Dynamic risk assessment of storage tank using consequence modeling and fuzzy Bayesian network.

Accidents in process industries cause irreparable economic, human, financial and environmental losses annually. Accident assessment and analysis using modern risk assessment methods is a necessity for preventing these accidents. This study was conducted with the aim of Dynamic risk assessment of tank storage using modern methods and comparing them with traditional method. In this study, bow tie (BT) method was used to analyze the Leakage event and its consequences and model the cause of the outcome, and the Bayesian network method was used to update the probability rate of the consequences. Then, four release scenarios were used. Possible selection and release outcome were modeled using version 5.4 of ALOHA software. Finally, according to the degree of reproducibility of possible consequences and risk number modeling for the four scenarios were estimated. The results of modeling the cause and effect showed that 50 Basic events are effective in chemical leakage and Pool fire is the most probable consequence due to chemical leakage in both BT and Bayesian network (BN) models. Also, the modeling results showed that Leakage 50 mm diameter has the highest Emission rate (80 kg/min) and Leakage of 1 mm have the lowest emission rate. The results of risk assessment showed that the estimated risk number in both models is in the unacceptable range. In this study, an integrated approach including BT, Fuzzy Bayesian networks and consequence modeling was used to estimate the risk in tank storage. The use of these three approaches makes the results of risk assessment more objective than conventional methods. The results of outcome modeling can be used as a guide in adopting accident prevention and emergency preparedness approaches.

Risk Assessment of Silicosis and Lung Cancer Mortality associated with Occupational Exposure to Crystalline Silica in Iran.

BACKGROUND: Exposure to crystalline silica has long been identified to be associated with lung diseases. Therefore, the present study aimed to assess the risk of silicosis and lung cancer associated with occupational exposure to crystalline silica in Iran. STUDY DESIGN: It is a systematic review study. METHODS: Different databases were searched, and the Cochrane method was used for the systematic review. Thereafter, cumulative exposure to crystalline silica (mg/m3-y) was calculated in every industry. The relative risk of death from silicosis was performed using Mannetje's method. Based on the geometric mean of exposure, the lung cancer risk of exposure to crystalline silica was also calculated. RESULTS: As evidenced by the results, worker's exposure to silica ranged from a geometric mean of 0.0212- 0.2689 mg/m3 (Recommended standard by the American Conference of Governmental Industrial Hygienists (ACGIH) was 0.025 mg/m3), which is generally higher than the occupational exposure limit recommended by National Institute for Occupational Safety and Health (NIOSH), ACGIH, and occupational exposure limits. The relative risk of silicosis was in the range of 1 to 14 per 1000 people, and the risk of lung cancer in workers ranged from 13-137 per 1000 people. CONCLUSION: Since workers are at considerable risk of cancer due to exposure to silica in Iran, exposure control programs need to be implemented in workplaces to decrease the concentration of silica.

Modeling important factors on occupational accident severity factor in the construction industry using a combination of artificial neural network and genetic algorithm.

BACKGROUND: Many occupational accidents annually occur worldwide. The construction industry injury is greater than the average injury to other industries. The severity of occupational accidents and the resulting injuries in these industries is very high and severe and several factors are involved in their occurrence. OBJECTIVE: Modeling important factors on occupational accident severity factor in the construction industry using a combination of artificial neural network and genetic algorithm. METHODS: In this study, occupational accidents were analyzed and modeled during five years at construction sites of 5 major projects affiliated with a gas turbine manufacturing company based on census sampling. 712 accidents with all the studied variables were selected for the study. The process was implemented in MATLAB software version 2018a using combined artificial neural network and genetic algorithm. Additional information was also collected through checklists and interviews. RESULTS: Mean and standard deviation of accident severity rate (ASR) were obtained 283.08±102.55 days. The structure of the model is 21, 42, 42, 2, indicating that the model consists of 21 inputs (selected feature), 42 neurons in the first hidden layer, 42 neurons in the second hidden layer, and 2 output neurons. The two methods of genetic algorithm and artificial neural network showed that the severity rate of accidents and occupational injuries in this industry follows a systemic flow and has different causes. CONCLUSION: The model created based on the selected parameters is able to predict the accident occurrence based on working conditions, which can help decision makers in developing preventive strategies.

Effect of anthropometric and demographic factors on musculoskeletal disorders in nurses' aides.

BACKGROUND: Nurses' aides usually face various stressors, making them prone to musculoskeletal disorders (MSDs). OBJECTIVE: This study evaluates the effect of ergonomic and anthropometric indices, postural risk, and demographic variables on MSDs in nurses' aides. METHODS: Demographic variables, anthropometric dimensions, postural risk level (RL), and related percentiles of 75 nurses' aides were examined using Quick Exposure Check (QEC) software, caliper, and body map questionnaire. Pearson correlation coefficient, univariate and multivariate tests were used to analyze the data. RESULTS: The results showed that the RL of QEC in both groups of males and females was 73.67±22.34 (RL = 4) and 65.34±18.38 (RL = 3), respectively. The level of MSDs in the lumbar, thigh, and leg areas was higher than in other areas. Also, increasing age and work experience, and BMI were significantly associated with increasing disorders in the hands, wrists, and shoulders, respectively (P < 0.05). The results showed that an increase in some anthropometric indices such as body height, buttock, knee, popliteal height, abdomen depth, standing grip access limit, sitting grip access limit increased disorders in the hands and wrists. Also, MSDs were predicted in different areas of the nurses' aides' bodies using regression models, which was significant in the hands, wrists, elbows, legs, and shoulders (P < 0.05). CONCLUSIONS: The results showed that there was a significant difference between male and female nurses in most aspects of anthropometry and the risk level of QEC. Therefore, it is necessary to pay attention to anthropometric dimensions, and demographic diversity to design tools and workstations.

Effect of shift work on working memory, attention and response time in nurses.

Objective. The present study aimed to investigate the relationship between shift work and cognitive performance in nurses. Methods. The present before-after study included 35 female nurses 25-40 years old with similar mental and physical workload. Working memory, response time and attention were assessed using Wechsler and Stroop tests. The variables were measured at the beginning and the end of three working shifts (morning, afternoon and night). An interval of 3 days was considered for performing an after-shift test to eliminate the learning effect. Data were analyzed using repeated-measures analysis of variance (ANOVA). Results. At the end of all three shifts, nurses' working memory (p = 0.039) and interference score (p = 0.04) were significantly decreased, but their response time was not significantly affected during a shift. The decrease in working memory after the night shift was significantly higher than after the morning and evening shifts (p < 0.001). Conclusion. The results of this study showed that shift work can affect some aspects of cognitive function (working memory and attention) in nurses, and this effect was more prominent after a night shift.

Developing a safety audit checklist for in-operation administrative buildings.

BACKGROUND: The structure of buildings is in degradation over time, monitoring their safety status and providing timely warnings is crucial. Therefore, an efficient visual inspection of the building's safety has intrinsic value to give early warnings to owners and managers. OBJECTIVE: This study aimed to provide an audit tool for evaluation of the administrative in-operation buildings' safety status. METHODS: Factors affecting the administrative buildings' safety status was determined based on the National Building Regulations of Iran (NBRI) and other studies. Checklist items and their guidelines were prepared. Face validity (quantitative and qualitative), Content Validity Ratio (CVR), and Content Validity Index (CVI) were calculated for the checklist. The Intra-class Correlation Coefficient (ICC) used for inter-rater reliability and Cronbach's α was used to evaluate internal consistency of the checklist. RESULTS: Forty-seven items related to in-operation building safety were extracted from literature review. Based on the results of the psychometric analysis, 5 items were removed and 42 items remained. The values of different psychometric indices for the other items indicated their acceptable validity (α= 0.82, ICC≥0.75). CONCLUSION: The designed checklist had a good level of validity and reliability for inspecting architectural, technical services, and managerial safety aspects of administrative in-operation buildings. Stakeholders can use it for quick and comprehensive assessment of building safety. Use of this checklist are expected to give early warnings about the safety of buildings to the stakeholders.

The effects of combined exposure to road traffic noise and whole body vibration on types of attention among men.

BACKGROUND: Noise and vibration are considered as harmful physical agents in the environment which have adverse effects on cognitive performance. One of the occupations at risk is driving, where there is a possibility of simultaneous exposure to road traffic noise and whole body vibration (WBV) transferred through the vehicle. This study aims to assess the effects of single and combined exposure to road traffic noise and WBV on different types of attention in men. METHODS: The experiment was conducted on 24 men in 4 steps, executed on each participant inside an acoustic room. After recording a number of various attention scores at background conditions (27 dBA noise, no vibration) the participants were given single and combined exposure to noise levels at 55 and 85 dBA and vibration frequencies of 0.65 and 0.95 m/s2. RESULTS: As for combined exposure to noise and vibration, increasing vibration acceleration and noise levels at the same time compared to background condition caused a rise in the score of all visual attention types among groups exposed to low vibration acceleration and those exposed to medium acceleration and low noise. Nevertheless, when noise level and vibration acceleration is increased at the same time compared to background, auditory attention type scores mostly fell among groups with similar vibration accelerations. CONCLUSIONS: Overall, single and combined exposure to environmental stressors under investigation had a predominantly negative effect on auditory attention while the effects on visual attention were inconclusive. Definitive conclusions however require further systematic and comprehensive experiments.

The effects of combined exposure to noise and heat on human salivary cortisol and blood pressure.

Purpose. Noise and heat are the most important physical hazardous agents that can affect physiological parameters. This study investigated the independent and combined effects of noise and heat exposure on human saliva cortisol and blood pressure. Methods. In this experimental study, 72 students were exposed to noise (at sound pressure levels of 45, 75, 85 and 95 dB(A)) and heat (at wet bulb globe temperatures [WBGTs] of 22, 29 and 34 °C) for 30 min. Samples of saliva and blood pressure were taken before and after each independent and combined exposure. Results. The results revealed that the average saliva cortisol and blood pressure in male and female subjects increased significantly after independent exposure to noise at 95 dB(A) and a WBGT of 34 °C. The combined exposure to noise and heat increased saliva cortisol and blood pressure, which was statistically significant for three combinations of 95 dB(A) at 34 °C, 95 dB(A) at 29 °C and 85 dB(A) at 34 °C. Conclusions. Combined exposure to noise and heat could affect saliva cortisol and blood pressure in both male and female groups. Further studies are recommended to capture other combinations of physical hazardous agents, especially in the field.

The effect of theory-based educational intervention on correct principles of manual material handling among men.

BACKGROUND: Changing human behavior for the purposes of improving the way people work is an integral part of most educational interventions. This study aimed to evaluate the effect of a model based on the theory of planned behavior (TPB) on correct principles of manual material handling (MMH) among male soldiers. SUBJECTS AND METHODS: This study was a quasi-experimental, pretest-posttest research with a control group. Furthermore, 140 soldiers, from an area located in the city of Bandar Abbas, Iran, were selected through a simple random sampling and they were divided into two groups: intervention and control (70 subjects in each group). The data were collected using a three-part questionnaire including demographic information, the theory constructs, and MMH behavior. The intervention group was given the relevant education, and after 2 months, the both groups were evaluated. RESULTS: Based on regression analysis, attitude toward behavior and perceived behavioral control were predictors for correct principles of MMH. There were significant differences between the mean scores of the theory constructs before and after the education in intervention group (P < 0.001); however, no significant differences were observed in the theory constructs in the control group after the intervention. Before the education, the mean score of MMH of the intervention group was 38.30 ± 6.45; but after, the education, this changed into 44.20 ± 6.01, and significantly increased (P < 0.001). CONCLUSIONS: Educational intervention based on the TPB was effective in improving behavior for correct MMH in soldiers. Thus, the use of such educational programs according to the constructs of the planned behavior theory is recommended.

The Effect of Noise Exposure on Cognitive Performance and Brain Activity Patterns.

BACKGROUND: It seems qualitative measurements of subjective reactions are not appropriate indicators to assess the effect of noise on cognitive performance. AIM: In this study, quantitative and combined indicators were applied to study the effect of noise on cognitive performance. MATERIAL AND METHODS: A total of 54 young subjects were included in this experimental study. The participants' mental workload and attention were evaluated under different levels of noise exposure including, background noise, 75, 85 and 95 dBA noise levels. The study subject's EEG signals were recorded for 10 minutes while they were performing the IVA test. The EEG signals were used to estimate the relative power of their brain frequency bands. RESULTS: Results revealed that mental workload and visual/auditory attention is significantly reduced when the participants are exposed to noise at 95 dBA level (P < 0.05). Results also showed that with the rise in noise levels, the relative power of the Alpha band increases while the relative power of the Beta band decreases as compared to background noise. The most prominent change in the relative power of the Alpha and Beta bands occurs in the occipital and frontal regions of the brain respectively. CONCLUSION: The application of new indicators, including brain signal analysis and power spectral density analysis, is strongly recommended in the assessment of cognitive performance during noise exposure. Further studies are suggested regarding the effects of other psychoacoustic parameters such as tonality, noise pitch (treble or bass) at extended exposure levels.