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Long-term variation of hourly air temperature obtained from Open Weather, Romania, was analysed in the center of Bucharest city, over a period of 40 years (1980-2020). A computer program to extract summer heatwaves within the study period was written. Analysing the results an extreme heatwave scenario has been defined within the context of climate change and urban influence, to be used in future air and water temperature models.

Daily variation of Danube River temperature measured at Oltenitț gauging station over 9 years (2008-2016) was analysed in comparison with the air temperature measured by satellite in the same location between 1979-2020. Air temperature shows a nearly 2°C increase over the 40-years period, which can be attributed to both climate warming and anthropic impact. Water temperature was modeled with a sinusoidal function and variation with discharge was discussed. Long-term trend of hourly surface air temperature variation was obtained from Open Weather data. Air - water temperature dependency was fitted with a logistic function with good approximation. Resulting correlations help predict water temperature as a function of satellite - measured air temperature.

The objective of the paper is to compare the hydrologic and hydraulic reservoir routing methods in term of assumptions, equations, numerical computation procedures, necessary data and advantages-disadvantages of their use. To test the results provided by the two methods, a set of two reservoirs from Romania was chosen: one long and narrow and the other one roundly shaped. Corresponding inflow hydrographs were chosen, and similar conditions were imposed for the outflow dam control structures, namely the initial water level in the reservoir to be at the Spillway Crest Level (SCL) and no outflow control. For the hydrologic method the Puls procedure was used and a program was written in Scilab to solve the continuity equation in finite differences. For the hydraulic method HEC-RAS software was used to solve the 1D Saint-Venant equations. Outflow and stage hydrographs at the dam were compared together with the stage hydrograph at the reservoir tail for the hydraulic method. Results show that the hydraulic method should be used for the long and narrow reservoirs, as it considers the backwater effect, whereas the hydrologic method can be efficiently used for all other reservoirs where this effect is negligible.

The main objective of the paper is to simulate the steady state flow conditions along the regulated Damboviţa River in Bucharest City. The canal has 11 reaches in series separated by control structures with gated weirs (barrages). The simulations are performed using the 1D HEC-RAS software for flows between 3 and 45 m3/s, in order to find the optimal opening of each set of gates, so that water levels along reaches are kept at the target Normal Pool Levels (NPL) elevation. For the determined operating situations optimized gate openings and gates' rating curves are drawn. The computed water surface profiles for the maximum flow allow for checking if the banks are flooded, whereas velocity values for the minimum, ecological flow of 3 m3/s highlight the reaches over which the biota could be affected during summer drought periods. This model could assist the Water Management Authority's technical staff to better operate the gates in an integrated manner. Since currently gate operations are individually performed at each control structure, such a model would be a primary step in designing and implementing an automatic controlling system for the entire Damboviţa canal in Bucharest City.

The study evaluates the energy engineering students' perception and insights concerning the use and usefulness of AR technology in online engineering education during COVID-19 pandemic. The assessment is based on the following criteria: usefulness, suitability, advantages for different activities, types of overlays. Results show an increased interest for AR applications in all types of teaching activities, and its usefulness for a better understanding of studied topics. Among the most important advantages of using AR are considered closer connection to practice, speeding and deepening learning. Overall, these results indicate an improved user perception of AR from acceptance to high interest. [ABSTRACT FROM AUTHOR]

The overall objective of this paper is to propose a viable approach to quality Education in Power Engineering during the COVID-19 period. To this end, we base the study on our previous steps in implementing Augmented Reality technology for training future engineers in the field of energy. To cope with the present challenges brought by the COVID-19 pandemic, we analyzed the necessary paradigm shift to maintain the benefits of using Augmented Reality in teaching. [ABSTRACT FROM AUTHOR]

The paper presents a method of sediment gradation using the Basegrain software to analyse pictures taken from the bed surface in 20 locations along the upper course of Prahova River, Romania. Sediment grading curves and median diameter, median diameter (d50) values for each sample, obtained by the virtual sieving method were compared with the ones obtained through the Wolman - pebble-count method along a shorter reach. Results show a good match between the two methods. [ABSTRACT FROM AUTHOR]

The paper presents the results obtained from a subsurface sediment grain size analysis along the upper, gravel-bed, Prahova River, Romania. Samples were taken from 20 locations over a 56 km study reach and were subsequently sieved and weighted in the laboratory. Both d50 and d84 characteristic diameters were plotted against distance and an overall downstream coarsening was identified. Considering the natural and anthropic context of the studied reach, hypotheses to explain this trend were launched. [ABSTRACT FROM AUTHOR]

The paper investigates the degree of measurement accuracy of several sharp - crested weirs of different shapes, based on the experimental results obtained in the laboratory. A sensitivity analysis is performed to assess the influence the weir shape has on the coefficients of discharge and to identify which one provides the best accuracy for measuring small discharges. [ABSTRACT FROM AUTHOR]

The purpose of the study is to reveal changes of the hydrodynamics and sediment transport induced into the river channel by the operation of small hydropower plants (SHPs). A 36-km reach of the upper Prahova River in Romania has been chosen, along which 10 run-ofriver developments are built. A 1D modeling software was used to compute hydrodynamic parameters over the selected reach. Two discharge scenarios were considered into the channel: (1) mean annual flow (for the natural regime, without SHPs), and (2) the minimum discharge (worst case scenario of SHP operation for the environment). Results of the second scenario show that ecologically relevant hydraulic parameters in the channel are approaching the thresholds of endangering the fish habitat. On average, depth and shear stress drop by 50%, mean velocity by 40%, and flow area by 75%. Comparison between computed nondimensional shear stress and its corresponding critical value indicates that minimum discharge can only transport finer particles than average from the bed surface, thus leading to potential filling of fish spawning areas with sand. [ABSTRACT FROM AUTHOR]