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Article Citation - WoS: 7Citation - Scopus: 8Robust and Adaptive Control Design of a Drilling Rig During the Operating Modes(Sage Publications Ltd, 2019) Sadeghi, Amir Nobahar; Arikan, Kutluk Bilge; Ozbek, Mehmet Efe; Baranoglu, BesimOil well drilling towers have different operating modes during a real operation, like drilling, tripping, and reaming. Each mode involves certain external disturbances and uncertainties. In this study, using the nonlinear model for the modes of the operation, robust and/or adaptive control systems are designed based on the models. These control strategies include five types of controllers: cascaded proportional-integral-derivative, active disturbance rejection controller, loop shaping, feedback error learning, and sliding mode controller. The study presents the design process of these controllers and evaluates the performances of the proposed control systems to track the reference signal and reject the uncertain forces including the parametric uncertainties and the external disturbances. This comparison is based on the mathematical performance measures and energy consumption. In addition, three architectures are presented to control the weight on bit during drilling process, and also to maintain a preset constant weight on bit, two control approaches are designed and presented.Article Citation - WoS: 8Citation - Scopus: 7Nodular Cast Iron Ggg40, 60, 70 Mechanical Characterization From Bars and Blocks Obtained From Brazilian Foundry(Mdpi, 2022) Fernandes, Daniel de Oliveira; Mota Anflor, Carla Tatiana; Vaz Goulart, Jhon Nero; Baranoglu, BesimNodular cast iron has been commonly applied in industry and many engineering applications due to its low production cost and the similarity of its mechanical properties to carbon steel. The mechanical properties of nodular cast iron are very dependent on its microstructure and also on the characteristics of the graphite nodules. In this sense, the main objective of this paper was to evaluate and characterize the nodular cast iron grades GGG40, GGG60 and GGG70 in the absence of heat treatment. In addition, specimens were obtained from casted bars and blocks without the Y-block casting process. The microstructure was analyzed by optical microscopy with the support of computational image analysis for determination of the attributes of the graphite nodules and the quantification of each phase present in the microstructure of the nodular cast iron. The results showed that the microstructure has a strong effect on the material's strength, especially the density of graphite nodules in the material. This difference reinforces the idea that cast iron can undergo mechanical changes due to changes in the casting process, confirming the importance of checking the characteristics of the cast batch before engineering applications of the material.Article An Adaptive Element Division Algorithm for Accurate Evaluation of Singular and Near Singular Integrals in 3d(Tubitak Scientific & Technological Research Council Turkey, 2021) Bayindir, Hakan; Baranoglu, Besim; Yazici, AliAn adaptive algorithm for evaluation of singular and near singular integrals in 3D is presented. The algorithm is based on successive adaptive/selective subdivisions of the element until a prescribed error criteria is met. For evaluating the integrals in each subdivision, Gauss quadrature is applied. The method is computationally simple, memory efficient and can be applied for both triangular and quadrilateral elements, including the elements with nonplanar and/or curved surfaces. To assess the method, several examples are discussed. It has shown that the algorithm performs well for singular and near-singular integral examples presented in the paper and evaluates the integrals with very high accuracy.
