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Sobre

Sobre

Investigador Auxiliar do CRAS, doutorado em Engenharia Eletrotécnica e de Computadores, no Departamento de Eletrónica Industrial da Universidade do Minho, em Dezembro de 2013. Desenvolvo transdutores de ultrassons piezoelétricos aplicados a comunicações sem fios em ambientes subaquáticos e desenvolvo diferentes sensores de baixo custo e tamanho reduzido. Participo e/ou lidero a execução de um total de 14 Projetos de P&D com financiamento competitivo, dos quais 2 como IP e 4 como Co-PI.

Tópicos
de interesse
Detalhes

Detalhes

  • Nome

    Marcos Martins
  • Cargo

    Investigador Auxiliar
  • Desde

    01 junho 2022
001
Publicações

2025

DBD plasma-treated polyester fabric coated with doped PEDOT:PSS for thermoregulation

Autores
Magalhães, C; Isabel Ribeiro, A; Rodrigues, R; Meireles, Â; Alves, C; Rocha, J; Pedroso de Lima, F; Martins, M; Mitu, B; Satulu, V; Dinescu, G; Padrão, J; Zille, A;

Publicação
Applied Surface Science

Abstract
The manufacturing process of thermoregulation products with polyester (PES) fabric and conductive polymers such as poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) with proper wearability, comfort, and high performance is still a challenge due to low adhesion, environment instability and non-uniform coatings. This study presents a simple and effective method for producing thermoregulatory PES fabrics using the Joule heating effect. Textiles treated with dielectric barrier discharge (DBD) plasma were functionalized with PEDOT:PSS incorporating secondary dopants, such as dimethyl sulfoxide (DMSO) and glycerol (GLY). PEDOT:PSS was used because it does not compromise the mechanical properties of base materials. DBD plasma treatment was applied to PES to improve the substrate's functional groups and consequently increase adhesion and homogeneity of the PEDOT:PSS on the substrate. The polymer were applied to the textiles by dip-pad-dry-cure method ensuring uniform distribution and homogeneous heating of the materials. The samples’ conductivity, impedance, potential and Joule effect, and their morphological, chemical and thermal properties were studied. Control samples without plasma treatment and secondary dopants were also prepared. The results showed that the DBD-treated samples, coated with 5 layers of PEDOT:PSS, doped with DMSO 7 % (w/v), displayed the best conductivity and Joule effect performance reaching 44.3 °C after 1 h. © 2024 The Author(s)

2024

The Influence of Hydroxyapatite Crystals on the Viscoelastic Behavior of Poly(vinyl alcohol) Braid Systems

Autores
Quinaz, T; Freire, TF; Olmos, A; Martins, M; Ferreira, FBN; de Moura, MFSM; Zille, A; Nguyen, Q; Xavier, J; Dourado, N;

Publicação
BIOMIMETICS

Abstract
Composites of poly(vinyl alcohol) (PVA) in the shape of braids, in combination with crystals of hydroxyapatite (HAp), were analyzed to perceive the influence of this bioceramic on both the quasi-static and viscoelastic behavior under tensile loading. Analyses involving energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) allowed us to conclude that the production of a homogeneous layer of HAp on the braiding surface and the calcium/phosphate atomic ratio were comparable to those of natural bone. The maximum degradation temperature established by thermogravimetric analysis (TGA) showed a modest decrease with the addition of HAp. By adding HAp to PVA braids, an increase in the glass transition temperature (Tg) is noticed, as demonstrated by dynamic mechanical analysis (DMA) and differential thermal analysis (DTA). The PVA/HAp composite braids' peaks were validated by Fourier transform infrared (FTIR) spectroscopy to be in good agreement with common PVA and HAp patterns. PVA/HAp braids, a solution often used in the textile industry, showed superior overall mechanical characteristics in monotonic tensile tests. Creep and relaxation testing showed that adding HAp to the eight and six-braided yarn architectures was beneficial. By exhibiting good mechanical performance and most likely increased biological qualities that accompany conventional care for bone applications in the fracture healing field, particularly multifragmentary ones, these arrangements can be applied as a fibrous fixation system.

2024

Design of a sensor to estimate suspended sediment transport in situ using the measurements of water velocity, suspended sediment concentration and depth

Autores
Matos, T; Martins, MS; Henriques, R; Goncalves, LM;

Publicação
JOURNAL OF ENVIRONMENTAL MANAGEMENT

Abstract
The sediment transport plays a major role in every aquatic ecosystem. However, the lack of instruments to monitor this process has been an obstacle to understanding its effects. We present the design of a single sensor built to measure water velocity, suspended sediment concentration and depth in situ, and how to associate the three variables to estimate and analyse sediment transport. During the laboratory calibrations, the developed instrument presented a resolution from 0.001 g/L to 0.1 g/L in the 0-12 g/L range for the measurement of suspended sediment concentration and 0.05 m/s resolution for 0-0.5 m/s range and 0.001 m/s resolution for 0.5-1 m/s range for the measurement of water velocity. The device was deployed for 6 days in an estuarine area with high sediment dynamics to evaluate its performance. During the field experiment, the sensor successfully measured the tidal cycles and consequent change of flow directions, and the suspended sediment concentration in the area. These measurements allowed to estimate water discharge and sediment transport rates during the different phases of tides, and the daily total volume of water and total amount of sediment passing through the estuary.

2024

A Demonstrator for Future Fiber-Optic Active SMART Repeaters

Autores
Cruz, NA; Silva, A; Zabel, F; Ferreira, B; Jesus, SM; Martins, MS; Pereira, E; Matos, T; Viegas, R; Rocha, J; Faria, J;

Publicação
OCEANS 2024 - SINGAPORE

Abstract
The deep-sea environment still presents many challenges for systematic, comprehensive data acquisition. The current generation of SMART cables incorporates low-power sensors in long-range telecommunication cables to improve knowledge of ocean variables, aid in earthquake and tsunami warnings, and enhance coastal protection. The K2D Project seeks to expand SMART cables' capabilities by increasing the diversity of sensors along deep water cables, integrating active devices, and leveraging mobile platforms like deep-water AUVs, thereby improving spatial coverage and advancing ocean monitoring technology. This paper discusses a demonstration of these capabilities, focusing on the description of the main building blocks developed along the project, with results from a sea deployment in September 2023.

2024

Exploring local chlorine generation through seawater electrolysis to Extend optical sensor lifespan in marine environments

Autores
Matos, T; Pinto, VC; Sousa, PJ; Martins, MS; Fernández, E; Goncalves, LM;

Publicação
CHEMICAL ENGINEERING JOURNAL

Abstract
Biofouling in marine optical sensors poses a significant challenge as it can compromise data accuracy and instrument functionality. This study investigates the effectiveness of local chlorine generation by seawater electrolysis in mitigating biological fouling and extending the operational lifespan of optical oceanographic instruments. Eight similar turbidity probes integrated with a local chlorine generation system, along with a turbidity probe constructed from ABS and another from PLA with copper filament, were developed for testing in the marine environment. The chlorine probes were designed into two groups: four utilizing standard FTO glass and four featuring FTO glass coated with platinum nanoparticles. Each set of probes employed different excitation currents for chlorine generation. All probes underwent laboratory calibration using formazine before deployment in a coastal environment for 97 days. The findings demonstrate a correlation with higher electrical power leading to prolonged operation intervals free from biofouling interference. Additionally, probes coated with platinum nanoparticles demonstrate higher performance in comparison to those with standard FTO glass. The copper probe did not effectively shield the optical transducers from microfouling, although it effectively demonstrated its efficacy in protecting the structural housing of the device. Overall, this work offers a compelling in situ demonstration of local chlorine generation as a promising strategy for enhancing the performance and longevity of optical oceanographic instruments in marine environments.

Teses
supervisionadas

2024

Acoustic Communication System for Underwater Environments

Autor
Diogo José Ferreira Cerqueira

Instituição
UM

2023

Estudo do sistema de portas dos fornos Bur-in

Autor
Nuno Costa

Instituição
UM

2023

Acoustic Communication System for Underwater Environments

Autor
Diogo José Ferreira Cerqueira

Instituição
UM

2022

Otimização de um sensor pH para monitorização marinha

Autor
Ana Gabriela Vaz Viana

Instituição
UM

2022

Desenvolvimento de um sensor acústico para medição da corrente marítima

Autor
Rafael CAchetas Pereira

Instituição
UM