Abstract
The interrogation of optic fiber sensors usually relies in complex and costly equipment with low portability due to their size such as Optical Spectrum Analyzers (OSA) or high-resolution spectrometers. Because of this, micro spectrometer devices, such as Micro-Electromechanical Systems (MEMS) with Fabry-Pérot tunable filters, are emerging as simpler and compact alternatives capable of being used to acquire spectral information in a wide wavelength band. In this work it is described the development of an interrogation system capable of infrared spectroscopy using a MEMS Fabry-Pérot Interferometer (MEMS-FPI) with a spectral response in the 1350nm to 1650nm range. Its performance is tested with the interrogation of long period fiber gratings both as a refractive index sensor and as a temperature sensor. Deconvolution techniques such as Wiener filtering are used to reduce the impact of the tunable filter's impulse response in the measured signal. Results are comparable to those obtained using a typical OSA which shows the system's potential as a cheaper and more transportable alternative. © Published under licence by IOP Publishing Ltd.

Abstract
The identification of olive-tree cultivars is a lengthy and expensive process, therefore, the proposed work presents a new strategy for identifying different cultivars of olive trees using their leaf and machine learning algorithms. In this initial case, four autochthonous cultivars of the Tras-os-Montes region in Portugal are identified (Cobrancosa, Madural, Negrinha e Verdeal). With the use of this type of algorithm, it is expected to replace the previous techniques, saving time and resources for farmers. Three different machine learning algorithms (Decision Tree, SVM, Random Forest) were also compared and the results show an overall accuracy rate of the best algorithm (Random Forest) of approximately 93%.

Abstract

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.

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.

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.