399 research outputs found

    Tensegrity greenhouse: An innovative covering structural system with low shading

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    Based on the structural principle of “Tensegrity” (tensional integrity), an innovative typology of greenhouse was developed. The principle behind the study uses structural elements of small sections (bars and cables) and employs compressed elements included in a network of tensioned elements. The innovative greenhouse structure allows covering larger spans than the most common greenhouse typologies on the market, improving the surface area usable for crops and reducing the structural sections. The present research focuses on the evaluation of the shading caused by the structural elements inside the tensegrity greenhouse, compared with the most common commercial typologies. At this aim, simulations of illuminance factor (IF) at different distance from the ground level were assessed by means of Revit, a software for building information modelling (BIM), developed by Autodesk Inc., which allows analyzing the impact of natural light and shadows on the interiors of buildings. The IF of the tensegrity greenhouse model (TGM) was compared with the one calculated for different greenhouse typologies (planar pitched roof and vaulted roof) having the same area (118.75 m2) and height of the gutter (3.5 m) placed in Rome (Italy). For all kind of greenhouses, the daily variation of the IF was evaluated in two representative days of the year: June 21 and December 21. As result, the TGM showed a value per square meter of the IF Higher than about 20% compared to traditional structures

    Innovative Tensile Structures for Protected Crop Facilities

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    Greenhouse structures are complex buildings that must meet different needs, such as the microclimate control inside the greenhouse, the strength of structural elements, as well as the radiometric and mechanical features of roofing materials. The covering system must allow the transmission of solar radiation for crop needs and guarantee resistance performances in relation to external actions, such as wind and snow loads. Starting from the main characteristics of agricultural commercial greenhouses and tensile structures, the proposal concerns with an innovative tensile supporting structure designed for the covering of protected crop facilities. The innovative tensile structural configuration was first studied by means of the selection of the construction materials and the cross sections of the structural components and afterward calculated using the structural analysis software SOFISTIK. The load analysis on the structure was carried out in accordance with the European standards UNI-EN 13031-1: 2004 and the Italian Technical Construction Code of 2018 related to the Eurocodes. The main results concern the comparison with the current structural types of commercial greenhouses: analysis of the steel weight of the structure and improvement of the structural response to external actions of the innovative tensile structure

    Plastic nets in agriculture ; a general review of types and applications

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    At the moment, there are a large number of agricultural net types on the market characterized by different structural features such as type of material, type and dimensions of threads, texture, mesh size, porosity / solidity and weight; by radiometric properties like color, transmissivity/reflectivity/shading factor; by physical properties like air permeability and several mechanical characteristics such as tensile stress, strength, elongation at break, and durability. Protection from hail, wind, snow, or strong rainfall in fruit-farming and ornamentals, shading nets for greenhouses and nets moderately modifying the microenvironment for a crop are the most common applications. A systematic review of the current state-of-the-art of structural parameters, standard and regulations, most common agricultural net applications, and their supporting structures has been developed by means of a literature study, technical investigations, concerning characteristics and use of nets. As a result, the survey highlighted that in many cases different, not even similar, net types were adopted for the same application and the same cultivations by various growers. Results show that neither growers nor net producers have clear ideas about the relationship between the net typology optimization for a specific application and the construction parameters of the net. The choice often depends on empirical or economic criteria and not on scientific considerations. Moreover, it appears that scientifically justified technical requirements for nets used in specific agricultural applications have not been established yet

    The current status of the agricultural sciences core curricula in Italian university faculties of agriculture

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    In Italian University Faculties of Agriculture the 1st cycle of studies concerns a BSc. degree offering completed application-oriented studies ensuring employability or an intermediate pivot-point degree towards an integrated MSc. In each first cycle program of studies offered by the Faculties of Agriculture a core curriculum exists and has the scope of providing students with a basic cultural background, common to every program of studies. In Italy the Faculties of Agriculture offer Agricultural Engineering programs of studies and no specialisation both for the 1st and the 2nd cycles of studies. Students can achieve the degree in Agricultural Sciences with a Agricultural Engineering specialisation, although until now no degree fulfils the requirements of FEANI for Engineers. It is possible to create a flexible new Agricultural Engineering 1st cycle program of studies to be implemented in the future, by adopting part of the core curriculum proposed by FEANI program. The learning outcomes and contents in Agricultural / Biological Sciences not covered by the core curriculum proposed by FEANI program of studies in the above new virtual program are defined in terms of courses, that could be included in the Agricultural Sciences part of the specialisations or as electives

    Agricultural Engineering programmes meeting the FEANI and EurAgEng criteria in Italy

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    The only administrative change which took place in Italian institutions from the status described in the 1st Workshop, in the framework of Bologna process, is the updating of 3+2 years University study programmes. According to the ECTS credit system used in Italian institutions, the total student workload in one year is 60 CFU, which are considered equivalent to 60 ECTS; each CFU represents 25 hours of learning, both as aided learning and as individual studies. The 1st cycle degree study programme (\u201cLaurea\u201d) consists of 180 ECTS, while the 2nd cycle one (\u201cLaurea Magistrale\u201d) is constituted by 120 ECTS. No adjustment, alteration or difference concerning the quality assurance scheme used in Italy happened since the 5th USAEE Workshop. At present the Faculties of Agriculture of the Universities of Molise, Palermo, Sassari and Viterbo offer 1st cycle degree programmes of studies with titles related to Agricultural Engineering. Moreover, nowadays the Universities of Bari, Molise, Sassari and Viterbo offer 2nd cycle Agricultural Engineering degree study programmes. A proposal of virtual 1st and 2nd cycle study programmes, meeting the FEANI and EurAgEng criteria, the Italian cultural requirements and the criteria of the national University system, is shown in terms of course categories and ECTS credits

    Enhancement of the Roman Bridge of Canosa in the Ofanto Valley Rural Landscape

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    The ancient Roman Bridge, 2,000 years old, is located on the old Via Traiana route, three kilometers far from the town of Canosa (Apulia Region), and for many centuries it was the connection between northern and southern part of the Apulia Region along the Adriatic coast. It has an imposing structure stonework, with a donkey back shape, built with five round arches supported by piers sustained by rostrums. During the Second World War, a concrete access way was realized in order to let the British and American army tank pass through the bridge. The “Municipal Plan of the Tratturi” qualifies the area as “sheep trails or path” that preserves the original consistency or that can be at the same renovated. Aim of the research is the requalification of the study area through analyses, plan and restructuring the ancient routes. In this study, the current status of the area is analyzed in detail and the inconsistency of the interventions is highlighted. The project proposal provides for new tourism paths equipped with cycle/pedestrian tracks and small resting and refreshment areas, intermodal exchange car parks and management structures, allowing the creation of a green tourist-cultural route

    Five steps for managing Europe’s forests

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    Near-real time forest change detection using PlanetScope imagery

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    © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. To combat global deforestation, monitoring forest disturbances at sub-annual scales is a key challenge. For this purpose, the new Planetscope nano-satellite constellation is a game changer, with a revisit time of 1 day and a pixel size of 3-m. We present a near-real time forest disturbance alert system based on PlanetScope imagery: the Thresholding Rewards and Penances algorithm (TRP). It produces a new forest change map as soon as a new PlanetScope image is acquired. To calibrate and validate TRP, a reference set was constructed as a complete census of five randomly selected study areas in Tuscany, Italy. We processed 572 PlanetScope images acquired between 1 May 2018 and 5 July 2019. TRP was used to construct forest change maps during the study period for which the final user’s accuracy was 86% and the final producer’s accuracy was 92%. In addition, we estimated the forest change area using an unbiased stratified estimator that can be used with a small sample of reference data. The 95% confidence interval for the sample-based estimate of 56.89 ha included the census-based area estimate of 56.19 ha.s

    Bio-energy retains its mitigation potential under elevated CO2

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    Background If biofuels are to be a viable substitute for fossil fuels, it is essential that they retain their potential to mitigate climate change under future atmospheric conditions. Elevated atmospheric CO2 concentration [CO2] stimulates plant biomass production; however, the beneficial effects of increased production may be offset by higher energy costs in crop management. Methodology/Main findings We maintained full size poplar short rotation coppice (SRC) systems under both current ambient and future elevated [CO2] (550 ppm) and estimated their net energy and greenhouse gas balance. We show that a poplar SRC system is energy efficient and produces more energy than required for coppice management. Even more, elevated [CO2] will increase the net energy production and greenhouse gas balance of a SRC system with 18%. Managing the trees in shorter rotation cycles (i.e. 2 year cycles instead of 3 year cycles) will further enhance the benefits from elevated [CO2] on both the net energy and greenhouse gas balance. Conclusions/significance Adapting coppice management to the future atmospheric [CO2] is necessary to fully benefit from the climate mitigation potential of bio-energy systems. Further, a future increase in potential biomass production due to elevated [CO2] outweighs the increased production costs resulting in a northward extension of the area where SRC is greenhouse gas neutral. Currently, the main part of the European terrestrial carbon sink is found in forest biomass and attributed to harvesting less than the annual growth in wood. Because SRC is intensively managed, with a higher turnover in wood production than conventional forest, northward expansion of SRC is likely to erode the European terrestrial carbon sink
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