Browsing by Issue Date, starting with "2025-02"
Now showing 1 - 9 of 9
Results Per Page
Sort Options
- Gemological analysis of ruby origins: a case studyPublication . Oliveira, Isaac Gomes de; Cardoso, Jessica de Sousa; Franco, Julia; Santos, Breno Ravielly dos; Silva, Suely Andrade da; Santos, Lucilene; Mattos, Irani Clezar; Neri, Tereza Falcão de OliveiraABSTRACT: Gemstones are substances of natural, artificial or synthetic origin, which due to their hardness, rarity, uniqueness, diaphaneity and beauty are used as adornments. In the market, ruby is the second most expensive type of gemstone. Depending on its size, it can exceed the value of the diamond, besides being the most valuable colored gem in the market. It is a variety of the mineral corundum, just like sapphire, and it is a form of crystallized alumina (Al2O3) and the responsible for its red color is chromium. There are deposits in many different places around the world, being common the practice of speculating the origin of the ruby based on the shade of red. Provenance strongly impacts the commercial value of the gem. Several faceted rubies were donated to the Federal University of Ceará. This project aims to discover from what regions (countries) the donated rubies are coming, using gemological characteristics. To establish the origin of the specimen collection, the following methods and equipment were used: bibliographic research about rubies characteristics, refractometer to measure refractive indexes, dichroscope for pleochroism analysis, ultraviolet lamp (UV) for determination of fluorescence, and especially the gemological (stereoscopic) microscope to study the types of inclusions in transparent to translucent rubies. Using the methods cited, it was possible to produce, successfully, the gemological characterization of the specimens and deduce, based on strong evidence, what was the geographic origin of the studied specimens. Through microscopy it was deduced that all the faceted stones are natural and the whole collection include stones from the following countries: Burma, Thailand, Pakistan, Sri Lanka and Tanzania. Results are gathered systematizing bibliographic data and analytical results in order to identify the country of origin of the rubies.
- Sustainability assessment of collagen extraction from fish skins: A comparative life cycle assessment of conventional and NADES-enhanced processesPublication . Miguel P. Batista; Fernández, Naiara; Gaspar, Frédéric B.; Bronze, MR; Duarte, Ana Rita C.; Ortigueira, Joana; Lopes, TiagoABSTRACT: Collagen from blue shark skins offers a promising solution to utilize fishery by-products, reducing waste and improving resource efficiency. This study develops green chemistry-based extraction processes to minimize reliance on traditional chemical methods and lower environmental impacts, prioritizing sustainability and circularity. Two methods for collagen extraction are compared: a conventional alkaline-acid process and an innovative approach using natural deep eutectic solvents (NADES). Process simulations were conducted using SuperPro Designer software for the annual production of 500 kg of pure extracted collagen, followed by life cycle assessment (LCA) using SimaPro software and the Ecoinvent database, applying the Environmental Footprint (EF) method. For 1 kg of pure marine collagen from fish skin residues, defined as the Functional Unit, the conventional approach yielded a single-score impact of 48.1 mPt, while the NADES method achieved 41.5 mPt. Subsystem analysis reveals that, in the conventional method, the extraction and purification stages account for most of the environmental impact (43 % and 45 %, respectively). In contrast, the NADES method attributed 94 % of its total environmental impact to extraction stage, primarily due to NADES component production (citric acid, xylitol). Uncertainty analysis suggests that conclusions regarding impact reduction should be drawn with caution due to the environmental impact variability of considered inputs. Nevertheless, the mathematical model underscores the potential of the NADES method to reduce the environmental impact and promote more sustainable bioprocessing. This work offers valuable insights into the life cycle assessment of large-scale bioprocesses using green chemistry, providing a tool for optimization and environmental impact screening.
- Empowering Citizen Science Through Stakeholder EngagementPublication . Correia, Vítor; Romão, José; Tyrologou, Pavlos; Gomes, Rui Carrilho; Correia, Vítor; Bodó, BalazsABSTRACT: The chapter examines how citizen science projects, particularly in geohazard monitoring, can be strengthened through systematic stakeholder engagement. Using the AGEO project as a case study, with five established Citizen Observatories across Europe, it details how stakeholders were identified, classified, and engaged across political, economic, knowledge and socio-cultural systems. The paper identifies five crucial factors for successful engagement: relevance, accessibility, trust, recognition/incentives, and sustainability. It concludes that citizen science, supported by technological advances and proper stakeholder engagement, can make significant contributions to disaster preparedness and risk reduction, particularly in the context of climate change, by fostering collaboration between experts and communities.
- Is the Rosario Antiform, Iberian Pyrite Belt, a Variscan tectonic window?: a tectono-stratigraphic interpretation based on the geology of the Neves-Corvo mine regionPublication . Oliveira, José TomasABSTRACT: This work suggests a new structural interpretation for the Rosario Antiform, Portuguese Pyrite Belt. This is based on the following successive developments: 1 - Deposition of an upper Visean flysch succession, designated by CMt2, which conformably overlaid the autochthon represented in ascending order by the clastic succession of the Phyllite-Quartzite Formation (PQ) followed by the lower Volcano-Sedimentary Complex (VSC, CVS in the geological map annex) dominated by felsic volcanism and black shale sediments, all of late Devonian age, and the upper VSC composed by shales, volcanoclastic sediments, including cherts and jaspers, and mafic volcanic and igneous rocks of late Tournaisian – late Visean ages; 2 - the reinterpretation of fifteen selected drill hole logs previously carried out by Somincor and LNEG geologists and recovered from the region west of the Neves-Corvo mine proved that below the CMt2 flysch succession the upper VSC is absent in many places and the unit is in direct fault contact with the lower VSC, in a position similar to that recognized in the mine. This abnormal contact is inferred to represent the trace of an extensional fault that locally erased the upper VSC lithologies. A sub-autochthon block composed of remnants of the lower VSC and the overlying CMt2 sediments was then formed above the extensional fault, as discussed below; 3 - a SW directed tangential transport, well documented in the Neves-Corvo mine region, placed a distinct flysch succession (CMt1) and the underlying clastic dominated upper VSC units, all of late Visean age, both forming the allochthon, upon the CMt2 succession. The allochthon is organized as a thinskinned package moving southwestward upon the subautochthon developing a large overthrust. All the package units were folded by a second episode of pervasive regional tectonic compression. 4 – a second tectonic reverse fault at the west limb of the antiform caused the uplifting of the autochthon and the subautochthon which after the regional erosion became a true tectonic window according to this interpretation.
- Copernicus Services and Geohazards Management: Lessons Learnt from Citizens’ ObservatoriesPublication . Montoya-Montes, Isabel; Quental, Lídia; Galindo, Inés; Holohan, Eoghan; Jaud, Marion; Parker, Kieran; Sanchez, Nieves; García Moreno, Inmaculada; Le Dantec, Nicolas; Lemon, Kirstin; Ramalho, Elsa; Machado, Susana; Le Berre, Iwan; Gouveia, Fátima; Pinto, Claúdia; Béjar Pizarro, Marta; Herrera, Gerardo; Gomes, Rui Carrilho; Rodrigues, Domingos; Gonçalves, PedroABSTRACT: With the AGEO Project focused on the assessment and management of geohazards, particular attention was paid to Copernicus EMS, as it supports all phases of the emergency management cycle: preparedness, prevention, disaster risk reduction, emergency response and recovery. The uptake of the Copernicus EMS in the EU Atlantic Region from 2012–2022 is reviewed. Surveys undertaken during the AGEO project highlighting the perception and awareness of stakeholders, as well as their suggestions for improvements or new requirements, are summarised. Uptake of Copernicus and Earth Observation (EO) products in the frame of the citizen observatories on geohazards is also addressed. Finally, strategic recommendations for strengthening the use of Copernicus products and services, and for new Copernicus products for the Atlantic Region are given.
- The old central igneous complexes of Sal, Boa Vista and Maio islands: Implications for 17 Ma of isotopic evolution of the Cape Verde archipelagoPublication . Villaseca, Carlos; Orejana, David; Huertas, Maria J.; Ancochea, Eumenio; Ignacio, Cristina; Mata, João; Caldeira, Rita; Garcia-Rodriguez, Maria; Moreno, Juan A.; Perez-Soba, CeciliaABSTRACT: The central igneous complexes of the easternmost islands (Sal, Boa Vista and Maio) preserve some of the most ancient outcropping rocks of the Cape Verde (CV) archipelago. These Early to Middle Miocene (about 25 to 12 Ma) complexes show marked isotopic differences between mafic rocks from the northern (Sal and Boa Vista) and the southern Maio Island, the latter showing lower 143Nd/144Nd, 206Pb/204Pb, 207Pb/204Pb, and higher 87Sr/86Sr ratios. The main mantle plume composition beneath Cape Verde is here considered to be dominated by the FOZO component. Our data supports previous models suggesting the incorporation to plume components of minor DMM mantle sources in the northern CV island alignment, whereas mixing with the EM1 pole is prevalent on the southern CV islands. These isotopic differences are evident since the early stages of Cape Verde magmatism. The Late Miocene to Holocene time period (7 to 1.7 Ma) is characterized by the irruption of silica-undersaturated and carbonatite magmas with a relatively homogeneous isotopic composition and highly radiogenic Pb signatures (206Pb/204Pb up to 20.6 in carbonatitic rocks and 20.2 in silicate rocks) throughout most of the Cape Verde archipelago. During this transitional stage, the input of this new HIMU mantle component overprinted the previous mixing of the main FOZO plume component with shallow mantle members (DMM, EM1) of minor contribution.
- Clean production of microalgae high-value lipid fraction: Influence of different pretreatments on chemical and cytotoxic profiles of Chlorella vulgaris supercritical extracts and life cycle assessmentPublication . Vladic, Jelena; Radman, Sanja; Jerkovic, Igor; Besu, Irina; Speranza, Lais Galileu; Hala, Ahmad Furqan; Kovacevic, Strahinja; Perreira, Hugo; Gouveia, LuisaABSTRACT: Microalgae have emerged as a promising natural resource rich in bioactive compounds. Health-beneficial properties of microalgae, coupled with advantageous characteristics such as high biomass productivity, adaptability, robustness, and carbon dioxide mitigation, position them as a viable solution for global sustainable food production. This study explored clean and environmentally friendly processes to enhance the recovery of lipid bioactive fractions. Microwave (MW), enzymatic (ENZ), and ultrasound (US) pretreatments were applied to improve environmentally friendly extraction of lipid-based components using supercritical CO2. The effects of these pretreatments on extraction yield, chemical profiles, and cytotoxic properties of Chlorella vulgaris (Cv) and smooth C. vulgaris (sCv) extracts were investigated. Additionally, a Life Cycle Assessment (LCA) was conducted to evaluate environmental impacts. MW pretreatment achieved the highest yield increases, from 2.58 times (Cv) to 3.15 times (sCv). UHPLC-ESI-HRMS analysis revealed shifts in the distribution of pigments and derivatives caused by pretreatments, with ENZ extracts showing the most pronounced changes: pigments increased from 9.24% (control Cv) to 40.92% (Cv) and from 12.52% (control sCv) to 71.12% (sCv). Cv extracts exhibited greater activity against MDA-MB-453 cells, while sCv extracts from US pretreatment demonstrated the strongest effect on HeLa cells. The LCA indicated reduced environmental impacts of the pretreatment-enhanced processes up to 65% compared to the control. A scenario analysis was presented to show further possible impact reduction by recirculating the CO2 solvent and substituting the energy source. These findings provide valuable insights into sustainable and scalable green processes for recovering microalgal bioactive components.
- Hybrid Variable Renewable Power Plants: A Case Study of ROR Hydro ArbitragePublication . Catarino, Isabel; Romão, Inês; Estanqueiro, AnaABSTRACT: Wind and solar energy sources, while sustainable, are inherently variable in their power generation, posing challenges to grid stability due to their non-dispatchable nature. To address this issue, this study explores the synergistic optimization of wind and solar photovoltaic resources to mitigate power output variability, reducing the strain on local grids and lessening the reliance on balancing power in high-penetration renewable energy systems. This critical role of providing stability can be effectively fulfilled by run-of-river hydropower plants, which can complement fluctuations without compromising their standard operational capabilities. In this research, we employ a straightforward energy balance model to analyze the feasibility of a 100 MW virtual hybrid power plant, focusing on the northern region of Portugal as a case study. Leveraging actual consumption and conceptual production data, our investigation identifies a specific run-of-river plant that aligns with the proposed strategy, demonstrating the practical applicability of this approach.
- Evolution of atomically dispersed co-catalysts during solar or UV photocatalysis for efficient and sustained H2 productionPublication . Capelo, Anabela; Fattoruso, Domenico; Valencia-Valero, Laura; Esteves, M. Alexandra; Rangel, Carmen M.; Puga, AlbertoABSTRACT: The evolution of metal/titania photocatalysts during photocatalytic H-2 evolution is herein studied. Samples containing atomically dispersed Pt co-catalysts (single atoms, clusters and sub-nanoparticles) formed after calcination were compared to pre-reduced analogues mostly having metallic nanoparticles (diameters >1 nm) during ethanol photoreforming under either UV-rich irradiation or natural sunlight. Aggregation of ultra-dispersed oxidised platinum entities (Pt delta+) with concomitant reduction into Pt-0 nanoparticles (1-2 nm) was observed after UV irradiation by transmission electron microscopy (TEM), and diffuse reflectance UV-visible (DRUV-vis) and X-ray photoelectron (XPS) spectroscopies. A parallel, albeit slower, evolution trend was evidenced during solar photocatalysis. Conversely, atomically dispersed Cu co-catalyst species did not grow and became in-situ reduced into sub-nanometric Cu-0 under irradiation. Hydrogen production rates were remarkably high during initial stages of UV irradiation, and then declined to a sustained regime (approximate to 50 and 8 mmol g(-1) h(-1) for Pt/TiO2 or Cu/TiO2, respectively, for up to 24 h of irradiation). Steadier solar photoreforming was observed in experiments performed in a compound parabolic collector tubular reactor (approximate to 7.6 and 1.7 mmol g(-1) h(-1) for Pt/TiO2 or Cu/TiO2, respectively). Despite the non-negligible effect of co-catalyst rearrangement on activity rationalised herein, attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy measurements pre- and post-photocatalysis suggest that accumulation of strongly adsorbed degradation intermediates, chiefly acetate, is a major cause for rate decreases. Notwithstanding, this phenomenon did not result in total deactivation, so that sustained hydrogen production upon long-term irradiation was not compromised.