they can generate potentially limitless numbers of encoded symbols given a finite set of source symbols, and second, the source symbols can be recovered from any subset of encoded symbols with cardinality greater than the number of source symbols. Raptor codes are the first implementation of fountain codes with linear complexity and vanishing error floors on noisy channels. Raptor codes are designed by the serial concatenation of an inner Luby trans-form (LT) code, the first practical realization of fountain codes, and an outer low-density parity-check (LDPC) code. …
Mac-Phy Frameworks For Lte And Wifi Networks' Coexistence Over The Unlicensed Band, Hadi Ahmad Kasasbeh
Mac-Phy Frameworks For Lte And Wifi Networks' Coexistence Over The Unlicensed Band, Hadi Ahmad Kasasbeh
Electronic Theses and Dissertations
The main focus of this dissertation is to address these issues and to analyze the interactions between LTE and WiFi coexisting on the unlicensed spectrum. This can be done by providing some improvements in the first two communication layers in both technologies. Regarding the physical (PHY) layer, efficient spectrum sensing and data fusion techniques that consider correlated spectrum sensing readings at the LTE/WiFi users (sensors) are needed. Failure to consider such correlation has been a major shortcoming of the literature. This resulted in poorly performing spectrum sensing systems if such correlation is not considered in correlated-measurements environments.
Historical Groundwater Data Analysis Of The Wilcox Aquifers In Lafayette County, Mississippi, Adam Schildhammer
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 …
Design And Analysis Of Efficient Parallel Bayesian Model Comparison Algorithms, Robert Wesley Henderson
Design And Analysis Of Efficient Parallel Bayesian Model Comparison Algorithms, Robert Wesley Henderson
Electronic Theses and Dissertations
Bayesian model comparison provides a rational and consistent method for applying logic and probability to the problem of evaluating models. Model comparison requires numerical techniques that are usually very time consuming to run. This dissertation proposes extensions to several existing numerical model comparison techniques, including nested sampling and thermodynamic integration, that incorporate parallel algorithm design to achieve significant speed-ups. Serial computer performance gains have sloin recent years, and most processing speed improvements are seen in the area of parallel architectures. This work discusses the design, theoretical analysis, and empirical analysis of these algorithms, focusing on the performance of these algorithms …
Investigative Study Of Poly(Ionic) Liquid Incorporation In Resin Wafer Electrodeionization For Improved Specific Energy Consumption, Angela Fasuyi
Investigative Study Of Poly(Ionic) Liquid Incorporation In Resin Wafer Electrodeionization For Improved Specific Energy Consumption, Angela Fasuyi
Electronic Theses and Dissertations
An electrokinetic separation method known as Resin Wafer Electrodeionization (RW-EDI) is recognized as a promising technology for energy efficient desalination of brackish water. However RW-EDI is limited by an inherent drawback of its ion exchange media that prevents the largescale deployment of this technology. This research was undertaken to optimize the conventional resin wafer used in RW-EDI through the incorporation of high conducting polyionic liquids (PILs). It was hypothesized that by the changing non-conducting polyethylene binder with a PIL binder in conventional resin wafer configurations ion conductivity within the resin bed would be enhanced and could lead to an improvement …
Automation Of Data Collection From An Anechoic Chamber, Thomas S. Garner
Automation Of Data Collection From An Anechoic Chamber, Thomas S. Garner
Electronic Theses and Dissertations
This paper describes the calibration methods and the process that is used on the Ole Miss electrical engineering anechoic chamber. Furthermore the MATLAB code that operates the anechoic chamber has been updated to collect sweep data. The GUI also now includes a tab for calibration giving the user the ability to calibrate for their desired frequency range for when there is not sufficient calibration data already available.
A Study Of Cooperative Spectrum Sharing Schemes For Internet Of Things Systems, Adham Hagag
A Study Of Cooperative Spectrum Sharing Schemes For Internet Of Things Systems, Adham Hagag
Electronic Theses and Dissertations
The Internet of Things (IoT) has gained much attention in recent years with the massive increase in the number of connected devices. Cognitive Machine-to-Machine (CM2M) communications is a hot research topic in which a cognitive dimension allows M2M networks to overcome the challenges of spectrum scarcity, interference, and green requirements. In this paper, we propose a Generalized Cooperative Spectrum Sharing (GCSS) scheme for M2M communication. Cooperation extends the coverage of wireless networks as well as increasing their throughput while reducing the energy consumption of the connected low power devices. We study the outage performance of the proposed GCSS scheme for …
Computational Modeling And Simulations Of Condition Deterioration To Enhance Asphalt Highway Pavement Design And Asset Management, Zul Fahmi Bin Mohamed Jaafar
Computational Modeling And Simulations Of Condition Deterioration To Enhance Asphalt Highway Pavement Design And Asset Management, Zul Fahmi Bin Mohamed Jaafar
Electronic Theses and Dissertations
A nation’s economy and prosperity depend on an efficient and safe transportation network for public mobility and freight transportation. A country’s road network is recognized as one of the largest public infrastructure assets. About 93 percent of 2.6 million miles of paved roads and highways in the United States (U.S.) are surfaced with asphalt. Longitudinal roughness, pavement cracking, potholes, and rutting are the major reasons for rehabilitation of asphalt roads. Billions of dollars are required annually for the maintenance and rehabilitation of road networks. If timely maintenance and rehabilitation are not performed, the pavement damages inflicted by heavy traffic repetitions …
Evaluating The Effects Of Water Influx On The Mississippi Sound: Current Vs. Historical Relationships, Jarett Lee Bell
Evaluating The Effects Of Water Influx On The Mississippi Sound: Current Vs. Historical Relationships, Jarett Lee Bell
Electronic Theses and Dissertations
This research investigated the influence of the opening of the Bonnet Carre Spillway and other fresh water inputs on the Mississippi Sound. The Bonnet Carre Spillway was completed in 1931 and was constructed to protect New Orleans whenever the Mississippi River is at flood stage. The spillway drains into Lake Pontchartrain a brackish-water lagoon north of New Orleans which then drains into Lake Borgne and subsequently into the Mississippi Sound. The inflow of water from the spillway changes the water chemistry of all receiving water bodies and impacts the waters of the Mississippi Gulf Coast. We collected in-situ temperature specific …
Use Of Seismic Refraction In Determining Rock Mass Anisotropy, Mohammad Najmush Sakib Oyan
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 …
Analytical Modeling And Life Cycle Assessment Of A Solar Powered Vapor Absorption Cooling System, Harold A. Walters
Analytical Modeling And Life Cycle Assessment Of A Solar Powered Vapor Absorption Cooling System, Harold A. Walters
Electronic Theses and Dissertations
Vapor absorption cooling systems (VACS) offer an environmentally friendly alternative to the standard vapor compression cooling systems (VCCS) for cooling homes, businesses, factories, and other buildings. VACS use low-grade thermal energy to achieve a cooling effect and require minimal electrical input for the liquid solution pump used for circulation within the system. The thermal energy which powers these systems can be provided through several means; one popular form is through the use of solar thermal collectors. This paper provides a process for determining the overall size and configuration of the VACS depending upon the operating conditions of selected components. A …
Decentralized Detection With Correlated Gaussian Observations: Parallel And Tandem Networks With Two Sensors, Shailee Yagnik
Decentralized Detection With Correlated Gaussian Observations: Parallel And Tandem Networks With Two Sensors, Shailee Yagnik
Electronic Theses and Dissertations
Signal detection in cognitive radio involves the determination of presence or absence of a primary user signal so that the secondary user may opportunistically gain access when the spectrum is unoccupied. In decentralized sensing scheme, two or more secondary users sense the spectrum, process individual observation and then pass the quantized data to a fusion center where a decision with regard to which hypothesis being true, that is, a signal being present or absent, is made. In the second part of the thesis, we study Bayes error performance of two-sensor tandem network designed to detect the presence or absence of …
Cellulose Nanocrystals As 'Green' Emulsifiers Stabilized Crude Oil In Water Emulsions, Omayma Alazzam
Cellulose Nanocrystals As 'Green' Emulsifiers Stabilized Crude Oil In Water Emulsions, Omayma Alazzam
Electronic Theses and Dissertations
This study examines the ability of CNC to stabilize crude o/w Pickering emulsions. The effects of concentration of CNC, ionic strength of the aqueous phase, volume fraction of crude oil to water, and the presence of divalent ions on the stability of crude o/w emulsions were examined. Emulsions stabilized with different concentrations of CNC vary from 0.1 to 1.0wt% were prepared and examined by visual assessment for creaming analysis and microscopic pictures to analyze droplet size and size distribution. Low concentration of CNC as 0.1wt% didn’t help with forming stable emulsions. As the concentration of CNC stabilized the emulsions increased, …
Utilizing Of Magnesium Oxysulfate Binders For Additive Construction Applications, Hatem Hashem Al-Masaeid
Utilizing Of Magnesium Oxysulfate Binders For Additive Construction Applications, Hatem Hashem Al-Masaeid
Electronic Theses and Dissertations
This dissertation is serving multiple transdisciplinary top-notch material design and technological topics. It is a proof of concept of the feasibility of 3D printing using Magnesium Oxysulfate (MOS) binder as an alternative to the ordinary Portland cement (OPC) to be utilized in terrestrial and extraterrestrial additive construction (AC) fields. MOS paste and mortar are characterized physically, chemically, and mechanically. The characterization results conducted in this research show how MOS’s properties can be controlled to match the 3D printing requirements by manipulating the MOS’s ingredients proportions.
Field Testing And Simulation Of Vadose-Zone Recharge Wells In The Mississippi River Valley Alluvial Aquifer As An Artificial Recharge Method, Kyungwon Kwak
Electronic Theses and Dissertations
Increasing concerns regarding depletion of groundwater in the Delta region of Mississippi have led to a need to augment natural recharge. Infiltration basins are often one of the simplest means of artificially recharging aquifers. However the Delta has a layer of clay and silt at the surface so it is a better idea to use vadose-zone recharge wells that are not limited by the surficial layer of fine soils. The purpose of this study is to use full-scale field testing to assess the feasibility of using vadose-zone wells for artificial recharge of the Mississippi River Valley alluvial aquifer by using …
Optimizing The Performance Of Complex Engineering Systems Aided By Artificial Neural Networks, Khalil Qatu
Optimizing The Performance Of Complex Engineering Systems Aided By Artificial Neural Networks, Khalil Qatu
Electronic Theses and Dissertations
In the first problem Polyetherimide graphene nanoplatelets papers (PEIGNP) were tested with different graphene loadings varying from 0-97 weight percent (WT%). The resulting stress-strain curves were utilized to develop two ANN models. Stress-controlled and strain-controlled models. Both models shoan excellent correlation to the experimental. Several Mechanical properties were calculated from the predicted stress-strain curves namely; toughness maximum strength maximum strain and maximum tangent modulus. Both models captured the same overall behavior of the PEIGNP composite. However the strain-controlled model was found to predict lower stress than the stress-controlled model. Finally a Graphical User Interface (GUI) was developed to aid in …
Ionic Liquid-Based Composite Thin-Films For Selective Ion Separations In Electrodialysis, Saloumeh Kolahchyan
Ionic Liquid-Based Composite Thin-Films For Selective Ion Separations In Electrodialysis, Saloumeh Kolahchyan
Electronic Theses and Dissertations
The onset of climate change and rising global population has caused greater water scarcity, a considerable problem which threatens our world. The demand for fresh water is pushing a fast development of water purification technologies. Among these technologies, membrane-based water desalination processes are playing an interesting role in both academia and industry. Electrodialysis (ED) is an electro-membrane separation process aimed at water treatment through ion removal, which is achieved through the selective control and transport of ionic species. ED is a popular water treatment method; however, it is limited by membrane scaling, lack of ion selectivity, and high energy consumption …
A Numerical Study Of Granular Dam-Break Flows, Nuttita Pophet
A Numerical Study Of Granular Dam-Break Flows, Nuttita Pophet
Electronic Theses and Dissertations
Granular flows are mass movements of mixtures of solid particles and interstitial fluid. Examples include landslides, debris flows and tailings dam-break flows. These types of flows are often catastrophic events, and cover a wide range of phenomena of interest to both scientists and engineers. The mechanical properties of granular materials and the hydraulic behavior of the flows originate from solid and fluid phases, their distribution and interaction. Understanding the behavior of these types of flows and developing reliable predictive models are important.
An Improved 3d Complex-Envelope Four-Stage Adi-Fdtd Using The Fundamental Scheme, Qi Liu
An Improved 3d Complex-Envelope Four-Stage Adi-Fdtd Using The Fundamental Scheme, Qi Liu
Electronic Theses and Dissertations
Three corresponding reference methods are developed. The CE explicit FDTD method is used to solve the problem with a point source and perfect electric conductor (PEC) boundaries. The problem with a point source and absorbing boundary conditions (ABC) is solved by the 3D free-space Green's function in the frequency domain, and then transformed to the time domain using the inverse fast Fourier transform (IFFT). For the problem with a plane wave and ABC, the frequency-domain solution is obtained using the volume integral equations and method of moments (VIE-MOM), and is then transformed into the time-domain solution using the IFFT. Comparison …
Groundwater Transfer And Injection Pilot Project: Construction Of A Three Dimensional Groundwater Flow Model, Wesley Bluvstein
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 Framework For Assessing Water Quality, Prioritizing Recovery Potential, And Analyzing Placement Of Best Management Practices, Tadesse Animaw Sinshaw
A Framework For Assessing Water Quality, Prioritizing Recovery Potential, And Analyzing Placement Of Best Management Practices, Tadesse Animaw Sinshaw
Electronic Theses and Dissertations
Motivated by the U.S. EPA goals, this research developed a framework to support identification and restoration of nutrient-impaired water bodies. The study objectives were developing total nitrogen (TN) and total phosphorus (TP) prediction models, evaluating the impact of social indicators on assessing recovery potential, and developing a spatial decision support system for choice and placement of best management practices (BMPS). An artificial neural network was used to develop TN and TP predictive regional models for U.S. lakes using easily measurable and cost-effective variables. The performance of models was superior for regions trained with larger datasets and/or regions with lower temperature …
Energy Harvesting Nanocoated Piezoceramics For Low Power Systems, Quinten Humphrey
Energy Harvesting Nanocoated Piezoceramics For Low Power Systems, Quinten Humphrey
Electronic Theses and Dissertations
No abstract provided.
Elastodynamic Model For Wind Induced Ground Motion, Mohammad Mohammadi
Elastodynamic Model For Wind Induced Ground Motion, Mohammad Mohammadi
Electronic Theses and Dissertations
No abstract provided.
On The Design Of Physical Layer Rateless Codes, Amrit Kharel
On The Design Of Physical Layer Rateless Codes, Amrit Kharel
Electronic Theses and Dissertations
Codes that are capable of generating any number of encoded symbols from a given number of source symbols are called rateless codes. Luby transform (LT) codes are the first practical realization of rateless codes while Raptor codes are constructed by serially concatenating LT codes with high-rate outer low-density parity-check (LDPC) codes. Although these codes were originally developed for binary erasure channel (BEC), due to their rateless feature, they are being investigated and designed for their use in noisy channels. It is known that LT codes are the irregular non-systematic rateless counterpart of low-density generator-matrix (LDGM) codes. Therefore, the first part …
Multiobjective Reservoir Optimization Using Genetic Algorithm, Seyma Tiryakioglu
Multiobjective Reservoir Optimization Using Genetic Algorithm, Seyma Tiryakioglu
Electronic Theses and Dissertations
This thesis investigates the optimization of energy generation in a multipurpose reservoir. The objective functions and the constraints for the multiobjective optimization of reservoir operation for maximization of energy production involve the solution of a set of nonlinear equations governing pressure flow in penstock and turbine system and the hydropower generation. The hydropower generation also requires operational rules that define how the reservoir storage volume must be used at different storage levels. For these reasons, the present thesis uses genetic algorithm (GA) functions available in Matlab to perform the multiobjective optimization of hydropower energy production. Multiobjective optimization is based on …
Variables Governing The Initial Stages Of The Synergisms Of Ultrasonic Treatment Of Biochar In Water Saturated With Carbon Dioxide, Adedapo Reuben Adeniyi
Variables Governing The Initial Stages Of The Synergisms Of Ultrasonic Treatment Of Biochar In Water Saturated With Carbon Dioxide, Adedapo Reuben Adeniyi
Electronic Theses and Dissertations
This work investigates the initial stage of the synergistic processes of acoustic treatment of biochar in water saturated with CO2 (AIChE Journal, 2014;60:1054-1065). Treatments with switchgrass and miscanthus biochars have been conducted to examine the effects of acoustic intensity, biochar/H2O ratio, CO2 concentrations of the solution, and that in the headspace above the solution. The changes in biochars’ heating values, carbon and hydrogen contents, internal surface area, and pore size distribution have significant technological implications and are the focal points of this study. The miscanthus and switchgrass biochars were produced via pyrolysis process at 700 oC and 550 oC, respectively. …
Molecular Dynamics Simulation Of Polymer Nanocomposites In Extreme Environments, Farzin Rahmani
Molecular Dynamics Simulation Of Polymer Nanocomposites In Extreme Environments, Farzin Rahmani
Electronic Theses and Dissertations
In this dissertation, lower length scale phenomena associated with the responses of hybrid materials to harsh and extreme environments were studied. The goal of this research was to reveal the underlying mechanisms of damage mitigation in these materials and the role that interface, and relevant material component interactions play in the overall material response. First, the thermal decomposition behavior of a technologically important material system, i.e., pristine graphene (PG) and graphene oxide (GO) reinforced poly(ethylene oxide) (PEO), was investigated using a reactive molecular dynamics simulation methodology. The simulations were performed in both non-isothermal (dynamic gravimetric) and isothermal modes of decomposition. …
Integrity Assessment Of Earthen Dams And Levees Using Cross-Plot Analysis Of Seismic Refraction And Electrical Resistivity Tomograms, Leti Teklu Wodajo
Integrity Assessment Of Earthen Dams And Levees Using Cross-Plot Analysis Of Seismic Refraction And Electrical Resistivity Tomograms, Leti Teklu Wodajo
Electronic Theses and Dissertations
Geophysical methods provide a rapid, economical, non-invasive, and spatial coverage of the subsurface in terms of geophysical properties. On the other hand, geophysical methods can generate multiple geophysical anomalies. An anomaly on a seismic refraction or an electrical resistivity tomogram is an area that has different values compared to its surrounding. Geophysical anomalies in dams and levees can be due to the overall heterogeneity of the subsurface, structures such as principal spillways, artifacts of inversion software, or to a true compromised location, such as an air void due to internal erosion or seepage. Therefore, there is uncertainty involved with using …
A Comparative Case Study Of Reflection Seismic Imaging Method, Moones Alamooti
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. …