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The objective of this research was to develop Aluminophosphate-five (AlPO4-5, AFI) zeolite adsorbents for efficient oxygen removal from a process stream to support an on-going Department of Energy (DOE) project on solar energy storage. A molecular simulation study predicted that substituted AlPO4-5 zeolite can adsorb O2 through a weak chemical

The objective of this research was to develop Aluminophosphate-five (AlPO4-5, AFI) zeolite adsorbents for efficient oxygen removal from a process stream to support an on-going Department of Energy (DOE) project on solar energy storage. A molecular simulation study predicted that substituted AlPO4-5 zeolite can adsorb O2 through a weak chemical bond at ambient temperature. Substituted AlPO4-5 zeolite was successfully synthesized via hydrothermal crystallization by following carefully designed procedures to tailor the zeolite for efficient O2 adsorption. Synthesized AlPO4-5 in this work included Sn/AlPO-5, Mo/AlPO-5, Pd/AlPO-5, Si/AlPO-5, Mn/AlPO-5, Ce/AlPO-5, Fe/AlPO-5, CuCe/AlPO-5, and MnSnSi/AlPO-5. While not all zeolite samples synthesized were fully characterized, selected zeolite samples were characterized by powder x-ray diffraction (XRD) for crystal structure confirmation and phase identification, and nitrogen adsorption for their pore textural properties. The Brunauer-Emmett-Teller (BET) specific surface area and pore size distribution were between 172 m2 /g - 306 m2 /g and 6Å - 9Å, respectively, for most of the zeolites synthesized. Samples of great interest to this project such as Sn/AlPO-5, Mo/AlPO-5 and MnSnSi/AlPO-5 were also characterized using x-ray photoelectron spectroscopy (XPS) and energy-dispersive x-ray spectroscopy (EDS) for elemental analysis, scanning electron microscopy (SEM) for morphology and particle size estimation, and electron paramagnetic resonance (EPR) for nature of adsorbed oxygen. Oxygen and nitrogen adsorption experiments were carried out in a 3-Flex adsorption apparatus (Micrometrics) at various temperatures (primarily at 25℃) to determine the adsorption properties of these zeolite samples as potential adsorbents for oxygen/nitrogen separation. Experiments showed that some of the zeolite samples adsorb little-to-no oxygen and nitrogen at 25℃, while other zeolites such as Sn/AlPO-5, Mo/AlPO-5, and MnSnSi/AlPO-5 adsorb decent but inconsistent amounts of oxygen with the highest observed values of about 0.47 mmol/ g, 0.56 mmol/g, and 0.84 mmol/ g respectively. The inconsistency in adsorption is currently attributed to non-uniform doping of the zeolites, and these findings validate that some substituted AlPO4-5 zeolites are promising adsorbents. However, more investigations are needed to verify the causes of this inconsistency to develop a successful AlPO4-5 zeolite-based adsorbent for oxygen/nitrogen separation.
ContributorsBuyinza, Allan Smith (Author) / Deng, Shuguang (Thesis advisor) / Varman, Arul M (Committee member) / Jin, Kailong (Committee member) / Arizona State University (Publisher)
Created2021
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Description
Atmospheric water extraction (AWE) is an emerging technology to tackle water resource shortage challenges. One such approach to provide fresh water utilizes stimuli-responsive hydrogel-based desiccants to capture the moisture from the air and release it into the liquid form. Typical gel desiccants are composed of a hygroscopic agent for capturing

Atmospheric water extraction (AWE) is an emerging technology to tackle water resource shortage challenges. One such approach to provide fresh water utilizes stimuli-responsive hydrogel-based desiccants to capture the moisture from the air and release it into the liquid form. Typical gel desiccants are composed of a hygroscopic agent for capturing and a hydrophilic gel matrix for storage. The desorption process can be completed by elevating the temperature above the upper or lower critical solution temperature point to initiate the volume phase transition of either thermo-responsive or photothermal types. This thesis focuses on investigating the structural effect of hydrogels on moisture uptake. Firstly, the main matrix of gel desiccant, poly(N-isopropylacrylamide) hydrogel, was optimized via tuning synthesis temperature and initial monomer concentration. Secondly, a series of hydrogel-based desiccants consisting of a hygroscopic material, vinyl imidazole, and optimized poly(N-isopropylacrylamide) gel matrix were synthesized with different network structures. The moisture uptake result showed that the gel desiccant with an interpenetrating polymeric network (IPN) resulted in the best-performing moisture capturing. The gel desiccant with the best performance will be used as a primary structural unit to evaluate the feasibility of developing a light-responsive gel desiccant to materialize light-trigger moisture desorption for AWE technology in the future.
ContributorsZhao, Xingbang (Author) / Dai, Lenore (Thesis advisor) / Westerhoff, Paul (Committee member) / Jiao, Yang (Committee member) / Arizona State University (Publisher)
Created2021
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Description
Tin (Sn) has a high-specific capacity (993 mAhg-1) as an anode material for Li-ion batteries. To overcome the poor cycling performance issue caused by its large volume expansion and pulverization during the charging and discharging process, many researchers put efforts into it. Most of the strategies are through nanostructured material

Tin (Sn) has a high-specific capacity (993 mAhg-1) as an anode material for Li-ion batteries. To overcome the poor cycling performance issue caused by its large volume expansion and pulverization during the charging and discharging process, many researchers put efforts into it. Most of the strategies are through nanostructured material design and introducing conductive polymer binders that serve as matrix of the active material in anode. This thesis aims for developing a novel method for preparing the anode to improve the capacity retention rate. This would require the anode to have high electrical conductivity, high ionic conductivity, and good mechanical properties, especially elasticity. Here the incorporation of a conducting polymer and a conductive hydrogel in Sn-based anodes using a one-step electrochemical deposition via a 3-electrode cell method is reported: the Sn particles and conductive component can be electrochemically synthesized and simultaneously deposited into a hybrid thin film onto the working electrode directly forming the anode. A well-defined three dimensional network structure consisting of Sn nanoparticles coated by conducting polymers is achieved. Such a conductive polymer-hydrogel network has multiple advantageous features: meshporous polymeric structure can offer the pathway for lithium ion transfer between the anode and electrolyte; the continuous electrically conductive polypyrrole network, with the electrostatic interaction with elastic, porous hydrogel, poly (2-acrylamido-2-methyl-1-propanesulfonic acid-co-acrylonitrile) (PAMPS) as both the crosslinker and doping anion for polypyrrole (PPy) can decrease the volume expansion by creating porous scaffold and softening the system itself. Furthermore, by increasing the amount of PAMPS and creating an interval can improve the cycling performance, resulting in improved capacity retention about 80% after 20 cycles, compared with only 54% of that of the control sample without PAMPS. The cycle is performed under current of 0.1 C.
ContributorsGao, Tianxiang (Author) / He, Ximin (Thesis advisor) / Sieradzki, Karl (Committee member) / Chan, Candace (Committee member) / Arizona State University (Publisher)
Created2015
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Description
Combining 3D bio-printing and drug delivery are promising techniques tofabricate scaffolds with well controlled and patient-specific structures for tissue engineering. In this study, silk derivatives of bioink were developed consisting of silk fibroin and gelatin then 3D printed into scaffolds. The scaffolds would be evaluated for small molecule release, cell growth, degradation, and

Combining 3D bio-printing and drug delivery are promising techniques tofabricate scaffolds with well controlled and patient-specific structures for tissue engineering. In this study, silk derivatives of bioink were developed consisting of silk fibroin and gelatin then 3D printed into scaffolds. The scaffolds would be evaluated for small molecule release, cell growth, degradation, and morphology. Preparations and design of the scaffolds are major parts of engineering and tissue engineering. Scaffolds are designed to mimic extracellular matrix by providing structural support as well as promoting cell attachment and proliferation with minimum inflammation while degrading at a controlled rate. Scaffolds offers new potentials in medicine by aiding in the preparation of personalized and controlled release therapeutic systems.
ContributorsNg, Johnny (Author) / Rege, Kaushal (Thesis advisor) / Holloway, Julianne (Committee member) / Jin, Kailong (Committee member) / Arizona State University (Publisher)
Created2022
Description
Surface roughness has a negative impact on several failures of materials medium. It can accelerate the pitting corrosion, increase effective heat transfer and increase the rate of effective charge loss. However, the controlled surface roughness may be desirable in many situations. The automotive lead-acid battery is very sensitive to such

Surface roughness has a negative impact on several failures of materials medium. It can accelerate the pitting corrosion, increase effective heat transfer and increase the rate of effective charge loss. However, the controlled surface roughness may be desirable in many situations. The automotive lead-acid battery is very sensitive to such effects. The cast-on-strap machine has the largest effect on the surface roughness of the lead-antimony alloy in our case study. The two-point correlation function is an efficient characterization tool for two-phase heterogeneous materials. Considering the nature that the two-point correlation function is a spatial statistical function, it cannot distinguish between a two-phase material or materials with surfaces containing protrusion of distinct heights. A case study to examine its capability in quantifying surface roughness isintroduced. The possibility of applying a simulated annealing procedure to optimize using information obtained from the two-point correlation function is investigated. Outcomes show a successful surface representation, as well as optimization, that agrees with the initially proposed hypothesis.
ContributorsBasyoni, Mohamed Nasser (Author) / Jiao, Yang Prof. (Thesis advisor) / Yang, Sui Dr. (Committee member) / Zhuang, Houlong Dr. (Committee member) / Arizona State University (Publisher)
Created2022
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Description
Kinetic Inductance Detectors (KIDs) offer highly sensitive solutions for millimeter and submillimeter wave astronomy. KIDs are superconducting detectors capable of measuring photon energy and arrival time. KIDs use the change in surface impedance of the superconductor when an incident photon is absorbed and breaks Cooper pairs in the superconducting

Kinetic Inductance Detectors (KIDs) offer highly sensitive solutions for millimeter and submillimeter wave astronomy. KIDs are superconducting detectors capable of measuring photon energy and arrival time. KIDs use the change in surface impedance of the superconductor when an incident photon is absorbed and breaks Cooper pairs in the superconducting material. This occurs when KIDs use a superconducting resonator: when a photon is incident on the inductor, the photon is absorbed and inductance increases and the resonant frequency decreases. The resonator is weakly coupled to a transmission line which naturally allows for multiplexing to allow up to thousands of detectors to be read out on one transmission line. In this thesis a KID is presented to be used at submillimeter wavelengths. I optimized a polarization-sensitive aluminum absorber for future Balloon-borne Large Aperture Submillimeter Telescope (BLAST) missions. BLAST is designed to investigate polarized interstellar dust and the role of magnetic fields on star formation. As part of the effort to develop aluminum KIDs for BLAST, I investigated the optical coupling method including different feedhorn structures and a hybrid design. I present a suite of simulations calculating the absorption efficiency of the absorber. The optimized KID is a feedhorn/waveguide coupled front-illuminated detector that achieves 70% absorption over the frequency band centered at 250um.
ContributorsChamberlin, Kathryn (Author) / Mauskopf, Philip (Thesis advisor) / Trichopoulos, Georgios (Committee member) / Zeinolabedinzadeh, Saeed (Committee member) / Arizona State University (Publisher)
Created2022
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Description
Electron Paramagnetic Resonance (EPR) has facilitated great scientific advancements in many fields, like material science, engineering, medicine, biology, and health. EPR provided the ability to investigate samples on molecular level to detect chemical composition and identify harmful substances like free radicals. This thesis aims to explore current health and diagnostics

Electron Paramagnetic Resonance (EPR) has facilitated great scientific advancements in many fields, like material science, engineering, medicine, biology, and health. EPR provided the ability to investigate samples on molecular level to detect chemical composition and identify harmful substances like free radicals. This thesis aims to explore current health and diagnostics EPR research and investigate the free radical content in related paramagnetic centers. Examining paramagnetic diagnostic markers of Cancer, Sicklecell disease, oxidative stress, and food oxidation. After exploring current literature on EPR, an experiment is designed and conducted to test seven different coffee samples (Turkish coffee, Espresso Coffee, European Coffee, Ground Arabic Coffee, American Coffee, Roasted Arabic Coffee, and Green Arabic Coffee), using Bruker ELEXSYS E580 spectrometer at x-band and under both room temperature (298 K) and low temperature (106 -113 K). Several microwave powers (1, mW, 0.25 mW, 0.16 mW, 0.06 mW, 0.04 mW) and different modulation frequency (10 G, 5 G, 3 G) are used. The results revealed average g-value was 2.009, highest linewidth was 16.312. Espresso coffee had the highest concentration of radicals, and green Arabic coffee beans had the lowest. Obtained spectra showed signals of Reactive Oxygen Species (ROS) radicals; believed to be result of natural oxidation process, as well as trace amounts of Fe3+ and other transition metals impurities, likely to be naturally found in coffee or resulting from the process of coffee production.
ContributorsMaki, Husain (Author) / Newman, Nathan (Thesis advisor) / Alford, Terry (Committee member) / Chamberlin, Ralph (Committee member) / Arizona State University (Publisher)
Created2022
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Description
In the past decade, 2D materials especially transition metal dichalcogenides (TMDc), have been studied extensively for their remarkable optical and electrical properties arising from their reduced dimensionality. A new class of materials developed based on 2D TMDc that has gained great interest in recent years is Janus crystals. In contrast

In the past decade, 2D materials especially transition metal dichalcogenides (TMDc), have been studied extensively for their remarkable optical and electrical properties arising from their reduced dimensionality. A new class of materials developed based on 2D TMDc that has gained great interest in recent years is Janus crystals. In contrast to TMDc, Janus monolayer consists of two different chalcogen atomic layers between which the transition metal layer is sandwiched. This structural asymmetry causes strain buildup or a vertically oriented electric field to form within the monolayer. The presence of strain brings questions about the materials' synthesis approach, particularly when strain begins to accumulate and whether it causes defects within monolayers.The initial research demonstrated that Janus materials could be synthesized at high temperatures inside a chemical vapor deposition (CVD) furnace. Recently, a new method (selective epitaxy atomic replacement - SEAR) for plasma-based room temperature Janus crystal synthesis was proposed. In this method etching and replacing top layer chalcogen atoms of the TMDc monolayer happens with reactive hydrogen and sulfur radicals. Based on Raman and photoluminescence studies, the SEAR method produces high-quality Janus materials. Another method used to create Janus materials was the pulsed laser deposition (PLD) technique, which utilizes the interaction of sulfur/selenium plume with monolayer to replace the top chalcogen atomic layer in a single step. The goal of this analysis is to characterize microscale defects that appear in 2D Janus materials after they are synthesized using SEAR and PLD techniques. Various microscopic techniques were used for this purpose, as well as to understand the mechanism of defect formation. The main mechanism of defect formation was proposed to be strain release phenomena. Furthermore, different chalcogen atom positions within the monolayer result in different types of defects, such as the appearance of cracks or wrinkles across monolayers. In addition to investigating sample topography, Kelvin probe force microscopy (KPFM) was used to examine its electrical properties to see if the formation of defects impacts work function. Further study directions have been suggested for identifying and characterizing defects and their formation mechanism in the Janus crystals to understand their fundamental properties.
ContributorsSinha, Shantanu (Author) / Tongay, Sefaattin (Thesis advisor) / Alford, Terry (Committee member) / Yang, Sui (Committee member) / Arizona State University (Publisher)
Created2022
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Description
With the abundance of increasingly large datasets, the ability to predict the phase of high-entropy alloys (HEAs) based solely on elemental composition could become a reliable tool for the discovery of new HEAs. However, as the amount of data expands so does the computational time and resources required to train

With the abundance of increasingly large datasets, the ability to predict the phase of high-entropy alloys (HEAs) based solely on elemental composition could become a reliable tool for the discovery of new HEAs. However, as the amount of data expands so does the computational time and resources required to train predictive classical machine learning models. Quantum computers, which use quantum bits (qubits), could be the solution to overcoming these demands. Their ability to use quantum superposition and interference to perform calculations could be the key to handling large amounts of data. In this work, a hybrid quantum-classical machine learning algorithm is implemented on both quantum simulators and quantum processors to perform the supervised machine learning task. Their feasibility as a future tool for HEA discovery is evaluated based on the algorithm’s performance. An artificial neural network (ANN), run by classical computers, is also trained on the same data for performance comparison. The accuracy of the quantum-classical model was found to be comparable to the accuracy achieved by the classical ANN with a slight decrease in accuracy when ran on quantum hardware due to qubit susceptibility to decoherence. Future developments in the applied quantum machine learning method are discussed.
ContributorsBrown, Payden Lance (Author) / Zhuang, Houlong (Thesis advisor) / Ankit, Kumar (Committee member) / Jiao, Yang (Committee member) / Arizona State University (Publisher)
Created2022
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Description
Many important technologies, including electronics, computing, communications, optoelectronics, and sensing, are built on semiconductors. The band gap is a crucial factor in determining the electrical and optical properties of semiconductors. Beyond graphene, newly found two-dimensional (2D) materials have semiconducting bandgaps that range from the ultraviolet in hexagonal boron nitride to

Many important technologies, including electronics, computing, communications, optoelectronics, and sensing, are built on semiconductors. The band gap is a crucial factor in determining the electrical and optical properties of semiconductors. Beyond graphene, newly found two-dimensional (2D) materials have semiconducting bandgaps that range from the ultraviolet in hexagonal boron nitride to the terahertz and mid-infrared in bilayer graphene and black phosphorus, visible in transition metal dichalcogenides (TMDs). These 2D materials were shown to have highly controllable bandgaps which can be controlled by alloying. Only a small number of TMDs and monochalcogenides have been alloyed, though, because alloying compromised the material's Van der Waals (Vdw) property and the stability of the host crystal lattice phase. Phase transition in 2D materials is an interesting phenomenon where work has been done only on few TMDs namely MoTe2, MoS2, TaS2 etc.In order to change the band gaps and move them towards the UV (ultraviolet) and IR (infrared) regions, this work has developed new 2D alloys in InSe by alloying them with S and Te at 10% increasing concentrations. As the concentration of the chalcogens (S and Te) increased past a certain point, a structural phase transition in the alloys was observed. However, pinpointing the exact concentration for phase change and inducing phase change using external stimuli will be a thing of the future. The resulting changes in the crystal structure and band gap were characterized using some basic characterization techniques like scanning electron microscopy (SEM), X-ray Diffraction (XRD), Raman and photoluminescence spectroscopy.
ContributorsYarra, Anvesh Sai (Author) / Tongay, Sefaattin (Thesis advisor) / Yang, Sui (Committee member) / Alford, Terry (Committee member) / Arizona State University (Publisher)
Created2022