Mining Engineering                    Engineering Science and Mechanics

I graduated with Master of Engineering degree in Mining Engineering from the Department of Energy & GeoEnvironmental Engineering in December 2001. I wrote a comprehensive paper on "Kaiser effect studies in rocks" for the degree fulfillment. My graduate advisor was Dr. Reginald Hardy. I also developed a Finite Element model to study the stress and strain distributions in an end-capped rock specimen under compression. This work was done as a part of an independent study. I hope to publish the results soon.

Abstract of the paper [PDF File Kaiser effect studies in rock]

There have been many attempts by various researchers to utilize the Kaiser effect to determine in-situ stress in rocks. A thorough and foolproof technique would mean reduction in cost of in-situ stress determination as well as reduction of loss of material underground due to conservative safety factors. This paper details the origin and the development and refinement of the Kaiser effect technique for determining in-situ stress in geologic structures. Since the analytical methods used to evaluate the Kaiser stress from the experimental data have an important bearing on the determined stress values, the available analytical procedures have been dealt in detail. Literature shows that there exist two schools of thought in interpreting the Kaiser stress determined. The determined Kaiser stress might indicate the previous maximum stress or the current prevailing stress in the geologic structure. The literature available on both of these ideas has been presented in this paper. It is the author's opinion that the Kaiser stress indicates the previous maximum stress and it is with this conclusion, the entire Kaiser effect studies have been conducted. Though many researchers have attempted to use the Kaiser effect for in-situ stress determination, the data they obtained is not very consistent with the fundamental principles of physics and mechanics. So, this paper attempts to put together the works of researchers on the theoretical principles behind the concept of the Kaiser effect. Since crack propagation is supposed to be the primary reason for the enormous acoustic emission (AE) generated during the loading of a rock specimen, the theory of crack propagation has been dealt with in some detail. The opinion of researchers regarding whether the Kaiser effect can be utilized for determining in-situ stress in rocks has also been discussed. The author had conducted tests to determine the pre-load stress in rock specimens using the Kaiser effect technique. The experimental procedure involved in these tests has been described in detail, starting from the preparation of specimens, pre-stressing of master specimens., coring of smaller specimens, end-capping of smaller specimens to the arrangements for the uniaxial reloading and acoustic emission data acquisition. It is the feeling of the author that uniaxial reloading of a triaxially pre-stressed rock specimen should depict the stress history because the AE onset stress is a function of all the three principal stresses that were acting on the rock.

 

  

I started work at the Engineering Nano-Characterization center with Dr. Bernhard Tittmann in 2000. I am expecting to graduate early 2005. I got interested in Non-destructive evaluation when I took a course in it, offered by Dr. Tittmann.


To begin with, I worked on a project sponsored by Loomis Inc., dealing with dicing wafers and the diamond tip wear using Acoustic Emission and Microscopic Techniques. It was proprietary work and therefore, I am not discussing the results here.

My Ph.D. research is focused on the use of acoustic spin resonance techniques for material characterization. This work is sponsored by the Lawrence Livermore National labs. Dr. Pat Lenahan is the Co-P.I. of the project. Dr. Peter Shull (Penn State Altoona), Georgios Maillis and Laura Stimely (undergraduates) are also involved with the project.

I am also currently involved in a project investigating the effects of mechanical impact on living cells. The various modes of impacts include application of high intensity ultrasound, Laser pulses and blunt impact from a pellet.

I also worked on a project that involved the characterization of the quality of food products using non-contact ultrasound. some results.

Other projects I have dabbled with are:

  • Feasibility of healing damage in a AS4/PEEK composite plate

  • Electronic speckle pattern interferometry for monitoring thermal strains in ceramics

  • Electro-magnetic acoustic transmitters for non-destructive evaluation of locomotive wheels

  • Non-contact ultrasonic characterization of elastomers

PowerPoint Presentations:

1. NAR literature (A) and (B)

2. NAR Project Review

3. SPIE 2004 Presentations

 

List of Publications

Giving credit where it is due

While I am here, I have to thank all my teachers all the way to date who shaped me in to what I am. My math teachers, Ms.Padmavathi (9th and 10th grade) and Mr.Santhanam (11th and 12th grade), Thanks a lot. I am so grateful to my Senior thesis advisor, Dr.D.P.Singh (who then, was the Dept of Mining, IT-BHU chair as well), who really gave me the nudge and the then IT-BHU director, Dr.Bhattacharya, who made me realize that, after all, teaching can also be very much fun. Dr.Hardy and Dr.Tittmann, Thank you so very much.