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Publications

Publications by CAP

2022

WiPTherm: A novel energy harvesting paradigm for CubeSats

Authors
Navarro Medina, F; Aguado Agelet, F; Garcia Luis, U; Ulloa, C; Orgeira Crespo, P; Camanzo Mariño, A; Dragos Darau, V; Maia, MM; Gomez San Juan, A; Furtado, C; Machado, V; Califórnia, A; Bogas, S; Ferreira, C; Silva, J; Sousa, L; Machado, J; Roy, P; Auguste, J; Jamier, R; Leconte, B; Frazão, O; Robalinho, P; Pires, AL; Roacha, M; Comesaña, R; Pereira, AM;

Publication
Proceedings of the International Astronautical Congress, IAC

Abstract
Given the fact that CubeSats are becoming an alternative for accessible, reduced-risk development for space applications within an emergent technological market and that the power demand of these type of nanosatellites is increasing due to the complexity of the defined missions, an alternative solution to traditional energy harvesting systems (i.e., solar panels and batteries) is proposed within the WiPTherm project. Being a high-risk category (FET-Future and Emerging Technologies) project within the H2020 European funding scheme, it aims to provide a Wireless Energy Transfer solution via a photo-thermoelectric plasmonic (HPTP) generator array device that can convert photonic energy to electrical energy via thermal gradient. In order to create it, a long-range, continuous-wave (CW) laser source targets the cells of the HPTP generator, forming, as such, the photo-thermoelectric plasmonic system. Two possible scenarios were taken into account and presented in terms of mission requirements: the laser source charging the satellite from Earth, or a laser system mounted onto a master satellite charging a CubeSat orbiting Mars/Jupiter, within the context of a deep space mission. The development of such Wireless Energy Transfer (WET) system implies an improvement of the current technology in different research fields, among them: nanomaterials, photonics, electronics, and space systems. For the success of the project, all of them shall be developed considering the different interfaces as well as the assembly principles, to be compatible with the support structure: a 3U CubeSat. From the Assembly, Integration and Verification (AIV) plan point of view, a testing philosophy involving different models is presented: an STM of the complete 3U CubeSat for the development of higher-fidelity tests when evaluating both structural and thermal HPTP baseplate capabilities; an Engineering Model, where all the subsystems will be assembled on the CubeSat platform and all its functionalities tested; development models for all spacecraft subsystems that are new developments and are not off the shelf: HPTP, the CubeSat electrical module and the laser generator. As a conclusion, this work presents the concept beyond the technology herein purposed, its applicability, and, from the systems engineering point of view, the challenges faced on the AIV plan. © 2022 International Astronautical Federation, IAF. All rights reserved.

2022

Embedding Multi-Wall Carbon Nanotubes as Conductive Nanofiller onto Bi2Te3 Thermoelectric Matrix

Authors
Almeida, MAS; Magalhães, JM; Maia, MM; Pires, AL; Pereira, AM;

Publication
U.Porto Journal of Engineering

Abstract
Thermoelectric Generators (TEGs) are devices that have the ability to directly convert heat into electrical power, or vice-versa, and are being envisaged as one off-the-grid power source. Furthermore, carbon-based materials have been used as a conducting filler to improve several properties in thermoelectric materials. The present work studied the influence on the thermoelectric performance of Bi2Te3 bulk materials by incorporating different concentrations of Multi-Walled Carbon Nanotubes (MWCNT). In order to control and understand the influence of MWCNT dispersion in the nanocomposite, two different production methods (manual grinding and ultrasonication) were carried out and compared. It was verified that a larger dispersion leads to a better outcome for thermoelectric performance. The achieved Seebeck coefficient was up to-162 µV K-1 with a Power Factor of 0.50 µW K-2 m-1, for the nanocomposite produced with 11.8 %V of MWCNT. This result demonstrates the ability to increase the thermoelectric performance of Bi2Te3 throughout the addition of MWCNT. © 2022, Universidade do Porto - Faculdade de Engenharia. All rights reserved.

2021

Experimental investigation of a strain gauge sensor based on Fiber Bragg Grating for diameter measurement

Authors
Cardoso, VHR; Caldas, P; Giraldi, MTR; Frazao, O; de Carvalho, CJR; Costa, JCWA; Santos, JL;

Publication
OPTICAL FIBER TECHNOLOGY

Abstract
A strain gauge sensor based on Fiber Bragg Grating (FBG) for diameter measurement is proposed and experimentally demonstrated. The sensor is easily fabricated inserting the FBG on the strain gauge-it was fabricated using a 3D printer-and fixing the FBG in two points of this structure. The idea is to vary the diameter of the structure. We developed two experimental setups, the first one is used to evaluate the response of the FBG to strain and the second one to assess the possibility of using the structure developed to monitor the desired parameter. The results demonstrated that the structure can be used as a way to monitor the diameter variation in some applications. The sensor presented a sensitivity of 0.5361 nm/mm and a good linear response of 0.9976 using the Strain Gauge with FBG and fused taper.

2021

Optical Sensors for Industry 4.0

Authors
Santos, JL;

Publication
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS

Abstract
This work addresses the role of optical sensing within the new emerging paradigm Industry 4.0. It starts with some thoughts about complex systems and their inherent need of enlarged sensorial tools. Then, the principles of optical sensing are presented with identification of the two principal types. After summarizing what is meant by Industry 4.0, it is detailed how optical sensing can contribute to the raise up of this new industrial concept, focusing on vision, physical sensing, chemical sensing, and sensor multiplexing. Emphasis is given in fiber optic sensing and, when feasible, in fiber Bragg grating sensing technology. Finally, some final remarks are delivered.

2021

Second-Order Dispersion Sensor Based on Multi-Plasmonic Surface Resonances in D-Shaped Photonic Crystal Fibers

Authors
Cardoso, MP; Silva, AO; Romeiro, AF; Giraldi, MTR; Costa, JCWA; Santos, JL; Baptista, JM; Guerreiro, A;

Publication
PHOTONICS

Abstract
This paper proposes a scheme to determine the optical dispersion properties of a medium using multiple localized surface plasmon resonances (SPR) in a D-shaped photonic crystal fiber (PCF) whose flat surface is covered by three adjacent gold layers of different thicknesses. Using computational simulations, we show how to customize plasmon resonances at different wavelengths, thus allowing for obtaining the second-order dispersion. The central aspect of this sensing configuration is to balance miniaturization with low coupling between the different localized plasmon modes in adjacent metallic nanostructures. The determination of the optical dispersion over a large spectral range provides information on the concentration of different constituents of a medium, which is of paramount importance when monitoring media with time-varying concentrations, such as fluidic media.

2021

Multi-Plasmonic Resonance Based Sensor for the Characterization of Optical Dispersion Using a D-Shaped Photonic Crystal Fiber

Authors
Cardoso, MP; Silva, AO; Romeiro, AF; Giraldi, MTR; Costa, JCWA; Santos, JL; Baptista, JM; Guerreiro, A;

Publication
IEEE INSTRUMENTATION & MEASUREMENT MAGAZINE

Abstract
Surface plasmon-polaritons are electromagnetic modes that can be excited at a conducting-dielec-tric interface [1]. The engineering of surface plasmon resonance (SPR) based devices is a milestone in the development of optical sensors. The ability to construct an all-optical system to confine lightwave power at subwavelength dimensions with higher levels of sensitivity and resolution in a broad spectral range are the central features that have attracted a rapid-growing interest in SPR sensors [2]. Particularly, minute variations in the refractive index of the surrounding medium (also known as analyte) change significantly the characteristics of the electromagnetic fields of a surface plasmon mode. As a consequence, the spectral shifts in the mode phase and also losses variations in the associated confined power can be used to detect analyte properties that are described in terms of the refractive index [3].

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