The agility and the flexibility of the current shop floor control systems have been limited so far, owing to the lack of structural flexibility and agility in its control software layer. Most of them are based on trad...The agility and the flexibility of the current shop floor control systems have been limited so far, owing to the lack of structural flexibility and agility in its control software layer. Most of them are based on traditional hierarchical architecture and the top down approach and depend structurally on their specific configuration and job scheduling. Not only can they hardly satisfactorily adapt to these increasing changes and disturbances, but also make the redevelopment and maintenance of shop floor control system (SFCS) to need high cost and much time. And SFCS based on the heterarchical architecture don′t provide a predictable and high performance system, especially not in the heterogeneous environments, where the resources are scarce and the current decisions have serious repercussions on the future performances. For this reason, the heterarchical control is hardly applied in industry. Obviously, it is necessary to develop a new structural framework of reconfigurable SFCS to improve their agility, flexibility and maintainability. This paper presents a holonic framework of reconfigurable SFCS based on holonic manufacturing concepts. The framework is composed of resource holons, product holons and other staff holons. The model of each holon and the co operative mechanisms of holons are described. To verify the proposed approach experimentally, a prototype reconfigurable SFCS for a flexible manufacturing shop floor producing discrete parts is implemented.展开更多
Based on the discussion of functions, components, control structure and network computing architecture of generic shop floor control (GSFC) in computer integrated manufacturing system (CIMS), the internal integrati...Based on the discussion of functions, components, control structure and network computing architecture of generic shop floor control (GSFC) in computer integrated manufacturing system (CIMS), the internal integration between components of GSFC and the external integration between GSFC and the other components of CIMS are studied. The integration models on the aspects of function, information, processing and interface are put forward. The integration models and the methods are implemented and applied in CIMS projects successfully.展开更多
This paper presents a further improved Production Activity Control Architecture to deal with the complexity of information by creating Sub-Producers and Sub-Movers which will not only give a better control at workstat...This paper presents a further improved Production Activity Control Architecture to deal with the complexity of information by creating Sub-Producers and Sub-Movers which will not only give a better control at workstation level but also reduce load on the Dispatcher. It also makes an analysis of the basic and improved PAC (Production Activity Control) Architecture in the Control System for Integrated Manufacturing. The PAC Architecture and the improvement will further enhance the flexibility and adaptability of the architecture in the ever changing environment of the Shop Floor Control (SFC) Systems.展开更多
Shop floor control （SFC） is responsible for the coordination and control of the manufacturing physical and information flow within the shop floor in the manufacturing system. Weaknesses of the production activity co...Shop floor control （SFC） is responsible for the coordination and control of the manufacturing physical and information flow within the shop floor in the manufacturing system. Weaknesses of the production activity control （PAC） architecture of the shop floor are addressed by the Maglica＇s new system architecture. This architecture gives rise to unlimited number of movers and producers thus evolving more complex but decentralized architecture. Beijing Institute of Technology - production activity control （BIT-PAC） architecture introduces an idea of sub-producars and sub-movers thus reducing the complexity of the architecture. All the equipments including sub-producars and sub-movers are considered to be passive in the proposed shop floor information system. The dissemination of information from sub-producers and sub-movers is done manually through a PC. Proposed BIT-PAC SFC architecture facilitates the information flow from shop floor to the other area of the organization. Effective use of interact information services （IIS） and SQL2000 is done along with the ASP.NET technology to implement the application logic. Applicability of the software based on BIT-PAC architecture is checked by running application software on a network PC that supports the dynamic flow of information from sub-producers and sub-movers to the other parts of the organization. Use of software is also shown at the end for BIT training workshop thus supporting the use of SFC architecture for similar kind of environments.展开更多
Manufacturing system, with high level of complexity and with a mix of semi-repetitive and repetitive products, to become productive, should seek the standardization of products and processes to obtain the optimization...Manufacturing system, with high level of complexity and with a mix of semi-repetitive and repetitive products, to become productive, should seek the standardization of products and processes to obtain the optimization of use of production resources. However, it is necessary to measure the productivity, so that the system of measurement and control of manufacturing processes are an element critical as to ensure greater visibility of the flow＇s restrictions, minimized when detected properly. In this case, the automation of factory＇s measurement process can effectively contribute to ensuring the effectiveness of the function control of a manufacturing system. It is important to consider that the automation of the system of measurement and control of manufacturing processes, of complex environment, is heavily dependent of IT tools applied directly in the interface computational between the operation systems and the corporate systems. This heavy reliance, if exploited technically properly, allows that automation of the system of measurement and control of production makes the access to time real of availability of manufacturing process＇s data, such as processing time and setup time that it can export to a specialist software in programming production, for example, feasible. In this paper, the automation of the system of measurement and control of production is approached, in order to identify the main possibilities of the design of an information system capable to integrate the flow of information in an environment internal on manufacturing organizations, with emphasis in the digital manufacturing paradigm.展开更多
The movement principle of sidewalls and floor of extraction opening is analyzed, it is found that floor heave not only has something to do with the floor strata, but sidewalls. The effect of sidewall anchor and corner...The movement principle of sidewalls and floor of extraction opening is analyzed, it is found that floor heave not only has something to do with the floor strata, but sidewalls. The effect of sidewall anchor and corner anchor is studied, the mechanical principle of reinforcing sidewalls and corners is put forward and applied in engineering practice.展开更多
Adopting distributed control architecture is the important developmentdirection for shop floor management and control system, is also the requirement of making it agile,intelligent and concurrent. Some key problems in...Adopting distributed control architecture is the important developmentdirection for shop floor management and control system, is also the requirement of making it agile,intelligent and concurrent. Some key problems in achieving distributed control architecture areresearched. An activity model of shop floor is presented as the requirement definition of theprototype system. The multi-agent based software architecture is constructed. How the core part inshop floor management and control system, production plan and scheduling is achieved. Thecooperation of different agents is illustrated. Finally, the implementation of the prototype systemis narrated.展开更多
The effect of reinforcing roof, sides and floor corners to control floor heave of extraction opening was analyzed, It was proved by engineering practice and numerical simulation that reinforcing any part of surroundin...The effect of reinforcing roof, sides and floor corners to control floor heave of extraction opening was analyzed, It was proved by engineering practice and numerical simulation that reinforcing any part of surrounding rock have certainly control effect for floor heave, in the basis of this, the new way that roof, sides and floor corners were rein-forced to control floor heave was put forward. Contrasting control result of reinforcing floor with this, it is determined that reinforcing is more suitable to control floor heave of extrac-tion opening than reinforcing floor when advancing abutment pressure is in some range.展开更多
Floor heave of a roadway is a dynamic phenomenon that often happens in the roadways of coal mines. It seriously affects safe production in the coal mine. Floor heave has long been one of the most difficult problems to...Floor heave of a roadway is a dynamic phenomenon that often happens in the roadways of coal mines. It seriously affects safe production in the coal mine. Floor heave has long been one of the most difficult problems to be resolved during coal mining. An analysis of floor heave in the soft rock surrounding the roadway, and the factors influencing it, allowed the deformation mechanism in the west wing double track haulage roadway of the Tingnan Coal Mine to be deduced. Three types of floor heave are observed there: intumescent floor heave, extrusion and mobility floor heave, and compound floor heave. Control measures are proposed that have been adopted during a recent repair engineering project. Control of the floor heave in the west wing track haulage roadway was demonstrated. The reliability and rationality of a combined support technology including floor anchors, an inverted arch, and anchoring of both sides was verified by mine pressure data and the field observations. Waterproofing measures were also under-taken to assist in the control of floor heave.展开更多
A new approach named as steel pile method is innovatively proposed in this study to control severe floor heaves in gob-side entry retaining. It is required that the steel piles be installed in the floor corners with a...A new approach named as steel pile method is innovatively proposed in this study to control severe floor heaves in gob-side entry retaining. It is required that the steel piles be installed in the floor corners with a certain interval before the influence of the dynamic pressure induced by current panel extraction. Using numerical simulation and theoretical analysis, this study investigated the interaction between the steel piles and the floor rocks during the service life of the steel piles, and revealed the mechanism of the steel piles in controlling floor heaves. The effect of the steel pile parameters on the control of floor heaves was presented and elaborated. It is found that the effectiveness of the steel piles in controlling floor heaves can be enhanced with greater installed dip angle, longer length and smaller interval of the steel piles.Compared with traditional methods, e.g., using floor anchor bolts and floor restoration, the advantages using steel pile were successfully defined in terms of controlling effect and economic benefits. It is hoped that the proposed method can contribute to the development of gob-side entry retaining technique.展开更多
Based on in-mine instrumentation and theoretical analysis of the unsymmetrical large-deformation that occurred in the roadway after excavation,Differential Floor Heave(DFH)was found to be the main reason for roadway f...Based on in-mine instrumentation and theoretical analysis of the unsymmetrical large-deformation that occurred in the roadway after excavation,Differential Floor Heave(DFH)was found to be the main reason for roadway failure.It needs to be pointed out that the specific roadway was driven in inclined rock strata.In addition,the factors that contribute to the occurrence of DFH are discussed in detail.It is believed that DFH is triggered by the unsymmetrical stress distribution in the floor and the different rock types encountered near the two floor corners.Hence,DFH control should be focused on the left floor corner where shearing failure occurs initially and the left floor surface where tensile failure is more severe.The proposed DFH control strategies include unsymmetrical grouting for the whole roadway,re-design of the roof and ribs support,reinforcement of the weak zones,and release of the concentrated stress in the earlier stage.Meanwhile,it is recommended that in the later stage,both bolts and cable bolts with higher strength and the backfilling technique using the coal measure rocks and concrete should be employed in the reversed-arch floor.The field instrumentation results,after using the proposed control strategies,indicate that large deformation in a DFH roadway has been successfully controlled.展开更多
Floor heave is one of difficult problems in strata contro around roadways. The main influence fectors, mechanism and types of floor heave are analysed;reinforcement methods such as closed suppoort with an inverted arc...Floor heave is one of difficult problems in strata contro around roadways. The main influence fectors, mechanism and types of floor heave are analysed;reinforcement methods such as closed suppoort with an inverted arch,floor bolting and floor grouting, and destressing trough precut over the top of a chamber are introduced.展开更多
The planning and scheduling in real shop floor is actually achieved by coordination between different persons. In this process, cooperation is mainstream, but competition also exists, for example, the competition betw...The planning and scheduling in real shop floor is actually achieved by coordination between different persons. In this process, cooperation is mainstream, but competition also exists, for example, the competition between different groups, operators with the same skill, etc. In multi-agent based shop floor management and control system, this competition and cooperation relation must be embodied. The general process of shop floor production planning and scheduling is studied, and a colored Petri-net model for the competition and cooperation process of three main agents in such system to achieve shop floor production planning and scheduling is presented. The evaluating method of bids in bidding process that especially embodies the competition relationship is also presented. This colored Petri-net model gives a clear illustration of this complex coordination process to system designers, effectively promotes the cooperative development.展开更多
In order to overcome the weakness of the former production activity control （PAC） architecture, this paper presents an improved PAC architecture. The BIT-PAC architecture has been applied with the use of information...In order to overcome the weakness of the former production activity control （PAC） architecture, this paper presents an improved PAC architecture. The BIT-PAC architecture has been applied with the use of information technology. It facilitates the information flow from Shop Floor to other areas of the organization and makes the organizations more integrated and productive. This architecture also facilitates the expansion of the Shop Floor functions without disturbing the basic infrastructure. Effectiveness of the BIT-PAC architecture was checked by developing and running application software on a network PC which has supported the dynamic flow of information from Sub-Producers and Sub-Movers to other areas of organization.展开更多
The increasing strength of new structural materials and the span of new structures, accompanied by aesthetic requirements for greater slenderness, are resulting in more applications of long-span structures. In this pa...The increasing strength of new structural materials and the span of new structures, accompanied by aesthetic requirements for greater slenderness, are resulting in more applications of long-span structures. In this paper, serviceability control technology and its design theory are studied. First, a novel tuned mass damper （TMD） with controllable stiffness is developed. Second, methods for modeling human-induced loads are proposed, including standing up, walking, jumping and running, and an analysis method for long-span floor response is proposed based on a finite element model. Third, a design method for long-span floors installed with a multiple TMD （MTMD） system considering human comfort is introduced, largely based on a study of existing literature. Finally, a design, analysis and field test is conducted using several large scale buildings in China including the Beijing Olympic Park National Conference Center, Changsha New Railway Station and the Xi＇an Northern Railway Station. The analytical and field test results show that the MTMD system designed using the proposed method is capable of effectively mitigating the vertical vibration of long-span floor structures. The study presented in this paper provides an important reference for the analysis of vibration serviceability of similar long-span floors and design of control system for these structures.展开更多
A limestone mine in Ohio has had instability problems that have led to massive roof falls extending to the surface. This study focuses on the role that weak, moisture-sensitive floor has in the instability issues.Prev...A limestone mine in Ohio has had instability problems that have led to massive roof falls extending to the surface. This study focuses on the role that weak, moisture-sensitive floor has in the instability issues.Previous NIOSH research related to this subject did not include analysis for weak floor or weak bands and recommended that when such issues arise they should be investigated further using a more advanced analysis. Therefore, to further investigate the observed instability occurring on a large scale at the Ohio mine, FLAC3 D numerical models were employed to demonstrate the effect that a weak floor has on roof and pillar stability. This case study will provide important information to limestone mine operators regarding the impact of weak floor causing the potential for roof collapse, pillar failure, and subsequent subsidence of the ground surface.展开更多
A floor heating system is a traditionary famous in Asian countries, especially in North East of China and Korea. In this report, we intended to clarify the effect of floor hating system for accessing a peripheral leuk...A floor heating system is a traditionary famous in Asian countries, especially in North East of China and Korea. In this report, we intended to clarify the effect of floor hating system for accessing a peripheral leukocyte regulation in winter season by evidence-based manner more than VAS. We set up two different office rooms heat-controlled by floor heating and air-conditioned by ceiling electric heater. Both qualitative and quantitative approaches determine which are better therapeutic effective recipes for this trial. The elements were evaluated by the total number of peripheral leukocyte, granulocyte and lymphocyte ratio and lymphocyte subsets. For 5 days of working in each conditioned room, the volunteers were changed the room after one-week interval for cooling down. Floor heating system regulated total number of peripheral leukocyte. The mode of the action for the high number of the volunteer was down-regulated. On the contrary, in lower numbers it was up-regulated after the trial. The number of leukocyte subsets, granulocyte and lymphocyte were also regulated by dose dependent manner. Emotional hormone, adrenalin, cortisone and nor-adrenaline were down regulated by floor heating but dopamine was up-regulated by this heating system. The reversal results were obtained by the group who worked in the conditioned room by the system heating from ceiling.展开更多
文摘The agility and the flexibility of the current shop floor control systems have been limited so far, owing to the lack of structural flexibility and agility in its control software layer. Most of them are based on traditional hierarchical architecture and the top down approach and depend structurally on their specific configuration and job scheduling. Not only can they hardly satisfactorily adapt to these increasing changes and disturbances, but also make the redevelopment and maintenance of shop floor control system (SFCS) to need high cost and much time. And SFCS based on the heterarchical architecture don′t provide a predictable and high performance system, especially not in the heterogeneous environments, where the resources are scarce and the current decisions have serious repercussions on the future performances. For this reason, the heterarchical control is hardly applied in industry. Obviously, it is necessary to develop a new structural framework of reconfigurable SFCS to improve their agility, flexibility and maintainability. This paper presents a holonic framework of reconfigurable SFCS based on holonic manufacturing concepts. The framework is composed of resource holons, product holons and other staff holons. The model of each holon and the co operative mechanisms of holons are described. To verify the proposed approach experimentally, a prototype reconfigurable SFCS for a flexible manufacturing shop floor producing discrete parts is implemented.
文摘Based on the discussion of functions, components, control structure and network computing architecture of generic shop floor control (GSFC) in computer integrated manufacturing system (CIMS), the internal integration between components of GSFC and the external integration between GSFC and the other components of CIMS are studied. The integration models on the aspects of function, information, processing and interface are put forward. The integration models and the methods are implemented and applied in CIMS projects successfully.
文摘This paper presents a further improved Production Activity Control Architecture to deal with the complexity of information by creating Sub-Producers and Sub-Movers which will not only give a better control at workstation level but also reduce load on the Dispatcher. It also makes an analysis of the basic and improved PAC (Production Activity Control) Architecture in the Control System for Integrated Manufacturing. The PAC Architecture and the improvement will further enhance the flexibility and adaptability of the architecture in the ever changing environment of the Shop Floor Control (SFC) Systems.
基金This project is supported by Beijing City Key Discipline Fund, China (No.XK100070424).
文摘Shop floor control （SFC） is responsible for the coordination and control of the manufacturing physical and information flow within the shop floor in the manufacturing system. Weaknesses of the production activity control （PAC） architecture of the shop floor are addressed by the Maglica＇s new system architecture. This architecture gives rise to unlimited number of movers and producers thus evolving more complex but decentralized architecture. Beijing Institute of Technology - production activity control （BIT-PAC） architecture introduces an idea of sub-producars and sub-movers thus reducing the complexity of the architecture. All the equipments including sub-producars and sub-movers are considered to be passive in the proposed shop floor information system. The dissemination of information from sub-producers and sub-movers is done manually through a PC. Proposed BIT-PAC SFC architecture facilitates the information flow from shop floor to the other area of the organization. Effective use of interact information services （IIS） and SQL2000 is done along with the ASP.NET technology to implement the application logic. Applicability of the software based on BIT-PAC architecture is checked by running application software on a network PC that supports the dynamic flow of information from sub-producers and sub-movers to the other parts of the organization. Use of software is also shown at the end for BIT training workshop thus supporting the use of SFC architecture for similar kind of environments.
文摘Manufacturing system, with high level of complexity and with a mix of semi-repetitive and repetitive products, to become productive, should seek the standardization of products and processes to obtain the optimization of use of production resources. However, it is necessary to measure the productivity, so that the system of measurement and control of manufacturing processes are an element critical as to ensure greater visibility of the flow＇s restrictions, minimized when detected properly. In this case, the automation of factory＇s measurement process can effectively contribute to ensuring the effectiveness of the function control of a manufacturing system. It is important to consider that the automation of the system of measurement and control of manufacturing processes, of complex environment, is heavily dependent of IT tools applied directly in the interface computational between the operation systems and the corporate systems. This heavy reliance, if exploited technically properly, allows that automation of the system of measurement and control of production makes the access to time real of availability of manufacturing process＇s data, such as processing time and setup time that it can export to a specialist software in programming production, for example, feasible. In this paper, the automation of the system of measurement and control of production is approached, in order to identify the main possibilities of the design of an information system capable to integrate the flow of information in an environment internal on manufacturing organizations, with emphasis in the digital manufacturing paradigm.
文摘The movement principle of sidewalls and floor of extraction opening is analyzed, it is found that floor heave not only has something to do with the floor strata, but sidewalls. The effect of sidewall anchor and corner anchor is studied, the mechanical principle of reinforcing sidewalls and corners is put forward and applied in engineering practice.
基金This project is supported by National Natural Science Foundation of China(No.50105006,No.59990470)(No.2001AA412140).
文摘Adopting distributed control architecture is the important developmentdirection for shop floor management and control system, is also the requirement of making it agile,intelligent and concurrent. Some key problems in achieving distributed control architecture areresearched. An activity model of shop floor is presented as the requirement definition of theprototype system. The multi-agent based software architecture is constructed. How the core part inshop floor management and control system, production plan and scheduling is achieved. Thecooperation of different agents is illustrated. Finally, the implementation of the prototype systemis narrated.
基金Supported by the Natural Science Foundation Project of Hunan(01JJY3020)
文摘The effect of reinforcing roof, sides and floor corners to control floor heave of extraction opening was analyzed, It was proved by engineering practice and numerical simulation that reinforcing any part of surrounding rock have certainly control effect for floor heave, in the basis of this, the new way that roof, sides and floor corners were rein-forced to control floor heave was put forward. Contrasting control result of reinforcing floor with this, it is determined that reinforcing is more suitable to control floor heave of extrac-tion opening than reinforcing floor when advancing abutment pressure is in some range.
基金grateful to the Key Program of the National Natural Science Foundation of China (Nos. 51134005, 40972196, and 41172263) for financing this research
文摘Floor heave of a roadway is a dynamic phenomenon that often happens in the roadways of coal mines. It seriously affects safe production in the coal mine. Floor heave has long been one of the most difficult problems to be resolved during coal mining. An analysis of floor heave in the soft rock surrounding the roadway, and the factors influencing it, allowed the deformation mechanism in the west wing double track haulage roadway of the Tingnan Coal Mine to be deduced. Three types of floor heave are observed there: intumescent floor heave, extrusion and mobility floor heave, and compound floor heave. Control measures are proposed that have been adopted during a recent repair engineering project. Control of the floor heave in the west wing track haulage roadway was demonstrated. The reliability and rationality of a combined support technology including floor anchors, an inverted arch, and anchoring of both sides was verified by mine pressure data and the field observations. Waterproofing measures were also under-taken to assist in the control of floor heave.
基金Financial supports for this work,provided by the National Natural Science Foundation of China(Nos.511204167 and 51574227)Chinese National Programs for Fundamental Research and Development(No.2013CB227905),are gratefully acknowledged
文摘A new approach named as steel pile method is innovatively proposed in this study to control severe floor heaves in gob-side entry retaining. It is required that the steel piles be installed in the floor corners with a certain interval before the influence of the dynamic pressure induced by current panel extraction. Using numerical simulation and theoretical analysis, this study investigated the interaction between the steel piles and the floor rocks during the service life of the steel piles, and revealed the mechanism of the steel piles in controlling floor heaves. The effect of the steel pile parameters on the control of floor heaves was presented and elaborated. It is found that the effectiveness of the steel piles in controlling floor heaves can be enhanced with greater installed dip angle, longer length and smaller interval of the steel piles.Compared with traditional methods, e.g., using floor anchor bolts and floor restoration, the advantages using steel pile were successfully defined in terms of controlling effect and economic benefits. It is hoped that the proposed method can contribute to the development of gob-side entry retaining technique.
基金financially supported by the National Natural Science Foundation of China (Nos.51204166 and 51174195)the Graduate Student Research Innovation Project of Ordinary University in Jiangsu Province (2013) (No.CXLX13_952)
文摘Based on in-mine instrumentation and theoretical analysis of the unsymmetrical large-deformation that occurred in the roadway after excavation,Differential Floor Heave(DFH)was found to be the main reason for roadway failure.It needs to be pointed out that the specific roadway was driven in inclined rock strata.In addition,the factors that contribute to the occurrence of DFH are discussed in detail.It is believed that DFH is triggered by the unsymmetrical stress distribution in the floor and the different rock types encountered near the two floor corners.Hence,DFH control should be focused on the left floor corner where shearing failure occurs initially and the left floor surface where tensile failure is more severe.The proposed DFH control strategies include unsymmetrical grouting for the whole roadway,re-design of the roof and ribs support,reinforcement of the weak zones,and release of the concentrated stress in the earlier stage.Meanwhile,it is recommended that in the later stage,both bolts and cable bolts with higher strength and the backfilling technique using the coal measure rocks and concrete should be employed in the reversed-arch floor.The field instrumentation results,after using the proposed control strategies,indicate that large deformation in a DFH roadway has been successfully controlled.
文摘Floor heave is one of difficult problems in strata contro around roadways. The main influence fectors, mechanism and types of floor heave are analysed;reinforcement methods such as closed suppoort with an inverted arch,floor bolting and floor grouting, and destressing trough precut over the top of a chamber are introduced.
基金Supported partly by the Hi-tech Program of China( China86 3) ( No.86 3-5 11-943-0 0 9) and the National Natural Sci-ence Foundation of China( No.5 9990 470 )
文摘The planning and scheduling in real shop floor is actually achieved by coordination between different persons. In this process, cooperation is mainstream, but competition also exists, for example, the competition between different groups, operators with the same skill, etc. In multi-agent based shop floor management and control system, this competition and cooperation relation must be embodied. The general process of shop floor production planning and scheduling is studied, and a colored Petri-net model for the competition and cooperation process of three main agents in such system to achieve shop floor production planning and scheduling is presented. The evaluating method of bids in bidding process that especially embodies the competition relationship is also presented. This colored Petri-net model gives a clear illustration of this complex coordination process to system designers, effectively promotes the cooperative development.
文摘In order to overcome the weakness of the former production activity control （PAC） architecture, this paper presents an improved PAC architecture. The BIT-PAC architecture has been applied with the use of information technology. It facilitates the information flow from Shop Floor to other areas of the organization and makes the organizations more integrated and productive. This architecture also facilitates the expansion of the Shop Floor functions without disturbing the basic infrastructure. Effectiveness of the BIT-PAC architecture was checked by developing and running application software on a network PC which has supported the dynamic flow of information from Sub-Producers and Sub-Movers to other areas of organization.
基金National Natural Science Foundation of China Under Grant No.51178100Foundation of the Priority Sciences Development Program of Higher Education Institutions of Jiangsu Province Under Grant No.1105007001+1 种基金Teaching and Research Foundation for Excellent Young Teachers of Southeast University Under Grant No.3205001205Scientific Research Foundation the Scientific Research Foundation of Graduate School of Southeast University Under Grant No.YBJJ1006
文摘The increasing strength of new structural materials and the span of new structures, accompanied by aesthetic requirements for greater slenderness, are resulting in more applications of long-span structures. In this paper, serviceability control technology and its design theory are studied. First, a novel tuned mass damper （TMD） with controllable stiffness is developed. Second, methods for modeling human-induced loads are proposed, including standing up, walking, jumping and running, and an analysis method for long-span floor response is proposed based on a finite element model. Third, a design method for long-span floors installed with a multiple TMD （MTMD） system considering human comfort is introduced, largely based on a study of existing literature. Finally, a design, analysis and field test is conducted using several large scale buildings in China including the Beijing Olympic Park National Conference Center, Changsha New Railway Station and the Xi＇an Northern Railway Station. The analytical and field test results show that the MTMD system designed using the proposed method is capable of effectively mitigating the vertical vibration of long-span floor structures. The study presented in this paper provides an important reference for the analysis of vibration serviceability of similar long-span floors and design of control system for these structures.
基金conducted as part of the research program of the Office of Mine Safety and Health Research of the National Institute for Occupational Safety and Health(NIOSH)
文摘A limestone mine in Ohio has had instability problems that have led to massive roof falls extending to the surface. This study focuses on the role that weak, moisture-sensitive floor has in the instability issues.Previous NIOSH research related to this subject did not include analysis for weak floor or weak bands and recommended that when such issues arise they should be investigated further using a more advanced analysis. Therefore, to further investigate the observed instability occurring on a large scale at the Ohio mine, FLAC3 D numerical models were employed to demonstrate the effect that a weak floor has on roof and pillar stability. This case study will provide important information to limestone mine operators regarding the impact of weak floor causing the potential for roof collapse, pillar failure, and subsequent subsidence of the ground surface.
文摘A floor heating system is a traditionary famous in Asian countries, especially in North East of China and Korea. In this report, we intended to clarify the effect of floor hating system for accessing a peripheral leukocyte regulation in winter season by evidence-based manner more than VAS. We set up two different office rooms heat-controlled by floor heating and air-conditioned by ceiling electric heater. Both qualitative and quantitative approaches determine which are better therapeutic effective recipes for this trial. The elements were evaluated by the total number of peripheral leukocyte, granulocyte and lymphocyte ratio and lymphocyte subsets. For 5 days of working in each conditioned room, the volunteers were changed the room after one-week interval for cooling down. Floor heating system regulated total number of peripheral leukocyte. The mode of the action for the high number of the volunteer was down-regulated. On the contrary, in lower numbers it was up-regulated after the trial. The number of leukocyte subsets, granulocyte and lymphocyte were also regulated by dose dependent manner. Emotional hormone, adrenalin, cortisone and nor-adrenaline were down regulated by floor heating but dopamine was up-regulated by this heating system. The reversal results were obtained by the group who worked in the conditioned room by the system heating from ceiling.
