A numerical model of foundry filling process was established based on the smoothed particle hydrodynamics（SPH）method.To mimic the constraints that the solid mold prescribes on the filling fluid,a composite treatment...A numerical model of foundry filling process was established based on the smoothed particle hydrodynamics（SPH）method.To mimic the constraints that the solid mold prescribes on the filling fluid,a composite treatment to the solid boundaries is elaborately designed.On solid boundary surfaces,boundary particles were set,which exert Lennard-Jones force on approaching fluid particles;inside the solid mold,ghost particles were arranged to complete the compact domain of near-boundary fluid particles.Water analog experiments were conducted in parallel with the model simulations.Very good agreement between experimental and simulation results demonstrates the success of model development.展开更多
In Burkina Faso, one of the three largest gold producers in West Africa, foundry activity is often paralyzed when basic equipment such as crucibles and cups are not available or should be imported. However, previous s...In Burkina Faso, one of the three largest gold producers in West Africa, foundry activity is often paralyzed when basic equipment such as crucibles and cups are not available or should be imported. However, previous studies have shown the availability of kaolinite-rich clay resources that could be used for the local manufacture of silico-aluminous ceramic crucibles. This work allowed to manufacture industrial ceramic crucibles with local clays and then they were tested in foundry industry. The materials were manufactured from three (03) raw materials including two clays (SAB and ROU) and sand. The chemical and mineral analysis has shown that the raw materials are suitable for the formulation of refractory materials. The results of characterization of the materials formulated showed that the properties of use are appreciable. The porosity of the materials is relatively low (23 - 28 vol%) with a diametral compressive strength between 0.61 and 1.34 MPa. Crucibles sintered at 1250˚C with a stay of 2 hours have a mechanical strength capable of supporting the weight of the ores contained. These crucibles have a refractoriness under load (T0.5) above 1141˚C and resist chemical attacks. Tests were carried out in the industry at 1100˚C, and the results were satisfactory.展开更多
本文介绍了VMware近期新推出的一个开源PaaS项目:Cloud Foundry。PaaS是Platform as a Service的缩写,意思是平台即服务。PaaS将软件部署,运行和维护整合成一种服务,以SaaS(Software as a Service软件即服务)的模式提交给开发人员。开...本文介绍了VMware近期新推出的一个开源PaaS项目:Cloud Foundry。PaaS是Platform as a Service的缩写,意思是平台即服务。PaaS将软件部署,运行和维护整合成一种服务,以SaaS(Software as a Service软件即服务)的模式提交给开发人员。开发人员可以快速地在其上进行软件开发部署,运行和扩展,而不用去搭建和维护硬件设施,安装软件中间件。将开发人员从软件部署,运行和维护软件的工作中解脱出来。本文指出了现代软件系统的新特点及遇到的挑战,介绍了PaaS的概念、Cloud Foundry的架构,分析了Cloud Foundry与业界现有几款PaaS相比的优点。最后,对PaaS未来的发展方向做了展望。展开更多
PPDB issues-four aspects of current management issues of foundry enterprises are discussed in this paper,including Production Management,Process Control,Duration Monitoring and Business Intelligence Data Analysis.Also...PPDB issues-four aspects of current management issues of foundry enterprises are discussed in this paper,including Production Management,Process Control,Duration Monitoring and Business Intelligence Data Analysis.Also a whole Enterprise Resource Planning(ERP) solution for foundry enterprises is proposed.The solution contains many models,four of which are used to solve the PPDB issues.These are called SPDB models,which separately are the Single-piece management model(based on casting lifecycle),Process management model(based on task-driven technology),Duration monitoring model(based on surplus period),and Business intelligence data analysis model(based on data mining).An ERP system for foundry enterprises,named HZERP,was researched and developed,and applied to a sand casting company of single piece and small batch production.Qualitatively and quantitatively comparing the application effect before and after implementing the HZERP system,the result demonstrated that the foundry ERP system based on the SPDB models can help metal casting enterprises achieve the single-piece management,better regulate the production processes,improve production and delivery management,shorten the production cycle,reduce costs,and speed up the capital turnover to a large extent.展开更多
Objectives The purposes were to determine the relationship between silicosis among foundry workers and their cumulative exposure to silica dust, and to establish a regression model to predict the risk for developing s...Objectives The purposes were to determine the relationship between silicosis among foundry workers and their cumulative exposure to silica dust, and to establish a regression model to predict the risk for developing silicosis by a given length of employment and air concentrations of silica at worksites. Methods A 29-year cohort study was conducted, including all those employed for more than one year during January 1, 1980 to December 31, 1996 and all members of the cohort were followed-up to December 3 1, 2008. In total, 2 009 workers of an automobile foundry in Shiyan, Hubei province were recruited in the study, 1 300 at eight worksites including sand preparation, cast shakeout, and finishing, melting, moulding, core-making, overhead crane operation and pouring as exposed group, and the other 709 auxiliary workers at the same factory, such as electricians, inspectors, fitters, and so on, as control group. Person-years of observation were calculated by persons observed and years followed-up for each of them. Person-year incidence of silicosis and its relative risk （RR） or odds ratio （OR） and 95% confidence intervals （CI） among the workers were estimated, adjusted for relevant factors with logistic regression model using SPSS version 15.0 software. Results Totally, 2 009 workers were followed-up for 37 151 person-years and 48 cases of silicosis were found, with an overall incidence of 1.34 per thousand, 2.02 per thousand in exposed group, and 0.15 per thousand in control one. Risk of silicosis was significantly higher in the exposed group than that in the control one （RR=13.13, 95% CI 3.18-54.13）, higher in men than that in women （RR=13.92, 95% CI 1.92-100.93）. Risks of silicosis varied by job, highest in those exposed to cast shakeout and finishing （RR=28.14, 95% CI 6.43-123.11）, followed by those exposed to pouring （RR-22.23, 95% CI 5.01-98.55） in the foundry. Average length of employment at onset of silicosis was 25.94 years, and silicosis incidence increased with length of employment. Average age at onset of silicosis was 47.83 years old. The risk of silicosis in workers with pulmonary tuberculosis was 2.57 folds as those without it （P〈0.01）. Ten deaths were recorded in those with silicosis, with a case-fatality rate of 20.83 percent three of them died of lung cancer, three of liver cancer, two of ischemic heart disease, and two of other diseases as their immediate causes of death. Incidence of silicosis in foundry workers positively correlated with their cumulative silica exposure （OR-3.00, 95% CI 2.34-3.83）. Risks of silicosis increased by 4.38 folds with an increase of 1 mg/m^3-year of cumulative silica exposure, and by 3.79 folds with smoking, respectively, adjusted for alcohol drinking and age. Based on a logistic regression model fitted, incidence of silicosis is expected to be 44.6 per thousand for those with daily exposure to silica of 4.18 mg/m^3 in average for 30 years, and if incidence of silicosis is expected to be less than 1 per thousand, daily exposure to silica should be controlled below 0.2 mg/m^3 for those with 20 years of employment, or below 0.1 mg/m^3 for those with 30 or 40 years of silica exposure. Conclusions At present, foundry workers in China still face high risk of developing silicosis. For lowering occurrence of silicosis in exposed workers, it seems necessary that current occupational exposure limits for silica at worksites in China should be reexamined and silica dust control measures be strengthend.展开更多
Current energy conservation and emissions reduction strategies in iron and steel industry were reviewed. Since foundry industry is one of the major source of energy consumption and pollution emission (especially CO 2 ...Current energy conservation and emissions reduction strategies in iron and steel industry were reviewed. Since foundry industry is one of the major source of energy consumption and pollution emission (especially CO 2 ), issues concerning energy-saving and emission-reduction have been raised by governments and the industry. Specialists from around the world carried out multidimensional analyses and evaluation on the potentials in energy conservation and emissions reduction in iron and steel industry, and proposed various kinds of analyzing models. The primary measures mainly focus on the targeted policies formulation and also on clean and highefficient technologies development. The differences and similarities in energy conservation and emission reduction in foundry industry between China and other countries were discussed, while, the future development trend was also pointed out.展开更多
Additive manufacturing is expected to transform and upgrade the traditional foundry industry to realize the integrated manufacturing and rapid and low-cost development of high-performance components with complex shape...Additive manufacturing is expected to transform and upgrade the traditional foundry industry to realize the integrated manufacturing and rapid and low-cost development of high-performance components with complex shapes.The additive manufacturing technology commonly applied in casting mold preparation(fusible molds,sand molds/cores and ceramic cores)mainly includes selective laser sintering(SLS)and binder injection three-dimensional printing(3DP).In this work,the research status of SLS/3DP-casting processes on material preparation,equipment development,process optimization,simulation and application cases in aerospace,automotive and other fields were elaborated.Finally,the developing trends of the additive manufacturing technology in the future of foundry field are introduced,including multi-material sand molds(metal core included),ceramic core-shell integration and die-casting dies with conformal cooling runners.展开更多
为打造智能蒙华生态圈,统一的企业级云开发与运行环境是必不可少的。利用Cloud Foundry的开源云架构,从多种角度与层次上研究设计了开发平台的架构,构建一个架构柔性、功能完备、性能卓越、自我诊断、自我调优和方便易用的统一应用开发...为打造智能蒙华生态圈,统一的企业级云开发与运行环境是必不可少的。利用Cloud Foundry的开源云架构,从多种角度与层次上研究设计了开发平台的架构,构建一个架构柔性、功能完备、性能卓越、自我诊断、自我调优和方便易用的统一应用开发平台。平台提供企业级服务,具有平台即服务(PaaS,Platform as a Service)和数据即服务(DaaS,Date as a Service)的特性,可实现快速开发、快速部署和云应用快速集成,使用者可以不懂安装配置应用的方法,也可以方便快捷地在开发平台上找到需要的服务来创建、部署和管理所需的应用程序。展开更多
基金Project(2011006B)supported by the Open Project of National Engineering Research Center of Near-Shape Forming for Metallic Materials,ChinaProject(FJ)supported by the CAS"100 talents"Plan
文摘A numerical model of foundry filling process was established based on the smoothed particle hydrodynamics（SPH）method.To mimic the constraints that the solid mold prescribes on the filling fluid,a composite treatment to the solid boundaries is elaborately designed.On solid boundary surfaces,boundary particles were set,which exert Lennard-Jones force on approaching fluid particles;inside the solid mold,ghost particles were arranged to complete the compact domain of near-boundary fluid particles.Water analog experiments were conducted in parallel with the model simulations.Very good agreement between experimental and simulation results demonstrates the success of model development.
文摘In Burkina Faso, one of the three largest gold producers in West Africa, foundry activity is often paralyzed when basic equipment such as crucibles and cups are not available or should be imported. However, previous studies have shown the availability of kaolinite-rich clay resources that could be used for the local manufacture of silico-aluminous ceramic crucibles. This work allowed to manufacture industrial ceramic crucibles with local clays and then they were tested in foundry industry. The materials were manufactured from three (03) raw materials including two clays (SAB and ROU) and sand. The chemical and mineral analysis has shown that the raw materials are suitable for the formulation of refractory materials. The results of characterization of the materials formulated showed that the properties of use are appreciable. The porosity of the materials is relatively low (23 - 28 vol%) with a diametral compressive strength between 0.61 and 1.34 MPa. Crucibles sintered at 1250˚C with a stay of 2 hours have a mechanical strength capable of supporting the weight of the ores contained. These crucibles have a refractoriness under load (T0.5) above 1141˚C and resist chemical attacks. Tests were carried out in the industry at 1100˚C, and the results were satisfactory.
文摘本文介绍了VMware近期新推出的一个开源PaaS项目:Cloud Foundry。PaaS是Platform as a Service的缩写,意思是平台即服务。PaaS将软件部署,运行和维护整合成一种服务,以SaaS(Software as a Service软件即服务)的模式提交给开发人员。开发人员可以快速地在其上进行软件开发部署,运行和扩展,而不用去搭建和维护硬件设施,安装软件中间件。将开发人员从软件部署,运行和维护软件的工作中解脱出来。本文指出了现代软件系统的新特点及遇到的挑战,介绍了PaaS的概念、Cloud Foundry的架构,分析了Cloud Foundry与业界现有几款PaaS相比的优点。最后,对PaaS未来的发展方向做了展望。
基金supported by the Program for New Century Excellent Talents in University(No.NCET-09-0396)the Fundamental Research Funds for the Central Universities(2011TS039)+1 种基金the National Science&Technology Key Projects of Numerical Control(2012ZX04012-011)the HUST self-determined and Innovative Research Funds for National Defense(2011)
文摘PPDB issues-four aspects of current management issues of foundry enterprises are discussed in this paper,including Production Management,Process Control,Duration Monitoring and Business Intelligence Data Analysis.Also a whole Enterprise Resource Planning(ERP) solution for foundry enterprises is proposed.The solution contains many models,four of which are used to solve the PPDB issues.These are called SPDB models,which separately are the Single-piece management model(based on casting lifecycle),Process management model(based on task-driven technology),Duration monitoring model(based on surplus period),and Business intelligence data analysis model(based on data mining).An ERP system for foundry enterprises,named HZERP,was researched and developed,and applied to a sand casting company of single piece and small batch production.Qualitatively and quantitatively comparing the application effect before and after implementing the HZERP system,the result demonstrated that the foundry ERP system based on the SPDB models can help metal casting enterprises achieve the single-piece management,better regulate the production processes,improve production and delivery management,shorten the production cycle,reduce costs,and speed up the capital turnover to a large extent.
文摘Objectives The purposes were to determine the relationship between silicosis among foundry workers and their cumulative exposure to silica dust, and to establish a regression model to predict the risk for developing silicosis by a given length of employment and air concentrations of silica at worksites. Methods A 29-year cohort study was conducted, including all those employed for more than one year during January 1, 1980 to December 31, 1996 and all members of the cohort were followed-up to December 3 1, 2008. In total, 2 009 workers of an automobile foundry in Shiyan, Hubei province were recruited in the study, 1 300 at eight worksites including sand preparation, cast shakeout, and finishing, melting, moulding, core-making, overhead crane operation and pouring as exposed group, and the other 709 auxiliary workers at the same factory, such as electricians, inspectors, fitters, and so on, as control group. Person-years of observation were calculated by persons observed and years followed-up for each of them. Person-year incidence of silicosis and its relative risk （RR） or odds ratio （OR） and 95% confidence intervals （CI） among the workers were estimated, adjusted for relevant factors with logistic regression model using SPSS version 15.0 software. Results Totally, 2 009 workers were followed-up for 37 151 person-years and 48 cases of silicosis were found, with an overall incidence of 1.34 per thousand, 2.02 per thousand in exposed group, and 0.15 per thousand in control one. Risk of silicosis was significantly higher in the exposed group than that in the control one （RR=13.13, 95% CI 3.18-54.13）, higher in men than that in women （RR=13.92, 95% CI 1.92-100.93）. Risks of silicosis varied by job, highest in those exposed to cast shakeout and finishing （RR=28.14, 95% CI 6.43-123.11）, followed by those exposed to pouring （RR-22.23, 95% CI 5.01-98.55） in the foundry. Average length of employment at onset of silicosis was 25.94 years, and silicosis incidence increased with length of employment. Average age at onset of silicosis was 47.83 years old. The risk of silicosis in workers with pulmonary tuberculosis was 2.57 folds as those without it （P〈0.01）. Ten deaths were recorded in those with silicosis, with a case-fatality rate of 20.83 percent three of them died of lung cancer, three of liver cancer, two of ischemic heart disease, and two of other diseases as their immediate causes of death. Incidence of silicosis in foundry workers positively correlated with their cumulative silica exposure （OR-3.00, 95% CI 2.34-3.83）. Risks of silicosis increased by 4.38 folds with an increase of 1 mg/m^3-year of cumulative silica exposure, and by 3.79 folds with smoking, respectively, adjusted for alcohol drinking and age. Based on a logistic regression model fitted, incidence of silicosis is expected to be 44.6 per thousand for those with daily exposure to silica of 4.18 mg/m^3 in average for 30 years, and if incidence of silicosis is expected to be less than 1 per thousand, daily exposure to silica should be controlled below 0.2 mg/m^3 for those with 20 years of employment, or below 0.1 mg/m^3 for those with 30 or 40 years of silica exposure. Conclusions At present, foundry workers in China still face high risk of developing silicosis. For lowering occurrence of silicosis in exposed workers, it seems necessary that current occupational exposure limits for silica at worksites in China should be reexamined and silica dust control measures be strengthend.
基金supported by Guangdong Major Science and Technology Specific Project, grant number2008A080800022
文摘Current energy conservation and emissions reduction strategies in iron and steel industry were reviewed. Since foundry industry is one of the major source of energy consumption and pollution emission (especially CO 2 ), issues concerning energy-saving and emission-reduction have been raised by governments and the industry. Specialists from around the world carried out multidimensional analyses and evaluation on the potentials in energy conservation and emissions reduction in iron and steel industry, and proposed various kinds of analyzing models. The primary measures mainly focus on the targeted policies formulation and also on clean and highefficient technologies development. The differences and similarities in energy conservation and emission reduction in foundry industry between China and other countries were discussed, while, the future development trend was also pointed out.
基金the Principle and Method of Integrated Laser 3D Printing of Metal Core-Variable Area Performance Complex Sand Mold(Grant No.U1808216)the Aero Engine and Gas Turbine Major Special Fundamental Research Fund Project(2017-Ⅶ-0008-0102)。
文摘Additive manufacturing is expected to transform and upgrade the traditional foundry industry to realize the integrated manufacturing and rapid and low-cost development of high-performance components with complex shapes.The additive manufacturing technology commonly applied in casting mold preparation(fusible molds,sand molds/cores and ceramic cores)mainly includes selective laser sintering(SLS)and binder injection three-dimensional printing(3DP).In this work,the research status of SLS/3DP-casting processes on material preparation,equipment development,process optimization,simulation and application cases in aerospace,automotive and other fields were elaborated.Finally,the developing trends of the additive manufacturing technology in the future of foundry field are introduced,including multi-material sand molds(metal core included),ceramic core-shell integration and die-casting dies with conformal cooling runners.
文摘为打造智能蒙华生态圈,统一的企业级云开发与运行环境是必不可少的。利用Cloud Foundry的开源云架构,从多种角度与层次上研究设计了开发平台的架构,构建一个架构柔性、功能完备、性能卓越、自我诊断、自我调优和方便易用的统一应用开发平台。平台提供企业级服务,具有平台即服务(PaaS,Platform as a Service)和数据即服务(DaaS,Date as a Service)的特性,可实现快速开发、快速部署和云应用快速集成,使用者可以不懂安装配置应用的方法,也可以方便快捷地在开发平台上找到需要的服务来创建、部署和管理所需的应用程序。
