Nasser Talebbeydokhti | Shiraz University (original) (raw)
Papers by Nasser Talebbeydokhti
Although Darcy-Weisbach (D-W) equation has been accepted as a standard resistance equation in pre... more Although Darcy-Weisbach (D-W) equation has been accepted as a standard resistance equation in pressurized flow, some researchers and engineers still prefer to utilize Hazen-Williams (H-W) equation for analyzing water distribution networks (WDNs) in practice. The main difference between roughness coefficients of these two resistance equations is that D-W friction factor varies with Reynolds number of flow field while H-W coefficient is usually considered as a fixed value for a specific material. In this paper, discrepancies between solving three pipe networks using these two resistance equations are investigated. These networks were solved using two hydraulic solver named gradient algorithm and finite element method assuming different values for roughness values. In order to compare the results, equivalent friction factors based on these two resistance equations were required to be used. In this regard, several methods for computing equivalent roughness values were selected from the ...
Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2020
Although many explicit correlations have already been presented as alternatives to implicit Coleb... more Although many explicit correlations have already been presented as alternatives to implicit Colebrook-White (C-W) formula, performances of C-W-based relations in pipe network analysis have not been investigated. In this study, 56 explicit relations available in the literature were implemented in the analysis of four water distribution networks while the benchmark solution is computed considering the implicit C-W formula. In the numerical experiment, these pipe networks were solved using three different h-based methods including h-based Newton-Raphson method, finite element method, and the gradient algorithm. In each scenario, one of these explicit relations was considered in the process of analyzing water networks. According to the obtained results, 15 explicit relations face the convergence problems which were identified as unreliable equations. Moreover, 15 explicit equations, which were successfully performed in analyzing all sample networks with the closest results to that of the benchmark solution, were introduced as the most accurate ones. Moreover, as many scenarios outperform those of the outdated explicit equation used for the same purpose in professional hydraulic solvers such as EPANET and WaterGEMS, it was recommended they be replaced with one of the explicit equations with higher accuracy. Finally, the achieved results demonstrate that the equation selected for computing Darcy-Weisbach friction factor has an inevitable impact not only on the accuracy but also on the convergence of pipe network analysis.
Journal of Applied Remote Sensing, 2019
Abstract. The potential of synthetic aperture radar (SAR) interferometry was shown to study the c... more Abstract. The potential of synthetic aperture radar (SAR) interferometry was shown to study the compaction of the aquifer system in Darab plain, Iran. In so doing, two different datasets, including Envisat advanced SAR (ASAR) spanning 2010 and Sentinel-1A spanning 2016 to 2017, were applied in small baseline subset time series analysis. To estimate the subsidence in the time period for which there is no SAR data available, i.e., 2010 to 2016, the time series analysis results separately obtained from the two datasets were to be integrated using an appropriate model, which should have been fitted to both sets of results. However, as both deformation time series results were calculated taking into account a distinct temporal reference, fitting the model was not a straightforward task. Accordingly, the main attempt was to find the subsidence value corresponding to the temporal reference of Sentinel-1A time series with respect to that of Envisat ASAR. This shift value was optimally determined using a genetic algorithm so as to minimize the misfit between the model and the deformation time series corresponding to the entire period. The average value of the root mean square error estimated as the misfit between the model and the calculated time series at all pixels is 0.011 m, which is an indication of the high performance of the proposed method for modeling the deformation time series. The integration results were further used to derive the stress–strain relationships to study the storage properties of the aquifer system. The fact that the strain linearly increases along with the decrease in water level in most piezometric wells indicates that the subsidence is highly correlated with groundwater exploitation.
Water Resources Management, 2018
Determination of flow resistance in open channel flows is not only important for practical engine... more Determination of flow resistance in open channel flows is not only important for practical engineering applications but also challenging because of multiple factors involved. The literature review reveals that despite of various data-driven formulas and schemes, only classic Manning's resistance equation and Keulegan's formula have been utilized in practice. It also indicates that sole application of Artificial Intelligence (AI) models facilitates roughness estimation while they have not been used within a systematic roughness estimator scheme. In this study, a new eight-step scheme is developed to predict grain and total Manning's coefficients when grain and form roughness are the major sources of friction, respectively. The new scheme not only uses a new explicit equation for computing hydraulic radius related to bed for estimating grain roughness coefficient but also utilizes AI models named artificial neural network and genetic programming in the seventh step for estimating form roughness coefficient. It improves R 2 for estimating Manning's grain coefficient and RMSE for estimating discharge by 21% and 64% comparing with that of one of common formulas available in the literature, respectively. Moreover, the new scheme incorporating AI models significantly enhances the accuracy of estimation results for predicting roughness coefficient and discharge comparing with the new scheme using new developed empirical formula based on RMSE, MARE and R 2 criteria. The obtained improvement demonstrates that application of AI models as a part of a data-based roughness estimator scheme, like the one suggested, may considerably improve the precision of prediction results of flow resistance and discharge.
Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2016
In the present research, external validation criteria and uncertainty analysis are conducted to p... more In the present research, external validation criteria and uncertainty analysis are conducted to predict maximum scour depth at downstream of the stilling basins using evolutionary polynomial regression (EPR) and model tree (MT) and nonlinear regression (NLR). Data sets used to develop models were collected from experimental models of stilling basins. Effective parameters on the scour depth were included those of discharge, approaching flow depth, mean flow velocity, geometric characteristics of stilling basins and physical properties of bed sediments at downstream of stilling basins. At first, MT and EPR models are implemented based on input-output data sets and result of performances for training and testing stages are evaluated. In addition, external validations and uncertainty analyses on the formulations given by EPR and MT are carried out using statistical errors functions and have absolute mean prediction errors less than that NLR technique. Finally, results of uncertainty and the prediction errors are compared with the GEP, MT, EPR and NLR models to select GEP model as a reliable model with the highest accuracy and smaller errors than other models.
Earth Surface Processes and Landforms, 2003
The objective of this experimental study was to account for the role of sediment availability and... more The objective of this experimental study was to account for the role of sediment availability and specific gravity on cluster formation and cluster geometric characteristics (spacing and size). To isolate the effects of sediment availability and specific gravity on cluster evolution, mono-sized spheres were used to simulate the cluster evolutionary cycle. Overall, twelve experimental runs were carried out in the laboratory flume. Six of these tests were performed by using glass spheres (specific gravity, SG D 2Ð58) and the other six by employing an equal combination of glass and Teflon spheres (SG D 2Ð12) of the same diameter to evaluate the role of specific gravity on cluster evolution. The three sediment availability conditions that were investigated here simulated isolated gravel elements, pool-riffle sequences and densely packed gravel-bed. An advanced image analysis technique was employed to track the evolution of cluster microforms and provide quantitative information about the size and shape of clusters and the number of clusters per unit area. The results of this study showed that: (1) sediment availability affects the architecture and size of cluster microforms; and (2) clusters consisting of mono-sized sediments start disintegrating at twice the incipient conditions. By performing complementary tests for the isolated gravel elements case, it was found that the evolutionary cycle of individual clusters could be described as follows, in order of increasing stress: no cluster ! two particle cluster ! comet ! triangle ! rhomboid ! break up.
Iranian Journal of Science and Technology, Transactions of Civil Engineering
Coastal Engineering Journal
The rate of nitrate adsorption by a nitrate selective ion exchange resin was investigated in a we... more The rate of nitrate adsorption by a nitrate selective ion exchange resin was investigated in a well-stirred batch experiments. The kinetic experimental data were simulated with diffusion models including external mass transfer, particle diffusion and chemical adsorption. Particle pore volume diffusion and particle surface diffusion were taken into consideration separately and simultaneously in the modeling. The model equations were solved numerically using the Crank-Nicholson scheme. An optimization technique was employed to optimize the model parameters. All nitrate concentration decay data were well described with the all diffusion models. The results indicated that the kinetic process is initially controlled by external mass transfer and then by particle diffusion. The external mass transfer coefficient and the coefficients of pore volume diffusion and surface diffusion in all experiments were close to each other with the average value of 8.3×10-3 cm/S for external mass transfer ...
In recent years, new techniques for solving complex problems in engineering are proposed. One of ... more In recent years, new techniques for solving complex problems in engineering are proposed. One of these techniques is JPSO algorithm. With innovative changes in the nature of the jump algorithm JPSO, it is possible to construct a graph-based solution with a new algorithm called G-JPSO. In this paper, a new algorithm to solve the optimal control problem Fletcher-Powell and optimal control of pumps in water distribution network was evaluated. Optimal control of pumps comprise of optimum timetable operation (status on and off) for each of the pumps at the desired time interval. Maximum number of status on and off for each pumps imposed to the objective function as another constraint. To determine the optimal operation of pumps, a model-based optimization-simulation algorithm was developed based on G-JPSO and JPSO algorithms. The proposed algorithm results were compared well with the ant colony algorithm, genetic and JPSO results. This shows the robustness of proposed algorithm in findin...
Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2021
Mixture of industrial and municipal wastewater causes an increase in concentration of heavy metal... more Mixture of industrial and municipal wastewater causes an increase in concentration of heavy metals in wastewater and sludge. Sludge can be recycled to vermicompost. Heavy metal concentration of resulting vermicompost is important, as they are being used in green spaces, where irrigation disperses heavy metals into the underground water resources and affect the quality of underground water. We study concentration of iron and lead in substrate and worm tissues over time and depth in batch reactors. Two bins of 40 × 40 × 120 cm 3 (length × width × depth) are built and filled with sludge (T1) and sludge + soil (T2). We put perforated tubes in four sides of bins and a faucet with constant flow of distilled water above each pilot to produce water flow from top to the bottom of reactors. Pilots run in two stages; with and without the presence of earthworms. To study changes in worm tissues, two bins of 30 × 30 × 30 cm 3 (length × width × depth) are built, and earthworm is then added. These bins are filled with sludge (T3) and sludge + soil (T4). Obtained results from (T1) and (T2) confirm heavy metal concentration decrease over time, but increase through depth of reactors. Presence of worms in both reactors shows decrease in concentration of heavy metals. Results obtained from (T3) and (T4) indicate reduction in concentration of lead and iron in substrate and bioaccumulation in worm body mass. TOC of substrate was decreased but TKN increased during time. Initial C/N ratio is 22.2 in pilot T3, and it is decreased to 7.4 and final pH is near 7.
Labyrinth spillway has become an appropriate choice to increase an existing spillway's capacity. ... more Labyrinth spillway has become an appropriate choice to increase an existing spillway's capacity. Thus, it is necessary to understand the hydraulic performance of labyrinth spillways/weirs. This paper numerically solves turbulent ow over labyrinth spillways/weirs and determines the discharge coe cients. Reynolds governing equations, turbulence k " model, and the Volume Of Fluid (VOF) model are numerically solved to de ne pressure, velocity, and the free surface ow pro les. The numerical results are comparable to those obtained from physical modeling with maximum 6.43% error relative to results of physical modeling. Present study indicates that numerical simulation can be used to supplement physical modeling. Thus, by using numerical solutions, the site speci cs of the spillway which are often di erent from the conditions of design curves can be investigated. Also, the e ect of di erent shapes of apex on discharge capacity of the labyrinth spillway is investigated in this study. The analyses show that labyrinth spillways with round apex shape are the most e cient spillways. Numerical determination of free water surface is presented and discussed, which is helpful for optimum design of stilling basin and leading walls.
Scientia Iranica, 2013
A hybrid numerical model is introduced for simulation of cohesive sediments concentration profile... more A hybrid numerical model is introduced for simulation of cohesive sediments concentration profiles in a surf zone. For this purpose, wave height reduction must be considered, due to muddy beds and wave breaking. Models, such as Sanford and Maa’s erosion model, Krone’s sedimentation model, Tajima’s wave breaking model and the visco-elastic–plastic rheological model, are used to investigate the interaction of wave and bed and to predict the concentration profile. A splitting algorithm has been used to split the three-dimensional advection–diffusion equation into a horizontal, two-dimensional equation, and a vertical, one-dimensional equation, due to different length scales. The one-dimensional equation is discretized over a non uniform grid, and, then solved implicitly using the QUICKEST scheme (third order in time and space). The two-dimensional equation is divided into two parts (advection and diffusion) and each part is separately solved at different time steps. A suitable mesh, re...
Journal of Environmental Protection, 2021
The Severe Acute Respiratory Syndrome-Coronavirus Outbreak 2019 (CO-VID-19) has caused worldwide ... more The Severe Acute Respiratory Syndrome-Coronavirus Outbreak 2019 (CO-VID-19) has caused worldwide concern and has affected all aspects of human life. The study objective is to assess and evaluate the direct and indirect positive and negative environmental effects of COVID-19 in urban areas. Collected data for Iran as a case study is presented, comprehensively completing the dynamic effect of COVID-19 on the environment. The analysis results indicate that despite the temporarily positive effects of coronavirus on the environment, such as improvement in air quality (15%-20% reduction of NO2 in Tehran), environmental noise reduction, cleaner beach and coastal areas due to implementing lockdowns, there are negative short-and long-term effects such as excessive water consumption (10%-40% increase in Iranian cities), reduce in waste recycling and significant increase in both residential and medical solid waste generation (10%-77% increase in medical waste generation and 10%-50% increase residential waste generation in Iranian cities), which leads to pollution or/and degradation of the environment (air, water and land). Moreover, with the global economic relaunching relaunch in most countries in the coming months, it could result in adverse effects such as increase in the greenhouse gas emissions. Assessment of environmental impacts, type and scale, could help for better planning and mitigation of the future pandemics.
Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2021
Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2021
Journal of Hazardous Materials, 2022
The present study employed an anoxic packed bed biofilm reactor (AnPBR) inoculated with in-situ b... more The present study employed an anoxic packed bed biofilm reactor (AnPBR) inoculated with in-situ biosurfactant-producing bacteria for the biodegradation of petroleum wastewater. Highly acclimated biomass decreased the start-up phase period and with increasing the initial total petroleum hydrocarbon (TPH) concentration from 1.5 to 4 g/L was accompanied by TPH and chemical oxygen demand (COD) removal efficiencies of above 99% and 96%, respectively. Decreasing hydraulic retention time (HRT) from 24 to 6 h caused an increase in the specific hydrocarbon utilization rate value from 0.45 to 1.66 gTPH/gbiomass.d. Moreover, dehydrogenase activity, surfactin, and rhamnolipid reached 31.8 μgTF/gbiomass.d, 95.1, and 27.1 mg/L, respectively. The biodegradation kinetic coefficients such as K, Ks, Kd, Y and µmax were 0.784 (d-1), 0.005 (g/L), 0.138 (d-1), 0.569 (gVSS/gCOD), and 0.446 (d-1), respectively. Dropping of bioreactor performance, especially TPH removal efficiency from 99% to 37.6% in the absence of nitrate after 10 days, indicates anoxic metabolism has been the dominant biodegradation pathway. The effluent chromatogram of gas chromatography/flame ionization detector (GC/FID) showed aliphatic, cyclic aliphatic, and aromatic hydrocarbons efficiently degraded. According to the high degradation rate of AnPBR in different operational parameters, it can be recommended for the treatment of oil-contaminated wastewater.
Scientia Iranica, 2021
Lattice Boltzmann method (LBM) has emerged as a fast, precise, and efficient numerical solution t... more Lattice Boltzmann method (LBM) has emerged as a fast, precise, and efficient numerical solution to solve differential equations. There seems to be a dearth of research regarding the solution for groundwater flow in unconfined aquifer using LBM. Accordingly, in this study, an innovative numerical solution based on LBM was introduced to solve groundwater flow in unconfined aquifers, taking into account D2Q9 scheme. The solutions obtained from the proposed LBM were compared to results stemmed from three different unconfined groundwater problems with known solutions. Both steady and transient conditions for groundwater flow were considered in simulations. It was deduced that the proposed LBM could simulate the unconfined groundwater flow satisfactorily.
Applied Ocean Research, 2021
Abstract Shorelines around the world are of great importance because of their role in people'... more Abstract Shorelines around the world are of great importance because of their role in people's lives. Therefore, understanding its behavior seems to be vital. Shoreline changes and its realignments are highly nonlinear and finding a method in such a way that it could model its patterns would be very useful. ANN's are popular methods, as they have been applied to numerous problems. In this study, recurrent ANNs such as NARNET and NARXNET are used to model the shoreline changes in Narrabeen Coast, Australia, between 1980 and 2014. Their outputs represent a reliable performance for predicting shoreline changes based on historical data. These results also are compared with other methods, including RBF, GRNN, and TDNN. The NARNET showed most accurate results with MAPE= 17.18%, and the NARXNET had the best correlation with CC=0.26. It has been indicated that the NARNET and NARXNET are better methods since they need less extra data, besides the shoreline position itself.
Although Darcy-Weisbach (D-W) equation has been accepted as a standard resistance equation in pre... more Although Darcy-Weisbach (D-W) equation has been accepted as a standard resistance equation in pressurized flow, some researchers and engineers still prefer to utilize Hazen-Williams (H-W) equation for analyzing water distribution networks (WDNs) in practice. The main difference between roughness coefficients of these two resistance equations is that D-W friction factor varies with Reynolds number of flow field while H-W coefficient is usually considered as a fixed value for a specific material. In this paper, discrepancies between solving three pipe networks using these two resistance equations are investigated. These networks were solved using two hydraulic solver named gradient algorithm and finite element method assuming different values for roughness values. In order to compare the results, equivalent friction factors based on these two resistance equations were required to be used. In this regard, several methods for computing equivalent roughness values were selected from the ...
Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2020
Although many explicit correlations have already been presented as alternatives to implicit Coleb... more Although many explicit correlations have already been presented as alternatives to implicit Colebrook-White (C-W) formula, performances of C-W-based relations in pipe network analysis have not been investigated. In this study, 56 explicit relations available in the literature were implemented in the analysis of four water distribution networks while the benchmark solution is computed considering the implicit C-W formula. In the numerical experiment, these pipe networks were solved using three different h-based methods including h-based Newton-Raphson method, finite element method, and the gradient algorithm. In each scenario, one of these explicit relations was considered in the process of analyzing water networks. According to the obtained results, 15 explicit relations face the convergence problems which were identified as unreliable equations. Moreover, 15 explicit equations, which were successfully performed in analyzing all sample networks with the closest results to that of the benchmark solution, were introduced as the most accurate ones. Moreover, as many scenarios outperform those of the outdated explicit equation used for the same purpose in professional hydraulic solvers such as EPANET and WaterGEMS, it was recommended they be replaced with one of the explicit equations with higher accuracy. Finally, the achieved results demonstrate that the equation selected for computing Darcy-Weisbach friction factor has an inevitable impact not only on the accuracy but also on the convergence of pipe network analysis.
Journal of Applied Remote Sensing, 2019
Abstract. The potential of synthetic aperture radar (SAR) interferometry was shown to study the c... more Abstract. The potential of synthetic aperture radar (SAR) interferometry was shown to study the compaction of the aquifer system in Darab plain, Iran. In so doing, two different datasets, including Envisat advanced SAR (ASAR) spanning 2010 and Sentinel-1A spanning 2016 to 2017, were applied in small baseline subset time series analysis. To estimate the subsidence in the time period for which there is no SAR data available, i.e., 2010 to 2016, the time series analysis results separately obtained from the two datasets were to be integrated using an appropriate model, which should have been fitted to both sets of results. However, as both deformation time series results were calculated taking into account a distinct temporal reference, fitting the model was not a straightforward task. Accordingly, the main attempt was to find the subsidence value corresponding to the temporal reference of Sentinel-1A time series with respect to that of Envisat ASAR. This shift value was optimally determined using a genetic algorithm so as to minimize the misfit between the model and the deformation time series corresponding to the entire period. The average value of the root mean square error estimated as the misfit between the model and the calculated time series at all pixels is 0.011 m, which is an indication of the high performance of the proposed method for modeling the deformation time series. The integration results were further used to derive the stress–strain relationships to study the storage properties of the aquifer system. The fact that the strain linearly increases along with the decrease in water level in most piezometric wells indicates that the subsidence is highly correlated with groundwater exploitation.
Water Resources Management, 2018
Determination of flow resistance in open channel flows is not only important for practical engine... more Determination of flow resistance in open channel flows is not only important for practical engineering applications but also challenging because of multiple factors involved. The literature review reveals that despite of various data-driven formulas and schemes, only classic Manning's resistance equation and Keulegan's formula have been utilized in practice. It also indicates that sole application of Artificial Intelligence (AI) models facilitates roughness estimation while they have not been used within a systematic roughness estimator scheme. In this study, a new eight-step scheme is developed to predict grain and total Manning's coefficients when grain and form roughness are the major sources of friction, respectively. The new scheme not only uses a new explicit equation for computing hydraulic radius related to bed for estimating grain roughness coefficient but also utilizes AI models named artificial neural network and genetic programming in the seventh step for estimating form roughness coefficient. It improves R 2 for estimating Manning's grain coefficient and RMSE for estimating discharge by 21% and 64% comparing with that of one of common formulas available in the literature, respectively. Moreover, the new scheme incorporating AI models significantly enhances the accuracy of estimation results for predicting roughness coefficient and discharge comparing with the new scheme using new developed empirical formula based on RMSE, MARE and R 2 criteria. The obtained improvement demonstrates that application of AI models as a part of a data-based roughness estimator scheme, like the one suggested, may considerably improve the precision of prediction results of flow resistance and discharge.
Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2016
In the present research, external validation criteria and uncertainty analysis are conducted to p... more In the present research, external validation criteria and uncertainty analysis are conducted to predict maximum scour depth at downstream of the stilling basins using evolutionary polynomial regression (EPR) and model tree (MT) and nonlinear regression (NLR). Data sets used to develop models were collected from experimental models of stilling basins. Effective parameters on the scour depth were included those of discharge, approaching flow depth, mean flow velocity, geometric characteristics of stilling basins and physical properties of bed sediments at downstream of stilling basins. At first, MT and EPR models are implemented based on input-output data sets and result of performances for training and testing stages are evaluated. In addition, external validations and uncertainty analyses on the formulations given by EPR and MT are carried out using statistical errors functions and have absolute mean prediction errors less than that NLR technique. Finally, results of uncertainty and the prediction errors are compared with the GEP, MT, EPR and NLR models to select GEP model as a reliable model with the highest accuracy and smaller errors than other models.
Earth Surface Processes and Landforms, 2003
The objective of this experimental study was to account for the role of sediment availability and... more The objective of this experimental study was to account for the role of sediment availability and specific gravity on cluster formation and cluster geometric characteristics (spacing and size). To isolate the effects of sediment availability and specific gravity on cluster evolution, mono-sized spheres were used to simulate the cluster evolutionary cycle. Overall, twelve experimental runs were carried out in the laboratory flume. Six of these tests were performed by using glass spheres (specific gravity, SG D 2Ð58) and the other six by employing an equal combination of glass and Teflon spheres (SG D 2Ð12) of the same diameter to evaluate the role of specific gravity on cluster evolution. The three sediment availability conditions that were investigated here simulated isolated gravel elements, pool-riffle sequences and densely packed gravel-bed. An advanced image analysis technique was employed to track the evolution of cluster microforms and provide quantitative information about the size and shape of clusters and the number of clusters per unit area. The results of this study showed that: (1) sediment availability affects the architecture and size of cluster microforms; and (2) clusters consisting of mono-sized sediments start disintegrating at twice the incipient conditions. By performing complementary tests for the isolated gravel elements case, it was found that the evolutionary cycle of individual clusters could be described as follows, in order of increasing stress: no cluster ! two particle cluster ! comet ! triangle ! rhomboid ! break up.
Iranian Journal of Science and Technology, Transactions of Civil Engineering
Coastal Engineering Journal
The rate of nitrate adsorption by a nitrate selective ion exchange resin was investigated in a we... more The rate of nitrate adsorption by a nitrate selective ion exchange resin was investigated in a well-stirred batch experiments. The kinetic experimental data were simulated with diffusion models including external mass transfer, particle diffusion and chemical adsorption. Particle pore volume diffusion and particle surface diffusion were taken into consideration separately and simultaneously in the modeling. The model equations were solved numerically using the Crank-Nicholson scheme. An optimization technique was employed to optimize the model parameters. All nitrate concentration decay data were well described with the all diffusion models. The results indicated that the kinetic process is initially controlled by external mass transfer and then by particle diffusion. The external mass transfer coefficient and the coefficients of pore volume diffusion and surface diffusion in all experiments were close to each other with the average value of 8.3×10-3 cm/S for external mass transfer ...
In recent years, new techniques for solving complex problems in engineering are proposed. One of ... more In recent years, new techniques for solving complex problems in engineering are proposed. One of these techniques is JPSO algorithm. With innovative changes in the nature of the jump algorithm JPSO, it is possible to construct a graph-based solution with a new algorithm called G-JPSO. In this paper, a new algorithm to solve the optimal control problem Fletcher-Powell and optimal control of pumps in water distribution network was evaluated. Optimal control of pumps comprise of optimum timetable operation (status on and off) for each of the pumps at the desired time interval. Maximum number of status on and off for each pumps imposed to the objective function as another constraint. To determine the optimal operation of pumps, a model-based optimization-simulation algorithm was developed based on G-JPSO and JPSO algorithms. The proposed algorithm results were compared well with the ant colony algorithm, genetic and JPSO results. This shows the robustness of proposed algorithm in findin...
Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2021
Mixture of industrial and municipal wastewater causes an increase in concentration of heavy metal... more Mixture of industrial and municipal wastewater causes an increase in concentration of heavy metals in wastewater and sludge. Sludge can be recycled to vermicompost. Heavy metal concentration of resulting vermicompost is important, as they are being used in green spaces, where irrigation disperses heavy metals into the underground water resources and affect the quality of underground water. We study concentration of iron and lead in substrate and worm tissues over time and depth in batch reactors. Two bins of 40 × 40 × 120 cm 3 (length × width × depth) are built and filled with sludge (T1) and sludge + soil (T2). We put perforated tubes in four sides of bins and a faucet with constant flow of distilled water above each pilot to produce water flow from top to the bottom of reactors. Pilots run in two stages; with and without the presence of earthworms. To study changes in worm tissues, two bins of 30 × 30 × 30 cm 3 (length × width × depth) are built, and earthworm is then added. These bins are filled with sludge (T3) and sludge + soil (T4). Obtained results from (T1) and (T2) confirm heavy metal concentration decrease over time, but increase through depth of reactors. Presence of worms in both reactors shows decrease in concentration of heavy metals. Results obtained from (T3) and (T4) indicate reduction in concentration of lead and iron in substrate and bioaccumulation in worm body mass. TOC of substrate was decreased but TKN increased during time. Initial C/N ratio is 22.2 in pilot T3, and it is decreased to 7.4 and final pH is near 7.
Labyrinth spillway has become an appropriate choice to increase an existing spillway's capacity. ... more Labyrinth spillway has become an appropriate choice to increase an existing spillway's capacity. Thus, it is necessary to understand the hydraulic performance of labyrinth spillways/weirs. This paper numerically solves turbulent ow over labyrinth spillways/weirs and determines the discharge coe cients. Reynolds governing equations, turbulence k " model, and the Volume Of Fluid (VOF) model are numerically solved to de ne pressure, velocity, and the free surface ow pro les. The numerical results are comparable to those obtained from physical modeling with maximum 6.43% error relative to results of physical modeling. Present study indicates that numerical simulation can be used to supplement physical modeling. Thus, by using numerical solutions, the site speci cs of the spillway which are often di erent from the conditions of design curves can be investigated. Also, the e ect of di erent shapes of apex on discharge capacity of the labyrinth spillway is investigated in this study. The analyses show that labyrinth spillways with round apex shape are the most e cient spillways. Numerical determination of free water surface is presented and discussed, which is helpful for optimum design of stilling basin and leading walls.
Scientia Iranica, 2013
A hybrid numerical model is introduced for simulation of cohesive sediments concentration profile... more A hybrid numerical model is introduced for simulation of cohesive sediments concentration profiles in a surf zone. For this purpose, wave height reduction must be considered, due to muddy beds and wave breaking. Models, such as Sanford and Maa’s erosion model, Krone’s sedimentation model, Tajima’s wave breaking model and the visco-elastic–plastic rheological model, are used to investigate the interaction of wave and bed and to predict the concentration profile. A splitting algorithm has been used to split the three-dimensional advection–diffusion equation into a horizontal, two-dimensional equation, and a vertical, one-dimensional equation, due to different length scales. The one-dimensional equation is discretized over a non uniform grid, and, then solved implicitly using the QUICKEST scheme (third order in time and space). The two-dimensional equation is divided into two parts (advection and diffusion) and each part is separately solved at different time steps. A suitable mesh, re...
Journal of Environmental Protection, 2021
The Severe Acute Respiratory Syndrome-Coronavirus Outbreak 2019 (CO-VID-19) has caused worldwide ... more The Severe Acute Respiratory Syndrome-Coronavirus Outbreak 2019 (CO-VID-19) has caused worldwide concern and has affected all aspects of human life. The study objective is to assess and evaluate the direct and indirect positive and negative environmental effects of COVID-19 in urban areas. Collected data for Iran as a case study is presented, comprehensively completing the dynamic effect of COVID-19 on the environment. The analysis results indicate that despite the temporarily positive effects of coronavirus on the environment, such as improvement in air quality (15%-20% reduction of NO2 in Tehran), environmental noise reduction, cleaner beach and coastal areas due to implementing lockdowns, there are negative short-and long-term effects such as excessive water consumption (10%-40% increase in Iranian cities), reduce in waste recycling and significant increase in both residential and medical solid waste generation (10%-77% increase in medical waste generation and 10%-50% increase residential waste generation in Iranian cities), which leads to pollution or/and degradation of the environment (air, water and land). Moreover, with the global economic relaunching relaunch in most countries in the coming months, it could result in adverse effects such as increase in the greenhouse gas emissions. Assessment of environmental impacts, type and scale, could help for better planning and mitigation of the future pandemics.
Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2021
Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2021
Journal of Hazardous Materials, 2022
The present study employed an anoxic packed bed biofilm reactor (AnPBR) inoculated with in-situ b... more The present study employed an anoxic packed bed biofilm reactor (AnPBR) inoculated with in-situ biosurfactant-producing bacteria for the biodegradation of petroleum wastewater. Highly acclimated biomass decreased the start-up phase period and with increasing the initial total petroleum hydrocarbon (TPH) concentration from 1.5 to 4 g/L was accompanied by TPH and chemical oxygen demand (COD) removal efficiencies of above 99% and 96%, respectively. Decreasing hydraulic retention time (HRT) from 24 to 6 h caused an increase in the specific hydrocarbon utilization rate value from 0.45 to 1.66 gTPH/gbiomass.d. Moreover, dehydrogenase activity, surfactin, and rhamnolipid reached 31.8 μgTF/gbiomass.d, 95.1, and 27.1 mg/L, respectively. The biodegradation kinetic coefficients such as K, Ks, Kd, Y and µmax were 0.784 (d-1), 0.005 (g/L), 0.138 (d-1), 0.569 (gVSS/gCOD), and 0.446 (d-1), respectively. Dropping of bioreactor performance, especially TPH removal efficiency from 99% to 37.6% in the absence of nitrate after 10 days, indicates anoxic metabolism has been the dominant biodegradation pathway. The effluent chromatogram of gas chromatography/flame ionization detector (GC/FID) showed aliphatic, cyclic aliphatic, and aromatic hydrocarbons efficiently degraded. According to the high degradation rate of AnPBR in different operational parameters, it can be recommended for the treatment of oil-contaminated wastewater.
Scientia Iranica, 2021
Lattice Boltzmann method (LBM) has emerged as a fast, precise, and efficient numerical solution t... more Lattice Boltzmann method (LBM) has emerged as a fast, precise, and efficient numerical solution to solve differential equations. There seems to be a dearth of research regarding the solution for groundwater flow in unconfined aquifer using LBM. Accordingly, in this study, an innovative numerical solution based on LBM was introduced to solve groundwater flow in unconfined aquifers, taking into account D2Q9 scheme. The solutions obtained from the proposed LBM were compared to results stemmed from three different unconfined groundwater problems with known solutions. Both steady and transient conditions for groundwater flow were considered in simulations. It was deduced that the proposed LBM could simulate the unconfined groundwater flow satisfactorily.
Applied Ocean Research, 2021
Abstract Shorelines around the world are of great importance because of their role in people'... more Abstract Shorelines around the world are of great importance because of their role in people's lives. Therefore, understanding its behavior seems to be vital. Shoreline changes and its realignments are highly nonlinear and finding a method in such a way that it could model its patterns would be very useful. ANN's are popular methods, as they have been applied to numerous problems. In this study, recurrent ANNs such as NARNET and NARXNET are used to model the shoreline changes in Narrabeen Coast, Australia, between 1980 and 2014. Their outputs represent a reliable performance for predicting shoreline changes based on historical data. These results also are compared with other methods, including RBF, GRNN, and TDNN. The NARNET showed most accurate results with MAPE= 17.18%, and the NARXNET had the best correlation with CC=0.26. It has been indicated that the NARNET and NARXNET are better methods since they need less extra data, besides the shoreline position itself.