Surface Roughness Research Articles

Quality Evaluation of Effective Abrasive Grains Micro-Edge Honing Based on Trapezoidal Fuzzy Analytic Hierarchy Process and Set Pair Analysis

Studying the factors affecting machining accuracy, surface quality, and machining efficiency in the powerful honing machining process system, analyzing the basic law between various errors and machining quality, exploring the method of evaluating the quality of honing, and improving the machining quality and transmission performance of hardened gears has important engineering application value. Firstly, this paper establishes an effective abrasive grains micro-edge honing quality evaluation model, proposes a method based on the Trapezoidal Fuzzy Analytic Hierarchy Process (Tra-FAHP) and Set Pair Analysis (SPA) to comprehensively evaluate the quality of the honing process, and obtains the influence weights of each factor on the quality of honing. Secondly, the paper analyzes the influence rules of three types of abrasive grain sizes on helix error, tooth pitch error, tooth profile error, surface roughness, and honing efficiency. Finally, the correctness of the established comprehensive evaluation model of honing quality was verified with the threshold method and weights. The research results show that the model can correctly evaluate the quality of hardened gear honing and can be applied to studying the influence of abrasive grain micro-edge honing on machining characteristics.

Refined speckle contrast estimation in OCT based on compensation of scattering-related distortions of speckle pattern parameters

Abstract Speckle contrast (SC) parameters in optical coherence tomography (OCT) scans are formed by the interplay of several factors—local level of optical wave backscattering by the material inhomogeneities, parameters of spatial distribution of the latter and the degree of cumulative optical wave attenuation during its fourth-and-back propagation. For the optical wavelengths used in OCT, this attenuation is usually dominated by the influence of scattering in the visualized turbid tissues rather than by absorption. For sufficiently high concentrations of scatterers (at least a few scatterers in the coherence volume) characterized by comparable scattering strengths and a fairly homogeneous distribution in space, the interference of locally scattered waves should be characterized by a Rayleigh distribution of speckle amplitudes, for which the local SC tends to 0.52. Equivalently, in terms of speckle intensities, the local SC tends to unity. Local spatial inhomogeneities or strongly uneven scattering strengths lead to the appearance of increased values of SC, which may serve as a diagnostic feature of some tissue components in OCT images. At the same time, in comparison to surface speckles formed by coherent-light scattering from rough surfaces, OCT-beam attenuation during its fourth-and-back propagation may introduce intensity inhomogeneities in OCT scans even for homogeneous tissue areas. This effect results in artefactual distortion of the visible SC in comparison with the above-mentioned expected value. Moreover, the presence of individual strong scatterers may additionally non-locally distort SC values due to the appearance of elongated shadows below such scatterers, which causes lateral inhomogeneities in OCT scans. Here, we propose a refined SC parameter, which is cleaned from distorting scattering-related effects in both axial and lateral directions. Depth-resolved estimation of the optical attenuation coefficient is used to restore attenuation-free OCT scans, for which the refined SC is estimated. The efficiency of the proposed approach is demonstrated using both digital OCT phantoms with highly controlled properties and experimental OCT data.

Rheological and Tribological Properties of Konjac Gum-Lecithin Composite System: Effect of Incorporation of Saliva and Friction Surface Properties.

This research explored the development of composite systems using konjac gum (KGM) and soy lecithin at concentrations of 1% KGM-0.01% lecithin and 1% KGM-0.2% lecithin. The study investigated the influence of both oral and artificial saliva on the rheological and tribological properties of these systems, as well as the lubrication on different friction surfaces with varying characteristics. It has been found that different friction surfaces exhibited distinct morphological features and roughness values, significantly impacting surface wettability when treated with saliva. The viscosity of KGM-lecithin composite systems increased slightly compared to KGM hydrogel. However, adding oral or artificial saliva led to a noticeable decrease in viscosity. Lecithin did not significantly alter the viscoelastic properties of KGM gel, but the incorporation of artificial and oral saliva introduced some changes. CLSM images showed that the stability and distribution of lecithin within the composite system varied with lecithin concentration and saliva type, with artificial saliva ensuring a stable and even distribution, while oral saliva caused aggregation and irregular distribution. Furthermore, the study found that the lubrication performance of the KGM-lecithin system was influenced by the properties of the friction surface, with hydrophilic rough surfaces providing superior lubrication compared to rough surfaces. The addition of lecithin enhanced lubrication across all tested surfaces, and artificial saliva surpassed oral saliva in reducing friction coefficients. These findings offer valuable insights into the potential use of KGM-lecithin composite systems as fat mimetics, particularly in enhancing lubrication for various applications.

Comparative Study of Surface Modification Techniques for Enhancing Biocompatibility of Ti-6Al-4V Alloy in Dental Implants

Comparative Study of Surface Modification Techniques for Enhancing Biocompatibility of Ti-6Al-4V Alloy in Dental Implants

Airborne-Particle Abrasion vs. Hydrofluoric Acid Etching of Dental Ceramics: Impact on the Tensile Bond Strength

This study evaluated whether airborne-particle abrasion could be an alternative to hydrofluoric acid etching as a pretreatment for the adhesive bonding of silicate ceramic restorations. Feldspar (FEL; n = 100), lithium silicate (LiSi; n = 100), and zirconia (ZrO2; (n = 80) substrates were CAD/CAM-fabricated and airborne-particle-abraded with Al2O3 (25 µm or 50 µm of mean particle size) at pressures of 0.05 or 0.1 MPa. The controls included FEL (60 s) and LiSi (20 s) etched with hydrofluoric acid. The surface free energy (SFE) and roughness (Ra) were measured. For the tensile bond strength (TBS), surfaces were conditioned using a primer (Monobond Plus) and luted to a resin composite (Variolink Esthetic). TBS was assessed initially (24 h, 37 °C water storage) and after thermocycling (5/55 °C, 10,000×). Statistical analysis (SPSS, V29) was performed using a one-way ANOVA, post hoc Scheffé, and a two-group t-test (p = 0.05). Abrasion with 50 µm and 0.1 MPa induced the highest Ra values across the materials (62.5 ± 3.88 µm). ZrO2 exhibited a higher TBS (35.4–49.5 MPa) than FEL and LiSi. For aged LiSi, the specimens treated at 0.1 MPa showed a higher TBS (18.7 ± 9.0 MPa) than those treated at 0.05 MPa, regardless of the particle size. The etched and aged FEL showed a higher SFE but a lower TBS compared to abrasion. Al2O3 particle abrasion (25 or 50 µm at 0.1 MPa) may replace etching for silicate-based ceramics, while 50 µm is recommended for ZrO2 at either pressure.

Roughing Nitrogen-Doped Carbon Nanosheets for Loading of Monatomic Fe and Electroreduction of CO2 to CO

The catalyst is the pivotal component in CO2 electroreduction systems for converting CO2 into valuable products. Carbon-based single-atom materials (CSAMs) have emerged as promising catalyst candidates due to their low cost and high atomic utilization efficiency. The rational design of the morphology and microstructure of such materials is desirable but poses a challenge. Here, we employed different Mg(OH)2 templates to guide the fabrication of two kinds of amorphous nitrogen-doped carbon nanosheet-supported Fe single atoms (FeSNC) with rough and flat surface structures. In comparison to flat FeSNC with saturated FeN4 sites, the rough FeSNC (R-FeSNC) exhibited unsaturated FeN4−x sites and contracted Fe-N bond length. The featured structure endowed R-FeSNC with superior capacity of catalyzing CO2 reduction reaction, achieving an exceptional CO selectivity with Faradaic efficiency of 93% at a potential of −0.66 V vs. RHE. This study offers valuable insights into the design of CSAMs and provides a perspective for gaining a deeper understanding of their activity origins.

Effects of surface roughness of a wave plate on the development of diffractive polarization speckle

Effects of surface roughness of a wave plate on the development of diffractive polarization speckle

Asperity interaction induced vibration excitation of cylindrical roller bearings with localized defect

Asperity interaction induced vibration excitation of cylindrical roller bearings with localized defect

Dissolution Behavior of M5 Cladding in Hydrofluoric–Nitric Mixed Acid

M5 cladding has emerged as a prominent fuel cladding material due to its excellent corrosion resistance. The dissolution behavior of M5 cladding is critical in both the initial cleaning stage and the reprocessing of spent fuel cladding. This study investigated the dissolution of M5 cladding in hydrofluoric–nitric (HF-HNO3) mixed acid at varying concentrations. When the HF concentration exceeds 0.5 mol/L, the addition of strong oxidizing HNO3 significantly reduces the dissolution rate. Moreover, HNO3 effectively inhibits the HF-induced corrosion pitting, lowering surface roughness to 0.812 μm at a 1:5 ratio of HF:HNO3. In addition, a surface structural analysis reveals the dissolution mechanism of M5 cladding. The β-Nb precipitated in the mixed acid was oxidized to stable Nb2O5 by HNO3 while the M5 matrix surface was continuously oxidized to ZrO2. This passivation layer inhibits further dissolution, slowing the process and enhancing the uniformity of M5 cladding.

Research on Stability of Removal Function in Figuring Process of Mandrel of X-Ray-Focusing Mirror with Variable Curvature

Over the past 30 years, researchers have developed X-ray-focusing telescopes by employing the principle of total reflection in thin metal films. The Wolter-I focusing mirror with variable-curvature surfaces demands high precision. However, there has been limited investigation into the removal mechanisms for variable-curvature X-ray mandrels, which are crucial for achieving the desired surface roughness and form accuracy, especially in reducing mid-spatial frequency (MSF) errors. It is essential to incorporate flexible control in deterministic small-tool polishing to improve the tool’s adaptability to curvature variations and achieve stable, Gaussian-like tool influence functions (TIFs). In this paper, we introduce a curvature-adaptive prediction model for compliance figuring, based on the Preston hypothesis, using a compliant shaping tool with high slurry absorption and retention capabilities. This model predicts the compliance figuring process of variable-curvature symmetrical mandrels for X-ray grazing incidence mirrors by utilizing planar tool influence functions. Initially, a variable-curvature pressure model was developed to account for the parabolic and hyperbolic optical surfaces’ curvature characteristics. By introducing time-varying removal functions for material removal, the model establishes a variable-curvature factor function, which correlates actual downward pressure with parameters such as contact radius and contact angle, thus linking the variable-curvature surface with a planar reference. Subsequently, through analysis of the residence time distribution across different TIF models, hierarchical filtering, and PSD distribution, real-time correction of the TIFs was achieved to enable customized variable-curvature polishing. Furthermore, by applying a time-varying deconvolution algorithm, multiple rounds of flexible polishing iterations were conducted on the mandrels of a rotationally symmetric variable-curvature optical component, and the experimental results demonstrate a significant improvement in form accuracy, surface quality, and the optical performance of the mirror.

Effect of Mechanical Surface Treatment on Shear Bond Strength of Orthodontic Brackets to 3D Printed and Milled CAD/CAM Provisional Materials: An In Vitro Study

The aim of the study is to assess the impact of mechanical surface treatments on the shear bond strength (SBS) of orthodontic brackets bonded to three-dimensional (3D) printed and milled CAD/CAM provisional materials. Sixty cylindrical samples were fabricated for each provisional material. Samples were treated with one of the following surface treatments: aluminum oxide airborne particle abrasion, diamond bur rotary instrument roughening, and phosphoric acid etching (control). Stainless steel brackets were bonded to the samples, and then SBS was tested using a universal testing machine. SEM and digital microscopy were utilized to examine the bonding interface and the failure modes. Two-way ANOVA, one-way ANOVA, Tukey’s HSD, and independent sample t-tests were used for statistical analysis. Results revealed significant differences in SBS between 3D printed and milled samples and significant differences in SBS among most surface treatments, with rotary instrument roughening resulting in the highest values for 3D printed, while airborne particle abrasion leading for milled samples. Digital microscopy indicated that more adhesive remained on 3D-printed samples. SEM analysis revealed varying surface roughness across treatments. Based on the findings of this study, it can be concluded that different surface treatments improve the bonding of orthodontic brackets to provisional crowns.

Effect of random roughness on Stokes flow

Microscopic irregularity (roughness) of bounding surfaces affects macroscopic dynamics of fluid flows. Its effect on bulk flow is usually quantified empirically by means of a roughness coefficient. A new approach, which treats rough surfaces (e.g. parallel plates) as random fields whose statistical properties can be inferred from measurements, is presented. The mapping of a random flow domain onto its deterministic counterpart, and the subsequent stochastic averaging of the transformed Stokes equations, yield expressions for the effective viscosity and roughness coefficient in terms of the statistical characteristics of the irregular geometry of the boundaries. The analytical nature of the solutions allows one to handle surface roughness characterized by short correlation lengths, a challenging feature for numerical stochastic simulations.

An improved line contact model for elastic–plastic rough surfaces

An improved line contact model for elastic–plastic rough surfaces

Investigation on the Cutting Performance of High‐Speed Dry Milling for 30CrMnSiNi2A Steel

High‐speed dry milling (HSDM) technology is one of the most attractive solutions for improving the cutting performance of difficult‐to‐machine materials. However, the study of HSDM performance for 30CrMnSiNi2A steel has not been reported. In this article, HSDM for 30CrMnSiNi2A steel is investigated using TiN‐coated and AlTiN‐coated tools, focusing on cutting force, vibration, surface roughness, residual stress, and tool wear. The effects of cutting parameters on cutting force and vibration are remarkably similar. At a spindle speed of 7500 r min−1, both cutting force and vibration are minimized. TiN‐coated and AlTiN‐coated tools exhibit distinct performance differences. But, HSDM of 30CrMnSiNi2A steel using TiN‐coated and AlTiN‐coated tools can achieve low surface roughness. The depth of cut significantly affects surface roughness, which is lowest at the depth of cut (0.8 mm). Most of the workpiece surface shows residual compressive stress. The main wear mechanisms for both coated tools are abrasive wear, adhesive wear, and oxidative wear. Furthermore, the AlTiN‐coated tool is more wear resistant on the flank face compared to the TiN‐coated tool. Chipping due to crater wear is the leading cause of tool failure for the AlTiN‐coated tool. Upon various comparisons, the AlTiN‐coated tool is more suitable for HSDM of 30CrMnSiNi2A steel.

Exploring temperature effects on compatibility in PS‐b‐PI‐b‐PS block copolymer‐based blends through experimental and molecular dynamics simulation approaches

AbstractThe poly(styrene‐block‐isoprene‐block‐styrene) (PS‐b‐PI‐b‐PS) block copolymer is known for its self‐assembly characteristics and dual structure that combines rubber and thermoplastic materials. Conventionally, blends of block copolymers are fabricated using the melt blending method, a process that requires high temperatures. This study introduces an energy‐efficient solution blending method to enhance the compatibility between PS‐b‐PI‐b‐PS and natural rubber (NR) latex. NR latex was blended with PS‐b‐PI‐b‐PS in toluene at temperatures of 80, 100, 120, and 150°C and cast to form films. The solution‐blended film prepared at a moderate temperature of 120°C exhibited a maximum tensile strength of 9.48 MPa and was thermally degraded at higher temperature (382°C) than those produced by melt blending. The solution blending method also reduced the surface roughness and the particle size to between 7 and 500 nm and improved the interfacial adhesion in SB‐120°C blend compared to MB‐180°C blend. Molecular dynamics simulations indicated that the improved mechanical performance of the blend was primarily due to enhanced intramolecular bonding, with a maximized bond energy of 20,133 kcal/mol. This work demonstrates an energy‐efficient method with lower processing temperature for preparing polymer blends with improved compatibility suitable for various nanotechnology and engineering applications.Highlights Solution blending method improves the compatibility. Tensile strength and interfacial adhesion of the polymer blend improved. Solution blending reduces the particle size and surface roughness. Simulation shows an increase in intramolecular bond energy.

A novel experimental approach to exploring process parameters for fabricating support-free horizontal overhangs in LPBF of Inconel 718

ABSTRACT The design freedom of Laser Powder Bed Fusion (LPBF) components has been confined by the minimum allowable overhang angle of 45°. It remains unclear how to achieve multiple layers of overhang at zero-degree overhang angle, which is the fundamental basis of overhang. Here, we have confirmed the possibility of manufacturing three layers of support-free 0° overhang, but also demonstrated the robustness of the present approach via the successful manufacture of an overhang with 18 mm span. The stable dross thickness reveals that the laser drilling effect did not penetrate beyond the three-layer overhang. Furthermore, this research also demonstrates that the failure to manufacture long bridge overhangs was caused by severe consolidation rather than the conventional understanding of residual stress of the first few layers. The high correlation between porosity and surface roughness, and the etched melt pool reveal the underlying mechanism for low surface roughness for the horizontal overhang. Highlights An experimental approach is proposed to efficiently explore the parameter space. The present approach enables the manufacture of three layers of support-free overhang. The mechanisms for the successful and failed prints are elucidated. The relationship of Ra and porosity is proposed to further refine the parameters.

Effect of Photolithographic Biomimetic Surface Microstructure on Wettability and Droplet Evaporation Process

In nature, engineering technology and daily life, wetting phenomena are widespread and have essential roles and significance. Bionics is becoming increasingly important nowadays and exploring the mechanism that influences biomimetic surface microstructure on droplet wetting process and heat and mass transfer characteristics is becoming more meaningful. In this paper, based on photolithography technology, SU-8 photoresist was used as raw material to prepare biomimetic surfaces with microstructures in various arrangements. The research results show that the wettability of biomimetic functional surfaces can be regulated by regulating the shape and arrangement of photoresist micro-pillars. At the same time, the effects of surface microstructure configuration and roughness on the heat and mass transfer processes within the droplets were also comprehensively studied. The results show that a biomimetic surface with cylindrical micro-pillars can effectively inhibit the evaporative cooling effect of the liquid–vapour interface. This effect becomes more evident with the increase in roughness, and the interface temperature difference can be reduced by up to 18%. Similarly, the biomimetic surface with cylindrical micro-pillars can also effectively promote the evaporation rate of sessile droplets, which can be increased by about 13%. In addition, the research also shows that regardless of the structure, substrate temperature changes will significantly impact the wetting phenomenon of the biomimetic surface. This study aims to guide the optimal design of biomimetic surfaces prepared based on photoresistance.

The New Interpretation of the Photothermal Spectra of CdTe Samples After Different Surface Treatments

This article presents new research on the surface condition of bulk crystal samples after the following stages of surface treatment: grinding, polishing, and etching. Furthermore, it shows how the surface condition affects the photothermal signal’s spectral amplitude and phase characteristics (PZE). A new theoretical interpretation of the photothermal spectra of CdTe samples after different surface treatments is proposed. We demonstrate that the piezoelectric method is susceptible to the surface condition, and it allows for the estimation of the thickness of surface-damaged layers of samples, and for the analysis of their thermal parameters. The roughness of surfaces obtained from the AFM pictures is estimated and compared to the photothermal results.

Analytical design of fourth and fifth harmonic generations of an elliptically polarized Bessel-Gauss beam by using the concept of guided wave optics and TIR-QPM technique in a biaxial material

This paper demonstrates the analytical design of an Elliptically polarized Bessel-Gauss beam-based frequency converter by using the guided wave optics concept and Total Internal Reflection Quasi phase matching technique. An anisotropic positive biaxial crystal featuring a rectangular structure of Rubidium Titanyle Phosphate has been used to carry out this analysis. The efficiency of the fourth and fifth harmonic conversion in the projected scheme is 7.05% and 4.3%, respectively, which is approximately three times greater than in a crystal length of approximately 1.4[Formula: see text]mm and 3.4[Formula: see text]mm, as provided by the scheme illuminated by a linearly polarized Bessel-Gauss beam at a wavelength of 735[Formula: see text]nm and 588[Formula: see text]nm, respectively. The influence of limiting factors, viz Goos Hänchen Shift, surface roughness, absorption, and the diffraction effect rooted in the basic law of nonlinear reflection, has also been taken care of in this analysis. The dependence of conversion efficiency on the length, thickness and angle of incidence of the slab has also been studied.

Numerical Study on the Influence of Drift Angle on Wave Properties in a Two-Layer Flow

This study examines the influence of drift angle on the wave and flow field generated by a submarine navigating through a density-stratified fluid. Employing a numerical methodology, this research computed the viscous flow field around the SUBOFF bare hull under conditions of oblique shipping maneuvers. The analytical framework relies on the Reynolds-Averaged Navier–Stokes (RANS) equations, supplemented by the Re-Normalization Group (RNG) k-ε turbulence model and the Volume of Fluid (VOF) method. The initial phases of this study involved verifying grid convergence and the accuracy of the numerical methods used. Subsequently, numerical simulations were performed across a spectrum of drift angles while maintaining a fixed Froude number of Fn = 0.5, with submergence depths set at 1.1 D and 2.0 D. The analysis focused on the wave profiles at both the free surface and the internal surface. The results indicate that the presence of a drift angle produces significant alterations in the characteristics of the free surface and internal surface when compared with straight-ahead motion. Specifically, the asymmetry in the flow field is enhanced, and the variability in the roughness of the free surface is pronounced.