Browsing by Author "Costa, Catarina"
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- Cork Liquefaction for Polyurethane Foam ProdutionPublication . Esteves, Bruno; Dulyanska, Yuliya; Costa, Catarina; Vicente, Jose; Domingos, Idalina; Pereira, Helena; Lemos, Luis; Cruz-Lopes, LuísaCork is one of the most important forest products in Portugal. The cork processing industry is highly resource-efficient, with the only residue, cork powder, which is too minor in quantity for agglomerate production. This work studied the usage of cork powder for the production of added-value products via polyol liquefaction. Liquefactions were performed in a reactor using a mixture of polyethylene glycol (PEG 400) and glycerol as solvents, which were catalyzed by the addition of sulphuric acid. Several cork-to-solvent ratios, reaction temperatures, and reaction times were tested. Polyurethane foams were prepared by combining polyol mixtures with a catalyst, surfactant, blowing agent, and polymeric isocyanate. Mechanical tests of the produced foams were conducted, and compressive modulus of elasticity and compressive stress at 10% deformation were determined. The results show that the best conditions for obtaining high liquefaction yields are as follows: 160 ºC for 1 h; glycerol-to-PEG 400 ratio of 1:9; cork-to-solvent ratio of 1:6; and 3% H2SO4 catalyst addition. The Fourier Transform Infrared (FTIR) spectra indicated that the lignocellulosic fractions of the cork were more selectively dissolved during acidified polyol liquefaction than the suberin. With liquefied cork powder using these optimized conditions, it is possible to produce polyurethane foams with desired properties.
- Representation of death in childrenPublication . Cunha, Madalena; Costa, Catarina; Jerónimo, Fábio; Silva, Diogo; Barbosa, Flávia; Aparicio, Graça; Campos, SofiaChild builds her own Depictions on the process of life and death with a background of life experiences. The connotations and feelings built by children about this process are determined by their developing state and naturally influenced by the education given by both parents and the society. What is the predominant Depiction of death in children from 5 to 10 years old? was our research question while aiming to analyse the Depiction that children have about death. We applied the transversal and descriptive study was made on a sample of 175 children living in Portugal, 50.29% of the children were boys and 49.71% were girls with ages comprehended between 5 and 10 years old (M=7.69years). We found out that the most of the children pledges that after death people go to hell or heaven (49.7%); they distinguish the death of people from the animal one, 51.4% state that nothing happens after death; they think that they won't feel any pain on the moment of death 52.6%, a majority on the age group 7 to 8 years, when it comes to dolls 89.7% of the children say that they don't die; 64.8% never went to a funeral, 36% don't know which is the colour of the casket and 61.7% pledges not to know what it means to grief someone; the irreversibility parameter is a majority on the age group >=9 years. The children take influence from the culture in which they live and from death experiences that they live. The results showed that their perception changes according to their developing stage.