Search Results (173)

Effective and sustainable livestock management within Mediterranean ecosystems depends heavily on accurate and timely monitoring of sward composition. Traditionally, this task has relied on human observers who must traverse large and often rugged areas to identify the distribution of grasses, legumes, shrubs, and other plant groups. However, this approach is not only labor-intensive and slow but also susceptible to substantial human error, especially when observations must be repeated frequently or carried out under difficult field conditions. In the present study, an alternative method that integrates wearable cameras with modern computer-vision techniques to automatically recognize pasture plant species through an edge device present in farm premises was investigated. Additionally, the feasibility of achieving reliable classification performance on resource-constrained edge devices was evaluated. To this end, five widely used pre-trained convolutional neural networks were compared against a lightweight custom model developed entirely from scratch. The results demonstrated that ResNet50 delivered the strongest classification accuracy, achieving a Matthews Correlation Coefficient (MCC) of 0.992. Nonetheless, the custom lightweight model proved to be a practical compromise for real-world field use, reaching an MCC of 0.893 while requiring only 6.24 MB of storage. The inference performance on Raspberry Pi 4, Raspberry Pi 5, and Jetson Orin Nano platforms was also evaluated, revealing that the Selective Search stage remains a major computational limitation for achieving real-time operation. The results obtained confirm the possibility of implementing a plant identification system in agricultural facilities without the need to transfer images to a cloud-based application. Full article

8Cr4Mo4V bearing steel is a critical material for main shaft bearings in aero-engine applications. However, the current understanding of the micro-mechanical properties of its matrix and primary carbide phases (vanadium-rich and molybdenum-rich carbides) remains insufficient. This knowledge gap readily induces various forms of deformation damage during grinding, severely compromising the surface integrity of the workpiece. To address this, nanoindentation and nano-scratch techniques were employed to systematically quantify the micro-mechanical properties of each phase and investigate the deformation damage behavior of the steel under load. Results showed that MC carbides exhibited the highest elastic modulus and microhardness, which made them more susceptible to becoming crack initiation sites during grinding. Nano-scratch testing further revealed that crack initiation at carbide edges and localized spalling were the primary damage mechanisms. This study provides a micro-mechanical foundation for controlling the grinding surface quality of 8Cr4Mo4V bearing steel, holding significant implications for optimizing grinding processes, suppressing crack initiation, and elucidating the grinding damage mechanism. Full article

Carbon–metal composite NiCrFeC coatings, prepared with and without controlled oxygen addition, were investigated to evaluate the influence of oxygen on the structure, mechanical response, and tribological performance. X-ray diffraction revealed that oxygen-containing films (NiCrFeC + O₂) exhibit a mixed metallic–oxide microstructure with CrNi, CrO, and NiO phases, whereas oxygen-free coatings show only CrNi crystalline peaks. The incorporation of oxygen led to a substantial increase in nano-hardness, from 0.84 GPa for NiCrFeC to 1.59 GPa for NiCrFeC + O₂. Scratch testing up to 100 N indicated improved adhesion and higher critical loads for the oxygen-rich coatings. Tribological measurements performed under dry sliding conditions using a sapphire ball showed a significant reduction in friction: NiCrFeC + O₂ stabilized at ~0.20, while NiCrFeC exhibited values between 0.25 and 0.35 at 0.5 N and 0.4–0.5 at 1 N, accompanied by non-uniform sliding due to coating failure. Wear-track analysis confirmed shallower penetration depths and narrower wear scars for NiCrFeC + O₂, despite similar initial roughness (~35 nm). These findings demonstrate that oxygen incorporation enhances hardness, adhesion, and wear resistance while substantially lowering friction, making NiCrFeC + O₂ coatings promising for low-friction dry-sliding applications. Full article

This study aimed to examine the influence of sputtering temperature on the bonding structure and properties of non-hydrogenated chromium/nickel co-doped diamond-like carbon (DLC) films synthesized via direct current magnetron sputtering. The Cr/Ni doping levels in the coatings were regulated by varying the shield opening above a chromium-nickel (20/80 at.%) target, resulting in a total metal co-doping concentration ranging from 6.1 to 8.9 at.%. The thickness of the Cr/Ni-DLC films ranged from 160 to 180 nm. Meanwhile, the deposition temperatures of 185 °C and 235 °C were achieved by adjusting the substrate-to-target distance. The XPS and Raman spectroscopy results indicated enhanced graphitization of the Cr/Ni-DLC films with a decrease in the synthesis temperature. XPS results indicated the formation of carbon-oxide and metal-oxide bonds, with no evidence of metal carbide formation in the doped DLC films. Furthermore, both the nanohardness and Young’s modulus demonstrated significant improvement, while the friction coefficient was reduced more than twice as the deposition temperature increased. These findings provide valuable insights into the influence of deposition temperature on Cr/Ni co-doped DLC films, highlighting their potential as advanced functional coatings. Full article

This work reports on the effects of surface pre-treatment and EPD process parameters on the nanomechanical and adhesive performance of chitosan-based composite coatings fabricated on a Ti13Zr13Nb alloy. Three different coating systems were prepared: chitosan–Cu (series A), chitosan–HAp (series B), and HAp–Cu (series C). Coatings were deposited from suspensions at different voltages (10–30 V) and for various times (1–2 min) onto polished, anodized, and laser surface-treated titanium alloy substrates. Microstructural, nanomechanical, and adhesion properties were characterized by means of SEM, nanoindentation, and nanoscratch testing, respectively. Chitosan–Cu coatings exhibited the highest hardness (up to 8.2 GPa) and stiffness due to the homogeneous dispersion of Cu nanoparticles and strong interfacial bonding to the underlying anodized TiO₂ layer. Chitosan–HAp coatings were softer (0.05–0.13 GPa) and highly plastic, particularly after laser surface treatment due to their specific porous, polymer-dominated structure. HAp–Cu coatings exhibited an intermediate mechanical behavior with a hardness between 0.1 GPa and 2.9 GPa and enhanced elastic recovery (Wp/We ≈ 3.5–4.7), particularly for anodized substrates. The nanoscratch test results showed that the HAp–Cu coatings exhibited the highest adhesion Lc (≈150–173 mN), confirming a synergistic effect of hybrid composition and heat treatment on interfacial toughness. The present data demonstrate that the optimization of anodizing and EPD processing parameters allows for the manipulation of the mechanical integrity and adhesion of bioactive chitosan-based coatings for titanium biomedical applications. Full article

Two Ni-AlSi12 coatings were prepared using mechanical alloying (MA) and mechanical alloying followed by laser cladding (LC), respectively. Phase composition and microstructure variations caused by powder weight ratio and laser-specific energy were thoroughly analyzed in this study. Mechanical properties and oxidation behavior are markedly improved by subsequent laser cladding. The MA-LC coating, characterized by high densification and crack-free properties, presents a homogeneous microstructure with refined features. Microhardness testing reveals a marked superiority of the MA-LC coating over the conventional MA coating. The nano-hardness of MA-LC coating is 9.79 GPa, exhibiting that it is 6.84 times the nano-hardness of the MA sample. Owing to metallurgical bonding, the MA-LC coating possesses excellent scratch bonding performance. The MA-LC coating shows favorable oxidation behavior, due to the following three reasons: Firstly, oxygen diffusion can be effectively blocked by the compact Al₂O₃ oxide layer developed on the MA-LC coating surface, which reduces the oxidation velocity. Secondly, the coating’s mean grain dimensions demonstrate an increasing tendency after oxidation, which reduces the grain boundary serving as the oxygen diffusion channel. This enhancement significantly improves the coating’s oxidation resistance. Thirdly, analysis of the coating’s respective kernel average misorientation (KAM) map revealed a significant release of internal stress following 100 h oxidation, which can improve the coating’s resistance to spallation. Full article

Cementitious materials are multiscale and multiphase composites whose frost resistance at the macroscale is closely governed by microstructural characteristics. However, the interfacial transition zone (ITZ) between clinker and hydrates, recognized as the weakest solid phase, plays a decisive role in the initiation and propagation of microcracks under freezing conditions. Understanding the frost damage mechanism of ITZ is therefore essential for improving the durability of concrete in cold regions. The motivation of this study lies in revealing how freezing affects the mechanical integrity and microstructure of ITZ in its early ages, which remains insufficiently understood in existing research. To address this, a nanoscratch technique was employed for its ability to quantify local fracture properties and interfacial adhesion at the submicronscale, providing a direct and high-resolution assessment of ITZ behavior under freeze–thaw action. The ITZ thickness and fracture properties were characterized in unfrozen cement paste and in cement paste frozen at 1 and 7 days of age to elucidate the microscale frost damage mechanism. Moreover, the enhancement effect of nano-silica modification on frozen ITZ was investigated through the combined use of nanoscratch and mercury intrusion porosimetry (MIP). The correlations among clinker particle size, ITZ thickness, and ITZ fracture properties were further established using nanoscratch coupled with scanning electron microscopy (SEM). This study provides a novel micromechanical insight into the frost deterioration of ITZ and demonstrates the innovative application of nanoscratch technology in characterizing freeze-induced damage in cementitious materials, offering theoretical guidance for designing durable concrete for cold environments. Full article

This paper investigates the influence of substrate grain size on the behavior of a multilayer CrN/CrAlN coating, with the bilayer thickness varying across the cross-section in the range of 200–1000 nm. The substrate tools were made of WC-Co sintered carbide with three different grain sizes. The coatings were subjected to mechanical and tribological tests to assess their performance, including nanohardness, scratch resistance, and tribological testing. The coating’s roughness was measured using a 2D profilometer. Additionally, the chemical composition and surface morphology were analyzed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX). The durability tests were performed on an industrial CNC machine tool on the particleboard. The results revealed that tools with ultra-fine nano-grain (S) and micro-grain (T) WC-Co substrates exhibited a significant increase in tool durability by 28% and 44%, respectively. Significant differences in the microgeometry of the substrate U, especially in relation to the tool based on substrate S, explain the lack of improvement in its durability despite the use of a multilayer coating. Full article

Graphene exhibits great potential as an anti-friction coating material in MEMS. However, its underlying microscopic friction-reduction mechanism remains unclear. In this paper, the microstructural evolution and nanomechanical behavior of graphene coatings on copper substrates were systematically investigated by AFM friction experiments and MD simulations. MD simulations reveal that the anti-friction properties of graphene coatings primarily stem from microstructural regulation and load-bearing reinforcement of the substrate. The graphene coatings increase indentation diameter by forming transition radii at the indentation edges, and suppress the plowing effect of the substrate by restricting atomic upward movement, both of which enhance the dislocation density and load-bearing capacity of the substrate. Additionally, graphene coatings also reduce the scratch edge angle, weakening the interlocking effect between the substrate and tip, further lowering the friction force. Experimental results indicate that the tribological behavior of graphene coatings exhibits staged characteristics: graphene coatings show excellent ultrafriction properties under intact structural conditions, while showing a higher friction force in wear and tear states. This research provides a theoretical basis and technical guidance for the development of anti-friction and wear-resistant coatings for micro-nano devices. Full article

This study examines the incorporation of chopped glass fiber and nano-silica into epoxy, focusing on their effects on the tribological and mechanical properties. Three reinforcement ratios (1 wt.%, 3 wt.%, and 5 wt.%) were analyzed by scratch tests and profilometric analysis. The coefficient of friction (COF), scratch depth, and scratch width values of the unreinforced epoxy resin were measured as 0.45, 37.73 µm and 479 µm, respectively. The addition of glass fibers contributed to improved scratch performance by restricting material removal and stabilizing groove morphology, although higher fiber ratios caused an increase in COF. The results indicated that nano-silica increased scratch resistance with a COF of 0.42 at 5 wt.%, giving a scratch depth of 19.92 µm and a scratch width of 166 µm. Glass fiber also improved scratch performance, although there were high COF values for higher ratios, which could be due to the aggregation effect of the fibers. Statistical validation of the results was carried out through the Taguchi method and ANOVA analyses. These analyses showed that reinforcement type and ratio played an important role in scratch behavior. SEM analyses of worn surfaces showed that nano-silica can dissipate stress and minimize plastic deformation to yield improved scratch morphology. Overall, the results emphasize the complementary role of glass fiber and nano-silica reinforcements in improving the scratch resistance of epoxy resin for industrial applications. Full article

This study systematically investigates the effects of aging treatment (AT) on the microstructure and properties of Cr/DLC coatings deposited via cathodic arc ion plating onto the surface of ECAP-7075 aluminum alloy. Utilizing a comprehensive approach combining performance tests (nanoindentation, nanoscratch testing, dynamic polarization analysis) with characterization tests (scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy), the synergistic effects of equal channel angular pressing (ECAP) and aging treatment(AT) were elucidated. The results demonstrate that the combined ECAP and AT significantly enhance the coating’s performance. Specifically, AT promotes the precipitation of η’ phase within the 7075 aluminum alloy substrate, increases the size of Cr₇C₃ crystallites in the Cr-based interlayer, improves the crystallinity of the Cr₇C₃ phase on the (060) or (242) crystal planes, and elevates the sp³-C/sp²-C ratio in the diamond-like carbon(DLC) top layer, leading to partial healing of defects and a denser overall coating structure. These microstructural transformations, induced by AT, result in substantial improvements in the mechanical properties (hardness reaching 5.2 GPa, bond strength achieving 15.1 N) and corrosion resistance (corrosion potential increasing to -0.698 V) of the Cr/DLC-coated ECAP-7075 aluminum alloy. This enhanced combination of properties makes these coatings particularly well-suited for high-performance aerospace components requiring both wear resistance and corrosion protection in demanding environments. Full article

This study investigates the anodization behavior and surface modification of Ti6Al4V (Ti64) alloy components fabricated via electron beam powder bed fusion (EB-PBF), aiming to enhance their performance in biomedical applications. Ti64 samples were manufactured using optimized EB-PBF parameters to produce a uniform microstructure and surface quality. Electrochemical anodization at 40 V and 60 V for 2 h generated self-organized TiO₂ nanotube layers, followed by a heat treatment at 550 °C to improve crystallinity while preserving the nanotube morphology. Characterization using scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed that a lower voltage produced uniform, compact nanotubes with moderate roughness and higher hardness, whereas a higher voltage generated thicker, less ordered nanotubes with larger diameters, increased roughness, and slightly reduced mechanical performance. X-ray diffraction (XRD) confirmed the presence of anatase TiO₂ phases, and energy-dispersive spectroscopy (EDS) analysis revealed a homogeneous distribution of Ti and O. Mechanical testing via nanoindentation and nanoscratch techniques demonstrated superior hardness and adhesion in nanotubes formed at lower voltage due to their compact structure. Electrochemical measurements indicated significantly enhanced corrosion resistance in anodized samples, attributed to the dense and chemically stable TiO₂ layer that acts as a barrier to aggressive ions and reduces active corrosion sites. In vitro bioactivity analysis further confirmed improved apatite formation on anodized surfaces. These results demonstrate the synergistic potential of EB-PBF and controlled anodization for modifying the surface properties of Ti64 implants, leading to improved mechanical behavior, corrosion resistance, and biological performance suitable for biomedical applications. Full article

This study investigates the mechanical and tribological behavior of a polydimethylsiloxane (PDMS)–silica nanocomposite coating over the temperature range extending from 24 °C to 120 °C. Nanoindentation tests revealed depth- and temperature-dependent variations in hardness and complex modulus. A time-dependent deformation model accurately captured the viscoelastic and viscoplastic behavior observed during sustained loading, providing predictive insight into the coating’s thermomechanical performance. Tribological evaluation through friction and nanoscratch testing demonstrated a temperature-induced increase in the coefficient of friction. The integration of mechanical and surface metrology and characterization techniques offers a comprehensive understanding of the coating’s behavior under thermal and mechanical stress. These findings support the design of robust nanocomposite coatings with superior functional performance for practical applications requiring enhanced mechanical stability, wear resistance, and thermal tolerance in challenging service environments. Full article

Single-crystal 4H silicon carbide (4H-SiC) is a key substrate material for third-generation semiconductor devices, where surface and subsurface integrity critically affect performance and reliability. This study systematically examined the evolution of surface morphology and subsurface damage (SSD) during nanoscratching of 4H-SiC under varying normal loads (0–100 mN) using a nanoindenter equipped with a diamond Berkovich tip. Scratch characteristics were assessed using scanning electron microscopy (SEM), while cross-sectional SSD was characterised via focused ion beam (FIB) slicing and transmission electron microscopy (TEM). The results revealed three distinct material removal regimes: ductile removal below 14.5 mN, a brittle-to-ductile transition between 14.5–59.3 mN, and brittle removal above 59.3 mN. Notably, substantial subsurface damage—including median cracks exceeding 4 μm and dislocation clusters—was observed even within the transition zone where the surface appeared smooth. A thin amorphous layer at the indenter-substrate interface suppressed immediate surface defects but promoted subsurface damage nucleation. Crack propagation followed slip lines or their intersections, demonstrating sensitivity to local stress states. These findings offer important insights into nanoscale damage mechanisms, which are essential for optimizing precision machining processes to minimise SSD in SiC substrates. Full article

Hastelloy is widely used in the manufacturing of high-temperature components in the aerospace industry because of its high strength and corrosion-resistant physical properties, as well as its ability to maintain excellent mechanical properties at high temperatures. However, with developments in science and technology, the amount of available components for use in high-temperature and corrosive environments is increasing, their structures are becoming more complex and varied, and requirements with regard to the surface quality of the components has also become more stringent. The integration of cold plasma (CP) and nano-lubricant minimum quantity lubrication (NMQL), within a multi-physics coupling-assisted micro-grinding process (CPNMQL), presents a promising strategy to overcome this bottleneck. In this paper, micro-grinding of Hastelloy C-276 was performed under dry, CP, NMQL, and CPNMQL conditions, respectively. Contact angle testing, X-ray photoelectron spectroscopy (XPS) analysis, and nano-scratch experiments were used to investigate the mechanism of CPNMQL and to compare the micro-milling performance under different cooling and lubrication conditions employing various characteristics such as grinding temperature, surface roughness, and 3D surface profile. The results showed that at different micro-grinding depths, the micro-grinding temperature and surface roughness were significantly reduced under CP, NMQL, and CPNMQL conditions compared to dry friction. Among them, CPNMQL showed the best performance, with 53.4% and 54.7% reductions in temperature and surface roughness, respectively, compared to the dry condition. Full article