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Sobre

Sobre

José Manuel Marques Martins de Almeida é licenciado em Física Aplicada  pela Universidade do Porto, Porto, Portugal. Doutorou-se em Física em 1998 na mesma universidade. Desde 2000 é Professor Associado do Departamento de Física, Universidade de Trás os Montes e Alto Douro, Vila Real, Portugal. Obteve o título de agregado em 2006. Atualmente é investigador do Centro de Fotónica Aplicada do INESC TEC, Porto. Os seus atuais interesses de investigação incluem sensores ópticos, espectroscopia e biofísica.

Tópicos
de interesse
Detalhes

Detalhes

  • Nome

    José Almeida
  • Cargo

    Investigador Coordenador
  • Desde

    17 setembro 2012
  • Nacionalidade

    Portugal
  • Contactos

    +351220402301
    jose.almeida@inesctec.pt
004
Publicações

2024

Impact of gaseous interferents on palladium expansion for hydrogen optical sensing: A time stability study

Autores
Almeida, MAS; Almeida, JMMMD; Coelho, LCC;

Publicação
OPTICS AND LASER TECHNOLOGY

Abstract
Continuous monitoring of hydrogen (H2) concentration is critical for safer use, which can be done using optical sensors. Palladium (Pd) is the most commonly used transducer material for this monitoring. This material absorbs H2 leading to an isotropic expansion. This process is reversible but is affected by the interaction with interferents, and the lifetime of Pd thin films is a recurring issue. Fiber Bragg Grating (FBG) sensors are used to follow the strain induced by H2 on Pd thin films. In this work, it is studied the stability of Pd-coated FBGs, protected with a thin Polytetrafluoroethylene (PTFE) layer, 10 years after their deposition to assess their viability to be used as H2 sensors for long periods of time. It was found that Pd coatings that were PTFE-protected after deposition had a longer lifetime than unprotected films, with the same sensitivities that they had immediately after their deposition, namely 23 and 10 pm/vol% for the sensors with 150 and 100 nm of Pd, respectively, and a saturation point around 2 kPa. Furthermore, the Pd expansion was analyzed in the presence of H2, nitrogen (N2), carbon dioxide (CO2), methane (CH4) and water vapor (H2O), finding that H2O is the main interferent. Finally, an exhaustive test for 90 h is also done to analyze the long-term stability of Pd films in dry and humid environments, with only the protected sensor maintaining the long-term response. As a result, this study emphasizes the importance of using protective polymeric layers in Pd films to achieve the five-year lifetime required for a real H2 monitoring application.

2023

Refractometric sensitivity of Bloch surface waves : perturbation theory calculation and experimental validation

Autores
Dias, BS; De Almeida, JMMM; Coelho, LCC;

Publicação
OPTICS LETTERS

Abstract
The sensitivity of one-dimensional Bloch surface wave (BSW) sensors to external refractive index variations using Kretschmann's configuration is calculated analytically by employing first-order perturbation theory for both TE and TM modes. This approach is then validated by com- parison with both transfer matrix method simulations and experimental results for a chosen photonic crystal structure. Experimental sensitivities of (8.4 +/- 0.2)x102 and (8.4 +/- 0.4)x102 nm/RIU were obtained for the TE and TM BSW modes, corresponding to errors of 0.02% and 4%, respectively, when comparing with the perturbation the- ory approach. These results provide interesting insights into photonic crystal design for Bloch surface wave sensing by casting light into the important parameters related with sen- sor performance.(c) 2023 Optica Publishing Group

2023

Compact biosensor system for the quantification of hydrogen peroxide in milk

Autores
Vasconcelos, H; Matias, A; Mendes, J; Araujo, J; Dias, B; Jorge, PAS; Saraiva, C; de Almeida, JMMM; Coelho, LCC;

Publicação
TALANTA

Abstract
Hydrogen peroxide is usually added to products to delay the development of microorganisms mainly in milk, hence increasing its stability over time, however the side effects can become devastating to human health.A technique is presented consisting of detecting hydrogen peroxide as an adulterant in milk through a sensor where pretreatment of the sample is not necessary, using a single use membrane. The detection of hydrogen peroxide in fresh-raw, whole, semi-skimmed and skimmed milk was performed using a luminol chem-iluminescence reaction.For hydrogen peroxide water solutions, a linear response was attained from 1.0 x 10-4 to 9.0 x 10-3 %w/w and an LOD (limit of detection) of 3.0 x 10-5 %w/w was determined. An R-squared value of 0.97 and a relative standard deviation lower than 10%, were achieved.Hydrogen peroxide concentration as low as 1.0 x 10-3 %w/w was measured for fresh-raw, skim and whole milk and for semi-skimmed milk, as low as 2.0 x 10-3 %w/w.The methodology presented, as long as our knowledge, is original, rapid, ecological and inexpensive. In regard of the sensitivity obtained, the methodology has great possibility to be applied in the detection of hydrogen peroxide in several areas. It is envisaged monitoring of food quality, agriculture systems and environment pollution.

2023

Measuring Water Vapor Sorption Hysteresis of Cement Paste through an Optical Fiber Sensor

Autores
da Silva, PM; Coelho, LCC; de Almeida, JMMM;

Publicação
CHEMOSENSORS

Abstract
Water vapor sorption is a powerful tool for the analysis of cement paste, one of the most used substances by mankind. The monitoring of cementitious materials is fundamental for the improvement of infrastructure resilience, which has a deep impact on the economy, the environment, and on society. In this work, a multimode fiber was embedded in cement paste for real-time monitoring of cement paste water vapor sorption. Changes in the reflected light intensity due to the build-up of water in the cement paste's pores were exploited for this purpose. The sample was 7-day moist cured, and the relative humidity was controlled between 8.9% and 97.6%. Reflected light intensity was converted into a specific surface area of cement paste (133 m(2)/g) and thickness of water through the Brunauer-Emmett-Teller (BET) method and into a pore size distribution through the Barret-Joyner-Halenda (BJH) method. The results achieved through reflected light intensity agree with those found in the literature, validating the usage of this setup for the monitoring of water vapor sorption, breaking away from standard gravimetric measurements.

2023

Spectral Analysis Methods for Improved Resolution and Sensitivity: Enhancing SPR and LSPR Optical Fiber Sensing

Autores
Dos Santos, PSS; Mendes, JP; Dias, B; Perez-Juste, J; De Almeida, JMMM; Pastoriza-Santos, I; Coelho, LCC;

Publicação
SENSORS

Abstract
Biochemical-chemical sensing with plasmonic sensors is widely performed by tracking the responses of surface plasmonic resonance peaks to changes in the medium. Interestingly, consistent sensitivity and resolution improvements have been demonstrated for gold nanoparticles by analyzing other spectral features, such as spectral inflection points or peak curvatures. Nevertheless, such studies were only conducted on planar platforms and were restricted to gold nanoparticles. In this work, such methodologies are explored and expanded to plasmonic optical fibers. Thus, we study-experimentally and theoretically-the optical responses of optical fiber-doped gold or silver nanospheres and optical fibers coated with continuous gold or silver thin films. Both experimental and numerical results are analyzed with differentiation methods, using total variation regularization to effectively minimize noise amplification propagation. Consistent resolution improvements of up to 2.2x for both types of plasmonic fibers are found, demonstrating that deploying such analysis with any plasmonic optical fiber sensors can lead to sensing resolution improvements.

Teses
supervisionadas

2022

Development of optical biosensors for monitoring the deterioration of fresh meat and fish

Autor
Helena Catarina Araújo Soares Guedes Vasconcelos

Instituição
UTAD

2022

Sensores ópticos para medição de campos magnéticos baseados em ondas eletromagnéticas de superfície

Autor
João Pedro Miranda Carvalho

Instituição
UP-FCUP

2022

Sensores em fibra ótica para a deteção de contaminantes na água

Autor
José Miguel da Silva Amaral Pereira

Instituição
UP-FCUP

2022

Wireless optical fibre sensors network for the health monitoring of concrete structures

Autor
Pedro Miguel Madeira da Silva

Instituição

2022

Automatic Marker Labelling For MoCap Systems

Autor
José Miguel Martins Gomes

Instituição
UP-FEUP