Ergonomics in the hoeing operation

The hoeing operation is extensively required in farm tasks, such as seed-bed preparations, cutting root crops, etc. In seven male farmers (age: 27.4 ± 5.9 years), using two types of hoes (A&B), the physiological and biomechanical strains were evaluated, and hoeing speeds in low lift (LL) and high lift (HL) work were optimized. The heart rates (161–176 beats/min) and VO₂ demands (71–89% VO_2max) indicated extremely heavy work loads. Hoe A (blade-handle angle: 65°) was less strenuous in LL, while Hoe B (blade-handle angle: 87°) was better in HL work. During the hoeing sequence, the torque and compressive forces at the L5-S1 disc increased with the trunk inclination, up to about 65°; beyond 55° inclination, the torque at the L5-S1 disc exceeded the upper limit (135 Nm) allowed for a day's work. The work output was optimized equating at 50% VO_2max, i.e, stroke rate: 53 and 21 strokes/min; weight of soil dug: 123 and 54 kg/min, and area of soil dug: 1.34 and 0.33 sq.m./min in LL and HL work respectively. In general, farmers are suggested to adopt the LL mode of hoeing; with a 10 min work to 7 min rest ratio, the 8 h work output was derived as 400 to 450 sq.m. A hoe, weighing about 2 kg, having blade-handle angle 65 to 70°, blade length 25 to 30 cm, blade width 22 to 24 cm, handle length 70 to 75 cm, and the handle diameter 3 to 4 cm may be suitable for different modes of hoeing.     

Ergonomics of a large interactive graphics operation

Interactive computer graphics is one of the most dynamic examples of a man-machine environment. In contrast to many man-machine environments, the primary element in the interactive graphics process is analysis and the secondary element is physical reaction. Frustration and fatigue are the major factors which describes the human factors that were considered in establishing the physical environment of a large-production interactive graphics operation for the computer-aided design of printed circuit boards for Bell Telephone System products.     

Ergonomics in schools

This Special Issue on Ergonomics in Schools is dedicated to the memory of my co-guest editor Cheryl Bennett who sadly and unexpectedly passed away peacefully on 2 July 2007 - only 10 days before this editorial was completed. Cheryl was inspirational in her vigorous championing of this new area of ergonomics activity, most prominently and to great effect through her foundation chairmanship of the International Ergonomics Association (IEA) Technical Committee on Ergonomics for Children in Educational Environments (ECEE) (see www.iea.cc).     

Ergonomics in Hungary

This report was made possible by a grant from the National Academy of Sciences. The NAS maintains an exchange programme with the USSR and Eastern European countries in order to stimulate the development of improved scientific relationships between East and West. The author participated in this exchange programme as an individual researcher and not as a representative of his employer, The Lockheed Missiles and Space Co.     

Ergonomics in Systems Design

The relationship between ergonomics and systems design is defined and its importance is stressed. The origins of systems ergonomics are described and it is suggested that the technology of ergonomics now depends primarily on the science of psychology with some importance still attached to anatomy but with physiology now of marginal relevance. The differences in approach and objectives between systems ergonomics and classical ergonomics are summarized and, although it is admitted that our expertise in these fields is not adequate for our practical responsibilities, it is concluded that the progress of science and technology in both engineering and human factors are now inter- and cross-dependent.     

Ergonomics practice in manufacturing

To improve the practice of ergonomics, particularly its implementation in manufacturing, the mission of the discipline itself must be examined with respect to the mission of manufacturing industry. Examples of theoretical foundations of ergonomics show a consistent response to practical demands. The environment in which ergonomics operates, in this case manufacturing, is also responding to changed demands. Global competition is forcing industries to be concerned with both their strategic plans and the detailed implementation of continuous improvement. Both concerns have strong implications for how ergonomics practice is conducted. Examples of successful ergonomics implementation in this changing environment suggest that the profession should consider operating at a more strategic level if it wishes to achieve detailed changes at a lower level.     

登山鞋中的人机工程学

鞋是人类文明进步的标志性产物,它为人类的生存与发展提供了关键性的帮助。在远古时期,人类会用树叶、树皮、野草等来充当足部的临时保护层,直至今日人类不断地发掘新材料和技术,以至于我们发明了迄今为止最为符合人体机能的鞋子。文章将从鞋的人机工程方面入手来分析登山鞋与人之间的关系。     

Ergonomics International

It was the purpose of this study to examine whether replacing long pants (P) with shorts (S) would reduce the heat stress of wearing firefighting protective clothing during exercise in a warm environment. Twenty-four Toronto Firefighters were allocated to one of four groups that performed heavy (H, 4.8?km·h^?1, 5% grade), moderate (M, 4.5?km·h^?1, 2.5% grade), light (L, 4.5?km·h^?1) or very light (VL, 2.5?km·h^?1) exercise while wearing their full protective ensemble and self-contained breathing apparatus. Participants performed a familiarization trial followed by two experimental trials at 35°C and 50% relative humidity wearing either P or S under their protective overpants. Replacing P with S had no impact on the rectal temperature (T_re) or heart rate response during heavy or moderate exercise where exposure times were less than 1?h (40.8?±?5.8 and 53.5?±?9.2?min for H and M, respectively while wearing P, and 43.5?±?5.3 and 54.2?±?8.4?min, respectively while wearing S). In contrast, as exposure times were extended during lighter exercise T_re was reduced by as much as 0.4°C after 80?min of exercise while wearing S. Exposure times were significantly increased from 65.8?±?9.6 and 83.5?±?11.6?min during?L and VL, respectively while wearing P to 73.3?±?8.4 and 97.0?±?12.5?min, respectively while wearing S. It was concluded that replacing P with S under the firefighting protective clothing reduced the heat stress associated with wearing the protective ensemble and extended exposure times approximately 10?–?15% during light exercise. However, during heavier exercise where exposure times were less than 1?h replacing P with S was of little benefit.