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Articles 3361 - 3390 of 16785

Full-Text Articles in Materials Science and Engineering

Evaluation Of Anti‐Cracking Performance Of Recycled Concrete With Recycled Rubber/Sbs Composite Modified Asphalt, Li Xiaobin Mar 2023

Evaluation Of Anti‐Cracking Performance Of Recycled Concrete With Recycled Rubber/Sbs Composite Modified Asphalt, Li Xiaobin

Journal of China & Foreign Highway

In order to improve the crack resistance of recycled asphalt mixture, a new styrenic block copolymer (SBS)/rubber composite modified asphalt with excellent crack resistance was proposed for the regeneration of reclaimed asphalt pavement (RAP). Based on the creep of low temperature bending beam, confined temperature stress, and four-point bending fatigue test, the low temperature cracking resistance and fatigue cracking performance of composite modified asphalt and SBS-modified asphalt were studied. The results show that the addition of rubber can improve the low temperature and medium temperature crack resistance of recycled asphalt concrete, which may be related to the propagation of micro-cracks …

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Study On Anti‐Scattering Performance Of Asphalt Concrete On Aggregate Scattering Pavement Of Highway, Yang Siyuan, Chen Guiliang Mar 2023

Study On Anti‐Scattering Performance Of Asphalt Concrete On Aggregate Scattering Pavement Of Highway, Yang Siyuan, Chen Guiliang

Journal of China & Foreign Highway

Due to the lack of quantitative evaluation methods for aggregate scattering degree of expressway asphalt pavement in China and abroad, according to the disease characteristics of surface layer spalling, this paper adopted the Cantabro standard dispersion test to sample the concrete of the section with aggregate scattering of Huangqunan Expressway (G3) in Zhejiang Province. The dispersion impact damage modes of the mixture with different severity were analyzed, and the anti-dispersion performance of concrete was evaluated by mass loss rate and water absorption rate. The results show that aggregate scattering will reduce the density of the concrete structure at the surface …

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Study On The Effect Of Quicklime On The Properties Of Cold Mix Asphalt, Liu Tao, Yi Ming, Song Tao Mar 2023

Study On The Effect Of Quicklime On The Properties Of Cold Mix Asphalt, Liu Tao, Yi Ming, Song Tao

Journal of China & Foreign Highway

The low initial strength of cold mixed asphalt mixture leads to the delay of traffic opening time, and the large void ratio leads to poor water stability and other problems, which seriously hinder the development of cold mixed environment-friendly construction mode. In this paper, based on the principle that the heat of quicklime in the presence of water promotes the rapid loss of water in the cold mixed mixture, the mixing test and cohesion test of the MS-3 slurry cold mixed asphalt mixture with quicklime were carried out to explore the influence of quicklime on the demulsification time and cohesion. …

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Research On Design Process Of Toll Interchange‐Expressway In The Area Of Funiu Mountain, Zhang Jie, Yang Qing, Chai Xiaolong Mar 2023

Research On Design Process Of Toll Interchange‐Expressway In The Area Of Funiu Mountain, Zhang Jie, Yang Qing, Chai Xiaolong

Journal of China & Foreign Highway

Currently, the expressways under construction in Henan Province are mainly concentrated in the Funiu Mountain area in the west, such as Yaoshan–Luanchuan–Xixia Expressway, Xixia–Xichuan Expressway, Yingchi–Luanchuan Expressway, and Luanchuan–Lushi Expressway. These projects are characterized by complex terrain conditions, difficult design, large-scale engineering, and a cluster of long tunnels and grand bridges. Under such complex conditions, how to arrange the interchange reasonably and ensure the optimal project plan becomes the key point of successful project design. This paper summarized the typical characteristics of toll interchange in Funiu Mountain area in recent years and put forward the design process of design preparation, …

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Variable Speed Limit Control Method For Highway Under Dense Fog, Sun Jiancheng, Qiao Jiaxing Mar 2023

Variable Speed Limit Control Method For Highway Under Dense Fog, Sun Jiancheng, Qiao Jiaxing

Journal of China & Foreign Highway

In order to solve the problem of traffic safety on expressways under dense fog and change the original fixed speed limit measures, a variable speed limit control method based on the safe allowable speed was proposed. The speed limit value was calculated based on the regulations in road traffic safety law on the speed under dense fog by considering that the traffic law does not mention the road alignment conditions, road conditions, and other factors, and the monitor data was used to approximate replace the data of individual vehicles for data optimization, and the safe speed and safe distance of …

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Study On Dynamic Allocation Optimization Of Highway Pavement Maintenance Funds, Zou Yi Mar 2023

Study On Dynamic Allocation Optimization Of Highway Pavement Maintenance Funds, Zou Yi

Journal of China & Foreign Highway

The conflict between the lack of maintenance funds and the growth of maintenance demand restricts the improvement of highway pavement technologies. In this paper, the state space of pavement maintenance demand was defined by the technical condition of the pavement, and the state of demand under different maintenance measures was designed as a Markov decision process. The dynamic allocation optimization model of highway pavement maintenance funds was established, and the corresponding genetic algorithm was designed. Finally, an example was given to simulate the optimized model. The results show that the Markov decision process can dynamically allocate highway pavement maintenance funds, …

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Influence Factors Of Deicing And Thaw Performance Of Asphalt Mixture With Low Freezing Point, Zhou Shuiwen, Lin Fang, Zhang Xiaohua, Zhang Lingbo, Jiang Haoqiu Mar 2023

Influence Factors Of Deicing And Thaw Performance Of Asphalt Mixture With Low Freezing Point, Zhou Shuiwen, Lin Fang, Zhang Xiaohua, Zhang Lingbo, Jiang Haoqiu

Journal of China & Foreign Highway

The conductivity test was used to study the release law of thawing and deicing components. The freezing test was used to study the cooling law of the mixture, and the thawing rate test was used to study the thawing and deicing performance. The results show that the release of thawing and deicing components of materials with a low freezing point is temperature-dependent, and the release at the high temperature is 3.49–3.77 times that at the low temperature. The granular materials tend to dissolve in water, which results in the release rate of thawing and deicing components faster than that of …

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Experimental Analysis On Recycling And Mechanical Properties Of Waste Cement, Chen Liang Mar 2023

Experimental Analysis On Recycling And Mechanical Properties Of Waste Cement, Chen Liang

Journal of China & Foreign Highway

In order to recycle waste cement, construction waste cement materials were collected in the laboratory, and they were crushed, ground, and heat treated to facilitate reuse. Then, the waste cement was combined with the commonly used active fly ash admixture to prepare a new cement material for test analysis. The results show that the new cement material produced by industrial by-product, fly ash and waste cement material is feasible. A small amount of construction waste cement material (about 5%) can increase the 28-day compressive strength of cement by more than 50%, and the compressive strength of the prepared building material …

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Experimental Study On Characteristics And Stability Of Different Aged Steel Slag Aggregate, Zhang Hongri, Wang Guiyao, Feng Jian, Lan Tianzhu, Wu Tao Mar 2023

Experimental Study On Characteristics And Stability Of Different Aged Steel Slag Aggregate, Zhang Hongri, Wang Guiyao, Feng Jian, Lan Tianzhu, Wu Tao

Journal of China & Foreign Highway

Steel slag aggregate has good building material properties, but the utilization rate of steel slag in road engineering is low at present. In this paper, the chemical composition, basic physical and mechanical indexes, f⁃CaO, f⁃MgO, pulverization rate, CRB expansion rate, and other indexes of open-air aged steel slag aggregate in Fangchenggang, Guangxi Province for 0, 6, and 12 months were studied. The results show that the physical and mechanical properties of steel slag aggregate basically meet the requirements of road base materials and subgrade fillers, but the indexes of f⁃CaO, pulverization rate, and CRB expansion rate of steel slag aggregate …

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Study On Effect Of Fiber Stabilizers On Water Temperature Cycle Damage Resistance Of Drainage Asphalt Mixtures, Liu Fuming, Wu Di, He Qingde, Yang Zhiping Mar 2023

Study On Effect Of Fiber Stabilizers On Water Temperature Cycle Damage Resistance Of Drainage Asphalt Mixtures, Liu Fuming, Wu Di, He Qingde, Yang Zhiping

Journal of China & Foreign Highway

In order to study the effect of fiber stabilizer on the water temperature cycle damage resistance of drainage asphalt mixture, drainage asphalt mixture without fiber stabilizer and with wood fiber, polyester fiber, and basalt fiber, respectively, were compared through tests. By standard dispersion test and immersed dispersion test, the anti-spalling ability of the mixture was analyzed. Under the same asphalt condition, the standard dispersion loss of the drainage asphalt mixture was reduced to different degrees after adding fiber stabilizer, which could increase the anti-spalling property of the drainage asphalt mixture to some extent. The splitting, indirect tensile, and rutting tests …

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Restoration And Modification Of A Sputter Tool For The Deposition Of A Zno Guiding Layer Via Rf Sputtering, Matthew Watson Mar 2023

Restoration And Modification Of A Sputter Tool For The Deposition Of A Zno Guiding Layer Via Rf Sputtering, Matthew Watson

USF Tampa Graduate Theses and Dissertations

In this thesis, a novel sputter tool was restored and modified to deposit a ZnO film for future applications as a guiding layer on a surface acoustic wave (SAW) device. Some restorations and modifications included a water chiller being sized and added to the tool, leak checks to establish an ultra-high vacuum of 10-6 Torr, then finally heat lamps for temperature control were installed. Once modified, one of the preexisting magnetrons was utilized to deposit a ZnO via RF sputtering onto a quartz substrate. The layer was characterized via energy-dispersive X-ray spectroscopy which showed the existence of Zn on the …

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Oh, My Darling Clementine: A Detailed History And Data Repository Of The Los Alamos Plutonium Fast Reactor, Hannah K. Patenaude, Franz J. Freibert Mar 2023

Oh, My Darling Clementine: A Detailed History And Data Repository Of The Los Alamos Plutonium Fast Reactor, Hannah K. Patenaude, Franz J. Freibert

College of Sciences Graduate Student Research

The Los Alamos Plutonium Fast Reactor, Clementine, provided the first fast neutron spectrum using a metallic plutonium fuel system and liquid mercury coolant. Clementine is often mentioned in the history of fast, metal-fueled, or metal-cooled designs, with little public information regarding the specifications or timeline. This paper contains a synopsis of each report regarding the development, operation, experimental results, failures, and subsequent disassembly of Clementine to explore this unique reactor within the context of modern advanced reactor development.

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The Influence Of Bipolar Electrochemical Cell Geometry On The Studies Of Pitting Corrosion, Amin Kazem Ghamsari Mar 2023

The Influence Of Bipolar Electrochemical Cell Geometry On The Studies Of Pitting Corrosion, Amin Kazem Ghamsari

USF Tampa Graduate Theses and Dissertations

Bipolar electrochemistry (BPE) is a technique that provides a wireless alternative totraditional electrochemistry to elicit redox reactions. It has been utilized in different applications, including studying localized corrosion, gradient electrodeposition, propulsion of micromotors, and water treatment. The popularity of the method is not solely dependent on its wirelessness but more due to the simultaneous presence of cathodic and anodic poles on the same surface, which also begets its name as bipolar. The concept of the method is based on the polarization of conductive objects in an electric field in the presence of an electrolyte. In BPE, instead of controlling the …

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Lead-Free Perovskite Homojunction-Based Htm-Free Perovskite Solar Cells: Theoretical And Experimental Viewpoints, Sajid Sajid, Salem Alzahmi, Imen Ben Salem, Jongee Park, Ihab M. Obaidat Mar 2023

Lead-Free Perovskite Homojunction-Based Htm-Free Perovskite Solar Cells: Theoretical And Experimental Viewpoints, Sajid Sajid, Salem Alzahmi, Imen Ben Salem, Jongee Park, Ihab M. Obaidat

All Works

Simplifying the design of lead-free perovskite solar cells (PSCs) has drawn a lot of interest due to their low manufacturing cost and relative non-toxic nature. Focus has been placed mostly on reducing the toxic lead element and eliminating the requirement for expensive hole transport materials (HTMs). However, in terms of power conversion efficiency (PCE), the PSCs using all charge transport materials surpass the environmentally beneficial HTM-free PSCs. The low PCEs of the lead-free HTM-free PSCs could be linked to poorer hole transport and extraction as well as lower light harvesting. In this context, a lead-free perovskite homojunction-based HTM-free PSC was …

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Fast-, Light-Cured Scintillating Plastic For 3d-Printing Applications, Brian G. Frandsen, Michael Febbraro, Thomas Ruland, Theodore W. Stephens, Paul A. Hausladen, Juan J. Manfredi, James E. Bevins Mar 2023

Fast-, Light-Cured Scintillating Plastic For 3d-Printing Applications, Brian G. Frandsen, Michael Febbraro, Thomas Ruland, Theodore W. Stephens, Paul A. Hausladen, Juan J. Manfredi, James E. Bevins

Faculty Publications

Additive manufacturing techniques enable a wide range of possibilities for novel radiation detectors spanning simple to highly complex geometries, multi-material composites, and metamaterials that are either impossible or cost prohibitive to produce using conventional methods. The present work identifies a set of promising formulations of photocurable scintillator resins capable of neutron-gamma pulse shape discrimination (PSD) to support the additive manufacturing of fast neutron detectors. The development of these resins utilizes a step-by-step, trial-and-error approach to identify different monomer and cross-linker combinations that meet the requirements for 3D printing followed by a 2-level factorial parameter study to optimize the radiation detection …

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Self-Healing Properties Of Augmented Injectable Hydrogels Over Time, Connor Castro, Zachary R. Brown, Erik Brewer Mar 2023

Self-Healing Properties Of Augmented Injectable Hydrogels Over Time, Connor Castro, Zachary R. Brown, Erik Brewer

Henry M. Rowan College of Engineering Departmental Research

Injectable polymers offer great benefits compared to other types of implants; however, they tend to suffer from increased mechanical wear and may need a replacement implant to restore these mechanical properties. The purpose of this experiment is to investigate an injectable hydrogel's self-healing ability to augment itself to a previously molded implant. This was accomplished by performing a tensile strength test to examine potential diminishing mechanical properties with increasing time, as well as dye penetration tests to examine the formation of interfacial bonds between healed areas of hydrogels. There were several time points in between injections that were explored, from …

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Tunable, Reconfigurable, And Programmable Acoustic Metasurfaces: A Review, Ali Zabihi, Chadi Ellouzi, Chen Shen Mar 2023

Tunable, Reconfigurable, And Programmable Acoustic Metasurfaces: A Review, Ali Zabihi, Chadi Ellouzi, Chen Shen

Henry M. Rowan College of Engineering Departmental Research

The advent of acoustic metasurfaces (AMs), which are the two-dimensional equivalents of metamaterials, has opened up new possibilities in wave manipulation using acoustically thin structures. Through the interaction between the acoustic waves and the subwavelength scattering, AMs exhibit versatile capabilities to control acoustic wave propagation such as by steering, focusing, and absorption. In recent years, this vibrant field has expanded to include tunable, reconfigurable, and programmable control to further expand the capacity of AMs. This paper reviews recent developments in AMs and summarizes the fundamental approaches for achieving tunable control, namely, by mechanical tuning, active control, and the use of …

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Turning Dead Leaves Into An Active Multifunctional Material As Evaporator, Photocatalyst, And Bioplastic, Siyuan Fang, Xingyi Lyu, Tian Tong, Aniqa Ibnat Lim, Tao Li, Jiming Bao, Yun Hang Hu Mar 2023

Turning Dead Leaves Into An Active Multifunctional Material As Evaporator, Photocatalyst, And Bioplastic, Siyuan Fang, Xingyi Lyu, Tian Tong, Aniqa Ibnat Lim, Tao Li, Jiming Bao, Yun Hang Hu

Michigan Tech Publications, Part 1

Large numbers of leaves fall on the earth each autumn. The current treatments of dead leaves mainly involve completely destroying the biocomponents, which causes considerable energy consumption and environmental issues. It remains a challenge to convert waste leaves into useful materials without breaking down their biocomponents. Here, we turn red maple dead leaves into an active three-component multifunctional material by exploiting the role of whewellite biomineral for binding lignin and cellulose. Owing to its intense optical absorption spanning the full solar spectrum and the heterogeneous architecture for effective charge separation, films of this material show high performance in solar water …

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Closed-Loop Recyclable Plastics From Poly(Ethyl Cyanoacrylate), Allison J. Christy, Scott T. Phillips Mar 2023

Closed-Loop Recyclable Plastics From Poly(Ethyl Cyanoacrylate), Allison J. Christy, Scott T. Phillips

Materials Science and Engineering Faculty Publications and Presentations

Ethyl cyanoacrylate is a highly reactive monomer that has been used nearly exclusively to make Super Glue and related fast-setting adhesives. Here, we describe transformation of this highly abundant, readily available monomer into a closed-loop recyclable plastic that could supplant currently used (and often unrecycled/unrecyclable) plastics, such as poly(styrene). We report polymerization conditions, plastic-processing methods, and plastic-recycling protocols for poly(ethyl cyanoacrylate) plastics that make the Super Glue monomer a viable starting material for a next generation of closed-loop recyclable plastics. The processes described are scalable, and the plastics can be recycled in a closed-loop process with >90% yields, even when …

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Effect Of Substituent Location On The Relationship Between The Transition Dipole Moments, Difference Static Dipole, And Hydrophobicity In Squaraine Dyes For Quantum Information Devices, Maia Ketteridge, Austin Biaggne, Ryan Rau, German Barcenas, Olga A. Mass, William B. Knowlton, Bernard Yurke, Lan Li Mar 2023

Effect Of Substituent Location On The Relationship Between The Transition Dipole Moments, Difference Static Dipole, And Hydrophobicity In Squaraine Dyes For Quantum Information Devices, Maia Ketteridge, Austin Biaggne, Ryan Rau, German Barcenas, Olga A. Mass, William B. Knowlton, Bernard Yurke, Lan Li

Materials Science and Engineering Faculty Publications and Presentations

Aggregates of organic dyes that exhibit excitonic coupling have a wide array of applications, including medical imaging, organic photovoltaics, and quantum information devices. The optical properties of a dye monomer, as a basis of dye aggregate, can be modified to strengthen excitonic coupling. Squaraine (SQ) dyes are attractive for those applications due to their strong absorbance peak in the visible range. While the effects of substituent types on the optical properties of SQ dyes have been previously examined, the effects of various substituent locations have not yet been investigated. In this study, density functional theory (DFT) and time-dependent density functional …

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Magnetic Nanocomposites For The Remote Activation Of Sulfate Radicals For The Removal Of Rhodamine B, Pranto Paul, Marissa Nicholson, J. Zach Hilt Mar 2023

Magnetic Nanocomposites For The Remote Activation Of Sulfate Radicals For The Removal Of Rhodamine B, Pranto Paul, Marissa Nicholson, J. Zach Hilt

UK CARES Faculty Publications

The widespread presence of numerous organic contaminants in water poses a threat to the ecological environment and human health. Magnetic nanocomposites exposed to an alternating magnetic field (AMF) have a unique ability for magnetically mediated energy delivery (MagMED) resulting from the embedded magnetic nanoparticles; this localized energy delivery and associated chemical and thermal effects are a potential method for removing contaminants from water. This work developed a novel magnetic nanocomposite—a polyacrylamide-based hydrogel loaded with iron oxide nanoparticles. For this magnetic nanocomposite, persulfate activation and the contamination removal in water were investigated. Magnetic nanocomposites were exposed to AMF with a model …

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Austenite Formation And Manganese Partitioning During Double Soaking Of An Ultralow Carbon Medium-Manganese Steel, Josh J. Mueller, Alexandra G. Glover, David K. Matlock, John G. Speer, Emmanuel De Moor Mar 2023

Austenite Formation And Manganese Partitioning During Double Soaking Of An Ultralow Carbon Medium-Manganese Steel, Josh J. Mueller, Alexandra G. Glover, David K. Matlock, John G. Speer, Emmanuel De Moor

Michigan Tech Publications, Part 1

Double soaking (DS) is a thermal processing route intended to produce austenite–martensite microstructures in steels containing austenite-stabilizing additions and consists of intercritical annealing (primary soaking), followed by heating and brief isothermal holding at an increased temperature (secondary soaking), and quenching. Herein, experimental dilatometry during DS of a medium-manganese (Mn) steel with nominally 7 wt% Mn and an ultralow residual carbon concentration, in combination with phase-field simulations of austenite formation during secondary soaking, is presented. The feasibility of maintaining heterogeneous Mn distributions during DS is demonstrated and insight is provided on the effects of the secondary soaking temperature and prior Mn …

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Precious Plastics - Plastic Brick Machine Fabrication, Timothy Ukaobasi Kanu, Evi Paraskevi Troulis Mar 2023

Precious Plastics - Plastic Brick Machine Fabrication, Timothy Ukaobasi Kanu, Evi Paraskevi Troulis

Architectural Engineering

The goal of this research is to determine the structural parameters of the recycled plastic polypropylene when molded into bricks resembling CMU blocks. To accomplish this, three mechanisms had to be assembled: the shredder, the injector, and the 1x1 mold. A tensile and compression test were to be performed on the plastic brick, and the values would be used to compare the tensile and compressive strength of PP plastic bricks, as well as their modulus of elasticity and stress vs. Strain performance. These values would be analyzed to determine whether it would be feasible to build an entire plastic wall. …

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Particle Migration In Large Cross-Section Ceramic On-Demand Extrusion Components, Austin J. Martin, Wenbin Li, Jeremy Lee Watts, Gregory E. Hilmas, Ming-Chuan Leu, Tieshu Huang Mar 2023

Particle Migration In Large Cross-Section Ceramic On-Demand Extrusion Components, Austin J. Martin, Wenbin Li, Jeremy Lee Watts, Gregory E. Hilmas, Ming-Chuan Leu, Tieshu Huang

Materials Science and Engineering Faculty Research & Creative Works

Ceramic On-Demand Extrusion (CODE) is a direct ink writing process which allows for the creation of near theoretically dense ceramic components with large cross-sections due to oil-assisted drying. Yttria-stabilized zirconia (YSZ) colloidal pastes (∼d50 ≲ 1 µm) were used in CODE to produce dense (multi-road infill and ≳ 98% relative density), large continuous volume (> 1 cm3), and high fidelity (nozzle diameters ≲ 1 mm) structural ceramic components. However, many of these printed components underwent significant particle migration after forming. The reason for this particle migration defect was investigated using the coffee-ring effect for dilute solutions and rheological methods for …

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Description Of Reaction And Vibrational Energetics Of Co2-Nh3interaction Using Quantum Computing Algorithms, Manh Tien Nguyen, Yueh-Lin Lee, Dominic Alfonso, Qing Shao, Yuhua Duan Mar 2023

Description Of Reaction And Vibrational Energetics Of Co2-Nh3interaction Using Quantum Computing Algorithms, Manh Tien Nguyen, Yueh-Lin Lee, Dominic Alfonso, Qing Shao, Yuhua Duan

Markey Cancer Center Faculty Publications

CO2 capture is critical to solving global warming. Amine-based solvents are extensively used to chemically absorb CO2. Thus, it is crucial to study the chemical absorption of CO2 by amine-based solvents to better understand and optimize CO2 capture processes. Here, we use quantum computing algorithms to quantify molecular vibrational energies and reaction pathways between CO2 and a simplified amine-based solvent model—NH3. Molecular vibrational properties are important to understanding kinetics of reactions. However, the molecule size correlates with the strength of anharmonicity effect on vibrational properties, which can be challenging to address using classical computing. Quantum computing can help enhance molecular …

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Characterizing Gesn Alloys By Sem/Eds And Photoluminescence Spectroscopy, Christopher M. Sutphin Mar 2023

Characterizing Gesn Alloys By Sem/Eds And Photoluminescence Spectroscopy, Christopher M. Sutphin

Theses and Dissertations

Germanium tin (GeSn) alloys are being studied as potential transition metal (Group IV) photoelectric semiconductors or optical detectors. GeSn alloys could be employed as an optically active material within a computer. Compared to current technologies, a direct band gap GeSn alloy can be engineered to operate with higher thermal stability and efficiency. The GeSn alloy studied was composed of Ge and Si substrates with various Sn percentages grown using remote plasma-enhanced chemical vapor deposition (RPECVD). Photoluminescence spectroscopy (PL) techniques were initially used to determine the GeSn properties, including the band gap. The Ge91.2Sn8.8 PL spectra suggested the …

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Influence Of Dilute Silicon Carbide Nanoparticle Additions To The Microstructure And Mechanical Properties Of Laser Powder Bed Fusion Molybdenum, Nathan E. Ellsworth Mar 2023

Influence Of Dilute Silicon Carbide Nanoparticle Additions To The Microstructure And Mechanical Properties Of Laser Powder Bed Fusion Molybdenum, Nathan E. Ellsworth

Theses and Dissertations

Consolidation of pure molybdenum through laser powder bed fusion and other additive manufacturing techniques is complicated by a high melting temperature, thermal conductivity, and ductile-to-brittle transition temperatures. Nano-sized silicon carbide particles (0.1 wt%) were homogeneously mixed with molybdenum powder and the printing characteristics, chemical composition, microstructure, and mechanical properties were compared to pure molybdenum for scan speeds of 100, 200, 400, and 800 mm/s. The addition of silicon carbide improved the consolidation and mechanical properties and the oxygen content was reduced. Two mechanisms of oxygen reduction were identified as responsible for the improvements: oxidation of free carbon and the creation …

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Angle Resolved Photoelectron Spectroscopy Study Of Germanium Tin: Experimentally Determined Electronic Band Gap And Surface Analysis, Jeremy M. Hunter Mar 2023

Angle Resolved Photoelectron Spectroscopy Study Of Germanium Tin: Experimentally Determined Electronic Band Gap And Surface Analysis, Jeremy M. Hunter

Theses and Dissertations

The germanium tin band gap is responsive to wavelengths in the mid to near infrared spectrum; this shows promise in meeting the detection demands of the next generation infrared detectors. Recent developments in germanium tin (GeSn) alloy growth techniques have peaked the scientific community’s interest in GeSn based optoelectrical and detection devices. Detection materials made entirely of group IV elements are compatible with complementary metal-oxide semiconductor manufacturing techniques. Understanding the surface chemistry of this alloy is fundamental for solid state device design and must be analyzed to optimize device performance. Studies have shown that with the addition of tin, the …

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Material Property Dependence Of Nanoparticle Silicon Carbide Alloying In Additively Manufactured Molybdenum, Andrew P. Mason Mar 2023

Material Property Dependence Of Nanoparticle Silicon Carbide Alloying In Additively Manufactured Molybdenum, Andrew P. Mason

Theses and Dissertations

The structural performance of additively manufactured Mo printed by LPBF can be significantly improved by nanoparticle alloying. Previous AFIT studies of SiC nanoparticle addition conducted by Ellsworth (2022) et al. demonstrated increased powder consolidation, leading to reduced porosity, increased microhardness, and a shift in atomic defect concentrations. The addition of defected SiC particles is proposed to reduce in situ oxidation by acting as a sacrificial oxidizing agent and contributing to the formation of Mo disilicide secondary phases. This study investigated the relationship between laser powder bed fusion Mo microscale and nanoscale properties with varying SiC particle size while maintaining a …

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Novel Effects Of Grain Size And Ion Implantation On Grain Boundary Segregation In Ion Irradiated Austenitic Steel, Andrew K. Hoffman, Yongfeng Zhang, Maalavan Arivu, Li He, Kumar Sridharan, Yaqiao Wu, Rinat K. Islamgaliev, Ruslan Z. Valiev, Haiming Wen Mar 2023

Novel Effects Of Grain Size And Ion Implantation On Grain Boundary Segregation In Ion Irradiated Austenitic Steel, Andrew K. Hoffman, Yongfeng Zhang, Maalavan Arivu, Li He, Kumar Sridharan, Yaqiao Wu, Rinat K. Islamgaliev, Ruslan Z. Valiev, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

Nuclear Reactor Environments Are Extreme in Nature Due to the Combination of Exposure to Corrosive Coolant, Mechanical Stresses, and Neutron Irradiation Damage. This Combination of Environments Can Lead to Irradiation Induced/assisted Precipitation, Segregation, and Embrittlement Coupled with Enhanced Creep and Stress Corrosion Cracking. While Nanostructured Materials Are of Interest in a Variety of Applications Due to their Unique Properties Including High Mechanical Strength, for Nuclear Applications Nanostructured Materials Have the Added Benefit of Irradiation Resistance Due to the High-Volume Density of Sinks for Irradiation-Induced Defects. in This Study, We Show Unique Radiation-Induced Segregation (RIS) Behavior in Nanocrystalline 304 Stainless Steel …

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