Engineering Commons^™

Impact Of Particle Surface Charge Heterogeneity On Deposition Onto Flat Surfaces And Transport In Porous Media, Thompson Delon

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Biological and non-biological natural colloids are anisotropic and ubiquitously exist in groundwater. Previously in colloid transport modelling, colloids are assumed to be homogenous for simplification, whether in shape or surface charge. More research has been done to incorporate surface heterogeneity in the transport experiment, i.e., surface charge heterogeneity on collector in column experiment. However, few studies have been done on surface heterogeneity on colloids themselves.

In this dissertation, Janus particles with different surface charge was developed to model surface heterogeneity on colloids. The interaction energy between Janus particle and flat surfaces was analyzed through DLVO simulation. It was discovered that …

In-Service Performance Evaluation And Installation Recommendations For Cable Median Barriers On Non-Continuously Shielded, Divided-Median Kansas Freeways, Nathan Dowler

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The Kansas Department of Transportation (KDOT) installed 7.95 miles of cable median barrier (CMB) along K-10, K-96, and US-75 freeways in 2011 and 2012. In January 2020, KDOT funded a study to determine the in-service performance of its CMBs. In addition, KDOT sought to determine if it was cost-effective to modify guidelines for installing median barriers, which were based on annual daily traffic and median width.

Researchers reviewed every crash within approximately ¼ mile of a CMB installation and extracted crashes which involved a CMB impact. Researchers analyzed the critical details of each CMB crash, with particular emphasis on penetrations, …

Urban Consolidation Center Or Peer-To-Peer Platform? The Solution To Urban Last-Mile Delivery, Qiyuan Deng, Xin Fang, Yun Fong Lim

Research Collection Lee Kong Chian School Of Business

The growing population in cities and booming e-commerce activities create huge demand for urban last-mile delivery, exerting intense pressure on the cities' well-being. To keep congestion and pollution under control, a consolidator can operate an urban consolidation center (UCC) to bundle shipments from multiple carriers before the last-mile delivery. Alternatively, the consolidator can operate a peer-to-peer platform for the carriers to share delivery capacity. We provide guidance for the consolidator to choose between these two business models by comparative analysis. We capture the interactions between the consolidator and carriers using a game-theoretical framework. Under each business model, the consolidator first …

Spectator Proton Detection And Reconstruction In Deep Inelastic D(E,EpS) Scattering, David Payette

Physics Theses & Dissertations

A Radial Time Projection Chamber (RTPC) was designed and installed in Jefferson Lab's Hall B as part of the BONuS12 (Barely Off-shell Nucleon Structure) experiment. The goal of BONuS12 is to accurately measure the structure function of the neutron by scattering 11 GeV electrons and detecting them with the CLAS12 spectrometer. Deuterium gas was used as an effective neutron target, and the new RTPC was used to detect low- momentum spectator protons. Protons follow a curved path in the 5 Tesla solenoid that is part of CLAS12, ionizing the He-CO2 gas in an annular drift region surrounding the target. These …

The Professional Constructor, Full Issue, Volume 46, Number 01

The Professional Constructor

No abstract provided.

Prediction Of Residual Stress And Distortion In Laser Powder Bed Fusion Additive Manufacturing, Bhanuprakash Sairam Kosaraju

Theses and Dissertations

Additive Manufacturing (AM) has its proven advantages to unlock the design space and manufacturing capabilities for complex geometries with lightweights. Distortion is one of the most common defects that occur in Laser Powder Bed Fusion Additive Manufacturing (LPBFAM), which is caused by the significant residual stress during the printing process. This can lead to numerous process iterations to achieve the requisite form and fit tolerances.

In this study, Finite Element (FE) model that utilizes the element birth approach was developed to predict the residual stress and distortion in the LPBFAM process. The methodology leverages a simplified approach where the detailed …

Grafting Based Thermoplastic-Thermoset Bonding For Aerospace Structures, Saurabh Vaidya

Theses and Dissertations

The use of carbon fiber composites is rapidly increasing in the aerospace industry. Fiber reinforced plastic composites can primarily be classified as thermoplastic and thermoset, both offer unique advantages over one another. Thermosets cure at relatively low temperature and in general, are lower priced than thermoplastic composites. However, the cost of autoclave for the curing of thermosets is a major drawback. On the other hand, thermoplastics are showing higher damage tolerance. They can be re-melted and re-consolidated and have the potential to be re-used / recycled. The repair of TP composites is not developed yet. Therefore, both the types attract …

Multi-Robot Coordination With Environmental Disturbances, Adem Coskun

Theses and Dissertations

Multi-robot systems are increasingly deployed in environments where they interact with humans. From the perspective of a robot, such interaction could be considered a disturbance that causes a well-planned trajectory to fail. This dissertation addresses the problem of multi-robot coordination in scenarios where the robots may experience unexpected delays in their movements.

Prior work by Čáp, Gregoire, and Frazzoli introduced a control law, called RMTRACK, which enables robots in such scenarios to execute pre-planned paths in spite of disturbances that affect the execution speed of each robot while guaranteeing that each robot can reach its goal without collisions and without …

Instrumentation And Experimentation Development For Robotic Systems, Tristan Kyzer

Theses and Dissertations

Localization of robotic systems is a necessity for control of robotic systems and often requires the use of costly sensors and equipment onboard the robot or installed within a facility. GPS or GNSS sensors are effective for localizing robots in GPSaccessible environments, but do not work as well in dense urban areas or inside fully enclosed buildings, such as factories or warehouses. Sensors such as LiDAR can be costly and require substantial experience and knowledge to utilize as well as potential changes to infrastructure for use. Computer vision-based localization systems offer potential as a localization solution for various applications. A …

Nondestructive Evaluation And Structural Health Monitoring Of Manufacturing Flaws And Operational Damage In Composite Structures, Robin James

Theses and Dissertations

Advanced composite materials have begun to be used extensively in the manufacturing of aerospace structures. Composite aerospace structures can develop complex types of damages during the manufacturing stages and operational lifetime. This creates an indispensable demand for appropriate nondestructive evaluation (NDE) and structural health monitoring (SHM) methods that are tailored to specific types of damage. This dissertation addresses innovative methods for NDE and SHM of manufacturing flaws and operational damage in composite structures.

For the NDE of manufacturing flaws in carbon fiber reinforced polymer (CFRP) composites, an eddy current testing (ECT) NDE method has been developed by conducting multiphysics modeling …

Rehabilitation Of Timber Piles Using Fiber Reinforced Polymers Analyzed With Acoustic Emission, Rebekah Marie Krol

Theses and Dissertations

Assessing the current state of infrastructure and implementing strengthening or rehabilitation methods on old or damaged members is important to ensure safety and longevity of structures. Non-destructive testing is an important tool for localizing and characterizing damage in structures, especially structures that are more susceptible to damage because of age or environment. In addition to locating inadequate members, it is essential to have a repair technique in place so that the structure can continue to be used in a safe manner.

This study aims to review the use of acoustic emission for evaluating damage obtained in timber piles subjected to …

Role Of Ahr Ligands In Immune Modulation To Suppress Inflammation Through The Regulation Of Microrna And Gut Microbiome, Osama Azeldeen Abdulla

Theses and Dissertations

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor and an environmental sensor that is highly conserved evolutionarily. It was first discovered in the early 1970s for its ability to bind with high affinity to 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), an environmental pollutant and induce a xenobiotic-metabolizing enzyme known as aryl hydrocarbon hydroxylase (AHH). AhR was shown to regulate TCDD-mediated toxicity against a variety of tissues including the immune system. More recently, AhR has been characterized as key regulator of the immune system, specifically the differentiation of T cells. Also, several AhR ligands have been characterized in addition to TCDD such as …

Temperature Dependence Of Electroluminescence And Current-Voltage Characteristics Of Arrays Of Deep Ultraviolet Algan Micropixel Led, Dhruvinkumar Prakashchandra Patel

Theses and Dissertations

III-Nitride based deep ultraviolet (DUV) light emitting diodes are non-toxic light sources that are highly desirable to replace current mercury lamp-based technology for air and water purification, surface and object disinfection, and sterilization. In the present. By freezing out defect related conduction pathways at temperatures less than 50K, the external quantum efficiency (EQE) of an interconnected array of 1,296 AlGaN DUV micropixels is improved by 4 times, underscoring the importance of defect management. Assuming a current injection efficiency (CIE) of 100% and considering that the light extraction efficiency (LEE) is constant with temperature, the 4-fold increase in the EL signal …

An Acoustic Emission And Artificial Intelligence Approach To Structural Health Monitoring For Aerospace Application, Joseph Chandler Garrett

Theses and Dissertations

In the area of aerospace and other applications, structural health monitoring (SHM) has been a significant and growing area of research in recent years. Throughout the operational life of aerospace structures, various damage scenarios may manifest, and it is of great concern to the aerospace community to develop methodologies for detecting and assessing these damage scenarios. In this paper, fundamental research on the use of the acoustic emission (AE) approach to SHM for fatigue crack growth is presented. In general, the AE approach to SHM and non-destructive evaluation (NDE) involves the sensing of ultrasonic Lamb waves propagating through a structure. …

Discovery And Investigation Of Ammonia Decomposition Catalysts, Katherine Mccullough

Theses and Dissertations

Liquid ammonia can be used as a hydrogen transportation and generation source for use in PEM fuel cells. Current Ru catalysts for ammonia decomposition contain high loadings of Ru and require reaction temperatures at or above 550°C to attain equilibrium conversion. For on-site hydrogen generation, it is of interest to combine hydrogen generation from ammonia decomposition directly with PEM fuel cells. For this occur, operating temperatures need to be considerably lowered and effluent concentrations of ammonia need to be minimized to avoid poisoning of the membrane. Therefore, it is of interest to develop a low-cost catalyst that exhibits high activity …

Mitigating Corrosion And Enhancing Energy Density Of Zinc-Based Anodes In Primary And Secondary Aqueous Batteries, Ehsan Faegh

Theses and Dissertations

Today Lithium-ion (Li-ion) batteries are the most-emphasized battery technology among the many different battery systems in the market. However, due to their high cost (especially for electric vehicle applications), flammability and toxicity, the development of inexpensive and safer alternative battery chemistries has been the focus of a significant amount of recent research. Among various battery chemistries, Aluminum-based (Al-based) and Zinc-based (Zn-based) batteries have been touted as promising options to compete with Li-ion batteries. However, the practical realization of Al battery chemistries has been difficult over a long period of time (170 years) due to a number of fundamental and intrinsic …

Separate Effects Tests For Studying Thermal Gradient Driven Cracking In Uo2 Pellets Undergoing Resistive Heating, Sobhan Patnaik

Theses and Dissertations

A variety of normal operation and accident scenarios can generate thermal stresses large enough to cause cracking in light-water reactor (LWR) fuel pellets. Cracking of fuel pellets can lead to reduced heat removal, larger centerline temperatures, and localized stress in cladding, all of which impact fuel performance. It is important to understand the temperature profile on the pellet before and after cracking to improve cracking models in fuel performance codes such as BISON. However, in reactor observation and measurement of cracking is very challenging owing to the harsh environment and design of fuel rods.

Recently, a state-of-the-art experimental pellet cracking …

Degradative Processes Of Commercial And Next-Generation Lithium-Ion Battery Materials, Benjamin Ng

Theses and Dissertations

The work embodied in this thesis bridges the gap between modern and next-generation Li-ion batteries (LIBs). First, a detailed study of the complex interfacial interactions (e.g. electrode/electrolyte, particle/particle, particle/solid-electrolyte interphase) in existing LIBs (graphite anode, Li(Ni_0.5Mn_0.3Co_0.2)O_2 cathode) are investigated and then used to develop strategies for safer, more energy-dense, and more durable electrode materials (i.e. tailored hybrid materials). The first portion of this thesis focuses heavily on decoupling the complex thermodynamics, reaction kinetics, and mass transport properties in commercially available LIBs. This thesis includes a detailed investigation into the operating parameter space for LIBs, including temperature (-30^oC to +52^oC), state-of-charge …

Experimental Investigation Of Spray Cooling Integrated With A Modified Vapor Compression Refrigeration System Using Several Refrigerants, Nabeel Mukhlif Abdulrazzaq

Theses and Dissertations

Spray cooling has gained increasing interest over the last three decades due to its high thermal performance as a direct cooling technique. Researchers are investigating spray cooling in thermal management systems for electronic applications, particularly focusing on the use of dielectric fluids including FC-72, FC-87, ammonia, and refrigerants such as R113 and R134a. Their studies indicate that the usage of dielectric fluids as a working fluid in spray cooling systems is promising and has significant thermal performance enhancement, which is suitable for a wide range of electronic applications. However, several deficiencies have been identified with the working fluids studied thus …

Physical Modeling Of Backward Erosion Piping Phenomenon In A Geotechnical Centrifuge, William Fernando Ovalle Villamil

Theses and Dissertations

Backward erosion piping is a mechanism of internal erosion that has been widely recognized as a potential hazard for water-retaining structures, such as dams and levees, that are founded on granular materials. Backward erosion piping initiates toward the downstream zone of the structure by the concentration of flow at an exit point acting as drainage, which leads to a localized loosening of the soil and eventually to a continuous migration of grains from the foundation following a piping path pattern. Such piping path extends backward toward the impoundment once a certain critical hydraulic condition is met, resulting in the loss …

Mechanism Of Therapeutic Efficacy Of New Drugs In Glioblastoma, Firas Hameed Khathayer

Theses and Dissertations

Glioblastoma is the most malignant and prevalent brain tumor in adults. It can grow and spread quickly causing harm to brain health. The deregulation of epigenetic mechanisms is considered the main agent in the developing of GBM. One of the enzymes involved in epigenetic alternation and cancer development are histone deacetylases enzyme (HDAC) by removal acetyl group from histone and create condensed chromatin that suppresses transcription gene to histone and non-histone proteins involved in tumorigenesis. Histone deacetylase inhibitors (HADCi) are the most common therapeutic methods for many types of cancer treatments. In the present study, we used relative HDAC inhibitor …

Failure Of Ultra-High Molecular Weight Polyethylene Yarns (Uhmpwe) Under Transverse Loading Using Different Indenter Geometries, Karan Shah

Theses and Dissertations

Ultra-high molecular weight polyethylene (UHMWPE) Dyneema® SK-76 fibers are widely used in personnel protection systems. Transverse ballistic impact onto these fibers results in complex multiaxial deformation modes such as axial tension, axial compression, transverse compression, and transverse shear. Previous impact studies on high performance yarns and quasi-static transverse loading of single fibers using different indenter geometries show premature failure of yarns and single fiber caused by the degradation of tensile failure strain due to the presence of such multi-axial deformation modes. However, there is a dearth of failure criterion in the literature for ballistic applications that considers the contribution of …

Nano-Engineered High-Performance Copper-Water Heat Pipes, Ahmed A. Abdulshaheed

Theses and Dissertations

Recently, heat pipes have gained an exceptional reputation as passive systems. They have become an attractive choice for many engineering applications due to their simple design, high rate of heat transfer, low weight, and low cost of maintenance [1]. A Heat pipe consists of a vacuumed shell filled partially with a compatible working fluid. Three main sections comprise a heat pipe: evaporator, adiabatic, and condenser section. The heat pipe utilizes the principle of evaporation and condensation for operations, i.e., the phase change of working fluid. Heat pipe allows high heat rates to transfer over considerable lengths with minimum temperature differences …

An Injectable Thermosensitive Hydrogel Potentially Used For Wound Dressing With Self-Adhesive Properties, Yunxiu Qiu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Wound healing is a complex process, and different kinds of materials are tried to achieve rapid healing. Among them, hydrogel is one of the best candidates for would dressing due to its distinctive properties, such as high biocompatibility, flexibility, and sensitivity to physiological environments. Injectable hydrogels can be facilely delivered in vivo without massive impairment to the body, as no surgical incision is needed for hydrogel embedment. This is highly consistent with the need of minimal invasion on human body. Multiple stimuli could be applied to achieve its injectability, including pH, temperature, light, ions in body fluids. Thermosensitive hydrogel is …

Mems 411: Fast Pill Cutter, Andrew Brown, Isaac Sasser, Aaron Manuel, Quan Chau

Mechanical Engineering Design Project Class

This design project attempted to create a new pill-cutting device to help pharmacy technicians split pills quickly, precisely, and safely. The product was intended to occupy a competitive niche with current devices on the market, prioritizing increased cutting speed with potentially greater cost.

Mems 411: Ground Work Station Design Project, Jakub A. Gawedzki, Mark H. Wood, John B. Campoverde

Mechanical Engineering Design Project Class

Researchers from Washington University had requested us to design and develop a ground work station that allows them to work comfortable in the field for our senior design class.

Mems 411; Ground Work Station, Samuel Wille, Daniel Renbaum-Koss

Mechanical Engineering Design Project Class

This project aims to design a support mechanism for ecological field researchers who interact with plants and other samples from the forest floor for long periods. The design aims to recreate the functionality of bending over for long periods of time, while protecting the backs, hips and knees.

Mems 411: Lift Demonstration, Dean Ryan-Simmons, Marketa Riley, Puja Chhetri

Mechanical Engineering Design Project Class

A portable lift demonstration was requested to get children interested and thinking about what happens with fluid movement. The demonstration had size and weight requirements, which were both met. Accuracy of lift force representation was not requested, but simple force and flow visualizations were required. The demonstration had variable wind speeds, and showed the change in force with change in angle of attack.

Mems 411: Portable Ground Work Station - Group C, Samantha Hudson, Valeria Pinedo Chipana, Valentina Harding, Luis Acosta

Mechanical Engineering Design Project Class

Build a ergonomic, portable, and weather resistant ground work station for members of the department of Biology to use during field research.

Mems 411: Lost Grains Winnower, Seth Jack, Matthew Finer, Alex Maggioni, Kristian Nilsen

Mechanical Engineering Design Project Class

This project involved designing an upgrade for the grain winnower in Dr. Mueller’s anthropology lab at Washington University in St. Louis. A winnower is a device that separates chaff from usable grain after harvesting and threshing. Many such devices exist, from industrial-scale winnowers sorting high volumes of grain to personal coffee bean winnowers. However, the constraints of the lab space and the specialized nature of the grain being winnowed presented specific constraints. An interview with Dr. Mueller was necessary to determine a ranked list of needs for use in the final product. After creating these rankings, a mock-up was used …