Search Results (583)

The texture of asphalt pavement wears down over time due to traffic polishing, which leads to polished pavement surfaces with lower skid resistance. Three-dimensional (3D) texture parameters can be used to describe the evolution of pavement texture and establish predictive models for skid resistance. In this study, a high-resolution 3D laser scanner and a pendulum friction tester were used to collect 3D texture data and the corresponding friction values of dense-graded asphalt pavement over a period of four years. Fourier transformer and Butterworth filters were applied to decompose the 3D texture data into micro-texture and macro-texture components. Twenty different 3D texture parameters from five categories (height, spatial, hybrid, functional, and feature parameters) were calculated from pavement micro- and macro-textures and optimized using correlation methods to derive an independent set of texture parameters. The performance of a multiple linear regression model and neural network predictive model for predicting skid resistance via selected texture parameters was compared through training and testing. The results indicate that pavement micro-texture contributes more significantly to skid resistance than macro-texture, and neural network models can effectively predict the temporal evolution of skid resistance based on texture data. The neural network model achieves R² values of 0.92 and 0.89 on the training and testing sets, respectively, with RMSE values of 3.37 and 5.45, significantly outperforming the multiple linear regression model (R² = 0.50). Full article

Rutting is a critical form of pavement distress that compromises driving safety and long-term structural integrity. Traditional detection methods predominantly rely on cross-sectional measurements and high-cost inertial navigation-assisted laser scanning, which limits their applicability for large-scale, full-section evaluation. To address these limitations, this study proposes a framework for full-section rutting detection leveraging an area-array structured light camera for efficient 3D data acquisition. A multi-scale texture enhancement strategy based on 2D wavelet transform is introduced to extract latent surface features, enabling robust and accurate point-cloud registration without the need for artificial markers. Additionally, an improved Random Sample Consensus—Density-Based Spatial Clustering of Applications with Noise (RANSAC-DBSCAN) algorithm is designed to enhance the precision and robustness of rutting region segmentation under real-world pavement conditions. The proposed method is experimentally validated using 102 multi-frame pavement point clouds. Compared to Fast Point Feature Histograms (FPFH) and Deep Closest Point (DCP), the registration approach achieves a 71.31% and 80.64% reduction in point-to-plane error, respectively. For rutting segmentation, the enhanced clustering method attains an average F1-score of 90.5%, outperforming baseline methods by over 15%. The proposed workflow can be seamlessly integrated into vehicle-mounted structured-light inspection systems, offering a low-cost and scalable solution for near real-time, full-lane rutting detection in routine pavement monitoring. Full article

Structured CBN (cubic boron nitride) grinding wheels usually have a specially designed texture on their surface to reduce the grinding heat and grinding force. However, most structured grinding wheels are fabricated by electroplating, brazing, sintering, and mechanical or laser removal on the surface of conventional grinding wheels, which may have problems such as complicated processes, low processing efficiency, and unstable effects. In this paper, additive manufacturing was used to fabricate a radial straight groove-structured grinding wheel. Meanwhile, a corresponding mathematical model of the grinding wheel was also established considering the shape and position of the abrasive grains. Subsequently, the ground surface morphologies of the fabricated wheel and simulated wheel under different machining parameter conditions were compared to further prove the rationality of the simulated grinding wheel. The results showed that the ground surfaces of the fabricated wheel and simulated wheel had similar morphological characteristics. The trend in the surface roughness under the different machining parameter conditions was also analyzed and showed the same variation for fabricated and simulated wheels; the error rate was confined within 8%. This paper elucidates the grinding mechanism and surface morphology formation process of a radial straight groove-structured grinding wheel fabricated by additive manufacturing. Full article

In recent years, digital technologies have become indispensable tools for the preservation and documentation of architectural and cultural heritage. Traditional 3D modeling methods, such as photogrammetry and laser scanning, require specialized equipment and extensive manual processing. Neural Radiance Field, an AI-based technique, enables photorealistic 3D reconstructions from a limited set of 2D images. NeRF excels in cultural heritage documentation by effectively rendering reflective and translucent surfaces, which often pose challenges to conventional methods. These approaches significantly accelerate workflows, reduce costs, and minimize manual intervention, making them ideal for inaccessible or fragile sites. The application of NeRF combined with drone-acquired high-resolution images, as demonstrated in the Katolička Porta project in Novi Sad, produces highly detailed and accurate digital replicas. This integration also supports virtual restoration and texture enhancement, enabling non-invasive exploration of conservation scenarios. Katolička Porta, a historically significant site that has evolved over centuries, benefits from these advanced digital preservation techniques, which help maintain its unique architectural and cultural identity. This integration of technologies represents the future of cultural heritage conservation, offering innovative possibilities for visualization, research, and protection. Full article

Surface roughness influences biofilm adhesion on denture base materials, impacting oral health. Despite advances in polymeric denture materials, the effects of common cleaning protocols on their surface texture remain inadequately characterized. This study investigated the influence of toothbrush abrasion on the surface texture of dimethyl methacrylate-based (DMA, printed: V-Print dentbase), polymethyl methacrylate (PMMA, milled: VITA Vionic Base, pressed: IvoBase Hybrid), polyamide (PA, pressed: Bre.flex), and polyether ether ketone (PEEK, milled: Juvora Disc). The specimens were fabricated as polished discs. The Vickers and Martens hardness, indentation modulus, elastic and plastic part of indentation work, and indentation creep were determined. Toothbrushing simulation and surface texture analysis were conducted in three steps: 1800, 1800, and 3600 cycles using water, dish detergent, or toothpaste slurry. The surface texture parameters Sa, Sal, Sdr, Sku, and Ssk were determined using confocal laser scanning microscopy and suitable filtering (S-F and S-L surface). Sa, Sal, and Sdr showed significant changes depending on the choice of medium and the material used. The duration had a small effect (three-way ANOVA; all p < 0.001). DMA showed minor surface changes. Milled and pressed PMMA exhibited similar surface deformities due to wide valleys that were not considered critical for biofilm adhesion. PA showed the lowest and PEEK the highest Vickers and Martens hardness. However, both PA and PEEK exhibited surface changes that could promote biofilm development. These findings suggest that denture cleaning recommendations should remain material-specific. Regular surface inspections and repolishing are necessary to reduce the risk of biofilm formation on PA or PEEK-containing dentures. Full article

The experimental study has been carried out using advanced computer vision methods in order to visualize the moment of excitation and further propagation of a non stationary isotropic domain in a hybrid aligned nematic (HAN) microsized volume under the effect of a laser beam focused on a bounding liquid crystal surface. It has been shown that, when the laser power exceeds a certain threshold value, in bulk of the HAN microvolume, an isotropic circular domain is formed. We also observed a structure of alternating concentric rings around the isotropic circular region, which increases with distance from the center of the isotropic domain. The formation of a sequence of rings in a polarizing microscopic image indicates the formation of a complex topology of the director field in the HAN cell under study. The following evolution of the texture can be represented by two modes. Firstly, the “fast” heating mode, which is responsible for the formation and explosive expansion of an isotropic zone in bulk of the HAN microvolume with characteristic time ${\tau }_1$ due to a laser spot heating on the upper indium tin oxide (ITO) layer. Secondly, the “slow” heating mode, when an isotropic zone and concentric rings slowly expand with characteristic time ${\tau }_2$ mainly due to the finite thermoconductivity of ITO layer. When the laser power significantly exceeds the threshold value, damped oscillations of the isotropic domain are observed. We also introduced the metrics that allows quantitatively estimate the behavior of texture observed. The results obtained form an experimental basis for further investigation of thermomechanical force appearing in the LC system with coupled gradients of temperature and director fields. Full article

To reduce the friction coefficient and wear in tillage machinery during operation, biomimetic textures with different densities inspired by the short-tailed shrew’s claw were designed using biomimetic principles. These textures were applied to the surface of 65Mn steel using laser processing technology. This study investigated the effects of these bionic textures on the tribological properties of 65Mn steel surfaces in two environments: dry friction and soil friction. Friction and wear tests were conducted, and the friction coefficient, wear morphology, and wear quality were measured using a friction and wear testing machine, a scanning electron microscope (SEM), and a three-dimensional profilometer. The results indicate that under dry friction conditions, the tribological properties of specimens with bionic textures were significantly improved compared to non-textured specimens. The frictional properties of the specimens with bionic textures were optimized at a texture density of 20%, with an average coefficient of friction reduction of 24%. Under soil friction conditions, the samples with bionic textures demonstrated better tribological performance at densities of 20% and 30% compared to the non-textured samples, with decreases in the average coefficient of friction of 1.3% and 2.9%. The special surface structure of the bionic short-tailed shrew claw can effectively reduce friction heat effects and wear, demonstrating significant anti-friction and anti-wear performance. Full article

Excessive surface friction encountered during metal-forming processes typically leads to die wear and seizure in part surfaces, which consequently shortens the die’s service lifespan and lowers the surface quality of the formed parts. To minimize surface friction, tool surface modification is required. This study focuses on reducing the sliding friction of SKH51 high-speed steel by fabricating micro-grooves with various crosshatch angles using a nanosecond pulse laser. The effects of laser texturing parameters on achieving the groove aspect ratio of 0.1 were investigated. This aspect ratio facilitates lubricant retention and enhances lubrication performance on the contact surfaces. The influence of groove crosshatch angles (30°, 60°, and 90°) on the friction in the sliding contact between a textured high-speed steel disc and an AISI304 stainless steel pin was evaluated using a pin-on-disc test with a constant load. Moreover, the contact pressure distribution and stress concentration associated with each groove pattern were numerically analyzed using the finite element method. The results demonstrated that a laser power of 20 W effectively produced groove geometries with the desired aspect ratio. Among the tested patterns, the surface textured with a 60° crosshatch angle exhibited the lowest coefficient of friction of 0.111, compared to 0.148 for the untextured surface. Finite element analysis further revealed that the 60° crosshatch pattern provided the most balanced combination of load redistribution, reduced mean pressure, and average stress, which may reduce the friction under sliding conditions. These findings confirm that laser surface texturing, particularly with an optimized crosshatch angle, can significantly reduce sliding friction and enhance the tribological performance of high-speed steel tools. Full article

Preventive maintenance treatments are widely applied to asphalt pavements to mitigate deterioration and extend service life. This study evaluated four common technologies: a high-elasticity ultra-thin overlay, an Stone Mastic Asphalt (SMA)-10 thin overlay, micro-surfacing (MS-III), and a chip seal. Laboratory testing focused on skid resistance, surface texture, and low-temperature cracking resistance. Skid resistance was measured with a tire–pavement dynamic friction analyzer under controlled load and speed, while surface macrotexture was assessed using a laser scanner. Low-temperature cracking resistance was determined through three-point bending beam tests at −10 °C. The results showed that chip seal achieved the highest initial friction and texture depth, immediately enhancing skid resistance but exhibiting rapid texture loss and gradual friction decay. Micro-surfacing also demonstrated good initial skid resistance but experienced a sharp reduction of over 30% due to fine aggregate polishing. By contrast, the high-elastic ultra-thin overlay and SMA thin overlay provided more stable skid resistance, lower long-term friction loss, and excellent crack resistance. The polymer-modified ultra-thin overlay achieved the highest low-temperature bending strain ≈40% higher than untreated pavement, indicating superior crack resistance, followed by the SMA thin overlay. Micro-surfacing with a chip seal layer only slightly improved low-temperature performance. Overall, the high-elastic ultra-thin overlay proved to be the most balanced preventive maintenance option under heavy-load traffic and cold climate conditions, combining durable skid resistance with enhanced crack resistance. Full article

Superhydrophobic surfaces, characterized by water contact angles greater than 150°, have attracted widespread interest due to their exceptional water repellency and multifunctional applications. However, traditional fabrication methods often rely on fluorinated compounds and petroleum-based polymers, raising environmental and health concerns. In response to growing environmental and health problems, recent research has increasingly focused on developing green superhydrophobic surfaces, employing eco-friendly materials, energy-efficient processes, and non-toxic modifiers. This review systematically summarizes recent progress in the development of green superhydrophobic materials, focusing on the use of natural substrates such as cellulose, chitosan, starch, lignin, and silk fibroin. Sustainable fabrication techniques, including spray coating, dip coating, sol–gel processing, electrospinning, laser texturing, and self-assembly, are critically discussed with regards to their environmental compatibility, scalability, and integration with biodegradable components. Furthermore, the functional performance of these coatings is explored in diverse application fields, including self-cleaning, oil–water separation, anti-corrosion, anti-icing, food packaging, and biomedical devices. Key challenges such as mechanical durability, substrate adhesion, and large-scale processing are addressed, alongside emerging strategies that combine green chemistry with surface engineering. This review provides a comprehensive perspective on the design and deployment of eco-friendly superhydrophobic surfaces, aiming to accelerate their practical implementation across sustainable technologies. Full article

This study investigates the microstructural and mechanical evolution of Ti6Al4V alloy surfaces modified through laser surface alloying (LSA) with antimicrobial elements silver (Ag) and copper (Cu) to enhance surface performance for biomedical applications. The as-received Ti6Al4V exhibited a typical equiaxed $\alpha \text{-}\beta$ microstructure with baseline hardness. Following LSA treatment using a 1000 W pulsed laser, distinct transformations were observed in the melt zone (MZ) and heat-affected zone (HAZ), influenced by the specific alloying element. Ag incorporation led to the development of ultrafine acicular martensitic structures and a higher fraction of high-angle grain boundaries, resulting in moderate hardness improvement. In contrast, Cu alloying promoted the formation of Ti₂Cu intermetallic phases, dendritic morphologies, and pronounced solute segregation, leading to a more significant increase in hardness. Electron Backscatter Diffraction(EBSD) and Energy Dispersive Spectroscopy (EDS) analyses revealed grain refinement, texture evolution, and elemental redistribution across the modified regions, while X-ray Diffraction XRD confirmed the presence of new phases. The comparative analysis highlights that although both Ag and Cu improve microstructural complexity and hardness, Cu-modified zones exhibited higher hardness values than Ag-modified zones, suggesting a stronger surface strengthening effect under the tested conditions. These findings contribute valuable insights into the structure–property relationships of LSA-modified Ti alloys, supporting their potential for durable and antimicrobial biomedical implants. Full article

Surface roughness and morphology, along with surface chemistry, are key features for improving ingrowth behavior and combating peri-implantitis after the insertion of dental implants. Using femtosecond laser texturing, this study aims to control both morphological and topographical surface properties of a glass solder coating on a zirconia substrate for dental applications. Experiments with varying laser and scanning parameters on the upper glass solder layer show the occurrence of two different surface morphologies. On the one hand, periodic wave-like structures are generated at relatively low pulse energy, with a high scanning pulse overlap of 80 to 90% and a scanning line overlap of 50%. On the other hand, a cauliflower-like structure can be observed at high pulse energies and a line overlap of up to 90%. Both surface morphologies represent a potential way to modify the glass solder surface to customize hard- and soft-tissue ingrowth, while realizing anti-adhesive properties for pathogenic bacteria in dental applications. Full article

The reduced ductility caused by the brittle needle-like α′ martensite limits the application of TC4 alloys produced by selective laser melting (SLM). Appropriate heat treatment can improve the microstructures and properties of SLM-fabricated TC4 alloys. In this work, SLM-fabricated TC4 alloys underwent stress relief annealing at 600 °C and high-temperature annealing at 800 °C. The effects of heat treatment temperature on phase composition, microstructural morphology, grain orientation, and mechanical properties were investigated. Meanwhile, the microstructural evolution and fracture mechanisms during the heat treatment process were analyzed. The results indicate that after annealing at 600 °C, the needle-like α′ phase transforms into elongated α, and nano-β phase increases. When annealed at 800 °C, the α′ phase completely transforms into a more stable lath-shaped α phase and a short rod-shaped β phase, with the nano-β phase disappearing. The texture orientation gradually shifts from <0001> towards <01-10>, where slip systems are more active. Additionally, heat treatment promotes the transition of grain boundaries to high-angle grain boundaries, thereby alleviating stress concentration and enhancing solid-solution strengthening. After heat treatment, the ultimate tensile strength of the material slightly decreases, but the elongation significantly increases. As the annealing temperature increased, the elongation (EL) improved from 5.22% to 11.43%. Following high-temperature annealing at 800 °C, necking and larger dimples appear on the fracture surface, and the fracture mechanism shifts from a mixed brittle–ductile fracture to a ductile fracture. This work provides a theoretical basis for improving the microstructures and properties of SLM-fabricated TC4 alloys through heat treatment. Full article

The anti-slip performance of road surfaces directly affects traffic safety, yet existing evaluation methods based on texture features often suffer from limited interpretability and low accuracy. To overcome these limitations, a portable 3D laser surface analyzer was used to acquire road texture data, while a dynamic friction coefficient tester provided friction measurements. A multi-view fractal dimension index was developed to comprehensively describe the complexity of texture across spatial, cross-sectional, and depth dimensions. Combined with road surface temperature, this index was integrated into an XGBoost-based prediction model to evaluate friction at driving speeds of 10 km/h and 70 km/h. Comparative analysis with linear regression, decision tree, support vector machine, random forest, and backpropagation (BP) neural network models confirmed the superior predictive performance of the proposed approach. The model achieved backpropagation (R²) values of 0.80 and 0.82, with root mean square errors (RMSEs) of 0.05 and 0.04, respectively. Feature importance analysis indicated that fractal characteristics from multiple texture perspectives, together with temperature, significantly influence anti-slip performance. The results demonstrate the feasibility of using non-contact texture-based methods to replace traditional contact-based friction testing. Compared with traditional statistical indices and alternative machine learning algorithms, the proposed model achieved improvements in R² (up to 0.82) and reduced RMSE (as low as 0.04). This study provides a robust indicator system and predictive model to advance road surface safety assessment technologies. Full article

Surface texturing involves creating micro-channels, micro-dimples, micro-grooving, and other surface modifications. To do this, laser and micromachining are employed on the substrate surface in addition to other methods. The surface characteristics of the Arboblend V2 Nature biodegradable polymers with laser texturing, hexagonal and square patterns, and four and six passes are shown in this study. Regardless of the texture type, Arboblend V2 Nature’s hydrophilic surface (a contact angle of less than 90°) was demonstrated by the results of the wettability test. The underlying material’s wear behavior changed as a result of the LST surface modification. The COF values increased only after six passes with both textures. On the topographical side, Arboblend V2 Nature (square and hexagonal) shows a consistent X-axis expansion in the hexagonal geometry and a considerable amount of variability in the square geometry, especially at six passes, where the Y-axis (higher depths) is more compressed. According to the results, since textured surfaces are practicable, non-biodegradable polymers from a variety of industries can be substituted. Full article