Complex industrial systems, including mining, have a prominent challenge in understanding the interrelationship among the cognitive processes, working environment and available equipment. The concept of cognitive work...Complex industrial systems, including mining, have a prominent challenge in understanding the interrelationship among the cognitive processes, working environment and available equipment. The concept of cognitive work analysis(CWA) transcends the traditional analytic methods of evaluating human tasks solely based on perceptual and physical traits, and rather implements the notions of behavioral and cognitive awareness indispensable for the intricacy of modern technology. In the last few decades, academic and industrial settings employ this type of analysis to set a suitable standard for a system's safety feasibility, and as a result reduce human-based errors. This research paper analyzes current CWA methods and proposes a five-level quantification model portraying the overall cognitive quality of a mining operation.展开更多
An appropriate coupled cohesive law for predicting the mixed mode failure is established by combining normal separation and tangential separation of surfaces in the cohesive zone model （CZM） and the cohesive element...An appropriate coupled cohesive law for predicting the mixed mode failure is established by combining normal separation and tangential separation of surfaces in the cohesive zone model （CZM） and the cohesive element method. The Xu-Needleman exponential cohesive law with the fully shear failure mechanism is one of the most popular models. Based on the proposed consistently coupled rule/principle, the Xu-Needleman law with the fully shear failure mechanism is proved to be a non-consistently coupled cohesive law by analyzing the surface separation work. It is shown that the Xu-Needleman law is only valid in the mixed mode fracture when the normal separation work equals the tangential separation work. Based on the consistently coupled principle and the modification of the Xu-Needleman law, a consistently coupled cohesive （CCC） law is given. It is shown that the proposed CCC law has already overcome the non-consistency defect of the Xu-Needleman law with great promise in mixed mode analyses.展开更多
The design with intent(DwI)toolkit assists designers in creating novel designs and interfaces.DwI,however,is not constrained to any degree,making it impossible to know whether the produced designs adequately account f...The design with intent(DwI)toolkit assists designers in creating novel designs and interfaces.DwI,however,is not constrained to any degree,making it impossible to know whether the produced designs adequately account for users’needs.In contrast,cognitive work analysis(CWA)is a human factors research tool that seeks to map a system and account for users’needs,yet does not provide clear guidelines for progressing such analysis into workable designs with which users can interact.This paper seeks to present a proof-of-concept investigation to demonstrate that DwI can be suitably constrained and validated by insights gained from CWA.CWA,in turn,benefits by having a suitable toolkit for progressing insights.Two teams of individuals without design backgrounds were able to develop mock-up in-vehicle interfaces aimed at reducing fuel use.The teams were able to use DwI toolkit to articulate the genesis of their ideas,which in turn could be directly linked to system needs identified within CWA.展开更多
In order to improve the mechanical properties of powder metallurgy （P/M） ferrite-pearlite steel, a dual phase （DP） ferrite-martensite steel was produced through intercritical annealing of sintered P/M preforms. Mi...In order to improve the mechanical properties of powder metallurgy （P/M） ferrite-pearlite steel, a dual phase （DP） ferrite-martensite steel was produced through intercritical annealing of sintered P/M preforms. Mi-crostructures of the sintered and DP steels were examined with optical, scanning and transmission electron microscopes. Mechanical properties were evaluated through hardness measurements and compression tests. Microstructural studies revealed that sintered steel contained polygonal ferrite-pearlite while the DP steel contained polygonal, lath and acicular ferrite along with lath-type martensite as microstructural constituents. In DP steels, with increasing mean preform density, the microstructure contained fine and continuous network of martensite colonies with minimum porosity. The work hardening rate vs plastic strain plots （Jaoul-Crussard analysis） of both the steels revealed typical three stage deformation behaviour for low and high mean preform densities. Compression tests revealed that, DP P/M steel displayed higher strength-plasticity combination than the sintered steel.展开更多
文摘Complex industrial systems, including mining, have a prominent challenge in understanding the interrelationship among the cognitive processes, working environment and available equipment. The concept of cognitive work analysis(CWA) transcends the traditional analytic methods of evaluating human tasks solely based on perceptual and physical traits, and rather implements the notions of behavioral and cognitive awareness indispensable for the intricacy of modern technology. In the last few decades, academic and industrial settings employ this type of analysis to set a suitable standard for a system's safety feasibility, and as a result reduce human-based errors. This research paper analyzes current CWA methods and proposes a five-level quantification model portraying the overall cognitive quality of a mining operation.
基金Project supported by the National Natural Science Foundation of China(Nos.50878117 and 51038006)the China Scholarship Council Project(No.M.H.HE-2009621076)the Tsinghua University Initiative Scientific Research Program(No.20101081766)
文摘An appropriate coupled cohesive law for predicting the mixed mode failure is established by combining normal separation and tangential separation of surfaces in the cohesive zone model （CZM） and the cohesive element method. The Xu-Needleman exponential cohesive law with the fully shear failure mechanism is one of the most popular models. Based on the proposed consistently coupled rule/principle, the Xu-Needleman law with the fully shear failure mechanism is proved to be a non-consistently coupled cohesive law by analyzing the surface separation work. It is shown that the Xu-Needleman law is only valid in the mixed mode fracture when the normal separation work equals the tangential separation work. Based on the consistently coupled principle and the modification of the Xu-Needleman law, a consistently coupled cohesive （CCC） law is given. It is shown that the proposed CCC law has already overcome the non-consistency defect of the Xu-Needleman law with great promise in mixed mode analyses.
基金funded by the UK Engineering and Physical Sciences Research Council(EPSRC)Grant EP/N022262/1“Green Adaptive Control for Future Interconnected Vehicles”(www.gactiv e.uk).
文摘The design with intent(DwI)toolkit assists designers in creating novel designs and interfaces.DwI,however,is not constrained to any degree,making it impossible to know whether the produced designs adequately account for users’needs.In contrast,cognitive work analysis(CWA)is a human factors research tool that seeks to map a system and account for users’needs,yet does not provide clear guidelines for progressing such analysis into workable designs with which users can interact.This paper seeks to present a proof-of-concept investigation to demonstrate that DwI can be suitably constrained and validated by insights gained from CWA.CWA,in turn,benefits by having a suitable toolkit for progressing insights.Two teams of individuals without design backgrounds were able to develop mock-up in-vehicle interfaces aimed at reducing fuel use.The teams were able to use DwI toolkit to articulate the genesis of their ideas,which in turn could be directly linked to system needs identified within CWA.
文摘In order to improve the mechanical properties of powder metallurgy （P/M） ferrite-pearlite steel, a dual phase （DP） ferrite-martensite steel was produced through intercritical annealing of sintered P/M preforms. Mi-crostructures of the sintered and DP steels were examined with optical, scanning and transmission electron microscopes. Mechanical properties were evaluated through hardness measurements and compression tests. Microstructural studies revealed that sintered steel contained polygonal ferrite-pearlite while the DP steel contained polygonal, lath and acicular ferrite along with lath-type martensite as microstructural constituents. In DP steels, with increasing mean preform density, the microstructure contained fine and continuous network of martensite colonies with minimum porosity. The work hardening rate vs plastic strain plots （Jaoul-Crussard analysis） of both the steels revealed typical three stage deformation behaviour for low and high mean preform densities. Compression tests revealed that, DP P/M steel displayed higher strength-plasticity combination than the sintered steel.
