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Publications

Publications by CAP

2025

K-FELDSPAR GEOCHEMISTRY AS AN INDICATOR OF LITHIUM MINERALIZATION IN THE BARROSO-ALVÃO APLITE-PEGMATITE FIELD, NORTHERN PORTUGAL

Authors
Dias, F; Ribeiro, R; Gonçalves, F; Lima, A; Roda-Robles, E; Martins, T; Guimaraes, D;

Publication
CANADIAN JOURNAL OF MINERALOGY AND PETROLOGY

Abstract
Inductively coupled plasma-mass spectrometry analysis was conducted to examine the geochemical composition of Kfeldspars from various aplite-pegmatites in the Barroso-Alv & atilde;o field, focusing on the differences between Li-rich and Li-barren aplite-pegmatites. The study revealed significant variations in the concentrations of minor and trace elements (Rb, Tl, Li, Ga, Pb, Cs, Ba, Be, Ta, and Sn) present in the K-feldspars of Li-barren, spodumene-rich, and petalite-rich aplite-pegmatites. The data also indicate a geographical trend in both mineralogy and geochemistry across the aplite-pegmatites of the Barroso-Alv & atilde;o field. Li-barren aplite-pegmatites are more concentrated in the southeast, spodumene-rich dominate the center, and petalite-rich varieties are more common in the northwest. Additionally, portable X-ray fluorescence analysis was performed on the crystals of the same samples to evaluate the feasibility of in situ geochemical analysis of K-feldspars, aiming to determine whether an aplite-pegmatite can be quickly identified as Li-rich. This approach seeks to provide a rapid field assessment of whether an aplite-pegmatite justifies further exploration for Li mining. Notably, the trace amounts of Li, Sn, P, and Ta found in K-feldspars are likely due to mineral inclusions of spodumene, cassiterite, apatite, and columbite-tantalite minerals, as observed petrographically in one of these Li-rich aplite-pegmatites.

2025

Fiber Laser LIBS as a Sensing Tool for Chemical Mapping of Heritage Tiles

Authors
Capela, D; Manso, M; Lopes, T; Cavaco, R; Teixeira, J; Jorge, PAS; Silva, NA; Guimaraes, D;

Publication
29TH INTERNATIONAL CONFERENCE ON OPTICAL FIBER SENSORS

Abstract
Heritage preservation requires innovative sensing technologies to analyze their chemical composition while minimizing damage. This study introduces a Laser-induced Breakdown Spectroscopy (LIBS) system featuring a fiber laser source and optical fiber-based collection system for the analysis of heritage ceramics. Comparative experiments with a conventional Nd:YAG laser LIBS system highlight the advantages and trade-offs of the fiber laser system in terms of ablation capability, spectral mapping, and depth profiling. Results were validated against X-ray Fluorescence (XRF). Experiments demonstrate minimal surface alteration and high-quality spectral data for elements such as Pb, Fe, Zn, Sb, Mn, Ti Na, Ba and Ca. The compact design and good results position this system as a transformative tool for heritage conservation.

2025

Touch Empowerment: Self-Sustaining e-Tattoo Thermoelectric System for Temperature Mapping

Authors
Almeida, MAS; Pires, AL; Ramirez, JL; Malik, SB; de la Flor, S; Llobet, E; Pereira, AT; Pereira, AM;

Publication
ADVANCED SCIENCE

Abstract
In recent advancements within sensing technology, driven by the Internet of Things (IoT), significant impacts are observed on health sector applications, notably through wearable electronics like electronic tattoos (e-tattoos). These e-tattoos, designed for direct contact with the skin, facilitate precise monitoring of vital physiological parameters, including body heat, a critical indicator for conditions such as inflammation and infection. Monitoring these indicators can be crucial for early detection of chronic conditions, steering toward proactive healthcare management. This study delves into a thermoelectric sensor e-tattoo designed for detailed skin temperature mapping. Utilizing a novel design, this sensor detects temperature variations across thermoelectric stripes, leveraging screen-printed films of p-type Bi0.35Sb1.65Te3, n-type Bi2Te2.8Se0.2, and poly(vinyl alcohol) (PVA) for enhanced thermoelectric and flexible properties. The application of a prototype printed thermoelectric device on temporary tattoo paper, a pioneering development in wearable health technology is demonstrated. This device, validated through numerical simulations, exhibits significant potential as a non-invasive tool for temperature monitoring, highlighting its value in health diagnostics and management.

2024

Corneal Biomechanical Changes in Patients with Inherited Retinal Diseases

Authors
Marta, A; Ferreira, A; Couto, I; Neves, MM; Gomes, M; Oliveira, L; Soares, CA; Menéres, MJ; Lemos, C; Beirao, JM;

Publication
CLINICAL OPHTHALMOLOGY

Abstract
Purpose: Inherited retinal diseases (IRDs) are a group of degenerative disorders of the retina, that can be potentially associated with changes in the anterior segment, but their prevalence and impact are not known. Exploring these concomitant ophthalmologic changes with biomechanical assessment may help identify other non-retina causes of vision loss in these patients, such as corneal ectasia or susceptibility to glaucoma. This study aimed to measure and compare corneal biomechanics in patients with and without IRDs. Methods: A total of 77 patients (154 eyes) with IRD were recruited as the study group. The control group consisted of 77 healthy adults (154 eyes) with matched age and sphere equivalents. All participants underwent a comprehensive assessment including corneal tomography (Pentacam (R)) and biomechanical assessment (Corvis ST (R)). A total of 4 second-generation biomechanical parameters and 3 indexes were collected: Ambrosio Relational Thickness (ARTh), Deflection Amplitude Ratio Max (DARM), Integrated Radius (IR) and Stiffness Parameter at Applanation (SP-A1), the final deviation value D of the Belin/Ambrosio Enhanced Ectasia Display (BADResults: For IRD patients, there was a higher DARM (p < 0.001), lower ARTh (p < 0.001), higher CBI (p < 0.001), higher TBI (p<0.001), and higher BAD-D (p < 0.001) compared to the control group. Regarding discrimination of healthy subjects and IRD patients, ARTh was the most sensitive parameter. Conclusion: The results showed that IRD patients tend to have softer corneal behaviour, compared to eyes without pathology, which may predispose patients to corneal ectasia or glaucoma development. ARTh could be used to screen IRD patients if a non-retina cause of vision loss is suspected.

2024

Surface Plasmon Resonance Sensor Based on a Planar Waveguide with a Bimetallic Layer

Authors
Rodrigues, HJB; Cardoso, MP; Miranda, CC; Romeiro, AF; Giraldi, MTR; Silva, AO; Costa, JCWA; Santos, JL; Guerreiro, A;

Publication
2024 LATIN AMERICAN WORKSHOP ON OPTICAL FIBER SENSORS, LAWOFS 2024

Abstract
This paper presents the examination of a planar waveguide sensor featuring a bimetallic layer, revealing its potential applicability across both the visible and infrared spectrums. The bimetallic layer consists of adjacent gold and silver slabs positioned atop the waveguide's core. This arrangement demonstrates the activation of two distinct plasmon resonances, indicating promising prospects for multiparameter sensing applications.

2024

A century on diameter measurement techniques in cylindrical structures

Authors
Cardoso, VHR; Caldas, P; Giraldi, MTR; Cernadas, ML; Fernandes, CS; Frazao, O; Costa, JCWA; Santos, JL;

Publication
MEASUREMENT SCIENCE AND TECHNOLOGY

Abstract
This work addresses the historical development of techniques and methodologies oriented to the measurement of the internal diameter of transparent tubes since the original contributions of Anderson and Barr published in 1923 in the first issue of Measurement Science and Technology. The progresses on this field are summarized and highlighted the emergence and significance of the measurement approaches supported by the optical fiber.

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