Vol 7 No 4 (2015)

Published: 2015-12-15

Original Article(s)

  • XML | PDF | downloads: 326 | views: 726 | pages: 166-171

    One type of electromagnetic fields, based on frequency range, is Extremely Low Frequency (ELF) fields. There are lots of reports about measuring ELF-magnetic field (MF) in substations, power plants, cities and etc. This study aimed to compare the difference between measurement of three-axis and single-axis probe MF meters. ELF-MF was measured by TES-1394 MF tester (three-axis probe) and HI-3604 ELF survey meter (single-axis probe) in selected power plant and the resultant of three MF components (X, Y, and Z) was calculated based on equation. Field measurement was based on IEEE std 644-1994. In the generator building, minimum, maximum, and mean values of the magnetic flux density measured by the three-axis device were greater than those measured by the other two methods. Besides, the maximum value of the resultant method was greater compared to the measurements related to the other two methods, but the means of magnetic flux density by the three-axis device was greater than the resultant and maximum axis value. However, a significant difference was found between the maximum axis value and the results of the three-axis device (P=0.022). The best and most reliable way to measure MF is using a device with a three-axis probe and measuring the maximum MF by the singe-axis device cannot be reliable. Moreover, in the absence of a device with a three-axis probe, if there is a single-axis probe, the best we can do is obtaining the resultant from the three directions of the field.

  • XML | PDF | downloads: 287 | views: 493 | pages: 172-176

    Health, safety, and environment management are dedicated a vast area in which ergonomics aspects known as one of the related aspects. In the following case study, the occupational hygiene by ergonomic intervention is focused. One of the prevalent activities among industrial sectors' workers in the developing countries is manual lifting tasks and other related physical activities, which are crucial tasks not only in terms of occupational health but also about safety. Such activities are known as one of the major risk factors of work related musculoskeletal disorders. In this case study, the mentioned tasks were focused in a food manufacturing company in Tehran-Iran where there are some kinds of plants. Some parts of workers' activities including lifting, lowering and carrying the boxes and bulky body packages. In the sesame seeds cleaning and peeling plant, some of the workers should transfer some amounts of sesames from centrifuge as an origin to kilns as a destination area by carrying the carts and lifting the tank to empty sesames into furnaces. Nordic Musculoskeletal Questionnaire (NMQ) assessed the psychophysical aspects of this activity, and anthropometry measurement was done among the 48 sampled workers. Ovako Working-posture Assessment method (OWAS) was also used to assess the body postures. The gathered data and in-depth observation showed the necessity of cart design to improve workers health in terms of ergonomic factors. A new cart was designed considering with economics limitations. This new cart would change lifting stress and pushing tasks to better condition.

  • XML | PDF | downloads: 553 | views: 827 | pages: 177-186

    Various aspects of work and occupational diversity and the complexity of the nursing profession have a significant impact on the incidence rate of unsafe acts and consequences of accidents. In this regard, safety attitude will have a significant impact on occupational accidents among nursing personnel. The aim of this study was to assess safety attitude among nurses and its relation with occupational accidents among teaching hospitals of Kerman University of Medical Sciences. This cross-sectional study was conducted on 244 nurses in Kerman, Iran in 2015. Tools for gathering data were Demographic and Organizational Questionnaires, Safety Attitudes Questionnaire (SAQ) and Occupational Accidents Questionnaire. Data was analyzed using SPSS 21 statistical software and descriptive statistics and statistical tests including Pearson correlation, independent t-test and ANOVA. The highest and lowest attitude scores were related to teamwork climate scale (58.9) and perception of management (38%). The stress recognition scale had significant correlations with each of the other scales. Reliability of the questionnaire was high, (α=0.872), and scale reliability ranged from α=0.82 to α=0.908 for the six scales. Chemical splash to eyes, in more than 3 times accident frequencies, had the lowest percentage (1.03%), and exposure to blood or other body fluids, had the highest percentage, (37.11%). There was a significant relationship between exposure to blood or other body fluids and traumatic backache while changing patient’s positions with safety attitude (P<0.05). With regard to the relationship between safety attitude and occupational accidents, managers, by increasing their awareness of safety knowledge, improved incentive system, collaborative management, employee safety and dealing with occupational stress and finding the effective causes of patient safety can develop employees' attitude to safety.

  • XML | PDF | downloads: 243 | views: 293 | pages: 187-196

    The aim of this study was to design and build a software for noise propagation prediction (indoor and from indoor to outdoor spaces) being commonly used in industry. In this regard, firstly a mathematical complex model was created based on existing relationships on noise propagation in indoor spaces and transmission through the walls and propagation in outdoor spaces. To model noise propagation from indoor to outdoor, the function of this model is based on meshing the wall which is effective on outdoor receiver point. By analyzing the required inputs and outputs and designing and documenting the process algorithm, the mathematical model was created and the software was built. In the process of meshing the wall, the software divides the effective wall into 20 parts in length and width and calculations related to sound pressure level on inner wall surface, transmission loss through the wall and leakage from the pores are performed on these meshes. The built software was designed in five forms. Form one for defining hall dimensions and areas of used materials, form two and tree for defining sound sources inside the hall and form five for defining and managing materials were designed. Form four was used for completing required information and monitoring calculation results and software outputs. The software was run with the input data of a gas power plant and outputs were analyzed. The average relative difference between outputs of software (sound pressure levels in given points) and field measurements was below 5%.

     

  • XML | PDF | downloads: 298 | views: 329 | pages: 197-201

    Tiller is a hand-tractor is used in Agriculture. The noise emitted from Tiller may affect auditory system of operators seriously. The purpose of this study was to evaluate the noise exposure in operators of this device. In this study, 36 cultivator tillers were examined. Measurement of sound was conducted in different mode using sound level meter model of cell 450 based on ISO 7216 standards. Assessment of noise exposure was performed in state that tiller was in its maximum of working power, but, frequency analysis and determining of dominant frequency was performed in state that Tiller was in the middle of its working power. In the present study, experiments were conducted in three operational conditions i.e. static and neutral mode (idling), land plowing with gear 1 and land plowing with gear 2. Results of this study showed that 8-hour exposure level with noise in 3 different modes is 90, 94.73 and 95.17 dB respectively, which is more than standard. Results of Frequency analysis indicated that in each 3 modes, frequency 2000 was dominant frequency. In addition, the maximum level of exposure was in this frequency. Exposure to noise at frequency of 2000 in neutral mode, land plowing with gear1and gear 2 was respectively 81.30, 86.97, and 88.11 dB. In all measured situations, exposure to noise was higher than the standard limit and there was risk of hearing loss. Thus, further studies and control measures are necessary. 

  • XML | PDF | downloads: 401 | views: 463 | pages: 201-208

    The objectives of this research were to study the correlations of heat strain score index (HSSI) and values of wet-bulb globe temperature (WBGT) index with physiological parameters such as core body temperature, heart rate, and blood pressure of workers exposed to heat stress in a glass manufacturing plant in order to determine the reliability of HSSI. This cross sectional study was carried out on 72 production, packing, and quality control male workers of a glass manufacturing plant. The WBGT values were recorded according to standard No. International Standard Organization (ISO) 7243 heat stress standard during the summer season in July–August 2013. Metabolic rate for each task was estimated according to standard No. ISO 8996. Body core temperature and heart rate were monitored according to standard No. ISO 9886. HSSI questionnaire was used to evaluate heat strain. The data were analyzed using Pearson and Spearman correlation coefficients and linear regression test. The maximum WBGT value (30.20±1.06ºC) was recorded in production unit of plant. The scores of HSSI index in production, packing, and quality control operators were 23.16±1.9, 21.56±1.69, and 21.43±2.04, respectively. The highest correlation coefficient was found between the measured WBGT values and core body temperature (r=0.462). Positive correlations between the values of WBGT index and studied physiological parameters indicated that the WBGT as the most widely accepted index is better than HSSI for the assessment of thermal stress in glass manufacturing industry.

  • XML | PDF | downloads: 309 | views: 626 | pages: 209-214

    Noise and vibration are the common problems in industrialized countries which can affect individual's job performance. The present study aimed to investigate the combination of the whole body vibration and the noise and their effects on the students' mental performance in the laboratory setting. Twenty male students of Tehran University of Medical Sciences, Tehran, Iran were randomly selected to participate in this experiment. Each participant attended in a test consists of 9 stages through the single exposure to the low frequency noise with two sound pressure levels of 75dB and 85dB and two vibration modes with 0.8 m/s2 and 1.1 m/s2 acceleration. In addition, the combination of the exposure with variable noise and vibration were tested. The control mode that was included the combination of the background noise (35dB) and vibration was studied. Finally, this study examined the relationship between student cognitive functions and exposure with noise as well as whole body vibration in shallow, intermediate and deep level by mathematical calculation test. The results showed that at shallow level, the whole body vibration, the noise as well as their interactions did not affect the mental performance of student. However, in intermediate and deep levels, the differences are statistically significant. Noise and vibration are two affecting factors over individuals’ mental performance. The amounts of exposure to these variables are crucial. Therefore doing activities with more complex mental tasks require lower levels of physical stressors such as noise and vibration in the environment in order to reduce the error rates in the work.

  • XML | PDF | downloads: 149 | views: 274 | pages: 215-221

    Although the International Labor Organization (ILO) has reported that two-thirds of the world’s occupations belong to women, a few studies regarding employed women have been conducted. The present study aimed at conducting survey on scientific outputs regarding women’s occupational health. This cross-sectional study was conducted from 2010 to 2014 at five-year intervals on a number of hygiene-based journals regarding workers’ health at Scimago data center. Surveyed articles were categorized on the basis of type of work-related risk factors, methodologies, types of women jobs. Articles were distributed under the terms of the subjects. Out of 4,197 published papers on 17 subjects related to occupational hygiene indexed by Scimago, 203 papers (4.8%) were allocated to women’s health. With regards to women’s health, health staff had taken the most papers with 37.7%. Most of the studies were cross-sectional and on hazardous chemical agents. Due to low range of articles with the issue of occupational hygiene, it was concluded that occupational hygiene researchers have not focused much attention on this occupational group.