The Experts below are selected from a list of 15174 Experts worldwide ranked by ideXlab platform
Ali Kianifar - One of the best experts on this subject based on the ideXlab platform.
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Optimization of the parabolic Mirror Position in a solar cooker using the response surface method (RSM)
Renewable Energy, 2015Co-Authors: Hosein Zamani, Mohammad Moghiman, Ali KianifarAbstract:The main objective of this study is to develop and improve the thermal and radiative performance of solar cookers. A solar cooker has been designed, constructed and experimentally analyzed to achieve this goal. The designed system contains three narrow, adjustable flat Mirrors that are mounted on a parabolic curved substrate in order to concentrate the reflected solar beam onto the absorber plate. The efficiency of this system depends on many variables that were kept fixed with the exception of the parabolic Mirror Position and operation time. The response surface method was used as the basis of the design and analysis of the experiments. The analysis of the results provided the mathematical function of the effective and overall efficiencies based on the experimental variables that can be adopted to optimize the Mirror Positions at any given time. As a result, a new system was developed with adjustable Mirrors that yields 32.07% and 35.5% increase in the effective and overall efficiencies, respectively. The results have been validated by variance analysis and comparing theoretical and experimental efficiency. The experiments were carried out in Mashhad, Iran at latitude 37, longitude 54, and a height of 985 m above sea level.
Pietro Tesi - One of the best experts on this subject based on the ideXlab platform.
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Self-Tuning Mechanism for the Design of Adaptive Secondary Mirror Position Control
IEEE Transactions on Control Systems Technology, 2015Co-Authors: Giorgio Battistelli, Daniele Mari, Armando Riccardi, Pietro TesiAbstract:Deformable Mirrors (DMs) are electromechanical devices used in ground-based telescopes to compensate for the distortions caused by the atmospheric turbulence, the main factor limiting the resolution of astronomical imaging. Adaptive secondary Mirrors (ASMs) represent a new type of DMs; two of them have been recently installed on the 8-m-class large binocular telescope (LBT). ASMs are able to jointly correct rigid and nonrigid wave-front distortions thanks to the use of force actuators distributed on the overall Mirror surface. As an offset, each actuator needs to be piloted by a dedicated controller, whose parameters must be accurately tuned to obtain the desired Mirror shape. At the present time, the calibration of the controller parameters is executed manually. This paper presents a novel automatic controller tuning procedure that does not rely on the modeling of the Mirror dynamics. The experimental validation on a prototype reproducing the three innermost rings of the LBT ASM is reported.
Hosein Zamani - One of the best experts on this subject based on the ideXlab platform.
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Optimization of the parabolic Mirror Position in a solar cooker using the response surface method (RSM)
Renewable Energy, 2015Co-Authors: Hosein Zamani, Mohammad Moghiman, Ali KianifarAbstract:The main objective of this study is to develop and improve the thermal and radiative performance of solar cookers. A solar cooker has been designed, constructed and experimentally analyzed to achieve this goal. The designed system contains three narrow, adjustable flat Mirrors that are mounted on a parabolic curved substrate in order to concentrate the reflected solar beam onto the absorber plate. The efficiency of this system depends on many variables that were kept fixed with the exception of the parabolic Mirror Position and operation time. The response surface method was used as the basis of the design and analysis of the experiments. The analysis of the results provided the mathematical function of the effective and overall efficiencies based on the experimental variables that can be adopted to optimize the Mirror Positions at any given time. As a result, a new system was developed with adjustable Mirrors that yields 32.07% and 35.5% increase in the effective and overall efficiencies, respectively. The results have been validated by variance analysis and comparing theoretical and experimental efficiency. The experiments were carried out in Mashhad, Iran at latitude 37, longitude 54, and a height of 985 m above sea level.
Tokuyuki Honda - One of the best experts on this subject based on the ideXlab platform.
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Pattern dynamics and competition in a photorefractive feedback system
Journal of the Optical Society of America B, 1998Co-Authors: Cornelia Denz, Michael Schwab, Markus Sedlatschek, Theo Tschudi, Tokuyuki HondaAbstract:We investigate the temporal dynamics of transverse optical patterns spontaneously formed in a photorefractive single-feedback system with a virtual feedback Mirror. The linear stability analysis for the system is reviewed and extended to the region of larger propagation lengths. The stationary patterns obtained experimentally are classified as a function of feedback reflectivity and feedback Mirror Position. Inserting masks into the feedback path permits pattern selection and control by Fourier filtering. When an asymmetry that is due to noncollinear pump beams is introduced, the otherwise stationary hexagons show several complex but periodic rotationlike motions. Furthermore, the competition of hexagonal and square patterns can be observed by the appropriate choice of feedback Mirror Position and coupling strength. The origin of this behavior is discussed. The temporal evolution of the patterns is illustrated by a method based on unfolding the angular distribution of the spots in the far field.
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Threshold for spontaneous pattern formation in reflection-grating-dominated photorefractive media with Mirror feedback
Optics letters, 1996Co-Authors: Tokuyuki Honda, Partha P. BanerjeeAbstract:A theoretical analysis is presented of spontaneous pattern formation in a system consisting of a photorefractive medium and a feedback Mirror. A threshold condition for the pattern formation is derived from a new set of coupling equations with the assumption that reflection gratings are dominant. It is shown that the pattern formation can occur with only energy coupling. The direction of the sideband beams is calculated as a function of the Mirror Position, and the result is compared with that of an experiment with a KNbO3 crystal.
Mohammad Moghiman - One of the best experts on this subject based on the ideXlab platform.
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Optimization of the parabolic Mirror Position in a solar cooker using the response surface method (RSM)
Renewable Energy, 2015Co-Authors: Hosein Zamani, Mohammad Moghiman, Ali KianifarAbstract:The main objective of this study is to develop and improve the thermal and radiative performance of solar cookers. A solar cooker has been designed, constructed and experimentally analyzed to achieve this goal. The designed system contains three narrow, adjustable flat Mirrors that are mounted on a parabolic curved substrate in order to concentrate the reflected solar beam onto the absorber plate. The efficiency of this system depends on many variables that were kept fixed with the exception of the parabolic Mirror Position and operation time. The response surface method was used as the basis of the design and analysis of the experiments. The analysis of the results provided the mathematical function of the effective and overall efficiencies based on the experimental variables that can be adopted to optimize the Mirror Positions at any given time. As a result, a new system was developed with adjustable Mirrors that yields 32.07% and 35.5% increase in the effective and overall efficiencies, respectively. The results have been validated by variance analysis and comparing theoretical and experimental efficiency. The experiments were carried out in Mashhad, Iran at latitude 37, longitude 54, and a height of 985 m above sea level.