Effect of TiO2-ZnO/GAC on by-product distribution of CVOCs decomposition in a NTP-assisted catalysis system

In this study, the catalytic effect of TiO2-ZnO/GAC coupled with non-thermal plasma was investigated on the byproducts distribution of decomposition of chlorinated VOCs in gas streams. The effect of specific input energy, and initial gas composition was examined in a corona discharge reactor energized by a high frequency pulsed power supply. Detected by-products for catalytic NTP at 750 J L-1 included CO, CO2, Cl2, trichloroacetaldehyde, as well as trichlorobenzaldehyde with chloroform feeding, while they were dominated by CO, CO2, and lower abundance of trichlorobenzaldehyde and Cl2 with chlorobenzene introduction. Some of the by-products such as O3, NO, NO2, and COCl2 disappeared totally over TiO2-ZnO/GAC. Furthermore, the amount of heavy products such as trichlorobenzaldehyde decreased significantly in favor of small molecules such as CO, CO2, and Cl2 with the hybrid process. The selectivity towards COx soared up to 77 over the catalyst at 750 J L-1 and 100 ppm of chlorobenzene. © by Farshid Ghorbani-Shahna 2015

A Laboratory Study of Low-Temperature CO Removal from Mobile Exhaust Gas Using In-Plasma Catalysis

The combination of nonthermal plasma (NTP) with catalytic methods has been shown to improve catalyst light-off temperature via reactions among plasma discharge products and by-products. Thus, NTP may improve selectivity, process, and removal efficiency. In this study, NTP was combined with a catalytic film of mixed metal oxides (ceria-zirconia-gamma alumina layer) in the discharge zone to investigate low-temperature CO removal. Three different reactors having identical geometries were used: a plasma reactor, a catalytic reactor, and a hybrid plasma-catalytic reactor. The CO removal efficiency of 36.5 was achieved using hybrid plasma-catalytic reactor at 80 °C with 860 J/lit. The temperature and flow rate were found to have significant impacts (P-value � 0.05), which is unexpected due to the key role of hydroxyl and active radicals induced by plasma discharge. Calculated synergy factor of about 2 signals call for further study on the hybrid properties of catalytic efficiency and plasma physics for optimal CO removal. © 2020, Springer Nature Switzerland AG

The effectiveness of practical and lecture training methods on skill of electric technicians based on TIER model

Background and aims: One of the reasons of electric shocks is failure to provide efficient training to the individual. The aim of this study is to compare the effectiveness of practical and lecture training methods on skill and ability of electrical technicians in recognizing and control electrical hazards by TIER model. Methods: This study is a quasi-experimental (before and after type). First stage, training need assessment was conducted using DACUM model, being immediately followed by the pilot test results a sample of 61 workers of Steam Generator and 61 workers of Electric Generator were randomly selected. In second stage, two performance tests performed separately one month before and after treatment sessions then the validity and reliability of tests were calculated. Then selected intervention methods, 'Hands-on Practice' method for vapor generator personnel and 'Classroom' method for generator personnel, were assigned to the treatment groups within three sessions separately. Results: After education, scores of skill and ability in steam generator staff were 13.10, 15.27 and in generators staff group were 7.24, 11.81. And ability and skills scores in both groups showed significant differences (p< 0.001). Conclusion: Hands-on practice" was more effective than "lecture method" to increase firstaid skills and electrical hazard recognition abilities

Characterization of radio active aerosols in Tehran research reactor containment

The objectives of this research were to determine the levels of radioactivity in the Tehran research reactor containment and to investigate the mass-size distribution, composition, and concentration of radio nuclides during operation of the reactor. A cascade impactor sampler was used to determine the size-activity distributions of radioactive aerosols in each of the sampling stations. Levels of α and β activities were determined based on a counting method using a liquid scintillation counter and smear tests. The total average mass fractions of fine particles (particle diameter dp &lt;1 µm) in all of the sampling stations were approximately 26.75 , with the mean and standard deviation of 52.15 ± 19.75 µg/m3. The total average mass fractions of coarse particles were approximately 73.2, with the mean and standard deviation of 71.34 ± 24.57 µg/m3. In addition to natural radionuclides, artificial radionuclides, such as 24Na,91Sr,131I,133I,103Ru,82Br, and 140La, may be released into the reactor containment structure. Maximum activity was associated with accumulation-mode particles with diameters less than 400 nm. The results obtained from liquid scintillation counting suggested that the mean specific activity of alpha particles in fine and coarse-modes were 89.7 and 10.26 , respectively. The mean specific activity of beta particles in fine and coarse-modes were 81.15 and 18.51 , respectively. A large fraction ofthe radionuclides' mass concentration in the Tehran research reactor containment was associated with coarse-mode particles, in addition, a large fraction of the activity in the aerosol particles was associated with accumulation-mode particles. © 2015, Vinca Inst Nuclear Sci. All rights reserved

The Prevalence of Needle sticks injuries among health care workers at a hospital in Tehran

ABSTRACT Needle stick injuries (NSIs) are one of the most significant and preventable hazards in relation to Healthcare workers (HCWs). Such injuries have been shown to be of high prevalence within developing countries. To determine the prevalence and circumstances pertaining to the occurrence of NSIs among HCWs employed at a special hospital. The study conducted was a cross-sectional study on HCWs and was carried out in one of Tehran's special hospitals in the year 2012. In this study, in order to identify and determine hazardous potential due to needle stick, HFMEA method was chosen. This resulted in the collection of 240 valid and reliable questionnaires. The validity and reliable nature of the questionnaires was confirmed by experts and by means of the test re-test method. The gathered data was analyzed with SPSS software, version 16.From the analysis of the data it was shown that, a total of 97 (40.42%) HCWs had suffered NSIs in the last year. The patient ward showed the highest prevalence of NSIs (47.42%) in the hospital. Nurses had the highest risk of suffering NSIs (56.7%) in comparison with the other occupational groups. All in all 175 NSIs occurred for the 240 HCWs trialed during the selected period of clinical practice. Of those that received injuries, only roughly 1 in 3 (38.14%) reported it to their infection control officer. Just over a quarter (26.80%) of the injured HCWs used post exposure prophylaxis (PEP) against HIV. Almost all (88.75%) of the HCWs had received a safe injection course. In general, NSIs and their subsequent underreporting are commonplace among hospital healthcare professionals. Significantly, more than two-thirds of the injured HCWs did not use post-exposure prophylaxis (PEP) against HIV. Improved prevention and reporting strategies are needed if the occupational health and safety of healthcare workers is to improve

Elimination of carbon monoxide using non-thermal plasma

Background and aims: Non-thermal plasma is considered as a successful new technology with high efficiency in the air pollution control. Various types of atmospheric pollutants adversely influence on the human health and the environment regionally and globally. Carbon monoxide has been introduced as a critical pollutant which can cause the environmental and health effects. The growing concerns about effects of air pollution on human health, and also more stringent strategies of choosing the air quality standards, have motivated the development of air pollution control techniques, particularly the non-thermal plasmas techniques. Therefore, the aim of this study is the removal of the carbon monoxide (CO) contaminants in the dry air and argon atmospheres in order to determine of the effective parameters. Methods: The current study has determined the effects of temperature, the CO concentration, the voltage and the residence time on the CO elimination efficiency by ASTM D 5835 method in the system of negative plasma reactor (diluted by dry air) and the system of positive plasma reactor (diluted by argon gas), simultaneously. Results: The results indicated that the temperature and the residence time did not have a significant effect on the CO removal in the both dry air and argon gas systems. However, the most important variable in the both systems was the voltage in the vicinity of 8 kilovolts with the p<0.05 and the mean effect of 37 and 13.2 in the dry air and argon gas systems, respectively. Conclusion: The results of CO elimination in the dry air and argon atmosphere indicate that the dry air system, due to present of the oxygen active ions, has better performance compared to the argon gas system

Prioritizing occupational safety and health indexes based on the multi criteria decision making in construction industries

Background and aims: Critical infrastructures are the most important sectors in nation security, public safety, socioeconomic security and environment in the world. Such incidents make people, environment and industries harmed. The occurrence of accidents is common in the basic infrastructure of all countries in the world. Building industry is inherently facing many problems and ambiguities. Events' rate of construction industry and other industries in Iran is higher than other parts of the world. The aim of this research is prioritization of indicators of health and safety in the small and large construction industry. Methods: Indexes are considered as the main body of the risk management system for all areas of activity. At first, the indicators were selected by experts from a list of detailed performance indicators, Then, these indicators according to key indicators of evaluating the performance of health and safety in the construction industry were weighted and finally ranked and modeled with the SMART (Specific, Measurable, Achievable, Realistic Timeable) criteria, using fuzzy TOPSIS method. Results: The results obtained from the analysis of fuzzy-TOPSIS based on determining the priority of safety-health indicators in both small and large groups of buildings, represented a different range of the 28-fold indicators priority. Safety of adjacent structures and using of PPE in small buildings up to six floors, had the high close rate, while the noise, safety scaffolding, excavation and trucks for reasons of height and vertical spread of structures in the large and over 6 floors buildings had the important priorities. Conclusion: Prioritizing safety and health indicators based on Fuzzy TOPSIS method with SMART criteria can be applied as a method of professionals' health assessment in the engineering field

Prioritizing occupational safety and health indexes based on the multi criteria decision making in construction industries

Background and aims: Critical infrastructures are the most important sectors in nation security, public safety, socioeconomic security and environment in the world. Such incidents make people, environment and industries harmed. The occurrence of accidents is common in the basic infrastructure of all countries in the world. Building industry is inherently facing many problems and ambiguities. Events' rate of construction industry and other industries in Iran is higher than other parts of the world. The aim of this research is prioritization of indicators of health and safety in the small and large construction industry. Methods: Indexes are considered as the main body of the risk management system for all areas of activity. At first, the indicators were selected by experts from a list of detailed performance indicators, Then, these indicators according to key indicators of evaluating the performance of health and safety in the construction industry were weighted and finally ranked and modeled with the SMART (Specific, Measurable, Achievable, Realistic Timeable) criteria, using fuzzy TOPSIS method. Results: The results obtained from the analysis of fuzzy-TOPSIS based on determining the priority of safety-health indicators in both small and large groups of buildings, represented a different range of the 28-fold indicators priority. Safety of adjacent structures and using of PPE in small buildings up to six floors, had the high close rate, while the noise, safety scaffolding, excavation and trucks for reasons of height and vertical spread of structures in the large and over 6 floors buildings had the important priorities. Conclusion: Prioritizing safety and health indicators based on Fuzzy TOPSIS method with SMART criteria can be applied as a method of professionals' health assessment in the engineering field

Design and evaluation of the performance of local exhaust hood on the welding torch

Background and aims: Threats against welders' health due to exposure to welding fume is an important issue; thus, controlling and examining effective exhaust of fumes are necesary. In this study, was evaluated prototype operation of local exhaust ventilation on-gun in bench scale. Methods: Duct velocity average was determined using traverse points method and calculated flow rate by hood using ACGIH standard method. Also capture velocity close in contaminant source (Arc Point) was measured using thermal anemometer. Then, in order to determine total particles concentration and capture efficiency created by system NIOSH 7200 standard method was used. Results: Duct velocity average and created flow rate by evaluated system were 6296.1±92.50 fpm and 34.06±0/50 scfm, respectively. Also, capture velocity in close of the weld point was obtained 140 fpm. Sampling results for averaged total particles concentration in off and on positions of system were 75±7 mg/m3 and 16.7±4 mg/m3, respectively. As a result, 77 containment efficiency was achieved by this system. Conclusion: The local exhaust ventilation used in this study was a low cost prototype and according to the acheived results, it leads to reduce total particles concentration (T.P) in breathing zone aproximately to 22

The Role of the Implementation of National Building Regulations in the Fire Safety Improvement of Industrial Structures

In accordance with national building regulations, human safety and health should not be compromised in any way by the structures. Noncompliance with existing standards can increase the risk of fire in buildings. This study aimed to assess the impact of national building regulations on the reduction of the fire risk level in an industrial structure. In this study, the fire risk level of the building and contents, occupants, and activities were calculated in a power plant control room using Fire Risk Assessment Method for Engineering (FRAME). In the following, by assessing the existing situation, the effect of the implementation of national building regulations was determined on the reduction of fire risk level. The result showed that the fire risk level for occupants (20.64), building and content (1.02) that are above the acceptable level and corrective measures and design changes should be applied to reduce the risk level. Also, in case of application of the third chapter of Iranian National Building Regulations in power plant construction, the fire risk level will be reduced by 11.7% compared to the existing situation This study showed that the implementation of national building standards and regulation can provide the occupants life safety by correctly predicting escape routes. Fire Risk Assessment Method for Engineering (FRAME) is a very effective tool for selecting the best control strategies for fire safety of industrial structures