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Articles 6901 - 6930 of 8951
Full-Text Articles in Engineering
A Student-Centered Learning Approach To Design For Manufacturability: Meeting The Needs Of An Often- Forgotten Customer, Jay R. Goldberg, David Rank
A Student-Centered Learning Approach To Design For Manufacturability: Meeting The Needs Of An Often- Forgotten Customer, Jay R. Goldberg, David Rank
Biomedical Engineering Faculty Research and Publications
A hands-on learning module was implemented at Marquette University in 2012 to teach biomedical engineering students about basic manufacturing processes, lean manufacturing principles, and design for manufacturability. It incorporates active and student-centered learning as part of in-class assembly line simulations. Since then, it has evolved from three class periods to five. The module begins with two classroom presentations on manufacturing operations and electronics design, assembly, and testing. Students then participate in an in-class assembly line simulation exercise where they build and test an actual product per written work instructions. They reflect on this experience and suggest design and process changes …
Strengthening Of Reinforced Masonry Walls Subjected To Out-Of-Plane Pseudo-Static Cyclic Load Using Advanced Composite, Zuhair Al-Jaberi
Strengthening Of Reinforced Masonry Walls Subjected To Out-Of-Plane Pseudo-Static Cyclic Load Using Advanced Composite, Zuhair Al-Jaberi
Doctoral Dissertations
"A number of researchers have conducted experimental tests on unreinforced masonry walls (URM) strengthened with advanced composite materials. Consequently, the strengthening design guidelines are limited in their scope to URM. This research aimed to investigate the behavior of reinforced masonry walls strengthened with advanced composite and subjected to out-of-plane pseudo-static cyclic load. Experimental and analytical studies were conducted to evaluate the performance of different techniques such as near surface mounted (NSM) and externally bonded (EB) fiber reinforced polymer (FRP) with epoxy resin, in addition to NSM with cementitious adhesive and fiber reinforced cementitious material (FRCM). The experimental part included three …
Deep Learning And Localized Features Fusion For Medical Image Classification, Haidar A. Almubarak
Deep Learning And Localized Features Fusion For Medical Image Classification, Haidar A. Almubarak
Doctoral Dissertations
"Local image features play an important role in many classification tasks as translation and rotation do not severely deteriorate the classification process. They have been commonly used for medical image analysis. In medical applications, it is important to get accurate diagnosis/aid results in the fastest time possible.
This dissertation tries to tackle these problems, first by developing a localized feature-based classification system for medical images and using these features and to give a classification for the entire image, and second, by improving the computational complexity of feature analysis to make it viable as a diagnostic aid system in practical clinical …
Process Simulation And Experimental Investigation Of Biofuel Production In A High Rate Anaerobic Digestion Process, Haider Al-Rubaye
Process Simulation And Experimental Investigation Of Biofuel Production In A High Rate Anaerobic Digestion Process, Haider Al-Rubaye
Doctoral Dissertations
"The non-hazardous waste management hierarchy of the US EPA calls for “Reduce, Reuse, and Recycle” (or the three R’s) of wastes. The anaerobic digestion process is one of the most important methods that used to treat the wastes and at the same time generate energy out of it. The anaerobic digestion process generates a mixture of methane and carbon dioxide gases which is known as biogas.
The biogas composition is about 50-70% methane and 10-30% of carbon dioxide and trace amount of other gases like hydrogen and hydrogen sulfide. This biogas can be used in power generation, heating systems and …
Imaging And Mitigating Karst Features, Kenneth Joseph Bansah
Imaging And Mitigating Karst Features, Kenneth Joseph Bansah
Doctoral Dissertations
"Over the last three years, a comprehensive subsurface investigation that combines both conventional and geophysical techniques has been conducted near Springfield in southwest Missouri, United States. This study, which forms part of the comprehensive subsurface investigation, aimed to (1) image and characterize the subsurface, (2) map variations in engineering properties of soil/rock, (3) map variable depth to top of rock, (4) explore the utility of the geophysical techniques, (5) determine the factors contributing to karst processes, and (6) propose karst mitigation. Electrical resistivity tomography (ERT) and multichannel analysis of surface waves (MASW) were employed for the acquisition of subsurface geophysical …
Laser Foil Printing And Surface Polishing Processes, Chen Chen
Laser Foil Printing And Surface Polishing Processes, Chen Chen
Doctoral Dissertations
"A foil-based additive manufacturing technology for fabricating metal parts, called Laser Foil Printing (LFP), was proposed and developed in this dissertation. The manufacturing sub-processes comprising the LFP technology were comprehensively studied, which include the laser spot welding of foil, laser raster-scan welding of foil, laser cutting of foil, and laser polishing processes. The fabricated free-form parts were demonstrated and own better mechanical properties (micro hardness and tensile strength) than the raw material, because of the rapid-cooling process of laser welding. The full and strong bond between layers was formed by the laser welding process, with no micro-cracks or pores observed. …
Geomechanical Characterizations And Correlations To Reduce Uncertainties Of Carbonate Reservoir Analysis, Farqad Hadi
Geomechanical Characterizations And Correlations To Reduce Uncertainties Of Carbonate Reservoir Analysis, Farqad Hadi
Doctoral Dissertations
"Although carbonate reservoirs hold a wealth of hydrocarbon, they are among the most difficult types of reservoirs to be characterized. Carbonate reservoirs by nature have complex depositional environments and diagenetic processes in which brittle, ductile, fractured rocks, and vugular pores may all exist within small interval. This huge variance in the rock mechanical properties can cause challenges in the reservoir's development, especially in applications related to geomechanics.
The main objective of this research is to geomechanically characterize and correlate the carbonate mechanical properties with their petrophysical properties. A comprehensive review for the geomechanical-petrophysical properties of carbonates was conducted from previous …
Gis-Based Spatial Analysis Coupled With Geophysical Imaging To Identify And Evaluate Factors That Control The Formation Of Karst Sinkholes In Southwestern Missouri, Shishay T. Kidanu
Gis-Based Spatial Analysis Coupled With Geophysical Imaging To Identify And Evaluate Factors That Control The Formation Of Karst Sinkholes In Southwestern Missouri, Shishay T. Kidanu
Doctoral Dissertations
"Sinkholes are inherent features of the karst terrain underlying much of Greene County, Missouri. These features present hazards and engineering challenges to existing infrastructure unknowingly constructed on a seemingly benign ground surface. The primary objective of this research was to investigate the physical processes chiefly responsible for triggering the seemingly random distribution of sinkholes in the study area. This research employed an integrated approach encompassing regional scale GIS-based spatial analyses and site-specific geophysical data. GIS-based spatial analysis was employed to identify significant physical factors that appeared to influence the formation and distribution of sinkholes. Seven out of the twelve most …
Service Response And Evaluation Of Prestressed Concrete Bridges Through Load Testing, Eli Saul Hernandez Ramos
Service Response And Evaluation Of Prestressed Concrete Bridges Through Load Testing, Eli Saul Hernandez Ramos
Doctoral Dissertations
"During the last two decades, self-consolidating concrete (SCC) has emerged as an alternative to produce structures with longer life expectancy. Despite the advantages that come with using SCC, there are some concerns related to its structural and serviceability response. The effect of the larger paste content and smaller coarse aggregate size is of particular interest because this combination may inhibit the development of the SCC's target mechanical properties. Field tests are an effective method to monitor the service response of infrastructure. In addition, field tests have largely confirmed reserves of strength capacity in existing bridges despite their visual condition and …
Analysis Of Dc Microgrids As Stochastic Hybrid Systems, Jacob Andreas Mueller
Analysis Of Dc Microgrids As Stochastic Hybrid Systems, Jacob Andreas Mueller
Doctoral Dissertations
"A modeling framework for dc microgrids and distribution systems based on the dual active bridge (DAB) topology is presented. The purpose of this framework is to accurately characterize dynamic behavior of multi-converter systems as a function of exogenous load and source inputs. The base model is derived for deterministic inputs and then extended for the case of stochastic load behavior. At the core of the modeling framework is a large-signal DAB model that accurately describes the dynamics of both ac and dc state variables. This model addresses limitations of existing DAB converter models, which are not suitable for system-level analysis …
Advancement In Thermal Energy Storage Using Phase Change Materials, Rami Mohammad Reda Saeed
Advancement In Thermal Energy Storage Using Phase Change Materials, Rami Mohammad Reda Saeed
Doctoral Dissertations
"The dissertation is intended to study the fundamental physical behavior of phase change materials (PCMs) and provide a comprehensive overview of the state of the art in their design and applications for thermal energy storage. Standard, predictive and thermodynamic models were presented to develop new PCM eutectic mixtures in a more scientific design approach. As new eutectic PCMs were developed, further research efforts were initiated to develop functionalized PCMs with enhanced thermal and physical properties to create the next generation of PCMs. Further efforts have been expanded to review several high-temperature PCM candidates with phase transition temperatures in the range …
Investigation Of Microstructure And Mechanical Properties By Direct Metal Deposition, Jingwei Zhang
Investigation Of Microstructure And Mechanical Properties By Direct Metal Deposition, Jingwei Zhang
Doctoral Dissertations
"Microstructure and properties of Direct Metal Deposition (DMD) parts are very crucial to meeting industrial requirements of parts quality. Prediction, and control of microstructure and mechanical properties have attracted much attention during conventional metal manufacturing process under different conditions. However, there is few investigations focused on microstructure simulation and mechanical properties control under different process parameters during DMD process. This dissertation is intended to develop a multiscale model to investigate Ti6Al4V grain structure development and explore Ti6Al4V based functionally graded material (FGM) deposit properties during DMD process. The first research topic is to investigate and develop a cellular automaton-finite element …
A Multiple Scattering Method To Study The Cable Harness Inside A Vehicle Shell, Yansheng Wang
A Multiple Scattering Method To Study The Cable Harness Inside A Vehicle Shell, Yansheng Wang
Doctoral Dissertations
"This dissertation contains three major parts. In the first part, a generalized multi-conductor transmission line (GMTL) method is proposed to model a cable harness. In the GMTL method, all wires of the cable harness take the infinity as the reference. In such a way, the GMTL method takes into account not only the transmission-line mode but also the antenna-mode current on the cable harness. Further, by employing the GMTL method and the mixed-potential integral equations (MPIE) method in a multiple scattering (MS) procedure, it enables an efficient and accurate approach to evaluate the current distribution on a cable harness with …
Guayule Plant Extracts As Binder Modifiers In Flexible (Asphalt) Pavement Mixtures, Steven Michael Lusher
Guayule Plant Extracts As Binder Modifiers In Flexible (Asphalt) Pavement Mixtures, Steven Michael Lusher
Doctoral Dissertations
"The guayule (pronounced, 'why-YOO-lee') plant is a woody perennial shrub that is native to areas of the southwestern United States and northern Mexico, and is a well-documented source of high-quality natural rubber. The U.S. needs a domestic source of natural rubber to allay concerns about its future availability. Cultivation of guayule in North America has been attempted many times since the late 19th century, and companies, including major tire manufacturers, are again investing in guayule research. However, full-scale commercialization of guayule rubber needs established markets for the two basic by-products of guayule rubber extraction: the plant resins (primarily non-rubber compounds) …
Research On Additive Manufacturing Of Metallic Glass Alloy, Yiyu Shen
Research On Additive Manufacturing Of Metallic Glass Alloy, Yiyu Shen
Doctoral Dissertations
"The required rapid cooling has limited the dimension of the Bulk Metallic glasses (BMGs) produced by traditional method, and hence has seriously limited their applications, despite their remarkable mechanical properties. In this present project, a detailed study is conducted on the methodology and understanding of manufacturing large Zr- based metallic glass part by laser based additive manufacturing technology, which breaks the size limitation. The first research issue proposes and develops a new additive manufacturing technology, named Laser-Foil-Printing (LFP). Sheet foils of LM105 (Zr52.5Ti5Al10Ni14.6Cu17.9 (at. %)) metallic glass are used as feed …
Mitigation Of Environmental Hazards Of Sulfide Mineral Flotation With An Insight Into Froth Stability And Flotation Performance, Muhammad Badar Hayat
Mitigation Of Environmental Hazards Of Sulfide Mineral Flotation With An Insight Into Froth Stability And Flotation Performance, Muhammad Badar Hayat
Doctoral Dissertations
"Today's major challenges facing the flotation of sulfide minerals involve constant variability in the ore composition; environmental concerns; water scarcity and inefficient plant performance. The present work addresses these challenges faced by the flotation process of complex sulfide ore of Mississippi Valley type with an insight into the froth stability and the flotation performance. The first project in this study was aimed at finding the optimum conditions for the bulk flotation of galena (PbS) and chalcopyrite (CuFeS₂) through Response Surface Methodology (RSM). In the second project, an attempt was made to replace toxic sodium cyanide (NaCN) with the biodegradable chitosan …
Electrodeposited Semiconductor Nanostructures & Epitaxial Thin Films For Flexible Electronics, Naveen Kumar Mahenderkar
Electrodeposited Semiconductor Nanostructures & Epitaxial Thin Films For Flexible Electronics, Naveen Kumar Mahenderkar
Doctoral Dissertations
"Single-crystal Si is the bedrock of semiconductor devices due to the high crystalline perfection which minimizes electron-hole recombination, and the dense native silicon oxide which minimizes surface states. To expand the palette of electronic materials beyond planar Si, an inexpensive source of highly ordered material is needed that can serve as an inert substrate for the epitaxial growth of grain boundary-free semiconductors, photonic materials, and superconductors. There is also a need for a simple, inexpensive, and scalable fabrication technique for the growth of semiconductor nanostructures and thin films. This dissertation focuses on the fabrication of semiconducting nanowires (polycrystalline Ge & …
Machine Learning Techniques Implementation In Power Optimization, Data Processing, And Bio-Medical Applications, Khalid Khairullah Mezied Al-Jabery
Machine Learning Techniques Implementation In Power Optimization, Data Processing, And Bio-Medical Applications, Khalid Khairullah Mezied Al-Jabery
Doctoral Dissertations
"The rapid progress and development in machine-learning algorithms becomes a key factor in determining the future of humanity. These algorithms and techniques were utilized to solve a wide spectrum of problems extended from data mining and knowledge discovery to unsupervised learning and optimization. This dissertation consists of two study areas. The first area investigates the use of reinforcement learning and adaptive critic design algorithms in the field of power grid control. The second area in this dissertation, consisting of three papers, focuses on developing and applying clustering algorithms on biomedical data. The first paper presents a novel modelling approach for …
The Utility Of Geophysical Techniques To Image The Shallow Subsurface In Karst Areas In Missouri, Nathainail Bashir
The Utility Of Geophysical Techniques To Image The Shallow Subsurface In Karst Areas In Missouri, Nathainail Bashir
Doctoral Dissertations
"This dissertation is composed of three papers, which are focused on the utility of geophysical techniques to imaging the shallow subsurface in karst areas in Missouri.
In the first paper, ground penetrating radar (GPR) and time domain electromagnetic metal detector (TDEM-MD) methods were effectively deployed in an investigation of the cemetery with the intent of locating unmarked graves. The outcome of this study is to expand the knowledge of GPR and TDEM-MD methods, to locate unmarked graves in cemeteries. The study concluded that the GPR method is superior than TDEM-MD to locate buried caskets in cemetery investigations.
In the second …
Multi-Scale Investigation Of Microstructure, Fiber-Matrix Bond, And Mechanical Properties Of Ultra-High Performance Concrete, Zemei Wu
Doctoral Dissertations
"The main objective of this study is to provide new insights into enhancing fiber-matrix bond and mechanical properties of ultra-high performance concrete (UHPC). Three main strategies were investigated: 1) use of supplementary cementitious materials; 2) use of nano-particles; and 3) use of deformed fibers. A multi-scale investigation involving the evaluation of non-fibrous UHPC mortar phase (matrix), fiber-matrix interface phase, and then UHPC composite material was undertaken to determine microstructural characteristics, fiber bond to matrix, and key mechanical properties of the UHPC matrix and UHPC. Test results indicate that the incorporation of 10%-20% silica fume effectively improved the fiber-matrix bond and …
Computational Design And Numerical Analyses Of Thermal-Hydraulics In A Pwr-Type Small Modular Nuclear Reactor, Vivek Murlidhar Rao
Computational Design And Numerical Analyses Of Thermal-Hydraulics In A Pwr-Type Small Modular Nuclear Reactor, Vivek Murlidhar Rao
Doctoral Dissertations
"This dissertation focuses on computational design of a PWR-type small modular nuclear reactor (SMR), and analysis of coolant thermal-hydraulics during steady-state operation. Physical design of the SMR is based on the existing AP-1000 and Small Modular Reactor designs by Westinghouse Nuclear.
The first paper discusses a two-stage simulation of turbulent flow in the lower plenum of the RPV. In the first stage, four time-dependent Reynolds-Averaged Navier-Stokes (RANS) based turbulence models were used to simulate turbulent flow, compare predictions and identify an appropriate turbulence model. In the second stage, the selected turbulence model was once again used to simulate flow on …
Development And Management Of Advanced Batteries Via Additive Manufacturing And Modeling, Jie Li
Development And Management Of Advanced Batteries Via Additive Manufacturing And Modeling, Jie Li
Doctoral Dissertations
"The applications of Li-ion batteries require higher energy and power densities, improved safety, and sophisticated battery management systems. To satisfy these demands, as battery performances depend on the network of constituent materials, it is necessary to optimize the electrode structure. Simultaneously, the states of the battery have to be accurately estimated and controlled to maintain a durable condition of the battery system. For those purposes, this research focused on the innovation of 3D electrode via additive manufacturing, and the development of fast and accurate physical based models to predict the battery status for control purposes. Paper I proposed a novel …
Data Driven Decision Making Tools For Transportation Work Zone Planning, Samareh Moradpour
Data Driven Decision Making Tools For Transportation Work Zone Planning, Samareh Moradpour
Doctoral Dissertations
"This research provides tools and methods for integrating stakeholder input and crash data analytics to better guide transportation engineers in effective work zone design and management. Three key contributions are presented: the importance of stakeholder input in traffic management strategies, application of data mining and pattern recognition to identify high-risk drivers in work zones, and the use of multinomial logistic regression (MLR) as a tool to understand key findings from historic crash data. Work zone signage is mandated by the Manual on Uniform Traffic Control Devices (MUTCD), but the current configurations are often criticized by the driving public and state …
Limiting Key Drilling Parameters To Control Mud Losses In Basra's Oil Fields, Iraq, Abo Taleb Tuama Al-Hameedi
Limiting Key Drilling Parameters To Control Mud Losses In Basra's Oil Fields, Iraq, Abo Taleb Tuama Al-Hameedi
Doctoral Dissertations
"Wells in Basra's oil fields are highly susceptible to lost circulation problems when drilling through the Dammam, Hartha, and Shuaiba formations. Drilling engineers are challenged to select the optimum value for key drilling parameters such as ECD, Yp, MW, WOB, ROP, and RPM to mitigate mud losses in these formations. Many of these drilling parameters are inter-related and the overall impact of changing key parameters require extensive drilling experience and study. A multi-regression analysis was performed on mud loss event data for more than 300 wells drilled in Basra's oil fields. From this analysis, a model was developed to predict …
Sensitivity Of Rheological Properties Of Cement Paste With Scc Consistency, Azadehalsadat A. Asghari
Sensitivity Of Rheological Properties Of Cement Paste With Scc Consistency, Azadehalsadat A. Asghari
Doctoral Dissertations
"Robustness, which is defined as the capacity of a mixture to tolerate small variations in constituent elements, mixing parameters or temperature that are inevitable with production at any significant scale, is a key property to expand the practical implementation of self-consolidating concrete (SCC). At the first step, the effect of different amount of water, amount of superplastizer, mixing time, mixing speed and the addition time of superplastizer on the rheological properties of cement pastes with SCC consistency, has been evaluated. Two different SCC mix design concepts, the powder-type and VMA-type were selected for this research. The results show that the …
Advanced Topologies Of High-Voltage-Gain Dc-Dc Boost Converters For Renewable Energy Applications, Ahmad Alzahrani
Advanced Topologies Of High-Voltage-Gain Dc-Dc Boost Converters For Renewable Energy Applications, Ahmad Alzahrani
Doctoral Dissertations
This dissertation proposes several advanced power electronic converters that are suitable for integrating low-voltage dc input sources, such as photovoltaic (PV) solar panels, to a high voltage dc bus in a 200 - 960 V dc distribution system. The proposed converters operate in the continuous conduction mode (CCM) and offer desirable features such as low-voltage stresses on components, continuous input currents, and the ability to integrate several independent dc input sources. First, a family of scalable interleaved boost converters with voltage multiplier cells (VMC) is introduced. Several possible combinations of Dickson and Cockcroft-Walton VMCs are demonstrated and compared in terms …
Direct Numerical Simulation Of Pressure Fluctuations Induced By Supersonic Turbulent Boundary Layers, Chao Zhang
Direct Numerical Simulation Of Pressure Fluctuations Induced By Supersonic Turbulent Boundary Layers, Chao Zhang
Doctoral Dissertations
"Direct Numerical Simulations are used to generate a database of high-speed zero-pressure-gradient turbulent boundary layers developing spatially over a flat plate with nominal freestream Mach number ranging from 2:5 to 14 and wall-to-recovery temperature ranging from 0:18 to 1:0. The flow conditions of the DNS are representative of the operational conditions of the Purdue Mach 6 quiet tunnel, the Sandia Hypersonic Wind Tunnel at Mach 8, and the AEDC Hypervelocity Tunnel No. 9 at Mach 14. The DNS database is used to gauge the performance of compressibility transformations, including the classical Morkovin's scaling and strong Reynolds analogy as well as …
Multitarget Tracking And Terrain-Aided Navigation Using Square-Root Consider Filters, James Samuel Mccabe
Multitarget Tracking And Terrain-Aided Navigation Using Square-Root Consider Filters, James Samuel Mccabe
Doctoral Dissertations
"Filtering is a term used to describe methods that estimate the values of partially observed states, such as the position, velocity, and attitude of a vehicle, using current observations that are corrupted due to various sources, such as measurement noise, transmission dropouts, and spurious information. The study of filtering has been an active focus of research for decades, and the resulting filters have been the cornerstone of many of humankind's greatest technological achievements. However, these achievements are enabled principally by the use of specialized techniques that seek to, in some way, combat the negative impacts that processor roundoff and truncation …
High Temperature Polymer Composites Using Out-Of-Autoclave Processing, Sudharshan Anandan
High Temperature Polymer Composites Using Out-Of-Autoclave Processing, Sudharshan Anandan
Doctoral Dissertations
"High performance polymer composites possess high strength-to-weight ratio, corrosion resistance, and have design flexibility. Carbon/epoxy composites are commonly used aerospace materials. Bismaleimide based composites are used as a replacement for epoxy systems at higher service temperatures. Aerospace composites are usually manufactured, under high pressure, in an autoclave which requires high capital investments and operating costs. In contrast, out-of-autoclave manufacturing, specifically vacuum-bag-only prepreg process, is capable of producing low cost and high performance composites. In the current study, out-of-autoclave processing of high temperature carbon/bismaleimide composites was evaluated. The cure and process parameters were optimized. The properties of out-of-autoclave cured laminates compared …
Modeling And Characterization Of Thermo-Oxidative Behavior Of Bismaleimide Composites, Rafid Muhammad Hussein
Modeling And Characterization Of Thermo-Oxidative Behavior Of Bismaleimide Composites, Rafid Muhammad Hussein
Doctoral Dissertations
"High-temperature polymer matrix composites (HTPMCs) are susceptible to thermo-oxidation, which accelerates the composites' degradation and reduces the service life. Mechanical properties of HTPMCs deteriorate due to coupled thermo-oxidation and cross-linking mechanisms. Bismaleimides (BMIs) are commonly used high-temperature resins for aerospace applications. This work presents the viability of using experimental weight loss to model the spatial distribution of oxidation when the oxidized polymer matrix is not discernible. Three tasks are introduced: (1) Anisotropic oxidation prediction using optimized weight loss behavior of bismaleimide composites, (2) A multi-scale modeling of thermo-oxidative effects on the flexural behavior of cross-ply bismaleimide composites, and (3) Thermo-oxidative …