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Description
A framework to obtain the failure surface of a unidirectional composite which can be used as an input for Generalized Tabulated Failure Criterion in MAT_213 – an orthotropic elasto-plastic material model implemented in LS-DYNA, a commercial finite element program, is discussed in this research. A finite element model consisting of

A framework to obtain the failure surface of a unidirectional composite which can be used as an input for Generalized Tabulated Failure Criterion in MAT_213 – an orthotropic elasto-plastic material model implemented in LS-DYNA, a commercial finite element program, is discussed in this research. A finite element model consisting of the fiber and the matrix is generated using the Virtual Testing Software System (VTSS) developed at Arizona State University (ASU). The framework is illustrated using the T800-F3900 unidirectional composite material manufactured by Toray Composites. The T800S fiber is modeled using MAT_213. The F3900 matrix phase is modeled using MAT_187-SAMP1. The response of the virtual tests in 1-direction tension, 1-direction compression, 2-direction tension, 2-direction compression and 2-1 plane shear are verified against the results obtained from experiments performed under quasi-static and room temperature conditions (QS-RT). Finally, a roadmap to generate the failure surface using virtual test is proposed.
ContributorsParakhiya, Yatin (Author) / Rajan, Subramaniam D. (Thesis advisor) / Mobahser, Barzin (Committee member) / Hoover, Christian (Committee member) / Arizona State University (Publisher)
Created2020
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Description
The manufacturing process for electronic systems involves many players, from chip/board design and fabrication to firmware design and installation.

In today's global supply chain, any of these steps are prone to interference from rogue players, creating a security risk.

Manufactured devices need to be verified to perform only their intended

The manufacturing process for electronic systems involves many players, from chip/board design and fabrication to firmware design and installation.

In today's global supply chain, any of these steps are prone to interference from rogue players, creating a security risk.

Manufactured devices need to be verified to perform only their intended operations since it is not economically feasible to control the supply chain and use only trusted facilities.

It is becoming increasingly necessary to trust but verify the received devices both at production and in the field.

Unauthorized hardware or firmware modifications, known as Trojans,

can steal information, drain the battery, or damage battery-driven embedded systems and lightweight Internet of Things (IoT) devices.

Since Trojans may be triggered in the field at an unknown instance,

it is essential to detect their presence at run-time.

However, it isn't easy to run sophisticated detection algorithms on these devices

due to limited computational power and energy, and in some cases, lack of accessibility.

Since finding a trusted sample is infeasible in general, the proposed technique is based on self-referencing to remove any effect of environmental or device-to-device variations in the frequency domain.

In particular, the self-referencing is achieved by exploiting the band-limited nature of Trojan activity using signal detection theory.

When the device enters the test mode, a predefined test application is run on the device

repetitively for a known period. The periodicity ensures that the spectral electromagnetic power of the test application concentrates at known frequencies, leaving the remaining frequencies within the operating bandwidth at the noise level. Any deviations from the noise level for these unoccupied frequency locations indicate the presence of unknown (unauthorized) activity. Hence, the malicious activity can differentiate without using a golden reference or any knowledge of the Trojan activity attributes.

The proposed technique's effectiveness is demonstrated through experiments with collecting and processing side-channel signals, such as involuntarily electromagnetic emissions and power consumption, of a wearable electronics prototype and commercial system-on-chip under a variety of practical scenarios.
ContributorsKarabacak, Fatih (Author) / Ozev, Sule (Thesis advisor) / Ogras, Umit Y. (Thesis advisor) / Christen, Jennifer Blain (Committee member) / Kitchen, Jennifer (Committee member) / Arizona State University (Publisher)
Created2020
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Description
This graduate thesis explains and discusses the background, methods, limitations, and future work of developing a low-budget, variable-length, Arduino-based robotics professional development program (PDP) for middle school or high school classrooms. This graduate thesis builds on prior undergraduate thesis work and conclusions. The main conclusions from the undergraduate thesis work

This graduate thesis explains and discusses the background, methods, limitations, and future work of developing a low-budget, variable-length, Arduino-based robotics professional development program (PDP) for middle school or high school classrooms. This graduate thesis builds on prior undergraduate thesis work and conclusions. The main conclusions from the undergraduate thesis work focused on reaching a larger teacher population along with providing a more robust robot design and construction. The end goal of this graduate thesis is to develop a PDP that reaches multiple teachers, involves a more robust robot design, and lasts beyond this developmental year. There have been many similar research studies and PDPs that have been tested and analyzed but do not fit the requirements of this graduate thesis. These programs provide some guidance in the creation of a new PDP. The overall method of the graduate thesis comes in four main phases: 1) setup, 2) pre-PDP phase, 3) PDP phase, and 4) post PDP phase. The setup focused primarily on funding, IRB approval, research, timeline development, and research question creation. The pre-PDP phase focused primarily on the development of new tailored-to-teacher content, a more robust robot design, and recruitment of participants. The PDP phase primarily focused on how the teachers perform and participate in the PDP. Lastly, the post PDP phase involved data analysis along with a resource development plan. The last post-PDP step is to consolidate all of the findings in a clear, concise, and coherent format for future work.
Contributorslerner, jonah (Author) / Carberry, Adam (Thesis advisor) / Walters, Molina (Committee member) / Jordan, Shawn (Committee member) / Arizona State University (Publisher)
Created2020
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Description
The presence of huge amounts of waste heat and the constant demand for electric energy makes this an appreciable research topic, yet at present there is no commercially viable technology to harness the inherent energy resource provided by the temperature differential between the inside and outside of buildings. In a

The presence of huge amounts of waste heat and the constant demand for electric energy makes this an appreciable research topic, yet at present there is no commercially viable technology to harness the inherent energy resource provided by the temperature differential between the inside and outside of buildings. In a newly developed technology, electricity is generated from the temperature gradient between building walls through a Seebeck effect. A 3D-printed triply periodic minimal surface (TPMS) structure is sandwiched in copper electrodes with copper (I) sulphate (Cu2SO4) electrolyte to mimic a thermogalvanic cell. Previous studies mainly concentrated on mechanical properties and the electric power generation ability of these structures; however, the goal of this study is to estimate the thermal resistance of the 3D-printed TPMS experimentally. This investigation elucidates their thermal resistances which in turn helps to appreciate the power output associated in the thermogalvanic structure. Schwarz P, Gyroid, IWP, and Split P geometries were considered for the experiment with electrolyte in the thermogalvanic brick. Among these TPMS structures, Split P was found more thermally resistive than the others with a thermal resistance of 0.012 m2 K W-1. The thermal resistances of Schwarz D and Gyroid structures were also assessed experimentally without electrolyte and the results are compared to numerical predictions in a previous Mater's thesis.
ContributorsDasinor, Emmanuel (Author) / Phelan, Patrick (Thesis advisor) / Milcarek, Ryan (Committee member) / Bhate, Dhruv (Committee member) / Arizona State University (Publisher)
Created2020
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Description
The problem of modeling and controlling the distribution of a multi-agent system has recently evolved into an interdisciplinary effort. When the agent population is very large, i.e., at least on the order of hundreds of agents, it is important that techniques for analyzing and controlling the system scale well with

The problem of modeling and controlling the distribution of a multi-agent system has recently evolved into an interdisciplinary effort. When the agent population is very large, i.e., at least on the order of hundreds of agents, it is important that techniques for analyzing and controlling the system scale well with the number of agents. One scalable approach to characterizing the behavior of a multi-agent system is possible when the agents' states evolve over time according to a Markov process. In this case, the density of agents over space and time is governed by a set of difference or differential equations known as a {\it mean-field model}, whose parameters determine the stochastic control policies of the individual agents. These models often have the advantage of being easier to analyze than the individual agent dynamics. Mean-field models have been used to describe the behavior of chemical reaction networks, biological collectives such as social insect colonies, and more recently, swarms of robots that, like natural swarms, consist of hundreds or thousands of agents that are individually limited in capability but can coordinate to achieve a particular collective goal.

This dissertation presents a control-theoretic analysis of mean-field models for which the agent dynamics are governed by either a continuous-time Markov chain on an arbitrary state space, or a discrete-time Markov chain on a continuous state space. Three main problems are investigated. First, the problem of stabilization is addressed, that is, the design of transition probabilities/rates of the Markov process (the agent control parameters) that make a target distribution, satisfying certain conditions, invariant. Such a control approach could be used to achieve desired multi-agent distributions for spatial coverage and task allocation. However, the convergence of the multi-agent distribution to the designed equilibrium does not imply the convergence of the individual agents to fixed states. To prevent the agents from continuing to transition between states once the target distribution is reached, and thus potentially waste energy, the second problem addressed within this dissertation is the construction of feedback control laws that prevent agents from transitioning once the equilibrium distribution is reached. The third problem addressed is the computation of optimized transition probabilities/rates that maximize the speed at which the system converges to the target distribution.
ContributorsBiswal, Shiba (Author) / Berman, Spring (Thesis advisor) / Fainekos, Georgios (Committee member) / Lanchier, Nicolas (Committee member) / Mignolet, Marc (Committee member) / Peet, Matthew (Committee member) / Arizona State University (Publisher)
Created2020
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Description
Energy is one of the wheels on which the modern world runs. Therefore, standards and limits have been devised to maintain the stability and reliability of the power grid. This research shows a simple methodology for increasing the amount of Inverter-based Renewable Generation (IRG), which is also known as Inverter-based

Energy is one of the wheels on which the modern world runs. Therefore, standards and limits have been devised to maintain the stability and reliability of the power grid. This research shows a simple methodology for increasing the amount of Inverter-based Renewable Generation (IRG), which is also known as Inverter-based Resources (IBR), for that considers the voltage and frequency limits specified by the Western Electricity Coordinating Council (WECC) Transmission Planning (TPL) criteria, and the tie line power flow limits between the area-under-study and its neighbors under contingency conditions. A WECC power flow and dynamic file is analyzed and modified in this research to demonstrate the performance of the methodology. GE's Positive Sequence Load Flow (PSLF) software is used to conduct this research and Python was used to analyze the output data.

The thesis explains in detail how the system with 11% of IRG operated before conducting any adjustments (addition of IRG) and what procedures were modified to make the system run correctly. The adjustments made to the dynamic models are also explained in depth to give a clearer picture of how each adjustment affects the system performance. A list of proposed IRG units along with their locations were provided by SRP, a power utility in Arizona, which were to be integrated into the power flow and dynamic files. In the process of finding the maximum IRG penetration threshold, three sensitivities were also considered, namely, momentary cessation due to low voltages, transmission vs. distribution connected solar generation, and stalling of induction motors. Finally, the thesis discusses how the system reacts to the aforementioned modifications, and how IRG penetration threshold gets adjusted with regards to the different sensitivities applied to the system.
ContributorsAlbhrani, Hashem A M H S (Author) / Pal, Anamitra (Thesis advisor) / Holbert, Keith E. (Committee member) / Ayyanar, Raja (Committee member) / Arizona State University (Publisher)
Created2020
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Description
Photocatalytic activity of titanium dioxide (titania or TiO2) offers enormous potential in solving energy and environmental problems. Immobilization of titania nanoparticles on inert substrates is an effective way of utilizing its photocatalytic activity since nanoparticles enable high mass-transport, and immobilization avoids post-treatment separation. For competitive photocatalytic performance, the morphology of

Photocatalytic activity of titanium dioxide (titania or TiO2) offers enormous potential in solving energy and environmental problems. Immobilization of titania nanoparticles on inert substrates is an effective way of utilizing its photocatalytic activity since nanoparticles enable high mass-transport, and immobilization avoids post-treatment separation. For competitive photocatalytic performance, the morphology of the substrate can be engineered to enhance mass-transport and light accessibility. In this work, two types of fiber architectures (i.e., dispersed polymer/titania phase or D-phase, and multi-phase polymer-core/composite-shell fibers or M-phase) were explored as effective substrate solutions for anchoring titania. These fibers were fabricated using a low-cost and scalable fiber spinning technique. Polymethyl methacrylate (PMMA) was selected as the substrate material due to its ultraviolet (UV) transparency and stability against oxidative radicals. The work systematically investigates the influence of the fiber porosity on mass-transport and UV light scattering. The properties of the fabricated fiber systems were characterized by scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), UV-vis spectrophotometry (UV-vis), and mechanical analysis. The photocatalytic performance was characterized by monitoring the decomposition of methylene blue (MB) under UV (i.e., 365 nm) light. Fabrication of photocatalytic support structures was observed to be an optimization problem where porosity improved mass transport but reduced UV accessibility. The D-phase fibers demonstrated the highest MB degradation rate (i.e., 0.116 min-1) due to high porosity (i.e., 33.2 m2/g). The M-phase fibers reported a better degradation rate compared to a D-phase fibers due to higher UV accessibility efficiency.
ContributorsKanth, Namrata (Author) / Song, Kenan (Thesis advisor) / Tongay, Sefaattin (Thesis advisor) / Kannan, Arunachala Mada (Committee member) / Arizona State University (Publisher)
Created2020
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Description
The popularity of solar photovoltaic (PV) energy is growing across the globe with more than 500 GW installed in 2018 with a capacity of 640 GW in 2019. Improved PV module reliability minimizes the levelized cost of energy. Studying and accelerating encapsulant browning and solder bond degradation—two of the most

The popularity of solar photovoltaic (PV) energy is growing across the globe with more than 500 GW installed in 2018 with a capacity of 640 GW in 2019. Improved PV module reliability minimizes the levelized cost of energy. Studying and accelerating encapsulant browning and solder bond degradation—two of the most commonly observed degradation modes in the field—in a lab requires replicating the stress conditions that induce the same field degradation modes in a controlled accelerated environment to reduce testing time.

Accelerated testing is vital in learning about the reliability of solar PV modules. The unique streamlined approach taken saves time and resources with a statistically significant number of samples being tested in one chamber under multiple experimental stress conditions that closely mirror field conditions that induce encapsulant browning and solder bond degradation. With short circuit current (Isc) and series resistance (Rs) degradation data sets at multiple temperatures, the activation energies (Ea) for encapsulant browning and solder bond degradation was calculated.

Regular degradation was replaced by the wear-out stages of encapsulant browning and solder bond degradation by subjecting two types of field-aged modules to further accelerated testing. For browning, the Ea calculated through the Arrhenius model was 0.37 ± 0.17 eV and 0.71 ± 0.07 eV. For solder bond degradation, the Arrhenius model was used to calculate an Ea of 0.12 ± 0.05 eV for solder with 2wt% Ag and 0.35 ± 0.04 eV for Sn60Pb40 solder.

To study the effect of types of encapsulant, backsheet, and solder on encapsulant browning and solder bond degradation, 9-cut-cell samples maximizing available data points while minimizing resources underwent accelerated tests described for modules. A ring-like browning feature was observed in samples with UV pass EVA above and UV cut EVA below the cells. The backsheet permeability influences the extent of oxygen photo-bleaching. In samples with solder bond degradation, increased bright spots and cell darkening resulted in increased Rs. Combining image processing with fluorescence imaging and electroluminescence imaging would yield great insight into the two degradation modes.
ContributorsGopalakrishna, Hamsini (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Rogers, Bradley (Committee member) / Hacke, Peter (Committee member) / Arizona State University (Publisher)
Created2020
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Description
About 20-50% of industrial processes energy is lost as waste heat in their operations. The thermal hydraulic engine relies on the thermodynamic properties of supercritical carbon dioxide (CO2) to efficiently perform work. Carbon dioxide possesses great properties that makes it a safe working fluid for the engine’s applications. This research

About 20-50% of industrial processes energy is lost as waste heat in their operations. The thermal hydraulic engine relies on the thermodynamic properties of supercritical carbon dioxide (CO2) to efficiently perform work. Carbon dioxide possesses great properties that makes it a safe working fluid for the engine’s applications. This research aims to preliminarily investigate the actual efficiency which can be obtained through experimental data and compare that to the Carnot or theoretical maximum efficiency. The actual efficiency is investigated through three approaches. However, only the efficiency results from the second method are validated since the other approaches are based on a complete actual cycle which was not achieved for the engine. The efficiency of the thermal hydraulic engine is found to be in the range of 0.5% to 2.2% based on the second method which relies on the boundary work by the piston. The heating and cooling phases of the engine’s operation are viewed on both the T-s (temperature-entropy) and p-v (pressure-volume) diagrams. The Carnot efficiency is also found to be 13.7% from a temperature difference of 46.20C based on the measured experimental data. It is recommended that the thermodynamic cycle and efficiency investigation be repeated using an improved heat exchanger design to reduce energy losses and gains during both the heating and cooling phases. The temperature of CO2 can be measured through direct contact with the thermocouple and pressure measurements can be improved using a digital pressure transducer for the thermodynamic cycle investigation.
ContributorsManford, David (Author) / Phelan, Patrick (Thesis advisor) / Calhoun, Ronald (Thesis advisor) / Shuaib, Abdelrahman (Committee member) / Arizona State University (Publisher)
Created2020
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Description
Suction stabilized floats have been implemented into a variety of applications such as supporting wind turbines in off-shore wind farms and for stabilizing cargo ships. This thesis proposes an alternative use for the technology in creating a system of suction stabilized floats equipped with real time location modules to hel

Suction stabilized floats have been implemented into a variety of applications such as supporting wind turbines in off-shore wind farms and for stabilizing cargo ships. This thesis proposes an alternative use for the technology in creating a system of suction stabilized floats equipped with real time location modules to help first responders establish a localized coordinate system to assist in rescues. The floats create a stabilized platform for each anchor module due to the inverse slack tank effect established by the inner water chamber. The design of the float has also been proven to be stable in most cases of amplitudes and frequencies ranging from 0 to 100 except for when the frequency ranges from 23 to 60 Hz for almost all values of the amplitude. The modules in the system form a coordinate grid based off the anchors that can track the location of a tag module within the range of the system using ultra-wideband communications. This method of location identification allows responders to use the system in GPS denied environments. The system can be accessed through an Android app with Bluetooth communications in close ranges or through internet of things (IoT) using a module as a listener, a Raspberry Pi and an internet source. The system has proven to identify the location of the tag in moderate ranges with an approximate accuracy of the tag location being 15 cm.
ContributorsDye, Michaela (Author) / Redkar, Sangram (Thesis advisor) / Sugar, Thomas (Committee member) / Rogers, Bradley (Committee member) / Arizona State University (Publisher)
Created2020