Digital Commons Network^™

The Middle School Transition: Exploring Student Perceptions On The Transition From Elementary To Middle School, Cody T. Weed

Education Dissertations

The purpose of this study was to understand middle school students’ perceptions of their transition from elementary school to better learn the interactions and dynamics that unfold between them and their immediate environment. The middle school transition is a pivotal developmental phase marked by significant logistical, academic, and social–emotional challenges. Grounded in transition theory, the 4S framework, and stage-environment fit theory, this research explores the interactions between students and their new environment. Utilizing an embedded design mixed-methods approach, this study surveyed sixth-grade students at a public middle school in Eastern Washington. The goal was to illuminate students’ needs and concerns …

Pat Conroy First Edition Book Collection - Accession 1747, Donald Patrick Conroy

Manuscript Collection

The Pat Conroy First Edition Book Collection consists of first edition publications authored by Donald Patrick “Pat” Conroy (1945–2016), an acclaimed American novelist whose work is closely associated with the cultural, social, and physical landscapes of the South Carolina Lowcountry. Many of the volumes in this collection are signed by the author, enhancing their research and evidentiary value.

The collection spans Conroy’s literary career from his debut memoir The Boo (1970) through The Death of Santini (2013), a reflective work that revisits characters and themes central to his earlier writings. Included are major novels, memoirs, and nonfiction works such as …

Pxaa: A Root-Cause Decision-Support System For Airline Passenger Complaints Using Sentiment Analysis And Complaint Classification, Adélia Acacio Da Silva, Stefani Rabelo De Campos Nunes

ICT

PXAA (Passenger Experience Analytics Assistant) is a machine learning and decision-support prototype developed to analyse airline passenger complaints using sentiment analysis and complaint classification techniques. The project follows the CRISP-DM methodology and uses airline passenger reviews collected from AirlineQuality.com through Python web scraping. Natural language processing (NLP) techniques were applied to clean and preprocess the textual data, while logistic Regression was used to classify passenger sentiment into positive, negative and neutral categories.

The project also implemented rule-based complaint classification to identify common complaint themes such as delays, baggage issues, customer service problems, comfort issues, payments/refund complaints and communication failures. These …

Design And Evaluation Of A Supervised Machine Learning-Based Intrusion Detection System., Tarquin Qazi

ICT

This project involves designing and evaluating a supervised machine-learning-based intrusion detection system (IDS) using the CIC-IDS2017 dataset. The project is structured around the cross-industry standard process for data mining (CRISP-DM) framework. The dataset comprises over 2.8 million labelled instances and was cleaned and reduced from 78 to 63 features via redundancy analysis. These data were used to train and tune three supervised classifiers: Logistic Regression algorithm as a linear baseline, a Decision Tree algorithm and a Random Forest algorithm. Hyperparameter optimisation was conducted using RandomizedSearchCV with 3-fold cross-validation, optimising for the F1-macro scoring metric.

While the random forest performed similarly …

Comparative Economic Impact Modelling Of Floods Vs Drought On A Global Scale, Diogo Lemos Aguiar, Paulo Henrique Oliveira Machado

ICT

Climate change is generating unprecedented economic losses through extreme weather events, yet comparative predictive analysis between different hazard types remains limited. This report presents a Machine Learning–Based Comparative Economic Impact Modelling System designed to predict and compare the economic damages caused by floods and droughts on a global scale. The system integrates historical disaster records from the EM-DAT International Disaster Database with country-level socioeconomic indicators from the World Bank's World Development Indicators, applying supervised regression modelling to a unified dataset of 1,301 disaster events across 133 countries from 2000 to 2025. XGBoost and a Multi-Layer Perceptron Neural Network were evaluated …

Predicting Co₂ Emissions From Cattle-Driven Deforestation In The Amazon Rainforest Using Machine Learning, Daniel Ambrosio, Suelen Rocha

ICT

Deforestation has become a major environmental issue worldwide, especially in the Amazon Rainforest, which is known as one of the world’s largest carbon sinks. This region has been significantly impacted by cattle farming, contributing to increased CO₂ emissions and land degradation. As Brazil is one of the world’s largest beef producers and exporters, the environmental impact of livestock production has attracted increasing attention from organisations, governments, and sustainability analysts.

This project aims to analyse the relationship between cattle farming, deforestation, and CO₂ emissions in the Amazon using Machine Learning. Using the CRISP-DM framework, the project explored each stage of the …

A Review On Biomass-Derived Hard Carbon Anodes For Sodium-Ion Batteries : From Carbon Precursors To Storage Mechanisms, Anqi Lu, Jiaqian Qin

Journal of Metals, Materials and Minerals

The rapid development of sustainable energy technologies has intensified the demand for cost-effective and high-performance energy storage systems. Sodium-ion batteries (SIBs) are regarded as one of the most promising alternatives to lithium-ion batteries (LIBs) owing to their low cost, abundant sodium resources, and similar electrochemical mechanisms to LIBs. Hard carbon (HC) has attracted significant attention as the predominant anode material for SIBs due to its low cost, structural tunability, and availability from diverse precursors. Nevertheless, challenges remain, including the unclear Na+ storage mechanism, limited rate capability, and strong dependence on precursor type. This review systematically summarizes recent advances in HC …

Mechanical Properties And Crystallization Of Polybutylene Terephthalate Reinforced With Glass Flakes And Aluminum Powder, Nattakarn Hongsriphan, Pajaera Patanathabutr

Journal of Metals, Materials and Minerals

This research investigated mechanical properties and crystallization of poly(butylene terephthalate) composites by adding glass flakes (GF) and aluminum particles (Al). The concentration of the GF was 3 wt% or 5 wt%, and the Al was 0.5 wt% or 1.0 wt%. The stress-strain curves of the PBT-based composites showed yielding and necking. The PBT/GF/Al composites with GF/Al ratios of 3/0.5 wt/wt%, 3/1.0 wt/wt%, 5/0.5 wt/wt%, and 5/1.0 wt/wt% had Young’s moduli of 11.44%, 11.70%, 16.81%, and 19.31% higher than that of neat PBT, respectively. In the presence of Al at 1.0 wt%, the flexural modulus of the PBT/GF/Al composites increased to …

Synthesis, Structure, And Electrochemical Properties Of The Ni(Oh)2/Nimoo4 Composite On The Rgo/Nf Template For Hybrid Battery-Supercapacitor Electrodes, Retno Asih, Haniffudin Nurdiansah, Rogabe Sianipar, Ida Ayu Gayatri, Lukman Noerochim, Diah Susanti, Isao Watanabe, Darminto Darminto

Journal of Metals, Materials and Minerals

The growing demand for renewable and sustainable energy has intensified research on advanced energy-storage systems that can deliver both high energy and power densities. In this study, a Ni(OH)2/ NiMoO4 composite on a reduced graphene oxide/nickel foam (rGO/NF) template was synthesized through a hydrothermal and electrodeposition route to construct a hybrid battery-supercapacitor electrode. The unique hierarchical design combines the pseudocapacitive activity of Ni(OH)2/NiMoO4 with the excellent conductivity of rGO and the high surface area of NF, enabling efficient electron and ion transport. Structural and morphological analyses confirm the successful formation of the Ni(OH)2/NiMoO4/rGO/NF architecture. The electrode exhibits a specific capacitance …

Effect Of Cu Content On Microstructure, Morphology, And Antibacterial Properties Of Ti-Cu Alloy Thin Films, Chittra Kedkaew, Phalakorn Khwansungnoen, Tanattha Rattana

Journal of Metals, Materials and Minerals

Ti-Cu alloy thin films exhibit considerable potential for the development of advanced antibacterial surfaces, particularly for biomedical applications. In this research, Ti-Cu binary alloy thin films with a wide range of Cu content from 25.8 at% to 77.8 at% were deposited using magnetron co-sputtering with pure Ti and Cu as the targets. The composition of Cu in the films can be controlled by the applied power of Cu targets. This study investigated the effect of Cu content on the microstructural, morphological, and antibacterial properties using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Atomic force microscopy (AFM), X-ray photoelectron …

Contributions Of Carbon Content And Cooling Rate On Phase Transformations And Mechanical Properties Of Sintered Fe-1.5cr-0.2mo-Xc Alloys, Mantana Yaruan, Wantana Koetniyom, Thanyaporn Yotkaew, Nattaya Tosangthum, Ruangdaj Tongsri

Journal of Metals, Materials and Minerals

Microstructural development in sintered Fe-1.5Cr-0.2Mo-xC alloys, produced under different cooling rates of 0.1℃∙s‒1 and 5.4℃∙s‒1, was investigated. It was found that, in slowly sintered Fe-1.5Cr-0.2Mo-xC alloys, the microstructure changed from hypoeutectoid to eutectoid and to hypereutectoid steel microstructural features with increasing carbon content. Under the fast-cooling rate of 5.4℃∙s‒1, the microstructural change with respect to the increase of carbon content involved the competition between the formation of ferrite + carbide mixture and that of martensite-austenite constituent. The increase of tensile strength of slowly cooled sintered Fe-1.5Cr-0.2Mo-xC alloys with increasing carbon content was attributed to …

Effect Of Garnet Incorporation On The Functional Properties Of Sunscreens, Parinya Chakartnarodom, Kanyarat Munmani, Sureerat Polsilapa, Duangrudee Chaysuwan, Wichit Prakaypan, Passakorn Sonprasarn, Edward Laitila, Nuntaporn Kongkajun

Journal of Metals, Materials and Minerals

Garnet, a silicate mineral, was investigated as a replacement for the TiO2-based compound in sunscreen formulations. Samples containing garnet were evaluated for color shade, viscosity, sun protection factor (SPF), and water resistance. Substituting the TiO2-based compound with garnet reduced both viscosity and SPF but markedly enhanced water resistance. This improvement is attributed to the physical reinforcement provided by garnet particles, which strengthen the sunscreen film and reduce wash-off under water exposure. Garnet incorporation also altered the product’s appearance from white to a darker brownish-beige tone, improving visual compatibility with a wider range of skin tones.

Effects Of Welding Currents On Microstructure And Corrosion Behaviors Of Inconel 625 Cladding On 2.25cr-1mo Steel By Hot-Wire Tig, Supparat Saeheng, Hein Zaw Oo, Prapas Muangjunburee

Journal of Metals, Materials and Minerals

Hot-wire tungsten inert gas (HW-TIG) cladding has been applied to the steam turbine rotor welding repair. This study investigated the effects of welding currents on microstructure, hardness, and corrosion behavior. The experiments were conducted using four different welding currents applied to bead-on-plate Inconel 625 welds on a 2.25Cr-1Mo steel substrate as the steam turbine rotor material. The selected welding currents were 125 A, 150 A, 175 A, and 200 A. The percentages of weld dilution for different welding currents were also evaluated. Higher welding currents increased weld dilution, weld bead width, and HAZ size. As the welding current increased, the …

Properties And Printability Of Polylactic Acid Films : An Effect Of Polyglutamate Coated Natto As A Bio-Plasticizer, Natrata Thitinardwong, Thira Chavarnakul, Kawee Srikulkit

Journal of Metals, Materials and Minerals

Polylactic acid (PLA) film, a biodegradable alternative to petroleum-based plastics, has gained significant attention for sustainable packaging applications. However, its limited screen-printability remains a barrier to broader commercial use. This study aims to enhance the screen-printability of PLA film by incorporating a polyglutamate coated natto (designated as Nat-M). PLA/Nat-M films having 1%, 3%, and 5% Nat-M were prepared and evaluated for their key performance indicators, including ink adhesion (ASTM D3359), tone reproduction accuracy, and printing resolution. The screen-printing resolution was optimized between 400 DPI and 500 DPI (dots per inch) to achieve optimal tone reproduction and edge sharpness. Additionally, ink …

A Top-Electrode-Based Liquid-Solid Triboelectric Nanogenerator For Energy Harvesting And Ethanol Detection, Subrat Bhol, Nakul Charan Sahu, Sunit Gaurav Mohanty, Vicky Raj Maddala, Basanta Kumar Panigrahi, Premkumar Bhosale

Journal of Metals, Materials and Minerals

Liquid-solid triboelectric nanogenerators (LS-TENGs) offer a promising avenue for self-powered energy harvesting and sensing by exploiting contact electrification at fluid-dielectric interfaces, where droplet dynamics drive charge separation for electrical output without external power. In this work, a top-electrode LS-TENG was fabricated using a polytetrafluoroethylene (PTFE) film on a PMMA substrate with deionised water droplets, achieving an open-circuit voltage of ‒3.4 V, short-circuit current of 3.6 μA, and peak power of 1.48 nW at 100 MΩ under optimised conditions of 2 cm drop height, 45° tilt, and 50 μL volume. Performance scaled with droplet kinetics and volume due to enhanced contact …

Impact Of Chromium Substitution On Structural And Magnetic Properties Of Mnbi-Based Melt-Spun Ribbons, Anh Kha Vuong, Triet Minh Dang, Truong Xuan Nguyen, Duy Anh Vo Nguyen, Hai Van Pham, Nam Hoai Nguyen, Nam Hong Pham, Oanh Kim Thi Vuong, Tan Nhut Nguyen Le, Tuan Van Dinh, Nam Thanh Tran Nguyen, Nhan Thi Tran, Trung Quoc Nguyen, Nhan Thi Tran, Trung Quoc Nguyen, Lu Wei, Vuong Van Nguyen

Journal of Metals, Materials and Minerals

MnBi-based magnetic materials and magnets are of significant interest due to their magnetism without rare earth elements and their ability to replace Nd-Fe-B in high-temperature magnet applications due to its unique feature of enhancing coercivity in the range of 100℃ to 250℃, enabling their energy product (BH)max comparable to NdFeB magnets despite their moderate spontaneous magnetization Msp. To adjust the magnetic properties of MnBi magnets, various elements have been doped to regulate magnetic interactions among the atoms, which subsequently alters Msp and the magneto-crystalline anisotropy energy. In this work, we investigate the effects of chromium doping on the magnetic properties …

Cold Sintering-Assisted Low Temperature Fabrication Of Dense Ba5 Nb4 O15 Ceramics, Usa Sukkha, Apichayaporn Teandam, Phakkhananan Pakawanit, Phitsamai Kamonpha, Wanwilai Vittayakorn, Phieraya Pulphol, Naratip Vittayakorn

Journal of Metals, Materials and Minerals

This study presents a novel approach for fabricating Ba5Nb4O15 (BNO) ceramics at low sintering temperatures via the cold sintering process (CSP), using Ba(OH)2∙8H2O (BOH) as a transient liquid phase. CSP was performed under an external pressure of 10 MPa with a sintering temperature range of 150℃ to 300℃. Optimally, BNO-BOH ceramics achieved a relative density of 93.7 ± 0.43% when sintered at 250℃ for 1 h. Scanning electron microscopy (SEM) suggested that particle densification occurred via a dissolution-precipitation process, which filled pores and formed necks between particles. The study demonstrates that the residual liquid content is crucial for ceramic densification. …

Fabrication Of A Chitosan‒Fe3o4/Activated Carbon/Tio2 Nanocomposite As A Pb(Ii) Heavy Metal Adsorbent, Berliantty Warim Putri, Arif Hidayat, Lya Rizka Herawati, Poppy Puspitasari, Nandang Mufti, Yap Wing Fen, Muhammad Safwan Abdul Aziz, Tahta Amrillah, Ahmad Taufiq

Journal of Metals, Materials and Minerals

Nowadays, water pollution by heavy metal Pb(II) is a significant issue in many countries, including Indonesia. To overcome this problem, a suitable and efficient waste treatment method is necessary. Therefore, in this work, Fe3O4/AC/TiO2 nanocomposite modified with chitosan (CS) for the treatment of Pb (II) waste were investigated. CS was used due to its OH and NH2 functional groups, which enable the formation of a new hybrid nanocomposite that can be used repeatedly. To reduce production costs, environmentally friendly, raw natural materials, such as iron sand, coconut shells, and shrimp shells, were employed. The XRD characterization results indicate that the …

Advanced Hemp-Based Hybrid Composites: A Study On The Influence Of Various Nanofillers On Mechanical And Morphological Properties, Velmurugan Ganesan, Jasgurpreet Singh Chohan, Muthukumar V., Nagaraj M., Lakshmi Narayana S.

Journal of Metals, Materials and Minerals

This study investigates the mechanical and microstructural attributes of epoxy composites with hemp fiber reinforcements and incorporated aluminum oxide (Al2O3), silicon dioxide (SiO2), and magnesium oxide (MgO) nanoparticles at different weight fractions of 0.5 wt%, 1.0 wt%, and 1.5 wt%. Nano-fillers remarkably improved the composite performance, as indicated by tensile and flexural tests conducted by ASTM D3039 and ASTM D790 standards. The composite containing 1.5 wt% Al2O3 outperformed other nano filled composites with a tensile strength of 64 MPa and tensile modulus of 3.6 GPa, versus 52 MPa and 3.0 GPa for the unfilled hemp/epoxy composite. In parallel, flexural strength …

Sintering Behavior And Mechanical Properties Of Ha-Ysz-Ti Composite Sintered By Spark Plasma Sintering, Seyed Mohsen Fatemi, Iman Mobasherpour, Leila Nikzad, Mansour Razavi

Journal of Metals, Materials and Minerals

This research is aimed to determine the best composition of composite fabricated by Spark Plasma Sintering (SPS) to produce a suitable substituent for bone. The applied powder was prepared by the SPS method and comprises hydroxyapatite (HA), yttria-stabilized zirconia (YSZ), and titanium (Ti). Different percentages of components were used to fabricate the composite samples. X-ray diffraction was used to determine the structural phase of the sintered samples while field emission scanning electron microscopy (FE-SEM) was employed for microstructural analysis of the specimens. The behavior of the samples was investigated during sintering. The gas release, displacements, and porosity percentage of the …

Two-Step Sputtering For Depositing Smooth And Thin Zno Films On Non-Heated, Non-Epiready Pet Substrates, Nattaya Tajina Yossapong, Annop Klamchuen, Kittipong Tantisantisom, Ekkaphop Ketsombun, Taworn Intaro, Sakuntam Sanorpim, Warakorn Yanwachirakul

Journal of Metals, Materials and Minerals

Highly crystalline, smooth-surface, and thin zinc oxide (ZnO) films have been successfully deposited on flexible polyethylene terephthalate (PET) substrates using an optimized two-step RF magnetron sputtering technique at ambient temperature. The PET used in this study was a commercially available overhead projector film, which was not epiready-grade and had a lower melting point (~150℃). This issue made high-quality deposition more challenging. In the first step, a thin ZnO buffer layer was deposited at low RF power to provide a smooth and thermally stable surface. This layer served as both a structural template and a thermal barrier during the subsequent high-power …

Sodium Alginate/Aloe Vera/Mangosteen Peel Extraction Hydrogel Composite Films With Anti-Staphylococcal Properties As A Promising Alternative Material In Biomedical Applications, Pruss Chimwai, Poonyarat Apikarnsakulchai, Tirawit Jindaratanaporn, Witsanu Liangaumnuay, Thitima La-Ongthitirat, Purin Somnuake, Pattara Somnuake

Journal of Metals, Materials and Minerals

This study focuses on the development of alternative biodegradable hydrogel films from sodium alginate as a matrix and curing into a hydrogel by CaCl2. Thus, the aloe vera (AV) and the crude extract of mangosteen peels (MPE) were additionally blended. The polymer films were prepared using the casting film process, and their morphology, functional groups, water absorption, antibacterial, thermal, and mechanical properties were characterized using SEM, FTIR, water swelling test, disk diffusion method, DSC-TGA, and UTM. The results demonstrated the heterogeneity between the composites and the polymer matrix, and a lower polarity from the decreased %water swelling from 45% to …

Li5feo4 As A Cathode Prelithiation Additive : Doping Engineering And First-Principles Research, Zixiang Li, Zile Zou, Jialan Li, Chennan Ma, Jiarun Li, Xiaoyu Liu, Jin Yi, Jianhui Li

Journal of Metals, Materials and Minerals

During the initial charge-discharge cycle, irreversible loss of active lithium (~ 5% to 15%) severely affects the battery energy density and shortens cycle life of lithium‑ion batteries (LIBs). Prelithiation strategy has gradually become an effective approach to compensate for the irreversible loss of active lithium. Lithium ferrate (Li5FeO4, LFO) is considered to be a promising cathode prelithiation additive due to its high theoretical capacity (867 mAh·g‒1), suitable delithiation potential (3.5 V to 4.1 V), and competitive raw material. However, the application of LFO is limited by the its properties including poor air stability, low electronic conductivity, and incomplete delithiation. Currently, …

Synergistic Adsorption–Photocatalysis Of Activated Carbon/Titanium Dioxide Composite Derived From Rice Husk Ash Under Ultraviolet-C Irradiation, Bang-Tam Thi Dao, Do Trung Nguyen, Nhien Hon Le, Chi-Nhan Ha-Thuc

Journal of Metals, Materials and Minerals

Rice husk ash (RHA), an abundant biomass residue, was employed as a sustainable precursor for synthesizing activated carbon (AC) and its TiO2-based photocatalyst composite. AC was produced via ultrasonication-assisted NaOH activation of KOH-impregnated biochar, yielding a highly porous material with a large surface area. Titanium dioxide nanoparticles were synthesized from titanium (IV) isopropoxide (TTIP) and subsequently immobilized onto AC to form the AC/TiO2 composite. Structural and textural analyses (XRD, FT-IR, BET, SEM–EDS) confirmed the presence of anatase TiO2 uniformly distributed within the AC framework while preserving its porous architecture. The photocatalytic activity of the composite was assessed using Basic Blue …

Role Of Alkali And Alkaline-Earth Doped In Zeolite A-Derived From Industrial Waste Toward Direct Ethanol Dehydrogenation To Acetaldehyde, Darunee Sukchit, Malee Prajuabsuk, Chan Inntam, Saisamorn Lumlong, Bongkochawan Pakamwong, Auradee Punkvang, Duangkamol Gleeson, Pantita Trongjitraksa, Paramasivam Shanmugam, Supakorn Boonyuen, Niramol Juntarachat, Sasijuta Wattanarach, Parjaree Thavorniti, Bunjerd Jongsomjit, Pornpan Pungpo

Journal of Metals, Materials and Minerals

In this study, a sustainable catalytic route for converting ethanol into value-added acetaldehyde was developed using alkali- and alkaline earth-modified zeolite A synthesized from sugarcane bagasse ash (SCBA). Zeolite A was first prepared via alkaline fusion followed by hydrothermal crystallization and subsequently doped with 1 wt% K+ or Ca2+ using incipient wetness impregnation. Comprehensive physicochemical characterization (X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared spectroscopy (FTIR), nitrogen physisorption (N2 physisorption), ammonia temperature-programmed desorption (NH3-TPD), and carbon dioxide temperature-programmed desorption (CO2-TPD)) confirmed the formation of a highly crystalline LTA framework with tunable …

Graphene-Based Materials From Liquid Phase Exfoliation Of Graphite Using Mangosteen-Peel Extract : Experiments And Molecular Simulation, Piyaphat Thepphot, Narissara Karakate, Panu Danwanichakul

Journal of Metals, Materials and Minerals

The conventional Hummers method for graphene production requires large quantities of hazardous chemicals, causing environmental impacts and sustainability concerns. This study investigated mangosteen-peel extract as a natural alternative in liquid phase exfoliation of graphite, exploiting the structural similarity between condensed tannins and graphite, which enables π−π interactions. Four exfoliation processes were studied: shear force via a homogenizer (9,500 rpm and 14,000 rpm for 41 min), sonication using an ultrasound bath (200 W and 400 kHz) for 2 h and 3 h at 50℃ and their sequential combinations. The results confirmed successful graphite exfoliation yielding samples with I2D/IG ratios of 0.51 …

Sustainable Lightweight Foams From Hazardous Aluminum Dross, Chayapat Weerapakdee, Makoto Nanko, Yen-Ling Kuo, Sukasem Watcharamaisakul, Kaito Suzuki, Seiryu Suzuki, Siriwan Chokkha

Journal of Metals, Materials and Minerals

Aluminum dross is a hazardous byproduct from aluminum industry that causes environmental problems and high disposal cost. This work presents a sustainable route to upcycle secondary aluminum dross into lightweight ceramic foams for insulating refractory applications. Secondary aluminum dross powder was blended with polyethylene (PE) pore-forming agents (30 vol% to 70 vol%) and polyvinyl alcohol (PVA) binder added as a 7.5 wt% aqueous solution (binder contents: 1 vol% and 3 vol%), followed by pressing and sintering at 1400℃. Increasing PE systematically reduced bulk density and increased open porosity. At 70 vol% PE, the foams reached a bulk density of 0.94 …

Magnetocaloric Effect Of Gdtbdyerpr Rare-Earth High-Entropy Alloy, Yu Liu, Lei Gao, Jun Peng, Haitao Guo

Journal of Metals, Materials and Minerals

In this study, a GdTbDyErPr rare-earth high-entropy alloy (RE HEA) was successfully synthesized and its magnetic properties and magnetocaloric effect (MCE) were systematically investigated. The results indicate that the as-cast GdTbDyErPr RE HEA exhibits a single-phase hexagonal close-packed (HCP) structure with lattice parameters of a = 3.609 Å and c = 5.734 Å. Based on large parameter Ω, high mixing entropy (ΔSmix), and small parameters δ and εi, it can be inferred that the GdTbDyErPr alloy forms a disordered solid solution. The GdTbDyErPr RE HEA undergoes a first-order magnetic transition near about 143 K. The parameters |∆ |, RC, and …

Effect Of Zro2 Content And Oxide Additives On The Wear Resistance Of Pressureless-Sintered Si3n4 – Zro2 Composites, Kamol Traipanya, Thanakorn Wasanapiarnpong, Charusporn Mongkolkachit

Journal of Metals, Materials and Minerals

Silicon nitride (Si3N4) and zirconia (ZrO2) ceramics are well-known for their excellent wear resistance, high hardness, and high mechanical strength. This research focuses on the development and investigation of Si3N4–ZrO2 ceramic composites. Test specimens were fabricated by pressureless sintering at 1550-1650 oC for 2 hours in a nitrogen atmosphere, using SiO2, MgO, and Y2O3 as sintering additives. Density measurements indicated that the weight ratio of SiO2:MgO:Y2O3 at 3:3:5 promoted densification and improved with the addition of ZrO2 (3 mol% yttria-stabilized zirconia). However, the hardness of Si3N4 containing 5 wt% ZrO2 was 14.63 GPa and showed a decreasing trend as the …

Investigating The Effects Of Lamno. On The Morphology, Structural And Optical Properties Of Epoxy-Based Plastic Scintillators, Yeni Febrianti, Airine Hijrah Handayani, Marzuki Naibaho, Phahul Zhemas Zul Nehan, Zulkarnain -, Arbi Dimyati, Budhy Kurniawan

Journal of Metals, Materials and Minerals

Plastic scintillators are widely used in radiation detection due to their low cost, fast response, and ease of fabrication, although their performace is often limited by low density, low atomic number, make them less efficient for applications requiring high-energy radiation. In this study, LaMnO3 was synthesized using the hydrothermal method and employed as a dopant to enhance the optical and scintillation properties of epoxy-based plastic scintillators. Structural, morphological, and optical characterizations of LaMnO3 were carried out using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), UV-Vis and  photoluminescence (PL) spectroscopy. The results confirm that …