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Öğe An analysis of the spatio-spectral acoustic filtering effect of sonic crystals(Elsevier Science Bv, 2016) Alagoz, SerkanThis study numerically investigates the spatio-spectral sound transmission properties of a sonic crystal flat lens and presents a discussion on the effects of negative refraction on the spatio-spectral selectivity of sonic crystals. For this propose, pulse response analyses are carried out to demonstrate the spatio-spectral acoustic transmission features of a triangular lattice two-dimensional sonic crystal flat lens at the bottom edge of the second frequency band. The spectral analysis indicates the existence of a spatial filtering effect resulting from the wave focalization of the negative refracted wave beams emitted from a point source. We theoretically demonstrate that this effect can be utilized in the implementation of highly frequency-selective spatial sound filters by using sonic crystal flat lenses from point type acoustic sources. (C) 2016 The Physical Society of the Republic of China (Taiwan). Published by Elsevier B.V. All rights reserved.Öğe A closed-loop energy price controlling method for real-time energy balancing in a smart grid energy market(Pergamon-Elsevier Science Ltd, 2013) Alagoz, B. Baykant; Kaygusuz, Asim; Akcin, Murat; Alagoz, SerkanFuture smart grids will require a flexible, observable, and controllable network for reliable and efficient energy delivery under uncertain generation and demand conditions. One of the mechanisms for efficient and reliable energy generation is dynamic demand-responsive generation management based on energy price adjustments that creates a balance in energy markets. This study presents a closed-loop PID (proportional-integral-derivative) controller-based price control method for autonomous and real-time balancing of energy demand and generation in smart grid electricity markets. The PID control system can regulate energy prices online to respond dynamically and instantaneously to the varying energy demands of grid consumers. Independent energy suppliers in the smart grid decide whether to sell their energy to the grid according to the energy prices declared by the closed-loop PID controller system. Energy market simulations demonstrate that PID-controlled energy price regulation can effectively maintain an energy balance for hourly demand fluctuations of consumers. (C) 2013 Elsevier Ltd. All rights reserved.Öğe A distance-based dynamical transition analysis of time series signals and application to biological systems(Springer, 2012) Alagoz, Serkan; Alagoz, Baris BaykantThis study demonstrates an application of distance-based numerical measures to the phase space of time series signals, in order to obtain a temporal analysis of complex dynamical systems. This method is capable of detecting alterations appearing in the characters of the deterministic dynamical systems and provides a simple tool for the real-time analysis of time series data obtained from a complex dynamical system even with black box functionality. The study presents a possible application of the method in the dynamical transition analysis of real EEG records from epilepsy patients.Öğe Energy Consumption Analysis of Motorized Transportation in Cities by Considering Average Mobile Mass(Ieee, 2016) Alagoz, Basis Baykant; Alagoz, Serkan; Baran, BurhanOngoing migration trend to urban areas populates cities and leads to urbanization problems. A major problem of crowded cities is human mobility. Growing urban population and increase of personal automobiles in traffic lead to energy inefficiency in daily transportation activities and result in emission of more heat and pollutant in urban areas. Energy inefficiency in motorized transportation has negative effects on welfare of citizen, public health, air quality and economy of cities. More carbon emission and related global climate changes are global effects of energy inefficiency in transportation. This study presents an analysis of transportation energy consumption based on average mass mobility. Weighting average function is used to statistically represent transportation mode and social gender patterns of cities. Analysis examples are illustrated and solutions for improvement of energy efficiency are discussed in the aspect of human mobility in urban areas. The study can be useful for evaluation of transportation efficiency.Öğe Experimental observation of far-field and near-field focusing in a sonic crystal flat lens in air(Iop Publishing Ltd, 2011) Alagoz, SerkanThis experimental study demonstrates intensity maps of far-field focusing using a two-dimensional triangular lattice sonic crystal and intensity maps of near-field focusing using a two-dimensional square lattice sonic crystal for various scatter materials. Besides, the paper presents an experimental method to estimate the effective refraction index of far-field flat lenses. The author introduces the experimental setup developed for the research and discusses the results obtained.Öğe Frequency-controlled wave focusing by a sonic crystal lens(Elsevier Sci Ltd, 2009) Alagoz, Serkan; Kaya, Olgun Adem; Alagoz, Baris BaykantIn this study, the frequency dependence of the focalization point was investigated for a sonic crystal lens with a triangular lattice configuration. Theoretical and experimental study results showed that focalization point location of the sonic crystal lens with a triangular lattice configuration depended on the frequency of the wave source in the second frequency band. This property of the sonic crystal lens enables shifting of the focalization point location by means of the frequency of a single acoustic source, and it can find application in technologies based on acoustic wave focusing. (C) 2009 Elsevier Ltd. All rights reserved.Öğe Frequency-controlled wave focusing by a sonic crystal lens (vol 70, pg 1400, 2009)(Elsevier Sci Ltd, 2010) Alagoz, Serkan; Alagoz, Baris Baykant[Abstract Not Available]Öğe An Investigation on Acoustic Wave Focalization by a Square Lattice Flat Lens(Polska Akad Nauk, Polish Acad Sciences, Inst Fundamental Tech Res Pas, 2012) Alagoz, SerkanA sonic crystal consists of a finite-size periodic array of scatters embedded in a background material. One of the fascinating properties of sonic crystals is the focusing phenomenon. In this study, the near field focusing effect of a solid-air 2D sonic crystal lens with a square lattice configuration is investigated in the second frequency band. The band structure and equifrequency contour of the crystal are analyzed to reveal the dispersion of an acoustic wave on the crystal structure. The frequency dependence of the acoustic wave focalization by the sonic crystal flat lens is demonstrated via Finite Difference Time Domain simulation results and experimental measurements.Öğe A Maximum Beam Intersection Method for the Focusing Property Analysis of Flat Lenses(Elsevier, 2012) Alagoz, SerkanThis study presents a statistical method for the focusing point analysis of flat lenses. The proposed method, referred to as the Maximum Beam Intersection method (MBI), analyzes the beam intersection density distribution on the focal axis of a flat lens by means of ray trace analysis. The MBI method not only provides an estimation of the focusing point location but also allows an assessment of the quality of the focusing points. The analysis demonstrates that the ideal imaging effect, obtained in the case of n = -1, has the highest beam intersection density. Results of the MBI method are in agreement with the results of the conventional analytical calculation and the flat lens simulation results.Öğe A note on applications of time-domain solution of Cole permittivity models(Elsevier Gmbh, 2017) Alagoz, Bads Baykant; Alisoy, Gulizar; Alagoz, Serkan; Alisoy, HafizThe complex dielectric permittivity is an important parameter for characterization of electrical properties of dielectric materials. Experimental studies demonstrated that Cole models of dielectric permittivity can provide a better fitting to the experimental data because of allowing for fractional-order frequency dependence. This study aims to investigate physical interpretation of time domain solutions of Cole permittivity models. For this purpose, impulse responses of Cole-Cole model and Davidson-Cole model are expressed in Mittag-Leffler function form by using inverse Laplace transform. The impulse responses of these models are decomposed into impulsive and dispersive components, and the relations of these components with relaxation mechanism of dielectric materials are discussed. By considering impulse response solution of Cole-Cole models, a fractional order dynamic capacitance model is introduced for time domain equivalent circuit modeling of dielectric materials. Moreover, transient properties of electromagnetic wave penetration to dielectric materials are analyzed according to impulse response solution of Cole-Cole model. To illustrate applications of proposed time domain permittivity solutions, the Cole-Cole model of ethyl-acetate liquids was also studied and results are presented. (C) 2017 Elsevier GmbH. All rights reserved.Öğe Opportunities for Energy Efficiency in Smart Cities(Ieee, 2016) Akcin, Murat; Kaygusuz, Asim; Karabiber, Abdulkerim; Alagoz, Serkan; Alagoz, Baris Baykant; Keles, CemalRapid migration from rural to urban areas leads to the emergence of urbanization and sustainability problems. Management and monitoring of resources and infrastructures are getting more important today in crowded cities. Energy consumption is increasing with the growing population and intensified in highly populated parts of cities. This increased energy consumption results in high energy demand as well as the production of more pollutants and heat in these city parts. The management of pollution and heat problems leads to an additional energy demand. Therefore, energy efficiency is becoming central challenge for urban life similar to energy efficient structuring of living organisms. Practically, all activities arranging city life require energy. For instance, job activities, transportation, security, climate, catering, entertainment, commerce etc. In this study, we review active and passive approaches, which can be utilized for improvement of energy efficiency and thus sustainability of urbanization in today's cities. We give a discussion to present a vision for future smart cities in term of improvement of energy utilization and efficiency, and relieve of environmental issues. These approaches can be helpful for future cities for relieving issues originating from population increase.Öğe Removal of spoiling materials from solar panel surfaces by applying surface acoustic waves(Elsevier Sci Ltd, 2020) Alagoz, Serkan; Apak, YasinSurface acoustic wave (SAW) technologies have been widely utilized for sensitive surface cleaning and particle steering applications in micro-electro-mechanical system (MEMS). This study investigates application of SAWs for cleaning of solar PV panel surfaces. Spoiling of photovoltaic (PV) solar panel surfaces is one of major problems that can reduce energy efficiency of PV solar energy systems in outdoor conditions. Rough mechanical cleaning methods can easily damage surface of panels and hence they can reduce efficient working life-span of panels. Therefore, sensitive and electronically controllable self-cleaning techniques are needed to keep PV panel surface cleaner. This study presents a theoretical analysis for detachment phenomenon of dust particles in interaction with SAWs. These analysis considers adhesion forces and effects of gravity in cleaning process and results reveal underlying mechanisms involving in particle detachment process. We derive sufficient conditions that are required for removal of a dust particle from inclined panel surfaces in case of SAW interactions. Experimental studies are conducted with spoiled PV solar panels, and cleaning effects of SAWs on solar panel surface are demonstrated. (C) 2020 Elsevier Ltd. All rights reserved.Öğe Sonic crystal acoustic switch device(Acoustical Soc Amer Amer Inst Physics, 2013) Alagoz, Serkan; Alagoz, Baris BaykantThis study reports a wave-controlled sonic crystal switch device that exhibits a destructive interference-based wave to wave reverse switching effect. By applying control waves, this acoustic device, composed of a two-dimensional square lattice sonic crystal block, reduces acoustic wave transmission from input to output. The finite difference time domain simulation and experimental results confirm the wave-to-wave reverse switching effect at the peak frequencies of the second band. The proposed sonic crystal switch prototype provides a contrast rate of 86% at 11.3 kHz frequency. This wave-to-wave switching effect is useful for controlling wave propagation for smart structure applications. (C) 2013 Acoustical Society of AmericaÖğe A sonic crystal diode implementation with a triangular scatterer matrix(Elsevier Sci Ltd, 2014) Alagoz, SerkanThis paper investigates a nonreciprocal sound transmission effect provided by a triangular lattice two-dimensional sonic crystal made of rods in a triangular cross-section. This sonic crystal (SC) device works as a frequency selective acoustic diode operating at a frequency of 8950 Hz. The scatterer matrix of the sonic crystal diode prototype was composed of triangular shaped wood rods that break the symmetry of the spatial inversion and provide nonreciprocal wave transmission with a contrast rate of 89% in experiments. This acoustic diode device can provide a high contrast, narrow band, one-way sound transmission for acoustic wave control applications. (c) 2013 Elsevier Ltd. All rights reserved.Öğe A space charge motion simulation with FDTD method and application in negative corona electrostatic field analysis(Elsevier Science Inc, 2012) Alagoz, Baris Baykant; Alisoy, Hafiz Z.; Alagoz, Serkan; Hansu, FevziIn this paper, a finite difference time domain based simulation method is presented for the spatio-temporal analysis of space charge motion and the proposed method is applied to negative corona electrostatic field analysis. Drifting and diffusion motion equations of space charges are numerically solved and used in the simulation of corona discharges considering effects of impact ionization, electron attachment, ion-ion recombination and ion-electron recombination. The results obtained from the simulation are discussed. (C) 2012 Elsevier Inc. All rights reserved.
