Browsing by Author "Pinto, Tiago"
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- Design of context-aware information systems in manufacturing industries: overview and challengesPublication . Santos, Arlindo; Lima, Cláudio; Reis, Arsénio; Pinto, Tiago; Nogueira, Paulo; Barroso, João ManuelIn the last 30 years, several academic and commercial projects have explored the context-awareness concept in multiple domains. The concepts of ubiquitous computing and ambient intelligence are features associated with the fourth generation industry empowering space with the ability to interact and re-spond appropriately according to context. In the scope of Industry 4.0, context-aware systems aim to improve productivity in smart factories and offer assistance to workers through services, applications, and devices, delivering functionalities and contextualized content. This article, through descriptive research, discusses the concepts related to context, presents and analyses projects related to ubiqui-tous computing and associated with Industry 4.0, and discusses the main chal-lenges in systems and applications development to support intelligent environ-ments for increased productivity, supporting informed decision-making in the factories of the future. The study results indicate that many research questions regarding the analysed projects remain the same, leading the research in the con-text-ware systems area to minimize issues related to context-aware features, im-proving the incorporation of Industry 4.0 paradigm concepts.
- Dimensional stability of wood in presence of waterPublication . Ferreira, Débora; Pinto, Cristiana; Borges, Paula; Pinto, Tiago; Fonseca, E.M.M.Wood is our most important raw material. It is important not only because it is used for literally hundreds of products, but also because it is a renewable natural resource. Through a carefully and planned use, forests could provide a perpetual supply of wood. All wood in growing trees contains a considerable amount of water as part of the photosynthesis and the growing processes. This water is commonly called sap. The main goal of this work is to study the water movement in wood: first of all, the drying process, which occurs before the manufacture and use as finished wood products, and secondly the gain and loss of water in response to changes in environmental conditions that surround the wood. The moisture content relationship has an important influence on wood properties and performance. Wood is dimensionally stable when moisture content is greater than the fibre saturation point (MCfs). Below MCfs wood dimensional changes and it gains moisture (swells) or loses moisture in the form of bound water. The level of MCfs depends on the relative humidity and temperature of the surrounding air. Shrinkage and swelling are the cause of many of the problems that occur in wood during drying and in use, therefore, an understanding of them will help minimize such problems. Splitting, warping, and open joints are examples of problems that occur due to uneven shrinkage. An experimental program was defined with the aim to evaluate the dimensional stability of hardwood and softwood species. The Pine softwood and the Ash hardwood of the North-east region of Portugal will be analysed. A group of thirty specimens were made for each specimens of wood. The assumed geometry for the specimens is 40×40×10 mm, based on NP EN 614 recommendations. Before running the tests, one half of the specimens of each species were dried in an oven at 103ºC ± 2ºC, while the other one half was saturated in a water tank until a constant mass is attained. The tests were carried out in a climatic chamber with a constant internal environment of 20ºC and 60% (RH), during a period time equal to 24 hours or more, until stabilization of dried and saturated specimens. Mass is considered constant when the difference between two consecutive weight measurements, delayed 2 hours, is less than 0.5%.
- Estabilidade dimensional da madeira na presença de águaPublication . Ferreira, Débora; Pinto, Cristiana; Borges, Paula; Pinto, Tiago; Fonseca, E.M.M.A madeira é um material higroscópico, cujas propriedades físicas e mecânicas dependem do teor em água. Sendo um material natural exibe uma heterogeneidade significativa e por ter uma estrutura celular, apresenta uma anisotropia acentuada. Um dos principais problemas da madeira está relacionado com o fenómeno de inchamento e retração devido à presença de humidade relativa do ar. O controlo do teor de humidade da madeira, no momento em que se aplica, contribui para minimizar os problemas da sua variação dimensional. Um dos objetivos deste trabalho foi o de compreender a relação da água com duas espécies diferentes de madeira, o Pinho e o Freixo, através de uma metodologia experimental. Foram conduzidos diversos ensaios para o estudo da estabilidade dimensional, atendendo aos fenómenos de retração e inchamento da madeira. A determinação do teor em água e da massa volúmica foi efetuada em conformidade com as normas NP EN 614:1973 e NP 616:1973 do LNEC [1,2], respetivamente. Os provetes analisados foram obtidos a partir de madeira sã e isenta de nós, fendas ou outros defeitos, com forma cúbica e de dimensão igual a 40×40×10mm.
- Thermal performance characterization of cement-based lightweight blocks incorporating textile wastePublication . Briga-Sá, Ana; Gaibor, Norma; Magalhães, Leandro; Pinto, Tiago; Leitão, DinisTextile industry is one of the most important sectors of the global economy, but at the same rate as production, millions of tons of textile waste (TW) are generated worldwide, causing negative impacts on the environment. To mitigate CO2 emissions and TW landfilled, its reuse and recycling are considered promising in fulfilling the circular economy principles. Furthermore, its valorization as building materials components may be a contribution towards sustainable construction. Studies already developed in this domain demonstrate that more research work is needed so the suitability of TW as building insulation materials can be assessed. In this context, it is intended with the research work here presented to propose cement-based lightweight blocks (LWB) incorporating TW and discuss their application as insulation materials purposes. The studied TW was fabric leftovers from the textile industry, constituted by 70 % wool, 25% viscose, and 5% elastane. TW percentages of 6.25%, 8.16%, and 8.75% were considered in the cement mixture composition of LWB1, LWB2 and LWB3, respectively, and their influence on the LWB thermal performance was analyzed. The LWB thermal performance characterization was carried out by analyzing heat fluxes, inner surface temperatures, thermal transmission coefficients, and infrared thermal imaging. The obtained results revealed their suitability for thermal insulation applications. Values of 0.34 m2◦C/W, 0.61 m2◦C/W, and 0.67 m2◦C/W were estimated for the thermal resistance of LWB1, LWB2 and LWB3, respectively, achieving higher thermal stability when higher percentage of TW is incorporated in the cementitious mixture composition. A comparison of the LWB with currently available building materials, such as simple masonry walls and insulating concrete forms, was also performed showing promising results for the proposed textile waste-based materials.