Optimised thermosyphon solar hot water heater — simulation, design and experimental analysis

Thermosyphon systems represent 70–80 % of the solar-thermal capacity installed world-wide. Outside of China — the world’s largest thermosyphon system market — thermosyphon systems using flat-plate collectors are the dominant configuration. In Southern Europe conventionally-designed thermosyphon systems with a collector area of about 2.0 m² and a storage tank of 180 l are able to deliver about 70 % of the annually needed hot water of a four person household. However, research into the performance of thermosyphon systems has stagnated in recent years, hence the primary objective of this research was to evaluate in detail the physical factors affecting the performance of flat plate thermosyphon systems hence pointing the way towards improved performance. The investigation consisted of the implementation of a detailed dynamic system simulation, which included the development of new component models, the validation of the new component models via laboratory testing, the use of the system model in a sensitivity analysis of the significance of individual component performance and finally the testing of an improved prototype thermosyphon system. Eighteen different geometrical and physical parameters were investigated in the sensitivity analysis to find the most significant design factors. The sensitivity analysis incorporated three different European locations, but the dependency of the optimal thermosyphon system configuration on the location was found to be rather weak. The research concluded that a performance improvement from 70 % to 85 % of the hot water demand of a four-person household could be achieved with an improved system configuration. The improved system prototype addressed cost reduction by the material selection for the storage tank and its built-in components as well as the selection of aluminium for the solar absorber and the use of prefabricated parts for the system support. Reverse thermosyphoning was prevented by adjusting the tank and collector inlet/outlet co-locations, while the availability of hot water was enhanced by improved hydraulic design of the storage tank. Suggestions for further work included the development of more detailed component models and long-term testing of improved system configurations

What is going on between aposematic carabide beetles? The case of Anchomenus dorsalis (Pontoppidan, 1763) and Brachinus sclopeta (Fabricius, 1792) (Coleoptera, Carabidae)

Interspecific aggregations among insects are quite common, but not among carabid beetles. Moreover, aggregations of aposematic species, and morphologically similar beetles such as Anchomenus dorsalis and Brachinus sclopeta are even rarer. Most interestingly, in these aggregations, we observed a peculiar rubbing behaviour of A. dorsalis towards B. sclopeta. In this study we aimed (i) to verify if A. dorsalis displays the rubbing behaviour towards non-aposematic species, (ii) to describe in detail and to quantify this behaviour between A. dorsalis and B. sclopeta, and (iii) to verify if previous experience of inter-specific gregariousness with the same species may exert some effects on the frequency of the rubbing display. We have investigated the qualitative and quantitative characteristics of rubbing behaviour towards aposematic and non-aposematic carabide beetle species, and then we used A. dorsalis and B. sclopeta as model species. We tested the rubbing of A. dorsalis towards B. sclopeta with either solitary A. dorsalis or in A. dorsalis coming from monospecific (A. dorsalis) or from heterospecific (A. dorsalis and B. sclopeta) aggregations. We finally tested the effectiveness of the B. sclopeta cuticular odour in eliciting rubbing from A. dorsalis by presenting olfactory dummies (special paper) either soaked with water or after it had previously been placed in a monospecific group of B. sclopeta for 15 days. First of all, we found important differences in the occurrence of rubbing behaviour towards aposematic and non-aposematic species, as A. dorsalis displayed the rubbing only towards the former. Secondly, rubbing frequency depended on the pre-test conditions (isolated, mono- or heterospecific aggregations) of the tested A. dorsalis individuals, as no rubbing occurred in individuals coming from heterospecific aggregations. The paper presentation tests demonstrated that the odour of B. sclopeta was sufficient to provoke rubbing in A. dorsalis. We conclude that aggregation in these species of carabid beetles may influence their anti-predatory defences possibly increasing the effectiveness of the aposematic (warning) signals. More work is needed to delineate in detail the evolutionary significance of this behaviour, focusing on the possibility that interspecific aggregations may not be so rare in ground beetles, and that this positive interaction could involve a larger number of species and genera, at least in wet, sun-exposed and open land habitat types

IBP′: A New Index to Estimate Biogeographical Peculiarity

The biogeographical peculiarity of a given geographical area is directly linked to the number of its endemic species. This paper aims to formulate an index directly linked to the biogeographical peculiarity of an area. A graphical model and an index of the biogeographical peculiarity are proposed, based on a cumulative sum (i.e., including all the amounts that were added previously). An example of the computations is proposed, based on the number of different types of geographical ranges (i.e., chorotypes) characterizing two different ecosystems; their biogeographical peculiarity of was evaluated on the basis of presence versus absence of carabid species. Both the graphical model and the index mirrored the different faunistic compositions of the ecosystems, because the index reached a higher value where more endemic species have been found. Our investigation has found a new method for evaluating the biogeographical peculiarity of a given area or biota in a simple way. The index could be used for either conservation biogeography (e.g., monitoring of biotic homogenization) or for theoretical studies integrating ecology and biogeography

Public Epistemologies and Intellectual Interventions in Contemporary Italy

Funder: University of CambridgeAbstract: Building on recent work in the sociology of intellectual interventions, the study of cultural boundaries of science, and the role of ideas in politics, the article develops a theory of public epistemologies as argumentative tools people use to support or oppose political positions. Two prominent public epistemologies that have recently crystallized in Italian politics are taken as illustrations, with special attention paid to the role of two academics (an economist and an immunologist) turned public intellectuals. The article argues that the rise of populism in Italy has contributed to unusual alignments between political and epistemological positions, which has made questions about science and expert knowledge much more relevant in contesting and supporting political decisions

Agonistic behaviour of Scarites buparius (Forster, 1771) (Coleoptera: Carabidae) in relation to body size

Intra-male aggressive behaviour of Scarites buparius was analysed; agonistic interaction between males consisted of a repeated series of fighting events. We defined this behaviour as “agonistic” because a dominance/submission status was established. We measured the males and found that the attack behaviour persistence is correlated with the body length

Public Epistemologies and Intellectual Interventions in Contemporary Italy

Funder: University of CambridgeAbstract: Building on recent work in the sociology of intellectual interventions, the study of cultural boundaries of science, and the role of ideas in politics, the article develops a theory of public epistemologies as argumentative tools people use to support or oppose political positions. Two prominent public epistemologies that have recently crystallized in Italian politics are taken as illustrations, with special attention paid to the role of two academics (an economist and an immunologist) turned public intellectuals. The article argues that the rise of populism in Italy has contributed to unusual alignments between political and epistemological positions, which has made questions about science and expert knowledge much more relevant in contesting and supporting political decisions

Social science as apologia

The social sciences are predominantly seen by their practitioners as critical endeavours, which should inform criticism of harmful institutions, beliefs and practices. Accordingly, political attacks on the social sciences are often interpreted as revealing an unwillingness to accept criticism and an acquiescence with the status quo. But this dominant view of the political implications of social scientific knowledge misses the fact that people can also be outraged by what they see as its apologetic potential, namely that it provides excuses or justifications for people doing bad things, preventing them from being rightfully blamed and punished. This introduction to the special issue sketches the long history of debates about the exculpatory and justificatory consequences of social science and lays the foundations for a theory of social scientific apologia by examining three main aspects: what social and cognitive processes motivate this type of accusation, how social theorists respond to it and whether different contexts of circulation of ideas affect how these controversies unfold.</jats:p