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Showing 6 results for Heidari
Yusef Omidi, Gholamreza Goudarzi, Ali Mirza Heidari , Seyed Mohammad Daryanoosh, Volume 3, Issue 2 (Spring, 2016)
Abstract
Background: Epidemiological studies have illustrated that exposure to atmospheric nitrogen oxides (NO2/NOX) is responsible for an increased risk of acute or chronic diseases such as cancer. In this study the health risks associated with nitrogen dioxide (NO2) were assessed in the city of Kermanshah, the capital of Kermanshah province, Iran.
Methods: Data on hourly NO2 levels that had been measured with the Environ tech model M200 was taken from the Kermanshah Environmental Protection Agency (KEPA). The AirQ2.2.3 model was used to quantify data based on baseline incidence (BI), relative risk (RR), and attributable proportion (AP). The number of cases of cardiovascular mortality (CM), acute myocardial infarction (MI), and hospital admissions for chronic obstructive pulmonary diseases (HACOPD) was estimated.
Results: The results of the current study show that there were 33, 16, and 13 cases of CM, acute MI, and HACOPD, respectively, attributable to NO2 exposure. Furthermore, 26.85% of health impacts occurred on days when NO2 levels did not exceed 40 μg/m3. For every 10 μg/m3 increase in the NO2 level, the risk of CM, MI, and HACOPD rose about 0.2%, 0.36%, and 0.38%, respectively.
Conclusion: In order to reduce the number of cases of mortality and morbidity caused by exposure to NO2, several immediate steps should be taken by the government to control emissions from various sources, particularly car exhaust, to reduce the levels of NO2 in the atmosphere.
Kolsoom Mohammad Moradi, Kavous Dindarloo, Vali Alipour, Mohsen Heidari, Volume 4, Issue 1 (Winter, 2017)
Abstract
Background: Bromide is found naturally in groundwater and surface water. The rapid growth of industrial activities, drainage of surface runoff, and use of methyl bromide in pesticides has increased bromide discharge to the environment. Disinfection of water-containing bromide causes the creation of additional products of organo-halogenated that are considered cancer-causing agents. In this study, the effect and optimization of factors in removal of this ion was evaluated by using the nano-photocatalytic UV/ZnO process.
Methods: This analytical study was conducted in a batch system by the phenol-red method. The test design was performed through the analysis model of multi-factor variance with 99 subjects, while the main, interactive, and reciprocal effects of variables, such as reaction time, catalyst concentration, bromide concentration, and pH at different levels of each factor, were analysed by using SPSS version 16.
Results: The main, interactive, and reciprocal effects of factors were significant in three different levels with P < 0.001, and the optimal level of the factors reaction time, catalyst concentration, bromide concentration, and pH were 120 minutes, 0.5, 0.1, and 7 mg/L, respectively, by using the Schaffer test. The highest removal efficiency of 95% was obtained at least 91.56 and a maximum of 94.76% was obtained under optimal conditions of all factors.
Conclusion: The results show that by optimization of factors, this process can be effectively used to remove bromide from aquatic environments.
Zeynab Akbarlou, Vali Alipour, Mohsen Heidari, Kavoos Dindarloo, Volume 4, Issue 2 (Spring, 2017)
Abstract
Background: Considering the severe health and environmental hazards caused by the entry of diazinon toxin into water resources, its removal is very important. Given the high costs of imported adsorbents, this research attempted to evaluate, for the first time, the efficiency of Iranian activated carbon in removing diazinon from aqueous solutions.
Methods: In this batch experimental study, the effects of contact time (5-90 minutes), adsorbent concentration (0.5-30 g/L), initial concentration of diazinon (5-50 mg/L), and pH (3-10) on the adsorption of diazinon onto the activated carbon were evaluated. Concentrations of diazinon were measured using a high pressure liquid chromatography (HPLC) instrument. The specific surface area of the adsorbent was determined by BET and BJH methods. The experimental adsorption data was analyzed using Langmuir and Freundlich isotherm models. Pseudo first-order and pseudo second-order kinetics models were employed to determine kinetics. Moreover, data was analyzed using SPSS version 19, and Pearson correlation and analysis of variance (ANOVA) tests were performed at a significance level of 0.05.
Results: The optimum contact time, sorbent dose, and pH were 30 minutes, 10 g/L, and 5, respectively. The adsorbent could adsorb diazinon with a removal efficiency of 92.5% under optimum conditions (initial concentration: 20 mg/L). The experimental data was better described by the pseudo-second order kinetic and Langmuir isotherm. A maximum adsorption capacity of 71.4 mg/g was calculated by the Langmuir isotherm model.
Conclusion: With respect to the high adsorption capacity of Iranian activated carbon, this sorbent can be considered an efficient adsorbent for the removal of diazinon from aqueous solutions.
Zahra Heidari, Mohsen Motevasel, Nematollah Jaafarzadeh, Volume 4, Issue 4 (Autumn, 2017)
Abstract
Background: This research studied the effect of UV light on pentachlorophenol (PCP) removal in the electro-Fenton (EF) process.
Methods: PCP was used as the pollutant in this study. The effects of Fenton’s reagent, i.e. hydrogen peroxide concentration, solution pH, and treatment time by EF (EF) and photoelectro-Fenton (PEF) processes, were studied to determine rates of PCP removal. The results showed that a better performance and a high removal efficiency were achieved by coupling UV radiation and the EF process.
Results: EF processes required more time to remove PCP, while after a reaction time of 10 minutes, the PEF achieved a removal efficiency of 90.4%; this value is higher than the maximum efficiency of the EF process (83.44% after 40 minutes). The kinetic mechanisms of both processes were examined and
compared. The rate constants at optimum conditions were 0.0455 and 0.0579 min−1 for EF and PEF processes, respectively.
Conclusion: Removal efficiency was obtained in the order of PEF > EF.
Aida Tayebiyan, Thamer Ahmad Mohammad, Mohammad Malakootian, Alireza Nasiri, Mohammad Reza Heidari, Ghazal Yazdanpanah, Volume 6, Issue 2 (Spring 2019)
Abstract
Background: Changes in temperature and precipitation pattern seriously affect the amount of river runoff coming into Dam Lake. These changes could influence the operating conditions of reservoir systems such as Jor hydropower reservoir system (Malaysia) with the total capacity of 150 MW. So, it is necessary to analyze the effect of changes in weather parameters on the river runoff and consequently, the hydropower production.
Methods: In this research, LARS-WG was used to downscale the weather parameters such as daily minimum temperature, maximum temperature, and precipitation based on one of the general circulation sub-model (HADCM3) under three emission scenarios, namely, A1B, A2, and B1 for the next 50 years. Then, the artificial neural network (ANN) was constructed, while rainfall and evapotranspiration were used as input data and river runoff as output data to discover the relationship between climate parameters and runoff at the present and in the future time.
Results: It was revealed that the monthly mean temperature will increase approximately between 0.3-0.7°C, while the mean monthly precipitation will vary from -22% to +22% in the next 50 years. These changes could shift the dry and wet seasons and consequently, change the river runoff volume. In most months, the results of models integration showed reductions in river runoff.
Conclusion: It can be concluded that the output of hydropower reservoir system is highly dependent on the river runoff. So, the impacts of climate changes should be considered by the reservoir operators/managers to reduce these impacts and secure water supplies.
Mehdi Asghari, Gholamabbas Fallah Ghalhari, Hamidreza Heidari, Rahmatollah Moradzadeh, Sadegh Samadi, Reza Tajik, Mohammadjavad Ghanadzadeh, Volume 9, Issue 4 ( Autumn 2022)
Abstract
Background: Climate change is one of the most complex human challenges in the future. One of the consequences of climate change is the exposure of people to heat stress, especially in the outdoor environments. The aim of this study was to model the changes in the trend of exposure to heat stress in outdoor environments in the coming decades in the context of climate change and global warming.
Methods: The Wet Bulb Globe Temperature (WBGT) index, Canadian Earth System Model (CanESM2), and the Statistical Down Scaling Model (SDSM) were used in a semi-arid climate. In this study, Arak station was considered as a representative of Iran’s semi-arid climate. In this research, the daily data of the minimum and maximum temperatures, humidity, and WBGT index were used from 2011 to 2099.
Results: The minimum and maximum air temperatures in the study station show an increasing trend in three time periods. Also, based on the three studied scenarios, air temperature and WBGT index have an upward and positive trend and relative humidity has a downward and negative trend in the coming decades.
Conclusion: In general, increasing the exposure of people to heat stress at the study station in the coming decades and based on the simulations of atmospheric general circulation models (GCMs), will not be unexpected.
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