86 research outputs found

    On the Complexity of Anchored Rectangle Packing

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    Novel synthesis and electrochemical investigations of ZnO/C composites for lithium-ion batteries

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    For the first time, ZnO/C composites were synthesized using zinc glycerolate as a precursor through one-step calcination under a nitrogen atmosphere. The effect of the heat treatment conditions on the structure, composition, morphology as well as on the electrochemical properties regarding application in lithium-ion batteries are investigated. The products obtained by calcination of the precursor in nitrogen at 400—800 °C consist of zinc oxide nanoparticles and amorphous carbon that is in-situ generated from organic components of the glycerolate precursor. When used as anode material for lithium-ion batteries, the as-prepared ZnO/C composite synthesized at a calcination temperature of 700 °C delivers initial discharge and charge capacities of 1061 and 671 mAh g−1 at a current rate of 100 mA g−1 and hence 1.5 times more than bare ZnO, which reaches only 749/439 mAh g−1. The native carbon improves the conductivity, allowing efficient electronic conductivity and Li-ion diffusion. By means of ex-situ XRD studies a two-step storage mechanism is proven. © 2021, The Author(s).This work was supported by the Deutsche Forschungsgemeinschaft through projects KL1824/12-1 and KL 1824/14-1. G.Z. acknowledges support of the state order via the Ministry of Science and Higher Education of Russia (No AAAA-A19-119031890025-9). E.T. acknowledges support by the BMWi through project 03ET6095C (HiKoMat). The authors thank I. Glass for experimental support

    National Government Responses to Marine Stewardship Council (MSC) Fisheries Certification: Insights from Atlantic Canada

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    Over the last decade, the proliferation of social and environmental certification programmes has attracted the attention of a growing number of political scientists interested in new forms of ‘private’ transnational governance. However, we still lack analyses on the nature and extent of different state responses to and involvement in new private transnational governance arrangements in particular sectors and in different jurisdictions. This paper advances our understanding of the interactions between nation-state and private transnational modes of governance by analysing the role of national government authorities in Marine Stewardship Council (MSC) fisheries certification in Atlantic Canada, known more for the disastrous collapse of Northern cod stocks than good marine stewardship. Focusing on the 2008 certification of Northern shrimp (Pandalus borealis) fisheries off the Province of Newfoundland and Labrador, the analysis finds that the implementation and maintenance of MSC certification in this case depended on significant support from government authorities. The delicate legitimacy of both authorities face a period of uncertainty in this case since some certified shrimp stocks appear to be in decline and perhaps also migrating northward off Newfoundland and Labrador

    Coronal voids and their magnetic nature

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    Context: Extreme ultraviolet (EUV) observations of the quiet solar atmosphere reveal extended regions of weak emission compared to the ambient quiescent corona. The magnetic nature of these coronal features is not well understood. // Aims: We study the magnetic properties of the weakly emitting extended regions, which we name coronal voids. In particular, we aim to understand whether these voids result from a reduced heat input into the corona or if they are associated with mainly unipolar and possibly open magnetic fields, similar to coronal holes. // Methods: We defined the coronal voids via an intensity threshold of 75% of the mean quiet-Sun (QS) EUV intensity observed by the high-resolution EUV channel (HRIEUV) of the Extreme Ultraviolet Imager on Solar Orbiter. The line-of-sight magnetograms of the same solar region recorded by the High Resolution Telescope of the Polarimetric and Helioseismic Imager allowed us to compare the photospheric magnetic field beneath the coronal voids with that in other parts of the QS. // Results: The coronal voids studied here range in size from a few granules to a few supergranules and on average exhibit a reduced intensity of 67% of the mean value of the entire field of view. The magnetic flux density in the photosphere below the voids is 76% (or more) lower than in the surrounding QS. Specifically, the coronal voids show much weaker or no network structures. The detected flux imbalances fall in the range of imbalances found in QS areas of the same size. // Conclusions: We conclude that coronal voids form because of locally reduced heating of the corona due to reduced magnetic flux density in the photosphere. This makes them a distinct class of (dark) structure, different from coronal holes

    FDI in hot labour markets: The implications of the war for talent

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    This paper highlights an inherent contradiction that exists within investment promotion activities in rich countries. Since the financial crisis, many inward investment agencies have shifted their activities from job creation per se to seeking to attract investment in high-tech activities. Such knowledge-intensive sectors are engaged in what has become referred to as “the war for talent”, so locations need to understand their value proposition to firms, especially where labour is tight. This paper explores the implications of this, in terms of the impact on employment and earnings of high skilled labour. We show that, because skill shortages already exist in many of these sectors, seeking to attract inward investment in these sectors simply causes the earnings of such workers to be bid up, and employment in the incumbent sector to fall. We highlight the over-riding importance that firms place on the availability of skilled labour when determining locations, and how policies which promote labour market flexibility, particularly through investment in skills to address skill shortages, can significantly mitigate the adverse effects, which tend to be more keenly felt in poorer regions of Europe where skilled labour is in even shorter supply
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