| 1. |
- Agrawal, Munmun, et al.
(författare)
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Global market trends of tantalum and recycling methods from Waste Tantalum Capacitors: A review
- 2021
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Ingår i: Sustainable Materials and Technologies. - : Elsevier BV. - 2214-9937. ; 29
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Forskningsöversikt (refereegranskat)abstract
- The rapid digitalization of the world, technological up-gradation, and shorten life cycle of electronic gadgets leading to the generation of an enormous amount of waste tantalum capacitors (WTCs) rich in tantalum every year. The need of the hour is to develop an effective way to recycle tantalum from these waste scraps considering the scarcity of tantalum, environmental impacts, resource and energy utilization, and lower recycling rates. In this paper, various existing methods of recovery of metallic tantalum from WTCs have been extensively reviewed. Processes have been examined in light of recovery efficiency, purity of the resultant product, process complexity, and limitations. The bottleneck in the recovery of tantalum from WTCs is the presence of tightly covered mold resin over the surface of the tantalum anode. Various researchers have recovered Ta with varying degrees of success. Pyrolysis, followed by chloride metallurgy, has been proven to be an effective technology on account of its high removal rate, resource and energy utilization, and lesser environmental impacts. This article also explores the global scenario of tantalum. Overall this review provides a foundation to understand the potential barrier and various opportunities associated with the recovery of tantalum from WTCs.
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| 2. |
- Ahlgren, Serina, et al.
(författare)
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Review of methodological choices in LCA of biorefinery systems - key issues and recommendations
- 2015
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Ingår i: Biofuels, Bioproducts and Biorefining. - : Wiley. - 1932-1031 .- 1932-104X. ; 9:5, s. 606-619
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Forskningsöversikt (refereegranskat)abstract
- The current trend in biomass conversion technologies is toward more efficient utilization of biomass feedstock in multiproduct biorefineries. Many life-cycle assessment (LCA) studies of biorefinery systems have been performed but differ in how they use the LCA methodology. Based on a review of existing LCA standards and guidelines, this paper provides recommendations on how to handle key methodological issues when performing LCA studies of biorefinery systems. Six key issues were identified: (i) goal definition, (ii) functional unit, (iii) allocation of biorefinery outputs, (iv) allocation of biomass feedstock, (v) land use, and (vi) biogenic carbon and timing of emissions. Many of the standards and guidelines reviewed here provide only general methodological recommendations. Some make more specific methodological recommendations, but these often differ between standards. In this paper we present some clarifications (e.g. examples of research questions and suitable functional units) and methodological recommendations (e.g. on allocation).
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| 3. |
- Calvin, Katherine, et al.
(författare)
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Bioenergy for climate change mitigation: Scale and sustainability
- 2021
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Ingår i: GCB Bioenergy. - : Wiley. - 1757-1707 .- 1757-1693. ; 13:9, s. 1346-1371
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Forskningsöversikt (refereegranskat)abstract
- Many global climate change mitigation pathways presented in IPCC assessment reports rely heavily on the deployment of bioenergy, often used in conjunction with carbon capture and storage. We review the literature on bioenergy use for climate change mitigation, including studies that use top-down integrated assessment models or bottom-up modelling, and studies that do not rely on modelling. We summarize the state of knowledge concerning potential co-benefits and adverse side effects of bioenergy systems and discuss limitations of modelling studies used to analyse consequences of bioenergy expansion. The implications of bioenergy supply on mitigation and other sustainability criteria are context dependent and influenced by feedstock, management regime, climatic region, scale of deployment and how bioenergy alters energy systems and land use. Depending on previous land use, widespread deployment of monoculture plantations may contribute to mitigation but can cause negative impacts across a range of other sustainability criteria. Strategic integration of new biomass supply systems into existing agriculture and forest landscapes may result in less mitigation but can contribute positively to other sustainability objectives. There is considerable variation in evaluations of how sustainability challenges evolve as the scale of bioenergy deployment increases, due to limitations of existing models, and uncertainty over the future context with respect to the many variables that influence alternative uses of biomass and land. Integrative policies, coordinated institutions and improved governance mechanisms to enhance co-benefits and minimize adverse side effects can reduce the risks of large-scale deployment of bioenergy. Further, conservation and efficiency measures for energy, land and biomass can support greater flexibility in achieving climate change mitigation and adaptation.
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| 4. |
- Gebremeskel, Dawit, et al.
(författare)
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Long-term electricity supply modelling in the context of developing countries: The OSeMOSYS-LEAP soft-linking approach for Ethiopia
- 2023
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Ingår i: Energy Strategy Reviews. - : Elsevier BV. - 2211-467X. ; 45
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Forskningsöversikt (refereegranskat)abstract
- Long-term power supply modelling is particularly important for developing countries in providing sustainable solutions to electricity problems. This study presents the first detailed and complete model of the Ethiopian electricity system while considering the unique features (dominance of traditional energy, informal economy, urban-rural divide, low electrification, supply shortage, etc.) and context of developing countries that is developed by soft-linking the OSeMOSYS (Open-Source energy Modelling System) and LEAP (Long-range Energy Alternatives Planning System) modelling frameworks. Better system representation and design of plausible scenarios that explore the potential pathways of the future power supply and demand evolution until 2050 is done by performing sensitivity analysis. Sector wise and technological representation of supply and end-uses at a disaggregated level, assessment of centralized grid-based means and decentralized off-grid methods for improving electricity access are the main methodological contributions. Five policy scenarios are employed to explore different possible futures and balance the long-term electricity needs and resources. The improved efficiency scenario reduces the installed capacity by 9 GW which translates into approximately 11% total discounted cost saving (USD $ 4 billion). This economic benefit has made the efficiency scenario the most desirable compared to the other scenarios. Attributed to lower investment costs and abundant resource availability, the results show that renewable technologies are more competitive and favourable.
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| 5. |
- Diamond, Miriam, et al.
(författare)
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Exploring the planetary boundary for chemical pollution
- 2015
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 78, s. 8-15
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Forskningsöversikt (refereegranskat)abstract
- Rockström et al. (2009a, 2009b) have warned that humanity must reduce anthropogenic impacts defined by nine planetary boundaries if “unacceptable global change” is to be avoided. Chemical pollution was identified as one of those boundaries for which continued impacts could erode the resilience of ecosystems and humanity. The central concept of the planetary boundary (or boundaries) for chemical pollution (PBCP or PBCPs) is that the Earth has a finite assimilative capacity for chemical pollution, which includes persistent, as well as readily degradable chemicals released at local to regional scales, which in aggregate threaten ecosystem and human viability. The PBCP allows humanity to explicitly address the increasingly global aspects of chemical pollution throughout a chemical's life cycle and the need for a global response of internationally coordinated control measures. We submit that sufficient evidence shows stresses on ecosystem and human health at local to global scales, suggesting that conditions are transgressing the safe operating space delimited by a PBCP. As such, current local to global pollution control measures are insufficient. However, while the PBCP is an important conceptual step forward, at this point single or multiple PBCPs are challenging to operationalize due to the extremely large number of commercial chemicals or mixtures of chemicals that cause myriad adverse effects to innumerable species and ecosystems, and the complex linkages between emissions, environmental concentrations, exposures and adverse effects. As well, the normative nature of a PBCP presents challenges of negotiating pollution limits amongst societal groups with differing viewpoints. Thus, a combination of approaches is recommended as follows: develop indicators of chemical pollution, for both control and response variables, that will aid in quantifying a PBCP(s) and gauging progress towards reducing chemical pollution; develop new technologies and technical and social approaches to mitigate global chemical pollution that emphasize a preventative approach; coordinate pollution control and sustainability efforts; and facilitate implementation of multiple (and potentially decentralized) control efforts involving scientists, civil society, government, non-governmental organizations and international bodies.
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| 6. |
- Gentil, Emmanuel C., et al.
(författare)
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Models for waste life cycle assessment : Review of technical assumptions
- 2010
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 30:12, s. 2636-2648
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Forskningsöversikt (refereegranskat)abstract
- A number of waste life cycle assessment (LCA) models have been gradually developed since the early 1990s, in a number of countries, usually independently from each other. Large discrepancies in results have been observed among different waste LCA models, although it has also been shown that results from different LCA studies can be consistent. This paper is an attempt to identify, review and analyse methodologies and technical assumptions used in various parts of selected waste LCA models. Several criteria were identified, which could have significant impacts on the results, such as the functional unit, system boundaries, waste composition and energy modelling. The modelling assumptions of waste management processes, ranging from collection, transportation, intermediate facilities, recycling, thermal treatment, biological treatment, and landfilling, are obviously critical when comparing waste LCA models. This review infers that some of the differences in waste LCA models are inherent to the time they were developed. It is expected that models developed later, benefit from past modelling assumptions and knowledge and issues. Models developed in different countries furthermore rely on geographic specificities that have an impact on the results of waste LCA models. The review concludes that more effort should be employed to harmonise and validate non-geographic assumptions to strengthen waste LCA modelling.
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| 7. |
- Afif, A., et al.
(författare)
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Advanced materials and technologies for hybrid supercapacitors for energy storage – A review
- 2019
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Ingår i: Journal of Energy Storage. - : Elsevier BV. - 2352-152X. ; 25:October 2019
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Forskningsöversikt (refereegranskat)abstract
- Supercapacitors have become the most significant energy conversion and storage system in recent renewable and sustainable nanotechnology. Due to its large energy capacity and supply with relatively short time and longer lifetime, supercapacitors breakthrough in advance energy applications. This review presents a comparative study of different materials, working principles, analysis, applications, advantages and disadvantages of various technologies available for supercapacitors. The aim of this article is to discuss the possibility of hybrid supercapacitor for the next generation of energy technology. The development of composite materials containing a wide range of active constituents (e.g., graphene, activated carbon, transition metals, metal oxides, perovskites and conducting polymers) by in-situ hybridization and ex-situ recombination is also discussed. This review consecrated largely the contribution of combining all materials (electrode and electrolyte) and their synthesis process and electrochemical performance. Enduringly, the potential issues and the perspectives for future research based on hybrid supercapacitors in energy applications are also presented.
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| 8. |
- Arvidsson, Rickard, 1984, et al.
(författare)
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Environmental Assessment of Emerging Technologies: Recommendations for Prospective LCA
- 2018
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Ingår i: Journal of Industrial Ecology. - : Wiley. - 1530-9290 .- 1088-1980. ; 22:6, s. 1286-1294
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Forskningsöversikt (refereegranskat)abstract
- The challenge of assessing emerging technologies with life cycle assessment (LCA) has been increasingly discussed in the LCA field. In this article, we propose a definition of prospective LCA: An LCA is prospective when the (emerging) technology studied is in an early phase of development (e.g., small-scale production), but the technology is modeled at a future, more-developed phase (e.g., large-scale production). Methodological choices in prospective LCA must be adapted to reflect this goal of assessing environmental impacts of emerging technologies, which deviates from the typical goals of conventional LCA studies. The aim of the article is to provide a number of recommendations for how to conduct such prospective assessments in a relevant manner. The recommendations are based on a detailed review of selected prospective LCA case studies, mainly from the areas of nanomaterials, biomaterials, and energy technologies. We find that it is important to include technology alternatives that are relevant for the future in prospective LCA studies. Predictive scenarios and scenario ranges are two general approaches to prospective inventory modeling of both foreground and background systems. Many different data sources are available for prospective modeling of the foreground system: scientific articles; patents; expert interviews; unpublished experimental data; and process modeling. However, we caution against temporal mismatches between foreground and background systems, and recommend that foreground and background system impacts be reported separately in order to increase the usefulness of the results in other prospective studies.
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| 9. |
- Baran, Tomasz, et al.
(författare)
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Copper oxide-based photocatalysts and photocathodes: Fundamentals and recent advances
- 2021
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Ingår i: Molecules. - : MDPI AG. - 1420-3049 .- 1420-3049 .- 1431-5157. ; 26:23
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Forskningsöversikt (refereegranskat)abstract
- This work aims at reviewing the most impactful results obtained on the development of Cu-based photocathodes. The need of a sustainable exploitation of renewable energy sources and the parallel request of reducing pollutant emissions in airborne streams and in waters call for new technologies based on the use of efficient, abundant, low-toxicity and low-cost materials. Photoelectrochemical devices that adopts abundant element-based photoelectrodes might respond to these requests being an enabling technology for the direct use of sunlight to the production of energy fuels form water electrolysis (H2) and CO2 reduction (to alcohols, light hydrocarbons), as well as for the degradation of pollutants. This review analyses the physical chemical properties of Cu2O (and CuO) and the possible strategies to tune them (doping, lattice strain). Combining Cu with other elements in multinary oxides or in composite photoelectrodes is also discussed in detail. Finally, a short overview on the possible applications of these materials is presented.
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| 10. |
- Beretta, Davide, et al.
(författare)
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Thermoelectrics: From history, a window to the future
- 2019
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Ingår i: Materials Science and Engineering: R: Reports. - : Elsevier BV. - 0927-796X. ; 138
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Forskningsöversikt (refereegranskat)abstract
- Thermoelectricity offers a sustainable path to recover and convert waste heat into readily available electric energy, and has been studied for more than two centuries. From the controversy between Galvani and Volta on the Animal Electricity, dating back to the end of the XVIII century and anticipating Seebeck's observations, the understanding of the physical mechanisms evolved along with the development of the technology. In the XIX century Ørsted clarified some of the earliest observations of the thermoelectric phenomenon and proposed the first thermoelectric pile, while it was only after the studies on thermodynamics by Thomson, and Rayleigh's suggestion to exploit the Seebeck effect for power generation, that a diverse set of thermoelectric generators was developed. From such pioneering endeavors, technology evolved from massive, and sometimes unreliable, thermopiles to very reliable devices for sophisticated niche applications in the XX century, when Radioisotope Thermoelectric Generators for space missions and nuclear batteries for cardiac pacemakers were introduced. While some of the materials adopted to realize the first thermoelectric generators are still investigated nowadays, novel concepts and improved understanding of materials growth, processing, and characterization developed during the last 30 years have provided new avenues for the enhancement of the thermoelectric conversion efficiency, for example through nanostructuration, and favored the development of new classes of thermoelectric materials. With increasing demand for sustainable energy conversion technologies, the latter aspect has become crucial for developing thermoelectrics based on abundant and non-toxic materials, which can be processed at economically viable scales, tailored for different ranges of temperature. This includes high temperature applications where a substantial amount of waste energy can be retrieved, as well as room temperature applications where small and local temperature differences offer the possibility of energy scavenging, as in micro harvesters meant for distributed electronics such as sensor networks. While large scale applications have yet to make it to the market, the richness of available and emerging thermoelectric technologies presents a scenario where thermoelectrics is poised to contribute to a future of sustainable future energy harvesting and management. This work reviews the broad field of thermoelectrics. Progress in thermoelectrics and milestones that led to the current state-of-the-art are presented by adopting an historical footprint. The review begins with an historical excursus on the major steps in the history of thermoelectrics, from the very early discovery to present technology. A panel on the theory of thermoelectric transport in the solid state reviews the transport theory in complex crystal structures and nanostructured materials. Then, the most promising thermoelectric material classes are discussed one by one in dedicated sections and subsections, carefully highlighting the technological solutions on materials growth that have represented a turning point in the research on thermoelectrics. Finally, perspectives and the future of the technology are discussed in the framework of sustainability and environmental compatibility. © 2018 Elsevier B.V.
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