Herein, a multi-index analysis of the nickel content of an alloy, output rate of the alloy, nickel recovery rate, and iron recovery rate during the melting of laterite metallized pellets was performed. The thermodynam...Herein, a multi-index analysis of the nickel content of an alloy, output rate of the alloy, nickel recovery rate, and iron recovery rate during the melting of laterite metallized pellets was performed. The thermodynamic reduction behavior of oxides such as NiO, FeO, Fe_3 O_4, and Cr_2 O_3 was studied using the FactSage software, which revealed that SiO_2 is not conducive to the reduction of iron oxides, whereas the addition of basic oxides such as CaO and MgO is beneficial for the reduction of iron oxides. On the basis of a comprehensive analysis to achieve greater nickel recovery and lower iron recovery rates, the optimum experimental parameters in the orthogonal experiment were A3 B1 C3(t = 30 min, C/O = 0.4, R = 1.2); the indicators wNi, φalloy, ηNi, and ηFe had values of 15.0 wt%, 12.1%, 44.9%, and 96.4%, respectively. In single-factor experiments, increasing basicity(R) substantially improved the separation effect in the low-basicity range 0.5 ≤ R ≤ 0.8 but not in the high-basicity range 0.8 ≤ R ≤ 1.2. Similar results were obtained for the effect of the C/O ratio. Moreover, the recovery rate of nickel increased with increasing recovery rate of iron.展开更多
Long-term planning is one of the most important stages that determines the distribution of cash flows over the mine life and the feasibility of the project. However, it is not feasible in block caving to generate a pr...Long-term planning is one of the most important stages that determines the distribution of cash flows over the mine life and the feasibility of the project. However, it is not feasible in block caving to generate a production schedule that will provide optimal operating strategies without considering geotechnical constraints. This paper develops a mixed-integer linear programming(MILP) model to optimize the extraction sequence of drawpoints over multiple time horizons of block-cave mines with respect to the draw control systems. A multi-similarity index clustering technique to solve the MILP model in a reasonable time is also presented. Application and comparison of production scheduling based on the draw control system and clustering technique are illustrated using 325 drawpoints over 15 periods. The results show a significant reduction in the size of the MILP model, and in the time required to solve it.展开更多
A large volume of Remote Sensing(RS)data has been generated with the deployment of satellite technologies.The data facilitate research in ecological monitoring,land management and desertification,etc.The characteristi...A large volume of Remote Sensing(RS)data has been generated with the deployment of satellite technologies.The data facilitate research in ecological monitoring,land management and desertification,etc.The characteristics of RS data(e.g.,enormous volume,large single-file size,and demanding requirement of fault tolerance)make the Hadoop Distributed File System(HDFS)an ideal choice for RS data storage as it is efficient,scalable,and equipped with a data replication mechanism for failure resilience.To use RS data,one of the most important techniques is geospatial indexing.However,the large data volume makes it time-consuming to efficiently construct and leverage.Considering that most modern geospatial data centres are equipped with HDFS-based big data processing infrastructures,deploying multiple geospatial indices becomes natural to optimise the efficacy.Moreover,because of the reliability introduced by high-quality hardware and the infrequently modified property of the RS data,the use of multi-indexing will not cause large overhead.Therefore,we design a framework called Multi-IndeXing-RS(MIX-RS)that unifies the multi-indexing mechanism on top of the HDFS with data replication enabled for both fault tolerance and geospatial indexing efficiency.Given the fault tolerance provided by the HDFS,RS data are structurally stored inside for faster geospatial indexing.Additionally,multi-indexing enhances efficiency.The proposed technique naturally sits on top of the HDFS to form a holistic framework without incurring severe overhead or sophisticated system implementation efforts.The MIX-RS framework is implemented and evaluated using real remote sensing data provided by the Chinese Academy of Sciences,demonstrating excellent geospatial indexing performance.展开更多
With increasing diameters of aluminum alloy thin-walled tubes(AATTs),the tube forming limits,i.e.the minimum bending factors,and their predictions under multi-index constraints including wrinkling,thinning and flatten...With increasing diameters of aluminum alloy thin-walled tubes(AATTs),the tube forming limits,i.e.the minimum bending factors,and their predictions under multi-index constraints including wrinkling,thinning and flattening have been being a key problem to be urgently solved for improving tube forming potential in numerical control(NC)bending processes of AATTs with large diameters.Thus in this paper,a search algorithm of the forming limits is put forward based on a 3D elastic-plastic finite element(FE)model and a wrinkling energy prediction model for the bending processes under axial compression loading(ACL)or not.This algorithm enables to be considered the effects of process parameter combinations including die,friction parameters on the multi-indices.Based on this algorithm,the forming limits of the different size tubes are obtained,and the roles of the process parameter combinations in enabling the limit bending processes are also revealed.The followings are found:the first,within the appropriate ranges of friction and clearances between the different dies and the tubes enabling the bending processes with smaller bending factors,the ACL enables the tube limit bending processes after a decrease of the mandrel ball thickness and diameters;then,without considering the effects of the tube geometry sizes on the tube constitutive equations,the forming limits will be decided by the limit thinning values for the tubes with diameters smaller than 80 mm,while the wrinkling for the tubes with diameters no less than 80 mm.The forming limits obtained from this algorithm are smaller than the analytical results,and reduced by 57.39%;the last,the roles of the process parameter combinations in enabling the limit bending processes are verified by experimental results.展开更多
目的:采用多指标定量分析、化学模式识别结合优劣解距离法(technique for order preference by similarity to an ideal solution,TOPSIS)综合评价参榆洗剂质量。方法:采用高效液相色谱法同时测定15批参榆洗剂中苦参碱、氧化苦参碱、5-O...目的:采用多指标定量分析、化学模式识别结合优劣解距离法(technique for order preference by similarity to an ideal solution,TOPSIS)综合评价参榆洗剂质量。方法:采用高效液相色谱法同时测定15批参榆洗剂中苦参碱、氧化苦参碱、5-O-阿魏酰奎尼酸、盐酸黄柏碱、阿魏酸、槲皮苷、盐酸小檗碱、盐酸巴马汀的含量,借助聚类分析(hierarchical cluster analysis,HCA)、偏最小二乘判别分析(partial least squares discriminant analysis,PLS-DA)及TOPSIS模型,筛选影响质量的关键因子,并对质量优劣进行排序。结果:方法学考察结果均符合《中国药典》2020年版要求。HCA结果显示15批参榆洗剂可以聚为3类。PLS-DA筛选出变量重要性投影(variable importance in projection,VIP)值>1.0的3个成分,分别是盐酸巴马汀、槲皮苷、5-O-阿魏酰奎尼酸,可能是引起参榆洗剂质量差异的关键因子。TOPSIS分析结果显示最优解的欧氏贴近度在0.079~0.72之间。结论:该研究建立的方法简便快捷,可以用于对参榆洗剂的综合评价。展开更多
In this article, we propose a space-time Multi-Index Monte Carlo （MIMC） estimator for a one-dimensional parabolic stochastic partial differential equation （SPDE） of Zakai type. We compare the complexity with the M...In this article, we propose a space-time Multi-Index Monte Carlo （MIMC） estimator for a one-dimensional parabolic stochastic partial differential equation （SPDE） of Zakai type. We compare the complexity with the Multilevel Monte Carlo （MLMC） method of Giles and Reisinger （2012）, and find, by means of Fourier analysis, that the MIMC method： （i） has suboptimal complexity of 0（ε^-21 ｜ogε｜） for a root mean square error （RMSE） z if the same spatial discretisation as in the MLMC method is used; （ii） has a better complexity of 0（ε^-21 ｜ogε｜） if a carefully adapted discretisation is used; （iii） has to be adapted for non-smooth functionals. Numerical tests confirm these findings empirically.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 51474024, 51674021, and 51574021)
文摘Herein, a multi-index analysis of the nickel content of an alloy, output rate of the alloy, nickel recovery rate, and iron recovery rate during the melting of laterite metallized pellets was performed. The thermodynamic reduction behavior of oxides such as NiO, FeO, Fe_3 O_4, and Cr_2 O_3 was studied using the FactSage software, which revealed that SiO_2 is not conducive to the reduction of iron oxides, whereas the addition of basic oxides such as CaO and MgO is beneficial for the reduction of iron oxides. On the basis of a comprehensive analysis to achieve greater nickel recovery and lower iron recovery rates, the optimum experimental parameters in the orthogonal experiment were A3 B1 C3(t = 30 min, C/O = 0.4, R = 1.2); the indicators wNi, φalloy, ηNi, and ηFe had values of 15.0 wt%, 12.1%, 44.9%, and 96.4%, respectively. In single-factor experiments, increasing basicity(R) substantially improved the separation effect in the low-basicity range 0.5 ≤ R ≤ 0.8 but not in the high-basicity range 0.8 ≤ R ≤ 1.2. Similar results were obtained for the effect of the C/O ratio. Moreover, the recovery rate of nickel increased with increasing recovery rate of iron.
文摘Long-term planning is one of the most important stages that determines the distribution of cash flows over the mine life and the feasibility of the project. However, it is not feasible in block caving to generate a production schedule that will provide optimal operating strategies without considering geotechnical constraints. This paper develops a mixed-integer linear programming(MILP) model to optimize the extraction sequence of drawpoints over multiple time horizons of block-cave mines with respect to the draw control systems. A multi-similarity index clustering technique to solve the MILP model in a reasonable time is also presented. Application and comparison of production scheduling based on the draw control system and clustering technique are illustrated using 325 drawpoints over 15 periods. The results show a significant reduction in the size of the MILP model, and in the time required to solve it.
基金supported in part by Key-Area Research and Development Program of Guangdong Province(No.2020B010164002)the Fundamental Research Foundation of Shenzhen Technology and Innovation Council(No.KCXFZ20201221173613035).
文摘A large volume of Remote Sensing(RS)data has been generated with the deployment of satellite technologies.The data facilitate research in ecological monitoring,land management and desertification,etc.The characteristics of RS data(e.g.,enormous volume,large single-file size,and demanding requirement of fault tolerance)make the Hadoop Distributed File System(HDFS)an ideal choice for RS data storage as it is efficient,scalable,and equipped with a data replication mechanism for failure resilience.To use RS data,one of the most important techniques is geospatial indexing.However,the large data volume makes it time-consuming to efficiently construct and leverage.Considering that most modern geospatial data centres are equipped with HDFS-based big data processing infrastructures,deploying multiple geospatial indices becomes natural to optimise the efficacy.Moreover,because of the reliability introduced by high-quality hardware and the infrequently modified property of the RS data,the use of multi-indexing will not cause large overhead.Therefore,we design a framework called Multi-IndeXing-RS(MIX-RS)that unifies the multi-indexing mechanism on top of the HDFS with data replication enabled for both fault tolerance and geospatial indexing efficiency.Given the fault tolerance provided by the HDFS,RS data are structurally stored inside for faster geospatial indexing.Additionally,multi-indexing enhances efficiency.The proposed technique naturally sits on top of the HDFS to form a holistic framework without incurring severe overhead or sophisticated system implementation efforts.The MIX-RS framework is implemented and evaluated using real remote sensing data provided by the Chinese Academy of Sciences,demonstrating excellent geospatial indexing performance.
基金supported by the National Natural Science Foundation of China(Grant Nos.59975076,50175092,50905144)the National Science Found of China for Distinguished Young Scholars(Grant No.50225518)
文摘With increasing diameters of aluminum alloy thin-walled tubes(AATTs),the tube forming limits,i.e.the minimum bending factors,and their predictions under multi-index constraints including wrinkling,thinning and flattening have been being a key problem to be urgently solved for improving tube forming potential in numerical control(NC)bending processes of AATTs with large diameters.Thus in this paper,a search algorithm of the forming limits is put forward based on a 3D elastic-plastic finite element(FE)model and a wrinkling energy prediction model for the bending processes under axial compression loading(ACL)or not.This algorithm enables to be considered the effects of process parameter combinations including die,friction parameters on the multi-indices.Based on this algorithm,the forming limits of the different size tubes are obtained,and the roles of the process parameter combinations in enabling the limit bending processes are also revealed.The followings are found:the first,within the appropriate ranges of friction and clearances between the different dies and the tubes enabling the bending processes with smaller bending factors,the ACL enables the tube limit bending processes after a decrease of the mandrel ball thickness and diameters;then,without considering the effects of the tube geometry sizes on the tube constitutive equations,the forming limits will be decided by the limit thinning values for the tubes with diameters smaller than 80 mm,while the wrinkling for the tubes with diameters no less than 80 mm.The forming limits obtained from this algorithm are smaller than the analytical results,and reduced by 57.39%;the last,the roles of the process parameter combinations in enabling the limit bending processes are verified by experimental results.
文摘目的:采用多指标定量分析、化学模式识别结合优劣解距离法(technique for order preference by similarity to an ideal solution,TOPSIS)综合评价参榆洗剂质量。方法:采用高效液相色谱法同时测定15批参榆洗剂中苦参碱、氧化苦参碱、5-O-阿魏酰奎尼酸、盐酸黄柏碱、阿魏酸、槲皮苷、盐酸小檗碱、盐酸巴马汀的含量,借助聚类分析(hierarchical cluster analysis,HCA)、偏最小二乘判别分析(partial least squares discriminant analysis,PLS-DA)及TOPSIS模型,筛选影响质量的关键因子,并对质量优劣进行排序。结果:方法学考察结果均符合《中国药典》2020年版要求。HCA结果显示15批参榆洗剂可以聚为3类。PLS-DA筛选出变量重要性投影(variable importance in projection,VIP)值>1.0的3个成分,分别是盐酸巴马汀、槲皮苷、5-O-阿魏酰奎尼酸,可能是引起参榆洗剂质量差异的关键因子。TOPSIS分析结果显示最优解的欧氏贴近度在0.079~0.72之间。结论:该研究建立的方法简便快捷,可以用于对参榆洗剂的综合评价。
文摘In this article, we propose a space-time Multi-Index Monte Carlo （MIMC） estimator for a one-dimensional parabolic stochastic partial differential equation （SPDE） of Zakai type. We compare the complexity with the Multilevel Monte Carlo （MLMC） method of Giles and Reisinger （2012）, and find, by means of Fourier analysis, that the MIMC method： （i） has suboptimal complexity of 0（ε^-21 ｜ogε｜） for a root mean square error （RMSE） z if the same spatial discretisation as in the MLMC method is used; （ii） has a better complexity of 0（ε^-21 ｜ogε｜） if a carefully adapted discretisation is used; （iii） has to be adapted for non-smooth functionals. Numerical tests confirm these findings empirically.
