1,429 research outputs found

    Product-service Systems and Sustainability: Opportunities for Sustainable Solutions

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    Given that the concept of PSS is beginning to 'catch on' and gain attention, it is time for UNEP to contribute to, and influence the progress of PSS, to ensure that in concept and application it incorporates the idea of sustainability. In this context its potential is not generally understood by the public and private sectors or civil society. This booklet is intended to contribute to the dissemination and the discussion of the PSS concept as a promising approach to sustainability. The ultimate goal must be to achieve Sustainable Product-Service Systems. This UNEP publication is targeted at industry and government, academia and civil society to explain PSS – their potential benefits and limitations – in the sustainability context – using real company examples. To prepare this booklet, UNEP has drawn on the knowledge and experience of PSS experts to flesh out the concept of a sustainable PSS, to collect case studies of PSS in practice, to begin to document both its benefits and the hurdles which need to be overcome in its application, and to suggest ways forward in its development

    Stratospheric climate and variability from a general circulation model and observations. Part II: Results for March-May, June-August and September-November.

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    The climate and natural variability of the large-scale stratospheric circulation simulated by a newly developed general circulation model are evaluated against available global observations. The simulation consisted of a 30-year annual cycle integration performed with a comprehensive model of the troposphere and stratosphere. The observations consisted of a 15-year dataset from global operational analyses of the troposphere and stratosphere. The model evaluation concentrates on the simulation of the evolution of the extratropical stratospheric circulation in both hemispheres. The December-February climatology of the observed zonal mean winter circulation is found to be reasonably well captured by the model, although in the Northern Hemisphere upper stratosphere the simulated westerly winds are systematically stronger and a cold bias is apparent in the polar stratosphere. This Northern Hemisphere stratospheric cold bias virtually disappears during spring (March-May), consistent with a realistic simulation of the spring weakening of the mean westerly winds in the model. A considerable amount of monthly interannual variability is also found in the simulation in the Northern Hemisphere in late winter and early spring. The simulated interannual variability is predominantly caused by polar warmings of the stratosphere, in agreement with observations. The breakdown of the Northern Hemisphere stratospheric polar vortex appears therefore to occur in a realistic way in the model. However, in early winter the model severely underestimates the interannual variability, especially in the upper troposphere. The Southern Hemisphere winter (June-August) zonal mean temperature is systematically colder in the model, and the simulated winds are somewhat too strong in the upper stratosphere. Contrary to the results for the Northern Hemisphere spring, this model cold bias worsens during the Southern Hemisphere spring (September-November). Significant discrepancies between the model results and the observations are therefore found during the breakdown of the Southern Hemisphere polar vortex. For instance, the simulated Southern Hemisphere stratospheric westerly jet continuously decreases in intensity more or less in situ from June to November, while the observed stratospheric jet moves downward and poleward

    Policy constellations as ecosystems of design actions: Exploring three cases of social innovation policies in Italy

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    The article considers social innovation in an eco-systemic perspective, focusing on policies able to foster it and discussing design’s role within them in terms of professional skills and a widespread capability among all social actors involved. To be expressions of an innovative governance, social innovation policies must themselves be innovative and form policy constellations: clusters of initiatives able to interact positively with the socio-technical system on which they seek to impact. The article is specifically devoted to illustrating the notion of policy constellation, discussing three social innovation policies in Italy: ‘Bologna Regulation’, ‘Milan Smart City’ and ‘Bollenti Spiriti’ in Apulia. All three case studies refer to project strategies that lead to the creation of ecosystems of independent (but mutually synergic) initiatives. Until now, expert design has had a sometimes significant, but generally marginal, presence in this field (mostly as strategic design and, to a lesser extent, as service and communication design). This article suggests that this could and should increase in the future. The authors conclude by posing a new question: what holds together the constituent projects in a social innovation policy? A possible hypothesis is that this something is a cultural frame: a vision of the world shared by all the actors involved

    The effect of varying the source spectrum of a gravity wave parameterization in a middle atmosphere general circulation model

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    Climate simulations of the middle atmosphere circulation with general circulation models are now starting to include parameterizations of the momentum flux deposition due to unresolved gravity wave spectra. A current uncertainty in the application of such parameterizations is the specification of the imposed gravity wave spectrum. The aim of this work is to quantify the effect of varying within a realistic range the source spectrum of a gravity wave parameterization in a general circulation model. Results from two simulations with the gravity wave spectrum launched at two different heights, the surface and the 110-hPa pressure level, respectively, are compared. Noteworthy differences found in the simulated middle atmosphere response include the following (1) The average temperature in the southern winter upper stratosphere is about 40 K warmer in the experiment with the surface as the launching height, virtually eliminating the typical cold polar bias that affects many general circulation models. (2) Stronger easterlies in the subtropical summer mesosphere, again in the experiment with the surface as the launching height. Diagnostics of the parameterized gravity waves indicate that in the experiment with the surface as the launching height, the net zonal momentum flux transported by the gravity waves is negative just above the troposphere at middle latitudes. This negative net momentum flux facilitates the deceleration of the mesospheric winter westerlies. The meridional circulation induced by such deceleration is thereafter responsible for the substantial polar winter warming. In contrast, in summer the negative net momentum flux limits the upper mesospheric deceleration of the easterlies. In the experiment with launching height at 110-hPa, the gravity wave net momentum flux is instead zero by construction at the launching height

    Sustainable qualities: Powerful drivers of social change

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    Looking attentively at the complexity of contemporary society, we can detect a variety of creative communities involved in sustainable social innovation. Behind each of these initiatives stands a group of people who have been able to imagine, develop and manage something new, beyond the standard ways of thinking and doing. They have succeeded in challenging the apparent hegemony of mainstream ideas about how problems need to be solved by providing valuable alternatives. A primary common feature of such creative communities is that most of them have sprung from collaboratively confronting the problems of everyday life. Facing up to these, they have conceived new models of thought and action where everybody wins – individuals, society and the environment. A second common feature is that they produce and are, in turn, driven by new notions of qualities: new qualities of their physical and social environments. We can refer to these as sustainable qualities: qualities that require more sustainable behaviours in order to enjoy their beneïŹts

    Forcing of the quasi-biennial oscillation from a broad spectrum of atmospheric waves

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    [1] The circulation of the stratosphere, and its influence on the trace constituent distribution, is an important component of the climate system, which must be included in simulations of global climate change. However, the ability to simulate a dominant stratospheric phenomenon, the Quasi-Biennial Oscillation (QBO) in equatorial zonal wind, is an outstanding challenge in climate modeling. Although confined to the tropics, the QBO affects the circulation and the interannual variability of the entire stratosphere, parts of the mesosphere and possibly also of the troposphere. Here we show that the QBO is successfully simulated in a general circulation model (GCM) of the newest generation. Key factors are a sufficient spatial resolution, a realistic simulation of tropical convection, and the consideration of the effects of gravity waves. From this simulation it is inferred that a broad spectrum of atmospheric waves is necessary to generate the QBO in the model

    High-Order IMEX-RK Finite Volume Methods for Multidimensional Hyperbolic Systems.

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    In this paper we present a high-order accurate cell-centered finite volume method for the semi-implicit discretization of multidimensional hyperbolic systems in conservative form on unstructured grids. This method is based on a special splitting of the physical flux function into a convective and a non-convective part. The convective contribution to the global flux is treated implicitly by mimicking the upwinding of a scalar linear flux function while the rest of the flux is discretized in an explicit way. The spatial accuracy is ensured by allowing non-oscillatory polynomial reconstruction procedures, while the time accuracy is attained by adopting a Runge-Kutta stepping scheme. The method can be naturally considered in the framework of the textbf{IM}plicit-textbf{EX}plicit (IMEX) schemes and the properties of the resulting operators are analysed using the properties of M-matrices

    Reconciling different methods of high‐latitude blocking detection

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    Blocking is associated with outbreaks of easterlies induced by a continuum of features including anticyclones, cyclones or both. Blocking identification methods disagree on the levels of high-latitude blocking (HLB) activity. We investigate the cause of the disagreement in HLB activity over the Northern Hemisphere obtained by two 2D methods: the PV– (Formula presented.) index and the Absolute Geopotential Height (AGH) reversal method. Although both classify as absolute field methods, the former yields nearly twice the winter HLB activity of the latter method. We show that this discrepancy is caused by the addition of a poleward criterion in the AGH method that requires strong poleward westerlies. The additional criterion in the AGH method shifts the focus on the detection of blocking ridges and thus other blocking circulation patterns are under-represented. Both methods agree on the climatology of midlatitude blocking because the poleward criterion has been tuned to capture the strong midlatitude blocking, but the discrepancy grows in high latitudes. HLBs are different because they occur on the northern flank of the westerlies and are associated with the equatorward displacement of the midlatitude jet. HLB anticyclones are weaker and do not induce strong poleward westerlies compared to their midlatitude counterparts. The implementation of a strict poleward criterion designed to identify midlatitude blocks rejects many HLBs. The use of the less strict cut-off threshold (CT) of 0 m (°lat)−1 in the poleward criterion for latitudes higher than 60°N results in the convergence of climatology, interannual variability and trends of HLB between the two methods, especially during winter. The additional HLBs identified by the modified AGH algorithm develop from cyclonic wave breaking that is typical for oceanic blocking. The modified AGH method can be useful in detecting more robust HLB trends in climate model projections. © 2020 The Authors

    Scheduling Jobs in Flowshops with the Introduction of Additional Machines in the Future

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    This is the author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/expert-systems-with-applications/.The problem of scheduling jobs to minimize total weighted tardiness in flowshops,\ud with the possibility of evolving into hybrid flowshops in the future, is investigated in\ud this paper. As this research is guided by a real problem in industry, the flowshop\ud considered has considerable flexibility, which stimulated the development of an\ud innovative methodology for this research. Each stage of the flowshop currently has\ud one or several identical machines. However, the manufacturing company is planning\ud to introduce additional machines with different capabilities in different stages in the\ud near future. Thus, the algorithm proposed and developed for the problem is not only\ud capable of solving the current flow line configuration but also the potential new\ud configurations that may result in the future. A meta-heuristic search algorithm based\ud on Tabu search is developed to solve this NP-hard, industry-guided problem. Six\ud different initial solution finding mechanisms are proposed. A carefully planned\ud nested split-plot design is performed to test the significance of different factors and\ud their impact on the performance of the different algorithms. To the best of our\ud knowledge, this research is the first of its kind that attempts to solve an industry-guided\ud problem with the concern for future developments

    BIOHYDROGEN PRODUCTION BY DARK FERMENTATION: FROM LABORATORY TO FULL SCALE.

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    Hydrogen is a promising, eco-friendly fuel for the future, especially when obtained from renewable sources such as anaerobic digestion (AD). After proving that biomass'composition is involved in the production of hydrogen, a comparison between single- and two-stage AD showed that the latter is not less convenient than the classical, single stage process. The addition of a further stage (microbial fuel cells) to AD reactors showed an interesting perspective for two-stage AD, which resulted in better total energy yields when compared to single-stage process. The process is feisable on full scale, but technical issues are to be solved in order to obtain better performances
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