Open-source digital technologies for low-cost monitoring of historical constructions

This paper shows new possibilities of using novel, open-source, low-cost platforms for the structural health monitoring of heritage structures. The objective of the study is to present an assessment of increasingly available open-source digital modeling and fabrication technologies in order to identify the suitable counterparts of the typical components of a continuous static monitoring system for a historical construction. The results of the research include a simple case-study, which is presented with low-cost, open-source, calibrated components, as well as an assessment of different alternatives for deploying basic structural health monitoring arrangements. The results of the research show the great potential of these existing technologies that may help to promote a widespread and cost-efficient monitoring of the built cultural heritage. Such scenario may contribute to the onset of commonplace digital records of historical constructions in an open-source, versatile and reliable fashion.Peer ReviewedPostprint (author's final draft

Experimental determination of satellite bolted joints thermal resistance

The thermal resistance was experimentally determined of the bolted joints of the first Brazilian satellite (SCD 01). These joints, used to connect the satellite structural panels, are reproduced in an experimental apparatus, keeping, as much as possible, the actual dimensions and materials. A controlled amount of heat is forced to pass through the joint and the difference of temperature between the panels is measured. The tests are conducted in a vacuum chamber with liquid nitrogen cooled walls, that simulates the space environment. Experimental procedures are used to avoid much heat losses, which are carefully calculated. Important observations about the behavior of the joint thermal resistance with the variation of the mean temperature are made

The use of stranded aquatic-associated bird surveys for plastic litter monitoring in Portugal

Plastics durability and persistence, combined with their high production and low rates of recovery, are causing a net accumulation of plastic debris along shorelines, surface waters, throughout the water column and in bottom sediments. Pollution by plastic debris is an increasing environmental concern all around the globe, accounting for up to 90% of marine debris. Wildlife has been severely impacted by plastic debris in coastal and aquatic environments. Macroplastics (> 20 – 100 mm) pose a health risk to several aquatic animals, including fish, turtles and birds, because of possible entanglement and ingestion. When in the environment, macroplastic debris can brittle and break through UV radiation, mechanical action and biodegradation into small sized plastic particles, designated as microplastics (1 – 5 mm), that become more bioavailable to organisms throughout the food web. However, microplastic debris can also reach aquatic environments in their original form that were manufactured for particular industrial or domestic applications, such as plastic particles used in exfoliating facial scrubs, toothpastes and resin pellets used in plastic industry. Birds are top-predators, exposed to all threats affecting these environments and this makes them ideal sentinel organisms for monitoring ecosystem changes. Considering the knowledge gap existing in southern Europe, in particular in Portugal, about the use of stranded aquatic-associated bird surveys for plastic litter monitoring, this study tries to fill this gap by: (1) set a baseline assessment of the prevalence of plastic litter affecting multispecies populations of aquatic birds in Portugal and (2) test if species, gender, age and condition of the birds influence type and quantity of ingested plastics. In this study, the plastics accumulated in the stomachs of stranded aquatic birds collected across the Portuguese territory will be quantified and characterized. A total of 310 birds samples comprising four species sourced from five different wildlife rescue centres (Parque Biológico de Gaia, CERVAS, CERAS, LxCRAS and RIAS) were collected and examined for the presence of plastic litter. Of these, 15.48% were found to ingest plastic litter. The average number and mass of ingested plastics was 1.62 items per individuals and 0.0771 g, respectively. Results show that aquatic-associated birds in Portugal do ingest plastic litter, as in many other countries in the world. Monitoring plastic litter ingested by aquatic-associated birds has the potential to be a part of a wide monitoring programme that can help to inform mitigation and management measures for aquatic litter.À medida que os plásticos se tornaram num produto indispensável no nosso quotidiano, a sua rápida produção tem sido consequentemente acompanhada por um aumento da acumulação de plásticos no meio ambiente. A durabilidade e persistência dos plásticos, combinada com a sua elevada produção e baixas taxas de recuperação, causam a acumulação de detritos plásticos ao longo das costas, águas superficiais, ao longo da coluna de água e sedimentos. A poluição por detritos plásticos é uma crescente preocupação ambiental em todo o mundo, representando cerca de 90% dos detritos marinhos. Devido ao uso excessivo e à eliminação inadequada de produtos plásticos, a vida selvagem tem sido severamente afetada pelos detritos plásticos em ambientes costeiros e aquáticos. Os macroplásticos (> 20 – 100 mm) representam uma ameaça para vários animais aquáticos, incluindo peixes, tartarugas e aves marinhas, devido à possibilidade de enredamento e ingestão. Quando no meio ambiente, os macroplásticos podem fragmentar-se através da radiação UV, ação mecânica e biodegradação em partículas plásticas mais pequenas, designadas de microplásticos (1 – 5 mm). Estas novas partículas tornam-se mais biodisponíveis para todos os organismos da cadeia alimentar e podem libertar substâncias químicas tóxicas durante o processo de degradação. As aves aquáticas são predadores expostos a todas as ameaças que afetam estes ambientes, tornando-os organismos sentinelas ideais para monitorizar mudanças nos ecossistemas

NANOTECHNOLOGY APPLIED TO DERMATOLOGY

Os últimos avanços em nanotecnologia revolucionaram os conceitos de prevenção e tratamento de algumas afeções cutâneas.O uso de nanopartículas e micropartículas em cosmética e terapêutica preventiva é cada vez mais utilizado.Menos conhecida mas muito investigada e utilizada é a aplicação de nano e micropartículas em materiais que contactam a pele, tais como vestuário, papel, equipamentos diversos, peles de animais, betão, vernizes, tintas, etc.,.The use of the latest advances in nanotechnology has revolutionized the way towards prevention and treatment of some skin affections. The use of nanoparticles and microparticles in dermatology with a cosmetic, preventive and therapeutic aim is becoming increasingly common. Less known but also thoroughly researched and used is the application of several active nano and microparticles in materials that are in contact with the skin, such as clothing, paper, various types of equipment used in everyday life, furniture, concrete, varnishes paints and so on

Mechanical characterization of aged recycled polymers and applications

The research focuses on the evaluation of mechanical properties (tension, bending, compression, impact, hardness and creep) of recycled acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) thermoplastics obtained as electronic shredder residue (ESR) from computer housings. Three forms of polymers, i.e., virgin, blend of virgin and recycled, and 100% recycled were investigated to establish their long term mechanical properties. Chopped and continuous glass fiber/fabric addition to the resins was evaluated to study the thermo-mechanical properties.;Mechanical characterization was carried out at freeze-thaw cycling aging. It was found that recycled polymers retain at least 70% of their tensile, bending and compressive strength after 18 months of aging under harsh environment (60 years in practice).;Offset block modules for highway guardrail systems were manufactured with recycled ABS and discarded rubber tires. Reinforced recycled plastic shapes were evaluated as possible post and rail for highway guardrail systems. Channel, trapezoidal, and box sections, and flat sheets made of recycled polypropylene (PP) and ABS were tested in tension, compression and bending.;Based on the manufacturing of laboratory specimens and test results, it is concluded that recycled polymers have significant potential for high-volume infrastructure and automotive applications

The Gauss map for Lagrangean and isoclinic surfaces

Simple properties of the Gauss map characterise important classes of surfaces in \Rq: $R$-surfaces, the real version of plane complex curves; Lagrangean surfaces; isoclinic surfaces

CARCINOMA EPIDERMÓIDE

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