Journal of Health and Safety at Work

Introduction: Workers employed in outdoor occupations such as farm working, especially during rice harvest, are exposed to hot and humid environments that put them at risk for different kinds of heat-related disorders or heat stress. The aim of this study was to determine the susceptibility to heat-related disorders and prevention methods among a group of agriculture workers in one of the northern cities in Iran.

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Method and Materials: This study is a descriptive-analytical and cross-sectional study which was done among 340 agricultures workers in a city (Sorkhrood) in Mazandaran province. The samples were collected from 42 villages using two stage cluster-randomized sampling method. The data were collected by means of tailor-made data collection sheet and analyzed using descriptive statistical indexes and Chi- square test, and p<0.05 was considered as significant.

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Results: The findings indicated that the mean values of age and years of experience were 42.8 and 26 years, respectively. Almost half of the agriculture workers were overweight or obese, 34% illiterate, and 15% encountered chronic illnesses. Ninety five percent of the workers were not informed about prehydration in hot environment and none of them know about the consumption of electrolytes. According to Chi-square test result, there were no significant differences between the prevalence of headache as one of the early signs of heat –related disorders and other related factors.

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Conclusion: According to the results, agriculture workers based on their age distribution, education, body mass index, health knowledge, drug use and incidence of chronic diseases, are very vulnerable to heat-related disorders. Therefore, training on recognizing the early signs and doing control measures as essential element in heat stress prevention should be seriously considered.

Introduction: Many methods exist for evaluating ergonomic risk factors for LBP at workplace, including biomechanical, physiological and psycho-physical methods. Digital Human Modeling (DHM) as a tool based on computer for ergonomic evaluation that Because having advantages such as saving time and costs in assessment and actively evaluation of ergonomic solutions in the digital environment.Aim of this study was evaluation occupational causes of LBP with the use of digital human modeling.

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Method and Materials: This study was a case quasi-experimental study in the engine assembly of the car manufacturing industry was conducted. First, The characteristics of job and risk factors for low back pain In all workstations were documented, then workstations with high risk of low back disorders were selected. Finally, a workstation for simulating and evaluating in the human digital modeling softwares, which includes 3DSSPP and Catia were selected. A total 22 posture of the lifting and lowering moment of the three tasks of workstation selected for simulation. After evaluation in the digital environment, the risk areas identified and solutions were presented.

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Results: The results showed that compressive and shear forces on the L5/S1 disc increased with increase of anthropometric dimensions and Horizontal distance from the body and decrease of height Lowering the site, and the percentage of people capable to perform a task in joint, decreased with increase of anthropometric dimensions. Ligament strain in postures with sever bending trunk were more increasing. RULA scores increased with the Unsuitable conditions of back and arms. High risk areas, were mainly related to the low height of pallets in lifting and lowering and high Horizontal distance from the body.

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Conclusion: According to The results of this study, Biomechanical Causes for LBP, including anthropometric characteristics (height and weight), Horizontal distance of object to the body, height of lifting and lowering location and trunk bending and torsion. This study showed that DHM is an effective tool in the evaluation of job tasks and workplace design, that can be identified risk area in each task and to achieve the ideal design. Using DHM can be implement Desired solution in a virtual environment and With the re-evaluation, Be sure of having effective solutions in the real environment.

Introduction: Work-related musculoskeleta ldisorders (WMSDs) of upperlimbs (UL)in the last 35 years have become extremely widespread, reaching epidemiclevels, inalladv ancedindustrializedcountries. They are considered the main cause of disability, time off work, and requests for healthcare

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Method and Materials: For detailed risk assessment, ISO -11228-3 is the preferred method. It is recommended for the specific purposes of ISO -11228-3(2007) because, given the knowledge at the time of publication, it considers all the relevant risk factors, is also applicable to “multitask jobs”, and provides criteria - based on extensive epidemiological data - for forecasting the occurrence of UL-WMSD (upper limb work-related musculoskeletal disorders) in exposed working populations. In this method is the ratio between the number of actual technical actions, ATA, carried out during a work shift and the number of reference technical actions, RTA, for each upper limb, specifically determined in the scenario under examination.

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Results: Results shown in 4 workstations include 35 task in an automotive industry. One of them is red and another’s are green.

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Conclusion: This method is suitable, quickly and very easy to use for assessment of ergonomics situation in work.

Introduction: Risk assessment of Toxic or hazardous chemicals enables the Industrial Hygienists to make the appropriate decision in providing healthy work place. This project was conducted in an assembling plant,(4workshop) of an Automobile Industry in IRAN with 2 types of welding operations, including GMAW (CO2 welding) and Spot resistance welding operations.

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Method and Materials: Welders` exposures were assessed via collecting 143 breathing zone air samples based on NIOSH 0500 method. Risk assessment was carried out using Singapore recommended method.

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Results: Finding showed that the mean of welders exposure in GMAW and Spot resistance welding operations 5.61 ± 5.78and 2.38± 2.15 mg/m3, respectively(p<0.05). The results showed that in GMAW welders had the highe exposure in comparison with Spot resistance welders (p<0.05). The findings also demonstrated that the risk rate of GMAW welders were high, while this rate for Spot resistance was low.

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Conclusion: more hygienic attention is needed for GTAW welders. Control approaches are required including effective engineering control, conduct air monitoring, biological monitoring training, adopt respiratory protection program, develop and implement safe and correct work procedures and finally reassess the risk after all the controls have been done.

Introduction: Heat stress is considered as physical hazard, in working environments. The effects of working in hot environment include: muscle cramp, fatigue, loss of consciousness, perception and heat exhaustion.The purpose of this study was to evaluate heat stress and identify hazardous workstations in terms of heat stress in one of the Teheran's forging industries, using WBGT index.

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Methods and Materials: This Cross-Sectional study has been done in one of the forging industries of Tehran on five successive days during the warmest period in Summer 2010. for measurements, a calibrated WBGT meter according to ISO7243 standard was used. All workers who were exposed to radiant heat in this industry, had more than 3 years continuous work history, So they were well accommodated to the environment. For statistical analysis SPSS14 and Exell2007 software were used.

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Results: In this study, the WBGT of all workstations in the exposed to the furnace were estimated. the workstations average WBGTTWA were calculated 27.97°C, Which were higher than the threshold limit value according to ACGIH recommendation. The ANOVA and Post hoc(LSD) tests showed significant difference in the radiant heat (P-value<0.01), and WBGT index (Pvalue<0.05), between three different heights of the body. The observed differences between head and waist were not significant, but the difference between two heights and the ankle were significant.

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Conclusion: Heat stress in workers exposed to the radiant heat sources were higher than the Threshold limit value, which recommended by ACGIH. The results also indicated that the main problem were the radiant heat, especially in the head and waist height. Hence in order to decrease the radiant heat, some control solutions were Suggested.

Background: Generally every different machines which are implemented in industries, agriculture and transport systems exposed human to excessive vibration. The produced vibration can reduce comfort and productivity and also cause adverse effect on human health and safety. Long term human exposure to high vibration levels may lead to physiological disorders.

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Material and methods: This paper presents the results of an experimental study which is done on 584 students of Tehran University of medical sciences. The data was gathered by interview and a validated questionnaire. In this study the stimulus was produced by a calibrated 3 axis vibrated seat. The voltage of stimuli was 90 and 95 V in two different frequencies of 20 and 25 Hz in two axis of x and y. During exposure the transferred whole body vibration was monitored by a calibrated whole body vibration meter.

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Finding: The results of this investigation showed that whole body vibration effect on mental disorder is significantly higher among female compared with that of in male. The disorder induced by frequency of 25 Hz was three times higher than that of produced by 20 Hz. The frequency of mental disorders was increased by rising vibration acceleration. It was also found that taller people are slightly less sensitive to the range of tested frequencies and acceleration compared with of shorter one.

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Conclusion: A significant relation between height and mental disorders was found in this study which can be used on whole body vibration exposure management.

Introduction: Low back pain (LBP) is a common and costly health problem. It has high prevalence in nursing job and caused shortage of nursing staff. This study was conducted to determine the prevalence of LBP, knowledge level of LBP risk factors and assess relationship between LBP prevalence and nurses’ knowledge level of LBP risk factors among nurses of Shiraz University of Medical Sciences (SUMS).

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Material and Method: In this cross-sectional study, 118 randomly selected registered nurses participated from SUMS hospitals with at least one year of job tenure. In order to assess nurses’ knowledge of LBP risk factors, a self-administered survey questionnaire consisted of four parts was used as data collecting tool. Statistical analyses were performed using SPSS (version 11.5). Duncan, T-test and ANOVA tests were used for data analysis.

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Result: LBP prevalence rate was found to be 79.7% (94 nurses) during the previous year from which 12 nurses were male (63.2%) and 82 nurses were female (82.8%). Nurses’ knowledge level of LBP risk factors in different hospitals was not significantly different. The Results showed that nearly half of the nurses had poor knowledge about LBP risk factors and the remaining had good knowledge level. The main source of information about LBP risk factors among nurses were related to their university education.

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Conclusion: A high prevalence of the LBP was found among nurses working at SUMS hospital. Knowledge level of nurses about LBP risk factors needs improvement. In addition to university education, which is the main source of information of nurses about LBP risk factors, on-the-job training seems essential in this field.

Introduction: Nowadays, in many different fields of chemical agents several experimental researches is being done on volatile organic compounds using gas chromatography, which is time consuming and expensive methods. Photo ionization detector as an alternative method is used by researchers in this field. This feasibility study was conducted to replace the photo ionization detector with gas chromatography.

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Material and Method: In this study, after making pre-determined concentrations of Xylene, the results of measurements using photo ionization detector and reference method were compared. This comparison was done in 4 humidity levels and 3 concentration ranges.

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Result: The results showed significant differences in photo ionization detector readout and the reference method. However correlation coefficient of two methods were more than 0.99 in all cases regardless of the humidity rate.

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Conclusion: Although the results obtained by the photo ionization detector are different from those extracted from the reference method in the current study, due to linear response of the method correlation coefficient was at good level. Consequently, in case of studying concentration changes in a research, this alternative method would be applicable, otherwise calibration of the photo ionization detector with the target material is recommended.

Introduction: Emission of volatile organic compounds through industrial processes to the environment has been received more attentions currently. Photocatalytic oxidation process as a new emerging technique in air purification can be substituted for conventional techniques such as activated carbon adsorption. In photocatalytic oxidation process, pollutant molecules decompose to water and carbon dioxide molecules. The objective of present study was the examination of influencing parameters such as concentration, relative humidity, and superficial gas velocity on photocatalytic oxidation of Methyl Ethyl Ketone (MEK) in a fluidized bed reactor.

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Material and Method: In this study photocatalytic oxidation of MEK was examined in a fluidized bed reactor. Gamma alumina coated titanium dioxide particles under ultraviolet light were used as photocatalyst. The efficiency of photocatalytic oxidation process was determined using measurement of MEK concentrations at the inlet and outlet of the fluidized bed reactor.

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Result: The study of MEKphotocatalytic oxidation was carried out in the concentration range of 100 to 800 PPM with 25% and 45% relative humidity. Photocatalytic degradation of MEK at the relative 45 % humidity was slightly lower than 25 %. Increasing MEK concentration from 200 to 800 PPM was led to decrease in degradation efficiency. At concentrations of 100 and 200 PPM MEK, increasing superficial gas velocity did not change the degradation efficiency, whereas, at concentrations of 200 to 800 PPM, increasing superficial gas velocity resulted in decrease in MEK degradation.

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Conclusion: In photocatalytic oxidation of MEK, there is a competitive adsorption between water and MEK and at higher relative humidity degradation of MEK decreases. In the fluidized bed reactor increasing superficial gas velocity causes decrement in MEK photocatalytic degradation.Increasinginitial concentration of pollutant results in decreasing ofphotocatalytic efficiency due to the limited number of active sites on the catalyst surface.

Introduction: work related musculoskeletal disorders are the most wide spread type of occupational diseases among workers. Awkward body postures during work and manual material handling are among the most important risk factors of musculoskeletal disorders in different jobs. Due to importance of recognizing these factors prevalence and risk factor of work related musculoskeletal disorders, this research was aimed to study the among employees of Kashan City’s Saipa automobile industry in 2011.

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Material and Method: This study is a descriptive-cross sectional study conducted among workers with manual material handling 37 activities and 84 work duties. To recognize musculoskeletal disorders, body map questionnaire was applied and occupational risk factors were evaluated using Key Index Method (KIM). Data was analyzed using SPSS and Excel software.

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Result: Highest prevalence of musculoskeletal disorders was in low and upper back region (%92). Based on the results from KIM, workers in the installing the tire, shuttle-aided fitting of seat, and engine work station had higher risk level with the scores of 66, 52 and 52, respectively. Risk level among three individuals (%3.6) was at 1, 40 (%47.6) at 2, 38 (%45.2) risk level 3, and 3 (%3.6) at 4.

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Conclusion: Awkward body posture, improper twisting and flexion of low back were major risk factor among worker doing manual material handling tasks. Regarding the high prevalence of musculoskeletal disorders, appropriate ergonomic interventions such as engineering and organization interactions can reduce this risk factors (posture, heavy load, duration, workplace conditions) as much as the risk level reach to an acceptable level.

Introduction: Eye discomforts and headache are prevalent among computer users. The aim of present study was to determine eye discomforts and headache associated with computer use among dormitory students of Tehran University of Medical Sciences.

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Material and Method: In this cross – sectional study, data were collected using MIRTH (Musculo skeletal Injury Reduction Tools for Health and Safety) questionnaire. The results were Analyzed using SPSS Software and with descriptive statistical indexes as well as correlation test.

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Result: of the 744 distributed questionnaires, 631 students completed the questionnaire (84.4%). The mean age for the studied population was 22.72± 3.6 years. The relative frequency of eye discomforts for the female and male student was 76.38% and 70.11% respectively. The correlation test showed significant relationship between eye discomforts as well as headache with gender, work hours’ with a computer per day and glass use (P-V < 0.05). Also, the correlation between eye discomforts and headache was statistically significant (P-V < 0.01).

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Conclusion: Eye discomforts and headache relating to the computer uses are prevalent among students. The condition is more prevalent among females and prolonged computer users. Interventional and training programs should be considered to prevent and reduction of related problems.

Introduction: Today’s, defective and faulty equipments lose a large part of them energy as noise and vibration which beside their financial costs can be hazardous to the health of people. Vibration as a physical agent can cause an adverse health effect on human to nervous system. These effects, based on body region can be as specific or general systems. Digestion system has a natural vibration of 3-8Hz frequency. When the digestive system is exposed by such vibration, it can make impairment on that system. This study aimed to study vibration effect on digestion irregularities.

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Material and Method: This was a retrospective case-control study conducted in a food industry. The number of 103 workers digestive problem and 431 healthy workers were selected as population study. Exposure to the vibration in the different parts were measured. People with more than 100 dB was considered exposed group. Then, after determining the number of exposed and non exposed groups, data were analyzed using statistical methodologies.

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Result: The acceleration level of vibration was 109.8 dB in the packing section, which was less than standard limit (118.8 dB). Study population had a managed of 24-57 years old with 4-15 years of job tenure. In 59.2% of case comparing to 22.7% of control group were exposed to the vibration. The odds ratio (OR) of prevalence rate of digestive problem among exposed group was 6.3 times more than non exposed group people, in risk of gastrointestinal complications.

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Conclusion: Beside of the other risk factors of digestive problem, vibration can be also an effective cause of adverse health problem: Even by lower level of digestive problem can be seen in the exposed people. So, we suggest in the workplace with vibration risk factor, a digestive health exam be take general medical beside periodic examination. Moreover, it is recommended that researches related to the vibration is widely developed and the vibration standard limits is revised, accordingly.

Introduction: Due to the increasing population and the need for setting in cities, we witness an increase in high-rise building in Iran. Moreover, because of the ambiguity and complexity, they have various risks potential. Health problems are among this risks for the residents. These risks have short term or long term effects,which can cause illness or even death.

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Material and Method: In the present study, health risks in high-rise buildings are identified, assessed and ranked. Health issue are identified by conducting interview with experts in high-rise building an using specific health and safety related checklists. Due to ambiguous nature of risks and existence of uncertainly, fuzzy logic technique with trapezoidal distribution was used for quantification. Finally, after risk evaluation and calculation of critical degree of each risk, the risks were ranked.

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Result: Risk factors obtained over 0.5 for most of the risks that indicate the importance of Health in high-rise projects during construction phase. The results also showed that the health risks should be assessed before the start of the project in order to reduce or eliminate their impacts.

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Conclusion: Safety risks in High-rise Building projects is very important. These risks have many impacts directly and indirectly on the time, quality and costs of projects. Therefore, evaluating and controlling each health risk in the design and implementation phases are essential. Most of the risks factors identified in this study, can be prevented by using personal protective equipment. The role of the training people involved in this projects are essential to use personal protective equipment.

Introduction: Occupational exposure to manganese can cause neurobehavioral symptoms. The aim of present study was to survey neurobehavioral symptoms of welders exposed to manganese- containing welding fumes and compare the frequency of these symptoms with unexposed group.

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Material and Method: Twenty seven of welders as exposed group, and 30 administrative workers as unexposed controls, were participated in this study. Neurobehavioral symptoms data were gathered using Q16 questionnaire. Manganese concentrations were determined according to the NIOSH 7300 method. After preparing of blood samples using microwave assisted acid digestion method, all samples were analyzed to determine manganese by graphite furnace- atomic absorption spectroscopy (GF-AAS).

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Result: The mean exposure to air manganese was 0.023± 0.012 mg/m3. Manganese concentrations in blood samples of welders (15.88± 7.11 µg/l) were significantly higher than unexposed workers (9.37± 8.70 µg/l), (P-V<0.05). The frequency of neurobehavioral symptoms of welders was significantly higher compared to unexposed workers (P-V<0.05). The correlation between neurobehavioral symptoms and blood manganese was significant for welders (P-V<0.05).

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Conclusion: Welders’ exposure to manganese and its potential health effects should be evaluated periodically and effective control measures should be applied in order to to prevent neurobehavioral symptoms.

Introduction: Introduction: Thermal comforts are one of the most human concerns in working as was as living environments in the past half century. Thermal comfort is the condition in which people are satisfied with the thermal environment, mentally. One of the new heating system employed in individual units is radiant heating system .The purpose of this study was to investigate the performance of radiant ceiling heating system and its impact on thermal comfort of workers.

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Material and Method: In the present analytical-descriptive study, the designed radiant heating systems were investigated in two repair and maintenance units, in Hamadan gas pipeline operation center. Firstly, the environment parameters, witch impact thermal comfort, were measured before and after using radiant heating system, in both understudy units. Then, wind chill index, thermal comfort indices, PMV and PPD were calculated. In addition, PPD and PMV were determined, based on workers subjective feeling by a questionnaire distributed among 22 workers.

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Results: According to the results, the radiant heating system in unit 1, has reduced the wind chill index by 42.3 Kcal/ m2.h, witch is not considered to be significant. In unit 2, wind chill index has been decreased by 109.3 Kcal/ m2.h, witch mean that thermal comfort has been changed from cold to an optimum environment. PMV n unit 1 went up by 37% after turning the system on, witch is equal to 17.24% increase in workers satisfaction. However, in unit 2, the workers satisfaction was 14.3% higher in comparison with unit 1.

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Conclusion: Due to large space of these industrial units, producing appropriate heating by convection mechanism is too difficult and expensive. The results confirmed that if radiant heating system applied based on scientific design principles they could be effective in promotion of thermal comfort due to heating surrounding surface by radiant and also reducing fuel consumption.

Introduction: In developing countries, promotion of road safety is of crucial importance. This paper presents the status of road safety in Iran during 2001 - 2006.

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Material and Method: The status of road safety in Iran was surveyed in this descriptive study using road safety indicators a in macro level. Firstly, 46 indicators were identified after studying almost all indicators related to the road safety. After consulting of views with road safety experts and considering the reliable existing data, 11 indicators were selected to study the safety status of the roads. Then, all essential data for determining each indicators were collected from related organizations and institutes. All indicators were determined and evaluated in the last step.

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Result: The results revealed that during the period of 6 years, death toll has been increased by 9 deaths per 100000 person of the population. Moreover, application of seat belt and safety helmet has been increased by 20% and 18%, respectively. It also indicated that the number of motorists and the length of paved roads have been increased by 20%, and 10%, respectively. The net income per capita has also grown from 5884 US$ to 7968 US$ and the life expectancy has gone up from 68.9 years to 70.9 years, the percentage of the literate population has grown by 2% (from 76% to 78%) and the human development index has increased from 0.721 to 0.759. The results of the present study showed that the increased level of death toll per 10000 vehicles and the increased level (%) of seat belt as well as helmet application, paved roads, urbanization, the net income per capita, life expectancy, literacy and human development index were statistically significant and R2 coefficient for this factors was 0.84, 0.9, 0.994, 0.9, 0.97, 0.82, 0.69 and 0.84 respectively.

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Conclusion: According to result of the present study, roads safety were not in an appropriate level. The roads safety status can be determined using road safety indicators to be applied for road safety promotion.

Introduction: currently, stress is known as one the most important issue among societies which may have positive or negative results. Stress is caused when there is not a harmony between job demands, capabilities and desires of a person. Most of the behavioral, physical and mental disorders are results of job stress. The objective of this study was Validity and Reliability analysis of NIOSH Generic Job Stress Questionnaire (GJSQ), in order to have an appropriate tool for evaluation and analysis of job stress in Iran.

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Material and Method: In this study, 228 members of Tehran fire-fighting office were chosen according to categorical and clustering sampling, methodology and they completed NIOSH Generic Job Stress Questionnaire (GJSQ). For Validity and Reliability of questionnaire, 20 persons of the group were chosen for content validity analysis of the questionnaire. For Reliability analysis of the result, Cronbach alpha test and in-cluster correlation test were used. SPSS software version 18 was used for analysis of the data.

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Result: The mean age of the participants was 30.8 years (SD=4.9) and the average of job tenure in fire-fighting office was 7.4 years (SD=4.8). In order to reliability analyze the questionnaire, Cronbach alpha coefficient of all influential factors was obtained more than 0.7. In-cluster correlation coefficient of the questionnaire is calculated using retesting on all influential factors. With the exception of Physical Environment and Mental Demands which were about average, all other coefficients were over 0.7, which is a very appropriate result.

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Conclusion: Considering that Validity and Reliability factors of the questionnaire were be appropriate, it can be recommended that NIOSH Generic Job Stress Questionnaire (GJSQ) can be used as a Valid and Reliable questionnaire for job stress evaluation in Iran.

Introduction: Pollutants in gas turbine air intake can cause erosion ،corrosion، fouling as well as reduction of power and efficiency of turbine and noticeable economic losses. In order to select the appropriate filtration system, air monitoring of turbine inlet and its filtration is essential. Therefore, this study was performed to assess the quality of gas turbines inlets in a gas power plant in Tehran.

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Material and Method: In this cross- sectional study, the concentration of particulates contained in air intake of 4 types of gas turbines, including: Fiat, Assec, Hitachi and mitsubishi were evaluated in second-half of spring season. For this means, 12 series of air samples were collected using 8 stages cascade Impactor, model AN -200 made by OGAWA company on cellulose – ester filters . The dust concentrations were determined gravimetrically in different ranges of sizes . Then the concentrations of 8 metals including Sodium, Potassiumu Lead, Mercury, Aluminum ,Copper and Cadmium were measured using ,Atomic Absorption Spectroscopy method and the data were statistically analyzed by SPSS Software, version16.

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Results: The results showed that the mean of particulate concentration with the diameter less than 4.7 µ were 64% ,66% ,60% ,67% for Fiat, Assec, Hitachi, mitsubishi respectively and it was 64.25% totally. The concentrations of all assessed metals in particulates less than 4.7 µ were greater than of larger than 5 µ. There were not any differences between particulate concentration in the inlet of Fiat and Hitachi (P>0.05), while in the case of other gas turbine intakes , there were statistically significant differences (P<0.05).

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Conclusion: Based on mass distribution of particles, the highest concentration belongs to particles with diameter of less than 4.7 µ. These particles could damage turbine blades, especially due to the presence of sodium and potassium as corrosive elements in this range (200 µg/m3). Therefore,this range of particle size must be considered in selecting the air intake filtration system.

Introduction: Possible contamination in nuclear medicine centers, in addition to health problems, affect the tests and much effort and cost is required for decontamination. Given the effects of ionizing radiation on human health, rules and regulations have been enacted to avoid contamination, that in working with radioactive materials should be followed to minimize them.

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Material and Method: After mapping of nuclear medicine centers in the province, areas that should be studied for measuring the amount of radioactive contamination were determined. The site selection for the tests were based on the area in which the possibility of further contamination were existance. After measuring the background count rate the radioactive contamination in studied areas were performed using Wipe Test.

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Result: The mean level of background contamination in centers 1, 2 and 3 were 1.75±0.150 μCi, 4.43±0.615 μCi and 2.47±0.055 μCi, respectively. In center 1, only region of Hood pollution was much higher than the permissible limit. In center 2, radioactive contamination of the waiting room, patient rooms, warehouse radiotracer, control room, hood, desk and floor center was exceeded. Also, in center 3, contamination of the doorway, hallway patients, control room, hood, desk, sink, cabinets, room and floor imaging injection (control), respectively, were higher than the permissible limits.

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Conclusion: In centers 1 and 2, most of the radioactive contamination occurred under the hood due to labeling of radiopharmaceuticals activity. Also, in center 3, the highest contamination rate belonged to patients’ corridor that could be due to frequent the area. According to this subject, necessary measures in this regard should be considered by the department responsible for health physics.

Introduction: Noise is one of hazardous agents of workplaces in industries. Electric industries and power plants are among industries in which noise pollution should be taken into account. This study aimed to develop and verify a statistical model for acoustic wave propagation in an indoor environment for noise related risk reduction management.

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Material and Method: This theoretical-experimental study was performed in a gas power plant with nominal capacity of 648 MW including four gas turbine with nominal capacity of 162 MW. The relations between sound power level and sound pressure level in indoor environments were used for developing the statistical model. Moreover, verification of the obtained data was done by a field inside a turbine hall study using ISO9612 standard method.

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Result: Comparison of results from the field and the theoretical study showed no significant differences. The differences between predicted value and field measurements was, in average, less than 0.5 db. This shows the acceptable accuracy of the presented model in estimating the workplace noise level, according to the real functional conditions of the noise sources.

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Conclusion: The presented model is easy and practical and allows managers to model scenarios of noise pollution reduction in indoor environments, before huge expenses of actual control measures. This method is faster comparing to numerical modeling methods. Furthermore, its accuracy is also acceptable.