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@inproceedings{abbiati2020formulation,
  title = {Formulation of Fragility Curves for Petrochemical Plant Components Based on Synthetic Ground Motion Records and Surrogate Modeling},
  author = {Abbiati, Giuseppe and Di Filippo, Rocco and Sayginer, Osman and Bursi, Oreste S and Paolacci, Fabrizio},
  year = {2020},
  journal = {17th World Conference on Earthquake Engineering, 17WCEE},
  pages = {C002526},
  doi = {10.1115/pvp2019-93685}
}

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@inproceedings{chiasera2020glass,
  title = {Glass photonics: advancements and perspectives},
  author = {Chiasera, Alessandro and Szczurek, Anna and Startek, Kamila and Sayginer, Osman and Tran, Lam Thi Ngoc and Bollani, Monica and Varas, Stefano and Carpentiero, Alessandro and Armellini, Cristina and Chiappini, Andrea and others},
  year = {2020},
  journal = {ICTON}
}

Abstract

In order to shed light on the seismic response of complex industrial plants, advanced finite element models should take into account both multicomponents and relevant coupling effects. These models are usually computationally expensive and rely on significant computational resources. Moreover, the relationships between seismic action, system response and relevant damage levels are often characterized by a high level of nonlinearity, which requires a solid background of experimental data. Vulnerability and reliability analyses both depend on the adoption of a significant number of seismic waveforms that are generally not available when seismic risk evaluation is strictly site-specific. In addition, detection of most vulnerable components, i.e., pipe bends and welding points, is an important step to prevent leakage events. In order to handle these issues, a methodology based on a stochastic seismic ground motion model, hybrid simulation and acoustic emission is presented in this paper. The seismic model is able to generate synthetic ground motions coherent with site-specific analysis. In greater detail, the system is composed of a steel slender tank, i.e., the numerical substructure, and a piping network connected through a bolted flange joint, i.e., the physical substructure. Moreover, to monitor the seismic performance of the pipeline and harness the use of sensor technology, acoustic emission sensors are placed through the pipeline. Thus, real-time acoustic emission signals of the system under study are acquired using acoustic emission sensors. Moreover, in addition to seismic events, also a severe monotonic loading is exerted on the physical substructure. As a result, deformation levels of each critical component were investigated; and the processing of acoustic emission signals provided a more in-depth view of the damage of the analysed components.

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@article{sayginer2020c,
  title = {Seismic Vulnerability Analysis of a Coupled Tank-Piping System by Means of Hybrid Simulation and Acoustic Emission},
  author = {Osman Sayginer and Rocco di Filippo and Aurelien Lecoq and Alessandra Marino and Oreste S Bursi},
  year = {2020},
  journal = {Experimental Techniques},
  doi = {10.1007/s40799-020-00396-3},
  issn = {1747-1567},
  url = {https://doi.org/10.1007/s40799-020-00396-3}
}

Abstract

Thin film optical filters are key components in optical, electrical and architectural applications. Thanks to their simple and flexible structures, these filters increase their popularity in numerous areas such as monitoring, sensing, communication etc. An optical filter consists of ordered dielectric material layers in the nano-micrometre thickness. Combination of these different layers can bring many superior properties which cannot be achieved with a single material, for instance, quarter-wave stack optical filters are widely used to block light at particular wavelengths. For this reason, the design of thin film structures plays an important role in research activities as well as product development.
In this study, we propose an automated design framework for UV-AR Optical Filters. The optical response of the filters is modeled and simulated using the Transfer Matrix Method. After that, the simulation model is coupled with the genetic algorithm which is a meta-heuristic optimization approach. The design objectives aim at to lower transmission spectra through the ultraviolet region while distributing equal transmission rates through the visible optical region in order to show realistic colors for architectural purposes. In order to achieve this goal, independently distributed material layers are considered for the initial design. Moreover, fabrication constraints are a defined in collaboration with Sisecam Turkey and limitations are taken into account through the design framework.

This project is being supported by The Scientific And Technological Research Council of Turkey (TUBITAK) 2209-B Industrial Research Funding Program for Undergraduate Students 2019/1

Keywords: Thin Film Optical Filters, Transfer Matrix Method, Genetic Algorithm, UV-AR Optical Filters

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@conference{collab2,
  title = {An Automated Design Framework for UV-AR Optical Filters},
  author = {Z. Arslanturk and A. Sezgin and O. Sayginer},
  year = {2019},
  journal = {Nano-optics, Nanophotonics and Nanoplasmonics},
  url = {https://collab.sayginer.com/ifofo/abstract-presented-in-nanotr-15-conference/}
}

Abstract

Thin-film optical coatings are commonly used elements in optical, electrical and architectural applications. Their ability to manipulate the spectral behavior of the light is especially beneficial in fields such as monitoring, sensing and communication. A thin film optical coating is a material layer made of dielectric or conductive material with nano to micrometer level thickness. Distribution of thin-film coating layers with different thickness and materials enable us to obtain optical systems with unique properties which cannot be achieved with a single material. In this work, we intended to develop a novel design tool which can replace commercial software available in the market. Thus, we propose an automated design framework enabling novel product developments for thin-film optical coatings. The goal of the framework is to build an autonomous design and optimization engine which can tailor the spectral response of an optical system by choosing coating materials, layer thicknesses and the number of layers. To do that, a Transfer Matrix Method is built based on a simulation model of the optical films. Then, the simulation model was coupled with the Genetic Algorithm which mimics the biological evolution. For a design objective, we aimed to lower transmission spectra response through the ultraviolet region while keeping the transmission response at the desired value for architectural purposes. Fabrication limitations were defined in collaboration with Turkiye Sise ve Cam Fabrikalari A.S. – Sisecam Science and Technology Center and they were incorporated in design process.

This project is being supported by The Scientific And Technological Research Council of Turkey (TUBITAK) 2209-B Industrial Research Funding Program for Undergraduate Students 2019/1

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BibTeX

@conference{collab3,
  title = {Automated Design Framework for Thin Film Optical Coatings Using Material and Geometry Optimization},
  author = {Z. Arslanturk and A. Sezgin and O. Sayginer},
  year = {2019},
  journal = {Şişecam International Glass Conference Combined With 34th Şişecam Glass Symposium “Glass In The Sustainable Future: Achieving What Is Possible},
  issn = {1431-7907},
  url = {https://collab.sayginer.com/ifofo/abstract-presented-in-sisecam-34th-glass-symposium/}
}

Abstract

1-D multilayer dielectric films consisting of seven pairs of SiO2 and TiO2 alternating layers are deposited on a SiO2 substrate using the radio frequency sputtering technique. The thicknesses of the film layers are chosen to reflect the visible radiation around 650 nm. An elastic microcavity layer made of Polydimethylsiloxane was sandwiched between two Bragg reflectors. A fabrication process was then developed for elastic microcavity in order to tailor the thickness, establish the surface planarity and to increase reproducibility of the samples. Optical transmittance of the single Bragg reflector and the microcavity were both simulated and measured. A comparison between measurement data and Transfer Matrix Method calculations shows a favourable correlation. Furthermore, in order to assess the suitability of the microcavity as a force sensor, transmittance measurements were carried out as a function of the applied forces. The change in the elastic microcavity thickness due to applied forces resulted in cavity resonance peak shifts proportional to the applied forces.

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@article{sayginer2019b,
  title = {Fabrication, modelling and assessment of hybrid 1-D elastic Fabry Perot microcavity for mechanical sensing applications},
  author = {Osman Sayginer and Alessandro Chiasera and Lidia Zur and Stefano Varas and Lam Thi Ngoc Tran and Cristina Armellini and Maurizio Ferrari and Oreste S Bursi},
  year = {2019},
  journal = {Ceramics International},
  doi = {10.1016/j.ceramint.2019.01.083},
  issn = {0272-8842}
}

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BibTeX

@conference{collab3b,
  title = {İnce Film Optik Filtreler İçin Otomatize Tasarim Sistemi (in Turkish)},
  author = {Z. Arslanturk and A. Sezgin and O. Sayginer},
  year = {2019},
  journal = {21st National Photonics Workshop (Fotonik ’19),},
  url = {https://collab.sayginer.com/ifofo/abstract-poster-presented-in-fotonik-19-workshop-in-turkish/}
}

Abstract

Seismic risk evaluation of coupled systems of industrial plants often needs the implementation of complex finite element models to consider their multicomponent nature. These models typically rely on significant computational resources. Moreover, the relationships between seismic action, system response and relevant damage levels are often characterized by a high level of nonlinearity, thus requiring a solid background of experimental data. Furthermore, fragility analyses depend on the adoption of a significant number of seismic waveforms generally not available when the analysis is site-specific. To propose a methodology able to manage these issues, we present a possible approach for a seismic reliability analysis of a coupled tank-piping system. The novelty of this approach lies in the adoption of artificial accelerograms, FE models and experimental hybrid simulations to evaluate a surrogate meta-model of our system. First, to obtain the necessary input for a stochastic ground motion model able to generate synthetic ground motions, a disaggregation analysis of the seismic hazard is performed. Hereafter, we reduce the space of parameters of the stochastic ground motion model by means of a global sensitivity analysis upon the seismic response of our system. Hence, we generate a large set of synthetic ground motions and select, among them, a few signals for experimental hybrid simulations. In detail, the hybrid simulator is composed by a numerical substructure to predict the sliding response of a steel tank, and a physical substructure made of a realistic piping network. Furthermore, we use these experimental results to calibrate a refined ANSYS FEM. More precisely, we focus on tensile hoop strains in elbow pipes as a leading cause for leakage, monitoring them with strain gauges. Thus, we present the procedure to evaluate a numerical Kriging meta-model of the coupled system based on both experimental and finite element model results. This model will be adopted in a future development to carry out a seismic fragility analysis.

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BibTeX

@proceedings{101115pvp2019-93685,
  title = {Numerical Surrogate Model of a Coupled Tank-Piping System for Seismic Fragility Analysis With Synthetic Ground Motions},
  author = {Rocco di Filippo and Giuseppe Abbiati and Osman Sayginer and Patrick Covi and Oreste S Bursi and Fabrizio Paolacci},
  year = {2019},
  doi = {10.1115/PVP2019-93685}
}

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BibTeX

@article{di2019seismic,
  title = {Seismic fragility analysis of a coupled tank-piping system with surrogate modelling and synthetic ground motions},
  author = {di Filippo, Rocco and Abbiati, Giuseppe and Sayginer, Osman and Bursi, Oreste S},
  year = {2019},
  doi = {10.1115/pvp2019-93685}
}

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@conference{sayginer2018,
  title = {Er3+ 1-D photonic band gap structure for photonic band edge assisted spontaneous emission enhancement},
  author = {Osman Sayginer and Cesare Meroni and Alessandro Chiasera and Francesco Scotognella and Anna Lukowiak and Giorgio Speranza and Stefano Varas and Lidia Zur and Giancarlo C. Righini and Roberta Ramponi and Oreste Bursi and Maurizio Ferrari},
  year = {2018},
  doi = {10.1016/j.optmat.2018.04.034},
  issn = {0925-3467},
  url = {http://d-photon.fbk.eu/home}
}