3,182 research outputs found

    Highlighting the need to embed circular economy in low carbon infrastructure decommissioning: The case of offshore wind

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    Development and deployment of low carbon infrastructure (LCI) is essential in a period of accelerated climate change. The deployment of LCI is, however, not taking place with any obvious long term or joined up thinking in respect of life-cycle material extraction, usage and recovery across technologies or otherwise. This proposition is demonstrated through empirical quantification of selected infrastructure and a review of decommissioning plans, as exemplified by offshore wind in the United Kingdom. There is wide acknowledgement that offshore wind and other LCI are dependant on the production and use of many composite and critical materials that can and regularly do inflict high impacts on the environment and society during their extraction and manufacturing. To optimise resource use from a whole system perspective, it is thus essential that the components of LCI and the materials they share and are comprised of, are designed with a circular economy in mind. As such, LCI must be designed for durability, reuse and remanufacturing, rather than committing them to sub-optimal waste management and energy recovery pathways. Beyond a promise to remove installed components, end-of-life decommissioning plans do not however provide any insight into a given operators’ awareness of the nuances of their proposed material management methods or indeed current or future management capacities. Decommissioning plans for offshore wind are at best formulaic and at worst perfunctory and provide no value to the growing movement toward a circular economy. At this time, millions of tonnes of composites, precious and rare earth materials are being extracted, processed and deployed in infrastructure with nothing in place that suggests that these materials can be sustainably recovered, managed and returned to productive use at the potential scales required to meet accelerating LCI deployment. Academic and industry literature, or lack thereof, suggest that this statement is largely reflected throughout LCI deployment and not just within the deployment of offshore wind in the UK

    Sustainable Palm Oil Supply Chains: Complexity, Custody and Contention

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    Demand for palm oil is strong. It and other products of the oil palm are pervasive in modern society. The sustainability of oil palm cultivation is, however, contested. Different interpretations of sustainability have created conflict at the point of production with perceived Western values conflicting with the perceived needs of palm oil producing countries. This paper contributes to the sustainable supply chain management literature by discussing how stakeholders, with differing objectives, influence behaviour along complex palm oil supply chains. Based on field observation and interviews with these key stakeholders, the paper considers economic, ethical and environmental aspects emerging from efforts to create sustainable palm oil supply chains. In particular, the paper looks at efforts to achieve traceability of supplies and the impacts of such efforts. Insights from this research will help raise awareness of the supply chain dynamics of the palm oil industry, the conflicting challenges faced by downstream buyers and upstream producers, and how well-meaning efforts to support socio-economic development potentially harms efforts to drive sustainable production of oil palm

    Mapping the production-consumption gap of an urban food system: an empirical case study of food security and resilience

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    Urban food systems are complex and increasingly recognised as not being sustainable, equitable or resilient. Though globalisation and lengthening of agrifood supply chains has brought many benefits, such as year-long availability of fresh produce and modernisation opportunities for some developing regions, they have increased reliance on food imports and reduced the food and nutrition resilience of many cities. This premise has been widely witnessed following recent financial, climatic and pandemic driven disruptions to food supplies. A greater understanding is thus needed of the lived reality of a modern city’s ability to sustainably and equitably feed itself in a crisis situation or otherwise. In a changing world, such knowledge is valuable on a variety of strategic planning levels. Employing publically available data, the scale of food security and resilience, and options for their improvement, are holistically assessed through a case study spatial analysis of the urban food system of the city of Leeds in the United Kingdom. The case study found that the Leeds city region is home to a significant and diverse food production and provision system, but it is not food secure in terms of providing sufficient energy or macronutrients, or functioning in an equitable manner for all of its residents. Options for improving the performance of the system, including urban farming and industrial symbiosis, were found to be nuanced and would only be effective alongside a range of complimentary interventions as well as high levels of investment, multi-sector cooperation and strong governance. Though food system evolution and development are grounded in local context, the methods, general findings and circular economy focussed recommendations emanating from the case study, are widely applicable

    Iron chelation therapy in the myelodysplastic syndromes and aplastic anemia: a review of experience in South Korea

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    Emerging clinical data indicate that transfusion-dependent patients with bone marrow-failure syndromes (BMFS) are at risk of the consequences of iron overload, including progressive damage to hepatic, endocrine, and cardiac organs. Despite the availability of deferoxamine (DFO) in Korea since 1998, data from patients with myelodysplastic syndromes, aplastic anemia, and other BMFS show significant iron overload and damage to the heart and liver. The recent introduction of deferasirox, a once-daily, oral iron chelator, may improve the availability of iron chelation therapy to iron-overloaded patients, and improve compliance in patients who may otherwise find adherence to the DFO regimen difficult

    Parameterized Directed kk-Chinese Postman Problem and kk Arc-Disjoint Cycles Problem on Euler Digraphs

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    In the Directed kk-Chinese Postman Problem (kk-DCPP), we are given a connected weighted digraph GG and asked to find kk non-empty closed directed walks covering all arcs of GG such that the total weight of the walks is minimum. Gutin, Muciaccia and Yeo (Theor. Comput. Sci. 513 (2013) 124--128) asked for the parameterized complexity of kk-DCPP when kk is the parameter. We prove that the kk-DCPP is fixed-parameter tractable. We also consider a related problem of finding kk arc-disjoint directed cycles in an Euler digraph, parameterized by kk. Slivkins (ESA 2003) showed that this problem is W[1]-hard for general digraphs. Generalizing another result by Slivkins, we prove that the problem is fixed-parameter tractable for Euler digraphs. The corresponding problem on vertex-disjoint cycles in Euler digraphs remains W[1]-hard even for Euler digraphs

    Preadaptation of pandemic GII.4 noroviruses in unsampled virus reservoirs years before emergence

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    The control of re-occurring pandemic pathogens requires understanding the origins of new pandemic variants and the factors that drive their global spread. This is especially important for GII.4 norovirus, where vaccines under development offer promise to prevent hundreds of millions of annual gastroenteritis cases. Previous studies have hypothesized that new GII.4 pandemic viruses arise when previously circulating pandemic or pre-pandemic variants undergo substitutions in antigenic regions that enable evasion of host population immunity, as described by conventional models of antigenic drift. In contrast, we show here that the acquisition of new genetic and antigenic characteristics cannot be the proximal driver of new pandemics. Pandemic GII.4 viruses diversify and spread over wide geographical areas over several years prior to simultaneous pandemic emergence of multiple lineages, indicating that the necessary sequence changes must have occurred before diversification, years prior to pandemic emergence. We confirm this result through serological assays of reconstructed ancestral virus capsids, demonstrating that by 2003, the ancestral 2012 pandemic strain had already acquired the antigenic characteristics that allowed it to evade prevailing population immunity against the previous 2009 pandemic variant. These results provide strong evidence that viral genetic changes are necessary but not sufficient for GII.4 pandemic spread. Instead, we suggest that it is changes in host population immunity that enable pandemic spread of an antigenically preadapted GII.4 variant. These results indicate that predicting future GII.4 pandemic variants will require surveillance of currently unsampled reservoir populations. Furthermore, a broadly acting GII.4 vaccine will be critical to prevent future pandemics

    Can spacetime curvature induced corrections to Lamb shift be observable?

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    The Lamb shift results from the coupling of an atom to vacuum fluctuations of quantum fields, so corrections are expected to arise when the spacetime is curved since the vacuum fluctuations are modified by the presence of spacetime curvature. Here, we calculate the curvature-induced correction to the Lamb shift outside a spherically symmetric object and demonstrate that this correction can be remarkably significant outside a compact massive astrophysical body. For instance, for a neutron star or a stellar mass black hole, the correction is \sim 25% at a radial distance of 4GM/c24GM/c^2, \sim 16% at 10GM/c210GM/c^2 and as large as \sim 1.6% even at 100GM/c2100GM/c^2, where MM is the mass of the object, GG the Newtonian constant, and cc the speed of light. In principle, we can look at the spectra from a distant compact super-massive body to find such corrections. Therefore, our results suggest a possible way of detecting fundamental quantum effects in astronomical observations.Comment: 13 pages, 3 figures, slight title change, clarifications and more discussions added, version to be published in JHE

    Ballistic nanofriction

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    Sliding parts in nanosystems such as Nano ElectroMechanical Systems (NEMS) and nanomotors, increasingly involve large speeds, and rotations as well as translations of the moving surfaces; yet, the physics of high speed nanoscale friction is so far unexplored. Here, by simulating the motion of drifting and of kicked Au clusters on graphite - a workhorse system of experimental relevance -- we demonstrate and characterize a novel "ballistic" friction regime at high speed, separate from drift at low speed. The temperature dependence of the cluster slip distance and time, measuring friction, is opposite in these two regimes, consistent with theory. Crucial to both regimes is the interplay of rotations and translations, shown to be correlated in slow drift but anticorrelated in fast sliding. Despite these differences, we find the velocity dependence of ballistic friction to be, like drift, viscous

    A novel knowledge repository to support industrial symbiosis

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    The development of tools and methods supporting the identification of Industrial Symbiosis opportunities is of utmost importance to unlock its full potential. Knowledge repositories have proven to be powerful tools in this sense, but often fail mainly due to poor contextualization of information and lack of general applicability (out of the boundaries of specific areas or projects). In this work, a novel approach to the design of knowledge repositories for Industrial Symbiosis is presented, based on the inclusion and categorization of tacit knowledge as well as on the combination of mimicking and input-output matching approaches. The results of a first usability test of the proposed tool are also illustrated
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