Surface Roughness Research Articles

3D printed artificial coral reefs: design and manufacture

Applying 3D concrete printing (3DCP) technology to design and manufacturing can create a diverse configuration of the marine landscape. However, this combination of 3D technology and artificial coral products is still in the initial stage of research and application. Therefore, this study introduces a novel design shape model, bridging theory and experimental models. Two innovative design models have been presented, and one has been manufactured and assembled based on the optimal assembling process. The paper aims to propose a design shape model for artificial coral reefs that employs innovative 3D concrete printing technology to create rough surfaces with openings and cavities similar to those found in natural rocks. The proposed design shape for artificial coral reefs, successfully trialed in this research, can be used as a reference model. The procedure for essential works, including drawing, printing, assembling, and some techniques, is helpful for understanding and implementing the works presented in the study. The application of 3D concrete printing technology to an artificial reef fulfills an identified need and plays a crucial role in marine ecosystem restoration and protecting endangered habitats, thereby making a significant social impact while promoting sustainable development in construction. This paper fulfills an identified need to apply 3D concrete printing technology to manufacturing artificial coral reefs.

In Vitro Evaluation of the Effectiveness and pH Variation of Dental Bleaching Gels and Their Effect on Enamel Surface Roughness

Objectives: Potential adverse effects and pH-related effectiveness of bleaching agents have raised some concerns. The aim of this study was to compare three bleaching agents containing hydrogen peroxide (HP) and carbamide peroxide (CP) in terms of whitening effectiveness, pH variation, and changes in enamel surface roughness. Methods: After controlled staining with a black tea solution, 42 human enamel specimens underwent bleaching treatment using the following agents: HP 40%; HP 35%; CP 16%. Color changes were evaluated according to the CIEDE2000 system. Gel pH was measured before and after each application. Surface roughness (Sa) was assessed through optical 3D profilometry before and after bleaching treatment. Results: The whitening effectiveness was similar for HP 40% and HP 35% while CP 16% had significantly lower results. HP 40% showed a remarkable pH acidification (−0.41), while HP 35% and CP 16% showed a mild increase in pH values (+0.26 and +0.03, respectively), and the differences between HP 40% and HP 35% and between HP 35% and CP 16% were statistically significant. Sa slightly decreased in all groups after bleaching, with no significant differences among them and a significant difference in HP 40% before and after treatment. Conclusions: Similar bleaching results were achieved regardless of pH and HP concentration for HP-based agents, while a lower bleaching effect was observed for the less concentrated CP-based agent, as anticipated. Higher HP and greater tendency to pH instability induced more pronounced modifications of surface roughness. This in vitro study suggests that bleaching gels with neutral and stable pH ensure good bleaching effectiveness and are less likely to cause enamel surface changes.

In-Situ Nanoindentation Surface Topography of Lead-Free Piezoelectric Thin Films

Surface roughness significantly affects the performance of microelectromechanical systems (MEMS) and piezoelectric films. This study investigates the impact of surface roughness on the mechanical properties of thin piezoelectric films using nanoindentation and scanning probe microscopy (SPM). Four piezoelectric films with different thicknesses (220, 350, and 450 nm) and substrate configurations (LNO/SiO2/Si or LNO/Si) were analyzed. A discriminant analysis revealed that the fractal dimension is more effective than the arithmetic mean height (Sa) for distinguishing surfaces, with only 2% misclassification versus 25% for Sa. A multiscale analysis identified the Smr2 parameter with low-pass filtering at 140 nm as highly effective for surface discrimination, achieving only 0.1% misclassification. The analysis of the roughness parameter Sa at various scales showed that band-pass filtering at 500 nm yielded a 0.7% misclassification rate, indicating its relevance for fractal roughness characterization. Most relevant roughness parameters for mechanical property correlation were found: Smr2 with low-pass filtering at 500 nm correlated best with hardness (R2 = 0.82), and Vvc with low-pass filtering at 2 nm correlated best with reduced elastic modulus (R2 = 0.84). These results demonstrate that surface roughness features like valley volume and voids significantly impact the apparent mechanical properties of piezoelectric films.

The Effect of Bone Glue on the Performance of Traditional Painted Furniture Ground Layers

This research investigates how the inclusion of bone glue affects the performance of traditional painted furniture ground layers, particularly under dry–wet cycling conditions. The ground layers, applied to wood substrates in seven different ratios of bone glue to gypsum powder (10%, 20%, 30%, 40%, 50%, and 60%), were tested for mass changes, dimensional stability, adhesion, and surface roughness. The results showed that higher bone glue content (especially 50% and 60%) led to improved stability, reduced mass fluctuations, and better dimensional stability. The 50% bone glue sample exhibited the best overall stability with minimal weight change (<1.6%) and reduced shrinkage. Adhesion strength increased with bone glue content, reaching 3.48 MPa at 60% bone glue. Lower bone glue content resulted in poor adhesion and visible defects such as cracking and blistering. SEM analysis confirmed that higher bone glue content enhanced bonding between the ground layer and the wood substrate.

Surface modification of fabrics using dielectric barrier discharge plasma for improved antifouling performance

Surface modification of fabrics is an effective way to endow them with antifouling properties while still maintaining their key advantages such as comfort, softness and stretchability. Herein, an atmospheric pressure dielectric barrier discharge (DBD) plasma method is demonstrated for the processing of silk fabrics using 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (PFDS) as the precursor. The results showed the successful grafting of PFDS groups onto the surface of silk fabrics without causing damage. Meanwhile, the gas temperature is rather low during the whole processing procedure, suggesting the non-equilibrium characteristics of DBD plasma. The influence on fabrics of the processing parameters (PFDS concentration, plasma treatment time and plasma discharge power) was systematically investigated. An optimum processing condition was determined to be a PFDS concentration of 8wt%, a plasma processing time of 40 s and a plasma power of 11.87 W. However, with prolonged plasma processing time or enhanced plasma power, the plasma-grafted PFDS films could be degraded. Further study revealed that plasma processing of silk fabrics with PFDS would lead to a change in their chemical composition and surface roughness. As a result, the surface energy of the fabrics was reduced, accompanied by improved water and oil repellency as well as enhanced antifouling performance. Besides, the plasma-grafted PFDS films also had good durability and stability. By extending the method to polyester and wool against different oil-/water-based stains, the DBD plasma surface modification technique demonstrated good versatility in improving the antifouling properties of fabrics. This work provides guidance for the surface modification of fabrics using DBD plasma to confer them with desirable functionalities.

Comparative study of EDM on titanium diboride ceramic material using different electrode materials and dielectric fluid

Abstract Titanium diboride is a highly used material in aerospace industry due of its remarkable longevity. Its strength poses a problem to traditional machining methods. We want to improve the EDM process parameters in TiB2 material by comparing two different dielectric fluids and four different electrode materials. The input parameters were adjusted to find the optimal combination. By studying the fluctuations of output parameters such as MRR, TWR, SR and overcut when processing titanium diboride, researchers can gain valuable insights. This is achieved through experimental studies and the results are then verified using a theoretical regression model. Experimental results confirmed that discharge current, voltage and Ton had a remarkable influence on MRR, TWR and surface roughness in TiB2 material. It has been observed that tool wear rate when using kerosene-based dielectric fluids is higher than that of deionized water-based dielectric fluids. Tungsten copper electrodes cause slightly less tool wear than tungsten electrodes, and produce higher MRR overall, when compared to other three electrode materials. Using a dielectricand a copper electrode can help you obtain a smoother surface. When deionized water is used as adielectric fluid with tungsten electrodes, the crossover value drops dramatically. Brass electrodesproduce ahigher overcut value compared to the other three electrode materials. The microstructure of the EDM hole was distinguished by SEM analysis, and the material composition of TIB2 was determined by EDS analysis

Parametric Optimisation of Wire Electrical Discharge Machining of 15CDV6 HSLA Steel Using Taguchi Method

15CDV6 steel is a high strength bainitic High Strength Low Alloy (HSLA) steel with low concentrations of chromium, molybdenum, and vanadium as the main alloying constituents. This steel is very robust and well-tempered i.e., it has High strength and good toughness. It is used in the manufacture of transformers, electric motors, nuclear reactors, and its application to the aerospace industry for the manufacture of rocket motor cases is immense. Simplifying any process of machining is very difficult, since it basically includes forecasts of machining parameters and working requirements that are unpredictable and extremely non-linear in nature which influence the overall production Quality and costs. A key component of producing novel products, particularly for the automotive and aerospace sectors, is wire electro discharge machining (Wire-EDM). This technology got success and offers unique advantages for specific applications, such as working with hard, super-tough, brittle, or difficult-to-machine materials, producing intricate shapes, or achieving high precision. The high degree of the obtainable accuracy and the fine surface quality makes Wire-EDM valuable. The right selection of the process parameters or input variables is the considered as most important task in Wire Electro Discharge Machining of 15CDV6 HSLA steel material. The present work concentrates on optimisation of various process parameters are Pulse-on Time, Pulse-off Time, Water pressure and sensitivity on work material 15CDV6 HSLA steel, the output responses considered are Material Removal Rate (MRR), Surface Roughness (Ra), and Power Consumption (PC). Taguchi Method technique used on experimental results for optimisation and same results are analysed using Analysis of Variance (ANOVA) for identify percentage contribution of process parameters. This work helps in analysing the suitable process parameters and machining performance for machining of 15CDV6 steel and also reveals the research work area in which maximum research work can be done in future.

Enhancement of Machining Performance of Ti-6Al-4V Alloy Though Nanoparticle-Based Minimum Quantity Lubrication: Insights into Surface Roughness, Material Removal Rate, Temperature, and Tool Wear

In competitive industry, economical and environmentally friendly production techniques are essential. In this sense, cleaner and more sustainable machining techniques are the industry’s focus. In addition to green methods, effective parametric control is necessary for hard-to-cut materials, particularly titanium Ti-6Al-4V, which is extensively used in a diversity of industries, including aerospace, medical, and military applications. Therefore, the current study aims to improve the machining performance of Ti-6Al-4V alloy using sustainable lubrication conditions. The effect of Al2O3 nanoparticles based on the minimum quantity lubrication (N-MQL) condition on surface quality and productivity are compared with minimum quantity lubrication (MQL). The performance measures, including surface roughness (Ra), material removal rate (MRR), and temperature, are evaluated at three machining variables, i.e., cutting speed (Vc), feed rate (f), and depth of cut (ap). These performance measures are further assessed by tool wear and surface morphology analysis. ap, f, and Vc are the most influencing parameters for Ra, MRR, and temperature, regardless of lubrication mode. The optimized values of RA of 0.728443 µm, MRR of 2443.77 m3/min, and temperature of 337 °C are achieved at N-MQL. For the N-MQL state, the optimized values of Ra of 0.55 µm, MRR of 2579.5 m3/min, and temperature of 323.554 °C are attained through a multi-response optimization desirability approach. Surface morphology analysis reveals a smooth machined surface with no obvious surface flaws, such as feed marks and adhesion, under N-MQL conditions, which significantly enhances the surface finish of the parts. The machining performance under the N-MQL condition has been enhanced considerably in terms of an improvements in surface finish of 32.96% and MRR of 11.56%, along with a decrease in temperature (17.22%) and higher tool life (326 s) than MQL. Furthermore, Al2O3 is advised over MQL because it uses less energy and has reduced tool wear and improved surface quality, and it is a cost-effective and sustainable fluid.

Study on nanosecond pulsed laser micro-milling of stainless steel miniature gears with intersecting-axes

The utilization rate of miniature gears has increased sharply with the widespread application of micro-pumps, electronic equipment, and measuring instruments, and therefore the design and processing of miniature gear has become a subject of intense research. Current research has predominantly focused on machining miniature parallel-axes gears, but well-established machining methods for miniature intersecting-axes gears are still lacking. This paper presented a nanosecond pulsed laser micro-milling technology for miniature intersecting-axes gear (MIAG). Firstly, the 3D models of driving MIAG and driven MIAG were established, and the machining schemes were proposed on the basis of the characteristics of the models. Then, the influences of processing parameters such as defocusing distance, pulse overlap, and scanning strategy on the output responses, including removal rate, surface roughness, and shape accuracy were analyzed. Afterward, some miniature structures, such as miniature grooves, cylinders and cones, were machined by combining these process parameters. Finally, the MIAGs were machined, and the accuracy evaluation and kinematics experiment were carried out. The diameter of driving MIAG was 1.21 mm, and the diameter of driven MIAG was 3.389 mm. The experimental results indicate that the proposed machining technology can process MIAG with relatively high precision and can also offer a valuable reference for the manufacturing of other miniature components.

Mechanistic insights into waterjet-guided laser grooving of silicon: Impact of ablation dynamics, oxide formation, and thermal stress

Waterjet-guided laser machining of silicon offers precision with minimal heat-affected zones (HAZs), but understanding the mechanisms behind laser-material interactions remains essential. This study first utilizes orthogonal experiments to reveal fundamental relationships between processing parameters (scanning cycle, laser fluence, scanning velocity, and waterjet pressure) on groove depth and the depth-to-HAZ ratio. These findings guide the in-depth investigation of laser-material mechanisms. The results indicate that the ablation rate decreases with increasing scanning cycles, a phenomenon primarily attributed to the different absorption rates of 532 nm laser light between silicon and silicon dioxide. This conclusion is supported by x-ray photoelectron spectroscopy(XPS) results, which reveal that the accumulation of silicon dioxide occurs as the scanning cycles increase. Additionally, a near-linear relation between the ablation rate and laser fluence is observed, as the ablated area is continuously exposed to high laser intensity regions. However, increasing laser fluence also leads to diminished processing quality due to greater thermal deformation in non-ablating regions. Last, increased scanning velocity is found to cause rougher surfaces, as insufficient heat diffusion leads to higher thermal stress and results in micro-crack formations. The results provide a detailed understanding of the laser-induced transformations in the material and highlight optimal conditions for reducing thermal damage while maintaining machining efficiency. This study advances the field of laser processing by offering insights into the mechanisms governing oxide formation, thermal cracking, and material deformation during silicon grooving, providing the foundation for future exploration of laser-material interaction dynamics.

Testing Concrete Sewer Maintenance Holes Using an Angular Modulated Penetrometer

Around the world, a significant proportion of sewers and sewer maintenance holes are constructed from concrete. Unfortunately, one major problem with concrete sewer infrastructure is corrosion caused by biogenic hydrogen sulphide, which causes major issues for concrete structural integrity. Furthermore, concrete may be significantly corroded and softened but still pass a visual inspection. The novel system presented in this paper uses a penetrometer mounted on a robotic platform to measure the depth of penetration through a corroded concrete surface. An angular mechanism is used to rotate the penetrometer to new positions as striking aggregate may result in false readings. Based on laboratory analysis, this design is capable of providing consistent and precise multiple observations for both smooth and rough surfaces, as well as for flat and curved surfaces, with 0.1 mm accuracy. The use of a remote robotic platform eliminates the hazards of confined space entry whilst providing a repeatable analysis platform.

Nitrogen-Doped Diamond-like Coatings for Long-Term Enhanced Cell Adhesion on Electrospun Poly(ε-caprolactone) Scaffold Surfaces

Electrospun poly(ε-caprolactone) (PCL)-based scaffolds are widely used in tissue engineering. However, low cell adhesion remains the key drawback of PCL scaffolds. It is well known that nitrogen-doped diamond-like carbon (N-DLC) coatings deposited on the surface of various implants are able to enhance their biocompatibility and functional properties. Herein, we report the utilization of the pulsed vacuum arc deposition (PVAD) technique for the fabrication of thin N-DLC coatings on the surface of electrospun PCL scaffolds. The effect of N-DLC coating deposition under various nitrogen pressures on the morphological, mechanical, physico-chemical, and biological properties of PCL scaffolds was investigated. It was established that an increase in nitrogen pressure in the range from 5 × 10−3 to 5 × 10−1 Pa results in up to a 10-fold increase in the nitrogen content and a 2-fold increase in the roughness of the PCL fiber surface. These factors provided the conditions for the enhanced adhesion and proliferation of human mesenchymal stem cells (MMSCs) on the surface of the modified PCL scaffolds. Importantly, the preservation of N-DLC coating properties determines the shelf life of a coated medical device. The elemental composition, tensile strength, and surface human MMSC adhesion were studied immediately after fabrication and after 6 months of storage under normal conditions. The enhanced MMSC adhesion was preserved after 6 months of storage of the modified PCL-based scaffolds under normal conditions.

Interfacial and mechanical properties of silane coupling agent interface‐modified basalt fiber reinforced thermoplastic polypropylene resin composites

AbstractBasalt fiber (BF)‐reinforced thermoplastic composites are not only made with little environmental pollution and recyclable, with obvious environmental value, but also have excellent mechanical properties, excellent resistance to high temperature and corrosion. In the present study, modifications to the interface of BF were performed using monoaminosilane and diaminosilane agents, specifically 3‐aminopropyltrimethoxysilane (SATMS) and N‐(2‐aminoethyl)‐3‐aminopropyltrimethoxysilane (DATMS), along with a urea‐modified silane, 3‐urethylpropyltrimethoxysilane (SUTMS). These modifications were evaluated against one another. Utilizing a film lamination technique, composites of BF and thermoplastic polypropylene resin (BF‐PP) were fabricated. Analytical assessments included examining the modified fibers' surface morphology, chemical structure, and roughness. Mechanical assessments of the modified BF‐PP composites were conducted, revealing that composites treated with the urea‐inclusive silane agent (BF/SUTMS‐PP) exhibited superior performance, enhancing flexural strength by 26%, tensile strength by 22.4%, and notched Izod impact strength by 21%. However, because of the lower thermal stability of SUTMS, when the processing temperature exceeds 240°C, there is a decomposition of the heated Y‐base end, thus affecting the mechanical properties of BF/SUTMS‐PP.Highlights The basalt fibers were modified by SATMS, DATMS, and SUTMS. The urea‐containing silane coupling agent has the strongest enhancement effect. Composite reinforced with SUTMS‐BF displayed the best mechanical properties.

Isolation and Characterization Lignin of Sugar Palm Fruit Shell by Klason Method

Sugar palm fruit shell is one of the biomass wastes that contains lignocellulose. Lignin is a valuable material that can be earned from the isolation of lignocellulosic material. In this work, lignin was isolated from palm fruit shell waste by Klason method with 72% sulfuric acid after removing free extractive by soxhlation process. The isolated lignin was analyzed to determine the functional groups, surface morphology, and thermal stability using Fourier Transform Infrared spectroscopy, Scanning Electron Microscopy and Energy Dispersive X-ray. This work aimed to isolate and characterize lignin from palm sugar fruit shells. The yield of lignin in this experiment was 27%. The water content, ash, and lignin pH obtained were 4.50%, 3.41% and 9.98. The Fourier Transform Infrared spectroscopy spectra showed the many functional groups contained in lignin, such as carbonyl, hydroxyl, amine, ether, methoxy, and aromatic components. The Scanning Electron Microscopy showed a rough and porous surface. The Energy Dispersive X-ray showed the elemental composition in lignin, such as carbon, oxygen, and some inorganic elements. The Thermogravimetric Analysis showed that weight loss of lignin reached 47.948 % or 5.082 mg at 600°C. The characteristics of lignin obtained from sugar palm fruit shell by Klason showed that it had potency as a good material for further application.

Application of Powder-Bed Fusion of Metals Using a Laser for Manufacturing of M300 Maraging Steel Tools Intended for Sheet Metal Bending

This paper presents the results of a pilot application of Powder-Bed Fusion of Metals Using a Laser (PBF-LB/M) for the fabrication of M300 (1.2709) maraging steel sheet metal bending tools. S235 steel was used as a substrate for the fabrication of bending punches. The main goal of the research was to determine the usability of such tools without heat treatment, which would contribute to the increase in the cost of tool production. Industrial tests of tools were conducted during the forming of Inconel 625 and AW-6061 T0 aluminium alloy sheets. The punches were subjected to tests of surface roughness, hardness, microstructure, porosity, and geometric quality in order to verify the quality and accuracy of tools made by the PBF-LB/M technique before and after experimental investigations in industrial conditions in a selected manufacturing company. It was found that tools with an M300 steel working layer after the PBF-LB/M process without heat treatment show suitability for bending sheet metal in a certain range of force parameters, ensuring obtaining elements after bending from Inconel 625 and AW-6061 T0 aluminium alloy sheets of the required geometric quality.

Review on Superhydrophobic Polymer Composite Coating Materials and its Coating Technology for Advanced Applications

ABSTRACT Researchers all over the world are working to produce improved polymeric materials suitable for cutting-edge advanced applications that will eventually replace traditional materials. Polymeric materials that display super hydrophobic characteristics are quite valuable and interesting when it comes to the development of things with lotus leaf surface effects. In recent decades, super hydrophobic surfaces (SHS) have been considered as key parameter, and superhydrophobic coatings are vital to achieve materials with hydrophobic surface. The most crucial criteria influencing super hydrophobic surfaces are low surface free energy and higher surface roughness. Explorations on superhydrophobic surfaces (SHS) are very interesting because of their importance in varied nature of industrial, engineering and bio-medical applications. Superhydrophobic membranes have made a lot of curiosity recently, especially for efficient oil-water separation application. A major exploitation of these SHS is to increase the corrosion resistance of surfaces exposed to corrosive environments as well as their long-term chemical stability and maintaining the superhydrophobic characteristics. The other major important sectors utilize these materials to achieve ultra-superhydrophobic behavior are space and aerospace, defense, automotive, marine, water-oil separation, biomedical-engineering, and sensors. Superhydrophobic surfaces repel water primarily due to their surface texture and physicochemical properties. The present article deals with the basic and fundamental principles, importance and applications of superhydrophobic behavior of materials, including different analytical and fabrication techniques used to study and to ascertain the super hydrophobic properties of the materials.

Scalable production of ultraflat and ultraflexible diamond membrane.

Diamond is an exceptional material with great potential across various fields owing to its interesting properties1,2. However, despite extensive efforts over the past decades3-5, producing large quantities of desired ultrathin diamond membranes for widespread use remains challenging. Here we demonstrate that edge-exposed exfoliation using sticky tape is a simple, scalable and reliable method for producing ultrathin and transferable polycrystalline diamond membranes. Our approach enables the mass production of large-area (2-inch wafer), ultrathin (sub-micrometre thickness), ultraflat (sub-nano surface roughness) and ultraflexible (360° bendable) diamond membranes. These high-quality membranes, which have a flat workable surface, support standard micromanufacturing techniques, and their ultraflexible nature allows for direct elastic strain engineering and deformation sensing applications, which is not possible with their bulky counterpart. Systematic experimental and theoretical studies reveal that the quality of the exfoliated membranes depends on the peeling angle and membrane thickness, for which largely intact diamond membranes can be robustly produced within an optimal operation window. This single-step method, which opens up new avenues for the mass production of high-figure-of-merit diamond membranes, is expected to accelerate the commercialization and arrival of the diamond era in electronics, photonics and other related fields.

Addendum to ‘Assessment of offshore wind power including effects of sea surface roughness using observed wind statistics’: Assessment using sea surface roughness depending on spectral bandwidth of ocean waves

This addendum addresses the assessment of offshore wind power based on observed mean wind speed statistics from 11 sites in the North Sea and the North Atlantic. The wind gust and the ambient turbulence level are also estimated by adopting a wind gust spectrum. The sea surface roughness is specified using a recently published sea surface drag coefficient given in terms of the spectral bandwidth of ocean waves. The results are supplementary to those in a recent paper published by the present authors using the same mean wind speed statistics and wind gust spectrum, but with a different sea surface roughness formula depending on significant wave height and spectral wave steepness. It is demonstrated how the spectral bandwidth affects the assessment of the offshore wind power and the ambient turbulence level. Thus, since the spectral bandwidth is a frequently used parameter to characterize wave conditions the results should be useful.

Improving Room Temperature Formaldehyde Sensitivity with Samarium-Doped Titanium Dioxide

Abstract Samarium (Sm)-doped titanium dioxide (TiO₂) thin films were synthesized using the spray pyrolysis technique at 400°C, with Sm doping concentrations of 0, 2, 4, and 6 Wt.% to enhance structural, optical, morphological, and gas-sensing properties. The films, deposited on ultrasonically cleaned glass substrates, were characterized using X-ray diffraction , scanning electron microscopy, atomic force microscopy (AFM), and UV-Vis spectroscopy. Structural analysis revealed improved crystallinity and uniform surface morphology with Sm doping, while AFM indicated increased surface roughness, promoting gas adsorption. UV-Vis analysis showed a reduced energy bandgap, enhancing visible light absorption and gas-sensing performance. Gas sensing evaluations demonstrated high sensitivity to formaldehyde, with notable selectivity over ethanol, toluene, and xylene at room conditions. The 6 Wt.% Sm-doped TiO₂ film exhibited the highest response (17.4), with a detection limit of 5 ppm, and fast response (23 s) and recovery (27 s) times. These properties underline the potential of Sm-doped TiO₂ films for efficient room-temperature gas sensors. Their enhanced sensitivity, selectivity, and stability suggest promising applications in environmental monitoring and air quality management, particularly for formaldehyde detection and volatile organic compound discrimination.

Effect of Peening Media Type on the High‐Cycle Tensile–Tensile Fatigue Properties of Ti‐6Al‐4V Alloy by Ultrasonic Shot Peening

ABSTRACTThis study investigates the effect of ultrasonic shot peening (USP) on Ti‐6Al‐4V samples using cast steel and zirconia ceramic shots at the same intensity. The surface integrity of the samples before and after treatment was characterized, and tensile–tensile fatigue tests were conducted under various stress amplitudes to compare the improvements in fatigue performance. The mechanisms underlying the enhancement of fatigue properties were analyzed by examining microstructural changes and fracture morphologies. The results show that, compared to steel shot, zirconia ceramic shot leads to lower surface roughness, finer surface grains, and more significant work hardening and plastic deformation. These factors contribute to a more pronounced improvement in the fatigue performance under tension–tension loading of Ti‐6Al‐4V under USP treatment. The superior performance of ceramic shot can be attributed to low density combined with high hardness of the ceramic shot.