Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Influence of Microstructure and Crystallographic Texture on Hydrogen Diffusion in If-Steel(Technical Faculty, Bor-serbia, 2023) Baskaya, U.; Gündüz, Orhan; Davut, Kemal; Kilic, Y.; Gunduz, O.; 03.09. Department of Materials Science and Engineering; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe relation between microstructure, crystallographic texture, and hydrogen diffusion was studied on a IF-steel. The steel samples were deep drawn to a strain level of 10%, 20%, 30% and 40% and then the hydrogen diffusion coefficients were determined using the Helios II system. Light optical microscope (LOM), scanning electron microscope (SEM) and electron backscatter diffraction (EBSD) were used for microstructural characterization and crystallographic texture studies. The dependence of microstructural parameters was evaluated by Pearson correlation coefficient (PCC) values. These evaluations showed that local misorientations, crystallographic texture, and dislocation densityare interdependent. The PCC values show that grain size and dislocation density are the independent microstructure related parameters. These parameters were used to build a model to predict the hydrogen diffusion coefficient by multiple linear regression analysis. A sensitivity analysis was also performed with this model to understand to which parameter the hydrogen diffusion is most sensitive. The results of this analysis show that hydrogen diffusion is more sensitive to dislocation density, suggesting that dislocations are more effective trapping sites for hydrogen atoms. On the other hand, grain boundaries are less effective trapping sites since they also provide an additional diffusion mechanism.Article Citation - WoS: 61Citation - Scopus: 68Energy and Environmental Performance Based Decision Support Process for Early Design Stages of Residential Buildings Under Climate Change(Elsevier, 2019) Gerçek, Mümine; Durmuş Arsan, Zeynep; Arsan, Zeynep Durmuş; 02.02. Department of Architecture; 02. Faculty of Architecture; 01. Izmir Institute of TechnologyBuilding design decisions have high impacts on energy and environmental performance of buildings. Especially, conscious decisions in earlier design stages are more significant due to lifespan impact of buildings. Deficiencies in systematic approach for design decision support to increase energy and environmental performance of buildings are projected as the major problems of this study. Decisions for performance-based design should be made in terms of the most effective design parameters peculiar for each project. This study exemplifies the act of design decision support in early design stage of a residential building in Turkey. The relation between design parameters and annual energy consumption for heating, cooling and annual operational CO2 emissions is examined by global sensitivity analyses for the present, 2020s, 2050s and 2080s weather conditions. Design process requires the assessment of the uncertainties in building performance caused both by design parameters and climate change. The results indicate that the decisions about solar heat gain coefficients (SHGC), and heat transfer coefficients (U) of transparent surfaces on building envelope have the highest impacts on energy and environmental performance of residential buildings in hot-humid climatic conditions.Article Citation - WoS: 54Citation - Scopus: 59An Approach for Developing Sensitive Design Parameter Guidelines To Reduce the Energy Requirements of Low-Rise Apartment Buildings(Elsevier Ltd., 2012) Yıldız, Yusuf; Korkmaz, Koray; Durmuş Arsan, Zeynep; Durmuş Arsan, Zeynep; Korkmaz, Koray; 02.02. Department of Architecture; 02. Faculty of Architecture; 01. Izmir Institute of TechnologyHigh levels of energy consumption in residential buildings and global warming are important issues. Thus the energy performance of buildings should be improved in the early stages of design. This article describes an approach for developing guidelines on sensitive and robust design parameters for the present, the 2020s, the 2050s and the 2080s. Such guidelines can help architects to design low-rise apartment buildings that require less energy for various purposes, such as heating or cooling. The article consists of a general literature review, interviews with architects, the generation of case-specific information and a mock-up presentation and a meeting with professionals. An example guideline that aims to reduce annual cooling energy loads under global warming in low-rise apartment buildings located in hot-humid climates is presented to demonstrate how the proposed approach can be applied. For this guideline, case-specific information was generated, and a global sensitivity analysis based on Monte Carlo Analysis and the Latin Hypercube Sampling technique was performed. The results show that the suggested approach is feasible and could be used to provide helpful information to architects during the design of low-rise apartment buildings with high energy performance. The most sensitive design parameters that affect annual cooling energy loads in low-rise apartment buildings were natural ventilation, window area, and the solar heat-gain coefficient (SHGC) of the glazing. The results are relevant for the present, the 2020s, the 2050s and the 2080s.Article Citation - WoS: 4Citation - Scopus: 9Identifying Critical Architectural Components With Spectral Analysis of Fault Trees(Elsevier Ltd., 2016) Ayav, Tolga; Ayav, Tolga; 03.04. Department of Computer Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyWe increasingly rely on software-intensive embedded systems. Increasing size and complexity of these hardware/software systems makes it necessary to evaluate reliability at the system architecture level. One aspect of this evaluation is sensitivity analysis, which aims at identifying critical components of the architecture. These are the components of which unreliability contributes the most to the unreliability of the system. In this paper, we propose a novel approach for sensitivity analysis based on spectral analysis of fault trees. We show that measures obtained with our approach are both consistent and complementary with respect to the recognized metrics in the literature.Article Doe and Ann Models for Powder Mixture Packing(American Ceramic Society, 2007) Akkurt, Sedat; Romagnoli, Marcello; Akkurt, Sedat; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyDesign of experiments (DOE) and artificial neural network (ANN) techniques were used to study packing of fused alumina powders composed of three different sizes of particles. The first is the mixture design technique that produces a polynomial model of the powder-packing system. While, the ANN technique is extensively used to model complex systems in many fields. The methodological approach used is mixture design, which can be used to study the influences of two or more additives. It is a structured and organized method for determining the relationship between the components and the output of that process. The mixture design approach permits optimization of size distribution to obtain a target value of porosity. Sensitivity analysis involves the use of the developed ANN model to predict outputs (porosity) at varying levels of the input factor effects.Article Citation - WoS: 33Citation - Scopus: 38Modeling Two-Dimensional Erosion Process Over Infiltrating Surfaces(American Society of Civil Engineers (ASCE), 2001) Tayfur, Gökmen; Tayfur, Gökmen; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe physics-based modeling of the rainfall-runoff induced erosion process is accomplished. The existing one-dimensional erosion process equations are extended to two dimensions and kinematic wave approximation is used. The model assumes that suspended sediment does not affect flow dynamics. The model considers the effect of flow depth plus loose soil depth on soil detachment. Sensitivity analysis results indicate that the effects of the soil erodibility coefficient (η) and exponent (k1) on sediment discharges are quite pronounced. On steep slopes, the effect of flow depth plus loose soil depth on sediment discharge is insignificant.