Search

Measuring habitat specialisation is pivotal for predicting species extinctions and for understanding consequences on ecosystem functioning. Here, we sampled pollinator and natural enemy communities in all major habitat types occurring across multiple agricultural landscapes and used species-habitat networks to determine how habitat specialisation changed along gradients in landscape composition and configuration. Although it is well known that landscape simplification often causes the replacement of specialists with generalists, our study provided evidence for intraspecific variation in habitat specialisation, highlighting how a large number of arthropod species adapted their way of selecting habitat resources depending on the landscape structure. Groups with higher diet specialisation and limited foraging flexibility appeared to have a reduced ability to respond to landscape changes, indicating that some arthropod taxa are better able than others to adapt to an increasingly broad set of resources and persist in highly impacted landscapes.

European coniferous forests are currently threatened by bark beetles (e.g. Ips typographus) because of an increasing incidence of triggering factors, such as drought and windstorms. Furthermore, such natural disturbances are expected to increase in terms of magnitude and frequency due to climate change, and thus interacting with each other. Here, we present a particular case study in the Southern Italian Alps (Gares, Canale d’Agordo, Belluno), in which wind disturbance interacts with an ongoing outbreak of I. typographus, probably associated with an extended drought in the previous three years. By combining remote sensing and field surveys, we spatially reconstructed the bark beetle attack in the period 2015-2021, which includes the Vaia windstorm in October 2018. Although the windstorm occurred in an expanding phase of the bark beetle outbreak, attacks on standing trees did not occur during the first year after the windstorm but were observed two years later. Our findings suggest that an overlap of a large availability of wind felled trees with an incipient outbreak of I. typographus resulted in an immediate decrease of standing trees mortality in the year following the storm. However, the fallen trees worked as a hidden sink for the beetle population, which in the following years massively attacked the standing trees that survived the storm.

This paper provides a methodology for the application of a machine learning-based framework for fused deposition modelling manufacturing. The approach was developed to take into account the influence of the material, the part geometry, the process parameters on the maximum part warpage defined by the user. The results showed the effectiveness of machine learning for both classification and regression purposes so that the printability of the part is firstly provided, based on the selected warpage threshold, and secondly, the part warpage can be predicted within the problem design space variables, i.e. part material, part height, part length, and layer thickness. The limitations of the use of the analytic equation as a data-points generator are widely discussed, along with the future research based on the obtained preliminary results. In conclusion, the described methodology represents a concrete step towards a first-time-right strategy in the field of manufacturing processes.

Although arthropods are among the most diverse, abundant and ecologically important animals in terrestrial ecosystems, they are generally neglected in most biodiversity inventories due to their complex systematics and overwhelming diversity, coupled with the current decline in the number of taxonomists. For this reason, several surrogate groups for arthropod diversity have been proposed, with plants being identified as a good putative cross-taxon indicator. By sampling plants and three groups of ground-dwelling arthropods (rove beetles, ground beetles and spiders) in 300 sites across 15 landscapes including multiple semi-natural and agricultural habitats, we tested for habitat-dependence and scale-dependence in the cross-taxon congruence. Plant species richness was a poor predictor of the species richness of predatory arthropods. Among the predator groups, ground beetles appeared as the best potential surrogate for the other ground-dwelling predators. This is backed by the fact that ground beetles were extremely diverse and abundant in all habitats and are usually easier to identify than both rove beetles and spiders. Decreasing the scale at which the cross-taxon congruence was tested improved the strength of the cross-taxon congruence. Although plant species richness was not a suitable indicator for the diversity of predatory arthropods, vegetation structure played a significant role in influencing cross-taxon congruence in both natural and agricultural habitats. Our results highlight the need to explore the cross-taxon relationships at a fine habitat resolution scale, as strong correlations were obtained only by taking into account habitat identity.

In the last decades, the transformation of agriculture and the associated decline in semi-natural grasslands have been major drivers of the loss of spider diversity across Europe, in particular in mountain regions. In the early stages of forest succession, abandoned grasslands exhibit a complex vegetation structure sharing environmental conditions with both open habitats and forests. At the landscape scale, the occurrence of abandoned patches can potentially provide novel habitats and niches for ground-dwelling spiders. Here, we used two complementary methods: traditional species diversity analyses and species-habitat networks to understand how abandoned grasslands can interact with the surrounding habitat mosaic in supporting spider communities. We selected six landscapes along an elevational gradient and sampled spiders in all the major agricultural and semi-natural habitats occurring across the landscapes. At all elevations, we found a similar species richness and activity density between agricultural habitats (i.e. meadows, pastures, and crop fields) and abandoned grasslands. On the contrary, we consistently found lower species richness and activity density in forests than in all open habitats. Despite the similar diversity between open habitats, most species-habitat networks exhibited a high and constant modularity, i.e. the same species tended to occur in a specific habitat type and not in the others. Only a few species were shared between abandoned and agricultural habitats, indicating that abandoned grasslands cannot support populations of most species typical of open managed habitats. Early abandoned patches increased landscape habitat heterogeneity providing unique niches to spider species that, however, rarely occur in other habitats. The maintenance of multiple habitat types across the landscape is expected to increase the regional species pool, while the role of abandoned patches as surrogate habitat for the conservation of spider species typical of semi-natural grasslands appeared limited. Similarly, abandoned patches are not expected to help maintaining the populations of spider species occurring in agricultural habitats.

Fibre metal laminates (FML) are hybrid materials perspective for wind-turbine, containers and marine objects, besides the aerospace industry. During the manufacturing process some faults can occur and can be hazardous for the reliability of FML structures. One of the most critical defects are kissing bonding due to their lack of detectability and strength compared to traditional delamination defect. The quantitative explanation were under consideration, such as loads effects; material properties; prediction of response; fracture analysis . The purpose of this work is the evaluation the impact of this type of defect on the part in-plane and the out-of-plane mechanical properties. It was presented that even responsive NDT methods are not able to detects the kissing bonding defect in FML components. Simultaneously, the kissing bonding impact on mechanical properties in FML is significant. In the case of FMLs with the orientation of the fibre perpendicular to the peel direction there is one failure pattern which is interlayer fracture. Whereas in the case of FMLs with the direction of the fibres longitudinal to the peel direction two failure patterns occur which is interlayer fracture and translaminar fibre crack. Depending on the kissing bonding area width the interlayer fracture in the composite can be observed until kissing bonding defect area and then transmission of the crack to the metal/composite interface through the fibres. In the case of low extension of poor adhesion area, the two parallel interlaminar cracking can be seen, one at the metal/composite interface in poor adhesion area, the second continuous in the composite layer.

Land-use intensification is a major threat to arthropods across agricultural landscapes. To mitigate these negative effects through appropriate landscape management, it is necessary to understand how entire species communities respond to land-use at the landscape scale. We performed a whole-landscape sampling of spiders in 300 habitat patches across 15 landscapes and built species-habitat networks to evaluate the impact of compositional and configurational simplification on network modularity and habitat specialisation. Within each landscape mosaic, spiders showed a high degree of habitat selectivity, i.e. patches of the same habitat type tended to cluster into modules that rarely interacted with each other. Although spiders are expected to disperse between habitat patches more often when landscapes are fragmented, their high modularity and habitat selectivity were not influenced by edge density. However, modularity was the highest at intermediate cover of semi-natural habitats, probably due to the simultaneous presence of multiple habitats with sufficient area to support the associated specialist species. Despite the high habitat selectivity, perennial crops and meadows seemed to play a central role in connecting different habitat modules across the landscapes. On the contrary, forest and hedgerows hosted very distinct species communities that did not occur outside woody habitats. Encouraging the spill-over of spiders from semi-natural habitats to crops to enhance biological control might be more effective for the better-connected permanent crops, while for annual crops it would be more effective to improve local field quality for crop specialists or to introduce open semi-natural habitats such as meadows.

The paper addresses the role played by the cure stage of a vacuum assisted resin transfer molding process in residual stresses generation. The Airstone 780E epoxy resin and Hardener 785H system broadly used in the wind turbine blade industry has been used in this study. The viscous–elastic properties of the resin have been characterized and implemented in a thermo-mechanical FE model. The model has been validated against manufactured [0/90]4 asymmetric laminates. Analysis of residual stresses generation highlighted that compressive stresses generation occurs when the cure is shrinkage dominated and tensile stresses when expansion dominated in the 0° plies. The finding points out that 10% reduction in warpage and 33% reduction in process time can be obtained by selecting cure cycle parameters that allow tensile stresses development during the cure process in the 0° plies.

The manufacturing of Fibre Metal Laminates, consisting of alternating layers of pre-preg fibre and metal is complex, and defects can be introduced during manufacturing. The automation of the manufacturing steps is vital for future Glare production, and specific defects have to be considered. Among them, gaps between pre-preg plies represent a potential risk for the mechanical performances of the laminate. In this paper/research, non-destructive testing based on ultrasonic inspections are performed on Glare with pre-preg gaps in order to extend and improve the current state of the art to different pre-preg gap widths, depths, and lay-ups. Firstly, gaps were introduced in Glare specimens. Then, a conventional C-scan ultrasonic inspection is performed. In order to overcome the current limitations of a top or planar view of the laminates, the evaluation of the depth of the gaps in the laminates is performed by means of phased array ultrasonic testing. Finally, images of the laminate cross-section have been collected in order to provide a meaningful evidence of the ultrasonic-based analysis. Results from different Glare and gap widths and depths show the accuracy of the proposed investigation which is able to provide a detailed assessment of the gap occurrences also for very thin laminates.

During the automated manufacturing of fibre reinforced laminates, defects can be produced. Gaps and overlaps between adjacent prepreg layers can be produced in composites during the tape-layup process. However, the topic is not yet studied for hybrid materials, in which metal sheets and thin prepreg layers lead to different effects due to the defects than in full composites. Here, the effect of gaps and overlaps on the mechanical properties of the Fibre metal laminates (FML) is evaluated. Specimens are manufactured with a specified width of gaps/overlaps and the mechanical performance of the panels is evaluated by some selected mechanical tests. Gaps show to have a considerable effect on the mechanical performance of FML. Compression strength of samples with overlaps was rather increased. Discussions are presented on the influence on each mechanical property according to the severity of the defect (gaps/overlap) and the failure mode(s) under consideration.

Gaps and overlaps between pre-preg plies represent common flaws in composite materials that can be introduced easily in an automated fibre placement manufacturing process and are potentially detrimental for the mechanical performances of the final laminates. Whereas gaps and overlaps have been addressed for full composite material, the topic has not been extended to a hybrid composite material such as Glare, a member of the family of Fibre Metal Laminates (FMLs). In this paper/research, the manufacturing, the detection, and the optical evaluation of intraply gaps and overlaps in Glare laminates are investigated. As part of an initial assessment study on the effect of gaps and overlaps on Glare, only the most critical lay-up has been considered. The experimental investigation started with the manufacturing of specimens having gaps and overlaps with different widths, followed by a non-destructive ultrasonic-inspection. An optical evaluation of the gaps and overlaps was performed by means of microscope image analysis of the cross sections of the specimens. The results from the non-destructive evaluations show the effectiveness of the ultrasonic detection of gaps and overlaps both in position, shape, width, and severity. The optical inspections confirm the accuracy of the non-destructive evaluation also adding useful insights about the geometrical features due to the presence of gaps and overlaps in the final Glare laminates. All the results justify the need for a further investigation on the effect of gaps and overlaps on the mechanical properties.

The paper presents the operational results of a real life residential microgrid which includes six apartments, a 20 kWp photovoltaic plant, a solar based thermal energy plant, a geothermal heat pump, a thermal energy storage, in the form of a 1300 l water tank and two 5.8 kW h batteries supplying, each, a couple of apartments. Thanks to the thermal energy storage, the solar based thermal energy plant is able to satisfy the 100% of the hot water summer demand. Therefore the thermal energy storage represents a fundamental element in the management of the residential demand of thermal energy. It collects renewable thermal energy during day-time to release it during night-time, effectively shaving the peak of the thermal energy demand. The two electric storages, on the other hand, provide the hosted electrical subsystems with the ability to effectively increase the self-consumption of the local energy production, thus lowering the amount of energy surplus to be sold back to the grid, and increasing the self-sufficiency of the microgrid. For instance, the storage has supported self-consumption up to the 58.1% of local energy production with regard to the first battery, and up to the 63.5% with regard to the second one. Also, 3165 and 3365 yearly hours of fully autonomous activity have been recorded thanks to the first, and the second battery respectively. On the other hand, the yearly average efficiency amounts to 63.7%, and 65.3% respectively, for the first and second battery. In the second part of the paper we propose a computational framework to evaluate the overall performance of the microgrid system, while accounting different operating conditions and energy management policies. From this perspective, the framework acts as a useful modeling and design tool, to assess the opportunity of employing alternative energy management system topologies and strategies. Eight different configurations, with growing complexity, have been derived from the original system on purpose. The simulations, carried out based on real data related to one-year time period, have provided results showing that, the higher the integration level of electrical and thermal storage is, the higher degree of self-sufficiency can be achieved by the microgrid, and, in turn, the more consistent the yearly energy saving become. Nevertheless, despite the energy cost reduction achievable with the availability of storage systems in the Leaf House, their high investment cost made them not really profitable at the current price conditions for devices and energy purchase.

The quality control of Glare panels manufacturing is an important and complex process including the evaluation of the quality of the basic constituents, namely the aluminium sheets, and the glass fibre reinforced pre-preg. In particular, the handling of aluminium sheets is one of the most critical steps for the manufacturing of Glare laminates. The unintentionally induced deformations, referred to as kinks, can significantly affect the geometry and the mechanical properties of the final laminate. This paper considers the effects of kinks in Glare laminates by developing a comprehensive investigation based on controlled kink manufacturing in aluminium sheets, non-destructive and destructive evaluation of laminates with kinks, and the impact on the compressive ultimate strength. The results contribute to the understanding of the kink induced defects and to define thresholds for improving future automated laminate manufacturing.

In this paper, the detection of delaminations in carbon-fiber-reinforced-plastic (CFRP) laminate plates induced by low-velocity impacts (LVI) is investigated by means of Auto-Regressive (AR) models obtained from the time histories of the acquired responses of the composite specimens. A couple of piezoelectric patches for actuation and sensing purposes are employed. The proposed structural health monitoring (SHM) routine begins with the selection of the suitable locations of the piezoelectric transducers via the numerical analysis of the curvature mode shapes of the CFRP plates. The normalized data recorded for the undamaged plate configuration are then analyzed to obtain the most suitable AR model using five techniques based on the Akaike Information Criterion (AIC), the Akaike Final Prediction Error (FPE), the Partial Autocorrelation Function (PAF), the Root Mean Squared (RMS) of the AR residuals for different order p , and the Singular Value Decomposition (SVD). Linear Discriminant Analysis (LDA) is then applied on the AR model parameters to enhance the performance of the proposed delamination identification routine. Results show the effectiveness of the developed procedure when a reduced number of sensors is available.

The idea of a Net ZEB arises from the development of design criteria and construction methods, addressed to curb the operating energy, increasing the energy efficiency of building equipment and appliances, and of the thermal insulation of envelope components, and enhancing the on-site energy generation, by means of renewable energy sources, to cover the annual building energy loads. In this chapter, the energy and environmental performances of an Italian nearly Net ZEB following a life cycle approach are carried out. Then, a scenario of refurbishment is foreseen in order to shift the studied building from the nearly Net ZEB condition toward the Net ZEB target, and the arising energy and environmental benefits are assessed. The life cycle approach in the energy and environmental assessment of the foreseen retrofit options is necessary to avoid shifting environmental burdens from one step of the life cycle to another. Further, in order to get a deeper description of the energy performance of the retrofit actions and to compare the different alternatives, the energy payback time (EPT) and the emission payback time (EPT) are assessed for the proposed solutions.

Δημοσίευση σε επιστημονικό περιοδικό Summarization: The aim of this paper is to present an advanced controller for artificial lights evaluated in several rooms in two European Hospitals located in Chania, Greece and Ancona, Italy. Fuzzy techniques have been used for the architecture of the controller. The energy efficiency of the controllers has been calculated by running the controller coupled with validated models of the RADIANCE back-wards ray tracing software. The input of the controller is the difference between the current illuminance value and the desired one, while the output is the change of the light level that should be applied in the artificial lights. Simulation results indicate significant energy saving potentials. Energy saving potential is calculated from the comparison of the current use of the artificial lights by the users and the proposed one. All simulation work has been conducted using Matlab and RADIANCE environment. Παρουσιάστηκε στο: International Journal of Sustainable Energy

The correct prediction of a composite parts’ final performance is of paramount importance during the initial design phase of the manufacturing process. To this end the correct evaluation of the most effective process parameters and their influence on the parts performance is key for the success of the manufacturing process. Our aim with this paper is to provide methodologies for the prediction of the temperature field in thermoplastic composites during thermoforming and to propose a strategy for process parameter selection. We measured the temperature variations over the different thermoforming stages and compared these values with analytical and finite element results. Our results show the accuracy of the predictions and the importance of the correct laminate temperature with respect to the prediction of the parts’ spring-in angle. We discuss the essential features needed for accurate predictions of the temperature fields over the whole thermoforming process at an early design stage and the potential of a Machine Learning procedure based on Artificial Neural Network to aim for the optimum range of process parameters for a desired part performance outcome. In conclusion, we provide essential guidelines for blank temperature predictions, and the benefit of a machine learning-based tool over traditional approaches.