Material Surface Research Articles

Super‐adaptive electroactive programmable adhesive materials to challenging surfaces: From intelligent soft robotics to XR haptic interfaces

AbstractRecently, the intelligent strategies for adapting to multiple challengeable surfaces of electroactive programmable materials integrated with bio‐inspired architectures offer expanded directions beyond traditional limitations in soft grippers, medical mobile robots, and XR (Extended Reality) interfaces. These electroactive programmable adhesive materials are adaptively designed for a variety of complex surfaces, including soft, wet, non‐flat, or contamination‐susceptible feature such as bio‐surfaces and vulnerable objects. They can be produced via solution‐based methods of replica coating or 3/4‐dimensional printing. The integration of electroactive programmable materials and intelligent adhesive architecture enables super‐adaptive switchable adhesion to a variety of complex surfaces through control of physical deformation and mechanical properties at the adhesive interface, presenting a breakthrough in soft electro‐robotics and extended reality (XR) Haptic interfaces technology. These surface‐adaptive platform can provide multiple functionalities that can efficiently control physical deformations of soft bioinspired architectures or transfer physical energy (heat, vibration, pressure) into the engaged surfaces in a lightweight and human‐friendly form. This review focuses on intelligent strategies, principles, design, and fabrication methods of super‐adaptive electroactive programmable materials intelligently combined with bioinspired switchable adhesives for next‐generation human–robot interaction devices, along with current challenges and prospects.image

Investigation of dissolution behavior and surface integrity in electrochemical machining of nickel-based superalloys

ABSTRACT Dissolution behavior and surface integrity during the electrochemical machining (ECM) of nickel-based superalloys are vital for the performance of components. This study examines IN718, 718Plus, and Rene 65 alloys focusing on material removal mechanisms, surface morphology, intergranular corrosion, three-dimensional profiles, surface roughness, microhardness, and residual stresses. The results indicated that as the current density increased, the MRR of all three alloys increased linearly, while the current efficiency initially fluctuated before stabilizing. At low current densities, selective dissolution and intergranular corrosion resulted in rough surfaces for the alloys examined. In contrast, higher current densities produced smooth and uniform surfaces for these alloys. After electrochemical treatment, the surface microhardness of all alloys was reduced, and there was a slight decrease in residual stresses as well. These findings support the development of more precise and effective strategies for achieving higher surface integrity in the ECM of nickel-based superalloys.

Kinetic Modeling in Temperature-Modulated Semiconductor Gas Sensor Utilizing Eley-Rideal Mechanism and Its Application in Discriminative Detection of VOCs.

This study presents a comprehensive kinetic investigation for describing the dynamic sensing process of semiconductor metal oxide (SMO)-based gas sensors, with a focus on the Eley-Rideal mechanism as a valid pathway. The modeling elucidates the direct interactions between volatile organic compounds (VOCs) and adsorbed oxygen on the material surface, providing insights into the temperature-dependent response characteristics of the sensor and addressing selectivity toward different VOCs fundamentally. By incorporating the effects of thermal modulation, the kinetic model was validated through theoretical fitting of experimental data obtained from a fabricated SnO2 nanoparticle gas sensor exposed to ethanol, n-propanol, toluene, and butanone at systematically varying operating temperatures. The results demonstrated that the model accurately captures response transient values, enabling a general framework for qualitatively discriminating specific gases based on their unique reaction kinetics. Furthermore, a machine learning procedure containing the above model and power laws of quantitative concentrations after identifying compounds was developed for the prediction of target VOCs. The qualitative accuracy was determined to be 99.4%, while quantifying with the mean absolute errors of 5.0, 7.5, 4.0, and 8.9 within the range of 25-200 ppm, respectively. The precise and straightforward strategy facilitates the response modeling of SMO-based gas sensors, offering a valuable platform for the designing model-driven algorithms applicable in gas analysis and monitoring.

Study on the Properties and Mechanism of m‐FACs/f‐Fe3O4/Epoxy Wear‐Resistant Magnetic Coating

ABSTRACTIn view of the wear problem of key parts of magnetic fluid seal device, epoxy resin (EP) composite coatings reinforced with Fe3O4 and fly ash cenospheres (FACs) were fabricated successfully. The structural and morphological features of the fillers and the composite coatings were characterized by Fourier transform infrared and scanning electron microscopy. CFT‐I material surface performance comprehensive tester was used to investigate the tribological behaviors of the as‐prepared composite coatings. Vibrating sample magnetometer was used to investigate the coatings' magnetic property. The formation mechanism of the composite coating was analyzed by the infrared spectrum results combined with molecular dynamics simulations. The results demonstrated that adding a certain amount of double fillers will have a synergistic effect, and its mechanical properties are better than those of single fillers. The tribological property of the m‐FACs/f‐Fe3O4/EP composite coatings was optimal under magnetic fluid friction, which is about an order of magnitude lower than the wear rate under dry friction. The saturation magnetization of the m‐FACs/f‐Fe3O4/EP composite coating is 2.77 emu/g, and the magnetic susceptibility reaches 4.64 × 10−4 m3/kg. Therefore, the m‐FACs/f‐Fe3O4/EP composite coating will be expected to solve the wear problem of equipment components in complex environments of magnetic field and friction.

Study on the mechanical properties of layered gradient structure PBT-based flame retardant composite materials

Abstract To enhance the flame retardancy of Polybutylene Terephthalate (PBT) based composite materials and overcome the decrease in mechanical properties due to the high content of nano-antimony trioxide (nano-Sb2O3), this study initially applies a composite modification method to treat the surface of nano-Sb2O3. Subsequently, composite materials with a gradient distribution of nano-Sb2O3 are prepared through lamination hot-pressing technology, and their mechanical and flame retardant properties are investigated. The results show that the modifiers CTAB and KH560 are successfully grafted onto the surface of nano-Sb2O3, altering its surface properties. Through lamination hot-pressing technology, a gradient distribution from the surface to the core is achieved. Compared to the homogeneous distribution P666, G828 exhibits a 6% increase in Limiting Oxygen Index (LOI), improving the flame retardancy of the composite material. As nano-Sb2O3 enriches on the composite material's surface, the amount of char residue increases. The tensile strength, bending strength, and impact strength of G828 composite material increase by 19.7%, 37.1%, and 103%, respectively, compared to the homogeneous composite material P666, proving the significant effect of G828's gradient distribution in enhancing the mechanical properties of the composite material.

Zn-Modified TiO2 Thin-Films for Real-Time Formaldehyde Sensing at Room Temperature

Abstract This study explores the fabrication and application of zinc-modified titanium dioxide (Zn-TiO2) thin-films for real-time recognition of volatile organic compounds (VOCs), with a particular emphasis on formaldehyde (HCHO) sensing at room temperature. The Zn-TiO2 thin-films were produced using an economical spray-pyrolysis method. Structural, morphological, and optical characterizations confirmed the successful integration of zinc with varied Wt.% (0, 2, 4, and 6) into the TiO2 lattice. The real-time monitoring capabilities of the sensors were assessed against a range of VOCs, highlighting its specificity for formaldehyde detection amidst diverse environmental constituents. The fabricated thin film sensors with zinc dopant were optimized to enhance the sensor's performance. 4 Wt.% Zn-TiO2 demonstrated excellent sensitivity to formaldehyde vapor at ambient conditions, showcasing a rapid and selective response. The underlying sensing mechanism was explored, emphasizing the role of zinc doping in tailoring the material's surface properties and facilitating enhanced adsorption of formaldehyde molecules. The study underscores the potential of Zn-modified TiO2 thin films as a reliable and efficient platform for real-time VOC monitoring, with a specific focus on HCHO sensing at room-temperature. The sensor shows remarkable stability and repeatability, making it a promising candidate for continuous monitoring applications.

Orthogonal Agent Comprising a Nitrile N-Oxide and a Phenylcarbamate for Facile Molecular Integration on Styrne-Butadiene Resin.

The covalent attachment of poly(ethylene glycol) (PEGylation) to materials minimizes non-specific fouling of the material surface with biocomponents. While the PEGylation reaction on polar surfaces is widely used and regarded as a common technique, the PEGylation on less polar polymers and elastomers is extremely difficult due to the absence of reactive points with PEG terminus. Herein, the design and synthesis of an orthogonal agent with a nitrile N-oxide and a phenyl carbamate that can mediate between an alkene and an amine are reported. The ligation capacity of the orthogonal agent is demonstrated through the model reaction to connect between 1-hexene and 4-methoxybenzylamine and the grafting reaction of PEG onto poly(styrene-co-butadiene) (SB) resin. The surface characteristics of PEGylated SB film are evaluated by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. Because SB resin is frequently used as a 3D-printing polymer, the present study indicates that the orthogonal agent can be applicable to the surface modification of 3D-printed objects precisely manufactured by using a computer-aided design (CAD) file in the future.

Droplet impact dynamics on the surface of super-hydrophobic BNNTs stainless steel mesh.

The 'gas‒liquid‒solid' mechanism annealing method was used to create a superhydrophobic boron nitride nanotube (BNNT) stainless steel mesh in a tube furnace at 1250°C in an NH3 environment. Fe powder was used as a catalyst, and B:B2O3 = 4:1 was used as the raw material. The water droplets on the surface of the superhydrophobic material had a contact angle of approximately 150° and a slide angle of approximately 3°. By using molecular dynamics (MD) simulation technology, a three-dimensional braided physical model of nanodroplets and superhydrophobic BNNT mesh surfaces with the same contact angle and rolling angle was prepared via the function weaving method. The Weber number (We) was used as the entrance point to establish the relationship between macroscale experimental studies and nanoscale MD simulation analysis on the basis of these efforts. A study was conducted on the dynamic behaviour of droplets impacting a superhydrophobic BNNT filter surface. We suggest that the wettability, substrate structure, and impact velocity are connected to the impact dynamic behaviour of droplets on the basis of the data obtained at various scales. The findings demonstrate that when the droplet impact velocity increases, several droplet phenomena-such as impact-rebound, impact-spread-rebound, and impact-spread-breaking-polymerisation-spatter-appear on the substrate surface sequentially. The mechanism of impact behaviour at various scales is explained in light of these events. Furthermore, a better theoretical model is proposed to assess the droplet wetting transition at the nanoscale. This model accurately predicts the boundary Weber number that starts the wetting transition. Moreover, the connections among the impact velocity, spreading diameter, and contact time (or We) are examined. The tendencies found via MD simulations match the outcomes of the experiments. Our discoveries and outcomes broaden our understanding of how droplet impact affects the dynamic behaviour of superhydrophobic surfaces. A scientific foundation for examining the dynamic behaviour of droplets is provided by combining simulations and experiments.

Surface Reconstruction Reduces Internal Stress of Ni-Rich Cathode Particles.

High-voltage Ni-rich layered cathode materials are undoubtedly a powerful driving force for high-energy density lithium batteries. However, residual lithium impurities on the surface of Ni-rich materials can cause more severe side reactions under high-voltage, leading to rapid decay. There is still no reliable mechanistic explanation for this phenomenon. It has been detected that residual alkali on the cathode surface under high voltage can cause obvious side reactions. This side reaction will affect the capacity retention of the material and increase the internal stress of the particles. In addition, the surface reconstruction of Ni-rich cathodes is achieved through simple chemical reactions, turning waste into treasure. The newly generated Ti-based layer not only repairs the structure of the nickel-rich material but also optimizes the material from a dynamic perspective. Removing residual lithium components on the cathode surface effectively reduces the hydrolysis and self-catalytic side reactions of PF6 - at the electrolyte cathode interface and suppresses gas generation during cycling, promoting the application of the next generation of high-energy density Ni-rich layered cathode-based lithium batteries with high-voltage.

Ultrasensitive Acetone Gas Sensor Based on a K/Sn-Co3O4 Porous Microsphere for Noninvasive Diabetes Diagnosis.

The detection of acetone in human exhaled breath is crucial for the noninvasive diagnosis of diabetes. However, the direct and reliable detection of acetone in exhaled breath with high humidity at the parts per billion level remains a great challenge. Here, an ultrasensitive acetone gas sensor based on a K/Sn-Co3O4 porous microsphere was reported. The sensor demonstrates a detection limit of up to 100 ppb, along with excellent repeatability and selectivity. Remarkably, without the removal of water vapor from exhaled breath, the sensor can accurately distinguish diabetic patients and healthy individuals according to the difference in acetone concentrations, demonstrating its great potential for diabetes diagnosis. The enhanced sensitivity of the sensor is attributed to the increased oxygen adsorption on the material surface due to K/Sn codoping and the stronger coadsorption of Sn-K atoms to acetone molecules. These findings shed light on the mechanisms underlying the sensor's improved performance.

Orthogonal Nano‐Engineering (ONE): Modulating Nanotopography and Surface Chemistry of Aluminum Oxide for Superior Antibiofouling and Enhanced Chemical Stability

AbstractDecoupling certain material surface properties can be key to attaining critical property‐activity relationships that underpin their antibiofouling performance. Here, orthogonal nano‐engineering (ONE) is employed to decouple the influences of nanotopography and surface chemistry on surface antibiofouling. Nanotopography and surface chemistry are systematically varied with a two‐step process. Controlled nanotopography is obtained by electrochemical anodization of aluminum, which generated anodic aluminum oxide (AAO) surfaces with cylindrical nanopores (diameters: 15, 25, and 100 nm). To modify surface chemistry while preserving nanotopography, an ultrathin (≈5 nm) yet stable zwitterionic coating of poly(divinylbenzene‐4‐vinylpyridyl sulfobetaine) is deposited on these surfaces using initiated chemical vapor deposition (iCVD). Antibiofouling performance is assessed by quantifying 48‐h biomass formed by gram positive and negative bacteria. The ONE surfaces demonstrated enhanced antibiofouling performance, with small‐pore nanotopography and zwitterionic chemistry each lowered biomass accumulation by tested species, with potential additive effects. The most effective chemistry‐topography combination (ZW‐AAO15) enabled an overall reduction of 91% for Escherichia coli, 76% for Staphylococcus epidermidis, 69% for Listeria monocytogenes, and 67% for Staphylococcus aureus, relative to the uncoated nanosmooth control. Additionally, the composite ZW coating exhibited encouraging anticorrosion properties under both static and turbulent cleaning conditions, vital to antibiofouling applications in healthcare and food industries.

FRICTION STIR PROCESSED MAGNESIUM MATRIX SURFACE COMPOSITES: A COMPREHENSIVE REVIEW

Abstract Nowadays modern materials are tailored using different manufacturing techniques. Usually, material surface is modified by even distribution of reinforcement particles/ fibres up to a certain depth. The developed surface metal matrix composites (MMCs) exhibit superior metallurgical, mechanical and electrochemical properties in contrast to base materials. These surface MMCs have potential applications in biomedical, automotive, aerospace and power industries. Many techniques have been used to develop these surface MMCs, however, the friction stir processing (FSP) has gained wide popularity. This review paper summarizes the effects of different FSP parameters on the metallurgical, mechanical and electrochemical properties of developed surface composites. Furthermore, the effects of secondary phase particles on the Magnesium-matrix surface composites are also comprehensively discussed.

Laser pretreatment enhances the laser-induced damage threshold of MgAl2O4 transparent ceramics

The demand for transparent ceramics as essential optical components in high-energy laser systems is escalating. Given the continuous surge in laser output power, there is an urgent need to enhance their laser-induced damage threshold (LIDT). This research systematically investigates the influence of variables such as laser energy density, number of scan repetitions, and stepwise scanning on the LIDT of MgAl2O4 transparent ceramics by modulating the process parameters of laser pretreatment. Through this method, oxygen vacancy defects on the material surface were effectively minimized, achieving surface purification of transparent ceramics and reducing residual stress. Under a consistent laser energy density of 8.96 J/cm2, the transparent ceramics were subjected to 1 to 9 scanning passes. The LIDT showed a progressive increase with the number of scans, reaching a maximum value of 15.0 J/cm2 after seven scans, which corresponds to a 34% improvement compared to untreated samples. Additionally, laser pretreatment facilitated the expansion of the material's bandgap and increased transmittance in the 200-300 nm band, further substantiating the intimate relationship between the reduction of oxygen vacancy defects and the improvement of optical properties. The findings indicate that laser pretreatment, as an effective post-processing technique, can substantially augment its resistance to laser damage by optimizing the microstructure and surface characteristics of the material. Moreover, judicious control of laser energy density and number of scan repetitions is crucial for optimally improving LIDT. In conclusion, this study offers what we believe to be a new theoretical foundation and technical support for the performance optimization of transparent ceramics in high-power laser systems, underscoring the significant potential of laser pretreatment as an effective post-processing technology in enhancing material optical properties and durability.

Magnetic PDMS@SiO2/Fe3O4 Composite Friction Layer Material for Enhanced Friction Nanogenerator Output Performance

Triboelectric nanogenerators (TENG) have exhibited remarkable potential in harnessing stochastic low-frequency mechanical energy from oceanic surfaces, attributed to their versatile architectures and capability for extensive deployment. Nonetheless, the relatively modest power output per unit area remains a critical limitation impeding the advancement of TENG technology. Consequently, the innovation of novel material systems and devices to augment the output performance and efficiency of TENG is paramount in achieving effective ocean energy exploitation. In our study, a vertical contact PC-TENG was utilized as an energy harvester, with the incorporation of magnetic nano-oxide particles to bolster the output efficiency of TENG. This investigation represents the inaugural application of SiO2 and Fe3O4 nanoparticles within PDMS negative friction layers. This strategy augments the specific surface area, thereby improving the contact between the friction materials and enhancing charge transfer efficiency. Moreover, the magnetic properties of Fe3O4 facilitate charge separation on the material's surface, culminating in an elevated voltage output. Comprehensive characterizations were conducted using SEM, FTIR, electrometer, and contact angle meter, while simulations were corroborated with COMSOL Multiphysics field simulation software. The output performance witnessed optimization through the incorporation of Fe3O4, culminating in a peak open-circuit voltage (VOC) of 85.1212 V, a maximum short-circuits current (ISC) of 8.4037 μA, and a maximum transferred charge (QSC) of 0.5638 nC, reflecting enhancements of 28%, 32%, and 27%, respectively, compared to conventional PDMS materials. The peak output power, achieved with an impedance match of 55 MΩ, was recorded at 19.03 mW, marking a 70.8% improvement in output performance. The findings revealed that the contact angle of PDMS@SiO2/Fe3O4 composites reached 100.092°, enhancing hydrophobicity by 8% relative to traditional PDMS materials, thereby rendering it more suitable for humid environments. COMSOL Multiphysics field simulation results further substantiated the viability of the PDMS@SiO2/Fe3O4 composite friction layer material for applications in oceanic wave environments. Ultimately, a rectifier bridge was introduced to convert the alternating current generated by the PC-TENG into direct current. This research offers a novel paradigm for the utilization of TENG in the realm of marine energy.

Process optimization and finite element modeling in magnetorheological abrasive finishing of SS-316L with surface characterization

This study explores the potential of Magnetorheological Abrasive Finishing (MRAF) for ultra-precision finishing of SS-316L using a high-performance Nd-Fe-B (N-35 grade) magnetic tool. Key parameters, including the relationship between normal force (Fn) and working gap, magnetic flux distribution, and finishing spot area, were analyzed using ANSYS 2020 R1® Magnetostatic module simulations. Material removal rate (MRR) and surface roughness (Ra) were optimized through response surface methodology (RSM) using a central composite design (CCD) with two primary input factors: SiC abrasive volume fraction (5%, 10%, 15%) and abrasive mesh size (800, 1000, 1200). Statistical analysis via ANOVA revealed a significant influence of process variables, achieving a remarkable surface finish with a minimum Ra of 52 nm in just 60 min, utilizing an MR fluid with 10% SiC abrasives. Microscopic and spectroscopic evaluations confirmed enhanced surface morphology and microstructural refinement. Moreover, bioactivity studies in simulated body fluid highlighted improved hydroxyapatite layer formation on the finished SS-316L samples, underscoring the process’s potential for biomedical applications.

Effect of pinless friction stir processing on microstructure and properties of surface modification layer of 2024 aluminum alloy

Friction stir processing (FSP) is an advanced material surface modification technology that is both green and energy-efficient. This technology plays a crucial role in regulating the surface microstructure of alloys and improving alloys’ surface properties. It reaches this through the synergistic effect of non-equilibrium thermodynamic and surface mechanical deformation. In this work, the surface modification of an aluminum alloy was performed using pin-less FSP. Then, the modified surface was analyzed using stress–strain curves, optical microscopy (OM), x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electrochemical tests to investigate the impact of spindle velocity on the properties of the modified layer. Results of the study show that after undergoing pinless FSP modification treatment, the surface of the alloy appears bright and flat. The modified layer displays refined grains and numerous dispersed second-phase particles. Furthermore, the grains in the modified layer exhibit a gradient distribution from the surface to the matrix. Regarding the properties, compared to the base material (BM), the yield strength (σ 0.2) and tensile strength (σ b ) of the alloy-modified layer were increased by 34.8% and 29.4%, respectively. The maximum elongation (δ) of the modified coating reached 22.3%. The modified layer exhibits a tough-brittle mixed fracture pattern. Additionally, the modified layer’s corrosion resistance significantly improves. The performance of the modified coating shows the most significant improvement when the spindle speed reaches 1000 rpm.

Research on a Method for Measuring the Pile Height of Materials in Agricultural Product Transport Vehicles Based on Binocular Vision

The advancement of unloading technology in combine harvesting is crucial for the intelligent development of agricultural machinery. Accurately measuring material pile height in transport vehicles is essential, as uneven accumulation can lead to spillage and voids, reducing loading efficiency. Relying solely on manual observation for measuring stack height can decrease harvesting efficiency and pose safety risks due to driver distraction. This research applies binocular vision to agricultural harvesting, proposing a novel method that uses a stereo matching algorithm to measure material pile height during harvesting. By comparing distance measurements taken in both empty and loaded states, the method determines stack height. A linear regression model processes the stack height data, enhancing measurement accuracy. A binocular vision system was established, applying Zhang’s calibration method on the MATLAB (R2019a) platform to correct camera parameters, achieving a calibration error of 0.15 pixels. The study implemented block matching (BM) and semi-global block matching (SGBM) algorithms using the OpenCV (4.8.1) library on the PyCharm (2020.3.5) platform for stereo matching, generating disparity, and pseudo-color maps. Three-dimensional coordinates of key points on the piled material were calculated to measure distances from the vehicle container bottom and material surface to the binocular camera, allowing for the calculation of material pile height. Furthermore, a linear regression model was applied to correct the data, enhancing the accuracy of the measured pile height. The results indicate that by employing binocular stereo vision and stereo matching algorithms, followed by linear regression, this method can accurately calculate material pile height. The average relative error for the BM algorithm was 3.70%, and for the SGBM algorithm, it was 3.35%, both within the acceptable precision range. While the SGBM algorithm was, on average, 46 ms slower than the BM algorithm, both maintained errors under 7% and computation times under 100 ms, meeting the real-time measurement requirements for combine harvesting. In practical operations, this method can effectively measure material pile height in transport vehicles. The choice of matching algorithm should consider container size, material properties, and the balance between measurement time, accuracy, and disparity map completeness. This approach aids in manual adjustment of machinery posture and provides data support for future autonomous master-slave collaborative operations in combine harvesting.

Study on cavitation erosion mechanism of UHMWPE and PTFE

Polymer materials possess low density, high strength, corrosion resistance, and excellent cavitation erosion resistance. As a result, they are widely used in marine, water conservancy, and other engineering equipment as replacements for metal materials. However, polymer friction pairs working in a water environment for an extended period are easily damaged by cavitation erosion. In this work, the cavitation behavior of polytetrafluoroethylene (PTFE) and ultra-high molecular weight polyethylene (UHMWPE) in deionized water and seawater is investigated through experiments and computational fluid dynamics (CFD) simulations. The results indicate that the cavitation erosion resistance of UHMWPE is significantly better than that of PTFE, and the UHMWPE has four cavitation process stages, while the PTFE has only three cavitation stages. 316L counterparts in the seawater corrosion and cavitation coupling effect of a large number of metal particles off and wash polymer material surface, so that the cavitation erosion of PTFE and UHMWPE is more serious in seawater environment. CFD simulation demonstrates that the cavitation erosion zone under the radiator shows a semicircular distribution. Meanwhile, the formation of ring-shaped cavitation pit is related to the distribution of bubbles on the surface of the radiator. The cavitation rate of PTFE and UHMWPE is slowed down by the “water cushion effect”.

COMPUTER SIMULATION OF ELECTRICALLY CONDUCTING PROPERTIES OF MATERIAL FOR PERSONAL PROTECTION EQUIPMENT

The article presents an analysis of production factors that have a harmful effect on the health of workers. It has been established that one of the leading factors is an increased electrostatic field that occurs when a static charge accumulates on the surface of materials. An increased level of the electrostatic field can lead to various negative consequences for workers’ health. For full antistatic protection at work, not only special tools and workplaces are needed, but also special footwear made of conductive materials with high surface resistance, as well as other personal protective equipment. A computer model for simulating the occurrence and development of an electrical breakdown in a protective material for personal protective equipment is described. The model is based on energy concepts of the occurrence and development of a discharge, taking into account the statistical heterogeneity of the material’s electrical conductivity. The process of breakdown development is considered as a special case of the percolation effect and a branching random process. The model makes it possible to find a relationship between the heterogeneity of the material and the threshold of its protective properties.

Physics-Informed Neural Networks-Based Online Excavation Trajectory Planning for Unmanned Excavator

As a large-scale mining excavator, the electric shovel (ES) has been extensively employed in open-pit mines for overburden removal and mineral loading. In the development of unmanned operations for ES, dynamic excavation trajectory planning is essential, as it directly influences operational efficiency and energy consumption by guiding the dipper during excavation. However, conventional optimization-based methods for excavation trajectory planning typically start from scratch, resulting in a time-consuming process that fails to meet real-time requirements. To address this challenge, we propose an innovative online trajectory planning framework based on physics-informed neural networks (PINNOTP) that utilizes advanced data-driven techniques. The input to PINNOTP consists of on-site working conditions, including the initial state of the ES and the material surface being excavated. The output is a smooth, polynomial-based curve that serves as the reference trajectory for the dipper. To ensure smooth execution of the generated trajectory, prior domain knowledge—such as physics-based target-oriented constraints, essential system dynamics, and mechanical constraints—is explicitly incorporated into the loss function during training. A case study is presented to validate the proposed method, demonstrating that PINNOTP effectively addresses the challenges of online excavation trajectory planning.