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Publicações

Publicações por Catarina Silva Monteiro

2018

A Brief Review of New Fiber Microsphere Geometries

Autores
Gomes, AD; Monteiro, CS; Silveira, B; Frazao, O;

Publicação
Fibers

Abstract

2018

Development of a new system for real-time detection of radon using scintillating optical fibers

Autores
Monteiro, CS; Coelho, L; Barbosa, SM; Guimarães, D;

Publicação
Optics InfoBase Conference Papers

Abstract
A remote sensor for radon continuous measurement using polymeric scintillation optical fibers was developed and evaluated. Successful preliminary results showed detection of natural occurring radon from a container with rocks rich in uranium oxides. © OSA 2018 © 2018 The Author(s)

2019

High sensitivity strain sensor based on twin hollow microspheres

Autores
Monteiro, CS; Kobelke, J; Schuster, K; Bierlich, J; Silva, SO; Frazao, O;

Publicação
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS

Abstract
A sensor based on 2 hollow core microspheres is proposed. Each microsphere was produced separately through fusion splicing and then joined. The resultant structure is a Fabry-Perot interferometer with multiple interferences that can be approximated to a 4-wave interferometer. Strain characterization was attained for a maximum of 1350 mu epsilon, achieving a linear response with a sensitivity of 3.39 +/- 0.04 pm/mu epsilon. The fabrication technique, fast and with no chemical hazards, as opposed to other fabrication techniques, makes the proposed sensor a compelling solution for strain measurements in hash environments.

2019

Graphene oxide as a tunable platform for microsphere-based optical fiber sensors

Autores
Monteiro, CS; Raposo, M; Ribeiro, P; Silva, S; Frazao, O;

Publicação
Proceedings of SPIE - The International Society for Optical Engineering

Abstract
Hollow microsphere fiber sensors are Fabry-Perot interferometers (FPI) that can be used for lateral loading, temperature, and refractive index sensing. In this work, graphene oxide (GO) is explored as a tunable platform for enhancing the spectral properties of hollow microsphere fiber sensors. GO offers similar mechanical and optical properties as graphene, with the advantage of a wider range of deposition methods and a lower cost. The influence of multilayer coatings of polyethylenimine (PEI) and GO, achieved with the layer-by-layer technique, on the reflectivity of the outer surface, and hence, on the spectrum of the FPI for maximum of 30 bilayers was studied. The obtained results revealed a change of the microsphere outer surface reflectivity and also of visibility of the reflected spectrum when varying the number of bilayers. A maximum signal amplitude of 3.9 dB was attained for the 13th bilayer, allowing to conclude that PEI/GO multilayer coatings can be used for enhancing desired properties of the three-wave FPI for different sensing applications. © 2019 SPIE.

2019

3D prototyping of a fiber Bragg grating vibration sensor for power transformers

Autores
Monteiro, CS; Viveiros, D; Linhares, C; Tavares, SMO; Mendes, H; Silva, SO; Marques, PVS; Frazao, O;

Publicação
Proceedings of SPIE - The International Society for Optical Engineering

Abstract
In this work, 3D printing is explored as a solution for fast prototyping of optical fiber sensors with applications in power transformers. Two different sensing structures were evaluated using finite element method (FEM) analysis and were fabricated using 3D printing. The printed structures are composed by acrylonitrile butadiene styrene (ABS), a common thermoplastic polymer used in 3D printing. Attaching a fiber Bragg grating (FBG) to each structure, frequency measurements were successfully obtained for values between 20 and 250 Hz. © 2019 SPIE.

2019

FBG two-dimensional vibration sensor for power transformers

Autores
Monteiro, CS; Vaz, A; Viveiros, D; Linhares, C; Tavares, SMO; Mendes, H; Silva, SO; Marques, PVS; Frazao, O;

Publicação
Proceedings of SPIE - The International Society for Optical Engineering

Abstract
Power transformers are at the core of power transmission systems. The occurrence of system failure in power transformers can lead to damage of adjacent equipment and cause service disruptions. Structural and electrical integrity assessment in real time is of utter importance. Conventional techniques, typically electrical sensors or chemical analysis, present major drawbacks for real-Time measurements due to high electromagnetic interference or for being time-consuming. Optical fiber sensors can be used in power transformers, as they are compact and immune to electromagnetic interferences. In this work, an optical fiber sensor composed by 2 fiber Bragg gratings, attached in a cantilever structure was explored. The prototype was developed with a 3D printer using a typical filament (ABS) that enable a fast and low-cost prototyping. The response of the sensor to vibration was tested using two different vibration axes for frequencies between 10 and 500 Hz. Oil compatibility was also studied using thermal aging and electrical tests. The studies shown that ABS is compatible with the power transformer mineral oil, but the high working temperatures may lead to material creeping, resulting in permanent structural deformation. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

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