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Dongxia Li,Kuikui Ni,Yingchao Zhang,Yanli Lin,Fuyu Yang 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.5
Objective: In tropical regions, as in temperate regions where seasonality of forage production occurs, well-preserved forage is necessary for animal production during periods of forage shortage. However, the unique climate conditions (hot and humid) and forage characteristics (high moisture content and low soluble carbohydrate) in the tropics make forage preservation more difficult. The current study used natural ensiling of tropical forage as a model to evaluate silage characteristics under different temperatures (28°C and 40°C). Methods: Four tropical forages (king grass, paspalum, white popinac, and stylo) were ensiled under different temperatures (28°C and 40°C). After ensiling for 30 and 60 days, samples were collected to examine the fermentation quality, chemical composition and microbial community. Results: High concentrations of acetic acid (ranging from 7.8 to 38.5 g/kg dry matter [DM]) were detected in silages of king grass, paspalum and stylo with relatively low DM (ranging from 23.9% to 30.8% fresh material [FM]) content, acetic acid production was promoted with increased temperature and prolonged ensiling. Small concentrations of organic acid (ranging from 0.3 to 3.1 g/kg DM) were detected in silage of white popinac with high DM content (50.8% FM). The microbial diversity analysis indicated that Cyanobacteria originally dominated the bacterial community for these four tropical forages and was replaced by Lactobacillus and Enterobacter after ensiling. Conclusion: The results suggested that forage silages under tropical climate conditions showed enhanced acetate fermentation, while high DM materials showed limited fermentation. Lactobacillus and Enterobacter were the most probable genera responsible for tropical silage fermentation.
Research on Preparation Methods of Ultrafine Softwood Powder
Changsheng Fan,Dongxia Yang,Hongling Wang,Yan Sun,Hua lou,Hongru Yang 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.4
Pine wood sawdust is used as raw materials for experimental processing into ultrafine wood powder. Sizes of ultrafine wood powder particles serve as a standard for measuring ultrafine processing. The core part of the experimental processing equipment is the millstone which can exert great shear force and grinding force on strong fiber materials so as to ensure the successful preparation of ultrafine particles. The “equilibrium orbit” model is used to simulate processed superfine particles in calculating separation performance. Moreover, the CFD is chosen for simulating separation performance of wood powder particles with different sizes in the two-phase flow field, so as to ensure the successful separation and grading of wood powder particles with different sizes in the practical processing. Research is made on physical properties of collected wood powder as samples with different sizes and influence on composite material properties when ultrafine wood powder is taken as padding. Research on ultrafine wood powder provides meaningful experimental data and theoretical support for the future research on micro-nano fibrils.