Browsing by Author "Diz, Francisco"
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- Experimental study on 3D printing of concrete with overhangsPublication . Brun, Francis; Gaspar, Florindo; Mateus, Artur; Vitorino, João; Diz, FranciscoThe construction industry has been receiving in the recent past years the 3D printing technology as an emerging technology. Several researchers and companies have been reporting a number of case studies that show the possibilities of this technology regarding the dimensions, shape, building time, finishing and the material characteristics. It is commonly accepted that one of the big advantages of 3D printing is its possibility regarding the shape of the printed object since it can be easily changed each time a new piece is printed. This possibility raises some challenges regarding the printing limits, that are needed to the project design, such as to create overhangs. In this sense, a work was carried out to evaluate and optimize concrete printing mixtures and assess the 3D concrete printing of elements with overhangs. This paper presents the work carried out, showing the optimization of mixture composition for the binder/aggregate ratio, cement/fly ash ratio, and amount of superplasticizer and hardening accelerator, and evaluating their printing performance and mechanical properties. Printing of overhangs was possible for angles with the vertical direction till 17.5º.
- Homegreens - Aquaponics System as an Educational Tool towards a Sustainable FuturePublication . Carreira, Rute; Diz, Francisco; Pessanha, Luis; Bernardino, Raul; Franco, Inês M.; Mota, Alexandra; Faustino, Emanuel; Silva, Orlando R.; Ferreira, Susana M. F.Aquaponics is an integrated production practice that emerges from the combi-nation of two farming techniques: hydroponics and aquaculture. It consists in a simulation of a natural ecosystem that grows plants without soil substrate in the nutrient enriched waters recirculated from aquaculture systems. This type of production offers several advantages, namely economic and ecological ones. Homegreens is a project that aims to create small saltwater and freshwater aquaponic sys-tems, which can be installed in schools and serve as a didactic tool for introducing contents such as biology and sustainability to a juvenile audience. Implemented by a designers, biol-ogists and agronomists’ multidisciplinary team, the methodology was based on the develop-ment and quantitative validation of prototypes, and the installation and qualitative analyses of user’s interaction. These small scale aquaponic systems consists on a grow bed, an aquarium with a capacity for 45L, a protection barrier for the plant’s roots, aeration, biofilters and a thermostat. Sever-al simplified models were developed, presented and installed in two primary schools. Labor-atory tests were conducted to validate the use of a cork grow bed and a 3D printed polya-cid lactic (PLA) aeration and biofilter system. Children’s engagement and interaction with these simplified models, indicates that these systems will provide a biology and sustainability related group learning opportunity.