Publications by authors named "Piotr Sobotka"

4 Publications

  • Page 1 of 1

UV Sensor Based on Fiber Bragg Grating Covered with Graphene Oxide Embedded in Composite Materials.

Sensors (Basel) 2020 Sep 24;20(19). Epub 2020 Sep 24.

Faculty of Physics, Warsaw University of Technology, 00-662 Warszawa, Poland.

Polymer-matrix composites degrade under the influence of UV radiation in the range of the 290-400 nm band. The degradation of polymer-matrix composites exposed to UV radiation is characterized by extensive aging of the epoxy matrix, resulting in deterioration of their mechanical properties. Glass fibers/epoxy resin composites were made by an out-of-autoclave method whereas a fiber optic sensor was placed between different layers of laminates. In our work, we used a fiber Bragg grating sensor covered with graphene oxide and embedded in a polymer matrix composite to monitor UV radiation intensity. Measurements of UV radiation may allow monitoring the aging process of individual components of the polymer composite. In order to estimate the number of microcracks of epoxy resin, microstructure observations were carried out using a scanning electron microscope.
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http://dx.doi.org/10.3390/s20195468DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7584041PMC
September 2020

Hybrid Fiber Optic Sensor Systems in Structural Health Monitoring in Aircraft Structures.

Materials (Basel) 2020 May 13;13(10). Epub 2020 May 13.

Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warszawa, Poland.

'Smart' structural health monitoring of composite materials with optical fiber sensors is becoming more and more important, especially in the aviation industry. This paper presents an overview of hybrid fiber-optic sensing systems based on scattering techniques, fiber Bragg gratings, interferometric techniques, and polarimetric methods in structural health monitoring. The main purpose of this manuscript is to analyze the possibilities of using hybrid sensors based on fiber optics to monitor composite structures, with a particular emphasis on aircraft structures. Since it is difficult to indicate the most comprehensive approach due to different parameters of the described sensors, the review contains a detailed description of available solutions. We hope that this work will allow for a better and faster selection of the right solution for the problem at hand.
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http://dx.doi.org/10.3390/ma13102249DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7288159PMC
May 2020

Chirped fiber Bragg grating written in highly birefringent fiber in simultaneous strain and temperature monitoring.

Appl Opt 2017 Feb;56(6):1625-1630

A new sensor configuration is proposed for simultaneous strain and temperature monitoring in a composite material that is based on a chirped fiber Bragg grating (CFBG) written in a highly birefringent (HB) polarization-maintaining fiber. The sensor is designed in the reflective configuration in which the CFBG acts both as a reflector and a sensing element. Since CFBG and HB fiber induce changes in the state of polarization (SOP), interference between polarization modes in the reflected spectrum is observed and analyzed. We used a simple readout setup to enable fast, linear operation of strain sensing as well simultaneous strain and temperature measurements in the composite.
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http://dx.doi.org/10.1364/AO.56.001625DOI Listing
February 2017

Optical scanner for 3D radiotherapy polymer gel dosimetry.

Acta Phys Pol A 2012 Nov;122(5):969-974

Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland.

Sophisticated techniques employed in radiotherapy for irradiation of tumours require comprehensive dosimetry allowing for precise, high resolution measurements of radiation dose distribution in three dimensions and verification of treatment planning systems. Polymer gel dosimetry has been shown to be a unique technique for three-dimensional high resolution measurements of absorbed radiation dose distributions. If exposed to ionizing radiation, radical polymerisation and crosslinking of monomeric components take place in a 3D polymer gel dosimeter, leading to the formation of large polymeric structures that scatter visible light. This feature allows for optical observation of the effects of the absorbed dose and its distribution. Presently, magnetic resonance imaging is employed the most often for analysis of 3D polymer gel dosimeters. However, much attention is also being given to the development of optical computed tomography since this technique is hoped to serve as a substitute for expensive and not easily available magnetic resonance imaging. The optical scanner presented in this work consists of a laser diode, a scanning system and a signal detector. A 3D polymer gel dosimeter is measured in an immersion liquid in order to reduce deflection of the light from the dosimeter phantom. The very first results were obtained with the newly constructed scanner for PABIG 3D polymer gel dosimeter, which was inhomogeneously irradiated with Ir brachytherapy source. The results have been contrasted with those for magnetic resonance imaging and are presented in this work together with the description of the optical scanner. Currently, optimization of the optical scanner is performed.
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http://dx.doi.org/10.12693/APhysPolA.122.969DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6101184PMC
November 2012
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