Batch processes are usually involved with multiple phases in the time domain and many researches on process monitoring as well as quality prediction have been done using phase information. However, few of them conside...Batch processes are usually involved with multiple phases in the time domain and many researches on process monitoring as well as quality prediction have been done using phase information. However, few of them consider phase transitions, though they exit widely in batch processes and have non-ignorable impacts on product qualities. In the present work, a phase-based partial least squares (PLS) method utilizing transition information is proposed to give both online and offline quality predictions. First, batch processes are divided into several phases using regression parameters other than prior process knowledge. Then both steady phases and transitions which have great influences on qualities are identified as critical-to-quality phases using statistical methods. Finally, based on the analysis of different characteristics of transitions and steady phases, an integrated algorithm is developed for quality prediction. The application to an injection molding process shows the effectiveness of the proposed algorithm in comparison with the traditional MPLS method and the phase-based PLS method.展开更多
This paper attempts to identify the loss of quality of craftsmanship intensive products. It shows that errors in production process and degradation in the jewellery pro duct quality in the (complex) transition from...This paper attempts to identify the loss of quality of craftsmanship intensive products. It shows that errors in production process and degradation in the jewellery pro duct quality in the (complex) transition from hand crafted silver model making to mass production are largely due to the ignorance of the importance of design——craftsmanship in production process. In fact, the design can be employed to solve the problems of the quality degradation or even as a tool to prevent error in the stages of product design, development and production. In testing this hypo thesis, production processes (from designing, model making, casting, polishing, buffing to texturing) are all examined in order to identify the root causes of product quality degradation in mass production. After the analysis, the concept of “integrated craftsmanship” is proposed to assist integration of traditional goldsmith′s and je wellery designers′ techniques in jewellery designing and making, and to change the attitudes to quality control in mass production systems. Finally, the model of “integra ted design craftsmanship” as a comprehensive design conceptual and quality organizational tool is formulated for managing and improving product quality.展开更多
The results of commercial application of two types of C_8 aromatics isomerization catalysts under different feed conditions were compared to gain an insight in the techno-economical basis for selecting proper technolo...The results of commercial application of two types of C_8 aromatics isomerization catalysts under different feed conditions were compared to gain an insight in the techno-economical basis for selecting proper technological route at the plant.The comparison reveals differences in every aspect of feed consumption,unit capacity,product output,product distribution,and unit process parameters depending upon which catalyst type is adopted by the integrated PX complex.The type of aromatics isomerization catalyst has its influence on the plant scale,the construction cost,the process unit capacity and the product cost,with the magnitude of its impact varying with changing feed conditions.展开更多
基金Supported by Guangzhou Nansha District Bureau of Economy & Trade, Science & Technology, Information, Project (201103003)the Fundamental Research Funds for the Central Universities (2012QNA5012)+1 种基金Project of Education Department of Zhejiang Province (Y201223159)Technology Foundation for Selected Overseas Chinese Scholar of Zhejiang Province (J20120561)
文摘Batch processes are usually involved with multiple phases in the time domain and many researches on process monitoring as well as quality prediction have been done using phase information. However, few of them consider phase transitions, though they exit widely in batch processes and have non-ignorable impacts on product qualities. In the present work, a phase-based partial least squares (PLS) method utilizing transition information is proposed to give both online and offline quality predictions. First, batch processes are divided into several phases using regression parameters other than prior process knowledge. Then both steady phases and transitions which have great influences on qualities are identified as critical-to-quality phases using statistical methods. Finally, based on the analysis of different characteristics of transitions and steady phases, an integrated algorithm is developed for quality prediction. The application to an injection molding process shows the effectiveness of the proposed algorithm in comparison with the traditional MPLS method and the phase-based PLS method.
文摘This paper attempts to identify the loss of quality of craftsmanship intensive products. It shows that errors in production process and degradation in the jewellery pro duct quality in the (complex) transition from hand crafted silver model making to mass production are largely due to the ignorance of the importance of design——craftsmanship in production process. In fact, the design can be employed to solve the problems of the quality degradation or even as a tool to prevent error in the stages of product design, development and production. In testing this hypo thesis, production processes (from designing, model making, casting, polishing, buffing to texturing) are all examined in order to identify the root causes of product quality degradation in mass production. After the analysis, the concept of “integrated craftsmanship” is proposed to assist integration of traditional goldsmith′s and je wellery designers′ techniques in jewellery designing and making, and to change the attitudes to quality control in mass production systems. Finally, the model of “integra ted design craftsmanship” as a comprehensive design conceptual and quality organizational tool is formulated for managing and improving product quality.
文摘The results of commercial application of two types of C_8 aromatics isomerization catalysts under different feed conditions were compared to gain an insight in the techno-economical basis for selecting proper technological route at the plant.The comparison reveals differences in every aspect of feed consumption,unit capacity,product output,product distribution,and unit process parameters depending upon which catalyst type is adopted by the integrated PX complex.The type of aromatics isomerization catalyst has its influence on the plant scale,the construction cost,the process unit capacity and the product cost,with the magnitude of its impact varying with changing feed conditions.
