Effect of TiO2/GAC and water vapor on chloroform decomposition in a hybrid plasma-catalytic system.

This paper presents the combination of TiO2/GAC catalyst and NTP for the decomposition of chloroform using a DBD reactor. The experiments were performed using an AC transformer as the power supply system to determine the optimal conditions of the chloroform conversion in the presence of a hydrogen-rich substance, that is, water vapor. TiO2/GAC enhanced the removal efficiency and also CO2 selectivity significantly, leading to an acceptable conversion rate at SIEs higher than 400 J L-1. The adsorption property of GAC was noticed to be an effective factor for catalytic activity by increasing the residence time, although the higher retention time prevented the accurate determination of chlorine and carbon balance. Selectivity toward HCl was improved considerably from 24.3% to 64.3% over catalyst when water was fed as a hydrogen-rich compound. At the same time, the harmful chlorinated by-products such as TCBA and TCE declined significantly. A noticeable enhancement in the selectivity toward CO2 was observed when both catalyst and water were introduced, regardless of the inlet concentration. Our findings suggest that the hybrid of NTP with TiO2/GAC will highly be effective in the abatement of chloroform, and the addition of H2O will successfully decline harmful chlorinated by-products.

Prediction Effects of Personal, Psychosocial, and Occupational Risk Factors on Low Back Pain Severity Using Artificial Neural Networks Approach in Industrial Workers.

OBJECTIVES: This study aimed to provide an empirical model of predicting low back pain (LBP) by considering the occupational, personal, and psychological risk factor interactions in workers population employed in industrial units using an artificial neural networks approach. METHODS: A total of 92 workers with LBP as the case group and 68 healthy workers as a control group were selected in various industrial units with similar occupational conditions. The demographic information and personal, occupational, and psychosocial factors of the participants were collected via interview, related questionnaires, consultation with occupational medicine, and also the Rapid Entire Body Assessment worksheet and National Aeronautics and Space Administration Task Load Index software. Then, 16 risk factors for LBP were used as input variables to develop the prediction model. Networks with various multilayered structures were developed using MATLAB. RESULTS: The developed neural networks with 1 hidden layer and 26 neurons had the least error of classification in both training and testing phases. The mean of classification accuracy of the developed neural networks for the testing and training phase data were about 88% and 96%, respectively. In addition, the mean of classification accuracy of both training and testing data was 92%, indicating much better results compared with other methods. CONCLUSION: It appears that the prediction model using the neural network approach is more accurate compared with other applied methods. Because occupational LBP is usually untreatable, the results of prediction may be suitable for developing preventive strategies and corrective interventions.

The association between insomnia and cardiovascular risk factors in bus drivers in Iran.

BACKGROUND: Road accidents are one of the most important issues in Iran which more than eighteen thousand persons are died annually because of this problem. Among the major reasons for this issue, sleepiness and cardiovascular disorder can be mentioned. OBJECTIVE: To investigate the association between insomnia and cardiovascular risk factors among professional drivers who are at high risk during driving. METHODS: A total of 1232 male bus drivers were included in the study and two different kinds of data sets were collected: (1) Sleep disorder information using Athens Insomnia Scale (AIS) and (2) Cardiovascular parameters such as systematic measurement of blood pressure, electrocardiography (ECG), total cholesterol, and triglyceride. RESULTS: Our study demonstrated that the prevalence of insomnia in professional bus drivers was 8 percent. The study showed significant association between age, diastolic hypertension and work experience with final awakening earlier than desired (P < 0.05), the rate of the triglyceride level and total sleep duration (p = 0.02), and BMI and sleepiness during the day (P < 0.05). CONCLUSIONS: Our study suggested that elevated serum triglyceride levels and increased diastolic blood pressure may be associated with some sleep complaints in drivers.

Subjective Mental Workload and Its Correlation With Musculoskeletal Disorders in Bank Staff.

OBJECTIVE: The purpose of this study was to evaluate the rate of subjective mental workload (SMWL) and its correlation with musculoskeletal disorders among bank staff members in Kurdistan Province located in western Iran. METHODS: This cross-sectional study was conducted among 200 bank staff members in Kurdistan Province, Iran. The mental workload was assessed using the National Aeronautics and Space Administration-Task Load Index (NASA-TLX) computerized version. NASA-TLX is a multidimensional rating procedure that derives an overall workload score based on a weighted average of ratings on 6 subscales. These subscales include Mental Demands, Physical Demands, Temporal Demands, Performance, Effort, Effectiveness, and Frustration. The musculoskeletal disorders (MSDs) were documented with the Nordic Musculoskeletal Questionnaire and generic body diagram. RESULTS: Of the staff members, 78.5% experienced pain at least once during the past year in 1 of their 9 musculoskeletal body regions. The highest frequencies of pain were in the neck and lower back. The NASA-TLX estimated the Effort and Performance scales with mean ± SD of 72.8 ± 25.2 and 36 ± 22.6, respectively, as the maximal and minimal scores among the 6 subscales of SMWL. The statistical analysis of the data revealed that there was a significant correlation between the overall mental workload score and also among the 6 subscales of SMWL separately with MSDs (P < .05). CONCLUSION: SMWL appears to be a risk factor in the incidence of MSDs, so that the odds of MSDs increased by 11% with each additional 1-point increase in SMWL score.

Visual Display Terminal use in Iranian bank tellers: Effects on job stress and insomnia.

BACKGROUND: Visual Display Terminals (VDTs) are equipments in many workplaces which their use may increase the risk of visual, musculoskeletal and mental problems including insomnia. OBJECTIVE: To determine the relationship between duration of daily VDT use and insomnia among the Iranian bank tellers. METHODS: We randomly selected 382 bank tellers working with VDT. Quality of sleep and stress information were collected by Athens Insomnia Scales (AIS) and Demand-Control Model (DCM) model respectively. RESULTS: Out of 382 participants, 127 (33.2%) had sleep complaints and 255 (66.8%) had no sleep disorders. Moreover, the insomnia symptoms' score were significantly high in the participants having more than 6 hours of daily VDT use after adjusting for multiple confounding factors (P <  0.001). There was no significant relationship between stress and insomnia. CONCLUSIONS: It seems that the low levels of stress and job satisfaction reduce the impact of VDT on sleep quality in tellers who worked less than 6 hours per day.

The efficacy of radiant heat controls on workers' heat stress around the blast furnace of a steel industry.

BACKGROUND: Workers' exposure to excessive heat in molten industries is mainly due to radiant heat from hot sources. OBJECTIVE: The aim of this study was to evaluate the efficacy of radiant heat controls on workers heat stress around a typical blast furnace. METHODS: Two main interventions were applied for reducing radiant heat around the blast furnace of a steel industry located in western Iran. These included using a heat absorbing system in the furnace body and installing reflective aluminum barrier in the main workstation. Heat stress indexes were measured before and after each intervention using the digital WBGT-meter. RESULTS: The results showed MRT and WBGT indexes decreased by 20 °C and 3.9 °C, respectively after using heat absorbing system and also decreased by 18.6 °C and 2.5 °C, respectively after installing a reflective barrier. These indexes decrease by 26.5 °C and 5.2 °C, respectively due to the simultaneous application of the two interventions which were statistically significant (p < 0.001). The core body temperature of workers decreased by 2.6 °C after the application of interventions which was also significant (p < 0.05). CONCLUSIONS: The results confirmed heat control at source can be considered as a first solution for reducing radiant heat of blast furnaces. However, the simultaneous application of interventions could noticeably reduce worker heat stress. The results provide reliable information in order to implement the effective heat controls in typical hot steel industries.

Photocatalytic reduction of hexavalent chromium with illuminated amorphous FeOOH.

In this study, photocatalytic reduction of hexavalent chromium [Cr(VI)] by amorphous FeOOH was investigated with variations in FeOOH dosage, pH, initial Cr(VI) concentration, purging gas, organic compounds and initial hydrogen peroxide concentration. Reduction and adsorption were identified as important processes for the removal of Cr(VI). FeOOH dosage was also an important parameter for the removal of Cr(VI). As the FeOOH dosage increased up to 0.5 g/L, the removal of Cr(VI) was continuously enhanced and then decreased above 0.5 g/L due to increased blockage of the incident UV light. The removal efficiency of Cr(VI) decreased with increasing pH, initial Cr(VI) concentration and initial hydrogen peroxide concentration. While the removal efficiency of Cr(VI) increased with purging of nitrogen gas compared to that of oxygen gas because of less competition between dissolved oxygen and Cr(VI) with the electron in the conduction band of FeOOH. The photocatalytic reduction of Cr(VI) was increased in the presence of citric acid and phenol, while it was decreased in the presence of EDTA and oxalic acid. The reaction rate constant (kobs) was decreased from 0.2141 to 0.0026 1/min and the value of electrical energy per order (EEo) was increased from 22.41 to 1846.15 (kWh/m3) with increasing initial Cr(VI) concentration from 10 to 50 mg/L, respectively. Finally, proper photocatalytic activity was maintained even after five successive cycles.

An intervention for noise control of blast furnace in steel industry.

BACKGROUND: Noise pollution is currently a major health risk factor for workers in industries. The aim of this study was to investigate noise pollution and implement a control intervention plan for blast furnace in a steel industry. METHODS: The measurement of sound pressure level (SPL) along with frequency analysis was done with the sound-level-meter Cell-450. Personal noise exposure was performed using dosimeter TES-1345 calibrated with CEL-282. Before planning noise controls, acoustic insulation properties of the furnace control unit and workers' rest room were assessed. Control room and workers' rest room were redesigned in order to improve acoustical condition. RESULTS: The SPL before intervention around the Blast Furnace was 90.3 dB (L) and its dominant frequency was 4000 Hz. Besides, noise transmission loss of the control and rest rooms were 10.3 dB and 4.2 dB, respectively. After intervention, noise reduction rates in the control and rest rooms were 27.4 dB and 27.7 dB, respectively. The workers' noise dose before and after the intervention was 240% and less than 100%, respectively. CONCLUSIONS: Improvement the workroom acoustic conditions through noise insulation can be considered effective method for preventing workers exposure to harmful noise.

Association between the high risk occupations and bladder cancer in Iran: a case-control study.

OBJECTIVES: The objective of this work was to identify the high-risk occupations in Iran and to re-inspect occupations that were related to bladder cancer. MATERIALS AND METHODS: In the study, 300 patients suffering from bladder cancer and 500 control individuals were interviewed. Demographic information, occupational history, and history of exposure to chemical compounds such as aromatic amines for each participant were collected. ORs and 95% CIs were calculated using unconditional logistic regression for each occupation. RESULTS: There was a significantly increased risk of bladder cancer among truck and bus drivers (OR = 11.3), skilled agricultural, forestry and fishery workers (OR = 6.0), metal industry workers (OR = 6.0), domestic housekeepers (OR = 5.9), and construction workers (OR = 3.8). CONCLUSIONS: The study showed a strong correlation between truck and bus drivers, skilled agricultural, forestry and fishery workers, metal industry workers, domestic housekeepers, as well as construction workers and the increased risk of bladder cancer in these occupations.