Design,Manufacture and Maintenance of Pressure Equipment Based on Accidents Survey

Most of the important units of pressure equipment have been manufactured successfully in China related to the national key construction projects,such as 10 million tons/year oil refinery,million tons/year ethylene,large coal chemical,etc.However,some of them failed to operate shortly after their putting into service.Some suffered severe damage even during the previous period of manufacture and installation.In this paper,cases of accident survey and failure analysis are given for some typical pressure vessels.It is found that many accidents are related to insufficient consideration of the design and manufacture of the equipment.These accidents occur fundamentally because of the Chinese design standards codes for pressure equipment without risk or life concepts and the support from a database for potential risk existing in their dynamic service.Most designers and manufacturers are unable to make correct design,materials selection and manufacturing process all due to a lack of engineering experience.In order to avoid the repetition of the accidents and improve the safety,reliability and economy of pressure equipment,a platform is suggested for design,manufacture and maintenance of pressure equipment in China based on accidents survey.In other words,some effective precautionary measures are taken at the design and manufacture stage,and the design methodology has to be based on service life requirement and desirable risk level.At the service stage some reasonable inspection/monitoring approaches should be utilized to control risks and ensure the equipment operating safely until its desired lifespan.Finally,the basic scheme and some key technologies are briefly given for the platform construction.The concept of risk and life based design,manufacture and maintenance proposed herein has important significance for improving and perfecting the codes and standards for design,manufacture and maintenance of Chinese pressure-bearing equipment,enhancing the life and reliability of Chinese pressure-bearing equipment and promoting the development of in-service maintenance technology that combines safety and economy.

A convenient synthesis of quinazoline derivatives via cascade imino-Diels-Alder and oxidation reaction

Quinazoline derivatives were synthesized fromα-iminoesters via a cascade imino-Diels-Alder and then oxidation reaction catalyzed with CuBr_2.This method provided a new strategy for preparing quinazoline derivatives which may be useful in the synthesis of heterocyclic intermediates.

Chitosan based antibacterial composite materials for leather industry: a review

Chitosan is an amorphous translucent substance with a structural unit similar to the polysaccharide structure of the extracellular matrix,It has good antibacterial,biocompatible,and degradable properties.It has important application value in leather,water treatment,medicine,food and other fields,so chitosan and its modified products have received widespread attention.This article reviewed the preparation methods of chitosan-based antibacterial composites in recent years,including chitosan/collagen,chitosan/graphene,chitosan/tannic acid,and chitosan/polyethylene glycol composite materials,elaborates their modification methods and antibacterial mechanism were reviewed in detail,and its applications in the leather industry as antibacterial auxiliaries and water treatment antibacterial adsorption materials were discussed.Finally,the future development and challenges of chitosan-based composite materials in the leather industry were forecasted.