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Öğe CUT DIAMETER OF CYCLONE SEPARATORS: PART I. MULTIPLE NONLINEAR REGRESSION(Yildiz Technical University, 2020) Demir, S.; Karadeniz, A.; Ulutas, K.Pressure drop and particle collection efficiency are the two operating parameters for assessing the performance of cyclone separators. Although a great number of practical models exists for predicting the cyclone pressure drop in the design phase, models for estimating particle collection efficiency is very limited. In this study, an improved mathematical model for calculating cut diameter in cyclone separators, which is a measure of particle collection efficiency, was developed based on Lapple’s formula. Modified Lapple’s formula represents the cut diameters with R2 = 0.9969 and relative mean square error (RMSE) of 2.533*10-9. Also, a new empirical regression model was proposed (R2 = 0.9619). The average errors of both models were very close to zero. Performance tests indicated that both models can be used confidently to predict cut diameter in cyclone separators. © 2020 Yildiz Technical University.Öğe Dijkstra algorithm interactive training software development for network analysis applications in GIS(2011) Karas, I.R.; Demir, S.Process of route optimization is one of the basic applications of Network Analyses in Geographic Information Systems. In mathematical background of network analysis applications are graph theory and graph algorithms. Primary graph algorithm employed in process of route optimization is Dijkstra's Algorithm. Dijkstra's Algorithm is placed on the top of linear methods which yield exact solutions. Geographic Information Systems analyses such as the shortest route, the shortest duration and route with the least traffic are solved through Dijkstra's Algorithm. In this study, an interactive training software program, developed for educational use in Geographic Information Systems and Graph Theory classes at postgraduate degree, is introduced. This software provides students with the opportunity to use Dijkstra's Algorithm on graphs which they have designed by themselves and teaches details of algorithm, its working principles and structure of data to them, step by step, through interactive messages and graphics. © Sila Science.Öğe Memory Polynomial with Shaped Memory Delay Profile and Modeling the Thermal Memory Effect(Ieee, 2013) Yuzer, A. H.; Bassam, S. A.; Ghannouchi, F. M.; Demir, S.This paper presents a proposal for a new memory polynomial modeling technique with non-uniform delay taps to capture the thermal memory effects in power amplifiers. In the proposed modeling structure, each order of the memory polynomial is assigned a different memory delay. The delay profile is an exponentially shaped function, instead of equal unit delays for all memory polynomial branches. Three different metrics, the memory effect modeling ratio (MEMR) and the normalized mean square error (NMSE) and spectrum error (SE) are used to benchmark the proposed exponentially shaped delay profile memorial polynomial model performance against previously published models, namely the memoryless, the unit delay and sparse delay memory based polynomial models. The model coefficients of four models are extracted for three different excitation signals, which were selected as a 64-QAM signal around 2.14 GHz with 20 kHz, 30 kHz and 40 kHz bandwidths, ensuring that the thermal memory effects dominate the electrical memory effects. It is shown that the proposed model outperforms all the previously published models for all three excitation signals used in the experiment.Öğe Memory polynomial with shaped memory delay profile and modeling the thermal memory effect(Institute of Electrical and Electronics Engineers Inc., 2013) Yuzer, A.H.; Bassam, S.A.; Ghannouchi, F.M.; Demir, S.This paper presents a proposal for a new memory polynomial modeling technique with non-uniform delay taps to capture the thermal memory effects in power amplifiers. In the proposed modeling structure, each order of the memory polynomial is assigned a different memory delay. The delay profile is an exponentially shaped function, instead of equal unit delays for all memory polynomial branches. Three different metrics, the memory effect modeling ratio (MEMR) and the normalized mean square error (NMSE) and spectrum error (SE) are used to benchmark the proposed exponentially shaped delay profile memorial polynomial model performance against previously published models, namely the memoryless, the unit delay and sparse delay memory based polynomial models. The model coefficients of four models are extracted for three different excitation signals, which were selected as a 64-QAM signal around 2.14 GHz with 20 kHz, 30 kHz and 40 kHz bandwidths, ensuring that the thermal memory effects dominate the electrical memory effects. It is shown that the proposed model outperforms all the previously published models for all three excitation signals used in the experiment. © 2013 IEEE.Öğe Optimization of functionally graded solid-network TPMS meta-biomaterials(Elsevier Ltd, 2024) Pehlivan, F.; Öztürk, F.H.; Demir, S.; Temiz, A.The current study enhances the performance of solid-network triply periodic minimal surface (TPMS) cellular materials through using cell size grading along with the Taguchi method. Cell size grading is a novel technique used to control the size of pores and the surface area without changing the relative density. In this context, experimental compression testing was conducted on six distinct geometries of cell size graded TPMS structures (Diamond, Fischer–Koch S, Gyroid, IWP, Primitive, and Schoen–F-RD) manufactured with dental resin using a masked stereolithography (MSLA) printer. The findings indicated that mean total energy absorption was greater for smaller initial cell sizes (4 and 6 mm) compared to larger sizes (12 mm). Consistent patterns were also observed with respect to final cell sizes. Upon examination of the stress-strain relationships between D and I-WP, it is evident that D exhibits a higher initial peak stress point. However, subsequent to a significant decline, it exhibits a tremendous degree of volatility before recovering. Conversely, I-WP demonstrated greater stability throughout the experiments, with a notably greater maximum stress effect. A significant influence was observed from the initial cell size on stress, with larger sizes leading to a reduction in absorbed energy. The acquired results serve as an essential basis for the identification of optimized designs that may be implemented to enhance the structures' durability. © 2024 Elsevier LtdÖğe Use of geographic information systems in iron and steel industry(2012) Karas, I.R.; Demir, S.Geographic Information Systems are information systems in which spatial data and non-spatial data are managed together. These data related to areas of factoring and production are allowed to be stored, processed, examined and analyzed together with the help of Geographic Information Systems, in contradistinction to other information systems. In our day, the use of Geographic Information Systems is becoming widespread in industrial foundations spread over large areas as a result of the fact that it contains extensive spatial data. Administrations such as inter-facility planning, synchronization of work groups, determining the most suitable areas through the use of environmental and spatial analyses based on location, optimization of production and transportation are some examples of this sort of usage. This paper is going to focus on the usability of Geographic Information Systems in ironsteel industry and bring forward proposals about Geographic Information Systems applications that can be implemented in an iron-steel plant. Advantages that will be gained through the use of Geographic Information Systems, time, cost and performance are going to be examined. © Sila Science.
