Fractal Photonic Crystal Waveguides

We propose a new class of one-dimensional (1D) photonic waveguides: the fractal photonic crystal waveguides (FPCWs). These structures are photonic crystal waveguides (PCWs) etched with fratal distribution of grooves such as Cantor bars. The transmission properties of the FPCWs are investigated and compared with those of the conventional 1D PCWs. It is shown that the FPCW transmission spectrum has self-similarity properties associated with the fractal distribution of grooves. Furthermore, FPCWs exhibit sharp localized transmissions peaks that are approximately equidistant inside the photonic band gap

Caracterización de defectos, diagnóstico y reparación de suelos de madera basado en un estudio de campo

A statistical characterization of defects in 35 buildings and 98 wood floorings (softwood and hardwood floors, and laminated and engineered wood floors), their diagnostic methods and repair solutions is presented. An expert system for inspecting wood flooring, comprising the classification of defects, their most probable causes, diagnostic methods and repair techniques, was used. Results include age, affected area, severity and frequency of defects and their main causes, as well as appropriate diagnostic methods, preventive and curative repair solutions most prescribed and the most significant correlations. Scratches were detected in more than five sixths of the sample, highly associated with exterior mechanical actions, and with an inadequate finishing layer. Wearing of the finishing layer was detected in a quarter of the inspected floorings. Accordingly, the application of a suitable finishing layer and, alternatively, its replacement are the most prescribed repair techniques.Se presenta una caracterización estadística de defectos en 35 edificios y 98 suelos de madera (sue-los de madera conífera y frondosa, pisos de madera laminada e de ingeniería de la madera), sus métodos de diagnóstico y soluciones de reparación. Se utilizó un sistema experto para inspeccionar suelos de madera, que incluía la clasificación de defectos, sus causas más probables, métodos de diagnóstico y técnicas de reparación. Los resultados incluyen edad, área afectada, gravedad y frecuencia de los defectos y sus principales causas, así como los métodos de diagnósticos apropiados, soluciones de reparación preventiva y curativa más prescritas y las correlaciones más significativas. Se detectaron arañazos en más de cinco sextos de la muestra, muy asociados con acciones mecánicas exteriores y con una capa de acabado inadecuada. El desgaste de la capa de acabado se detectó en un cuarto de los suelos inspeccionados. Por consiguiente, la aplicación de una capa de acabado adecuado y, en su caso, su sustitución son las técnicas de reparación más prescritas

Going beyond good intentions for the sustainable conservation of built heritage: a systematic literature review

This research addresses the performance gap between intentions towards a sustainable conservation of built heritage and its actual implementation. Socio-psychological models of human behaviour, such as the theory of planned behaviour (TPB), have been studying this dissonance between intention and behaviour, and allow to recognise latent critical factors. This paper provides a systematic literature review of research publications on the intersection of the topics of human behaviour, heritage, and sustainability. It aims to analyse how the TPB has been used in the field of sustainable conservation of built heritage. The studies are categorised according to the type of heritage, main actors targeted, aims, and methodology. A total of 140 publications were analysed. The results show a recent field of research. In the domain of built heritage conservation, behaviour is commonly addressed as a synonym of performance, targeting the building itself. Most publications relating socio-psychological constructs of behaviour and heritage sustainability can be found in the tourism and hospitality field, focusing on tourists’ and residents’ behaviours. The review shows that practitioners are still absent from the literature. However, research addressing other stakeholders shows that the theoretical framework can play an important role in the implementation of sustainable conservation practices in the built heritage.This research was funded by the Portuguese Foundation for Science and Technology (FCT) in the scope of the Doctoral Program Eco-Construction and Rehabilitation (EcoCoRe), to the PhD scholarship with the reference PD/BD/127853/201

Nature of the light scalar mesons

Despite the apparent simplicity of meson spectroscopy, light scalar mesons cannot be accommodated in the usual $q\bar q$ structure. We study the description of the scalar mesons below 2 GeV in terms of the mixing of a chiral nonet of tetraquarks with conventional $q\bar q$ states. A strong diquark-antidiquark component is found for several states. The consideration of a glueball as dictated by quenched lattice QCD drives a coherent picture of the isoscalar mesons.Comment: 14 pages, 1 figure, accepted for publication in Phys. Rev.

Valorisation of apple byproduct as an additive to preserve fruit quality and physiological features

info:eu-repo/semantics/publishedVersio

UHPLC-DAD-MSn analysis of phenolic compounds bioavailability throughout in vitro simulated gastrointestinal digestion

Phenolic compounds, one of the most widely distributed and structural diverse plant secondary metabolites families, have been the focus of several studies due to their vast range of biological activities (such as antioxidant, anti-inflammatory and/or antiproliferative). Since they are commonly present in human diet, phenolic compounds could be responsible for human health beneficial effects, preventing some disorders. Notwithstanding, these health effects are strictly dependent on their bioavailability, which consists in the amount of each ingested compound that reaches the target tissue where it can have a promising biological effect. Therefore, compound’s structure, human enzymatic activity and gut microbiota are some of the numerous factors that influenced phenolic compounds bioavailability, and consequently their human health beneficial effects.In this vein, the bioavailability of phenolic compounds from different classes, particularly, flavonols (rutin), flavanones (naringenin and naringin), dihydrochalcones (phloretin) and tannin monomeric units (phloroglucinol), were evaluated in an in vitro simulated gastrointestinal digestion and further analyzed and quantified through ultra-high performance liquid chromatography with diode-array detection and coupled to electrospray ionization tandem mass spectrometry (UHPLC-DAD-MSn). Most of them showed a bioavailability >70% in intestinal digestion phase and seemed to be absorbed, reaching the systemic circulation. Thus, these results could be a future remark to evaluate the human health effects of promising phenolic compounds combination, or of plant-based extracts with a similar composition or even extracts enriched with them.info:eu-repo/semantics/publishedVersio

Unusual flexibility of mesophase pitch-derived carbon materials:an approach to the synthesis of graphene

Structural flexibility in a petroleum pitch-derived carbon material has been indirectly evaluated using X-ray diffraction (XRD), immersion calorimetry and inelastic neutron scattering (INS) measurements. Exposure of the carbon material to an organic solvent (e.g., n-nonane) gives rise to a large internal rearrangement, associated with a drastic re-ordering of the graphitic microdomains. These structural changes are also associated with a high flexibility of the internal porous network, as observed by inelastic neutron scattering measurements. The internal rearrangement and the structural flexibility could be responsible for the excellent performance of this kind of activated carbons in a wide variety of adsorption processes. Last but not least, the structural characteristics of these carbon materials composed of graphitic microdomains has been used to synthesize graphene “egg-like” flakes following a simple procedure based on exfoliation with organic solvents

Synergistic effect of fibres on the physical, mechanical, and microstructural properties of aerogel-based thermal insulating renders

There is an increasing demand for highly efficient thermal insulating materials in buildings. This study presents a novel solution incorporating nanomaterials, such as silica aerogel, which can achieve low thermal conductivity values (below 0.030 W m-1 K-1) in renders. A key challenge of using aerogels is their low mechanical strength and high capillary water absorption. Here we describe a novel approach employing fibres which mitigates against some key properties which are decreased as a consequence of using aerogel. The incorporation of aramid (0.50%), sisal (0.10%), and biomass (0.10%) fibres (by total volume) was evaluated experimentally in terms of physical, mechanical, and microstructural properties. A synergistic effect between the fibres and aerogel increased mechanical resistance and a reduction in the capillary water absorption, when compared to the reference render (without fibres), whilst maintaining the low thermal conductivity. However, these properties depended significantly on whether the fibres were synthetic or organic. This study is important as it demonstrates that aerogel-based fibre-enhanced thermal renders can contribute to higher energy efficiency in both new construction and retrofitting. The use of these materials will have a direct positive impact on addressing the climate crisis

Synergistic effect of fibres on the physical, mechanical, and microstructural properties of aerogel-based thermal insulating renders

There is an increasing demand for highly efficient thermal insulating materials in buildings. This study presents a novel solution incorporating nanomaterials, such as silica aerogel, which can achieve low thermal conductivity values (below 0.030 W m-1 K-1) in renders. A key challenge of using aerogels is their low mechanical strength and high capillary water absorption. Here we describe a novel approach employing fibres which mitigates against some key properties which are decreased as a consequence of using aerogel. The incorporation of aramid (0.50%), sisal (0.10%), and biomass (0.10%) fibres (by total volume) was evaluated experimentally in terms of physical, mechanical, and microstructural properties. A synergistic effect between the fibres and aerogel increased mechanical resistance and a reduction in the capillary water absorption, when compared to the reference render (without fibres), whilst maintaining the low thermal conductivity. However, these properties depended significantly on whether the fibres were synthetic or organic. This study is important as it demonstrates that aerogel-based fibre-enhanced thermal renders can contribute to higher energy efficiency in both new construction and retrofitting. The use of these materials will have a direct positive impact on addressing the climate crisis

Mediterranean spotted fever and encephalitis: a case report and review of the literature

Mediterranean spotted fever (MSF) is a disease caused by Rickettsia conorii and transmitted by the brown dog tick Rhipicephalus sanguineus. It is widely distributed through southern Europe, Africa, and the Middle East. It is an emerging or a reemerging disease in some regions. Countries of the Mediterranean basin, such as Portugal, have noticed an increased incidence of MSF over the past 10 years. It was believed that MSF was a benign disease associated with a mortality rate of 1-3% before the antimicrobial drug era. It was called benign summer typhus. Severe forms were described in 1981, and the mortality rate reached 32% in Portugal in 1997. However, neurological manifestations associated with brain lesions are a rare event. We describe the case of a man with fever, maculopapular rash, a black spot, and hemisensory loss including the face on the left side of the body with brain lesions in the imaging studies