Search Results (752)

This paper comprehensively investigates the ultraviolet (UV) nanosecond laser fabrication of micro-groove textures on planar PEEK surfaces, as well as their surface performance in terms of wettability and frictional properties. Firstly, a three-dimensional finite element model, incorporating a moving Gaussian heat source, solid heat transfer and deformed geometry, was established to simulate the transient temperature field and ablation profile of PEEK during UV laser ablation. The predicted groove depth agreed with the experimental value with a low deviation of 11.19%. Based on the simulation and single-factor experiments, the optimized single-track laser parameters were determined as a laser power of 1.2 W, a scanning speed of 100 mm/s and a repetitive frequency of 100 kHz. Secondly, systematic single-factor and multi-pass laser ablation experiments of PEEK surfaces were conducted to fabricate micro-groove textures with precisely tailored geometric parameters. Furthermore, ablated surface characterization showed that the laser-textured surfaces exhibited increased roughness, apparent crystallinity up to 22.13%, and pronounced anisotropic wettability, with improved liquid spreading along the groove direction and restricted spreading across the grooves. Finally, fretting wear tests under simulated body fluid lubrication were carried out. The research findings reported in this paper provide a systematic theoretical and experimental basis for the application of UV nanosecond laser surface texturing in the fabrication of PEEK-based components. Full article

The present study aimed to optimize the fabrication conditions of walnut oil–fructooligosaccharide emulsion and evaluate its efficacy in improving the quality of cooked rice. Three food-grade emulsifiers, namely sucrose fatty acid ester (SE), polyglycerol fatty acid esters (PGEs), and diacetyl tartaric acid ester of mono- and diglycerides (DATEM), were adopted to investigate the influences of water–oil ratio, emulsifier dosage, and high-pressure microfluidization (HPM) pressure on emulsion indicators including the emulsion stability index (ESI), particle size, polydispersity index (PDI), zeta potential, micromorphology, and storage stability. The results reveal that SE exhibited the superior emulsifying capacity, with the optimal water–oil ratio and SE dosage determined to be 6:4 and 4% (w/w, based on oil mass), respectively. HPM treatment further reduced droplet size and elevated the ESI, and 150 MPa was identified as the optimal homogenization pressure. Subsequently, the optimized emulsion was applied during rice cooking, with water, pure walnut oil, pure fructooligosaccharide (FOS), simple physical mixture of the two raw materials and crude emulsion set as parallel control groups. Compared with all control treatments, rice cooked with 150 MPa homogenized emulsion possessed the minimum hardness value of 3297.22 and the maximum springiness of 0.74, accompanied by the optimal water retention capacity, luminosity, and the most abundant volatile organic compounds (VOCs). In conclusion, walnut oil–fructooligosaccharide emulsion fabricated via HPM exerted synergistic improvements on the texture and flavor of cooked rice, which could provide a technical reference for the functional modification of staple foods. Full article

Cholesteric liquid crystals (CLCs) possess the unique ability to selectively reflect incident circularly polarized light, exhibiting tremendous potential in diverse optical applications. In this study, a trilayer composite architecture of polymer-stabilized cholesteric liquid crystals (PSCLCs) was successfully fabricated. Introducing poly(vinyl alcohol) (PVA) as intervening barrier layers enabled the formation of independent and mutually non-interfering broadband reflection bands within each respective layer. Initially, a single-layer system was evaluated to identify the effects of component concentrations and polymerization conditions on the reflection bandwidth. Under optimal conditions, a maximum reflection bandwidth of 890 nm was achieved. Building upon these parameters, the effective concatenation of two independent reflection bands was accomplished by precisely regulating the concentration of the chiral dopant R5011 in the adjacent layers. Subsequently, the trilayer PSCLC film was constructed, ultimately broadening the total reflection bandwidth to 1650 nm. Characterization via polarized optical microscopy (POM) confirmed that the liquid crystal molecules consistently maintained a well-defined planar texture throughout the fabrication process of the multilayer films. Additionally, the film shows good infrared shielding performance. Its ability to regulate ambient light makes it highly promising as an optical filter and thermal management component in LC smart windows and emerging displays. Full article

To improve the antifouling and self-cleaning performance of 3003 aluminum alloy, a fluorine-free water-repellent surface was fabricated by combining nanosecond laser texturing with subsequent heat treatment. The effects of scanning speed, laser power, pulse frequency, and scanning interval on surface wettability were systematically investigated. Under the optimal conditions of 2700 mm/s, 6 W, 35 kHz, and 20 μm, the surface achieved a maximum static water contact angle of 154.3 ± 0.8°. Surface characterization showed that laser processing generated hierarchical micro-/nano-scale structures, while heat treatment promoted surface chemical evolution associated with enhanced hydrophobicity. The highly water-repellent behavior resulted from the synergistic effect of hierarchical roughness and heat-treatment-induced surface chemical changes. The fabricated surface exhibited effective self-cleaning performance, achieving a SiO₂ removal efficiency of 98.8% under the specified test conditions. In addition, relatively high water repellency was retained after repeated water-impact and tape-peeling tests. These results demonstrate that nanosecond laser texturing combined with heat treatment provides a simple and environmentally friendly strategy for fabricating water-repellent AA3003 surfaces for antifouling and surface-protection applications. Full article

Biomimetic surface texturing provides a promising strategy for regulating the vibration behavior of rolling bearings under starved lubrication. In this study, vein-like, elliptical, semi-elliptical, and composite textures inspired by Monstera deliciosa leaves were fabricated on the shaft-washer raceways of thrust cylindrical roller bearings at depths of 4 μm, 8 μm, and 12 μm. Tangential and normal vibration signals were analyzed using time-domain parameters, frequency spectra, power spectral density, and time–frequency maps. The results showed that both texture morphology and depth strongly affected vibration stability. Most textured bearings exhibited lower vibration responses than the smooth bearing after prolonged operation. Among the tested depths, 8 μm produced the most stable response, characterized by lower peak values, smoother root mean square curves, reduced power spectral density levels, and more uniform time–frequency energy distributions. The 8 μm semi-elliptical texture exhibited the best overall performance by suppressing transient impacts and high-frequency energy concentration. These findings indicate that vibration regulation in textured rolling bearings depends primarily on the synergistic matching between texture morphology and depth rather than texture complexity alone. Full article

Driven by energy conservation, emission reduction and lightweight manufacturing demands, wrought magnesium alloys feature low density, high specific strength and balanced comprehensive performances, making them promising lightweight materials for aerospace, automobile, electronic and other industries. This paper systematically reviews the rolling fabrication technologies and recent research progress of wrought magnesium alloy sheets. Special attention is paid to deformation characteristics, microstructure evolution mechanisms and property regulation rules of typical rolling processes, including conventional rolling, cross rolling, accumulative roll bonding, equal-channel angular rolling, asymmetric rolling and twin-roll casting. Existing studies confirm that dynamic recrystallization, grain refinement, activation of non-basal slips and basal texture weakening act as core mechanisms to enhance the strength–ductility matching, formability and anisotropy of magnesium alloy sheets. Each rolling technology possesses unique merits in production efficiency, microstructural homogeneity, texture modification and industrial practicability. Nevertheless, several bottlenecks still restrict its large-scale promotion, such as edge cracking, strong basal texture, poor process stability and high manufacturing cost. Future research priorities lie in multi-process compound forming, intelligent parameter control and short-process eco-friendly manufacturing, so as to facilitate mass production and extensive engineering application of high-performance wrought magnesium alloy sheets. Full article

Laser powder bed fusion (LPBF)-fabricated TA15 titanium alloy commonly exhibits a fine acicular lath morphology, which has frequently been interpreted as martensitic in previous studies and is generally associated with high strength and limited plastic accommodation. In this study, LPBF-TA15 specimens were annealed at 800, 900, and 950 °C for 2 h, followed by furnace cooling, and subsequently subjected to secondary annealing at 550 °C for 4 h. Each sequentially annealed condition was compared with its corresponding single-step condition to distinguish retained microstructural differences from the tensile-property changes associated with the subsequent treatment. Microstructural evolution and monotonic tensile properties at room temperature and 300–600 °C were investigated. Annealing at 800 °C retained a relatively fine lamellar morphology. Increasing the initial annealing temperature to 900 and 950 °C produced progressively larger apparent lath and colony scales, with the most pronounced coarsening observed at 950 °C. Tensile results are reported as mean ± standard deviation. After secondary annealing, A800-S550 exhibited the highest mean room-temperature strength among the three secondary-annealed conditions, with a yield strength of 1045.0 ± 2.6 MPa, an ultimate tensile strength of 1116.7 ± 2.3 MPa, and an elongation of 14.3 ± 0.7%. From 300 to 600 °C, its yield strength decreased from 701.0 ± 3.2 to 493.6 ± 9.8 MPa, while its ultimate tensile strength decreased from 823.5 ± 3.8 to 585.6 ± 7.1 MPa; the elongation at 600 °C was 19.0 ± 1.8%. In this study, microstructural inheritance refers to the persistence, after the common 550 °C treatment, of differences in lath and lamellar-colony scales and EBSD boundary characteristics established during initial annealing. The secondary-annealed conditions retained distinct microstructural scales and exhibited different tensile responses; however, a unique causal relationship between the retained morphology and the magnitude of the property changes was not established. Residual stress, post-heat-treatment oxygen variation, and quantitative texture evolution were not independently evaluated. The conclusions are limited to the heat-treatment schedules and monotonic tensile conditions examined in this study. Full article

Automated cotton-percentage identification underpins sustainable textile recycling, but established near-infrared and ATR-FTIR spectroscopy systems cost USD 10,000–25,000 per unit and remain inaccessible to small recyclers. We address this on the CottonFabricImageBD dataset (1300 RGB originals, 13 ordinal cotton classes from 30% to 99%) and report three contributions. First, the Learnable Residual LBP stem, which retains the pretrained ResNet50 first convolution intact and adds a fully differentiable Local Binary Pattern branch as an additive contribution gated by a single learnable scalar $\alpha$ initialized to zero, ensuring the model is numerically equivalent to the baseline at initialization (verified to a maximum absolute logit difference below ${10}^{-4}$). Second, a controlled six-variant comparison (vanilla baseline, CLBP, LBP-Conv, LBP-Residual, LBP+SVM, LBP+ANN) under identical stratified five-fold cross-validation on the 1300 dataset originals. Third, the isolation of pretraining preservation as the dominant architectural variable: the 7.08 pp top-1 gap between LBP-Conv (43.77%) and LBP-Residual (50.85%), both embedding the identical learnable LBP module, is statistically significant ($p=0.004$, uncorrected paired t-test, $df=4$) and consistent across all five folds. This gap mainly reconfirms, in the LBP setting, the established cost of discarding pretrained early-layer filters; by contrast, the improvement of LBP-Residual over the vanilla baseline (1.31 pp top-1) is consistent in direction but not statistically significant at the five-fold level ($p=0.229$), so LBP-Residual, CLBP (50.23% top-1), and the baseline (49.54% top-1) are statistically tied on aggregate accuracy and the ranking among them is exploratory. Classical LBP+SVM and LBP+ANN baselines reach 31.85% and 34.46% top-1, confirming a genuine but limited cotton-density signal in hand-crafted descriptors. Compared to the concurrent triplet-architecture approach of Wiedemann et al. (2025), which achieves 48.15% top-1 accuracy on the same dataset under identical five-fold cross-validation, LBP-Residual attains 50.85% top-1 using a single lightweight backbone rather than an ensemble of three. These results support the design principle: augment, do not replace. Full article

Solid solution with molybdenum is an effective strategy for improving the overall performance of tungsten alloys, thereby enhancing their application potential in aerospace and other fields. In this study, highly dense W-Mo alloy specimens were successfully fabricated using laser powder bed fusion, followed by stress-relief annealing. The results show that the complete solid solution of molybdenum yields a fine columnar grain structure with weak texture. After stress-relief annealing, the residual stress decreases, the grain size increases slightly, and the fraction of the <111>//building direction (BD) texture rises. Ultimately, W-Mo alloy specimens with excellent compressive properties are obtained, with compressive yield strength, ultimate compressive strength, and compressive strain reaching 879.5 MPa, 1257.3 MPa, and 16.6%, respectively. This work provides new insights into the fabrication of refractory alloys by laser powder bed fusion. Full article

Thin sections are fundamental tools in mineralogy, petrography, archaeometry, paleontology, and heritage science, allowing for the microscopic study of mineral assemblages, rock textures, ceramic fabrics, and fossil microstructures. Although thin-section preparation is often presented as a standardized technical procedure, the quality and interpretative reliability of the final section depend strongly on material behavior, laboratory equipment, bonding and thinning procedures, thickness-control criteria, and operator decisions made during preparation. This paper examines thin-section preparation as a process of methodological calibration, understood as the material-specific adjustment of preparation decisions in order to preserve the microstructural features required for subsequent interpretation. The study combines an overview of current preparation practice with documented hands-on workflows from academic and heritage-oriented thin-section laboratories. Two case studies are used to develop the calibration framework. The first concerns silicified fossil wood and marly carbonate samples prepared at the Department of Geology, University of Patras, Greece, using water-cooled cutting, epoxy bonding under heat and pressure, machine-assisted and manual thinning, micrometer-based thickness monitoring, and optical assessment adapted to carbonate-rich samples. The second concerns archaeological ceramics, fossiliferous limestone, oolitic limestone, and coherent lithic/sedimentary samples prepared at the INSTAP Study Center for East Crete, Greece, where preparation decisions included mounting-face selection, cleaning, vacuum impregnation where required, controlled lapping, and transmitted/polarized-light quality assessment. Together, the case studies show that equivalent preparation stages require different operational decisions according to hardness, brittleness, porosity, cohesion, fossil content, ceramic fabric, and intended analytical purpose. Preparation-induced features such as microcracks, smearing, surface relief, detachment, or loss of weak fabrics may be misread as primary geological, technological, taphonomic, or conservation-related features if preparation choices are not properly considered. Framed in this way, thin-section preparation is positioned as a foundational first step in heritage material characterization, on which the reliability of subsequent optical, electron-optical, and microanalytical methods directly depends. Full article

Additive manufacturing [AM; three-dimensional (3D) printing] is reshaping heterogeneous photocatalysis by enabling architected materials and devices that span from centimeter-scale monoliths to micro- and lab-on-chip reactors. Heterogeneous photocatalysts have traditionally been deployed as powders or simple coatings, which offer high activity but suffer from mass-transfer limitations, poor light utilization and difficult recovery. Three-dimensional (3D) printing now allows precise control over macroscopic geometry, internal channel networks and micro-/nano-scale surface texturing, creating structured photocatalysts and microreactors that can be tailored for specific photon and flow fields. In contrast to recent reviews that primarily survey materials development or additive-manufacturing routes, this work focuses on photocatalytic microreactors and lab-on-chip devices as multi-scale reactors in which catalyst composition, architected geometry, photon management and hydrodynamics are co-designed across length scales. We summarize three-dimensional 3D-printed photocatalytic systems based on polymer–oxide composites, ceramic scaffolds such as zinc oxide (ZnO)/titanium dioxide (TiO₂) clay monoliths, and laser-written titanium dioxide (TiO₂) nano-architectures, with particular emphasis on microfluidic and lab-on-chip implementations fabricated by fused deposition modeling (FDM), direct ink writing (DIW), stereolithography (SLA), digital light processing (DLP) and laser direct writing (LDW). Based on the literature data and representative case studies, we examine how architected lattices, sponges and microreactor chips affect key performance metrics—apparent rate constants, apparent quantum yield (AQY) and space–time yield (STY)—for the degradation of dyes, antibiotics, detergents and other emerging contaminants in realistic matrices, and we compile reported values to illustrate emerging performance trends and limitations. Representative case studies highlight 3D-printed manganese-doped zinc oxide (Mn:ZnO)-decorated sponges used as modular cartridges for greywater and detergent treatment, as well as laser-written titanium dioxide (TiO₂) nano-photocatalysts integrated into microchannels to couple structured light fields with controlled residence times. Finally, we outline materials and process challenges—including ultraviolet (UV) aging of polymer supports, the energy intensity of ceramic sintering and the lack of standardized testing protocols—and identify future research directions formulti-scalee modeling and techno-economic evaluation of three-dimensional (3D)-printed photocatalytic microreactors and devices. Full article

Surface-dominated failures such as micropitting, scuffing, and rolling contact fatigue remain critical challenges for 20CrMnTi gear steel under high-stress and poor lubrication conditions. Inspired by the composite bionic “checkerboard + dot-matrix dimple” architecture found in natural surfaces, this study aims to develop an optimized biomimetic texture combined with a graphene solid lubricant coating to enhance the tribological performance of 20CrMnTi alloy. Laser surface texturing was employed to fabricate the bionic pattern on 20CrMnTi substrates, followed by deposition of an oxysilane-graphene coating. Reciprocating ball-on-disc tribological tests were conducted under both dry friction and oil-lubricated conditions. The results showed that under dry friction, the optimized textured and coated specimen achieved an average friction coefficient of ~0.18, representing a ~62% reduction compared to the untextured surface (~0.47). Under oil lubrication, the friction coefficient was further reduced to ~0.10–0.11, demonstrating a synergistic effect among the texture, graphene coating, and lubricant. Wear volume decreased by over 70% under dry conditions. The dominant wear mechanism shifted from severe adhesive–abrasive–oxidative wear to mild adhesive and abrasive wear. These findings suggest that the proposed composite bionic texture combined with a graphene coating offers an effective strategy for improving the tribological durability of 20CrMnTi gear. Full article

Antimicrobial resistance is a critical global challenge that necessitates the development of durable, material-based strategies to limit pathogen survival and transmission. Conventional cleaning and disinfection methods only provide transient protection due to rapid surface re-contamination. This study investigates the fabrication of polyethylene terephthalate (PET) surfaces designed for antibacterial applications via femtosecond laser-induced micro- and nanostructuring. Surface texturing was performed using a Ti:sapphire femtosecond laser (wavelength λ = 800 nm, pulse duration τ = 70 fs) at peak laser fluences (F) of 2.04 J/cm² and 4.08 J/cm², generating hierarchical surface textures with controlled morphology, spacing, and geometry through ultrafast, non-contact laser processing while preserving the bulk properties of PET. The resulting patterns, including parallel and intersecting microchannels decorated with laser-induced nanostructures, enabled tunable surface roughness and wettability, with water contact angles ranging from 33.21° to 118.2°. Comprehensive surface characterization, including morphological, topographical, and wettability analyses, was performed to establish structure–property relationships associated with previously reported antibacterial surface design principles. However, direct antibacterial performance was not evaluated in the present study and will be the subject of future investigations. In addition, the durability of the laser-structured PET was evaluated under simulated real-life conditions, including thermal cycling, ultraviolet exposure, abrasion, chemical resistance, and dust contamination. The structured surfaces demonstrated high structural and functional stability following environmental testing. The results indicate that the laser-induced surface modifications remain stable under conditions representative of prolonged practical use, supporting their potential long-term applicability for antibacterial and self-cleaning PET surfaces. Full article

Coplanar capacitance detection exhibits remarkable advantages in the detection of road texture in asphalt layers, including high sensitivity and minimal environmental constraints. However, the inherent performance contradiction between signal strength and penetration depth of traditional interdigitated coplanar capacitance sensors (ICCSs) has restricted their widespread application in road texture detection. To address this issue, a hybrid approach combining response surface methodology (RSM) and non-dominated sorting genetic algorithm II (NSGA-II) is developed to optimize the structural parameters that influence the signal strength and penetration depth of a novel ICCS. Initially, a central-composite design (CCD) based on RSM is employed to establish statistical models for the two key sensing performances of ICCSs, namely signal strength and penetration depth. Subsequently, Analysis of Variance (ANOVA) and three-dimensional (3D) response surface plots are utilized to investigate the significant effects of various structural parameters (electrode length, width, and inter-finger gap) on the two sensing performances. Furthermore, NSGA-II is applied to search for global optimal solutions using the established statistical models, thereby achieving multi-performance optimization of the ICCS. Finally, the fabricated ICCS is used to detect the surface texture of asphalt mixture specimens with different gradations, and the results are compared with those obtained by laser point cloud detection. The results indicate that both statistical models are highly significant, with the coefficient of determination (R-squared) exceeding 0.95. All individual structural parameters have a significant impact on the two sensing performances. Based on the optimization by the RSM-NSGA-II hybrid method, the predicted optimal parameters are verified, showing a relative error of less than 5% from the simulation results. Additionally, the detection results of the ICCS are consistent with the laser point-cloud data, demonstrating its feasibility for pavement texture detection. Full article

Material Extrusion (MEX) additive manufacturing (AM) of ABS polymer components often requires post-process machining to achieve the necessary dimensional precision and surface quality. However, the influence of printing parameters and tool–material interaction in hybrid manufacturing remains insufficiently explored. This study investigates the impact of initial hole size (D_start), build orientation, and cutting parameters (cutting speed and feed rate) on the dimensional accuracy and surface roughness of machined holes in ABS-M30 specimens. Samples were fabricated in vertical and horizontal orientations and subjected to drilling in solid material and enlargement of printed pilot holes using a twist drill on a 5-axis machining center. Dimensional deviation and surface roughness (Ra, Rz) were evaluated using coordinate metrology and profilometry. The results showed that the smallest machining allowance (0.062 mm per side) was insufficient to completely remove the printing-induced surface texture, resulting in significantly higher and more variable Ra and Rz values. This distinct low-machining-allowance regime was confirmed by statistical analysis and representative optical observations. Conversely, a machining allowance of 0.565 mm per side (corresponding to D_start = 9 mm) resulted in substantially lower surface roughness (Ra ≈ 1.6 µm). Vertical build orientation generally provided better surface quality than the horizontal orientation, which was consistent with fewer visible surface features in the selected optical fields of view. All machining conditions resulted in negative dimensional deviations, indicating elastic recovery of the ABS material after machining. An exploratory multi-response ranking showed that the lowest composite quality scores for overall final hole quality were associated with D_start = 10 mm (machining allowance of 0.062 mm per side). When the analysis was limited to the machining-dominated regime, the lowest score was obtained for the vertical build orientation, D_start = 9 mm, a cutting speed of 40 m/min, and a feed rate of 0.2 mm/rev. These findings provide preliminary guidelines for selecting hybrid manufacturing conditions for MEX-manufactured ABS-M30 components. Full article