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Showing 6 results for Ashrafi
Introducing an Appropriate Model using Support Vector Machine for Predicting Carbon Monoxide Daily Concentration in Tehran Atmosphere
Roohollah Noori, Gholamali Hoshyaripour, Khosro Ashrafi, Omran Rasti,
Volume 6, Issue 1 (5-2013)
Abstract
Backgrounds and Objectives: Precise air pollutants prediction, as the first step in facing air pollution problem, could provide helpful information for authorities in order to have appropriate actions toward this challenge. Regarding the importance of carbon monoxide (CO) in Tehran atmosphere, this study aims to introduce a suitable model for predicting this pollutant.
Materials and Method: We used the air pollutants and meteorological data of Gholhak station located in the north of Tehran these data provided 12 variables as inputs for predicting the average CO concentration of the next day. First, support vector machine (SVM) model was used for forecasting CO daily average concentration. Then, we reduced the SVM inputs to seven variables using forward selection (FS) method. Finally, the hybrid model, FS-SVM, was developed for CO daily average concentration forecasting.
Result: In the research, we used correlation coefficient to evaluate the accuracy of both SVM and FS-SVM models. Findings indicated that correlation coefficient for both models in testing step was equal (R~0.88). It means that both models have proper accuracy for predicting CO concentration. However, it is noteworthy that FS-SVM model charged fewer amounts of computational and economical costs due to fewer inputs than SVM model.
Conclusion: Results showed that although both models have relatively equal accuracy in predicting CO concentration, FS-SVM model is the superior model due to its less number of inputs and therefore, less computational burden.
Determining the Contribution of Gas Emissions from Cars and Estimating the Distribution of CO Emissions in Enclosed Parking
Kh Ashrafi, M Shafie Pour Motlagh, M.s Mousavi, M.h Niksokhan, H.r Vosoughifar,
Volume 8, Issue 4 (3-2016)
Abstract

Background and Objectives: In this study, contribution of exhaust emission and CO distribution was estimated in enclosed residential complex parking.

Materials and Methods: This was a descriptive - analytical study consisted of two stages. In the first stage, the emission contribution of vehicles was determined. In order to determine the contribution of exhaust gas emissions, through gas species, only four species CO, O2, CO2, and N2 were measured. Concentration of CO, O2, and CO2 was estimated using data obtained from the vehicle emissions monitoring system. The amount of N2 was estimated from sum ratio of all species, which equals to 1. Then, using computational methods, the amount of the emission contribution from vehicles. In the second phase, to measure the distribution of CO pollutant, gas sampling and collecting was performed using sampling bags made of inert materials with a volume of 10 l at six points. Sampling was conducted in accordance with the requirements of OSHA ID 210. The Obtained data were analyzed using SPSS Ver.16 software and Pearson statistical test (P > 0.05 means there was no significant difference).

Results: Maximum contribution was estimated for Pride with amount of 44.4 g/s and minimum contribution was estimated for Tiba with amount of 0.3 g/s. The minimum and maximum distribution value of CO concentration was achieved 3.6 and 69.48 ppm respectively. It was found that no significant relationship was observed between the values of exhaust emissions and CO distribution. However, the distribution of concentration was associated with locations and the number of openings, the number and type of vehicle, time of operation of the vehicle, the vehicle performance, and environmental factors.

Conclusion: Measuring vehicles CO emission indicated  that the concentration was beyond the permissible level recommended by the World Health Organization at some. Moreover, it was indicated that natural air conditioning is an effective alternative for improving the air quality in built environments and suitable quality in built environments is achievable through reasonable architectural design, without need to spend too much expense.


Efficiency evaluation mesopore sillica nanoporous materials in removal of cephalexin from aqueous solution by response surface methodology
H Kamani, Ah Panahi, Sd Ashrafi, F Kord Mostafapour, Ns Omrani Gargari,
Volume 10, Issue 3 (12-2017)
Abstract
Background and Objective: Extreme use of antibiotics and discharging to the environment lead to serious consequences. Mesoporous silica such as MCM-41 material is widely used to absorb contaminants from the aqueous solution. The aim of this study was to evaluate mesoporous synthesis of MCM-41 and its efficacy for removal of the antibiotic cephalexin from aqueous solution.
Materials and Methods: Physical characteristics and absorbent structure synthesized by techniques BET, FTIR and XRD were analyzed. The effect of variables such as pH values (3, 7, 11), the dose of MCM-41 (200, 500, 800 mg/L), initial concentration of cephalexin (50, 75, 100 mg/L), contact time (30, 60, 90 min), and process temperature (20, 30, 40 0C) on absorption of cephalexin were studied. In order to achieve the optimal experimental conditions, response surface methodology (RSM) model was used.
Results: The results showed that pH (p=0.0001), adsorbent dose (p=0.0001), initial concentration of cephalexin (p=0.0001), contact time (p=0.01), pH2 (p=0.0002) and pH (p=0.04) and initial concentration had a significant impact on the response variable. The optimum removal condition based on analysis of variance and the model was at the reaction time 90 min, pH 3, initial concentration 50 mg/L and adsorption dose 600 mg/L. Under these conditions, the removal efficiency of 81.1% was achieved.
Conclusion: The results showed that adsorption process with the mesoporous MCM-41 had a high efficiency on the removal of cephalexin from the aqueous environments.
 

Non-carcinogenic risk assessment of Hg and Cu in streets dusts of Zahedan city
M Moradi Baseri, H Kamani, Sd Ashrafi, E Bazrafshan, F Kord Mostafapour,
Volume 11, Issue 3 (12-2018)
Abstract
Background and Objective: Street dust is an important factor in urban pollution which consists of soil, particulate matters and heavy metals. At present, over half of the world’s population lives in urban areas. Therefore, this study aimed to investigate health risks of heavy metals in street dusts in Zahedan.
Materials and Methods: The samples of street dust were collected in Zahedan. After preparation, the samples, were injected to ICP-MS for determination the amount of Hg and Cu. According to the measured concentrations, Hazard quotient (HQ) and hazard index (HI) were calculated to evaluate the health risk assessment.
Results: Results showed that Hazard quotient for both Hg and Cu was less than 1 for children and adult. HQ for Hg and Cu was in order of HQingestion >HQdermal >HQinhalation> HQvapour for adults and HQvapour > HQingestion > HQdermal > HQinhalation  for children. HI was also less than 1.
Conclusion: The value of HQ showed that inhalation of mercury vapor and ingestion were the main routes of exposure to Hg for children and adults. The non-carcinogenic risk was within the safe value (HI <1) in this study.
 

Ranking of hazardous organic pollutants using emission, reactivity and health criteria in the South Pars Zone
M Moradzadeh, Kh Ashrafi, M Shafiepourmotlagh,
Volume 11, Issue 4 (3-2019)
Abstract
Background and Objective: Hydrocarbon processing industries are considered as potential sources of volatile organic compounds (VOCs) due to their specific nature. These compounds can directly or indirectly through producing secondary pollutants have adverse effects on the health of individuals. Therefore, identification of them is an important step in the formulation of control programs. This study aimed to identify the type and amount of the most important volatile organic compounds in the South Pars region.
Materials and Methods: In this study, industrial processes located in the region were investigated and information was gathered for estimation of VOCs emissions. The emission was estimated over a one-year period and was ranked according to three criteria including emission, health hazards and ozone production potential.
Results: The results showed that the greatest emission was due to equipment leakage and storage tanks (64%), cooling towers (21%) and flaring (11%). The 171 VOCs were determined in Plum of these processes and propylene had the greatest contribution (21%). The alkenes had the highest share in total mass (41%) and ozone production (78%). By weighting the list based on the three criteria mentioned above, formaldehyde is the most important emitted VOC and the main sources of it were olefins and aromatic units.
Conclusion: This method can be a useful tool for identifying effective organic compounds in such areas. Here, the optimum control strategy is mitigating of emission of formaldehyde from the aromatic and olefins processes. The next priority is to control propylene, ethylene and butylene emission sources.
 

Estimation of Tehran's particulate matter 2.5 micrometers or less in diameter (PM2.5) health effects, using BenMAP-CE
R Bayat, Kh Ashrafi, M Shafiepour Motlagh, Ms Hassanvand, R Daroudi,
Volume 12, Issue 3 (12-2019)
Abstract
Background and Objective: Despite the significant improve in air quality in Tehran in 2018 and reducing the average concentration of most pollutants, compared to previous years, air quality is still far from the WHO air quality guideline level and national air quality standards. The purpose of this study was to estimate the effects of air pollution on health in Tehran by considering the spatial distribution of particulate matter 2.5 micrometers or less in diameter (PM2.5) and population in determining exposure levels.
Materials and Methods: In this study, while introducing the GEMM concentration–response function and BenMAP-CE software, the mortality attributed to PM2.5 in Tehran and its distribution for 2017 and 2018 was calculated. Hourly PM2.5 from monitoring stations used to estimate the mean PM2.5 for 349 Tehran neighborhoods.
Results: The results showed that the average population weighted PM2.5 concentrations in Tehran in 2017 and 2018 was estimated to be 31.8 and 26.2 µg/m3 respectively. Using the GEMM function, about 7,377 (95% CI: 6,126-8,581) total mortality attributed to PM2.5 was estimated in adults in 2017 (> 25 years) and the figure for 2018 was estimated as 6,418 (95% CI: 5,918-6,753).
Conclusion: The spatial distribution of deaths attributable to PM2.5 showed that the total mortality rate per 100000 in the districts 16 and 18 of the Tehran municipality were higher than other districts and the lowest rate observed in the district 1.

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