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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

002
Publicações

2022

Analysis of the Relative Humidity Response of Hydrophilic Polymers for Optical Fiber Sensing

Autores
Dias, B; Carvalho, J; Mendes, JP; Almeida, JMMM; Coelho, LCC;

Publicação
POLYMERS

Abstract
Relative humidity (RH) monitorization is of extreme importance on scientific and industrial applications, and optical fiber sensors (OFS) may provide adequate solutions. Typically, these kinds of sensors depend on the usage of humidity responsive polymers, thus creating the need for the characterization of the optical and expansion properties of these materials. Four different polymers, namely poly(vinyl alcohol), poly(ethylene glycol), Hydromed™ D4 and microbiology agar were characterized and tested using two types of optical sensors. First, optical fiber Fabry–Perot (FP) tips were made, which allow the dynamical measurement of the polymers’ response to RH variations, in particular of refractive index, film thickness, and critical deliquescence RH. Using both FP tips and Long-Period fiber gratings, the polymers were then tested as RH sensors, allowing a comparison between the different polymers and the different OFS. For the case of the FP sensors, the PEG tips displayed excellent sensitivity above 80%RH, outperforming the other polymers. In the case of LPFGs, the 10% (wt/wt) PVA one displayed excellent sensitivity in a larger working range (60 to 100%RH), showing a valid alternative to lower RH environment sensing.

2022

Study of LSPR Spectral Analysis Techniques on SPR Optical Fiber Sensors

Autores
Dos Santos, PSS; de Almeida, JMMM; Coelho, LCC;

Publicação
U.Porto Journal of Engineering

Abstract
Nanoparticles create localized surface plasmonic resonances (LSPR) with lower surrounding refractive index (SRI) sensitivities than their propagating SPR counterpart, originated in thin films. Historically, LSPR SRI sensitivities enhancements were achieved through spectral analysis methods that focus on unique spectral features. Herein, a study using that methodology was applied on SPR devices resulting in an increased sensitivity to SRI. It was found that by applying the inflection point method on optical fiber SPR sensors resulted in both sensitivity and resolution increments up to 44 and 35 %, respectively, in the SRI range from 1.3333 to 1.4150. Thus, successfully improving sensing capabilities of SPR based optical fiber sensors.

2022

Long-Period Fiber Gratings Coated with Poly(ethylene glycol) as Relative Humidity Sensors

Autores
Dias, B; de Almeida, JMMM; Coelho, LCC;

Publicação
U.Porto Journal of Engineering

Abstract
Relative humidity is an important parameter in controlled environments and is typically monitored using low-cost electrochemical sensors with low resolution and accuracy. This kind of sensors cannot not be implemented in harsh or explosive environments (as in pyrotechnic facilities) due to electrical discharges, or in marine structures where the oxidation of the sensing probe materials changes the sensing response). In these cases, fiber optic sensors can provide solutions due to their intrinsic properties, such as immunity to electromagnetic interference and resistance in harsh environments. This work presents preliminary results regarding the steps of the fabrication of Long-Period Fiber Gratings, the coating processes with a thin layer of poly(ethylene glycol) (PEG) and its sensing performance to relative humidity, displaying a from 60 to 100%sensitivity of 0.6 nm/%RH in the range of 80 to 100%RH.

2022

Simple Optical Fiber Interferometer for Dynamic Measurement of Refractive Index and Thickness of Polymer Films

Autores
Dias, B; Mendes, JPS; de Almeida, JMMM; Coelho, LCC;

Publicação
IEEE SENSORS JOURNAL

Abstract

2022

Optical biosensor for the detection of low concentrations of hydrogen peroxide in milk samples

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

Publicação
OPTICAL SENSING AND DETECTION VII

Abstract
A strategy for the detection of H2O2 as a milk adulterant using a single shot membrane sensor, is presented. Direct quantitative evaluation of H2O2 in raw, skimmed, semi-skimmed and whole milk was carried out based on a chemiluminescence reaction with luminol. For H2O2 water solutions a linear response was attained from 0.0001% to 0.007 %w/w, with a limit of detection of 3x10(-5) %w/w. A coefficient of determination, R-2, greater than 0.97 was achieved, with a relative standard deviation (RSD) not exceeding 10%. In the analyzed milk samples, the lowest H2O2 concentration detected was 0.001% w/w for raw and for skim milk and 0.002%w/w for, semi-skimmed and whole milk. The presented method is original, sensitive, rapid, and cost-effective. Due to the achieved sensitivity the method has great potential to be used for H2O2 detection in diverse areas, such as environmental monitoring and food quality.

Teses
supervisionadas

2021

Estudo de soluções de sensoriamento da humectação de folhas

Autor
Davide Miguel Costa Machado

Instituição

2021

Self-adaptive electromagnetic energy harvesting system

Autor
Pedro Miguel Rocha Carneiro

Instituição
IES_Outra

2020

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

Autor
Helena Catarina Araújo Soares Guedes Vasconcelos

Instituição
UTAD

2020

Development cost-effective solutions for multispectral interrogation of optical fibre sensors for bio-chemical applications

Autor
Paulo Sérgio Soares dos Santos

Instituição
UP-FEUP

2019

Estudo de adulteração de carne e peixe fresco

Autor
Maria João Pinho Moreira

Instituição
UTAD