Journal of the Australian Ceramic Society最新文献

Zinc oxide (ZnO) structures are used in the field of environmental issues, especially photocatalysts, due to their superior physical and chemical properties. In this study, ZnO structures were produced using the hydrothermal technique. The physical and photocatalytic properties of the synthesized ZnO structures were investigated. The crystal size of ZnO was calculated using XRD patterns and found to be 27–36 nm using the modified Scherrer equation, 33–40 nm using the Williamson Hall model depending on the precursor amount. Scanning electron microscope (SEM) images of the produced ZnO structures revealed that it had a structure in the form of cauliflower morphology. Changing of the ZnO structure with decreasing precursor amounts clearly narrowed the band gap energy. Experimental studies of photocatalytic activity of ZnO photocatalysts were examined in a UV-cabinet, under Ultraviolet–A (UVA) light irradiation and by degradation of Rhodamine B (RhB) and Direct Red 23 (DR23) binary mixture of dyestuff against time. As a result of the experimental studies, it was observed that the photocatalytic activity of ZnO structure showed 97.16% higher degradation efficiency in 180 min. In line with kinetic studies, the photocatalytic half-life of the RhB + DR23 dyestuff was calculated between 31.79 min and 52.91 min for all structures, reaction rate constant (k) was calculated as highest 0.0218 1/min for Z 36.6 RhB degradation, and the regression coefficient (R²) values were calculated between 0.54 and 0.98 for all structures.

Conventional cancer therapies, while effective, are frequently associated with significant adverse effects owing to their lack of selectivity, impacting both malignant and healthy cells. To address these challenges, gold nanoparticles (AuNPs) have emerged as a promising platform for targeted drug delivery. Giant macroporous silica (GMS) is a recently developed material, with its drug delivery potential explored in only a single study to date. In this study, gold nanoparticles (AuNPs) synthesized using Thymus vulgaris (garden thyme) extract were incorporated into GMS, forming GMS-AuNPs. Additionally, AuNPs coated with chitosan (AuNPs@CS) were similarly loaded into GMS, resulting in GMS-AuNPs@CS composites. The synthesized materials were characterized through light microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The anti-cancer effects of GMS-AuNPs and GMS-AuNPs@CS were assessed against breast cancer cells using real-time cell analysis. Notably, no cytotoxic effects were observed on MCF-12 A normal breast epithelial cells at any of the tested concentrations. GMS-AuNPs demonstrated a dose- and time-dependent cytotoxic effect on breast cancer cells. These findings suggest that GMS-AuNPs hold promise as a potential therapeutic strategy for breast cancer treatment.

xPbO – (10-x)BaO – 40CdO – 50B₂O₃ where x = 0, 2.5, 5.0, 7.5 and 10 mol% (Pb0-Pb4) glasses have been synthesized using high purity grade of Pb₃O₄, BaCO₃, CdCO₃ and H₃BO₃. The density, molar volume, UV–visible, and infrared spectra have been investigated. The capability of such glasses as neutron and photon shielding materials was estimated via Phy-X/PSD program. With the addition of PbO the density increases, while the molar volume reduced. The average boron(:-)boron separation, optical packing density, the optical energy band gap and theoretical optical basicity (Λ_th) are calculated for all studied glasses. Mass-(MAC) and linear-(LAC) absorption coefficients of the investigated glasses were increased, while half-(HVL) value layer and mean-(MFP) free path were decreased as PbO content increased in the glass networks. The Pb4 glass introduced high MAC and having less HVL among all prepared glasses. The highest values of energy absorption buildup factor (EABUF) were performed for Pb4 sample in Compton scattering (CS) range. The values of fast neutron removal cross-section (FNRC) varied from 0.0548–0.0.0555 cm^− 1. Therefore, the Pb4 sample is a candidate for shielding the gamma ray ionizing radiation when compared with the other prepared samples.

Layered perovskite-like oxides with Ruddlesden-Popper (RP) phase structure are promising for high-technology industries, such as refractory, electronics, photonics, catalysis, and others. This work contributes to the advancement in the field of double-layered structures and reports a new double-layered compound La₂BaLu₂O₇. It is formed during solid-state reaction at 1200 °C through interaction of BaLu₂O₄ perovskite-like precursor with La₂O₃. No difference in the formation mechanism of the target phase was found, when using either BaO₂ or BaCO₃ as a starting component. The unit cell of crystallized La₂BaLu₂O₇ has a tetragonal symmetry (S.G. P4₂/mnm, (136)) with a = 6.04605 (65) Å, c = 20.8541 (44) Å, V = 762.32 (18) ų, Z = 4. The space group was selected based on a comparison of pycnometric (d_m = 7.65 ± 0.05 g /cm³) and X-ray (d_x = 7.64 g /cm³) densities. Indication data of the new compound are presented. The previously reported group of double-layered RP phases La₂BaFe₂O₇, La₂BaIn₂O₇, La₂BaSc₂O₇, La₂BaMn₂O₇ is supplemented by a new compound La₂BaLu₂O₇. The findings of this study may enhance the knowledge on double-layered RP phase structures and their potential applications.

This study investigates the effects of varying Si₃N₄ particle concentrations on the mechanical, wear, and flammability properties of additively printed Polylactic acid (PLA) composites with rice husk ash Si3N4 particles. The Si₃N₄ is extracted from rice husk through pyrolysis and nitration processes and found to be amorphous polycrystalline crystals with the Miller Indices plane of (110), (200), and (201) correspond to the diffraction peaks at 22.0, 26.7, and 33.69, respectively. The customized Polylactic acid -Si₃N₄ filaments were further prepared using a twin-screw extruder with varying volume ratio, and composites are printed using fused deposition modelling with specified infill ratios. According to results the composite C2, contains 1 vol% Si₃N₄ filler with a 75% infill ratio, exhibits superior mechanical properties, including the highest tensile strength of 34.2 MPa, flexural strength of 64.3 MPa, impact energy of 3.6 J, and hardness of 68 Shore-D. This enhancement is attributed to the optimal dispersion of Si₃N₄ particles, which promotes effective load transfer and minimizes stress concentrations. In contrast, specimen D2, with 2 vol% Si₃N₄ filler and a 75% infill ratio, demonstrates the best wear resistance and flammability performance, showing the lowest coefficient of friction of 0.18, minimal wear loss of 0.036 g, and the lowest flame propagation speed of 0.32 mm/min with “N0” ratings across all flammability categories, indicating excellent flame retardancy due to a denser structure and higher filler content. In thermal stability also the D4 composite performed well and stable at initial decomposition stages. Finally, scanning electron microscope (SEM) analysis further supports these findings, revealing that uniform filler dispersion as in C2 improves mechanical properties, while agglomerated particles as observed in suboptimal specimens lead to reduced performance due to localized stress points. The results highlight the potential of Si₃N₄-reinforced Polylactic acid composites in applications requiring enhanced mechanical, wear, and flammability properties.

This study investigates the effects of incorporating biogenic ceramic Si3N4 particles derived from wheat husk into castor sheath fiber-reinforced epoxy composites. The primary objective of this work is to determine the extent to which the reinforcing of stem fibers and the incorporation of biomass-extracted ceramic particles enhance the mechanical strength, wear resistance, and flame resistance of the composite material. The biogenic ceramic Si3N4 particles were produced by a thermochemical method and then subjected to surface treatment using silane. Subsequently, the treated particles are integrated into the composite material through the utilization of a hand layup technique. The results showed that adding 40 vol% castor stem sheath fiber and 2 vol% biogenic ceramic Si3N4 particles had a significant positive impact on the mechanical properties. Among the samples, ECS2 had the highest values for tensile strength (142 MPa), tensile modulus (5.05 GPA), flexural strength (175 MPa), flexural modulus (6.11 GPA), and Izod impact strength (5.24 kJ/m2), except for hardness. Incorporating biogenic ceramic Si3N4 particles into the ECS3 composite enhanced its wear resistance. The current wear rate of the object is 0.008 mm2/Nm, and its coefficient of friction (COF) is 0.31. The ECS3 exhibited the highest combustion rate of 6.54 mm/min in the flammability test. The utilization of biogenic ceramic Si3N4 particles derived from husks and the production of castor sheath fiber had significant impacts on the strength, wear resistance, and flammability of the composites, in comparison to those generated using leaf and fruit fibers. The findings emphasize the potential of biogenic ceramic Si3N4 particles -enhanced composites in several applications, including door panels in autos, defense armor manufacture, and interior panels for residential use.

This research delves into the properties of sintered ceramsite from muck, enhanced with municipal waste incinerated fly ash (MWIFA), using microwave sintering technology. It specifically investigated the effects of the MWIFA mix ratio, sintering temperature, and holding time on ceramsite’s key performance, including one-hour water absorption, porosity, and apparent density. The microstructural attributes were quantified through X-ray diffraction (XRD) and scanning electron microscopy (SEM), coupled with an evaluation of ceramsite’s capability to solidify heavy metals. The results demonstrate that ceramsite prepared with a 10% MWIFA ratio, sintered at 1100 °C, and maintained for a 15-minute holding period, exhibited optimal properties: a low one-hour water absorption rate of 0.2%, minimal porosity at 0.4%, and a substantial apparent density of 2.14 g/cm³. Furthermore, microstructural analyses confirm the existence of mineral phases including quartz, augite, andesine, albite, and labradorite. Significantly, the ceramsite showed high efficiency in immobilizing heavy metals, achieving solidification rates of 92% for Zn, 98% for Cu, and 100% for Cr. These findings offer valuable insights and serve as a practical guide for the recycling of MWIFA and muck, endorsing the use of microwave sintering technology in ceramsite production.

This study focuses on enhancing the mechanical characteristics and sustainability of flexible food packaging composites made from Polyvinyl Alcohol (PVA) reinforced with Pearl Millet Husk Biosilica and Areca Microfiber. The high silica content in biosilica from pearl millet husk provides excellent reinforcement, while areca microfiber improves the toughness and flexibility of the composite. Together, these natural fillers result in a stronger, more resilient, and environmentally friendly composite suitable for sustainable food packaging applications. The materials were processed by extracting biosilica from pearl millet husk through high-temperature calcination and chemical treatments, and areca microfiber was obtained through retting and drying of areca fruit husk. The composites were then fabricated using a solvent casting method. Mechanical testing revealed that specimen PAV1, with 1 vol% biosilica and 40 vol% areca microfiber, exhibited the best mechanical properties, including a tensile strength of 57 MPa, tensile modulus of 2.2 GPa, tear strength of 36 N/mm, and hardness of 37 Shore D, due to balanced filler dispersion, which enhances load transfer. Specimen PAV3, containing 4 vol% biosilica, showed superior performance in wear resistance with a wear rate of 0.005 mm³/Nm and COF of 0.23, dielectric properties with a permittivity of 4.95 and dielectric loss of 0.825, hydrophobicity with a contact angle of 91°, and thermal conductivity of 0.46 W/mK. These enhancements result from higher filler content that improves hardness, polarization, surface energy, and thermal pathways. SEM analysis confirmed the uniform distribution of fillers in PAV1, enhancing mechanical properties, while some agglomeration in PAV3, although creating stress points, contributed to enhanced wear and thermal properties. Overall, these composites offer a viable alternative for eco-friendly food packaging with improved mechanical, dielectric, and thermal properties.

In this study, near-infrared (NIR) spectroscopy, a measurement method not widely used in dentistry, was used to monitor the synthesis of calcium phosphate cement. Tetra calcium phosphate and di calcium phosphate dihydrate were mixed at a Ca/P ratio of 1.67, and water was added dropwise to induce the phase transition to HAp. The reaction conditions were evaluated by measuring NIR spectra every minute for 60 min and every 20 min for 24 h. The obtained NIR spectra were analyzed using singular value decomposition. The synthesized apatite was characterized by measuring XRD, FT-IR, and SEM. In the self-setting apatite cement system, 24-hour monitoring revealed that a phase transition was achieved. NIR monitoring was found to be effective and valuable for evaluating calcium phosphate cements.

The antitumoral activity, and in general, the biological activity is strongly altered by the low uptake of the active agents within the targeted cells. Therefore, lots of efforts have been made to ensure better cellular uptake by using specific carriers. In the present research we have obtained magnetic nanoparticles stabilized by polyethylene glycol (PEG) coating, and functionalized with aspartic acid, which is an important amino acid for protein synthesis and energy production in the body. Such decorated nanoparticles can be internalized by the tumoral cell due to their higher metabolic rate. The nanoparticles were used as a delivery system for antitumoral drugs as cisplatin, carboplatin or irinotecan in a Trojan Horse strategy. Based on the obtained results, it was found that aspartic acid can improve the internalization efficiency of the magnetic carriers after being loaded with antitumoral agents. The nanoparticles are quite stable, can reach and enter the mitochondria and organize around lipid vesicles in quite a high concentration, best results being obtained for the system loaded with cisplatin starting from 0.1 mg/mL.