adell moradi sabzkouhi

In order to reduce the amount of evaporation from water reservoirs, various methods have been proposed, which can be divided into two physical and chemical categories. In the physical methods, by using physical coverings, such as floating balls, metal and polymer plates, or tree leaves, and by covering the water surface, evaporation waste is greatly reduced. These covers reduce a large amount of solar energy reaching the water surface and reduce vapor transmission by slowing the air flow.

The present study was conducted with the aim of investigating the effect of the coverage and shape of polypropylene sheets on reducing the evaporation rate and the effect of meteorological variables on the efficiency of these sheets efficiency. This research was carried out in two parts, in the first part, the efficiency of square and triangular polypropylene plates was investigated in comparison with floating balls, and in the second part, the efficiency of 100, 70, 50, and 30% coverage of polypropylene plates was evaluated.

The results obtained from the tests showed that in the conditions of using floating balls, the reduction of evaporation was more intense and this coating was able to reduce evaporation to a greater extent compared to square and triangular floating plates. Also, using the square and triangular polypropylene plates and floating balls reduced evaporation by 30.71%, 14.86% and 48.7%, respectively, compared to the control pan.

The results of two-way ANOVA on different meteorological variables showed that the percentage of relative humidity, which was the most important factor in evaporation from the pan, lost its significance due to the presence of floating balls and polypropylene sheets on the water surface. The comparison of rectangular covers with different densities showed that by increasing the density from 30, 50 and 70% to 100% respectively, evaporation decreases by 2.3, 1.5 and 0.8 times.

Because heavy metals can build up within the bodies of living things, and because of chemical reactions, they can become poisonous and carcinogenic. Among other things, heavy metal-containing salts are one way these elements enter the body. In Khuzestan Province, Iran, the Shorbarik River is one of the most significant rivers from which salt is mined. In order to assess the health and quality of the salt taken from the Shorbarik River in accordance with national regulations, this study looked into the concentration of heavy metals (lead and cadmium) in these salts. The Shorbarik River was the study region, and the surface salts of the dried bed were sampled in four stages. After drying in an oven, they were injected with acid into an atomic absorption device. Due to the high concentration of cadmium in the region's salts, the risk of cancer from exposure to heavy metals through salt consumption is serious. Ecologically, the Shorbarik River's salt is generally low in lead contamination and considerably high in cadmium contamination, with high levels in the spring and summer. Therefore, it is recommended to consume refined salt.

The occurrence of phenomena such as surges in complex devices such as turbines, and problems caused by neglecting safety precautions, may result in significant economic damage and losses to the transmission system. On the other hand, electricity production is a key factor in the economic and social development for developing countries. Recently, institutions involved in electricity supply have recommended pump as turbine projects as hydroelectric power plant for supplying electricity to rural areas due to their economic benefits. The issue under investigation in this study is the effect of pump shutdown on surge occurrence and its effects on the water transmission line.

The case study project is the water transmission line to the city of Masjed Soleyman located in the northeast of Khuzestan province, Iran. In this study, by using WaterGEMS software, the route of the transmission line, the type and diameter of the pipes, pressure relief valves, tanks, etc., have been defined and modeled in steady state. After processing the line in steady state, in order to investigate the replacement of the PATs with pressure relief valves and its shut-down effect on the water hammer phenomenon created in the transmission line, the model created in WaterGEMS is called in the Bentley HAMMER CONNECT software to analyze the unsteady state condition. The phenomenon of surge has been investigated in three scenarios as follows: The first scenario involves studying the flow conditions in a steady state without any changes in the transmission line. The second scenario involves replacing the pressure relief valve at kilometer 054+0 from the Tang-e Mo reservoir with a reverse pump. The third scenario involves replacing the pressure relief valve at kilometer 700+3 from the Tang-e Mo reservoir with a reverse pump.

When the pressure relief valves are working, the flow velocity in the pressure relief valve in 3+700 km, equivalent to 2.07 m/s, and the pressure before the pressure relief valve is equal to 157.7 meters of water and reaches 20 meters of water. Also, in the pressure relief valve 0+054 km from the reservoir, the speed is 2.1 m/s and the pressure decreases from 104.77 m to 13.2 m of water, respectively. For second scenario, in the first pressure relief valve, 91 meters of pressure is wasted. In this case, the PATs with turbine flow and pressure have replaced the existing pressure relief valves. The inlet and outlet valves of the first PAT are closed in 20 seconds and the flow through it is reduced to zero. Third scenario considers the water hammer impact resulting from shutdown of the PAT (at 3+700 km) on the transmission line. 137 meters of pressure is wasted in the second pressure relief valve. Also, the flow through it is 580.189 liters per second. In this case, the inlet and outlet valves of the PAT are closed in 20 seconds. It is necessary to explain that if the valves of the PAT (at 3+700 km) are closed, the downstream flow will also decrease; But due to the bypass of the PAT, the input flow to the downstream pumps does not reach zero and the pumps do not exit the circuit.

The results indicate that the occurrence of the surge due to the failure of the PAT(s) installed in the transmission line, despite the creation of positive and negative pressure waves in the transmission line, does not cause serious disturbance in the pipeline. It is also concluded that the thickness of the steel material selected for the pipeline has the required strength to withstand the maximum and minimum pressures.

Rivers are one of the most important water sources that play an important role in providing water needed for various activities such as agriculture, industry, drinking and electricity production. Many of the water resources planning in the countries are based on the potential of surface water resources. Therefore, knowledge of the quality of water resources is one of the important requirements in planning and developing water resources and their protection and control. Used water considering the importance of the Shurbarik River for the use of the people of the surrounding villages, in this study, the water quality of the Shurbarik River was determined using water quality parameters. In order to achieve the objectives of this study, the parameters of dissolved oxygen, pH, biologically required oxygen, chemically required oxygen, temperature, phosphate, nitrate, ammonium, turbidity, total dissolved solids and electrical conductivity were investigated in four seasons. Based on the average NSFWQI index, the water quality of Shobarik River is in the bad quality category. The range of this index is between 29.9 to 35.4 in all seasons. The average of this index is the lowest in summer and the highest in winter. Based on the average IRWQISC index, the water quality of Shobarik River is in the bad quality category. The results related to the value of the Liou index also show that the numerical value of this index is in the range of 3.25-4.25, which indicates the relatively polluted quality of water from the point of view of this index in all seasons. Contrary to the differences in the parameters and methods used to calculate the indicators, the results of all methods are consistent and are very useful for evaluating water quality.

To investigate the main and interactive effects of various meteorological parameters on the rate of evaporation from the water surface, variance analysis was used. Based on the analysis, all the mentioned parameters had a significant effect on the rate of evaporation. Eta squared for the main effects was 0.69, indicating that the main effects could estimate 69% of the output variance. Based on this parameter, the amount of solar radiation had the most significant effect on the rate of evaporation, followed by surface pressure and relative humidity. The results of variance analysis considering the interactive effects showed that all the interactive effects had a significant effect on the rate of evaporation, and only the interactive effect of wind speed and radiation was not significantly different. The interactive effect of surface pressure on temperature and radiation had the most significant effect on the rate of evaporation, followed by the interactive effect of temperature and relative humidity. Investigation the effect of various meteorological parameters on the rate of evaporation from the water surface and their interactive effects can be used to investigate the efficiency of various methods to reduce evaporation.

The rapid population growth and urban development have notably influenced the role of water distribution networks (WDNs) compared to the past. This issue encourages operators to adopt new smart tools to better system management. Such a smart system is expected to play an effective role in both crisis and normal services. For fire extinguishing services, a WDN needs to be well-equipped to supply the fire flow efficiently. In this sense, WDNs are required not only modern fire-fighting equipment but also a systematic program to satisfy the fire demand in the right place at the right time. This paper aims at introducing a pre-processing (not real-time) approach for smart pressure management using the regulation of control valves. The problem is formulated as a mathematical programing in which the reliability measure is maximized and the valve opening positions are decision variables. Using a self-adaptive Genetic Algorithm coupled with EPANET, the problem is solved. The proposed algorithm is applied to a case study from the literature and produces the optimum pattern for regulation of valves. Such results can be an appropriate guide for operators to practically maneuver valves in fire situation. The case study manifests that by applying the model the reliability of system can be increased up to 40.7%.

Hydraulic analysis of pipe networks is generally done considering certain values for independent parameters of the system such as roughness of pipes, nodal demands, etc. Such analysis would inevitably lead to certain hydraulic responses of the system, i.e. nodal pressures, etc. This is while, inherent uncertainties associated with independent parameters as expected stresses, spread over the system and result in hydraulic stress in nodal pressure heads as dependent uncertainties. Using optimization tools, this study presents a reliable approach based on interval analysis to deal with these uncertain hydraulic stresses. In the proposed approach, the optimization problem is formulated in a manner that the nodal demands, roughness of pipes and water levels in elevated tanks would be the decision variables while extreme nodal pressures for unknown intervals are explored as the objectives functions. The large number of junctions in the case of real pipe networks, leads to inefficient iterative use of single objective optimization engine. In order to this problem, this study exploits a many-objective approach with an appropriate performance. Applying the proposed approach on a real pipe network shows that ±15% variation in nodal demands and pipes’ roughness in addition to ±1m in water levels might produce hydraulic stress in pressure heads from -13.7% to +10.2% with regard to the crisp values. In such a condition, it is possible for 125 junctions out of 128, to fail in satisfying the minimum required pressure head. It is demonstrated that the proposed approach has acceptable accuracy for analyzing hydraulic stress in real water distribution networks.