Materials Design - Towards a Functionally Graded Electrical Conductor

In this study, we discuss functionally graded (FG) materials as pulsed electrical conductors. These conductors can be designed to be more efficient and longer lasting by applying numerical modeling tools. One focus is on limiting the thermal fatigue damage in conductors caused by very high temperatures that develop during pulse heating. We have quantified the effect of various grading functions on the pulsed Joule heating generated and the peak temperature experienced in the conductors of an electromagnetic launcher by using a 1D numerical code and a state of the art 3D coupled finite element code, EMAP3D. Because FG materials incorporate applications-tailored compositions, structures, and dimensions, smoothly graded properties in lateral and longitudinal cross sections are obtainable. The Solid Freeform Fabrication (SFF) processing approach allows for architectures with a series of important features. These features include the selective use of high efficiency conducting materials in the core, preconditioned conductor/structure interfaces, and built-in features for enhanced cooling where necessary.Mechanical Engineerin

Anthropometric considerations of farm tools/machinery design for tribal workers of northeastern India

Anthropometric body dimensions play a significant role in human-machine interaction.  The overall working efficiency of human-machine environment and resultant discomfort has severe impact while using farm tools and machinery in hills.  The northeastern region of India is predominantly hilly and inhabited by tribal population.  This study presents the anthropometric data of the agricultural workers of Meghalaya, which helps to develop/modify the tools and machinery suitable for the people of this Region.  In total 1027 subjects (566 male and 461 female) of five different tribes known as Khasi, Garo, Jaintia, Hajong and Koch from 35 different villages were selected randomly from seven districts.  Thirty-four body dimensions useful for agricultural equipment design were selected and measured.  The average weight of female workers was found to be about 10.1% lower than the male workers and the average stature of male was nearly 6.9% higher than the female. Similar trend was observed in most of the measured body dimension.  The collected data showed non-significant difference among various body dimensions while comparing with other northeastern states.  The efforts have been made to illustrate the application of anthropometric data in the design of farm equipments through some examples.Keywords: Anthropometry, farm machinery design, farm tools Citation: Agrawal K. N., R. K. P Singh, and K. K. Satapathy.  Anthropometric considerations of farm tools/machinery design for tribal workers of northeastern India.  Agric Eng Int: CIGR Journal, 2010, 12(1): 143-150. &nbsp

Effect of thresher drive linkage design on human physiological workload of a pedal operated thresher

Abstract: Pedal operated paddy threshers are widely used in the rice growing countries such as India, Bangladesh, Bhutan, Korea and some African countries.  Thresher-drive linkage plays a vital role in human-machine interaction and workload on the human operator.  The four-bar linkage design used in pedal operated paddy thresher was replaced with four alternative designs of thresher drive-linkages to assess the load application pattern and physiological work load while operating the pedal operated paddy thresher.  The machine was tested with five operators for physiological workload estimation.  The linkage combinations were found to have significant effects at 1% level on the work pulse rate and workload to operators.  Considering the force-displacement relationships and physiological workload on the operators, linkage three was found to be the most promising design with lowest work pulse rate of  45.90 beats min-1 and change in energy expenditure rate of 214.5 W (12.87 kJ min-1).   Keywords: pedal operated thresher, thresher, thresher drive linkage, physiological workloa