Search Results (3,239)

The effect of Mn addition on the structural, dielectric, ferroelectric, and mechanical properties of Bi_0.5Na_0.5TiO₃ (BNT) and 0.94(Bi_0.5Na_0.5TiO₃)–0.06(BaTiO₃) (BNT–BT) ceramics was systematically investigated under identical processing conditions. Powders were calcined at 750 °C for 2 h and 900 °C for 2 h, followed by sintering at 1060 °C for 5 h. Mn contents of 0.5 and 5 mol% were selected to represent low-level substitution and near-saturation regimes. XRD confirmed single-phase perovskite formation within laboratory detection limits, while Raman spectroscopy revealed Mn-induced lattice distortions. Low Mn addition (0.5 mol%) enhanced densification and improved remanent polarization in BNT–BT (Pr = 33.5 μC/cm²). In contrast, 5 mol% Mn promoted grain coarsening, increased porosity, and reduced functional performance. Mechanical properties evaluated using two-parameter Weibull statistics showed composition-dependent variations in characteristic hardness and elastic modulus. The results demonstrate that Mn-doping effects depend strongly on both dopant concentration and host-lattice structural state, distinguishing beneficial substitution from defect-saturation behavior in lead-free BNT-based ceramics. Full article

Comparative analysis of nanostructured multilayer Cr/(Cr/a-C)ml coatings on HS6-5-2 steel was carried out. The coatings were deposited at various chromium target power values using PVD technology, particularly the magnetron sputtering method. The effect of different technological regimes on the properties of the nanostructured multilayer Cr/(Cr/a-C)ml coatings was studied. Identical characterization methods were used for the three types of coatings obtained. Cross-sections of the coated samples were prepared in order to directly determine the thickness of the resulting coatings, their uniformity, and the presence of defects or imperfections, both at the substrate–coating interface and within the coatings themselves. Calotest and Daimler-Benz adhesion test were also performed to evaluate the coated layers’ thickness and evaluate their adhesion strength. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses were carried out to define the chemical composition of the multilayered coatings. To evaluate the hardness and modulus of elasticity of the resulting coatings, nanoindentation measurements were also conducted. The data obtained under the three different deposition regimes were analyzed and compared, which allowed us to assess the influence of the chromium target power during the deposition process on the properties of the obtained coatings. Full article

We study a rigidity problem for functions $F:{\mathbb{R}}_{>0}\to {\mathbb{R}}_{\ge 0}$ that penalize deviation of a positive ratio from equilibrium $x=1$. Assuming (i) a d’Alembert-type composition law on ${\mathbb{R}}_{>0}$, and (ii) a single quadratic calibration at the identity (in logarithmic coordinates), we prove that F is uniquely determined. The composition law implies the normalization $F\left(1\right)=0.$ The unique solution is called the canonical reciprocal cost, namely the difference between the arithmetic and geometric means of x and its reciprocal. Our proof uses the logarithmic coordinates $H\left(t\right)=F\left(e^t\right)+1$, where the composition law becomes d’Alembert’s functional equation on $\mathbb{R}$. The calibration provides the minimal regularity needed to invoke the classical classification of continuous solutions and fixes the remaining scaling freedom, selecting the hyperbolic-cosine branch. We also establish the necessity of each assumption: without calibration the composition law admits a continuous one-parameter family; without the composition law the calibration does not determine the global form; and without regularity the composition law admits pathological non-measurable solutions. Finally, we establish a stability estimate for approximate solutions under bounded defect and characterize some properties of the canonical cost. Full article

This review systematizes data on the phase composition and key properties of compounds in the W–B system, including thermodynamic stability, crystal structure, and hardness. The current understanding of the binary W–B phase diagram and the stability of individual borides is discussed, alongside the influence of defects and non-stoichiometry on their properties. The main methods for synthesizing these materials and producing coatings based on them are summarized. Potential applications of tungsten borides are highlighted, particularly for high-temperature environments, cutting tools, and protective and functional coatings. Finally, key directions for future research are outlined, focusing on the refinement of phase equilibria, the scaling of production methods, and the development of W–B-based materials with tailored performance characteristics. Full article

The replacement of petroleum-based plastics with sustainable and biodegradable materials remains a critical challenge for food packaging and biomedical applications. Gelatin is an attractive natural biopolymer for film fabrication; however, its inherent brittleness, moisture sensitivity, and limited structural stability restrict practical use. In this work, for the first time, low-power direct-probe ultrasonication is introduced as a green and additive-free strategy to regulate molecular organization and enhance the performance of gelatin–glycerol composite films. Systematic variation in ultrasonic power and treatment duration revealed a strong dependence of film structure and properties on processing conditions. Low-power ultrasonication (20 W) promoted gelatin–glycerol interactions, induced a transition from loosely organized molecular arrangements to helix-like molecular packing at the nanometer scale, and produced smooth, compact microscale surface morphologies. As a result, these films exhibited enhanced hydrophilicity, reduced surface defects, and improved thermal stability. In contrast, high-power ultrasonication generated excessive cavitation, leading to large-scale porous structures and diminished thermal and surface performance. Therefore, this work identifies a distinct low-power ultrasonic window that enables controlled molecular reorganization and hierarchical structure formation in gelatin–glycerol systems. Structural and physicochemical analyses using SEM, FTIR, XRD, water contact angle measurements, and thermogravimetric analysis collectively elucidate the ultrasound-driven structure–property relationships within the gelatin–glycerol matrix. Overall, this study demonstrates that controlled ultrasonication enables precise tuning of gelatin-based film architecture and properties, offering a scalable and environmentally friendly route to high-performance biodegradable materials for sustainable packaging and biomedical applications. Full article

Accurate crack segmentation in civil infrastructure imagery remains challenging because of the prevalence of thin, low-contrast, and spatially discontinuous defects that often appear amid textured surfaces, shadows, and acquisition noise. Although Transformer-based models improve global context modeling, many existing solutions incur substantial computational and memory overhead, which limits their use in practical, resource-constrained inspection settings. In this work, we introduce an efficient hybrid segmentation architecture that combines a convolutional encoder for high-fidelity local representation with a lightweight Transformer bottleneck for global dependency modeling, followed by a progressive decoder that restores spatial resolution through multi-level skip-feature fusion. To better accommodate severe foreground sparsity and preserve fine crack structures, the framework is trained with a composite Dice–Binary Cross-Entropy objective and employs a tokenization strategy designed to preserve fine spatial details while enabling efficient global context modeling. We validate the proposed approach on four public benchmarks, demonstrating consistent improvements over representative convolutional, Transformer-based, and hybrid baselines, while ablation studies confirm the contribution of each design component. Finally, runtime profiling shows favorable latency and memory characteristics, supporting real-time or near real-time deployment on embedded and edge inspection platforms. Full article

Defect-tolerant oxide ceramics offer an alternative reinforcement strategy for high-performance polymer composites beyond conventional silica- and zirconia-based systems. In this work, a novel BaZrO₃-Y₂O₃-SrTiO₃ (BZYS) ceramic hybrid was introduced as a reinforcing phase in a polyetherimide (PEI) matrix to evaluate its effect on interphase formation, thermal stability and mechanical performance. BZYS powders were prepared by ball milling and incorporated at 1 and 3 wt% into solution-cast PEI films. X-ray diffraction confirmed the preservation of the BaZrO₃ perovskite structure after mechanical activation, with a slight lattice expansion, indicating partial ion incorporation and defect-mediated structural accommodation. SEM analysis revealed predominantly submicron agglomerates with homogeneous dispersion at low loading and controlled agglomeration at higher content. Differential scanning calorimetry demonstrated a systematic increase in glass transition temperature from 202.0 °C for neat PEI to 210.4 °C and 212.0 °C for 1 wt% and 3 wt% composites, respectively, evidencing restricted segmental mobility and interphase formation. Instrumented microindentation showed substantial hardness enhancement of 40% and 83% for 1 wt% and 3 wt% reinforcement, respectively (p < 0.05), with a strong linear dependence on filler content (R² = 0.9845). The results demonstrate that chemically stable, strain-tolerant BZYS ceramics effectively promote interphase-mediated reinforcement in PEI, establishing a novel oxide-based pathway for mechanically enhanced dental composite materials design. Full article

Bone regeneration focuses on the creation of functional tissue to repair bone defects. Creating a biodegradable scaffold hydrogel that combines a hemostatic agent with bioactive ceramics can afford the biological and mechanical benefits of both components. In the present study, we developed an injectable gelatin–alginate dual-composite hydrogel, loaded with two functional fillers: hydroxyapatite (HA) and the hemostatic agent montmorillonite (MMT). HA (microparticles and nanoparticles) was incorporated at concentrations of 10–30 mg/mL, with and without MMT at 20 mg/mL. The effects of functional fillers and their concentration on the microstructure and resulting physical and mechanical properties were studied, and a qualitative model summarising these effects was developed. All formulations exhibited clinically appropriate gelation times (5–29 s). n-HA significantly prolonged gelation time, reaching 29 ± 3 s at 30 mg/mL, while MMT reduced gelation time at all concentrations. The tensile strength of the unloaded hydrogel reached 20 kPa and increased to 57 kPa with 30 mg/mL of n-HA. The tensile strength even increased further with the addition of MMT (77 kPa). The results indicate that the combination of HA and MMT produced dual micro-composite hydrogels with moderate reinforcement, whereas the combination of n-HA and MMT generated dual nano–micro composites with combined reinforcing effects. The latter exhibited the highest strength and sealing ability while maintaining clinically relevant gelation times and controlled swelling behaviour. In conclusion, the combination of MMT with n-HA or HA enables the creation of functional hydrogels with controlled properties, tailored to specific applications in bone regeneration. Full article

The electrochemical reuse of spent graphite from the negative electrodes of lithium-ion batteries is influenced by regeneration-induced changes in near-surface chemical and defect states. These states govern solid electrolyte interphase (SEI) re-formation, particularly when bulk contaminants are suppressed. Acidic malic-acid leaching and ethylenediaminetetraacetic acid chelation under alkaline conditions (pH 8.7) were compared under similar operating parameters to isolate the role of the leaching environment. This was followed by heat treatment at 1200 °C to decouple chemical cleaning from structural restoration. Both methods reduced the total impurities from 217.85 ppm to ~1.8 ppm, approaching that of commercial graphite. Despite the comparable bulk purity, depth-resolved X-ray photoelectron spectroscopy after formation cycling revealed distinct outermost surface states relevant to SEI re-formation: acidic processing yielded a more oxygenated carbon signature and higher LiOH fraction at the outermost surface (~16%), whereas alkaline chelation produced a more graphitic, carbonate-dominated surface with lower LiOH (~7%). Electrochemical and impedance measurements were consistent with these differences, suggesting that after the bulk impurities were minimized, resistance development was largely governed by the leaching-conditioned near-surface state, which biased the SEI composition. The comparison under matched conditions linked the regeneration environment to SEI-relevant surface speciation and provided a mechanistic basis for selecting regeneration routes to reuse spent graphite as a negative-electrode active material. Full article

Duplex-phase low-density steels are attracting interest for lightweight structural applications, as reducing vehicle mass is an effective route to lower fuel consumption and emissions. This review summarizes recent progress in alloy design, processing, microstructure control, and performance of duplex-phase low-density steels. The roles of major alloying elements are discussed in terms of phase stability and precipitation tendency, followed by an overview of typical processing routes from melting to hot and cold rolling and subsequent heat treatments used to tailor phase fractions and defect structures. Strengthening mechanisms are reviewed with emphasis on precipitation control, including the beneficial contribution of fine intragranular κ′ precipitates and the ductility penalty associated with coarse intergranular κ* films, as well as the use of B2-based particles for high specific strength. Deformation behavior is then discussed in terms of transformation-/twinning-induced plasticity (TRIP/TWIP), planar versus wavy slip, and strain partitioning between ferrite and austenite. Finally, key challenges are outlined, including quantitative interface-based mechanism description, gaps in service property data, stable industrial production and compositional uniformity, and the development of forming and welding windows for engineering implementation. Full article

The study aims to strengthen cylindrical liners by plasma electrolytic oxidation (PEO) and to determine the optimal processing parameters for forming wear-resistant coatings. The results of laboratory experiments were transferred to practical application for liner strengthening, followed by testing coatings formed directly on real components. PEO was applied to cylindrical sleeves made of eutectic aluminum–silicon alloy EN AC-48000 to form mechanically strong and wear-resistant oxide coatings. The coating had a two-layer structure: a dense inner barrier layer and a porous outer layer. The effect of SiO₂ (~20 nm) and Al₂O₃ (~30 nm) nanoparticles in the electrolyte on the morphology, phase composition, microhardness and tribological characteristics of the coatings was evaluated. The optimal PEO parameters were determined as 325 V, duty cycle 25%, processing time 12 min, average current density 1.4 A·dm⁻², and concentration of Al₂O₃ + SiO₂ (5 + 5 g L⁻¹). Under these conditions, the coating achieved a maximum microhardness of 259 HV, a low coefficient of friction of ~0.50 and a wear rate of 0.81 × 10⁻⁴ mm³·N⁻¹·m⁻¹. X-ray diffraction analysis confirmed the formation of γ-Al₂O₃ without changing the silicon phase. The results provide quantitative data on the effects of nanoparticles and PEO parameters on coating properties, which is important for the development of long-life part surfaces. The increased microhardness and wear resistance are attributed to the formation of the ceramic γ-Al₂O₃ phase and the densification of the porous structure due to the incorporation of Al₂O₃ and SiO₂ nanoparticles, which reduce defect density and limit the adhesive–abrasive wear mechanism. Full article

The inevitable pore defects generated in the preparation process have a great impact on the mechanical properties of the ceramic matrix composites. However, the pore defects on the composites were ignored to a large extent in models established in the previous research. In this study, in order to investigate the bending damage behaviors of SiC_f/SiC (SiC fiber-reinforced SiC matrix) angle-interlock (2.5D) woven composites prepared by the precursor immersion pyrolysis (PIP) method, a more precise full-scale model of composites was established by finite element (FE) method with taking into account of random pore defects generated by Monte Carlo algorithm. Micro-computed tomography (Micro-CT) was employed to acquire the statistical data of the yarns and pores of SiC_f/SiC 2.5D woven composites. A bending test was conducted to study the damage behaviors of the composite and compared with the prediction of the FE model. The result shows that the proposed model with random pores can predict the mechanical damage behavior of SiC_f/SiC 2.5D woven composites effectively under three-point bending. The simulated bending strength shows a good agreement with the experimental data, with a relative error of approximately 4.6%. Full article

In metal additive manufacturing, the molten pool directly influences the performance of the fabricated components. Therefore, a comprehensive understanding of the molten pool behavior is essential for improving the quality of the parts and mitigating the formation of defects. Selective arc melting (SAM) is a promising additive manufacturing method for fabricating metal matrix composites. However, the melting and solidification process of the powder layer under the arc heat source remains unrevealed. This study aims to elucidate the formation mechanisms of surface morphology during SAM processing and the influence of carbide addition on the melting and solidification behavior of Inconel 718 powder. In this study, thin-walled parts of Inconel 718 and TiC/Inconel 718 composite were fabricated and their microstructures were studied. The melting and solidification behavior of Inconel 718 and TiC/Inconel 718 composite during single-track single-layer deposition was investigated using high-speed photography. Focusing on the differences in the sidewall surface morphology of the Inconel 718 and TiC/Inconel 718 composite parts, the edge feature formation of the deposition track of both materials was studied. Furthermore, the formation mechanism of the differences in forming height at different positions of the deposition track was explored. The results indicate that the melted material in the molten pool of Inconel 718 mainly comes from the mass transport of the beads generated around the molten pool, while the liquid material in the molten pool of TiC/Inconel 718 composite mainly comes from the in situ powder melted under the arc center. During the melting process of Inconel 718 powder, beads at the edge of the heating area come into contact with the boundary of the molten pool and solidify in situ, forming protrusion features. The randomness in the bead size leads to different volumes of molten material at different positions within the same time, thereby causing variations in building height. Full article

Silicone rubber optical fiber composite insulators introduce interface defects due to embedded optical fibers, and their structural design remains immature, resulting in inadequate interface sealing performance. In actual operation, the combined effects of high electric fields, high humidity and heat, and mechanical loads lead to frequent failures. This study proposes replacing conventional silicone rubber with cycloaliphatic epoxy resin (CEP), which exhibits superior aging resistance, to enhance long-term operational reliability. However, the correlation mechanism between the structural parameters of CEP optical fiber insulators and their electromechanical properties remains unclear, lacking corresponding design basis. Therefore, based on finite element simulation technology, this study systematically analyzed the influence patterns of core rod diameter, fiber implantation method, spiral groove angle, fiber implantation quantity, and voltage equalization ring structural parameters (outer diameter, circular tube radius, shielding depth) on their mechanical and electrical properties. Research findings indicate that in terms of mechanical properties, the helical groove structure with a 40 mm core rod diameter, a groove angle of 135°, and six embedded optical fibers exhibits the lowest optical fiber strain. In terms of electrical performance, the minimum peak electric field strength at the end of the insulator occurs when the equalizing ring has an outer diameter of 370 mm, the circular tube radius is 25 mm, and the shielding depth is 50 mm, reaching only 4.6 kV/cm, which meets the requirements of DL/T 1000.3-2015. This study establishes optimization principles for key structural parameters of CEP optical fiber composite insulators, offering significant engineering value for enhancing the overall performance of optical fiber composite insulators and improving the operational safety of power systems. Full article

Rapid vascularization is essential for bone regeneration in oral and maxillofacial surgery. This systematic review synthesised in vivo evidence on 3D-printed composite scaffolds in rodent critical-size calvarial defects quantified by Microfil perfusion and micro-CT. “Composite” was defined as an organic–inorganic construct within the printed scaffold (not a single-phase scaffold with a surface coating). PubMed, MEDLINE, and Web of Science Core Collection were searched for studies published from January 2014 to December 2025. Eligible studies compared composite scaffolds with non-composite (single-phase) scaffolds and/or empty controls and reported vascular outcomes (vessel number, vascularized area) together with bone outcomes (new bone area, bone volume fraction [BV/TV], and bone mineral density). Ten studies met the inclusion criteria. In outcome-specific exploratory analyses, composite scaffolds were associated with higher new bone area than comparators (p = 0.031). Functional modifications were associated with higher vascularized area (p = 0.025) and higher new bone area (p = 0.038), while dual-factor modifications showed the largest gain in new bone area (p = 0.002). Pore sizes ≥ 400 μm were associated with higher BV/TV (p = 0.029). Heterogeneity in designs, follow-up, and reporting, together with small sample sizes, precluded meta-analysis. Composite scaffolds appear promising, but standardised methodologies and improved reporting are needed to define optimal design features and support translation. Full article