4,6-O-Phenylethylidene Acetal Protected D-Glucosamine Carbamate-Based Gelators And Their Applications For Multi-Component Gels,
2022
Old Dominion University
4,6-O-Phenylethylidene Acetal Protected D-Glucosamine Carbamate-Based Gelators And Their Applications For Multi-Component Gels, Pooja Sharma, Guijun Wang
Chemistry & Biochemistry Faculty Publications
The self-assembly of carbohydrate-based low molecular weight gelators has led to useful advanced soft materials. The interactions of the gelators with various cations and anions are important in creating novel molecular architectures and expanding the scope of the small molecular gelators. In this study, a series of thirteen new C-2 carbamates of the 4,6-O-phenylethylidene acetalprotected D-glucosamine derivatives has been synthesized and characterized. These compounds are rationally designed from a common sugar template. All carbamates synthesized were found to be efficient gelators and three compounds are also hydrogelators. The resulting gels were characterized using optical microscopy, atomic force microscopy, …
Investigation Of Mechanical Properties Of Parts Fabricated With Gas- And Water-Atomized 304l Stainless Steel Powder In The Laser Powder Bed Fusion Process,
2022
Missouri University of Science and Technology
Investigation Of Mechanical Properties Of Parts Fabricated With Gas- And Water-Atomized 304l Stainless Steel Powder In The Laser Powder Bed Fusion Process, M. Hossein Sehhat, Austin T. Sutton, Chia Hung Hung, Joseph William Newkirk, Ming-Chuan Leu
Materials Science and Engineering Faculty Research & Creative Works
The use of gas-atomized powder as the feedstock material for the laser powder bed fusion (LPBF) process is common in the additive manufacturing (AM) community. Although gas-atomization produces powder with high sphericity, its relatively expensive production cost is a downside for application in AM processes. Water atomization of powder may overcome this limitation due to its low-cost relative to the gas-atomization process. In this work, gas- and water-atomized 304L stainless steel powders were morphologically characterized through scanning electron microscopy (SEM). The water-atomized powder had a wider particle size distribution and exhibited less sphericity. Measuring powder flowability using the Revolution Powder …
Manufacturing Of A Ceramic Turbine Rotor For A Compact Jet Engine,
2022
Air Force Institute of Technology
Manufacturing Of A Ceramic Turbine Rotor For A Compact Jet Engine, Bryan T. Leicht
Theses and Dissertations
The primary goal of this study was to develop a low-cost, timely, scalable manufacturing method that produced a ceramic turbine that can be tested as a drop-in replacement on a JetCat P400 small scale gas turbine engine. This research compared two processes for manufacturing a ceramic turbine utilizing a pour casting method and 3D printing using stereolithography ceramic manufacturing (SLCM). The pour casting method used Silicon Nitride to create a cast turbine using a sacrificial 3D printed mold. The SLCM method evaluated producing an alumina turbine using an ADMATEC Admaflex 300 SLCM printer to directly print a ceramic turbine. This …
Thermal Considerations For Film Cooling Materials With Anisotropic Thermal Conductivity,
2022
Air Force Institute of Technology
Thermal Considerations For Film Cooling Materials With Anisotropic Thermal Conductivity, Carol E. Bryant
Theses and Dissertations
Higher performance requirements and reduced core sizes are driving increases in turbine inlet temperature in gas turbine engines, surpassing the melting point of advanced materials. Newer materials, such as composites, are being introduced into the hot sections of gas turbine engines. Components in the hot section use film cooling to prevent melting. One unique aspect of some high-temperature composites is they have a bulk anisotropic thermal conductivity, therefore heat flow differs relative to traditional metallic components. Film cooling designs can be revolutionized by leveraging anisotropy in high-temperature materials. The purpose of this research is to examine thermal considerations for using …
Formulation And Characterization Of Fast-Curing Plastic Scintillators With High-Z Loading,
2022
Air Force Institute of Technology
Formulation And Characterization Of Fast-Curing Plastic Scintillators With High-Z Loading, Theodore W. Stephens
Theses and Dissertations
Development of novel fast-curing plastic scintillators is highly advantageous due to their potential to be manufactured via 3D printing. Several formulations were developed that exhibit enhanced photon sensitivity, producing modest but discernible photopeaks at an incident gamma energy of 122 keV. The photon sensitivity is achieved via bismuth high-Z loading; however, this practice typically results in diminished light yields. Subsequent formulations, which varied the photoinitiator concentration and curing time, demonstrated successful curing with sufficient plastic hardness, reduced purple discoloration, reduced heat buildup during curing, and resulted in less cracking during the curing process, all of which were correlated with lower …
Analysis Of Microscopic Carbon Fiber Fragments,
2022
Air Force Institute of Technology
Analysis Of Microscopic Carbon Fiber Fragments, Zachary R. Scott
Theses and Dissertations
Carbon Fiber (CF) has different tensile strengths and transverse moduli depending on how they are fabricated. Some CF is export controlled as it can be used for weapons, spacecraft, or gas centrifuges for enriching nuclear fuel. This research project explored a new way to prepare micron sized single CF threads to measure their transverse modulus and compare the moduli of non-export controlled CF to that of an export controlled CF. Five total polyacrylonitrile (PAN) fibers were used in this project, one of which was an export controlled fiber.
Determination Of Nonlinear Optical Properties For Gallium Arsenide Phosphide Ternary Compounds And For Tin Thiohypodiphosphate,
2022
Air Force Institute of Technology
Determination Of Nonlinear Optical Properties For Gallium Arsenide Phosphide Ternary Compounds And For Tin Thiohypodiphosphate, Peter F. Norris
Theses and Dissertations
The Department of Defense and the commercial sector rely on coherent light sources to emit light that transmits through the atmosphere. Nonlinear optical effects in crystalline materials can be used to generate the laser waves, but certain nonlinear effects negatively impact the performance of laser generating materials. This thesis focuses on characterizing nonlinear optical properties for gallium arsenide phosphide ternary compounds and for tin thiohypodiphosphate. The Maker Fringe experiment is used to determine the d-coefficients of the materials, which describe the magnitude of the nonlinear response of the material. The Z-Scan experiment is used to calculate the nonlinear refractive …
Towards The Integration Of Ferroelectric Negative Capacitance With Gallium Oxide Semiconductors For High Power Applications,
2022
Air Force Institute of Technology
Towards The Integration Of Ferroelectric Negative Capacitance With Gallium Oxide Semiconductors For High Power Applications, Guillermo A. Salcedo
Theses and Dissertations
Gallium oxide is a relatively new semiconductor material with characteristics auspicious for high frequency and high-voltage applications. Although several research groups have already demonstrated radio-frequency (RF) devices on Ga2O3 with remarkable features, there is still room for improvement. For instance, the operating frequency of RF field-effect transistors (FET) decreases with the parasitic capacitance, which can be counteracted by higher gate capacitance. Implementing ferroelectric dielectrics with suitable parameters in Ga2O3 FET promises to enhance the gate capacitance and therefore increase operating frequency. This work investigated the effect of various factors (film composition, film thickness, TiN …
Potential Solution To Meet Growing Demands Of Refractory Metal: Selective Laser Melting Of Molybdenum-Tungsten Alloy,
2022
Air Force Institute of Technology
Potential Solution To Meet Growing Demands Of Refractory Metal: Selective Laser Melting Of Molybdenum-Tungsten Alloy, Jae Yu
Theses and Dissertations
Selective laser melting (SLM) of refractory metals has been of high interest in research due to the metals’ potential desirable characteristics in aeronautical and space applications. In particular, molybdenum and tungsten have been the focus of several studies in the search for high temperature and high strength purposes in applications like supersonic aircraft, re-entry vehicles, nuclear fission, power generation, and other space systems. However, there is still a significant knowledge gap to process defect-free alloys and making use of them in practical engineering functions. The aim of this study is to characterize the relationship between the microstructure and mechanical properties …
Recent Advances In Structural Regulation On Non-Precious Metal Catalysts For Oxygen Reduction Reaction In Alkaline Electrolytes,
2022
1. State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry,Chinese Academy of Sciences, Changchun 130022, Jilin, China;2. University of Science and Technology of China, Hefei 230026, Anhui, China;
Recent Advances In Structural Regulation On Non-Precious Metal Catalysts For Oxygen Reduction Reaction In Alkaline Electrolytes, Xue Wang, Li Zhang, Chang-Peng Liu, Jun-Jie Ge, Jian-Bing Zhu, Wei Xing
Journal of Electrochemistry
Oxygen reduction reaction (ORR) in alkaline electrolytes is an important electrochemical process for metal-air batteries and anion exchange membrane fuel cells (AEMFCs). However, the sluggish kinetics spurs intensive research on searching robust electrocatalysts. Non-precious metal catalysts (NPMCs) that can circumvent the cost and scarcity issues associated with platinum (Pt)-based materials have been pursued and the challenges lie in the performance improvement to rival Pt-based benchmarks. As the composition and structure of the NPMCs have a significant impact on the catalytic performance, precise regulation on the catalyst structure holds great promise to bridge the activity gap between NPMCs and Pt-based benchmarks. …
Magnetic Resonance In Metal-Ion Batteries: From Nmr (Nuclear Magnetic Resonance) To Epr (Electron Paramagnetic Resonance),
2022
Shanghai Key Laboratory of Magnetic Resonance, State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, P. R. China;
Magnetic Resonance In Metal-Ion Batteries: From Nmr (Nuclear Magnetic Resonance) To Epr (Electron Paramagnetic Resonance), Bing-Wen Hu, Chao Li, Fu-Shan Geng, Ming Shen
Journal of Electrochemistry
Metal-ion batteries have changed our quotidian lives. The research on the electrode materials for metal-ion battery is the key to improve the performance of the battery. Therefore, understanding the structure-performance relationship of the electrode materials can help to improve the energy density and power density of the materials. Magnetic resonance, including nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR), has been continuously improved during the past three decades, and has gradually become one of the important technologies to study the structure-performance relationship of electrode materials. This paper summarizes the progress of magnetic resonance research from our group on several …
Recent Advances In Electrochemical Kinetics Simulations And Their Applications In Pt-Based Fuel Cells,
2022
1. Collaborative Innovation Center of Chemistry for Energy Material, Key Laboratory of Computational Physical Science (Ministry of Education), Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200433, China;
Recent Advances In Electrochemical Kinetics Simulations And Their Applications In Pt-Based Fuel Cells, Ji-Li Li, Ye-Fei Li, Zhi-Pan Liu
Journal of Electrochemistry
Theoretical simulations of electrocatalysis are vital for understanding the mechanism of the electrochemical process at the atomic level. It can help to reveal the in-situ structures of electrode surfaces and establish the microscopic mechanism of electrocatalysis, thereby solving the problems such as electrode oxidation and corrosion. However, there are still many problems in the theoretical electrochemical simulations, including the solvation effects, the electric double layer, and the structural transformation of electrodes. Here we review recent advances of theoretical methods in electrochemical modeling, in particular, the double reference approach, the periodic continuum solvation model based on the modified Poisson-Boltzmann …
Facet Dependent Oxygen Evolution Activity Of Spinel Cobalt Oxides,
2022
1. Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China;2. Petrochemical Catalyst Lab., Lanzhou Petrochemical Research Center, Petrochemical Research Institute, PetroChina Company Limited, Lanzhou 730060, China;
Facet Dependent Oxygen Evolution Activity Of Spinel Cobalt Oxides, Li-Hua Zhang, Hong-Yuan Chuai, Hai Liu, Qun Fan, Si-Yu Kuang, Sheng Zhang, Xin-Bin Ma
Journal of Electrochemistry
Water splitting is a promising technology to produce clean hydrogen if powered by renewable energies, where oxygen evolution is the rate determining step at an anode. Here we adjust the different crystal planes of the cobalt oxides catalyst to expose more effective active sites through a hydrothermal process, so as to improve the reaction activity for oxygen evolution. The samples were well characterized by TEM, SEM and XRD. Among the three synthetic crystal planes (100), (111) and (110) of spinel cobalt oxides, the (100) crystal plane has the highest intrinsic activity. Combining in-situ infrared and DFT calculations, we …
Selective Co2 Reduction To Formate On Heterostructured Sn/Sno2 Nanoparticles Promoted By Carbon Layer Networks,
2022
Shanghai Key Lab of Chemical Assessment and Sustainability, School of Chemical Science and Engineering, Tongji University, Shanghai 200092;
Selective Co2 Reduction To Formate On Heterostructured Sn/Sno2 Nanoparticles Promoted By Carbon Layer Networks, Xue Teng, Yanli Niu, Shuaiqi Gong, Xuan Liu, Zuofeng Chen
Journal of Electrochemistry
Tin (Sn)-based materials have emerged as promising electrocatalysts for selective reduction of CO2 to formate, but their overall performances are still limited by electrode structures which govern the accessibility to active sites, the electron transfer kinetics, and the catalytic stability. In this study, the heterostructured Sn/SnO2 nanoparticles dispersed by N-doped carbon layer networks (Sn/SnO2@NC) were synthesized by a melt-recrystallization method taking the low melting point of Sn (m.p. 232oC). The N-doped carbon layer networks derived from polydopamine could attract more electrons on the electrocatalyst, serve as conductive agents and protect the ultrafine nanoparticles from …
Mass Loading Optimization For Ethylene Glycol Oxidation At Different Potential Regions,
2022
1. School of Materials Science and Engineering, Nanyang Technological University, 639798 Singapore;2. Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 138634 Singapore;3. Beijing Innovation Center for Engineering Science and Advanced Technology (BIC-ESAT), Beijing Key Laboratory for Magnetoelectric Materials and Devices (BKL-MMD), School of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China;
Mass Loading Optimization For Ethylene Glycol Oxidation At Different Potential Regions, Sheng-Nan Sun, Zhi-Chuan Xu
Journal of Electrochemistry
Designing and fabricating the electrocatalysts is attracting more and more attention in recent years due to a global interest in developing techniques for electrochemical energy conversion and storage, as well as elelectro-synthesis of valuable chemicals. The activity is one of the key performance parameters for electrocatalysts, while the observed activity can be affected by mass loading of electrocatalysts. Here, we take cobalt oxide (Co3O4)/graphite paper electrode (Co3O4/GPE) as a model electrode to demon-strate how the mass loading of Co3O4 catalyst influences ethylene glycol (EG) oxidation in alkaline (KOH) by …
Structural Degradation Of Ni-Rich Layered Oxide Cathode For Li-Ion Batteries,
2022
1. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;2. School of Information and Optoelectronic Science and Engineering & International Academy of Optoelectronics at Zhaoqing, South China Normal University, Guangzhou 510006, Guangdong, China;
Structural Degradation Of Ni-Rich Layered Oxide Cathode For Li-Ion Batteries, Jia-Yi Wang, Sheng-Nan Guo, Xin Wang, Lin Gu, Dong Su
Journal of Electrochemistry
Nickel(Ni)-rich layered oxide has been regarded as one of the most important cathode materials for the lithium-ion batteries because of its low cost and high energy density. However, the concerns in safety and durability of this compound are still challenging for its further development. On this account, the in-depth understanding in the structural factors determining its capacity attenuation is essential. In this review, we summarize the recent advances on the degradation mechanisms of Ni-rich layered oxide cathode. Progresses in the structure evolution of Ni-rich oxide are carefully combed in terms of inner evolution, surface evolution, and the property under thermal …
Influence Of Hydrophobicity On Excitonic Coupling In Dna-Templated Indolenine Squaraine Dye Aggregates,
2022
Boise State University
Influence Of Hydrophobicity On Excitonic Coupling In Dna-Templated Indolenine Squaraine Dye Aggregates, Olga A. Mass, Christopher K. Wilson, German Barcenas, Lan Li, Bernard Yurke, William B. Knowlton, Ryan D. Pensack, Jeunghoon Lee
Materials Science and Engineering Faculty Publications and Presentations
Control over the strength of excitonic coupling in molecular dye aggregates is a substantial factor for the development of technologies such as light harvesting, optoelectronics, and quantum computing. According to the molecular exciton model, the strength of excitonic coupling is inversely proportional to the distance between dyes. Covalent DNA templating was proved to be a versatile tool to control dye spacing on a subnanometer scale. To further expand our ability to control photophysical properties of excitons, here, we investigated the influence of dye hydrophobicity on the strength of excitonic coupling in squaraine aggregates covalently templated by DNA Holliday Junction (DNA …
Dissolution Amplification By Resonance And Cavitational Stimulation At Ultrasonic And Megasonic Frequencies,
2022
Missouri University of Science and Technology
Dissolution Amplification By Resonance And Cavitational Stimulation At Ultrasonic And Megasonic Frequencies, Ross A. Arnold, Shiqi Dong, Longwen Tang, Dale Prentice, Marie Collin, Juan Carlos Vega-Vila, Amaya Hernandez, Erika Callagon La Plante, Kirk Ellison, Aditya Kumar, Samanvaya Srivastava, Mathieu Bauchy, Dante Simonetti, Gaurav N. Sant
Materials Science and Engineering Faculty Research & Creative Works
Acoustic stimulation offers a green pathway for the extraction of valuable elements such as Si, Ca, and Mg via solubilization of minerals and industrial waste materials. Prior studies have focused on the use of ultrasonic frequencies (20-40 kHz) to stimulate dissolution, but mega sonic frequencies (≥1 MHz) offer benefits such as matching of the resonance frequencies of solute particles and an increased frequency of cavitation events. Here, based on dissolution tests of a series of minerals, it is found that dissolution under resonance conditions produced dissolution enhancements between 4x-to-6x in Si-rich materials (obsidian, albite, and quartz). Cavitational collapse induced by …
Effect Of Processing Parameters And Build Orientation On Microstructure And Performance Of Aisi Stainless Steel 304l Made With Selective Laser Melting Under Different Strain Rates,
2022
Missouri University of Science and Technology
Effect Of Processing Parameters And Build Orientation On Microstructure And Performance Of Aisi Stainless Steel 304l Made With Selective Laser Melting Under Different Strain Rates, Tan Pan, Xinchang Zhang, Aaron Flood, Sreekar Karnati, Wei Li, Joseph William Newkirk, Frank W. Liou
Materials Science and Engineering Faculty Research & Creative Works
Selective laser melting (SLM) process allows greater geometry flexibility; therefore, it has become more widespread in its deployment in the industry for fabricating metal alloys. However, a material characterization study is needed in order to understand better the correlation between the process, microstructure, and performance. In the current study, the raw SLM fabricated AISI stainless steel 304 L was fabricated with different processing parameters and build orientations (horizontal, inclined, and vertical). The tensile behavior was evaluated under different strain rates (0.0001/s, 0.001/s, 0.01/s, and 0.1/s) and then compared to commercial cold-rolled and annealed counterparts. Grain structures, tensile strength, elongation-to-failure, strain …
The Effect Of Sodium Polymethacrylate On The Rheology Of The Positive Paste And Performance Of The Lead-Acid Battery,
2022
Missouri University of Science and Technology
The Effect Of Sodium Polymethacrylate On The Rheology Of The Positive Paste And Performance Of The Lead-Acid Battery, Julian Kosacki, Dimitri Feys, Fatih Dogan
Materials Science and Engineering Faculty Research & Creative Works
No abstract provided.
