大气污染过程中氮氧化合物对大气的危害及防治

针对在社会生产过程中排放的氮氧化物（NOx）对大气造成的污染情况,讨论了NOx的主要来源、生成机理及对人类生活的危害。并简要介绍了目前对NOx排放的控制处理技术,并简要阐述了经济发展和氮氧化物控制的相关联系。     

Investigation on strategies for optimizing process definition in rubber processing: A study on mechanical and chemical properties of vulcanizates as basis for the development of a new calculation model for quality prediction

Rubber compounds may exhibit significant batch variations due to multiple different ingredients mixed in one compound. Hence, defining the manufacturing process for constant part quality can be challenging. Common strategies in considering batch variations in rubber processing include the determination of reaction kinetics, and the definition of process parameters according to normalized vulcanization isotherms. Thereby, maintenance of the degree of cure is targeted. With this path, information on the mechanical properties of vulcanizates is lost, despite its visibility from the kinetic data and part quality assurance is missed. This contribution points out the differences obtained for parts produced to the same degree of cure at various temperatures and intends to emphasize new strategies in process definitions. Therefore, compression molded parts were produced from styrene-butadien rubber, which was then characterized with mechanical and chemical methods. Each of the methods revealed a significant difference in part behavior, which were manufactured to the same degrees of cure but at different temperatures. It was concluded that a temperature-dependent reaction rate should be considered when quality maintenance is targeted in the production. Only then will it be possible to predict the properties adequately, with simultaneous effect of enhancing sustainability policies in rubber processing.