Engineering Commons^™

Structural Evolution During Synthesis And Annealing Of Platinum-Nickel Bimetallic Nanoparticles, Xiner Lu

All Theses

In the past years, there has been an increasing interest in synthesizing Pt alloy nanocrystals to achieve high catalytic performance for energy-related applications. Pt-Ni nanoparticles (NPs) have shown high electrocatalytic activity for electrocatalysis and thermal catalysis. However, the stability of surface structures and compositions still needs to be improved to obtain better long-term catalytic stability. It is noted that thermal annealing can adjust the surface structures and compositions to improve the stability. Transmission electron microscopy (TEM) plays a vital role in characterizing the morphology, structure, and composition of nanoparticles. Specifically, the utilization of in situ TEM can allow for observing …

Floating Treatment Wetlands For Brackish Waters: Plant Selection And Nutrient Uptake Potential., Andrea Landaverde

All Theses

Brackish water bodies in coastal regions provide critical ecosystem services that support human and environmental health. Anthropogenic activities such as agricultural and industrial activities, construction, urban settlements, and tourism contribute to increased inputs of nitrogen (N) and phosphorus (P) in brackish coastal ecosystems. Excess nutrients can lead to impaired water quality and affect marine organisms. Floating treatment wetlands (FTWs) are a vegetated-base technology used to remove contaminants from water column, that has been mainly studied and applied in freshwater systems. Application of FTWs in brackish systems requires further investigation, as high salinity in brackish waters could result in toxicity to …

Quantifying Shear Stresses In Tissue Engineered Aortic Heart Valves, Raj Nitin Dave

All Theses

Present heart valve prosthesis have limitations such as capability to grow, repair and remodel post implantation. Tissue engineering offers to be a promising alternative to overcome these limitations. Maturation of seeded human cells on the valve subjected to favorable growth conditions in the bioreactor is critical to the success of tissue engineered heart valves. Mechanical stress and strain which results from the pressure and flow conditions in the bioreactor plays a critical role on the developing valve tissue and are currently unknown. The goal of this research is to relate the magnitude of wall shear stress (WSS) within the heart …

Battery Energy Storage System Mitigation Strategies For The Grid Impacts Of Electric Vehicle Charging Infrastructure, Chance Stowe

All Theses

The face of transportation is changing as a greater number of companies and private individuals switch from traditional automobiles to electric vehicles. This surge has been bolstered by improvements in technology, increased marketing, and a heightened focus on the role humanity plays in climate change. This advancement brings a growth in electrical demand caused by the charging loads of these vehicles. Due to the quick, sudden rise of this technology, the utility energy industry is still in the early stages of preparing for electric vehicle loads beyond the traditional load growth.

Though the technology for battery energy storage has been …

Mechanochromic Tunable Emissions Of Hydrogel Encapsulated Radioluminescent Crystalline Colloidal Arrays, Sarah Mell

All Theses

Crystalline colloidal arrays (CCAs) are periodic dielectric arrays composed of monodisperse, negatively charged nanoparticles with unique optical characteristics. Poly(styrene-co-propargyl acrylate) (PS-PA) based copolymer nanoparticles synthesized via an emulsion polymerization form the basis of the CCAs in this work. The negatively charged surfaces result in the colloidal nanoparticles self-assembling into a face-centered cubic (fcc) crystal-like structure. The long-range order and spatial periodicity of the array result in a rejection wavelength, characteristic of CCAs, in which a specific wavelength of light is forbidden from propagating throughout the optical system. The CCAs exhibit mechanochromism through a rejection wavelength shift corresponding to a change …

Fathom In Color: Expansion Of Reproduceable Color In Interference Pattern-Based Printed Motion And Depth Effects, Dovie Jeffcoat

All Theses

Value-added printed embellishments are increasingly sought after as brands compete for consumer attention. Fathom Optics’ method for printing motion and depth effects provides a cost-efficient, reduced waste embellishment option. One of Fathom’s current limitations is producing effects with vibrant color. The current standard practice for producing color Fathom Effects tends to darken and desaturate the final embellishment’s color. This study endeavors to determine how an ink color's components (hue, value and chroma) may determine a Fathom Effect’s contrast or intensity. To achieve this, fifteen color inks were selected to flexographically print the effect patterns. Samples were taken from each color …

Predictive Performance And Teaming Via The Mist-C Ocean Hierarchy Utilizing Personality And Skills, Brighton H. Owen

All Theses

This thesis seeks to establish and define the individual, the team as an entity, and qualify various metrics to predict team performance. When several individuals come together, they form a team that is often capable of designing and developing concepts beyond the individual on their own by methods of task dispersion, goal orientation, communication, and more. With these teams comes growth and increased performance leading to more efficient processes and better metrics by which performance may be measured. To achieve this, 34 engineering students in the AerosPACE senior design program, which lasted two semesters, were asked to complete surveys in …

Analysis Of The Self-Heating Effect On Unfilled Poly(Methyl Methacrylate) Due To Cyclic Behavior, Muhammed R. Kose

All Theses

Poly(methyl methacrylate, (PMMA) has been implemented as part of the supporting structure in complete hip and knee replacements since the 1950s. Known as bone cement while in the body, PMMA is known to undergo compressive and tensile stresses that wear down the bio-compatible barrier and cause pieces to come loose inside the human body. These pieces are then attacked by the body’s own nervous system, leading to inflammation, and eventually necessitating replacement. It has been documented that under cyclic loading PMMA can reach temperatures that start to degrade its tensile capabilities. In this study the potential cause of self-heating was …

Soft Web-Based Continuum Robot Grippers, Anthony Carambia

All Theses

We discuss the potential of soft webs to enhance robotic grasping. Specifically, we explore a novel combination of compliant continuum digits interspersed with a flexible material. The resulting webbed structure offers the potential for new modes of robust and adaptive object grasping. We introduce and describe two webbed grippers featuring alternate modes of actuation: pneumatic muscles and remotely actuated tendons. Experiments with the grippers demonstrate their ability to gently capture small, fragile, and non-cooperative objects.

Assessment Of Parameters For A Safe And Equitable Roadway Network For Pedestrians Of South Carolina, Sababa Islam

All Dissertations

In 2019, South Carolina ranked fourth in the nation in pedestrian fatalities per 100,000 population. There has been a 68% increase in total pedestrian crashes in SC from 2011 to 2018. Walking might be a choice for some individuals; however, it is mandatory for some users due to the unavailability of personal automobiles or physical disability. Thus, pedestrian crashes and resulting deaths and injuries can disproportionately affect these population segments. Nationwide pedestrian crash statistics reveal American Indian or Alaskan Native and African American populations are overburdened with pedestrian crashes. This research aims to help mitigate this overburden of pedestrian crashes …

Wetland Uranium Transport Via Iron-Organic Matter Flocs And Hyporheic Exchange, Connor J. Parker

All Dissertations

Uranium (U) released from the M-Area at the Department of Energy Savannah River Site into Tims Branch, a seasonal wetland and braided stream system, is estimated to be 43,500 kg between 1965 and 1984. The motivation for this work is the uranium’s persistence in the wetland for decades, where it is estimated that 80% of the U currently remains in the Tims Branch wetland. U has begun to incorporate into wetland iron (Fe) and carbon cycles, associating with local Fe mineralogy and deposits of rich wetland organic matter (OM). The objective of this work is to characterize the chemical phases …

Investigating The Effects Of Topology On The Fracture And Failure Mechanisms Of Low Density Metamaterials, Kaitlynn Melissa Conway

All Dissertations

Advances in additive manufacturing have enabled the creation of low density metamaterials with fine features and complex topographies. These new metamaterial topologies and size scales not previously possible broaden the spectrum of lightweight materials with unique properties that are advantageous in a variety of applications. There however is a lack of understanding of metamaterial failure and fracture behaviors. Studies tend to report only a few material properties rather than a comprehensive description of behavior. Due to this, there is a hesitancy to incorporate metamaterials into engineering designs despite proven remarkable properties. This work seeks to investigate in three parts the …

Performance Of Geotechnical Systems Under Extreme Hydroclimatic Events Using Finite Element Modeling, Tharshikka Vickneswaran

All Dissertations

Failure of geotechnical systems during hydroclimatic events such as heavy rainfall, flood, and drought often leads to significant socio-economic loss. The time-dependent stability and deformation behaviors of geotechnical systems subjected to hydroclimatic events must be investigated using a coupled flow-deformation formulation because the strength and deformation parameters vary with the degree of saturation and/or matric suction of the soil. Although the impacts of the hydroclimatic events on the geotechnical systems are assessed and summarized in the previous studies, all the analyses were carried out in a loosely coupled manner and/or uncoupled manner without considering the effects of water flow in …

Computational Study Of Dense Gas Dispersion In Urban Areas, Rasna Sharmin

All Dissertations

A series of steady-state simulations have been conducted to investigate removal of dense gas from a simple square canyon formed between two square cross-section obstacles. Due to urbanization and industrialization, there always lies a high risk of exposure to harmful pollutants which can result from accidental release of toxic gasses. Those are often denser than the atmosphere. and can easily get trapped in between buildings in urban canopies. It is important to have full understanding of flushing mechanism of dense fluid inside urban canopies by steady turbulent flow because the exposure to these toxic dense gasses can be catastrophic. There …

Characterization Of Water Flow And Solute Transport Driven By Preferential Flow In Soil Vadose Zone, Abdullah Al Mamun

All Dissertations

The vadose zone acts as a buffer zone between the ground surface and the aquifers underneath and controls the transmission of infiltrating water and contaminants, for example, pesticides and chemical spills. Therefore, understanding the flow and transport processes that dominate the vadose zone is important. Macropores are ubiquitous and particularly found in abundance in the vadose zone. These macropores facilitate preferential flow, through which water travels rapidly deep into the soil, bypassing most of the porous matrix. Preferential flow and transport have environmental significance as their processes impact hydrology, ecology, agriculture, subsurface contamination, and waste management sectors. Thus, the overall …

Environmental Exploration With Long, Thin Tendril Robots, Or Building Plant Based Robots And Teaching Them How To Feel, Michael Benjamin Wooten

All Dissertations

Continuum robots offer unique potential benefits for environmental exploration, notably in using their maneuverability to navigate congested environments. In this dissertation, we show how circumnutation, a motion strategy, commonly employed by plants, can be implemented, and usefully exploited, with continuum robots. We discuss how the kinematics of circumnutation, which combines local backbone growth with periodic backbone bending, can be created using extensible continuum robot hardware. The underlying kinematics are generated by adapting kinematic models of plant growth. We illustrate the effectiveness of that approach with experimental results with a tendril robot exploring a congested environment. However, significant challenges remain in …

Digitalization Of Construction Project Requirements Using Natural Language Processing (Nlp) Techniques, Fahad Ul Hassan

All Dissertations

Contract documents are a critical legal component of a construction project that specify all wishes and expectations of the owner toward the design, construction, and handover of a project. A single contract package, especially of a design-build (DB) project, comprises hundreds of documents including thousands of requirements. Precise comprehension and management of the requirements are critical to ensure that all important explicit and implicit requirements of the project scope are captured, managed, and completed. Since requirements are mainly written in a natural human language, the current manual methods impose a significant burden on practitioners to process and restructure them into …

Effects Of Continuous In Situ Low-Dose Ionizing Radiation On Microorganisms, Molly E. Wintenberg

All Dissertations

Precise detection and monitoring of nuclear fuel cycle, enrichment, and weapon development activities are critical for supporting warfighter preparation in chemical, biological, radiological, nuclear, and explosives (CBRNE) operations, clandestine activities, and nuclear compliance. A biological sensing system could serve as an alternative to traditional detection methods by using organic material naturally present in the environment to discreetly detect residual trace nuclear material. Microorganisms provide an optimal platform for an alternative sensing system; however, their response to low levels of ionizing radiation is poorly characterized. Combining the power of next-generation sequencing and transcriptomic analysis, this dissertation takes an approach to obtain …

Examining The Impact Of Design Features Of Electronic Health Records Patient Portals On The Usability And Information Communication For Shared Decision Making, Rong Yin

All Dissertations

The use of the Electronic Health Records (EHR) patient portal has been shown to be effective in generating positive outcomes in patients’ healthcare, improving patient engagement and patient-provider communication. Government legislation also required proof of its meaningful use among patients by healthcare providers. Typical patient portals also include features such as health information and patient education materials. However, little research has examined the specific use of patient portals related to individuals with specific diseases such as inflammatory bowel diseases (IBDs). IBDs are life-long, not curable, chronic diseases that can impact the whole population. Individuals with IBDs may have higher needs …

Pulse-Coupled Oscillator Networks: Achieving Phase Continuity And Learning Optimal Control In Physical Systems, Timothy Anglea

All Dissertations

In this dissertation, we consider the application of pulse-coupled oscillator theory to real-world, physical networks. When the phase of an oscillator is associated with a physical measure, such as clock timing or robotic heading, discontinuous adjustments of the oscillator's phase is undesirable and potentially disadvantageous. Rather, continuous adjustment of the oscillator phase value is needed over a certain amount of time. To ensure that both synchronization and desynchronization can still be achieved under the constraint of continuous phase value changes, we pursue a novel approach to analyze the generalization of a pulse-coupled oscillator network with a time-varying coupling strength. We …

Synthesis And Molecular Processes Governing Self-Healing Polymeric Materials, Siyang Wang

All Dissertations

Self-healing polymers capable of recovering from physical damages are promising materials for advanced technologies. In these studies, we developed routes to achieve self-healable properties in acrylic-based copolymers that rely on non-covalent dipolar interactions present in essentially all polymeric materials. Using a combination of spectroscopic tools, thermo-mechanical analysis, and molecular dynamic (MD) simulations, these studies have shown that dipolar interactions lead to conformational changes of macromolecular segments which, in turn, result in self-healing without external intervention. This dissertation also describes the development of novel self-healable acrylic-based covalent adaptable networks (CANs) that combine reprocessing and self-healing properties. The utilization of dipolar interactions …

Missing Samples Reconstruction Using An Efficient And Robust Instantaneous Frequency Estimation Algorithm, Sadiq Ali, Nabeel Ali Khan

Turkish Journal of Electrical Engineering and Computer Sciences

In order to recover missing samples in a nonstationary signal, this paper employs a time-signal analysis and filtering method. The instantaneous frequency of a multicomponent signal is first estimated by employing a robust and computationally efficient method. Then the time-frequency filtering is performed using a dechirping operation to recover missing samples. These steps are repeated until convergence. The proposed method achieves better performance than the state of art methods both in terms of the accuracy of the recovered signal and computational efficiency.

Stochastic Day-Ahead Optimal Scheduling Of Multimicrogrids: An Alternating Direction Method Of Multipliers (Admm) Approach, Amin Safari, Hossein Nasiraghdam

Turkish Journal of Electrical Engineering and Computer Sciences

Multimicrogrid system is a novel notion in modern power systems as a result of developing renewable-based generation units and accordingly microgrids in distribution networks. Their energy management might be challenging due to presence of independent units. Thus, in this paper, a decentralized method for energy management of multimicrogrid systems has been proposed. Decentralized methods can enhance the privacy of users and reduce the burden of calculations. Alternating direction method of multipliers (ADMM) is selected as a decentralized approach which has the capability of breaking problems with complicating constraints in order to facilitate the solving process. Using decentralized approach not only …

Priority Enabled Content Based Forwarding In Fog Computing Via Sdn, Yasi̇n İnağ, Metehan Güzel, Feyza Yildirim Okay, Mehmet Demi̇rci̇, Suat Özdemi̇r

Turkish Journal of Electrical Engineering and Computer Sciences

As the number of Internet of Things (IoT) applications increases, an efficient transmitting of the data generated by these applications to a centralized cloud server can be a challenging issue. This paper aims to facilitate transmission by utilizing fog computing (FC) and software defined networking (SDN) technologies. To this end, it proposes two novel content based forwarding (CBF) models for IoT networks. The first model takes advantage of FC to reduce transmission and computational delay. Based on the first model, the second model makes use of the prioritization concept to address the timely delivery of critical data while ensuring the …

Estimation Of Mode Shape In Power Systems Under Ambient Conditions Using Advanced Signal Processing Approach, Rahul S, Sunitha R

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a dynamic approach for the monitoring and estimation of electromechanical oscillatory modes in the power system in real time with less computational burden. Extensive implementation of phasor measurement units (PMU) and the utilization of advanced signal processing techniques help in identifying the dynamic behaviors of oscillatory modes. Conventional nonstationary analysis techniques are computationally weak to handle a larger quantity of data in real-time. This research utilizes the variational mode decomposition (VMD) for signal decomposition, which is highly tolerant to noise and computationally more robust. The predefined parameters of the VMD process are assigned using FFT analysis of …

Residential Energy Management System Based On Integration Of Fuzzy Logic And Simulated Annealing, Ömer Ci̇han Kivanç, Beki̇r Tevfi̇k Akgün, Semi̇h Bi̇lgen, Sali̇h Bariş Öztürk, Suat Baysan, Ramazan Nejat Tuncay

Turkish Journal of Electrical Engineering and Computer Sciences

With the increase in prosperity level and industrialization, energy need continues to overgrow in many countries. To meet the rapidly increasing energy needs, countries attach great importance to using limited natural resources rationally, diversifying their energy production using novel technologies, improving the efficiency of existing technologies, and implementing policies and strategies toward alternative energy sources. In particular, individual energy prosumers (someone that both produces and consumes energy) head toward smart home energy management systems (SHEMS) that include renewable energy sources in their homes. By integrating PV solar panels into houses, there is a need to optimize home energy production/consumption scenarios …

Analog & Digital Metronome, Andrew Deering, Paul Kim, Gabriel Ogden

Mechatronics Final Projects

The metronome is a tabletop device designed to keep a consistent rhythm for musicians to follow. This specific metronome combines the visuals of a traditional analog metronome with the ease of use and functionality of its digital counterpart. Like a conventional digital metronome, the user can control the beats per minute (BPM) using the control knob on the front of the device and read the current BPM value on the front mounted display. The user can observe

Machine Learning Based Surrogate Model For Hurricane Storm Surge Forecasting In The Laguna Madre, Cesar E. Davila Hernandez

Theses and Dissertations

Texas coastal communities are at constant risk of hurricane impacts every storm season. It is especially important to model and predict storm surge variations during hurricane and storm events. Traditionally, hurricane storm surge predictions have been the result of numerical hydrodynamics based simulations. This type of simulations often requires high amounts of computational resources and complex ocean modelling efforts. Recently, machine learning techniques are being explored and are gaining popularity in hydrologic and ocean engineering modelling fields based on their performance to model nonlinear relationships and low computational requirements for prediction. Advances in machine learning and artificial intelligence (A.I.) demand …

Behavior Of Narrow Mechanically Stabilized Earth Walls With Secondary Reinforcement, Abraham Alejandro Alvarez Reyna

Theses and Dissertations

Mechanically Stabilized Earth (MSE) walls have been used in past decades as an alternative, cost-effective, and performance solution to replace conventional retaining walls. AASHTO guidelines recommend a reinforcement length-to-height ratio of 0.7. However, this ratio is not applicable where there exist constraint conditions. FHWA guidelines recommend the minimum reinforcement length-to-height ratio of 0.3 for Narrow Mechanically Stabilized Earth (NMSE) walls in these cases. However, published guidelines have not sufficiently accounted for several parameters influencing NMSE performance and efficiency. Using finite element analysis (PLAXIS 2D), this study focuses on finding a relation between the length-to-height ratio and other parameters/components of the …

Monitoring Of Tool Wear And Surface Roughness Using Anfis Method During Cnc Turning Of Cfrp Composite, Md Mofakkirul Islam

Theses and Dissertations

Carbon fiber-reinforced plastic (CFRP) is gaining wide acceptance in areas including sports, aerospace and automobile industry . Because of its superior mechanical qualities and lower weight than metals, it needs effective and efficient machining methods. In this study, the relationship between the cutting parameters (Speed, Feed, Depth of Cut) and response parameters (Vibration, Surface Finish, Cutting Force and Tool Wear) are investigated for CFRP composite. For machining of CFRP, CNC turning operation with coated carbide tool is used. An ANFIS model with two MISO system has been developed to predict the tool wear and surface finish. Speed, feed, depth of …