Engineering Commons^™

Exploring Spatial Associations And Complex Interactions Between Geotechnical Properties And Electrical Resistivity Values In Clayey Soils, Mina Zamanian

Civil Engineering Dissertations - Archive

ABSTRACT: A successful design and construction of infrastructure systems such as highways and bridges highly depend on accurate estimation of geotechnical properties and understanding their spatial distributions, especially in reliability-based designs such as the load and resistance factor design (LRFD) method. Insufficient and inaccurate subsurface information has a major contribution to cost overruns and delays in up to 50% of all infrastructure projects. Insufficient site investigation may also contribute to inadequate or conservative designs, leading to costly failures or increased project costs. Hence, geophysical methods, such as electrical resistivity imaging, that can potentially transform the existing subsurface investigations are used …

The Impact Of Improper Solid Waste Management On Public Health Of African Cities. The Case Of Addis Ababa City, Ethiopia., Tesfaye Abebe Alemu

Civil Engineering Dissertations - Archive

Many African cities are generating an ever-increasing amount of waste and the effectiveness of their solid waste collection and disposal systems is currently declining. Therefore, research has been striving to develop a sustainable and integrated solid waste management system that fits the current challenges facing the local environment. The objective of this study is to analyze the impact of improper solid waste management that affects the air and water quality of the near Koshe open dump site and around the Addis Ababa City, and their adverse effect on the public health living around them. The rapid increase of population in …

The Road Map For Sustainable Waste Management In The Federal Democratic Republic Of Ethiopia, Assegid Yimenu

Civil Engineering Dissertations - Archive

Solid Waste Management (SWM) is a global issue from its social, environmental, and economic aspects. Poor SWM is one of the significant causes of resource degradation, environmental pollution, and public health problems. In this study, households’ solid waste generation and characterization were determined for selected cities in Ethiopia. Quantitative and qualitative study methods were applied to collect primary and secondary data to assess the household’s MSW generation rate and characterize the waste type's physical composition. The households’ daily MSW generation rates in Bole and Kirkos sub-cities, Addis Ababa, were found to be 0.54 and 0.26 Kg/capita/day, respectively, and the average …

Model Optimization And Applications In Deep Learning, Chengchen Mao

Electrical Engineering Dissertations - Archive

ABSTRACT: Machine learning refers to a machine or an algorithm that draws experience from data. A certain pattern is found to build a model, which is used to solve real problems. Deep learning, an important branch and extension of machine learning, employs a neural network structure containing multiple hidden layers. It learns critical features of the data by combining lower-level features to form more abstract higher-level representations of attribute categories or features. In this dissertation, deep learning network models were applied to sense-through-foliage target detection and extended with Rake structure. The deep learning network models had a large number of …

Environment, Communication And Decision For Multiagent Systems, Lu Zhao

Electrical Engineering Dissertations - Archive

ABSTRACT: Multiagent systems (MAS) are ubiquitous in modern systems and have found broad applications, such as in intelligent transportation systems (ITS). Environment, communication and decision are among the essential components of MAS. The realistic environment in which MAS operates is usually stochastic, and its modeling, identification and estimation are important to consider. The communication in MAS is also critical for decisions. For example, in ITS, to improve travel efficiency and reduce traffic accidents, scheduling schemes for Vehicle-to-Everything (V2X) communication need to be developed. MAS decisions also need to be robust to uncertainties. For example, in mixed-traffic autonomous driving, the decisions …

Effect Of Impurities In Plastic Waste On The Performance Of Plastic Road, Niloy Gupta

Civil Engineering Dissertations - Archive

Plastic waste generation has become a global concern, with a large portion of plastics ending up in landfills. China's recent decision to stop importing waste from various countries, including the USA, has exacerbated the issue of plastic pollution. These plastics, as coming from the household and commercial trash, contain impurity and contamination. This makes the recycling process of plastics more hectic and causes issues in reusing them for other purposes. Impurity and contamination, in fact, is a major issue in material science. Researchers have been studying ways to improve the performance of bituminous pavement, as highways are experiencing increased demand …

Analysis Of The Impact Of Covid-19 On Construction Cost And Schedule Overruns, Nikhitha Adepu

Civil Engineering Dissertations - Archive

The construction industry, renowned for its dynamic nature, encountered unprecedented uncertainties throughout its history. However, the advent of the COVID-19 pandemic served as a powerful catalyst, underscoring the urgent need for a deeper comprehension of the challenges it introduced and their potential implications for the industry's future. While numerous studies have explored this topic, a comprehensive understanding of the specific factors that disrupted the construction sector during the pandemic remains elusive. To bridge this knowledge gap, this study identifies, categorizes, and ranks these challenges, while also proposing effective management strategies to mitigate their detrimental impact on construction projects. To lay …

Dynamic Response Of Cohesive-Frictional Soils Under Thermo-Controlled Constant Water Content Cyclic Simple Shear Testing, Daniel Robert Green

Civil Engineering Dissertations - Archive

Dynamic Response of Cohesive-Frictional Soils Under Thermo-Controlled Constant Water Content Cyclic Simple Shear Testing Daniel R. C. Green The University of Texas at Arlington, 2023 Supervising Professor: Dr. Laureano R. Hoyos A considerable portion of the emerging geothermal infrastructure in the country is located in earthquake prone areas while being supported and/or surrounded by soil deposits located well above the groundwater table. Geotechnical earthquake research in the country, however, continues to be mostly focused on soil response under saturated conditions, especially soil liquefaction phenomena, while most of the work on dynamic response of compacted soils has not taken thermal conditioning …

Cement-Based Nanocomposites With Tunable Electrical And Thermal Conductivity, Myrsini Maglogianni

Civil Engineering Dissertations - Archive

ABSTRACT: While concrete, the most widely used construction material exhibits low electrical and thermal conductivity, it can be engineered at the nanoscale to exhibit energy-related functionalities. This dissertation aims to develop nanoengineered cementitious composites with high electrical conductivity and tunable thermal conductivity to enable energy-related functionalities such as electricity generation and thermal heating capabilities. Highly dispersed nanostructured materials with different intrinsic properties were used to modify the thermal and electrical properties of the developed cementitious composites to enable their thermoelectric (TE) and/or electrothermal (ET) characteristics. One of the objectives of this research was to optimize the electrical-to-thermal energy conversion capability …

Investigation On The Impacts Of Land Subsidence And Urbanization On Flood Inundation In Texas, Han Jiang

Civil Engineering Dissertations - Archive

Floods, being a prevalent and catastrophic natural hazard, have resulted in enormous losses to human lives and properties all over the world. Hence, there is a pressing need to enhance urban resilience and to improve emergency response capacities in order to mitigate the risks posed by flood hazards. Many models have been developed by engineers to simulate and examine the hydrologic and hydraulic responses to the changes within the physical environment. However, there are still knowledge gaps in advancing the understanding of the H&H behavior and hydrodynamics modeling performance. This doctoral study aims to help bridge such gaps via assessing …

An Integrated Algorithm For Automatic Gpr Data Processing For Concrete Rebar Location, Lihong Mao

Civil Engineering Dissertations - Archive

ABSTRACT: Ground Penetrating Radar (GPR) has emerged as a valuable nondestructive testing technique for subsurface imaging and characterization in civil engineering applications. In particular, GPR plays a crucial role in the evaluation of reinforced concrete (RC) structures, enabling the determination of concrete cover thickness and the localization of reinforcement. However, the effectiveness of GPR data analysis is often hindered by inherent challenges, such as unknown time-zero, strong noise, and blurred signals, making the accurate and simultaneous determination of rebar horizontal location and depth a challenging task. This Ph.D. research aims to address these challenges and enhance the accuracy and efficiency …

Digital Twin Enabled Winter Operations Management Through The Integration Of Artificial Intelligence, Sensory Level Data, And Publicly Available Data, Pooya Darghiasi

Civil Engineering Dissertations - Archive

Monitoring real-time information on road conditions, especially during winter storms, is crucial to establishing winter maintenance strategies by the State Departments of Transportation (State DOTs) in the United States. States and local highway agencies allocate substantial resources each year for winter operations to improve road safety during winter storms. However, most weather-related vehicle accidents happen on snowy, slushy, or icy surfaces, leading to a significant number of fatalities and injuries annually. Traditionally, transportation agencies rely on the information provided by Road Weather Information Systems for monitoring road conditions along roadways. However, these systems are costly and only provide estimates at …

Towards Sustainable Additive Manufacturing: Assessment Of Cost, Greenhouse Gas Emission, And Recyclability, Lei Di

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Additive Manufacturing technologies fabricate 3D objects layer by layer following a predesigned CAD model. Owing to the unique layer-wise production method, additive manufacturing offers competitive advantages in comparison with traditional subtractive manufacturing, such as shortened production time, increased design freedom, improved manufacturing capability and complexity, and reduced manufacturing waste. Numerous research studies have been conducted to design, understand, and improve additive manufacturing technologies in order to facilitate the implementation in the supply chain. On the other hand, with the rapid growth of additive manufacturing, sustainability issues that exist on both process level and supply chain level have started to receive …

Applications Of Probability Of Success In The Well Delivery Process To Improve Risk, Opportunity, And Cost Assurance, Romar Alexandra Gonzalez Luis

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Oil and Gas (O&G) well drilling is risky and expensive. The cost of drilling is typically underestimated, and there is little understanding of the certainty or Probability of Success (POS) of achieving the well objectives within the estimated cost. This dissertation presents, for the first time, a publicly available POS Cost method/tool that enables O&G operators to estimate the cost of well drilling substantially more accurately and improve the POS of accomplishing the drilling for the estimated cost. This POS Cost method employs a comprehensive, expert-based assessment of risks and risk mitigations that are incorporated into a Monte-Carlo-based simulation of …

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

Mechanical and Aerospace Student Research - Archive

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

Factors That Determine A University Community’S Satisfaction Levels With Public Transit Services, Muhammad Arif Khan, Ronik Ketankumar Patel, Apurva Pamidimukkala, Sharareh Kermanshachi, Jay Michael Rosenberger, Greg Hladik, Ann Foss

Open Initiatives Grant Funded Publications-Archive

Introduction: Universities and other educational institutions across the United States collaborate with service providers to afford their students, faculty, and staff transit services, such as dedicated buses, on-demand ridesharing, and public transportation. The university community relies on these services, especially in rural and low-density areas without fixed-route transit services. The literature on this topic has a wealth of detailed material about the travel and usage patterns of public transit systems, but it has little information about users’ satisfaction with the transit services provided by universities.

Method: This study focuses on filling this gap by using descriptive statistics and ordered logistic …

Assessment Of Joule Heating Properties Of Various Solder Alloys In Bga Assembly, Jimmy-Bao D. Le

Material Science and Engineering Theses - Archive

The continuing demands for smaller, yet higher performance devices have resulted in many revolutionary changes in device packaging in recent years, including the change in package form factors, structure, and the type of solder alloys used for the assembly. Because solder joints are exposed to various electrical and thermo-mechanical stresses, not only at use condition but also during their process into the assembly, they are prone to failure. Especially concerned in this respect is the current density that the solder joint is subjected to as it determines the level of Joule Heating (JH), thus the solder temperature, significantly affecting the …

Enhancing Microstructure, Composition Homogeneity, And Mechanical Properties In Laser Powder Bed Fused Metallic Alloys: Design, Fabrication, And Evaluation, Bahzad Farhang

Mechanical and Aerospace Engineering Dissertations - Archive

ABSTRACT: Over the past five decades, Nickel-based and Titanium-based alloys have become increasingly popular materials. As the manufacturing industry for these alloys has advanced, the demand for fabricating complex parts with enhanced mechanical properties at elevated temperatures has grown. Laser Powder Bed Fusion (LPBF), one of the most prevalent additive manufacturing techniques, has been employed successfully to produce these alloys. Nonetheless, there is still considerable effort being made to improve the microstructural, compositional, and mechanical properties of LPBF-processed components. In this study, we focused on adjusting the multi-scale microstructure and composition of LPBF-fabricated Nickel-based and Titanium-based alloys. The first objective …

Theoretical And Numerical Analysis Of Thermal Runaway Propagation In Li-Ion Battery Packs, Dhananjay Mishra

Mechanical and Aerospace Engineering Dissertations - Archive

Strategies to prevent or minimize propagation of thermal runaway in a pack of Li-ion cells are critically needed to ensure safe operation, storage and transportation. While significant literature already exists on thermal runaway simulations, several key questions of practical relevance have remained unaddressed. This work presents multi-mode heat transfer simulations to predict the onset and propagation of thermal runaway in a pack of cylindrical Li-ion cells. The impact of inter-cell gap and thermal properties of the interstitial material on onset and propagation of thermal runaway is studied. It is shown that high interstitial thermal conductivity promotes thermal runaway propagation. However, …

Steady State And Transient Analysis Of Heat Transfer In A Porous Fin With Radially Outwards Pressure-Driven Flow, Muhammad Mehdi Abbas

Mechanical and Aerospace Engineering Theses - Archive

Thermal management and energy storage problems often utilize extended surfaces, also known as fins for enhanced heat transfer. Today fins are used in a wide range of devices including but not limited to microelectronic components and large heat exchanger. Traditional fins as well as porous fins with flow orthogonal to fin direction have been subject of past research. There is very few academic literature available on porous fins with pressure driven flow along fin direction. While thermal conduction is usually the dominant mode of heat transfer in a solid fin, the use of porous fins that include advective thermal transport …

Development Of Vortex Box (Vbox) And Vortex Tip (Vtip) Filament Free-Wake Rotor Models, Casey Will Matsler

Mechanical and Aerospace Engineering Theses - Archive

Rotor models span from simple static and first order expressions to high fidelity, numerical computations and across the spectrum each model is good for different purposes. The use of models has improved with time and technological capability but choosing the right model for the task is important. A survey of rotor models is performed to identify a rotor model flexible enough for providing high to moderately high-fidelity results without significantly sacrificing computational time. The model chosen is intended to be for general purposes and applicable across a wide range of operating conditions. From the survey, a blade element rotor model …

Evaluation Of Solder Alloys For Bga Package: A Comparative Reliability Study Using Ansys Computational Analysis, Yashvanth Muthegowda

Mechanical and Aerospace Engineering Theses - Archive

Temperature cycling failure of solder joints in Ball Grid Array (BGA) packages has become a critical issue in electronic manufacturing. This thesis specifically characterizes three different lead-free solder alloys (Pure Indium, SAC-387, and SAC-Q) in BGA solder joints using two different printed circuit board (PCB) thicknesses (1mm and 0.7 mm). The analysis considers the non-uniform temperature distribution caused by the main heat source, the die, and the resulting deformation of the package due to the mismatch in the coefficient of thermal expansion (CTE) between components used in BGA. Finite element (FE) models are created in ANSYS mechanical package environment to …

Advancement Of An Inhouse Aerospace Vehicle Design Synthesis System Through The Introduction Of A Novel Database-Knowledgebase System And By Improving The Geometry And Aerothermodynamic Disciplinary Processes, Samuel Atchison

Mechanical and Aerospace Engineering Theses - Archive

Throughout the years of aerospace vehicle design, the process in which a vehicle is designed has drastically improved from being primarily developed through trial and error, to using sophisticated synthesis systems. While the trial-and-error process had its uses with providing the fundamental knowledge of how aircraft behave and can be designed, the increase in knowledge and technology allowed the possibility of more vehicle configurations to be explored without the need to build each one. This increase should have led to a revolution of vehicle designs, and while there have been some novel ones, it seems that the general design of …

Numerical Modeling Of Damper Configuration And Arrangements For Analysing Thermal Stratification In Modular Air Handling Units, Rohit Antony Raymonds

Mechanical and Aerospace Engineering Theses - Archive

Although air handling units are well established and maturated there are opportunities to optimize and improve the overall thermal and flow performance to reduce the carbon footprint of an air-cooled data center. Airside economization (ASE) arrangement to use cold outdoor air to minimize mechanical cooling energy was substantial progress in minimizing the power usage effectiveness (PUE) for data centers. ASE is an arrangement of ducts and dampers with the necessary controls to meet the cooling requirements. Dampers play a significant role in regulating the mass flow rate of the air and in mixing the two air streams: cold outdoor air, …

Effects Of Metal Organic Frameworks In Polyether Block Amide Elastomer, Joe Alex

Mechanical and Aerospace Engineering Theses - Archive

Metal-organic frameworks (MOFs) are highly porous materials that find extensive applications in gas absorption and separation in recent years. These hybrid materials can be designed with specific pore sizes and voids to selectively filter gases. PEBAX (MV 1074) is a commercially available polyether block amide copolymer generally used in gas separation applications. In this study, we characterize two different MOFs by means of a dispersion study and create a medium for them to be evenly dispersed into the aforementioned copolymer matrix. Polymer composite fibers are extruded using a twin-screw extruder and a winding unit at pre-determined parameters for winding speed …

Impact Of Immersion Cooling On Thermo-Mechanical Properties Of Non-Halogenated Core, Mohan Sai Ramalingam

Mechanical and Aerospace Engineering Theses - Archive

The rise in demand for modern high-power systems, which require fast processing and frequent data storage, has resulted in an exceptional and unprecedented increase in power density and heat generation within data centers. This eventually led to the need for advanced cooling techniques that can address the challenges of managing the heat produced by the data centers. As per Moore's law and Dennard's scaling, the power densities of chips and the heat flux generated by servers are continuously increasing. [1] As a result, the dissipation of heat at the chip level has also increased, posing a significant challenge for thermal …

Study Of Alloy Effect On Electromigration In Sn Solder Alloys, Geng Ni

Material Science and Engineering Dissertations - Archive

This dissertation presents experimental results about the alloy effect on the Electromigration (EM) of Sn in Sn-based binary and ternary alloys. By using cross-stripe configuration, the alloy effect on EM of Sn can be characterized from marker polarity, and the migration of alloy element under EM can be measured from marker front motion. In the dissertation, the mechanism of alloy effect on EM of Sn, “Two-Phase equilibrium”, will be introduced. Electromigration is a phenomenon where metallic atoms are migrated at the direction of electron flow under high current density. In response to the demands for greater speed and smaller size, …

Analyze The Effect Of Urbanization And Development Over The Flow Regime And River Channel Hydraulics Of The Big Bear Creek Channel, Machiraju Pakasasana Kashyap

Civil Engineering Theses - Archive

This thesis focuses on investigating the influence of urbanization and development on flow regime and river channel hydraulics in the Bear Creek watershed, Texas using a comprehensive set of hydrologic and 1D/2D coupled hydraulic model. The Bear Creek watershed, located in North Texas, has experienced rapid urbanization and land development in recent years, raising concerns about the potential impacts on hydrological processes and the hydraulic behavior of the river system. To address these concerns, this research utilizes an integrated modeling approach, combining the HEC-HMS and HEC-RAS software tools, to assess changes in flow rates and simulate their effects on river …

Performance Of Percussion Driven Earth Anchors For Riverbank Slope Stabilization: Comprehensive Laboratory And Field Studies, Natnael Tilahun Asfaw

Civil Engineering Dissertations - Archive

ABSTRACT: The unpredictability of the stability of embankment slopes is a recurring problem that threatens the safety of the traveling public, as it compromises the integrity of the structures built on them. Slopes that undergo seasonal variations of stream flow are of particular concern, as they are usually located under a bridge structure that spans a stream, and the meandering of the stream flow, the seasonal variations of the flow depth, and the velocity in the channel induce scouring and increase the risk of the bridge failing. Departments of transportation have long attempted to address these concerns by designing systems …

Optimization Of Primary Chemical Feed Rates And Application Points At An Existing Potable Water Treatment Plant, Brently Keith Jordan

Civil Engineering Theses - Archive

Due to a major upset in the treatment processes for the Dallas County Park Cities Municipal Utility District caused by a required change in treatment techniques, an optimization study was conducted to find the best treatment strategies for the primary coagulation, flocculation, and settled processes for the treatment plant. A methodology for determining how to optimize jar testing while injecting both ferric sulfate and calcium hydroxide in an almost simultaneous manner was developed, and a large number of jar tests were conducted to determine both the best dosages and the best application points of the two chemicals. As a result …