Sagar Sarkar

Laser Transformation Hardening of Steel

Abstract Laser surface hardening is a well-established process for enhancing the mechanical properties of selected surface areas of engineering parts made of different types of steel. Since this was first reported in the early seventies, much research has been done since to develop a deeper understanding of the process, process modeling for determining operating parameters, laser beam shaping, and online process monitoring. It still continues abated. In this paper, after presenting a brief description of the basic principle of laser hardening and the scientific work reported prior to the first decade of this century, the more recent research on its various aspects has been reviewed.

Selection of Alternate Work Systems to Improve Occupational Health of Indian Construction Workers: A Design of Experiment-Based Approach

From ergonomic point of view, work capability, efficiency, and performance of the workers may substantially decrease as they involve themselves in critical man-machine interactions during construction-related manual material handling tasks. Therefore, to improve the existing ergonomic performance of the work system as a whole with respect to a given MMH task, a number of alternatives are required to be developed to minimize latent risk factors and reduce their impact significantly on the performance of the workers, in relation to biomechanical or physiological parameters. In this chapter, a design of experiment-based comprehensive methodology is proposed and applied for a select critical MMH task with observations from a real construction site in India for identification of alternate work systems that are considered superior from biomechanical point of view through biomechanical assessment for calculating the reaction forces for a number of relevant joints and segments in human body, keeping occupational health of the workers as a major priority. The study may help to develop appropriate guidelines for workers which may reduce the occupational hazards and improve health, safety, and performance of workers under prevailing construction work environment in India.

Improving Occupational Health of Indian Construction Workers: A Biomechanical Evaluation Approach

An ergonomic study of manual material handling tasks in construction needs to address a number of manual material handling task-related problems such as pains in the back, shoulders and wrists, strain and sprain injuries, musculoskeletal disorders, severe fatigue and loss of energy of the workers and those acquired from improperly designed safety gadgets being used. Biomechanical modelling may help an analyst identify work system/manual material handling task-related factors and causes for such problems explicitly. In this paper, the details about the biomechanical modelling and analysis of a select manual material handling task at a construction site in India are presented. Based on a review of literature on available biomechanical modelling approaches, an appropriate biomechanical evaluation methodology is used for the select task. Results as obtained on the current status of occupational risk factors and musculoskeletal disorders among construction workers engaged in the task indicate the need for potential ergonomic performance improvement of critical construction jobs for which compressive force at L5/S1 disc and other joints is beyond their threshold values. The major findings from the study with observations from a real construction site match closely with the opinion of the workers and are indicative of the validity of biomechanical evaluation methodology as proposed.