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The effect of 3–25 Hz vibration on the legibility of numeric light emitting diode displays
12.3.29 (80203)
Hits, D.S. An ergonomic appraisal of educational desks. Ergonomics, Mar 1980, 23.3, 213-221. The comfort and functional utility of a classroom desk is a result of its design in relationship to the physical structure and biomeehanics of the human body. The educational desk must allow comfortable sitting postures to assist in the learning process. For the performance of different activities such as writing, listening and standing etc, a student has to assume different body postures, which demand contradictory geometrical configurations of the desk. The fixed type of desk whose geometry cannot be altered to suit an individual's anthropometric demands has been ergonomically evaluated in this study. A survey of lecture halls revealed large variations in the characteristic dimensions of the desks. Each relevant characteristic has been analysed and suitable values have been suggested. Where the already established values were not available, experiments were conducted, with a representative group of 40 students, to determine these suitable values.
Illumination 12.3.30 (80222) American National Standard Guide for school lighting. Lighting Design and Application, Feb 1978, 8, 1 2 - 4 2 ; abstr in Lighting and Research
Technology. This school lighting guide, prepared by the American IES and sponsored by the American National Standards Institute (ANSI/IES RP3-1977), supersedes one first published in 1962 and thus reflects the many changes in illuminating engineering occurring in the 15-year interval. A particular design criterion is the series of recommended limiting ratios between the luminance of the task and of other areas within the visual field. 45 references, a 3-page glossary and appendices on equivalent sphere illuminance and glare from luminaires are included. 12.3.31 (80231) Lighting for the aircraft/airline industries - Airframe maintenance.
Lighting Design and Application, Jun 1978, 8, 4 1 - 4 7 ; abstr in
Lighting Research and Technology. Prepared by an Aircraft Industry sub-committee of the American IES, these recommendations on lighting for airframe maintenance supplement existing recommendations ( 1975) on lighting for aircraft construction and
engine maintenance. A comprehensive table of recommended illuminances is provided. A typical aircraft maintenance 'flow diagram' is given and provides an introduction to the special processes involved in aircraft maintenance and the particular lighting requirements needed to meet them. 12.3.32 (80453) Green, J. A practical direct reading ESI meter for field use. Journal of the Illuminating Society, Jul 1980, 9.4, 247-251. Since the introduction of the ESI system for evaluating interior lighting, there have been various metering methods developed for measuring actual lighting installations. Presently, ESI can be measured either directly or indirectly. Indirecttype measurements include such instruments as the visual task photometer and the visibility meter. Such meters determine an intermediate value such as contrast or CRF (Contrast Rendition Factor) from which ESI is calculated. Direct-type meters include ones such as the Holophane ESI meter and DiLaura's cylinders which fit over footcandle meter cells. In the first case a subjective comparison is needed for results and in the second, intermediate calculations are again required.
Noise 12.3.33 (80258) Lehmann, F.A. et aI Inquiry about work conditions of sandblasters (Enquete sur les Conditions de Travail des Sableurs). (In French.)
Archives des Maladies Profession nelles de Medecine du Travail et de Securite Sociale, 1980, 41.1, 1 - 7 . The health conditions of 17 sandblasters were investigated. Four of them complain of deafness, two only have a normal audiogram. Those are the ones with the least exposure time (1 year and llA years). There is a significant correlation between hearing loss and exposure time. The noise levels were between 90 and 103 dBA. The respiratory symptoms and the results of spirometry (VC, FeV1, FEF2s_Ts) do not differ between the sandblasters and the control group. Oil mist, hydrocarbons, dust, carbon monoxide (from the air pulsed by a compressor) were evaluated in one factory: the values were below the TLV.
Vibration 12.3.34 (80270)
Johnston, M.E., and Wharf, J.H. The effect of 3 - 2 5 Hz vibration on the legibility of numeric light
emitting diode displays. Displays Technology and Applications, Jan 1980, 1.4, 1 9 4 - 1 9 8 . This paper describes the effects of 3 - 2 5 Hz sinusoidal vibration applied in b o t h the vertical and lateral axes on the performance of a reading task. The task was to read aloud numeric characters presented on a yellow high luminance light emitting diode display. The subjects were strapped into an ejection seat which was mounted on the same vibration platform as the display. Tests were conducted with the subject's head held b o t h against and just off the head rest. The results indicate that reading performance was affected most by lateral vibration, when the head was against the rest.
Motion 12.3.35 (80278) Ivergard, T. The fisherman's working environment - a cramped mini-factory which pitches and rolls (Fiskarens Arbetsmiljo: En liten Trang Fabrik som Gungar). (In Swedish.)Arbetsmil]o, Sep 1979, No 11, 1 4 - 1 9 ; abstr in CIS Abstracts (CIS 80-198). A questionnaire survey of some 1000 Swedish sea-fishermen showed: work on board trawlers is one of the most arduous occupations; bad working conditions are rendered worse by slippery deck surfaces on board a tossing ship, day/night shifts, exposure to bad weather conditions, noise, vibration, heat and cold. There are many accident hazards: falls on slippery decks; injury from trawl winch, drum and gallows; working conditions in heavy seas. A 7 0 - 7 2 h working week is not infrequent. Work in the narrow hold is rendered more difficult by noise reverberation and generally poor lighting. Ergonomics studies could provide solutions to some of these problems. 12.3.36 (80279) McLeod, P. et al The influence of ship motion on manual control skills. Ergonomics, Jul 1980, 23.7,623-634. The effects of ship motion on a range of typical manual control skills were examined on the Warren Spring ship motion simulator driven in heave, pitch and roll by signals taken from the frigate HMS Avenger at 13m/s (25 knots) into a force 4 wind. The motion produced a vertical r/m/s acceleration of 0.024g, mostly between 0.1 and 0"3 Hz, with comparatively little pitch or roll. A task involving unsupported arm movements was seriously affected by the motion; a pursuit tracking task showed a reliable decrement although it was still
Applied Ergonomics December 1981
247
Hits, D.S. An ergonomic appraisal of educational desks. Ergonomics, Mar 1980, 23.3, 213-221. The comfort and functional utility of a classroom desk is a result of its design in relationship to the physical structure and biomeehanics of the human body. The educational desk must allow comfortable sitting postures to assist in the learning process. For the performance of different activities such as writing, listening and standing etc, a student has to assume different body postures, which demand contradictory geometrical configurations of the desk. The fixed type of desk whose geometry cannot be altered to suit an individual's anthropometric demands has been ergonomically evaluated in this study. A survey of lecture halls revealed large variations in the characteristic dimensions of the desks. Each relevant characteristic has been analysed and suitable values have been suggested. Where the already established values were not available, experiments were conducted, with a representative group of 40 students, to determine these suitable values.
Illumination 12.3.30 (80222) American National Standard Guide for school lighting. Lighting Design and Application, Feb 1978, 8, 1 2 - 4 2 ; abstr in Lighting and Research
Technology. This school lighting guide, prepared by the American IES and sponsored by the American National Standards Institute (ANSI/IES RP3-1977), supersedes one first published in 1962 and thus reflects the many changes in illuminating engineering occurring in the 15-year interval. A particular design criterion is the series of recommended limiting ratios between the luminance of the task and of other areas within the visual field. 45 references, a 3-page glossary and appendices on equivalent sphere illuminance and glare from luminaires are included. 12.3.31 (80231) Lighting for the aircraft/airline industries - Airframe maintenance.
Lighting Design and Application, Jun 1978, 8, 4 1 - 4 7 ; abstr in
Lighting Research and Technology. Prepared by an Aircraft Industry sub-committee of the American IES, these recommendations on lighting for airframe maintenance supplement existing recommendations ( 1975) on lighting for aircraft construction and
engine maintenance. A comprehensive table of recommended illuminances is provided. A typical aircraft maintenance 'flow diagram' is given and provides an introduction to the special processes involved in aircraft maintenance and the particular lighting requirements needed to meet them. 12.3.32 (80453) Green, J. A practical direct reading ESI meter for field use. Journal of the Illuminating Society, Jul 1980, 9.4, 247-251. Since the introduction of the ESI system for evaluating interior lighting, there have been various metering methods developed for measuring actual lighting installations. Presently, ESI can be measured either directly or indirectly. Indirecttype measurements include such instruments as the visual task photometer and the visibility meter. Such meters determine an intermediate value such as contrast or CRF (Contrast Rendition Factor) from which ESI is calculated. Direct-type meters include ones such as the Holophane ESI meter and DiLaura's cylinders which fit over footcandle meter cells. In the first case a subjective comparison is needed for results and in the second, intermediate calculations are again required.
Noise 12.3.33 (80258) Lehmann, F.A. et aI Inquiry about work conditions of sandblasters (Enquete sur les Conditions de Travail des Sableurs). (In French.)
Archives des Maladies Profession nelles de Medecine du Travail et de Securite Sociale, 1980, 41.1, 1 - 7 . The health conditions of 17 sandblasters were investigated. Four of them complain of deafness, two only have a normal audiogram. Those are the ones with the least exposure time (1 year and llA years). There is a significant correlation between hearing loss and exposure time. The noise levels were between 90 and 103 dBA. The respiratory symptoms and the results of spirometry (VC, FeV1, FEF2s_Ts) do not differ between the sandblasters and the control group. Oil mist, hydrocarbons, dust, carbon monoxide (from the air pulsed by a compressor) were evaluated in one factory: the values were below the TLV.
Vibration 12.3.34 (80270)
Johnston, M.E., and Wharf, J.H. The effect of 3 - 2 5 Hz vibration on the legibility of numeric light
emitting diode displays. Displays Technology and Applications, Jan 1980, 1.4, 1 9 4 - 1 9 8 . This paper describes the effects of 3 - 2 5 Hz sinusoidal vibration applied in b o t h the vertical and lateral axes on the performance of a reading task. The task was to read aloud numeric characters presented on a yellow high luminance light emitting diode display. The subjects were strapped into an ejection seat which was mounted on the same vibration platform as the display. Tests were conducted with the subject's head held b o t h against and just off the head rest. The results indicate that reading performance was affected most by lateral vibration, when the head was against the rest.
Motion 12.3.35 (80278) Ivergard, T. The fisherman's working environment - a cramped mini-factory which pitches and rolls (Fiskarens Arbetsmiljo: En liten Trang Fabrik som Gungar). (In Swedish.)Arbetsmil]o, Sep 1979, No 11, 1 4 - 1 9 ; abstr in CIS Abstracts (CIS 80-198). A questionnaire survey of some 1000 Swedish sea-fishermen showed: work on board trawlers is one of the most arduous occupations; bad working conditions are rendered worse by slippery deck surfaces on board a tossing ship, day/night shifts, exposure to bad weather conditions, noise, vibration, heat and cold. There are many accident hazards: falls on slippery decks; injury from trawl winch, drum and gallows; working conditions in heavy seas. A 7 0 - 7 2 h working week is not infrequent. Work in the narrow hold is rendered more difficult by noise reverberation and generally poor lighting. Ergonomics studies could provide solutions to some of these problems. 12.3.36 (80279) McLeod, P. et al The influence of ship motion on manual control skills. Ergonomics, Jul 1980, 23.7,623-634. The effects of ship motion on a range of typical manual control skills were examined on the Warren Spring ship motion simulator driven in heave, pitch and roll by signals taken from the frigate HMS Avenger at 13m/s (25 knots) into a force 4 wind. The motion produced a vertical r/m/s acceleration of 0.024g, mostly between 0.1 and 0"3 Hz, with comparatively little pitch or roll. A task involving unsupported arm movements was seriously affected by the motion; a pursuit tracking task showed a reliable decrement although it was still
Applied Ergonomics December 1981
247