Search Results (1,772)

Electropolishing is an essential process for the surface treatment of metallic materials. To determine the appropriate replacement timing of electropolishing solutions for their efficient use and improved productivity, it is important to periodically analyze the amounts of dissolved metals in the solutions. However, these solutions are typically highly corrosive, and on-site analytical techniques that can be easily applied at production sites have not yet been established. In this study, we demonstrated microvolume liquid analysis using low-energy laser-induced breakdown spectroscopy (LIBS) combined with a porous silicon substrate fabricated by metal-assisted etching (metal-assisted chemical etching) and a non-contact gas-blowing pretreatment. In the analysis of electropolishing solutions used for niobium superconducting cavities and stainless steel products, emission lines of niobium and of iron and chromium were successfully detected after blowing the respective microdroplet samples on porous silicon, and linear correlations were observed between the spectral line intensity and the polished amounts. The present results provide a basis for future on-site application of LIBS to highly corrosive electropolishing solutions in the metal finishing industry. Full article

This study examines in situ induction-heating thermal field assistance during laser cladding of Stellite 6 on 17-4PH stainless steel. Single-layer, multi-track coatings (~2.3 mm) were produced at induction powers of 0, 300, 600, and 900 W while keeping laser parameters constant. Surface morphology, phase constituents, and microstructures were characterized by LSCM, OM, XRD, SEM, EDS, and EBSD, and nanoscale features were probed by TEM for the 600 W condition; microhardness and coating-only tensile properties were evaluated. Thermal assistance improved surface finish (minimum Sa = 16.67 μm at 600 W) and suppressed hot cracking. XRD/EBSD revealed a γ-Co matrix with interdendritic carbides and an increased ε-Co fraction under thermal assistance; TEM further showed stacking-fault lamellae and a distinct FCC/HCP interface, supporting a fault-assisted, diffusionless γ → ε transformation. Increasing induction power coarsened the microstructure (larger D_E and SDAS), decreasing hardness from 537.1 to 461.5 HV_0.1 and lowering yield/ultimate strengths from 1046 MPa and 1512 MPa to 849 MPa and 1423 MPa, while elongation increased from 4.37% to 6.27%. Considering crack-free valve hardfacing with acceptable strength loss and improved ductility, 600 W provides the best overall performance. Full article

Natural fabrics such as cotton and silk have been widely used due to their excellent properties, but their tendency to wrinkle limits their value. Traditional anti-wrinkle finishing agents suffer from issues like formaldehyde release and performance imbalance. This paper reviews the advances in anti-wrinkle finishing of cotton and silk fabrics, analyzing from the perspectives of environmentally friendly finishing agents, physical properties balancing, sustainable anti-wrinkle finishing, and synchronized multi-functionality. Current research have developed various environmentally friendly formaldehyde-free finishing agents, such as carboxylated polyaldehyde sucrose and α-lipoic acid, through strategies including natural product modification and organic–inorganic hybridization. The application of these agents can enable fabrics to achieve a balance between wrinkle resistance, mechanical properties, hydrophilicity, and resistance to yellowing properties. Simultaneously, they also overcome the limitations of traditional processes, endow fabric with integrated application of wrinkle resistance alongside functions such as dyeing, flame retardancy, and antibacterial properties. Moreover, optimization methods such as response surface methodology (RSM) have facilitated the precise regulation of process parameters. Future research should continue to focus on greenization, high performance, and multi-functional coordination, deepen molecular design and process optimization, and provide support for the sustainable development of the textile industry. Full article

This study investigates the influence of hybrid additives and cutting parameters on the surface roughness (R_a) of drilled Glass Fiber Reinforced Polymer (GFRP) composites. Nine composite panels were fabricated with varying concentrations of wax (0%, 1%, 2%) and graphene (0%, 0.25%, 2%). Drilling experiments were conducted on a CNC milling machine using a range of cutting velocities (50–200 m/min) and feeds (0.02–0.08 mm/rev), and the resulting surface roughness was measured using a profilometer. The results demonstrate that cutting velocity is the most dominant parameter, contributing to 69% of the variability in surface roughness, followed by feed (16%). The incorporation of additives, specifically 1 wt% wax and 0.25 wt% graphene, produced a synergistic effect, yielding the lowest average surface roughness (≈2.9 µm) and the most stable machining process. Higher cutting velocities increased roughness due to thermal effects, while increasing feeds improved surface finish by reducing frictional heating. The findings indicate that an optimal combination of moderate additive concentrations and controlled machining parameters can significantly enhance the surface integrity and process repeatability in the drilling of GFRP composites. Full article

To address the bottleneck issues of traditional ultrasonic polishing—such as unclear material removal mechanisms for ductile metals and difficulties in controlling machining outcomes—this paper employs a combined approach of computational fluid dynamics (CFD) simulation and non-contact fixed-point polishing experiments to systematically reveal the intrinsic relationship between the dynamic characteristics of the polishing flow field and the evolution of the material surface. Numerical simulations demonstrate that the cavitation effect significantly regulates the flow field structure: it not only confines the minimum pressure near the saturated vapor pressure but also markedly reduces the pressure peak while concurrently causing an overall decrease in flow velocity, forming a strongly coupled multi-parameter system of pressure, cavitation, and flow velocity. Experimental results indicate a clear spatial differentiation in the material removal mechanism: the central region is dominated by cavitation erosion, resulting in numerous pits and a 33.6% increase in residual compressive stress; the edge region is primarily governed by fluid-mechanical scraping, effectively improving surface finish and increasing residual stress by 22.3%; the transition zone, influenced by synergistic mechanisms, shows the smallest stress increase (19.7%). The enhancement of residual compressive stress can significantly improve the fatigue resistance of materials and prolong their fatigue life. This study comprehensively elucidates the multi-mechanism synergistic material removal process involving “cavitation impact, mechanical scraping, and fatigue spallation” in ultrasonic polishing, providing a key theoretical basis and process optimization direction for sub-micrometer ultra-precision machining. Full article

Background: Nickel–titanium (NiTi) endodontic instruments have undergone significant improvements in heat treatment processing and geometric design, aimed at enhancing flexibility, cutting efficiency, and fatigue strength. Reciprocating motion was introduced to increase cyclic fatigue resistance, which remains the predominant mode of failure in NiTi endodontic file systems. Although these instruments are widely used in both clinical practice and research, few comparative studies have integrated geometric, metallurgical and mechanical evaluations of the most commonly used reciprocating systems. Methods: In the present study, four single-file reciprocating NiTi systems (Reciproc Blue, WaveOne Gold, EdgeOne Fire, and Easy-File Flex) were evaluated for their geometric design, metallurgical composition, and cyclic fatigue strength. Stereomicroscopy and scanning electron microscopy were employed to assess active blade length, spiral configuration, and surface finish, while elemental composition and phase transformation temperatures were analyzed using energy-dispersive X-ray spectroscopy and differential scanning calorimetry. Ten instruments from each group were tested for cyclic fatigue using a standardized curved stainless-steel canal at room temperature, and the time to fracture was recorded. Fatigue data were statistically analyzed using Mood’s median test, with significance set at p < 0.05. Results: Reciproc Blue exhibited the longest active blade length, highest spiral density, and superior surface finish. R-phase start and finish temperatures were highest in WaveOne Gold and lowest in Easy-File Flex. Reciproc Blue demonstrated the higher cyclic fatigue strength, whereas Easy-File Flex showed the lowest. Conclusions: These findings suggest that the metallurgical and geometric characteristics of the Reciproc Blue file significantly enhance its strength to cyclic fatigue compared with the other instruments evaluated. Full article

Abrasive water jet machining (AWJM) is a non-traditional machining process that is increasingly employed for shaping hard-to-machine materials, particularly titanium (Ti)-based alloys such as Ti-6Al-4V. Owing to its non-thermal nature, AWJM enables effective material removal while minimising metallurgical damage and preserving subsurface integrity. The process performance is governed by several interacting parameters, including jet pressure, abrasive type and flow rate, nozzle traverse speed, stand-off distance, jet incident angle, and nozzle design. These parameters collectively influence key output responses such as the material removal rate (MRR), surface roughness, kerf geometry, and subsurface quality. The existing studies consistently report that the jet pressure and abrasive flow rate are directly proportional to MRR, whereas the nozzle traverse speed and stand-off distance exhibit inverse relationships. Nozzle geometry plays a critical role in jet acceleration and abrasive entrainment through the Venturi effect, thereby affecting the cutting efficiency and surface finish. Optimisation studies based on the design of the experiments identify jet pressure and traverse speed as the most significant parameters controlling the surface quality in the AWJM of titanium alloys. Recent research demonstrates the effectiveness of artificial neural networks (ANNs) for process modelling and optimisation of AWJM of Ti-6Al-4V, achieving high predictive accuracy with limited experimental data. This review highlights research gaps in artificial intelligence-based fatigue behaviour prediction, computational fluid dynamics analysis of nozzle wear mechanisms and jet behaviour, and the development of hybrid AWJM systems for enhanced machining performance. Full article

The high performance of optical components is contingent upon the quality of their optical surfaces, thereby imposing elevated standards on the methodologies employed for their fabrication. This study involved experimental research on freeform optical surface elements of polymethyl methacrylate with nano-surface roughness. In this study, the effects of machining parameters of ultra-precision slow tool servo turning on the surface roughness of different types of areas of freeform optical surfaces in the finishing stage were analysed. Based on the analysis of ultra-precision turning test results for freeform optical surfaces, a novel evaluation method for surface quality is proposed to assess the overall uniformity of surface quality across the entire freeform optical surface. Building upon this proposed evaluation method for overall surface quality uniformity, the processing method of high-quality freeform optical surfaces is studied. The results show that in the finishing stage, the radial feed rate exerts the greatest influence on the surface roughness of the freeform optical surface, especially the surface roughness of the concave surface area. This will exacerbate the surface quality inhomogeneity of the freeform optical surface. Based on the analysis results, optimal machining parameters were selected for processing trials. Concurrently, additional machining tests were conducted to further validate the influence of radial feed rate. Ultimately, a nano-scale PMMA freeform optical surface with uniform overall surface quality was achieved. The variation in surface roughness in different regions of the optical freeform is regulated to stabilise within 2 nm on the surface of polymethyl methacrylate. The overall uniformity of surface quality across the entire freeform optical surface was maintained at a high level. Full article

Gears, as critical power-transmission components in most power equipment, have a particularly urgent need for in situ inspection systems. Traditional gear inspection methods rely on contact inspection instruments, which are not only time-consuming, but also potentially damage the gear surface due to contact. This study delves into the detection requirements in the gear manufacturing process and establishes a rapid, non-contact detection mechanism and model using a CHCS. This model employs a CHCS to achieve high-speed, non-contact measurement on various surfaces with extremely high accuracy, enabling real-time monitoring of production process details, thereby improving production efficiency and ensuring product quality. Through actual inspection and comparison with a standard involute spur gear tooth profile model, this study implements a complete inspection system in a prototype. The results of gear inspection using a CHCS with an accuracy of 1 μm showed that the interquartile range of qualified gears under test (GUTs) was within 2.5 μm, and the beard line value was within 10 μm. The experiment demonstrated a layout equipped with a CHCS where the rotating axis represents the hobbing machine spindle. This method can be completed without moving the gear, enabling subsequent finishing processes. Full article

As LED devices continue to advance toward miniaturization and higher power density, heat dissipation has become a critical factor constraining their reliability and service life. Molybdenum is widely employed as a substrate material in LED devices owing to its high thermal conductivity and low coefficient of thermal expansion. However, substrate applications impose stringent requirements on surface finish, flatness, and low-damage processing. Chemical mechanical polishing (CMP) can effectively balance global and local flatness and serves as the final step in producing high-quality molybdenum substrate surfaces. To enable efficient and precise processing of molybdenum substrates, this study adopts an orthogonal experimental design for double-sided CMP to systematically investigate the effects of polishing pressure, polishing slurry pH, additives in the polishing slurry, and abrasive particle size on the material removal rate (MRR) and surface roughness (Sa). An optimal parameter combination was identified via weight-matrix optimization: a polishing pressure of 115 kPa, pH 11, H₂O₂ (0.5%) and glycine (5 mg/L) as additives, and an abrasive particle size of 0.6 μm. Under these conditions, the MRR reached 80 nm·min⁻¹ and Sa decreased to 1.1 nm, yielding a smooth, mirror-like surface. The results indicate that multi-factor synergistic optimization can substantially enhance both surface quality and processing efficiency in double-sided CMP of molybdenum substrates, providing a process basis for applications in high-power LED devices. Full article

This study builds on previous research into the surface modification of beech wood with polyethyleneimine (PEI) prior to finishing it with a waterborne coating. Poly(diallyldimethylammonium chloride) (PDADMAC) is introduced as an alternative cationic polyelectrolyte for the pretreatment of beech wood surfaces. Wood samples were treated with aqueous 1% PDADMAC solutions of low (LMW—8000 g mol⁻¹) and high (HMW—100,000–200,000 g mol⁻¹) molecular weights, with or without NaCl addition. The effects of the treatments on wood surface chemistry, wettability, surface energy, water absorption, coating penetration, coating adhesion strength, and surface roughness of coated wood were analysed using FTIR, fluorescence microscopy, SEM/EDS, and standardised tests commonly used in wood surface finishing. The results showed that polyelectrolyte pretreatment modified the surface properties of wood, reducing water absorption and surface roughness without significantly affecting coating adhesion strength. PDADMAC formed a more uniform surface layer of wood with limited coating penetration, and NaCl addition improved wood surface smoothness (reducing surface roughness parameters of coated wood by 23%–29%, in samples treated with PDADMAC LMW with 0.01 M NaCl). These findings confirm that cationic polyelectrolyte pretreatment enhances the compatibility and performance of waterborne coatings, offering an environmentally friendly approach to improving wood–waterborne coating interactions. Full article

Reversed-phase high-performance liquid chromatography (RP-HPLC) remains one of the most widely applied analytical techniques in the development and quality control testing of finished pharmaceutical products. The combination of gradient chromatographic methods with diode-array detection (DAD) enhances selectivity, ensuring accuracy and reliability when testing drugs with diverse chemical properties in a single dosage form (i.e., fixed-dose combination (FDC) products). In this study, an RP-DAD-HPLC method was developed for the quantitative analysis of clofazimine (CFZ) and pyrazinamide (PZA) for inclusion in an FDC topical drug delivery system. Chromatographic separation was achieved using a C18 column (4.6 mm × 150 mm, 5 µm particle size) with gradient elution at 1 mL/min, employing 0.1% aqueous formic acid and acetonitrile (mobile phases). PZA and CFZ were detected at 254 nm and 284 nm, respectively. The method was validated in accordance with ICH Q2 guidelines, assessing specificity (considering interference from solvents, product matrix, and degradation products), linearity (7.8–500.0 µg/mL, r² = 0.9999), system repeatability (%RSD ≤ 2.7%), and intermediate precision (25–500 µg/mL, %RSD ≤ 0.85%). Method robustness was evaluated using a three-level Box–Behnken design (BBD) with response surface methodology (RSM) to assess the effects of variations in detection wavelength, mobile phase flow rate, and column temperature. Full article

This study examined the association between biofilm growth and surface properties of 3D printed, milled, and conventional materials used for manufacturing fixed dental prostheses. Disc-shaped specimens were produced and finished from five 3D-printing resins (VarseoSmile Crown plus [VSC], NextDent C&B MFH [ND], VarseoSmile Temp [VST], Temp PRINT [TP], P Pro Crown & Bridge [P]), two polymer milling blocks (composite: TetricCAD [TC], PMMA: TelioCAD [TEL]), two conventional polymer materials (Tetric EvoCeram [TEC], Protemp 4 [PT]), and zirconia (ZR). Surface roughness (R_a), wettability, interfacial tension (IFT) and surface topography were examined. Three-day biofilms were grown on the specimens using A. naeslundii, S. gordonii, S. mutans, S. oralis, and S. sanguinis in a multi-species suspension. Biofilms were quantified by crystal violet staining and with a plating and culture method (CFU/mL). Linear regression analysis was computed to demonstrate associations between the surface properties and biofilm growth. The strength of this relationship was quantified by calculating Spearman’s ρ. TC exhibited the highest, and TP the lowest IFT. TEC showed the highest R_a, while TEL had the lowest, with significant differences detected particularly between milled and 3D-printed specimens. TP specimens exhibited the highest biofilm mass, while ZR surfaces retained the least. Bacterial viability within the biofilms remained similar across all tested materials. There was a strong negative correlation between total IFT and biofilm mass, and a moderate positive correlation between R_a and CFU/mL. Surface properties are shaped by material composition, microstructure, and manufacturing methods and play a crucial role in biofilm formation on dental restorations. Full article

The interaction between moisture and textile materials plays a critical role in transient thermal comfort, particularly through the exothermic heat released during wetting. While the heat of wetting has been extensively characterized at the fiber level, its behavior in finished fabrics, where structure, porosity, and air gaps influence moisture uptake, remains poorly understood. This study quantifies the heat of wetting of clothing fabrics using a TAM Air isothermal microcalorimeter under controlled isothermal conditions (23 °C). Five fabric types representing different fiber chemistries (Merino wool, cotton, viscose, and polyester) were evaluated in both folded and dissected forms to assess the influence of sampling methods. Wool fabrics exhibited the highest heat release, followed by viscose and cotton, whereas polyester showed negligible exothermic response due to its non-hygroscopic nature. Overall, fabric-level heat of wetting values were lower and more variable than the corresponding fiber-level values reported in the literature, reflecting the combined effects of fabric structure, air permeability, surface hydrophilicity, and sampling uniformity. These findings demonstrate the feasibility and limitations of isothermal microcalorimetry for characterizing moisture–fabric interactions and highlight the need for improved sampling and measurement protocols to more accurately capture fabric-level sorption heat relevant to clothing comfort. Full article

Metal Injection Molding (MIM) enables complex orthodontic-bracket geometries but can introduce surface and geometric discontinuities that act as initiation sites for crevice and pitting corrosion. The effect of acidic, kombucha-like exposure on corrosion and repassivation was assessed for MIM-316L brackets relative to a commercial comparator, and the coupling between surface quality (roughness and wettability) and localized damage at scanning electron microscopy (SEM)-identified hot-spots was examined. Kombucha was characterized by pH and titratable acidity. Surfaces were characterized by SEM, areal roughness metrics (R_a, S_a, S_z, and A2), and wettability by sessile-drop goniometry. Electrochemical behavior in artificial saliva was measured using open-circuit potential and cyclic potentiodynamic polarization (ASTM F2129/G59), and a qualitative magnetic check was included as a pragmatic quality-assurance screen. Exposure in kombucha reduced breakdown and repassivation potentials and increased passive current density, with the strongest effects co-localizing geometric discontinuities. Commercial brackets exhibited markedly poorer surface quality (notably higher S_z), amplifying acidity-driven susceptibility. These findings indicate that, under acidic challenges, surface/geometry quality dominates corrosion behavior; non-magnetic-phase compliance and simple chairside screening (e.g., magnet test), alongside tighter manufacturing controls on roughness and edge finish, should be incorporated into clinical and industrial quality assurance (QA). Full article