Engineering Commons^™

The Development Of Tigra: A Zero Latency Interface For Accelerator Communication In Risc-V Processors, Wesley Brad Green

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Field programmable gate arrays (FPGA) give developers the ability to design application specific hardware by means of software, providing a method of accelerating algorithms with higher power efficiency when compared to CPU or GPU accelerated applications. FPGA accelerated applications tend to follow either a loosely coupled or tightly coupled design. Loosely coupled designs often use OpenCL to utilize the FPGA as an accelerator much like a GPU, which provides a simplifed design flow with the trade-off of increased overhead and latency due to bus communication. Tightly coupled designs modify an existing CPU to introduce instruction set extensions to provide a …

Synthesis Of Monodisperse Nanoscintillators At High Temperatures For Biomedical Relevant Applications, Eric Zhang

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Luminescent sub-100 nm particulates continuously generate immense research interest in the biomedical field for imaging, theranostics, and optogenetics. Conventionally, upconversion nanoparticles or UV activated semiconductors are studied, however these materials are limited by biological barriers such as the skin which reduces the penetration depth of these excitation sources, tissue's auto- fluorescence, and toxicity. One approach to overcome these challenges is to use nanoscintillators (sub-100 nm materials that can generate visible light using high energy excitation sources such as x-rays) which can generate light locally to the human body. Numerous scintillators have been reported since the discovery of x-rays from the …

The Control Strategies Of Brominated Organic Disinfection By-Products: Adsorption With Pre-Chlorination And Photodegradation, Cagri Utku Erdem

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Increasing water pollution, scarcity, and seasonal events force water treatment plants to improve existing treatment techniques and/or implement new methods to enhance drinking water treatment and comply with disinfection by-product (DBP) regulations. A limited number of studies examine the pre-chlorination prior to activated carbon (AC) adsorption for the removal of DBP precursors, and there are no comprehensive and representative treatment conditions in current literature. Although many studies investigated photodegradation of individual DBPs by low pressure ultraviolet (UV₂₅₄) light, there is still lack of information and limited understanding of photodegradation of total organic halogens and practical implications of UV …

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

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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

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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 …

Investigating The Effects Of Sic Abrasive Particles On Friction Element Welding, Gaurav Awate

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The growing demands on reducing the harmful emissions from automobiles have forced automakers to reduce the weight of the vehicle. The increasing demands on improving the fuel economy also has challenged automotive manufacturers to make the vehicle as lightweight as possible. However, the challenge is also to ensure that the vehicle meets safety standards. For the vehicle to meet these standards, it needs to be of adequate strength as well. Automotive manufacturers have adopted a strategy of using multi-material construction to achieve the target. But with multi-material construction comes the requirement of advanced joining techniques that are capable of joining …

The Role Of Consumers In The Adoption Of Alternatively Fueled Vehicles And Mitigation Of Vulnerabilities Associated With Electric Vehicle Charging, Elaina D. Stuckey

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Electric vehicles have the potential to replace traditional automobiles as the primary form of transportation. Despite major improvements in technology and an expanding focus on climate change making electric vehicles more practical than ever before, consumers are still wary of adopting them for legitimate reasons such as costs and charging infrastructure. Therefore, a concerted effort must be made to persuade individuals and companies to adopt this beneficial technology to reduce the carbon footprint and catalyze the construction of important charging infrastructure.

Though there are a multitude of benefits to adopting electric vehicles, there will be some negative effects on the …

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

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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

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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 …

Fabrication Of Hydrogel Microparticles For Acute Treatment Of Penetrating Brain Injuries, Isabell Foulger

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Traumatic brain injuries (TBIs) are a type of acquired head trauma that results from an external force to the head. The development and severity of the secondary injury increases the risk of neurodegeneration and reduced cognitive recovery. Glucocorticoids are potent antiinflammatory therapeutics that have been investigated for potential treatment of TBIs, strokes, and other neuroinflammatory pathologies. However, their clinical application has been limited due to their ability to induce a variety of side effects, including adrenal suppression, edema, and reduced plasticity of the hippocampus. The use of a localized drug delivery system would overcome these systemic concerns. In previous studies, …

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

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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 …

Design Of A Four Channel Pulsatile Perfusion Bioreactor For Ex-Vivo Study Of Vascular Grafts, Thomas M. Fair

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Cardiovascular diseases are the leading cause of death in the United States. Atherosclerosis in peripheral arteries is a major contributing factor. Autologous saphenous vein grafts are the most common bypass grafts for treating peripheral artery diseases. A quarter of these grafts fail within a year, and around half have failed within 10 years of the initial surgery. Graft failure is attributed to the development of intimal hyperplasia indicated by the migration and proliferation of vascular smooth muscle cells, fibroblasts, and the deposition of extracellular proteins.

Increases in flow, pressure, the pulse frequency, and the differential of pressure that model an …

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

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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 …

An Experimental Analysis Of Thin Sheet Metal Bending By Ultrafast Laser Peen Forming, Bryce J. Tessmann

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This study demonstrates the viability of femtosecond laser peen forming for bidirectional sheet metal bending. Ultrafast laser forming is a valuable method thanks to its flexibility, negation of springback, no need for a confining or protective layer, and minimalization of thermal degradation in comparison to other forming processes. However, femtosecond lasers have traditionally been believed to be unsuitable for laser forming in comparison to nanosecond lasers, particularly bidirectional bending, because the induced shock waves were expected to be weak. Conversely, in this study it is elucidated that the femtosecond laser-induced shock waves are extremely strong (several hundred GPa) but the …

Portable U-Bent Optical Fiber Biosensor For Detecting Microcystin-Lr, Quan Dio Anh Le

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Cyanobacteria are the only known prokaryotes that can photosynthesize. Due to their unique ability, they are important entities in the global carbon and nitrogen cycles. However, two factors can turn cyanobacteria into a nuisance. In general, eutrophication is the process that supplies external nutrients that are needed for cyanobacteria blooms into bodies of water from the surrounding environment. Climate warming intensifies this process by producing carbon dioxide, methane, and nitrous oxide. With cyanobacteria blooms occurring worldwide, they are becoming a bigger threat to human health, and there has been increased interest in detecting cyanobacteria and their toxic byproducts.

For instance, …

A Quantitative Comparison Of Algorithmic And Machine Learning Network Flow Throughput Prediction, Cayden Wagner

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Applications ranging from video meetings, live streaming, video games, autonomous vehicle operations, and algorithmic trading heavily rely on low latency communication to operate optimally. A solution to fully support this growing demand for low latency is called dual-queue active queue management (AQM). Dual-queue AQM's functionality is reduced without network traffic throughput prediction.

Perhaps due to the current popularity of machine learning, there is a trend to adopt machine learning models over traditional algorithmic throughput prediction approaches without empirical support. This study tested the effectiveness of machine learning as compared to time series forecasting algorithms in predicting per-flow network traffic throughput …

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

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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

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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

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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

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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 …

Discrete Element Modeling Of The Shape- And History-Dependent Behavior Of Granular Materials, Feiyang Chen

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Granular materials, such as biomass feedstocks, agricultural grains, pharmaceutical pills, and geomaterials, are widespread in nature, industrial systems, and everyday life. Fundamentally, the bulk mechanical behavior of granular materials is governed by particle-level attributes such as particle morphology, surface roughness, and contact behavior. Among various numerical methods developed for modeling granular materials, the particle-based discrete element method (DEM) is particularly suited and effective in modeling the mechanical, flow, and failure behavior of granular materials.

Focusing on one specific type of granular material (i.e., biomass feedstocks), the main objective of this dissertation is to develop and validate novel DEM models that …

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

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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

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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

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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 …

A Study Of Scheduling Problems With Sequence Dependent Restrictions And Preferences, Nitin Srinath

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In some applications like fabric dying, semiconductor wafer processing, and flexible manufacturing, the machines being used to process jobs must be set up and serviced frequently. These setup processes and associated setup times between jobs often depend on the jobs and the sequence in which jobs are placed onto machines. That is, the scheduling of jobs on machines must account for the sequence-dependent setup times as well. These setup times can be a major factor in operational costs. In fabric dyeing processes, the sequence in which jobs are processed is also important for quality, i.e., there is a strong preference …

Characterization Of Friction Element Welding Using Finite Element Modeling, Ankit Varma

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Friction element welding (FEW) has been advocated as a solution to weld different materials together, with the ability to join high-strength materials for a range of thicknesses with low input energy and a short processing time. This work develops a coupled thermal-mechanical finite element model to better understand the physical mechanisms involved in the process and to predict temperature and material flow during the process. Furthermore, microstructural analysis is performed for the steel layer using a scanning electron microscope and Vickers microhardness tester to understand the variation in its grain structure and hardness. Results from the finite element model and …

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

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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

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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 …

Double Tolerance Design In Stochastic Production Environments, Di Liu

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In a production process, it is impossible to produce parts with exact specifications. Thus, specific ranges, i.e., tolerances, are commonly employed to define intervals for the quality characteristics of conforming products (Wu & Tang (1998)). Usually, a product is deemed conforming when the measurement of the quality characteristic falls within the tolerance. If the measurement falls outside the tolerance, the product is nonconforming and it can be reworked or scrapped. One of the important engineering problems commonly faced by practitioners is to determine optimal engineering tolerances to be used in production. As a result, tolerance design techniques are widely used …

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

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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 …