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Title: Risk-Benefit Analysis and Optimization of LEED-Certified School Buildings Design and Construction: Statisitical and Machine Learning Approaches.
Creator: Doczy, Ryan Daniel, Boot, Walter Richard, Sobanjo, John Olusegun, Spainhour, Lisa, Florida State University, College of Engineering, Department of Civil and Environmental...
Show moreDoczy, Ryan Daniel, Boot, Walter Richard, Sobanjo, John Olusegun, Spainhour, Lisa, Florida State University, College of Engineering, Department of Civil and Environmental Engineering
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Abstract/Description: As the strategy of green building becomes more and more popular due to a combination of environmental and economic concerns, there develops a need for clearly being able to understand the potential implications for choosing green strategies over conventional building practices. Some of the regions of interest consist of the additional upfront costs associated with green practices, potential life-cycle benefits associated with green building components, potential energy savings, and the...
Show moreAs the strategy of green building becomes more and more popular due to a combination of environmental and economic concerns, there develops a need for clearly being able to understand the potential implications for choosing green strategies over conventional building practices. Some of the regions of interest consist of the additional upfront costs associated with green practices, potential life-cycle benefits associated with green building components, potential energy savings, and the ability to reduce emissions. Many of these areas can potentially be forecasted with a fair degree of certainty (e.g. energy consumption, additional upfront costs); however, some elements of green building are less well defined. One such area consists of the ability of green buildings to improve the productivity and well-being of its inhabitants through an improved indoor environmental quality (IEQ). It is difficult to grasp just how much a healthier and cleaner environmental can impact a person’s cognitive functions, mental state, and physical health. Several studies shown in the literature review of this paper lead show a positive correlation between green buildings and reductions in asthma symptoms, depression symptoms, improved well-being due to reductions in contaminants, a reduction in sick building syndrome (SBS) and building related illness (BRI). This paper aims to do what many have done before in attempting to quantify the potential impact that sustainable buildings can have on its occupants; however, the scope and methods to determine these potential correlations will differ. Perhaps the most noticeable difference will be in the paper’s focus on attempting to measure the potential impact that LEED (Leadership in Energy and Environmental Design) accredited schools have on their student occupants by measuring their productivity via the use of standardized test scores and attendance rates compared to those students in conventional (non-LEED) schools. To develop a balanced analysis, the paper will control for various school-related and socio-economic factors (e.g. economic status, race, percent of teachers with a Master’s degree or higher). To make a judgement on the effect that sustainability has on academic achievement and student wellbeing, 2 sample t-tests, regression analysis, and M5P decision trees will be implemented to determine if there are significant differences between LEED and conventional schools and to determine the relationship between LEED and non-LEED parameters on student achievement and wellbeing metrics. To ensure that a large population of students from across the nation are accounted for, the study intends on investigating at least three states-worth of student data. These states (Florida, New York and Virginia) are in different climates, thus allowing for an examination of the potential differences between the various climate zones and building codes. Lastly, a case study building information model (BIM) of College Park Elementary School (located in Virginia) will be run through the energy modeling (EM) software, Ecotect, to provide information related to the school’s annual energy consumption, acoustics, and daylight and lighting values. An optimization equation, developed using previous literature and findings from this study, will use information from the case study in an attempt to optimize its academic performance. The equation will attempt to minimize construction and operational costs while maximizing student performance metrics. The optimization equation will be run through NEOS server’s Nonlinearly Constrained Optimization, Knitro. The purpose of this study is to inform those decision-makers involved in the construction of schools, and who may be interested in obtaining LEED certification for the school, to what extent the LEED schools benefit the school’s student academic achievement levels. Accounting for soft benefits (e.g. productivity, morale, general wellbeing) in a cost-benefit analysis invites an element of risk due to the difficulties in soliciting, obtaining, and accurately measuring these performance metrics. When considering fields involving knowledge work, accurately measuring productivity is an inexact science that normally requires building occupants to perform self-examinations. The results from these examinations are reliant on the occupant’s perceptions and could be open to bias. This study avoids self-assessments through its use of standardized testing as a measure for productivity. The proposed outcome of this paper is that the impacts of LEED schools on their occupants’ academic achievement, health, and wellbeing will be better understood and easier to quantify. The authors hypothesize that LEED schools will outperform conventional schools, which can be attributed to improved IEQ due to tighter building envelopes, increased ventilation rates, better filtration, a reduction in building or cleaning products containing volatile organic compounds, etc. An absence of this data could point to the inability of LEED schools to directly impact their students in a meaningful way, particularly its Indoor Environmental Quality credits, which means that LEED could have to rethink its standards if it wishes to truly improve the productivity and wellbeing of its occupants.
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Date Issued: 2018
Identifier: 2018_Su_Doczy_fsu_0071E_14648
Format: Thesis

Title: Investigation of the Osmotic Drying of Alumina-Gelatin Objects Utilizing an Aqueous Poly(Ethylene glycol) Liquid Desiccant.
Creator: Hammel, Emily Catherine, Okoli, Okenwa O. I., Hruda, Simone Peterson, Liang, Zhiyong, Zhang, Mei, Florida State University, College of Engineering, Department of Industrial and...
Show moreHammel, Emily Catherine, Okoli, Okenwa O. I., Hruda, Simone Peterson, Liang, Zhiyong, Zhang, Mei, Florida State University, College of Engineering, Department of Industrial and Manufacturing Engineering
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Abstract/Description: Advanced ceramics and ceramic composites have a variety of advantageous properties, such as high hardness, strength, and wear resistance. This makes them good candidates for materials in the aerospace, automotive and defense industries, among others. A major disadvantage of advanced ceramics and ceramic composites is their requirement for specialized processing which often makes manufacturing complex shaped ceramic objects challenging and costly. Additionally, these materials are susceptible...
Show moreAdvanced ceramics and ceramic composites have a variety of advantageous properties, such as high hardness, strength, and wear resistance. This makes them good candidates for materials in the aerospace, automotive and defense industries, among others. A major disadvantage of advanced ceramics and ceramic composites is their requirement for specialized processing which often makes manufacturing complex shaped ceramic objects challenging and costly. Additionally, these materials are susceptible to flaw incorporation during production. These flaws are initiation points for failure and thus lead to a drastic reduction in strength. Repeatable manufacturing methods and optimized processes are compulsory for cost saving and production of high quality parts. In recent years, new processing technologies, such as gelcasting, have been developed to accommodate the formation of complex shaped ceramics and also the manufacture of ceramic composites. The use of wet forming technologies, like slip casting or gelcasting, necessitates the careful drying of ceramic objects. Complex shaped objects are particularly difficult to properly dry without introducing internal stresses which may result in warping and cracking, thus rendering the object unusable. Additionally, traditional drying processes are often energy intensive and lengthy, neither of which are favorable in a production setting. To improve manufacturability, the processing-structure-property relationships developed during the drying process must be investigated further. This work addresses the need to define optimized process conditions for the drying of alumina objects gelcast using gelatin. The osmotic drying process was employed to remove solvent from the objects through the use of an aqueous liquid desiccant solution of poly(ethylene glycol) (PEG). The process settings for the solution’s osmotic pressure and molecular weight were investigated, in addition to the total immersion time. The mass transfer processes that occurred between the ceramic object and the liquid desiccant solution were quantified in several case studies. For one sample, 40 weight% of the initial water content was removed in 75 minutes demonstrating the potential drying efficiency of this method. Depending on the initial solution conditions, the PEG solute was found to diffuse into the ceramic object to varying degrees. The effect of the drying condition on the object’s density and hardness was also measured. Through the development of regression equations, the process settings were optimized based on the goals to maximize water loss, minimize solids gain, and maximize the object’s density. The optimum drying settings for the objects studied in this work were an osmotic pressure of 2.50 MPa, a molecular weight of at least 100,000 g/mol, and an immersion time of 60 minutes. When objects of similar geometry, composition, and solution-to-object volume ratio are immersed in this type of solution, they are expected to lose 28 weight% of the object’s initial water content, gain solids of 0.82 weight% of the object’s initial mass, and have a density of 3.54 g/cm3. Furthermore, the regression models were validated using an independent experimental study. A model based on mass balance was used to define the kinetics of the mass transfer, along with the equilibrium values. Lastly, a demonstration of the feasibility of combining gelcasting, osmotic drying, and sacrificial templating is presented. Overall, these results may be used as the basis for further investigation into the scale up of the osmotic drying of gelcast alumina with the eventual implementation of the process in an industrial setting.
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Date Issued: 2018
Identifier: 2018_Su_Hammel_fsu_0071E_14711
Format: Thesis

Title: Flow Physics and Nonlinear Dynamics of Separated Flows Subject to ZNMF-Based Control.
Creator: Deem, Eric Anthony, Cattafesta, Louis N., Sussman, Mark, Taira, Kunihiko, Collins, E., Moore, Matthew Nicholas J., Hemati, Maziar, Florida State University, College of...
Show moreDeem, Eric Anthony, Cattafesta, Louis N., Sussman, Mark, Taira, Kunihiko, Collins, E., Moore, Matthew Nicholas J., Hemati, Maziar, Florida State University, College of Engineering, Department of Mechanical Engineering
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Abstract/Description: Aircraft, turbomachinery, wind turbines, and other systems that generate or rely on aerodynamic forces are designed to operate most efficiently when flows are fully attached. However, especially due to increasing off-design performance requirements, there is significant risk of inefficient operation or failure due to flow separation. This work formulates a procedure for extending the performance envelope of many fluidic systems by delaying flow separation through real time separated flow...
Show moreAircraft, turbomachinery, wind turbines, and other systems that generate or rely on aerodynamic forces are designed to operate most efficiently when flows are fully attached. However, especially due to increasing off-design performance requirements, there is significant risk of inefficient operation or failure due to flow separation. This work formulates a procedure for extending the performance envelope of many fluidic systems by delaying flow separation through real time separated flow state estimation and control. The history of active separation control is rich; however the approach presented here is novel in that it employs "real time" dynamical system updates to track nonlinear variations in the flow and provide robustness to flow state conditions. First, the dynamics of the canonical laminar separated flow over a flat plate at Rec=10⁵ are characterized by employing full-field, time-resolved PIV and unsteady surface pressure measurements. Dynamic Mode Decomposition (DMD) is employed on the high dimensional PIV velocity fields to identify the dynamically relevant spatial structure and temporal characteristics of the separated flow. Then, results of various cases of open-loop control using a zero-net mass flux actuator slot located just upstream of separation are presented that show separation reduction occurs for the employed actuation method. Real time estimates of the dynamical characteristics are provided by performing online DMD on measurements from a linear array of unsteady surface pressure transducers. The results show that online DMD of the pressure measurements provides reliable estimates of the modal characteristics of the separated flow subject to forcing. Furthermore, the dynamical estimates are updated at a rate commensurate with the characteristic time scales of the flow. Therefore, as the separated flow reacts to the applied forcing, online DMD applied to the surface pressure measurements provides a time-varying linear estimate of the evolution of the flow. Building upon these results, methods for adaptive control of flow separation based on the model provided by online DMD are formulated and implemented on the separated flow. Feedback control is implemented in which Linear Quadratic Regulator gains are computed recursively as the model provided by online DMD is updated. This physics-motivated, autonomous approach results in more efficient flow reattachment, requiring approximately 30% less actuator effort as compared with the commensurate open loop forcing case. Since this approach relies solely on observations of the separated flow, it is robust to variable flow conditions. Additionally, this approach does not require prior knowledge of the characteristics of the separated flow.
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Date Issued: 2018
Identifier: 2018_Su_Deem_fsu_0071E_14530
Format: Thesis

Title: Impact of Connected and Autonomous Vehicles on Freeway Traffic Operations.
Creator: Theophilus, Oluwatosin Paul, Sobanjo, John Olusegun, Ozguven, Eren Erman, Dulebenets, Maxim A., Florida State University, College of Engineering, Department of Civil and...
Show moreTheophilus, Oluwatosin Paul, Sobanjo, John Olusegun, Ozguven, Eren Erman, Dulebenets, Maxim A., Florida State University, College of Engineering, Department of Civil and Environmental Engineering
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Abstract/Description: This project evaluates using traffic simulation, the performance of a mixed traffic composition of Connected and Autonomous Vehicles (CAV) and conventional or human-driven vehicles, in comparison with the performance of the existing traffic composition of only conventional vehicles on a freeway segment. The introduction of CAVs into the existing transportation system is a phase in the evolution of automobile traffic currently generating a lot of concerns and questions that needs to be...
Show moreThis project evaluates using traffic simulation, the performance of a mixed traffic composition of Connected and Autonomous Vehicles (CAV) and conventional or human-driven vehicles, in comparison with the performance of the existing traffic composition of only conventional vehicles on a freeway segment. The introduction of CAVs into the existing transportation system is a phase in the evolution of automobile traffic currently generating a lot of concerns and questions that needs to be answered before the full deployment of these vehicles. Traffic simulation presents a safer and cost-effective approach to evaluating this innovative technology when compared with real world testing. Connected and autonomous vehicles (CAV) are designed to improve traffic operations, as the difference in their driving behavior from regular vehicles suggests a reasonable tendency to change the traffic flow pattern. However the issue being examined in this project is whether there would be a significant change in traffic operations resulting from their deployment, and also to verify whether the change is an improvement of the existing traffic condition in terms of performance measures used for the evaluation. Data was collected from the I-95 Freeway in South Florida, and used in the development of a traffic microsimulation model, in VISSIM. The model was calibrated using minimum error algorithm implemented in MATLAB to determine the optimal value of the two model parameters considered -- stand still distance (CC0), and headway time (CC1). The calibrated model was used as the base model and CAVs are incorporated into the base model in 10% increment, to examine their effect on the base model. The performance measures are average hourly speed, hourly traffic volume, travel time, delay, and safety. Findings show that for every increment in CAV market penetration, there is a change of 6.52% - 48% in the capacity of the freeway, 40% reduction in travel time, more than 30% reduction in delay per vehicle, more than 26% increase in average speed of the traffic at high demand volumes.
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Date Issued: 2018
Identifier: 2018_Su_Theophilus_fsu_0071N_14809
Format: Thesis

Title: Impedance Measurement Techniques in Noisy Medium Voltage Power Hardware-in-the-Loop Environments.
Creator: Chauncey, Gunnar Luke, Li, Hui, Steurer, Michael, Yu, Ming, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: In Power Hardware-In-The-Loop (PHIL) simulations, it is important to understand the impedance characteristics of the system being tested. These impedances are used in the assessment of both the stability and the accuracy of the PHIL simulation experiment, as well as for stability analyses for the integration of the device under test (DUT) into the eventual system of deployment. When testing medium voltage systems in the megawatt power range, sensor noise stemming from the switching amplifiers...
Show moreIn Power Hardware-In-The-Loop (PHIL) simulations, it is important to understand the impedance characteristics of the system being tested. These impedances are used in the assessment of both the stability and the accuracy of the PHIL simulation experiment, as well as for stability analyses for the integration of the device under test (DUT) into the eventual system of deployment. When testing medium voltage systems in the megawatt power range, sensor noise stemming from the switching amplifiers can become quite an issue. This thesis evaluates four different impedance measurement techniques to find a reliable, accurate, and quick assessment over a wide frequency range in the noisy environments of medium voltage systems. (1) a single tone consisting of one sine wave at a single frequency, (2) a multitoned signal which is the sum of multiple sine waves, each at a unique frequency, (3) a frequency-swept sine wave, also known as a “chirp”, and (4) a pseudorandom binary sequence. Each of these signals are injected into the system while energized in order to measure the response, which is then processed for the impedance characteristics. Various tests are conducted to simulated systems with simulated sensor noise to determine the viability of each of the techniques. Once the techniques are determined to be appropriate signals for system characterization in noisy medium voltage systems, they will be applied to a simulated Multilevel Modular Converter (MMC) model. The data from the simulated model will then be verified with a hardware experimental verification test with the viable signals chosen.
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Date Issued: 2018
Identifier: 2018_Su_Chauncey_fsu_0071N_14782
Format: Thesis

Title: Network-Theoretic and Data-Based Analysis and Control of Unsteady Fluid Flows.
Creator: Nair, Aditya Gopimohan, Taira, Kunihiko, Sussman, Mark, Cattafesta, Louis N., Oates, William, Alvi, Farrukh S., Brunton, Steven L. (Steven Lee), Florida State University,...
Show moreNair, Aditya Gopimohan, Taira, Kunihiko, Sussman, Mark, Cattafesta, Louis N., Oates, William, Alvi, Farrukh S., Brunton, Steven L. (Steven Lee), Florida State University, College of Engineering, Department of Mechanical Engineering
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Abstract/Description: Unsteady fluid flows have complex dynamics due to the nonlinear interactions amongst vortical elements. In this thesis, a network-theoretic framework is developed to describe vortical and modal (coherent structure) interactions in unsteady fluid flows. A sparsified-dynamics model and a networked-oscillator model describe the complex dynamics in fluid flows in terms of vortical and modal networks, respectively. Based on the characterized network interactions, model-based feedback control laws...
Show moreUnsteady fluid flows have complex dynamics due to the nonlinear interactions amongst vortical elements. In this thesis, a network-theoretic framework is developed to describe vortical and modal (coherent structure) interactions in unsteady fluid flows. A sparsified-dynamics model and a networked-oscillator model describe the complex dynamics in fluid flows in terms of vortical and modal networks, respectively. Based on the characterized network interactions, model-based feedback control laws are established, particularly for controlling the flow unsteadiness. Furthermore, to characterize model-free feedback control laws for suppressing flow separation in turbulent flows, a data-driven approach leveraging unsupervised clustering is developed. This approach alters the Markov transition dynamics of fluid flow trajectories in an optimal manner using a cluster-based control strategy. To describe vortical interactions, dense fluid flow graphs are constructed using discrete point vortices as nodes and induced velocity as edge weights. Sparsification techniques are then employed on these graph representations based on spectral graph theory to construct sparse graphs of the overall vortical interactions which maintain similar spectral properties as the original setup. Utilizing the sparse vortical graphs, a sparsified-dynamics model is developed which drastically reduces the computational cost to predict the dynamical behavior of vortices, sharing characteristics of reduced-order models. The model retains the nonlinearity of the interactions and also conserves the invariants of discrete vortex dynamics. The network structure of vortical interactions in two-dimensional incompressible homogeneous turbulence is then characterized. The strength distribution of the turbulence network reveals an underlying scale-free structure that describes how vortical structures are interconnected. Strong vortices serve as network hubs with smaller and weaker eddies predominantly influenced by the neighboring hubs. The time evolution of the fluid flow network informs us that the scale-free property is sustained until dissipation overtakes the flow physics. The types of perturbations that turbulence network is resilient against is also examined. To describe modal interactions in fluid flows, a networked-oscillator-based analysis is performed. The analysis examines and controls the transfer of kinetic energy for periodic bluff body flows. The dynamics of energy fluctuations in the flow field are described by a set of oscillators defined by conjugate pairs of spatial POD modes. To extract the network of interactions among oscillators, impulse responses of the oscillators to amplitude and phase perturbations are tracked. Using linear regression techniques, a networked oscillator model is constructed that reveals energy exchanges among the modes. In particular, a large collection of system responses are aggregated to capture the general network structure of oscillator interactions. The present networked oscillator model describes the modal perturbation dynamics more accurately than the empirical Galerkin reduced-order model. The linear network model for nonlinear dynamics is subsequently utilized to design a model-based feedback controller. The controller suppresses the modal fluctuations and amplitudes that result in wake unsteadiness leading to drag reduction. The strength of the approach is demonstrated for a canonical example of two-dimensional unsteady flow over a circular cylinder. The network-based formulation enables the characterization and control of modal interactions to control fundamental energy transfers in unsteady bluff body flows. Finally, unsupervised clustering and data-driven optimization of coarse-grained control laws is leveraged to manipulate post-stall separated flows. Optimized feedback control laws are deduced in high-fidelity simulations in an automated, model-free manner. The approach partitions the baseline flow trajectories into clusters, which corresponds to a characteristic coarse-grained phase in a low-dimensional feature space constituted by feature variables (sensor measurements). The feedback control law is then sought for each and every cluster state which is iteratively evaluated and optimized to minimize aerodynamic power and actuation power input. The control optimally transforms the Markov transition network associated with the baseline trajectories to achieve desired performance objectives. The approach is applied to two and three-dimensional separated flows over a NACA 0012 airfoil at an angle of attack of 9° Reynolds number Re = 23000 and free-stream Mach number M∞ = 0.3. The optimized control law minimizes power consumption for flight enabling flow to reach a low-drag state. The analysis provides insights for feedback flow control of complex systems characterizing global cluster-based control laws based on a data-driven, low-dimensional characterization of fluid flow trajectories. In summary, this thesis develops a novel network-theoretic and data-based framework for analyzing and controlling fluid flows. The framework incorporates advanced mathematical principles from network science, graph theory and dynamical systems to extract fundamental interactions in fluid flows. On manipulating these interactions, wake unsteadiness in bluff body flow is reduced leading to drag reduction. Finally, data-based methods are developed to deduce optimal feedback control laws for post-stall separated flows. The network-theoretic and data-based approaches provides insights on fundamental interactions in fluid flows which paves the way for design of novel flow control strategies.
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Date Issued: 2018
Identifier: 2018_Su_Nair_fsu_0071E_14745
Format: Thesis

Title: A New Two-Stage Game Framework for Power Demand Response Management in Smart Grids.
Creator: Fan, Huipu, Yu, Ming, Liu, Xiuwen, Tung, Leonard J., Andrei, Petru, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: Recently, the smart grid technologies have been developed rapidly recently, which an important component is the so called demand response management (DRM). With the help of a DRM program, a utility company can adjust the power demand and electricity price to reduce the cost of power generation and consumption. However, there are many problems in DRM need to be solved. For example, to solve the problem of optimizing a generator's power (GP), the conventional methods such as economic dispatch ...
Show moreRecently, the smart grid technologies have been developed rapidly recently, which an important component is the so called demand response management (DRM). With the help of a DRM program, a utility company can adjust the power demand and electricity price to reduce the cost of power generation and consumption. However, there are many problems in DRM need to be solved. For example, to solve the problem of optimizing a generator's power (GP), the conventional methods such as economic dispatch (EDP) may reduce the profit of the utility company. To solve the problem of optimizing a consumer's power (CP), the existing smart pricing strategies may reduce the long-term benefits of the customers. This dissertation aims to develop a two-stage game model to increase the profit of the utility company and while increase the long-term benefit of the customers. For solving the GP. It is critical for the power generator and utility company to allocate the power demand properly, but the profit for the utility company may be reduced. To solve the CP, it is difficult for the customers to achieve a long-term beneficial power-usage-pattern with myopic pricing strategies. The stability of the smart grid and the benefit of the customers may also be reduced due to the myopic pricing strategies. It is difficult for the utility company to use the existing methods (e.g., EDP) to order an optimal power demand from the power generators to earn the maximum profit. There are two issues that are needed to be solved in the GP. First, the weight function for the utility company and power generators in the GP is not established properly in the existing methods. For example, the value of the weight function for the utility company and power generators are usually the same in an EDP method. However, in a smart grid, the utility company has the privilege to demand the power while the power generators must follow the demand. Hence the value of weight function for the utility company should be greater than the one for the power generators in a GP. Second, the optimal demand for the utility company is most likely not the optimal generation for the generators. The imbalanced power will increase the generation cost significantly. It is also difficult for a utility company to maintain an efficient DRM for a long-time period by using the existing smart pricing strategies. Applying incentive is the major solution for the utility company to influence the power demand of a customer. However, the traditional pricing strategies are shortsightedly designed, by which the long-time efficiency for the DRM is reduced. For example, the trigger punishment strategy applies a punishing price to a customer for a long period when a non-cooperation behavior is detected. During the punishment period, the customer chooses its power consumption freely since the punishment will be applied anyway. Such selfish behaviors reduce the long-term efficiency for the DRM and the stability of the smart grid. In this dissertation, we propose a two-stage game model to solve the GP and CP to increase the long-term efficiency for the DRM, maintain the stability of the smart grid, and also increase the profit of the utility company. In the first stage, a Stackelberg game model is applied to solve the GP, in which the utility company is the leading player while the generators are the following players. We prove that the GP for the following players is a convex problem mathematically. The following players achieve the Nash equilibrium (NE) state by choosing the unique optimal generation. The leading player reacts with this unique generation to achieve the optimal profit. Both the leading and following players reach an agreement in the NE state, in which they have no motivation to deviate the optimal actions. A genetic algorithm is developed to obtain the optimal demand for the leading and following players. In addition, we introduce a power balance constraint to the leading and following players to avoid the cost caused by the imbalanced power. By applying the constraint, the generated power is equal to the demand all the time. The smart grid will not need to store the excessive power in the energy storage unit or send the power back to the power generators to keep them idling. The cost is avoided and the efficiency of the DRM is increased. In the second stage, a repeated game model is applied to solve the CP, in which the customers are the players. The strategy for the players is to minimize the individual power consumption of each customer. The utility function for the players is the cost of the customers. The objective for the players is to minimize the cost. In this work, we prove that the NE state exists for the repeated game. However, it has been shown that in the NE state, the players' myopic behaviors may reduce the benefits for the entire group of players. To avoid the loss, we use a genetic algorithm to find the Pareto-efficient solution for the players, in which no player can increase its benefit by reducing other players' benefit. We apply a Tit-for-Tat (TFT) smart pricing strategy to increase the punishment strength from the utility company. Once an irrational behavior from a player is detected, a punishment will be applied to the player for a short period of time. The player can choose to cooperate or not during the punishment period. Compared to the existing smart pricing strategies, the long-term benefit for the smart grid is increased by applying the TFT strategy to the customers. The numerical simulations in different scenarios are conducted to evaluate the performance of the proposed two-stage game framework by using MATLAB. All the parameters and constraints of the related components are from the Department of Energy's report and the Oasisui online database. Five power generators, one utility company, and one hundred customers have been used in the simulations. Compared with the existing solutions (e.g., EDP and gaming optimization), the cost in power consumption is reduced by 6% percent while the profit for power generation is increased by 8% percent in our test scenarios. With the help of the proposed model, we enhance the efficiency for the DRM. The peak-to-average ratio (PAR) of the power demand of our work is compared with the EDP method. The effect of the PAR is studied. The numerical results show that the proposed model has a similar PAR to that of the EDP method, which implies that the proposed model has no negative influence on the stability of the smart grid. The punishing effort of the TFT strategy is compared with the trigger strategy (TP) to study the punishment influence on the customers. The numerical results show that the customers who are applied with the TFT strategy are more willing to cooperate with the utility company. The impact of the power loss ratio and different types of customers is also simulated and analyzed. The simulation results show that the players with a greater transmission loss ratio are more willing to cooperate. The customers that are associated with a greater linear dissatisfaction coefficient are more concerned about the dissatisfaction cost. The customers with greater price-sensitive coefficients are more concerned about the consumption cost. In summary, compared to the existing solutions, the proposed two-stage game model improves the performance of the DRM while maintain the stability of the smart grid. We also discuss the future research issues in the related areas.
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Date Issued: 2018
Identifier: 2018_Su_Fan_fsu_0071E_14654
Format: Thesis

Title: Distributed Adaptive Droop Control for Power Management in DC Distribution Systems.
Creator: Perkins, Dallas, Edrington, Christopher S., Ordóñez, Juan Carlos, Foo, Simon Y., Moss, Pedro L., Florida State University, College of Engineering, Department of Electrical and...
Show morePerkins, Dallas, Edrington, Christopher S., Ordóñez, Juan Carlos, Foo, Simon Y., Moss, Pedro L., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: The current trend for naval destroyer-class ships is the move toward DC distribution systems as the next generation of ships is developed. The main motivation for using DC is to increase the power density of the ships to accommodate advanced weaponry such as the electromagnetic railgun. The distribution systems are also expected to be modular and plug-n-play in nature, leading toward a distributed control scheme to integrate the distributed sources and loads that could be online at any given...
Show moreThe current trend for naval destroyer-class ships is the move toward DC distribution systems as the next generation of ships is developed. The main motivation for using DC is to increase the power density of the ships to accommodate advanced weaponry such as the electromagnetic railgun. The distribution systems are also expected to be modular and plug-n-play in nature, leading toward a distributed control scheme to integrate the distributed sources and loads that could be online at any given time. One of the main performance requirements for the future power distribution systems is the ability to accurately share power among the distributed resources on the ship, while also maintaining the voltage stability of the distribution system, often referred to as power management. The primary candidate to accomplish the power management of the ship systems is droop control. Droop control has been extensively studied for terrestrial applications for sharing power between paralleled sources. Specifically, its application to DC microgrids is of interest since islanded microgrids have similar properties to ship systems. In these studies, it has been shown that conventional droop control is limited in its power sharing capabilities due to a tradeoff between the accuracy of the power sharing between devices and the regulation of the bus voltage. Secondary controllers have been proposed to modify the droop control scheme to alleviate these issues based on linear controllers or heuristic methods. However, accurate models for DC microgrids are difficult to derive for linear control design, and heuristic methods do not present an autonomous way to adjust the parameters of the controller. Therefore, adaptive control is proposed to adjust the droop controller’s parameters in an online fashion to find the optimal values based on the system conditions. Model reference adaptive control is chosen in this research for its ability to deal with system uncertainties and ensure stability. Specifically, combined model reference adaptive control is chosen for its improvements in transient response and robustness over the direct and indirect versions. The method is developed and simulated using MATLAB/Simulink to determine the performance of the algorithm. Additionally, a notional MVDC ship power system is developed in the same environment to provide a test system with various distributed sources and loads. A load profile is developed for the main system components such as propulsion, service loads, and the advanced weaponry to reflect a notional battle scenario. The algorithm is first tested in simulation, and then deployed to external distributed controllers to validate the performance of the power management scheme under hardware constraints and communication latency. The algorithm is also demonstrated in conjunction with a management layer for distributed energy storage modules throughout the ship system to further illustrate the real-world viability of the method.
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Date Issued: 2018
Identifier: 2018_Su_Perkins_fsu_0071E_14716
Format: Thesis

Title: Distributed Energy Management Utilizing Model Predictive Control for Naval Ship Applications.
Creator: Gonsoulin, David E., Clark, Jonathan E., Faruque, Md Omar, Pamidi, Sastry V., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: Future Naval vessels are looking to incorporate a new variety of electrical loads. These loads include rail guns, high power radars, electric propulsion drives, and lasers. These loads, especially the rail gun, can be classified as high-power ramp rate loads. Before now, these types of loads were not prevalent on naval vessels; therefore, generators were used throughout the ship to power a multitude of devices that did not require high-power ramp rates. Many of the generators had a specific...
Show moreFuture Naval vessels are looking to incorporate a new variety of electrical loads. These loads include rail guns, high power radars, electric propulsion drives, and lasers. These loads, especially the rail gun, can be classified as high-power ramp rate loads. Before now, these types of loads were not prevalent on naval vessels; therefore, generators were used throughout the ship to power a multitude of devices that did not require high-power ramp rates. Many of the generators had a specific purpose; there were no interconnections between generators. With these new types of loads, a power system that can accommodate these devices is needed. Integrated Power Systems (IPS) look to solve the high-power ramp rate issue as well as provide a multitude of benefits such as efficiency, resiliency, and reconfigurability. The generators, loads, energy storages, protections, etc. will all be located and connected within the IPS. The IPS can provide the foundation to achieve a multitude of benefits; however, the control system must be intelligent in order to realize the IPS’ full potential. Part of the control problem is how to manage sources and loads to ensure load demand is met. In terrestrial systems, the near infinite bus takes care of changes in load demand. In a microgrid, such as those found on ships, a large change in load demand, such as those seen by high-power ramp rate loads, can have adverse effects on the power system and devices connected to the power system. The control must coordinate the sources and/or loads to ensure load demand is met with minimal impact to the system. In this dissertation, the beginnings of a distributed Energy Management control layer are shown. The control layer looks to assist in realizing the IPS’ full potential. This is done by providing a distributed type of control to fortify the resiliency and reliability, ensuring load demand is met, and certifying the energy storages state of charge is maintained to ensure an ever-ready presence. This control layer aims to meet load demand, ensure device constraints (power ratings, ramp rate limitations, etc.) are not exceeded, and maintain the energy storages desired state of charge. The control objective is met through a combined approach of a distributed spinning reserve algorithm and distributed MPC. The distributed MPC utilizes the distributed optimization technique called the Alternating Direction Method of Multipliers (ADMM).
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Date Issued: 2018
Identifier: 2018_Su_Gonsoulin_fsu_0071E_14741
Format: Thesis

Title: Design and Implementing Multipurpose Sensor Network for Smart City Monitoring.
Creator: Cai, Donglin, Arghandeh, Reza, Pamidi, Sastry V., Foo, Simon Y., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: Weather and Air quality monitoring are very important aspects of smart city management. As population increase in the cities, the emission of pollutants includes Carbone Monoxide, Nitrogen Dioxide, Ozone and the Particulate matter will increase which will cause health and environmental issue. This paper is about developing a low-cost Urban sensors box based on Internet of Things. The Urban box is equipped with 4G/3G wireless communication which allows the wide range of mobility around the...
Show moreWeather and Air quality monitoring are very important aspects of smart city management. As population increase in the cities, the emission of pollutants includes Carbone Monoxide, Nitrogen Dioxide, Ozone and the Particulate matter will increase which will cause health and environmental issue. This paper is about developing a low-cost Urban sensors box based on Internet of Things. The Urban box is equipped with 4G/3G wireless communication which allows the wide range of mobility around the city. The Urban Sensor box is a collaborative work to monitor real-time data of the city’s environment, infrastructure, and activities. All these data will be provided to understand the interconnected behavior of different tangible networks of the urban environment.
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Date Issued: 2018
Identifier: 2018_Su_CAI_fsu_0071N_14789
Format: Thesis

Title: Sensor Fault Detection and Isolation in Power Systems.
Creator: Yang, Huawei, Edrington, Christopher S., Ordóñez, Juan Carlos, Moss, Pedro L., Foo, Simon Y., Florida State University, College of Engineering, Department of Electrical and...
Show moreYang, Huawei, Edrington, Christopher S., Ordóñez, Juan Carlos, Moss, Pedro L., Foo, Simon Y., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: In large-scale power systems, the integration of intelligent monitoring system increases the system resiliency and the control robustness. For example, sensor monitoring allows to automatically supervise the health of sensors and detect sensor failures without relying on hardware redundancy, and hence, it will further reduce the cost of monitoring systems in power systems. Sensor failure is critical in smart grids, where controllers rely on healthy measurements from different sensors to...
Show moreIn large-scale power systems, the integration of intelligent monitoring system increases the system resiliency and the control robustness. For example, sensor monitoring allows to automatically supervise the health of sensors and detect sensor failures without relying on hardware redundancy, and hence, it will further reduce the cost of monitoring systems in power systems. Sensor failure is critical in smart grids, where controllers rely on healthy measurements from different sensors to determine all kinds of operations. Current literature review shows that most of the researchers focus on control and management side of smart grids, assuming the information control centers or agencies get from sensors is accurate. However, when sensor failure happens, missing data and/or bad data can flow into control and management systems, which may lead to potential malfunction or even power system failures. This brings the need for Sensor Fault Detection and Isolation (SFDI), to eliminate this potential threat. The integration of the SFDI into monitoring systems will allow avoiding the contingencies due to fault data, and therefore increases the system resiliency and the control robustness. Hardware redundancy is the common solution for SFDI. By placing multiple sensors in the same position, the control center can then rely on redundant sensors when one is broken or inaccurate. Apparently, this method will increase the cost significantly when applying to large power systems. Analytical redundancy, on the contrary, a quantitative method built from power system models, is a more promising solution. It does not necessarily require hardware redundancy and hence can lower the cost. With an appropriate number of sensors placed in strategic locations, the algorithm can then automatically detect sensor failures without the need of extra redundant sensors. Furthermore, SFDI together with intelligent sensor optimization and placement will also facilitate the transfer of conventional central grid control to distributed decision making agencies with minimum computation and communication burden for each branch, and thus, it will enhance the system performance and resiliency. In this dissertation, a comprehensive review over the state-of-the-art FDI methodologies is given at first, then a proposed algorithm to determine the optimal location of computation agents is introduced, which serves as a guide for the SFDI algorithm implementation explained right after. The results of the algorithms indicated promising application in power system monitoring.
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Date Issued: 2018
Identifier: 2018_Su_Yang_fsu_0071E_14730
Format: Thesis

Title: Control of Legged Robotic Systems: Substantiation of Gait Design, Multi-Modal Behaviors, and Dynamic Scaling Theory in Practice.
Creator: Blackman, Daniel J., Clark, Jonathan E., Oates, William, Moore, Carl A., Florida State University, College of Engineering, Department of Mechanical Engineering
Abstract/Description: Through limb structure and neuromuscular control, animals have demonstrated the ability to navigate obstacles and uneven terrain using a variety of different mechanisms and behaviors. Learning from the capabilities of animals, it is possible to develop robotic platforms that can aid in the study of these motions towards the production of new technologies for military, search and rescue, and medical applications. To produce these systems, it is important to first understand the underlying...
Show moreThrough limb structure and neuromuscular control, animals have demonstrated the ability to navigate obstacles and uneven terrain using a variety of different mechanisms and behaviors. Learning from the capabilities of animals, it is possible to develop robotic platforms that can aid in the study of these motions towards the production of new technologies for military, search and rescue, and medical applications. To produce these systems, it is important to first understand the underlying dynamics and design principles existent in nature that afford creatures such dexterous and agile movements. The creation of robots with legs provide a means for studying different aspects of the dynamics of legged locomotion. This includes investigations of limb coordination for gait controller design, the role of passive compliance in dynamic running, mechanical leg design and configuration for optimal energetic output, and scalability of legged systems in both simulation and through experimentation. This thesis aims to provide insight into the design and implementation of terrestrial robotic platforms with legs.
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Date Issued: 2018
Identifier: 2018_Su_Blackman_fsu_0071N_14797
Format: Thesis

Title: Intelligent Energy and Operation Management of AC, DC and Hybrid Microgrids Based on Evolutionary Techniques.
Creator: Papari, Behnaz, Edrington, Christopher S., Clark, Jonathan E., Pamidi, Sastry V., Moss, Pedro L., Florida State University, College of Engineering, Department of Electrical and...
Show morePapari, Behnaz, Edrington, Christopher S., Clark, Jonathan E., Pamidi, Sastry V., Moss, Pedro L., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Intelligent energy management systems (EMSs) play pivotal roles for microgrids (MGs). The integration of distributed generators (DGs), energy storage devices (ESDs), electrical vehicles (EVs), and flexible loads in a large-scale system of interconnected MGs needs a local management and control platforms to avoid probable integration issues. Most of the small scale aforementioned components are operated in low voltage (LV) power networks which require optimal strategies to achieve sufficient...
Show moreIntelligent energy management systems (EMSs) play pivotal roles for microgrids (MGs). The integration of distributed generators (DGs), energy storage devices (ESDs), electrical vehicles (EVs), and flexible loads in a large-scale system of interconnected MGs needs a local management and control platforms to avoid probable integration issues. Most of the small scale aforementioned components are operated in low voltage (LV) power networks which require optimal strategies to achieve sufficient performance to operate interconnected to other MGs and upstream networks. Thus, an active energy management strategy is required for off and on grid modes of terrestrial and shipboard MGs to satisfy all demands and minimize unwanted outcomes. Due to the high penetration of renewable energy sources (RESs) and their output fluctuations in MGs, stochastic analysis besides deterministic should be considered to reduce the uncertainty effects of RESs based on their probabilistic nature. Robust EMSs are needed to diminish prediction errors and improve the reliability of power supplies in hybrid and interconnected MGs. Nevertheless, qualified approach to fulfill EMS for LV MGs in the large-scale will be challenging in both grid operation modes. Optimization modules into tertiary management layer have considered as a potential solution in order to actualize control strategy of the terrestrial or ship MGs with different types of practical constraints. However, each of these methods not only yield benefits but also bring new challenges related to their shortage. Different approaches have been considered to fulfill the EMS requirements of MGs. A large amount of literature focuses on the management strategy of MG in an off-line manner rather than multiple MGs which interact with each other and an upstream network in an on-line manner. In addition, the most commonly used optimization modules in EMSs do not meet the computational burden and convergence capability trade-off required for real-time applications. This report proposes a heuristic optimization approach for distributed control and management of hybrid MGs for real-time requirements. The Crow Search Algorithm (CSA) offers a superior method to move traditional non-linear optimization approaches since its fewer control parameters permit a rapid response compared to other search approaches. Moreover, a distributed fashion CSA (DCSA) is implemented to fulfill linear and non-linear solver requirements of real-time EMSs for hybrid power distribution system.
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Date Issued: 2018
Identifier: 2018_Sp_Papari_fsu_0071E_14436
Format: Thesis

Title: Combined Electrical and Thermal Models for Integrated Cryogenic Systems of Multiple Superconducting Power Devices.
Creator: Satyanarayana, Sharath R. (Sharath Raghav), Pamidi, Sastry V., Foo, Simon Y., Bernadin, Shonda, Florida State University, College of Engineering, Department of Electrical and...
Show moreSatyanarayana, Sharath R. (Sharath Raghav), Pamidi, Sastry V., Foo, Simon Y., Bernadin, Shonda, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: High Temperature Superconducting (HTS) technology is a potential option for applications that require high power densities for lightweight and compact solutions for transportation systems such as electric aircrafts and all-electric Navy ships. Several individual HTS power devices have been successfully demonstrated for these systems. However, the real benefit lies in providing the system level design flexibility and operational advantages with an integrated cryogenic system. A centralized...
Show moreHigh Temperature Superconducting (HTS) technology is a potential option for applications that require high power densities for lightweight and compact solutions for transportation systems such as electric aircrafts and all-electric Navy ships. Several individual HTS power devices have been successfully demonstrated for these systems. However, the real benefit lies in providing the system level design flexibility and operational advantages with an integrated cryogenic system. A centralized cryogenic cooling technology is being explored to serve multiple HTS devices in a closed loop system. This provides high efficiency and permits directing the cooling power to where it is needed depending on the mission at hand which provides operational flexibility. Design optimization, risk mitigation and the operational characteristics under various conditions need to be studied to increase the confidence level in HTS technology. Development of simpler and cost-efficient cryogenic systems are essential to make HTS systems attractive. Detailed electrical and cryogenic thermal models of the devices are also necessary to understand the of risks in HTS power systems and to devise mitigation techniques for all the potential failure modes. As the thermal and electrical characteristics of HTS devices are intertwined, coupled thermal and electrical models are necessary to perform system level studies. To enable versatile and fast models, the thermal network method is introduced for cryogenic systems. The effectiveness of the modelling technology was demonstrated using case studies of multiple HTS devices in a closed loop cryogenic helium circulation system connected in different configurations to access the relative merits of each configuration. Studies of transient behavior of HTS systems are also important to understand the response of a large HTS system after one of the cryogenic cooling components fails. These studies are essential to understand the risks and potential options in the design or in operations to mitigate some of the risks. Thermal network models developed in this study are also useful to study the temperature evolution along the whole system as a function of time after a component fails. The models are useful in exploring the design options to extend the time of operation of a device such as a HTS cable after the failure of the cryogenic system.
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Date Issued: 2018
Identifier: 2018_Su_Satyanarayana_fsu_0071N_14787
Format: Thesis

Title: Experimental Characterization and Uncertainty Quantification of High Temperature Pressure Sensing Materials.
Creator: Consoliver-Zack, Jakob, Oates, William, Hellstrom, Eric, Kumar, Rajan, Florida State University, College of Engineering, Department of Mechanical Engineering
Abstract/Description: Sapphire is presently being utilized in optical based pressure traducers for use in measuring pressure at high temperatures. The robustness of sapphire makes it an ideal material for use as a high temperature sensor; however, not without its own challenges. Sapphire cannot be machined using conventional methods so alternatives such as laser machining us- ing a picosecond laser have been investigated. This method has shown to cause significant changes to the material including modulus,...
Show moreSapphire is presently being utilized in optical based pressure traducers for use in measuring pressure at high temperatures. The robustness of sapphire makes it an ideal material for use as a high temperature sensor; however, not without its own challenges. Sapphire cannot be machined using conventional methods so alternatives such as laser machining us- ing a picosecond laser have been investigated. This method has shown to cause significant changes to the material including modulus, strength, and toughness. The specific cause of these changes is hypothesized to be due to residual stress induced in the crystal lattice. This was investigated using x-ray diffraction coupled with Bayesian uncertainty techniques. The computed tensor showed in-plane compressive stresses which would result in increased strength. Due to the challenges of machining sapphire, an alternative material called Maxthal 211 (Ti2AlC) was also investigated. The mechanical response under cyclic loading both pre and post annealing was examined using a uniaxial wafer bending setup. Hysteretic losses were shown to drop significantly on the second cycle, regardless of the annealing treatment.
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Date Issued: 2018
Identifier: 2018_Su_ConsoliverZack_fsu_0071N_14620
Format: Thesis

Title: Active Control of Salient Flow Features in the Wake of a Ground Vehicle.
Creator: McNally, Jonathan William, Alvi, Farrukh S., Jung, Sungmoon, Kumar, Rajan, Taira, Kunihiko, Hahn, Seung Yong, Florida State University, College of Engineering, Department of...
Show moreMcNally, Jonathan William, Alvi, Farrukh S., Jung, Sungmoon, Kumar, Rajan, Taira, Kunihiko, Hahn, Seung Yong, Florida State University, College of Engineering, Department of Mechanical Engineering
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Abstract/Description: Aerodynamics of road vehicles have continued to be a topic of interest due the relationship between fuel efficiency and the environmental impact of passenger vehicles. With the streamlining of ground vehicles combined with years of geometric and shape optimization, other techniques are required to continue to improve upon fuel consumption. One such technique leverages aerodynamics to minimize drag through the implementation of flow control techniques. The current study focuses on the...
Show moreAerodynamics of road vehicles have continued to be a topic of interest due the relationship between fuel efficiency and the environmental impact of passenger vehicles. With the streamlining of ground vehicles combined with years of geometric and shape optimization, other techniques are required to continue to improve upon fuel consumption. One such technique leverages aerodynamics to minimize drag through the implementation of flow control techniques. The current study focuses on the application of active flow control in ground vehicle applications, employing linear arrays of discrete microjets on the rear of a 25 Ahmed model. The locations of the arrays are selected to test the effectiveness of microjet control at directly manipulating the various features found in typical flow fields generated by ground vehicles. Parametric sweeps are conducted to investigate the flow response as a function of jet velocity, momentum, and vehicle scaling. The effect and effciency of the control are quantified through aerodynamic force measurements, while local modifications are investigated via particle image velocimetry and static pressure measurements on the rear surfaces of the model. Microjets proved most effective when utilized for separation control producing a maximum change to the coefficients of drag and lift of -14.0% and -42% of the baseline values, respectively. Control techniques targeting other flow structures such as the C-pillar vortices and trailing wake proved less effective, producing a maximum reduction in drag and lift of -1.2% and -7%. The change in the surface pressure distribution reveals the impact of each flow control strategy on a targeted flow structure, and highlights the complex interaction between the salient flow features found in the wake of the Ahmed model. Areas of pressure recovery on the surface of the model observed for each control technique support the observed changes to the aerodynamic forces. The time averaged, volumetric wake is also reconstructed to characterize the baseline flow field and highlight the effect of control on the three dimensional structure of the near wake region. The results show that separation control has a measurable effect on the flow field including modifications of the locations, size, magnitude, and trajectory of the various structures which comprise the near wake. The observations give insight into desirable modifications and flow topology which lead to an optimal drag configuration for a particular vehicle geometry.
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Date Issued: 2018
Identifier: 2018_Su_McNally_fsu_0071E_14507
Format: Thesis

Title: Use of Resolvent Analysis for Design of Active Separation Control with Thermal-Based Actuators.
Creator: Yeh, Chi-An, Taira, Kunihiko, Tam, Christopher K. W., Cattafesta, Louis N., Alvi, Farrukh S., Oates, William, Florida State University, College of Engineering, Department of...
Show moreYeh, Chi-An, Taira, Kunihiko, Tam, Christopher K. W., Cattafesta, Louis N., Alvi, Farrukh S., Oates, William, Florida State University, College of Engineering, Department of Mechanical Engineering
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Abstract/Description: This study aims to examine the use of a fundamental thermal input for separation control and provide a design guideline via resolvent analysis. The use of the thermal actuator is motivated by the interest in the use of thermal-energy-based actuators from the active flow control community. We conduct a series of numerical investigations to uncover the underlying control mechanism of thermal-energy-based actuators and examine their control effectiveness when a fundamental thermal energy source...
Show moreThis study aims to examine the use of a fundamental thermal input for separation control and provide a design guideline via resolvent analysis. The use of the thermal actuator is motivated by the interest in the use of thermal-energy-based actuators from the active flow control community. We conduct a series of numerical investigations to uncover the underlying control mechanism of thermal-energy-based actuators and examine their control effectiveness when a fundamental thermal energy source is introduced as the only external perturbation. We consider a thermal actuator model that introduces localized boundary actuation in the form of unsteady heat flux. This external thermal actuation is added to the right-hand-side of the energy equation in the compressible Navier--Stokes equations. We study how the localized thermal forcing affects the far-field and near-field of the surrounding flow. To provide design guidelines to active separation control, we perform resolvent analysis on the mean baseline flows and use it as a linear model to examine the energy amplification and flow response to different actuation frequencies and wavenumbers. Since the key to suppressing flow separation lies in the excitation of the instabilities in the shear layer that forms over the airfoil, we consider a free shear layer and perturb it with a fundamental thermal input in the first part of this study. In this model problem, local periodic heating is introduced at the trailing edge of a finite-thickness splitter plate. Two-dimensional direct numerical simulations are performed at the plate-thickness-based Reynolds number of 1000. We find that thermal actuation introduces low level of oscillatory surface vorticity flux and baroclinic torque at the actuation frequency in the vicinity of the trailing edge. The produced vortical perturbations can independently excite the fundamental instability that accounts for shear layer roll-up as well as the subharmonic instability that encourages the vortex pairing process farther downstream. We demonstrate that the nonlinear dynamics of a spatially developing shear layer can be modified by the local oscillatory heat flux as a control input. Next, we leverage the findings from the thermally perturbed free shear layer and extend the employment of the thermal actuation technique to the control of flow separation over an airfoil. The separated flows over a NACA 0012 airfoil at two post-stall angles of attack 6° and 9° and chord-based Reynolds number ReLc = 23,000 are considered. The thermal actuator is placed near the leading edge to introduce unsteady thermal forcing. Three-dimensional large-eddy simulations (LES) are employed in this investigation. Of particular interest is the influence of the frequency and spanwise wavelength of the thermal actuator introduced at the natural separation point. We observe that the thermal forcing is capable of reattaching the flow by encouraging the roll-up of the vortex sheet emanating from the leading edge. Discrete coherent spanwise vortices are formed and leads to the generation of low-pressure region over the top surface enabling lift enhancement. Under certain 2D actuation cases, the turbulent flow is completely laminarized and turns into a 2D flow. To further enhance the aerodynamic performance of the wing, we consider the trigger of vortex breakdown by introducing spanwise perturbation in the thermal forcing. It is found that spanwise variation in the forcing can enhance mixing past the mid chord and entrains free-stream momentum, benefitting from both the low-pressure core of the spanwise vortices and the recovery of the flow momentum in the aft portion of the wing. For the successful controlled case that achieves reattachment, we observe a significant reduction in drag by up to 49% and an increase in lift by up to 54%. The fluctuations in aerodynamic forces are also reduced by up to 84% with the unsteady thermal actuation. We also find that the excitation of shear-layer roll-up over the airfoil and the turbulent-laminar transition after the roll-up both play important roles to achieve effective separation control. Complementary to the parametric study using LES, we perform resolvent analysis on the baseline flows to obtain further physics-based guidance for the effective choice of these control input parameters. The global resolvent analysis is conducted on the baseline turbulent mean flows to identify the actuation frequency and wavenumber that provide high energy amplification. The present analysis also considers the use of a temporal filter to limit the time horizon for assessing the energy amplification to extend resolvent analysis to unstable base flows. We incorporate the amplification and response mode from resolvent analysis to provide a metric that quantifies momentum mixing associated with the modal structure. By comparing this metric from resolvent analysis and the LES results of controlled flows, we demonstrate that resolvent analysis can predict the effective range of actuation frequency as well as the global response to the actuation input. We demonstrated the effectiveness of the thermal actuation to suppress flow separation over the airfoil. Supported by the agreements between the results from resolvent analysis and LES, we believe that this study provides insights for the use of resolvent analysis in guiding future active flow control.
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Date Issued: 2018
Identifier: 2018_Su_Yeh_fsu_0071E_14631
Format: Thesis

Title: Application and Analysis of the Extended Lawrence Teleoperation Architecture to Power Hardware-in-the-Loop Simulation.
Creator: Langston, James, Edrington, Christopher S., Vanli, Omer Arda, Steurer, Michael, Roberts, Rodney G., Faruque, Md Omar, Florida State University, College of Engineering,...
Show moreLangston, James, Edrington, Christopher S., Vanli, Omer Arda, Steurer, Michael, Roberts, Rodney G., Faruque, Md Omar, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Power hardware-in-the-loop (PHIL) simulation is a technique whereby actual power hardware is interfaced to a virtual surrounding system through PHIL interfaces making use of power amplifiers and/or actuators. PHIL simulation is often an attractive approach for early integration testing of devices, allowing testing with unrealized systems with substantial flexibility. However, while PHIL simulation offers a number of potential benefits, there are also a number of associated challenges and...
Show morePower hardware-in-the-loop (PHIL) simulation is a technique whereby actual power hardware is interfaced to a virtual surrounding system through PHIL interfaces making use of power amplifiers and/or actuators. PHIL simulation is often an attractive approach for early integration testing of devices, allowing testing with unrealized systems with substantial flexibility. However, while PHIL simulation offers a number of potential benefits, there are also a number of associated challenges and limitations stemming from the non-ideal aspects of the PHIL interface. These can affect the accuracy of the experiments and, in some cases, lead to instabilities. Consequently, accuracy, stability, and sensitivity to disturbances are some of the most important considerations in the analysis and design of PHIL simulation experiments, and the development of PHIL interface algorithms (IA) and augmentations for improvements in these areas is the subject of active research. Another area of research sharing some common attributes with PHIL simulation is the field of robotic bilateral teleoperation systems. While there are some distinctions and differences in characteristics between the two fields, much of the literature is also focused on the development of algorithms and techniques for coupling objects. A number of disparate algorithms and augmentations have also been proposed in the teleoperation literature, some of which are fundamentally very similar to those applied in PHIL simulation. While some of the teleoperation methods may have limited applicability in PHIL experiments, others have substantial relevance and may lend themselves to improvements in the PHIL application area. This work focuses on the application and analysis of a teleoperation framework in the context of PHIL simulation. The extended Lawrence Architecture (ELA) is a framework unifying and describing a large set of teleoperation interfacing algorithms. This work focuses on the application and analysis of the ELA to PHIL simulation. This includes the expression of existing PHIL IAs in the context of the ELA, derivation of relevant transfer functions and metrics for assessment of performance, the exploration of the implications of the transparency requirements, and the exploration of new IAs supported by the ELA which may be well suited to the particular characteristics of PHIL simulation.
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Date Issued: 2018
Identifier: 2018_Sp_Langston_fsu_0071E_14321
Format: Thesis

Title: Auxetic and Hybrid Structure Designs and Advanced Manufacturing Study for Energy Absorption Improvements.
Creator: Ingrole, Aniket Arvind, Liang, Zhiyong, Jung, Sungmoon, Zeng, Changchun, Dickens, Tarik, Florida State University, College of Engineering, Department of Industrial and...
Show moreIngrole, Aniket Arvind, Liang, Zhiyong, Jung, Sungmoon, Zeng, Changchun, Dickens, Tarik, Florida State University, College of Engineering, Department of Industrial and Manufacturing Engineering
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Abstract/Description: One of the major concerns for many athletes in todays' sports is mild Traumatic Brain Injury (mTBI), which is commonly known as concussion. Researchers and manufacturers of sport helmets are constantly trying to develop new designs and technologies to better prevent mTBI. The objective of this research is to study the effective designs for sport helmets that can potentially absorb and dispel both linear and rotational forces acting on the head during impact. Inspiration by the different types...
Show moreOne of the major concerns for many athletes in todays' sports is mild Traumatic Brain Injury (mTBI), which is commonly known as concussion. Researchers and manufacturers of sport helmets are constantly trying to develop new designs and technologies to better prevent mTBI. The objective of this research is to study the effective designs for sport helmets that can potentially absorb and dispel both linear and rotational forces acting on the head during impact. Inspiration by the different types of working mechanisms and structures existing in nature that can absorb energy from different types of impacts, new designs were explored. Honeycomb structures have been used extensively in lightweight sandwich structure and impact energy absorption applications. Recently, Auxetic structures are attractive for various engineering applications because of their unique mechanical properties, volume change control and excellent impact energy absorption performance. In this study, novel designs and performance improvement of new auxetic-strut structures were presented. A comparative study of in-plane and out-of-plane uniaxial compression loading behavior of regular honeycomb, re-entrant auxetic honeycomb, locally reinforced auxetic-strut structure and a hybrid structure of combining regular honeycomb and auxetic-strut structure was conducted. Finite element modelling was carried out to reveal their structure-property relationships. The deformation and failure modes of the different designs were studied and their performance was also discussed. The new auxetic-strut structure showed better mechanical properties than the honeycomb and auxetic structures with a small density increase. For in-plane performance, the compressive strength of the auxetic-strut design is ~300% more than that of honeycomb structure and ~65% more than that of auxetic structure. With lower values of the Poisson’s ratio, the new design can absorb more energy when compared to the other structures. The out-of-plane properties of auxetic-strut design showed an increase of ~68% in the compressive strength, ~63% in Young’s modulus and ~32% in the total energy absorbed when compared with the honeycomb structure. The hybrid structures also showed excellent out-of-plane properties. With better in-plane and out-of-plane properties, auxetic-strut design can be used in various energy absorption applications. Hybrid designs allow us to tailor properties of the structures with their specific in-plane and out-of-plane deformation and failure modes A comparative study of dynamic crushing behavior of the structures was also carried out. Finite element modelling was conducted to compare the dynamic crushing behavior of these structures at different impact velocities. Deformation mechanisms of these structures were studied, that provided the new insights on how to control the deformation of the structure and tailor the properties. For in-plane impact tests the energy absorbed by auxetic- strut and hybrid structures was half when compared with honeycomb and re-entrant auxetic structures at lower strain levels. But at higher strain levels, the new structures performed twice as that of the later. In contrary for out-of-plane crushing, the energy absorbed by the auxetic-strut and hybrid structures was higher than the honeycomb and re-entrant auxetic structures at lower strain levels and vice-versa. Advanced manufacturing or 3D printing method were employed to produce samples of the new designs. The results of the sample tests are in good agreement with the modeling predictions. These results are valuable to provide new fundamental understanding of structure-property relationships for new auxetic-strut and their hybrid honeycomb structures for potential aerospace and sporting product applications, especially in football helmets.
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Date Issued: 2018
Identifier: 2018_Sp_Ingrole_fsu_0071E_14338
Format: Thesis

Title: Performance Limits of Powder in Tube Processed Nb₃Sn Superconducting Wires.
Creator: Segal, Christopher B., Larbalestier, D., Kametani, Fumitake, Collins, E., Tarantini, C., Lee, Peter J., Florida State University, College of Engineering, Department of...
Show moreSegal, Christopher B., Larbalestier, D., Kametani, Fumitake, Collins, E., Tarantini, C., Lee, Peter J., Florida State University, College of Engineering, Department of Mechanical Engineering
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Abstract/Description: For 10-15 years, the Powder-In-Tube (PIT) process has been one of the leading manufacturing methods for producing the highest critical current density (Jc) Nb₃Sn wires for at small effective filament diameter (deff), both required for future applications in high energy physics. Since Nb₃Sn first became commercially available in the 1960's, non-Cu Jc values have steadily climbed until a plateau was reached at about 3,000~A/mm (12~T, 4.2~K) in the year 2000. Comprehensive analysis of recent...
Show moreFor 10-15 years, the Powder-In-Tube (PIT) process has been one of the leading manufacturing methods for producing the highest critical current density (Jc) Nb₃Sn wires for at small effective filament diameter (deff), both required for future applications in high energy physics. Since Nb₃Sn first became commercially available in the 1960's, non-Cu Jc values have steadily climbed until a plateau was reached at about 3,000~A/mm (12~T, 4.2~K) in the year 2000. Comprehensive analysis of recent wires suggests that both PIT and the other high Jc wire design, Rod Restack Process (RRP), have yet to achieve their maximum potential as high Jc conductors. Currently, PIT wires obtain a maximum Jc(12~T, 4.2~K) of about 2700~A/mm2 and do so by converting up to 60% of the non-Cu cross section into superconducting Nb₃Sn. However, about a quarter of this volume fraction is made of large grains of Nb₃Sn which are too large or otherwise disconnected to carry current in transport, wasting both real estate, as well as Sn and Nb that would be better used to make the desired small grain A15. The most recent RRP wires typically achieve Jc values of around 3000~A/mm2 by also converting about 60% of the non-Cu cross section into A15, however nearly all of that has the desired small grain morphology with high vortex pinning, ideal for current transport. Studies at the Applied Superconductivity Center have shown that one route to improvement for both wires may be in controlling the formation of intermediate phases which form before Nb₃Sn . An intermetallic Nb-Cu-Sn, commonly referred to as Nausite, is considered responsible for the formation of the undesirable large grains. We studied the phase evolution in PIT Nb₃Sn from the starting powder mixture at room temperature up to 690°C to better understand what role Nausite ((Nb0.75Cu0.25)Sn₂) actually plays in forming large grain A15 with the goal of preventing its formation and making better use of the Sn available to form the desired small grain A15 morphology. After heat treatment, all wires were imaged in an SEM and then processed through digital image analysis software, extracting area fractions of each phase and their morphology. For heat treatments which showed interesting metallographic results, additional measurements were made by transport, resistivity, magnetization, and/or heat capacity to develop a complete picture of how the microstructure affects critical wire properties. Based on these results, novel heat treatments were developed and demonstrated our ability to reduce the undesired large grain A15 while simultaneously producing more current-carrying small grain A15, increasing the ratio of small:large grain A15 from 3.0 to 3.8. Another possible path to improvement is to reduce the non-uniform deformation incurred during wire fabrication. A PIT Nb₃Sn wire begins as a mono-filament consisting of a thick Nb7.5wt%Ta tube clad in high-purity Cu, inscribed with a Cu sleeve, and filled with a Sn-rich NbSn₂ powder. The external Cu cladding will later provide a low resistance normal conducting path around superconducting filaments, a necessity for magnet stability. The final wire diameter is between 0.7-1.25~mm with 156 or 192 filaments, whose diameters are 33-50~μm, organized into 6-7 concentric rings. Through advanced digital image analysis software, we can extract geometric information which describes how the wire and filaments deform from their nominally circular shape, becoming elliptical or otherwise having non-uniform deformation which can be detrimental to wire properties. We found that the non-uniform deformation incurred during wire fabrication can degrade the wire performance. The most severe effect is caused by the different deformation rates of the Nb-Ta tube compared to its powder core, which leads to the Sn-rich core drifting from the center of the Nb-Ta tube, leading to an uneven A15 reaction front. This is referred to here as 'centroid drift'. In PIT wires, the diffusion barrier must be consumed to form A15 while still leaving a thin, protective annulus behind to protect the Cu. Centroid drift then causes a large inefficiency as it creates a thick and thin side of diffusion barrier, the thin side limiting the reaction if Sn leaks are to be prevented, while the thick side becomes wasted Nb-Ta. Up to 30% of the final non-Cu cross-section remains as unused diffusion barrier. When Sn leaks out of the filaments it increases the resistivity of the Cu stabilizer, lowering the Residual Resistance Ratio (RRR). A high RRR is required for magnet stability, and such Sn leaks can be detrimental to magnet performance. In addition, we found that filaments farther from the center of the wire tend to be those with highest centroid drift, and they are also the most susceptible to leaking Sn. Moreover, we observed that in leaks severe enough to produce a Kirkendall void, the A15 volume is also reduced. By comparison, RRP type wires manage a similar reaction with less than 10% residual barrier in the non-Cu cross section. Recently, Bruker EAS, the manufacturer of PIT Nb₃Sn wires, developed a new wire design which added a bundle barrier around the filament pack to contain Sn leaks and maintain a high RRR, as well as increasing the Sn content in the powder core to produce more A15. We believe that by improving deformation properties and optimizing new heat treatments to account for the higher Sn content, Jc can be substantially enhanced while maintaining RRR at small filament diameters.
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Date Issued: 2018
Identifier: 2018_Sp_Segal_fsu_0071E_14456
Format: Thesis

Title: Thrust Measurements on a Rocket Nozzle Using Flow-Field Diagnostics.
Creator: Vemula, Rohit Chandra, Kumar, Rajan, Oates, William, Yaghoobian, Neda, Florida State University, College of Engineering, Department of Mechanical Engineering
Abstract/Description: With an increase in the number of space transport applications, the need for larger, more powerful and efficient rocket motors are the need of the day. Thus, optimizing the thrust generated by these rocket motors is of great importance, which can be achieved by bell-shaped nozzles with high area ratios. However, the high area ratios result in significant over-expansion at sea level conditions, that cause flow separation inside the nozzle and generate side-loads. Several novel nozzle designs...
Show moreWith an increase in the number of space transport applications, the need for larger, more powerful and efficient rocket motors are the need of the day. Thus, optimizing the thrust generated by these rocket motors is of great importance, which can be achieved by bell-shaped nozzles with high area ratios. However, the high area ratios result in significant over-expansion at sea level conditions, that cause flow separation inside the nozzle and generate side-loads. Several novel nozzle designs are being developed to overcome the flow separation phenomenon. Characterizing the thrust output from these nozzles in a laboratory is vital for their successful development and implementation. Conventionally, the thrust from a nozzle is measured using load cells on a thrust stand. A thrust stand can provide limited information on the loads generated by the flow through a nozzle, such as the magnitude and direction of time average loads, but the flow features responsible for generating them remain elusive. In the present study, a novel method to estimate thrust from flow-field data, obtained by Particle Image Velocimetry (PIV) experiments and Pitot pressure survey at the nozzle exit, is proposed. The thrust estimated by this method is then validated with the conventional thrust measurements using load cells. A Mach 4 convergent-divergent nozzle with 12.7 mm throat diameter was tested using compressed air at a range of substantially over-expanded operating conditions with Nozzle pressure ratio (NPR) of 4, 5, 6, 7 and 7.5, at two temperature ratios (TR =1.2 and TR =1.5). The flow field at the nozzle exit was surveyed at these conditions using a Pitot tube mounted on a 2-D traverse system and the stereo PIV technique. Using the data obtained from both the flow surveys in the rocket thrust equation, the values of thrust are estimated. The thrust estimated from the flow field data showed identical levels at both temperature ratios. This suggested that temperature ratio has a negligible impact on the thrust measured at respective NPR. Using a load cell, the thrust produced by the nozzle was measured for each NPR at isothermal condition (TR=1). A comparison between the thrust obtained by the two methods verified that PIV and pressure surveys could be used to determine the time-averaged thrust of a nozzle to within 6% of the load cell readings. This experimental study provides a reliable alternative method for rocket nozzle thrust measurements
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Date Issued: 2018
Identifier: 2018_Sp_Vemula_fsu_0071N_14314
Format: Thesis

Title: Melt Structure and Crystallization of Random Ethylene Copolymers.
Creator: Chen, Xuejian, Alamo, Rufina G., Shanbhag, Sachin, Hallinan, Daniel T., Chung, Hoyong, Florida State University, College of Engineering, Department of Chemical and Biomedical...
Show moreChen, Xuejian, Alamo, Rufina G., Shanbhag, Sachin, Hallinan, Daniel T., Chung, Hoyong, Florida State University, College of Engineering, Department of Chemical and Biomedical Engineering
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Abstract/Description: Linear low density polyethylenes (LLDPEs are substantially linear polyethylenes [(C2H4)n] with randomly distributed 1-alkyl short chain branches. The presence of branches on the ethylene backbone sharply reduces the crystallinity level of LLDPEs and retards the crystallization rate compared to the homopolymer. With respect the linear chain, LLDPEs are more flexible, ductile, and more transparent; hence, they are widely used for film applications. It is of great interest to find avenues to...
Show moreLinear low density polyethylenes (LLDPEs are substantially linear polyethylenes [(C2H4)n] with randomly distributed 1-alkyl short chain branches. The presence of branches on the ethylene backbone sharply reduces the crystallinity level of LLDPEs and retards the crystallization rate compared to the homopolymer. With respect the linear chain, LLDPEs are more flexible, ductile, and more transparent; hence, they are widely used for film applications. It is of great interest to find avenues to increase the crystallization rate of LLPDEs, or increase production cycles, due to its huge global demand. This work covers a comprehensive study of the correlation between melt topology and phase structure with the crystallization rates of LLDPEs. Narrowly distributed random ethylene 1-alkene copolymers display strong memory of crystallization in the melt, even at temperatures above their equilibrium melting point, as indicated by a sharp increase in the re-crystallization temperature. Melt-memory is associated with ethylene sequences from prior crystallites that remain in close proximity forming clusters that do not dissolve till very high temperatures. The melt memory strength first increases with branch content due to a topologically more complex inter-crystalline region formed by diffusing a larger number of crystalline sequences and then decreases due to depleted crystallinity level. The observed MM strength is independent of alkyl branch length up to octyl. Increasing the crystallinity level makes the inter-crystalline region topologically more complex, retarding the dissolution of the clusters in the melt. The dissolution process is thermally activated and becomes extremely slow in the melt of high molar mass copolymers (> 50 kDa) with ~2.2 mol% ethyl branches. Broadly distributed random ethylene 1-alkene copolymers, display a special melt memory effect: the crystallization rate increases and then decreases with lowering temperature the melt is cooled from. This inversion of the expected trend of the crystallization rate is associated with the onset of liquid-liquid phase separation (LLPS) between lowly branched molecules and highly branched molecules. Upon decreasing melt temperature and crossing the binodal, the thermodynamic drive of phase separation enhances chain dynamics and accelerates dissolution of melt memory. Strong evidence of LLPS is provided in both, solid and melt states using TEM, AFM, SANS, SALS and BF-OM. The inversion of crystallization rate is enhanced in systems with a broader distribution of branch content due to stronger thermodynamic drive of phase separation.
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Date Issued: 2018
Identifier: 2018_Sp_Chen_fsu_0071E_14395
Format: Thesis

Title: DTI-Based Network Analysis of Female APP/PS1 Mouse Brains.
Creator: Hike, David, Grant, Samuel C., Guan, Jingjiao, Li, Yan, Florida State University, College of Engineering, Department of Chemical and Biomedical Engineering
Abstract/Description: Diffusion tensor imaging (DTI) provides a map of diffusional anisotropy based on the Brownian motion of water within the restricted boundaries of tissues. In this work, a high angular resolution DTI acquired with 18 diffusion directions and four unweighted images was acquired using a 11.75-T, 500-MHz MRI scanner located at the FAMU-FSU College of Engineering in order to perform tractography in amyloid precursor protein/presenilin 1 (APP/PS1) mouse models of familial Alzheimer’s Disease....
Show moreDiffusion tensor imaging (DTI) provides a map of diffusional anisotropy based on the Brownian motion of water within the restricted boundaries of tissues. In this work, a high angular resolution DTI acquired with 18 diffusion directions and four unweighted images was acquired using a 11.75-T, 500-MHz MRI scanner located at the FAMU-FSU College of Engineering in order to perform tractography in amyloid precursor protein/presenilin 1 (APP/PS1) mouse models of familial Alzheimer’s Disease. Evaluating phenotype (APP/PS1 versus wild type) and age (1, 2, 4 and 6 months), a structural network analysis was employed to assess DTI datasets acquired at an in-plane resolution was 100 x 100 microns with a matrix size of 256 x 256, repetition time of 2 s, echo time of 30 ms, diffusion gradient separation of 21 ms and diffusion gradient time of 3 ms. With 15 averages, high signal-to-noise ratios were achieved over an approximate acquisition time of 47 h per sample. This study used all female brains fixed with 4% paraformaldehyde. The five main neural areas of focus were the piriform area of the cortex, temporal cortex, parietal cortex, and left and right hippocampus. A significant decrease in FA of the temporal cortex was identified. Changes in the network metrics of weighted degree, eccentricity, clustering, betweenness centrality, and closeness centrality were observed as a function of age and phenotype.
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Date Issued: 2018
Identifier: 2018_Sp_Hike_fsu_0071N_14573
Format: Thesis

Title: Architected Multiscale Polymer Foams.
Creator: Ahmed, Mohammad Faisal, Zeng, Changchun, Shanbhag, Sachin, Liang, Zhiyong, Yu, Zhibin, Florida State University, College of Engineering, Department of Industrial and...
Show moreAhmed, Mohammad Faisal, Zeng, Changchun, Shanbhag, Sachin, Liang, Zhiyong, Yu, Zhibin, Florida State University, College of Engineering, Department of Industrial and Manufacturing Engineering
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Abstract/Description: Polymeric foam materials continue to gather commercial and research interests due to their unique physical characteristics and emerging applications in a wide variety of industries. This research work viewed the polymer foam industry from three different perspectives, namely materials, processes and applications. Accordingly, technical challenges were carefully selected to make contributions towards each segment by expanding materials choice, proposing architected foam fabrication process and...
Show morePolymeric foam materials continue to gather commercial and research interests due to their unique physical characteristics and emerging applications in a wide variety of industries. This research work viewed the polymer foam industry from three different perspectives, namely materials, processes and applications. Accordingly, technical challenges were carefully selected to make contributions towards each segment by expanding materials choice, proposing architected foam fabrication process and exploring multifunctional applications of foam sensors. Thermoplastic elastomers are thermally processable yet rubberlike materials which experience shrinkage when operated between the glass transition temperatures of soft rubbery phase and hard phase. This brings a challenge in making microcellular foams using batch foaming process where the materials are not fully melted to generate cellular structure. The issue was addressed in this research by incorporating a second phase (i.e. a polymer blend system) to perform as a shape fixing unit. Thus, a series of thermoplastic polyurethane (TPU) elastomeric foams were prepared by blending polylactic acid (PLA) as the shape fixing unit. The morphological, thermal and rheological behavior of the blend system was studied prior to foaming. The blends that contained PLA as the minor phase resulted in foams with high expansion ratio. These blend foams were compared to TPU foams in terms of shape fixity ratio. The results were fitted with Kohlrausch-Williams-Watts (KWW) function to estimate foam relaxation times. Foam relaxation time and shape fixity ratio increased with increasing PLA content. The glass transition temperature of PLA performed as the anchor point to stabilize the foam structure. Architected polymeric materials when designed for specific application could satisfy design requirements with desired unit cell design for having controllable pore size, pore density and pore connectivity. With development of additive manufacturing, fabrication of macro, micro and even nano porous structures have become a possibility. In this research, a new route to fabricating architected multiscale polymer foam is proposed and consequently studied in detail with a view to realizing its potential as a near net-shape process. The fabrication process utilized the synergy of additive manufacturing and batch foaming process to induce macro and microporosity (i.e. structural hierarchy). The results suggested that the process can generate foams with more than 95% expansion uniformity with significantly reduced saturation time. The process is also capable of handling a variety of thermoplastics which also includes polymer blends. Traditional applications of polymeric materials include insulation, energy absorption, floatation, packaging and so on. Though a relatively new concept, multifunctional foams have attracted the research community to develop and explore applications of materials that utilize foams as the skeleton. Such materials demonstrate sensing capability for having piezoresistive characteristics induced by conductive nanomaterials. Piezoresistive auxetic foams sensors coated with silver nanowire were prepared in this research to demonstrate their application as pressure sensors, 3D strain sensors, smart filtration and human motion interface. The auxetic foam sensors reported herein demonstrated improved piezoresistive properties compared to conventional counterpart and showed repeatable and reliable sensing performance for a variety of deformation modes.
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Date Issued: 2018
Identifier: 2018_Su_Ahmed_fsu_0071E_14717
Format: Thesis

Title: Analysis of Non-Thermal Plasma Discharge Contacting Liquid Water Using Plasma Diagnostics and Computer Simulations.
Creator: Wang, Huihui, Locke, Bruce R., Alabugin, Igor V., Chella, Ravindran, Alamo, Rufina G., Florida State University, College of Engineering, Department of Chemical and Biomedical...
Show moreWang, Huihui, Locke, Bruce R., Alabugin, Igor V., Chella, Ravindran, Alamo, Rufina G., Florida State University, College of Engineering, Department of Chemical and Biomedical Engineering
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Abstract/Description: Non-thermal plasma technology, which can be used as an advanced oxidation process (AOP) for water treatment, has gained significant attention recently. A plasma discharge contacting liquid water generates strong oxidants, such as ·OH and H2O2 and, in the presence of O2, ozone (O3), which are capable of degrading or completely mineralizing many organic pollutants in waste water. The UV irradiation generated during the plasma discharge can enhance the degradation of organic compounds and kill...
Show moreNon-thermal plasma technology, which can be used as an advanced oxidation process (AOP) for water treatment, has gained significant attention recently. A plasma discharge contacting liquid water generates strong oxidants, such as ·OH and H2O2 and, in the presence of O2, ozone (O3), which are capable of degrading or completely mineralizing many organic pollutants in waste water. The UV irradiation generated during the plasma discharge can enhance the degradation of organic compounds and kill bacteria. Compared with other water treatment methods, the non-thermal plasma technology removes the pollutants completely and rapidly, and it does not introduce any new hazardous materials into the system. However, the high energy cost of non-thermal plasma technology prevents it from being commercialized. Therefore, many studies have been conducted to improve the energy efficiency of the non-thermal plasma technology. This dissertation focused on investigating the influence of operating conditions and the plasma properties on the production of H2O2 during the plasma discharge with liquid water. H2O2 is one of the most important products which indirectly indicates the concentration of ·OH generated by the plasma system. This work focused on the mechanism of H2O2 formation and analyzed the influence of plasma properties including the electron density and gas temperature on H2O2 production. The influence of operating conditions such as discharge power and carrier gases on plasma properties was also investigated. The results provide a general view of H2O2 formation in the plasma-liquid system and provide guidelines for modifying the plasma system to achieve higher efficiency. Another problem using non-thermal plasma to treat industrial waste water is that the high conductivity of waste water causes energy wastage since the current starts to flow through the liquid which generates heat. In addition, some plasma systems with low liquid conductivity tolerance cannot generate a discharge when liquid conductivity is high. Therefore, another goal of this work is to study the influence of liquid conductivity on plasma discharge with water and improve the liquid conductivity tolerance of the plasma system.
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Date Issued: 2018
Identifier: 2018_Fall_Wang_fsu_0071E_14831
Format: Thesis

Title: Modeling and Optimization of Parabolic Trough Solar Collectors.
Creator: Sensoy Cellat, Tugba Serpil, Ordóñez, Juan Carlos, Li, Hui, Guo, Wei, Hollis, Patrick J., Florida State University, College of Engineering, Department of Mechanical Engineering
Abstract/Description: A dynamic three-dimensional volume element model (VEM) of a parabolic trough solar collector (PTC) comprising an outer glass cover, annular space, absorber tube, and heat transfer fluid is studied with detail. The model is coupled with an existing semi-finite optical model for the purpose of simulation and optimization. The spatial domain in the VEM is discretized with lumped control volumes (i.e., volume elements) in cylindrical coordinates according to the predefined collector geometry....
Show moreA dynamic three-dimensional volume element model (VEM) of a parabolic trough solar collector (PTC) comprising an outer glass cover, annular space, absorber tube, and heat transfer fluid is studied with detail. The model is coupled with an existing semi-finite optical model for the purpose of simulation and optimization. The spatial domain in the VEM is discretized with lumped control volumes (i.e., volume elements) in cylindrical coordinates according to the predefined collector geometry. Therefore, the spatial dependency of the model is taken into account without the need to solve partial differential equations. The proposed model combines principles of thermodynamics and heat transfer as well as empirical heat transfer correlations, to simplify the modeling and expedite the computations. The resulting system of ordinary differential equations is integrated in time, yielding temperature fields which can be visualized and assessed with scientific visualization tools. The current model is validated with experimental data provided in the literature. The model was employed to evaluate the sensitivity of the collector performance described by the first and second law efficiencies to receiver length, annulus gap spacing, concentration ratio, incidence angle, inlet fluid temperature, and flow rate. This work also examined the effects of inlet fluid temperature and temperature differential on dynamic collector performance in the transient case study. Results showed that the first law efficiency was most sensitive to the inlet fluid temperature with the maximum variation of 30%, whereas the incidence angle and concentration ratio affected the second law efficiency the most with the maximum variations of 375% and 300%, respectively. The effect of the remaining parameters were trivial in all cases. In the transient analysis, higher temperature differential and lower inlet fluid temperature yielded higher total heat gain while the total exergy gain was insensitive to both parameters. The first law efficiency should therefore be of greater importance than the second law efficiency in the control of dynamic collector performance based on these two parameters. Furthermore, a sensitivity analysis of vemPTC is done with the Fourier amplitude sensitivity testing (FAST) for selected nine parameters. Cover transmittance shows a highly sensitive parameter within the rest of the selected parameters. After this sensitivity analysis, a multi-objective sensitivity analysis is studied for different heat transfer fluids such as synthetic oils, molten salts, liquid metals, nanofluids, and gases. Sobol sampling method is used for a multi-objective sensitivity analysis of different heat transfer fluids except for nanofluids, because it is more accurate to use a different methodology for sensitivity analysis of nanofluids, due to the effects of specific parameters on both first and second law efficiency. The fluid inlet temperature is a common sensitive parameter for almost all heat transfer fluids. Therefore, a multi-objective optimization study is done with four parameters and the results of it are presented in Chapter Four. Moreover, Chapter Five shows enhancement of the efficiency of both traditional parabolic trough solar collector (PTC) and transparent insulation material integrated PTC in both one and two dimensional model. Altering model types, operating conditions, or making an assumption for some used correlations is studied in the last chapter of this dissertation. After comparing the 1D and the 2D model, the results show that the most promising model type of PTC is the 2D model with TIM integrated one with correlation due to its stability for predicted efficiency. That approved that simplifying the model types may affect the results even though sufficiently accurate results are obtained with a simplified model. Temperature-dependent parameters should be selected for temperature sensitive variable in order to reach precise results.
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Date Issued: 2018
Identifier: 2018_Fall_SensoyCellat_fsu_0071E_14828
Format: Thesis

Title: Scalable Manufacturing of Lightweight Morphing Structures Using Carbon Nanotube Buckypaper.
Creator: DeGraff, Joshua, Liang, Zhiyong, Hruda, Simone Peterson, Cottinet, Pierre-Jean, Zeng, Changchun, Vanli, Omer Arda, Florida State University, College of Engineering, Department...
Show moreDeGraff, Joshua, Liang, Zhiyong, Hruda, Simone Peterson, Cottinet, Pierre-Jean, Zeng, Changchun, Vanli, Omer Arda, Florida State University, College of Engineering, Department of Industrial and Manufacturing Engineering
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Abstract/Description: Intelligent morphing structures will revolutionize micro-robotics, wearable technology, and tiny electro-mechanical systems. The ideal morphing structure is thin and flexible with the ability to deform and sense its surroundings. Biological organisms provide the inspiration for this kind of technology. By developing a low-profile film that changes shape and detects ambient conditions, it will provide leeway to mimicking the way organisms move throughout various mediums and terrains, while...
Show moreIntelligent morphing structures will revolutionize micro-robotics, wearable technology, and tiny electro-mechanical systems. The ideal morphing structure is thin and flexible with the ability to deform and sense its surroundings. Biological organisms provide the inspiration for this kind of technology. By developing a low-profile film that changes shape and detects ambient conditions, it will provide leeway to mimicking the way organisms move throughout various mediums and terrains, while deliberating their next actions according to the current environment and the actions that they have previously attempted. This dissertation will introduce carbon nanotube buckypaper as a key material in facilitating intelligent morphing schemes. In this research, a scalable manufacturing process for producing buckypaper composite actuators is introduced. The process can produce large batches of actuators at a time; this is critical for designing complex morphing structures in the future. The research also includes the electro-chemical modelling of the buckypaper composite actuator. Many researchers have introduced their own designs for actuators; however, most actuators lack the sensing component needed to be considered in morphing structures. This research will introduce a scalable method for buckypaper strain sensors as well. The sensors can detect micro-strains with higher sensitivity than commercial strain gauges. They can also detect finger movements and micro-strains in carbon composite materials. The overall objective is to synchronize the two devices so that a closed-loop system can provide corrections to the actuators movements. This research is essential to progressing low-profile morphing structures.
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Date Issued: 2018
Identifier: 2018_Su_Degraff_fsu_0071E_14511
Format: Thesis

Title: Resilience of Transportation Networks Subject to Bridge Damage and Road Closures.
Creator: Twumasi-Boakye, Richard, Sobanjo, John Olusegun, Chicken, Eric, Moses, Ren, Ozguven, Eren Erman, Florida State University, College of Engineering, Department of Civil and...
Show moreTwumasi-Boakye, Richard, Sobanjo, John Olusegun, Chicken, Eric, Moses, Ren, Ozguven, Eren Erman, Florida State University, College of Engineering, Department of Civil and Environmental Engineering
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Abstract/Description: Resilience simply means to rebound when exposed to a disruptive event. Damage to bridges in transportation networks usually result in long detours and increased travel time hence have massive cost implications. Transportation networks composed of major bridge infrastructures frequently depend on the bridges to carry high traffic volumes. Transportation network resilience explains the ability of transportation networks to contain and recover from disruptions. Transportation network resilience...
Show moreResilience simply means to rebound when exposed to a disruptive event. Damage to bridges in transportation networks usually result in long detours and increased travel time hence have massive cost implications. Transportation networks composed of major bridge infrastructures frequently depend on the bridges to carry high traffic volumes. Transportation network resilience explains the ability of transportation networks to contain and recover from disruptions. Transportation network resilience entails the transportation network’s capability to continue functioning in spite of hazard-induced breakdown to network segments and how quickly those sections can be restored for the network to return to pre-disaster performance levels. Most resilience-related research in this area have primarily focused on physical bridge resilience without necessarily considering the resilience impact of bridge damage on the overall or regional network. This thesis is focused on filling this research gap by considering the resilience of transportation networks subject to bridge damage and road closures. This research further proposes the use of regional travel demand models and Geographic Information Systems (GIS) visualization techniques for network level impact visualization and accessibility analyses. The socio-technical approach associated with transportation system resilience is broad and multidisciplinary, focusing on the network’s ability to sustain functionality and recover speedily when faced with disruptions or shocks. Academic works in this area are generally viewed in terms of having qualitative or quantitative frameworks. There is also significantly less literature evaluating response and recovery phases of resilience. Developed resilience indexes have sparsely touched on many salient aspects of resilience; hence they are only applicable to very specific scenarios. Further investigative efforts are therefore necessary for post-disaster phases of resilience, evaluating the applicability of resilience indexes on multiple hazard events for transportation networks, and developing resilience indexes based on regional road network models while considering all network links and not just alternative routes. Temporary, long-term, and partial closures to bridges can result in enormous cost implications. However, bridge closures are inevitable not only due to the likelihood of hazard-induced damages, but routine maintenance, repair, and rehabilitation (MR&R) activities may also warrant closures. It is a current practice that vehicles are rerouted to the shortest alternative route (detour approach) during bridge closures. In an initial study, a scenario-based network approach for evaluating the impact of bridge closures on transportation user cost is proposed. Both the detour-based and network-based approaches were applied to the Tampa Bay regional network model while considering five bridge closure scenarios. User costs were computed in terms of delay and vehicle operating costs. Findings indicated that for closures to I-275, Gandy, Highway 580 and W.C.C Causeway bridges, there were increases of about 42%, 18%, 61%, and 45% respectively, in total user costs for the network-based approach when compared with the current detour-only approach, indicating a significant network impact captured by the network-based approach. The proposed methodology captures the effects of bridge closures on all road segments within the regional network jurisdiction, provides a more rigid framework for analysis by ensuring user costs are computed efficiently while avoiding overestimation, takes into account the fact that road users may have advance knowledge of roadway conditions prior to trips hence significantly influencing route choices, and provides sufficient information for agencies to implement preemptive measures to cater for network-level disruptions due to bridge closures. Also, regional network resilience was assessed, first through a schematic framework developed for selecting at-risk bridges during hurricane events by: (i) computing exposure probabilities for hurricane events at bridge locations; (ii) developing bridge damage state functions and damage state rating assignments using historical data from the National Bridge Inventory (NBI) database; (iii) identification of bridges at risk to hurricane-induced damage; and (iv) computing aging accessibility to hospitals from which resilience was measured. Results indicated an increase from about 1200 minutes to 2100 minutes and from about 900 to 1100 minutes, for the congested travel time (CTT) and free flow travel time (FFTT), respectively, representing about 75% and 15% for CTT and FFTT, respectively. Furthermore, an additional total travel distance of 52.85 miles was observed for CTT and FFTT. The mean travel times after bridge closures increased from 8.43 to 15.1 minutes and from 6.6 to 7.76 minutes for CTT and FFTT, respectively. The resulting resilience index scaled from 0 to 1 was computed with 1 representing a network which can recover immediately after a disruption (or a network without any performance loss) and zero for one that may never recover to its pre-disaster form. Restoration to moderately damaged bridge led to functionality improvement from 0.87 to 0.94 considering FFTT, and from 0.57 to 0.83 considering the CTT. Reinstating extensively-damaged bridges resulted in functionality increase from 0.94 to 0.96, and 0.83 to 0.85, respectively, for FFTT and CTT. The resilience index for this study was computed as 0.94 and 0.81 for FFTT and CTT respectively, implying a significant loss in senior mobility hence the need for mitigation measures A framework for assessing the regional network resilience was developed by leveraging scenario-based traffic modeling and Geographic Information System (GIS) techniques. High impact zones location identification metrics were developed and implemented in preliminarily identifying areas affected by bridge closures. Resilience index measures were developed by utilizing practical functionality metrics based on vehicle distance and hours traveled. These are illustrated for the Tampa Bay area. Findings for ten bridge closure scenarios and recovery schemas indicate substantial regional network functionality losses during closures. I-275 bridge closure yielded the highest functional loss to the regional network: the aggregated resilience index below 0.5 reflects severe network performance deficit and mobility limitations. Closure to the WCC Causeway bridge results in a network level resilience index value of 0.87, while the indexes for the other scenarios range between 0.76 and 0.97. These results reflect the high dependency of the network on the I-275 bridge. Damage to this bridge is foreseen to have a massive impact on the network in terms of travel cost. Lower resilience index values imply either significant functionality losses or lengthy closure durations or both. To demonstrate the proposed methodology, a hypothetical network illustration indicated that: (i) Single bridge closure scenarios recorded significant performance losses for bridges which directly connected to the destination zone; (ii) Resilience indexes echoed the need to compare predicted recovery times to scheduled restoration times since index measures are either compensated or penalized the speed of predicted recovery with respect to scheduled recovery durations; (iii) Sensitivity analyses reinforced the previous assertion by accounting for both performance loss and restoration or recovery times; (iv) Multiple closures had a significant impact on network performance hence rapidity is vital in improving network resilience. Like any study, there are some limitations identified in this research. While it was clearly identified that variation in response and recovery times may have a significant impact on explaining and formulating resilience measures, there is insufficient data on the road closure and bridge closure durations after hazard events. Such databases will help researchers in evaluating resilience more accurately. Furthermore, even though case studies in this thesis took into account large networks, the utilized models were based on static traffic assignment which suffices for long-term transportation planning. However, it is recommended that use of dynamic traffic assignment models should be explored since they are known to reflect more accurate travel times. This is especially important for equity-based case study applications with respect to post-disaster accessibility. The use of user equilibrium assignment which accounts for each road user minimizing his or her travel time was used for this study, it is recommended that the system optimal solution which minimizes the overall network travel time should be considered since it may be of specific interest to agencies. Solution-based resilience studies are encouraged, especially efforts which incorporate the influx of connected and autonomous vehicles and other shared mobility solutions. This study also recognized the need for collaborative efforts between management authorities and researchers to facilitate the development and implementation of necessary policies and systems for the enhancement of transportation systems’ resilience.
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Date Issued: 2018
Identifier: 2018_Su_TwumasiBoakye_fsu_0071E_14751
Format: Thesis

Title: Modelling 3-D Brain-like Tissues Using Human Stem Cell-Derived Vascular Spheroids, Cortical Spheroids and Microglia-like Cells.
Creator: Song, Liqing, Li, Yan, Tang, Hengli, Ma, Teng, Guan, Jingjiao, Florida State University, College of Engineering, Department of Chemical and Biomedical Engineering
Abstract/Description: Human cerebral organoids derived from induced pluripotent stem cells (iPSCs) provide novel tools for recapitulating the cytoarchitecture of human brain and for studying biological mechanisms of neurological disorders. However, the heterotypic interactions of neurovascular units, composed of neurons, pericytes, astrocytes, and brain microvascular endothelial cells, in brain-like tissues are less investigated, in addition, most cortical organoids lack a microglia component, the resident immune...
Show moreHuman cerebral organoids derived from induced pluripotent stem cells (iPSCs) provide novel tools for recapitulating the cytoarchitecture of human brain and for studying biological mechanisms of neurological disorders. However, the heterotypic interactions of neurovascular units, composed of neurons, pericytes, astrocytes, and brain microvascular endothelial cells, in brain-like tissues are less investigated, in addition, most cortical organoids lack a microglia component, the resident immune cells in the brain. The first objective of this study is to investigate the impacts of neurovascular interactions on the brain regional patterning in cortical spheroids and organoids derived from human iPSCs. The second objective is to engineer brain-region-specific organoids from hiPSCs incorporated with isogenic microglia-like cells in order to enhance brain-like microenvironments. Hybrid neurovascular spheroids were constructed by fusion of human iPSC-derived cortical neural progenitor cell (iNPC) spheroids, endothelial cell (iEC) spheroids, and the supporting mesenchymal stem cells (MSCs). Single hybrid spheroids were constructed at different iNPC: iEC: MSC ratios of 4:2:0, 3:2:1 2:2:2, and 1:2:3 in low-attachment 96-well plates, which can be promoted using Geltrex and hyaluronic acid hydrogels. The incorporation of MSCs upregulated the secretion levels of cytokines VEGF-A, PGE2, and TGF-β1. In addition, tri-cultured spheroids promoted the expression of TBR1 (deep cortical layer VI) and Nkx2.1 (ventral cells), and matrix remodeling genes, MMP2 and MMP3, as well as Notch-1, indicating the crucial role of matrix remodeling and cell-cell communications on cortical spheroid and organoid patterning. Moreover, tri-culture system elevated blood-brain barrier gene expression (e.g., GLUT-1), CD31 and tight junction protein ZO-1 expression. In the last part of this study, microglia-like cells were derived from hiPSCs using stage-wise growth factor induction into mesoderm. The derived microglia-like cells expressed several phenotypic markers, including CD11b, IBA-1, CX3CR1, and P2RY12, and phagocytosed micron-size super-paramagnetic iron oxide particles. Microglia-like cells were able to upregulate pro-inflammatory genes (TNF-α) and secrete anti-inflammatory cytokines (i.e., VEGF, TGF-β1, and PGE2) when stimulated with amyloid β 42 oligomers, lipopolysaccharides, or dexamethasone. Dorsal cortical (higher expression of TBR1 and PAX6) and ventral (higher expression of Nkx2.1 and Prox-1) spheroids/organoids were derived from the same hiPSC line, which displayed action potentials and synaptic activities. Co-culturing the isogenic microglia-like cells with the dorsal or ventral organoids showed differential migration ability, intracellular Ca2+ transients imaging, and the response to pro-inflammatory stimuli (ventral group had higher TNF-α expression). The whole study should advance our understanding of cellular interplay of the neurovascular unit in diseased human brain and the effects of microglia on brain tissue function and establish a transformative approach to modulate cellular microenvironment during neurogenesis toward the goal of treating various neurological disorders.
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Date Issued: 2018
Identifier: 2018_Su_Song_fsu_0071E_14673
Format: Thesis

Title: Application of Particle Tracking Velocimetry to Thermal Counterflow and Towed-Grid Turbulence in Helium II.
Creator: Mastracci, Brian, Guo, Wei, Piekarewicz, Jorge, Oates, William, Taira, Kunihiko, Florida State University, College of Engineering, Department of Mechanical Engineering
Abstract/Description: The superfluid phase of helium-4, known as He~II, is predominantly used to cool low-temperature devices. It transfers heat by a unique thermally driven counterflow of its two constituents, a classical normal fluid and an inviscid superfluid devoid of entropy. It also has potential use for economical reproduction and study of high Reynolds number turbulent flow due to the extremely small kinematic viscosity and classical characteristics exhibited by mechanically driven flow. A number of...
Show moreThe superfluid phase of helium-4, known as He~II, is predominantly used to cool low-temperature devices. It transfers heat by a unique thermally driven counterflow of its two constituents, a classical normal fluid and an inviscid superfluid devoid of entropy. It also has potential use for economical reproduction and study of high Reynolds number turbulent flow due to the extremely small kinematic viscosity and classical characteristics exhibited by mechanically driven flow. A number of diagnostic techniques have been applied in attempts to better understand the complex behavior of this fluid, but one of the most useful, flow visualization, remains challenging because of complex interactions between foreign tracer particles and the normal fluid, superfluid, and a tangle of quantized vortices that represents turbulence in the superfluid. An apparatus has been developed that enables application of flow visualization using particle tracking velocimetry (PTV) in conjunction with second sound attenuation, a mature technique for measuring quantized vortex line density, to both thermal counterflow and mechanically-driven towed-grid turbulence in He~II. A thermal counterflow data set covering a wide heat flux range and a number of different fluid temperatures has been analyzed using a new separation scheme for differentiating particles presumably entrained by the normal fluid ("G2") from those trapped on quantized vortices ("G1"). The results show that for lower heat flux, G2 particles move at the normal fluid velocity vn, but for higher heat flux all particles move at roughly vn/2 ("G3"). Probability density functions (PDFs) for G1 particle velocity vp are Gaussian curves with tails proportional to |vp|⁻³, which arise from observation of particles trapped on reconnecting vortices. A probable link between G1 velocity fluctuations and fluctuations of the local vortex line velocity has been established and used to provide the first experimental estimation of c₂, a parameter related to energy dissipation in He~II. Good agreement between the length of observed G2 tracks and a simple model for the mean free path of a particle traveling through the vortex tangle suggests that flow visualization may be an alternative to second sound attenuation for measurement of vortex line density in steady-state counterflow. Preliminary PTV and second sound data in decaying He~II towed-grid turbulence shows agreement with theoretical predictions, and enables reliable estimation of an effective kinematic viscosity and calculation of longitudinal and transverse structure functions, from which information about the energy spectrum evolution and intermittency enhancement can be obtained.
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Date Issued: 2018
Identifier: 2018_Fall_Mastracci_fsu_0071E_14818
Format: Thesis

Title: Active Control of High-Speed Free Jets Using High-Frequency Excitation.
Creator: Upadhyay, Puja, Alvi, Farrukh S., Hussaini, M. Yousuff, Kumar, Rajan, Clark, Jonathan E., Gustavsson, Jonas, Florida State University, College of Engineering, Department of...
Show moreUpadhyay, Puja, Alvi, Farrukh S., Hussaini, M. Yousuff, Kumar, Rajan, Clark, Jonathan E., Gustavsson, Jonas, Florida State University, College of Engineering, Department of Mechanical Engineering
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Abstract/Description: Control of aerodynamic noise generated by high-performance jet engines continues to remain a serious problem for the aviation community. Intense low frequency noise produced by large-scale coherent structures is known to dominate acoustic radiation in the aft angles. A tremendous amount of research effort has been dedicated towards the investigation of many passive and active flow control strategies to attenuate jet noise, while keeping performance penalties to a minimum. Unsteady excitation,...
Show moreControl of aerodynamic noise generated by high-performance jet engines continues to remain a serious problem for the aviation community. Intense low frequency noise produced by large-scale coherent structures is known to dominate acoustic radiation in the aft angles. A tremendous amount of research effort has been dedicated towards the investigation of many passive and active flow control strategies to attenuate jet noise, while keeping performance penalties to a minimum. Unsteady excitation, an active control technique, seeks to modify acoustic sources in the jet by leveraging the naturally-occurring flow instabilities in the shear layer. While excitation at a lower range of frequencies that scale with the dynamics of large-scale structures, has been attempted by a number of studies, effects at higher excitation frequencies remain severely unexplored. One of the major limitations stems from the lack of appropriate flow control devices that have sufficient dynamic response and/or control authority to be useful in turbulent flows, especially at higher speeds. To this end, the current study seeks to fulfill two main objectives. First, the design and characterization of two high-frequency fluidic actuators ($25$ and $60$ kHz) are undertaken, where the target frequencies are guided by the dynamics of high-speed free jets. Second, the influence of high-frequency forcing on the aeroacoustics of high-speed jets is explored in some detail by implementing the nominally 25 kHz actuator on a Mach 0.9 ($Re_D = 5\times10^5$) free jet flow field. Subsequently, these findings are directly compared to the results of steady microjet injection experiments performed in the same rig and to prior jet noise control studies, where available. Finally, limited acoustic measurements were also performed by implementing the nominally 25 kHz actuators on jets at higher Mach numbers, including shock containing jets, and elevated temperatures. Using lumped element modeling as an initial guide, the current work expands on the previous development of low-frequency (2-8 kHz) Resonance Enhanced Micro-actuators (REM) to design actuators that are capable of producing high amplitude pulses at much higher frequencies. Extensive benchtop characterization, using acoustic measurements as well as optical diagnostics using a high resolution micro-schlieren setup, is employed to characterize the flow properties and dynamic response of these actuators. The actuators produced high-amplitude output a range of frequencies, $20.3-27.8$ kHz and $54.8-78.2$ kHz, respectively. In addition to providing information on the actuator flow physics and performances at various operating conditions, the benchtop study serves to develop relatively easy-to-integrate, high-frequency actuators for active control of high-speed jets for noise reduction. Following actuator characterization studies, the nominally 25 kHz ($St_{DF} \approx 2.2$) actuators are implemented on a Mach 0.9 free jet flow field. Eight actuators are azimuthally distributed at the nozzle exit to excite the initial shear layer at frequencies that are approximately an order of magnitude higher compared to the \textit{jet preferred frequency}, $St_P \approx 0.2-0.3$. The influence of control on the mean and turbulent characteristics of the jet, especially the developing shear layer, is examined in great detail using planar and stereoscopic Particle Image Velocimetry (PIV). Examination of cross-stream velocity profiles revealed that actuation leads to strong, spatially coherent streamwise vortex pairs which in turn significantly modify the mean flow field, resulting in a prominently undulated shear layer. These vortices grow as they convect downstream, enhancing local entrainment and significantly thickening the initial shear layer. Azimuthal inhomogeneity introduced in the jet shear layer is also evident in the simultaneous redistribution and reduction of peak turbulent fluctuations in the cross-plane near the nozzle exit. Further downstream, control results in a global suppression of turbulence intensities for all axial locations, also evidenced by a longer potential core and overall reduced jet spreading. The resulting impact on the noise signature is estimated via far-field acoustic measurements. Noise reduction was observed at low to moderate frequencies for all observation angles. Direct comparison of these results with that of steady microjet injection revealed some notable differences in the initial development of streamwise vorticity and the redistribution of peak turbulence in the azimuthal direction. However, despite significant differences in the near nozzle aerodynamics, the downstream evolution of the jet appeared to approach near similar conditions with both high-frequency and steady microjet injection. Moreover, the impact on far-field noise was also comparable between the two injection methods as well as with others reported in the literature. Finally, for jets at higher Mach numbers and elevated temperatures, the effect of control was observed to vary with jet conditions. While the impact of the two control mechanisms were fairly comparable on non-shock containing jets, high-frequency forcing was observed to produce significantly larger reductions in screech and broadband shock-associated noise (BBSN) at select under-expanded jet conditions. The observed variations in control effects at different jet conditions call for further investigation.
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Date Issued: 2017
Identifier: FSU_FALL2017_Upadhyay_fsu_0071E_14154
Format: Thesis

Title: Evacuating and Sheltering Aging Populations: A GIS- and Optimization-Based Methodology.
Creator: Kocatepe, Ayberk, Ozguven, Eren Erman, Brown, Jeff R., Moses, Ren, Sobanjo, John Olusegun, Florida State University, College of Engineering, Department of Civil and...
Show moreKocatepe, Ayberk, Ozguven, Eren Erman, Brown, Jeff R., Moses, Ren, Sobanjo, John Olusegun, Florida State University, College of Engineering, Department of Civil and Environmental Engineering
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Abstract/Description: Evacuating individuals and allocating space in shelters are complex tasks that depend on disaster characteristics, roadway network characteristics, the demographics and socioeconomic status of people in the affected region, as well as the effectiveness of the emergency plans. This problem becomes even more challenging when special needs (access and functional needs) populations and those with pets are considered since they may require more time in the event of an evacuation along with more...
Show moreEvacuating individuals and allocating space in shelters are complex tasks that depend on disaster characteristics, roadway network characteristics, the demographics and socioeconomic status of people in the affected region, as well as the effectiveness of the emergency plans. This problem becomes even more challenging when special needs (access and functional needs) populations and those with pets are considered since they may require more time in the event of an evacuation along with more space in shelters. Satisfying the needs of aging victims during emergency evacuations is critical and requires extra attention in the presence of highly uncertain disaster conditions. During Irma, it was very hard to manage the evacuation of aging people who had disabilities and mobility restrictions, did have special needs or pets. This study develops a Geographical Information Systems (GIS)-based methodology to measure and assess the transportation accessibility of these critical facilities through a diverse set of case study applications in the State of Florida. This research presents a timely evaluation and assessment of aging-focused evacuations towards providing better decision support during emergency transportation operations. This analysis is applied on a case study application set in Florida with a focus on the delays, evacuation travel times and critical bottlenecks, which can be vital for aging victims’ safety and survival. This study also emphasizes the use of GIS-based maps and modeling scenarios in support of emergency evacuation operations, in order to both satisfy the needs of aging people and account for real-world disruptions such as road closures. Additionally, a variety of scenarios are constructed to simulate evacuating 65+ and 85+ populations living in the evacuation zone, providing dynamic congested travel times. Finally, a capacitated p-median optimization model is implemented to maximize the accessibility and capacity of the existing shelters for 85+ populations with special needs (access and functional needs) or pets. Results indicate that the location and allocations of people to shelters are sensitive to demographics and roadway conditions, and the accessibility to shelters can be improved for this group of people based on optimization model results. A contribution of the research will be the evaluation of emergency evacuation performance of the transportation network under multiple disaster scenarios and the detailed modeling of key transportation facilities where special needs would take place. By exploring the use of multi-layered approach for emergency operations, this research will also increase the performance in evacuating aging people who has limitations.
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Date Issued: 2017
Identifier: FSU_FALL2017_Kocatepe_fsu_0071E_14253
Format: Thesis

Title: Hirschman Transform Applications in Compressive Sensing.
Creator: Xi, Peng, DeBrunner, Victor E., Gallivan, Kyle A., Harvey, Bruce A., DeBrunner, Linda S., Roberts, Rodney G., Florida State University, College of Engineering, Department of...
Show moreXi, Peng, DeBrunner, Victor E., Gallivan, Kyle A., Harvey, Bruce A., DeBrunner, Linda S., Roberts, Rodney G., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: The CS technology has attracted considerable attention because it can surpass the traditional limit of Nyquist sampling theory. Rather than sampling a signal at a high frequency and then compressing it, the CS senses the target signal in a compressed format directly. However, the great sampling improvement results in the increased complexity in decoding. The optimization of sensing structure never stops to simplify the decoding procedure as much as possible. Unlike the Heisenberg-Weyl measure...
Show moreThe CS technology has attracted considerable attention because it can surpass the traditional limit of Nyquist sampling theory. Rather than sampling a signal at a high frequency and then compressing it, the CS senses the target signal in a compressed format directly. However, the great sampling improvement results in the increased complexity in decoding. The optimization of sensing structure never stops to simplify the decoding procedure as much as possible. Unlike the Heisenberg-Weyl measure, the Hirschman notion of joint uncertainty is based on entropy rather than energy. The Discrete Hirschman Transform (DHT) has been proved to be superior in complexity reduction and high resolution to the traditional Discrete Fourier Transform in many aspects such as fast filtering, spectrum estimation, and image identification. In this dissertation, I implement a new deterministic compressive sensing system based on DHT with four contributions: (1) apply Weyl's sum character estimation to the DHT matrices to develop a new deterministic sensing structure (2) theoretically prove that the new sensing structure satisfy the Mutual Incoherence Property (3) discover a Non-tensor Wavelet Transform as the sparse basis for DHT sensing structures as well as for other DFT and DFT-like sensing matrices. (4) design a DHT computational core based on FPGA and related communication suite based on C#.
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Date Issued: 2017
Identifier: FSU_FALL2017_XI_fsu_0071E_14193
Format: Thesis

Title: Designing Time Efficient Real Time Hardware in the Loop Simulation Using Input Profile Temporal Compression.
Creator: Chatterjee, Sourindu, Faruque, Md Omar, Steurer, Mischa, Li, Hui, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: The modern day smart grid technology relies heavily on data acquisition and analysis. A distributed controller governs smart microgrid functions with one or more renewable sources and smart controllable loads. This sort of intelligent, scalable system is the primary drive for the Energy Internet (EI). Hence, in modern-day power systems engineering to analyze, understand and make efficient system design choices that capture robustness and scalability, Hardware in the Loop (HIL) simulations are...
Show moreThe modern day smart grid technology relies heavily on data acquisition and analysis. A distributed controller governs smart microgrid functions with one or more renewable sources and smart controllable loads. This sort of intelligent, scalable system is the primary drive for the Energy Internet (EI). Hence, in modern-day power systems engineering to analyze, understand and make efficient system design choices that capture robustness and scalability, Hardware in the Loop (HIL) simulations are required. Real-Time Simulations (RTS) is the state of the art technology thrusting the capstone of innovation for this industry. As engineers, we can model, simulate and validate smart grids operations more rapidly, robustly and reliably using RTS. With enough smaller time step for the simulation, the boundary between the real and the simulated systems slowly vanishes. It also enables the system to be simulated as Controller Hardware in the Loop (CHIL) or Power Hardware in the Loop (PHIL) setups, evolving and imitating the real physical world. The HIL (Hardware in the Loop) setup also enables a real data source or sink to be in the system to form the loop of exchange between the simulated system and real-world hardware which is most often a control hardware. The implementation of such a setup is made possible at Center for Advanced Power Systems (CAPS), named as Hardware in the Loop Test-Bed (HIL-TB). This evaluation architecture provides a systematic solution to HIL simulations. Now the sampling time for real-world sensors is generally in the order of microseconds, enabling this collected data to emulate the cyber-physical domain accurately. Thus, the challenge previously was to address the throughput of real-world input data into the simulated system efficiently and correctly. The quality of the Design of Simulation (DoS) using the real world data in the form of Real Time Input Profile (RTIP), improves, affects the quality of response of the real-time cyber-physical system simulation. Thus great care needs to be taken to prepare, prune and project the RTIPs to improve and enhance the system performance evaluation index. To solve this problem, partially successful attempts have been made in the direction of machine learning by using methods like clustering and regression to characterize large input profiles or by breaking them into subsections using fixed length sliding window techniques. These classic methods then perform data analysis on those sub-pieces to distinguish among a variety of input profiles and assign an index. These sub-profiles or sections would be then loaded into the simulation as environmental input to represent the physical system in the HIL simulations. This traditional procedure is observed to be arbitrary because clustering algorithms and metrics for methods like regression or classification are user-defined and there exists no standard practice to deal with huge input profiles. There have also been confusions regarding the size of the sliding window to create subsections, subsection joining logic, etc. Thus, to address this issue, the primary focus of this study is to present a systematic, controlled, reliable procedure to explore, screen, crop large input profiles and then to compress the same by selecting sections with most relative importance using a modified version of “knapsack” dynamic programming algorithm. This compression primarily aims to shrink down the total simulation time without much loss of information. The latter part of this study focuses towards response driven performance evaluation of the HIL simulations. This is ensured by targeted compression of original input profile based on the certain requirement of the simulation. This approach ensures that the control algorithm (CHIL simulations) or any other system operator is driven in a specific direction in the simulation response space by effectively sampling the input parameters space. The fully automated HIL-TB evaluation framework aided with Input Profile Time Compression (IPTC) module delivers a fast-convergent validation for the performance evaluation with relatively similar system response. In this study, the IPTC module has been applied to seven load profiles to compress their temporal length by a third. The case study used for the simulation with these RTIPs is the Future Renewable Electric Energy Delivery and Management (FREEDM) IEEE seven node system. The test results show great coherence between the uncompressed and compressed response and validate the performance of the IPTC module applied to real-world HIL simulations. Thus, it can conclude that the functionality of the IPTC module is validated by the quality of simulation response gained out of the compressed simulation as compared to uncompressed simulation. In future, endeavors can be made in this path by expanding the functionality of this compression module to not only identifying and managing important sections based on some initial assumption about the objective of the control application but also providing cognitive, autonomous understanding of the behavior of the controls and using that knowledge accomplishing compression of large input profiles.
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Date Issued: 2017
Identifier: FSU_FALL2017_CHATTERJEE_fsu_0071N_14274
Format: Thesis

Title: Global Stability Analysis and Control of Compressible Flows over Rectangular Cavities.
Creator: Sun, Yiyang, Taira, Kunihiko, Yu, Weikuan, Cattafesta, Louis N., Ukeiley, Lawrence S., Lin, Shangchao, Florida State University, College of Engineering, Department of Mechanical...
Show moreSun, Yiyang, Taira, Kunihiko, Yu, Weikuan, Cattafesta, Louis N., Ukeiley, Lawrence S., Lin, Shangchao, Florida State University, College of Engineering, Department of Mechanical Engineering
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Abstract/Description: The present numerical investigation aims to uncover the inherent instability in compressible cavity flows and aid designs of effective flow control to alter undesirable flow features. Two-dimensional (2D) and three-dimensional (3D) global stabilities of compressible open-cavity flows are examined in detail, which provides insights into designs of active flow control to reduce the pressure fluctuations over the cavity. The stability characteristics of compressible spanwise-periodic open-cavity...
Show moreThe present numerical investigation aims to uncover the inherent instability in compressible cavity flows and aid designs of effective flow control to alter undesirable flow features. Two-dimensional (2D) and three-dimensional (3D) global stabilities of compressible open-cavity flows are examined in detail, which provides insights into designs of active flow control to reduce the pressure fluctuations over the cavity. The stability characteristics of compressible spanwise-periodic open-cavity flows are investigated with direct numerical simulation (DNS) and biglobal stability analysis for rectangular cavities with length-to-depth ratios of $L/D=2$ and 6. This study examines the behavior of instabilities with respect to stable and unstable steady states in the laminar regimes for subsonic as well as transonic conditions where compressibility plays an important role. It is observed that an increase in Mach number destabilizes the flow in the subsonic regime and stabilizes the flow in the transonic regime. Biglobal stability analysis for spanwise-periodic flows over rectangular cavities with large aspect ratio is closely examined in this study due to its importance in aerodynamic applications. Moreover, biglobal stability analysis is conducted to extract 2D and 3D eigenmodes for prescribed spanwise wavelengths $\lambda/D$ about the 2D steady state. The properties of 2D eigenmodes agree well with those observed in the 2D DNS. In the analysis of 3D eigenmodes, it is found that an increase of Mach number stabilizes dominant 3D eigenmodes. For a short cavity with $L/D=2$, the 3D eigenmodes primarily stem from centrifugal instabilities. For a long cavity with $L/D=6$, other types of eigenmodes appear whose structures extend from the aft-region to the mid-region of the cavity, in addition to the centrifugal stability mode located in the rear part of the cavity. A selected number of 3D DNS are performed at $M_\infty=0.6$ for cavities with $L/D=2$ and 6. For $L/D=2$, the properties of 3D structures present in the 3D nonlinear flow correspond closely to those obtained from linear stability analysis. However, for $L/D=6$, the 3D eigenmodes cannot be clearly observed in the 3D DNS, due to the strong nonlinearity that develops over the length of the cavity. In addition, it is noted that three-dimensionality in the flow helps alleviate violent oscillations for the long cavity. The analysis performed in this paper can provide valuable insights for designing effective flow control strategies to suppress undesirable aerodynamic and pressure fluctuations in compressible open-cavity flows. Three-dimensional nonlinear simulations (DNS and LES) are also conducted to examine influence of cavity width, sidewall boundary conditions, free stream Mach numbers, and Reynolds numbers on open-cavity flows. DNS and large eddy simulations (LES) are performed with $L/D=6$, width-to-depth ratios of $W/D$=1 and 2 for Reynolds number of $Re_D = 502$ and $10^4$. To numerically study the effects of cavity width on the flows, we consider (1) 2D cavities with spanwise periodicity and (2) finite-span cavities with no-slip adiabatic walls. Furthermore, the analyses are conducted for subsonic ($M_\infty=0.6$) and supersonic ($M_\infty=1.4$) speeds to reveal compressibility effects. It is found that, at low $Re_D=502$, widening the cavity can decrease the velocity fluctuations of the flow by introducing spanwise variations in the shear layer to reduce the kinetic energy from spanwise vortices associated with Rossiter modes. Both velocity and pressure fluctuations decrease in the finite-span cavity compared to those with spanwise periodic boundary conditions. With the characteristics of base flows revealed, flow control is implemented for turbulent cavity flows where steady blowing is introduced along the leading edge of the cavity for both subsonic ($M_\infty=0.6$) and supersonic ($M_\infty=1.4$) flows. We examine how the actuations interact with the flows and reduce the velocity and pressure fluctuations with and without sidewalls. From the control study, we find that pressure reduction on the cavity surfaces can be achieved in an effective manner by taking advantage of 3D flow physics.
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Date Issued: 2017
Identifier: FSU_FALL2017_Sun_fsu_0071E_14244
Format: Thesis

Title: Small Signal Instability Assessment and Mitigation in Power Electronics Based Power Systems.
Creator: Ye, Qing, Li, Hui, Collins, E. (Emmanuel), Steurer, Mischa, Yu, Ming, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: Power electronics technology has been widely used in electric power system to achieve high energy efficiency and high renewable energy penetration. Small signal instability phenomena could easily occur in systems with abundant power electronics because of high order passive elements and controller interactions among power converters. These instability issues degrade power quality or even cause system failure. Therefore it is necessary to build accurate small signal models for stability...
Show morePower electronics technology has been widely used in electric power system to achieve high energy efficiency and high renewable energy penetration. Small signal instability phenomena could easily occur in systems with abundant power electronics because of high order passive elements and controller interactions among power converters. These instability issues degrade power quality or even cause system failure. Therefore it is necessary to build accurate small signal models for stability analysis and develop effective resonance mitigation techniques for stability improvement. The general stability analysis methods including eigenvalues-based method, component connection method, passivity-based method and impedance-based method have been evaluated and summarized. The impedance-based method is selected as the stability analysis tool for this research due to its advantages compared to other methods. Besides, three popular resonance suppression techniques, i.e. passive damper, active damper and virtual impedance control, are also studied and evaluated. The virtual impedance control is of interest because it does not reduce system efficiency or reliability compared to both the passive and active damper. A unified impedance-based stability criterion (UIBSC) has been proposed for paralleled grid-tied inverters. Compared to the traditional IBSC which evaluates all minor loop gains (MLGs) of individual inverter, the UIBSC assesses the derived global minor loop gain (GMLG) only once to determine system stability. As a result, the computation efforts can be significantly reduced when system contains a large number of inverters. In addition, a stability-oriented design guideline has been derived for the paralleled grid-tied inverters based on the GMLG. By using the guideline, the grid impedance, inverter filter parameters, time delays of digital control and control parameters can be analyzed or designed to meet the system stability requirement. The small signal stability of the FREEDM system is a critical issue due to the abundant power electronics devices and flexible control strategies. The impedance modeling methods for current controlled inverters, inverter stage of the SST, DAB converters are developed. The influences of control schemes on power converter terminal behaviors are analyzed as well. Stability criteria for several types of grid enabled by the SST are derived. The bidirectional power flow effect is also considered. These instability phenomena are demonstrated in ac, dc, and hybrid ac/dc grids of FREEDM system using HIL test bed. Finally, the conclusions are given and the scope of future work is discussed.
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Date Issued: 2017
Identifier: FSU_FALL2017_Ye_fsu_0071E_14130
Format: Thesis

Title: Three Dimensional Control of High-Speed Cavity Flow Oscillations.
Creator: Zhang, Yang, Cattafesta, Louis N., Tam, Christopher K. W., Taira, Kunihiko, Collins, E. (Emmanuel), Florida State University, College of Engineering, Department of Mechanical...
Show moreZhang, Yang, Cattafesta, Louis N., Tam, Christopher K. W., Taira, Kunihiko, Collins, E. (Emmanuel), Florida State University, College of Engineering, Department of Mechanical Engineering
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Abstract/Description: Cavity structures, like weapons bays and landing gear wells on aircraft, suffer from severe oscillations under high speed flow conditions. These oscillations are associated with intense surface pressure/velocity fluctuations inside the cavity which can radiate strong acoustic waves and cause structural damage. The physics of cavity flows have been studied for several decades with much of the effort put towards flow controls to reduce these oscillations. Geometric modifications of the cavity...
Show moreCavity structures, like weapons bays and landing gear wells on aircraft, suffer from severe oscillations under high speed flow conditions. These oscillations are associated with intense surface pressure/velocity fluctuations inside the cavity which can radiate strong acoustic waves and cause structural damage. The physics of cavity flows have been studied for several decades with much of the effort put towards flow controls to reduce these oscillations. Geometric modifications of the cavity structure are usually only effective for suppressing the oscillations within the designed flow conditions. Therefore, active flow control is more attractive for a wider application range. Previous research have proven that mass/momentum injection at the cavity leading edge can effectively suppress the pressure/velocity fluctuations. Due to the limited control authorities of current actuators, a steady actuation which introduces three-dimensional disturbances is studied to reduce the energy requirements of the actuator and improve the suppression of the oscillations over a wide range of free-stream Mach numbers. Surface fluctuating pressure measurements are acquired to determine the control performances of a number of 3-D actuation configurations. Flow fields, including velocity fields and density gradient fields, are measured to reveal the flow features with and without the flow control. Mathematical methods, including modal decomposition analysis, are further applied to study the dynamics of the flow field. All of these analyses together elucidate the effective 3-D actuation mechanism in the cavity flow control. The suppression of pressure fluctuations are obtained in both full-span and finite-span cavities. The successful flow control is found to be the redistribution of the energy in the shear layer by the counter-rotating-vortex pairs, which are introduced by the 3-D actuation in the cross-flow. In addition, a design guide for the actuator geometry is given based on the observations.
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Date Issued: 2017
Identifier: FSU_FALL2017_ZHANG_fsu_0071E_14127
Format: Thesis

Title: Optimization of Groundwater Long-Term Monitoring Network Optimization of Groundwater Long-Term Monitoring Network with Ant Colony Optimization with Ant Colony Optimization.
Creator: Liu, Xiaoli, Chen, Gang, Ye, Ming, Wang, Xiaoqiang, Hilton, Amy B. Chan, Huang, Wenrui, Tang, Youneng, Florida State University, College of Engineering, Department of Civil and...
Show moreLiu, Xiaoli, Chen, Gang, Ye, Ming, Wang, Xiaoqiang, Hilton, Amy B. Chan, Huang, Wenrui, Tang, Youneng, Florida State University, College of Engineering, Department of Civil and Environmental Engineering
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Abstract/Description: Groundwater remediation is conducted in polluted sites to remove contaminants and to restore ground water quality. After remediation goals are achieved, long-term groundwater monitoring (LTM) that can span decades is required to assess the concentration of residual contaminants and to avoid the risk of human health and environment. On large remediation sites, the cost for maintaining a LTM network, collecting samples, conducting water quality lab analysis can be a significant, persistent and...
Show moreGroundwater remediation is conducted in polluted sites to remove contaminants and to restore ground water quality. After remediation goals are achieved, long-term groundwater monitoring (LTM) that can span decades is required to assess the concentration of residual contaminants and to avoid the risk of human health and environment. On large remediation sites, the cost for maintaining a LTM network, collecting samples, conducting water quality lab analysis can be a significant, persistent and growing financial burden for the private entities and government agencies who are responsible for environmental remediation projects. LTM network optimization offers an opportunity to improve the cost-effectiveness of the LTM effort while meeting data accuracy requirements. The optimization includes identifying the redundancy in the monitoring network, and recommending changes to protect against potential impacts to the public and the environment. This study develops a variant ant colony optimization (VACO) method, using ordinary kriging (OK) or inverse distance weighting (IDW) for data interpolation, to identify optimal LTM networks that minimize the cost of LTM by reducing the number of monitoring locations with minimum overall data loss. ACO is a global stochastic search method inspired by the collective problem-solving ability of a colony of ants as they search for the most efficient routes from their nests to food sources. The performance of ACO variant (VACO) developed in this study is evaluated separately in two test cases. In the first case, VACO is used to solve a simplified traveling sales person problem. In the second case, both enumeration method and VACO are employed for optimization of a synthetic long term monitoring network of 73 wells generated from a groundwater transport simulation model. The two sets of test show that the VACO performs well for optimization problems. The VACO is finally adopted for the optimization of a long term monitoring network of 30 wells in Logistic Center, Washington, with the data interpolation methods of inverse distance weighing, ordinary kriging, and modified inverse distance weighing which is developed in this study. The optimization results are analyzed and group of ideal redundant wells identified. The conclusion of this study is summarized at the end, and future work is suggested.
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Date Issued: 2017
Identifier: FSU_FALL2017_Liu_fsu_0071E_14254
Format: Thesis

Title: Uncertainty Analysis of Multifunctional Constitutive Relations and Adaptive Structures.
Creator: Miles, Paul R., Oates, William, Hussaini, M. Yousuff, Zeng, Changchun (Chad), Taira, Kunihiko, Lin, Shangchao, Smith, Ralph C., Florida State University, College of Engineering,...
Show moreMiles, Paul R., Oates, William, Hussaini, M. Yousuff, Zeng, Changchun (Chad), Taira, Kunihiko, Lin, Shangchao, Smith, Ralph C., Florida State University, College of Engineering, Department of Mechanical Engineering
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Abstract/Description: Practically all engineering applications require knowledge of uncertainty. Accurately quantifying uncertainty within engineering problems supports model development, potentially leading to identification of key risk factors or cost reductions. Often the full problem requires modeling behavior of materials or structures from the quantum scale all the way up to the macroscopic scale. Predicting such behavior can be extremely complex, and uncertainty in modeling is often increased due to...
Show morePractically all engineering applications require knowledge of uncertainty. Accurately quantifying uncertainty within engineering problems supports model development, potentially leading to identification of key risk factors or cost reductions. Often the full problem requires modeling behavior of materials or structures from the quantum scale all the way up to the macroscopic scale. Predicting such behavior can be extremely complex, and uncertainty in modeling is often increased due to necessary assumptions. We plan to demonstrate the benefits of performing uncertainty analysis on engineering problems, specifically in the development of constitutive relations and structural analysis of smart materials and adaptive structures. This will be highlighted by a discussion of ferroelectric materials and their domain structure interaction, as well as dielectric elastomers’ viscoelastic and electrostrictive properties.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Miles_fsu_0071E_14033
Format: Thesis

Title: Driver Behavior in Mixed Connected-Automated and Conventional Vehicle Traffic at a Freeway Merge.
Creator: Chityala, Sneha, Sobanjo, John Olusegun, Ozguven, Eren Erman, Spainhour, Lisa, Florida State University, College of Engineering, Department of Civil and Environmental Engineering
Abstract/Description: Wireless communication through automated and connected vehicles is an evolving technology. This ameliorates the driving conditions, reduces time spent in traffic and curtails the crash occurrences. One of the most challenging areas, where these interactions can be most useful, are freeway merge ramps. Both the drivers on mainline and the drivers merging would be skeptical about their decisions at this location. The drivers who want to merge to the freeway mainline would seek to find an...
Show moreWireless communication through automated and connected vehicles is an evolving technology. This ameliorates the driving conditions, reduces time spent in traffic and curtails the crash occurrences. One of the most challenging areas, where these interactions can be most useful, are freeway merge ramps. Both the drivers on mainline and the drivers merging would be skeptical about their decisions at this location. The drivers who want to merge to the freeway mainline would seek to find an appropriate gap to enter the mainline of the freeway. While the technology of connected and automated vehicles is being promoted, the reality now is that for the foreseeable future, the traffic would not comprise 100% of such connected and automated vehicles. In other words, there will be a mixed traffic of manually-driven and connected/automated vehicles, with various levels of automation in the latter types of vehicles. Capturing the driver behavior at the merge locations into a freeway with such mixed traffic, will be useful in learning and improving safety on the roadways. The Driving Simulator is a useful device in capturing driver behaviors. In this study scenarios are developed in the Driving Simulator which allows mixed traffic on mainline and also observe the driver behaviors from the ramp onto the merge. Overall there were three variations in the mixed traffic flow for the mainline freeway: 0%, 50% and 75% penetration rates. The freeway traffic was generated for the mixed traffic by first developing a mixed probability distribution which assumes exponential distributions for the inter-arrival times of manually-driven vehicles and a constant headway (uniform distribution) is assumed between connected vehicles. The mixed distribution was then used to randomly generate vehicles through Monte Carlo simulation, with assigned headways in the Driving Simulator for the various connected vehicle penetration rates. The subject driver’s speed along the ramp is monitored, as well as the speeds of those vehicles on the freeway. The gaps between freeway vehicles, which were accepted by the subject driver, were recorded for the various situations and scenarios. There were a total of 41 participants, with 29 young drivers (younger than 65 years) and 12 elderly drivers (65 years and older, amongst which 2 were between 55 and 65 years old). Three scenarios were presented to the drivers. The first driving task was to determine headway gap acceptance for the three penetration rates, based on the perception of the subject drivers (without driving). The second test involved the subjects actually driving on the ramp and implementing a suitable gap to merge on the freeway traffic at each ramp. From the data collected, the critical gaps were estimated based on perception. The gaps accepted while driving were also tabulated analyzed. It was observed that the critical gap for the young drivers in 0%, 50%, 75% penetrations rate are 2.9 sec, 1.8 sec, and 1.7 sec respectively. The critical gaps observed for elderly drivers aged over 65 are 3.5 sec, 2.0 sec, and 1.9 sec respectively. Based on an Analysis of Variance (ANOVA), there is no evidence to prove the equality of means for different groups classified by age, gender and driving experience in both perception and actual driving conditions for 0% and 50% penetration rates. It was observed that the headway gaps accepted by young and drivers, both by perception and driving in 0% penetration rate were 2.39 sec and 2.35 sec respectively. The headway gaps accepted by elderly drivers both by perception and driving in 0% penetration rate were 2.4 sec and 2.72 sec respectively. When the ANOVA was performed between the 0% and 50% penetration rates of driving conditions, it was observed that there is a lot of variation in the mean headway gaps accepted. The values of average headway gaps accepted for young drivers were estimated as 2.36 sec and 1.53 sec respectively, in the 0% and 50% penetration rates. For the elderly drivers the average headway gap values observed were 2.72 sec and 1.55 sec respectively, in the 0% and 50% penetration rates traffic. The results also indicated the subject driver acceleration and deceleration behavior at the merge ramp. The results also showed that when the (aggressive) drivers accelerated to match the velocity of mainline traffic and merged in between connected-automated vehicles with the shortest gap, effects were noticed on the mainline traffic, where the main line traffic had to decelerate rapidly. Overall, it was observed that the subject drivers accepted shorter headway gaps as the penetration rates increases.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Chityala_fsu_0071N_14121
Format: Thesis

Title: Development of a Simple Microfluidic Device for Characterizing Chemotaxis of Macrophage in Response to Myelin Basic Protein.
Creator: Jia, Xiaolin, Chung, Hoyong, Mohammadigoushki, Hadi, Florida State University, College of Engineering, Department of Chemical and Biomedical Engineering
Abstract/Description: Microfluidic devices are widely used for cell-based analysis. There are always needs to develop simpler, more effective and/or less costly devices than the existing ones for this application. A simple microfluidic device has been fabricated and tested for studying chemotaxis of macrophages in this study. The device was made of polydimethylsiloxane bound to a cell culture dish. It consisted of a millimeter-sized cavum and two arrays of straight channels of 5 um in width and 6um height and...
Show moreMicrofluidic devices are widely used for cell-based analysis. There are always needs to develop simpler, more effective and/or less costly devices than the existing ones for this application. A simple microfluidic device has been fabricated and tested for studying chemotaxis of macrophages in this study. The device was made of polydimethylsiloxane bound to a cell culture dish. It consisted of a millimeter-sized cavum and two arrays of straight channels of 5 um in width and 6um height and about two millimeters in length. The channels connected the cavum, in which a chemoattractant was loaded, with the surrounding environment, in which the macrophages were cultured. The device was first tested with a known chemoattractant - fetal bovine serum and the chemoattractive property of myelin basic protein (MBP) was then studied using the device. The macrophages were found to migrate towards to the MBP-loaded cavum in larger quantity and greater distance than those in the control samples. The results prove the usefulness of the microfluidic device for chemotaxis assay and indicate that MBP is a chemoattractant for the macrophages.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Jia_fsu_0071N_13978
Format: Thesis

Title: Experimental Characterization of Photoresponsive Azobenzene Polymers.
Creator: Chowdhury, Sadiyah Sabah, Oates, William, Lin, Shangchao, Ordóñez, Juan Carlos, Florida State University, College of Engineering, Department of Mechanical Engineering
Abstract/Description: Azobenzene is a photo responsive polymer which undergoes molecular change under exposure to certain wavelengths of light. This molecular shape change can cause an overall macroscopic shape change in an azobenzene polymer network. This promising photostrictive behavior has broad range of applications in flow control, robotics and energy harvesting applications. The conversion of solar energy directly into mechanical work provides unique capabilities in adaptive structures. In this thesis,...
Show moreAzobenzene is a photo responsive polymer which undergoes molecular change under exposure to certain wavelengths of light. This molecular shape change can cause an overall macroscopic shape change in an azobenzene polymer network. This promising photostrictive behavior has broad range of applications in flow control, robotics and energy harvesting applications. The conversion of solar energy directly into mechanical work provides unique capabilities in adaptive structures. In this thesis, stress measurements show that irradiated azo-LCN experience photochemical and thermomechanical stress. Experimental results show that stress response depends highly on the range of pre-stress applied and the threshold pre-stress differs for different polarization directions.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Chowdhury_fsu_0071N_13891
Format: Thesis

Title: Low Voltage Ride-through for Photovoltaic Systems Using Finite Control-Set Model Predictive Control.
Creator: Franco, Fernand Diaz, Edrington, Christopher S., Ordóñez, Juan Carlos, Faruque, Md Omar (Professor of Electrical and Computer Engineering), Foo, Simon Y., Florida State...
Show moreFranco, Fernand Diaz, Edrington, Christopher S., Ordóñez, Juan Carlos, Faruque, Md Omar (Professor of Electrical and Computer Engineering), Foo, Simon Y., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Grid codes impose immunity requirements to the generation systems that are connected to the transmission lines. Immunity refers to the generator’s capability to overcome grid abnormal conditions. One of the requirements is to remain connected during a certain time when a fault, like voltage sag, is presented. During the fault scenario, a generator unit should remain connected for a pre-determined amount of time, and also provide reactive power to support the grid voltage. This is called low...
Show moreGrid codes impose immunity requirements to the generation systems that are connected to the transmission lines. Immunity refers to the generator’s capability to overcome grid abnormal conditions. One of the requirements is to remain connected during a certain time when a fault, like voltage sag, is presented. During the fault scenario, a generator unit should remain connected for a pre-determined amount of time, and also provide reactive power to support the grid voltage. This is called low-voltage ride through (LVRT). Initially, LVRT requirements were imposed for large generator units like wind farms connected to the transmission network; however, due to the increased penetration of distributed generation (DG) on the distribution system, new grid codes extend the mentioned capability to generator units connected to the distribution grid. Due to matured photovoltaic (PV) technology and the decreased price of PV panels, PV grid tied installations are proliferating in the utility grids; this is creating new challenges related to voltage control. In the past, DG such as PV were allowed to trip from the grid when a fault or unbalance occurred and reconnect within several seconds (sometimes minutes) once the fault had been cleared. Nevertheless, thanks to high PV penetration nowadays, the same method cannot be used because it will further deteriorate the power quality and potentially end in a power blackout. Different approaches have been considered to fulfill the LVRT requirement on PV systems. A large amount of literature focuses on the control of the grid side converter of the PV installation rather than the control of PV operation during the fault, and most control designs applied to the grid side follow classical control methods. Moreover, the effects of the grid fault on the generator side impose a challenge for controlling the PV systems since the quality of the synthesized converter voltages and currents depends on the dc link power/voltage control. This document proposes a Model based Predictive Control (MPC) for controlling a two stage PV system to fulfill LVRT requirements. MPC offers important advantages over traditional linear control strategies since the MPC cost function can include constraints that are difficult to achieve in classical control. Special attention is given to implementation of the proposed control algorithms. Simplified MPC algorithms that do not compromise the converter performance and immunity requirement are discussed.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_DiazFranco_fsu_0071E_14045
Format: Thesis

Title: Modeling and Application of Effective Channel Utilization in Wireless Networks.
Creator: Ng, Jonathan, Yu, Ming (Professor of scientific computing), Zhang, Zhenghao, Harvey, Bruce A., Andrei, Petru, Florida State University, College of Engineering, Department of...
Show moreNg, Jonathan, Yu, Ming (Professor of scientific computing), Zhang, Zhenghao, Harvey, Bruce A., Andrei, Petru, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: As a natural scarcity in wireless networks, radio spectrum becomes a major investment in network deployment. How to improve the channel utilization (CU) of the spectrum is a challenging topic in recent research. In a network environment, the utilization of a channel is measured by the effective CU (ECU), i.e., the effective time for transmission or when the medium being sensed busy over its total operation time. However, existing work does not provide a valid model for ECU. We investigate the...
Show moreAs a natural scarcity in wireless networks, radio spectrum becomes a major investment in network deployment. How to improve the channel utilization (CU) of the spectrum is a challenging topic in recent research. In a network environment, the utilization of a channel is measured by the effective CU (ECU), i.e., the effective time for transmission or when the medium being sensed busy over its total operation time. However, existing work does not provide a valid model for ECU. We investigate the relationship between ECU and the interference from other wireless transmission nodes in a wireless network, as well as from potential malicious attacking interfering sources. By examining the relationship between their transmission time and co-transmission time ratios between two or more interferers, we propose a new model based on the channel occupation time of all nodes in a network. The model finds its mathematical foundation on the set theory. By eliminating the overlapping transmission time intervals instead of simply adding the transmission time of all interferers together, the model can obtain the expected total interference time by properly combining the transmission time of all individual nodes along with the time when two or more nodes transmit simultaneously. Through dividing the interferers into groups according to the strength levels of their received interference power at the interested node, less significant interfering signals can be ignored to reduce the complexity when investigating real scenarios. The model provides an approach to a new detection method for jamming attacks in wireless networks based on a criterion with combined operations of ECU and CU. In the experiments, we find a strong connection between ECU and the received interference power and time. In many cases, strong and frequent interference is accompanied by a declination of ECU. The descending slope though may be steep or flat. When the decrease of ECU is not significant, CU can be observed with a sharp drop instead. Therefore, the two metrics, ECU and CU when properly combined together, demonstrate to be an effective measurement for judging strong interference. In addition, relating to other jamming detection methods in the literature, we build a mathematical connection between the new jamming detection conditions and PDR, the Packet Delivery Ratio, which has been proved effective by previous researchers. Thus, the correlation between the new criteria and PDR guarantees the validity of the former by relating itself to a tested mechanism. Both the ECU model and the jamming detection method are thoroughly verified with OPNET through simulation scenarios. The experiment scenarios are depicted with configuration data and collected statistical results. Especially, the radio jamming detection experiments simulate a dynamic radio channel allocation (RCA) module with a user-friendly graphical interface, through which the interference, the jamming state, and the channel switching process can be monitored. The model can further be applied to other applications such as global performance optimization based on the total ECU of all nodes in a wireless communications environment because ECU relates one node's transmission as the interference for others using the same channel for its global attribute, which is our work planned for the next step. We would also like to compare its effectiveness with other jamming detection methods by exploring more extensive experiment research.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Ng_fsu_0071E_14083
Format: Thesis

Title: Manipulation of Potential Energy Surfaces of Binuclear Platinum Complexes and Their Application as Viscosity Sensor.
Creator: Zhou, Chenkun, Ma, Biwu, Hallinan, Daniel T., Ramakrishnan, Subramanian, Florida State University, College of Engineering, Department of Chemical and Biomedical Engineering
Abstract/Description: Photoinduced structural change (PSC) is a fundamental excited-state dynamic process in chemical and biological systems, e.g. photoinduced flattening distortion of Cu(II) complexes1, PSCs of binuclear Pt (II) complexes2, 3. This process is highly dependent on the configuration of molecular excited-state potential energy surfaces (PESs). However, due to the lack of guidelines and approaches for designing excited-state PESs, precise manipulation of PSC processes is still very challenging. In...
Show morePhotoinduced structural change (PSC) is a fundamental excited-state dynamic process in chemical and biological systems, e.g. photoinduced flattening distortion of Cu(II) complexes1, PSCs of binuclear Pt (II) complexes2, 3. This process is highly dependent on the configuration of molecular excited-state potential energy surfaces (PESs). However, due to the lack of guidelines and approaches for designing excited-state PESs, precise manipulation of PSC processes is still very challenging. In this project, a series of rationally designed butterfly-like phosphorescent binuclear platinum complexes were synthesized with well-controlled PESs and tunable dual emissions at room temperature. We demonstrated our capability to manipulate PESs in two ways. First, we introduce the steric bulkiness effect of both cyclometalated ligands and pyrazolate bridging ligands to control the transition energy barrier of PSC process. Based on the Bell-Evans-Polanyi principle, which describe a chemical reaction between two energy minima on the first triplet excited-state PES, we reveal a simple method to engineer the dual emission of molecular systems by manipulating PES and therefore PSC to achieve desired molecular properties. Second, we synthetically control the electronic structure of the cyclometallating ligand and the steric bulkiness of the pyrazolate bridging ligand at the same time to realize the precise manipulation of the PESs. Color tuning of dual emission from blue/red, to green/red and red/deep red have been achieved for these phosphorescent molecular butterflies, which have two well-controlled energy minima on the PESs. The environmentally dependent photoluminescence of these molecular butterflies enabled their application as self-referenced luminescent viscosity sensor.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Zhou_fsu_0071N_13904
Format: Thesis

Title: Leg Specialization Control: Deriving Control from the Perspective of Limb Function.
Creator: Carbiener, Charles P., Clark, Jonathan E., Ordonez, Camilo, Xu, Chengying, Collins, Emmanuel G., Florida State University, College of Engineering, Department of Mechanical...
Show moreCarbiener, Charles P., Clark, Jonathan E., Ordonez, Camilo, Xu, Chengying, Collins, Emmanuel G., Florida State University, College of Engineering, Department of Mechanical Engineering
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Abstract/Description: Many leg controllers and gaits have been designed directly with lower level parameters. This approach can lead to very high performance gaits, but can also lead to platforms highly tuned for one particular application with drastically reduced performance elsewhere. Through the Leg Specialization (LSC) gait strategy presented here, an alternative approach is demonstrated. Designing controllers from the perspective of limb function allows for adaptation to various environments, and here has...
Show moreMany leg controllers and gaits have been designed directly with lower level parameters. This approach can lead to very high performance gaits, but can also lead to platforms highly tuned for one particular application with drastically reduced performance elsewhere. Through the Leg Specialization (LSC) gait strategy presented here, an alternative approach is demonstrated. Designing controllers from the perspective of limb function allows for adaptation to various environments, and here has produced a high performing gait capable of running on a variety of surfaces.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Carbiener_fsu_0071N_13986
Format: Thesis

Title: Open-Source Low-Cost Internet of Things Platform for Buildings.
Creator: Liu, Xiaorui, Arghandeh, Reza, Foo, Simon Y., Li, Hui, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: Internet of Things (IOT) systems are becoming a popular concept of every smart system. Many people intend to develop various IOT systems which could be smart socket can be controlled remotely and tracking the electricity consumption to save energy or a security system for home which combines several sensors and cover a big area. The goal of this thesis was to introduce a method to construct an IOT system that can monitor different parameters. The design of this project also focused on...
Show moreInternet of Things (IOT) systems are becoming a popular concept of every smart system. Many people intend to develop various IOT systems which could be smart socket can be controlled remotely and tracking the electricity consumption to save energy or a security system for home which combines several sensors and cover a big area. The goal of this thesis was to introduce a method to construct an IOT system that can monitor different parameters. The design of this project also focused on wireless interaction in order to make the system more perceptual. The design of the system was modified several times which include a changing from using Ethernet to Wi-Fi. Ultimately, it provides an effective method for monitoring a building system which could be the temperature, humidity, photo intensity, or the movement of objects, etc. The final design fulfills the fundamental goals and there is a visualization web page for the IOT system which both includes a real time data monitoring and a real time charting. This thesis will give a thorough overview of how to build an own IOT system.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Liu_fsu_0071N_14126
Format: Thesis

Title: Removal of Powdered Activated Carbon by Cloth Tertiary Filters.
Creator: Madden, Brandon Cale, Ahmad, Hafiz, Chen, Gang, Tang, Youneng, Florida State University, College of Engineering, Department of Civil and Environmental Engineering
Abstract/Description: Water conservation, wastewater treatment regulations, and the use of reclaimed/reuse water supplies have been on a collision course since society’s demand began outstripping the supply of fresh water. As potable water demand has risen, engineers have looked toward Waste Water Treatment Plants (WWTP) to alleviate the stress placed upon aquifers and surface water sources. Direct Potable Reuse (DPR), Indirect Potable Reuse (IPR) and Reuse/Reclaimed systems all conserve water; however, they also...
Show moreWater conservation, wastewater treatment regulations, and the use of reclaimed/reuse water supplies have been on a collision course since society’s demand began outstripping the supply of fresh water. As potable water demand has risen, engineers have looked toward Waste Water Treatment Plants (WWTP) to alleviate the stress placed upon aquifers and surface water sources. Direct Potable Reuse (DPR), Indirect Potable Reuse (IPR) and Reuse/Reclaimed systems all conserve water; however, they also unintentionally conserve pollutants. The widespread use of WWTP effluent conservation requires additional treatment options such as Activated Carbon treatment to further treat plant effluent. Powdered Activated Carbon (PAC) has shown promise as a treatment method to reduce pollutants but challenges remain in effectively applying PAC to a wastewater stream. Of particular concern is the application of PAC to existing facilities in which the existing hydraulic profile does not allow the use of large sedimentation tanks normally associated with PAC use in potable water applications. Cloth Media Filtration (CMF) is an existing treatment process that has seen significant saturation into the WWTP market in the United States since being introduced in 1991. While mostly targeted at tertiary treatment, alternate processes such as primary filtration and storm water treatment are now being pursued. It is suspected that CMF will capture and retain Powdered Activated Carbon (PAC) in which the two processes could be combined in order to produce an energy friendly and cost competitive approach to pollutant reductions. This research examines the feasibility of application of PAC into existing hydraulic profiles by using inline injection and its quick removal by Cloth Media Filtration (CMF). One of the most challenging aspects of PAC usage is its removal, which can be facilitated by a commercial CMF. A bench sized cloth media filter was constructed and then operated in a side stream manner with a real-world wastewater treatment train. The results show excellent performance of the designed CMF. The removal of two commercially available PACs was more than 70% within a short time using the existing hydraulic conditions of the plant. Additionally, using the backwash rates and solids removal rates, it was determined that CMF performs as an acceptable means of removal for PAC in a WWTP.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Madden_fsu_0071N_14114
Format: Thesis

Title: Experimental Study of Controlled Surface Imperfection Effects on Vortex Asymmetry of Conical Bodies at High Angles of Incidence.
Creator: Rodriguez, Joseph, Kumar, Rajan (Professor of Mechanical Engineering), Oates, William, Shoele, Kourosh, Florida State University, College of Engineering, Department of...
Show moreRodriguez, Joseph, Kumar, Rajan (Professor of Mechanical Engineering), Oates, William, Shoele, Kourosh, Florida State University, College of Engineering, Department of Mechanical Engineering
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Abstract/Description: At high angles of attack, asymmetric vortices are formed on the leeward side of flight vehicles with pointed forebodies due to the random surface imperfections near the forebody apex. These vortices induce adverse side forces and yaw moments. The forces generated are too large to be controlled using conventional control surfaces and can result in flight instability and loss of control. Although many studies have reported that random surface imperfections trigger vortex asymmetry, there is a...
Show moreAt high angles of attack, asymmetric vortices are formed on the leeward side of flight vehicles with pointed forebodies due to the random surface imperfections near the forebody apex. These vortices induce adverse side forces and yaw moments. The forces generated are too large to be controlled using conventional control surfaces and can result in flight instability and loss of control. Although many studies have reported that random surface imperfections trigger vortex asymmetry, there is a lack of understanding of how these imperfections directly correlate to the varying side force with roll orientation. The present study is aimed at gaining a better insight into the underlying flow physics of vortex asymmetry. This is accomplished by performing flow field measurements using Particle Image Velocimetry and force measurements using a six-component strain gage balance on an unpolished and a highly-polished 12° semi-apex angle cone at subsonic speeds. Measurements were carried out with and without the implementation of controlled surface imperfections. All experiments were performed at a fixed Reynolds number of 0.3 × 10^6 based on the base diameter of the cone model. The force measurements indicate that the vortices caused by the random surface imperfections are highly dependent on the magnitude of surface roughness. The results show that the side force was significantly reduced and was relatively less dependent on roll orientation for the polished cone. Flow field results show that the ratio of imperfection height to the local cross-flow boundary layer thickness was observed to be critical in influencing the vortex location and growth. Furthermore, the region of incipient boundary layer separation was highly sensitive to the controlled imperfections.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Rodriguez_fsu_0071N_14107
Format: Thesis

Title: Motion Planning Testing Environment for Robotic Skid-Steered Vehicles.
Creator: Pace, James, Collins, Emmanuel G., Clark, Jonathan E., Ordonez, Camilo, Shoele, Kourosh, Florida State University, College of Engineering, Department of Mechanical Engineering
Abstract/Description: One of the main goals of robotics research is to give physical platforms intelligence, allowing for the platforms to act autonomously with minimal direction from humans. Motion planning is the process by which a mobile robot plans a trajectory that moves the robot from one state to another. While there are many motion planning algorithms, this research focuses on Sampling Based Model Predictive Optimization (SBMPO), a motion planning algorithm that allows for the generation of trajectories...
Show moreOne of the main goals of robotics research is to give physical platforms intelligence, allowing for the platforms to act autonomously with minimal direction from humans. Motion planning is the process by which a mobile robot plans a trajectory that moves the robot from one state to another. While there are many motion planning algorithms, this research focuses on Sampling Based Model Predictive Optimization (SBMPO), a motion planning algorithm that allows for the generation of trajectories that are not only dynamically feasible, but also efficient in terms of a user defined cost function (specifically in this research, distance traveled or energy consumed). To accomplish this, SBMPO uses the kinematic, dynamic, and power models of the robot. The kinematic, dynamic, and power models of a skid-steered robot are dependent on the type and inclination of the terrain over which the robot is traversing. Previous research has successfully used SBMPO to plan trajectories on different inclinations and terrain types, but with the terrain type and inclination being held constant over the trajectory. This research extends the prior work to plan trajectories where the terrain type changes over the trajectory and where the robot has the option to go over or around hills, situations extremely common in real world environments encountered in military and search and rescue operations. Furthermore, this research documents the design and implementation of a 3D visualization environment which allows for the visualization of the trajectory generated by the planner without having a robot follow the trajectory in a physical environment.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Pace_fsu_0071N_14099
Format: Thesis

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