The grinding process in concentration plants of the metallurgical industry is of great importantce.. A mineral feed- ing SCADA system in the grinding process was designed with the idea of integrating management and co...The grinding process in concentration plants of the metallurgical industry is of great importantce.. A mineral feed- ing SCADA system in the grinding process was designed with the idea of integrating management and control functions. A detailed design and realization method of control and supervisory control levels in the system was introduced. At the control level, with an algorithm of a separate integrated PID, four mineral feeding machines are run in turn. The supervisory control level can generate process flow graphs, statistical report forms, historical trends and at the same time, it has the functions of alarm, system administration, user login, etc. After the mineral SCADA system has been started, the mineral feeding is very stable, the workstation completely supervises and controls the entire process of mineral feeding, and at the same time histori- cal data is shown and questions can be answered conveniently. The system runs well in the MeiShan Concentration Plant of the Shanghai Bao Shan Steel Group.展开更多
To improve the accuracy of fault location system, several short-circuit tests need to be conducted before being brought into service in autotransformer （AT） feeding systems for high-speed railways in China. However,...To improve the accuracy of fault location system, several short-circuit tests need to be conducted before being brought into service in autotransformer （AT） feeding systems for high-speed railways in China. However, no systematic algorithm yet exists to evaluate the consistency of the current distribution of short-circuit tests. A methodology is proposed in this paper to address this problem. Based on Kirchhoff’s current law and the generalized method of symmetrical components, the current deviations of the AT feeding systems are analysed and then normalized with the short-circuit current as they vary greatly with systems and short-circuit sites. It is also found that the short-circuit current varies with the calculation methods, and its unbiased standard deviation also reflects the consistency of the short-circuit test. The mean and maximum of the current deviations, as well as the unbiased standard deviation of the short-circuit current, show the consistency of the short-circuit test from different aspects,although the last two items are highly relevant. Therefore, a unified evaluation index is defined as the sum of the three items, and then applied in two case studies to test its performance. The results show that, the proposed index canclearly distinguish the consistency of the short-circuit tests and may be used to sort the short-circuit tests for fault location systems. Besides, some short-circuit tests may have very poor consistency indices, and thus are not applicable to the tuning of fault location systems. In the authors’ opinion, the determination of the threshold of the proposed index needs further investigation.展开更多
Parallel turbine-driven feedwater pumps are needed when ships travel at high speed. In order to study marine steam generator feedwater control systems which use parallel turbine-driven feed pumps, a mathematical model...Parallel turbine-driven feedwater pumps are needed when ships travel at high speed. In order to study marine steam generator feedwater control systems which use parallel turbine-driven feed pumps, a mathematical model of marine steam generator feedwater control system was developed which includes mathematical models of two steam generators and parallel turbine-driven feed pumps as well as mathematical models of feedwater pipes and feed regulating valves. The operating condition points of the parallel ttu-bine-driven feed pumps were calculated by the Chebyshev curve fit method. A water level controller for the steam generator and a rotary speed controller for the turbine-driven feed pumps were also included in the model. The accuracy of the mathematical models and their controllers was verified by comparing their results with those from a simulator.展开更多
The medium -large caliber naval gun is still playing an important role in modern war. The development of highly automatic Shell Raising and Feeding System (SRFS) in the world has been briefly outlined. Several typical...The medium -large caliber naval gun is still playing an important role in modern war. The development of highly automatic Shell Raising and Feeding System (SRFS) in the world has been briefly outlined. Several typical SRFS of medium-large caliber naval guns have been analyzed. A re-design of the system is introduced, in which systematic design method has been used to demonstrate its feasibility. The design goal of the system is to realize rapid shell feeding, with application to many types of shells, quick change of shell types , accurate and reliable feeding operation, simple mechanical structure and easy realization of shell withdrawing.展开更多
Ethoxyquin(EQ)is a widely used feed additives for aquaculture,but the potential hazard to fish and consumers are not fully understood.In this work,EQ was applied to tilapia fed with either high-fat or low-fat feed,and...Ethoxyquin(EQ)is a widely used feed additives for aquaculture,but the potential hazard to fish and consumers are not fully understood.In this work,EQ was applied to tilapia fed with either high-fat or low-fat feed,and the changes in growth performance and intestinal barrier integrality of genetically improved farmed tilapia was observed.Additionally,the microbiota in the intestinal content and flesh was analyzed by 16S rDNA sequencing,and the flesh metabolites was measured by LC-MS/MS untargeted metabolomics.In the low-fat group,EQ increased weight gain and feed conversion rate,but reduced survival rate.In the high-fat group,only weight gain decreased,and there was no significant effect on feed conversion rate and survival rate.Additionally,the intestinal villi and microbiota diversity was impaired in both feeding conditions.Microbiota analysis revealed that EQ resulted in different composition and lower diversity of the flesh microbiota and upregulated the proportion of potential pathogens.EQ also changed the flesh metabolome,decreasing beneficial metabolites and increasing potential harmful components.This work elucidated the effect of EQ on growth performance of tilapia and implied that it has adverse effects on tilapia and may be passed on to consumers.展开更多
前端工程设计(Front End Engineering Design,FEED)在工程设计中起着至关重要的作用。笔者介绍了集成化软件Comos FEED的特点,并对其在石油化工工艺设计过程中的应用进行了深入探讨。该软件的应用改变了传统的设计信息独立分散的设计模...前端工程设计(Front End Engineering Design,FEED)在工程设计中起着至关重要的作用。笔者介绍了集成化软件Comos FEED的特点,并对其在石油化工工艺设计过程中的应用进行了深入探讨。该软件的应用改变了传统的设计信息独立分散的设计模式,在充分保证数据的准确性和一致性的基础上,将工艺设计人员从繁琐的数据录入与核对中解放出来,大幅度提高工程设计效率和质量。明确应用需求、有针对性的二次开发、规范现有工作流是该软件在实际工程项目应用的关键。展开更多
介绍了设立FEED(front-end engineering and design)阶段的背景,分析了石油化工项目早期投资决策所面临的挑战,探讨了早期FEED的最佳实践,明确了FEED最佳实践的目标是采用共享的中心工艺流程数据库,并采用并行的工作流程,多专业协同开...介绍了设立FEED(front-end engineering and design)阶段的背景,分析了石油化工项目早期投资决策所面临的挑战,探讨了早期FEED的最佳实践,明确了FEED最佳实践的目标是采用共享的中心工艺流程数据库,并采用并行的工作流程,多专业协同开展工作;同时采用管道快速自动敷设的三维工厂设计模型软件,依据初步的工艺设计,快速建立工程的三维模型,并作为提取大宗材料工程量的主要依据之一。为石油化工项目建立早决策、快决策以及科学决策的工作流程提供了良好的借鉴。展开更多
To solve the problem of water seepage of vertical feeding borehole for solid materials,we established the fluid-solid coupling dynamic model of groundwater flowing in rock mass adjacent to the vertical feeding borehol...To solve the problem of water seepage of vertical feeding borehole for solid materials,we established the fluid-solid coupling dynamic model of groundwater flowing in rock mass adjacent to the vertical feeding borehole.Combining with the engineering geological conditions,we built a numeral model to study the influence rule of the aquifer hydraulic pressure and seepage location of feeding borehole on the amount of seepage with fnite element numerical method.The results show that the nonlinear relationship is presented among the amount of seepage,the seepage location and aquifer hydraulic pressure.The higher the aquifer hydraulic pressure is,the closer the distance between seepage location and aquifer is,and the faster the harmful levels of aquifer will grow.In practice,we calculated the allowable seepage of feeding borehole by the optimum moisture content and natural moisture content of backflling materials,and then determined the protection zone of feeding borehole,so the moisture content of backflling materials can be controlled within the scope of optimum moisture content.展开更多
Hainan eldi’s deer is a precious species of deer in the tropic zone,it is regardedas the first—class animal under protection in China.Based on all-year-round observation on thedeer’s feeding habit in the reserve fr...Hainan eldi’s deer is a precious species of deer in the tropic zone,it is regardedas the first—class animal under protection in China.Based on all-year-round observation on thedeer’s feeding habit in the reserve from 1985 to 1988,we discovered that Hainan eldi’s deer is aeuryphangous herbivore.They take various herbs as their main food and have fairly strongselectivity for woody plants,especially tending to eat the tender parts of plants and some fruits andflowers.Like other species of deer,they also like to lick the alkaline soil.This paper reports the re-search and evaluation on the feeding and choosing food characteristics of Hainan eldi’s deer,and onthe palatability of the main plants in the reserve.展开更多
Fluorescent silk is fundamentally important for the development of future tissue engineering scaffolds.Despite great progress in the preparation of a variety of colored silks,fluorescent silk with enhanced mechanical ...Fluorescent silk is fundamentally important for the development of future tissue engineering scaffolds.Despite great progress in the preparation of a variety of colored silks,fluorescent silk with enhanced mechanical properties has yet to be explored.In this study,we report on the fabrication of intrinsically super-strong fluorescent silk by feeding Bombyx mori silkworm carbon nanodots(CNDs).The CNDs were incorporated into silk fibroin,hindering the conformation transformation,confining crystallization,and inducing orientation of mesophase.The resultant silk exhibited super-strong mechanical properties with breaking strength of 521.9±82.7 MPa and breaking elongation of 19.2±4.3%,improvements of 55.1%and 53.6%,respectively,in comparison with regular silk.The CNDs-reinforced silk displayed intrinsic blue fluorescence when exposed to 405 nm laser and exhibited no cytotoxic effect on cells,suggesting that multi-functional silks would be potentially useful in bioimaging and other applications.展开更多
Misreported pyrite into copper concentrates dramatically declines copper grade and recovery. Copper flotation can be also more complicated if flotation feed comes from an elevated-pyritic copper ore. In this investiga...Misreported pyrite into copper concentrates dramatically declines copper grade and recovery. Copper flotation can be also more complicated if flotation feed comes from an elevated-pyritic copper ore. In this investigation, the effect of two different ore types(high pyritic and low pyritic feeds) was studied on rougher stage of industrial copper flotation circuit. Samples were taken from different streams and the structure of chalcopyrite within the pyrite and non-sulfide gangue minerals was examined in various size fractions for mentioned ore types. Results indicated that 72% and 56% of the total floated pyrite was transferred to concentrate in first four cells in the low and high pyritic feeds, respectively. Whereas, this proportion for floated SiO_2 in last ten cells was detected as 72% and 71%, respectively. A detailed interpretation of the effect of locked particles in different size fractions on rougher flotation cells is studied from industrial point of view.展开更多
文摘The grinding process in concentration plants of the metallurgical industry is of great importantce.. A mineral feed- ing SCADA system in the grinding process was designed with the idea of integrating management and control functions. A detailed design and realization method of control and supervisory control levels in the system was introduced. At the control level, with an algorithm of a separate integrated PID, four mineral feeding machines are run in turn. The supervisory control level can generate process flow graphs, statistical report forms, historical trends and at the same time, it has the functions of alarm, system administration, user login, etc. After the mineral SCADA system has been started, the mineral feeding is very stable, the workstation completely supervises and controls the entire process of mineral feeding, and at the same time histori- cal data is shown and questions can be answered conveniently. The system runs well in the MeiShan Concentration Plant of the Shanghai Bao Shan Steel Group.
文摘To improve the accuracy of fault location system, several short-circuit tests need to be conducted before being brought into service in autotransformer （AT） feeding systems for high-speed railways in China. However, no systematic algorithm yet exists to evaluate the consistency of the current distribution of short-circuit tests. A methodology is proposed in this paper to address this problem. Based on Kirchhoff’s current law and the generalized method of symmetrical components, the current deviations of the AT feeding systems are analysed and then normalized with the short-circuit current as they vary greatly with systems and short-circuit sites. It is also found that the short-circuit current varies with the calculation methods, and its unbiased standard deviation also reflects the consistency of the short-circuit test. The mean and maximum of the current deviations, as well as the unbiased standard deviation of the short-circuit current, show the consistency of the short-circuit test from different aspects,although the last two items are highly relevant. Therefore, a unified evaluation index is defined as the sum of the three items, and then applied in two case studies to test its performance. The results show that, the proposed index canclearly distinguish the consistency of the short-circuit tests and may be used to sort the short-circuit tests for fault location systems. Besides, some short-circuit tests may have very poor consistency indices, and thus are not applicable to the tuning of fault location systems. In the authors’ opinion, the determination of the threshold of the proposed index needs further investigation.
文摘Parallel turbine-driven feedwater pumps are needed when ships travel at high speed. In order to study marine steam generator feedwater control systems which use parallel turbine-driven feed pumps, a mathematical model of marine steam generator feedwater control system was developed which includes mathematical models of two steam generators and parallel turbine-driven feed pumps as well as mathematical models of feedwater pipes and feed regulating valves. The operating condition points of the parallel ttu-bine-driven feed pumps were calculated by the Chebyshev curve fit method. A water level controller for the steam generator and a rotary speed controller for the turbine-driven feed pumps were also included in the model. The accuracy of the mathematical models and their controllers was verified by comparing their results with those from a simulator.
文摘The medium -large caliber naval gun is still playing an important role in modern war. The development of highly automatic Shell Raising and Feeding System (SRFS) in the world has been briefly outlined. Several typical SRFS of medium-large caliber naval guns have been analyzed. A re-design of the system is introduced, in which systematic design method has been used to demonstrate its feasibility. The design goal of the system is to realize rapid shell feeding, with application to many types of shells, quick change of shell types , accurate and reliable feeding operation, simple mechanical structure and easy realization of shell withdrawing.
基金supported by the National Natural Science Foundation of China(32061133004)the Major Project of Digital Plus Discipline Construction of Zhejiang Gongshang University(SZJ2022A010)the Zhejiang Provincial Natural Science Foundation of China(LGN21C200013).
文摘Ethoxyquin(EQ)is a widely used feed additives for aquaculture,but the potential hazard to fish and consumers are not fully understood.In this work,EQ was applied to tilapia fed with either high-fat or low-fat feed,and the changes in growth performance and intestinal barrier integrality of genetically improved farmed tilapia was observed.Additionally,the microbiota in the intestinal content and flesh was analyzed by 16S rDNA sequencing,and the flesh metabolites was measured by LC-MS/MS untargeted metabolomics.In the low-fat group,EQ increased weight gain and feed conversion rate,but reduced survival rate.In the high-fat group,only weight gain decreased,and there was no significant effect on feed conversion rate and survival rate.Additionally,the intestinal villi and microbiota diversity was impaired in both feeding conditions.Microbiota analysis revealed that EQ resulted in different composition and lower diversity of the flesh microbiota and upregulated the proportion of potential pathogens.EQ also changed the flesh metabolome,decreasing beneficial metabolites and increasing potential harmful components.This work elucidated the effect of EQ on growth performance of tilapia and implied that it has adverse effects on tilapia and may be passed on to consumers.
文摘前端工程设计(Front End Engineering Design,FEED)在工程设计中起着至关重要的作用。笔者介绍了集成化软件Comos FEED的特点,并对其在石油化工工艺设计过程中的应用进行了深入探讨。该软件的应用改变了传统的设计信息独立分散的设计模式,在充分保证数据的准确性和一致性的基础上,将工艺设计人员从繁琐的数据录入与核对中解放出来,大幅度提高工程设计效率和质量。明确应用需求、有针对性的二次开发、规范现有工作流是该软件在实际工程项目应用的关键。
文摘介绍了设立FEED(front-end engineering and design)阶段的背景,分析了石油化工项目早期投资决策所面临的挑战,探讨了早期FEED的最佳实践,明确了FEED最佳实践的目标是采用共享的中心工艺流程数据库,并采用并行的工作流程,多专业协同开展工作;同时采用管道快速自动敷设的三维工厂设计模型软件,依据初步的工艺设计,快速建立工程的三维模型,并作为提取大宗材料工程量的主要依据之一。为石油化工项目建立早决策、快决策以及科学决策的工作流程提供了良好的借鉴。
基金funded by the State Key Development Program for Basic Research of China(No.2013CB227900)the National High Technology Joint Research Program of China(No.2012BAB13B00)
文摘To solve the problem of water seepage of vertical feeding borehole for solid materials,we established the fluid-solid coupling dynamic model of groundwater flowing in rock mass adjacent to the vertical feeding borehole.Combining with the engineering geological conditions,we built a numeral model to study the influence rule of the aquifer hydraulic pressure and seepage location of feeding borehole on the amount of seepage with fnite element numerical method.The results show that the nonlinear relationship is presented among the amount of seepage,the seepage location and aquifer hydraulic pressure.The higher the aquifer hydraulic pressure is,the closer the distance between seepage location and aquifer is,and the faster the harmful levels of aquifer will grow.In practice,we calculated the allowable seepage of feeding borehole by the optimum moisture content and natural moisture content of backflling materials,and then determined the protection zone of feeding borehole,so the moisture content of backflling materials can be controlled within the scope of optimum moisture content.
文摘Hainan eldi’s deer is a precious species of deer in the tropic zone,it is regardedas the first—class animal under protection in China.Based on all-year-round observation on thedeer’s feeding habit in the reserve from 1985 to 1988,we discovered that Hainan eldi’s deer is aeuryphangous herbivore.They take various herbs as their main food and have fairly strongselectivity for woody plants,especially tending to eat the tender parts of plants and some fruits andflowers.Like other species of deer,they also like to lick the alkaline soil.This paper reports the re-search and evaluation on the feeding and choosing food characteristics of Hainan eldi’s deer,and onthe palatability of the main plants in the reserve.
基金sponsored by the National Key Research and Development Program of China(2016YFA0201700,2016YFA0201702)the Fundamental Research Funds for the Central Universities(2232019A3-06,2232019D3-02)+2 种基金the National Key Research and Development Program of China(2018YFC1105800)the National Natural Science Foundation of China(21674018,51903045)the Shanghai Belt and Road Joint Laboratory of Advanced Fiber and Low-Dimension Materials(18520750400).
文摘Fluorescent silk is fundamentally important for the development of future tissue engineering scaffolds.Despite great progress in the preparation of a variety of colored silks,fluorescent silk with enhanced mechanical properties has yet to be explored.In this study,we report on the fabrication of intrinsically super-strong fluorescent silk by feeding Bombyx mori silkworm carbon nanodots(CNDs).The CNDs were incorporated into silk fibroin,hindering the conformation transformation,confining crystallization,and inducing orientation of mesophase.The resultant silk exhibited super-strong mechanical properties with breaking strength of 521.9±82.7 MPa and breaking elongation of 19.2±4.3%,improvements of 55.1%and 53.6%,respectively,in comparison with regular silk.The CNDs-reinforced silk displayed intrinsic blue fluorescence when exposed to 405 nm laser and exhibited no cytotoxic effect on cells,suggesting that multi-functional silks would be potentially useful in bioimaging and other applications.
基金the financial support of National Iranian Copper Industries Company (N.I.C.I.Co.)
文摘Misreported pyrite into copper concentrates dramatically declines copper grade and recovery. Copper flotation can be also more complicated if flotation feed comes from an elevated-pyritic copper ore. In this investigation, the effect of two different ore types(high pyritic and low pyritic feeds) was studied on rougher stage of industrial copper flotation circuit. Samples were taken from different streams and the structure of chalcopyrite within the pyrite and non-sulfide gangue minerals was examined in various size fractions for mentioned ore types. Results indicated that 72% and 56% of the total floated pyrite was transferred to concentrate in first four cells in the low and high pyritic feeds, respectively. Whereas, this proportion for floated SiO_2 in last ten cells was detected as 72% and 71%, respectively. A detailed interpretation of the effect of locked particles in different size fractions on rougher flotation cells is studied from industrial point of view.
