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Full-Text Articles in Materials Science and Engineering

The Design And Analysis Of Robust Mems Devices For Extreme Space Environments, Joshua Taggart Jan 2026

The Design And Analysis Of Robust Mems Devices For Extreme Space Environments, Joshua Taggart

Honors Undergraduate Theses

The purpose of this study is to analyze aluminum nitride (AlN) micro-electromechanical systems (MEMS) resonators designed for extreme-environment applications. The devices of study are Lamb wave, piezoelectric resonators designed and fabricated using conventional semiconductor manufacturing processes and operating around various frequencies in the megahertz range. The purpose of this study is to advance understanding of MEMS devices in extreme-temperature and radiated environments for outer-space applications.

Devices were tested under vacuum at temperatures ranging from room temperature (~21°C) to 800°C. Under these conditions, the device was measured both as a resonator and in an oscillator circuit. Results show that the resonant …


Machine Learning Modeling Of In-Situ Effective Thermal Conductivities And Ablation Behaviors Of Ceramic Matrix Composites Under Hydrogen Combustion Environments For Gas Turbine Engines, Jayanta Bhusan Deb Jan 2026

Machine Learning Modeling Of In-Situ Effective Thermal Conductivities And Ablation Behaviors Of Ceramic Matrix Composites Under Hydrogen Combustion Environments For Gas Turbine Engines, Jayanta Bhusan Deb

Graduate Studies Theses and Dissertations 2026

Through the integration of experimental characterization, machine learning, deep learning, numerical modeling, and physics-informed artificial intelligence, this dissertation explores the thermal performance of polymer-derived ceramic matrix composites (CMCs) for hydrogen combustion environments. The polymer infiltration and pyrolysis (PIP) process was used to create Yttria-stabilized zirconia (YSZ)-fiber-reinforced ceramic matrix composites, which were then experimentally assessed under hydrogen torch and hydrogen combustion conditions typical of next-generation gas turbine and aerospace propulsion systems. Front- and back-surface temperature measurements were used to continually monitor thermal reactions, and post-test microstructural characterization and numerical simulations were carried out to evaluate material integrity and heat-transfer behavior. To …


Optically-Pumped Semiconductor Optical Amplifiers, Dhruvkumar Desai Jan 2026

Optically-Pumped Semiconductor Optical Amplifiers, Dhruvkumar Desai

Graduate Studies Theses and Dissertations 2026

Semiconductor optical amplifiers (SOAs) offer a low-cost, compact solution for power amplification needs in an optical communication system compared with the dominant erbium-doped fiber amplifiers (EDFAs). They can also provide a wide gain bandwidth. However, conventional electrically-pumped SOAs suffer from larger noise figures, low saturation power, and polarization dependence, in comparison with EDFAs. We propose an optically-pumped SOA (OP-SOA) that will maintain the benefits of conventional SOAs while closing the gaps in other amplifier performance metrics. The underlying reasons for optical pumping are twofold. First, optical pumping allows higher carrier injection and thus "population inversion." Second, optical pumping decouples carrier …


Study On Fracture Toughness Under Different Modes Through Continuum Damage Mechanics Based Fracture Locus, Yeting Sun Jan 2026

Study On Fracture Toughness Under Different Modes Through Continuum Damage Mechanics Based Fracture Locus, Yeting Sun

Graduate Studies Theses and Dissertations 2026

Traditional elastic-plastic fracture mechanics (EPFM) relies on crack-tip analysis, whereas continuum damage mechanics (CDM) is typically calibrated from uncracked bodies. This dissertation aims to bridge the gap between these two fundamental branches by explicitly linking fracture toughness with ductile damage models. Based on the assumptions regarding Mode I crack deformation, analytical solutions are derived to establish a novel relationship among Mode I fracture toughness, CDM-based ductile fracture strain, and material strain hardening capability. This theoretical framework is subsequently extended to encompass Mode II and Mode III loading conditions. To validate the proposed relationships, finite element (FE) models are developed in …


Advanced Ysz/Si(B)Cn And Bnnt/Si(B)Cn Ceramics Matrix Composites For Extreme Environments In Hydrogen Combustion, Yiting Wang Jan 2026

Advanced Ysz/Si(B)Cn And Bnnt/Si(B)Cn Ceramics Matrix Composites For Extreme Environments In Hydrogen Combustion, Yiting Wang

Graduate Studies Theses and Dissertations 2026

The growing demand for carbon-neutral energy conversion has accelerated the development of hydrogen-fueled gas turbine systems, which operate at significantly higher temperatures and more chemically aggressive environments than conventional natural gas turbines. To meet these stringent requirements, ceramic matrix composite (CMC) materials consisting of yttria-stabilized zirconia (YSZ) fiber reinforced Si(B)CN ceramic matrix were developed. To further enhance in-plane heat dissipation, thermal stability, thermal shock resistance, and thermal cycling performance, a Si(B)CN/Boron Nitride Nanotubes (BNNT) nanocomposite coating was incorporated onto the YSZ/Si(B)CN composites. Microstructural characterization confirmed the formation of a continuous Si(B)CN ceramic matrix reinforced with uniformly distributed BNNTs. The resulting …


3d Printing Of A Solid-State Battery, Maurizio A. Brozzi Jan 2025

3d Printing Of A Solid-State Battery, Maurizio A. Brozzi

Honors Undergraduate Theses

Solid-state battery research has gained significant attention in recent years, as it provides a unique solution for several common issues in conventional Li-ion batteries. Additionally, as additive manufacturing technologies continue to advance, they have the potential to fabricate solid-state batteries with new materials. The objective of this study is to explore the feasibility of 3D printing of a solid-state battery. By creating an initial PEO-PSF hybrid polymer matrix dissolved in DMSO and adding a lithium salt, the base electrolyte ink was formed. With the addition of conductive additives and active material, electrode inks were also produced. Super P was used …


Synthesis And Characterization Of Multifunctional Cerium Oxide Containing Nanoparticles For Biomedical Applications, Ishaan Patel Jan 2025

Synthesis And Characterization Of Multifunctional Cerium Oxide Containing Nanoparticles For Biomedical Applications, Ishaan Patel

Honors Undergraduate Theses

This study presents the synthesis and comprehensive characterization of a novel core-shell nanoparticle composed of a maghemite (γ-Fe2O3) core and a europium-doped cerium oxide (EuCNP) shell, developed for potential use in cancer theranostics. Using a co-precipitation method, Fe2O3–EuCNP core-shell nanoparticles were synthesized and compared against control samples of CNPs, EuCNPs, and Fe2O3. A variety of characterization techniques, including UV-Vis spectroscopy, fluorescence spectroscopy, TEM, XRD, XPS, DLS, TGA, and DSC confirmed the successful synthesis of core-shell architecture and europium doping. Moreover, Fe2O3–EuCNPs demonstrating strong colloidal …


Fabricating Silver-Ceria Polymer Nanocomposite Scaffolds For Biomedical Therapeutic Applications, Shreya S. Pawar Jan 2025

Fabricating Silver-Ceria Polymer Nanocomposite Scaffolds For Biomedical Therapeutic Applications, Shreya S. Pawar

Honors Undergraduate Theses

Improper healing of bone fractures and limited regeneration of bone following bone tumor resection remain a prevalent complication worldwide. Long-term effects of this include joint instability, limited movement, and arthritis. Bone infections (osteomyelitis), reactive oxygen species (ROS) generation via excessive inflammation, and underlying conditions such as osteoporosis can contribute to suboptimal bone tissue regeneration. ROS accumulation stimulates osteoblast apoptosis, while promoting osteoclast differentiation. These processes inhibit mineralization and osteogenesis. Conventional therapeutics involve the utilization of drugs and bone grafts. However, these approaches pose limitations and can result in subsequent complications. Microbial infections, ROS accumulation, and excessive inflammations are factors that …


Effect Of Metal Ions On The Reactive Oxygen Species Scavenging Capabilities Of Cerium Oxide For Biological Applications, Agastya Mittal Jan 2025

Effect Of Metal Ions On The Reactive Oxygen Species Scavenging Capabilities Of Cerium Oxide For Biological Applications, Agastya Mittal

Honors Undergraduate Theses

Ceria nanoparticles' capabilities to defend cells against oxidative stress through superoxide dismutase activity are well-documented. Ceria nanoparticles demonstrate a ratio between 3+/4+ oxidative states on the surface of the particles to exhibit oxygen vacancies, a feature that allows these particles to scavenge Reactive Oxygen Species (ROS) in times of Oxidative Stress. Oxidative stress arises from many wounds in the body, such as wounds in the skin, and can have significant impacts on the health of an individual. Even when receiving treatment for the skin wound, ROS can circulate from around the wound, be generated from an imbalance …


A Signal Processing And Mechanical Design Approach To Understanding Triboelectric And Piezoelectric Nanogenerators’ Output, Nicholas Rose Jan 2025

A Signal Processing And Mechanical Design Approach To Understanding Triboelectric And Piezoelectric Nanogenerators’ Output, Nicholas Rose

Honors Undergraduate Theses

Scalable energy harvesters—capable of converting motion into electrical output—provide promising solutions to increasing energy demands. This thesis was inspired by the potential biomedical applications of piezoelectric nanogenerators (PENG) and triboelectric nanogenerators (TENG). In theory, these devices could convert mechanical energy from the body into usable electricity for self-powered electronics such as pacemakers or cochlear implants. In line with this goal, this project worked to design a sustainable and biocompatible PENG; however, early devices produced inconsistent voltage. These output inconsistencies motivated an exploration of device reproducibility, but characterizing piezoelectric output signals is a particular challenge in the field. Subtle to significant …


Enhancing Scanning Tunneling Microscopy With Automation And Machine Learning, Darian Smalley Jan 2024

Enhancing Scanning Tunneling Microscopy With Automation And Machine Learning, Darian Smalley

Graduate Thesis and Dissertation 2023-2024

The scanning tunneling microscope (STM) is one of the most advanced surface science tools capable of atomic resolution imaging and atomic manipulation. Unfortunately, STM has many time-consuming bottlenecks, like probe conditioning, tip instability, and noise artificing, which causes the technique to have low experimental throughput. This dissertation describes my efforts to address these challenges through automation and machine learning. It consists of two main sections each describing four projects for a total of eight studies.

The first section details two studies on nanoscale sample fabrication and two studies on STM tip preparation. The first two studies describe the fabrication of …


Functional Verification Of Additively Manufactured Metallopolymer Structures For Structural Electronics Design, Nathan D. Singhal Jan 2024

Functional Verification Of Additively Manufactured Metallopolymer Structures For Structural Electronics Design, Nathan D. Singhal

Honors Undergraduate Theses

As an attempt to improve the overall cost-effectiveness and ease of structural electronics manufacturing, this study characterizes the mechanical and electrical responses of structures which are fabricated from a novel metallopolymer composite material by fused deposition modeling as they are subjected to quasi-static, uniaxial mechanical tension. Baseline values of tensile properties and electrical resistivity were first obtained via ASTM D638-22 standard testing procedures and linear sweep voltammetry (LSV), respectively. A hybrid procedure to measure in-situ mechanically dependent electrical behavior was subsequently developed and implemented. The mechanical and electromechanical testing was followed by the derivation of stochastic values for several mechanical …


Development Of High Current Electromigration Test System For Evaluation Of Novel Solder Structures, Nicholas Pareis Jan 2023

Development Of High Current Electromigration Test System For Evaluation Of Novel Solder Structures, Nicholas Pareis

Electronic Theses and Dissertations, 2020-2023

Electromigration reliability of ball-grid-array (BGA) solder joints is emerging as a critical area of research for advanced microelectronic devices, especially those with high power requirements. In this study, a novel high current electromigration test system, including a temperature sensing capability, was designed and developed for the purpose of performing electromigration characterization of various BGA solder joint structures, including features designed for reduced current crowding. This study consisted of two main parts: design and development of a novel high current electromigration test system, and using this novel system for electromigration characterization of BGA solder joints. In the first portion of this …


Xps Study Of Calcium Lanthanum Sulfide Ceramics, Brian E. Butkus Jan 2023

Xps Study Of Calcium Lanthanum Sulfide Ceramics, Brian E. Butkus

Graduate Thesis and Dissertation 2023-2024

Long wave infrared (LWIR) optics that transmit in the 8 to 14 m wavelength range and, additionally, can withstand severe physical and thermal stresses are needed for advanced remote sensing, guidance and communication-based applications. However, most non-oxide transparent LWIR optics do not have the wider transmission range, nor the hardness and resistance to thermal shock needed for extreme environments. Because of these limitations, research is circling back to a promising material, calcium lanthanum sulfide (CLS), that could meet LWIR needs for extreme environments.

In this thesis, we will demonstrate the abilities of x-ray photoelectron spectroscopy (XPS) as a technique for …


Functionalization Of 1d And 2d Nanostructures And Their Applications, Yuen Yee Li Sip Jan 2023

Functionalization Of 1d And 2d Nanostructures And Their Applications, Yuen Yee Li Sip

Graduate Thesis and Dissertation 2023-2024

Material discovery and development has been playing a significant role in shaping human civilizations, by studying and improving materials for appealing observations to aid in our survival as well as to satisfy our curiosity. From the common earthly materials that give us strong building structures and hunting weapons to the Silicon Age that contributes to the creation of modern electronics and computers, the development of novel and enhanced materials continues to grow. Recently, a new field has emerged that is rapidly expanding the engineering circle; these are called nanomaterials. By shrinking bulk materials into structures with nanoscale dimensions, there is …


A Thermal, Mechanical, And Materials Framework For A Shape Memory Alloy Heat Engine For Thermal Management And Energy Recovery, Maria Chikhareva Jan 2023

A Thermal, Mechanical, And Materials Framework For A Shape Memory Alloy Heat Engine For Thermal Management And Energy Recovery, Maria Chikhareva

Electronic Theses and Dissertations, 2020-2023

Shape memory alloy (SMA) heat engines possess an inherent property of sensing a change in temperature, performing work, and rejecting heat through the shape memory effect resulting from a temperature-induced phase transformation. This work presents a framework for the design and implementation of an SMA-based Stirling heat engine for maximum power or speed incorporating and combining mechanical, thermal, and material aspects. The motivation for this work comes from the growing need for reliable thermal management and energy recovery in both ground and space applications of interest to NASA and commercial space companies. In future lunar and Mars missions, an SMA …


Laser Powder Bed Fusion Of Bimetallic Structures, Asif Mahmud Jan 2023

Laser Powder Bed Fusion Of Bimetallic Structures, Asif Mahmud

Graduate Thesis and Dissertation 2023-2024

Laser powder bed fusion (LPBF) is a popular additive manufacturing (AM) technique that has demonstrated the capability to produce sophisticated engineering components. This work reports the crack-free fabrication of an SS316L/IN718 bimetallic structure via LPBF, along with compositional redistribution, phase transformations and microstructural development, and nanohardness variations. Constituent intermixing after LPBF was quantitatively estimated using thermo-kinetic coefficients of mass transport and compared with the diffusivity of Ni in the austenitic Fe-Ni system. The intermixing of primary solvents (Ni and Fe) in SS316L/IN718 bimetallic structures was observed for an intermixing zone of approximately 800 µm, and their intermixing coefficient was estimated …


Nanostructured Alloy Thin Film Fabrication And Application For Zinc-Air Battery And Lithium-Ion Battery, Guanzhi Wang Jan 2023

Nanostructured Alloy Thin Film Fabrication And Application For Zinc-Air Battery And Lithium-Ion Battery, Guanzhi Wang

Electronic Theses and Dissertations, 2020-2023

The depletion of unsustainable fossil fuels and growing environmental issues have given rise to scientific challenges and research interests in the development of renewable energy technologies to meet the rising global energy demand. Electrochemical energy storage and conversion technologies (ESCTs), such as lithium-ion batteries, metal-air batteries, supercapacitors, and fuel cells, etc., offer a clean and sustainable strategy for utilizing energy. As the core components, the electrode materials, including anodes, cathodes, and catalysts, play a direct decisive role in the device's performance in practical application. Therefore, the development of high-performance and low-cost electrode materials is critical for the success of these …


Electroanalytical Investigations Of Microrna-Conjugated Cerium Oxide Based Nanomaterials For Biomedical Applications, Chaimae El Ghzaoui Jan 2023

Electroanalytical Investigations Of Microrna-Conjugated Cerium Oxide Based Nanomaterials For Biomedical Applications, Chaimae El Ghzaoui

Electronic Theses and Dissertations, 2020-2023

Diabetes patients are increasingly suffering from wound-healing impairments coupled with other severe medical conditions. High levels of oxidative stress and proinflammatory cytokines are predominant pathologic characteristics of diabetic wounds. Applying microRNA (miRNA) in gene therapy often successfully treats various disorders by generating highly specific bio-responses. Studies revealed that microRNA146a (miR146a), a regulator of inflammation, is downregulated in diabetic wounds. However, miR203 is found to be highly-expressed in diabetic foot ulcers in positive correlation with disease severity. We have synthesized Cerium oxide nanoparticles (CNPs) since they are used in various biomedical applications due to their high enzyme-mimetic activities and reactive oxygen …


Silver Doped Nanoceria (Agcnp) Integrated Silk Scaffold For Chronic Wound Healing, Architha K. Venkatesan Jan 2023

Silver Doped Nanoceria (Agcnp) Integrated Silk Scaffold For Chronic Wound Healing, Architha K. Venkatesan

Honors Undergraduate Theses

Chronic wound healing can be seriously impeded by the formation of biofilms, infections, peri-wound edema, hematoma, osteomyelitis, and the formation of reactive oxidative species (ROS). We hypothesize that a scaffold created from Silver-Doped Nanoceria (AgCNP) embedding silk can be beneficial to aid the wound healing process, inhibit inflammation and prevent microorganisms from forming a biofilm over the wound. Current wound healing methods such as intradermal injections are not advantageous to use since they can cause unwanted responses elsewhere in the body other than the wound site. Silk, however, has a positive impact on the wound healing effect and can be …


High Voltage Aqueous Electrolyte Based Structural Supercapacitors For Electric Vehicles, Deepak Pandey Dec 2022

High Voltage Aqueous Electrolyte Based Structural Supercapacitors For Electric Vehicles, Deepak Pandey

Electronic Theses and Dissertations, 2020-2023

The current electric vehicles (EVs) face many challenges like limited charge capacity, low miles/charge, and long charging times. Herein, these issues are addressed by developing "energized composite," which is a multifunctional supercapacitor-based energy-storing carbon fiber reinforced polymer composite that can store supplemental electric energy and function as the body shell of EV's. This is achieved by developing a unique design, vertically aligning graphene sheets on carbon fiber electrodes and depositing metal oxides to obtain high energy density electrodes. A high-strength multilayer composite is fabricated using an alternate layer pattern configuration of epoxy and polyacrylamide gel electrolyte. The composite so developed …


Ceria Defect Engineering Using Thin-Films/Ald And Biological Applications, Udit Kumar Dec 2022

Ceria Defect Engineering Using Thin-Films/Ald And Biological Applications, Udit Kumar

Electronic Theses and Dissertations, 2020-2023

Ceria nanostructures have been utilized for various engineering applications due to their unique defect structure, enabling them to have regenerative redox properties. The ability to shuttle between Ce3+ and Ce4+ oxidation states extends to unique properties. Defect level in ceria is usually expressed in the Ce3+/Ce4+ ratio. It can be achieved by varying the size(0 to 3D), morphologies, dopants, hetero-nanostructures, and external stimuli. However, it is still a challenge to have precise control over defect structures in the ceria lattice. The current study aims to explore the thin film deposition techniques for cerium oxide using ALD (Atomic layer deposition) and …


High Performance And Low Cost Passivating, Carrier-Selective Contacts For Silicon Photovoltaics, Jannatul Ferdous Mousumi Dec 2022

High Performance And Low Cost Passivating, Carrier-Selective Contacts For Silicon Photovoltaics, Jannatul Ferdous Mousumi

Electronic Theses and Dissertations, 2020-2023

The world is now focusing on expanding renewable energy sources to reduce the carbon footprint and mitigate climate change. Solar energy is one of the most environment-friendly and fastest-growing renewable energy sources in the present world. While crystalline silicon (c-Si) based devices dominate the global photovoltaics (PV) market with a current share of 95%, it is still challenging to achieve the theoretical efficiency limit of 29.4% with this technology due to a few performance limiting factors. Contact recombination losses are dominant among them which result from the recombination of photo-generated charge carriers due to the presence of defects at the …


Improving The Performance And Durability Of Metal Contacts In Crystalline Silicon Solar Cells Using Advanced Characterization, Nafis Iqbal Jan 2022

Improving The Performance And Durability Of Metal Contacts In Crystalline Silicon Solar Cells Using Advanced Characterization, Nafis Iqbal

Electronic Theses and Dissertations, 2020-2023

Solar energy is one of the fastest growing forms of energy generation due to its low cost, lack of emissions, minimal maintenance, and excellent durability. However, like any other technology, it is also not free from defects and degradation, which limit its performance in the real world. Most of the degradation is related to metal contacts, which also happens to be one of the most expensive items in manufacturing, comprising almost half of the cost of converting a silicon wafer into a photovoltaic (PV) cell. Therefore, studying contact degradation to make them reliable and free of defects is the key …


Synchronous Raman Microspectroscopy And Laser Beam Induced Current Measurements As A Metrology Tool For Solar Cells And Optoelectronic Devices, Jeya Prakash Ganesan Jan 2022

Synchronous Raman Microspectroscopy And Laser Beam Induced Current Measurements As A Metrology Tool For Solar Cells And Optoelectronic Devices, Jeya Prakash Ganesan

Electronic Theses and Dissertations, 2020-2023

This works developed synchronous Raman microspectroscopy with laser beam induced current (LBIC) measurements to generate insights into structure-property correlations in finished solar cell modules. Raman spectroscopy is a powerful, non-destructive technique to examine phase and composition of materials where a laser beam excites characteristic vibrational modes of chemical bonds in a material. Conducting Raman spectroscopy under a microscope (i.e., Raman microspectroscopy) with confocal capabilities allows the chemical constituents to be mapped with high spatial resolution in the x, y and z directions. Simultaneously, the excitation laser from Raman can also generate photocarriers in a semiconductor. In a solar cell, these …


Davydov-Split Aggregates Of Cyanine Dyes For Bovine Serum Albumin Detection, Yiping Ma Jan 2022

Davydov-Split Aggregates Of Cyanine Dyes For Bovine Serum Albumin Detection, Yiping Ma

Electronic Theses and Dissertations, 2020-2023

The p-conjugated supramolecular aggregates have gained significant interest in recent years. The cyanine dye aggregates are particularly interesting due to their unique optical and excitonic properties, which cannot be found in individual molecules. Cyanine dyes can form different kinds of aggregates. H-aggregates are formed when dye molecules are packed in a face-to-face fashion, which gives rise to a blue-shift absorption band and strong emission quenching compared to the monomer. J-aggregates are composed of individual dye molecules in a head-to-tail stacking, which leads to a red-shift absorption band and a sharp intense emission band with a small Stoke shift compared with …


Influence Of Growth Parameters On The Synthesis Of Mos2 Films, Victor Okonkwo Jan 2022

Influence Of Growth Parameters On The Synthesis Of Mos2 Films, Victor Okonkwo

Honors Undergraduate Theses

Information processing is crucial in modern society, placing a great emphasis on the performance of optoelectronic devices to match ever increasing processing and memory needs. Within these devices, MoS2 has demonstrated great potential as transistors due to its enhanced electrostatic control. As increased layer thickness of quality MoS2 films have been shown to boost the performance of its transistors, growth parameters for the synthesis of ideally uniform and large area multilayered films via chemical vapor deposition were investigated. By increasing the flow pressure in the system and the growth time, increasing levels of thickness and nucleation density was …


Engineering The Electrode Properties For Developing High Performance Supercapacitors, Kowsik Sambath Kumar Jan 2022

Engineering The Electrode Properties For Developing High Performance Supercapacitors, Kowsik Sambath Kumar

Electronic Theses and Dissertations, 2020-2023

Rising global warming concern demands the need for a rapid transition to renewable energy sources. The intermittent nature of these sources emphasizes the requirement of developing highly efficient electrochemical energy storage devices like supercapacitors and batteries. Supercapacitors are at the forefront of powering various devices spanning from electric cars to aircraft. Here, we have engineered the electrode material properties for developing supercapacitors with high capacitance, energy density and cycle life. Among the electrode materials, we have focused on improving the energy storage performance of 2D materials like graphene oxide (GO) and tungsten disulfide (WS2), in addition to metal oxides such …


Processing-Microstructure-Property Correlation For 316l Stainless Steel Manufactured By Laser Powder Bed Fusion, Nathalia Diaz Vallejo Jan 2022

Processing-Microstructure-Property Correlation For 316l Stainless Steel Manufactured By Laser Powder Bed Fusion, Nathalia Diaz Vallejo

Electronic Theses and Dissertations, 2020-2023

The microstructural development of 316L stainless steel (316L SS) was investigated over a wide range of systematically varied laser powder bed fusion (LPBF) parameters, such as laser power, laser scan speed, hatch distance, and volumetric energy density. The use of volumetric energy density between 46 and 127 J/mm3 produced samples with relative density above 99.8% demonstrating that even in the optimized range of processing parameters the pores are unavoidable. Shifting from this range through a variation of laser scan speed produced two types of flaws, lack of fusion (LoF) and keyhole (KH) porosity leading to a decrease in the relative …


From Field To Failure: Detecting And Understanding Reliability Defects In Crystalline Silicon Photovoltaics, Dylan Colvin Jan 2022

From Field To Failure: Detecting And Understanding Reliability Defects In Crystalline Silicon Photovoltaics, Dylan Colvin

Electronic Theses and Dissertations, 2020-2023

Severe pollution levels and the growing influence of climate change have shown that dirty energy sources need renewable and sustainable replacements. The field of photovoltaics (PV) has grown substantially over the years from a niche space solar market to a commodity in large part due to improvements in reliability. Reliability of all materials in a PV module must be considered. The industry has seen an explosion of innovation in cell interconnection technologies with significant market penetration in the past several years. These emerging, less mature technologies require more reliability information to guide improvements. Degradation studies of long-term outdoor exposure and …