Effect of several complex inoculants on mechanical properties, process-ability and sensibility of grey cast iron used in cylinder block were investigated. The experimental results showed that the grey cast iron treate...Effect of several complex inoculants on mechanical properties, process-ability and sensibility of grey cast iron used in cylinder block were investigated. The experimental results showed that the grey cast iron treated with 60%FeSi75+40%RE complex inoculants has tensile strength consistently at about 295 MPa along with good hardness and improved metallurgy quality. While the grey cast iron inoculated with 20%FeSi75+80%Sr compound inoculants has the best process-ability, the lowest cross-section sensibility and the least microhardness difference. The wear amount of the drill increases correspondingly with the increase of the microhardness difference of matrix structure, indicating the great effect of homogeneousness of matrix structure in the grey cast iron on the machinability of the grey cast iron.展开更多
<b><span style="font-family:Verdana;">Introduction: </span></b><span style="font-family:Verdana;">It is estimated that about 18% of pregnant women suffer from iron def...<b><span style="font-family:Verdana;">Introduction: </span></b><span style="font-family:Verdana;">It is estimated that about 18% of pregnant women suffer from iron deficiency anemia throughout their whole pregnancy.</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">In </span><span style="font-family:Verdana;">twin</span><span style="font-family:Verdana;"> pregnancy, owing to the relatively greater </span><span style="font-family:Verdana;">feto-placental</span><span style="font-family:Verdana;"> requirements and greater expansion in maternal plasma volume </span></span><span style="font-family:Verdana;">and red cell mass, iron requirements </span><span style="font-family:""><span style="font-family:Verdana;">are magnified 1.8 times compared to singleton pregnancies. However, for </span><span style="font-family:Verdana;">prevention</span><span style="font-family:Verdana;"> of iron deficiency in twin </span><span style="font-family:Verdana;">pregnancy</span><span style="font-family:Verdana;">, only sparse data exist regarding the sufficiency of the standard antenatal iron supplementation dose used in singleton pregnancies to meet the increased iron demand. In this study, we investigate the effect of single and double dose iron supplementation for </span><span style="font-family:Verdana;">prevention</span><span style="font-family:Verdana;"> of iron deficiency anemia in twin pregnancy. </span><b><span style="font-family:Verdana;">Methods: </span></b><span style="font-family:Verdana;">A randomized controlled clinical trial was conducted at our center in the period between February 2019 and October 2020,</span></span><span style="font-family:Verdana;"> and</span><span style="font-family:""> <span style="font-family:Verdana;">included</span><span style="font-family:Verdana;"> 450 eligible healthy non-anemic women aged 18 </span></span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;"> 35 years, with twin pregnancy at 12 </span><span style="font-family:Verdana;">-</span><span style="font-family:""><span style="font-family:Verdana;"> 16 weeks of gestation. After informed consent, eligible women were randomized to receive either single dose 27 mg, or double dose 54 mg elemental iron supplementation. Monitoring of hemoglobin concentration was done at fixed time points during gestation: at enrollment, 24 weeks, 32 weeks </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> before delivery. The primary outcome of the study was the incidence of iron deficiency anemia during </span><span style="font-family:Verdana;">follow up</span><span style="font-family:Verdana;"> until delivery. </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">The incidence of iron deficiency anemia in the two groups did not differ significantly between the </span><span style="font-family:Verdana;">single dose</span><span style="font-family:Verdana;"> group (19.1%) and the double dose group (24.0%). In women who did not develop Iron Deficiency Anemia, hemoglobin concentration varied significantly along the different gestational ages during the </span><span style="font-family:Verdana;">follow up</span><span style="font-family:Verdana;"> pe</span><span><span style="font-family:Verdana;">riod. In contrast, they did not show </span><span style="font-family:Verdana;">an overall statistically significant difference</span></span><span style="font-family:Verdana;"> in the hemoglobin concentrations between the single or double dose groups. </span><b><span style="font-family:Verdana;">Conclusion:</span></b> <span style="font-family:Verdana;">This</span><span style="font-family:Verdana;"> clinical trial did not demonstrate an added benefit for doubling prophylactic iron supplementation dose in non-anemic women with </span><span style="font-family:Verdana;">twin</span><span style="font-family:Verdana;"> pregnancy.展开更多
For complex orebodies in which the valuable metal is carried by several minerals that respond differently to the concentration process, an ore block model should not be characterized solely with elemental assays, as t...For complex orebodies in which the valuable metal is carried by several minerals that respond differently to the concentration process, an ore block model should not be characterized solely with elemental assays, as this information is not sufficient to anticipate the mill performances. Data from an iron ore concentrator is used to demonstrate the idea. A method is then proposed to estimate the mineral contents of ore samples from elemental assays. The method can readily be extended to combine the estimation of the mineral contents in the feed of the mill with an estimation of the recovery of these minerals into the products of the concentrator. These mineral recoveries can subsequently be incorporated into a block model to predict the concentrator response to the processing of an ore block.展开更多
基金The paper is supported by the key Science and Technology Project of Henan Province(0424290064) the fund items of Henan Province Natural Science( 0411050100).
文摘Effect of several complex inoculants on mechanical properties, process-ability and sensibility of grey cast iron used in cylinder block were investigated. The experimental results showed that the grey cast iron treated with 60%FeSi75+40%RE complex inoculants has tensile strength consistently at about 295 MPa along with good hardness and improved metallurgy quality. While the grey cast iron inoculated with 20%FeSi75+80%Sr compound inoculants has the best process-ability, the lowest cross-section sensibility and the least microhardness difference. The wear amount of the drill increases correspondingly with the increase of the microhardness difference of matrix structure, indicating the great effect of homogeneousness of matrix structure in the grey cast iron on the machinability of the grey cast iron.
文摘<b><span style="font-family:Verdana;">Introduction: </span></b><span style="font-family:Verdana;">It is estimated that about 18% of pregnant women suffer from iron deficiency anemia throughout their whole pregnancy.</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">In </span><span style="font-family:Verdana;">twin</span><span style="font-family:Verdana;"> pregnancy, owing to the relatively greater </span><span style="font-family:Verdana;">feto-placental</span><span style="font-family:Verdana;"> requirements and greater expansion in maternal plasma volume </span></span><span style="font-family:Verdana;">and red cell mass, iron requirements </span><span style="font-family:""><span style="font-family:Verdana;">are magnified 1.8 times compared to singleton pregnancies. However, for </span><span style="font-family:Verdana;">prevention</span><span style="font-family:Verdana;"> of iron deficiency in twin </span><span style="font-family:Verdana;">pregnancy</span><span style="font-family:Verdana;">, only sparse data exist regarding the sufficiency of the standard antenatal iron supplementation dose used in singleton pregnancies to meet the increased iron demand. In this study, we investigate the effect of single and double dose iron supplementation for </span><span style="font-family:Verdana;">prevention</span><span style="font-family:Verdana;"> of iron deficiency anemia in twin pregnancy. </span><b><span style="font-family:Verdana;">Methods: </span></b><span style="font-family:Verdana;">A randomized controlled clinical trial was conducted at our center in the period between February 2019 and October 2020,</span></span><span style="font-family:Verdana;"> and</span><span style="font-family:""> <span style="font-family:Verdana;">included</span><span style="font-family:Verdana;"> 450 eligible healthy non-anemic women aged 18 </span></span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;"> 35 years, with twin pregnancy at 12 </span><span style="font-family:Verdana;">-</span><span style="font-family:""><span style="font-family:Verdana;"> 16 weeks of gestation. After informed consent, eligible women were randomized to receive either single dose 27 mg, or double dose 54 mg elemental iron supplementation. Monitoring of hemoglobin concentration was done at fixed time points during gestation: at enrollment, 24 weeks, 32 weeks </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> before delivery. The primary outcome of the study was the incidence of iron deficiency anemia during </span><span style="font-family:Verdana;">follow up</span><span style="font-family:Verdana;"> until delivery. </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">The incidence of iron deficiency anemia in the two groups did not differ significantly between the </span><span style="font-family:Verdana;">single dose</span><span style="font-family:Verdana;"> group (19.1%) and the double dose group (24.0%). In women who did not develop Iron Deficiency Anemia, hemoglobin concentration varied significantly along the different gestational ages during the </span><span style="font-family:Verdana;">follow up</span><span style="font-family:Verdana;"> pe</span><span><span style="font-family:Verdana;">riod. In contrast, they did not show </span><span style="font-family:Verdana;">an overall statistically significant difference</span></span><span style="font-family:Verdana;"> in the hemoglobin concentrations between the single or double dose groups. </span><b><span style="font-family:Verdana;">Conclusion:</span></b> <span style="font-family:Verdana;">This</span><span style="font-family:Verdana;"> clinical trial did not demonstrate an added benefit for doubling prophylactic iron supplementation dose in non-anemic women with </span><span style="font-family:Verdana;">twin</span><span style="font-family:Verdana;"> pregnancy.
文摘For complex orebodies in which the valuable metal is carried by several minerals that respond differently to the concentration process, an ore block model should not be characterized solely with elemental assays, as this information is not sufficient to anticipate the mill performances. Data from an iron ore concentrator is used to demonstrate the idea. A method is then proposed to estimate the mineral contents of ore samples from elemental assays. The method can readily be extended to combine the estimation of the mineral contents in the feed of the mill with an estimation of the recovery of these minerals into the products of the concentrator. These mineral recoveries can subsequently be incorporated into a block model to predict the concentrator response to the processing of an ore block.