Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Conference Object Citation - Scopus: 1Modeling and Simulation of Advanced Nuclear Reactors(IEEE Computer Society help@computer.org, 2013-11) Ablay, GünyazAdvanced nuclear power plants are currently being proposed with a number of various designs. However, there is a lack of modeling and control strategies to deal with load following operations. This research investigates a possible modeling approach for advanced nuclear power plants in order to provide an assessment way to the concept designs. The modeling approach covers linear and nonlinear reactor modeling and linear modeling of heat exchanger-turbine- generator systems. Numerical results are presented on an example molten-salt type nuclear power plant system to demonstrate the validity and effectiveness of the modeling approach. © 2013 IEEE. © 2014 Elsevier B.V., All rights reserved.Conference Object Citation - Scopus: 2Design of Wide-Band Tunable Optical Filters With Cascaded Microring Resonators and Shaped-Finger Comb-Drive Actuators(Institute of Electrical and Electronics Engineers Inc., 2016-05) Hah, DooyoungUtilizing the Vernier effect, series coupling of multiple microring resonators with different sizes is used to design a wide-band (free spectral range: 36 nm) tunable filter. For index modulators that shift the filter spectrum by changing effective indices through evanescent coupling, silicon waveguides are considered, which make the fabrication simpler. Effects of the index modulator width to the filter characteristics are studied. A narrower modulator (width: 50 nm) does not incur much loss to the resonator, but requires hopping among several bands since its tuning effect is moderate. On the other hand, a wider modulator (width: 100 nm) can cover the full free spectral range without band hopping, but induces severe loss when it is close to the resonator. The shaped-finger comb-drive actuator design method is applied to obtain linear drop channel control. © 2017 Elsevier B.V., All rights reserved.Conference Object Citation - Scopus: 3Design of Mechanically Tunable Optical Filters With Microring Resonators(Institute of Electrical and Electronics Engineers Inc., 2015-04) Hah, Dooyoung; Bordelon, JohnDesign strategies for the mechanically tunable optical filters with microring resonators and comb-drive actuators are discussed. Electromechanical simulation results are combined with the electromagnetic analysis of the device. A method to design comb-drive actuators to achieve linear resonant wavelength-voltage characteristics is presented. © 2015 Elsevier B.V., All rights reserved.Conference Object Citation - WoS: 3Citation - Scopus: 5Design Considerations for Campus Micro-Grid: MCAST Case Study(Institute of Electrical and Electronics Engineers Inc., 2018-06) Azzopardi, Brian; Azzopardi, Stefan; Mikalauskienė, Renata; Salem, Al Agtash; Hadjidemetriou, Lenos; Tzovaras, Dimitrios K.; Borg, Nicholas Paul; Camilleri, TimThis paper aims to propose design considerations to transform the Malta College of Arts, Science and Technology (MCAST) current and future planned electrical network system into an efficient micro-grid. MCAST is a young higher education and research institution with its campus developing to a state-ofthe-art campus with a vision to establish a living laboratory for training and research. During this study, consumption of electrical loads and photovoltaic (PV) generation have been monitored in real-time to define the micro-grid concept. These measurements provide the values to integrate a combined 63kWp PV system together with intelligent loads such as heating, ventilation and airconditioning systems, and lighting, highlighting the integration capabilities. In addition, the future enlargement of the MCAST micro-grid is considered and recommendations are given on the infrastructure to complete an integral campus wide transformation. Eventually the 3DMgrid would be a blueprint for future micro-grids for training and research purposes. © 2019 Elsevier B.V., All rights reserved.Conference Object Citation - WoS: 3Citation - Scopus: 4Analytical Design of Linear Variable Capacitors With Shaped-Finger Comb-Drive Actuators(Institute of Electrical and Electronics Engineers Inc., 2018-05) Hah, DooyoungVariable capacitors have a broad usage in radio frequency (RF) circuits. Microelectromechanical systems (MEMS) technology can provide variable capacitors with high quality factor and wide tuning range characteristics. One of the design goals for MEMS varactors has been linear capacitance- voltage (C-V) characteristics. To design a linear C-V varactor, a shaped-finger comb-drive actuator is proposed in this paper. The shaped-finger design method, originally developed to obtain linear wavelength-voltage relationships in a tunable optical filter, is modified in this work for a linear C-V varactor, which involves development of a new governing equation. Moreover, conformal mapping is employed in calculation of capacitances, making the whole design process almost all-analytical with the minimum usage of numerical analysis methods. Variable capacitors with the shaped-finger design show linearity factor (LF) - defined as the maximum deviation from the perfect linear relationship - as low as 0.4%, tremendously improved from that of the conventional constant-finger-gap devices (LF: 49.9%). The characteristics of the designed variable capacitor are further investigated through 3-D numerical analysis, and show LF better than 11.5% for the finger thickness in the range between 1 and 10 micrometers. Versatility of the design method is further demonstrated by design of a varactor with linear resonant frequency-voltage (f-V) characteristics for voltage-controlled oscillator (VCO) applications. The developed analytical design method with shaped fingers can find a wide range of applications where comb-drive actuators are used. © 2018 Elsevier B.V., All rights reserved.Article Citation - Scopus: 10Kaya Tutma Hendek Performansının 3-Boyutlu Kaya Düşme Analizleriyle Değerlendirilmesi: Akköy (Ürgüp) Örneği(TMMOB - Jeoloji Muhendisleri Odasi jmo@jmo.org.tr, 2019-12-15) Akin, Mutluhan; Dinçer, İsmail; Orhan, Ahmet H.; Ok, Ali Özgün; Akin, Muge K.; Topal, TamerRockfall ditches or areas can be constructed in order to protect against rockfalls in settlements that are in danger of rockfalls when the population density is not high. Nevertheless, in the design of such protection structures, essential site-specific engineering studies and analyzes are often not carried out appropriately. Therefore, rockfallditches are occasionally not capable of preventing rockfalls. Within the scope of this study, the performance of a 2 m-deep and 1 km-long rockfall ditch excavated at the upper elevation of touristic Akköy (Ürgüp) settlement in 2012 in order to prevent the entrance of falling rocks to the residential area was evaluated on the basis of 3-dimensional rockfall analyses. According to the rockfall risk classification, the settlement is under moderate rockfall risk. The digital surface model used in 3-dimensional rockfall analyses was generated by point cloud data obtained from photogrammetric images taken by unmanned aerial vehicle. During field observations, it was determined that the dimension of the previously fallen ignimbrite blocks could reach up to 2 m. On the other hand, the high persistency of discontinuities in the source zone indicates that the dimensions of the potential rockfall blocks may be large. As a result of the 3-dimensional rockfall analyses carried out in RocPro3D software, it was defined that the falling blocks are generally caught by the ditch excavated between the source zone and the settlement, but in some sections of the ditch those blocks may continue to roll over the rockfall ditch. Eventually, Akköy settlement is still partially under the danger of rockfalls. If the rockfall ditch is not periodically cleaned in the course of time, the extent of danger will enlarge with the decrease in the capacity of the trench. © 2020 Elsevier B.V., All rights reserved.