Rabindra Nath Sen

Cardio-respiratory performance of porters carrying loads on a treadmill

Four workers, accustomed to load carrying, carried loads (no load, 60, 80 and 100 kg) at 0·89 and 1·03 m s−1 on a treadmill during the pre- and post-lunch period respectively, to obtain information regarding the degree of exhaustion from similar load carrying in their usual working situation. The rate of work is expressed in Watts. During pre- and post-lunch work there was a rise of 6 to 71 of pulmonary ventilation with each increment of 163 W. beyond the initial work level. The oxygen consumptions in the pre-lunch period were 15 to 27% higher, suggesting a greater anaerobic metabolism in the post-lunch period. The average work-pulse-rate varied from 116 to 162 beats min−. Cardiac demand for a particular load is more or less constant, irrespective of time of day. During the pre-lunch period the work-pulse-sum was 78, 71, 65 and 54 beats per 163 W for respective four loads;-where-as in the post-lunch period, except the initial load, it varied only between 56 to 60 beats per 163 W. indicating a proportionat...

Finite difference methods for certain singular two-point boundary value problems

The aim of this paper is to study the outcome of finite difference methods of mainly second order for the numerical solution of certain singular two-point boundary value problems. The method is mainly an extension of the method of Gustafsson (1973) from the linear to nonlinear differential equation and is particularly suitable when the differential equation in question cannot be reduced easily to an elegant system of first-order equations.

Ergonomics study of tea-leaf plucking operations: Criteria for selection and categorisation

This paper describes a new method for the categorisation of female tea-leaf pluckers on the basis of quantity and quality of production, skill and efficiency. Subjects participating in a study on the ergonomics of tea-leaf plucking operations were so categorised, and the results have been compared with the existing groupings followed by the Tea-estate authorities. Such a method could facilitate predictive selection of pluckers, selection for training, and formation of groups in future studies.

Tea-leaf plucking ― workloads and environmental studies

Abstract Heart rates and energy costs of female tea-leaf piuckers in India were studied while at rest, during walking (with and without basket loads) and during plucking. Walking with loaded baskets was the most strenuous job. The ‘fast’ category of pluckers had higher cardiac and gross energy costs than the ‘slow’ category. When the energy costs were linked to productivity, the ‘fast’ pluckers had lower costs per unit of productivity. The thermal load was found to be high, and the effectiveness of protective equipment such as indigenous hats has been discussed.

Ergonomic modifications of shovels in India

Submits that, in developing countries, there is still a large dependence on handheld, non‐mechanical tools. For a long time, the design of tools, such as shovels, has not improved. Describes a new design for a shovel, which reduces the workload and enhances productivity. The cost is minimal.