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Faria, P., P. Duarte, D. Barbosa, and I. Ferreira, "New composite of natural hydraulic lime mortar with graphene oxide", Constr Build Mater, vol. 156, pp. 1150-1157, 2017. AbstractDOI

Recent studies show the incorporation of graphene oxide (GO) in cement composites. But these composites are frequently incompatible with original materials for building rehabilitation. To overcome this limitation, natural hydraulic lime mortars were used as matrix, and the influence of GO percentage and type of mixing was investigated. The influence on the microstructure, mechanical and physical properties was assessed. The best results were obtained with dispersed GO at concentrations of 0.05% and 0.1%. A slight improvement of mechanical and physical characteristics was achieved. This could lead to new mortars with improved properties that can be used for building rehabilitation.

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Echeverria, C., P. Soares, A. Robalo, L. Pereira, C. M. M. Novo, I. Ferreira, and J. P. Borges, "One-pot synthesis of dual-stimuli responsive hybrid PNIPAAm-chitosan microgels", Mater. Des, vol. 86, pp. 745-751, 2015. AbstractDOI

The incorporation of magnetic nanoparticles into poly(N-isopropylacrylamide) (PNIPAAm) and chitosan microgels gives rise to hybrid systems that combine the microgels swelling capacity with the interesting features presented in magnetic nanoparticles. The presence of chitosan that act as surfactant for magnetic nanoparticles provides a simplistic approach which allows the encapsulation of magnetic nanoparticles without any previous surface modification. Spherical and highly monodisperse microgels with diameters in the range of 200 to 500 nm were obtained. The encapsulation of magnetic nanoparticles in the polymer matrix was confirmed by high resolution Scanning Electron Microscopy in transmission mode. Volume phase transition of the microgels was accessed by Dynamic Light Scattering measurements. It was observed that the thermosensitivity of the PNIPAM microgels still persists in the hybrid microgels; however, the swelling ability is compromised in the microgels with highest chitosan content. The heating performance of the hybrid magnetic microgels, when submitted to an alternating magnetic field, was also evaluated demonstrating the potential of these systems for hyperthermia treatments.

Figueira, J., J. Loureiro, J. Marques, C. Bianchi, P. Duarte, M. Ruoho, I. Tittonen, and I. Ferreira, "Optimization of Cuprous Oxides Thin Films to be used as Thermoelectric Touch Detectors", ACS Appl Mater Interfaces, vol. 9, issue 7, pp. 6520-6529, 2017. AbstractDOI

The electronic and optical properties of p-type copper oxides (CO) strongly depend on the production technique as it influences the obtained phases: cuprous oxide (Cu2O) or cupric oxide (CuO), the most common ones. Cu films deposited by thermal evaporation have been annealed in air atmosphere, with temperature between 225 and 375 °C and time between 1 and 4 h. The resultant CO films have been studied to understand the influence of processing parameters in the thermoelectric, electrical, optical, morphological, and structural properties. Films with a Cu2O single phase are formed when annealing at 225 °C, while CuO single phase films can be obtained at 375 °C. In between, both phases are obtained in proportions that depend on the film thickness and annealing time. The positive sign of the Seebeck coefficient (S), measured at room temperature (RT), confirms the p-type behavior of both oxides, showing values up to 1.2 mV·°C–1and conductivity up to 2.9 (Ω·m)−1. A simple detector using Cu2O have been fabricated and tested with fast finger touch events

Castro, D., P. Jaeger, A. C. Baptista, and J. P. Oliveira, "An Overview of High-Entropy Alloys as Biomaterials", Metals, vol. 11, pp. 648, 2021.
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Morawiec, S., M. J. Mendes, S. A. Filonovich, T. Mateus, S. Mirabella, H. Águas, I. Ferreira, F. Simone, E. Fortunato, R. Martins, F. Priolo, and I. Crupi, "Photocurrent enhancement in thin a-Si: H solar cells via plasmonic light trapping", CLEO: Science and Innovations: Optical Society of America, 8-13 Jun, 2014. Abstract

Photocurrent enhancement in thin a-Si:H solar cells due to the plasmonic light trapping is investigated, and correlated with the morphology and the optical properties of the self-assembled silver nanoparticles incorporated in the cells’ back reflector.

Honnet, C., H. Perner-Wilson, M. Teyssier, B. Fruchard, J. Steimle, A. C. Baptista, and P. Strohmeier, "PolySense: Augmenting Textiles with Electrical Functionality using In-Situ Polymerization", Proceedings of the 2020 CHI Conference on Human Factors in Computing Systems, 2020.
Strohmeier, P., C. Honnet, H. Pernet-Wilson, M. Teyssier, B. Fruchard, A. C. Baptista, and J. Steimle, "PolySense: How to Make Electrically Functional Textiles", CHI Conference on Human Factors in Computing Systems , 2020.
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Contreras, J., J. Tornero, I. Ferreira, R. Martins, L. Gomes, and E. Fortunato, "Simulated and Real Sheet-of-Light 3D Object Scanning Using a-Si:H Thin Film PSD Arrays", Sensors, vol. 15, issue 12, pp. 29938-29949, 2015. Abstract

A MATLAB/SIMULINK software simulation model (structure and component blocks) has been constructed in order to view and analyze the potential of the PSD (Position Sensitive Detector) array concept technology before it is further expanded or developed. This simulation allows changing most of its parameters, such as the number of elements in the PSD array, the direction of vision, the viewing/scanning angle, the object rotation, translation, sample/scan/simulation time, etc. In addition, results show for the first time the possibility of scanning an object in 3D when using an a-Si:H thin film 128 PSD array sensor and hardware/software system. Moreover, this sensor technology is able to perform these scans and render 3D objects at high speeds and high resolutions when using a sheet-of-light laser within a triangulation platform. As shown by the simulation, a substantial enhancement in 3D object profile image quality and realism can be achieved by increasing the number of elements of the PSD array sensor as well as by achieving an optimal position response from the sensor since clearly the definition of the 3D object profile depends on the correct and accurate position response of each detector as well as on the size of the PSD array.

Ferreira, M., J. Loureiro, A. Nogueira, A. Rodrigues, R. Martins, and I. Ferreira, "SnO2 thin Film Oxides Produced by rf Sputtering for Transparent Thermoelectric Devices", Mater. Today-Proc, vol. 2, issue 2, pp. 647-653, 2015. AbstractDOI

The combination of high transparency and good thermoelectric properties of SnO2 can open new field of applications for the thin film thermoelectric materials. Here we report on SnO2 thin films with transmittance above 90%, resistivity bellow 10-3 Ωm and a Power Factor around 10-4 W/m.K2, for a Seebeck of -255 μV/K, at room temperature. The effect of film thickness and post-deposition annealing on the thermoelectric properties were analysed. The performances of a single layer thermoelectric device are also presented.

Marques, A. C., J. Faria, P. Perdigão, B. M. M. Faustino, R. Ritasalo, K. Costabello, R. C. da Silva, and I. Ferreira, "Stability under humidity, UV-light and bending of AZO films deposited by ALD on Kapton", Scientific Reports, vol. 9, pp. 17919, 2019.