Percorrer por autor "Dias, C."
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- A finite element method to study multimaterial wind towersPublication . Pascoal-Faria, P.; Dias, C.; Oliveira, M; Alves, N.Wind towers are used to produce electrical energy from the wind. A significant number of towers is manufactured using tubular separately steel or concrete, having limitations such as maximum diameter and height imposed essentially by transportation limitations. Developed computational studies on structural design of towers have been mainly focused on a single material. This investigation aims to develop a finite element method able to study structural design of wind towers combining different materials. The finite element model combines solid and shell elements encompassing different geometries. Several case studies are considered to validate the proposed method and accurate results are obtained.
- Preliminary results on the effect of 1-naphthaleneacetic acid on restoring ‘Rocha’ pear ripening treated with 1-MCPPublication . Dias, C.; Rodrigues, A.C.; Vasconcelos, M.W.; Ferrante, A.; Pintado, M.Loss of ripening capacity is still a major problem associated with the use of 1-methylcyclopropene (1-MCP), despite its benefit in preserving climacteric fruit under long-term cold storage, specially, in controlled atmosphere. Several strategies have been tested to overcome this problem, namely the use of phytohormones (e.g., ethylene). In this study, ‘Rocha’ pear treated with 1-MCP was after storage exposed to a synthetic phytohormone, the auxin 1-naphthaleneacetic acid (1-NAA) at 2 mM, for 2 h. Before treatment, as well as 3, 6 and 24 h after treatment, the primary impact of 1-NAA on the expression of genes encoding ethylene receptor (PcETR2) and ethylene biosynthesis enzyme (PcACS4) was determined. The restoration of ripening capacity was assessed across shelf-life by measuring ethylene production and 1-aminocyclopropane-1-carboxyl acid oxidase (ACO) activity. Herein, the expression of PcACS4 significantly increased in pears treated with 1-NAA compared to pear treated only with 1-MCP. Additionally, the expression of PcETR2 was enhanced, revealing the potential of the 1-NAA treatment in inducing the production of new ethylene receptors. Time course physicochemical analysis revealed that fruit ripening was promoted by 1-NAA treatment, as judged by the higher ethylene production (ca. 50%) and ACO activity (ca. 15%) compared to treated only with 1-MCP. The application of the auxin indicated its potential in reactivating the ripening of ‘Rocha’ pear under the effect of 1-MCP.