رضا فرزاد

Evaporation from lakes and reservoirs of dams as well as soil is one of the most important processes in hydrological engineering. One of the procedures required for proper and effective management of reservoirs, water resources, basin stability, and agricultural operations is the accurate prediction of evaporation. Weather phenomena that are non-stationary, unpredictable, and non-linear generally have an impact on evaporation. It is evident that these issues hinder the development of precise prediction models. Evaporation is a natural process based on energy supply and air exchange, during which molecules and atoms find the necessary energy to leave the liquid phase and enter the gas phase. On the other hand, climate changes can affect the evaporation parameter, so the prediction of evaporation from the reservoirs of dams is vital in the discussion of water resources management

This investigation uses the SVR-ABC, Wavelet-SVR, and SVM models with six wavelet functions to predict the amount of evaporation from the Dez dam reservoir in Khuzestan province, Iran. The data series from 1350–1396 for 46 years arises from the Dez dam meteorological station in Iran. The study also uses precipitation, maximum temperature, minimum temperature, average temperature, absolute maximum temperature, and absolute minimum temperature and Using the findings of Shannon's entropy, 5 parameters Tmax, Tmin, Tave, Tamax, Tamin are divided into 5 groups with 1 parameter, 2 parameters, 3 parameters, 4 parameters and 5 parameters respectively as the most effective parameters for scenario planning, which in total 28 scenarios are studied.

According to modeling results based on RMSE, MAE and WI evaluation indices show that the performance of SVR-ABC meta-heuristic model with RMSE=82.219, MAE=53.977 and WI=0.815 is better than Wavelet-SVR model with RMSE=93.637, MAE= 69.360 and WI=0.762. Additionally, based on the violin diagram, the single SVR model with periodic and non-periodic inputs estimated the monthly evaporation lower than the observed values, and as a result, the average data has decreased compared to the observed values.

Furthermore, according to the results of the six wavelet functions that were used in the study, the Wavelet-SVR axis decomposition model with the Haar wavelet function at decomposition level 1 and values of 93.637 mm/month, 69.360 mm/month, and 0.762, respectively, shows the most appropriate result among the six wavelet functions based on the RMSE, MAE, and WI evaluation indices.

The purpose of this research is to reduce cement consumption by replacing nano fly ash (NFA) in the concrete mixture and increase the compressive strength of concrete by strengthening the interfacial transition zone (ITZ). Thus, four proportions of NFA with values of 0.1, 0.5, 1 and 5% by weight were selected in the concrete mixture and the compressive strength of concrete was evaluated within 7 and 28 days. A scanning electron microscope (SEM) equipped with an X-ray energy diffraction spectrometer (EDS) was used to detect the compounds resulting from the reaction between particles. Based on the results, in the sample containing 1% NFA (optimal sample), compared to the samples without NFA, the 7-day compressive strength of concrete increases by 97% and the 28-day compressive strength increases by 61%; which shows the NFA has a better performance in increasing the strength of concrete at early ages. Also, the amount of water absorption in the sample containing 1% NFA decreased to 33%, therefore, the permeability of concrete against destructive agents is improved. These results show that the interfacial transition zone (ITZ), which is the weakest link in the concrete chain and the limiting factor of concrete strength, is strengthened in the presence of NFA, and leads to an increase in durability and compressive strength of concrete.

Local scouring is one of the most important phenomena and factors in the destruction of the bridge bridges, which was studied in order to reduce the destructive effects of this phenomenon using the experimental model and the effect of the combined stone and chipping of the submerged plates in this study. In this research, a laboratory model of a cylindrical base group of 5 cm in diameter and a stone of china with grains of 1, 1.5 and 2.5 cm in diameter, and submerged plates in numbers (2, 4 and 6) of a plate of 10 × 15 in a flume An experimental laboratory and a landing number (0.25, 0.22 / 0.20 / 0.2) were tested and analyzed. The main objective of this study was to investigate the combined effect of Chinese stone and submerged panels on reducing the scour depth of the group The bridge is a cylindrical bridge and, using Buckingham's dimensional analysis, the parameters The results of this study showed that by increasing the diameter of the stone and the number of submerged plates, the percentage of the depth of water washed to the diameter of the base was significantly reduced. Which was found to be the highest for bases 1, 2, 3 (69%, 72%, 74%) and the lowest values (49%, 50%, 57%), which showed that by increasing the flow rate of erosion Also increased.