In order to deeply understand the grain growth behaviors of Ni80A superalloy,a series of grain growth experiments were conducted at holding temperatures ranging from 1223 to 1423 K and holding time ranging from 0 to 3...In order to deeply understand the grain growth behaviors of Ni80A superalloy,a series of grain growth experiments were conducted at holding temperatures ranging from 1223 to 1423 K and holding time ranging from 0 to 3600 s.A back-propagation artificial neural network(BP-ANN)model and a Sellars model were solved based on the experimental data.The prediction and generalization capabilities of these two models were evaluated and compared on the basis of four statistical indicators.The results show that the solved BP-ANN model has better performance as it has higher correlation coefficient(r),lower average absolute relative error(AARE),lower absolute values of mean value(μ)and standard deviation(ω).Eventually,a response surface of average grain size to holding temperature and holding time is constructed based on the data expanded by the solved BP-ANN model,and the grain growth behaviors are described.展开更多
This study presents the design of a modified attributed control chart based on a double sampling(DS)np chart applied in combination with generalized multiple dependent state(GMDS)sampling to monitor the mean life of t...This study presents the design of a modified attributed control chart based on a double sampling(DS)np chart applied in combination with generalized multiple dependent state(GMDS)sampling to monitor the mean life of the product based on the time truncated life test employing theWeibull distribution.The control chart developed supports the examination of the mean lifespan variation for a particular product in the process of manufacturing.Three control limit levels are used:the warning control limit,inner control limit,and outer control limit.Together,they enhance the capability for variation detection.A genetic algorithm can be used for optimization during the in-control process,whereby the optimal parameters can be established for the proposed control chart.The control chart performance is assessed using the average run length,while the influence of the model parameters upon the control chart solution is assessed via sensitivity analysis based on an orthogonal experimental design withmultiple linear regression.A comparative study was conducted based on the out-of-control average run length,in which the developed control chart offered greater sensitivity in the detection of process shifts while making use of smaller samples on average than is the case for existing control charts.Finally,to exhibit the utility of the developed control chart,this paper presents its application using simulated data with parameters drawn from the real set of data.展开更多
Mangrove reforestation with introduced species has been an important strategy to restore mangrove ecosystem functioning.However,how such activities affect microbially driven methane(CH4),nitrogen(N),and sulfur(S)cycli...Mangrove reforestation with introduced species has been an important strategy to restore mangrove ecosystem functioning.However,how such activities affect microbially driven methane(CH4),nitrogen(N),and sulfur(S)cycling of rhizosphere microbiomes remains unclear.To understand the effect of environmental selection and the evolutionary process on microbially driven biogeochemical cycles in native and introduced mangrove rhizospheres,we analyzed key genomic and functional profiles of rhizosphere microbiomes from native and introduced mangrove species by metagenome sequencing technologies.Compared with the native mangrove(Kandelia obovata,KO),the introduced mangrove(Sonneratia apetala,SA)rhizosphere microbiome had significantly(p<0.05)higher average genome size(AGS)(5.8 vs.5.5 Mb),average 16S ribosomal RNA gene copy number(3.5 vs.3.1),relative abundances of mobile genetic elements,and functional diversity in terms of the Shannon index(7.88 vs.7.84)but lower functional potentials involved in CH4 cycling(e.g.,mcrABCDG and pmoABC),N2 fixation(nifHDK),and inorganic S cycling(dsrAB,dsrC,dsrMKJOP,soxB,sqr,and fccAB).Similar results were also observed from the recovered Proteobacterial metagenome-assembled genomes with a higher AGS and distinct functions in the introduced mangrove rhizosphere.Additionally,salinity and ammonium were identified as the main environmental drivers of functional profiles of mangrove rhizosphere microbiomes through deterministic processes.This study advances our understanding of microbially mediated biogeochemical cycling of CH_(4),N,and S in the mangrove rhizosphere and provides novel insights into the influence of environmental selection and evolutionary processes on ecosystem functions,which has important implications for future mangrove reforestation.展开更多
The velocity distribution of sinter and gas in vertical cooling furnace(VCF)has an important influence on gas-solid heat transfer.Based on the slot model of single hopper in the VCF of Meishan Iron and Steel Co.,Ltd.,...The velocity distribution of sinter and gas in vertical cooling furnace(VCF)has an important influence on gas-solid heat transfer.Based on the slot model of single hopper in the VCF of Meishan Iron and Steel Co.,Ltd.,the velocity and particle size distribution of sinter and the velocity and pressure distribution of gas were studied using a computational fluid dynamics-discrete element method model to obtain the gas-solid flow rule in the VCF.The results showed that the velocity of sinter near the wall and the edge of vent cowl was lower than that in the rest of the same plane.Therefore,the rectangular section of the vertical cooling furnace can be divided into a quasi-static zone,a plug flow zone and a convergent flow zone according to the flow velocity of the sinter.The average particle size and the void fraction of sinter bed were distributed in"W"and"V"shape along the width direction,respectively.The distribution of gas velocity in the furnace cavity was uneven,and the high-velocity area gradually changed from the center to the edge of the furnace cavity with the rise of gas.Reducing the ratio of edge to center gas flow from 2.7∶1 to 0.7∶1 could improve the gas velocity,but could not change the gas velocity distribution.The gas velocity distribution was more affected by the average particle size distribution of the sinter bed.It was suggested that measures need be taken to adjust it to improve the gas velocity distribution in the VCF.展开更多
In order to deal with the disadvantages of excessive grinding and non-uniformity in finished particle under high-pressure grinding rolls （HPGR） finished grinding system, four aspects were investigated, including eva...In order to deal with the disadvantages of excessive grinding and non-uniformity in finished particle under high-pressure grinding rolls （HPGR） finished grinding system, four aspects were investigated, including evaluating indicators, effects of operating factors, effect of particle uniformity on the flotation and formation mechanism of particle uniformity. Experiment of HPGR finished grinding system, cationic reverse flotation experiment and simulation test of particle bed comminution under the condition of quasi-static were carried out. Theoretical analyses indicated that both of uniformity coefficient and average particle size should be included in the uniformity analysis of the mineral particles. The results show that the effect of circulation fan impeller speed on particle uniformity is the most evident, HPGR working pressure and roll gap are second and HPGR roller speed is the last. Average particle size has a more obvious effect on the grade of flotation concentrate while uniformity coefficient has a more obvious effect on the flotation recovery. Considering the two aspects of grade and recovery, the optimal uniformity coefficient for flotation is 1.1-1.2 and the optimal average particle size for flotation is 50-55 μm. The operating factors which promote the shielding effect and compact effect in the HPGR finished grinding system should be strengthened based on the uniformity of particles.展开更多
基金Project(cstc2018jcyjAX0459)supported by Chongqing Basic Research and Frontier Exploration Program,ChinaProjects(2019CDQYTM027,2019CDJGFCL003)supported by the Fundamental Research Funds for the Central Universities,China。
文摘In order to deeply understand the grain growth behaviors of Ni80A superalloy,a series of grain growth experiments were conducted at holding temperatures ranging from 1223 to 1423 K and holding time ranging from 0 to 3600 s.A back-propagation artificial neural network(BP-ANN)model and a Sellars model were solved based on the experimental data.The prediction and generalization capabilities of these two models were evaluated and compared on the basis of four statistical indicators.The results show that the solved BP-ANN model has better performance as it has higher correlation coefficient(r),lower average absolute relative error(AARE),lower absolute values of mean value(μ)and standard deviation(ω).Eventually,a response surface of average grain size to holding temperature and holding time is constructed based on the data expanded by the solved BP-ANN model,and the grain growth behaviors are described.
基金the Science,Research and Innovation Promotion Funding(TSRI)(Grant No.FRB660012/0168)managed under Rajamangala University of Technology Thanyaburi(FRB66E0646O.4).
文摘This study presents the design of a modified attributed control chart based on a double sampling(DS)np chart applied in combination with generalized multiple dependent state(GMDS)sampling to monitor the mean life of the product based on the time truncated life test employing theWeibull distribution.The control chart developed supports the examination of the mean lifespan variation for a particular product in the process of manufacturing.Three control limit levels are used:the warning control limit,inner control limit,and outer control limit.Together,they enhance the capability for variation detection.A genetic algorithm can be used for optimization during the in-control process,whereby the optimal parameters can be established for the proposed control chart.The control chart performance is assessed using the average run length,while the influence of the model parameters upon the control chart solution is assessed via sensitivity analysis based on an orthogonal experimental design withmultiple linear regression.A comparative study was conducted based on the out-of-control average run length,in which the developed control chart offered greater sensitivity in the detection of process shifts while making use of smaller samples on average than is the case for existing control charts.Finally,to exhibit the utility of the developed control chart,this paper presents its application using simulated data with parameters drawn from the real set of data.
基金supported by the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(SML2020SP004)the National Natural Science Foundation of China(91951207,32100077,31770539,31870469,42177011,41676105,41771095,62170346)the China Postdoctoral Science Foundation(2021M703751).
文摘Mangrove reforestation with introduced species has been an important strategy to restore mangrove ecosystem functioning.However,how such activities affect microbially driven methane(CH4),nitrogen(N),and sulfur(S)cycling of rhizosphere microbiomes remains unclear.To understand the effect of environmental selection and the evolutionary process on microbially driven biogeochemical cycles in native and introduced mangrove rhizospheres,we analyzed key genomic and functional profiles of rhizosphere microbiomes from native and introduced mangrove species by metagenome sequencing technologies.Compared with the native mangrove(Kandelia obovata,KO),the introduced mangrove(Sonneratia apetala,SA)rhizosphere microbiome had significantly(p<0.05)higher average genome size(AGS)(5.8 vs.5.5 Mb),average 16S ribosomal RNA gene copy number(3.5 vs.3.1),relative abundances of mobile genetic elements,and functional diversity in terms of the Shannon index(7.88 vs.7.84)but lower functional potentials involved in CH4 cycling(e.g.,mcrABCDG and pmoABC),N2 fixation(nifHDK),and inorganic S cycling(dsrAB,dsrC,dsrMKJOP,soxB,sqr,and fccAB).Similar results were also observed from the recovered Proteobacterial metagenome-assembled genomes with a higher AGS and distinct functions in the introduced mangrove rhizosphere.Additionally,salinity and ammonium were identified as the main environmental drivers of functional profiles of mangrove rhizosphere microbiomes through deterministic processes.This study advances our understanding of microbially mediated biogeochemical cycling of CH_(4),N,and S in the mangrove rhizosphere and provides novel insights into the influence of environmental selection and evolutionary processes on ecosystem functions,which has important implications for future mangrove reforestation.
基金Financial support provided by the Fundamental Research Funds for the Central Universities of China(N2225022)is gratefully acknowledged.
文摘The velocity distribution of sinter and gas in vertical cooling furnace(VCF)has an important influence on gas-solid heat transfer.Based on the slot model of single hopper in the VCF of Meishan Iron and Steel Co.,Ltd.,the velocity and particle size distribution of sinter and the velocity and pressure distribution of gas were studied using a computational fluid dynamics-discrete element method model to obtain the gas-solid flow rule in the VCF.The results showed that the velocity of sinter near the wall and the edge of vent cowl was lower than that in the rest of the same plane.Therefore,the rectangular section of the vertical cooling furnace can be divided into a quasi-static zone,a plug flow zone and a convergent flow zone according to the flow velocity of the sinter.The average particle size and the void fraction of sinter bed were distributed in"W"and"V"shape along the width direction,respectively.The distribution of gas velocity in the furnace cavity was uneven,and the high-velocity area gradually changed from the center to the edge of the furnace cavity with the rise of gas.Reducing the ratio of edge to center gas flow from 2.7∶1 to 0.7∶1 could improve the gas velocity,but could not change the gas velocity distribution.The gas velocity distribution was more affected by the average particle size distribution of the sinter bed.It was suggested that measures need be taken to adjust it to improve the gas velocity distribution in the VCF.
基金Project(2013EG132088)supported by Special Program for Research Institutes of the Ministry of Science and Technology,ChinaProject(12010402c187)supported by Key Science and Technology Program of Anhui Province,China
文摘In order to deal with the disadvantages of excessive grinding and non-uniformity in finished particle under high-pressure grinding rolls （HPGR） finished grinding system, four aspects were investigated, including evaluating indicators, effects of operating factors, effect of particle uniformity on the flotation and formation mechanism of particle uniformity. Experiment of HPGR finished grinding system, cationic reverse flotation experiment and simulation test of particle bed comminution under the condition of quasi-static were carried out. Theoretical analyses indicated that both of uniformity coefficient and average particle size should be included in the uniformity analysis of the mineral particles. The results show that the effect of circulation fan impeller speed on particle uniformity is the most evident, HPGR working pressure and roll gap are second and HPGR roller speed is the last. Average particle size has a more obvious effect on the grade of flotation concentrate while uniformity coefficient has a more obvious effect on the flotation recovery. Considering the two aspects of grade and recovery, the optimal uniformity coefficient for flotation is 1.1-1.2 and the optimal average particle size for flotation is 50-55 μm. The operating factors which promote the shielding effect and compact effect in the HPGR finished grinding system should be strengthened based on the uniformity of particles.
