Open Access. Powered by Scholars. Published by Universities.®

Materials Science and Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 3271 - 3300 of 16386

Full-Text Articles in Materials Science and Engineering

Effect Of Mechanical Activation On Carbothermal Synthesis And Densification Of Zrc, Nina Obradović, Lun Feng, Suzana Filipović, Miljana Mirković, Darko Kosanović, Jelena Rogan, William Fahrenholtz Jan 2023

Effect Of Mechanical Activation On Carbothermal Synthesis And Densification Of Zrc, Nina Obradović, Lun Feng, Suzana Filipović, Miljana Mirković, Darko Kosanović, Jelena Rogan, William Fahrenholtz

Materials Science and Engineering Faculty Research & Creative Works

Zirconium carbide ceramics were prepared by carbothermal reduction of ZrO2 and C that were mixed by high-energy ball milling. Powders were milled for times from 0 to 120 min in air. As milling time increased, the surface area of the powders increased, indicating significant particle size reduction. Milled powders were reacted at 1600 °C and then densified by spark plasma sintering at 2000 °C, which was sufficient to convert the starting powders to zirconium carbide. Unmilled powders did not reach full density. Milled powders reached full density, but ZrO2 impurities were found for specimens prepared from powders milled …

Go to article

Additive Manufacturing Of (Mgconicuzn)O High-Entropy Oxide Using A 3d Extrusion Technique And Oxide Precursors, Ruoyu Chen, Saisai Li, Qingfeng Yan, Haiming Wen Jan 2023

Additive Manufacturing Of (Mgconicuzn)O High-Entropy Oxide Using A 3d Extrusion Technique And Oxide Precursors, Ruoyu Chen, Saisai Li, Qingfeng Yan, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

This report presents an additive manufacturing approach, for the first time, to producing high-entropy oxides (HEOs) using a 3D extrusion-based technique with oxide precursors. The precursors were prepared by a wet chemical method from sulfates. Additives were utilized to optimize the rheological properties of the printing inks with these precursors, and the properties of the printed HEOs were improved by increasing the solid content of the inks. When ink with a solid content of 78 wt% was used for printing, the resulting HEO exhibited a relative density of 92% and a high dielectric constant after undergoing pressure less sintering at …

Go to article

High-Temperature Interactions Between Titanium Alloys And Strontium Zirconate Refractories, R. Sharon Uwanyuze, Baris Yavas, Jiyao Zhang, Janos E. Kanyo, Lesley D. Frame, Rainer J. Hebert, Stefan Schafföner, S. Pamir Alpay Jan 2023

High-Temperature Interactions Between Titanium Alloys And Strontium Zirconate Refractories, R. Sharon Uwanyuze, Baris Yavas, Jiyao Zhang, Janos E. Kanyo, Lesley D. Frame, Rainer J. Hebert, Stefan Schafföner, S. Pamir Alpay

Materials Science and Engineering Faculty Research & Creative Works

We investigated interactions between Ti6Al4V alloys and strontium zirconate (SrZrO3) ceramic to assess its potential as a refractory mold material in investment casting. We developed a robust yet simple procedure to examine both the liquid–solid and solid–solid interactions using pellets in drop casting and diffusion couple methods. Reaction layers were characterized using optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray diffraction (XRD). The results were compared to alumina (Al2O3) which is still a common refractory ceramic for molds in investment casting. Our findings indicate that Ti6Al4V surfaces in contact with …

Go to article

Strength Retention Of Single-Phase High-Entropy Diboride Ceramics Up To 2000°C, Lun Feng, William Fahrenholtz, Gregory E. Hilmas, Yue Zhou, Jincheng Bai Jan 2023

Strength Retention Of Single-Phase High-Entropy Diboride Ceramics Up To 2000°C, Lun Feng, William Fahrenholtz, Gregory E. Hilmas, Yue Zhou, Jincheng Bai

Materials Science and Engineering Faculty Research & Creative Works

The mechanical properties of single-phase (Hf0.2,Nb0.2,Ta0.2,Ti0.2,Zr0.2)B2 ceramics with high purity were investigated. The resulting ceramics had relative density greater than 99%, and an average grain size of 4.3 ± 1.6 μm. At room temperature (RT), the Vickers hardness was 25.2 ± 0.6 GPa at a load of 0.49 N, Young's modulus was 551 ± 7 GPa, fracture toughness was 4.5 ± 0.4 MPa m1/2, and flexural strength was 507 ± 10 MPa. Flexural strength increased by more than 50% from 507 ± 10 MPa at RT to 776 ± …

Go to article

Improving Strength And Microstructure Of Sic Reticulated Porous Ceramic Through In-Situ Generation Of Sic Whiskers Within Hollow Voids, Ruoyu Chen, Kunshi Xie, Haipeng Zhu, Qun He, Saisai Li, Haiming Wen Jan 2023

Improving Strength And Microstructure Of Sic Reticulated Porous Ceramic Through In-Situ Generation Of Sic Whiskers Within Hollow Voids, Ruoyu Chen, Kunshi Xie, Haipeng Zhu, Qun He, Saisai Li, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

SiC Reticulated Porous Ceramic with Excellent Strength and High-Density Ceramic Struts Was Successfully Prepared using the Polymer Replica Method, Followed by Pressureless Sintering under a Buried Charcoal Atmosphere. First, a Polyurethane (PU) Template Was Coated with a Si Slurry and Then a SiC-Containing Slurry, and Subsequently Heated under the Buried Charcoal Atmosphere. to Ensure Excellent Coating Ability of the Slurries, the Viscosity, Thixotropy, and Yield Stresses of the Si Slurry Were Optimized by Adjusting the Content of the Thickening Agent. during Heating, Si in the Coating Layer Reacted with the Residual C and CO Gas from the PU Template and …

Go to article

Phenomenological Analysis Of Surface Degradation Of Metallic Materials In Extreme Environment, Simon N. Lekakh, Oleg Neroslavsky Jan 2023

Phenomenological Analysis Of Surface Degradation Of Metallic Materials In Extreme Environment, Simon N. Lekakh, Oleg Neroslavsky

Materials Science and Engineering Faculty Research & Creative Works

The resistance to surface degradation in metallic alloys plays an important role for the lifetime of the components working in harsh environments. The mechanisms involved in degradation of metallic surface in a high-temperature aggressive gaseous atmosphere include the following: forming adherent to the surface multiphase oxide layer, partial spallation, and possible vaporization of formed compounds. The governing equation, which describes a parabolic growth of adherent layer, time-dependent vaporization, and cross-linked to instantaneous thickness of adherent layer spallation rate, was suggested and analyzed. The several relationships between the kinetic constants were defined from analysis of the governing equation. Design of routes …

Go to article

Real-Time Air Gap And Thickness Measurement Of Continuous Caster Mold Flux By Extrinsic Fabry-Perot Interferometer, Abhishek Prakash Hungund, Hanok Tekle, Bohong Zhang, Ronald J. O'Malley, Jeffrey D. Smith, Rex E. Gerald, Jie Huang Jan 2023

Real-Time Air Gap And Thickness Measurement Of Continuous Caster Mold Flux By Extrinsic Fabry-Perot Interferometer, Abhishek Prakash Hungund, Hanok Tekle, Bohong Zhang, Ronald J. O'Malley, Jeffrey D. Smith, Rex E. Gerald, Jie Huang

Materials Science and Engineering Faculty Research & Creative Works

Mold Flux plays a critical role in continuous casting of steel. Along with many other functions, the mold flux in the gap between the solidifying steel shell and the mold serves as a medium for controlling heat transfer and as a barrier to prevent shell sticking to the mold. This manuscript introduces a novel method of monitoring the structural features of a mold flux film in real-time in a simulated mold gap. A 3-part stainless-steel mold was designed with a 2 mm, 4 mm and, 6 mm step profile to contain mold flux films of varying thickness. An Extrinsic Fabry-Perot …

Go to article

Effect Of Annealing Time On Texture Evolution Of Fe–3.4 Wt% Si Nonoriented Electrical Steel, Yizhou Du, Ronald J. O'Malley, Mario F. Buchely, Paul Kelly Jan 2023

Effect Of Annealing Time On Texture Evolution Of Fe–3.4 Wt% Si Nonoriented Electrical Steel, Yizhou Du, Ronald J. O'Malley, Mario F. Buchely, Paul Kelly

Materials Science and Engineering Faculty Research & Creative Works

Herein, the Effect of Annealing Time on the Texture Evolution in Fe–3.4 Wt.% Si Non-Oriented Electrical Steel is Investigated. Strip Samples Are Cast using a Vacuum Sampling Method, Which Simulate the Solidification Conditions of an Industrial Twin Roll Thin Strip Casting (TRSC) Process. As-Cast Samples with Different Carbon and Sulfur (C&S) Levels Are Hot Rolled (HR) with Varying Levels of Hot Deformation, Cold Rolled (CR) to 0.35 Mm Thickness, and Then Annealed at 1050 °C for Different Holding Times (1, 6, 24 H). to Fe–3.4 Wt.% Si Non oriented Electrical Steel, the Observed Texture Evolution Can Be Divided into Different …

Go to article

Advancing Aluminum Casting Optimization With Real-Time Temperature And Gap Measurements Using Optical Fiber Sensors At The Metal-Mold Interface, Bohong Zhang, Abhishek Prakash Hungund, Dinesh Reddy Alla, Deva Prasaad Neelakandan, Muhammad Roman, Ronald J. O'Malley, Laura Bartlett, Rex E. Gerald, Jie Huang Jan 2023

Advancing Aluminum Casting Optimization With Real-Time Temperature And Gap Measurements Using Optical Fiber Sensors At The Metal-Mold Interface, Bohong Zhang, Abhishek Prakash Hungund, Dinesh Reddy Alla, Deva Prasaad Neelakandan, Muhammad Roman, Ronald J. O'Malley, Laura Bartlett, Rex E. Gerald, Jie Huang

Materials Science and Engineering Faculty Research & Creative Works

Accurate measurement of interfacial heat transfer during casting solidification is crucial for optimizing metal solidification processes. The gap between the mold wall and the casting surface plays a significant role in heat transfer and cooling rates. In this study, two innovative fiber-optic sensors are employed to measure real-time mold gaps and thermal profiles during the solidification of A356 aluminum in a permanent mold casting. The experimental setup consists of a specially designed mold system made of unheated, uncoated tool steel, which facilitates easy installation of the fiber-optic sensors. An Extrinsic Fabry-Perot interferometric (EFPI) sensor is utilized to monitor the evolving …

Go to article

Impact Of Alumina-Based Binder On Formation Of Dense Strontium Zirconate Ceramics, Janos E. Kanyo, R. Sharon Uwanyuze, Jiyao Zhang, Rainer Hebert, Stefan Schafföner, Lesley Frame Jan 2023

Impact Of Alumina-Based Binder On Formation Of Dense Strontium Zirconate Ceramics, Janos E. Kanyo, R. Sharon Uwanyuze, Jiyao Zhang, Rainer Hebert, Stefan Schafföner, Lesley Frame

Materials Science and Engineering Faculty Research & Creative Works

Strontium zirconate (SrZrO3) is a technical ceramic with potential for refractory applications due to its chemical stability at high temperatures, high melting temperature, and favorable thermal expansion coefficient. Practical use of SrZrO3 is limited by poor mechanical strength relative to ceramics such as alumina (Al2O3). Sintering of SrZrO3 with a hydratable Al2O3 binder is investigated as a method for improving mechanical performance. Density, phase composition, thermomechanical properties, and chemical stability in contact with alloys up to 1350 °C are considered. Results are compared with SrZrO3 samples formed using a traditional polyvinyl alcohol (PVA) binder. SrZrO3 reacts with alumina during sintering …

Go to article

Residual Stress Distribution, Distortion, And Crack Initiation In Conventional And Intensive Quench Practices, Kingsley Tochukwu Amatanweze, Mario F. Buchely, Viraj Ashok Athavale, Laura Bartlett, Ronald J. O'Malley, Toshi Suzuki Jan 2023

Residual Stress Distribution, Distortion, And Crack Initiation In Conventional And Intensive Quench Practices, Kingsley Tochukwu Amatanweze, Mario F. Buchely, Viraj Ashok Athavale, Laura Bartlett, Ronald J. O'Malley, Toshi Suzuki

Materials Science and Engineering Faculty Research & Creative Works

This study evaluates the effect of two different quench practices on distortion, sensitivity to quench cracking, development and distribution of residual stress, microstructural uniformity, and hardenability of standardized test castings. Navy C-rings made of AISI 4340 were quenched in this experiment. Some rings were quenched in a conventional draft tube immersion quench bath, and others were quenched in an intensive quench spray system to compare with the results from the conventional immersion quench bath. The rings were measured with a coordinate measuring machine, for distortion and flatness, before and after quenching. Hardness profiles of the quenched rings showed through hardness …

Go to article

Microstructure Evolution And Austenitic Grain Refinement Of Ti-Modified High Mn Steels During Solution Annealing Heat Treatment, Abhinav Karanam, Arnab Sarkar, Erik Nenzen, Viraj Ashok Athavale, Mark Watson, Laura Nicole Bartlett, Lukas Bichler Jan 2023

Microstructure Evolution And Austenitic Grain Refinement Of Ti-Modified High Mn Steels During Solution Annealing Heat Treatment, Abhinav Karanam, Arnab Sarkar, Erik Nenzen, Viraj Ashok Athavale, Mark Watson, Laura Nicole Bartlett, Lukas Bichler

Materials Science and Engineering Faculty Research & Creative Works

Austenitic high manganese (Mn) steels are often used in harsh environments due to their high toughness and wear resistance. Heat treatments are performed to engineer the microstructure of the steels and optimize their performance for the desired service conditions. This study investigated the effect of titanium (Ti) and heat treatment on the microstructure of cast high Mn steel (HMS) alloys. The results reveal that Ti addition contributed to grain refinement in the as cast and heat-treated conditions. In-situ observation of microstructure evolution up to 1125 °C confirmed the stability of precipitated TiC particles, while revealing a new mechanism of grain …

Go to article

Constructing A Fine Dispersion And Chemical Interface Based On An Electrostatic Self-Assembly And Aqueous Phase Compound In Go/Sio2/Sbr Composites To Achieve High-Wear Resistance In Eco-Friendly Green Tires, Rui Zhang, Jiaye Li, Stephen Jerrams, Shui Hu, Shipeng Wen, Ligun Zhang Jan 2023

Constructing A Fine Dispersion And Chemical Interface Based On An Electrostatic Self-Assembly And Aqueous Phase Compound In Go/Sio2/Sbr Composites To Achieve High-Wear Resistance In Eco-Friendly Green Tires, Rui Zhang, Jiaye Li, Stephen Jerrams, Shui Hu, Shipeng Wen, Ligun Zhang

Articles

The hazard to the ecosystem caused by rubber microparticles generated from tire abrasion has been a constant concern. Therefore, to protect this ecosystem, the development of a tire tread with high abrasion resistance is especially significant. Herein, γ-aminopropyltriethoxysilane (APTES) was used to modify graphene oxide (GO) and silica (SiO2) to obtain GO and SiO2 with positive charges (NG and NS). Furthermore, NG and NS were electrostatically self-assembled by using maleic anhydride (MAH) hydrolysis, thereby obtaining composite particles (NG-NS) with “bridged structures”. Also, the NG-NS/styrene butadiene rubber (SBR) compounds possessing fine dispersion of NG-NS were prepared by the aqueous compounding method. …

Go to article

Aerosol Synthesis Of Tungsten Bronze Particles For Nir Shielding, Hao Tu Jan 2023

Aerosol Synthesis Of Tungsten Bronze Particles For Nir Shielding, Hao Tu

Theses and Dissertations

This dissertation emphasizes the need for efficient energy use in buildings and transportation due to global warming and the energy crisis. It suggests that improving energy efficiency can help reduce energy consumption and emissions and support sustainability. The dissertation introduces various transparent materials that can block near-infrared (NIR) radiation from solar radiation to save energy and money, and it highlights the growing market value of such products. The dissertation compares tungsten bronze with other NIR shielding materials and shows its advantages. The dissertation introduces a cheap and environmentally friendly method for continuously producing tungsten bronze particles via aerosol synthesis. Particle …

Go to article

Fabrication And Optical Properties Of Two-Dimensional Transition Metal Dichalcogenides, Manpreet Boora Jan 2023

Fabrication And Optical Properties Of Two-Dimensional Transition Metal Dichalcogenides, Manpreet Boora

Dissertations, Master's Theses and Master's Reports

Two-dimensional layered materials such as graphene and transition metal dichalcogenides have gained a lot of attention because of their distinctive chemical, optical, and electronic properties. Transition metal dichalcogenides can have a tunable bandgap in the range of 1 − 3 eV (visible), which enables their applications in ultrathin field effect transistors, photovoltaics, sensors, and optoelectronic devices. They exhibit an indirect-to-direct band gap transition when thinned down from bulk to a single layer. They show strong photoluminescence, electron–photon interaction, valley pseudospin, nonlinear optical response, and lack of dangling bonds. Many exotic phenomena appear when materials are thinned to nanoscale size because …

Go to article

Study Of Nanocomposite Materials Using Molecular Dynamics, Prashik Sunil Gaikwad Jan 2023

Study Of Nanocomposite Materials Using Molecular Dynamics, Prashik Sunil Gaikwad

Dissertations, Master's Theses and Master's Reports

There is an increase in demand for new lightweight structural materials in the aerospace industry for more efficient and affordable human space travel. Polymer matrix composites (PMCs) with reinforcement material as carbon nanotubes (CNTs) have shown exceptional increase in the mechanical properties. Flattened carbon nanotubes (flCNTs) are a primary component of many carbon nanotube (CNT) yarn and sheet materials, which are promising reinforcements for the next generation of ultra-strong composites for aerospace applications. These flCNT/polymer materials are subjected to extreme pressure and temperature during curing process. Therefore there is a need to investigate the evolution of properties during the curing …

Go to article

Comparison Of The Thermal Stability In Equal-Channel-Angular-Pressed And High-Pressure-Torsion-Processed Fe–21cr–5al Alloy, Maalavan Arivu, Andrew Hoffman, Jiaqi Duan, Jonathan Poplawsky, Xinchang Zhang, Frank W. Liou, Rinat Islamgaliev, Ruslan Valiev, Haiming Wen Jan 2023

Comparison Of The Thermal Stability In Equal-Channel-Angular-Pressed And High-Pressure-Torsion-Processed Fe–21cr–5al Alloy, Maalavan Arivu, Andrew Hoffman, Jiaqi Duan, Jonathan Poplawsky, Xinchang Zhang, Frank W. Liou, Rinat Islamgaliev, Ruslan Valiev, Haiming Wen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Nanostructured Steels Are Expected to Have Enhanced Irradiation Tolerance and Improved Strength. However, They Suffer from Poor Microstructural Stability at Elevated Temperatures. in This Study, Fe–21Cr–5Al–0.026C (Wt%) Kanthal D (KD) Alloy Belonging to a Class of (FeCrAl) Alloys Considered for Accident-Tolerant Fuel Cladding in Light-Water Reactors is Nanostructured using Two Severe Plastic Deformation Techniques of Equal-Channel Angular Pressing (ECAP) and High-Pressure Torsion (HPT), and their Thermal Stability between 500–700 °C is Studied and Compared. ECAP KD is Found to Be Thermally Stable Up to 500 °C, Whereas HPT KD is Unstable at 500 °C. Microstructural Characterization Reveals that ECAP KD …

Go to article

Microstructure, Mechanical Properties And Oxidation Behavior Of Refractory Multi-Principal Element Alloys By Laser Remelting And Conventional Manufacturing, Visharad Jalan, Seth Crawford, Sung Heng Wu, Frank W. Liou, Haiming Wen Jan 2023

Microstructure, Mechanical Properties And Oxidation Behavior Of Refractory Multi-Principal Element Alloys By Laser Remelting And Conventional Manufacturing, Visharad Jalan, Seth Crawford, Sung Heng Wu, Frank W. Liou, Haiming Wen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Refractory Multi-Principal Element Alloys (RMPEAs), HfNbTaTiZr, (HfNbTaTiZr)9Cr, and (HfNbTaTiZr)9Al, Were Manufactured using Vacuum Arc Melting Followed by Laser Remelting to Mimic Additive Manufacturing. the Microhardness of the As-Cast HfNbTaTiZr, (HfNbTaTiZr)9Cr, and (HfNbTaTiZr)9Al Samples after Arc Melting Was Measured as 6.20, 7.63, and 6.89 Gpa, respectively. after Laser Remelting and Re-Solidification, the Hardness Increased by ~ 30% for Each Composition; the Hardest Was (HfNbTaTiZr)9Cr Measured at 9.60 GPa, While the Softest Was HfNbTaTiZr with a Hardness of 8.42 GPa, Which Was Still Harder Compared to All the Other Samples. the Addition …

Go to article

Correction: Modeling Phase Selection And Extended Solubility In Rapid Solidified Alloys (Metallurgical And Materials Transactions A, (2023), 10.1007/S11661-023-07221-7), Azeez Akinbo, Yijia Gu Jan 2023

Correction: Modeling Phase Selection And Extended Solubility In Rapid Solidified Alloys (Metallurgical And Materials Transactions A, (2023), 10.1007/S11661-023-07221-7), Azeez Akinbo, Yijia Gu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In the original online version of this article the reference citation in Fig. 3b was incorrect. The original article was corrected.

Go to article

Preparation, Cure, And Characterization Of Cyanate Ester-Epoxy Blends Containing Reactive Flame Retardants, Mustafa Mukhtar, Donald A. Klosterman Jan 2023

Preparation, Cure, And Characterization Of Cyanate Ester-Epoxy Blends Containing Reactive Flame Retardants, Mustafa Mukhtar, Donald A. Klosterman

Chemical and Materials Engineering Faculty Publications

Cyanate ester resins are sometimes mixed with lower cost epoxy monomers to modify cost, toughness, and processing capabilities. Despite the high performance of these thermosetting polymers, flame retardancy remains an issue. This study examined blends of three different commercial cyanate ester monomers (LVT-100, LECy, and XU-71787.02) and diglycidyl ether of bisphenol A (DGEBA) at 50/50 wt% of each type. The blends were successfully reacted with two reactive flame retardants (FR): 9,10-dihydro-9-ox-9-phosphaphenanthrene-10-oxide (DOPO) and poly(m-phenylene methylphosphonate) (PMP) at phosphorus contents ranging from 0 to 3 wt%. The curing behavior of EP/CE blends was investigated using differential scanning calorimetry (DSC). It was …

Go to article

การเตรียมและประสิทธิภาพการเร่งปฏิกิริยาเชิงแสงของวัสดุเชิงประกอบสตรอนเชียมไททาเนตที่เจือด้วยอะลูมิเนียม/กราฟิติกคาร์บอนไนไตรด์ภายใต้แสงที่ตามองเห็น, ณัฐรุจา โตวิรัตน์กิจ Jan 2023

การเตรียมและประสิทธิภาพการเร่งปฏิกิริยาเชิงแสงของวัสดุเชิงประกอบสตรอนเชียมไททาเนตที่เจือด้วยอะลูมิเนียม/กราฟิติกคาร์บอนไนไตรด์ภายใต้แสงที่ตามองเห็น, ณัฐรุจา โตวิรัตน์กิจ

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีวัตถุประสงค์เพื่อเตรียมตัวเร่งปฏิกิริยาเชิงแสงของวัสดุเชิงประกอบสตรอนเชียมไททาเนตที่เจือด้วยอะลูมิเนียม/กราฟิติกคาร์บอนไนไตรด์ (Al-SrTiO3/g-C3N4) สำหรับการย่อยสลายสีย้อมโรดามีนบีและการผลิตแก๊สไฮโดรเจนจากกระบวนการแยกน้ำภายใต้การฉายแสงที่ตามองเห็น โดย SrTiO3 เตรียมด้วยวิธีปฏิกิริยาสถานะของแข็งที่อุณหภูมิ 1300 °C เป็นเวลา 12 ชั่วโมง จากนั้นนำ SrTiO3 มาเจือด้วยอะลูมิเนียม 2% โดยโมล โดยการเติมผงอะลูมินา (Al2O3) ผ่านกระบวนการฟลักซ์ด้วยการเติมเกลือสตรอนเซียมคลอไรด์ (SrCl2) ในเบ้าหลอมอะลูมินาที่อุณหภูมิ 1150 °C เป็นเวลา 10 ชั่วโมง พบว่า Al-SrTiO3 ที่ผ่านการบำบัดด้วยฟลักซ์แสดงประสิทธิภาพการย่อยสลายสีย้อมโรดามีนบีที่ดีขึ้นภายใต้แสงยูวีเมื่อเทียบกับ SrTiO3 ที่ไม่ได้ผ่านการบำบัด โดย Al-SrTiO3 ที่ผ่านการบำบัดด้วยฟลักซ์มีประสิทธิภาพการย่อยสลายสีย้อม 21.66% หลังจาก 60 นาที ซึ่งสูงกว่าประสิทธิภาพ 3.1% ของ SrTiO3 ที่สังเคราะห์โดยวิธีปฏิกิริยาสถานะของแข็งถึงเจ็ดเท่า การปรับปรุงนี้เกิดจากการบำบัดด้วยฟลักซ์ที่ช่วยเพิ่มความเป็นผลึกและส่งเสริมการแทรกตัวของ Al3+ ในโครงสร้างเพอรอฟสไกต์ของ SrTiO3 รวมถึงการสร้างตำหนิช่องว่างของออกซิเจนและลดการเกิด Ti3+ ที่เป็นอุปสรรคต่อกระบวนการเร่งปฏิกิริยาเชิงแสง จากนั้นนำ Al-SrTiO3 ที่ได้มาเตรียมวัสดุเชิงประกอบ Al-SrTiO3/g-C3N4 (5% Al-SrTiO3) ด้วยวิธีต่าง ๆ พบว่าวิธีการเผาแคลไซน์ร่วมแสดงประสิทธิภาพการย่อยสลายสีย้อมโรดามีนบีภายใต้แสงที่ตามองเห็นสูงที่สุด เมื่อเปรียบเทียบกับการเตรียมด้วยวิธีการบดผสมเชิงกล วิธีการกระจายในตัวกลาง และวิธีไฮโดรเทอร์มอล เนื่องจากวิธีการเผาแคลไซน์ร่วมทำให้ได้พื้นที่ผิวจำเพาะที่สูงขึ้น ซึ่งช่วยเพิ่มการดูดซับและการย่อยสลายสีย้อม รวมทั้งลดการรวมตัวของอิเล็กตรอนและโฮล อย่างไรก็ตามวัสดุเชิงประกอบ Al-SrTiO3/g-C3N4 ยังแสดงประสิทธิภาพการย่อยสลายสีย้อมโรดามีนบีภายใต้แสงที่ตามองเห็นต่ำกว่า g-C3N4 บริสุทธิ์เล็กน้อย ในการทดสอบประสิทธิภาพการผลิตแก๊สไฮโดรเจนของ Al-SrTiO3 ภายใต้แสงยูวีเมื่อเติมตัวเร่งปฏิกิริยาร่วมโรเดียมโครเมียมออกไซด์ (RhCrOx) 0.1% โดยน้ำหนัก พบว่า อัตราการผลิตแก๊สไฮโดรเจนเท่ากับ 568 ไมโครโมลต่อกรัมต่อชั่วโมง และเมื่อเติมไตรเอทาโนลามีน (triethanolamine, TEOA) เป็นสารเอื้อให้เกิดปฏิกิริยาเพื่อจับโฮลในแถบวาเลนซ์ อัตราการผลิตไฮโดรเจนเพิ่มขึ้นเป็น 826 ไมโครโมลต่อกรัมต่อชั่วโมง เนื่องจากอิเล็กตรอนสามารถเข้าร่วมในปฏิกิริยารีดักชันได้มากขึ้น เมื่อนำวัสดุเชิงประกอบ Al-SrTiO3/g-C3N4 ที่เตรียมด้วยวิธีการเผาแคลไซน์ร่วมที่สัดส่วนต่าง ๆ และเติมตัวเร่งปฏิกิริยาร่วม RhCrOx มาทดสอบประสิทธิภาพการผลิตแก๊สไฮโดรเจนภายใต้การฉายแสงที่ตามองเห็น ในสภาวะที่มีสารเอื้อให้เกิดปฏิกิริยา TEOA พบว่า ตัวอย่าง Al-SrTiO3/g-C3N4 …

Go to article

Modification Of Natural Fibrous Materials For Sar-Cov-2 Diagnostic And Ph-Simulated Theranostic Applications, Pornchanok Punnoy Jan 2023

Modification Of Natural Fibrous Materials For Sar-Cov-2 Diagnostic And Ph-Simulated Theranostic Applications, Pornchanok Punnoy

Chulalongkorn University Theses and Dissertations (Chula ETD)

This dissertation investigates the development of colorimetric sensors utilizing natural fibrous materials modified by nanomaterials to enhance the performance of chemical sensors and theranostic devices for healthcare applications. The work is divided into two main sections. The first section, cellulose is utilized as a dual-function platform for qualitative screening of SAR-CoV-2 for COVID-19 diagnosis by colorimetric sensor and quantitative detection by mass spectrometry. The cellulose is modified with gold nanoparticles conjugated to monoclonal antibodies, enabling the specific detection of viral protein antigens through colorimetric changes resulting from nanoparticle aggregation. This platform demonstrates a detection range from 0.01 to 1 µg·mL−1 …

Go to article

Silver Doped Nanoceria (Agcnp) Integrated Silk Scaffold For Chronic Wound Healing, Architha K. Venkatesan Jan 2023

Silver Doped Nanoceria (Agcnp) Integrated Silk Scaffold For Chronic Wound Healing, Architha K. Venkatesan

Honors Undergraduate Theses

Chronic wound healing can be seriously impeded by the formation of biofilms, infections, peri-wound edema, hematoma, osteomyelitis, and the formation of reactive oxidative species (ROS). We hypothesize that a scaffold created from Silver-Doped Nanoceria (AgCNP) embedding silk can be beneficial to aid the wound healing process, inhibit inflammation and prevent microorganisms from forming a biofilm over the wound. Current wound healing methods such as intradermal injections are not advantageous to use since they can cause unwanted responses elsewhere in the body other than the wound site. Silk, however, has a positive impact on the wound healing effect and can be …

Go to article

Thermal And Electrical Properties Of Spark Plasma Sintered (Ti,Cr)B2 Ceramics, Steven M. Smith, Lun Feng, William Fahrenholtz, Gregory E. Hilmas, Laura Silvestroni Jan 2023

Thermal And Electrical Properties Of Spark Plasma Sintered (Ti,Cr)B2 Ceramics, Steven M. Smith, Lun Feng, William Fahrenholtz, Gregory E. Hilmas, Laura Silvestroni

Mathematics and Statistics Faculty Research & Creative Works

Thermal and electrical properties were measured for TiB2 ceramics containing varying CrB2 contents up to 33 mol%. The room-temperature thermal diffusivity decreased with increasing Cr content from 0.330 ± 0.003 cm2/s for pure TiB2 to 0.060 ± 0.003 cm2/s for (Ti0.66Cr0.33)B2. The amount of anisotropy in the coefficients of thermal expansion increased with increasing Cr content and the c-axis had the greatest dependence on Cr addition, with an increase of more than 25% in the thermal expansion for 33 mol% CrB2 compared to TiB2, whereas the a-axis only increased by about 8%. The electrical conductivity was the lowest for (Ti0.66Cr0.33)B2 …

Go to article

Cascaded Sapphire Fiber Bragg Gratings Inscribed By Femtosecond Laser For Molten Steel Studies, Dinesh Reddy Alla, Deva Prasad Neelakandan, Farhan Mumtaz, Rex E. Gerald, Laura Bartlett, Ronald J. O'Malley, Jeffrey D. Smith, Jie Huang Jan 2023

Cascaded Sapphire Fiber Bragg Gratings Inscribed By Femtosecond Laser For Molten Steel Studies, Dinesh Reddy Alla, Deva Prasad Neelakandan, Farhan Mumtaz, Rex E. Gerald, Laura Bartlett, Ronald J. O'Malley, Jeffrey D. Smith, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

This research reports a distributed fiber optic high-temperature sensing system tailored for applications in the steel industry and various other sectors. Recent advancements in optical sensor technology have led to the exploration of sapphire crystal fibers as a solution for sensing in harsh environments. Utilizing a femtosecond (fs) laser, cascaded fiber Bragg gratings (FBGs) were meticulously fabricated within a multimode sapphire optical fiber. These FBGs endowed the system with distributed sensing capabilities and underwent rigorous testing under extreme temperatures, reaching up to 1,800 °C. The study delves into the investigation of the FBG reflection spectrum, facilitated by the development of …

Go to article

Predicting Compressive Strength And Hydration Products Of Calcium Aluminate Cement Using Data-Driven Approach, Sai Akshay Ponduru, Taihao Han, Jie Huang, Aditya Kumar Jan 2023

Predicting Compressive Strength And Hydration Products Of Calcium Aluminate Cement Using Data-Driven Approach, Sai Akshay Ponduru, Taihao Han, Jie Huang, Aditya Kumar

Electrical and Computer Engineering Faculty Research & Creative Works

Calcium aluminate cement (CAC) has been explored as a sustainable alternative to Portland cement, the most widely used type of cement. However, the hydration reaction and mechanical properties of CAC can be influenced by various factors such as water content, Li2CO3 content, and age. Due to the complex interactions between the precursors in CAC, traditional analytical models have struggled to predict CAC binders' compressive strength and porosity accurately. To overcome this limitation, this study utilizes machine learning (ML) to predict the properties of CAC. The study begins by using thermodynamic simulations to determine the phase assemblages of …

Go to article

Drop Wetting And Sliding On Soft, Swollen Elastomers, Zhuoyun Cai Jan 2023

Drop Wetting And Sliding On Soft, Swollen Elastomers, Zhuoyun Cai

Theses and Dissertations--Chemical and Materials Engineering

Soft, slippery surfaces have gained increasing attention due to their wide range of potential applications, for example in self-cleaning, anti-fouling, liquid collection, and more. One design approach in creating slippery surfaces is using a swollen elastomer, which is a polymer network swollen with a lubricant. This type of surface may be beneficial for longer-term use than standard lubricant-infused surfaces, and provides a versatile surface with tunable mechanical properties. Hence, understanding the physics of soft surface interactions is important for fundamental soft matter physics, biomaterials, adhesives, and coatings. This research experimentally investigates wetting on soft infused networks, with the aim of …

Go to article

Effects Of Confinement On Ionic Liquids And Deep Eutectic Solvents For The Design Of Catalytic Systems, Electrochemical Devices, And Separations, Andrew Drake Jan 2023

Effects Of Confinement On Ionic Liquids And Deep Eutectic Solvents For The Design Of Catalytic Systems, Electrochemical Devices, And Separations, Andrew Drake

Theses and Dissertations--Chemical and Materials Engineering

Confinement of ionic liquids (ILs) and deep eutectic solvents (DESs) within mesoporous materials such as silica helps to control the local environment within the pores for applications such as catalysis, electrochemistry, and absorption. Silica thin films with 2.5 and 8 nm pores and micron-sized silica particles with pore diameters of 5.4 and 9 nm were synthesized to study the effect of nanoconfinement on ILs 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]), and DESs reline and ethaline (choline chloride and urea or ethylene glycol). Silica thin films with vertically aligned, well ordered, and accessible pores were synthesized via the evaporation-induced …

Go to article

Development Of Interatomic Potential Of High Entropy Diborides With Artificial Intelligence Approach To Simulate The Thermo-Mechanical Properties, Nur Aziz Octoviawan Jan 2023

Development Of Interatomic Potential Of High Entropy Diborides With Artificial Intelligence Approach To Simulate The Thermo-Mechanical Properties, Nur Aziz Octoviawan

Graduate Theses/Dissertations

The interatomic potentials designed for binary/high entropy diborides and ultra-high temperature composites (UHTC) have been developed through the implementation of deep neural network (DNN) algorithms. These algorithms employed two different approaches and corresponding codes; 1) strictly local & invariant scalar-based descriptors as implemented in the DEEPMD code and 2) equivariant tensor-based descriptors as included in the ALLEGRO code. The samples for training and validation sets of the forces, energy, and virial data were obtained from the ab-initio molecular dynamics (AIMD) simulations and Density Functional Theory (DFT) calculations, including the simulation data from the ultra-high temperature region (> 2000K). The study …

Go to article

Defect State Study And Surface Patching In Zno Nanoparticles Via Nano- Bio Interaction With Dna Bases, Ummay Honey Jan 2023

Defect State Study And Surface Patching In Zno Nanoparticles Via Nano- Bio Interaction With Dna Bases, Ummay Honey

Graduate Theses/Dissertations

First, this thesis investigates the structural and optical properties of hydrothermally synthesized ZnO nanostructures, focusing on the effects of varying annealing temperatures on their properties. Structural characterizations using micro-Raman spectroscopy, X-ray diffraction (XRD), and morphological study called scanning electronic microscopy (SEM) show changes in crystallinity and intensity with different annealing temperatures. Optoelectronic characterization using photoluminescence spectroscopy reveals changes in luminescence properties near the ultraviolet region with temperature variation and in the visible emission area region. These results provide insights into how annealing temperature can affect the surface layer of ZnO nanostructures and can be applied to improve performance in electronic …

Go to article

First Prev Next Last