Background:During the production of tea,tea dust has been viewed as a risk factor that may cause the suffering of changes of lung function and respiratory symptoms.Objective:To review whether the occupational exposure...Background:During the production of tea,tea dust has been viewed as a risk factor that may cause the suffering of changes of lung function and respiratory symptoms.Objective:To review whether the occupational exposure to tea dust may lead to the changes of lung function and respiratory symptoms.Methods:We searched the literatures in March 2012 in the databases of Medline,EMBase,Web of Science,Wan-Fang Database and CNKI.The search condition is"(herb OR tea)AND(lung function OR ventilatory function OR pulmonary function OR spirometric measurement)".The paper should be pubished in Enghish or Chinese,with internal or external controls.Results:Totally 17 papers were included.Both acute and chronic changes of lung function were referred.In addition,the respiratory symptoms such as cough,tightness and etc.were also reported and discussed.Conclusion:We concluded that the exposure of tea dust may lead to the changes of lung function and respiratory symptoms.展开更多
为解决沙棘叶茶茶毫离散元仿真中缺乏准确接触参数的问题,利用物理和仿真休止角堆积试验标定茶毫接触参数;将茶毫颗粒简化为软质球形颗粒,通过量纲分析和颗粒缩放理论将茶毫空气动力学当量粒径从231.37μm放大至1.8 mm。利用EDEM软件,...为解决沙棘叶茶茶毫离散元仿真中缺乏准确接触参数的问题,利用物理和仿真休止角堆积试验标定茶毫接触参数;将茶毫颗粒简化为软质球形颗粒,通过量纲分析和颗粒缩放理论将茶毫空气动力学当量粒径从231.37μm放大至1.8 mm。利用EDEM软件,选定“Hertz–Mindlin with JKR”接触模型,以休止角为响应值,通过Plackett-Burman试验筛选出对休止角影响最显著的3个参数:茶毫-茶毫恢复系数、茶毫-茶毫滚动摩擦系数、茶毫-不锈钢滚动摩擦系数;利用最陡爬坡试验,确定各参数最佳取值范围;根据Box-Behnken试验建立并优化3个显著性参数与休止角的二阶回归方程,对回归方程进行寻优求解。得到3个显著性参数的最优组合:茶毫-茶毫恢复系数为0.159,茶毫-茶毫滚动摩擦系数为0.290,茶毫-不锈钢滚动摩擦系数为0.239。通过对比休止角仿真试验值与物理试验值,二者相对误差为1.97%,表明仿真试验预测效果良好。展开更多
文摘Background:During the production of tea,tea dust has been viewed as a risk factor that may cause the suffering of changes of lung function and respiratory symptoms.Objective:To review whether the occupational exposure to tea dust may lead to the changes of lung function and respiratory symptoms.Methods:We searched the literatures in March 2012 in the databases of Medline,EMBase,Web of Science,Wan-Fang Database and CNKI.The search condition is"(herb OR tea)AND(lung function OR ventilatory function OR pulmonary function OR spirometric measurement)".The paper should be pubished in Enghish or Chinese,with internal or external controls.Results:Totally 17 papers were included.Both acute and chronic changes of lung function were referred.In addition,the respiratory symptoms such as cough,tightness and etc.were also reported and discussed.Conclusion:We concluded that the exposure of tea dust may lead to the changes of lung function and respiratory symptoms.
文摘为解决沙棘叶茶茶毫离散元仿真中缺乏准确接触参数的问题,利用物理和仿真休止角堆积试验标定茶毫接触参数;将茶毫颗粒简化为软质球形颗粒,通过量纲分析和颗粒缩放理论将茶毫空气动力学当量粒径从231.37μm放大至1.8 mm。利用EDEM软件,选定“Hertz–Mindlin with JKR”接触模型,以休止角为响应值,通过Plackett-Burman试验筛选出对休止角影响最显著的3个参数:茶毫-茶毫恢复系数、茶毫-茶毫滚动摩擦系数、茶毫-不锈钢滚动摩擦系数;利用最陡爬坡试验,确定各参数最佳取值范围;根据Box-Behnken试验建立并优化3个显著性参数与休止角的二阶回归方程,对回归方程进行寻优求解。得到3个显著性参数的最优组合:茶毫-茶毫恢复系数为0.159,茶毫-茶毫滚动摩擦系数为0.290,茶毫-不锈钢滚动摩擦系数为0.239。通过对比休止角仿真试验值与物理试验值,二者相对误差为1.97%,表明仿真试验预测效果良好。
