4161 research outputs found
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Intercomparison of opto-thermal spectral measurements for concentrating solar thermal receiver materials from room temperature up to 800 °C
Get PDFABSTRACT: An intercomparison of opto-thermal spectral measurements has been performed for some relevant receiver materials in concentrating solar thermal applications, from room temperature up to 800 degrees C. Five European laboratories performed spectral measurements at room temperature, while two laboratories performed infrared spectral measurements at operating temperature up to 800 degrees C. Relevant materials include Haynes 230 (oxidized, Pyromark 2500 and industrial black coating) and silicon carbide. Two key figures of merit were analyzed: i) solar absorptance alpha sol at room temperature, over the spectral range [0.3 - 2.5] mu m, ii) thermal emittance epsilon th(T), over the common spectral range [2-14] mu m, derived from spectral measurements performed from room temperature up to 800 degrees C. Oxidized H230 reached an alpha sol value of 90.9 +/- 1.0%. Pyromark 2500 reached an alpha sol value of 96.3 +/- 0.5%, while the industrial black coating achieved an alpha sol value of 97.0 +/- 0.4%. Silicon carbide reached an alpha sol value of 93.5 +/- 1.1%. Low standard deviations in alpha sol indicate reproducible measurements at room temperature. For oxidized H230, the epsilon th,calc(T) value varied from 55% at room temperature up to 81% at 800 degrees C. For Pyromark 2500 and the industrial black coating, epsilon th,calc(T) fluctuated between 90% and 95%, with a weak temperature dependence. For silicon carbide, epsilon th,calc(T) varied from 70% at room temperature up to 86% at 800 degrees C. The typical standard deviation among participating laboratories is about 3%. epsilon th,meas(T) values derived from spectral measurements at operating temperature were consistent within a few percentage points in comparison to epsilon th,calc(T) values derived from spectral measurements at room temperature.info:eu-repo/semantics/publishedVersio
Unlocking the Secondary Critical Raw Material Potential of Historical Mine Sites, Lousal Mine, Southern Portugal
Get PDFABSTRACT: A steady supply of mineral raw materials is vital for the transition to a low-carbon, circular economy. The number of active mines in Europe has severely declined over the last century and half, giving rise to many abandoned mining waste sites and corresponding geological heritage. Also, the rise in minerals demand for large-scale deployment of renewable energy requires the continued and steady availability of key minerals. The supply risk associated with unpredicted geopolitical events needs to be eliminated/mitigated. Historical mine waste sites are the answer but evaluating mine waste is a lengthy and costly exercise. The study, undertaken in the Lousal Mine, used small unmanned aerial systems (sUASs) to model and determine mine waste volumes by generating orthomosaic maps with quick, inexpensive, and reliable results. Calculated mine waste volumes between 308,478 m3 and 322,455 m3 were obtained. XRD and p-XRF techniques determined the mineralogy and chemistry of waste, which varied from mineralization and host rocks with hydrothermal alteration and numerous neogenic sulphates (mostly gypsum, rhomboclase, ferricopiapite, coquimbite, and jarosite) related with supergene processes and weathering. The study shows the viability of using these sUASs to successfully model historical mine waste sites in an initial phase and for future monitoring programs.info:eu-repo/semantics/publishedVersio
Simulation and study of the milling parameters on CuFeTaTiW multicomponent alloy
Get PDFABSTRACT: The CuFeTaTiW multicomponent alloy has been devised as an interlayer thermal barrier in nuclear fusion re-actors. In order to predict the phase constitution of this alloy, two different lines of work were performed: (a) simulation using Molecular dynamics and Monte Carlo and (b) study of the influence of mechanical alloying parameters on the structures formed. The simulation results show that the most stable structure is achieved starting from a bcc type-structure and using Monte Carlo simulation. In fact, in these conditions the separation into two bcc phases Fe-Ta-W and Cu-Ti is predicted at room temperature. However, the experimental preparation of the materials with mechanical alloying revealed that from 2 h of milling a single bcc phase is formed. The structure of the milled powder was not much influenced by the amount of the process control agent and the by the size of the W starting particles, but generally there was formation of Ta2H from the reaction between the powders and the process control agent.info:eu-repo/semantics/publishedVersio
Demand-side strategies key for mitigating material impacts of energy transitions
No full textABSTRACT: As fossil fuels are phased out in favour of renewable energy, electric cars and other low-carbon technologies, the future clean energy system is likely to require less overall mining than the current fossil-fuelled system. However, material extraction and waste flows, new infrastructure development, land-use change, and the provision of new types of goods and services associated with decarbonization will produce social and environmental pressures at localized to regional scales. Demand-side solutions can achieve the important outcome of reducing both the scale of the climate challenge and material resource requirements. Interdisciplinary systems modelling and analysis are needed to identify opportunities and trade-offs for demand-led mitigation strategies that explicitly consider planetary boundaries associated with Earth's material resources. The material-intensive transition to low-carbon energy will impose environmental and social burdens on local and regional communities. Demand-side strategies can help to achieve higher well-being at lower levels of energy or material use, and an interdisciplinary approach in future research is essential.info:eu-repo/semantics/publishedVersio
Pressurized pyrolysis of mattress residue: An alternative to landfill management
Get PDFABSTRACT: Mattresses are a difficult waste to manage in landfills due to their large volume and low density. Pyrolysis treatment could reduce its volume while producing fuel or products valuable for the chemical industry. Pressurized pyrolysis at 400, 450, and 500 degrees C is carried out in a lab-scale autoclave at initial pressures 4.2, 8.4, and 16.8 bar. Product gas yield increases slightly along with elevated pressure as well as temperature. However, beyond 8.4 bar the initial pressure makes no discernible differences. CO and CO2 are the major gas species followed by CH4. CO contributes the most to the product gas energy content followed by C-3 species, C2H6, and H-2. Calculated energy content (heating value) is between 2 and 15 MJ.Nm(-3). In terms of product gas energy content, low pressure pyrolysis is favorable over high pressure pyrolysis. According to integration areas of chromatographic measurements the liquid phase contains up to 25 % of N-compounds, with benzonitrile being the most abundant, followed by toluene, o-xylene, and ethylbenzene. The solid char maintains constant properties across operating conditions, with carbon and energy contents of approximately 75 wt% and 30 MJ.kg(-1), respectively.info:eu-repo/semantics/publishedVersio
Late Famennian (latest Strunian) palynomorph assemblages and their role in the Neves Formation depositional environment -The Neves-Corvo mine case study (Iberian Pyrite Belt, Portugal)
No full textABSTRACT: This research examines palynomorph assemblages preserved in sediments of the Iberian Pyrite Belt (IPB) that host the Neves-Corvo massive sulfide deposit and its importance for mineral exploration. The sediments belong to the Neves Formation, characterized by black shales and minor occurrences of siltstones and cherts, indicative of reduced environmental conditions, favorable to sulfide deposition in a hydrothermal context dominated by submarine felsic volcanism and graben structures. Analysis was performed in barren drill holes (e.g., Monte Novo), as opposed to productive sectors with massive sulfide mineralization and/or stockwork vein networks (e.g., Lombador, Corvo and Semblana deposits) and favorable sectors like Algar & eacute;. The recovered palynological assemblages are assigned to the LN Miospore Biozone, indicating a Late Famennian (latest Strunian) age. Several characteristic species of this age are identified, such as Retispora lepidophyta and Verrucosisporites nitidus in close association with Densosporites spitbergensis, Dictyotriletes fimbriatus, Retusotriletes cf. incohatus, Retusotriletes crassus, Vallatisporites spp. (including V. pusillites, and V. verrucosus). ) . Despite some palynomorphs showing signs of breakage, folding, and indistinctness, no significant preservation or diversity differences were noted between barren and mineralized areas. The high abundance of marine phytoplankton in all studied black shales indicates ecologically stressed setting, dominated by dysoxic to anoxic conditions in a distal marine setting with active felsic volcanism and hydrothermal mineralizing events during Late Famennian time. This geologic context correlates with other IPB deposits and the global latest Devonian anoxic Hangenberg event.info:eu-repo/semantics/publishedVersio
Resources recovery from domestic wastewater by a combined process: anaerobic digestion and membrane photobioreactor
Get PDFABSTRACT: Anaerobic and membrane technologies are a promising combination to decrease the energy consumption associated with wastewater treatment, allowing the recovery of resources: organic matter as biomethane, nutrient assimilation by microalgae and reclaimed water. In this study, domestic wastewater was treated using a combination of an upflow anaerobic sludge blanket sludge reactor (UASB) and a membrane photobioreactor (MPBR). The outdoor facilities were operated continuously for three months under unfavourable environmental conditions such as lack of temperature control, winter season with lower solar irradiation and lower daylight hours which was a challenge for the present work, not previously described. The energetic valorisation of the organic matter present in the wastewater by biomethane produced in the UASB would contribute to reducing overall facilities’ energy requirements. The ultrafiltration (UF) membrane facilitated the harvesting of biomass, operating at 10 L·h−1·m−2 during the experimental period. Although the main contribution to fouling was irreversible, chemical cleanings were not necessary due to effective fouling control, which prevented the final TMP from exceeding 25 kPa. In addition, microalgae-bacterial consortium developed without prior inoculation were harvested from the MPBR using membrane assistance. The obtained biomass was also successfully tested as a biostimulant for corn germination/growth, as well as a biopesticide against Rhizoctonia solani and Fusarium oxysporum.info:eu-repo/semantics/publishedVersio
The H2Excellence Project: Fuel Cells and Green Hydrogen Centers of Vocational Excellence towards affordable, secure, and sustainable energy for Europe [Resumo]
Get PDFABSTRACT: The demand for green hydrogen (H2) and related technologies is expected to increase in the coming years mainly framed by drivers such as climate change and energy security of supply amid the European and global energy crises. REpowerEU Plan called for an intensification of hydrogen delivery targets, that will bring large-scale adoption of hydrogen production and applications in various sectors, stressing the need for a skilled workforce in the emergent hydrogen markets. To that end, the Erasmus+ European H2Excellence transnational project[2] has gathered 24 partners across the EU, to establish a Platform of Vocational Excellence in the field of fuel cells and green hydrogen technologies, with an educational and training offer that will tackle identified skill gaps and implement life-long learning opportunities. The project aims to become a benchmark in training and knowledge transfer, contributing to the integration of quality employment into green hydrogen local innovative systems approaching the entire hydrogen value chain.N/
Tutorial and webinar edited material (D6.2.2) : Deliverable D6.3
No full textProject TradeRES - New Markets Design & Models for 100% Renewable Power SystemsN/