Browsing by Author "Domingos, idalina"
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- Chemical Modification of Pachira aquatica Oil for Bio-Based Polyurethane Wood AdhesivesPublication . Silva, Emilly; Esteves, Bruno; Domingos, idalina; Almeida, Margarida Lopes de; Araújo, Bruno; Chaves, Izabella; Fassarella, Michelângelo; et al.The development of biomass-based adhesives has attracted interest as an alternative to petroleum-derived synthetic and potentially toxic adhesives. Pachira aquatica oil is a renewable raw material that can be incorporated into an MDI-based polyurethane system. In this study, the chemical composition and reactivity of P. aquatica oil were characterized using GC–MS, FTIR, and hydroxyl index measurements. The oil showed a predominance of saturated fatty acids, particularly methyl hexadecanoate (64.80%), derived from palmitic acid, and exhibited a low initial hydroxyl value. To enhance reactivity, the oil was transesterified with glycerol under different conditions, producing polyols with substantially increased hydroxyl values (412–769 mg KOH g−1 ), as confirmed by the intensified O–H and C–O bands in the FTIR spectra. The polyurethane adhesives were formulated from the selected polyols (P3 and P4) and evaluated at different NCO/OH ratios and pressing temperatures, using ABES shear tests. The highest ABES shear strength recorded was approximately 3.6 MPa, obtained for isocyanate indices between 0.8 and 1.0 and temperatures around 115 ◦C. Although this value represents the best performance among the tested conditions, it remains below the industrial benchmarks typically associated with the EN 205 standard (≈10 MPa). It is important to note that the ABES and EN 205 methods are not directly comparable due to differences in testing protocols. Nevertheless, the results indicate that, under the evaluated conditions, the adhesives exhibit limited mechanical performance and require further optimization.
- Environmental and Economic Assessment of Desktop vs. Laptop Computers: A Life Cycle ApproachPublication . Domingos Ferreira, Miguel; Domingos, idalina; Leite dos Santos, Lenise Maria; Barreto Ana; Ferreira, JoséThis study evaluates and compares the environmental and economic implications of desktop and laptop computer systems throughout their life cycles using screening life cycle assessment (LCA) and life cycle costing (LCC) methodologies. The functional unit was defined as the use of one computer system for fundamental home and small-business productivity tasks for over four years. The analysis considered the production, use, and end-of-life phases. The results showed the desktop system had a higher overall carbon footprint (679.1 kg CO2eq) compared to the laptop (286.1 kg CO2eq). For both systems, manufacturing contributed the largest share of the emissions, followed by use. Desktops exhibited significantly higher use phase emissions, due to greater energy consumption. Life cycle cost analysis revealed that laptops had slightly lower total costs (EUR 593.88) than desktops (EUR 608.40) over the 4-year period, despite higher initial investment costs. Sensitivity analysis examining different geographical scenarios highlighted the importance of considering regional factors in the LCA. Manufacturer-provided data generally showed lower carbon footprint values than the modeled scenarios. This study emphasizes the need for updated life cycle inventory data and energy efficiency improvements to reduce the environmental impacts of computer systems. Overall, laptops demonstrated environmental and economic advantages over desktops in the defined usage cases.
- Life cycle assessment of computers and electronic devices: A comprehensive review of environmental impactsPublication . Domingos Ferreira, Miguel; Domingos, idalina; Ferreira, José; IJASEATThe objective of this study was to evaluate Life Cycle Assessment studies applied to computers with respect to temporal and geographical distribution, research subjects, impact assessment methods, databases and software utilized, and principal findings. To achieve this, a bibliographical search was conducted using the Web of Science Core Collection database platform, using the keywords "Life cycle assessment" "AND" "computer" for title topic. The search yielded 12 publications selected from 28, for which a descriptive analysis was performed. It was determined that most of the studies (six in total) took place between 2011 and 2020. Geographically, the majority of these studies were conducted in Asia and the USA/Canada, with six studies in each region. The majority of studies (6) have aimed to evaluate the environmental impacts of computers (desktop/all-in-one). Regarding the impact assessment methods employed, there is considerable variation among ReciPe (2), Ecoindicator (2), IPCC (2), and CML (1), although some studies have utilized multiple methods. The primary findings indicate significant environmental benefits from adopting newer, energy-efficient technologies (APCs and LCDs), improving formal e-waste management, and focusing on recycling and sustainable manufacturing. Proper End-of-Life handling and the minimization of informal disposal also yield substantial environmental gains.
- Life Cycle Assessment of Pig Production in Central Portugal: Environmental Impacts and Sustainability ChallengesPublication . Leite dos Santos, Lenise Maria; Domingos Ferreira, Miguel; Domingos, idalina; Oliveira Verónica; Rodrigues Carla; Ferreira António; Ferreira, José; MDPIPig farming plays a crucial socioeconomic role in the European Union, which is one of the largest pork exporters in the world. In Portugal, pig farming plays a key role in regional development and the national economy. To ensure future sustainability and minimize environmental impacts, it is essential to identify the most deleterious pig production activities. This study carried out a life cycle assessment (LCA) of pig production using a conventional system in central Portugal to identify the unitary processes with the greatest environmental impact problems. LCA followed the ISO 14040/14044 standards, covering the entire production cycle, from feed manufacturing to waste management, using 1 kg of live pig weight as the functional unit. The slurry produced is used as fertilizer in agriculture, replacing synthetic chemical fertilizers. Results show that feed production, raising piglets, and fattening pigs are the most impactful phases of the pig production cycle. Fodder production is the stage with the greatest impact, accounting for approximately 60% to 70% of the impact in the categories analyzed in most cases. The environmental categories with the highest impacts were freshwater ecotoxicity, human carcinogenic toxicity, and marine ecotoxicity; the most significant impacts were observed for human health, with an estimated effect of around 0.00045 habitants equivalent (Hab.eq) after normalization. The use of more sustainable ingredients and the optimization of feed efficiency are effective strategies for promoting sustainability in the pig farming sector.
- LIFE CYCLE ASSESSMENT OF PIG PRODUCTION: A CASE STUDYPublication . Ferreira, José; Leite dos Santos, Lenise Maria; Domingos Ferreira, Miguel; OLIVEIRA VERONICA; RODRIGUES CARLA; FERREIRA ANTONIO; Domingos, idalina; IRAJPig farming plays a crucial socioeconomic role in the European Union (EU), with Germany, France, and Spain leading pork production. In Portugal, pig farming is vital for regional development and national economy. To ensure future sustainability, it is essential to identify the pig production activities that have the most significant environmental impacts. This study carried out a Life Cycle Assessment (cradle-to-gate) of pig production using a conventional system in central Portugal to identify the phases with the greatest environmental impact. LCA followed the ISO 14040/14044 standards, covering the production cycle, using 1 kg of live pig weight as a functional unit. The analyzed scenario encompasses everything from the production and growth of piglets to the pig fattening phase, including the formulation of specific feed for each stage of development, transport of inputs, use of diesel to generate electricity in the facilities, and management of pig manure. The results highlight feed production and piglet management as the most important steps. The study highlights the importance of sustainable practices in order to mitigate environmental issues such as human carcinogenic toxicity and the ecotoxicity of freshwater and marine water, emphasizing the need for improved strategies in pig farming.
- Olive Tree (Olea europaea) Pruning: Chemical Composition and Valorization of Wastes Through LiquefactionPublication . Domingos, idalina; Domingos Ferreira, Miguel; Ferreira, José; Esteves, BrunoOlive tree branches (OB) and leaves (OL) from the Viseu region (Portugal) were studied for their chemical composition and liquefaction behavior using polyalcohols. Chemical analysis revealed that OL contained higher ash content (4.08%) and extractives, indicating more bioactive compounds, while OB had greater α-cellulose (30.47%) and hemicellulose (27.88%). Lignin content was higher in OL (21.64%) than OB (16.40%). Liquefaction experiments showed that increasing the temperature from 140 ◦C to 180 ◦C improved conversion, with OB showing a larger increase (52.5% to 80.9%) compared to OL (66% to 72%). OB reached peak conversion faster, and the optimal particle size for OB was 40–60 mesh, while OL performed better at finer sizes. OL benefited more from higher solvent ratios, whereas OB achieved high conversion with less solvent. FTIR analysis confirmed that acid-catalyzed liquefaction breaks down lignocellulosic structures, depolymerizes cellulose and hemicellulose, and modifies lignin, forming hydroxyl, aliphatic, and carbonyl groups. These changes reflect progressive biomass degradation and the incorporation of polyalcohol components, converting solid biomass into a reactive, polyol-rich liquid. The study highlights the distinct chemical and processing characteristics of olive branches and leaves, informing their potential industrial applications.
- Olive Tree (Olea europaea) Pruning: Chemical Composition and Valorization of Wastes Through LiquefactionPublication . Domingos, idalina; Domingos Ferreira, Miguel; Ferreira, José; Esteves, Bruno; MDPIOlive tree branches (OB) and leaves (OL) from the Viseu region (Portugal) were studied for their chemical composition and liquefaction behavior using polyalcohols. Chemical analysis revealed that OL contained higher ash content (4.08%) and extractives, indicating more bioactive compounds, while OB had greater α-cellulose (30.47%) and hemicellulose (27.88%). Lignin content was higher in OL (21.64%) than OB (16.40%). Liquefaction experiments showed that increasing the temperature from 140 ◦C to 180 ◦C improved conversion, with OB showing a larger increase (52.5% to 80.9%) compared to OL (66% to 72%). OB reached peak conversion faster, and the optimal particle size for OB was 40–60 mesh, while OL performed better at finer sizes. OL benefited more from higher solvent ratios, whereas OB achieved high conversion with less solvent. FTIR analysis confirmed that acid-catalyzed liquefaction breaks down lignocellulosic structures, depolymerizes cellulose and hemicellulose, and modifies lignin, forming hydroxyl, aliphatic, and carbonyl groups. These changes reflect progressive biomass degradation and the incorporation of polyalcohol components, converting solid biomass into a reactive, polyol-rich liquid. The study highlights the distinct chemical and processing characteristics of olive branches and leaves, informing their potential industrial applications.
- Valorization of Arbutus unedo L. Bark Through Chemical Composition Analysis, Liquefaction, and Bio-Based Foam ProductionPublication . Cruz-Lopes, Luísa; Dulyanska, Yuliya; Lopes, Rogério; Domingos, idalina; Ferreira, José; Esteves, BrunoArbutus unedo (strawberry tree) is a small Mediterranean tree capable of vigorous regrowth after disturbances like fire. Traditionally used for biomass fuel, its bark and branches hold potential for higher-value products through ecovalorization into liquid mixtures that could replace petroleum-based materials. This study aimed to explore the chemical composition of various components of Arbutus unedo and to produce a liquefied material from its internal (IB) and external bark (EB). Chemical compositions of internal and external bark were determined using TAPPI standards including ash, extractive content, lignin, and cellulose. Metal cations were analyzed by ICP. Liquefaction of bark was optimized in a PARR reactor, evaluating factors such as particle size, temperature, and time, and the best polyols were monitored by FTIR-ATR. Polyurethane foams were made with internal and external bark materials liquefied by polymerization with isocyanate, a catalyst, and water as a blowing agent. Results showed that EB has a higher extractive and lignin content, while IB contains more cellulose. Liquefaction yields were higher for IB (74%) than EB (68%), with IB yielding polyols that produced stronger and more resilient foams with higher compressive strength and modulus of elasticity. Mechanical properties of the foams were influenced by the NCO/OH ratio and catalyst levels. Overall, the internal bark demonstrated superior performance for foam production, highlighting its potential as an eco-friendly alternative to petroleum-derived materials.