Ab Initio Simulations For Oxidation Of An Ultra-High Temperature Ceramic (Hfb2),
2025
Wright State University
Ab Initio Simulations For Oxidation Of An Ultra-High Temperature Ceramic (Hfb2), Wesley I. Black
Browse all Theses and Dissertations
Ultra-High Temperature Ceramics are a class of ceramics that possess high strength and melting points in excess of 3000°C. These ceramics are promising for aerospace applications, where materials need to endure high-temperature and high-stress environments. Utilizing ab initio simulations, this thesis research focuses on the atomistic details of oxidation for a typical ultra-high temperature ceramic material, namely hafnium diboride. The simulations provide energy barriers for transition from the initial to final structures via transition states on the (0 0 0 1) surface. These result in estimates for reaction rates and other thermodynamic features that are essential for assessing applicability under …
Design And Development Of A Rapid Tensile Quench Rig,
2025
The University of Akron
Design And Development Of A Rapid Tensile Quench Rig, Tyler Jewell, Justin Naylor
Williams Honors College, Honors Research Projects
This report outlines the design process and implantation of a tensile quenching rig that incorporated forced convection and a frequency generator. When any metal is quenched, a vapor barrier forms around it. When this happens, it limits the heat flux that may occur until the barrier turns into just nucleate boiling. The vapor barrier acts as an insulator and causes the heat flux to fluctuate, causing uneven hardening which would limit the use of some materials. To combat this effect, we are trying to use forced convection, and something new, which is adding high frequency waves into the quenching process. …
Study Of Fiber-Loaded Slurries For Ceramic Matrix Composite Fabrication By Additive Manufacturing,
2025
Wright State University
Study Of Fiber-Loaded Slurries For Ceramic Matrix Composite Fabrication By Additive Manufacturing, Gaspard Matondo
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We studied the additive manufacturing of an alumina-matrix composite reinforced with alumina fibers using the Admatec Admaflex 3D printer, which utilizes digital light processing technology. Oxide-oxide composites are composite materials in which both the matrix and the reinforcing element are ceramic oxides. Monolithic alumina ceramic exhibits a good combination of thermal and mechanical properties, including thermal shock resistance, high melting point, thermal oxidation resistance, good thermal conductivity, hardness, and mechanical strength. However, it is very brittle. Introducing alumina fiber as a reinforcing material into the alumina matrix is expected to enhance mechanical properties, particularly toughness, making the ceramic matrix composite …
Enhancing Acetone Gas Sensor Performance With Cobalt Oxide Doping In Lafeo3 Prepared By Co-Precipitation,
2025
Chulalongkorn University
Enhancing Acetone Gas Sensor Performance With Cobalt Oxide Doping In Lafeo3 Prepared By Co-Precipitation, Andhy Setiawan, Farah Aprisza Sheelmarevaa, Muhamad Taufik Ulhakim, Dani Gustaman Syarif, Endi Suhendi
Journal of Metals, Materials and Minerals
Semiconductor-based gas sensors frequently encounter difficulties in attaining optimal performance due to challenges such as temporal stability and low sensitivity, stemming from their insulating properties at room temperature. To address these limitations, this study proposes a novel approach by preparing cobalt-doped LaFeO3 (LaFeO3-Co) using the co-precipitation method, with doping concentrations of 2.5 mol% and 5.0 mol%. The acetone gas sensors were fabricated into thick films via the screen-printing technique, and their performance was thoroughly characterized. X-ray diffraction (XRD) analysis confirmed a cubic crystal structure, and the addition of 2.5 mol% cobalt was found to reduce the particle size of LaFeO3, …
Enhanced Photocatalytic Reduction Of Cr(Vi) Under Visible Light A Magnetically Separable Tio2-Fe/Fe3o4 Photocatalyst Prepared From Iron Rusty Waste,
2025
Chulalongkorn University
Enhanced Photocatalytic Reduction Of Cr(Vi) Under Visible Light A Magnetically Separable Tio2-Fe/Fe3o4 Photocatalyst Prepared From Iron Rusty Waste, Khoirunisa Khoirunisa, Novianti Dwi Lestari, Endang Tri Wahyuni, Taufik Abdillah Natsir
Journal of Metals, Materials and Minerals
This research deals with enhancing the visible activity and generating the magnetic property of TiO2 by Fe doping and Fe3O4 impregnation respectively, using rusty iron waste as Fe source. The prepared TiO2-Fe/Fe3O4 photocatalysts were characterized by SR-UV/Visible, FTIR, XRD, and SEM-EDX instruments. The resulting photocatalysts are responsive to visible light and can be separated magnetically and used for photoreduction of Cr (VI) ions. In the photoreduction of Cr(VI) over TiO2-Fe/Fe3O4 photo-catalysts with various amounts of Fe dopant and alteration of Fe3O4 fraction, the photocatalyst mass, irradiation time, and solution pH were optimized. The research results assign that doping Fe to …
Hydroxyl Combined With Nitrogen On Biomass Carbon Promotes The Electrocatalytic H2o2 Selectivity,
2025
Chulalongkorn University
Hydroxyl Combined With Nitrogen On Biomass Carbon Promotes The Electrocatalytic H2o2 Selectivity, Jiabi Jiang, Danni Deng, Yuchao Wang, Yingbi Chen, Yu Bai, Meng Wang, Xiang Xiong, Yongpeng Lei
Journal of Metals, Materials and Minerals
Elevating the selectivity of two-electron oxygen reduction reaction (2e‒ ORR) is challenging. Herein, the hydroxyl combined with nitrogen on biomass carbon exhibits a high H2O2 selectivity over a wide potential range of 0 V to 0.5 V vs. RHE, which is nearly 97% at 0.3 V vs. RHE. The combination of hydroxyl and nitrogen improves the adsorption and desorption of intermediates, finally changing the reaction pathway and promoting the selectivity of 2e‒ ORR. The Faradaic efficiency (FE) reaches 98% at 0.3 V vs. RHE. Furthermore, the typical organic pollutants were degraded on site in flow cell. This work illustrates the …
Elucidating The Corrosion Of Carbon Steel In Hybrid Monoethanolamine Solutions Containing Methanol Or N-Methyl-2-Pyrrolidone,
2025
Chulalongkorn University
Elucidating The Corrosion Of Carbon Steel In Hybrid Monoethanolamine Solutions Containing Methanol Or N-Methyl-2-Pyrrolidone, Pui Yee Tan, Lian See Tan, Swee Pin Yeap, Peck Loo Kiew, Mee Kee Wong, Azmi Mohd Shariff
Journal of Metals, Materials and Minerals
Corrosion has been a persistent issue in carbon dioxide (CO2) absorption unit that needs to be resolved in order to prolong the life span of the absorber unit. In this regard, understanding the corrosion behaviour, particularly in hybrid monoethanolamine (MEA) solutions, is crucial. This study aims to give detail information on the role of different process parameters, encompassing types of amine solution, temperature, and CO2 loading on the corrosion behaviour of carbon steel in system containing hybrid solution of monoethanolamine (MEA) and methanol (MeOH) or N-methyl-2-pyrrolidone (NMP). Here, the corrosion extent of the carbon steel was evaluated using gravimetric experiments. …
High-Binding Affinity Nanobody Against Sars-Cov-2 Xbb.1.5: Computational-Based Protein Engineering,
2025
Chulalongkorn University
High-Binding Affinity Nanobody Against Sars-Cov-2 Xbb.1.5: Computational-Based Protein Engineering, Phoomintara Longsompurana, Napat Kongtaworn, Rungtiva P. Poo-Arporn, Thanyada Rungrotmongkol
Journal of Metals, Materials and Minerals
The emergence of the SARS-CoV-2 variant XBB.1.5 has triggered a global health crisis by enhancing viral entry into cells via its spike protein. This study addresses the urgent need to develop neutralizing nanobodies (Nbs) to counteract the SARS-CoV-2 virus. Our aim was to identify a lead Nb and enhance its binding affinity to the receptor-binding motif (RBM) on the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein (S-protein) using computational methods. A total of 29 Nbs were screened against the XBB.1.5 RBD using the HDOCK server to select a lead Nb. This investigation revealed that Nb_7KGK exhibited the highest binding …
Electrochemical Study Of Zn-Fe Alloy Coatings On Mild Steel For Automotive Applications,
2025
Chulalongkorn University
Electrochemical Study Of Zn-Fe Alloy Coatings On Mild Steel For Automotive Applications, Ramesh Bhat, A. Chitharanjan Hegde
Journal of Metals, Materials and Minerals
This study investigates the electrochemical behavior of Zn-Fe alloy deposited on mild steel (MS) substrates for automotive applications. The electrodeposition of a Zn-Fe alloy onto MS using an acid chloride bath, with 1,2,4-Triazole as an additive to enhance the uniformity of the deposit. The hull cell method was used to optimize the bath composition and operating conditions. The coatings were produced using electrodeposition at varying current densities, with 3 A∙dm‒2 identified as the optimal current density (CD) for achieving uniform coatings. The microstructural properties, including crystallite size and micro-strain, were analyzed using X-ray diffraction (XRD) and Williamson-Hall (W-H) analysis, revealing …
Influence Of The Casting Processes And Aging Times On The Microstructure And Hardness Of Alsi12 Cu Cast Alloys,
2025
Chulalongkorn University
Influence Of The Casting Processes And Aging Times On The Microstructure And Hardness Of Alsi12 Cu Cast Alloys, Said Beroual, Pascal Paillard, Yann Borjon-Piron
Journal of Metals, Materials and Minerals
The present study investigated the effects of the casting processes and aging times on the micro-structure and hardness of commercial AlSi12Cu alloys. The primary goal was to assess how various aging times affect the maximum hardness of the alloy and to evaluate the influence of cooling rates on hardness values obtained from sand casting (SC) and High-pressure die casting (HPDC). For both casting alloys, the solution heat treatment was performed at 540℃, followed by quenching. The alloys were then aged at 180℃ for various durations, ranging from 10 min to 50 h. The results reveal significant microstructural changes in the …
Photodegradation Of Malachite Green Using 2d G-C3n5 Nanosheet: A Promising Metal Free Catalyst,
2025
Chulalongkorn University
Photodegradation Of Malachite Green Using 2d G-C3n5 Nanosheet: A Promising Metal Free Catalyst, Sonali Biswal, Swayam Aryam Behera, Asima Subhadarshini, P. Ganga Raju Achary, Binita Nanda
Journal of Metals, Materials and Minerals
Environmental issues have become more serious these days due to the growth of modern industries. The paper and textile industries, in particular, were heavily dependent on the printing and discharge of dye, which constantly leaked into the water ecology and constituted a serious risk to public health. Organic wastewater treatment and remediation for its associated risks have received a lot of attention lately. This work explored the potential of the g-C3N5 nanostructure as a novel photocatalyst for malachite green degradation in aqueous solution while exposed to visible light. The nanocomposite was fabricated through an ultrasonicate-assisted technique. A number of analysis …
Regulating Copx/Co Heterostructures For Enhanced Electrocatalytic Activity Toward Hydrazine Oxidation Reaction,
2025
Chulalongkorn University
Regulating Copx/Co Heterostructures For Enhanced Electrocatalytic Activity Toward Hydrazine Oxidation Reaction, Qinquan Lin, Rui Zhang, Changli Yan, Qizhao Hu, Shangbin Sang, Qiumei Wu, Kaiyu Liu, Hongtao Liu
Journal of Metals, Materials and Minerals
Hydrazine hydrate (N2H4∙H2O) is considered an ideal fuel for fuel cells. Constructing a cobalt phosphide/cobalt (CoPx/Co) heterostructure can achieve efficient electrocatalytic activity for hydrazine oxidation reaction. Traditional strategies for constructing CoPx/Co heterostructures took less consideration on the exposure of the active sites. In this study, 3D nanoflower-like nano CoPx/Co heterostructures with highly exposed active sites were obtained on a nickel foam (NF) through a dual-component phosphating strategy, i.e., regulating the relative content of Co and Co(OH)2 with cathodic current density and utilizing the differences in their phosphating behaviors. The potential at 100 mA∙cm‒2 and Tafel slope of the optimized CoPx/Co(375)@NF …
Facile Synthesis Of Bamno3-Zro2 Composite: A Step Towards The Photocatalytic Degradation Of Organic Dye,
2025
Chulalongkorn University
Facile Synthesis Of Bamno3-Zro2 Composite: A Step Towards The Photocatalytic Degradation Of Organic Dye, Kirttimayee Mohanta, Swayam Aryam Behera, Binita Nanda, P. Ganga Raju Achary
Journal of Metals, Materials and Minerals
Environmental contamination by synthetic dyes, particularly Methylene Blue (MB), presents a significant threat to aquatic ecosystems and human health due to their chemical stability and toxicity. This study investigates the photocatalytic degradation of MB using a BaMnO3:ZrO2 composite synthesized in a 1:2 ratio via a straightforward wet-chemical method. Structural and optical characterizations were performed using X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and Ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS). The composite exhibited a reduced bandgap of 2.88 eV and uniform nanoscale morphology, both favorable for visible-light-driven photocatalysis. Under visible-light irradiation, the catalyst achieved 89% degradation efficiency within …
The Effects Of Graphene Nanoplatelets And Microcrystalline Cellulose On The Mechanical Properties Of Fiberglass And Carbon Fiber Composites,
2025
Chulalongkorn University
The Effects Of Graphene Nanoplatelets And Microcrystalline Cellulose On The Mechanical Properties Of Fiberglass And Carbon Fiber Composites, Duangjai Srisamut, Nathawat Poopakdee, Warut Thammawichai
Journal of Metals, Materials and Minerals
This study investigated how graphene nanoplatelets (GNP) and microcrystalline cellulose (MCC) affect the mechanical properties of epoxy (EP), carbon fiber (CF), and fiberglass (FG) composites. The tensile and flexural properties of GNP-EP and MCC-EP of varying reinforcement concentrations were examined. Results indicated significant improvements on tensile and flexural properties by GNP and MCC. At 0.1 wt% GNP, tensile and flexural strengths increased by 10% and 21%, while 2.0 wt% improved flexural modulus by 65%. Similarly, 2.0 wt% MCC improved tensile strength, modulus, and flexural modulus by 11%, 11%, and 46%, respectively, and a 26% increase in flexural strength at 1.0 …
Synthesis Temperature-Driven Enhancements In Bioi Photocatalysis: A Hydrothermal Approach,
2025
Chulalongkorn University
Synthesis Temperature-Driven Enhancements In Bioi Photocatalysis: A Hydrothermal Approach, Sorawit Thueanbangyang, Kittiyaporn Singsumphan, Varunya Atimayulerd, Chutima Nakmuk, Cheewita Suwanchawalit, Montri Aiempanakit
Journal of Metals, Materials and Minerals
Bismuth oxyiodide (BiOI) is a promising photocatalyst for visible-light-driven environmental remediation. However, its photocatalytic efficiency is highly dependent on synthesis conditions, particularly hydrothermal temperature, which governs its structural, optical, and electronic properties. In this study, BiOI was synthesized via a hydrothermal method at temperatures of 120℃, 150℃, 180℃, and 210℃ to investigate the effect of temperature on its photocatalytic performance systematically. Comprehensive characterizations, including X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, UV-vis diffuse reflectance spectroscopy, photoluminescence and photocatalytic degradation studies, were conducted to analyze crystallinity, morphology, band structure and charge transfer properties. The results …
Bagasse Lignin For Single-Used Food Packaging Applications: Uv-Barrier, Antioxidant, Migration And Cytotoxicity,
2025
Chulalongkorn University
Bagasse Lignin For Single-Used Food Packaging Applications: Uv-Barrier, Antioxidant, Migration And Cytotoxicity, Pawarisa Wijaranakul, Bongkot Hararak, Wanwitoo Wanmoolee, Prapudsorn Wannid, Weerawan Laosiripojana
Journal of Metals, Materials and Minerals
This study examined PLA biocomposite films made from organosolv lignin extracted from Thai agro-waste, specifically sugarcane bagasse (BG), to assess their suitability for food packaging, focusing on their physical, thermal, optical, UV-shielding, antioxidant, and migration properties. Extracted BG-lignin exhibited free radical scavenging ability with an EC50 value of 400 µg/ml, reducing DPPH absorbance by 50%. PLA composite films with BG-lignin dosage from 0.1 to 1.0 wt.% were successfully fabricated via conventional blown film extrusion. Addition of BG-lignin at 0.5 wt.% and 1.0 wt.% to PLA films decreased UV transmittance from 90% to 30% and 12%, respectively, without compromising optical clarity. …
Coating Of Zinc Substrates With Fluorosilane Molecules Using A Water-Treatment Technique As A Pre-Coating Procedure For The Creation Of Superhydrophobic Surfaces,
2025
Chulalongkorn University
Coating Of Zinc Substrates With Fluorosilane Molecules Using A Water-Treatment Technique As A Pre-Coating Procedure For The Creation Of Superhydrophobic Surfaces, Renz Ronald R. Prieto, Marvin U. Herrera
Journal of Metals, Materials and Minerals
Superhydrophobic surfaces were successfully created when zinc substrates were coated with molecules with low surface energy through grafting of fluorosilane molecules. The zinc substrate underwent water-treatment technique as a pre-coating procedure to enhance the reaction sites for the grafting of fluorosilane molecules. The water contact angle of the samples went as high as 161.1° ± 0.8°. At lower fluorosilane-ethanol soaking times, water contact angles have lower values while at higher soaking time, it has higher water contact angle values. At 240 min fluorosilane-ethanol soaking time, optimum value of water contact angle was achieved. Fluorosilane molecules are widely distributed through the …
Sulfur-Doped Carbon Dots Derived From Caffeine: A Highly Efficient Photocatalyst For Organic Dye Degradation,
2025
Chulalongkorn University
Sulfur-Doped Carbon Dots Derived From Caffeine: A Highly Efficient Photocatalyst For Organic Dye Degradation, Ganyaporn Wongwaen, Koranut Dechsri, Praneet Opanasopit, Montri Aiempanakit, Cheewita Suwanchawalit
Journal of Metals, Materials and Minerals
Sulfur-doped carbon dots (S-doped CDs) were synthesized via a solvothermal method using caffeine as a carbon precursor and sodium sulfide as a sulfur source. Characterization using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet -visible (UV-Vis) spectroscopy, and photoluminescence spectroscopy (PL) confirmed successful sulfur incorporation. TEM revealed a uniform size distribution and graphitic structures, while UV-Vis analysis showed a reduction in the bandgap from 3.29 eV to 3.10 eV, improving light absorption and charge carrier separation. The photocatalytic activity of S-doped CDs was evaluated for indigo carmine (IC) dye degradation under UV irradiation, where 2S-CDs …
Impacts Of Calcination Temperature On The Crystallography, Granulometry And Impedance Of Licomno4,
2025
Chulalongkorn University
Impacts Of Calcination Temperature On The Crystallography, Granulometry And Impedance Of Licomno4, Chee Wayne Tan, Zul Hilmi Che Daud, Zainab Asus, Mohd Hasbullah Idris, Izhari Izmi Mazali, Mohd Kameil Abdul Hamid
Journal of Metals, Materials and Minerals
Spinel structured lithium cobalt manganese oxide (LiCoMnO4) which exhibit reduction potential surpassing 5.0 V (vs. Li0 | Li+) was identified to be one of the prospective cathode candidates for next generation lithium-ion electrochemical systems. This article highlights the significance of calcination temperature on the crystallography of the resultant electroceramic compound as well as the corresponding response on the granulometry and impedance of LiCoMnO4. LiCoMnO4 compounds synthesised via sol-gel reaction in the first instance were converted into xerogel and subsequently subjected to facile one-step calcination protocol. Crystallography of the post-calcinated compounds were characterised via powder x-ray diffraction (XRD) technique. Temperature ranging …
Effect Of Lanthanum Doping On Phase Transition, Piezoelectric And Energy Storage Properties Of Lead-Free 0.93(Bi0.5na0.5)Tio3‒0.07batio3 Ceramics,
2025
Chulalongkorn University
Effect Of Lanthanum Doping On Phase Transition, Piezoelectric And Energy Storage Properties Of Lead-Free 0.93(Bi0.5na0.5)Tio3‒0.07batio3 Ceramics, Pathit Premwichit, Songphop Jaila, Sasiporn Prasertpalichat
Journal of Metals, Materials and Minerals
In this study, lead-free (Bi0.465Na0.465Ba0.07)(1–x)LaxTiO3 (x=0.0‒0.04) ceramics were synthesized using a conventional solid-state reaction method. All samples showed a single-phase perovskite structure with pseudocubic symmetry. The dense microstructure revealed a decrease in average grain size as x increased. La3+ addition stabilized polar nanoregions (PNRs), shifting the ferroelectric to relaxor phase transition temperature (TF₋R=104℃ for x=0.0) to below room temperatures as La3+ content increased. This resulted in a transition from a rectangular to a relaxor-like thin P–E loop (x≥0.01), indicating a shift from ferro-electric (FE) to relaxor ferroelectric (RFE), which …
