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Due to the poor surface characteristics of additively manufactured parts, the necessity for post-process surface enhancement is crucial. Among the prevalent post-processing techniques, the acoustic cavitation-based surface finishing technique has recently emerged. Despite a considerable amount of focused research on the material removal mechanisms of this technique, less attention has been devoted to addressing its limitations associated with enhancing the process capability towards achieving a better surface finish. The driving force behind the acoustic cavitation technique is the bubble implosion through cavitation streaming, and the cessation of the acoustic cavitation streaming beyond a certain length is the main limitation. It has restrained the process capability towards finishing both external and internal surfaces. Hence, this research aims to unravel novel ways of employing the acoustic cavitation-generating parameters and achieving better-quality surface finishing of additively manufactured (AM) components. A study has been conducted on different AM materials, including Inconel 625 and aluminum alloy, by introducing various methods associated with acoustic amplitude, working mediums, temperature, and external vibration. The results reveal a significant reduction in average surface roughness for both materials. The topographical and morphological observations confirm the qualitative improvement on the surfaces. In addition, the conical bubble structures that frame the acoustic cavitation streaming are elucidated by implementing high-speed imaging techniques, and their enhancement at different parametric conditions is delineated. Henceforth, the findings suggest a notable insight into the potential of the employed approaches in enhancing the acoustic cavitation streaming for achieving a better surface finish of AM components. [Display omitted] • Surface finishing of AM components by enhanced acoustic cavitation. • Overcoming the limitations of acoustic cavitation for surface quality improvement. • Acoustic cavitation: factors affecting acoustic streaming and AM surface quality. • Thermal effect on bubble structures in free-field and confined acoustic cavitation. • A study on parametric investigation of acoustic cavitation: a different approach. [ABSTRACT FROM AUTHOR]

The lunar surface contains a wide variety of topographic shapes and features, each with different distributions and scales, and any analysis technique to objectively measure roughness must respect these qualities. Coarse‐graining is a naturally scale‐dependent filtering technique that preserves scale‐dependent symmetries and produces coarse elevation maps that gradually erase the smaller features from the original topography. In this study of the lunar surface, we present two surface variability metrics obtained from coarse‐graining lunar topography: fine elevation and coarse curvature. Both metrics are isotropic, deterministic, slope‐independent, and coordinate‐agnostic. Fine (detrended) elevation is acquired by subtracting the coarse elevation from the original topography and contains features that are smaller than the coarse‐graining length‐scale. Coarse curvature is the Laplacian of coarsened topography, and naturally quantifies the curvature at any scale and indicates whether a location is elevated or depressed relative to its neighborhood at that scale. We find that highlands and maria have distinct roughness characteristics at all length‐scales. Our topographic spectra reveal four scale‐breaks that mark characteristic shifts in surface roughness: 100, 300, 1,000, and 4,000 km. Comparing fine elevation distributions between maria and highlands, we show that maria fine elevation is biased toward smaller‐magnitude elevations and that the maria–highland discrepancies are more pronounced at larger length‐scales. We also provide local examples of selected regions to demonstrate that these metrics can successfully distinguish geological features of different length‐scales. Plain Language Summary: Planetary surface roughness is inherently scale‐dependent: a seemingly smooth surface can look rough if you zoom in enough. The converse can also hold: small‐scale rough features can look smooth if you zoom out enough. Therefore, it is important to have a way to measure surface roughness that accounts for variations in how "zoomed in" we are looking. In this work we use coarse‐graining, an approach that effectively blurs the lunar surface, allowing us to vary the "zoom" level as we are measuring surface variability. We present two ways of measuring the scale‐dependent variability of the lunar surface: coarse curvature (measures how curved the blurred surface is) and fine elevation (looks at everything that was removed by the blurring, and measures how much those smaller features contributed to the topography). Using our approach, we are able to incrementally change what is considered "small" and measure how the perception of the lunar surface changes as we are gradually zooming out of it. Our results highlight the dichotomy in roughness between the lunar maria and highlands. We also identify four key length‐scales where the roughness changes qualitatively, suggesting a change in the underlying physical processes that contribute to different kinds of roughness. Key Points: Two novel metrics for surface variability display distinct characteristics for highlands, maria, and various geological featuresTopographic spectra spanning 1–5,000 km identify four roughness characteristic changes that correlate with known crater distributionsFrequencies of fine elevation highlight and contrast scale‐ and terrain‐dependent behaviors between mare and highlands regions [ABSTRACT FROM AUTHOR]

This paper examined the surface morphology of maple and beech cut through by CO2 laser under different angles relative to the wood grain: 0°, 15°, 30°, 45°, 60°, 75°, and 90°. In the analysis, stylus measurements, stereo-microscopic images, and chemical changes were considered. Laser uncovers more wood anatomical details, with enhanced clarity, when the cutting transitions from along the grain to across the grain. This is particularly noticeable in the earlywood and is more pronounced in maple compared to beech. The first tissue of earlywood was deeply ablated by the laser, leading to a wavy anatomical pattern, which is more visible for higher angles of laser cutting in relation to the wood grain. The anatomical structure of beech was more affected by carbonization in comparison to maple and had a significantly higher core roughness, Rk. For both species, the worst surface roughness occurred when cutting at 15°. In maple, the laser caused more degradation of the polysaccharides compared to beech, and this impact was particularly noticeable parallel to the grain rather than at a 90° angle. The degradation of hemicelluloses occurred in parallel with more advanced cellulose degradation for beech compared to maple and for cutting along the grain compared to across the grain. Structural changes in lignin, such as condensation processes, were observed for both species. [ABSTRACT FROM AUTHOR]

The selective laser melting (SLM) technique applied to high-entropy alloys (HEAs) has attracted considerable attention in recent years. However, its practical application has been restricted by poor surface quality. In this study, the capability of laser polishing on the rough surface of a Co-free HEA fabricated using SLM was examined. Results show that the initial SLM-manufactured (as-SLMed) surface of the Co-free HEA, with a roughness exceeding 3.0 µm, could be refined to less than 0.5 µm by laser polishing. Moreover, the microstructure, microhardness, and wear resistance of the laser-polished (LP-ed) zone were investigated. Results indicate that compared with the microhardness and wear resistance of the as-SLMed layer, those of the LP-ed layer decreased by 4% and 11%, respectively, because of the increase in grain size and reduction of the BCC phase. This study shows that laser polishing has an excellent application prospect in surface improvement of HEAs manufactured by SLM. [ABSTRACT FROM AUTHOR]

Raw lacquer, known for its superior performance as a natural liquid coating, boasts excellent physical and mechanical properties as well as durability, making it widely used in manufacturing. However, the high hardness of the lacquer film upon complete curing poses challenges for carving and mechanical engraving. Therefore, it is necessary to study the curing process of lacquer films to obtain films suitable for carving or mechanical engraving. This study involves the preparation of raw lacquer with varying amounts of tung oil added, followed by the measurement of film drying time, surface roughness, glossiness, hardness, and adhesion on substrates to determine the optimal drying conditions. Additionally, SEM analysis of the carved surfaces and FT-IR analysis were used to investigate the impact of tung oil addition on lacquer carving performance and its variation. The results indicate that tung oil, to a certain extent, contributes to a smoother lacquer film but adversely affects film hardness and adhesion to Prunus serotina. However, with an increase in the amount of refined tung oil to 15%, the film exhibits improved glossiness, smoother carving tool marks, and reduced debris, thereby validating the feasibility of mechanical carving of tung oil-modified raw lacquer to some extent. [ABSTRACT FROM AUTHOR]

The aerospace industry has made extensive use of titanium alloy material due to its exceptional qualities, which include high strength, low weight, and resistance to corrosion. However, these qualities also pose challenges for the material's processing. This article examined the coated end mills for Ti6Al4V milling. First, an analysis was conducted on the solubility of Ti and Si elements. It was discovered that W and Co elements were far more soluble in Ti than Si and Zr elements, which could effectively stop element diffusion. Next, the base's composition was planned. It was discovered that when the amount of Al increased, the base's surface roughness increased, while its hardness and elastic modulus decreased. The binding force between the substrate and the base was greater at a 50:50 Ti:Al ratio. The H3/E2 was about 0.23 and the surface roughness was about 0.15 μm. TiSiN and TiSiN/ZrN functional layer properties were also examined. When Zr was added to TiSiN/ZrN coating, it improved the coating's hardness and elastic modulus, increased density, and decreased surface roughness and friction coefficient when compared to TiSiN coating. There was an increase in hardness by 8.09% and an increase in elastic modulus by 9.65%. The average coefficient of friction decreased from 0.315 to 0.299. Lastly, an analysis of the initial and intermediate tool wear was done using the Ti6Al4V milling experiment. It was discovered that adding Zr element could successfully extend the tool's cutting life by preventing adhesive wear. [ABSTRACT FROM AUTHOR]

Silane‐terminated Polyurethane (SPU) is in high demand in the sealant and adhesive industries because of its exceptional cohesive strength and excellent adhesive properties. To close a self‐curable SPU resin was synthesized using a two‐step solution polymerization process for 12 h at pH 2.8 using the sol–gel method. Subsequently, the polyurethane prepolymer's NCO moiety was terminated by VTMS silanol to prepare SPU resin. FTIR and liquid state NMR were used to study VTMS hydrolysis in an acidic medium. Explored the effects of VTMS on SPU properties, including crystallinity, Mn and Mw, viscosity, gel fraction, thermal, surface, and mechanical. FTIR and NMR (1H and 13C) spectra confirmed the successful termination of the prepolymer's unreacted diisocyanate with the hydroxyl moiety of silanol. XPS and FTIR were used to analyze the chemical structures of urethane, urea, siloxane, and the hydrogen bonds between SPU moiety. Increased wt% of silanol exhibits increased gel fraction (80%–91%) with a decreased degree of swelling (76%–45%) showing the formation of a cross‐linked structure. Including siloxane in polyurethane showed a synergetic effect, resulting in enhanced thermal stability through reduction of weight loss. The SPU exhibited a three‐stage degradation pattern, accompanied by decreased glass transition temperature and crystallinity. Siloxane enrichment increased SPU surface roughness (Rq‐218 and Ra‐69 nm) and hydrophobicity (94°–103°). Silane wt% increase causes significant changes in Young's (2.19–51 N/mm2) modulus, strain %, and adhesive strength (4.60–5.62 MPa). Silane‐terminated polyurethane can be used successfully as an adhesive and sealant. [ABSTRACT FROM AUTHOR]

Gyrofinishing is a mass-finishing process used for large and/or complex workpieces. In this process, abrasive media filled in a container are accelerated by rotating the container, impacting the workpiece fixed in it and smoothing the workpiece surface. In this study, the effects of the materials and sizes of the abrasive media on the surface roughness, microstructure, and residual stress on the specimen surface developed by gyrofinishing were revealed. The surface of the gyrofinished specimen was smooth. However, the specimen surface when using the HS medium, consisting of a mixture of ceramic and small abrasive grains, was slightly rougher compared to that finished using the PS medium, consisting of ceramic. An ultra-fine grained structure was formed at the surface after gyrofinishing, regardless of medium. A flow of the microstructure was observed in the specimens gyrofinished with the HS media, indicating that shear stress occurred during gyrofinishing. All the gyrofinished specimens exhibited a significant compressive residual stress near the surface. The residual-stress profile along the depth direction differed depending on the material and size of the media. The small media shallowed the depth of the maximum compressive residual stress (dmax), whereas the medium size hardly affected the maximum compressive residual stress (·max). The measured dmax was significantly smaller than the dmax value estimated based on the Hertz contact theory, which is likely due to the shear stress generated by the rotation or sliding of the media on the specimen surface during gyrofinishing. The specimens gyrofinished using the HS series had a higher ·max than those gyrofinised using the PS series. The rough surface of the HS medium is expected to introduce a high compressive residual stress through the burnishing effect. It can be concluded that gyrofinishing provides the specimen surface with a smooth, ultra-fine grained structure and significant compressive residual stress. [ABSTRACT FROM AUTHOR]

Mooring chains are key components of offshore floating photovoltaic systems. Although their service safety is often affected by the harsh service environment, the influence of surface roughness on their corrosion resistance is not clear. This study investigated the corrosion behavior of mooring chain steel using cyclic salt-spray corrosion and electrochemical tests. Scanning electron microscopy, energy-dispersive spectrometry, optical profilometry, and other analytical techniques were used to study the composition and morphology of the corrosion products. The corrosion behavior was studied by electrochemical polarization curves, alternating current impedance spectroscopy, and X-ray photoelectron spectroscopy. The results show that the salt-spray corrosion resistance of mooring chain steel significantly improved with the reduction in specimen surface roughness, and the number and depth of corrosion pits were reduced. Mass loss after 24 h of salt-spray corrosion was exponentially related to initial roughness ( Ra ). Improved surface roughness significantly increased the pitting potential of the specimens, widened the passivation range, and enhanced the repassivation capability, thus significantly improving the pitting resistance. The pitting potential is linearly related to the initial roughness of the specimen. The oxide contents of Fe, Mo, and Si in the passivation film tended to increase with a smoother surface, which contributes to its densification. This effectively blocks chloride ion attack, thus improving the corrosion resistance of the mooring chain steel. [ABSTRACT FROM AUTHOR]

The powder spreading process is a fundamental element within the laser powder bed fusion (PBF-LP) framework given its pivotal role in configuring the powder bed. This configuration significantly influences subsequent processing steps and ultimately determines the quality of the final manufactured part. This research paper presents a comprehensive analysis of the impacts of varying spreading speeds, which are enabled by different roller configurations, on powder distribution in PBF-LP. By utilizing extensive Discrete Element Method (DEM) modelling, we systematically examine how spreading speed affects vital parameters within the spreading process, including packing density, mass fraction, and actual layer thickness. Our exploration of various roller configurations has revealed that increasing spreading speed generally decreases packing density and layer thickness for non-rotating, counter-rotating, and forward-rotating rollers with low clockwise rotational speeds (sub-rolling) due to powder dragging. However, a forward-rotating roller with a high clockwise rotational speed (super-rolling) balances momentum transfer, enhancing packing density and layer thickness while increasing surface roughness. This configuration significantly improves the uniformity and density of the powder bed, providing a technique to accelerate the spreading process while maintaining and not reducing packing density. Furthermore, this configuration offers crucial insights into optimizing additive manufacturing processes by considering the complex relationships between spreading speed, roller configuration, and powder spreading quality. [ABSTRACT FROM AUTHOR]

Surface quality represents a critical challenge in additive manufacturing (AM), with surface roughness serving as a key parameter that influences this aspect. In the aerospace industry, the surface roughness of the aviation components is a very important parameter. In this study, a typical Al alloy, AlSi10Mg, was selected to study its surface roughness when using Laser Powder Bed Fusion (LPBF). Two Random Forest (RF) models were established to predict the upper surface roughness of printed samples based on laser power, laser scanning speed, and hatch distance. Through the study, it is found that a two-dimensional (2D) RF model is successful in predicting surface roughness values based on experimental data. The best and minimum surface roughness is 2.98 μm, which is the minimum known without remelting. More than two-thirds of the samples had a surface roughness of less than 7.7 μm. The maximum surface roughness is 11.28 μm. And the coefficient of determination (R2) of the model was 0.9, also suggesting that the surface roughness of 3D-printed Al alloys can be predicted using ML approaches such as the RF model. This study helps to understand the relationship between printing parameters and surface roughness and helps print components with better surface quality. [ABSTRACT FROM AUTHOR]

Titanium alloys, particularly Ti6Al4V, are widely used in biomedical applications due to their excellent mechanical properties and inherent biocompatibility. However, enhancing their surface characteristics, such as biocompatibility and corrosion resistance, remains a key challenge for their long-term use in medical implants. In this study, we investigate the effects of rhenium–carbon coatings deposited on Ti6Al4V substrates via magnetron sputtering, incorporating a molybdenum anchoring layer. X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) analyses confirmed the formation of rhenium carbides, elemental rhenium, and rhenium oxides within the coatings. Despite these successful depositions, scanning electron microscopy (SEM) revealed significant delamination and poor adhesion of the coatings to the Ti6Al4V substrates. Corrosion resistance, evaluated through potentiodynamic polarization tests, showed an increase in corrosion current densities and more negative corrosion potentials, indicating a detrimental effect on the substrate's corrosion resistance. Biocompatibility assessments using PK15 cells demonstrated a marked decrease in cell viability and metabolic activity, particularly in samples with higher surface roughness. These findings underscore the critical need for the optimization of surface preparation and deposition processes to improve both the adhesion and biocompatibility of rhenium–carbon coatings on Ti6Al4V substrates. Future research should aim to refine coating technique to enhance adhesion, explore the mechanisms of cytotoxicity related to surface roughness, and expand biocompatibility studies across different cell lines and biological environments. [ABSTRACT FROM AUTHOR]

Titanium and titanium alloys are the prevailing dental implant materials owing to their favorable mechanical properties and biocompatibility, but how roughness dictates the biological response is still a matter of debate. In this study, laser texturing was used to generate eight paradigmatic roughened surfaces, with the aim of studying the early biological response elicited on MC3T3-E1 pre-osteoblasts. Prior to cell tests, the samples underwent SEM analysis, optical profilometry, protein adsorption assay, and optical contact angle measurement with water and diiodomethane to determine surface free energy. While all the specimens proved to be biocompatible, supporting similar cell viability at 1, 2, and 3 days, surface roughness could impact significantly on cell adhesion. Factorial analysis and linear regression showed, in a robust and unprecedented way, that an isotropic distribution of deep and closely spaced valleys provides the best condition for cell adhesion, to which both protein adsorption and surface free energy were highly correlated. Overall, here the authors provide, for the first time, a thorough investigation of the relationship between roughness parameters and osteoblast adhesion that may be applied to design and produce new tailored interfaces for implant materials. [ABSTRACT FROM AUTHOR]

Spiral bevel gears are extensively employed in mechanical transmissions; however, they are prone to adhesive wear when operating under high-speed and heavy-load conditions. Research indicates that the tooth surface roughness of gears significantly influences the friction and wear of the meshing gears. The present study delves into the origins of tooth surface roughness through the integration of the W-M function and fractal theory. Utilizing an involute helical gear with surface roughness for tooth cutting, a three-dimensional model is established with roughened tooth surfaces. This paper introduces an approach to developing three-dimensional gear models with roughness and applies the finite element method to perform thermodynamic analysis on gears exhibiting diverse levels of surface roughness. The thermal analysis of gears with varying degrees of roughness was conducted using the finite element method. Comparative analysis of the results under specific operating conditions elucidated the impact of roughness on tooth surface temperature rise. In order to validate the simulation model, an experimental test platform for spiral bevel gears of identical size was established. This model integrates tooth surface roughness with thermodynamic analysis, allowing for the rapid assessment of tooth surface temperature rise under different machining conditions, and reducing the cost of validating predicted tooth surface load-carrying capacity. [ABSTRACT FROM AUTHOR]

This article presents a machine vision system for measuring the arithmetic average roughness of shot- and sand-blasted surfaces. In the developed system, a digital microscope was used for capturing surface images after shot- and sand-blasting processes. The captured grayscale images were analyzed with the proposed algorithm using Otsu's global thresholding and a size bandpass filter. The algorithm detected white regions associated with the specular reflection of light on a binary image, and then calculated the size of selected regions. One-way ANOVA was used to identify the relation between the size of the regions and the arithmetic average roughness of blasted surfaces. It was noted that the average size of white regions showed a linear relation to the arithmetic average roughness of both shot- and sand-blasted surfaces. Different abrasives (shot or sand) were found to bring about differences in the rate of change of the average size within a chosen roughness range. When a surface image with unknown roughness is given, it is possible to predict the arithmetic average roughness on the basis of the relation. This machine vision system enables the fast and low-cost roughness measurement of shot- and sand-blasted surfaces. Thus, it could be useful in a quality inspection for shot- and sand-blasting. [ABSTRACT FROM AUTHOR]

Cutting fluid can improve the heat dissipation and lubrication in the cutting process and thus increase the machining quality. In this work, a pollution-free alcohol solution was proposed as the cutting fluid in an ultra-precision cutting process to explore green cutting fluids. The scratching experiments were conducted with the alcohol cutting fluid to study its effect on the cutting process. It is found that the use of an alcohol cutting fluid, on average, reduces the tangential and normal force about 27–53%, but exhibits few effects on the friction coefficient in the cutting process. Compared to dry cutting, the alcohol cutting fluid reduces the exposed shear slip steps on the outside surface of the chip, which implies the decreased chip deformation degree of workpiece material in the cutting process. The alcohol cutting fluid can reduce microburrs and decrease the machined surface roughness Ra from 21 nm to 9.9 nm in the ultra-precision turning application on single-crystal copper material. [ABSTRACT FROM AUTHOR]

Carbonate formation is the key reservoir in Sichuan Basin for natural gas development. Compared with the early stage of development, the burial depth of targeted formation becomes deeper, and the formation temperature gets higher. So, the characteristics of acidizing effectiveness in high-temperature carbonate formations make this evaluation slightly difficult. Currently, it is common that a single parameter is considered to study acidizing effectiveness by simulation and experiment methods. In this paper, for a more accurate investigation of acidizing effectiveness, multiple parameters, including permeability change rate, fracture conductivity, and surface roughness, were introduced by a series of experiments. It is revealed that the permeability change rate is more than 57% when using gelled acid. As the amount of diverting agent increases in diverting acid, the viscosity of the acid grows to its peak with the reaction, making it easier to block the high permeability core temporarily and divert to acidify the low permeability core, where the permeability change rate of the low permeability core goes from 51.6% to 64.2%, which shows well acidizing effectiveness. In addition, the short-term and long-term conductivity of the samples from the three different formations are more than 200 mD∙m under high closure stress. The conductivity of Maokou Formation is the largest due to its high content of carbonate minerals and high dissolution rate. And the results of long-term conductivity are consistent with those of surface roughness, making the evaluation results more reliable for acidizing effectiveness. It is worth noting that temperature is a factor that cannot be ignored in the evaluation of acidizing effectiveness because it has a great influence on the performance of the acid system, such as viscosity and the reaction-reduced rate, leading to an acidizing effectiveness affect. So, the temperature resistance of an acid system is important as well. [ABSTRACT FROM AUTHOR]

This paper investigates the potential of utilizing lubricated liquid carbon dioxide (LCO2 + MQL) as an alternative to conventional flood cooling in grinding operations. This approach could facilitate a transition towards fossil-free production, which is a significant challenge in industry. The alternative cooling–lubrication method relies on pre-mixed LCO2 and oil and a single-channel minimum quantity lubrication (MQL) delivery method, which has already demonstrated potential in machining with geometrically defined cutting edges. However, this method has been less explored in grinding. This study primarily evaluates the grindability of AISI 4140 steel, examining surface roughness, residual stresses, microhardness, grinding forces, and specific energy for different cooling–lubrication methods. The results indicate that LCO2 + MQL is capable of attaining surface roughness and microhardness that is comparable to that of conventional flood cooling, especially in the case of less aggressive, finish grinding. Nevertheless, the presence of higher tensile residual stresses in rough grinding suggests that the cooling capability may be insufficient. While the primary objective was to evaluate the technological viability of LCO2 + MQL in terms of grindability, a supplementary cost-effectiveness analysis (CEA) was also conducted to assess the economic feasibility of LCO2 + MQL in comparison to conventional flood cooling. The CEA showed that the costs of both the cooling–lubrication methods are very similar. In conclusion, this study offers insights into the technological and economic viability of LCO2 + MQL as a sustainable cooling–lubrication method for industrial grinding processes. [ABSTRACT FROM AUTHOR]

To address issues such as large surface roughness, coarse grains, and poor mechanical properties in low-carbon steel parts produced through wire arc additive manufacturing (WAAM), this paper proposes a method combining multi-directional incremental forming with the WAAM process. The additive manufacturing and cooling processes were simulated using the finite element software Abaqus to analyze the effects of multi-directional additive manufacturing on the stress field of the fabricated parts. The results indicate that after multi-directional incremental forming, the residual stress in the fabricated parts shifts from tensile stress to compressive stress, thereby reducing the risk of defects such as cracks. Moreover, the equivalent plastic strain of the processed parts increases, and the surface microhardness improves, with the most significant impact of multi-directional incremental forming observed in the contact area of the rolling head. [ABSTRACT FROM AUTHOR]

The purpose of this research was to create a predictive model for a medium-speed wire electrical discharge machine (WEDM) utilizing an artificial neural network (ANN). Medium-speed WEDM experiments were developed based on the I-optimal mixture design for machining, the Inconel 718 superalloy. During the experiment, the input parameters were the spark ontime, spark offtime, wire feed, and current, with the material removal rate (MRR) and surface roughness (Ra) selected as performance indicators. The ANN model was trained on experimental data and built using a feed-forward backpropagation neural network with a (4-8-2) structure and the Bayesian regularization (BR) learning approach. The model correctly predicted the relationship between the medium-speed WEDM's primary process parameters and machining performance. An integrated ANN model and the Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) were used to determine the ideal parameters for the MRR and Ra, resulting in a set of Pareto-optimal solutions. The confirmation experiment revealed that the mean prediction error between the experimental and ideal solutions had a maximum error percentage of 1% for the MRR and 2% for the Ra, which are within acceptable ranges. This showed that the best process–parameter combinations were better for the MRR and Ra. [ABSTRACT FROM AUTHOR]

Die-sink electric discharge machining (EDM) is essential for shaping complex geometries in hard-to-machine materials. This study aimed to optimize key input parameters, such as the discharge current, gap voltage, pulse-on time, and pulse-off time, to enhance the EDM performance by maximizing the material removal rate while minimizing the surface roughness, residual stress, microhardness, and recast layer thickness. AISI 316L stainless steel was chosen due to its industrial relevance and machining challenges, while a Ti-6Al-4V-SiCp composite electrode was selected for its thermal resistance and low wear. Using Taguchi's L27 orthogonal array, this study minimized the trial numbers, with analysis of the variance-quantifying parameter contributions. The results showed a maximum material removal rate of 0.405 g/min and minimal values for the surface roughness (1.95 µm), residual stress (1063.74 MPa), microhardness (244.8 Hv), and recast layer thickness (0.47 µm). A second-order model, developed through a response surface methodology, and a feed-forward artificial neural network enhanced the prediction accuracy. Multi-response optimization using desirability function analysis yielded an optimal set of conditions: discharge current of 5.78 amperes, gap voltage of 90 volts, pulse-on time of 100 microseconds, and pulse-off time of 15 microseconds. This setup achieved a material removal rate of 0.13 g/min, with reduced surface roughness (2.46 µm), residual stress (1518.46 MPa), microhardness (259.01 Hv), and recast layer thickness (0.87 µm). Scanning electron microscopy further analyzed the surface morphology and recast layer characteristics, providing insights into the material behavior under EDM. These findings enhance the understanding and optimization of the EDM processes for challenging materials, offering valuable guidance for future research and industrial use. [ABSTRACT FROM AUTHOR]

Plastics reinforced with glass fiber have a significant likelihood of being replaced by natural fiber hybrid composites (NFHCs). Making holes helps in part assembly, which is a crucial activity in the machining of composite constructions. As a result, choosing the right drill bit and cutting parameters is crucial to creating a precise and high-quality hole in composite materials. The present study employs the Taguchi approach to examine the delamination behavior and hole quality of ramie–bamboo composite laminates consisting of epoxy and nano-fillers (SiC, Al2O3) with feed, spindle speed, and three distinct drill bit types. Surface roughness and delamination are significantly influenced by feed and spindle speed, as indicated by the results of the analysis of variance. It was found that the spindle speed had a major impact on the delamination factor and surface roughness, while the feed and drill bit type had a minor influence. The surface roughness (76.5%) and delamination factor (66.7%) are significantly affected by the spindle speed. [ABSTRACT FROM AUTHOR]

Shot peening is generally used to improve the fatigue performance of mechanical components. However, identifying the geometrical and mechanical characteristics of the shots that improve fatigue strength is still a challenging task, as there are many variables involved in the shot peening process. The present work addresses the effect of different shot media on the fatigue behaviour of an aluminium alloy 6082 T6. Four different shot types were used: silica microspheres, alumina shots, aluminium cut wire and zinc cut wire. Axial fatigue tests were carried out to obtain the Wöhler curves corresponding to each shot peening treatment. The surface properties of the shot-peened specimens, such as grain size, hardness, residual stress and roughness were measured to determine their effect on the fatigue results. The fatigue results revealed that silica and zinc shots increased significantly the fatigue life of the alloy, whereas alumina and aluminium shots reduced its fatigue strength. Almen intensities have shown to correlate well with grain refinement and strain hardening. However, better fatigue results were obtained with the shots that generated higher surface compressive residual stresses. It is believed that small and smooth shots are preferable to sharp and irregular ones, regardless of the Almen intensity or surface hardness attained with the latter. [ABSTRACT FROM AUTHOR]

Carbon-fiber-reinforced polymer (CFRP) composites are widely used across industries due to their enhanced strength and stiffness properties. Fused deposition modeling (FDM) enables the cost-effective production of polymer samples, such as carbon-fiber-reinforced PLA (CFR-PLA). However, CFRP's hardness and anisotropic nature present significant challenges in conventional machining, including rapid tool wear and thermal sensitivity. Consequently, abrasive water jet machining (AWJM) has proven to be an effective alternative for machining CFRP materials, offering benefits such as reduced tool wear, minimized thermal damage, and improved cutting quality. This study focuses on a comparative analysis of the effects of AWJM parameters on PLA and CFR-PLA samples, specifically to evaluate the influence of carbon fiber reinforcement on machining performance. The findings highlight the critical role of reinforcements in machining behavior. The results suggest that optimizing cutting parameters significantly reduces taper formation and improves machining accuracy. In particular, adjustments to process parameters resulted in lower taper angles and reduced surface roughness in the cutting zones of the CFR-PLA samples. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Lead halide perovskites are notorious for water-sensitivity and low hardness. Consequently, polishing CsPbBr3 crystals to achieve high-quality surfaces is challenging. We present a breakthrough mechanical polishing methodology tailored to the specific needs of these soft, moisture-sensitive semiconductors. Three-dimensional optical surface profiles over ~ 1 mm2 areas demonstrate high-quality surfaces with root-mean-square roughness values (< 10 nm) that are unparalleled for melt-grown CsPbBr3. We additionally delve into the polished wafers' fundamental optical constants and introduce an anti-reflection coating method, setting new standards for short-wave infrared transparency in CsPbBr3. These pivotal processing guidelines pave the way for advancing halide perovskite applications beyond academic curiosity. [ABSTRACT FROM AUTHOR]

Investigating the shear characteristics of the contact surface between tunnel surrounding rock and lining under different normal stresses and roughness conditions has significant theoretical and engineering importance for further research on the interaction between tunnel surrounding rock and lining, as well as the stability of rock mass. To consider roughness conditions, fractal theory was adopted to generate five different contact surfaces by changing the fractal dimension D and fractal roughness G in the fractal formula. Based on the two-dimensional particle flow code (PFC2D ), a numerical shear model of the contact surface with dimensions of 150 mm x 150 mm was established. Numerical shear tests were carried out for the same contact surface under different normal stresses and for different contact surfaces under the same normal stress. In order to verify the reliability of the numerical simulation, shear stress-shear displacement curves obtained from a typical numerical shear test were compared with those obtained from the laboratory shear test. The research results showed that: (1) The cracks generated by shear failure in the numerical model were mainly concentrated at the middle contact surface, with stress after failure mainly concentrated at points with the greatest contact surface roughness. The failure cracks could be divided into shear cracks and tensile cracks, with tensile cracks being predominant. (2) Shear stress-shear displacement curves exhibited three stages: climbing, cutting and sliding, with obvious peak strength and residual strength. Normal displacement increased with increasing shear displacement, resulting in dilatancy effect. (3) With the increase of normal stress, the number of shear and tensile cracks increased, failure phenomena became more pronounced. Peak strength and residual strength increased, and the dilatancy effect decreased. (4) With increasing roughness undulation, i. e., an increase in fractal dimension D or a decrease in fractal roughness G, the number of failure cracks increased, especially tensile cracks, as well as peak strength and residual strength. The dilatancy effect also intensified. [ABSTRACT FROM AUTHOR]

Drilling cooling holes on the turbine blade is essential for enhancing aero engine performance and to protect it from elevated temperature. So, the objective of this work is to produce micro holes on the thermal barrier coated titanium alloy using a femtosecond laser. An in-depth experimental investigation has been carried out to understand the influence of femtosecond laser parameters, circular and zig-zag scanning modes on geometrical characteristics and surface integrity of the micro holes. It is inferred that better hole circularity and less taper angle are observed for circular scanning method at laser energy density (LED) of 2.04 J/cm2, pulse repetition rate (PRR) of 20 kHz, and scanning speed of 300 mm/s. The surface finish and hole quality are also improved by this method, although at higher LED and PRR the inner hole wall surface degrades because of flaws including microcracks, re-solidified material, and micropores. When compared to circular scanning, the zig-zag scanning strategy reduces the drilling time by 51.87%. Conical spike with micro protrusion and micro trench type microstructure, is noticed for the zig-zag path. In contrast, micropores with micro protrusion type microstructures are obtained for concentric path with minimal surface flaws. [ABSTRACT FROM AUTHOR]

In this paper, parameters that effectively contribute to glass surface degradation from sandblasting erosion processes are investigated and optimized on the basis of the method of Taguchi. The polystyrene glass used in this work has been eroded taking into account the projected sand mass, the particles' grain size and the velocity as the main influencing parameters by looking at specimens' surface roughness (SR) and optical transmission (OT). Taguchi's Design L9 orthogonal array of experiments has been implemented in order to obtaining the best combination among these parameters. The significant parameters affecting the responses have been determined on the basis of variance analysis. These have revealed that the particles' size and velocity are the most effective parameters on the responses OT and SR of the degraded surface with 92 and 56% contribution, respectively. These optimized influential parameters' combinations have revealed severe eroding processes occurring to the polystyrene glass surface as confirmed by the optical micrographs. [ABSTRACT FROM AUTHOR]

Ball burnishing has been an effective surface finishing process that generally requires pressing hardened steel rolls/balls, during feed motion, into the surface of the metallic workpiece. The purpose of this study is to examine the improvement of the burnished surface quality by optimizing several burnishing factors, including ball diameter (d), depth of penetration (p), number of passes (N) and type of lubricants (L) for improving surface quality of AISI 1010 steel plates. A second-order mathematical model is developed to predict the surface quality as functions of ball burnishing parameters. The optimal burnishing parameters were determined by conducting central rotatable design matrix experiments and predicting the response models for the surface roughness and hardness. The optimal burnishing conditions for the steel plates were found by using a ball diameter of 12 mm, a burnishing depth of 0.25 mm, a number of passes of 5 and 15W-40 (L3) for the type of lubricant. With these optimal parameters, the mean surface roughness is reduced from Ra = 2.48 to Ra = 0.37 µm, while Brinell hardness increases from 59 to 70.88 HRB. The results show that all lubricants used in this study had negligible effect on the surface hardness. [ABSTRACT FROM AUTHOR]

This research focused on investigating the impact of nitrocarburization on the surface characteristics and tribological properties of SKH51 high-speed tool steels. We performed various heat treatment procedures, including single tempering quenching (QT1), double tempering quenching (QT2), triple tempering quenching (QT3), and a combination of double tempering quenching followed by nitrocarburization (QT2N). We evaluated attributes such as 3D surface morphology, tribological attributes, surface roughness, and hardness. The results revealed that the QT2N resulted in samples with a rougher surface and approximately 4.4 times harder than the untreated specimen (AR). Moreover, these samples were approximately 1.4 times harder than those subjected to QT3. Surface roughness was observed to increase after quenching and multiple tempering processes. However, the surface roughness of the QT2N specimen was reduced due to the formation of a compound layer following the nitrocarburizing process. The retained austenite of QT3 and QT2N demonstrated a lower standard deviation than those of AQ, QT1, and QT2, owing to the transformation of retained austenite into tempered martensite and precipitated carbide. The compound layer formed during nitrocarburization enhanced surface hardness, improved surface roughness, and reduced the coefficient of friction. Consequently, the QT2N process demonstrated greater efficiency than QT3, suggesting that nitrocarburization can effectively replace the final tempering process. This adaptation could result in a simplified heat treatment procedure and lower production costs. [ABSTRACT FROM AUTHOR]

Hydrological similarity is an index to measure the similarity degree of two basins, which is often used to identify and select similar basins. Traditional research usually only discriminates whether there is similarity between basins, but pays little attention to the spatial and temporal characteristics of hydrological similarity of basins. In order to explore the spatio-temporal variation characteristics of hydrological similarity in the Fenhe River Basin, this paper set the calculation time scale based on the different meteorological elements of the year, month and day, set the sub-watershed scale according to the different river grades of the first, second and third levels nested in the Fenhe River basin, and carried out principal component analysis on 5 meteorological elements and 17 underlying surface indicators in the study area. Finally, the hydrological similarity evaluation system of Fenhe River Basin was established with the average annual precipitation, average annual temperature, topographic humidity index, topsoil PH, average elevation and surface roughness as the characteristic indexes, and the coefficient of variation method was used to determine the hydrological similarity weight coefficient of the basin, and the temporal and spatial characteristics of the hydrological similarity of the main and tributary basins of Fenhe River were quantitatively studied. The results show that: 1 the hydrological similarity between the first-level Fen River basin and the Fen River basin is greater than 0.750 on the scale of year, month and day. Under the three time scales, the hydrological similarity between the main stream of Fanwang River and Fenhe River basin is the highest, which is 0.908, 0.927, 0.910 in order. At the annual scale, the hydrological similarity between the main stream of Dachuan River and Fenhe River basin is the lowest, which is 0.773. On the monthly scale, the hydrological similarity between Changyuan River and Fenhe River basin is the lowest, 0.818. On the daily scale, the hydrological similarity between ZhongMafang River and Fenhe River basin is the lowest, which is 0.791. 2 At different sub-watershed scales, the hydrological similarity gradually decreases with the decrease of the river series of Fen River's nested tributaries. The hydrological similarity of the first to third tributaries of Lanhe River, Changyuan River, Wenyu River and Fanwang River with respect to Fenhe River basin is 0.845, 0.814, 0.736, 0.800, 0.891, 0.794, 0.811, 0.772, 0.722, 0.908, 0.738, 0.725. 3 Hydrological similarity is positively correlated with the characteristic indexes. The coefficient of determination of terrain moisture index, topsoil PH and hydrological similarity regression equation are 0.573 3 and 0.894 6, respectively, showing a significant and high correlation, while the other characteristic indexes are weakly correlated with hydrological similarity. The research results are of great significance for hydrological forecasting and parameter transplantation in areas without data in Fenhe River Basin. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this research was to evaluate how different concentrations of TeO2 filler particles influence the thermal conductivity, hardness, and surface roughness of room-temperature-vulcanizing VerSiltal 50 silicone elastomeric materials. Materials and Methods: A total of 90 samples were prepared by varying the weight percentages of TeO2 powder (0, 3, and 5 wt. %). Thirty samples from each group were used in the analysis. Two experimental groups with 3 and 5 wt. % of TeO2 fillers were prepared and subjected to thermal conductivity, surface hardness, and surface roughness tests. The data were analyzed using descriptive statistics and analysis of variance with multiple comparison tests, and a P value < 0.05 indicated significance. Results: Thermal conductivity and hardness improved as the percentage of TeO2 increased from 3 wt. % to 5 wt. %, compared with those in the control group, whereas surface roughness decreased. Conclusion: The means for thermal conductivity and surface hardness of the 3 and 5 wt. % TeO2 experimental groups increased significantly relative to those in the control group. [ABSTRACT FROM AUTHOR]

The effects of soluble ions on the morphology and crystal growth of calcium sulfate hemihydrate whiskers are very significant. In order to gain a deeper understanding of the basic theory of regulating whiskers, this paper summarises the progress of research on the effects of different types and concentrations of soluble cations in desulfurization gypsum on the whisker preparation. The low concentration of Na+ has a small effect on the calcium sulfate hemihydrate whiskers and barely affects the morphology and surface smoothness of the whiskers. The content of K+ is suitable to be 3% (mass fraction) or below, and the higher content has a detrimental effect on the growth of calcium sulfate hemihydrate whiskers. Mg2+ makes the whisker surface more homogeneous and crystalline. And the trace amount of selective adsorption of Al3+ has no effect on the whisker length-to-diameter ratio. Similar to K+, Fe3+ also has the optimal concentration, which is lower than 2 mmol / L. Unlike the cations mentioned above, Cu2+ is not from the raw material, but is an additional ion introduced in the doping of the appropriate amount of Cu2+ is conducive to the formation of whiskers with a smooth and uniform surface. [ABSTRACT FROM AUTHOR]

Efficient cutting of float glass can be achieved by using 532 nm nanosecond laser with the bottom-up spiral scanning method. Due to the obvious thermal effect when the nanosecond laser acts on the glass, it will cause glass edge chipping, white spots on the side wall surface, surface micro cracks and voids and other defect behaviors. Focusing on this problem, the single-factor experimental method was used to explore 532 nm laser hole cutting defect behavior. The results show that the laser pulse frequency is the key factor affecting the defect shape. Improper pulse frequency and pulse energy will seriously increase the glass edge chipping and the surface roughness of hole wall, and also produce uneven regional white spots. Increasing the scanning speed will reduce the surface roughness of hole wall. Smaller spiral overlap rate will cause the corrugated surface morphology of glass hole wall. When the hole wall quality is poor, the micro cracks and voids are more obvious. [ABSTRACT FROM AUTHOR]

Space‐wall‐climbing robots face the challenge of stably attaching to and moving on spacecraft surfaces, which include smooth flat areas and rough intricate surfaces. Although adhesion‐based wall‐climbing robots demonstrate stable climbing on smooth surfaces in outer space, there is scarce research on their stable adhesion on rough surfaces within a microgravity environment. A novel adhesive material is developed inspired by the adhesion mechanism and locomotion of the Gekko gecko. This material exhibits exceptional adhesion across various materials and surface roughness. A variable‐stiffness gecko‐inspired paw is engineered, generating substantial adhesion forces while minimizing detachment forces. Impressively, this paw generates up to 180 N of adhesion force on smooth surfaces and achieves detachment without external forces. By integrating such variable‐stiffness paws with a wall‐climbing robot, a gecko‐inspired robot effectively operating in a microgravity environment is created. The robotic satellite surface climbing experiments and robotic satellite capture experiments are conducted using a simulated microgravity environment and a satellite model. The results unequivocally demonstrate the gecko‐inspired robot's proficiency in executing various functions, including stable motion and capture on both smooth and rough spacecraft surfaces within a microgravity environment. These experiments underscore the potential of adhesion‐based gecko‐inspired robots for in‐orbit services and spacecraft capture and recovery. [ABSTRACT FROM AUTHOR]

The present study investigates the impact of the electrode surface roughness on the electrofreezing of water. This research focuses on how the electrode microstructure induced by a laser treatment affects the nucleation and growth of ice crystals under controlled electric fields. For this, electrofreezing experiments of deionized water over electrodes with varying surface roughnesses and crystalline textures were conducted. The electrodes of the Al6061 T6 alloy were microstructured via the Laser Shock Processing (LSP) method. For this purpose, the pulse densities during the LSP process were varied (900, 1600, and 2500 pulses/cm2). The increase in pulse density was correlated to the microstructural features and average roughness of the LSP-treated Al6061 alloy. A wave-like microstructure was induced upon the LSP treatment, with roughnesses between 3.5 and 6 µm at the selected pulse densities. The results indicate that electrode roughness significantly influences the electrofreezing process. Rougher electrodes were found to increase the nucleation temperature, suggesting enhanced ice nucleation activity. These findings are attributed to the increased electric field concentration at the asperities of the rough surfaces and the (111) planes of the Al6061 alloy, which may facilitate the alignment of water molecules and the formation of critical ice nuclei. [ABSTRACT FROM AUTHOR]

Surface roughness is a critical factor in restorative dentistry, as it influences both the esthetic and functional outcomes of dental materials. The choice of abrasive powders used during the air polishing of dental restorations can significantly impact the surface roughness, potentially affecting the longevity and performance of the restoration. This study aimed to compare the effects of three different air-polishing powders—sodium bicarbonate, erythritol, and glycine—on the surface roughness of a 3M Filtek™ Supreme XTE (3M St. Paul, Minnesota 55144-1000) United States composite resin and a Fuji™ IX glass ionomer cement. This study also examined how different application times (5 and 10 s) influenced these outcomes. Materials and Methods: An in vitro study was conducted using standardized blocks of 3M Filtek™ Supreme XTE composite resin and Fuji™ IX glass ionomer cement. Each material was treated with sodium bicarbonate, erythritol, and glycine at two different exposure times (5 s and 10 s) using a professional air-polishing device. Surface roughness (Ra) was measured before and after the treatments using a contact profilometer. The data were statistically analyzed using ANOVA and Tukey's post hoc test to compare the mean roughness values among the different groups, with a significance level set at p < 0.05. Results: The results showed significant differences in surface roughness between the materials, powders, and application times. The composite resin exhibited lower roughness and variability compared with the Fuji™ IX, indicating a more uniform and predictable surface. Sodium bicarbonate produced the highest roughness values, particularly after 10 s of application, while glycine resulted in the lowest roughness with greater variability. Erythritol produced intermediate roughness with moderate variability. For the Fuji™ IX, sodium bicarbonate caused the greatest variability in roughness, while glycine produced the smoothest surfaces. The ANOVA results confirmed significant differences in mean roughness among the abrasive groups, with Tukey's post hoc test showing that glycine had significantly lower roughness than sodium bicarbonate, and erythritol had higher roughness than glycine but was lower than sodium bicarbonate. Conclusions: This study demonstrated that the choice of air-polishing powder and application time significantly affected the surface roughness of both 3M Filtek™ Supreme XTE composite resin and Fuji™ IX glass ionomer cement. Glycine consistently produced the smoothest surfaces, making it a preferable option for clinical scenarios where minimal surface roughness is desired. Sodium bicarbonate, while effective in cleaning, resulted in rougher surfaces, particularly after longer exposure times. These findings suggest that careful selection of polishing powders can enhance the esthetic and functional outcomes of dental restorations, contributing to their longevity. [ABSTRACT FROM AUTHOR]

Aim: The study aimed to compare the depth of cure, hardness, surface roughness, and wear resistance of four restorative materials used in pediatric dentistry: FUJI IX GP FAST, RivaSilver, SDR flow+, and Vertise Flow. Materials and Methods: The depth of cure was measured per ISO 4049 standards using a digital caliper, with 15 samples of each material. Hardness was evaluated using a Vickers indenter under a 10 N load for 20 s. Surface roughness was assessed before and after acid exposure using an optical profilometer according to ISO 4288. Brushing wear resistance was analyzed by subjecting samples to 20 and 60 min of brushing, followed by roughness measurements. Statistical analysis was performed using independent sample t-tests to determine the significance of differences between the materials, with p-values < 0.05 considered significant. Results: SDR flow+ exhibited the highest depth of cure with an average of 3.5 mm (±0.2 mm), significantly higher than Vertise Flow at 2.8 mm (±0.3 mm) (p < 0.001). Hardness testing revealed SDR flow+ had the highest average hardness (85 HV ± 4 HV), while Vertise Flow had the lowest (72 HV ± 5 HV) (p < 0.001). Surface roughness increased significantly after acid exposure for RivaSilver (from 1.2 μm ± 0.12 μm to 1.6 μm ± 0.15 μm, p = 0.007) and for SDR flow+ (from 0.85 μm ± 0.08 μm to 1.3 μm ± 0.14 μm, p = 0.001). Brushing wear resistance was highest in RivaSilver (Ra increase from 1.2 μm to 1.4 μm ± 0.11 μm) and lowest in FUJI IX GP FAST (Ra increase from 1.5 μm to 1.9 μm ± 0.15 μm, p < 0.001). Conclusions: The study demonstrates significant differences in performance among the tested materials. SDR flow+ showed a superior depth of cure and hardness, making it suitable for high-stress applications. However, all materials displayed increased surface roughness following acid exposure and brushing, with FUJI IX GP FAST showing the highest wear. These findings highlight the need to select restorative materials based on the specific clinical demands of pediatric patients, considering both their mechanical properties and resistance to wear and acid. [ABSTRACT FROM AUTHOR]

Aluminum alloy AlSi10Mg is a widely used engineering material that offers a very high strength‐to‐weight ratio and easy processing. It is common in the aerospace, medical, and automotive industries and has excellent machining and casting properties, as well as being easily made into fine powder. In recent years, it has become one of the most common light‐weight materials for additive manufacturing (AM). Its chemical composition and stability in powder form make it particularly ideal for laser powder bed fusion (LPBF) applications. It is one of the few available aluminum alloys that can be reliably processed using AM. Numerous studies have been dedicated to mechanical properties and design strategies, but much less attention has been given to corrosion behavior. This article reviews the corrosion behavior and the correlation between the microstructure and corrosion for AlSi10Mg when fabricated using an LPBF process. Specific topics reviewed include corrosion performance, corrosion issues (pores, surface roughness, and residual stresses), and passive film formation mechanisms and compare these to conventionally‐manufactured counterparts. In addition, this review discusses available methods for mitigating and avoiding corrosion in LPBF‐processed AlSi10Mg parts, including relevant post‐processing methods. [ABSTRACT FROM AUTHOR]

During implant maintenance, preserving a smooth surface on the machined transmucosal abutment is critical to reduce biofilm attachment and colonization. The present study compared the surface roughness and bacterial colonization of machined titanium surfaces after instrumentation with various materials. Forty-four machined grade 23 titanium discs were instrumented with a round polyether ether ketone (PEEK) tip, a plastic curette tip, or a pure titanium curette tip with piezoelectric devices. Before and after instrumentation, the surface roughness (Ra and Rz) values were analyzed with a profilometer and scanning electron microscopy (SEM). Streptococcus sanguinis was cultured and incubated for 24 hours on the instrumented discs, and colony-forming units per milliliter were obtained for each group. Samples instrumented with the metal ultrasonic tip significantly increased surface roughness compared with the other groups. This resulted in greater colonization by S. sanguinis than surfaces instrumented with PEEK tips or the negative control. Samples instrumented with PEEK and plastic tips did not exhibit any statistically significant increase in surface roughness, and SEM analysis revealed a significantly rougher surface of discs instrumented with metal compared with discs instrumented with plastic or PEEK tips despite the possibility of debris from tip dissolution. Our results suggest that instrumentation with metal ultrasonic tips with piezoelectric devices significantly increased machined titanium's surface roughness and elicited higher biofilm formation in vitro. Meanwhile, instrumentation of machined titanium with PEEK or plastic ultrasonic tips did not affect the surface roughness or bacterial adhesion. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of polishing and denture cleansers on the surface roughness (Ra) of new‐generation denture base materials that are additively, subtractively, and conventionally fabricated, while also assessing their color change after cleansing. Material and Methods: One hundred and fifty disk‐shaped specimens (Ø10 × 2 mm) were prepared from five denture base materials (one subtractively manufactured nanographene‐reinforced prepolymerized polymethylmethacrylate (PMMA) (SM‐GC), one subtractively manufactured prepolymerized PMMA (SM‐PM), two additively manufactured denture base resins (AM‐DT and AM‐ND), and one heat‐polymerized PMMA (CV) (n = 30). The Ra of the specimens was measured before and after conventional laboratory polishing, while color coordinates were measured after polishing. Specimens were then divided into three subgroups based on the denture cleanser: distilled water, 1% sodium hypochlorite (NaOCl), and effervescent tablet (n = 10). The Ra and color coordinates were remeasured after nine cleansing cycles over a period of 20 days. The CIEDE2000 formula was used to calculate the color differences (ΔE00). Two‐way analysis of variance (ANOVA) was used to analyze the Ra values before (n = 30) and after (n = 10) cleansing, while repeated measures ANOVA was used to analyze the Ra of material‐time point pairs within each denture cleanser (n = 10). ΔE00 data after denture cleansing was also analyzed by using two‐way ANOVA (n = 10) (α = 0.05). Results: Before polishing, Ra varied significantly among the materials. SM‐GC and SM‐PM had the lowest and AM‐ND the highest Ra values (P < 0.001). Polishing significantly reduced Ra of all materials (P < 0.001), and after polishing, Ra differences among materials were nonsignificant (P ≥ 0.072). Regardless of the denture cleanser, the Ra of AM‐DT, AM‐ND, and CV was the highest before polishing when different time points were considered (P < 0.001). After cleansing, AM‐ND had the highest Ra of all the materials, regardless of the cleanser (P ≤ 0.017). AM‐DT had higher Ra than SM‐PM when distilled water (P = 0.040) and higher Ra than SM‐GC, SM‐PM, and CV when NaOCl was used (P < 0.001). The type of cleanser significantly influenced the Ra of AM‐DT, AM‐ND, and CV. For AM‐DT, NaOCl led to the highest Ra and the tablet led to the lowest Ra (P ≤ 0.042), while for AM‐ND, distilled water led to the lowest Ra (P ≤ 0.024). For CV, the tablet led to lower Ra than distilled water (P = 0.009). Color change varied among the materials. When distilled water was used, SM‐GC had higher ΔE00 than SM‐PM and AM‐DT (P ≤ 0.034). When NaOCl was used, AM‐ND had higher ΔE00 than SM‐GC, SM‐PM, and AM‐DT, while CV and SM‐GC had higher ΔE00 than SM‐PM and AM‐DT (P ≤ 0.039). Finally, when the tablet was used, AM‐ND and CV had the highest ΔE00, while AM‐DT had lower ΔE00 than SM‐GC (P ≤ 0.015). Conclusions: The tested materials had unacceptable surface roughness (>0.2 μm) before polishing. Roughness decreased significantly after polishing (<0.2 μm). Denture cleansers did not significantly affect the surface roughness of the materials, and roughness remained clinically acceptable after cleansing (<0.2 μm). Considering previously reported color thresholds, AM‐ND and CV had unacceptable color change regardless of the denture cleanser, and the effervescent tablet led to perceptible, but acceptable color change for SM‐GC, SM‐PM, and AM‐DT. [ABSTRACT FROM AUTHOR]

Background: Self-adhesive resin cements (SARCs) are widely used for fixed prostheses, but incomplete cleaning near the gingival margin can cause inflammation. However, the factors influencing cement properties and the biological response of gingival fibroblasts to cement eluates are not well understood. This study examines the impact of two light-polymerizing units (LPUs) on the physical and chemical properties of two SARCs under simulated clinical conditions, as well as the subsequent response of human gingival fibroblasts (hGFs) to these eluates. Methods: Dental cement discs of SARCs were polymerized using Kerr DemiPlus and 3 M Elipar DeepCure-S LED LPUs with or without a 2-mm thick zirconia screen. Physical properties (microhardness, surface roughness, residual monomers) were evaluated. hGFs' cell viability, wound healing potency, and gene expression were assessed. Results: Both Maxcem and RelyX exhibited reduced microhardness and increased surface roughness when polymerized through zirconia or with DemiPlus LPU. Higher residual monomers (HEMA and GDMA in Maxcem; TEGDMA in RelyX) concentration was observed with DemiPlus and zirconia polymerization. Maxcem polymerized with DemiPlus exhibited lower cell viability, impaired healing, and altered gene expression in hGFs compared to those polymerized with Elipar LPU. Gene expression changes included downregulated NRF2 and HO-1 and upregulated CCR-3. Conclusions: Light-polymerizing Maxcem through zirconia with DemiPlus LPU compromised SARCs' properties, leading to higher residual monomers and negatively impacting hGFs' viability, healing, and gene expression. Careful material selection and polymerization techniques are crucial to minimize adverse effects on surrounding tissues. Clinical significance: Clinicians should exercise caution when using LPUs and SARCs, especially when polymerizing through zirconia. This will help optimize the physical and chemical properties of SARCs and minimize potential adverse effects on the surrounding gingival soft tissues. [ABSTRACT FROM AUTHOR]

Titanium and its alloys are popular materials for medical application, particularly in implant devices, where high mechanical properties and osseointegration are critical factors for successful implantation. In this work, the progress in the studies of nanostructured commercially pure Grade 4 titanium (nanoTi) is demonstrated, in which an ultrafine‐grained structure with nanoscale grain size is formed using severe plastic deformation processing. Nanostructured Grade 4 Ti has a very high strength, and its physical nature and strengthening mechanisms are analyzed herein. NanoTi proved also to have very high osseointegration during in vivo experiments. At the same time, the highest biofunctionality is demonstrated by the etched nanoTi samples with pronounced surface roughness, the latter being revealed from precise roughness measurements. The present study provided convincing evidence of accelerated bone formation on nanoTi, which is very promising for manufacture of dental and maxillofacial implants. [ABSTRACT FROM AUTHOR]

Objective of current study is to examine the machining characteristics of Al6082 composites embedded with multi-walled carbon nanotubes (MWCNTs). Herein, chemical vapor deposition (CVD) technique was used to develop MWCNTs. Stir-squeeze casting method was used to develop 0.3 wt.%−1.2 wt.% MWCNTs/Al6082 composites. Morphology of MWCNTs was analyzed by field emission scanning electron microscopy (FESEM). FESEM analysis was performed for as-cast nanocomposites which showed uniform spreading of MWCNTs up to 0.9 wt.% and beyond that clusters of MWCNTs were observed. Hardness and tensile strength of nanocomposites were also measured to observe the impact of addition of MWCNTs. Al6082 composites reinforced with 0.9 wt.% of MWCNTs showed highest hardness and tensile strength. It is important to examine the drilling characteristics as CNT in tube form may become constraint if they are not uniformly distributed and may obstruct tool movement. CNC electric discharge machining (EDM) and CNC milling machine were used to perform the drilling operation on nanocomposites with varying cutting parameters. It was noticed that inclusion of MWCNTs enhanced material removal rate (MRR) and surface finish of composites owing to enhanced brittleness. Strong interfacial bonding between MWCNTs and Al6082 matrix reduced the delamination during drilling operation. [ABSTRACT FROM AUTHOR]

In this failure analysis, the bump-type foil journal bearing (BFJB) is developed with various foil materials such as spring steel EN42J, phosphor bronze, Inconel X750, and SS 316. Subsequent failure analysis of the BFJB is conducted under low-speed operating conditions to evaluate their rubbing performance using the RSM technique. The study examined rotor speed and load as variable parameters, with wear rate (WR) and surface roughness (SR) of the BFJB as output responses. Additionally, a thermal imager is used to measure the rubbing temperature of the BFJB. The results indicated that Inconel X750 demonstrated superior tribological characteristics for the BFJB. With an increase in load, the wear rate of the BFJB increased while the surface roughness decreased. Among all foil materials, Inconel X750 had the most significant impact on surface roughness. The optimal values for rotor speed (S) and load (P) to enhance BFJB performance are 500 rpm and 10 N, respectively. Under these optimal conditions, the BFJB with Inconel X750 as the foil material exhibited a wear rate of 0.0150 mg/s and a surface roughness of 2.085 μm. Moreover, the BFJB made with phosphor bronze displayed the minimum rubbing temperature. [ABSTRACT FROM AUTHOR]

TiAlSiN gradient coatings were applied onto a cemented carbide steel substrate using cathodic arc ion plating technology. High-temperature oxidation experiments were conducted on the coatings in a box-type Maffei furnace to investigate the impact of thermal exposure temperature and duration on the surface morphology and wear characteristics of the TiAlSiN gradient coatings. The study revealed that the surface flatness of the coating remained stable after exposure to temperatures between 600 and 800°C for 1 h, with no oxides detected in the physical phase analysis. However, at 900°C, the surface flatness deteriorated, and TiO, TiO2, and Al2O3 oxides were identified. Subsequent tests at 800°C for 0.5, 1, and 2 h showed that the coating maintained good surface flatness, dominated by AlN and TiN phases, with no oxide formation. Specifically, at 800°C for 1 h, the coating exhibited reduced surface roughness and wear volume compared to 900°C for the same duration, by 0.03% and 39% respectively. After 2 h at 800°C, the wear volume was 2.13 times that of 1 h at the same temperature. Overall, the TiAlSiN gradient coatings demonstrated excellent wear resistance and thermal stability at high temperatures of 600°C and 700°C, as well as at 800°C for 0.5 and 1 h. [ABSTRACT FROM AUTHOR]

The major activity in research of metal cutting is to derive the mathematical models for surface roughness in turning. The present work aims at experimental investigation of hard turning of AISI 52100 bearing steel in order to determine the combined effects of tool geometry (nose radius and rake angle) and process parameters (speed, feed and depth of cut) on the performance characteristic surface roughness. Experiments were conducted using orthogonal array and central composite face centered (CCF) design. A mathematical prediction model for SR has been obtained in terms of factors mentioned. 3D response graphs were drawn to study the interaction effects of surface roughness. Prediction for orthogonal array is done through artificial neural network. Optimization of surface roughness was also carried out for CCF design using genetic algorithm. The efficacy of the CCF design over orthogonal array design is evaluated. Minimum surface roughness of 0.985 µm is obtained when A = 90m/min, B = 0.052mm/rev, C = 0.6mm, D = 4mm and E = − 12O after application of genetic algorithm. [ABSTRACT FROM AUTHOR]

Purpose: Cardiac tissue engineering is suggested as a promising approach to overcome problems associated with impaired myocardium. This is the first study to investigate the use of BC and gelatin for cardiomyocyte adhesion and growth. Methods: Bacterial cellulose (BC) membranes were produced by Komagataeibacter xylinus and coated or mixed with gelatin to make gelatin-coated BC (BCG) or gelatin-mixed BC (mBCG) scaffolds, respectively. BC based-scaffolds were characterized via SEM, FTIR, XRD, and AFM. Neonatal rat-ventricular cardiomyocytes (nr-vCMCs) were cultured on the scaffolds to check the capability of the composites for cardiomyocyte attachment, growth and expansion. Results: The average nanofibrils diameter in all scaffolds was suitable (~ 30–65 nm) for nr-vCMCs culture. Pore diameter (≥ 10 µm), surface roughness (~ 182 nm), elastic modulus (0.075 ± 0.015 MPa) in mBCG were in accordance with cardiomyocyte requirements, so that mBCG could better support attachment of nr-vCMCs with high concentration of gelatin, and appropriate surface roughness. Also, it could better support growth and expansion of nr-vCMCs due to submicron scale of nanofibrils and proper elasticity (~ 0.075 MPa). The viability of nr-vCMCs on BC and BCG scaffolds was very low even at day 2 of culture (~ ≤ 40%), but, mBCG could promote a metabolic active state of nr-vCMCs until day 7 (~ ≥ 50%). Conclusion: According to our results, mBCG scaffold was the most suitable composite for cardiomyocyte culture, regarding its physicochemical and cell characteristics. It is suggested that improvement in mBCG stability and cell attachment features may provide a convenient scaffold for cardiac tissue engineering. [ABSTRACT FROM AUTHOR]