Question analysis, is a set of methods through which the effectiveness and efficiency of each que... more Question analysis, is a set of methods through which the effectiveness and efficiency of each question and the entire exam questions can be measured. By recognizing the affecting factors, we will be able to design more appropriate and standard exams to increase the efficiency and effectiveness of every single question. Analyzing the questions makes it possible to evaluate the characteristics of each question as well as providing assurance on standard format of questions to be further assessed for expected ability or attributes. The present research was a descriptive study carried out at the School of Public Health (Qazvin University of Medical Sciences) in 2009-2010. A total of 592 questions designed for the final exams of different fields of study including the public health, environmental health, and occupational health were evaluated. Each question was evaluated for its difficulty ratio and distinction ratio to determine the strength and weak points of every single question and t...
The integrated hospital solid waste management emphasizes the need to conduct a survey based on a... more The integrated hospital solid waste management emphasizes the need to conduct a survey based on a standardized method that equally be analyzed at national level. This study aimed to test the usability of a national tool to do integration data analysis of hospital waste management status. Then, a typical study was conducted in Karaj hospitals. Also, critical analysis of hospital's solid waste management aspects was done, and shortcomings in the aspects were identified. The pilot study results showed that the daily per capita waste generations were reported to be 4.2±0.49 kg/available bed, 5.8±0.63 kg/occupied bed, and 10.3±0.9 kg/inpatient. The names of the hospitals were omitted when they were named from H1 to H8. So the highest and lowest daily waste generation rate were 5.5±0.35 and 2.6±0.78 kg/available bed in H7 and H3 hospitals, respectively. In this study, total infectious wastes per capita were reported to be 2.3±0.39 kg/available bed/day, 3±0.5 kg/occupied bed/day and 5....
We propose a new approach for solving nonlinear Klein–Gordon and sine-Gordon equations based on r... more We propose a new approach for solving nonlinear Klein–Gordon and sine-Gordon equations based on radial basis function-pseudospectralmethod (RBF-PS). The proposed numerical method is based on quasiinterpolation of radial basis function differentiation matrices for thediscretization of spatial derivatives combined with Runge–Kutta time stepping method in order to deal with the temporal part of the problem.The method does not require any linearization technique; in addition, a new technique is introduced to force approximations to satisfy exactlythe boundary conditions. The introduced scheme is tested for a number of one- and two-dimensional nonlinear problems. Numerical results andcomparisons with reported results in the literature are given to validate the presented method, and the reported results show the applicabilityand versatility of the proposed method.
AbstractThe response surface method (RSM) was used to find out the best conditions for the nitrat... more AbstractThe response surface method (RSM) was used to find out the best conditions for the nitrate removal by electrocoagulation (EC) process with aluminum electrodes. The independent variables wer...
Abstract: Background and Objectives: leachate from municipal solid waste landfill is a strong sew... more Abstract: Background and Objectives: leachate from municipal solid waste landfill is a strong sewage having hazardous toxic substances. It should be treated by choosing a simple, economical, and eco-friendly method. The aim of this study is reduction of COD from the Qom City landfill leachate using electrocoagulation process. Materials and Methods: The experimental study was carried out at bench scale using a batch reactor during 2010. We used a Plexiglas reactor having 0.7 liter capacity, containing nine plate aluminum ...
Background: An excessive level of heavy metals is one of the most common environmental pollutants... more Background: An excessive level of heavy metals is one of the most common environmental pollutants that damage human health. Electrocoagulation (EC) is an electrochemical technique with different applications that has been used for lead removal from wastewater. Objective: The aim of this study was to determine efficiency of electrocoagulation process for lead removal from wastewater. Methods: This laboratory study was performed in School of Public Health affiliated to Qazvin University of Medical Sciences during 2013. A laboratory batch electrocoagulation reactor was designed and constructed from Perspex with dimensions of 17 cm* 12 cm* 40 cm and was applied for coagulation and flotation. The aluminium electrodes were connected in a bipolar configuration. Electrolysis was performed for 30 min in each run. Samples were taken every 5 minutes and parameters such as current density, electrolysis time, pH and different concentrations of lead were measured. The lead concentration was 5, 10...
Background: Noise pollution in cities is one of the most important health problems which is growi... more Background: Noise pollution in cities is one of the most important health problems which is growing in severity. Objective: To determine the level of equivalent noise and traffic sound in various cities of Qazvin province. Methods: This cross-sectional study was conducted in the winter of 2010 in Qazvin. Measurements were performed by the sound level meter 1353H (TES, Taiwan). The main streets and intersections on the city maps were considered as measuring stations. The levels of equivalent noise, statistical noise, and traffic noise were measured based on the ISO 1999 method approved by the Environmental Protection Organization. Data were analyzed by one sided, two sided, paired t-test. Findings: Of total measuring stations, 63% were found to have equivalent noise level higher than the standard recommended for residential-commercial areas and 24% within the standard levels. Conclusion: In all cities under study, the equivalent noise level was higher than that recommended for reside...
The Journal of Qazvin University of Medical Sciences, 2014
determination. Findings: The maximum dye adsorption occurred during the first 30 minutes. The sor... more determination. Findings: The maximum dye adsorption occurred during the first 30 minutes. The sorption capacity for adsorption of the dye was found to be 2.76 mg/gr. The dye removal efficiency was increased from 87% to 97.2% by decreasing the initial concentration of dye from 100 to 25 mg/l. By increasing the adsorbent dose from 0.05 to 0.4 g/l, the dye removal efficiency was increased from 70.7% to 94.8%. The general order kinetic model provided the best fit to the pseudo-second order kinetic adsorption model and the equilibrium data were best fitted to the Freundlich isotherm model. The maximum efficiency was found to be 97.2%. Conclusion: Multi-walled carbon nanotubes can be effective for removal of 2-naphthol orange dye.
The current study presents an investigation on the waste management in the cattle slaughterhouse ... more The current study presents an investigation on the waste management in the cattle slaughterhouse by the following objectives: a) to identify the existing waste management practices in relation to sources, quantity and characteristic of wastes; b) to identify the situation of production, collection, storage, transportation, processing and recycling, and final disposal of wastes and the problems of existing waste management practices. In order to obtain reliable information and filling the check list, site surveys were conducted when the management of the slaughter-house was interviewed in waste management practices. The total produced industrial waste in studying units' was found to be 10252 tons/year. The per capita waste generations were reported to be 54.6 kg/cattle/day and 11.1 kg/sheep/day. Also, more than 98% of the hazardous waste produced can be infectious. However, it is important to keep in mind that setting an operational program and careful monitoring of its optimal e...
Ferdowsi University of Mashhad, Mashhad, Iran., 2020
We propose a new approach for solving nonlinear Klein–Gordon and sine-Gordon equations based on r... more We propose a new approach for solving nonlinear Klein–Gordon and sine-Gordon equations based on radial basis function-pseudospectral method (RBF-PS). The proposed numerical method is based on quasiinterpolation of radial basis function differentiation matrices for the discretization of spatial derivatives combined with Runge–Kutta time stepping method in order to deal with the temporal part of the problem. The method does not require any linearization technique; in addition, a new technique is introduced to force approximations to satisfy exactly the boundary conditions. The introduced scheme is tested for a number of one- and two-dimensional nonlinear problems. Numerical results and comparisons with reported results in the literature are given to validate the presented method, and the reported results show the applicability and versatility of the proposed method.
This study aims to investigate the effect of the main parameters on the performance of a continuo... more This study aims to investigate the effect of the main parameters on the performance of a continuous flow electro-coagulation (EC) process for nitrate removal efficiency and its operating costs. For this purpose, the Taguchi experimental design with orthogonal array L27 (313) was applied to analyze the effects of selected parameters, namely initial nitrate concentration, inlet flow rate, current density and initial pH. According to the analysis of variance results, the inlet flow rate and the current density were recognized to be the most effective factors playing a pivotal role in nitrate removal efficiency by using an EC process. The optimum conditions of initial nitrate concentration, inlet flow rate, current density and initial pH were found to be 100 mg/L, 50 mL/min, 80 A/m2 and 8, respectively. As a result, the observed nitrate removal efficiency under these conditions was 61.70%. In addition, operating costs were evaluated as 1.278 US$/g NO3-removed. Finally, a high correlatio...
Question analysis, is a set of methods through which the effectiveness and efficiency of each que... more Question analysis, is a set of methods through which the effectiveness and efficiency of each question and the entire exam questions can be measured. By recognizing the affecting factors, we will be able to design more appropriate and standard exams to increase the efficiency and effectiveness of every single question. Analyzing the questions makes it possible to evaluate the characteristics of each question as well as providing assurance on standard format of questions to be further assessed for expected ability or attributes. The present research was a descriptive study carried out at the School of Public Health (Qazvin University of Medical Sciences) in 2009-2010. A total of 592 questions designed for the final exams of different fields of study including the public health, environmental health, and occupational health were evaluated. Each question was evaluated for its difficulty ratio and distinction ratio to determine the strength and weak points of every single question and t...
The integrated hospital solid waste management emphasizes the need to conduct a survey based on a... more The integrated hospital solid waste management emphasizes the need to conduct a survey based on a standardized method that equally be analyzed at national level. This study aimed to test the usability of a national tool to do integration data analysis of hospital waste management status. Then, a typical study was conducted in Karaj hospitals. Also, critical analysis of hospital's solid waste management aspects was done, and shortcomings in the aspects were identified. The pilot study results showed that the daily per capita waste generations were reported to be 4.2±0.49 kg/available bed, 5.8±0.63 kg/occupied bed, and 10.3±0.9 kg/inpatient. The names of the hospitals were omitted when they were named from H1 to H8. So the highest and lowest daily waste generation rate were 5.5±0.35 and 2.6±0.78 kg/available bed in H7 and H3 hospitals, respectively. In this study, total infectious wastes per capita were reported to be 2.3±0.39 kg/available bed/day, 3±0.5 kg/occupied bed/day and 5....
We propose a new approach for solving nonlinear Klein–Gordon and sine-Gordon equations based on r... more We propose a new approach for solving nonlinear Klein–Gordon and sine-Gordon equations based on radial basis function-pseudospectralmethod (RBF-PS). The proposed numerical method is based on quasiinterpolation of radial basis function differentiation matrices for thediscretization of spatial derivatives combined with Runge–Kutta time stepping method in order to deal with the temporal part of the problem.The method does not require any linearization technique; in addition, a new technique is introduced to force approximations to satisfy exactlythe boundary conditions. The introduced scheme is tested for a number of one- and two-dimensional nonlinear problems. Numerical results andcomparisons with reported results in the literature are given to validate the presented method, and the reported results show the applicabilityand versatility of the proposed method.
AbstractThe response surface method (RSM) was used to find out the best conditions for the nitrat... more AbstractThe response surface method (RSM) was used to find out the best conditions for the nitrate removal by electrocoagulation (EC) process with aluminum electrodes. The independent variables wer...
Abstract: Background and Objectives: leachate from municipal solid waste landfill is a strong sew... more Abstract: Background and Objectives: leachate from municipal solid waste landfill is a strong sewage having hazardous toxic substances. It should be treated by choosing a simple, economical, and eco-friendly method. The aim of this study is reduction of COD from the Qom City landfill leachate using electrocoagulation process. Materials and Methods: The experimental study was carried out at bench scale using a batch reactor during 2010. We used a Plexiglas reactor having 0.7 liter capacity, containing nine plate aluminum ...
Background: An excessive level of heavy metals is one of the most common environmental pollutants... more Background: An excessive level of heavy metals is one of the most common environmental pollutants that damage human health. Electrocoagulation (EC) is an electrochemical technique with different applications that has been used for lead removal from wastewater. Objective: The aim of this study was to determine efficiency of electrocoagulation process for lead removal from wastewater. Methods: This laboratory study was performed in School of Public Health affiliated to Qazvin University of Medical Sciences during 2013. A laboratory batch electrocoagulation reactor was designed and constructed from Perspex with dimensions of 17 cm* 12 cm* 40 cm and was applied for coagulation and flotation. The aluminium electrodes were connected in a bipolar configuration. Electrolysis was performed for 30 min in each run. Samples were taken every 5 minutes and parameters such as current density, electrolysis time, pH and different concentrations of lead were measured. The lead concentration was 5, 10...
Background: Noise pollution in cities is one of the most important health problems which is growi... more Background: Noise pollution in cities is one of the most important health problems which is growing in severity. Objective: To determine the level of equivalent noise and traffic sound in various cities of Qazvin province. Methods: This cross-sectional study was conducted in the winter of 2010 in Qazvin. Measurements were performed by the sound level meter 1353H (TES, Taiwan). The main streets and intersections on the city maps were considered as measuring stations. The levels of equivalent noise, statistical noise, and traffic noise were measured based on the ISO 1999 method approved by the Environmental Protection Organization. Data were analyzed by one sided, two sided, paired t-test. Findings: Of total measuring stations, 63% were found to have equivalent noise level higher than the standard recommended for residential-commercial areas and 24% within the standard levels. Conclusion: In all cities under study, the equivalent noise level was higher than that recommended for reside...
The Journal of Qazvin University of Medical Sciences, 2014
determination. Findings: The maximum dye adsorption occurred during the first 30 minutes. The sor... more determination. Findings: The maximum dye adsorption occurred during the first 30 minutes. The sorption capacity for adsorption of the dye was found to be 2.76 mg/gr. The dye removal efficiency was increased from 87% to 97.2% by decreasing the initial concentration of dye from 100 to 25 mg/l. By increasing the adsorbent dose from 0.05 to 0.4 g/l, the dye removal efficiency was increased from 70.7% to 94.8%. The general order kinetic model provided the best fit to the pseudo-second order kinetic adsorption model and the equilibrium data were best fitted to the Freundlich isotherm model. The maximum efficiency was found to be 97.2%. Conclusion: Multi-walled carbon nanotubes can be effective for removal of 2-naphthol orange dye.
The current study presents an investigation on the waste management in the cattle slaughterhouse ... more The current study presents an investigation on the waste management in the cattle slaughterhouse by the following objectives: a) to identify the existing waste management practices in relation to sources, quantity and characteristic of wastes; b) to identify the situation of production, collection, storage, transportation, processing and recycling, and final disposal of wastes and the problems of existing waste management practices. In order to obtain reliable information and filling the check list, site surveys were conducted when the management of the slaughter-house was interviewed in waste management practices. The total produced industrial waste in studying units' was found to be 10252 tons/year. The per capita waste generations were reported to be 54.6 kg/cattle/day and 11.1 kg/sheep/day. Also, more than 98% of the hazardous waste produced can be infectious. However, it is important to keep in mind that setting an operational program and careful monitoring of its optimal e...
Ferdowsi University of Mashhad, Mashhad, Iran., 2020
We propose a new approach for solving nonlinear Klein–Gordon and sine-Gordon equations based on r... more We propose a new approach for solving nonlinear Klein–Gordon and sine-Gordon equations based on radial basis function-pseudospectral method (RBF-PS). The proposed numerical method is based on quasiinterpolation of radial basis function differentiation matrices for the discretization of spatial derivatives combined with Runge–Kutta time stepping method in order to deal with the temporal part of the problem. The method does not require any linearization technique; in addition, a new technique is introduced to force approximations to satisfy exactly the boundary conditions. The introduced scheme is tested for a number of one- and two-dimensional nonlinear problems. Numerical results and comparisons with reported results in the literature are given to validate the presented method, and the reported results show the applicability and versatility of the proposed method.
This study aims to investigate the effect of the main parameters on the performance of a continuo... more This study aims to investigate the effect of the main parameters on the performance of a continuous flow electro-coagulation (EC) process for nitrate removal efficiency and its operating costs. For this purpose, the Taguchi experimental design with orthogonal array L27 (313) was applied to analyze the effects of selected parameters, namely initial nitrate concentration, inlet flow rate, current density and initial pH. According to the analysis of variance results, the inlet flow rate and the current density were recognized to be the most effective factors playing a pivotal role in nitrate removal efficiency by using an EC process. The optimum conditions of initial nitrate concentration, inlet flow rate, current density and initial pH were found to be 100 mg/L, 50 mL/min, 80 A/m2 and 8, respectively. As a result, the observed nitrate removal efficiency under these conditions was 61.70%. In addition, operating costs were evaluated as 1.278 US$/g NO3-removed. Finally, a high correlatio...
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