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Objective: To evaluate the effect of the deterioration of computer aided design/computer aided manufacturing (CAD/CAM) burs during zirconia milling, on surface roughness, contact angle, and fibroblast viability. Materials and Methods: Ceramic blocks were milled and 75 ceramic disks (8 × 1.5 mm) made and allocated into three groups (n = 25): G1‐brand new 2L and 1L burs, G2‐2L bur at the end of lifetime and brand new 1L bur and G3‐both burs at the end of their lifetimes. Roughness (Ra, Rq, and Rz) was evaluated using a 3D optical profilometer, the contact angle by the sessile drop method and the cell viability of the mouse NIH/3T3 fibroblast, using the Alamar Blue assay at intervals of 24, 48, and 72 h (ISO 10993‐5). Data were analyzed by one‐way ANOVA and Kruskal–Wallis tests (p ≤ 0.05). Results: Roughness increased as the burs deteriorated and G3 (0.27 ± 0.04) presented a higher value for Ra (p < 0.001). The highest contact angle was observed in G3 (86.2 ± 2.66) when compared with G1 (63.7 ± 12.49) and G2 (75.3 ± 6.36) (p < 0.001). Alamar Blue indicated an increase in cell proliferation, with no significant differences among the groups at 24 and 72 h (p > 0.05). Conclusions: The deterioration of the burs increased the surface roughness and decreased the wettability, but did not interfere in cell viability and proliferation. Clinical Significance: The use of custom zirconia abutments represents an effective strategy for single crowns restorations. Our findings suggest that these abutments can be efficiently milled using CAD/CAM burs within their recommended lifetime. [ABSTRACT FROM AUTHOR]

The surface roughness of metal nanoparticles is known to be influential toward their properties, but the quantification of surface roughness is challenging. Given the recent availability of large‐scale simulated data and tools for the computation of the box‐counting dimension of simulated atomistic objects, researchers are now enabled to study the connections between the surface roughness of metal nanoparticles and their properties. Herein, the relationships between the fractal box‐counting dimension of metal nanoparticle surfaces and structural features relevant to experimental and computational studies are investigated, providing actionable insights for the manufacturing of rough nanoparticles. This approach differs from conventional concepts of roughness, but introduces a possible indicator for their functionalities such as catalytic performance that was not previously accessible. It is found that, while it remains difficult to consistently correlate the dimension with the catalytic activity of surface facets, matching trends with their surface energy, thermodynamic stability, and number of bond vacancy are observed. This highlights the potential of fractal box‐counting dimensions to rationalize catalytic activity trends among metal nanoparticles, and opens up opportunities for the design of nanocatalysts with better performance via surface engineering. [ABSTRACT FROM AUTHOR]

Scots pine (Pinus sylvestris L.) wood is one of the most popular timber export products. However, its low durability can reduce the potential and utilization of the wood. Chemical modification is one of the solutions to overcome this drawback. Chemical modification using non-biocide materials such as glycerol and citric acid was carried out to improve the inferior properties of wood. The study aimed to observe the microstructure and evaluate the surface characteristics of glycerol and citric acid-modified scots pine wood. Scots pine wood was modified using glycerol and citric acid with weight percent gain (WPG) values of 20% and 46%. Surface characteristics were measured, including surface roughness, surface free energy (SFE), wettability, and bonding quality. The results show that chemical modification using glycerol and citric acid resulted in the structure of the pine wood being more filled and denser. The modification could also reduce the roughness of the wood surface, resulting in decreased SFE value, increased contact angle, and decreased wettability on the wood surface. It might cause a decrease in the bonding quality because the wood did not have the strength to mechanically lock with the paint. Glycerol and citric acid modified-scots pine wood can be considered for exterior application. [ABSTRACT FROM AUTHOR]

The machinability of various grades of austempered ductile iron (ADI) has been investigated by using the surface roughness and the resultant chip formation as criteria. Grade 1 ADI, Grade 2 ADI, and Grade 3 ADI were commercially produced, commercially heat treated and machined under controlled conditions using coated carbide inserts with coolant in the laboratory. The milling performance of the various grades was compared to that of AISI 4340, which has a similar hardness to Grade 2 ADI. Grade 100-70-03 ductile iron was used as a reference material in the drilling study. The results of this study show that the surface finish of ADI and the resultant chip formation give quick indications if proper cutting parameters were used during machining of ADI. [ABSTRACT FROM AUTHOR]

Both visual and haptic softness perception have recently been shown to have multiple dimensions, such as deformability, granularity, fluidity, surface softness, and roughness. During haptic exploration, people adjust their hand motions (exploratory procedures, EPs) based on the material qualities of the object and the particular information they intend to acquire. Some of these EPs are also shown to be associated with perceived softness dimensions, for example, stroking a silk blouse or applying pressure to a pillow. Here, we aimed to investigate whether we can manipulate observers' judgments about softness attributes through exposure to videos of others performing various EPs on everyday soft materials. In two experiments, participants watched two videos of the same material: one with a corresponding EP and the other without correspondence; then, they judged these materials based on 12 softness-related adjectives (semantic differentiation method). The results of the second experiment suggested that when the EP is congruent with the dimension from which the material is chosen, the ratings for the adjectives from the same dimension are higher than the incongruent EP. This study provides evidence that participants can assess material properties from optic and mechanical cues without needing haptic signals. Additionally, our findings indicate that manipulating the hand motion can selectively facilitate material-related judgments. [ABSTRACT FROM AUTHOR]

Organogels are polymer networks extended by a liquid organic phase, offering a wide range of properties due to the many combinations of polymer networks, solvents, and shapes achievable through 3D printing. However, current printing methods limit solvent choice and composition, which in turn limits organogels' properties, applications, and potential for innovation. As a solution, a method for solvent‐independent printing of 3D organogel structures is presented. In this method, the printing step is decoupled from the choice of solvent, allowing access to the full spectrum of solvent diversity, thereby significantly expanding the range of achievable properties in organogel structures. With no changes to the polymer network, the 3D geometry, or the printing methodology itself, the choice of solvent alone is shown to have an enormous impact on organogel properties. As demonstrated, it can modulate the thermo‐mechanical properties of the organogels, both shifting and extending their thermal stability range to span from ‐30 to over 100 °C. The choice of solvent can also transition the organogels from highly adhesive to extremely slippery. Finally, the method also improves the surface smoothness of prints. Such advances have potential applications in soft robotics, actuators, and sensors, and represent a versatile approach to expanding the functionality of 3D‐printed organogels. [ABSTRACT FROM AUTHOR]

Fouling mitigation provides many challenges in process equipment, especially in heat exchangers. In this work, the fouling behaviors of two polymers are compared to 1.4301 stainless steel (SS) in calcium sulfate solutions. An experimental setup that allows to classify the materials quickly and under varying process conditions is used to determine the fouling behavior. Results are compared to a screening apparatus which can test up to three materials simultaneously. Finally, the cleaning behavior of all three materials is investigated. Results show that polyether ether ketone (PEEK) is superior to SS in mitigating fouling and is easier to clean; however, polyether ether ketone with 30 % talcum (TKT) is not. This is attributed to the surface roughness of the materials. [ABSTRACT FROM AUTHOR]

Systematic empirical relations were established for the nanosize-dependent surface roughness, $\varepsilon (D)$ ϵ (D) , dislocations, $N_D\lpar D \rpar$ N D (D) , and effective length to examine their effects on the temperature-dependent lattice thermal conductivity (LTC) within the framework of the Morelli-Callaway model for In0.53Ga0.47As alloy films with thicknesses ranging from 10 to 70 and 1400 nm, the latter representing the material's bulk state. The results were analyzed for film thicknesses of 2, 5, 200, and 500 nm, under the assumption that electrons and impurities are unaffected by nanosize, while a small alloy parameter significantly and sensitively alters the LTC curve in medium and high-temperature regions. According to these new findings, and considering phonon scattering processes, the LTC's temperature dependence is sufficiently reduced at the nanoscale and fits well with the available reported experimental findings. It was also discovered that the LTC's peak maximum value and its corresponding temperature are influenced by the film's dislocation concentration, surface roughness, and thickness. Unravelling the complex interplay between nanosize-dependent dislocation and surface roughness concentrations becomes critical for a thorough knowledge when examining the delicate nuances of LTC in In0.53Ga0.47As nanofilms. Finally, the Morelli-Callaway-based model has been modified to calculate LTC for nanofilms without fitting parameters, provided their related bulk state values are known. [ABSTRACT FROM AUTHOR]

The paper reports the study of surface roughness based opto-mechanical properties of Chlorobutyl (CIIR)/Natural Rubber (NR) 70/30 polymers filled with different contents of hybrid (CB/CN) using indigenously designed THz spectrophotometer between 1 and 2.0 THz range. The carbon black (CB) and Carbon nano powders were mixed between 20 and 2.0–7.5 Phr range in the chlorobutyl and natural rubber matrix for improvising their surface quality and mechanical strength. The physical and structural changes were ascertained in terms of transmission, refractive indices and absorption coefficients. The percentage of filler also influences the morphology and surface roughness quality of the rubber due to intercalation and measured in terms of surface roughness factor 'g' optical impedance 'z' and reflection coefficients between 0.1 and 2.0 THz range. The obtained values of optical impedance lie between 220.2 and 235.6 Ω range and were correlated with the mechanical strength of the rubber samples. It provides a new modality to understand the effect of fillers on the strength of rubber samples. [ABSTRACT FROM AUTHOR]

The present paper gives an overview of the recent modelling activities under NATO-STO AVT-349, focussed on the understanding and modelling of boundary layers for incompressible, high-Reynolds-number flows subject to non-equilibrium conditions such as strong pressure gradients, three-dimensionality, and surface roughness and heterogeneity. For this, we consider simpler cases where the above flow conditions are present separately or in a reduced number of combinations. First, we focus on the effect of roughness on the outer flow and the problems associated to its characterisation and prediction, with a particular emphasis on the conditions necessary for outer-layer similarity to hold. We then focus on how the presence of adverse and favourable pressure gradients affects the effect of roughness, and to what extent the figures used to quantify it are still useful under such conditions. We also consider the effect of surface heterogeneity, the shortcomings when modelling it and how these can be addressed. We then focus on the effect on the outer layer of pressure gradients and non-equilibrium conditions, to what extent similarity holds in those conditions, and how RANS models perform for such flows, identifying routes for their improvement to handle pressure gradients and non-equilibrium. We also discuss the use of data-driven and machine-aided methods in closure models. [ABSTRACT FROM AUTHOR]

This work deals with the regression models and multi-objective optimization method of the ultimate tensile strength, percentage of elongation, and average arithmetic surface roughness of butt friction stir welded AA2024-T3 aluminum alloy. Machining experiments were carried out according to the face centered central composite design of the response surface methodology. The effect of friction stir welding process parameters such as rotation speed, welding speed, and tool shoulder diameter on responses was investigated. Adequacies of the models are checked by the analysis of variance. The optimization of multiple responses was performed using the desirability analysis to achieve the higher ultimate tensile strength, maximum percentage of elongation, and minimum arithmetic surface roughness. From this investigation, it is found that the joints fabricated with the tool rotational speed of 752 rpm, welding speed of 100 mm/min, and tool shoulder diameter of 12.5 mm yield the maximum ultimate tensile strength and percentage of elongation, and minimum arithmetic surface roughness of 379.69 MPa, 10.22% MPa, and 6.66 HV, respectively. The effects of process parameters on the microhardness of welded zone were studied. The macrostructure, microstructure, and residual stress characterization of joints are examined. [ABSTRACT FROM AUTHOR]

In the realm of low-pressure wax injection molding, the cooling time refers to the period during which the molten wax inside the aluminum-filled epoxy resin rapid tool solidifies and cools to a temperature conducive to safe ejection without distortion. Consequently, ensuring efficient cooling is paramount for the mass production of injection-molded parts. However, cooling efficiency is affected by the different coolant media. The main purpose of this study is to investigate the effects of different coolant media on the cooling efficiency of aluminum-filled epoxy resin rapid tools with different surface roughness of cooling channels. It was found that the surface roughness of the inner wall in the low-pressure wax injection mold significantly influenced the cooling time of the molded product. In particular, a higher maximum roughness on the inner wall was associated with shorter cooling times for the injection-molded product. An aluminum-filled epoxy resin rapid tool with parallel cooling channels can reduce the cooling time of the injection-molded product by approximately 14.65%, 11.36%, 7.56%, and 16.50% using a coolant temperature of 15 °C compared with one equipped with a series of cooling channels. Taking the nanobubble coolant temperature of 15 °C as an example, an aluminum-filled epoxy resin rapid tool with parallel cooling channels can reduce the cooling time of the injection molded product by approximately 15.4% compared with one equipped with a series of cooling channels. Taking the vehicle coolant to cool aluminum-filled epoxy resin rapid tool as an example, the parallel cooling channel in the high-temperature aluminum-filled epoxy resin rapid tool demonstrates superior cooling efficiency compared to the series cooling channel, resulting in an average saving of about 49.05% in the cooling time of the aluminum-filled epoxy resin rapid tool. The results of this study have practical importance for industrial applications and support sustainable development goals 7, 9, 10, and 12. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced polymer (CFRP) and titanium alloy (Ti-6Al-4V) have excellent mechanical properties and have been widely used in aviation, aerospace, and other fields. Due to the different characteristics of CFRP/Ti-laminated materials, there are differences in their processing parameters and material removal methods. Cutter wear and hole defects are prone to occur. To study the cutting performance of cutters in laminated materials, this paper adopts the inclined angle milling method to process CFRP/Ti-laminated materials. The cutting performance of flat end milling cutter and circular arc milling cutter was compared and analyzed through designed variable parameter experiments. A study was conducted on the axial force, cutter wear mechanism, hole quality, and micro-morphology of the hole wall of two cutters under the inclined angle milling method. The results show that under different processing parameters, the difference in axial force between the two cutters is small in the carbon fiber layer. However, there is a significant difference in the titanium layer, with the axial force of the circular arc milling cutter being smaller than that of the flat end milling cutter. As the number of holes increases, the wear of the flat end milling cutter is serious, and the cutting edge is broken. The wear area gradually expands from the cutter tip to the surrounding cutting edge. The wear of the circular arc milling cutter is relatively light, and the cutting edge is damaged. As the wear at the arc transition becomes dull, the wear area gradually extends to the surrounding cutting edge. As the cutters wear out, many burrs and tear damage appear at the CFRP exit of the flat end milling cutter. Many high burrs appeared at the exit of Ti-6Al-4V. Comparing the micro-morphology of the hole wall of the two cutters at different fiber cutting angles, the quality of the hole wall of the flat end milling cutter is worse than that of the circular arc milling cutter. Due to the arc transition structure of the circular arc milling cutter, the hole wall has obvious groove scratches, resulting in a decrease in the quality of the Ti-6Al-4V hole wall. In addition, compared with the flat end milling cutter, the surface roughness of the hole of the circular arc milling cutter is better. [ABSTRACT FROM AUTHOR]

In the present global scenario, manufacturing industries are trying to make the process more sustainable by improving economic feasibility, machining efficiency, environment, and operator's safety as prescribed by ISO-14000 standards. The present study investigates the machining efficiency and sustainability analysis of the single wall carbon nano tube (SWCNT) mixed rotary electric discharge machining (EDM) process by utilizing waste vegetable oil (WVO) as a dielectric medium. Peak current, pulse on time, pulse off time, powder concentration, and tool rotation are taken as an input variable. The result reveals that SWCNT mixed rotary EDM utilizing WVO as a dielectric fluid exhibit 119.91% higher material removal rate (MRR) and 61.23% lower surface roughness (SR) as compared to the EDM process using EDM oil as a dielectric medium. Further, due to the superior thermo-physical properties of WVO, the proposed dielectric shows better surface morphology, lower recast layer thickness, better wear resistance, and low micro-hardness of machined surface as compared to EDM oil. Finally, the sustainability index analysis result concludes that WVO could be a better replacement of hydrocarbon-based oils in the EDM industry to make the process more sustainable in terms of cost, performance, ecological balance, and operator's safety. [ABSTRACT FROM AUTHOR]

Magnesium alloys have attracted significant research attention due to their impressive mechanical properties, such as machinability, a high strength-to-weight ratio, and low density compared to aluminium and steel. Due to the above properties, Mg alloys have a wide range of applications in the field of biomedical applications such as vascular stents and fixatives, aircraft fuselage, micro-electro-mechanical systems (MEMS), and automotive industries. The current work focused on the performance of uncoated and AlTiN-coated micro end-mill cutters having a diameter of 0.5 mm and two flutes in the development of machined surface morphology of AZ31B magnesium alloy and the analysis of cutting forces under the varying spindle speeds of 20,000, 40,000, and 65,000 rpm and feeds of 0.5, 2, and 4 µm/tooth. In general, the results indicated that the uncoated tools consistently resulted in lower values of cutting forces (Fx, Fy and Fz), and surface roughness than with AlTiN-coated tools under all conditions of machining. This could be attributed to the increase in cutting edge radius due to the deposition of the coating resulting in rubbing and ploughing to become predominant. Adhesion of work materials during machining using the AlTiN-coated tool was explained by the chemical affinity of aluminium of the coating towards Mg alloys. After careful analysis of the results, relatively low cutting forces were noticed, and due to the absence of tool wear, there was no significant variation in surface roughness with an increase in cutting length up to 60 mm. [ABSTRACT FROM AUTHOR]

Large shaft grinding processes are required to generate multiple quality indices with good consistency, such as profile dimension accuracy, surface roughness, and optical glossiness. Generating profiles for large shafts in the grinding process requires the grinding wheels to move transversely under the desired path, which includes rough grinding, semi-finish grinding, finish grinding, and spark-out grinding stages, and each grinding stage needs to go through multiple passes under different process parameters. Therefore, the design and selection of process parameters for each grinding stage is always challenging to meet both quality and efficiency requirements. In this study, a multi-objective optimization method for transverse profile grinding processes of large shafts is developed. In the proposed method, multiple grinding quality indices and grinding efficiency are taken as optimization objectives, and grinding surface quality, grinding depth, and grinder machining performance are taken as constraints. By utilizing the dynamic factor improvement strategy and the adaptive grid density improvement strategy, an improved particle swarm algorithm is developed to optimize the grinding process parameters. The grinding dimensional error compensation method and the surface quality consistency control method are integrated into the improved particle swarm algorithm to realize the accurate prediction of grinding dimensional accuracy and surface quality. Based on the proposed method, the optimized grinding process can be obtained, and the effectiveness of the method is verified by grinding experiments. [ABSTRACT FROM AUTHOR]

Vibration-assisted micro-milling has emerged as a promising technique in vibration-assisted machining, aiming to enhance machining quality by applying small-amplitude high-frequency vibrations to the workpiece during micro-milling operations. This paper presents a novel design of a piezo actuator-based non-resonant type workpiece vibratory system specifically designed for 2D vibration-assisted micro-milling application. The developed system is experimentally evaluated by generating 2D vibrations, considering each axis' cross-coupling and hysteresis displacements, at various actuation frequencies ranging from 100 to 600 Hz. The application of the proposed setup focuses on the micro-milling of slots on an Aluminum 6061 and Titanium grade-5 workpiece samples, utilizing 2D sinusoidal out-of-phase vibrations along x and y directions with a peak-to-valley amplitude of 10 µm. The cutting force data is collected and recorded by a tool force dynamometer, and the root mean square value of the cutting force is used as a parameter to compare conventional micro-milling with vibration-assisted micro-milling processes. In addition, the study compares the average surface roughness of the milled slots when using vibration assistance and without it. The experimental results demonstrate a significant decrease in cutting force and an improvement in the average surface roughness of the milled slot when implementing 2D vibration-assisted micro-milling. These findings highlight the significance of the design, characterization, applicability, and suitability of the proposed non-resonant workpiece vibratory system in the field of vibration-assisted micro-milling process. [ABSTRACT FROM AUTHOR]

To improve the surface roughness (Ra) of the connecting rod journals of crankshafts and reduce polishing time for abrasive belt polishing machines, a method for optimizing the polishing process parameters for connecting rod journals is proposed, combining BP neural network and NSGA-II algorithm. Initially, factors affecting the surface roughness are screened, and in consideration of practical production requirements, a five-factor four-level orthogonal experiment is designed. A BP neural network is then used to establish a nonlinear mapping relationship between the polishing process parameters and the surface roughness of the connecting rod journals. The predicted results from the BP neural network are used as fitness values, and the NSGA-II algorithm is employed to obtain the Pareto frontier optimal solution set and the corresponding combination of polishing process parameters.According to the optimization results, the process parameters of the abrasive belt polishing machine model are modified as follows: polishing arm cylinder pressure of 0.8 MPa, rotational axis output speed of 140 rpm, abrasive belt model B with grit size 800#, Coolant type concentration of 9%, and polishing time of 20 s. In comparison to the initial scheme parameters of the abrasive belt polishing machine, this combination of parameters resulted in a 25.2% increase in surface roughness at the connecting rod journal and saved 20% of the polishing time. Through the process parameter optimization method in this paper, it will contribute to improving the production performance of the crankshaft abrasive belt polishing machine, effectively enhancing the surface roughness at the processed connecting rod journal and saving polishing time. [ABSTRACT FROM AUTHOR]

For conventional optical manufacturing combining ion beam figuring (IBF) and abrasive finishing, it is difficult to achieve an atomic-scale smooth surface with microroughness below 0.1 nm. Because the abrasives inevitably damage the surface, and the damages are exposed during ion sputtering. To solve this problem, plasma-induced atom migration manufacturing (PAMM) and IBF were combined in this study. PAMM is a damage recovery process based on atom migration effect. In this study, PAMM was employed to recover the subsurface damage and then the damage-less surface was further processed by IBF to remove the form error as well as reduce the roughness to atomic level. Full spatial frequency error convergence was achieved via the combined process of PAMM and IBF. A good surface accuracy of 3.89 nm RMS and an atomically smooth surface with a roughness of 0.044 nm were obtained. The less damage characteristic of the hybrid process was also demonstrated by buffered oxide etching (BOE). This study proposed and verified a hybrid process combining PAMM for damage recovery and IBF for figuring and atomic-scale smoothing, which provided a novel process strategy for manufacturing ultra-precision optics with high quality. • Plasma-induced atom migration (PAMM) and ion beam figuring (IBF) were combined for fused silica. • Subsurface damage evolved into micro pits during IBF, which hindered further roughness reduction. • PAMM recovered the subsurface damage, then IBF removed the form error as well as reduced the roughness to atomic level. • PAMM-IBF process realized full spatial frequency convergence, with RMS 3.89 nm and Sa 0.044 nm in LSF and HSF error. [ABSTRACT FROM AUTHOR]

This study sheds light on unsteady heat and fluid flow problems over stretching and shrinking surfaces, enriching our understanding of these complex phenomena. We derive two mathematical models using a rigorous approach. The first model aligns with the model commonly employed by researchers in this field, but its steady-state solution remains trivial. The second model, introduced in this work, demonstrably captures the physically relevant steady-state solutions well-studied in the literature. Notably, we introduce new similarity solutions for the temperature field specifically within the first model. We further demonstrate that a uniform wall temperature condition leads to the optimal heat transfer rate. While similarity solutions can be derived for specific cases with the second model, nonsimilar solutions may be necessary for more general scenarios. We discuss the implications of our analysis for stagnation-point flow and non-Newtonian viscoelastic fluid flow problems, illuminating future research directions in the open literature. [ABSTRACT FROM AUTHOR]

In this investigation, we explore the profound impact of adiabatic partitions on heat transport within a square Rayleigh-Bénard (RB) convection enclosure characterized by surface roughness on the lower hot and upper cold plates. The surface irregularities take the form of a rectangular base and a triangular apex. Our study employs two-dimensional direct numerical simulations spanning the Rayleigh number (Ra) range of -106-108 and a Prandtl number (Pr) of 1. Adiabatic partitions, strategically positioned between successive roughness, serve as the focal point of our exploration. Remarkably, our findings reveal a substantial enhancement in heat transport with the introduction of a partition board between consecutive roughness elements. As we escalate the number of partitions from one to four, the heat flux experiences a notable augmentation, reaching 2.3 times that of the classical square RB configuration. This enhancement is attributed to the breakdown of large-scale rolls into multiple rolls, a phenomenon intensified by the increased partition height. Further intriguing observations unfold as we investigate the interplay of surface roughness and partitions. Configurations featuring roughness with partitions exhibit an impressive 2.7 times heat flux enhancement compared to the classical square RB setup. The complex interplay of heat transport improvement is closely connected to optimizing the distance between the conduction plate and the partition. Through meticulous analysis, we identify that the optimal gap facilitates heightened local velocity, effectively thinning the thermal boundary layer and consequently augmenting the overall heat flux. In essence, our study sheds light on the synergistic effects of adiabatic partitions and surface roughness in the context of RB convection. The observed enhancements in heat transport underscore the potential for tailored design strategies involving partitions and surface modifications to optimize thermal performance in diverse applications. [ABSTRACT FROM AUTHOR]

Micro-Electromechanical-Relay (MER) has widely achieved application in the field of engineering thanks to the excellent features and ever-growing interest in microelectronic products. However, the adhesion phenomenon between gold-sputtered contact pairs in MER usually brings about operating failure of normally closed contacts limiting the reliability level of MER. In this paper, various contact combinations between electrical contact pairs are assembled to simulate real contact conditions, and associated failure type is built by taking advantage of mechanical adhesion theory to reveal failure mechanism about cold adhesion. It is found that the adhesion force is correlated closely with the surface roughness of contact pairs. The specific contact combination is a significant effective strategy to reduce the adhesion failure between electrical contacts. [ABSTRACT FROM AUTHOR]

[Objective] The aims of this study are to examine the relationship between gully slope slumping erosion and topographic factors, and to provide a theoretical reference for the mechanism of gully slope slumping erosion and erosion disaster monitoring in bare sandstone area. Methods Based on in-situ monitoring and 3D laser scanning technology, the characteristics of slumping erosion and the variation of topographic factors were analyzed. [Results (1) The amount of slumping erosion was significantly correlated with temperature and wind speed, and the correlation coefficients were 0.867 and 0.917. (2) The topographic factor values showed an increasing trend in general, the surface roughness and surface undulations fluctuated more obviously on the slope, and the fluctuations changed slowly in the middle and lower slopes, and the gully density had no obvious regularity. (3) The amount of slumping erosion was significantly correlated with surface roughness and surface fluctuation, and the relationship was polynomial regression, there was no significant correlation with gully density. There was a certain correlation among the topographic factors, and the surface roughness and surface undulations showed a significant positive correlation, and the correlation coefficient was 0.89. [Conclusion] The erosion amount of gully slope in bare sandstone area can be characterized by the numerical fluctuation of surface roughness and surface fluctuation [ABSTRACT FROM AUTHOR]

[Display omitted] "Polymer-in-ceramic" (PIC) electrolytes are widely investigated for all-solid-state batteries (ASSBs) due to their good thermal stability and mechanical performance. However, achieving fast and diversified lithium-ion transport inside the PIC electrolyte and uniform Li+ deposition at the electrolyte/Li anode interface simultaneously remains a challenge. Besides, the effect of ceramic particle size on Li+ transport and Li anodic compatibility is still unclear, which is essential for revealing the enhanced mechanism of the performance for PIC electrolytes. Herein, PIC with moderate ceramic size and contents are prepared and studied to strike a balance between ionic conductivity and anodic compatibility. Through moderate filler-filler interfacial impedance and appropriate surface roughness, a particle size of 17 μm is optimized to facilitate homogeneous Li+ flux on anode and enhance Li+ conductivity of the electrolyte. The PIC electrolyte with ceramic particle size of 17 μm achieves a high lithium ion transference number (0.74) and an ionic conductivity of 4.11 × 10−4 S cm−1 at 60 °C. The Li/PIC/Li symmetric cell can stably cycle for 2800 h at 0.2 mA cm−2 with 0.2 mAh cm−2. Additionally, the Li/PIC/LiFePO 4 cell also delivers a superior cycling performance at 0.5C, a high capacity retention of 93.28% after 100 cycles and 83.17% after 200 cycles, respectively. [ABSTRACT FROM AUTHOR]

Vat photopolymerization (VPP) in ceramic additive manufacturing (CAM) faces challenges due to high viscosity from ceramic powder loading, necessitating interruptive recoating steps. Ceramic particles also attenuate and divert irradiated light, causing reduced cure depth and over-curing, leading to slow print, weak interlay adhesion, and dimensional errors. This study introduces photo inhibition-aided CAM (PinCAM) using dual-wavelength digital light processing to mitigate these issues. PinCAM employs two optical masks for initiation and inhibition at different wavelengths. While previous research focused on polymers, this work evaluates inhibition's effects in suspension-based VPP-CAM. Modeling and experiments examine inhibition and curing characteristics, print speed, dimensional accuracy, surface roughness, and microstructure. Preliminary results suggest that photoinhibition has the potential to enhance geometrical and surface properties as well as particle distribution homogeneity of green ceramic components without significantly compromising print speed. Understanding inhibition's impact will aid further research in PinCAM optimization for rapid and precise ceramic manufacturing. • First systematic study on two-wavelength Photoinhibition aided Ceramic AM (PinCAM). • Modeling and characterization of inhibition and curing characteristics in PinCAM. • Pilot study on curing light and inhibition ratio effects in PinCAM speed & product. • Optimal inhibition enhances geometry, surface, density, & homogeneity of green part. • Theoretical basis & methods to establish PinCAM for advanced ceramic manufacturing. [ABSTRACT FROM AUTHOR]

Background: The experimental detection of small and large strains requires special approaches of full-field measurement techniques and their evaluation on 3D curved surfaces of components. Objectives: Since classical digital image correlation methods have difficulties with the application of paints in some applications, one aim is to use a method in which the surface roughness is used to apply the strain calculation. Methods: In this paper, 2D digital image correlation is applied to 2D intensity maps extracted from a coherence scanning interferometer together with height information. Height information are used to reconstruct the 3D motion of tracked material points. Surface interpolation and strain calculation are performed using globally formulated radial basis functions. Results: The entire procedure leads to an appropriate technique for determining the in-plane strains in curved surfaces of parts, whereas the expected accuracy for various levels of the radial basis functions are discussed in detail. Conclusions: Particularly, coherence scanning interferometry yields highly accurate height information. To smooth the surface motion, it turns out that in particular a regression analysis is required, where we apply radial basis functions with various approximation levels. This is an alternative procedure for surface strain determination. [ABSTRACT FROM AUTHOR]

ZrO 2 ceramics were fabricated by slurry-based material extrusion along the Z-printing direction, and the anisotropic shrinkage rate, surface roughness, flexural and compressive strength of ZrO 2 ceramics sintered at different temperatures were investigated and discussed in this manuscript. The results indicated that the sintered ZrO 2 ceramic samples possessed anisotropic sintering shrinkage rates in different directions and roughness on different surfaces, where the shrinkage rates in the Z and X directions were relatively larger, and the roughness on the YZ surface was relatively lower, which can be explained using varying stresses induced by different sintering temperatures and gravity force during printing and sintering. When loaded along the F Z direction, the ceramic samples exhibited relatively higher flexural and compressive strength, and the main reason for anisotropic strength was that the bonding layers along the Z-printing direction were tighter, while weak connections and shear deformation between extruded filaments led to a reduction in strength. When sintered at 1450 °C for 2 h, the ceramic samples exhibited the minimum anisotropic behavior and superior comprehensive properties, and the corresponding anisotropic factors for shrinkage rate were 0.96 (δ Y / δ X) and 0.97 (δ X / δ Z), for surface roughness was 0.94, for flexural and compressive strength were 0.87 and 0.63, respectively. [ABSTRACT FROM AUTHOR]

Mountainous regions are often characterized by the presence of V-shaped gullies, necessitating the construction of retaining structures to support the embankments spanning across these gullies. The gully topography renders conventional two-dimensional soil pressure calculation theory unable to meet the stability requirements for the design of retaining walls (RWs) in mountainous gullies. To address this issue, the sliding bodies of V-shaped gully retaining walls have been identified as high-wall type and low-wall type, and the spatial earth pressure of V-shaped RWs has been determined using the horizontal differential layer method. Combined with numerical simulation, a systematic parametric study is conducted to reveal the impact of the fill-soil internal friction angle, wall–soil contact surface roughness, wall height-to-width ratio, and valley side-slope angle on the active earth pressure acting on the wall. The magnitude of internal friction angle of the fill and the side-bank angle significantly influence the horizontal earth pressure. However, for RWs with finite length along their longitudinal direction, the active earth pressure value at the wall ends is significantly lower than values computed under two-dimensional plane-strain conditions. Moreover, the resultant active force point is located in the range of H/3−H/2 from the wall bottom, where H = wall height, which shows that considering three-dimensional effects is significant. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the surface roughness and color stability of a single-shade composite resin after thermal cycling with different finishing and polishing systems. Methods: A total of 91 specimens were prepared with standard molds using a single-shade resin composite Omnichroma. The specimens were randomly separated into seven groups: Control (Mylar strip only), grit (600 grit SiC abrasive paper), OneGloss, Clearfil Twist Dia, Sof-Lex Diamond Polishing System, EVE Diacomp Plus Twist, and OptiDisc. The top surface of each specimen was polished per the manufacturers' directions. After initial measurements, 10,000 and 50,000 thermal cycles were performed. After each thermal cycling, the measurements were retaken. A generalized linear model analysis was used to compare the values, and multiple comparisons were performed with the Bonferroni correction. Results: Different finishing and polishing systems and thermal cycling significantly affected the surface roughness and color change of the single-shade composite resin (P< 0.001). The smoothest surfaces were obtained with the Sof-Lex Diamond Polishing System, while the group polished with Clearfil Twist Dia showed the least color change. [ABSTRACT FROM AUTHOR]

Dispersive soil slopes are widely distributed in Northeast China. To analyze the failure caused by such slopes under various rainfall conditions, section K27 of the road-cutting slope of the Sui-Da Expressway in Heilongjiang Province, China, is considered an example. A 3D slope model was created using the similarity theory and visualized through close-range photogrammetry in a self-made model box. Six model tests were conducted under varying rainfall conditions to investigate the failure modes of dispersive soil slopes. Test results revealed that dispersive soil slopes are subject to two types of failure depending on the rainfall intensity. Slope erosion was divided into three stages by surface random roughness (SRR): initial erosion, constant velocity erosion, and accelerated erosion. Similarity theory suggests that the slope enters the accelerated erosion stage in the actual project when the SRR reaches around 31.95–46.5 cm. Furthermore, the reciprocal of the SRR change rate during the accelerated erosion stage exhibits a linear correlation with time. The time of the slope's complete failure can be estimated when the reciprocal of the SRR change rate is 0 min/cm. The research findings are significant for comprehending the failure process of dispersive soil slopes. [ABSTRACT FROM AUTHOR]

Adjustable-ring-mode (ARM) laser welding displays great potential for improving the stability of the molten pool and the weld quality of aluminum alloys through the coaxial attachment of a large-sized ring-beam spot. In this paper, the author embarked on a systematic study on the impact of varied core powers, ring powers, and core/ring power ratios on the weld morphology, microstructure, and mechanical properties of Al-Mg alloy during the laser welding process with ARM. The results showed that the core power led to higher depth of penetration, and the superheating of the molten pool it created caused grain coarsening and reduced properties. The ring beam effectively decreased weld spatter and enhanced the surface roughness of the weld. Furthermore, the ring beam was more likely to obtain a wider columnar crystal zone and a more homogeneous grain size distribution. The welded joints possessed higher tensile strength values when ring beam power was increased from 1.5 to 2 kW due to the improvement of surface flatness and porosity defects by the ring beam. • The effects of a single beam and different core/ring power ratios on the laser welding of Al-Mg alloys were investigated. • Additional ring beams effectively improved weld surface quality, which is conducive to the increase of tensile strength. • The ring beam could significantly change the width of the columnar crystal zone. • A core/ring power ratio of 1.5 resulted in a more uniform microstructure and performance distribution. [ABSTRACT FROM AUTHOR]

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]

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]

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]

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]

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]

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]