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Title: BIOLUMINESCENCE OF THE CTENOPHORE MNEMIOPSIS LEIDYI: FIRST FLASH KINETICS.
Creator: Blackburn, Abigail, Twardowski, Michael, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: The ctenophore Mnemiopsis leidyi is an opportunistic species that can be extremely abundant and invasive in many parts of the world. It is well known for its bright bioluminescence, but its light emission response to flow stimulation has not been rigorously quantified. The objective of this study is to determine the luminescent response of M. leidyi to several types of mechanical stimuli, an impeller pump with the Underwater Bioluminescence Assessment Tool (UBAT) bathyphotometer and stirring...
Show moreThe ctenophore Mnemiopsis leidyi is an opportunistic species that can be extremely abundant and invasive in many parts of the world. It is well known for its bright bioluminescence, but its light emission response to flow stimulation has not been rigorously quantified. The objective of this study is to determine the luminescent response of M. leidyi to several types of mechanical stimuli, an impeller pump with the Underwater Bioluminescence Assessment Tool (UBAT) bathyphotometer and stirring as the stimulus within an integrating sphere. Tests were conducted with three day old cydippid larvae, analyzing flash parameters of rise time, peak intensity, decay slope, decay time, total integrated emission, total mechanically stimulable luminescence (TMSL), integrated flash emission, and flash duration. There were four patterns of bioluminescent responses measured with the UBAT, but they did not have statistically different flash kinetics. For the integrating sphere, the average peak intensity and TMSL were much greater than for the UBAT due to the different forms of stimulation. This study provides a well-defined baseline of cydippid larvae flash responses which may be used for identifying this species at this life stage in situ.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014341
Subject Headings: Mnemiopsis leidyi, Bioluminescence, Ctenophores
Format: Document (PDF)

Title: NOVEL KIRIGAMI-INSPIRED FLEXIBLE ROBOTIC EXTENSION FOR MOBILE PLATFORMS.
Creator: Den Ouden, Casey, Su, Tsung-Chow, Ouyang, Bing, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Since 2010, aquaculture practices have produced 70% of global seafood consumption. However, this fast-growing sector of agriculture has yet to see the adoption of advanced technologies to improve farm operations. The Hybrid Aerial Underwater robotiCs System (HAUCS) is an Internet of Things (IoT) framework that aims to bring transformative changes to pond aquaculture. This project focuses on the latest developments in the HAUCS mobile sensing platform and field deployment. A novel rigid...
Show moreSince 2010, aquaculture practices have produced 70% of global seafood consumption. However, this fast-growing sector of agriculture has yet to see the adoption of advanced technologies to improve farm operations. The Hybrid Aerial Underwater robotiCs System (HAUCS) is an Internet of Things (IoT) framework that aims to bring transformative changes to pond aquaculture. This project focuses on the latest developments in the HAUCS mobile sensing platform and field deployment. A novel rigid Kirigami-based robotic extension subsystem was created to expand the functionality of the HAUCS platform. The primary objective of this design was to limit the surface area of an extender arm on the drone during flight operations and minimize the in-flight drag. By utilizing a novel combination of shape memory polymer (SMP) and nitinol to extend and retrieve the sensing arm, the structure was able to conserve energy while operating under varying environmental conditions.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014324
Subject Headings: Aquaculture, Sensors, Robotics
Format: Document (PDF)

Title: MICROFLUIDIC ELECTRICAL IMPEDANCE TECHNOLOGY FOR POINT-OFCARE ASSESSMENT OF SICKLE CELL DISEASE.
Creator: Dieujuste, Darryl, Du, Sarah, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Sickle Cell Disease (SCD) is a genetic disease that affects approximately 100,000 people in the USA and millions worldwide. The disease is defined by a mutation in hemoglobin, the red blood cell’s oxygen carrying component. Under hypoxic (low oxygen) conditions, the mutated hemoglobin (known as HbS) polymerizes into rigid fibers that stretch the cell into a sickle shape. These rigid cells can occlude blood vessels and cause an individual immense pain. Currently, no point-of-care devices exist...
Show moreSickle Cell Disease (SCD) is a genetic disease that affects approximately 100,000 people in the USA and millions worldwide. The disease is defined by a mutation in hemoglobin, the red blood cell’s oxygen carrying component. Under hypoxic (low oxygen) conditions, the mutated hemoglobin (known as HbS) polymerizes into rigid fibers that stretch the cell into a sickle shape. These rigid cells can occlude blood vessels and cause an individual immense pain. Currently, no point-of-care devices exist in the market for assisting those with SCD. Using microfluidics with custom designed portable impedance measuring hardware we can achieve label-free in vitro analyses of SCD rheology. This dissertation presents two impedance-based devices for finger-prick volume blood testing, including a microflow cytometer for SCD diagnostics and a vaso-occlusion tester for monitoring blood flow activities. First, the microflow cytometer is validated by measuring the electrical impedance of individual cells flowing through a narrow microfluidic channel. Cellular impedance is interpreted by changes in subcellular components due to oxygen association-dissociation of hemoglobin, using an equivalent circuit model and Multiphysics simulation. Impedance values of sickle cells exhibit remarkable deviations from normal blood cells. Such deviation is quantified by a conformity score, which allows for measurement of SCD heterogeneity, and potentially disease severity. Findings from this study demonstrate the potential for SCD screening via electrical impedance. Second, a vaso-occlusion tester is validated by measuring the impedance response of blood flow within a microfluidic mimic of capillary bed.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014243
Subject Headings: Sickle cell anemia, Microfluidics, Point-of-care testing, Electric Impedance
Format: Document (PDF)

Title: UNDERSTANDING BUBBLE GROWTH BEHAVIOR DURING NUCLEATE BOILING.
Creator: Ghazvini, Mahyar, Kim, Myeongsub, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Boiling heat transfer associated with bubble growth is perhaps one of the most efficient cooling methodologies due to its sizeable latent heat during phase change. Despite significant advancement, numerous questions remain regarding the fundamentals of bubble growth mechanisms, a primary source of enhanced heat dissipation. This thesis provides a comprehensive examination of the mechanisms involved in the growth of bubbles during nucleate boiling. By conducting a combination of experiments...
Show moreBoiling heat transfer associated with bubble growth is perhaps one of the most efficient cooling methodologies due to its sizeable latent heat during phase change. Despite significant advancement, numerous questions remain regarding the fundamentals of bubble growth mechanisms, a primary source of enhanced heat dissipation. This thesis provides a comprehensive examination of the mechanisms involved in the growth of bubbles during nucleate boiling. By conducting a combination of experiments and numerical analyses, the goal is to enhance our understanding of bubble growth phenomena and their impact on heat transfer. Initially, the experimental work focuses on comparing the heat transfer performance and parameters related to bubble dynamics between regular and modified fin structures. The findings demonstrate that the modified fin structure, which featured artificial nucleation sites, exhibits superior heat transfer characteristics. This improvement is attributed to changes in the bubble departure diameter, bubble departure frequency, and growth time. Subsequently, an artificial neural network is developed to accurately predict the bubble departure diameter based on the wall superheat and subcooling level. This predictive model provides valuable insights into bubble behavior originating from artificial nucleation sites.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014295
Subject Headings: Nucleate boiling, Ebullition, Heat--Transmission
Format: Document (PDF)

Title: Some topics related to the vibrations of deterministic and non-deterministic metamaterial structures.
Creator: Li, Yuchen, Elishakoff, Isaac, Challamel, Noël, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: In this thesis, we will explore different kinds of metamaterial or architectural structural problems, including structures composed of heterogeneous media with bi periodic sub-structures, discrete structures with sub-elements or continuous structures with discrete attached sub-elements. The thesis is composed of seven parts. After having introduced the specificities of metamaterial mechanics, the second chapter is devoted to the vibration of discrete beam problems called Hencky bar-chain...
Show moreIn this thesis, we will explore different kinds of metamaterial or architectural structural problems, including structures composed of heterogeneous media with bi periodic sub-structures, discrete structures with sub-elements or continuous structures with discrete attached sub-elements. The thesis is composed of seven parts. After having introduced the specificities of metamaterial mechanics, the second chapter is devoted to the vibration of discrete beam problems called Hencky bar-chain model in a stochastic framework. It is shown that the lattice beam behaves as a nonlocal continuous beam problem, both in the deterministic and the non-deterministic analyses. The third chapter considers the vibration of continuous beams with the introduction of shear effects and attached periodically oscillators. A discussion on beam modelling, for example Timoshenko beam models or truncated Timoshenko beam models is included. It is shown that the bandgap phenomenon observed for metamaterial beams can be accurately captured by a truncated Timoshenko beam model which means the last term in the Timoshenko equation is not that important.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014289
Subject Headings: Metamaterials, Hencky bar-chain model, Lattice theory, Engineering
Format: Document (PDF)

Title: INVESTIGATING THE ROLE OF BIOMOLECULE/MINERAL INTERACTIONS VIA CALCITE AND CELESTITE MODEL SYSTEMS.
Creator: Martin, Andrienne, Merk, Vivian, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: In this research, we use calcite and celestite inorganic model systems to better understand biological crystallization in the presence of organic biomolecules. Our goal is to understand what happens when biomolecules occlude into crystals and how that affects the structural organization. Specifically, we focus on the role the respective biomolecule chemistry plays in regulating the incorporation into a crystal. To visualize and characterize the biomolecule/mineral role in crystallization, a...
Show moreIn this research, we use calcite and celestite inorganic model systems to better understand biological crystallization in the presence of organic biomolecules. Our goal is to understand what happens when biomolecules occlude into crystals and how that affects the structural organization. Specifically, we focus on the role the respective biomolecule chemistry plays in regulating the incorporation into a crystal. To visualize and characterize the biomolecule/mineral role in crystallization, a variety of techniques were used to image and analyze the respective model systems. The synthesized single crystals were characterized by light microscopy (LM). Scanning electron microscopy (SEM) and field-emission SEM (FE-SEM) were used to examine the morphology of the crystals. Structural and topographical analyses were carried out using atomic force microscopy (AFM). Fourier transform infrared spectroscopy (FTIR) and confocal Raman microscopy were both used to characterize functional groups, where Raman spectroscopic mappings provided the region-specific chemical composition of the crystal.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014287
Subject Headings: Crystallization, Biomolecules, Calcite, Celestite
Format: Document (PDF)

Title: DESIGN AND FAILURE ANALYSIS OF MULTI-COMPONENT MOORING LINES WITH NON-LINEAR POLYMER SPRINGS FOR FLOATING OFFSHORE WIND TURBINES.
Creator: McFadden, Jared, Mahfuz, Hassan, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: This research studied the effects of mooring line pretension, spring safe working load, and spring response curve on peak loads and platform surge. The maximum tension load from the optimized assembly was applied to a modelled section of 8-strand multiplait rope to study stress concentrations. The analyses yielded a mooring line pretensioned at 1250 kN with a 4500 kN safe working load degressive spring was optimal. Fatigue damage from 12-hour duration of 50-year storm conditions was 8.04 × 10...
Show moreThis research studied the effects of mooring line pretension, spring safe working load, and spring response curve on peak loads and platform surge. The maximum tension load from the optimized assembly was applied to a modelled section of 8-strand multiplait rope to study stress concentrations. The analyses yielded a mooring line pretensioned at 1250 kN with a 4500 kN safe working load degressive spring was optimal. Fatigue damage from 12-hour duration of 50-year storm conditions was 8.04 × 10−6. Infinite life is predicted at annual average conditions. The peak tension from 50-year storm conditions of 3671 kN and annual average conditions of 1388 kN was applied to the section model, yielding a maximum stress of 3.70 × 108 Pa and 2.01 × 108 Pa, respectively, from friction and longitudinal compression of the rope’s cross section. The maximum stress from the static structural analysis was 33.5% of polyester’s ultimate strength, based on the maximum stress failure criterion.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014245
Subject Headings: Wind turbines--Design and construction, Wind turbines--Testing, Deep-sea moorings
Format: Document (PDF)

Title: CORROSION MONITORING AND ANALYSIS OF REINFORCED CONCRETE: CORROSION RESISTANT ALLOYS AFTER LONG TERM EXPOSURE TO CHLORIDES.
Creator: Taylor, Redmayne, Presuel-Moreno, Francisco, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Reinforced concrete (RC) is the building block of modern architecture and industry. The failure of which is costly and dangerous. Typically made with carbon steel rebars, corrosion resistant alloys provide an alternative method of delaying failure. Stainless steels, while more expensive than carbon steels, provide excellent corrosion resistance, but less is known about the long term monitoring of corrosion activity for stainless steel than for carbon steel. This study looks at samples...
Show moreReinforced concrete (RC) is the building block of modern architecture and industry. The failure of which is costly and dangerous. Typically made with carbon steel rebars, corrosion resistant alloys provide an alternative method of delaying failure. Stainless steels, while more expensive than carbon steels, provide excellent corrosion resistance, but less is known about the long term monitoring of corrosion activity for stainless steel than for carbon steel. This study looks at samples prepared between 2005 and 2009 using 304SS, 316SS, and 2304SS rebars, as well as SMI and Stelax stainless steel clad carbon steel reinforcements embedded in three different concrete mixes. These selected samples are split into two exposure environments, inside humidity chambers within the laboratory and outdoor exposure. Measurements reported here were made monthly over the course of 250 plus days using the Galvanostatic Pulse method, Electrochemical Impedance Spectroscopy, and a Gecor 8 device. These methods were used to determine corrosion current, isolated corrosion current density, and solution resistance. Corrosion current density values calculated from measurements by the Galvanostatic Pulse and Electrochemical Impedance Spectroscopy method are too small to indicate corrosion, based on value ranges provided by Andrade. However, Gecor 8 corrosion current density values indicate low levels or moderate levels of corrosion for all samples compared to the Andrade’s value ranges. The area used by the Gecor is unknown, so it’s possible this is driving up the measured values.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014258
Subject Headings: Reinforced concrete, Corrosion resistant alloys, Carbon steel, Corrosion
Format: Document (PDF)

Title: A NEW DECELLULARIZED MATRIX FOR ENGINEERING AN ESOPHAGEAL CANCER MODEL IN A PERFUSION BIOREACTOR.
Creator: Brennan, Jordan Michael, Kang, Yunqing, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: The lack of physiologically relevant human esophageal cancer models has as a result that many esophageal cancer studies are encountering major bottleneck challenges in achieving breakthrough progress. To address the issue, here a 3D esophageal tumor tissue model was engineered using a biomimetic decellularized esophageal matrix in a customized bioreactor. To obtain a biomimetic esophageal matrix, a detergent-free, rapid decellularization method was developed to decellularize porcine esophagus...
Show moreThe lack of physiologically relevant human esophageal cancer models has as a result that many esophageal cancer studies are encountering major bottleneck challenges in achieving breakthrough progress. To address the issue, here a 3D esophageal tumor tissue model was engineered using a biomimetic decellularized esophageal matrix in a customized bioreactor. To obtain a biomimetic esophageal matrix, a detergent-free, rapid decellularization method was developed to decellularize porcine esophagus. The decellularized esophageal matrix (DEM) was characterized and the DEM was utilized for the growth of esophageal cancer cell KYSE30 in well plates and the bioreactor. Then the expression of cancerrelated markers of KYSE30 cells was analyzed and compared with formalin-fixed, paraffin-embedded (FFPE) esophageal squamous cell carcinoma (ESCC) tissue biospecimens. Results show that the detergent-free decellularization method preserved the esophageal matrix components and effectively removed cell nucleus. KYSE30 cancer cells proliferated well on and inside the DEM. KYSE30 cells cultured on the DEM in the dynamic bioreactor show different cancer marker expressions than those in the static well plate, and also share some similarities to the FFPE-ESCC biospecimens.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014206
Subject Headings: Cancer, Esophageal Neoplasms, Biomimetics
Format: Document (PDF)

Title: A Design Concept for Launch and Recovery of REMUS 100 AUV from WAM-V 16 USV.
Creator: Palmaccio, Brendan, Dhanak, Manhar, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: In this thesis, feasibility of a concept for launch and recovery of the Remus AUV from WAM-V USV is investigated. A modular recovery system which can be added to the WAM-V payload tray was designed, and based on a review of previous literature a CONOPS was developed for the launch and recovery process. The first phase of the CONOPS, which pertains to the position of the REMUS initially on the free surface prior to sling engagement is simulated using ANSYS AQWA. Preprocessing for the...
Show moreIn this thesis, feasibility of a concept for launch and recovery of the Remus AUV from WAM-V USV is investigated. A modular recovery system which can be added to the WAM-V payload tray was designed, and based on a review of previous literature a CONOPS was developed for the launch and recovery process. The first phase of the CONOPS, which pertains to the position of the REMUS initially on the free surface prior to sling engagement is simulated using ANSYS AQWA. Preprocessing for the simulation involved simplification of the model in ANSYS SpaceClaim to achieve a proper mesh as well as theoretical calculations of the input parameters for wave environment and point masses etc. The simulation was evaluated by taking into consideration two wave environment scenarios: beam sea’s (-90 degrees) and head seas (0 degrees). The wave environment was based on a linear frequency range for the waves which considered wavelengths that correspond to half and double the length of the WAM-V 16’. The significance of the simulation is characterized through identifying the ideal direction and wave frequency range for recovery based on the RAOs of the two vehicles.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014216
Subject Headings: Autonomous underwater vehicles--Design and construction, Marine engineering, Littoral combat ships
Format: Document (PDF)

Title: DEVELOPMENT OF MULTIFUNCTIONAL BETA-TRICALCIUM PHOSPHATE SCAFFOLDS FOR ANGIOGENESIS AND OSTEOGENESIS.
Creator: Qian, Enze, Kang, Yunqing, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Rapid and efficient vascularization is still a considerable challenge of a tissue engineered β-tricalcium phosphate (β-TCP) scaffold. To overcome this challenge, branched channels were created in the porous scaffold to stimulate the instant flow of blood supply. The branched channeled porous β-TCP scaffold was fabricated using 3D printing and template-casting method. Human bone mesenchymal stem cells (hBMSC) and human umbilical vein endothelial cells (HUVEC) were seeded in the scaffolds and...
Show moreRapid and efficient vascularization is still a considerable challenge of a tissue engineered β-tricalcium phosphate (β-TCP) scaffold. To overcome this challenge, branched channels were created in the porous scaffold to stimulate the instant flow of blood supply. The branched channeled porous β-TCP scaffold was fabricated using 3D printing and template-casting method. Human bone mesenchymal stem cells (hBMSC) and human umbilical vein endothelial cells (HUVEC) were seeded in the scaffolds and characterized through double-stranded DNA (dsDNA) assay, alkaline phosphatase (ALP) assay and cell migration. Scaffolds were then implanted in the subcutaneous pockets in mice. Hematoxylin and eosin staining and Immunohistochemical staining on vascularization, bone-related markers were carried out. Results showed that branched channels significantly promoted HUVECs’ infiltration, migration, proliferation, and angiogenesis and also promote the proliferation and osteogenesis differentiation of hBMSCs. Scaffolds did not show significant pro-inflammatory effects. In vivo results showed that in the early stage after implantation, cells significantly migrated into branched channeled scaffolds compared to non-channeled and straight channeled scaffolds. More and matured blood vessels formed in the branched channeled scaffolds compared to in non-channeled and straight channeled scaffolds. Besides promoting vascularization, the branched channels also stimulated the infiltration of bone-related cells into the scaffolds. These results suggested that the geometric design of branched channels in the porous β-TCP scaffold promoted rapid vascularization and potentially stimulated bone cell recruitment. To further enhance the function of the scaffold to promote the MSCs differentiation, MnO2 hollow and solid nanoparticles were doped into the scaffold with different concentrations.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014193
Subject Headings: Tissue engineering, Bone Regeneration, Beta-tricalcium phosphate
Format: Document (PDF)

Title: Embodied Biological Computers: Closing The Loop on Sensorimotor Integration of Dexterous Robotic Hands.
Creator: Ades, Craig, Engeberg, Erik D., Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: The sensation of touch is an integral part of using our hands. As different researchers work toward the restoration of afferent sensation in prosthetic hands, it becomes urgent to better understand how an artificial hand’s afferent inputs are affected by the efferent muscular outputs, and vice-versa. Current methods of neuroprosthetic research have many regulatory hurdles, time, cost, and associated risk to the patient. To circumvent these hurdles, we developed a non-invasive, closed-loop (CL...
Show moreThe sensation of touch is an integral part of using our hands. As different researchers work toward the restoration of afferent sensation in prosthetic hands, it becomes urgent to better understand how an artificial hand’s afferent inputs are affected by the efferent muscular outputs, and vice-versa. Current methods of neuroprosthetic research have many regulatory hurdles, time, cost, and associated risk to the patient. To circumvent these hurdles, we developed a non-invasive, closed-loop (CL) neuroprosthetic research platform, integrating artificial tactile signals from an artificial hand with biomimetically-stimulated biological neuronal networks (BNNs) cultured in a multielectrode array (MEA) chamber. These living embodied biological computers (EBCs) can provide a non-invasive alternative for investigating invasive neuroprosthetic interfaces. With them we can explore a variety of control techniques, tactile sensation encoding methods, and neural decoding methods to increase the rate of research in this area with minimal regulatory approval, greatly reduced cost and time, and no risk to the patients. In the first stage of this integration, our EBC was programmed to embody neuronal spiking from spontaneously active “efferent” receptive fields in cultured BNNs as intentional signals for movement. Bursts were transferred to a robotic hand and initiated a tapping motion of the index finger laid in proximity to a surface. Contact elicited artificial sensations, which were registered by a biotac tactile sensor array fit to the robotic fingertip.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00014092
Subject Headings: Artificial hands, Neuroprostheses, Neurotechnology (Bioengineering), Robotics
Format: Document (PDF)

Title: APPLICATIONS OF DIGITAL HOLOGRAPHIC IMAGING TOWARDS CHARACTERIZATION OF MARINE PLANKTON DISTRIBUTIONS AND BIOPHYSICAL INTERACTIONS.
Creator: Barua, Ranjoy, Nayak, Aditya R., Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Characterization of the distribution and biophysical interactions of oceanic planktonic organisms is crucial to address fundamental science questions associated with climate change, marine ecology, pollution, and ocean optics. Thus, development of instrumentation techniques for monitoring plankton at high spatial and temporal resolutions is important. This dissertation deals with the advancements made in applying digital holography – a 3-D non-intrusive, freestream imaging technique – to...
Show moreCharacterization of the distribution and biophysical interactions of oceanic planktonic organisms is crucial to address fundamental science questions associated with climate change, marine ecology, pollution, and ocean optics. Thus, development of instrumentation techniques for monitoring plankton at high spatial and temporal resolutions is important. This dissertation deals with the advancements made in applying digital holography – a 3-D non-intrusive, freestream imaging technique – to address three different applications associated with marine plankton monitoring and ecology. In the first project, an autonomous in-line digital holographic microscope was successfully deployed for rapid in situ detection of the harmful dinoflagellate, Karenia brevis in the coastal Gulf of Mexico. Monitoring K. brevis abundance and distribution are crucial for early warning systems and implementing preventative measures to limit potential damage. The holographic system was successfully paired with a convolutional neural network for automated data processing to ensure rapid and accurate K. brevis detection.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00014096
Subject Headings: Marine plankton, Holography, Digital holographic microscopy
Format: Document (PDF)

Title: UNDERSTANDING GRAVITY DRIVEN PARTICLE SETTLING AND DISTRIBUITION IN FRACTURES.
Creator: Hafez, Mazen, Kim, Myeongsub, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: The elevated energy demand and high dependency on fossil fuels have directed researchers’ attention to promoting and advancing hydraulic fracturing (HF) operations for a sustainable energy future. Previous studies have demonstrated that the particle suspension and positioning in slick water play a vital role during the injection and shut-in stages of the HF operations. A significant challenge to HF is the premature particle settling and uneven particle distribution in a formation. Even though...
Show moreThe elevated energy demand and high dependency on fossil fuels have directed researchers’ attention to promoting and advancing hydraulic fracturing (HF) operations for a sustainable energy future. Previous studies have demonstrated that the particle suspension and positioning in slick water play a vital role during the injection and shut-in stages of the HF operations. A significant challenge to HF is the premature particle settling and uneven particle distribution in a formation. Even though various research was conducted on the topic of particle transport, there still exist gaps in the fundamental particle-particle interaction mechanisms. This dissertation utilizes both experimental and numerical approaches to advance the state of the art in particle-particle interactions in various test conditions. Experimentally, the study utilizes high-speed imaging coupled with particle tracking velocimetry (PTV) and particle image velocimetry (PIV) to provide a space and time-resolved investigation of both two-particle and multi-particle interactions during gravitational settling, respectively.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00014095
Subject Headings: Hydraulic fracturing, Particle image velocimetry, Particle tracking velocimetry, Fluid mechanics research
Format: Document (PDF)

Title: DATA-DRIVEN IDENTIFICATION AND CONTROL OF TURBULENT STRUCTURES USING DEEP NEURAL NETWORKS.
Creator: Jagodinski, Eric, Verma, Siddhartha, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Wall-bounded turbulent flows are pervasive in numerous physics and engineering applications. Such flows tend to have a strong impact on the design of ships, airplanes and rockets, industrial chemical mixing, wind and hydrokinetic energy, utility infrastructure and innumerable other fields. Understanding and controlling wall bounded turbulence has been a long-pursued endeavor yielding plentiful scientific and engineering discoveries, but there is much that remains unexplained from a...
Show moreWall-bounded turbulent flows are pervasive in numerous physics and engineering applications. Such flows tend to have a strong impact on the design of ships, airplanes and rockets, industrial chemical mixing, wind and hydrokinetic energy, utility infrastructure and innumerable other fields. Understanding and controlling wall bounded turbulence has been a long-pursued endeavor yielding plentiful scientific and engineering discoveries, but there is much that remains unexplained from a fundamental viewpoint. One unexplained phenomenon is the formation and impact of coherent structures like the ejections of slow near-wall fluid into faster moving ow which have been shown to correlate with increases in friction drag. This thesis focuses on recognizing and regulating organized structures within wall-bounded turbulent flows using a variety of machine learning techniques to overcome the nonlinear nature of this phenomenon. Deep Learning has provided new avenues of analyzing large amounts of data by applying techniques modeled after biological neurons. These techniques allow for the discovery of nonlinear relationships in massive, complex systems like the data found frequently in fluid dynamics simulation. Using a neural network architecture called Convolutional Neural Networks that specializes in uncovering spatial relationships, a network was trained to estimate the relative intensity of ejection structures within turbulent flow simulation without any a priori knowledge of the underlying flow dynamics. To explore the underlying physics that the trained network might reveal, an interpretation technique called Gradient-based Class Activation Mapping was modified to identify salient regions in the flow field which most influenced the trained network to make an accurate estimation of these organized structures. Using various statistical techniques, these salient regions were found to have a high correlation to ejection structures, and to high positive kinetic energy production, low negative production, and low energy dissipation regions within the flow. Additionally, these techniques present a general framework for identifying nonlinear causal structures in general three-dimensional data in any scientific domain where the underlying physics may be unknown.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00014119
Subject Headings: Turbulent flow, Turbulence, Neural networks (Computer science), Deep learning (Machine learning)
Format: Document (PDF)

Title: Swimming control of an underwater vessel with elongated ribbon fin propulsion.
Creator: Uddin, Mohammad Irfan, Curet, Oscar M., Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Navigation of unmanned underwater vehicles in coastal zones, tight spaces and close to structures such as ports, ship hulls and pipelines remains a difficult challenge. Currently Autonomous Underwater Vehicles (AUVs) use a variety of techniques for motion control, including single thrusters with diving planes or hydrofoils, robotic wrists, or a moving mass. However, these techniques provide limited maneuverability. The objective of this work was to understand the mechanics of elongated fin...
Show moreNavigation of unmanned underwater vehicles in coastal zones, tight spaces and close to structures such as ports, ship hulls and pipelines remains a difficult challenge. Currently Autonomous Underwater Vehicles (AUVs) use a variety of techniques for motion control, including single thrusters with diving planes or hydrofoils, robotic wrists, or a moving mass. However, these techniques provide limited maneuverability. The objective of this work was to understand the mechanics of elongated fin propulsion for swimming and motion control of underwater vehicles. This bio-inspired propulsion is used by several fishes that swim by undulating a thin and elongated median fin that allow them to perform forward and directional maneuvers. In the first chapter we present the literature review as well as the mathematical formulation using thrust vectoring approach to achieve forward and turning maneuvers. In the second chapter, we used a robotic vessel with elongated fin propulsion to determine the thrust scaling and efficiency. Using precise force and swimming kinematics measurements with the robotic vessel, the thrust generated by the undulating fin was found to scale with the square of the relative velocity between the free streaming flow and the wave speed. In addition, a hydrodynamic efficiency is presented based on propulsive force measurements and a model on the power required to oscillate the fin laterally.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00014117
Subject Headings: Autonomous underwater vehicles, Biomimetics, Underwater propulsion
Format: Document (PDF)

Title: Wall Pressure Fluctuation in a Turbulent Channel Flow.
Creator: Denissova, Lyubov, Glegg, Stewart, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Turbulent flow is a complex three dimensional system of velocity and pressure fluctuations in a fluid that creates vorticity, eddies and other flow structures. In this study we are specifically concerned with the surface pressure fluctuations below a turbulent boundary layer which is one of the primary sources of panel vibration on aircraft fuselages and ship hulls as well a major issue in ship hydrodynamics. The most accepted analytical approaches to describe the surface pressure...
Show moreTurbulent flow is a complex three dimensional system of velocity and pressure fluctuations in a fluid that creates vorticity, eddies and other flow structures. In this study we are specifically concerned with the surface pressure fluctuations below a turbulent boundary layer which is one of the primary sources of panel vibration on aircraft fuselages and ship hulls as well a major issue in ship hydrodynamics. The most accepted analytical approaches to describe the surface pressure fluctuations are the Chase model [1] for the surface pressure wavenumber spectrum and Goody’s model [2] for the pressure spectrum at a point. The most accurate numerical approach to use is Direct Numerical Simulations (DNS) [3]. In this study we compared Chase and Goody’s models against DNS of a turbulent channel flow in the space–time and wavenumber-frequency domains and estimated regions of convergence between the analytical models and the DNS data.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00014034
Subject Headings: Turbulence, Turbulent boundary layer, Pressure
Format: Document (PDF)

Title: DESIGN, SIMULATION, AND TESTING OF A CVT BASED PTO AND CONTROLLER FOR A SMALL SCALE MHK-TURBINE IN LOW FLOW SPEED OPERATION.
Creator: Hall, Adam, Dhanak, Manhar, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: The aim of this thesis project was to design, develop, and test, a continuously variable transmission (CVT)-based power take off (PTO) sub-system, and its controller, for a small scale marine hydrokinetic turbine (MHK) developed for low-speed tidal currents. In this thesis, a CVT based PTO and controller was developed for a predefined MHK and validated through simulations. A testing platform was subsequently developed including an emulation system to replicate the MHK for testing of the...
Show moreThe aim of this thesis project was to design, develop, and test, a continuously variable transmission (CVT)-based power take off (PTO) sub-system, and its controller, for a small scale marine hydrokinetic turbine (MHK) developed for low-speed tidal currents. In this thesis, a CVT based PTO and controller was developed for a predefined MHK and validated through simulations. A testing platform was subsequently developed including an emulation system to replicate the MHK for testing of the coupled MHK/PTO system. Laboratory testing of the emulation system, PTO component efficiencies, and full system with controls was then conducted. The results showed the mechanical PTO design to be a valid solution and the control methods to be marginally stable with adequate power conversion at low-speed current conditions. The results also identified future work in continued controller development, alternate PTO component testing, and continued testing in parallel with that being done on the MHK prototype.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00013977
Subject Headings: Marine turbines--Design and construction, Marine turbines--Transmission devices, Marine turbines--Testing
Format: Document (PDF)

Title: Characterization of A Stereo Vision System For Object Classification For USV Navigation.
Creator: Kaplowitz, Chad, Dhanak, Manhar, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: This experiment used different methodologies and comparisons that helped to determine the direction of future research on water-based perception systems for unmanned surface vehicles (USV) platforms. This would be using a stereo-vison based system. Presented in this work is object color and shape classification in the real-time maritime environment. This was coupled with HSV color space that allowed for different thresholds to be identified and detected. The algorithm was then calibrated and...
Show moreThis experiment used different methodologies and comparisons that helped to determine the direction of future research on water-based perception systems for unmanned surface vehicles (USV) platforms. This would be using a stereo-vison based system. Presented in this work is object color and shape classification in the real-time maritime environment. This was coupled with HSV color space that allowed for different thresholds to be identified and detected. The algorithm was then calibrated and executed to configure the depth, color and shape accuracies. The approach entails the characterization of a stereo-vision camera and mount that was designed with 8.5° horizontal viewing increments and mounted on the WAMV. This characterization has depth, color and shape object detection and its classification. Different shapes and buoys were used to complete the testing with assorted colors and shapes. The main program used was OpenCV which entails Gaussian blurring, Morphological operators and Canny edge detection libraries with a ROS integration. The code focuses on the area size and the number of contours detected on the shape for successes. A summary of what this thesis entails is the installation and characterization of the stereovision system on the WAMV-USV by obtaining specific inputs to the high-level controller.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00014035
Subject Headings: Computer vision, Unmanned surface vehicles
Format: Document (PDF)

Title: DEVELOPMENT OF A SLIDING MODE CONTROLLER AND CONTROL ALLOCATION OPTIMIZED FOR ELECTRO-MAGNETIC ACTUATOR LIMITATIONS.
Creator: Resio, Daniel, Dhanak, Manhar, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: This thesis presents the development a sliding mode controller and vehicle allocation to control a surface vessel platform within a high degree of accuracy. This is part of ongoing development on the WAMV platform at Florida Atlantic University to improve autonomy in marine systems. By developing models for the untested thrusters currently used, the efficacy of a Sliding Mode Controller is evaluated, and a new control allocation developed based on the gradient descent optimization method is...
Show moreThis thesis presents the development a sliding mode controller and vehicle allocation to control a surface vessel platform within a high degree of accuracy. This is part of ongoing development on the WAMV platform at Florida Atlantic University to improve autonomy in marine systems. By developing models for the untested thrusters currently used, the efficacy of a Sliding Mode Controller is evaluated, and a new control allocation developed based on the gradient descent optimization method is developed to manage the thrusters’ constrained angles of thrust generation. The official simulation for the WAMV platform was then modified to include these aspects and the system was tested under wind conditions and was successful in achieving control to waypoints. The gradient descent optimization used for the control allocation did manage to increase the accuracy of both heading and position of the system at convergence. The sliding mode controller navigated to the desired waypoint however maintained oscillations of cross track that were less then 2m and heading error less 20 degrees.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00014037
Subject Headings: Unmanned surface vehicles, Actuators, Sliding mode control
Format: Document (PDF)

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