Under forced ventilation,the dust diffusion of underground powerhouse construction is investigated using a 3D high Reynolds number k-ε model.The interfacial momentum transfers and the wall roughness in the wall funct...Under forced ventilation,the dust diffusion of underground powerhouse construction is investigated using a 3D high Reynolds number k-ε model.The interfacial momentum transfers and the wall roughness in the wall function are considered.Ventilation in the third layer of underground powerhouse of Xiangjiaba hydropower station is used as a case.The geometric structure has a decisive effect on the airflow distribution.It is concluded that the dust concentration decreases gradually with the increase of the ventilation time.However,iso-concentration curves have the same tendency after 1 800 s.The dust concentration meets the ventilation and dust-prevention health standard after 2 300 s.The prediction by the present model is confirmed by the experimental measurement by Nakayama.展开更多
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
分享了海沃氏使用先进涂装设备提高生产效率的经验:快速换色粉房ColorMax系统的使用使整个换色时间由1 h减少到4 min 20 s,Encore粉末喷枪的应用克服了传统喷枪存在的粉末涂出量、带电效果及雾化效果不稳定的问题,单级回收粉房的应用使...分享了海沃氏使用先进涂装设备提高生产效率的经验:快速换色粉房ColorMax系统的使用使整个换色时间由1 h减少到4 min 20 s,Encore粉末喷枪的应用克服了传统喷枪存在的粉末涂出量、带电效果及雾化效果不稳定的问题,单级回收粉房的应用使粉末上粉率达到98%以上。新设备工艺技术的使用在提升产品品质的同时有效地控制了生产成本。展开更多
基金Supported by Natural Science Fund ation for Major Research Plan of China (No.90815019)National Natural Science Foundation of China (No.50879053)National Key Project of Scientific and Technical Supporting Programs Funded by Ministry of Science and Technology of China (No.2006BAB04A13)
文摘Under forced ventilation,the dust diffusion of underground powerhouse construction is investigated using a 3D high Reynolds number k-ε model.The interfacial momentum transfers and the wall roughness in the wall function are considered.Ventilation in the third layer of underground powerhouse of Xiangjiaba hydropower station is used as a case.The geometric structure has a decisive effect on the airflow distribution.It is concluded that the dust concentration decreases gradually with the increase of the ventilation time.However,iso-concentration curves have the same tendency after 1 800 s.The dust concentration meets the ventilation and dust-prevention health standard after 2 300 s.The prediction by the present model is confirmed by the experimental measurement by Nakayama.
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.
文摘分享了海沃氏使用先进涂装设备提高生产效率的经验:快速换色粉房ColorMax系统的使用使整个换色时间由1 h减少到4 min 20 s,Encore粉末喷枪的应用克服了传统喷枪存在的粉末涂出量、带电效果及雾化效果不稳定的问题,单级回收粉房的应用使粉末上粉率达到98%以上。新设备工艺技术的使用在提升产品品质的同时有效地控制了生产成本。
