Search Results (166)

Clarifying combustion-space behavior is essential for operating large-tonnage natural gas-fired float glass furnaces with complex single-furnace dual-cooler layouts. In this study, a three-dimensional computational fluid dynamics model of the gas-phase combustion space of a 1300 t/d natural gas-fired float glass furnace was developed and validated using crown-temperature measurements, with a maximum relative error of 3.3%. The effects of burner inclination angle (β = 5°, 10°, and 15°) and excess air ratio (α = 1.0–1.20) on temperature distribution, flame morphology, and flue-gas recirculation were investigated. The results show that β = 5° produces a more horizontally extended natural-gas jet, enhances contact with preheated air, and forms a wider high-temperature region, with a maximum temperature of 2512 K. Increasing the excess air ratio improves combustion completeness and enlarges the high-temperature region; however, further increasing α from 1.15 to 1.20 provides only marginal thermal benefits while increasing sensible heat loss through the exhaust gas. Among the investigated operating conditions, β = 5° and α = 1.15 achieve the lowest outlet flue-gas specific enthalpy of 755 KJ/Kg. Full article

It is shown that the empirical Williams–Landel–Ferry (WLF) and Vogel–Fulcher–Tammann (VFT) equations, as well as the semiempirical equations of other researchers, for the viscosity η in the glass transition region are, in fact, hyperbolic functions of temperature with corresponding relationships between their parameters. The hyperbolic dependence can be derived from the mathematically common expansion of lnη into a Taylor series in a small temperature parameter near the glass transition temperature, provided that the temperature range satisfies approximately (T − T_g)/T_g ≲ 0.1–0.15). The applicability of the principle of corresponding states for glasses of similar composition follows from this expansion. A new two-parameter equation in the form of a second-degree polynomial is proposed for ln(η) in the glass transition region. This equation contains physically significant parameters and adequately describes the available experimental data for individual glass-forming substances. The temperature range over which the proposed series expansion up to the third (quadratic in the small parameter) term is valid can be determined only experimentally, because the coefficients of the series depend on the nature of the glass. For the specific experimental data we used, the sharp temperature dependence of the viscosity in the glass transition region makes the quadratic polynomial applicable over almost the entire temperature range studied. Full article

This study evaluates the effect of decorative ceramic screen printing on the optical and photovoltaic performance of glass covers intended for building-integrated photovoltaics (BIPV). Nine ceramic-printed glass samples with different colors and optical densities were compared with a 4 mm Optiwhite reference glass and a bare silicon solar cell. The samples were characterized by UV-VIS-NIR spectrophotometry, energy-dispersive X-ray spectroscopy (EDS), and electrical measurements under simulated AM 1.5G irradiation at 1000 W/m². The optical results showed that the Optiwhite reference provided the highest transmittance, whereas the printed samples exhibited lower transmission, typically in the range of 60–80% in the visible region, depending on the coating type. Among the decorative variants, sample 1 showed the highest transparency, while sample 6 exhibited the lowest transmittance. The spectral behavior of the coated glasses indicates that the ceramic layers modify the photon flux reaching the solar cell through wavelength-dependent absorption and scattering effects. The photovoltaic measurements confirmed a clear relationship between decorative coating and electrical performance. Relative to the Optiwhite-covered reference cell, the printed samples showed power losses ranging from approximately 17% to 32%, with sample 1 achieving the highest maximum power among the decorative variants at 1.41 W, and sample 4 the lowest at 1.16 W. The main electrical effect of the ceramic coatings was a reduction in short-circuit current, whereas the open-circuit voltage remained nearly constant across the tested samples. EDS analysis identified the presence of ceramic-layer constituents associated with silica-, zinc-, titanium-, iron-, cobalt-, aluminum-, and fluorine-containing compounds, supporting the interpretation of vitrified decorative coatings formed during high-temperature processing. Overall, the results demonstrate that decorative ceramic printing can provide a practical compromise between architectural appearance and photovoltaic output when the optical density of the coating is appropriately controlled. Full article

The long-term success of implant-supported prostheses (ISPs) is strongly influenced by material selection, which affects stress distribution within the implant system and surrounding cortical bone. This study aimed to assess the biomechanical behavior of a four-unit ISP supported by two implants in the posterior region, using different framework and superstructure material combinations through dynamic finite element analysis (FEA). Methods: A three-dimensional (3D) edentulous mandibular model was created using Mimics software, with two implants placed in the first premolar and second molar regions. Four framework materials—titanium (Ti), glass fiber–reinforced composite (GFRC), 3Y-TZP zirconia, and polyether ether ketone (PEEK)—were combined with two superstructure materials, 5Y-TZP zirconia and resin-matrix ceramic (RMC), forming eight groups. Dynamic loading simulated chewing forces, and stress distribution was analyzed using the von Mises criterion. Results: The results demonstrated that 3Y-TZP zirconia frameworks generated the highest stress values across implants, abutments, and cortical bone. RMC crowns consistently produced lower stress than 5Y-TZP zirconia across all the groups. PEEK showed the highest displacement, followed by GFRC, zirconia, and Ti. Conclusion: Materials with higher Young’s modulus tended to exhibit greater stress transfer to the implant, implant components, and cortical bone. In contrast, polymer-based materials may show a tendency toward greater deformation and displacement compared with metallic and ceramic materials. Full article

To address wellbore instability and the technical challenges associated with high-density water-based drilling fluid loss control in deep shale gas formations of the Sichuan-Chongqing region in China, a novel nano-micro sealant designated CLG-Seal was synthesized via molecular structural optimization. The molecular structure of newly developed CLG-Seal exhibits distinct core–shell structural characteristics. The inorganic nano-silica constitutes the rigid core of CLG-Seal, which guarantees its plugging performance. The hydrophobically associating polymer which is coated on the surface of nano-silica constructs the flexible shell of CLG-Seal, endowing the CLG-Seal with excellent gel-forming capacity, adhesion film-forming capacity, deformability and perfect dispersibility. Transmission electron microscopy and scanning electron microscopy were employed to characterize the morphology of the CLG-Seal nanomicron-scale plugging agent. The sealing performance and underlying mechanisms of CLG-Seal were subsequently evaluated via particle plugging apparatus tests, displacement experiments, and etched glass micromodel simulations. Field trials conducted in the third section of Well WY3-2-3HF validated the application effectiveness of this agent in drilling fluid systems. The results indicate that the nano-micro sealant CLG-Seal exhibits a median particle size of D₅₀ is 146 nm, which can be modulated by adjusting the synthesis conditions. The nano-micro sealant CLG-Seal significantly mitigates fluid loss in low-permeability microfractures and fissures. Notably, a concentration of merely 3% is sufficient to achieve optimal nano-micro plugging performance. The results of the mechanism study indicate that while the CLG-Seal particles are close to each other, the polymer chains with flexible long chain structure which are coated on the surface of nano-silica constructs tend to be intertwined, forming a cross-linked network structure of gel film, thereby increasing the interaction between nano-micron particles and forming an impermeable plugging film. In addition, due to the nanoscale effect, the CLG-Seal has a strong tendency to adsorb onto the surface of shale rock through hydrogen bonding with the shale matrix. The hydrophobically associating polymer with high elastic modulus and excellent mechanical properties can enhance the pressure-bearing capacity of the filter cake through elastic deformation. Therefore, these nano-micron particles can form a strong sealing film on the filter cake and at the micropores of shale rock, thereby creating a dense mud cake on the outside of the shale formation. Field trial results demonstrate that the incorporation of the nano-micro sealant CLG-Seal into the drilling fluid for the third section of Well WY3-2-3HF reduced the PPA fluid loss to 4.6 mL. This value represents a substantial reduction compared to adjacent wells and signifies a remarkable improvement over the drilling fluids previously employed in the Longmaxi Formation of this block. Furthermore, the treated drilling fluid exhibited a superior filtration control pressure capacity of 10.5 MPa. The operation was completed successfully without any lost circulation or wellbore instability, and achieved a drilling footage of 42 h with an average penetration rate of 7.81 m/h. The mud weight was reduced by approximately 0.08–0.10 g/cm³ compared to offset wells. These results confirm the excellent application efficiency of the newly developed CLG-Seal in field operations. Full article

This article describes a study on the synthesis and annealing processes of thin-film coatings of vanadium oxide on flat, parallel substrates made of quartz glass, sapphire, and silicon, as well as optical fibers using an organometallic precursor, triisopropoxy vanadium (V) oxide. For the first time, optical constants of nanomaterials were estimated in real time during synthesis and subsequent annealed using the lossy-mode resonance effect. The coatings produced in an inert atmosphere after deposition were amorphous, comprising a mixture of VO₂, V₂O₅, V₆O₁₃, and V₃O₅. This method allowed for accurate determination of the threshold temperature for the transformation of oxide mixtures into a monocomponent phase. Optimal conditions for synthesis and annealing were determined for the production of vanadium dioxide (VO₂) and pentoxide (V₂O₅). Morphological changes in coated surfaces were observed as a result of heat treatment. The composition and properties of these samples were studied using optical, terahertz and Raman spectroscopy, as well as temperature-dependent analysis of electrical resistance. The morphology of the coating surface was determined using a scanning electron microscope and an atomic force microscope. The reduction of VO_x to VO₂ was studied in an atmosphere of hydrogen and argon during annealing after deposition, with its effectiveness being compared. It was shown for the first time that the reduction of higher vanadium oxides is due to the presence of elemental carbon in the volume of the material formed from a metalorganic precursor during growth of vanadium oxide. Coatings obtained by annealing in hydrogen had a smaller hysteresis loop width (~5 °C) during phase transition compared to coatings obtained by argon annealing (~9 °C). Both types of coatings demonstrated a 50–60% increase in transmission at 1 THz frequency and in the IR region, accompanied by a 10³–10⁴-fold change in electrical resistance. Full article

Monitoring air quality is crucial for understanding and improving public health. There is interest in developing ultra-sensitive, low-power, cost-effective sensors. This work demonstrates that structural modulation of Sn nanoparticles through controlled deposition and oxidation enables a transition from metallic to semiconducting percolative networks, significantly enhancing NO₂ sensing performance at room temperature. The proposed percolation-driven sensing mechanism provides a new framework for understanding charge transport and gas interaction in nanostructured metal oxide systems. The nanoparticles are deposited near the percolation threshold for electrical conduction and, upon exposure to air, consist of a tin core and an amorphous Sn₃O₄ surface. Post-deposition heating in air at 320 °C for two hours forms SnO and Sn₃O₄ on top of the gold electrodes and polycrystalline SnO in the tetragonal litharge phase, known as Romarchite, on the glass between the electrodes. Both as-deposited and heat-treated sensors were capable of detecting NO₂ at room temperature, with a limit of detection in the parts-per-billion range. A percolation model is used to explain their operating currents, in which NO₂ reacts at nanoparticle gaps and intra-grain boundaries to form charge-depletion regions that primarily determine their resistance. Heat treatment has also been found to cause disproportionation of SnO, resulting in tin-rich precipitates and increasing the operating current to the milliampere range. These precipitates, although oxidized on their surfaces when exposed to air, may serve as bridges that reduce the total resistance of the percolating paths. Full article

Permeability evolution in hydrate-bearing porous media is a key factor controlling gas production efficiency during natural gas hydrate exploitation. In this study, laboratory experiments were conducted using sand-packed tubes filled with quartz sand and glass beads to systematically investigate the variation of liquid-phase permeability with hydrate saturation. The effects of pore structure, particle size, and initial gas injection pressure on hydrate formation and permeability reduction were analyzed. Furthermore, experimental results were compared with four commonly used permeability models, including the Kozeny model, the Dai model, the Masuda model, and the parallel capillary model. The results show that permeability decreases continuously with increasing hydrate saturation in both porous media, and the most rapid decline occurs at low saturation levels between 0 and 9%. Under the same conditions of 20–40 mesh and an initial pressure of 6.0 MPa, the pressure drop rate in the quartz-sand-packed tube reaches 1.062 kPa per minute, which is about 2.35 times higher than the 0.451 kPa per minute observed in the glass-bead-packed tube, indicating a faster hydrate formation rate and stronger permeability reduction in quartz sand. In addition, both increasing particle mesh size and raising the initial gas injection pressure significantly promote methane consumption and hydrate formation. Model comparison results demonstrate that permeability reduction is strongly dependent on pore structure. The Kozeny pore-filling model, the Dai model (M = 3), and the Masuda model (N = 8) show good agreement with the glass-bead data, whereas the Dai model (M = 8), the Masuda model (N = 15), and the pore-center form of the parallel capillary model better describe the quartz-sand system. In contrast, models based on particle-surface coating show poor agreement in both media. These findings indicate that permeability reduction is primarily controlled by pore-space occupation and flow-path restriction rather than uniform surface coverage. The results suggest that hydrate growth is more likely to occur in pore centers and critical pore-throat regions, although this conclusion is based on macroscopic model comparison and requires further validation by pore-scale observations. This study provides a quantitative basis for model selection and improves the understanding of permeability evolution in hydrate-bearing porous media. Full article

With non-rainfall water (NRW), principally dew and fog, serving as an important water source, especially in arid and semiarid regions, factors that may increase the NRW yield may have important hydrological and ecological consequences. On the other hand, dew and fog may also have hazardous effect on inorganic and human-made materials that may undergo corrosion and/or degradation. It has long been noted that dew and fog are affected by neighboring objects, the effect of which was, however, only barely explored. Hypothesizing that it may principally be linked to the sky view factor (SVF) (determining, in turn, substrate temperature and heat flow) and, therefore, to the angle that is formed between the collecting substrate and the height of the neighboring objects, a set of square boxes (30 × 30 or 60 × 60 cm) was constructed. The boxes had variable heights, forming angles of 15°, 30°, 45°, 60°, and 75° between 6 × 6 × 0.1 cm cloth attached to a substratum (10 × 10 × 0.2 cm glass plate overlying 10 × 10 × 0.5 cm plywood) at the center of each box and the top walls of the box. NRW that accumulated at the cloths was compared with cloths placed in the open, serving as control. Another set served to measure the plate temperatures. A clear decrease in NRW, with an angle corresponding to a third-degree polynomial equation, was found (r² = 0.998). Taking 0.1 mm as the threshold for vapor condensation (dew), and taking the average maximal NRW as measured for two years in the Negev (0.20 mm), angles of ≥45° will suffice to impair condensation. However, with the projected decrease in NRW with global warming, even angles of ≥30° may impair condensation in 1–2 decades. While it may decrease the dew amounts and subsequently negatively affect the vegetation in forest clearings and wadis or canyons, it may decrease the exposure of construction materials to corrosion and/or degradation, thus exerting a positive effect on construction materials in urban settings. Full article

Background/Objectives: Staphylococcus epidermidis (RP62A) and Staphylococcus aureus (UAMS-1) are clinically relevant pathogens frequently implicated in implant-associated infections due to their ability to form biofilms. RP62A is typically linked to persistent, chronic, low-grade infections, whereas UAMS-1 is associated with acute, invasive disease. Both strains serve as representative models for chronic and acute periprosthetic joint infections (PJIs). The objective of this study was to examine and compare in vitro biofilm formation by RP62A and UAMS-1 on orthopaedic materials/disc surfaces of defined composition. Methods: In vitro biofilm formation assays were performed using orthopaedic disc surfaces composed of cobalt–chromium alloy (CoCr), titanium alloy (Ti), and polyethylene (PE) after 72 h of incubation. Biofilm biomass was quantified using crystal violet staining, with absorbance measured at OD₅₇₀. A polystyrene (PS) surface served as a control. Additionally, retrieved orthopaedic explant components were used as substrates for in vitro biofilm assays, in which RP62A was incubated for 72 h on the explanted surfaces. Supporting assays on glass slides were conducted to examine strain-specific biofilm-related architecture. Results: In vitro biofilm mass quantification assays showed strong biofilm formation by RP62A across all tested surfaces, with the highest absorbance on CoCr (OD₅₇₀ = 5.80 ± 0.19). Notably, biofilm formation on CoCr was 76% higher compared to PS (p < 0.0001). No significant differences were observed among all three surface discs (p > 0.1). Biofilm formation was highest on PE for UAMS-1 (OD₅₇₀ = 1.29 ± 0.09) and was significantly greater than on Ti (178%, p < 0.001) and CoCr (196%, p < 0.0001). In the in vitro assays performed on retrieved explant components, RP62A showed pronounced biofilm accumulation on polyethylene tibial inserts, particularly in regions of mechanical wear and friction. Supporting assays on glass slides were performed to examine strain-specific surface microstructural, revealing dense network-like structures for RP62A and thinner, discontinuous layers for UAMS-1. Conclusions: RP62A formed dense biofilms in vitro on multiple orthopaedic implant materials and retrieved explant components, consistent with its association with chronic periprosthetic joint infections. Increased biofilm accumulation was observed on mechanically worn polyethylene surfaces. In contrast, UAMS-1 showed lower biofilm formation on metallic disc surfaces, indicating strain- and material-dependent differences. These findings highlight the relevance of implant material selection and surface integrity for strategies targeting biofilm-associated implant infections. Full article

In this study, the Nd:YAG laser process was employed with preselected welding parameters and varying initial welding temperatures (including room temperature, 10 °C, and 0 °C) for spot welding of (Zr₅₃Al₁₇Co₂₉)Nb₁ bulk metallic glass. Following welding, the microstructure—including the parent material, heat-affected zone (HAZ), and weld fusion zone (WFZ)—as well as the microhardness, thermal properties, and corrosion resistance of the welds, were systematically investigated. Owing to the low glass-forming ability of the alloy, a small amount of Zr₆CoAl₂ phase was observed within the amorphous matrix at the center of the bulk metallic glass cast plate. After the laser welding, sub-micron or nanoscale Zr(Al_xCo_1−x)₂ phases have formed in the HAZ of all welded samples, which significantly influenced the microhardness, thermal properties, and corrosion resistance in this region. As the initial welding temperature decreased, both the volume fraction and the density of the Zr(Al_xCo_1−x)₂ phase were reduced. Notably, for the weld performed at the lowest initial temperature of 0 °C, small crystalline phases were detected only at approximately 70 μm below the surface of the HAZ. To clarify the effect of IWTs on corrosion resistance, welded samples were immersed in 6 M HCl at 35 °C for 72–120 h. Surface morphologies after corrosion were examined by SEM in the PM, HAZ, and WFZ. No evident pitting was detected after 72 h of immersion. After 120 h, pitting corrosion was observed on the HAZ surfaces of welds subjected to RT and 10 °C IWTs, whereas no obvious pitting was found at an IWT of 0 °C. The pit size and density in the HAZ increased with increasing IWT. In contrast, no pitting was observed in the WFZ under any IWT condition. Full article

Bulk metallic glasses exhibit unique viscoplastic flow behavior within their supercooled liquid region. Their high-temperature deformation mechanisms diverge markedly from the highly localized deformation at room temperature. This contrast offers a critical window for investigating their compressive flow models and assessing their forming potential. This study aims to systematically reveal the high-temperature compressive flow behavior of bulk metallic glasses within the supercooled liquid region and to establish a corresponding flow model. Through constant strain rate high-temperature compression experiments conducted on Zr₅₆Co₂₈Al₁₆ bulk metallic glass within its supercooled liquid region, the variations in flow stress, crystallinity, and surface deformation characteristics with temperature were systematically investigated. The results indicate that the compressive behavior of the bulk metallic glass exhibits significant temperature dependence within this temperature range. The compressive strength decreased from 689 MPa at 487 °C to 330 MPa at 507 °C, and then increased to 435 MPa at 527 °C. The angle between the fracture/bulging direction and the loading direction increased from 45° at 487 °C to 88° at 507 °C, and then decreased to 60° at 527 °C. The shear band average spacing increased from 1.797 μm at 487 °C to 2.060 μm at 507 °C, and then decreased to 1.189 μm at 527 °C. These results consistently indicate that the plastic deformability is optimal at a compression temperature of around 510 °C. By integrating the analysis of mechanical curves and morphological characteristics, the applicability of three deformation mechanisms was evaluated: highly localized shear banding, homogeneous viscoplastic flow, and dynamic structural relaxation hardening. A constitutive relationship between compressive strength and temperature was established, which accurately describes their correlation. Simultaneously, it reveals that the dominant deformation mechanism evolves through highly localized shear banding and homogeneous viscoplastic flow, ultimately transforming into dynamic structural relaxation hardening as the temperature increases. This study provides theoretical guidance for predicting the compressive flow behavior of bulk metallic glasses in the supercooled liquid region and offers critical model support for precisely controlling their thermoplastic forming processes. Full article

Lunar dark mantle deposits (DMDs), formed by explosive volcanic activity on the Moon, are typically composed of glass- and iron-rich pyroclastic materials, with slight variations in color, crystallinity, and TiO₂ concentration by region. This paper proposes a method for identifying DMDs using the YOLOv8 deep learning model, enhanced by the introduction of a multi-scale feature extraction (MSFE) module with an attention mechanism, which improves the model’s ability to detect targets at different scales. First, a DMD dataset was constructed using Lunar Reconnaissance Orbiter (LRO) data, with manual annotations of DMD regions and lunar image slicing to optimize computational efficiency. The YOLOv8 architecture, with the incorporated MSFE module, was then used to improve model accuracy in complex terrain. The experimental results showed that the improved DM-YOLO model achieved a precision (P) of 83.9%, a recall (R) of 83.2%, and a mean average precision (mAP@0.5) of 84.2%, representing increases of 15.2%, 14.4%, and 14.0%, respectively, over those obtained with the original YOLOv8 model. The predicted results were preliminarily verified using FeO abundance data and further confirmed by analysis of M³ spectral absorption features, showing strong consistency with known DMDs in terms of both chemical composition and mineralogical characteristics. Observations showed that DMDs were located primarily in the low- and mid-latitude regions of the Moon, with most deposits found in the lunar highlands. The findings suggest that the DM-YOLO model has significant potential for providing technical support for lunar exploration and resource development, particularly for identifying small-scale features that are difficult to annotate. Full article

This study investigates the mechanical performance and surface morphology of polyamide-based materials commonly used in plastic injection molding. Two resins, PA6 and PA66, were analyzed in both neat and 20 wt% glass fiber-reinforced (GF20) forms. The influence of reinforcement and material type on tensile strength and ductility was examined through integrated experimental and numerical approaches, complemented by microstructural and elemental analyses. PA6 and PA66 specimens were produced in accordance with ISO 527, and tensile tests revealed a significant increase in elastic modulus and tensile strength with glass fiber reinforcement, accompanied by a reduction in elongation at break. Flammability was evaluated via Glow Wire and Tracking tests. SEM–EDS analyses provided insights into fracture morphology and elemental distribution, showing that fiber–matrix interfacial debonding and fiber pull-out dominated failure in reinforced specimens, whereas neat polymers exhibited homogeneous surfaces. Finite element simulations performed in ANSYS Explicit Dynamics supported the experimental findings by identifying stress concentration zones and failure initiation regions. Although numerical simulations successfully captured stress distribution trends, quantitative differences were attributed to idealized modeling assumptions and processing-induced microstructural effects. Overall, this work provides a comprehensive assessment of the reinforcement effects in PA6 and PA66 systems, offering valuable guidance for material selection and design optimization in polymer-based engineering components. Full article

We report on the fabrication and characterization of InGaN-based ridge-waveguide laser diodes employing spin-on-glass (SOG) as the insulation and planarization layer. In contrast to conventional silicon dioxide (SiO₂) isolation deposited by PECVD, the SOG approach provides improved surface planarity, reduced processing complexity, and lower fabrication cost. The laser structures were grown on GaN substrates by MOCVD, with the active region consisting of In_0.11Ga_0.89N quantum wells. Following ridge formation and SOG deposition, an etch-back process was used to form the electrical contacts. We have demonstrated the formation of high-quality insulating surfaces with strong adhesion to the ridge sidewalls. When using a Ni protective layer, the fabricated devices exhibited favorable electrical and optical characteristics and achieved stable laser operation under both pulsed and continuous-wave conditions. These results indicate that the SOG-based insulation process represents a promising alternative for the scalable and cost-effective fabrication of InGaN laser diodes targeting advanced photonic applications. Full article