The 10 odd years that I spent in the Banaras Hindu University campus are deeply etched in my memory. For now I will leave most of it out and dwell on the years spent in the compelling presence of our Guruji- Prof. O. N. Srivastava. 

I was enrolled as a PhD scholar with (Late) Dr. A.K.Singh and Guruji was my co-guide.  Hence my interaction for first couple of years was with Ajay Sir and then when he left for a long term sabbatical to the US, I sought guidance from Guruji. In a nutshell, my situation was a bit unique. In the absence of a good email connection in the 90s, I had sporadic discussions with Ajay Sir and worked closely with Guruji during the next couple of years. The broad topic of my PhD work was the newly discovered carbon nanotubes and fullerenes and the characterisation tool was mainly electron microscopy and Guruji would keep me focused on the recent literature on the subject. Though, I never learnt to use the electron microscope until 2001, at my post-doctoral tenure in Germany, he ensured that I was thorough with the theoretical aspects of the subject and suggested that I read up the details from a book authored by P.B. Hirsch. Every once a while he would check my progress on the vast subject of electron microscopy.

Since this was the first time the topic (carbon nanotubes) was being researched in the group, he made it a point to direct a few questions my way in our tea-club sessions. I recall, I was initially, rather nervous about fielding the questions but soon discovered that these were the best opportunities to discuss and get his nod on the next steps in the experiments, sort out instrument-related or material procurement issues. Research took its time and all my papers were on the electron microscopy of unique carbon and silicon nano- structures. On one such occasion Guruji joined Ajay Sir at the microscope to study the in-situ transformations of fullerenes by e- beam annealing to nanotubes, whiskers and diamond- like carbon. This was quite a curious finding and would be followed by several discussions to understand the allotropic transformations The moment was again recounted when I met Sir Harry Kroto (one of three Nobel Prize winners in Chemistry for the discovery of fullerenes), in his labs at Sussex, UK. In my current job with a petrochemical company, I work extensively at the TEMs and while working alone in the dark room, am inadvertently, transported to my PhD days where the first lessons of the TEM were learnt.

Like all his students, It is with fondness that I recall the endless ‘kulhads’ (clay cups) of hot chai, with samosas or laddoos in the tea-club sessions and looking back, perhaps, the hour of the day when Guruji relaxed with his team. Apart from scientific discussions he used to talk to the other technical staff, checking about their jobs and well-being. Once a while, he would veer off these scientific discussions to talk about some political situation or news clipping, giving us a rare glimpse of his wry sense of humour.

I left for Germany in the year 2000, and my interactions with Guruji, though limited, continued over emails, mostly to share my thoughts on carbon nanotubes based polymer or ceramic composites. If memory serves me right, my last interaction with him was in the year 2002, when I visited the Physics Department and had the opportunity of a long discussion with him in his office. Needless to say that this was a rare event. We talked about my research at the Max Planck Institute, Stuttgart, my career aspirations, future plans and the ongoing research projects in the lab amongst other things. I recall leaving his office with a sense of fulfilment and also of wonderment at his continued enthusiasm in vast spectrum  of research topics. The PhD journey was at times arduous and lonely but every bit worth it!

At this juncture, I must iterate, that I was doubly blessed to be mentored by both Guruji and Ajay Sir. Both their styles were starkly different and yet the learning from them were the same- to work with passion and honesty.  The knowledge and learning, I believe, is a gift from them to me, to treasure, imbibe and emulate.