Assessment of workers' exposure to hand-arm and whole body vibration in one of the furniture industries in east of Tehran

Workers in wood industry are exposed to vibration and its damages. The purpose of this study was to evaluate exposure to hand-arm and whole body vibration in the wood industry. In this study, the parameters of whole body and hand-arm vibrations such as effective acceleration, overall equivalent acceleration, Vibration Dose Value and crest factor were studied on two Thicknessing planes, two sliding panel saw machines, two orbital sander, and three operators of perforate procedure. Assessments were done by the use of an oscillator and an analyzer of Svantak Co. Evaluating Hand-arm and whole body vibrations were conducted based on ISO 5349-1, ISO 5349-2 and ISO 2631-1 standards, respectively, and the findings/ the evaluated data were analyzed. The mean amount of daily exposure to hand-arm vibration (RMS) in Thicknessing plane, Orbital Sander and Sliding panel saw machine operators are respectively 5.56, 5.49 and 3.37 m/s2 . In addition, the average crest factor of the 3 jobs is higher than 6. Mean of daily Exposure to whole body vibration in 3 machine operators of Thicknessing plane, perforate procedure and Sliding panel saw is respectively, 0.28, 0.24 and 0.17 meters per square second. The crest factor for all the exposures was to be less than 6 and the mean of the calculated daily vibration dose equaled 5.83 with the standard deviation of 0.87( m)⁄s^1.75 . In further measured situations, exposure to hand-arm vibration is more than the standard level, so engineering and management measures are required to reduce the amount of exposure and support the health of the operators and the equipment

Humic Acid Degradation via Solar Photo-Fenton Process in Aqueous Environment

Control of mutagenic and carcinogenic disinfection by-products, particularly Trihalomethanes (THMs) and Halo Acetic Acids (HAAs) in water treatment process is critical, due to their adverse effects on human health. Generally, reducing the toxicity of these by-products hinges on prior removal of the precursor materials, such as Humic Acid (HA) in drinking water. This study was conducted to investigate the role of some parameters that could affect the removal of HA, including HA (5 and 10 ppm) and H2O2 (20, 40, 60, and 80 ppm) initial concentrations, Iron (II), sulfate heptahydrate dosage (4, 8, 12, and 16 ppm), pH (2, 3, 4 and 5), Oxidation time (5, 10, 15 and 30 min), and Sunlight levels (322±13 kWm-2). To accelerate the process of HA removal, the Solar Photo-Fenton (SPF) process was employed by direct irradiation of converged sunlight in a Parabolic Trough Collectors (PTC), with 3m2 effective area. HA levels were measured via quantifying Dissolved Organic Carbon (DOC) concentrations by means of a TOC Analyzer method. The results showed that the SPF process is under control of the Fe & H2O2 ratio, the Fe2+ dosage and especially the pH quantity. In optimal condition, (pH: 4, oxidation time: 30min, initial HA levels: 50 ppm, H2O2 concentrations: 20 ppm Fe+2 levels: 4 ppm), the study found more than 98% DOC removal. In conclusion, the SPF, as an economically effective technique, could be applied for the removal of HA in aqueous environments

Assessment of Metro Passengers’ Convenience While Sitting and Standing in Confrontation with Whole-Body Vibration

Nowadays, using public transportation vehicles like metro in large cities are of significance, and exposure to whole-body vibration for the metro passengers is one of the physical contaminations. This paper is conducted with the aim of evaluating the passengers’ convenience and health both in sitting and standing conditions. The present study was done on the passengers of lines 1, 2, and 4 of Tehran metro with the use of an oscillator and a SVAN958 analyzer of SVSNTEK Co., based on the measurement methods and guidelines of ISO 2631-1, 4. The average amounts of RMS acceleration while sitting was 1.1 m/s2  with the standard deviation of 0.14 and while standing was 0.91 m/s2  with the standard deviation of 0.05; estimated VDV amount while sitting and standing equaled 6.72 m/s2  with the standard deviation of 1.26 and 6.48 m/s1.75 with the standard deviation of 0.96. Calculated RMS amounts generally fluctuated between level 3 (fairly unpleasant) and level 4 (unpleasant) of convenience evaluation scale, and total calculated VDV amounts for the sitting passengers was 1.1 m/s1.75 , being more than the perceived dose of standing passengers

Predicting health risks of exposure to whole body vibration in the urban taxi drivers

Introduction: Limited studies have been done to evaluate the whole-body vibration (WBV) exposure experienced by Taxi drivers. Therefore, the aim of this study was to evaluate the exposure to whole body vibration and repeated shocks in urban taxi drivers and also to compare different methods of evaluation in this job environment. Material and Method: Measurement and evaluation process were conducted in accordance with procedure of the ISO 2631-1 and ISO 2631-5 standards. The measurements were done by SVAN 958 Sound and Vibration Analyzer and using tri-axial accelerometer centered on the contact surface between the seat and the driver in 9 taxis.   Result: The measurements done according to ISO 2631-1 method showed greater risk compared to Daily Equivalent Static Compression Dose, Sed, presented in ISO 2631-5. Calculated daily exposure durations for exposure action level in root-mean square, vibration dose value, and daily equivalent static compressive stress methods were 4.55, 3.54 and 31.70 hours, respectively. Conclusion: The large differences in estimated exposure durations of action limits and permissible limits resulted by different methods reflect the inconsistency of the selected evaluation methods. Therefore, future research is necessary to amend the limits presented in the standard

Humic Acid Degradation via Solar Photo-Fenton Process in Aqueous Environment

Control of mutagenic and carcinogenic disinfection by-products, particularly Trihalomethanes (THMs) and Halo Acetic Acids (HAAs) in water treatment process is critical, due to their adverse effects on human health. Generally, reducing the toxicity of these by-products hinges on prior removal of the precursor materials, such as Humic Acid (HA) in drinking water. This study was conducted to investigate the role of some parameters that could affect the removal of HA, including HA (5 and 10 ppm) and H2O2 (20, 40, 60, and 80 ppm) initial concentrations, Iron (II), sulfate heptahydrate dosage (4, 8, 12, and 16 ppm), pH (2, 3, 4 and 5), Oxidation time (5, 10, 15 and 30 min), and Sunlight levels (322±13 kWm-2). To accelerate the process of HA removal, the Solar Photo-Fenton (SPF) process was employed by direct irradiation of converged sunlight in a Parabolic Trough Collectors (PTC), with 3m2 effective area. HA levels were measured via quantifying Dissolved Organic Carbon (DOC) concentrations by means of a TOC Analyzer method. The results showed that the SPF process is under control of the Fe & H2O2 ratio, the Fe2+ dosage and especially the pH quantity. In optimal condition, (pH: 4, oxidation time: 30min, initial HA levels: 50 ppm, H2O2 concentrations: 20 ppm Fe+2 levels: 4 ppm), the study found more than 98% DOC removal. In conclusion, the SPF, as an economically effective technique, could be applied for the removal of HA in aqueous environments

Assessment of workers' exposure to hand-arm and whole body vibration in one of the furniture industries in east of Tehran

Workers in wood industry are exposed to vibration and its damages. The purpose of this study was to evaluate exposure to hand-arm and whole body vibration in the wood industry. In this study, the parameters of whole body and hand-arm vibrations such as effective acceleration, overall equivalent acceleration, Vibration Dose Value and crest factor were studied on two Thicknessing planes, two sliding panel saw machines, two orbital sander, and three operators of perforate procedure. Assessments were done by the use of an oscillator and an analyzer of Svantak Co. Evaluating Hand-arm and whole body vibrations were conducted based on ISO 5349-1, ISO 5349-2 and ISO 2631-1 standards, respectively, and the findings/ the evaluated data were analyzed. The mean amount of daily exposure to hand-arm vibration (RMS) in Thicknessing plane, Orbital Sander and Sliding panel saw machine operators are respectively 5.56, 5.49 and 3.37 m/s2 . In addition, the average crest factor of the 3 jobs is higher than 6. Mean of daily Exposure to whole body vibration in 3 machine operators of Thicknessing plane, perforate procedure and Sliding panel saw is respectively, 0.28, 0.24 and 0.17 meters per square second. The crest factor for all the exposures was to be less than 6 and the mean of the calculated daily vibration dose equaled 5.83 with the standard deviation of 0.87( m)⁄s^1.75 . In further measured situations, exposure to hand-arm vibration is more than the standard level, so engineering and management measures are required to reduce the amount of exposure and support the health of the operators and the equipment