Abstract Floating ring bearings (FRBs) are widely employed in high-speed locomotive turbochargers to address rotor-bearing instabilities that arise under extreme rotational speeds, whereas conventional fluid-film bearings encounter challenges due to non-linear behaviour and instability. The surface texturing with various patterns has been explored for conventional bearing performance improvement, while its application to FRBs remains limited. This study numerically investigates the performance of a bio-inspired herringbone-textured floating ring bearing (HTFRB) in terms of static, dynamic, and stability characteristics. The static performance parameters (load-carrying capacity, power loss, side leakage, and coefficient of friction) of HTFRB are evaluated by solving the Reynolds equation for inner and outer layers using the FDM with successive over-relaxation algorithm. Dynamic coefficients (stiffness and damping) are obtained through the solution of perturbed Reynolds equations. The resulting dynamic coefficients are used to assess the stability parameters, namely equivalent stiffness coefficient, whirl frequency ratio, and critical mass of the rotor. The parametric analysis studies the effect of key herringbone texture parameters (helix angle, groove depth, groove width ratio, and the number of grooves) on bearing performance. The results reveal that bio-inspired HTFRB exhibits superior performance across different geometrical configurations and rotor speeds. The stability analysis confirms the robustness of rotor-HTFRB system, with positive equivalent stiffness coefficients, negative whirl frequency ratios, and a critical mass of rotor significantly exceeding its actual mass, even under varying speeds and dynamic conditions.

Pavement maintenance programs rely on timely and accurate crack assessment to preserve roadway quality and reduce long-term rehabilitation costs. Manual inspection remains the prevailing practice, yet it is slow, subjective, and exposes crews to safety risks. Automating crack detection under real-world roadway conditions remains challenging due to inconsistent lighting, shadows, stains, and surface textures that obscure distress features. This study examines the applicability of an integrated, vehicle-mounted framework for automated pavement crack segmentation and width-based severity estimation under practical roadway operating conditions. Data were collected from a moving vehicle using a custom camera–GPS system operating under diverse conditions, capturing the variability encountered in practical surveys. The proposed approach employs a state-of-the-art segmentation model and a calibrated width estimation tool that converts pixel-level crack measurements into physical units using a position-dependent regression model. The key contribution of this work is a unified segmentation and severity evaluation pipeline supported by a novel pixel-to-inch calibration surface and validated using images acquired during normal driving operations and manual field crack measurements. By combining advanced computer vision techniques with practical field-oriented data collection, the proposed system provides a deployable solution for roadway crack assessment, enabling safer, faster, and more scalable network-level pavement monitoring.

Dental implantation is the most reliable method for replacing missing teeth. Success rate of dental implants is influenced by osseointegration. Surface roughness of implants influences osseointegration by altering surface area and texture, providing stimulation to cells. Sandblasting and acid-etching are common methods for making implant surfaces rough. Main goal of this study was to investigate effects of sandblasting and acid-etching variables, that is, blasting-pressure and acid-temperature, on surface roughness of implants to find the controlled values of variables for a favorable surface roughness. An acceptable surface roughness was assumed to have an arithmetic average height (Sa) between 1 and 2 µm, and an area developed ratio (Sdr) over 50%. Seventy-two titanium-made analogs were sandblasted with three different pressures, that is, 4, 5, and 6 MPa, and three different durations, that is, 15, 30, and 45 s, and then were etched with two different etching temperature, that is, 60°C and 80°C, and two exposure-time, that is, 5 and 10 min (two repetition for each combination). Surface roughness parameters were then measured using a profilometer. Multi-factorial ANOVA was used as statistical analysis method. Results showed that 14 groups demonstrated favorable Sa (1-2 µm), among which just four groups had acceptable Sdr (Sdr > 50%). Among four parameters stated above, which affect sandblasting and acid-etching processes, it was found that blasting duration is the most effective variable on implants roughness. This work highlights the importance of sandblasting and acid-etching parameters for a controlled titanium dental implant surface, which can achieve surface roughness parameters that correspond to those previously reported in the literature as favorable ones for osseointegration.

Objectives . The aim of this study is to develop and demonstrate an effective method for obtaining large-area, high-quality monolayers of molybdenum disulfide (MoS 2 ) on the surface of ferroelectric lead zirconate titanate (PZT) films which exhibit pronounced granularity and texturing. Conventional mechanical exfoliation techniques are inefficient for transferring two-dimensional materials onto nonplanar surfaces. This is due to local height variations and substrate granularity which hinder the formation of continuous monolayers and high-defect-density transferred structures. A particular challenge is the transfer onto functional substrates with surface topography characterized by heterogeneities ranging from tens of nanometers to micrometers. Methods . A gold-assisted exfoliation (GAE) method was employed, including: magnetron sputtering of a 50 nm gold film; mechanical delamination of monolayers using thermally cleavable tape; and subsequent gold etching. The characterization was performed using X-ray diffraction, optical confocal microscopy, atomic force microscopy, and second harmonic generation techniques. The efficiency of the transfer process was compared for Si/SiO 2 and PZT substrates. Results . MoS 2 crystallites with areas up to 3000 µm 2 were obtained on PZT and over 65000 µm 2 on standard Si/SiO 2 substrates, both of which exhibit minimal defect densities. Conventional mechanical exfoliation is shown to be unable to ensure transfer onto textured surfaces, whereas the GAE method preserves the monolayer character of the transferred crystallites even on nonplanar substrates. Conclusions . This work demonstrates for the first time the possibility of obtaining large-area, high-quality MoS 2 monolayers on substrates with pronounced grainy and textured structures, such as ferroelectric PZT films, using the gold-assisted exfoliation method. The work also shows that gold-assisted exfoliation is an effective technique for fabricating extended two-dimensional films with controlled morphological and structural properties, including on substrates previously considered unsuitable for such applications.

ABSTRACT The effectiveness of a coating system heavily depends on the surface texture characteristics of the underlying material, as these play a crucial role in determining how well the coating adheres. This adhesion is vital for maintaining the coating's integrity and ensuring reliable performance under demanding conditions. Key surface texture characteristics such as average roughness ( R a ), root mean square roughness ( R q ), maximum peak‐to‐valley height ( R z ), peak density ( N p ), and statistical properties like kurtosis ( R ku ) and skewness ( R sk ) of surface profiles directly influence the bonding strength between the coating and its substrate. This study is focused on investigating how different surface texture characteristics influence the adhesion strength and wear behavior of PEEK polymer coatings applied to mild steel through electrostatic spraying. To conduct this analysis, two substrates with distinct roughness profiles were coated with PEEK layers approximately 45 ± 5 μm thick, and their wear resistance was assessed using a ball‐on‐disk tribological test. Wear experiments were conducted over 10,000 cycles at room temperature under applied loads of 30, 40, and 50 N, with a constant sliding speed of 0.2 m/s. The findings revealed that coatings applied to rough surfaces withstood the full 10,000 cycles even at 50 N, whereas coatings on polished substrates failed after just 200 cycles under the same load. The superior performance of the rough surface is linked to its higher surface roughness, elevated R z values, and positive skewness ( R sk ), all of which contribute to more effective mechanical interlocking. In contrast, the smoother, polished surface, with its reduced roughness, lower R z , and negative R sk , provided fewer anchoring points, resulting in weaker adhesion of the coating.

ABSTRACT Slip‐related injuries and vehicle skids in low‐friction environments highlight the urgent need for advanced anti‐slip materials to improve safety and prevent accidents. This review summarizes the fundamental mechanisms of slipping, drawing on contact mechanics and a proposed friction behavior model for surface interfaces. Strategies to enhance anti‐slip performance such as surface texturing, chemical modification, and filler incorporation are discussed. Standardized evaluation methods, including friction testing, the British Pendulum Test, and the ramp test, are reviewed alongside other common assessment techniques. The practical applications of anti‐slip materials are explored, with emphasis on high‐risk areas like roadways and winter footwear. Challenges in achieving durable, high‐performance solutions are outlined, and future research directions are suggested. By integrating current advancements and practical considerations, this review supports the development of next‐generation anti‐slip systems aimed at enhancing safety and functionality across diverse applications.

Abstract Surface texture shapes and texturing methods were created to improve the tribological performance of mechanical systems. High-speed conventional micromachining in general and semihemispherical microdimples prepared through ball nose end milling in particular, have recently gained recognition as an effective method for improving tribological performance. The tribological behavior of semihemispherical microdimples created through ball nose end milling was investigated in this research at constant and accelerated sliding speeds. Experiments were conducted using an oscillating pin-on-disc arrangement with varying load (2 and 4 N), lubrication (0.2, 2, and 20 µl), and temperature (50, 100, and 150 °C) to replicate the characteristics of the piston–liner contact in an internal combustion engine. The coefficient of friction decreases with an increase in lubrication and a drop in load, sliding speed, and temperature across all evaluated surfaces. D40 surfaces exhibited better efficiency throughout most tribological test settings, with a mean texture efficiency of 26.86% for the evaluated conditions. Analysis of texture efficacy for the variation of linear speed similar to the piston-ring–liner interface at higher load and temperature suggests a novel approach to study the variation of friction for the variation of lubrication regimes in reciprocating motion. Overall, it was found that the textured surfaces with semihemispherical microdimples of 240 µm in diameter, 40 µm in depth, and 10% area density, created by conventional micromachining, are suitable for piston applications.

Abstract Removing graffiti from porous masonry remains a significant conservation challenge, in part as spray paint may penetrate the pores of the material. Historic brick is particularly vulnerable due to its softer texture and higher porosity compared with dense stone or modern brick, which increases the risk of paint absorption and surface alteration during cleaning. Micro-abrasive cleaning employs fine particles at low pressures to provide a relatively controlled method that minimizes direct chemical exposure, discoloration, and excessive material loss. However, the effects of this technique on historic brick have not been thoroughly investigated. In this study, cleaning performance is assessed through analyses of color and surface texture changes conducted before paint application and after cleaning trials. The extent to which the original fire-skin remains serves as an additional key indicator of the aggressiveness of this cleaning method. By integrating instrumental measurements with visual and tactile assessments, the study provides evidence-based insights into graffiti removal on historic brick and underscores considerations for conservation cleaning of sensitive masonry surfaces.

Abstract Surface texturing consists of introducing well-defined, intentional cavities on bearing surfaces, either on the housing or on the rotating shaft. For such configurations, it is well established in the literature that mass-conserving cavitation models are essential for accurately describing cavitation phenomena. However, the influence of thermal effects on the performance of textured bearings is often overlooked. This work addresses this gap by proposing a mass-conserving two-phase cavitation model that incorporates global thermal effects to assess the impact of surface texturing on load-carrying capacity, friction and temperature in hydrodynamic journal bearings. The pressure predictions are validated against full Navier-Stokes CFD simulations, while the friction and thermal responses are validated using experimental data for both smooth and textured bearings. The results demonstrate that friction-induced temperature rises modify bearing performance in the presence of textures, confirming that thermal effects are a critical factor and that conventional isothermal assumptions may be misleading for the accurate analysis and design of textured journal bearings.

Abstract A friction coefficient calculation model was developed based on the contact mechanics of rough surfaces to investigate the effect of surface texturing technology on the friction performance of a rotary sealing interface in a rotary vane actuator under start-up conditions. Furthermore, the Extended Fourier Amplitude Sensitivity Test method was employed to systematically analyze the influence of texture parameters on the friction coefficient. Results indicated that texture area ratio was the dominant factor affecting the friction coefficient, followed by the root mean square roughness. The influence of texture depth on the friction performance was relatively small within a given range. The four typical texture shapes analyzed had no significant effect on sensitivity ranking. Additionally, non-negligible interaction effects existed among the parameters, accounting for approximately 30-40% of the total sensitivity. This study provides a theoretical basis and valuable reference for further optimization of the texture parameters in the rotary sealing of rotary vane actuators.

Abstract This study addresses friction and wear challenges in finger seals for aero-engines and high-speed machinery via pin-on-disc tests. Laser-fabricated circular textures with varying diameters (200~400 μm) and densities (5%~30%) on GH4169 discs were tested against GH605 pins under dry friction. Real-time friction monitoring and SEM/EDS analyses revealed texturing mechanisms: debris trapping mitigated abrasive wear, reducing friction and wear. The optimal performance was achieved at a 200 μm diameter and 10% density, with a 17.45% reduction in friction coefficient, a 42.17% decrease in wear depth, and the formation of a uniform transfer film for stable contact. Excessive density (30%) induced stress concentration via reduced contact area, worsening wear; large diameters (400 μm) caused impact loads from insufficient contact units, increasing friction fluctuations. The synergy of debris trapping, contact stress regulation, and transfer film formation defines the texturing benefit. Results offer experimental guidance for high-speed/high-load finger seal surface design.

The role of laser surface texturing for environmentally friendly surface engineering applications: a review

Experimental study on the transport processes of different types of microplastics in rainfall runoff over urban road surface.

Enhanced leakage prediction in lubricating-oil static seals considering surface texture orientation

Abstract Traditional waste aluminum (Al) alloy sorting technologies face technical bottlenecks such as low efficiency and poor accuracy. Image-based classification methods struggle too accurately identify alloy compositions and grades due to the similar visual characteristics of surface textures of different Al alloys. Laser-induced breakdown spectroscopy (LIBS), as an emerging spectral analysis technique, offers the capability for rapid chemical composition analysis of samples. However, signal fluctuations and the spectral line interference caused by the matrix effects and heterogeneity constrain the analytical accuracy and stability of LIBS technology. Therefore, this paper proposes an improved ResNet18-SVM fusion classification model, by leveraging image-spectral bimodal data, to improve accuracy and robustness. It extracts image features via an improved lightweight ResNet18 network, combines them with LIBS spectral features processed by SVM, and employs a Random Forest classifier for final decision-making, achieves efficient and accurate classification. Experimental results demonstrate that the proposed model exceeds 97% on accuracy and recall metrics. It is significantly superior to the ResNet18 model based on pure images and the SVM method based on pure spectra. Furthermore, it achieves an 72% reduction in classification time compared to the original ResNet18 model, demonstrating high precision and efficiency. This model provides an effective solution for waste Al alloy intelligent sorting, holds broad application prospects.

The automotive, aerospace, biomedical, and other engineering sectors make substantial use of Ti6Al4V titanium alloy, known for its high strength-to-weight ratio, corrosion resistance, and biocompatibility, but it often suffers from poor tribological performance and low surface hardness. To increase durability, a variety of surface modification techniques have been investigated, including chemical etching, shot peening, thermal oxidation, laser surface texturing, and physical vapor deposition. However, these methods frequently entail high thermal input and mechanical stress with limited control over surface chemistry. Electrochemical methods, on the other hand, allow uniform and precise alteration of surface morphology without thermal or mechanical damage. Among these, anodization and plasma electrolytic oxidation (PEO) facilitate hardening and stress-free surfaces but suffer from passive film formation, porosity and micro-cracks, while electrochemical polishing (ECP) yields much better surface finish but at high energy cost and causes passive film formation. In this review, electrochemical machining (ECM), typically viewed as a subtractive method for material removal, is reevaluated as a process for both material removal and functional surface tailoring. Despite its application for removing material, ECM promotes valence-controlled dissolution that favours the formation of lower oxidation states of titanium. It also inhibits the formation of passive films and enables the formation of atomically smooth surfaces. The present study provides a novel theoretical framework for customizing Ti6Al4V surfaces with improved functional and morpho­logical properties by integrating ECM with anodization, PEO and ECP within the broader paradigm of electrochemical surface engineering.

Sustainable fog water harvesting through facile surface texturing

ABSTRACT Wear performance of the bearing couple in total hip prostheses is a critical determinant of implant longevity, patient outcomes, and the likelihood of revision surgeries. Among the various methods developed to evaluate wear behavior, computational approaches using finite element analysis have emerged as powerful tools due to their flexibility, cost‐effectiveness, and ability to simulate complex biomechanical interactions. This literature review focuses specifically on the application of Archard's wear law within finite element frameworks to predict wear in single mobility bearing of total hip prosthesis under walking conditions. Emphasis is placed on modeling methodologies, the incorporation of physiological gait cycles, boundary condition considerations, and validation through experimental data. The review also explores recent advancements aimed at improving simulation accuracy, including the use of multi‐directional loading, sliding trajectory mapping, and realistic material properties. Finally, future directions are discussed, such as duration of computational wear prediction, sliding trajectory, surface roughness and lubrication modeling in computational wear prediction, textured surfaces for wear reduction, surface coatings for enhanced wear resistance, dual mobility total hip prosthesis, and experimental validation and integration with computational modeling, all collectively aim to enhance predictive reliability and support the development of more durable, personalized orthopedic implants.

In this work, we demonstrate precise control over laser-induced periodic surface structures (LIPSS) on stainless steel (SS) using femtosecond (fs) laser processing to suppress bacterial adhesion. We systematically compare the antifouling behavior of laser-textured surfaces with distinct pattern directionalities—linear and circular. Fs laser irradiation with linear polarization produces directional and anisotropic LIPSS, which progressively evolve into more complex hierarchical surface textures as processing conditions vary. In contrast, fs laser irradiation with circular polarization yields isotropic surface morphologies. Despite these morphological differences, the surface wettability remains nearly constant, with contact angles confined to a narrow range of 32.6–36.9°. Bacterial adhesion tests using Escherichia coli reveal that surfaces patterned with anisotropic features generated by linear polarization—particularly at an incident power of 30 mW—exhibit enhanced antifouling performance compared to isotropic counterparts. These results indicate that antifouling efficacy is governed not only by surface wettability but also by the spatial organization and anisotropy of the LIPSS. This study highlights the critical role of polarization-controlled fs laser processing in tailoring surface architectures and provides a rational strategy for designing bio-resistant metallic surfaces.

The thermodynamic performance of a tapered roller bearing is governed by the irreversible dissipation within its lubricating film. Minimizing the total entropy generation rate, which arises from fluid friction and heat transfer, is paramount for enhancing mechanical efficiency and operational longevity. This study conducts a numerical investigation into the entropy optimization of a nanoparticle-enhanced Sutterby lubricant within a rough-walled, tapered bearing geometry. The flow is modeled using the continuity, momentum, and energy equations, coupled with an entropy transport equation. The non-Newtonian lubricant behavior is characterized by the Sutterby fluid model, with its shear-thinning intensity governed by the Weissenberg number ([Formula: see text]). The analysis focuses on the influence of key dimensionless parameters: the Reynolds number, the Hartmann number for magneto-hydrodynamic effects, and a defined surface roughness parameter. The analysis demonstrates that the total entropy generation, comprising frictional and thermal contributions is highly sensitive to the converging-diverging geometry. It is found that increasing the Weissenberg number significantly reduces the Bejan number, indicating a shift from thermal to viscous flow irreversibility dominance. Furthermore, the nanoparticle volume fraction directly enhances thermal transport, reducing the temperature gradient contribution to entropy generation. Optimal conditions for minimizing entropy are identified for specific combinations of Reynolds number, Weissenberg number and surface roughness. The results provide a rigorous thermodynamic framework for optimizing tapered bearing performance. By quantifying the interplay between rheology, inertia, and surface texture on the entropy generation map, this work establishes design criteria for minimizing irreversibility. This enables the development of high-efficiency lubrication systems utilizing advanced non-Newtonian nano lubricants.