Die filling is a critical stage during powder compaction,which can significantly affect the product quality and efficiency.In this paper,a forced feeder is introduced attempting to improve the filling performance of a...Die filling is a critical stage during powder compaction,which can significantly affect the product quality and efficiency.In this paper,a forced feeder is introduced attempting to improve the filling performance of a lab-scale die filling system.The die filling process is analysed with a graphics processing units(GPU)enhanced discrete element method(DEM).Various stirrer designs are assessed for a wide range of process settings(i.e.,stirrer speed,filling speed)to explore their influence on the die filling performance of free-flowing powder.Numerical results show that die filing with the novel helical-ribbon(i.e.,type D)stirrer design exhibits the highest filling ratio,implying that it is the most robust stirrer design for the feeder configuration considered.Furthermore,die filling performance with the type D stirrer design is a function of the stirrer speed and the filling speed.A positive variation of filling ratio(ηf>0%)can be ensured over the whole range of filling speed by adjusting the stirrer speed(i.e.,increasing the stirrer speed).The approach used in this study can not only help understand how the stirrer design affects the die filling performance but also guide the optimization of feeder system and process settings.展开更多
目的分析家庭喂养方式与2~6岁儿童营养不足的关系,为指导科学喂养儿童提供支持,并为儿童营养不足的干预提供参考。方法采用多阶段抽样方法,于2021年选取安徽省合肥市幼儿园在园儿童3655例为研究对象,并对其家长进行问卷调查,问卷内容包...目的分析家庭喂养方式与2~6岁儿童营养不足的关系,为指导科学喂养儿童提供支持,并为儿童营养不足的干预提供参考。方法采用多阶段抽样方法,于2021年选取安徽省合肥市幼儿园在园儿童3655例为研究对象,并对其家长进行问卷调查,问卷内容包括儿童和家长的一般情况及儿童喂养问卷。该问卷用于评估家长在儿童喂养方面的行为和信念,重点调查涉及父母喂养方式的3个维度,即限制进食、逼迫进食和监督进食,共12个条目。通过建立多因素logistic回归模型分析家庭喂养方式与儿童营养不足的关系。结果安徽省合肥市2021年秋季幼儿园在园2~6岁儿童营养不足检出率为3.09%。家长采用监督的喂养方式看护的儿童营养不足检出率低于家长采用非监督的喂养方式(χ^(2)=6.672,P=0.010);家长采用逼迫的喂养方式看护的儿童营养不足检出率高于家长采用非逼迫的喂养方式(χ^(2)=14.008,P<0.001);家长是否采用限制的喂养方式照护下的儿童营养不足检出率比较差异无统计学意义(χ^(2)=0.001,P=0.974)。调整性别、出生体重、父亲体质指数(body mass index,BMI)、母亲BMI、父亲文化水平等混杂因素,家长采用监督的喂养方式是儿童营养不足的保护因素[OR(95%CI)=0.633(0.430~0.932),P=0.020];家长采用逼迫的喂养方式是儿童营养不足的危险因素[OR(95%CI)=2.104(1.328~3.335),P=0.002]。结论家庭喂养方式与2~6岁儿童营养不足发生情况有关,应提倡家长采用科学合理的喂养方式,尽最大可能降低儿童营养不足发生的风险。展开更多
基金the financial support from Genentech Ltd.,the Engineering and Physical Science Research Council(Grant No.EP/M02976X)the Marie Skłodowska-Curie Individual Fellowships under European Union's Horizon 2020 research and innovation programme(Grant No.840264)。
文摘Die filling is a critical stage during powder compaction,which can significantly affect the product quality and efficiency.In this paper,a forced feeder is introduced attempting to improve the filling performance of a lab-scale die filling system.The die filling process is analysed with a graphics processing units(GPU)enhanced discrete element method(DEM).Various stirrer designs are assessed for a wide range of process settings(i.e.,stirrer speed,filling speed)to explore their influence on the die filling performance of free-flowing powder.Numerical results show that die filing with the novel helical-ribbon(i.e.,type D)stirrer design exhibits the highest filling ratio,implying that it is the most robust stirrer design for the feeder configuration considered.Furthermore,die filling performance with the type D stirrer design is a function of the stirrer speed and the filling speed.A positive variation of filling ratio(ηf>0%)can be ensured over the whole range of filling speed by adjusting the stirrer speed(i.e.,increasing the stirrer speed).The approach used in this study can not only help understand how the stirrer design affects the die filling performance but also guide the optimization of feeder system and process settings.
文摘目的分析家庭喂养方式与2~6岁儿童营养不足的关系,为指导科学喂养儿童提供支持,并为儿童营养不足的干预提供参考。方法采用多阶段抽样方法,于2021年选取安徽省合肥市幼儿园在园儿童3655例为研究对象,并对其家长进行问卷调查,问卷内容包括儿童和家长的一般情况及儿童喂养问卷。该问卷用于评估家长在儿童喂养方面的行为和信念,重点调查涉及父母喂养方式的3个维度,即限制进食、逼迫进食和监督进食,共12个条目。通过建立多因素logistic回归模型分析家庭喂养方式与儿童营养不足的关系。结果安徽省合肥市2021年秋季幼儿园在园2~6岁儿童营养不足检出率为3.09%。家长采用监督的喂养方式看护的儿童营养不足检出率低于家长采用非监督的喂养方式(χ^(2)=6.672,P=0.010);家长采用逼迫的喂养方式看护的儿童营养不足检出率高于家长采用非逼迫的喂养方式(χ^(2)=14.008,P<0.001);家长是否采用限制的喂养方式照护下的儿童营养不足检出率比较差异无统计学意义(χ^(2)=0.001,P=0.974)。调整性别、出生体重、父亲体质指数(body mass index,BMI)、母亲BMI、父亲文化水平等混杂因素,家长采用监督的喂养方式是儿童营养不足的保护因素[OR(95%CI)=0.633(0.430~0.932),P=0.020];家长采用逼迫的喂养方式是儿童营养不足的危险因素[OR(95%CI)=2.104(1.328~3.335),P=0.002]。结论家庭喂养方式与2~6岁儿童营养不足发生情况有关,应提倡家长采用科学合理的喂养方式,尽最大可能降低儿童营养不足发生的风险。
