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Full-Text Articles in Engineering

Metal Coupon Testing In An Axial Rotating Detonation Engine For Wear Characterization, Gary S. North Jan 2020

Metal Coupon Testing In An Axial Rotating Detonation Engine For Wear Characterization, Gary S. North

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Rotating Detonation Engines (RDE) are being explored as a possible way to get better fuel efficiency for turbine engines than is otherwise possible. The walls of the RDE are subjected to cyclic thermal and mechanical shock loading at rates of approximately 3 KHz, with gas temperatures as high as 2976 K. This project performed testing with Inconel 625 and 304 stainless steel coupons in an RDE outer body to attempt to measure material ablation rates. Significant microstructural changes were observed to include grain growth in both alloys, carbide formation and grain boundary melting in Inconel, and formation of delta ferrite …


The Thermal And Mechanical Characteristics Of Lithiated Peo Lagp Composite Electrolytes, Jacob Michael Denney Jan 2020

The Thermal And Mechanical Characteristics Of Lithiated Peo Lagp Composite Electrolytes, Jacob Michael Denney

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Lithium-ion batteries are part of a multibillion-dollar industry that strives to meet the demands for an increasingly advanced technological future. Flexible batteries can be easily adapted from emerging novel wearable electronics to electrical vehicles and advanced solar panels. Solid-state batteries can greatly reduce the risk of fire or leaking hazardous materials due to puncture. For the development of solid-state flexible lithium based batteries polymer-ceramic composites are attractive electrolyte candidates because of their combined properties, such as electrical, thermal and mechanical properties, that not only overcome limitations from the base materials but may also render some enhanced performances resulting from the …


Stabilization Of Β-Cristobalite In The Sio2-Alpo4-Bpo4 System, Kathryn Doyle Jan 2020

Stabilization Of Β-Cristobalite In The Sio2-Alpo4-Bpo4 System, Kathryn Doyle

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Fused silica (silica glass) is transparent in the optical and near-infrared and has a low dielectric constant, making it suitable as a window material for radio frequency radiation. However, at high temperatures (>1100C), fused silica will easily creep and lose dimensional stability. Crystallized silica is much more creep resistant than fused silica. Silica crystallizes to many different structures including quartz, tridymite, and α- and β cristobalite. The only cubic polymorph, which is suitable for both optical and radio frequency transmission in polycrystalline form, is β -cristobalite. Unfortunately, this polymorph transforms to α-cristobalite at ~300C, and the volume change during …


Ab Initio Modeling Of An Electron Transport Layer Interface In Hybrid Perovskite Solar Cells, Krantikumar Subhash Pawar Jan 2020

Ab Initio Modeling Of An Electron Transport Layer Interface In Hybrid Perovskite Solar Cells, Krantikumar Subhash Pawar

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Hybrid organic-inorganic perovskite solar cell is an emerging technology which has shown the fastest advancement in power conversion efficiency within a few years since introduction, thus making it one of the clean energy breakthroughs. These cells are based on thin-film technology which makes them suitable to manufacture using low-cost solution processing methods. As these types of cells are easily tunable with the selection of different materials, interfacial engineering is an important approach to increasing their efficiency. One of the main hurdles in this regard is the loss caused by the recombination of separated charges. An approach to tackle these issues …