A Particle Image Velocimetry study of dual-rotor counter-rotating wind turbine near wake

This experimental work studied the flow characteristics in the near wake region behind dual-rotor wind turbines using two-dimensional particle image velocimetry. Two auxiliary rotors of 50% and 80% scale of the main rotor were installed upwind and operated in counter-rotating condition, which are compared to the conventional single rotor turbine. In all the three configurations, a constant Reynolds number 9.5×104 was applied and all the rotors operated at a fixed tip speed ratio of 3.46. The mean and phase averaged velocity fields were investigated together with the turbulence kinetic energy. It was found that the two auxiliary rotors do not result in a significantly different wake flow property. The configuration implementing the 50% auxiliary rotor sees a slightly better wake characteristics, in terms of weaker main rotor tip vortices and a counter-rotating swirling shear region at the mid-span behind the main rotor. The decay rates of the peak vorticity of the main rotor tip vortices and their circulation are found to follow an exponential manner

Healthy people with nature in mind

This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND: The global disease burden resulting from climate change is likely to be substantial and will put further strain on public health systems that are already struggling to cope with demand. An up- stream solution, that of preventing climate change and associated adverse health effects, is a promising approach, which would create win-win-situations where both the environment and human health benefit. One such solution would be to apply methods of behaviour change to prompt pro-environmentalism, which in turn benefits health and wellbeing. DISCUSSION: Based on evidence from the behavioural sciences, we suggest that, like many social behaviours, pro- environmental behaviour can be automatically induced by internal or external stimuli. A potential trigger for such automatic pro-environmental behaviour would be natural environments themselves. Previous research has demonstrated that natural environments evoke specific psychological and physiological reactions, as demonstrated by self-reports, epidemiological studies, brain imaging techniques, and various biomarkers. This suggests that exposure to natural environments could have automatic behavioural effects, potentially in a pro-environmental direction, mediated by physiological reactions. Providing access and fostering exposure to natural environments could then serve as a public health tool, together with other measures, by mitigating climate change and achieving sustainable health in sustainable ecosystems. However, before such actions are implemented basic research is required to elucidate the mechanisms involved, and applied investigations are needed to explore real world impacts and effect magnitudes. As environmental research is still not sufficiently integrated within medical or public health studies there is an urgent need to promote interdisciplinary methods and investigations in this critical field. Health risks posed by anthropogenic climate change are large, unevenly distributed, and unpredictable. To ameliorate negative impacts, pro-environmental behaviours should be fostered. Potentially this could be achieved automatically through exposure to favourable natural environments, with an opportunity for cost-efficient nature-based solutions that provide benefits for both the environment and public health

Two Virasoro symmetries in stringy warped AdS3_3

41 pages, 1 figureInternational audienceWe study three-dimensional consistent truncations of type IIB supergravity which admit warped AdS$_3$ solutions. These theories contain subsectors that have no bulk dynamics. We show that the symplectic form for these theories, when restricted to the non-dynamical subsectors, equals the symplectic form for pure Einstein gravity in AdS$_3$. Consequently, for each consistent choice of boundary conditions in AdS$_3$, we can define a consistent phase space in warped AdS$_3$ with identical conserved charges. This way, we easily obtain a Virasoro X Virasoro asymptotic symmetry algebra in warped AdS$_3$; two different types of Virasoro X Kac-Moody symmetries are also consistent alternatives. Next, we study the phase space of these theories when propagating modes are included. We show that, as long as one can define a conserved symplectic form without introducing instabilities, the Virasoro X Virasoro asymptotic symmetries can be extended to the entire (linearized) phase space. This implies that, at least at semi-classical level, consistent theories of gravity in warped AdS$_3$ are described by a two-dimensional conformal field theory, as long as stability is not an issue

Spatial and economic smart strategies for the 21st-Century metropolitan city of Naples.

The assumption of Neoliberalism in the economy has multiplied exponentially financing speculation, and produced several “distortions” both in the social system and in the job market: the destruction of a welfare program, the attack to the right of the labor market and workers right, the powerful growing of financial institutions supported by the ICT. This means the need to identify a new epistemological approach, suggesting a conceptual framework for ecological economics based on systemic principles of life and a shift from techno-city to a human city. A model, called the homological smart city, could be a new way, based on direct citizen participation, peer-to-peer community, neuroergonomics, biophilic design, and biourban economics. The operational character of this model is explored by analyzing the most recent Italian experiences in reaction to the diffused crisis conditions. Several villages, towns and cities have seen a slow phenomenon of the revival of local communities, for the merit of grassroots’ initiatives of social innovation constituted mostly of young people that, leveraging on their capabilities and a peer-to-peer network supported by the ICT, promote a novel vision for the future of their community, building a more sustainable urban system. Through a change of paradigm, the human being is put at the centre of the system and its designing, considering social innovators as the key actors of change and local assets as the key resources for the implementation of Biourbanism principles. In the above perspective, the experience of a new biourban strategy named “mushrooming”, implemented in Finland, constitutes a good example of practice-oriented to consider diversification as a principle of life in a city and developed by testing with real-life conditions. The Finnish experience was started to build a network to foster interaction between small self-organized co-working communities, by taking into account spatial and economic processes that emerged due to this. These processes were able to activate connected diversification, recognized as a systemic principle of life that fits the context of urban development especially well. The principle of connected diversification drives the methodological process structured for the case study of the Metropolitan City of Naples, one of the 14 Italian metropolitan cities, with a specific attention for the 16 municipalities of the Coast Area. Starting from vulnerability and resilience concepts, the study dealt according to a multi-methodological approach, based on a GeoDesign process supported by multi-criteria analysis, multi-group analysis, and spatial analysis. The elaboration of Spatial Opportunity Maps (SOMs) is the output of a multidimensional evaluation process that leads to the identification of a biourban strategy, characterized by human smart spatial solutions, place-based and situated actions. The enhancement of the coastal area of the Metropolitan City of Naples can be considered as a prerequisite for the activation of a process-oriented to the identification of “homogeneous zones”, conceived not only as areas with similar characteristics but, above all, as territories where it is possible to promote networks of opportunities between the various municipalities and their communities. Cooperation has conceived a source of mutual benefit and involves a mutual convenience, based on the constant construction of bonds and relationships and the interdependence determined by spatial proximity. Economic processes require cooperative-collaborative behaviours between the various components and become increasingly territorialised, and therefore more resilient and, at the same time, less and less associated with the production of negative environmental impact.N/