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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.
- Polyurethane Foams from Liquefied Eucalyptus globulus BranchesPublication . Domingos, Idalina; Fernandes, Ana Paula; Ferreira, José; Cruz-Lopes, Luísa; Esteves, BrunoCurrently, polyurethane (PU) production is completely dependent upon fossil oil, as the two primary reagents necessary for PU production, polyol and isocyanate, are derived from fossil fuels. Eucalyptus branches are waste products for most forest management companies. In this work, polyols obtained by the liquefaction of eucalyptus branches were used for foam production. The influence of the isocyanate, catalyst, surfactant, and blowing agent contents on the foam properties was studied. Overall the amount of each chemical used in the production of PU foams had a noticeable effect on the density and compressive properties. The amount of water (blowing agent) had the strongest effect and decreased the density and compressive properties because of higher foam expansion. The other chemicals increased or decreased the density and compressive stress depending on the amount used. The density of the produced foams ranged from 36 kg/m3 to 108 kg/m3, the compressive stress ranged from 15 kPa to 149 kPa, and the Young’s modulus ranged from 64 kPa to 2100 kPa. The results showed that it is possible to convert these forest residues into PU foams with properties somewhat similar to those of commercial foams, although with a lower compressive strength.
- The contribution of a portion of meat, fish and eggs for climate changePublication . Ferreira, Vicente; Domingos, Idalina; Esteves, Bruno; Cruz-Lopes, LuísaIntrodução: A mudança nos padrões alimentares dos cidadãos implicará uma pegada ambiental maior em termos de emissões de gases de efeito estufa e uso de recursos naturais. Por exemplo, dietas ricas em leite e carne, especialmente de ruminantes, estão associadas ao aumento das emissões de metano da fermentação entérica, do dióxido de carbono da deflorestação para dar origem ao pasto e do óxido nitroso da produção de ração. Objetivos: Para um consumo mais sustentável, o objetivo deste estudo foi quantificar e comparar a contribuição para as alterações climáticas de uma porção do que se come em geral, proveniente da Roda dos Alimentos, relacionados com carnes, aves, peixes e ovos, para alcançar uma dieta equilibrada e saudável. Métodos: A Avaliação do Ciclo de Vida, baseada nas normas ISO 14040/44 (2006), foi a metodologia utilizada. A análise de inventário e, posteriormente a análise de impacte foram realizadas utilizando o software SimaPro 8.5. O método escolhido para a avaliação de impacte ambiental foi o IPCC 2013 GWP 100a. Resultados: Os resultados mostram que uma porção de cavala (peixe) apresenta a pegada ecológica inferior seguida da porção de bacalhau, frango, lombo de porco, ovos, lagosta e bife de vaca, respetivamente. Conclusões: A principal conclusão deste estudo é que a avaliação do impacte de ciclo de vida usando o método IPCC 2013 GWP 100a, pode ajudar as pessoas a escolherem os melhores alimentos para uma refeição mais amiga do ambiente, ajudando a mitigar as alterações climáticas.
- Proof-of-Principle That Cellular Automata Can Be Used to Predict Infestation Risk by Reticulitermes grassei (Blattodea: Isoptera)Publication . Sequeira, João G. N.; Nobre, Tânia; Duarte, Sónia; Jones, Dennis; Esteves, Bruno; Nunes, LinaOver the past few decades, species distribution modelling has been increasingly used to monitor invasive species. Studies herein propose to use Cellular Automata (CA), not only to model the distribution of a potentially invasive species but also to infer the potential of the method in risk prediction of Reticulitermes grassei infestation. The test area was mainland Portugal, for which an available presence-only dataset was used. This is a typical dataset type, resulting from either distribution studies or infestation reports. Subterranean termite urban distributions in Portugal from 1970 to 2001 were simulated, and the results were compared with known records from both 2001 (the publication date of the distribution models for R. grassei in Portugal) and 2020. The reported model was able to predict the widespread presence of R. grassei, showing its potential as a viable prediction tool for R. grassei infestation risk in wooden structures, providing the collection of appropriate variables. Such a robust simulation tool can prove to be highly valuable in the decisionmaking process concerning pest management.
- Water-related properties of Pinus pinaster wood treated by different methodsPublication . Domingos, Idalina; Ferreira, José; Cruz-Lopes, Luísa; Esteves, BrunoA study was made of water-related properties of Pinus pinaster wood impregnated with paraffin or modified by heat treatment or furfurylation. Treated woods were submerged in water for periods ranging from 2 to 1680 hours. Water absorption, swelling, and dimensional stability in the radial and tangential directions – expressed as Anti-Shrinking Efficiency (ASE) – were determined. Water absorption increased with time, reaching approximately 140% after 1680 h for untreated and heat-treated wood, and 60% for paraffinated and furfurylated wood. The rate of swelling differed between the first hours of soaking and after prolonged immersion. The final swelling was approximately 9% and 6% for untreated pine, 8% and 4% for paraffinated pine, 5.5% and 3% for heat-treated pine and 2.5% and 1% for furfurylated pine (in the tangential and radial directions respectively). At the end of the soaking test, furfurylated pine had the best ASE of approximately 80% and 70% in the tangential and radial directions respectively, followed by heat-treated pine with 44% and 34%, and paraffinated wood with 35% and 13%. [
- Enhancing Liquefaction Efficiency: Exploring the Impact of Pre-Hydrolysis on Hazelnut Shell (Corylus avellana L.)Publication . Cruz-Lopes, Luísa; Duarte, Joana; Dulyanska, Yuliya; Guiné, Raquel; Esteves, BrunoHazelnut shells (HS), scientifically known as Corylus avellana L. shells, are waste produced by companies that process nuts. The main objective of this study was to find an efficient way to maximize the chemical potential of HS by solubilizing the hemicelluloses, which could then be used to recover sugars and, at the same time, increase the lignin content of this material to produce adhesives or high-strength foams. In order to optimize the pre-hydrolysis process, two different temperatures (160 and 170 °C) and times varying from 15 to 180 min were tested. All the remaining solid materials were then liquefied using polyalcohols with acid catalysis. The chemical composition of hazelnut shells was determined before and after the pre-hydrolysis. All of the process was monitored using Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR) by determining the spectra of solids and liquids after the pre-hydrolysis and liquefaction steps. The highest solubilization of hazelnut shells was found for 170 °C and 180 min, resulting in a 25.8% solubilization. Chemical analysis after the hydrolysis process showed a gradual increase in the solubilization of hemicelluloses as both the temperature and time of the reactor were increased. Simultaneously, the percentages of α-cellulose and lignin in the material also increased with rises in temperature and duration. FTIR-ATR allowed for the detection of significant spectral changes in the hazelnut shells from their initial state to the solid residue and further into the liquefied phase. This confirmed that pre-hydrolysis was effective in enhancing the chemical composition of the material, making it more suitable for the production of adhesives, polyurethane foams, or in the production of bioplastics and composite materials, combined with other biopolymers or synthetic polymers to enhance the mechanical properties and biodegradability of the resulting materials.
- Edible Insects: Perceptions of Marketing, Economic, and Social Aspects among Citizens of Different CountriesPublication . Guiné, Raquel; Florença, Sofia De Guiné E; Costa, Cristina Amaro Da; Correia, Paula; Cruz-Lopes, Luísa; Esteves, Bruno; Ferreira, Manuela; Fragata, Anabela; Cardoso, Ana Paula; Campos, Sofia; Anjos, Ofélia; Bartkiene, Elena; Djekic, Ilija; Matran, Irina M.; Čulin, Jelena; Klava, Dace; Chuck-Hernández, Cristina; Korzeniowska, Malgorzata; Boustani, Nada M.; Papageorgiou, Maria; Gutiérrez, Bernardo Prieto; Černelič-Bizjak, Maša; Damarli, Emel; Ferreira, VanessaBecause edible insects (EI) have been, in recent years, recommended as a nutritious animal protein food with enormous environmental advantages over other sources of animal protein for human consumption, studies aimed at investigating the consumer perspective have become more prominent. Hence, this study intended to examine the perceptions of participants from different countries about the commercialization and economic and social impacts of edible insects. The study was made using a questionnaire survey, and data were collected in Brazil, Croatia, Greece, Latvia, Lebanon, Lithuania, Mexico, Poland, Portugal, Romania, Serbia, Slovenia, Spain, and Turkey. The final number of received answers was 7222 participants. For the treatment of the results, different statistical techniques were used: factor analysis, internal reliability by Cronbach’s alpha, cluster analysis, ANOVA to test differences between groups, and Chi-square tests. The results obtained confirmed the validity of the scale, constituted by 12 out of the 14 items initially considered, distributed by 4 factors: the first related to the economic impact of EIs, the second related to the motivation for consumption of EIs, the third related to the places of purchase of EIs, and the fourth corresponding to a question presented to the participants as a false statement. A cluster analysis allowed identifying three clusters, with significant differences between them according to all the sociodemographic variables tested. Also, it was found that the participants expressed an exceptionally high level of agreement with aspects such as the difficulty in finding EIs on sale, knowledge acting as a strong motivator for EI consumption, and the role of personalities and influencers in increasing the will to consume EIs. Finally, practically all sociodemographic variables were found to be significantly associated with perceptions (country, sex, education, living environment, and income), but not age. In conclusion, the perceptions about EI commercialization were investigated and revealed differences among samples originating from different countries. Moreover, the sociodemographic characteristics of the participants were found to be strongly associated with their perceptions.
- Determination of some wood properties and response to weathering of Citrus limon (L.) Burm woodPublication . Şahin, Sırrı; Ayata, Umit; Bal, Bekir Cihad; Esteves, Bruno; Can, Ahmet; Sivrikaya, HüseyinOrange is a fruit of the Citrus genus in the family Rutaceae. It is assumed to have originated in southern Asia, and to have been first cultivated in China around 2500 BC. There is little knowledge on the quality of wood from orange trees, which is occasionally used in fine woodwork, tool handles, mosaics, and marquetry. This work aimed to evaluate the possibility of using orange wood from agricultural conversions and orchard plantation renewals to make products with a high value. Logs from plantations located in southern Italy were collected, and the key aspects for determining the suitability of using the wood as flooring were examined. Laboratory tests were carried out to determine the shrinkage, dimensional stability, and surface hardness, which included an indentation test on the wood flooring. Drying trials were also performed, and prototypes of flooring were prepared so professionals and end users could evaluate the aesthetic value. The results confirmed that the wood from orange trees is fine-grained, and is characterized by a high density and shrinkage, average dimensional stability, and high surface hardness. The results of the tests suggested performing careful drying and following specific procedures according to the size of the elements. The wood was highly appreciated by the users, which confirmed the possibility of using this wood as a renewable raw material, despite the limited availability, for manufacturing high-quality products.
- Agro-industrial wastes as building insulation materials: A review and challenges for Euro-Mediterranean countriesPublication . Cintura, Eleonora; Nunes, Lina; Esteves, Bruno; Faria, PaulinaThis study investigates the possibility of using agro-industrial wastes for building products, mainly focusing on their insulation properties. A classification of bio-wastes is provided, namely of the lignocellulosic ones and their features and properties are described. Information about three main topics is collected: world production and consumption of some crops already used as building materials, their chemical composition and their most studied properties. Since the considered materials are lignocellulosic and they have many common features, a com- parison is made. The aim is to have comparable information to support future research related to the production of eco-efficient indoor insulation boards. The result of this research is the choice of four different agro-industrial wastes produced in the Euro-Mediterranean Countries. This area was chosen as buildings typically have little or no insulation due to the regional mild climate; however, particularly with climate change, indoor hygrothermal comfort is poor. The collection of information allows some conclusions to be reached about the different bio- wastes already studied and identify gaps in the literature.
- Densification and heat treatment of maritime pine woodPublication . Esteves, Bruno; Ribeiro, Fábio; Cruz-Lopes, Luísa; Ferreira, José; Domingos, Idalina; Duarte, Marta; Duarte, Sónia; Nunes, LinaPine (Pinus pinaster Ait.) wood samples were subjected to a combined treatment by densification and heat treatment. Samples were densified before and after heat treatment. The heat treatment was made inside an oven at 190ºC during 2 to 6 h and wood densification was made in a hot press at around 48 bar pressure and temperatures between 160ºC and 200ºC for 30 min. Compression-set, compression-set recovery after three cycles of water soaking followed by oven drying, density, hardness, bending strength and stiffness and durability against subterranean termites were determined after the treatment. Results show that densification increases density, hardness, bending strength, stiffness and durability against termites. Heat treatment applied after the densification is more effective in reducing compression-set recovery than if applied before.