Authors:Mukul Chankaya, Aijaz Ahmad, and Ikhlaq Hussain
This paper presents a tree growth optimization based control of a grid-tied dual-stage photovoltaic system. The tree growth optimization has been employed for optimizing the proportional and integral controller gains for direct current bus voltage (Vdc) regulation to have minimum variation during dynamic conditions and to generate an accurate loss component of current (iLoss). The accurate , further enhance the control's performance by generating the accurate reference currents. The presented system is simulated and analyzed in a MATLAB simulation environment under various dynamic conditions, i.e., irradiation variation, unbalanced and abnormal grid voltage. The overall performance is satisfactory as per IEEE 519 standards.
Authors:Farid Boushaba, Salah Daoudi, Ahmed Yachouti, and Youssef Regad
This paper presents numerical solvers, based on the finite volume method. This scheme solves dam break problems on the dry bottom in 2D configuration. The difficulty of the simulation of this type of problem lies in the propagation of shocks on the dry bottom. The equation model used is the shallow water equations written in conservative form. The scheme used is second order in space and time. The method is modified to treat dry bottoms. The validity of the method is demonstrated over the dam break example. A comparison with finite elements shows the weakness and robustness of each method.
Authors:Lucia Bytčanková, Ján Rumann, and Peter Dušička
Recently, the construction of shaft intake structures in Slovakia has increased. The shaft intake structures overcome significant vertical depth over short horizontal distance. The flow of water in these shaft intake structures is therefore very complicated. The velocity field at a shaft intake of a small hydropower plant was investigated on a physical model in a hydraulic laboratory using the particle image velocimetry method. The particle image velocimetry measurements were realized for different shaft depths and the results of this study can increase negative effects of not suitable the design of construction on the flow homogeneity in the turbine intake.
In this paper a complete methodology of modeling and control of quad-rotor aircraft is exposed. In fact, a PD on-line optimized Neural Networks Approach (PD-NN) is developed and applied to control the attitude of a quad-rotor that is evolving in hostile environment with wind gust disturbances and should maintain its position despite of these troubles. Whereas PD classical controllers are dedicated for the positions, altitude and speed control. The main objective of this work is to develop a smart Self-Tuning PD controller for attitude angles control, based on neural networks capable of controlling the quad-rotor for an optimized performance thus following a desired trajectory. Many problems could arise if the quad-rotor is evolving in hostile environments presenting irregular troubles such as wind gusts modeled and applied to the overall system. The quad-rotor has to rapidly achieve tasks while guaranteeing stability and precision and must behave quickly with regards to decision making fronting turbulences. This technique offers some advantages over conventional control methods such as PD controllers. Simulation results are achieved with the use of Matlab/Simulink environment and are established on a comparative study between PD and PD-NN controllers founded on wind disturbances application. These obstacles are applied with numerous degrees of strength to test the quad-rotor comportment. Experimental results are reached with the use of the V-REP environment with which some trajectories are tracked and then applied on a BLADE Inductrix FPV+. These simulations and experimental results are acceptable and have confirmed the efficiency of the proposed PD-NN approach. In fact, this controller has fairly smaller errors than the PD controller and has an improved ability to reject troubles. Moreover, it has confirmed to be extremely vigorous and efficient fronting disturbances in the form of wind disturbances.
Authors:Lea Čubanová, Andrej Šoltész, and Jakub Mydla
The paper deals with an analysis of a drought in the small basin of the Gidra River in Slovakia due to problems with the abstraction of water from small reservoirs and ponds. A detailed hydrological assessment of the M-daily discharges for a long-term period was based on a dataset from the only gauging station on the upper part of the river. Because of the existing water structures with prescribed operations during the year, hydrometric and geodetic measurements were taken by the authors. The solution to this problem represents the conditions for the minimum required Q355 discharge in the river anytime and anywhere. This can only be solved with a master operational manual for the whole river to be able to flexibly react to the current hydrological situation.
In the sorting plant examined during the research, the sorting of the selectively collected mixed packaging waste is done by hand. Studies were performed on the quantitative changes of the waste stream entering and leaving the sorting plant, the composition properties according to the particle size, and lastly the number of pickings. The amount of incoming waste has increased linearly over the years. The sizes preferred by the optical separators were the guideline during the measurements. Sixty percentage of all incoming waste falls in the ideal range of 70–350 mm, 20% in the range of <70 mm and 20% in the range of >350 mm. Because there are significant differences in composition and quantities as the seasons and months alternate, these results provide important information for engineers designing a mechanized technology.
The deteriorative processes occurring in the environment, the growth of population, the water demand of industry and agriculture, point out day after day the increasing role of water management. The economical use of drinking-water consumption as well as the cost reduction is becoming more and more important. In this research, the measure of a water supplier of Győr was examined in terms of implementing the purposes above.
Authors:El Kabira El Mjabber, Abdellatif Khamlichi, and Abdellah El Hajjaji
Advanced control of variable speed horizontal wind turbine was considered in the high wind speed range. The aims of control in this region are to limit and stabilize the rotor speed and electrical power to their nominal values, while reducing the fatigue loads acting on the structure. A new nonlinear technique based on combination between sliding mode control and radial basis function neural network control was investigated. The proposed hybrid controller was implemented via MATLAB on a simplified two masses numerical model of wind turbine. By applying the Lyapunov approach, this controller was shown to ensure stability. It was found also to be robust and able to reject the uncertainties associated to system nonlinearities. The obtained results were compared with those provided by an existing controller.
Authors:Maysam Shmlls, Dávid Bozsaky, and Tamás Horváth
Cement replacement materials are commonly used in concrete technology. Several researchers have examined high-performance concrete after adding mineral admixtures to it, but further studies are still needed to provide the optimum dosage of these materials for instance fly ash and silica fume. This study compares three types of concrete and the mechanical properties (compressive strength, flexural strength, and splitting tensile) of these types at the age of 28 and 90 days. The test results designate that adding the mineral admixtures commonly affects the mechanical properties of all the tested types. However, silica fume is more operative than fly ash. Furthermore, adding the fly ash and silica fume in the same concrete type slightly improves the mechanical properties.
Contact with groundwater in the disposal geological site will induce the creation of an amorphous corrosion layer on the high-level radioactive glass. This is connected to silicate saturation conditions in the surrounding medium, and it is influenced significantly by geochemical processes in the near-field minerals at that depth. The international simple glass is a six-oxide borosilicate glass that is commonly used in nuclear interest. It is a simple glass generated from its composition to be an international benchmark glass. The results of the standard materials characterization center leaching tests in double deionized water at 90 °C and an initial pH value of 6.3 showed that it reacts with Ankerite for a short period of time. The effect of Ankerite on borosilicate glass durability through magnesium-silicate precipitation has been investigated and confirmed in this study.