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.
Understanding the influence of surface properties (roughness, grooves, discrete textures/dimples) on the performance of hydrodynamically lubricated contacts has been the aim of numerous studies. A ...variety of different numerical models have been employed by many researchers in order to find optimal texturing parameters (shape, size, distribution) for best performance enhancement in terms of load carrying capacity, film thickness, friction and wear. However, the large number of different modeling techniques and complexity in the patterns make finding the optimum texture a challenging task and have led to contrary conclusions. This article outlines the research effort on surface texturing worldwide, reviews the key findings and, in particular, provides a comparative summary of different modeling techniques for fluid flow, cavitation and micro-hydrodynamic effects.
•This article facilitates the application of textures for hydrodynamic contacts.•Functions of surface textures, texture design and modeling techniques are discussed.•Textures must be designed for a given application and range of operating conditions.•Robust models allow the evaluation of texture designs prior to being manufactured.•The three major challenges in numerical modeling are discussed.
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.
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.
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.
•This paper reviews surface texture metrology literature for metal additively manufactured parts.•AM processes and materials used in the literature are presented.•The types of surfaces, measurement ...technologies and strategies employed are analysed.•Data processing, filtering and surface characterisation are discussed.
A comprehensive analysis of literature pertaining to surface texture metrology for metal additive manufacturing has been performed. This review paper structures the results of this analysis into sections that address specific areas of interest: industrial domain; additive manufacturing processes and materials; types of surface investigated; surface measurement technology and surface texture characterisation. Each section reports on how frequently specific techniques, processes or materials have been utilised and discusses how and why they are employed. Based on these results, possible optimisation of methods and reporting is suggested and the areas that may have significant potential for future research are highlighted.
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