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Full-Text Articles in Engineering Science and Materials

Aqueous Fabrication Of Pristine And Oxide Coated Znse Nanoparticles, Nicholas L. Van Zandt Jan 2021

Aqueous Fabrication Of Pristine And Oxide Coated Znse Nanoparticles, Nicholas L. Van Zandt

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Semiconducting nanoparticles have received significant attention due to their unique optoelectronic properties. Quantum dots (QDs), a class of spherical nanoparticles, possess a size-dependent bandgap and photoluminescence at visible wavelengths. QDs have many applications including biological labelling, solar cells, chemical impurity detection, and optical glasses. Doping QDs into optical glasses is highly desirable. High-quality QDs can be synthesized via liquid solution methods. However, solution-synthesized QDs often degrade over time and they cannot survive incorporation into a glass melt without protection. In this work, the aqueous synthesis of ZnSe QDs and coating with nanometer silica and alumina protective shells are investigated. The …


Fabrication And Analysis Of High-Performance Thermochemically Densified Wood, Victor Arulappan Pushparaj Jan 2021

Fabrication And Analysis Of High-Performance Thermochemically Densified Wood, Victor Arulappan Pushparaj

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While wood construction may be as ancient as humanity itself, wood remains one of the most utilized structural materials because of it’s availability, low cost, durability, surprisingly high specific mechanical properties, and renewability. Recent research into wood-based materials has focused on strategies for enhancing the strength and stiffness of as-grown materials. We fabricated densified wood by thermochemically treating raw white oak wood in Na2SO3 and NaOH solutions, followed by compressing the treated wood at 5MPa at high temperature. Treating the raw wood in NaOH and Na2SO3 cleaves the alpha-O-4 ether bond and beta-O-4 ether bonds, thus dissolving most of the …


Functionalizing Ceramic Matrix Composites By The Integration Of A Metallic Substructure With Comparable Feature Size, Elizabeth Pierce Heckman Jan 2021

Functionalizing Ceramic Matrix Composites By The Integration Of A Metallic Substructure With Comparable Feature Size, Elizabeth Pierce Heckman

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A metallic network has been embedded in a silicon carbide fiber– silicon carbide (SiC) matrix ceramic composite (CMC) in order to combine the functional properties of the metal and the structural properties of the CMC. The processing of the composite involves iterative pre-ceramic polymer infiltration and heating to temperatures at 1100°C. The metallic structure embedded in the CMC must retain its unique properties during processing and cannot convert to a silicide or carbide resulting from diffusion of Si and C species from the SiC matrix. To gain an understanding of the diffusion process, a fully processed CMC with tungsten, tantalum, …


Ab Initio Methylammonium Orientation And Monolayer Effects In Hybrid Perovskite Solar Cells, Jacob M. Artz Jan 2021

Ab Initio Methylammonium Orientation And Monolayer Effects In Hybrid Perovskite Solar Cells, Jacob M. Artz

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Methylammonium lead triiodide (MAPbI3) has garnered attention due to their high solar cell efficiencies and low cost to manufacture, but commercialization is not yet possible owing to poor environmental stability. Thus, researchers seek ways which optimize the performance of the MAPbI3 solar cell by modifying the architecture and through interfacial engineering of the charge transport layers. Difficulties in understanding these devices arise from ion migration, charge separation and recombination, and metastable, thermally active precessions of the methylammonium (MA) moiety in the lead iodide framework. In this work, focus is given to the perovskite and an adsorbed monolayer, 2,3,4,5,6-pentafluorothiophenol (C6F5SH), which …


Ab Initio Methylammonium Orientation And Monolayer Effects In Hybrid Perovskite Solar Cells, Jacob M. Artz Jan 2021

Ab Initio Methylammonium Orientation And Monolayer Effects In Hybrid Perovskite Solar Cells, Jacob M. Artz

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Methylammonium lead triiodide (MAPbI3) has garnered attention due to their high solar cell efficiencies and low cost to manufacture, but commercialization is not yet possible owing to poor environmental stability. Thus, researchers seek ways which optimize the performance of the MAPbI3 solar cell by modifying the architecture and through interfacial engineering of the charge transport layers. Difficulties in understanding these devices arise from ion migration, charge separation and recombination, and metastable, thermally active precessions of the methylammonium (MA) moiety in the lead iodide framework. In this work, focus is given to the perovskite and an adsorbed monolayer, 2,3,4,5,6-pentafluorothiophenol (C6F5SH), which …