Overcoming hurdles: Challenges in testing and validating wind turbine transformers with electronic tap changers

Grid codes are technical requirements and standards that govern electrical grids, ensuring reliability and safety. These codes have evolved to accommodate changes in technology, policy, and environmental concerns. With increasing penetration of renewable energy sources such as wind power, grid codes have become more demanding. Compliance with grid codes is crucial for wind turbine manufacturers; power plants must withstand voltage transients and operate within specified limits. Grid stability is an additional challenge where available connection points do not meet requirements. To address these challenges, Siemens Gamesa is conducting a technology development project called FASTAP, meaning “fast tap” change, funded by the European Union’s Horizon 2020 program under grant agreement No 971145. This project focuses on developing Dry-Type Transformers (DTT) and Oil-Immersed Transformers (OIT) with Electronic Tap Changers (ETC) to enhance Wind Turbine Generator (WTG) capabilities and support grid compliance. Potential benefits are cost savings and improved performance, especially for weak grids

Desarrollo y validación de una escala para evaluar la frecuencia de uso de herramientas y métodos de evaluación en el aula para profesores de matemáticas

The purpose of this study was to develop a scale to assess the frequency of using classroom assessment tools and methods for mathematics teachers. This study was conducted on 320 Turkish mathematics teachers. The data were analysed using the SPSS 17.0 and LISREL 8.8 statistical software packages. EFA and CFA, item-total correlations, and convergent and discriminant validities were used to assess the construct validity. EFA and item analysis were performed with 170 mathematics teachers. After EFA, a four-factor scale with 25 items was identified, explaining 52.38% of the variance. The CFA was carried out with 150 mathematics teachers. The first and second-order CFA results indicated that the scale model had good fit indices, and the convergent and discriminant validity of the scale was confirmed. The Cronbach's alpha and composite reliability (CR) coefficients were satisfactory. The results of this study showed that the scale is a reliable and valid instrument for assessing the frequency of mathematics teachers’ use of classroom assessment tools and methods.Este estudio tiene como objetivo el desarrollo de una escala para evaluar la frecuencia de uso de herramientas y métodos de evaluación en el aula por parte del profesoradode matemáticas. En el estudio participaron 320 profesores de matemáticas turcos. Los datos fueron analizados utilizando los paquetes de software estadístico SPSS17.0 y LISREL 8.8. Para evaluar la validez del constructo se usó el AFE y el AFC, las correlaciones ítem-total y las validaciones convergente y discriminante. El AFE y elanálisis de ítems se realizaron con 170 profesores de matemáticas. Tras el AFE, se identificó una escala de cuatro factores con 25 ítems, que explicaban el 52,38 % de lavarianza. El AFC fue llevado a cabo con 150 profesores de matemáticas. Los resultados del AFC de primer y segundo orden indicaron que el modelo de la escala presentabaadecuados índices de ajuste, y se confirmó la validez convergente y discriminante de la escala. Los coeficientes alfa de Cronbach y de fiabilidad compuesta (RC) fueron satisfactorios. Los resultados de este estudio mostraron que la escala es un instrumento fiable y válido para evaluar la frecuencia con que el profesorado de matemáticas utiliza los instrumentos y métodos de evaluación en el aula

Overcoming hurdles: Challenges in testing and validating wind turbine transformers with electronic tap changers

Grid codes are technical requirements and standards that govern electrical grids, ensuring reliability and safety. These codes have evolved to accommodate changes in technology, policy, and environmental concerns. With increasing penetration of renewable energy sources such as wind power, grid codes have become more demanding. Compliance with grid codes is crucial for wind turbine manufacturers; power plants must withstand voltage transients and operate within specified limits. Grid stability is an additional challenge where available connection points do not meet requirements. To address these challenges, Siemens Gamesa is conducting a technology development project called FASTAP, meaning “fast tap” change, funded by the European Union’s Horizon 2020 program under grant agreement No 971145. This project focuses on developing Dry-Type Transformers (DTT) and Oil-Immersed Transformers (OIT) with Electronic Tap Changers (ETC) to enhance Wind Turbine Generator (WTG) capabilities and support grid compliance. Potential benefits are cost savings and improved performance, especially for weak grids

Synthesis and structural characterization of Fe based Ti+Ni3Al+Al2O3 reinforcement composite produced by mechanical alloying

The Fe-based Ti+Ni3Al+Al2O3 powder mixture is mechanically alloyed in a Spex ball mill. Composites with Fe-based Ti+Ni3Al+Al2O3 addition were produced at 1000 degrees C sintering temperature for 1 h sintering time. The metallurgical properties of these composites were examined by scanning electron microscopy (SEM), optical microscopy (OM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and microhardness analyses. The final products produced by mechanical alloying were nanocrystalline nickel-rich solid solution and the size of average crystallite was in the range of a few nanometres. Titanium content in the reinforcement increased microhardness values of composite. The produced composites included Fe3Al, TiAl, NiAl, Al3Ni2, Al2O3 and Fe3O phases.KAYALAR copper group; KAYALAR copper Industry and Trade Incorporated CompanyThis work was financially supported by the KAYALAR copper group. The authors are grateful to KAYALAR copper Industry and Trade Incorporated Company for their financial assistance in conducting the experiments

Normlu uzaylarda bazı lineer operatörlerin spektrumu

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Bu çalışma dokuz bölümden oluşmaktadır. İlk bölümde spektrum ile ilgili önceki çalışmalar hakkında kısa bir özet verilip ikinci bölümde konuyla ilgili bazı temel tanım ve teoremler verilmiştir. Üçüncü bölümde normlu uzaylarda lineer operatörlerin spektrumu ve ince spektrumu ile ilgili tanım ve teoremler verilip ayrıca spektrumun alt bölümleri hakkında bazı tanımlar verilmiştir. Dördüncü bölümde Cesaro operatörünün dizi uzayı üzerindeki spektrumu verilmiştir. Beşinci bölümde Rhaly operatörünün bazı dizi uzayları üzerindeki spektrumu incelenmiştir. Altıncı bölümde Fibonacci sayıları kullanılarak E. E. Kara ve M. Başarır [29], elde edilen Fibonacci matrisinin ve dizi uzayları üzerindeki spektrumunu inceledik. Yedinci bölümde; Üst üçgensel ikili bant matrislerinin ince spektrumu incelenmiştir. Sekizinci bölümde; matrisinin dizi uzayı üzerindeki spektrumu incelenmiştir. Son olarak dokuzuncu bölümde; matrisinin dizi uzayı üzerindeki spektrumunu inceledik. Bu çalışmada altıncı ve dokuzuncu bölümde yapılan çalışmalar yaptığımız orijinal çalışmalarımızdır.This study consist of nine sections. After a short summary is given about the spectrum literature in the first section, some definitions and theorems are given about the subject in the second section. In the third section, some definitions and theorems are given about the spectrum and fine spectrum. In addition this, some definitions are given about the subdivisions of spectrum. In the fourth section,the spectrumof the Cesaro operator over the sequence space is investigated. In the fifth section, the spectrum of the Rhaly operator is examined over some sequence spaces. In the sixth section, we determined the spectrum of the Fibonacci matrix, which is defined by Kara an Başarır in [29], over the and . In the seventh section, the fine spectrum of the upper triangular double band matrices are examined. In the eighth section, the spectrum of the is examined over the class of convergent series. In the last section we determined the spectrum of the over the class of convergent series. The studies which are given in the sixth and ninth sections is our original work

MICROSTRUCTURE AND WEAR PROPERTIES OF FeCrC, FeW AND FeTi MODIFIED IRON BASED ALLOY COATING DEPOSITED BY PTA PROCESS ON AISI 430 STEEL

The plasma transferred arc (PTA) process was used for developing wear resistance of AISI 430 steel substrate. Appropriate quantities of FeCrC, FeW and FeTi powders were combined to create conditions that synthesized M7C3 particles into reinforced Fe-based composite surface coating. The phase transformations on new created coated surfaces were comprehensively examined by using a combination of scanning electron microscopy (SEM), microanalysis by energy dispersive spectrometry (EDS), X-Ray diffraction (XRD), microhardness and abrasive wear tests. The microstructure studies of the superficial layers of the coating revealed presence of a mixture of the dendritic phase structure of austenite (gamma) and fine eutectic M7C3 carbides. The results show that; the concentrations of the elements (Cr, W, Ti) added as ferroalloys, the size of dendrites formed in the coated surface, the change of hardness of the coated surfaces, the carbide volume rate and thickness of the coating changed by the variation of the processing parameters (ratio of reinforcement particulates and heat input)

Teachers' opinions on the effectiveness of digital technology in the realization of cognitive objectives

Educational technologies are used as an effective tool in achieving educational objectives. In this research, it is aimed to examine teachers' opinions about the effectiveness level of digital technology in acquiring cognitive objectives. The research was conducted as the sequential explanatory mixed research design. “A questionnaire of technology beliefs for cognitive objectives” and semi-structured interview form developed by the researchers were applied. At the end of the research, it was concluded that teachers' views about the effectiveness of digital technologies in achieving cognitive objectives were generally high. Smart boards and Web 2.0 are thought the most effective tool by the teachers. Respectively computer, tablet pc, smartphone and Web 1.0 come next in that list. It has been seen that smart board and Web 2.0 technologies play an effective role in the acquisition of cognitive objectives by enabling the development of different parameters

THE EFFECT OF SPORTS ON PROBLEM-SOLVING AND AGGRESSION LEVELS IN SECONDARY EDUCATION STUDENTS

The study investigates the effect of doing sports on problem-solving and aggression levels in secondary school students. 501 students between the ages of 13-18 who are continuing their education in the city center of Şırnak in the 2018-2019 academic year have voluntarily participated in our research. The demographic information questionnaire, which was developed by the researcher and consisted of 5 questions, was applied to the participants, and then the Problem Solving Skills Inventory and Aggression Scale were applied. There has no effect of gender on aggression levels (p> 0.05). It has been observed that gender affects the thinking approach (p = 0.011). in problem-solving skills. It has been seen that doing sports did not affect aggression (p > 0.05). While it has observed that doing sports affected the thinking approach (p = 0.019) sub-dimension in problem-solving skills, it did not affect other sub-dimensions (p > 0.05). As a result, it has been determined that gender does not affect aggression and problem-solving skills in secondary education students. While it was observed that doing sports did not affect aggression in secondary education students, it was found that the thinking approach in problem-solving skills did not affect the other sub-dimensions. Further development of students' problem-solving skills at the secondary level is recommended. Article visualizations

Identifying the Factors Influencing Mathematics Teachers' Grading Practices Regarding Students' In-Class Performance: A Reliability and Validity Study

This study aims to develop a scale to identify the factors influencing mathematics teachers' grading practices regarding students' in-class performance. The study was carried out with 180 secondary and 140 high school mathematics teachers from the southwestern region of Türkiye. The scale’s construct validity was determined using item analysis, exploratory factor analysis (EFA), and confirmatory factor analysis (CFA). The EFA results showed that the scale consisted of a 5-point Likert-type scale with 36 items under eight factors (mathematical knowledge and skills, social behaviors, affective skills, effort, homework performance, follow-up test results, academic exam results, and external benchmarks). The scale explained 70.02% of the total variance, with factor loadings ranging from 0.50 to 0.92. The item-total correlations ranged from 0.36 to 0.64, and t-test results for the item discrimination index were significant. The Cronbach's alpha coefficient for the overall scale was calculated to be 0.92. The CFA results indicated that the scale model had a good fit (Chi-square/df = 1.39; RMSEA = 0.051; IFI = 0.98; NNFI = 0.97; CFI= 0.98; and SRMR = 0.062). Based on the findings, the scale is a valid and reliable instrument that may be used in determining the factors influencing mathematics teachers’ grading practices