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Articles 1 - 30 of 414

Full-Text Articles in Engineering

Anomalous Of Resistance And Magnetic Susceptibility At 280-310 K And Ambient Pressure In Bismuth Cuprates Synthesized By Solar Energy, Dilbara Dj. Gulamova, Elyor B. Eshonkulov, Valeriya R. Li, Grigor I. Mamniashvili, Timur I. Gulamov May 2024

Anomalous Of Resistance And Magnetic Susceptibility At 280-310 K And Ambient Pressure In Bismuth Cuprates Synthesized By Solar Energy, Dilbara Dj. Gulamova, Elyor B. Eshonkulov, Valeriya R. Li, Grigor I. Mamniashvili, Timur I. Gulamov

CHEMISTRY AND CHEMICAL ENGINEERING

In order to obtain the full content of high-temperature superconducting phases using the “Super Fast Alloys Quenching” technology in the Large Solar Furnace (Parkent), precursors of bismuth cuprates of the series Bi1,7Pb0,3Sr2Ca(n-1)CunOy, n=3-30 were synthesized. Methods for study the properties of precursors are presented. The oriented nano-sized microstructure and layered structure of nanocrystalline nuclei are shown. The phase composition of the precursors at the beginning of the series (n=3-5) is represented by X-ray amorphous and crystalline phases. An increase in the content of CaO and CuO destabilizes the …

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Mechanical Properties And Microstructure Of Multi-Materials Fabricated Through A Combination Of Lpbf And Ded Additive Manufacturing Techniques, Christopher J. Bettencourt May 2024

Mechanical Properties And Microstructure Of Multi-Materials Fabricated Through A Combination Of Lpbf And Ded Additive Manufacturing Techniques, Christopher J. Bettencourt

All Graduate Theses and Dissertations, Fall 2023 to Present

This research explores the use of different metals combined through 3D-printing to enhance the performance of materials, with a focus on making heat exchangers more cost-effective for renewable energy. The goal is to replace a costly high-temperature alloy with a more affordable low-temperature alloy, using metal additive manufacturing for its benefits such as less material waste, faster production, reduced weight, and the ability to print entire assemblies in one go. The study delves into a unique combination of two 3D-printing techniques, Directed Energy Deposition and Laser Powder-Bed Fusion, to create a multi-material composed of stainless steel 316L and a nickel-based …

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The Characterization And Nanomechanical Properties Of Microstructurally Complex Systems, Kerry Ann Baker Jan 2024

The Characterization And Nanomechanical Properties Of Microstructurally Complex Systems, Kerry Ann Baker

Theses and Dissertations--Chemical and Materials Engineering

Since the dawn of civilization, the use of metals has played an integral role in the evolution of human society. Over the years, and with the introduction of new engineering and science, we have learned how to combine metals to create new metallic systems. We have expanded our understanding of dealloying and chemical reactions, and, in doing so, we created nanoporous metals. Our use of metals has evolved from basic alloys such as bronze and steel to more complex alloys such as multi-principal element alloys. Nanoporous gold is an advanced metallic system that can be created through the dealloying process. …

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The Effect Of Parameters In Cryogenic Treatment On Mechanical Properties Of Tool Steel: A Review, Ronaldus Caesariano Ekaputra, Myrna Ariati Mochtar Dec 2023

The Effect Of Parameters In Cryogenic Treatment On Mechanical Properties Of Tool Steel: A Review, Ronaldus Caesariano Ekaputra, Myrna Ariati Mochtar

Journal of Materials Exploration and Findings

Tool steel is classified as special alloy steel which proposed as dies or mold materials as their high mechanical properties and dimensional stability. In order to improve tool steel’s mechanical properties, heat treatment process, especially, cryogenic treatment is conducted. Cryogenic treatment is done by exposing tool steel material at sub-zero liquid/gas media after heated at austenite temperature. This process significantly affects the martensite phase transformation increase and avoids retained austenite emersion. In particular, the higher martensite volume fraction, the higher hardness and wear resistance value of tool steel. It had been proven that adjusting critical process parameters of cryogenic treatment …

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Effect Of Seawater And Temperature Upon Carbon Fiber/Vinyl Ester (Cfve) Composites And Its Constituents, Vivek Chawla Dec 2023

Effect Of Seawater And Temperature Upon Carbon Fiber/Vinyl Ester (Cfve) Composites And Its Constituents, Vivek Chawla

Doctoral Dissertations

An experimental and computational investigation has been carried out to: (1) develop micromechanical characterization techniques for polymeric composites and (2) evaluate the effects of seawater and temperature upon the micro- and macro-response of the carbon fiber vinyl ester composites (CF/VE). Compression properties degradation due to short-term and long-term exposure to seawater is evaluated. A 12-16 % reduction in compression strength is observed due to long-term exposure to seawater, which is attributed to a decrease in interfacial shear strength (IFSS) due to long-term exposure to seawater. The developed Push-out methodology is used to characterize the IFSS. The presented approach consistently yields …

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Synergistic Strategies In Sinter-Based Material Extrusion (Mex) 3d Printing Of Copper: Process Development, Product Design, Predictive Maps And Models., Kameswara Pavan Kumar Ajjarapu Dec 2023

Synergistic Strategies In Sinter-Based Material Extrusion (Mex) 3d Printing Of Copper: Process Development, Product Design, Predictive Maps And Models., Kameswara Pavan Kumar Ajjarapu

Electronic Theses and Dissertations

3D printing pure copper with high electrical conductivity and exceptional density has long been challenging. While laser-based additive manufacturing technologies suffered due to copper's highly reflective nature towards laser beams, parts printed via binder-assisted technologies failed to reach over 90% IACS (International Annealed Copper Standard), electrical conductivity. Although promising techniques such as binder jetting, filament, and pellet-based 3D printing that can print copper exist, they however still face difficulties in achieving both high sintered densities and electrical conductivity values. This is due to a lack of comprehensive understanding of property evolution from green to sintered states and the strategies that …

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Characterization Of Fcc Al-Cu-Ni-Mn-Ag High Entropy Alloy, Gina Zavala Alvarado Dec 2023

Characterization Of Fcc Al-Cu-Ni-Mn-Ag High Entropy Alloy, Gina Zavala Alvarado

Open Access Theses & Dissertations

The effect of Ag on the microstructure developed in Al-Cu-Ni-Mn alloy has been determined. The modified Al-Cu-Ni-Mn alloy by Ag addition shows the presence of three microconstituents consisting of phases rich in (1) Cu, (2) Ni, and (3) Ag. The foregoing alloys heated for 24 hours from 600 to 1000 °C show excellent oxidation resistance. Oxide formation and microstructural changes of the alloy have been characterized by elemental mapping and X-ray diffraction (XRD). Results show that the elements of Al and Mn preferentially oxidize while Cu and Ni provide oxidation resistance to the alloy. Hardness was taken on the alloy …

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Grain Boundary And Texture Evolution Of Tib/Ti–2al–6sn Titanium Matrix Composite Under Electroshocking Treatment, Yaya Wu, Yan Wen, Anan Guo, Jian Zhou, Fei Yin, Lechun Xie, Liqiang Wang, Lin Hua, Weijie Lu, Lai-Chang Zhang Nov 2023

Grain Boundary And Texture Evolution Of Tib/Ti–2al–6sn Titanium Matrix Composite Under Electroshocking Treatment, Yaya Wu, Yan Wen, Anan Guo, Jian Zhou, Fei Yin, Lechun Xie, Liqiang Wang, Lin Hua, Weijie Lu, Lai-Chang Zhang

Research outputs 2022 to 2026

This work used electroshocking treatment (EST) plus external loading to regulate the microstructure of titanium matrix composites (TMCs). The external loading was 0.3 MPa. After EST plus external loading with 0.3 MPa, the was reduced to 2.53 m in size. The percentage of high angle grain boundaries (HAGBs) in increased first and then decreased. The percent of HAGBs in TiB decreased, mainly due to the introduction of abundant dislocations in the TiB/matrix interface after EST. After EST, the maximum texture strength of TiB decreased from 13.09 to 12.97, and that of decreased from 3.11 to 1.58. After EST under external …

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Strength Deterioration Characteristics Of Lime-Metakaolin Improved Earthen Site Soil Under Freeze-Thaw Cycles, Xin-Ming Li, Hao-Yang Zhang, Di Wu, Yan-Rui Guo, Ke-Bin Ren, Yun-Zhi Tan Oct 2023

Strength Deterioration Characteristics Of Lime-Metakaolin Improved Earthen Site Soil Under Freeze-Thaw Cycles, Xin-Ming Li, Hao-Yang Zhang, Di Wu, Yan-Rui Guo, Ke-Bin Ren, Yun-Zhi Tan

Rock and Soil Mechanics

The Central Plains are located in an area that experiences seasonal freeze-thaw cycles, which can have significant effects on the soil structure of soil relics. To determine if lime-metakaolin (L-MK) is a feasible alternative to natural hydraulic lime (NHL) for earth site restoration work, tests were conducted using lime, metakaolin and silty sand from the site as main raw materials. Mass loss, unconfined compressive strength and splitting tensile strength tests were carried out on L-MK improved silty sand soil undergoing different numbers of freeze-thaw cycles to study its strength characteristics in depth. X-ray diffraction (XRD) thermogravimetry (TG), and scanning electron …

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Mechanism Underlying Effect Of Expansive Agent And Shrinkage Reducing Admixture On Mechanical Properties And Fiber-Matrix Bonding Of Fiber-Reinforced Mortar, Kamran Aghaee, Taihao Han, Aditya Kumar, Kamal Khayat Oct 2023

Mechanism Underlying Effect Of Expansive Agent And Shrinkage Reducing Admixture On Mechanical Properties And Fiber-Matrix Bonding Of Fiber-Reinforced Mortar, Kamran Aghaee, Taihao Han, Aditya Kumar, Kamal Khayat

Materials Science and Engineering Faculty Research & Creative Works

Expansive agent (EA) and shrinkage reducing admixture (SRA) are utilized to reduce shrinkage and risk of cracking in concrete. EA compensates shrinkage by initial expansion, and SRA reduces surface tension in the pore fluid. Although EA and SRA effectively reduce shrinkage, they can impair micro-structure of concrete at high contents. The shrinkage reduction effect of EA and SRA is well known; however, there is limited knowledge about their negative effect on microstructure and fiber matrix interfacial transition zone (ITZ). The current study explores the effect of using 10 % CaO-based EA, 2 % SRA, and their combination on mechanical, shrinkage, …

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Investigation Of Deformation Behavior Of Additively Manufactured Aisi 316l Stainless Steel With In Situ Micro-Compression Testing, Fei Teng, Ching-Heng Shiau, Cheng Sun, Robert C. O'Brien, Michael D. Mcmurtrey Sep 2023

Investigation Of Deformation Behavior Of Additively Manufactured Aisi 316l Stainless Steel With In Situ Micro-Compression Testing, Fei Teng, Ching-Heng Shiau, Cheng Sun, Robert C. O'Brien, Michael D. Mcmurtrey

Materials Science and Engineering Faculty Publications and Presentations

Additive manufacturing techniques are being used more and more to perform the precise fabrication of engineering components with complex geometries. The heterogeneity of additively manufactured microstructures deteriorates the mechanical integrity of products. In this paper, we printed AISI 316L stainless steel using the additive manufacturing technique of laser metal deposition. Both single-phase and dual-phase substructures were formed in the grain interiors. Electron backscatter diffraction and energy-dispersive X-ray spectroscopy indicate that Si, Mo, S, Cr were enriched, while Fe was depleted along the substructure boundaries. In situ micro-compression testing was performed at room temperature along the [001] orientation. The dual-phase substructures …

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Mechanical Properties Of Sand 3d Printed Rock-Like Samples Based On Different Post-Processing Methods, Wei Tian, Xiao-Hui Wang, Wei Yun, Xu Cheng Aug 2023

Mechanical Properties Of Sand 3d Printed Rock-Like Samples Based On Different Post-Processing Methods, Wei Tian, Xiao-Hui Wang, Wei Yun, Xu Cheng

Rock and Soil Mechanics

3D printing, a rapid prototyping technology, has great potential for applications in laboratory rock tests, but the low strength and stiffness of 3D printed samples have been one of the key problems that need to be addressed. In order to find a way to enhance the strength and stiffness of 3D printed rock-like samples, GS19 sand and furan resin were selected as printing materials, and sand 3D printed rock-like samples were used as research objects. Based on this, the samples were post-processed using three different methods: vacuum infiltration, low-temperature treatment, and combination of infiltration and low-temperature. Uniaxial compression tests were …

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Development And Characterization Of Coal-Based Thermoplastic Composite Material For Sustainable Construction, Haibin Zhang, Wenyu Liao, Genda Chen, Hongyan Ma Aug 2023

Development And Characterization Of Coal-Based Thermoplastic Composite Material For Sustainable Construction, Haibin Zhang, Wenyu Liao, Genda Chen, Hongyan Ma

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The exploitation of coal and the disposal of waste plastic present significant environmental and economic challenges that require sustainable and profitable solutions. In response, we propose a renewable construction composite material of coal-based thermoplastic composite (CTC) that can be made from low-grade coal and plastic waste. We developed and tested the hot-press fabrication method for this CTC, using coal with a maximum particle size of 4.75 mm and recycled high-density polyethylene (HDPE). The effects of the coal fraction (50–80 wt.%) on compressive properties, thermal properties, microstructure, and ecological and economic efficiencies of the CTC were investigated. Test results revealed that …

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Twin-Solute, Twin-Dislocation And Twin-Twin Interactions In Magnesium, Materials Yue, Jian Wang, Jian-Feng Nie Jul 2023

Twin-Solute, Twin-Dislocation And Twin-Twin Interactions In Magnesium, Materials Yue, Jian Wang, Jian-Feng Nie

Department of Mechanical and Materials Engineering: Faculty Publications

Magnesium alloys have received considerable research interest due to their lightweight, high specific strength and excellent castability. However, their plastic deformation is more complicated compared to cubic materials, primarily because their low-symmetry hexagonal closepacked (hcp) crystal structure. Deformation twinning is a crucial plastic deformation mechanism in magnesium, and twins can affect the evolution of microstructure by interacting with other lattice defects, thereby affecting the mechanical properties. This paper provides a review of the interactions between deformation twins and lattice defects, such as solute atoms, dislocations and twins, in magnesium and its alloys. This review starts with interactions between twin boundaries …

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Effect Of Internal Curing And Shrinkage-Mitigating Materials On Microstructural Characteristics Of Fiber-Reinforced Mortar, Kamran Aghaee, Kamal Khayat Jul 2023

Effect Of Internal Curing And Shrinkage-Mitigating Materials On Microstructural Characteristics Of Fiber-Reinforced Mortar, Kamran Aghaee, Kamal Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Internal curing (IC) and other shrinkage mitigating materials are employed to reduce shrinkage and risk of cracking. This study investigates the efficiency of individual versus combined use of IC and shrinkage mitigating materials on key characteristics of fiber-reinforced mortar (FRM). The investigated mixtures include a 25% pre-saturated lightweight sand (LWS) that is added individually and combined with 10% CaO-based expansive agent (EA) and 2% shrinkage reducing admixture (SRA). This elucidates the synergistic effect of high content IC and EA/SRA on macro- and micro-mechanical characteristics of FRM, especially at the interface of the matrix with fibers. Mechanical properties, microstructural characteristics, and …

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Microstructural And Mechanical Behavior Investigations Of Nb-Reinforced Mg–Sn–Al–Zn–Mn Matrix Magnesium Composites, Ali Ercetin, Özgür Özgün, Kubilay Aslantaş, Oguzhan Der, Bekir Yalçın, Ercan Şimşir, Muhammad Aamir Jun 2023

Microstructural And Mechanical Behavior Investigations Of Nb-Reinforced Mg–Sn–Al–Zn–Mn Matrix Magnesium Composites, Ali Ercetin, Özgür Özgün, Kubilay Aslantaş, Oguzhan Der, Bekir Yalçın, Ercan Şimşir, Muhammad Aamir

Research outputs 2022 to 2026

This research focuses on the fabrication and characterization of TAZ532-xNb composites, employing high-purity, micron-sized powders of Mg, Sn, Al, Zn, Mn, and Nb as the raw materials. These powders were subjected to a paraffin coating process aimed at mitigating oxidation. The formation of composites was achieved via hot pressing and was followed by surface preparation and analysis using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). An X-ray diffraction (XRD) study was conducted to identify the microstructural phases. Quantitative assessments including the theoretical density, actual density, and relative density were computed, and their fluctuations in relation to the increasing Nb …

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Optimization Of Porosity In Cold Spray Produced Copper And Zinc Coatings, Cameron Hughes May 2023

Optimization Of Porosity In Cold Spray Produced Copper And Zinc Coatings, Cameron Hughes

Graduate Theses & Non-Theses

Since its invention in 1981, the cold spray (CS) additive manufacturing (AM) process has been studied and optimized to produce well-adhered, dense material coatings. CS can operate at a wide range of temperatures if the feed material remains in a solid state. Copper and zinc were studied to characterize and understand the effects of heating element voltage, travel speed, and standoff distance on deposit porosity, grain size, microhardness, and coating thickness. Samples were sprayed on 3.2 mm x 25 mm x 150 mm 6061 aluminum substrates. Sections were taken from the middle of the samples to represent steady-state conditions. Sample …

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Experimen On Mechanical Properties Of Various Graded Collapse Column Fills, Liu Weitao, Du Yanhui, Pang Lifu, Meng Xiangxi, Shen Jianjun, Hu Yingying Apr 2023

Experimen On Mechanical Properties Of Various Graded Collapse Column Fills, Liu Weitao, Du Yanhui, Pang Lifu, Meng Xiangxi, Shen Jianjun, Hu Yingying

Coal Geology & Exploration

In order to study the mechanical properties of collapse column fill under different consolidation pressures and grain compositions. Base on similar simulated rock-soil mass sample under different states of geotechinal consolidation test preparing, we investigated the mechanical characteristics and microstructure evolution mechanism of collapse column filling by conducting the triaxial loading test, mercury intrusion porosimetry and scanning electron microscopy in different states of rock-soil mass. The results show that the rock-soil mass has obvious shaping characteristics and the stress-strain curve can be divided into four stages: pore compaction stage, stable deformation stage, deformation failure stage and creep-like stage. The compressive …

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Characteristics And Formation Mechanisms Of Microstructures In Coal Treated With Co2 Phase Transition Fracturing, Cao Yunxing, Zhang Xinsheng, Zhang Junsheng, Guo Shuaifang, Meng Bingbing Apr 2023

Characteristics And Formation Mechanisms Of Microstructures In Coal Treated With Co2 Phase Transition Fracturing, Cao Yunxing, Zhang Xinsheng, Zhang Junsheng, Guo Shuaifang, Meng Bingbing

Coal Geology & Exploration

CO2 phase transition fracturing (CPTF) is a newly developed technique for coal mine gas control and is characterized by high efficiency, high coal seam permeability, a high gas drainage rate, and outburst elimination. The core of CPTF is reinforced fracturing and the pressure-relief and permeability-enhancement effects of coal seams under high-pressure dynamic loading. Nevertheless, there is a lack of studies on the morphological characteristics and formation mechanisms of newly formed fractures. Current observation and description of the underground fractures on a centimeter-meter scale primarily aim to reveal the fracturing and permeability-enhancement mechanisms of low-permeability coal seams. However, the study …

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A High-Strength Precipitation Hardened Cobalt-Free High-Entropy Alloy, Matthew Luebbe, Jiaqi Duan, Fan Zhang, Jonathan Poplawsky, Hans Pommeranke, Maalavan Arivu, Andrew Hoffman, Mario F. Buchely, Haiming Wen Apr 2023

A High-Strength Precipitation Hardened Cobalt-Free High-Entropy Alloy, Matthew Luebbe, Jiaqi Duan, Fan Zhang, Jonathan Poplawsky, Hans Pommeranke, Maalavan Arivu, Andrew Hoffman, Mario F. Buchely, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

Recent Studies on Precipitation-Hardened High-Entropy Alloys (HEAs) Demonstrate their High Strength and Thermal Stability, Making Them Promising Materials for High-Temperature Structural Applications Such as Nuclear Reactors. However, Many Existing HEAs Contain Cobalt (Co), Which is Unsuitable for Nuclear Applications Because of the Long-Term Activation Issue of Co. Co is Also Expensive and Considered a Critical Material for Other Applications. Therefore, It is Desired to Exclude Co from the Composition. a Co-Free (Fe0.3Ni0.3Mn0.3Cr0.1)88Ti4Al8 HEA Was Developed and Studied in This Work. in Contrast to Previous Co-Free HEAs, This Alloy is …

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Crystalline–Amorphous Nanostructures: Microstructure, Property And Modelling, Binqiang Wei, Lin Li, Lin Shao, Jian Wang Apr 2023

Crystalline–Amorphous Nanostructures: Microstructure, Property And Modelling, Binqiang Wei, Lin Li, Lin Shao, Jian Wang

Department of Mechanical and Materials Engineering: Faculty Publications

Crystalline metals generally exhibit good deformability but low strength and poor irradiation tolerance. Amorphous materials in general display poor deformability but high strength and good irradiation tolerance. Interestingly, refining characteristic size can enhance the flow strength of crystalline metals and the deformability of amorphous materials. Thus, crystalline–amorphous nanostructures can exhibit an enhanced strength and an improved plastic flow stability. In addition, high-density interfaces can trap radiation-induced defects and accommodate free volume fluctuation. In this article, we review crystalline–amorphous nanocomposites with characteristic microstructures including nanolaminates, core–shell microstructures, and crystalline/amorphous-based dual-phase nanocomposites. The focus is put on synthesis of characteristic microstructures, deformation …

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Physics-Based Crystal Plasticity Model For Predicting Microstructure Evolution And Dislocation Densities, Juyoung Jeong Mar 2023

Physics-Based Crystal Plasticity Model For Predicting Microstructure Evolution And Dislocation Densities, Juyoung Jeong

LSU Doctoral Dissertations

This work presents three different studies investigating plastic deformation mechanisms in metals and alloys using crystal plasticity finite element (CPFE) modeling. The first study presents a new nonlocal crystal plasticity model for face-centered cubic single crystals under heterogeneous inelastic deformation. The model incorporates generalized constitutive relations that incorporate the thermally activated and drag mechanisms to cover different kinetics of viscoplastic flow in metals and describes the plastic flow and yielding of single-crystals using dislocation densities. The model is compared to micropillar compression experiments for copper single crystals and clarifies the complex microstructural evolution of dislocation densities in metals. The second …

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Enhancement Of Heat-Cured Cement Paste With Tannic Acid, Jinrui Zhang, Ziye Kang, Youzhi Yang, Biqin Dong, Hongyan Ma Mar 2023

Enhancement Of Heat-Cured Cement Paste With Tannic Acid, Jinrui Zhang, Ziye Kang, Youzhi Yang, Biqin Dong, Hongyan Ma

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Improvement of Cement-Based Materials' Performance by Natural Organic Compounds Can Greatly Promote the Green and Sustainable Development of the Construction Industry. However, Such Compounds Are Not Widely Used Yet Because of their Retarding Effect on Cement. in This Study, the Retardation Effect of Tannic Acid (TA, a Well-Known Retarding Compound) is overcome and the Enhancing Effect is Achieved by Adding Less Than 0.1% Content and Curing Samples in Thermal Regime. Then the Mechanism of TA Enhancing Heat-Cured Cement Pastes is Studied Systematically. Mechanical Properties Results Suggest that Addition of 0.025% TA Can Reduce the Compressive and Flexural Strengths of …

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Synergistic Effect Of Hedp.4na And Different Induced Pouring Angles On Mechanical Properties Of Fiber-Reinforced Alkali-Activated Slag Composites, Jingjie Wei, Jianwei Liu, Kamal Khayat, Wu Jian Long Mar 2023

Synergistic Effect Of Hedp.4na And Different Induced Pouring Angles On Mechanical Properties Of Fiber-Reinforced Alkali-Activated Slag Composites, Jingjie Wei, Jianwei Liu, Kamal Khayat, Wu Jian Long

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Poor Flexural and Damping Properties of Building Materials Damages Concrete Structures and Affects their Service Life When Concrete Structures Are Subjected to Dynamic Loads. Three Different Dosages (I.e., 0%, 0.3%, and 0.6%) of Organic Phosphonates (HEDP.4Na) and Different Pouring Methods (I.e., Conventional Pouring Method, 90°-Induced Pouring Method, and 150°-Induced Pouring Method) Were Designed to Improve the Flexural and Damping Performance of Fiber-Reinforced Alkali-Activated Slag Composites (FR-AASC). the Enhanced Mechanism of HEDP.4Na Was Revealed by Phase Analysis (X-Ray Diffraction, XRD), Pore Structure Analysis (Mercury Intrusion Porosimetry, MIP), the Heat of Hydration, and Scanning Electron Microscopy (SEM) Analysis. the Results Showed …

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Synthesizing Ti–Ni Alloy Composite Coating On Ti–6al–4v Surface From Laser Surface Modification, Yitao Chen, Joseph William Newkirk, Frank W. Liou Feb 2023

Synthesizing Ti–Ni Alloy Composite Coating On Ti–6al–4v Surface From Laser Surface Modification, Yitao Chen, Joseph William Newkirk, Frank W. Liou

Materials Science and Engineering Faculty Research & Creative Works

In This Work, a Ni-Alloy Deloro-22 Was Laser-Deposited on a Ti–6Al–4V Bar Substrate with Multiple Sets of Laser Processing Parameters. the Purpose Was to Apply Laser Surface Modification to Synthesize Different Combinations of Ductile TiNi and Hard Ti2Ni Intermetallic Phases on the Surface of Ti–6Al–4V in Order to Obtain Adjustable Surface Properties. Scanning Electron Microscopy, Energy Dispersion Spectroscopy, and X-Ray Diffraction Were Applied to Reveal the Deposited Surface Microstructure and Phase. the Effect of Processing Parameters on the Resultant Compositions of TiNi and Ti2Ni Was Discussed. the Hardness of the Deposition Was Evaluated, and Comparisons with …

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Effect Of Additional Water Or Superplasticizer On Key Characteristics Of Cement Paste Made With Superabsorbent Polymer And Other Shrinkage Mitigating Materials, Kamran Aghaee, Ricarda Sposito, Karl Christian Thienel, Kamal Khayat Feb 2023

Effect Of Additional Water Or Superplasticizer On Key Characteristics Of Cement Paste Made With Superabsorbent Polymer And Other Shrinkage Mitigating Materials, Kamran Aghaee, Ricarda Sposito, Karl Christian Thienel, Kamal Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The use of superabsorbent polymer (SAP) coupled with expansive agent (EA) or shrinkage-reducing admixture (SRA) can effectively reduce shrinkage of cement-based materials. However, SAP particles at high contents can adversely affect rheological and mechanical properties. Securing proper workability can be accomplished by additional water or adjusting the superplasticizer (SP) demand. There is an uncertainty about the efficiency of these approaches to workability compensation. This study evaluates the effect of additional water or SP on key properties of cement paste made with SAP and relatively high content of EA or SRA. Macro and micro mechanisms underlying the effect of combined shrinkage …

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Boro/Carbothermal Reduction Co-Synthesis Of Dual-Phase High-Entropy Boride-Carbide Ceramics, Lun Feng, William Fahrenholtz, Gregory E. Hilmas, Stefano Curtarolo Jan 2023

Boro/Carbothermal Reduction Co-Synthesis Of Dual-Phase High-Entropy Boride-Carbide Ceramics, Lun Feng, William Fahrenholtz, Gregory E. Hilmas, Stefano Curtarolo

Materials Science and Engineering Faculty Research & Creative Works

Dense, dual-phase (Cr,Hf,Nb,Ta,Ti,Zr)B2-(Cr,Hf,Nb,Ta,Ti,Zr)C ceramics were synthesized by boro/carbothermal reduction of oxides and densified by spark plasma sintering. The high-entropy carbide content was about 14.5 wt%. Grain growth was suppressed by the pinning effect of the two-phase ceramic, which resulted in average grain sizes of 2.7 ± 1.3 µm for the high-entropy boride phase and 1.6 ± 0.7 µm for the high-entropy carbide phase. Vickers hardness values increased from 25.2 ± 1.1 GPa for an indentation load of 9.81 N to 38.9 ± 2.5 GPa for an indentation load of 0.49 N due to the indentation size effect. Boro/carbothermal …

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On The Permittivity Of Xt-Cf20, Aaron Harmon, Wei Zhang, Victor Khilkevich Jan 2023

On The Permittivity Of Xt-Cf20, Aaron Harmon, Wei Zhang, Victor Khilkevich

Electrical and Computer Engineering Faculty Research & Creative Works

In This Work, the Permittivity of a 3D-Printed Carbon Fiber-Loaded Anisotropic Material, XT-CF20, is Examined Further. the Microstructure of XT-CF20 is First Examined Via Optical Imaging and is Shown to Be Composed of Inclusions that Are Aligned with the Print Direction of the Sample. the Permittivity Tensor for the Aligned Microstructure is Then Measured using a Capacitive Measurement Technique and Simulations Are Provided to Demonstrate the Validity of This Measurement Method. the Simulated Permittivity Values for XT-CF20 Samples with Varying Infill Structures Are Then Presented and Compared to the Measured Permittivity Values of Said Samples. an Error of Less Than …

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Laser Powder Bed Fusion Process, Structure, And Properties: Holistic Approach To Establishing Metallurgical Quality, Hunter Taylor Dec 2022

Laser Powder Bed Fusion Process, Structure, And Properties: Holistic Approach To Establishing Metallurgical Quality, Hunter Taylor

Open Access Theses & Dissertations

The advent of metal additive manufacturing (AM) was posed as a disruption to casting, forging, machining, and forming with the notion "complexity is free". However, since invention in the late 1990's the marketed potential has not been realized. Metal based AM is best viewed from the process-structure-properties-performance (PSPP) paradigm taught in material science and engineering, which links the process history to the part performance. Understanding the complex and localized process control made available by AM creates a significant challenge in defining the materials structure, properties, and performance. The lack of holistic understating of inputs and corresponding results has been identified …

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Soil-Water Characteristic Of Biochar-Clay Mixture In The Full Suction Range, Ming-Yu Li, Wen-Jing Sun, Qiang Huang, De-An Sun Nov 2022

Soil-Water Characteristic Of Biochar-Clay Mixture In The Full Suction Range, Ming-Yu Li, Wen-Jing Sun, Qiang Huang, De-An Sun

Rock and Soil Mechanics

Soil-water characteristic curve (SWCC) plays an important role in defining the hydro-mechanical behavior of unsaturated soils. Biochar has the properties of porous structure, high specific surface area and high adsorption. The hydraulic characteristics of biochar-amended soil may change due to the influence of natural environmental factors when applied as the cover layer of landfills. In order to study the effect of biochar content on the water retention behavior of biochar-clay mixture in full suction range, the suction of samples was controlled by vapor equilibrium technique (suction range 3–368 MPa), filter paper method (suction range 0–40 MPa) and pressure plate method …

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