1,720,959 research outputs found
Structural design and experimental tests on a model of tensegrity greenhouse prototype
No full textThe aim of this paper is the analysis, proposal and application of a structural tensegrity configuration for greenhouses supporting structures suitable for lightweight covering, based on principles of design coherence, material savings and building durability. By means of the FEM software, Sofistik®, a tensegral greenhouse prototype was modelled and designed in accordance with EN 13031-1:2019. In order to calibrate the results of the FEM analysis, experimental load tests and displacement measurements made with a tensegrity reduced scale model on a tensegrity reduced scale model, created at the Department laboratory of the University of Bari, were compared with the results of the calculation analysis. The displacements of the prototype selected nodes were detected by Target tracking Technology in two load configurations and a control transducer was positioned on the central structural node. The comparison among the displacements of the detected nodes with those resulting from the FEM software calculations, for two different load configurations, show average percentage errors of 7.1% and 12.55%. The results of the T test for the different load configuration point out that the two series of values experimental-ly detected and calculated by the software are not significantly dif-mme ferent. Finally, results in terms of the structural steel weight and maximum stress of the tensegral structure were compared with those of commercial structures, both with vaulted roof and duo-pitched roof, of single span greenhouses having the same covered ground area of the greenhouse prototype. The proposed tensegrity greenhouse prototype showed a 9.6% and 35.2% reduction of the structural steel weight compared to the vaulted roof and to the duo-pitched roof greenhouse respectively. nly
Innovative Tensile Structures for Protected Crop Facilities
Full text linkGreenhouse 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
Tensegrity greenhouse: An innovative covering structural system with low shading
Full text linkBased 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
Polycarbonate laminates thermo-mechanical behaviour under different operating temperatures
No full textThis study deals with tensile tests on rigid polymeric innovative material for greenhouse covering. Specimens of polycarbonate Makrolon ® UV Climate Control blue were analyzed. Tension tests were conducted on bone-shaped samples, according to European standards, and at different temperatures from 20 °C to 80 °C on the basis of the summer temperatures registered by the greenhouses supporting metal structures in contact with the plastic covering. During tensile test the surface temperature of the specimens was measured using infrared technology. Finally, the obtained strain and temperature trend are discussed and an interpretation of the mechanical behaviour of the material is given based on a Griffith like approach
Tensegrity greenhouse: an innovative covering structural system with low shading
No full textBased 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.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
Enhancement of the Roman Bridge of Canosa in the Ofanto Valley Rural Landscape
Full text linkThe 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
Evaluation of wall surface temperatures in green facades
No full textGreen walls can be used to control the building microclimate as passive systems for energy saving. Three vertical walls were built at the University of Bari (Italy). The first wall was covered with Pandorea jasminoides variegated and the second with Rhyncospermum jasminoides; the third wall was kept uncovered as a control. High-definition infrared images were recorded, and several climatic parameters concerning the walls and the ambient conditions were collected during the experimental test. The daylight temperatures observed on the shielded walls during warm days were lower than the respective temperatures of the uncovered wall by up to 9·0°C; the nighttime temperatures observed during cold days were higher than the respective temperatures of the control wall by up to 6·0°C. The effective thermal resistance of the plants was calculated, using experimental data for a whole year; it ranged from 0·07 to 3·61m2 K/W
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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