How different factors and techniques affect concentration and generation of dust in a floor housing system for laying hens was investigated in a climate chamber. The efficiencies of different dust reducing measures we...How different factors and techniques affect concentration and generation of dust in a floor housing system for laying hens was investigated in a climate chamber. The efficiencies of different dust reducing measures were investigated. A major part of the generated dust settled on different surfaces inside the building. The settling rate of dust was affected by the concentration of dust in the air. The settled amount of dust also stood in relation to the floor area of the stable. An increased ventilation rate had a limited effect on the concentration of total dust due to the importance of the settling of the dust. The generation of dust was also investigated when using six different bedding materials, namely： gravel, clay pellets, peat, wood shavings, chopped straw and chopped paper. Clay pellets and peat resulted in the lowest concentrations of dust. Automatic spraying of small droplets of water reduced the dust concentration in four trials with different bedding materials （chopped paper, clay pellets, peat and wood shavings）. Spraying a mixture of rapeseed oil in water was also effective with an automatic spraying system.展开更多
文摘利用改进的渗透装置试验研究了细颗粒(0.075~1 mm)含量相同时骨架颗粒组成含量不同对散粒土的管涌发生临界条件以及颗粒侵蚀流失规律的影响,结果表明:不同颗粒级配的试样在管涌发生前,水力梯度与渗流速度呈线性关系,基本符合达西定律;骨架颗粒1~2、2~3、3~5 mm 3个粒径段对管涌发展起到了阻碍作用,其中1~2 mm粒径段颗粒对管涌孔隙的堵塞作用强于另外两个粒径段颗粒;对于不同级配的骨架颗粒,其不均匀系数越大,试样的下限临界水力梯度值就越大,细颗粒越不易起动,发生管涌的时间越晚,而不同级配的骨架颗粒对试样的上限临界水力梯度影响较小。
文摘How different factors and techniques affect concentration and generation of dust in a floor housing system for laying hens was investigated in a climate chamber. The efficiencies of different dust reducing measures were investigated. A major part of the generated dust settled on different surfaces inside the building. The settling rate of dust was affected by the concentration of dust in the air. The settled amount of dust also stood in relation to the floor area of the stable. An increased ventilation rate had a limited effect on the concentration of total dust due to the importance of the settling of the dust. The generation of dust was also investigated when using six different bedding materials, namely： gravel, clay pellets, peat, wood shavings, chopped straw and chopped paper. Clay pellets and peat resulted in the lowest concentrations of dust. Automatic spraying of small droplets of water reduced the dust concentration in four trials with different bedding materials （chopped paper, clay pellets, peat and wood shavings）. Spraying a mixture of rapeseed oil in water was also effective with an automatic spraying system.
