We introduce Pixel-aligned Implicit Function (PIFu), an implicit representation that locally aligns pixels of 2D images with the global context of their corresponding 3D object. Using PIFu, we ...propose an end-to-end deep learning method for digitizing highly detailed clothed humans that can infer both 3D surface and texture from a single image, and optionally, multiple input images. Highly intricate shapes, such as hairstyles, clothing, as well as their variations and deformations can be digitized in a unified way. Compared to existing representations used for 3D deep learning, PIFu produces high-resolution surfaces including largely unseen regions such as the back of a person. In particular, it is memory efficient unlike the voxel representation, can handle arbitrary topology, and the resulting surface is spatially aligned with the input image. Furthermore, while previous techniques are designed to process either a single image or multiple views, PIFu extends naturally to arbitrary number of views. We demonstrate high-resolution and robust reconstructions on real world images from the DeepFashion dataset, which contains a variety of challenging clothing types. Our method achieves state-of-the-art performance on a public benchmark and outperforms the prior work for clothed human digitization from a single image.
Damage to mechanical components caused by contaminant ingress is a common failure. In response to this issue, this study introduces a synergistic abrasion reduction method based on the combined ...application of ceramic materials and surface texturing. Using cylindrical thrust roller bearings as an illustration, circular textures were applied to the raceways, and a small number of steel rollers were substituted with ceramic ones. Moreover, alumina was introduced into the lubricant as a contaminant. The frictional and dynamic performance of the "ceramic-textured surface" combination under lubricant contamination conditions was explored and compared with corresponding single abrasion reduction techniques. The synergistic abrasion reduction mechanism of the "ceramic-textured surface" combination was also examined. The findings reveal that under lubricant contamination conditions, the synergistic abrasion reduction method surpasses individual abrasion reduction methods and demonstrates a certain degree of complementarity. Compared with traditional all-steel bearings, textured bearings with four ceramic rollers have reduced the average frictional force by approximately 56.82 %, and the mass loss of the shaft washer and seat washer has been reduced by approximately 81.01 % and 80.86 %, respectively. Rolling elements treated with the synergistic abrasion reduction method exhibit enhanced resistance to abrasive particle wear. This improvement is attributed to the collaborative effects of various mechanisms, including crushing and refinement, capture and storage, grinding and finishing, as well as self-healing and smoothing.
•A synergistic wear reduction method to reduce abrasive wear is proposed.•Abrasive wear tests were carried out under rolling conditions.•The surface texture and ceramic materials are added to the rolling bearing as anti-wear measures.•The tribological behavior and dynamic performance of the synergistic anti-wear method were evaluated.•The synergistic wear reduction method exhibits better wear resistance.
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Surface texture plays an important role in reducing friction, which has been widely applied in mechanical equipment. In this paper, a surface texture design method for sliding friction pairs based on ...machine learning is proposed, which consists of three parts: model training and construction, texture design and result verification. Firstly, artificial neural network (ANN) and gradient boosting decision tree (GBDT) are selected as the optimal forward and reverse models respectively by comparing five machine learning models. Then the optimal forward and reverse models are combined to design surface texture and verify the design results. The results show that the combination of forward and reverse models is reliable. Lubricant viscosity and friction coefficient obviously affect the design of texture size, depth and coverage. Finally, the feasibility and effectiveness of this method are validated by friction experiments. The results provide a new approach for the design of surface texture.
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Tibetan Plateau is known as the world’s third pole, which is characterized by a low population density with very limited human activities. Tibetan Plateau possesses the greatest numbers of ...high-altitude inland lakes in the world. However, no information is currently available on the characteristic of microplastic pollution in those lakes within this remote area. In this work, lakeshore sediments from four lakes within the Siling Co basin in northern Tibet were sampled and examined for microplastics (<5 mm). Microplastics were detected in six out of seven sampling sites with abundances ranging from 8 ± 14 to 563 ± 1219 items/m2. Riverine input might have contributed to the high abundance of microplastics observed in this remote area. Morphological features suggest that microplastics are derived from the breakdown of daily used plastic products. Polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyvinyl chloride were identified from the microplastic samples using laser Raman spectroscopy, and oxidative and mechanical weathering textures were observed on the surface of microplastics using scanning electron microscope. These results demonstrate the presence of microplastics even for inland lakes in remote areas under very low human impact, and microplastic pollution can be a global issue.
•Microplastics were presented in lakeshore sediments from remote lakes in Tibet Plateau.•Microplastics were detected with an average abundance up to 563 items/m2.•PE, PP, PET, PVC and PS were identified from the microplastic samples.•Surface texture of microplastics show mechanical and oxidative weathering features.
Remote lakes in Tibet Plateau were found polluted by microplastics.
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Scale/scaly structures are commonly seen in living nature, such as loach and pangolin, and they generally play an important role in reducing friction between biosurfaces and their contacted ...solid/water. Hence, inspired by scale structures in biology, we propose a design of surface texturing with 3D delicate scaly structures to improve the tribological behaviors of mechanical friction interfaces under starved lubrication. Micro 3D metal printing technology was employed to fabricate the scaly textured surface. Experimental tests were performed and the results demonstrated the favorable effect of such bionic texturing on reducing friction coefficient and wear. Furthermore, corresponding FEM simulations and high-speed camera observation confirmed the amplification effect of secondary lubrication and the pre-lubrication effect as the dominating mechanisms.
•A bioinspired 3D scaly surface texturing was designed and fabricated.•Friction coefficient reduction effect of the 3D textures was demonstrated.•Amplification of secondary lubrication and the pre-wetting effect were deduced as the main mechanism.
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We introduce a method for learning to generate the surface of 3D shapes. Our approach represents a 3D shape as a collection of parametric surface elements and, in contrast to methods generating voxel ...grids or point clouds, naturally infers a surface representation of the shape. Beyond its novelty, our new shape generation framework, AtlasNet, comes with significant advantages, such as improved precision and generalization capabilities, and the possibility to generate a shape of arbitrary resolution without memory issues. We demonstrate these benefits and compare to strong baselines on the ShapeNet benchmark for two applications: (i) autoencoding shapes, and (ii) single-view reconstruction from a still image. We also provide results showing its potential for other applications, such as morphing, parametrization, super-resolution, matching, and co-segmentation.
Surface texture technology is crucial for reducing the friction coefficient of contact surface and enhancing friction performance. Based on the research into the role of texture in reducing friction, ...this paper examines the mechanism and performance influencing factors of textured surfaces in reducing friction, and it provides an overview of the effects of textured shape, sliding speed, textured density, depth, and other factors on friction performance. By contrasting composite texture processing with single texture processing and the current status of research, the potential research directions for enhanced friction performance are presented.
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To understand the research status of asphalt pavement texture, the related achievements and progress of pavement surface texture were systematically sorted out from three aspects: the ...characterization of pavement surface texture, the texture measurement and evaluation, and the relationship between texture and the skid resistance. Based on the statistical geometric characteristics, the spectral characteristics, the fractal characteristics and the multifractal characteristics, the characteristics of pavement texture were discussed. The test methods of pavement texture were divided into two categories: direct measurement methods and indirect measurement methods. The advantages and disadvantages of each measurement method were summarized. The effects of macro-texture and micro-texture on asphalt pavement were discussed, respectively. The relationship between texture and skid resistance was studied. This review shows that multifractal theory should be further studied from the aspect of road engineering. High-precision non-contact integrated detection technology should be further studied to meet the needs of complex testing environments. The method of finite element numerical simulation has potential for the analysis of pavement skid resistance. In addition, methods such as big data analysis, neural network, and deep learning should be studied to achieve the intelligent perception and management of the whole state of skid resistance prediction.
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