A. Cifci, Y. Uyaroglu, S. Birbas. Direct Field Oriented Controller Applied to Observe Its Advantages over Scalar Control // Electronics and Electrical Engineering.-Kaunas: Technologija, 2012.-No. 3(119).-P. 15-18. A new squirrel cage induction motor (IM) model, which is based on the state model in d-q coordinate system, is proposed so that it is available for direct field oriented control (FOC), which is of rotor flux oriented type, or vector control. Then, using the IM model, field oriented and scalar speed controllers are designed in Simulink environment. MATLAB figures have been used to visualize the simulation results of either control principles. Ill. 6, bibl. 14 (in English; abstracts in English and Lithuanian).

Energy demand management is particularly important for developing and emerging economies. Their energy consumptions increase significantly, depending on their growing economies. As a result of Turkey's rapid economic and population growth, electricity consumption is increasing. Electricity consumption forecasting plays an essential role for energy suppliers, consumers, and policy makers. Therefore, using models to accurately and reliably forecast future electricity consumption trends is a key issue for the planning and operation of electric power systems. This paper focused on forecasting electrical energy consumption by utilizing deep learning methods, i.e., Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU) models, for time series data. One-hour and three-hour ahead forecasting are accomplished by using a historical dataset of electrical energy consumption in Turkey. The comparison results show that the GRU model is slightly better than that of the LSTM. Our study also reveals that one-hour ahead predictions are more accurate than three-hour ahead predictions.

Electromagnetic interference produced by high-speed electrical and electronic systems (i.e., base stations, mobile phones, radar, television and radio transmitters) that facilitate daily life also caused a pollution to be dealtwith as a part of daily life. Increasing use of electronic devices arising from the rapid developments in science and technology increased electromagnetic interference in electronic devices well besides the electromagnetic pollution in the environment. Therefore, there is a tremendous need to develop effective protection against the negative effects of electromagnetic interference. The objective of this paper is to make the composite boards from the recycling of Tetra Pak packages and to investigate the effect of aluminum additive on absorption efficiency of electromagnetic interference at various frequencies. Experimental results showed that as the ratio of aluminum additive rate in the composite material increased, the attenuation ratio increased.

Electronics devices that facilitate our daily life are rapidly reaching into almost every area of our lives nowadays. Wireless communication using electromagnetic waves is preferred rather than wired communication due to the physical hardship in communication of these devices with each other. Electromagnetic waves provide communication between transmitter and receiver and also reach to unintended targets except receiver. If electromagnetic wave reaches an electronics circuit, it will cause the formation of undesired parasitic currents and the destruction of electronic circuits defined as electromagnetic interference. If electromagnetic wave reaches the tissue environment, it will change the structure and arrangement of cells at the molecular level depending on the wave frequency and power. As a result of long term exposure, it may cause cancer and its derivatives in living organism due to changes in cell structure. As seen in the electromagnetic studies, it may cause irreversible damage to living organism exposed to electromagnetic waves. Therefore, the study carried out will have an effect especially protection of living species against the electromagnetic wavelength's harmful effects. In this study, it is aimed to be performed of the mineral doped waste paper-based board design which will absorb electromagnetic waves that imposed nowadays in any environment. Experimental results show that electromagnetic shielding effectiveness of waste paper fibers with mineral powders (BaSO4, C, Fe2O3) is acceptable levels.

ÖzMekanik özellikler malzemelerin dayanımını ve kullanım alanlarını belirleyen en önemli etkenlerdir. Bir ağaç malzemenin hangi malzeme grubunda olduğu ve hangi ağaç türü olduğu mekanik özelliklerine bakılarak bilinebilmektedir. Bu çalışmada ticareti yapılan kızılağaç (Alnus glutinosa subsp. Barbata), doğu kayını (Fagus orientalis Lipsky), karakavak (Populus nigra), ceviz (Juglans regia), meşe (Quercus robur), kestane (Castena sativa), sedir (Cedrus libani) ve çam (Pinus) gibi önemli bazı ağaç türlerinin mekanik özellikleri yapay sinir ağları ile modellenmiştir. Bu çalışma, herhangi bir konstrüksiyon için ihtiyaç duyulan mekanik özellikleri karşılayacak ideal ağaç malzemenin tespitinde yardımcı olacaktır. Böylece bilimsel çalışmalarda ve ticarette ağaç türü ile ilgili sınıflandırmalar daha etkin bir şekilde yapılabilecektir.Anahtar kelimeler: Ağaç türleri, Mekanik özellikler, Yapay sinir ağları AbstractThe mechanical properties are the most important factors determining the strength and usage areas of materials. It can be known from the mechanical properties that a wood material of which material group is in and which wood species it is. In this study, the mechanical properties of some important wood species such as alder (Alnus glutinosa subsp. Barbata), oriental beech (Fagus orientalis Lipsky), black poplar (Populus nigra), walnut (Juglans regia), oak (Quercus robur), chestnut (Castena sativa), cedar (Cedrus libani) and pine (Pinus) were modelled by using artificial neural networks. This study will assist in the determination of ideal wood material that meets the mechanical properties required for any construction. Thus, classifications related to wood species can be made more effectively in scientific studies and in trade.

ÖzBu çalışmada mineral madde olarak ısıl ve yalıtım amaçlı kullanıma sahip olan vermikülit, sert poliüretan malzemeye eklenerek iki ayrı ahşap kompozit malzemenin yüzey kaplamasında kullanılmıştır. Vermikülit toplam poliüretan kütlesine %5 ve %10 oranında eklenmiştir. Çalışmada ahşap kompozit malzeme olarak orta yoğunlukta lif levha (Medium Density Fiberboard -MDF) ve kontrplak (Plywood) kullanılmıştır. Sert poliüretan ile yüzeyleri kaplanan ahşap kompozit malzemelerin yanma davranışı TS EN ISO 11925-2 standardına göre tek kaynaklı alev testi ile kütle kaybı ve ısıl geçirgenlik değerleri DIN 4102 ve TS EN 13823 standardına göre incelenmiştir. Ayrıca malzemelerin yüzey sertlikleri ve elektromanyatik ekranlama özellikleri belirlenmiştir. Deneysel sonuçlara bakıldığında yüzeyi poliüretan ile kaplanmış ahşap kompozitlerde vermikülit katkısının her iki malzemenin yanma direncine olumlu katkı yaptığı belirlenmiştir. Yüzey sertliği kontraplak malzemlerde iyi sonuçlar verirken kütle kaybı ve ısıl geçirgenlik değerinin MDF malzemelerde daha iyi sonuçlar verdiği belirlenmiştir. Deneylerde ölçüm yapılan frekanslarda ağırlıkça katkılama oranı arttıkça elektromanyetik ekranlama özelliğinin artığı görülmüştür.

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VOLTAGE STABILITY ANALYSIS BASED ON ENERGY FUNCTION OF AN ELECTRICAL POWER SYSTEM WITH AND WITHOUT SVC Ahmet Çifci, Yılmaz UyaroğluPreliminary notes This paper presents a study based on the variable gradient method for the construction of a Lyapunov (energy) function. The single-machine infinite-bus (SMIB) power system with and without static VAR compensator (SVC) is considered. Voltage stability analysis is studied on both power systems. The performance of SVC on voltage stability of the system is shown and numerical simulations are compared with each other. Additionally, it is demonstrated that the stored energy density is an indicator of the closeness of the operating point to the instability region of the system. The simulation results for the studied models are obtained by using MATHCAD software. Keywords: Lyapunov (energy) function; single-machine infinite-bus power system; static VAR compensator; variable gradient method; voltage stabilityAnaliza stabilnosti napona na temelju funkcije energije u elektroenergetskom sustavu sa i bez SVC Prethodno priopećenje U ovom se radu opisuje analiza temeljena na metodi promjenjivog gradijenta za tvorbu Lyapunove funkcije (energije). Razmatra se energetski sustav neograničene sabirnice stroja -SMIB (Single Machine Infinite Bus) sa i bez statičkog VAR kompenzatora (SVC). Analiza stabilnosti napona provedena je na oba energetska sustava. Pokazan je rad SVC kod stabilnog napona sustava i numeričke su simulacije uspoređene jedna s drugom. Dodatno je pokazano da je gustoća pohranjene energije pokazatelj blizine točke u kojoj će doći do nestabilnosti sustava. Rezultati simulacije za analizirane modele dobiveni su primjenom MATHCAD softvera.