Audio lectures can be downloaded from www.iitk.ac.in/che/nv.html

ChE Triad Lecture Series materials were prepared during the pandemic when faculty were quarantined at home, and classes were held in online mode. It was a unique and first-hand experience for me to deliver online lectures. The online lectures ran for almost three academic years or six semesters. During that period, we also uploaded lecture materials at the e-server of the institute, which students could access. As an instructor, I taught Transport Phenomena, Finite Differencebased Numerical Methods, and Heterogeneous Chemical Reaction Engineering at the graduate level. The lecture materials that I prepared during the online classes have culminated in ChE Triad Lecture Series. Most of the Indian as well as foreign universities consider these three courses to be compulsory for graduate students. I hope that this lecture series shaped in a book are useful to readers, but I must caution students that they should not wholly depend on the materials covered in the book. Rather, they should refer the standard text books prescribed by their course instructors in regular offline classes. I have my opinion that a comprehensive understanding of the topics is possible only through the offline lectures. Thus, I have a plan to develop audio lectures in the near future, which will be instructive and recorded in sync with the present e-lectures. To this end, this effort is painfully dedicated to all Covid warriors who risked their health and life in serving people during the pandemic, while we enjoyed delivering online lectures at home.