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Abstract

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 (V dc) regulation to have minimum variation during dynamic conditions and to generate an accurate loss component of current (i Loss). The accurate iLoss, 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.

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Egy modern finnugor építészet felé •

Vargha László Finnországgal kapcsolatos munkássága

Toward a Finno-Ugric Architecture •

László Vargha’s Scholarly Activities Related to Finland
Építés - Építészettudomány
Author: Laczó Dániel

Vargha Lászlóban (1904–1984) az utókor elsősorban a néprajztudóst tiszteli, jóllehet szakmai pályája kiterjedt a muzeológiára és az építészettörténetre is. E három tudományterülettel életszakaszonként eltérő mértékben foglalkozott. Tevékenységét mindhárom diszciplína esetében áthatotta a finnek építészete iránti érdeklődés. Cikkemben életútját e szempontból vizsgálom, felhasználva a Szentendrei Szabadtéri Néprajzi Múzeumban őrzött archívumát.

Fiatalkorának meghatározó élmenyei kötődnek a finnekhez. Személyes visszaemlékezése alapján Vargha a finn építészettel és művészettel gyermekkorában ismerkedett meg egy magyar folyóiratban. Pályakezdőként csereprogrammal jut el Finnországba és köt barátságot finnekkel. A második világháború idején közreműködik egy finnugor kiállítás összeállításában Budapesten és Kolozsvárott. Mindeközben gyűjti és jegyzeteli a finn néprajzi szakirodalmat.

A háborút követően a nemzetközi kapcsolattartás lehetőségei szűkülnek, Vargha is csak később tér viszsza a finn kultúrához. A hatvanas években a helyszínen tanulmányozza a szabadtéri néprajzi gyűjteményeket – köztük számos északit –, melynek tanulságaival hozzájárul a Szentendrei Szabadtéri Néprajzi Múzeum – svéd szóval: a skanzen – létrejöttéhez. Oktatóként az egyetemi órákon is tanítja a kortárs finn építészetet. Előadásokon, kiállításokon mutatja be itthon Finnország építészetével kapcsolatos ismereteit. Emellett szakmailag legkiemelkedőbb fellépései a finnugor kongresszusokhoz köthetők, melyekben visszatér egy őt korábban is foglalkoztató témakörhöz; melynek értelmében a magyar népi építészetnek létezik egy ősi, finnugor rétege. Sikereit árnyalja, hogy pályája végén több jelentős publikációs lehetőséggel nem élt.

Egyéb érdemei mellett Vargha László kiemelkedő alakja a finn–magyar kulturális kapcsolatoknak, a finnekkel kapcsolatos kiemelkedő munkássága pedig önálló fejezettel gazdagíthatja pályája értékelését.

László Vargha (1904–1984) is considered a prominent ethnographer in Hungary, albeit he was active in museology and history of architecture as well. During his career he had shifted between these topics. His contribution to all three disciplines was affected with a profound interest in Finnish art and architecture. My article investigates his professional career in the light of his appeal, using the sources preserved in his personal archive in the Hungarian Open-Air Museum.

Vargha had determinative experience related to Finland during his youth. His first encounter with Finnish art was in the pages of a Hungarian periodical in his childhood. In an exchange programme he visited Finland and made friends with his peers. During the Second World War he contributed to an exhibition on Finno-Ugric peoples. The archives reveal that he had studied Finnish ethnographic literature in this period.

Possibilities for maintaining international relationships were reduced after the fall of the Iron Curtain. Vargha returned to Finnish culture only after a significant interval. In the sixties he conducted a study trip to various open-air museums. Many of those destinations were in Sweden and Finland. The study trip contributed to the foundation of the Hungarian Open-Air Museum, which still borrows its name in Hungarian from the Nordic Museum: skanzen. As a university lecturer he introduced Finnish architecture to the curriculum.

Vargha presented Finnish architecture in lectures and exhibitions across Hungary. He also participated in the International Congress for Finno-Ugric Studies, where he revisited the concept that an archaic Finno-Ugric layer is present in Hungarian vernacular architecture. Despite the possibilities offered and his thorough knowledge he failed to publish significant publications at the end of his career.

Apart from his other achievements László Vargha was also an important character in the relationship of Finnish and Hungarian architecture, and his outstanding oeuvre related to Finland could enrich his professional evaluation.

Open access
Pollack Periodica
Authors: Farid Boushaba, Salah Daoudi, Ahmed Yachouti, and Youssef Regad

Abstract

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.

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Abstract

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.

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Abstract

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.

Open access

Abstract

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.

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Abstract

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.

Open access

Abstract

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.

Open access

Abstract

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.

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Abstract

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.

Open access