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PORK PRODUCTION SYSTEMS IN CHINA:A REVIEW OF THEIR DEVELOPMENT,CHALLENGES AND PROSPECTS IN GREEN PRODUCTION

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Frontiers of Agricultural science and engineering 2021年第1期8卷 15-24页

作者： Shuai ZHANG Xin WU Dandan HAN Yong HOU Jianzhuang TAN Sung Woo KIM Defa LI Yulong YIN Junjun WANG State Key Laboratory of Animal Nutrition Ministry of Agriculture and Rural Affairs Feed Industry CentreCollege of Animal Science and TechnologyChina Agricultural UniversityBeijing 100193China Key Laboratory of Agro-ecological Processes in the Subtropical Region Institute of Subtropical Agriculturethe Chinese Academy of SciencesNational Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry ProductionHunan Provincial Engineering Research Center for Healthy Livestock and Poultry ProductionScientific Observation and Experimental Station of Animal Nutrition and Feed Science in the South-Central RegionMinistry of Agriculture and Rural AffairsChangsha 410125China College of Resources and Environmental Sciences National Academy of Agriculture Green DevelopmentKey Laboratory of Plant-Soil Interactions(Ministry of Education)China Agricultural UniversityBeijing 100193China Tech-bank Food Co. LtdNanjing 211800China Department of Animal Science College of Agriculture and Life SciencesNorth Carolina State UniversityRaleighNC 27695USA

This paper reviews the changes in pork production in China,the largest pork producing and consuming nation in the *** pork sector in China has changed dramatically since the 1990s,with large-scale intensive pork production systems replacing the former,exclusively family-based pork production *** breeding,feeding,vaccinating,and management technologies are widely used ***,smallholders still account for a large proportion of the total *** intensification and specialization of the pork sector is expected to continue in the future,but there is increasing awareness and pressure to develop more environmentally-sustainable production *** relative shortage of domestically produced feed,the low utilization efficiency of feed ingredients,the large emissions of nitrogen and phosphorus to the environment,the high use of antibiotics,and the presence of residual metals in manures are very large challenges for the pork sector *** solve these problems,techniques including new feed resource utilization,precise feeding,low-protein diets,alternatives to antibiotics and increased manure recycling are all important topics and research directions *** new techniques and management approaches,it is possible to build more sustainable pork production systems in China.

关键词： China feed pork production sustainability

Collision-free trajectory planning for autonomous surface vehicle

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arXiv

arXiv 2020年

作者： Wen, Licheng Yan, Jiaqing Yang, Xuemeng Liu, Yong Gu, Yong College of Control Science and Technology Zhejiang University Hangzhou China State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and Control Zhejiang University Zhejiang310027 China

In this paper, we propose an efficient and accurate method for autonomous surface vehicles to generate a smooth and collision-free trajectory considering its dynamics constraints. We decouple the trajectory planning problem as a front-end feasible path searching and a back-end kinodynamic trajectory optimization. Firstly, we model the type of two-thrusts under-actuated surface vessel. Then we adopt a sampling-based path searching to find an asymptotic optimal path through the obstacle-surrounding environment and extract several waypoints from it. We apply a numerical optimization method in the back-end to generate the trajectory. From the perspective of security in the field voyage, we propose the sailing corridor method to guarantee the trajectory away from obstacles. Moreover, considering limited fuel ASV carrying, we design a numerical objective function which can optimize a fuel-saving trajectory. Finally, we validate and compare the proposed method in simulation environments and the results fit our expected trajectory. Copyright © 2020, The Authors. All rights reserved.

关键词： Autonomous vehicles

Effect of Mach number on gust-airfoil interaction noise 27

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Effect of Mach number on gust-airfoil interaction noise

27th International Congress on Sound and Vibration, ICSV 2021

作者： Jiang, Shujie Mao, Yijun Yan, Zhenguo Hu, Zhiwei Key lab of Aerodynamic Noise Control China Aerodynamics Research and Development Center Sichuan Mianyang621000 China Faculty of Engineering and Physical Sciences University of Southampton SouthamptonSO17 1BJ United Kingdom HuaZhong University of Science and Technology Wuhan430074 China State Key Laboratory of Aerodynamics Research and Development Center Mianyang China Department of Aeronautics Imperial College London London United Kingdom

ISBN: (纸本)9788378807995

Helicopter noise prediction is challenging because of the complex aerodynamic environment. Gust-airfoil interaction is a significant source of helicopter broadband noise. The noise generation mechanisms of gust-airfoil interaction are studied through numerical simulations solving the compressible Euler equations using a spectral/hp element method. The applied approach is verified by a transonic benchmark and a single airfoil gust response problem, with different mesh and different domain sizes, giving accurate prediction of the sound waves generated by gust-airfoil interaction. Simulations are then performed for gust with different frequencies interacting with NACA0012 at different angles of attack and at a wide range of Mach numbers (from subsonic to transonic). The sound intensity increases with similar directivities in the subsonic region. The exist of shock waves can affect both sound intensity and directivity dramatically. The maximum sound intensity generated by the interaction in transonic flow is much bigger than generated by subsonic flow. The directions of the maximum sound intensity are different for transonic flow and subsonic flow. In the transonic interaction, the maximum sound intensity is observed in the downstream direction, compared to upstream for subsonic flow. The gust frequency can play an important role in the scattering effect of shock waves. As the gust frequency increases, more lobes are generated in the radiated noise directivity. It is also observed that the angle of attack can change the directivity of the radiated sound which is different from the influence of Mach number. With the increase of angle of attack, stronger sound intensity is observed in the upstream direction with a weaker sound intensity in the downstream direction. © "Advances in Acoustics, Noise and Vibration - 2021" Proceedings of the 27th International Congress on Sound and Vibration, ICSV 2021. All rights reserved.

关键词： Airfoils

Enhancing Nitrate Removal Efficiency of Micro-Sized Zero-Valent Iron by Chitosan Gel Balls Encapsulating

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SSRN 2021年

作者： An, Facai Feng, Xianlu Dang, Yan Sun, Dezhi College of Environmental Science and Engineering Beijing Forestry University Beijing Key Laboratory for Source Control Technology of Water Pollution Engineering Research Center for Water Pollution Source Control and Eco-remediation Beijing Forestry University Beijing100083 China

The activity of micro-sized zero-valent iron (MZVI) material for nitrate removal in neutral pH and low C/N ratios water needs to be improved. In this study, micro-sized zero-valent iron@chitosan (MZVI@CS) material was synthesized through embedding MZVI particles into chitosan (CS) gel by sol-gel method, and was used for deep removal of NO3-N in the absence of organic carbon sources and neutral pH. The NO3- -N removal rate of MZVI@CS was 0.37 mg-N·L-1·d-1 (dosage of 1%, initial pH = 7, 25 oC, initial nitrate concentration = 15 mg-N·L-1), which was 11.33 times higher than that of MZVI. The apparent activation energy (Ea) of MZVI@CS with nitrate was 38.23 kJ·mol-1 . MZVI@CS can remove nitrate effectively at a low concentration (15 mg-N·L-1). A stable denitration rate (0.37-2.28 mg-N·L-1·d-1) could be maintained under weak acidic, neutral and alkaline conditions (pH = 5-9). More than 80% of reduced nitrate was converted to N2 , and only a small amount was converted to NH4+ or NO2- . The gel structure of MZVI@CS eliminated the agglomeration between MZVI particles while the forming of Fe-CS chelates reduced the formation of iron oxide and solved the problems of passivation, hence successfully strengthened the NO3-N removal efficiency of MZVI. Therefore MZVI@CS has great application potential in NO3-N deep removal of water bodies with neutral pH and low C/N ratios. © 2021, The Authors. All rights reserved.

关键词： Nitrates

An Optimize Adaptable Method for Determining the Monosaccharide Composition of Pectic Polysaccharides

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SSRN 2023年

作者： Wu, Jinghua Zhu, Kai Li, Junhui Hu, Xinxin Ye, Xingqian Chen, Shiguo College of Agriculture and Biotechnology Zhejiang University Zhejiang Hangzhou310058 China College of Biosystems Engineering and Food Science National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment Zhejiang Key Laboratory for Agro-Food Processing Integrated Research Base of Southern Fruit and Vegetable Preservation Technology Zhejiang International Scientific and Technological Cooperation Base of Health Food Manufacturing and Quality Control Zhejiang University Hangzhou310058 China Fuli Institute of Food Science Zhejiang University Hangzhou310058 China Ningbo Research Institute Zhejiang University Hangzhou315100 China

Monosaccharide composition analysis is an essential to characterize the structure and biological activities of complex polysaccharides. However, due to the acid-induced precipitates under the acidic condition, the incomplete hydrolysis is common in monosaccharide analysis of acidic polysaccharides (especially for pectin). The main aim of this paper is to provide an improved method for pectin’s monosaccharide analysis using optimized acid hydrolysis combined with high-performance anion exchange chromatography. Firstly, the acid-induced precipitates of pectin was remitted by reducing the concentration of samples to 0.5mg/mL. Then, the optimized hydrolysis condition was performed at 110 ℃ for 6 h with 2 mol/L TFA. Finally, five acidic polysaccharides from fruits were used to optimize and validate the method and showed the method’s reproducibility and ability to analyze complicated pectic polysaccharides. It suggests that this hydrolysis method could be applied to obtain accurate quantitation of monosaccharide composition analysis for acidic polysaccharides. © 2023, The Authors. All rights reserved.

关键词： Polysaccharides

Investigation of a New Type of Thermal Insulation Shotcrete with Silicone Rubber Tubes (Ssrt)

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SSRN 2021年

作者： Chen, Lianjun Meng, Xiangrui Liu, Guoming Zhao, Jipeng Liu, Zhaoxia College of Safety and Environmental Engineering Shandong University of Science and Technology Qingdao266590 China College of Energy and Mining Engineering Shandong University of Science and Technology Qingdao266590 China State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province Ministry of Science and Technology Shandong University of Science and Technology Qingdao266590 China

In order to solve the high temperature problem faced in underground engineering, a method of laying silicone rubber tubes (SRTs) in the anchor net structure to form a new type of thermal insulation shotcrete with SRTs (SSRT) is proposed in this paper. The mechanical and thermal insulation performances of SSRT are investigated, as well as the correlation between SRTs sizes and compressive strength, splitting strength and thermal conductivity. Results show that SSRT has increased the thermal insulation performance of 44%-71% compared with ordinary Portland shotcrete (OPS), and the mechanical performance is affected to varying degrees. Based on the experiments in this paper, the optimal SRTs laying process parameters of SSRT are determined, i.e. SRTs with an outer diameter of 8mm, an inter diameter of 3mm and a distance of 8mm-9mm between SRTs. This investigation provides a new exploration and theoretical basis for shotcrete support and insulation technology in high ground temperature environments. © 2021, The Authors. All rights reserved.

关键词： Thermal insulation

Hollow Cavity engineering of Mofs-Derived Hierarchical Mnox Structure for Highly Efficient Photothermal Degradation of Ethyl Acetate Under Visible Light Irradiation

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SSRN 2022年

作者： Li, Jun Mo, Shengpeng Ding, Xuegang Huang, Lili Zhoua, Xiaobin Fan, Yinming Zhang, Yanan Fu, Mingming Xie, Qinglin Ye, Daiqi College of Environment Science and Engineering Guilin University of Technology Guilin541004 China School of Environment and Energy South China University of Technology Guangzhou510006 China Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology Guilin University of Technology Guilin541004 China Guangxi Modern Industry College of Ecology and Environmental Protection Guilin541006 China

The designed synthesis of hollow-structure catalysts is central for enhancing the absorption and utilization of light irradiation, which is the core process of improved photothermal catalytic activity of VOCs. Herein, we introduced a viable cavity engineering for the fabrication of hollow MnOx-m architectures with a well-defined central space by in situ polyvinylpyrrolidone (PVP)-assisted Mn-BTC self-aggregation. The optimized MnOx-100 catalyst with hollow cavity environment exhibited approximately 96% ethyl acetate degradation toward CO2, stability and moisture resistance under visible light irradiation, which was much better than the traditional Mn-based MOFs derivatives (MOF-74-O and MIL-100-O). Combined experiment and DFT calculations, the more exposed Mn4+ sites in the MnOx-100 catalyst through a hollow cavity engineering could provide abundant adsorption sites, lower-temperature reducibility and narrower band gap, and its hollow structure endowed with significant advantages for photogenerated carrier separation efficiency and light absorption capacity. Finally, in situ DRIFTS results revealed that the introduction of light could change the possible reaction pathway of ethyl acetate degradation over the MnOx-100 catalyst, and aldehyde and ethylene were generated as by-products or non-critical intermediates under visible light irradiation. The main degradation pathway of ethyl acetate degradation occurred through ethyl acetate → ethanol and acetic acid → methanol and formic acid → CO2 and H2O. © 2022, The Authors. All rights reserved.

关键词： Carbon dioxide

Spatial-temporal Transformer for Skeleton-based Action Recognition

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Spatial-temporal Transformer for Skeleton-based Action Recog...

2021 China Automation Congress, CAC 2021

作者： Zhang, Qipeng Liu, Kexin Wang, Tian Shi, Peng Zhang, Mengyi Snoussi, Hichem School of Automation Science and Electrical Engineering Beihang University Beijing China Jiangsu Key Laboratory of Image and Video Understanding for Social Safety Nanjing University of Science and Technology Nanjing China Institute of Artificial Intelligence Beihang University Beijing China School of Mathematics and Computer Science Fujian Normal University Fujian China College of Electrical Engineering and Control Science Nanjing Tech University Nanjing China Institute Charles Delaunay-LM2S University of Technology of Troyes Troyes France

ISBN: (纸本)9781665426473

In the area of skeleton-based human action recognition, GCN has achieved good results in previous research due to its excellent modeling ability on graph data. Recently, transformers have achieved extraordinary results in many computer vision fields. Comparing transformer and GCN, from a certain point of view, we can regard transformer as a kind of dynamic GCN, and the weight of each node is dynamically determined by data. In this work, a three-dimensional position encoding was proposed by us to solve the representation of node spatial information, in order to apply the transformer to the graph data. In addition, similar to Spatial-Temporal Graph Convolutional Networks (ST-GCN), we proposed a Space-Time Transformer (ST-TR), which applies transformers in space and time to extract spatiotemporal feature of skeleton data to complete action recognition. © 2021 IEEE

关键词： Computer vision

Sulfur and Phosphorus Co-Doped Feconicrmn High-Entropy Alloys as Efficient Sulfion Oxidation Reaction Catalysts Enabling Self-Powered Asymmetric Seawater Electrolysis

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SSRN 2024年

作者： Yu, Zhipeng Boukhvalov, Danil W. Tan, Hao Xiong, Dehua Feng, Chuangshi Wang, Jingwei Wang, Wei Zhao, Yang Xu, Kaiyang Su, Weifeng Xiang, Xinyi Lin, Fei Huang, Haoliang Zhang, Fuxiang Zhang, Lei Meng, Lijian Liu, Lifeng Songshan Lake Materials Laboratory Dongguan523808 China College of Science Institute of Materials Physics and Chemistry Nanjing Forestry University Nanjing210037 China Institute of Physics and Technology Ural Federal University Mira Street 19 Yekaterinburg620002 Russia State Key Laboratory of Silicate Materials for Architectures Wuhan University of Technology Wuhan430070 China Centre of Innovation in Engineering and Industrial Technology Instituto Superior de Engenharia do Porto Instituto Politecnico do Porto Porto4249-015 Portugal International Iberian Nanotechnology Laboratory Portugal Sweden

Seawater electrolysis (SWE) represents a promising approach to green hydrogen (H2) production but currently faces substantial challenges such as the interference of chlorine chemistry and high energy consumption. In this work, we demonstrate that by replacing the energy-demanding oxygen evolution reaction with the sulfion oxidation reaction (SOR) and by implementing the concept of bipolar membrane (BPM) electrolysis in an acid-base dual electrolyte system, not only can the notorious chlorine evolution reaction (CER) be completely circumvented, but the energy consumption of SWE be significantly reduced. To do so, we develop a sulfur and phosphorus co-doped FeCoNiCrMn high entropy alloy (HEA-SP) catalyst, which shows good electrocatalytic performance for the SOR in alkaline-saline water. Density functional theory calculations and in situ Raman spectroscopy reveal the crucial role of imperfect sulfur coverage on the HEA in facilitating the formation of Sx clusters during the SOR. Moreover, self-powered SWE is also demonstrated. © 2024, The Authors. All rights reserved.

关键词： Entropy