İnşaat Mühendisliği Bölümü Yayın Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/395

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Citation - WoS: 6
Citation - Scopus: 10
Environmental Impact Assessment of Coal Power Plants in Operation
(E D P Sciences, 2017) Kucukali, Serhat; Ar, Irfan; Bartan, Ayfer
Coal power plants constitute an important component of the energy mix in many countries. However, coal power plants can cause several environmental risks such as: climate change and biodiversity loss. In this study, a tool has been proposed to calculate the environmental impact of a coal-fired thermal power plant in operation by using multicriteria scoring and fuzzy logic method. We take into account the following environmental parameters in our tool: CO, SO2, NOx, particulate matter, fly ash, bottom ash, the cooling water intake impact on aquatic biota, and the thermal pollution. In the proposed tool, the boundaries of the fuzzy logic membership functions were established taking into account the threshold values of the environmental parameters which were defined in the environmental legislation. Scoring of these environmental parameters were done with the statistical analysis of the environmental monitoring data of the power plant and by using the documented evidences that were obtained during the site visits. The proposed method estimates each environmental impact factor level separately and then aggregates them by calculating the Environmental Impact Score (EIS). The proposed method uses environmental monitoring data and documented evidence instead of using simulation models. The proposed method has been applied to the 4 coal-fired power plants that have been operation in Turkey. The Environmental Impact Score was obtained for each power plant and their environmental performances were compared. It is expected that those environmental impact assessments will contribute to the decision-making process for environmental investments to those plants. The main advantage of the proposed method is its flexibility and ease of use.
Citation - Scopus: 1
An Innovative Description of Elastic Constant Tensor Based Upon Orthonormal Representations
(Newswood Limited, 2012) Dinçkal, Ç.; Dinçkal, Çiğdem; İnşaat Mühendisliği
A new procedure for representation of elastic constant tensor in terms of its orthonormal decomposed parts is presented. Form invariants and orthonormalized basis elements are used to generate this decomposition method. Numerical examples from various engineering materials serve to illustrate and verify the decomposition procedure. The norm concept of elastic constant tensor and norm ratios are used to study the anisotropy of these materials. It is shown that this method allows to investigate the elastic and mechanical properties of an anisotropic material possessing any material symmetry and determine anisotropy degree of that material. For a material given from an unknown symmetry, it is possible to determine its material symmetry type by this method. © 2012 Newswood Limited. All rights reserved.
Lecture Notes in Engineering and Computer Science
(Newswood Limited, 2012) Dinçkal, Çiğdem
A new procedure for representation of elastic constant tensor in terms of its orthonormal decomposed parts is presented. Form invariants and orthonormalized basis elements are used to generate this decomposition method. Numerical examples from various engineering materials serve to illustrate and verify the decomposition procedure. The norm concept of elastic constant tensor and norm ratios are used to study the anisotropy of these materials. It is shown that this method allows to investigate the elastic and mechanical properties of an anisotropic material possessing any material symmetry and determine anisotropy degree of that material. For a material given from an unknown symmetry, it is possible to determine its material symmetry type by this method.
Citation - Scopus: 2
Microwave Imaging of Plain and Reinforced Concrete for Ndt Using Backpropagation Algorithm
(2012) Güneş, O.; Büyüköztürk, O.
The focus of this paper is implementation of backpropagation algorithm as a solution for the inverse source problem for microwave imaging of plain and reinforced concrete targets for nondestructive evaluation (NDE). The data used in imaging was obtained from numerical simulation of microwave scattering by concrete targets using a finite difference-time domain (FD-TD) technique. Electromagnetic (EM) properties of concrete were obtained from previous experimental research. Simulations were performed using a Gaussian pulse wave excitation for dry concrete cylinders with and without a rebar at the center. Images reconstructed using the backpropagation algorithm showed the potential of the method for concrete NDE while drawing attention to its limitations mainly due to the linearizing assumptions in the algorithm's formulation. © RILEM 2013.
Citation - Scopus: 10
Nondestructive Testing of Materials and Structures: Proceedings of Ndtms-2011, Istanbul, Turkey, May 15-18, 2011
(2012) Büyüköztürk, O.; Taşdemir, M.A.; Güneş, O.; Akkaya, Y.
Nonlineer Denklemleri Çözmek için Yeni Öngörme-düzeltme Tipi Yineli Yöntemler
(2017) Dinçkal, Çiğdem
Bu makale, nonlineer denklemleri çözmek için, iki yeni öngörme-düzeltme tipi yineli yöntem önerir. Bu yöntemler, iyi bilinen ikiye bölme yöntemi ve Newton-Raphson yönteminin kombinasyonuna dayalı bir şekilde oluşturulmuştur. Çeşitli nümerik örnekler, bu yöntemlerin ana amaçlarını doğrulamaya ve nümerik sonuçlarını karşılaştırmaya hizmet etmektedir. Nümerik sonuçlar, herhangi nonlineer bir denklemin tam köküne ulaşmak için elde edilecek yineleme sayısı cinsinden bu yeni önerilen yöntemlerin yakınsama hızlarını test etmek için de sunulmuştur. Elde edilen bu nümerik sonuçlar, önerilen yeni yöntemlerin iyi bilinen her iki yöntemlerden biri olan ikiye bölme ve NewtonRaphson'dan ve ayrıca literatürdeki diğer yöntemlerden de daha iyi performans gösterdiğine de, işaret etmektedir.
On the Mechanical and Elastic Properties of Anisotropic Engineering Materials Based Upon Harmonic Representations
(int Assoc Engineers-iaeng, 2013) Dinçkal, Çiğdem; Dinckal, Cigdem; İnşaat Mühendisliği
This paper presents a new aspect of harmonic decomposition method for elastic constant tensor of various anisotropic materials. Some misprints found in literature are corrected. This procedure derived here, is applied to anisotropic engineering materials possessing different elastic symmetries. In order to gain insight about these applications, numerical illustrations are presented for anisotropic engineering materials. A new description of norm in terms of harmonic tensors is introduced instead of well-known form of norm. This case is a significant innovation for specifying the anisotropy degree of any engineering materials to have opinion about the mechanical and elastic properties of these materials.
Citation - WoS: 1
Citation - Scopus: 4
Orthonormal Decomposition of Third Rank Tensors and Applications
(int Assoc Engineers-iaeng, 2013) Dinckal, Cigdem; Dinçkal, Çiğdem; İnşaat Mühendisliği
A new procedure for representation of third rank tensors in terms of its orthonormal irreducible decomposed parts, namely as irreducible decomposition is presented. Orthonormal tensor basis method is developed by using the results of existing theory in the literature. As an example to third rank tensors, piezoelectricity tensor is decomposed by each method and results of this decomposition methods are compared for this tensor in hexagonal symmetry. As a result of comparison process, it is stated that the results for new method and other one are consistent and each decomposed parts have physical meaning. Moreover, the norm concept of piezoelectricity tensor is used to study the piezoelectric effect of some materials. It is also shown that one can determine in which material the piezoelectric effect is stronger by using the norm for different materials with the same symmetries.
Citation - WoS: 4
Citation - Scopus: 7
The Performance of Water Jet Pumps and Their Application in Slurry Transportation
(Turkish Soc thermal Sciences Technology, 2023) Kokpinar, Mehmet Ali; Gogus, Mustafa
This present work is focused firstly on an experimental investigation for the optimum design of water jet pumps to be used in the hydrotransport of solid particles through pipeline systems. Experiments were conducted in a closed test loop using five types of jet pumps with various dimensions of the driving nozzle, suction nozzle, mixing chamber, and diffuser employing water as driving and suction fluid. The efficiency of each water jet pump element was analyzed and interpretations of results related to each water jet pump were made about the parts to be considered in the optimum design of a water jet pump. From the experimental results, the water jet pump having the optimum mixing chamber, suction nozzle, driving nozzle location, and cross-sectional dimensions produced a maximum efficiency of about 33%. In the second part of the study, the solid particle carrying capacity of water jet pumps in a pipeline system was studied under saltation, moving bed, and heterogeneous flow regimes by introducing seven different types of solid particles having various concentrations into the closed test loop. The effect of jet pumps on separating solid particles from flow in a region was investigated. A curved form of a by-pass system called the 'flow division unit' was added to the main pipeline system and through the flow division unit, then most of the solid particles in the flow were forced to flow towards the suction pipe of the jet pump. As a result of this, only water with very small particle concentrations passed through the centrifugal pumps, and in this way, the wear risk of the centrifugal pump was reduced considerably.

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