A model of grade transition is presented for a commercialized fluidized bed gas-phase polyethylene production process. The quantity of off-specification product and the time of grade transition can be minimized by the...A model of grade transition is presented for a commercialized fluidized bed gas-phase polyethylene production process. The quantity of off-specification product and the time of grade transition can be minimized by the optimization of operating variables, such as polymerization temperature, the ratio of hydrogen to ethylene, the ratio of co-monomer to ethylene, feed rate of catalyst, and bed level. A new performance index, the ratio of melt flow (MFR), is included in the objective function, for restraining the sharp adjustment of operation variables and narrowing the distribution of molecular weight of the resin. It is recommended that catalyst feed rate and bed level are decreased in order to reduce the grade transition time and the quantity of off-specification product. This optimization problem is solved by an algorithm of sequential quadratic programming (SQP) in MATLAB. There is considerable difference between the forward transition and reverse transition of grade with regard to the operating variables due to the non-linearity of the system. The grade transition model is extended to a high space time yield (STY) process with the so-called condensed model operation. In the end, an optimization strategy for multi-product transition is proposed with two-level optimization of the objective function J(x,u) on the basis of the optimal grade transition model. A sequential transition of six commercial polyethylene grades is illustrated for an optimal multi-product operation.展开更多
This study investigates the language strategies used by Shakespeare in The Tragedy of Hamlet, Prince of Denmark （1603）. Emphasis is given to the type of language or register Shakespeare provides his characters with ...This study investigates the language strategies used by Shakespeare in The Tragedy of Hamlet, Prince of Denmark （1603）. Emphasis is given to the type of language or register Shakespeare provides his characters with in order to give them genuine or assumed identities. The linguistic register of the three major characters of Claudius, the Ghost, and Hamlet is explored in light of the Elizabethan cultural context. This concern with these three characters stems from the basic assumption of the paper that the play is a struggle between Claudius and the Ghost over Hamlet. Claudius speaks the language of a monarch which is informed by the code of society; the Ghost, who used to speak such language of sovereignty while alive, speaks a language of the dead informed by a newly acquired experience not familiar to human beings. On the other hand, Hamlet＇s use of language is the most peculiar in the play. His register keeps changing according to his tragic growth and his readiness for action. The study indicates that the language functions Shakespeare utilizes in Hamlet are numerous. Language is used creatively for a variety of purposes in addition to communication. The playwright employs language as a shield for self-defense, a tool for defining and hiding identity and misleading and manipulating others, a means of search for reality, and a tool for punishment, among other functions. The study findings invite further research into Shakespeare＇s use of language in his plays. No detailed in-depth studies of Shakespearean language and its implications exist.展开更多
Industrial cluster is an aggregation of the related enterprises and institutions in certain field and in certain place. There are mainly three patterns for industrial clusters： market-oriented cluster, foreign fund o...Industrial cluster is an aggregation of the related enterprises and institutions in certain field and in certain place. There are mainly three patterns for industrial clusters： market-oriented cluster, foreign fund oriented cluster and endogenous brand oriented cluster. Many economists have established their own theories about the patterns industrial cluster, but there are few dealing with one big enterprises and its cluster pattern. This paper, taking Haier household electrical appliance as an example, is trying to study one model of Chinese industrial cluster and analyze its characteristics with their effects on economy, as.well as the advantages together with the related suggestions from the authors.展开更多
For companies“going global,”diff erences in culture and working habits are often the biggest hindrance.But CRRC Yongji Electric believes the essence of its success in the Indian market lies in communication and mutu...For companies“going global,”diff erences in culture and working habits are often the biggest hindrance.But CRRC Yongji Electric believes the essence of its success in the Indian market lies in communication and mutual understanding.展开更多
In this paper, design and fabrication of a commemorative plaque are described and presented. The plaque was fabricated to honour the memory of the 14 women massacred at L＇Ecole Polytechnique in Montreal. This plaque ...In this paper, design and fabrication of a commemorative plaque are described and presented. The plaque was fabricated to honour the memory of the 14 women massacred at L＇Ecole Polytechnique in Montreal. This plaque is the result of a project partnership between the Faculties of Engineering and Fine Arts, and was sponsored by the Office of the Vice-President Academic and Provost. An art design was selected through a contest coordinated by the Visual Arts Departmment. The selected art design was then turned over to the Mechanical Engineering Department to be converted to a 3-dimensional （3D） solid model and then eventually fabricated on a computer numerical control （CNC） milling machine. The fabricated plaque was unveiled during the December 2010 Memorial event at UVic.展开更多
文摘A model of grade transition is presented for a commercialized fluidized bed gas-phase polyethylene production process. The quantity of off-specification product and the time of grade transition can be minimized by the optimization of operating variables, such as polymerization temperature, the ratio of hydrogen to ethylene, the ratio of co-monomer to ethylene, feed rate of catalyst, and bed level. A new performance index, the ratio of melt flow (MFR), is included in the objective function, for restraining the sharp adjustment of operation variables and narrowing the distribution of molecular weight of the resin. It is recommended that catalyst feed rate and bed level are decreased in order to reduce the grade transition time and the quantity of off-specification product. This optimization problem is solved by an algorithm of sequential quadratic programming (SQP) in MATLAB. There is considerable difference between the forward transition and reverse transition of grade with regard to the operating variables due to the non-linearity of the system. The grade transition model is extended to a high space time yield (STY) process with the so-called condensed model operation. In the end, an optimization strategy for multi-product transition is proposed with two-level optimization of the objective function J(x,u) on the basis of the optimal grade transition model. A sequential transition of six commercial polyethylene grades is illustrated for an optimal multi-product operation.
文摘This study investigates the language strategies used by Shakespeare in The Tragedy of Hamlet, Prince of Denmark （1603）. Emphasis is given to the type of language or register Shakespeare provides his characters with in order to give them genuine or assumed identities. The linguistic register of the three major characters of Claudius, the Ghost, and Hamlet is explored in light of the Elizabethan cultural context. This concern with these three characters stems from the basic assumption of the paper that the play is a struggle between Claudius and the Ghost over Hamlet. Claudius speaks the language of a monarch which is informed by the code of society; the Ghost, who used to speak such language of sovereignty while alive, speaks a language of the dead informed by a newly acquired experience not familiar to human beings. On the other hand, Hamlet＇s use of language is the most peculiar in the play. His register keeps changing according to his tragic growth and his readiness for action. The study indicates that the language functions Shakespeare utilizes in Hamlet are numerous. Language is used creatively for a variety of purposes in addition to communication. The playwright employs language as a shield for self-defense, a tool for defining and hiding identity and misleading and manipulating others, a means of search for reality, and a tool for punishment, among other functions. The study findings invite further research into Shakespeare＇s use of language in his plays. No detailed in-depth studies of Shakespearean language and its implications exist.
文摘Industrial cluster is an aggregation of the related enterprises and institutions in certain field and in certain place. There are mainly three patterns for industrial clusters： market-oriented cluster, foreign fund oriented cluster and endogenous brand oriented cluster. Many economists have established their own theories about the patterns industrial cluster, but there are few dealing with one big enterprises and its cluster pattern. This paper, taking Haier household electrical appliance as an example, is trying to study one model of Chinese industrial cluster and analyze its characteristics with their effects on economy, as.well as the advantages together with the related suggestions from the authors.
文摘For companies“going global,”diff erences in culture and working habits are often the biggest hindrance.But CRRC Yongji Electric believes the essence of its success in the Indian market lies in communication and mutual understanding.
文摘In this paper, design and fabrication of a commemorative plaque are described and presented. The plaque was fabricated to honour the memory of the 14 women massacred at L＇Ecole Polytechnique in Montreal. This plaque is the result of a project partnership between the Faculties of Engineering and Fine Arts, and was sponsored by the Office of the Vice-President Academic and Provost. An art design was selected through a contest coordinated by the Visual Arts Departmment. The selected art design was then turned over to the Mechanical Engineering Department to be converted to a 3-dimensional （3D） solid model and then eventually fabricated on a computer numerical control （CNC） milling machine. The fabricated plaque was unveiled during the December 2010 Memorial event at UVic.
