Search Results (195)

Research on raw materials for Al₂O₃-SiC-C refractory castables used in blast furnace troughs is relatively well established. However, gaps remain in both laboratory and industrial trials concerning the performance of castables incorporating SiC-modified flake graphite and alternative carbon sources. This study investigated the sintering behavior, mechanical properties, and service performance of Al₂O₃-SiC-C castables utilizing varying contents of modified flake graphite, pitch, and carbon black as carbon sources. Samples were characterized using SEM, XRD, and EDS for phase composition and microstructural morphology analysis. Key findings revealed that the thermal expansion mismatch between the SiC coating and flake graphite in SiC-modified graphite generated a microcrack-toughening effect. This effect, combined with the synergistic reinforcement from both components, enhanced the mechanical properties. The SiC modification layer improved the wettability and oxidation resistance of the flake graphite. This modified graphite further contributed to enhanced erosion resistance through mechanisms of matrix pinning and crack deflection within the microstructure. However, the microcracks induced by thermal mismatch concurrently reduced erosion resistance, resulting in an overall limited net improvement in erosion resistance attributable to the modified graphite. Specimens containing 1 wt.% modified flake graphite exhibited the optimal overall performance. During industrial trials, this formulation unexpectedly demonstrated a water reduction mechanism requiring further investigation. Full article

This study demonstrates the successful fabrication of high-performance reaction-bonded silicon carbide (RBSC) ceramics through an optimized liquid silicon infiltration (LSI) process employing multi-modal SiC particle gradation and nano-carbon black (0.6 µm) additives. By engineering porous preforms with hierarchical SiC distributions and tailored carbon sources, the resulting ceramics achieved a compressive strength of 2393 MPa and a flexural strength of 380 MPa, surpassing conventional RBSC systems. Microstructural analyses revealed homogeneous β-SiC formation and crack deflection mechanisms as key contributors to mechanical enhancement. Ultrafine SiC particles (0.5–2 µm) refined pore architectures and mediated capillary dynamics during infiltration, enabling nanoscale dispersion of residual silicon phases and minimizing interfacial defects. Compared to coarse-grained counterparts, the ultrafine SiC system exhibited a 23% increase in compressive strength, attributed to reduced sintering defects and enhanced load transfer efficiency. This work establishes a scalable strategy for designing RBSC ceramics for extreme mechanical environments, bridging material innovation with applications in high-stress structural components. Full article

The formation mechanism of black streak defects in hot-rolled steel sheets was investigated to address the influence of the process parameters on the surface quality during the production of 304 stainless steels. Macro-/microstructural characterization revealed that the defect regions contained necessary mold slag components (Ca, Si, Al, Mg, Na, K) which originated from the initial stage of solidification in the mold region of the continuous casting process, indicating obvious slag entrapment during continuous casting. On this basis, a three-dimensional coupled finite-element model for the molten steel flow–thermal characteristics was established to evaluate the effects of typical casting parameters using the determination of the critical slag entrapment velocity as the criterion. Numerical simulations demonstrated that the maximum surface velocity improved from 0.29 m/s to 0.37 m/s with a casting speed increasing from 1.0 m/min to 1.2 m/min, which intensified the meniscus turbulence. However, the increase in the port angle and the depth of the submerged entry nozzle (SEN) effectively reduced the maximum surface velocity to 0.238 m/s and 0.243 m/s, respectively, with a simultaneous improvement in the slag–steel interface temperature. Through MATLAB (version 2023b)-based reverse optimization combined with critical velocity analysis, the optimal mold slag properties were determined to be 2800 kg/m³ for the density, 4.756 × 10⁻⁶ m²/s for the kinematic viscosity, and 0.01 N/m for the interfacial tension. This systematic approach provides theoretical guidance for process optimization and slag design enhancement in industrial production. Full article

A novel bioactive glass–ceramic was developed using biogenic hydroxyapatite (BHA) synthesized from Rapana venosa (Black Sea) shells and monocalcium phosphate monohydrate [Ca(H₂PO₄)₂·H₂O] via solid-state synthesis. The prepared batches were obtained by combining BHA with SiO₂, B₂O₃, and Na₂O, melted at 1200 °C and melt-quenched in water to form glass–ceramic materials. Dense biogenic hydroxyapatite-based ceramics were successfully sintered at 1200 °C (2 h hold) using a 25 mass % sintering additive composed of 35 mass % B₂O₃, 45 mass % SiO₂, 10 mass % Al₂O₃, and 10 mass % Na₂O. Structural characterization was carried out using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The resulting materials consisted of a well-defined crystalline hydroxyapatite phase [Ca₁₀(PO₄)₆(OH)₂] alongside an amorphous phase. In samples with increased SiO₂ and reduced B₂O₃ content (composition 3), a finely dispersed Na₃Ca₆(PO₄)₅ crystalline phase appeared, with a reduced presence of hydroxyapatite. Bioactivity was assessed in simulated body fluid (SBF) after 10 and 20 days of immersion, confirming the material’s ability to support apatite layer formation. The main structural units SiO₄, PO₄, and BO₃ are interconnected through Si–O–Si, B–O–B, P–O–P, and mixed Si–O–Al linkages, contributing to both structural stability and bioactivity. Full article

This study analyzes a lacquered ear cup excavated from the Luobowan tomb complex in Guigang, Guangxi, attributed to the Nanyue Kingdom of the early Han dynasty. A range of analytical techniques, including optical microscopy (OM), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), pyrolysis–gas chromatography–mass spectrometry (Py-GC-MS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD), were employed to investigate the structural layers, material composition, and preservation state of the artifact. The lacquerware consists of four traditional layers: a wooden core, fabric reinforcement, lacquer ground, and lacquer film, reflecting Central Plains lacquerware techniques. The wooden core was identified as Phoebe sp., and the fabric layer is likely hemp, though fiber degradation limited exact identification. The lacquer ground layer contains natural lacquer mixed with SiO₂ from brick or tile powder. The lacquer film is a blend of Chinese and Vietnamese lacquer, with no synthetic additives or plant oils detected. The red lacquer layer contains cinnabar (HgS) as a pigment, while the black lacquer uses carbon black. Differences in moisture content between the red and black lacquer films are attributed to variations in surface porosity and pigment characteristics. This research provides valuable insights into Nanyue lacquer technology and preservation challenges. Full article

This study systematically analyzes the composition and microstructure of Neolithic pottery unearthed from the Dazhuzhuang, Likou, and Biting Sites in the Yongcheng District using techniques such as X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), infrared spectroscopy (IR), and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS). The results show that although the raw materials for pottery at the three sites were likely sourced from nearby ancient soil layers, significant differences in chemical composition and manufacturing techniques are evident. Pottery from the Dazhuzhuang Site is mainly composed of argillaceous gray pottery, with relatively loose raw material selection and a wide fluctuation in SiO₂ content (64.98–71.07%), reflecting diversity in raw material sources. At the Likou Site, argillaceous black pottery predominates, characterized by higher Al₂O₃ content (17.78%) and significant fluctuations in CaO content (1.46–2.22%), suggesting the addition of calcareous fluxes and the adoption of standardized manufacturing techniques. Pottery from the Biting Site mainly consists of argillaceous gray pottery, showing higher Al₂O₃ content (17.36%), stable SiO₂ content (65.19–69.01%), and the lowest CaO content (0.84–1.81%). The microstructural analysis further reveals that the black pottery (from the Likou Site) displays dense vitrified regions and localized iron enrichment. In contrast, the gray pottery (from the Dazhuzhuang and Biting Sites) shows clay platelet structures and vessel-type-specific differences in porosity. This research provides important scientific evidence for understanding raw material selection, manufacturing techniques, and regional cultural interactions in the Yongcheng area during the Longshan Culture period. Full article

The myogenic differentiation of muscle satellite cells (MuSCs) is an important biological process that plays a key role in the regeneration and repair of skeletal muscles. However, the mechanisms regulating myoblast myogenesis require further investigation. In this study, we found that STEAP3 is involved in myogenic differentiation based on the Yunan black pig MuSCs model in vitro using cell transfection and other methods. Furthermore, the expression of myogenic differentiation marker genes MyoG and MyoD and the number of myotubes formed by the differentiation of cells from the si-STEAP3 treated group were significantly decreased but increased in the STEAP3 overexpression group compared to that in the control group. STEAP3 played a role in iron ion metabolism, affecting myogenic differentiation via the uptake of iron ions and enhancing IRP-IRE homeostasis. STEAP3 also activated the PI3K/AKT pathway, thus promoting myoblast differentiation of Yunan black pig MuSCs. The results of this study showed that STEAP3 overexpression increased intracellular iron ion content and activated the homeostatic IRP-IRE system to regulate intracellular iron ion metabolism. Full article

This study presents a numerical investigation of surface plasmon resonance (SPR) sensors based on multilayer configurations incorporating BK7, silver, silicon nitride (Si₃N₄), and black phosphorus (BP). Using the transfer matrix method, the optical performance of four architectures was evaluated under refractive index perturbations consistent with values reported in prior theoretical and experimental studies. The sensor response was characterized through metrics such as angular sensitivity, resonance shift, full width at half maximum, attenuation, and derived figures including detection accuracy and limit of detection. Parametric optimization was performed for the thickness of each functional layer to enhance sensing performance. Among all configurations, those incorporating both Si₃N₄ and BP demonstrated the highest angular sensitivity, reaching up to 394.46°/RIU. These enhancements were accompanied by increased attenuation and spectral broadening, revealing trade-offs in sensor design. The results, based entirely on numerical modeling, provide a comparative framework for guiding SPR sensor optimization under idealized optical conditions. Full article

This study presents a black phosphorus-based surface plasmon resonance (SPR) biosensor for malaria detection, integrating silicon nitride (Si₃N₄) and single-stranded DNA (ssDNA) to enhance sensitivity and molecular recognition. The biosensor configurations were optimized through numerical simulations, evaluating metal thickness, dielectric layer thickness, and the number of black phosphorus layers to achieve maximum performance. The optimized system (Opt-Sys₄) exhibited high sensitivity (464.4°/RIU for early-stage malaria) and improved detection accuracy, outperforming conventional SPR sensors. Performance was assessed across malaria progression stages, demonstrating a clear resonance shift, increased attenuation, and enhanced biomolecular interactions. Key metrics, including the figure of merit, limit of detection, and comprehensive sensitivity factor, confirmed the sensor’s superior performance. Comparative analysis against state-of-the-art SPR biosensors further validated their capability for highly sensitive and specific malaria detection. These findings establish a promising plasmonic biosensing platform for early malaria diagnosis, potentially improving disease management in resource-limited settings. Full article

Fumed silica, a nanomaterial with a high specific surface area, excellent chemical stability, and electrical insulation, serves as an effective filler for rubber compounding. Compared to traditional carbon black, silica (SiO₂), the main component of fumed silica, improves the hardness and tear resistance of tread rubber, making it a viable substitute in some formulations. However, silica-filled compounds generally exhibit lower tensile properties and abrasion resistance than carbon black. Fumed silica, with its higher structural integrity, provides additional reinforcement points within natural rubber matrices, enhancing tensile strength and abrasion resistance. Studies demonstrate that replacing carbon black with an equivalent amount of fumed silica as the primary filler significantly improves tread rubber’s hardness (by 20%) and 300% tensile modulus (by 14%) while also reducing rolling resistance and enhancing wet skid performance. Fumed silica’s large specific surface area and low density (10–15% of conventional silica) make it challenging to use directly as a tread rubber filler due to dust formation and prolonged mixing times. This study developed a process combining fumed silica with deionized water, followed by drying and ball milling. This treatment reduces the material’s volume, forming a cohesive gel that, upon processing, minimizes dust and significantly decreases mixing time and difficulty. The interaction between the hydroxyl (–OH) groups on the surface of fumed silica and water molecules likely results in hydrated silica. This interaction enhances surface polarity and forms a hydration layer, improving the hydrophilicity and dispersion of fumed silica in rubber matrices. This reduces the shear modulus difference (ΔG′) between low and high strain, maintaining a consistent elastic modulus over a wide strain range. Such stability enables rubber to perform better under dynamic loads or in complex working conditions. The experimental results demonstrate that the hydration–ball milling process enhances the tensile strength of vulcanizates, improves the dispersion of fumed silica in rubber, strengthens the filler network, boosts dynamic performance, and enhances the wet skid resistance of tread rubber. Full article

The Ordovician/Silurian boundary (Wufeng/Longmaxi formations) in the Shizhu region, eastern Sichuan Basin, China hosts organic-rich black shales which are frequently interbedded with bentonite and hydrothermal minerals (e.g., pyrite). This study investigated the mineralogical, total organic carbon (TOC), total sulfur (TS), and major and trace element compositions of organic-rich samples. Non-visible volcanic input is identified to influence organic matter accumulation, as shown by the correlations between TOC and proxies, including Zr and Hf contents and the Cr/Al₂O₃, V/Al₂O₃, Ni/Al₂O₃, and SiO₂/Al₂O₃ ratios. Redox indicators (V/Cr, v/v + Ni, degree of pyritization (DOP), U/Th, and Mo contents) display positive correlations with TOC values, suggesting that an oxygen-depleted environment is necessary for organic matter (OM) preservation. The TOC values exhibit better regression coefficients (R²) against redox indicators, including DOP (0.43), U/Th (0.70), and Mo contents (0.62), than V/Cr (0.16) and v/v + Ni (0.21). This may because some V, Cr, and Ni is hosted in non-volcanic ashes within shales but not inherited from contemporaneous water columns. The greater scatter in TOC-DOP and TOC-Mo relative to TOC-U/Th relations may result from hydrothermal venting in shales, evidenced by the coexistence of framboid and euhedral pyrite and the previous finding of hydrothermally altered dolomites in the studied sections. There is no systematic relation between TOC and Ni/Co ratios, and this means that portions of Ni are contributed by non-visible volcanic ashes and Ni and Co are redistributed during the precipitation of hydrothermal pyrites due to their strong chalcophile affinities. Such a feature may further suggest that most pyrites are precipitated during hydrothermal venting. The DOP displays broad correlations with non-visible volcanic indicators, supporting that hydrothermal venting may be triggered by volcanic activities. The outcomes of this study highlight that caution is necessary when evaluating the sedimentary facies features of volcanism-affected organic-rich black shales with the used metallic proxies. Full article

Background: Shoulder impingement syndrome (SIS) is a prevalent condition among overhead athletes, often managed through therapeutic exercise interventions. However, the quality of reporting in exercise protocols significantly impacts their reproducibility and clinical implementation. The Consensus for Exercise Reporting Template (CERT) provides a standardized framework to assess the quality of exercise reporting in clinical research. Objectives: This systematic review aimed to evaluate the quality of exercise protocols used to treat SIS in overhead athletes by applying the CERT checklist. Additionally, the risk of bias was assessed to determine the methodological rigor of included studies. Methods: A systematic review was conducted following PRISMA guidelines. Six electronic databases (MEDLINE, CINAHL, Sport Discuss, Web of Science, and Cochrane) were searched for eligible studies. Inclusion criteria encompassed randomized controlled trials (RCTs), cohort studies, and case series that investigated exercise therapy for SIS in overhead athletes. Studies had to be published in English and provide details on exercise interventions. Exclusion criteria included non-human studies, acute injuries, and postoperative management. The primary outcome was the quality of intervention reporting, assessed using the CERT checklist. The secondary outcome was the risk of bias, evaluated using the modified Downs and Black checklist. Results: Five studies met the inclusion criteria, comprising four RCTs and one case series. CERT scores ranged from 6 to 13 (median = 8, IQR = 1), indicating suboptimal reporting quality. Commonly reported CERT items included equipment usage and exercise tailoring. However, key aspects such as adherence, motivation, and intervention fidelity were consistently underreported. None of the included studies provided comprehensive details on exercise interventions as per CERT guidelines, limiting their reproducibility and clinical application. Conclusions: The quality of reporting on exercise-based interventions for SIS in overhead athletes remains insufficient. Critical gaps in adherence monitoring, patient motivation, and intervention fidelity were identified. Future research should prioritize standardized and detailed reporting of exercise interventions to enhance reproducibility and facilitate evidence-based clinical practice. Full article

The present study developed a novel approach for transforming red mud (RM) into soft magnetic materials (SMMs) for applications in advanced electrical devices in the form of Fe-Si and Fe-Si-Al alloys. A total of ten blends were prepared based on two RMs, three iron oxide additives (Fe₂O₃, black and red mill scales), alumina and carbonaceous reductants in a range of proportions. Carbothermic reduction of the blends was carried out in a vertical Tamman resistance furnace at 1600–1650 °C for 30 min in an argon atmosphere; synthetic graphite was used as a reductant. Reaction products were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray fluorescence (XRF) and X-ray diffraction (XRD). Significant amounts of Fe-rich metallic droplets/regions of different grain sizes (0.5 to 500 μm) were produced in these studies. The formation of Fe-Si alloys with Si contents from 3.9 to 6.7 wt.% was achieved in 8 out of 10 blends; the optimal levels of Si for SMMs ranged from 3.2 to 6.5 wt.%. There was clear evidence for the formation of Fe-Si-Al (up to 1.8 wt.% Al) alloys in 4 out of 10 blends. In addition to lowering operating challenges associated with RM processing, blending of RMs with iron oxide additives and alumina presents a novel recycling approach for converting RMs into valuable SMMs for possible emerging applications in renewable energy, storage, electrical vehicles and other fields. Along with reducing RM stockpiles across the globe, this approach is expected to improve resource efficiency, mitigating environmental impacts while generating economic benefits. Full article

This study evaluated the colour and translucency changes in resin cements and lithium disilicate veneer restorations, as well as the sorption and solubility of cements after staining. Four resin cements (G-CEM ONE, RelyX Universal, Panavia V5, Variolink Esthetic) were tested. Cylindrical specimens and LiSi veneer restorations cemented to a G-aenial Universal Injectable dentine base (N = 10/group) were stained in black tea for 72 h. Changes in colour (∆E₀₀) and the translucency parameter (∆TP₀₀) were analyzed using a spectrophotometer, while sorption and solubility were calculated via mass/volume formulae. G-Cem and RelyX exhibited significantly lower ∆E₀₀ than Variolink and Panavia (p < 0.001), while RelyX uniquely showed increased ∆TP₀₀ (p < 0.001). The ∆E₀₀ of cemented veneers ranged from 2.7 ± 0.5 (G-Cem) to 3.9 ± 0.7 (Panavia), with decreased translucency after staining across groups (p > 0.05). The initial TP positively correlated with the ∆E₀₀ of both cements and veneer restorations, while the ∆E₀₀ of cements correlated with that of veneer restorations. RelyX had the highest sorption, and Variolink showed the highest solubility, though neither correlated with colour changes. Resin cements influenced colour changes in veneer restorations post-staining, with colour differences associated with initial cement translucency but independent of sorption and solubility. Full article

Tinted plasma electrolytic oxidized (PEO) coatings have been widely applied on the surface of Ti alloys in aerospace field. In this study, a black PEO coating was successfully developed on TC4 alloy, incorporating MoSi₂ nanoparticles in situ within the coating matrix to enhance its corrosion resistance. The results indicated that the incorporation of MoSi₂ nanoparticles noticeably influence the coating morphology. The pore size decreased while coating thickness decreased from 15 μm to 12 μm. The incorporation of MoSi₂ enhanced the barrier property of the inner PEO layer, as well as decreased the surface roughness and increased the coating hardness, which improved the corrosion resistance. The i_corr dropped to 1.49 ± 0.58 × 10⁻⁷ A/cm² after the incorporation of the nanoparticles. A black PEO coating with particle addition was suggested for broader application on Ti alloys. Full article