Percorrer por autor "Fangueiro, R."
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- Antimicrobial casein/poly(vinyl alcohol) electrospun nanofibers-based dressingsPublication . Nobre, D.; Ekoh, E.; Silva, D. C.; Branco, A. C.; Pais, V.; Almeida, A.; Barroso, H.; Salema-Oom, M.; Fangueiro, R.; Colaço, R.; Galante, R.; Serro, A. P.Diabetes affects millions globally, with a rising prevalence. Chronic wounds are one of its major complications, due to the healing difficulty, highlighting the need for innovative solutions to improve the treatments efficacy. Electrospun nanofiber dressings show promising due to their ECM-like structure, oxygen permeability, and potential for bioactive functionalization. In this study, casein/poly(vinyl alcohol) (CAS/PVA) nanofibers were electrospun with antimicrobial compounds: Octiset®, polyhexanide, and ZnO particles. After crosslinking with glutaraldehyde (GA), the nanofibers mats were characterized regarding their morphology, swelling capacity, enzymatic degradation, drug release behavior, cytotoxicity, hemocompatibility, irritability potential and antimicrobial potential. They demonstrated notable swelling capacity, and therefore potential to absorb exudate and maintain a moist healing environment in the wound. Those containing polyhexanide and Octiset® (CAS/PVA_Poli and CAS/PVA_Octi) showed a significant drug release for over 4–8 h, that prolonged at a slower rate for 24 h, being mainly diffusion-controlled. The crosslinker reduced the amount of drug released and the degradation of the nanofibers but increased their water absorption capacity. CAS/PVA_Poli and CAS/PVA_Octi exhibited the most interesting set of results, as besides being non-cytotoxicity, hemocompatible and non-irritant, presented excellent antimicrobial efficacy and superior performance when compared with the crosslinked samples. They were effective against Staphylococcus aureus, Escherichia coli, and Candida albicans, and in particular against Methicillin Resistant Staphylococcus aureus and Streptococcus pyogenes which are a dangerous threat in diabetic wounds. Overall, their morphological similarity with the extracellular matrix and excellent biological properties, turns them good candidates to be used in dressings for the treatment of diabetic wounds.
- Performance assessment of waste fiber-reinforced mortarPublication . Pereira, C. Gonilho; Faria, P.; Fangueiro, R.; Martins, Ana Isabel G.; Vinagre, P.; Ratão, S.In this paper an experimental work is presented which main objective is the evaluation of the influence of different percentages of waste fibrous materials usage on the performance of fiberreinforced mortars. Moreover, the influence of binder type is evaluated. Therefore mortars were produced with two different binders – cement and powder hydrated lime. Mortars performance evaluation was carried out through flow table and plunger penetration consistency, dynamic modulus of elasticity, flexural and compressive strength, capillary absorption, drying index and adherence tests. The benefits revealed in some characteristics of both mortars by the use of waste fibers are discussed.
- Performance Assessment of Waste Fiber-Reinforced MortarPublication . Gonilho-Pereira, Cristiana; Faria, P.; Fangueiro, R.; Martins, A.; Vinagre, P.; Ratão, S.In this paper an experimental work is presented which main objective is the evaluation of the influence of different percentages of waste fibrous materials usage on the performance of fiberreinforced mortars. Moreover, the influence of binder type is evaluated. Therefore mortars were produced with two different binders – cement and powder hydrated lime. Mortars performance evaluation was carried out through flow table and plunger penetration consistency, dynamic modulus of elasticity, flexural and compressive strength, capillary absorption, drying index and adherence tests. The benefits revealed in some characteristics of both mortars by the use of waste fibers are discussed.
- Self-sensing Hybrid Composite Rod with Braided Reinforcement for Structural Health MonitoringPublication . Rosado, K.; Rana, S.; Gonilho-Pereira, Cristiana; Fangueiro, R.Enhancing the performance and lightness of different structures has already been achieved by the employment of fibre reinforced composite materials. Nowadays, a new challenging perspective is being given to these materials by the inclusion of non-metallic conductive components. This emerging technology will lead to multifunctional composites with possible applications in structural health monitoring and traffic monitoring. The aim is to avoid corrosion problems from metallic components, as well as to eliminate the need of expensive equipments used for the health monitoring of large infrastructures. In the present research, the strain-sensing capability of a core-reinforced hybrid carbon fibre/glass fibre braided composite has been investigated in order to develop continuous monitoring system. The characterization of sensing behaviour was performed with the help of an instrumental set-up capable of measuring the change in electrical resistance with mechanical stresses applied to the samples. The effect of core composition (carbon fibre/glass fibre weight ratio) on the strain sensitivity of the braided composites has been studied in order to find out the optimum composition for best sensing capability. Among the three compositions studied (23/77, 47/53 and 100/0), composites with lowest amount of carbon fibre showed the best strain sensitivity with gauge factors up to 23.4 at very low flexural strain (0.55%). Attempts have also been made in this research to develop a piezoresistive matrix for the braided composites in order to further enhance their strain sensitivity. For this purpose, the strain sensing capability of an unsaturated polyester matrix dispersed with chopped carbon fibres (1mm and 3 mm lengths) at various weight % (0.5, 0.75 and 1.25%) was evaluated in order to find out their optimum length and concentration. It was observed that chopped fibres with different lengths showed similar strain sensitivity, which however, improves with the decrease in their concentrations.
- Textile Waste Fiber-Reinforced Mortar: performance evaluationPublication . Gonilho-Pereira, Cristiana; Martins, A.; Faria, P.; Fangueiro, R.