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INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS
Volume 10 Number 2, 2004
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CONTENTS:
Articles:
  PROTECTION OF HUMAN IN THE WORKING ENVIRONMENT
PROTECTION OF HUMAN AT THE WORKSTATION
NOTES
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Effectiveness of a Light-Weight Ice-Vest for Body Cooling While Wearing Fire Fighter’s Protective Clothing in the Heat
Juhani Smolander, Kalev Kuklane, Désirée Gavhed, Hakan Nilsson & Ingvar Holmér
The aim of the study was to examine the effects of wearing an ice-vest (ca 1 kg) on physiological and subjective responses in fire fighters. The experiments were carried out on a treadmill in a hot-dry environment. The physical cooling effect of the ice-vest was measured with a thermal manikin. The ice-vest effectively reduced skin temperatures under the vest. On average, heart rate was 10 beats/min lower, the amount of sweating was reduced by 13%, and subjective sensations of effort and warmth were lower during work with the ice-vest compared to work without it. Thermal manikin tests indicated that the useful energy available from the vest for body cooling was rather high (58%). In conclusion, the ice-vest reduces physiological and subjective strain responses during heavy work in the heat, and may promote efficient work time by 10%.
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Assessment of Future Workshop’s Usefulness as an Ergonomics Tool
Ingegerd Skoglind-Öhman & Houshang Shahnavaz
This study was carried out to assess Future Workshop (FW) regarding its usefulness as a participatory ergonomics method, using a descriptive evaluation design analysed by phenomenographical approach. The study was conducted among professional cleaners, health care personnel and miners, with a sample of 105 participating subjects in 8 different FWs.
Multiple methods, giving a combination of both qualitative and quantitative data, were used for data collection. Good involvement of participants was observed during workshops. Evaluations immediately after FWs and 3 months later showed a strong relationship with high correlation, indicating that the perception of FW participants was very positive. Interviews revealed conformity between developed problem identification and proposed changes. Participants’ own perceptions of FW’s influence on creativity depict their belief of developed ideas and solutions in order to identify and solve workplace problems.
FW is considered to be a useful ergonomics tool, and its qualities are related to structure and practical performance.
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An Analysis of Accidents Caused by Improper Functioning of Machine Control Systems
Marek Dźwiarek
The scope of this study covers events resulting from improper functioning of machine control systems. An accident model providing a basis for formulating a checklist for accident analysis has been developed. Data about 700 accidents were collected. An analysis has proved that in the group of accidents caused by improper functioning of machine control systems, serious accidents happened much more frequently as compared to the group of accidents with no relation to the control system. The reasons for the majority of incidents caused by improper performance of safety functions consist in the errors made by designers. In view of that, incorrect behaviour of a worker should be treated as a normal event instead of a deviation causing an accident.
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Working Conditions and Dentists’ Attitude Towards Proprioceptive Derivation
Montakarn Chaikumarn
Proprioceptive derivation (Pd), a new method of organising a dentist workstation as well as a working procedure, was introduced to Thailand. The aim of this study was to assess the working conditions and the attitude to Pd among experienced users. Questionnaires were distributed among 12 dentists. The results showed that all dentists chose to work in a sitting posture and mostly worked without breaks between patients. They spent less time on dental examination and crown and bridge therapy tasks. Solving problems in patients with physical limitations resulted in a low stress level. Seven dentists (58.3%) always used Pd and liked it. Five dentists (41.7%) sometimes used Pd, with 3 of them liking it. Only 2 dentists, who sometimes used Pd, did not like it because it could not cover all dental tasks and treatment, and it was difficult and complex.
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Cytotoxicity of Resorcinol Under Short- and Long-Term Exposure in Vitro
Jolanta Skowroń & Lidia Zapór
Cytotoxicity of resorcinol to 3T3 fibroblast in short- (3 hrs) and long-term (72 hrs or 6 weeks) exposure was investigated. The effects of resorcinol on cell viability (neutral red uptake, NRU assay), mitochondrial function (MTT assay) and total cell protein (Kenacid Blue assay) were estimated. As a model for long-term exposure an INTEGRA CL 6-WELL bioreactor was used. The concentrations of resorcinol producing 20, 50 and 80% inhibition of cell growth in the NRU test were lower than in the MTT test after 3 hrs of exposure. The use of an INTEGRA CL 6-WELL bioreactor allows continuous culturing and exposure to test chemical of cells for several weeks, but the strong adhesiveness of fibroblast and forming aggregates make it difficult to remove them from chambers. Resorcinol in concentration of 1 ìg/cm3 did not decrease the viability of cells to 50% of control in long-term exposure in the bioreactor.
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Musculoskeletal Symptoms as Related to Ergonomic Factors in Iranian Hand-Woven Carpet Industry and General Guidelines for Workstation Design
Alireza Choobineh, Mohammadali Lahmi, Houshang ShahnavazReza Khani Jazani, & Mostafa Hosseini
Carpet weaving is a high risk occupation for developing musculoskeletal disorders (MSDs). The objectives of the present study, which was carried out in the Iranian hand-woven carpet industry, were determination of the prevalence of MSD symptoms, identification of major factors associated with MSD symptoms and development of guidelines for workstation design. 1,439 randomly selected weavers participated in this study. A questionnaire was used to collect data on MSD symptoms. The results revealed that the prevalence rates for symptoms in different body regions were high as compared to the general Iranian population (for neck, back and large joints, both p < .0001). The results of multivariate analyses showed that major ergonomic factors associated with musculoskeletal symptoms were loom type, working posture, daily working time and seat type. Based on the results, some general guidelines for designing weaving workstations were developed. A prototype test showed that the new workstation was acceptable for subject tests and that it improved working posture.
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Identification of Ergonomic Issues That Affect Workers in Oilrigs in Desert Environments
Ashraf A. Shikdar
The main objective of this research was to conduct an assessment of ergonomic-related problems in oilrigs in a desert environment. A checklist, physical audit and medical records were used in the investigation. The results showed significant health, environment and work-related problems that could be attributed to ergonomic deficiencies in the work system of the oilrig. Some major ergonomic issues identified were hard physical work, back pain, discomfort, hot environment, long shift, and diverse schedule. Ninety-four percent of the employees perceived the workday as very long, 79% were dissatisfied with the work schedule, while 61% of the employees perceived the summer work environment as extremely hot. Ergonomics should be considered in the work system design so as to reduce or eliminate problems in oilrigs in hot desert environments.
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Speech Intelligibility of the Callsign Acquisition Test in a Quiet Environment
Misty Blue, Celestine A. Ntuen & Tomasz Letowski
This paper reports on preliminary experiments aimed at standardizing speech intelligibility of military Callsign Acquisition Test (CAT) using average power levels of callsign items measured by the Root Mean Square (RMS) and maximum power levels of callsign items (Peak). The results obtained indicate that at a minimum sound pressure level (SPL) of 10.57 dBHL, the CAT tests were more difficult than NU-6 (Northwestern University, Auditory Test No. 6) and CID-W22 (Central Institute for the Deaf, Test W-22). At the maximum SPL values, the CAT tests reveal more intelligibility than NU-6 and CID-W22. The CAT-Peak test attained 95% intelligibility as NU-6 at 27.5 dBHL, and with CID-W22, 92.4% intelligibility at 27 dBHL. The CAT-RMS achieved 90% intelligibility when compared with NU-6, and 87% intelligibility score when compared with CID-W22; all at 24 dBHL.
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Do Children Have One Third Less Peripheral Vision Than Adults?
Peter A. Hancock
The following report is a case study example of how problematic information can invade and percolate through the literature on forensic human factors and ergonomics. Initially, a highly doubtful assertion was used to bolster an argument made in a legal case of wrongful death. The assertion was supported through reference to a number of cited works. When the trail of evidence was pursued, however, it became clear that diverse citations had all branched from one, single, original and doubtful source. The fundamental issue, whether children have one third less peripheral vision than adults turns out to be much more complex than the original, simplistic spatial conception suggested. The case study illustrates the importance of ascertaining original citations and is yet another example of the frustration that often accompanies forensic activity where financial and legal concerns frequently over-ride the fundamental search for knowledge.
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