مقالات رزومه بابک امین نژاد

Shear force is one of the most important influencing forces of structural beams and especially unreinforced deep concrete beams that cause sudden failure and sudden collapse of the structure and for this reason, it is of interest to designers and implementers of structures. The study of the conducted research shows that the proposed methods including the use of artificial neural network cannot predict Provide an accurate description of the behavior of deep reinforced concrete beams against shear force. This research, while specifying the cause of the error of the artificial neural network in estimating the shear strength of deep reinforced concrete beams, presents a solution to achieve accurate results by optimizing the artificial neural network by the meta-heuristic algorithm of particle swarm. For this purpose, 309 laboratory samples of deep concrete beams were collected from the research literature and the particle swarm algorithm was used to optimize the weights in the artificial neural network using MATLAB software. The comparison of the results of this method with the results of these letters and other existing methods that were examined in this research showed that the use of the combination of particle swarm algorithm and optimized artificial neural network to estimate the shear strength of unreinforced deep reinforced concrete beams provides more accurate answers.

The project portfolio is to transfer the strategic needs of the organization to projects and operational activities. If portfolio risk occurs, it can affect the portfolio success metrics and overshadow the achievement of the organization's strategic goals. Despite the important role of portfolio risk management in the success of an organization, no proper analysis of project portfolio risks has been provided yet. The purpose of this study is to investigate the importance of portfolio risks and, selection of the best portfolio risk management strategy using multi-criteria decision-making methods. Due to the ignorance of portfolio level risks, the first step of this research is to identify and select important portfolio risks of projects based on previous studies in this field. The importance of risks in different portfolio management strategies was then assessed using a questionnaire from a group of elites. In this study, the CRITIC method, which is a multi-criteria decision-making method has been used to determine the weight of each risk, during which the importance of each risk is calculated without direct questions from experts, and only using the scores given to each risk in different strategies. After that, different portfolio risk management strategies will be identified and, the best risk management response will be calculated and selected.

Evaporation and Transpiration (including soil water evaporation and transpiration in plants) account for about 60% of the annual atmospheric precipitation on the earth. This process is the backbone of the hydrological cycle and a key element in Water Resources Management and the agricultural sector. The Soil and Water Assessment Tool (SWAT) and the Surface Energy Balance Algorithm for Land (SEBAL) are specialized models that address this problem. A SEBAL model is a tool for estimating the spatial distribution of actual evaporation and transpiration using satellite images such as MODIS, and Landsat 8. Although Landsat 8 images have a higher Spatioal resolution than MODIS images (30 m vs. 1000 m), their Tempoural resolution is lower than that of MODIS images (every 16 days vs. every day). On the other hand, daily MODIS images may not always be usable because of problems such as cloudiness. In addition, the interpretation of numerous satellite images is very time-consuming. In the current study, the evaporation and transpiration values in the catchment area of Karun River were obtained in three dry, normal and wet years (2019, 2020, 2021) using the recalibrated SWAT model based on runoff and crop yield and the SEBAL algorithm. Then the results of the SEBAL algorithm and SWAT model were compared with each other based on the water year conditions. In the second stage of the research, the results of the SEBAL algorithm and the range of changes of the main parameters of this algorithm in the plains of Ahvaz-Mlathani and Al-Baji basins were presented according to the ground data and using the MODIS images from the Terra satellite with a suitable time resolution and OLI sensor from Landsat8 satellite, which has a good spatial resolution.

The use of hydrological models in watersheds has always been of interest to water resources researchers. Hydrological simulation models are valuable tools for investigating challenging issues related to watershed management, such as the effect of climate change on water resources and the effect of urbanization on floods and droughts. Spatial distribution hydrological model WetSpa is used to simulate river flow at basin scale. The model uses the observed topography, land use, soil map, and daily meteorological time series (rainfall, evaporation and temperature) to predict hydrographs and distributional-spatial hydrological parameters of the basin. In this article, the object-oriented, modular and process-oriented model of WetSpa, which is prepared based on the flexible modeling approach, is applied to simulate the daily hydrograph in Khorramabad basin.

The inputs of the model include digital elevation maps, soil type, land use, and time series of precipitation, temperature, and potential evaporation and transpiration, which are from the statistics of 6 meteorological stations in a ten-year period (water year 84-85 until 93-94) is used. After preparing the inputs of the model, at first the maps of the distribution parameters are automatically generated in the map format by the GIS pre-processing component of the model. After that, the model is calibrated using a 5-year statistical period (water year 84-85 to 89-88) of precipitation, temperature, and potential evaporation and transpiration data. The model uses Thiessen polygons to apply precipitation, temperature, and evaporation data. For this purpose, the daily discharges of Jam Anjir hydrometric station located at the outlet of the studied watershed are used. Model calibration is done manually by determining the values of 11 global (general) parameters of the model, so that the best match between simulation and observational hydrograph is obtained. And finally, the validation of the model is carried out based on a 5-year statistical period (water year 89-88 to 94-93) and the values of the global parameters obtained in the calibration stage.

The maps of distributed parameters are produced, which after preparing the inputs of Mashdand's production model showed that the average potential runoff coefficient of the area is 63% and the concentration time of the area is 17 hours. In the following, according to the 11 global parameters, which symbol and range of changes are specified in table (3), the model global (general) parameters values  are obtained in the calibration stage. Comparing the simulated hydrograph by the model and the observed hydrograph in the calibration stage shows that the best match between the observed and simulated data is established with a correlation coefficient of 0.39. Validation of the model is also based on a 5-year statistical period (water year 89-88 to 94-93) and the values of global parameters. The output files of the model illustrate that 26.15% of the precipitation becomes runoff during the calibration period. During the validation period, the share of total runoff from precipitation is 26.42%. Moreover, the simulation results of the model demonstrate the ratio of evaporation to precipitation in the calibration and validation periods is 57.18 and 69.20%, respectively. Additionally, the results of the evaluation of the model based on the Kling-Gupta index (KGE) present the value of 0.68 for the calibration period and 0.74 for the validation period.

In this article, the effectiveness of WetSpa model is investigated in order to simulate the daily flow of Khorram Abad River at Cham Anjir hydrometric station. According to the results obtained from this research, it can be said that the Wetspa spatial distribution model has the ability to simulate the hydrological behavior of the basin with acceptable accuracy. The graphical comparison of the calculated and observed hydrographs for the calibration and evaluation period also shows a relatively good match between the two hydrographs. Examining the results of calculating of the water balance components by the model demonstrates that the outflow in the calibration and validation period accounted for 26.15 and 26.42% of the total precipitation respectively, seems logical considering the major land use of mountains and pastures in the irrigation basin.

Pre-sedimentation basins are considered as the major and important components in water treatment process through conventional method. Because of the high cost of constructing these basins, which is approximately 30% of the total costs of water treatment plants, modeling and optimum performance of pre-sedimentation basins are very important. In pre-sedimentation basins, because of the existence of velocity gradients, secondary and rotational flows occur. In order to increase the performance of a pre-sedimentation basin (clarifier), it is essential to have a uniform and calm flow field. The use of suitable baffle configurations may help forming favorable flow field and increase the efficiency of the pre-sedimentation basins. In order to find the proper position of a baffle in a rectangular sedimentation basin, computational investigations are performed. The first step to optimize pre-sedimentation basin is accurate calculation of the velocity field and the volume of rotation zones. Flow guiding blades can also be used to depreciate the inlet jet and reduce turbulent kinetic energy. Because of the flow complexity and also the effects of scale, physical models can not solely provide a clear understanding of the physics governing the flow field and it is necessary to study this phenomenon numerically along with field and experimental studies. The first step to optimize pre-sedimentation basins is accurate simulation of the velocity field and the volume of rotation zones. In the present study, numerical simulation of flow was investigated in a pre-sedimentation basin using SSIIM and Fluent models. Continuity and momentum equations were solved using finite volume method. Flow analysis was done steady by the SIMPLE algorithm for velocity and pressure coupling. Discrete method of continuity equations, momentum, turbulent kinetic energy, Reynolds stress drop and discretion of pressure equation are standard. The numerical results were calibrated with experimental results of Shahrokhi et al. (2011) and Imam et al. (1984). Flow simulation was performed in 3D and flow velocity profiles were compared with the experimental results in different sections of a pre-sedimentation basin. Then, in order to sedimentation investigation in the pre-sedimentation basin, advection and dispersion equation of sediment concentration was solved simultaneously with the governing equations of flow. The results of the vertical distribution of sediment concentration profiles in different sections of the basin were compared with the experimental and numerical results of other researchers. Finally, the effect of flow guiding blades on the flow pattern and the efficiency of sedimentation in the pre-sedimentation ponds were investigated. The comparison showed that there is a good agreement between numerical and experimental study with an average error of 6%. Flow rate is one of the effective parameters on creating a rotational zone inside the basins. With increasing the inlet flow rate from 0.002 to 0.01 cubic meters per second, the length of the rotational zone has increased 25% and the width of the rotating zone has increased 45%. The secondary and rotational currents formed at the entrance of the basin are two small rotational zones and approaching the middle of the basin and formation of flow separation zones, the number of rotating areas and their dimensions have increased. From the beginning to the middle of the basin, the shear stress is increased. In the sections x = 0.46 m and x = 0.82 m, the amount of shear stress is maximum. Amount of energy in the middle of the depth has decreased by 40% compared to the water level and about 60% compared to the floor of the sedimentation basin. It showed that there is a good agreement between the numerical and experimental results. It also indicated high ability of SSIIM in predicting distribution of sediment concentration profiles in pre-sedimentation basins. With increasing flow depth, the sediment concentration decreases. In the section x = 1.58 m, the sediment concentration near the free surface is 44 mg L-1, which decreased by 57.48% compared to the concentration of sediment in the basin bed. In the case without the guide blade, near the free surface of the stream, the sediment concentration was decreased. Also, in the middle of the basin, due to the turbulence of the flow and the rotational areas, the secondary current strength was maximal and decreased as it approached the end of the basin.

The main idea of developing green buildings is based on the construction of environmentally friendly buildings and energy conservation and sustainable development. Although the concept of green building alone can open the way to achieve such goals, a mechanism for its implementation must also be provided. Therefore, identifying and evaluating the necessary incentives for the development of green buildings has a key role. The main goal of this paper is to evaluate the effectiveness of the incentive measures (policies) influenced on the promotion of green buildings. By reviewing and summarizing the results of the research literature to identify relevant policies in the field of green construction based on different phases of the project's life cycle, a database consisting of 6 major goals and 42 incentive actions (policies) effective on the promotion of green buildings was identified. By developing the comprehensive fuzzy evaluation method and forming the policy-action matrix, policies and policies were evaluated in the direction of further development of green buildings. The results showed that regulatory measures play an important role in all five phases of the life cycle of green buildings. However, it should not be overlooked that due to the obstacles created by regulatory policies for the future green building market, these policies may not be the best approach for green building development. Incentive measures such as financial incentives for the decision-making stage of development, improvement of technical standards and evaluation system, and conversion to an integrated design model in the market and technology are ranked higher than regulatory policies. The results of the present research provide a clear understanding of the adoption of effective incentive policies on the promotion of green buildings.

Accurate data about runoff in the future in a watershed facilitates managers' decisions in water-related decisions and helps conserve natural resources for sustainable development. The two factors of cost and exact time are directly related to accurate runoff estimation. Using computer models to simulate natural phenomena such as the hydrological cycle is one way to reduce costs and increase accuracy.

The information for this research was obtained through the SWAT model website and global data. This study evaluates the accuracy of different calibration and validation methods in the hydrological simulation of Qarasu watershed, the SWAT (hydrological model) and a comparison between GLUE and PSO methods with the SUFI-2 method were used to calibrate the SWAT model. For simulation, 13 specific parameters were selected in all methods in the same situation. It should be noted that the data required for this research were collected from (SWAT model website) and (Water Resources Management Company).

All three methods were able to simulate runoff with acceptable R2 and NSE results (above 0.7), and the sensitivity analysis showed that Sol_K, CH_N2 and CN2 were more sensitive than other parameters.

Although the SUFI-2, PSO, and GLUE algorithms can reduce the difference between the observed and simulated data, the performance of the SUFI-2 algorithm in runoff simulation is more accurate than other algorithms. Therefore, it is suggested to use this algorithm to predict runoff.

One of the most important concerns of the drilling industry is reducing the negative impacts of drilling cuttings of oil-gas wells. The increasing growth of the oil industry and drilling of oil and gas wells led to large amounts of drilling waste. In this study, drilling cuttings in concrete as a substitute for part of the cement used in the construction industry has been investigated. In this study, the possibility of using drilling cuttings of formations of Bangistan group, including siltstone and sandstone, in concrete production has been evaluated as a substitute for part of the cement in concrete. For this purpose, laboratory studies have been conducted to quantify the compressive strength of concrete samples. The optimum use of drilling cuttings is 25%, which it reduces the total strength of concrete samples by 34%. In addition, the effect of air ash and silica fume additives on improving the compressive strength of concrete samples containing drilling cuttings has been investigated. The test results showed that the addition of these materials had a significant effect on increasing the compressive strength of concrete samples containing 25% of drilling cuttings so that the lost compressive strength is reduced from 34% to less than 2%.

The present paper aimed to develop a bridge management system using a combination of new fuzzy multi-criteria decision making methods. The developed system consists of a three-phase protocol. In the first phase, using past studies, personal intuitions and judgments and experts' experiences, a database containing critical factors affecting the critical condition of bridges was prepared, as well as identifying a number of urban overpass bridges in Tehran city with relatively similar characteristics and in need of maintenance. In the second and third phases, considering the uncertainties in the decision-making problem, by combining Delphi-SWARA-ARAS methods in a fuzzy environment, while screening and prioritizing more efficient and effective critical factors, the critical situation was assessed and the steps studied were selected. The results of Fuzzy SWARA method to determine the effective final factors showed that the factors of seam filling and discontinuity of the bridge related to the main structural index, average and duration of maximum annual rainfall at the bridge location of the main index of climate and hydrology, drainage, water discharge Surface and insulation of the bridge from the main index of safety, proximity and convenience of bridge access to adjacent arterial roads in terms of the main index of strategic (regional) importance, cost-benefit ratio for maintenance or reconstruction and replacement of the bridge from the main budget index and finally The volume of traffic passing over the bridge has gained higher ranks than the main index of traffic and pavement, respectively. Also, the results of Fuzzy ARAS method based on final critical factors (18 factors) showed that among the 24 bridges, Sheikh Fazlollah-SattarKhan, Hakim-Sheikh Baha'i, Hemmat-Africa, Lashkari-Aircraft industries bridges And Resalat-Haqqani with usefulness of 3.226, 3.171, 3.081, 3.080 and 3.077, respectively, are considered as the most preferred bridges in terms of the need for maintenance allocation.

The most important goal in the planning and optimal operation of the reservoir system is to determine the various operating policies that can operate properly Under the drought condition and existing uncertainties. In this study, a combination of the Horse herd optimization algorithm (HOA) and WEAP simulator model was used to extract the optimal reservoir exploitation policies in the form of specific optimization and objective functions were calculated based on the results of the implementation of each scenario and the total operating period for Maroon and Jarreh reservoir dams. The results showed that the average error of the optimal rules extracted from the support vector machines relative to the output of the HOA algorithm in the validation stage is less than 17%, which indicates the high efficiency of this method in predicting the optimal pattern of the dam control curve in real-time. Moreover, evaluation of different scenarios showed that agricultural development in areas 1, 4, and 5 of Ramhormoz will be reduced by an average of 50% and also a 10% reduction in inflow to Marun and Jarreh dams will have negative effects on Shadegan wetland.

The present study was carried out to investigate the quantitative and qualitative status of water resources in Varamin plain and to provide suitable management strategies for sustainability and outflow from current and future challenges in this area. Therefore, statistics and the necessary data were gathered and used WEAP software to provide appropriate management solutions for the impact of the continuation of current water resources policies in the region over the next20 years, by considering the population growth. The results showed that if the current status of water resources continues, we have to harvest more of the surface water resources to cover the increased drinking water demand, based on the increasing population of this area. So that this overdrawn would reach about a 10.8Million cubic meters in 2035. Also, the average annual no coverage of agricultural and industrial demand in the year 2035was 76 and 23 million cubic meters, respectively, 16/2 and 27/4 percent. This overdrawn could reflect the adverse effects on the Mamlu dam, increase in the ground subsidence and increase other economic- social issues. So that, it causes to reduce the average annual volume of the aquifer to around 35 million cubic meters and a 1centimeter daily average drop in the aquifer during the 20-year period. Therefore, due to the high evaporation rate in the region, using artificial feeding methods, such as reducing the amount of evaporation, is a solution to compensate for some of the water shortages in some areas. Therefore, collecting surface water, feeding water underground, and proper water management, using modern water management practices is some of the most important factors in water resource management.

Cement protector sheath as a factor of durability and stability in oil and gas wellbore structure plays a vital role in the continuous sustainable production from hydrocarbon reservoirs. In order to enhance the mechanical properties of cement protector sheath, this research has focused on the use of carbon nanotubes due to their proven excellent mechanical properties. Although this idea has previously been an exciting topic for research in the development of cement and concrete, In this regard, as research innovation, to overcome the non-uniform distribution challenges of organic carbon nanotubes in the cement aqueous base medium, an advanced technique for making emulsion nano polymers was handled to disperse the nanoparticle cores in the polymer matrix. According to the findings of this work, carbon nanotubes disperse effectively in polymer emulsions, and polymer latex disperses well in the aqueous base of cement, allowing for a wide dispersion of nanoparticles to benefit from their maximal surface performance and mechanical properties. Non-agglomeration of nanoparticles in the cement structure has led to the use of the highest reactive and physical surface of these nanoparticles, which has significantly strengthened the mechanical properties of cement mass after hardening. The experimental results significantly increase the Young modulus to 580% From 4.12 GPa for the benchmark sample compared to 28 GPa for the modified sample with 4%W of the nanopolymer. The optimized samples in slurry form also provide good rheological properties for pumping capability and sufficient hydrostatic pressure to control the wellbore pressure.

Water is the most important issue for the survival of all people in the society. The smallest disruption in the water supply in people's lives and livelihoods brings the greatest threat to life. However, the interweaving of water issues (major problems and threats) and national security is one of the most important problems of governance in the new era. Building a strategic vision to turn threats into opportunities in these two areas is one of the requirements of good governance. By understanding the issues in the field of water resources and how it is related to the issues raised in the field of national security, this essay is trying to provide a strategic view with the aim of turning these threats into new opportunities. Reducing the negative effects of climate change requires knowing the power and capacity of water resources. This research tries to improve and optimize the methods and modify the structure of intellectual engineering to solve the problems caused by it in the field of water. In this research, the issue is investigated using geomorphological evidence and climatic heritage. This research can be categorized as theoretical-practical in terms of its purpose.

Evaporation is one of the wasteful methods of water resources in geographical areas and is of special importance in the study of water resources.

In the present study, databases including Chah Nimeh dam evaporation data and large-scale network data have been prepared. The SDSM model is used to simulate the evaporation of the coming decades under three scenarios: RCP2.6, RCP4.5 and RCP8.5. The basic modeling period is from 1983 to 2005 (23 years)

Comparison of evaporation estimates for the next two time periods and under different scenarios showed that for the time period 2100-2080 scenarios RCP2.6 and RCP8.5 estimated higher values for evaporation. Examination of inputs showed that air temperature, geopotential height and wind indices have the greatest impact on the evaporation of wells in Sistan.

The results of this study showed that the rate of evaporation in the period of increasing 2100-2080 will experience more than 300 mm per year. The greatest increase in evaporation will be in the warm period of the year.

The leakage is one of the main challenges in the operation of water distribution networks. In the present study, leakage location is detected using Feedforward Artificial Neural Networks (ANNs). For this purpose, two scenarios are considered for training the ANNs. In the first scenario, two simultaneous leakages with equal values, and in the second scenario, two simultaneous leakages but with unequal values are applied to every pair of network node. The training data are analyzed by EPANET2.0 hydraulic simulation software linked with the MATLAB programming language. In both scenarios, first, ANNs are trained using flow rates of total pipes number. Then, sensitivity analysis is performed by Hybrid ANNs for the flow rates of different percent of pipes number. The results of the proposed Hybrid ANNs indicate that in the first scenario, by having the flow rates of 10% of the total pipes, the locations of two simultaneous leakages are successfully determined. However, for the second scenario, while the difference between the two leakages is less than 80% of the maximum leakage (up to ratio value of 10 and 90 % leakages), by having the flow rates of 10% of the total pipes, the locations of the two leakages are still successfully determined. But for larger differences, only the location of the bigger leakage can be detected. Despite the complexities of the second scenario, the proposed ANNs could successfully detect the location of the bigger leakage.

Sustainable production from hydrocarbon resources is very important in economic stability, maintaining production capacity, and fulfilling the export commitments of governments in providing energy sources from hydrocarbon fuels. Drilling and completing oil and gas wells in the safest and most efficient manner is possible in order to meet sustainable production objectives from oil and gas reserves. One of the threats to sustainable production from oil and gas reservoirs is the wellbore integrity failure and missing isolation for various underground layers from the inner space of the well. Alternatively, the leakage of gas and saltwater from the liner lap or casing shoe due to the micro-annulus phenomenon at the margin of the cement bond is another threat to oil and gas wells. To fulfill the aims of separating subsurface layers and directing the appropriate flow of hydrocarbon fluid to the production duct, the cement sheath acts as a sealing barrier against formation layers with varying fluid content and pore pressure. Cement slurry is pumped to the annular space after driving the steel casing. Improving the properties of cement structures is a continuous technical-engineering effort to increase the durability of structures and prevent the destruction or occurrence of problems related to weakness in these structures. Cement design requirements for oil and gas wells are accompanied by perfect sealing of the well. This research seeks to provide an efficient solution to cover the gas and fluid migration issues due to cement sealing inefficiency. Combining the superior rheological properties of latexes in cement with the strength properties of silica nanoparticles is an idea that has been developed in this research. In experiments, the effect of silica nanoparticles on improving the compressive strength of cement, reducing porosity, and effective permeability in gas migration has been well established. Polymer latex also helps cement slurry by developing thixotropic properties in the slurry and reducing the transient time window to minimize the gas migration possibility in critical times when the cement column is not able to effectively resist the formation fluids and restrict the opportunity for formation fluid invasion.

Open communication between people working in the construction industry has led to the creation of a new complexity in the interactions. In order to solve the safety issue, in addition to the necessity of examining the problem itself, it is indispensable to examine the related issues as much as possible. The construction workshops are complex systems of human resources whose core is extensive patterns between formal and informal relations. The proper understanding of construction project managers about the influence of informal network relations on the performance of formal relations leads to the suitable exploitation of limited resources in construction workshops and ultimately helps to increase productivity. The results of this research in a construction workshop in Tehran, Iran, showed that almost all factors had a pivotal role and centrality as much as the desired occupation based on a workshop chart in the formal network relations; but communication between people is formed based on personality, racial, linguistic and other characteristics in the informal network relations. These relationships by casting a shadow on formal relations lead to a failure to achieve safety objectives and instructions. Therefore, the existence of ethnic and cultural links between the project manager and the Health and Safety Executive (HSE) with other employees at the workshop will increase productivity in the workshop safety.

The satellite-based precipitation products are one of the sources of rainfall estimation. Nonetheless, for usage in the local regions and, or for parameterizing of meteorological and hydrological models at basin scales, their spatial resolution is often coarse. Therefore, in this study, a downscaling– calibration method was developed for global precipitation measurement (GPM) satellite estimates (at 0.1° spatial resolution), for one year from 01/04/2014 to 31/03/2015, by considering the spatial heterogeneity of the relationship between precipitation and the environmental variables using the mixed geographically weighted regression (MGWR) model for Golestan province. In obtaining improved precipitation data with 1 km spatial resolution at an annual scale, the results showed that (1) the proposed method not only improved the spatial resolution of precipitation but also increased accuracy; (2) the downscaled and calibrated precipitation data (CC = 0.74, bias = 0.23) performed better than the original data (CC = 0.58, bias = 0.35) against ground observations.

Transient flow in a pressurized pipe system is an intermediate state flow that arises between one constant flow and another. In other words, whenever the flow conditions change from a steady-state due to any deliberate or accidental disturbance, a transient flow is created in the pipeline (Chaudhry, 2014). This phenomenon is one of the most severe cases of damage in pressurized pipelines.In many previous studies related to transient flow analysis, the pipe wall has been made of metal and concrete materials with elastic mechanical behavior. In recent years, the increasing use of plastic pipes (such as polyethylene and PVC) has led to the development of mechanical models of transient flow, taking into account the viscoelastic behavior of these materials.In recent years, polymer pipes such as polyethylene and PVC, due to their technical and economic advantages over other pipes such as steel, cast iron, concrete, and asbestos, have increased day by day. This makes the need to understand the structural behavior and hydraulic performance of polymer pipes even more urgent. The modeling method of polymer pipes for transient flows analysis has several fundamental differences from non-polymer pipes. These differences are mainly related to the interaction of fluid fluctuations with the characteristics of pipe wall structures. Polymers generally exhibit viscoelastic mechanical behavior that affects the intensity, formation, and damping of pressure fluctuations in transient currents. In these equations, it is usually assumed that the pipe wall is made of concrete and metal and has a linear elastic behavior. In comparison, polymer pipes have inelastic behavior.The present study aims to investigate the pressure response of viscoelastic pipeline under transient flow. For this purpose, first, the pressure signal's initial peak and the effects of line packing are investigated. The effect of the transient valve's closing time in different flows on the pressure signal is investigated in the following. Another important issue is the overpressure. In this research, laboratory values of overpressure are compared with the theoretically calculated values.

The laboratory model of this research was designed and built in the hydraulic laboratory of the Faculty of Water Engineering, Shahid Chamran University of Ahvaz, to evaluate the response of the viscoelastic pipeline system under transient flow. The pipes are high-density polyethylene (HDPE) (SDR11, PE100, NP16) with a length of 158 meters, an inner diameter of 5.05 cm, and a thickness of 6.5 mm. According to the four stages of waterhammer, if the constant pressure of the pipeline is low, the pressure signal in the third stage, after returning from the tank and reaching the transient flow valve, enters pressures less than the vapor pressure of the fluid, and due to the column separation. This phenomenon reduces the pressure signal capability to detect other system malfunctions. To avoid this problem, a pressurized reservoir was used as the upstream boundary condition at the pipe system's upper boundary.

The initial peak pressure due to the effects of friction and fluid inertia and the delayed deformation of the pipe wall is completely weakened in the first period of the pressure wave and does not exist in subsequent periods. The transient flow signal analysis showed that the classical waterhammer equation could not predict the observed maximum transient pressure of fast transient in polyethylene pipe. The calculation of the wave speed in polyethylene pipes based on the modulus of static elasticity is significantly less than that of elasticity's dynamic modulus. As the valve's closing time increases, their maximum pressure peaks and pressure drop gradients decrease, and this peak gradually weakens and disappears. In addition, depending on the time difference between closing the valve, the pressure wave will have a time delay. The results showed that a significant energy drop with phase change in the pressure wave is observed in all measurement locations.

After quickly closing the transient valve, a significant pressure peak is observed, followed by a sudden drop in the pressure signal. At a constant flow, the initial peak pressure decreases with increasing valve closing time. Suppose the calculations are based on the modulus of elasticity provided by the factory. Even if the elastic tube is assumed, the amount of overpressure is 16.6 to 37.65% less than the actual value.This is an important reason to consider polymer pipes' viscoelastic behavior by precision transient flow hydraulic models or to consider the dynamic modulus of elasticity, sometimes up to twice the static modulus of elasticity proposed by manufacturers, in the design phase.

Implementation of various infrastructure projects is one of the most important factors in the economic development of the countries. In recent years, due to the growing population and economic development of developing countries, there is a strong need for infrastructure development in many countries. One of the most important aspects of developing and developing construction projects is the financing of projects that play the most important role in project development and achievement of predetermined goals. For this purpose, in the present study, a case study of freeway projects in Iran has been conducted and semi-structured interviews with experts and experts on public-private partnership contracts in the country. For this purpose, in the first step, identifying and screening risks from the viewpoint of experts in public-private partnership contracts and introducing risk assessment criteria, then the grading weights grading analysis method was used to obtain the weight of the criteria. Finally, the final ranking of the risks of public-private partnership contracts has been taken into account, taking into account the results of the initial steps, using a comprehensive fit assessment approach. The results show that low-quality material and equipment risks, stakeholder resistance to approval, and lack of realistic goals are of great importance. The proposed framework can help stakeholders in public-private partnership agreements in developing countries to better manage the risks of public-private partnership contracts.

Infrastructure and development projects in any country constitute the infrastructure and development of that country. In the implementation of these projects, financing is an important and primary concern due to the lack of infrastructure and infrastructure in the country on the one hand and the lack of capital resources on the other hand, capital has an undeniable role in this. Financing projects is one of the most common investment methods in any country. Undoubtedly, how and how to finance the projects for each level of existing institutions depends on the nature of the project. Paying attention to financing has a high share in solving the problems of financing and launching projects. Therefore, the purpose of this study is to rank the methods of financing from external sources in construction projects. The present study is applied in terms of purpose and descriptive-survey in terms of the nature of the method. In order to collect data, a questionnaire based on multi-criteria decision making method (network analysis method) was used, which was completed by five senior financial engineering experts with at least 10 years of experience in financing projects of construction companies in the west of Tehran. The collected data were analyzed by Super Decisions software. The results of financing ranking showed that international loans with a relative weight of 0.314 ranked first, BOT contracts with a relative weight of 0.21 and finance with a relative weight of 0.171 took second and third place. Findings of the study show that in general, the criterion of higher rate of return with a relative weight of 0.64 than the criteria of lower risk with a relative weight of 0.26 and a ceiling of more funds with a relative weight of 0.1 is of higher importance in financing from external sources in the project. Have civil engineering and should be given more attention.

Groundwater plays an important role in the sustainable development of human societies. The rapid growth of population, low level effectiveness, and performance of irrigation in agriculture sector have led to increase in demand for water resources in Iran. Therefore, the regional management of water extraction and the optimal usage of available water resources are highly important. Considering the urgent and intense need for groundwater resources, we used Shannon’s entropy and frequency ratio models to identify the groundwater resources of Sero Plain for agricultural and drinking purposes as well as to detect the factors that affect occurrence of groundwater and zoning.