 AD stands for ANNO DOMINI which refers to Christ's birth. BC is before Christ. CE stands for 'Common Era' and is a recent term. It is used in place of AD.   BCD stand â¦ s for 'Before Common Day' and is used instead of BC, however it is more commonly represented as BCE, 'Before Common Era'.
Chemical engineers typically do the following: 1  Conduct research to develop new and improved manufacturing processes. 2  Develop safety procedures for those working with dangerous chemicals. 3  Develop processes for separating components of liquids and gases, or for generating electrical currents, by using controlled chemical processes.
A variety of industries employ chemical engineers, representing a diverse range of products, employers, and services. The focus of companies in this industry is on the development, extraction, isolation, combination, and use of chemicals and chemical by-products. Chemical engineers design and operate processes and systems to combine, transport, separate, handle, recycle, and store them.