1,785 research outputs found
Procedimento per la curvatura di tubi, barre, profilati e analoghi semilavorati, e relativo dispositivo
No full textIl procedimento comprende le fasi di spingere il semilavorato (10) lungo una direzione assiale (X) fra un utensile di curvatura mobile (16) e un controutensile fisso (12) e, mentre il semilavorato (10) viene fatto avanzare, spostare l'utensile di curvatura (16) da una posizione neutra, in cui il semilavorato (10) non viene curvato, a una posizione di lavoro, in cui il tubo semilavorato (10) viene curvato al raggio medio di curvatura desiderato, la posizione di lavoro essendo ruotata rispetto alla posizione neutra di un dato angolo di rotazione (α) funzione del raggio medio di curvatura desiderato. Secondo l'invenzione, il
procedimento comprende inoltre l'operazione di spingere il semilavorato (10) fra una coppia di pattini (20, 22) a monte dell'utensile di curvatura (16) in modo da favorire la
deformazione del semilavorato (10), e la fase di spostamento dell'utensile di curvatura (16) dalla posizione neutra alla posizione di lavoro viene eseguita controllando almeno due
gradi di libertà di spostamento dell'utensile di curvatura (16) nel piano (XY) individuato dalla direzione assiale (X) e da una direzione trasversale (Y) perpendicolare alla direzione
assiale (X). Grazie all'iniziale deformazione di compressione assiale e radiale del semilavorato (10) per effetto del passaggio fra i pattini (20, 22), la successiva fase di curvatura da parte dell'utensile di curvatura (16) risulta agevolata e permette l'ottenimento di raggi medi di curvatura significativamente inferiori di quelli minimi sinora ottenibili con i tradizionali procedimenti di curvatura a raggio variabile
Dynamic Characterization of a High-Altitude Balloon During a Flight Campaign for the Detection of ISM Radio Background in the Stratosphere
No full textSounding balloons, available at very low cost from commercial vendors and operable with minimal training, have an excellent potential as testing platforms in the near-space environment. The work here reported was motivated by the need to perform an experimental assessment of the RF background present in the ISM (Industrial, Scientific, and Medical) bands, namely 868 MHz (UHF) and 2.4 GHz (S-Band), simulating the operational environment of a LEO constellation for IoT telecommunications. To this end, five balloons were flown with a dedicated RF payload. Along with the radio measurements, the flights provided a convenient opportunity to collect data on the dynamic behaviour of the payload gondola. We report on the system design and the operational phase of the mission, and discuss the data collected throughout the successful flight campaign. As a result, a preliminary understanding of the gondola dynamics has been gained, including both linear accelerations and attitude oscillations. It is also concluded that the two ISM band considered are actually suitable for IoT ground-to-LEO links
CARTE E CARTOGRAFI SULL’APPENNINO LIGURE-EMILIANO. LA STRADA DI CENTO CROCI NEI PROGETTI DI MATTEO E PANFILIO VINZONI E DI PIERRE-PAUL DE COTTE
No full textIn the second half of the eighteenth century the Duchy of Parma and the Republic of Genoa agree to build a carriageway that, through the pass of Cento Croci on the Apennines, would connect the Ligurian Sea to the Adriatic through the Po river. The project is carried out only at the end of the nineteenth century, but committed for a long time the engineers-cartographers of the two States, leaving us a large number of cartographic works: today interesting sources for the landscape studies related to the transformations to the eighteenth-century “road revolution”. In this short article I want to focus in particular on the works of Matteo and Panfilio Vinzoni and Pier-Paul De Cotte, key-figures in the history of cartography and for the local history, between Liguria and Emilia
Flight Campaign Results and Prospects of High-Altitude Balloons for Low Cost Spacecraft Technology Testing
No full textZero-pressure and super-pressure stratospheric balloons are widely used, high performance platforms for scientific research and technology development. The complexity and cost of such platforms and of the associated ground infrastructure is such that they are typically operated by space agencies or large research institutions only. This paper deals with a much simpler and affordable variant of the High-Altitude Balloon (HAB) technology, i.e. the so called sounding balloons, which are nowadays available at very low cost from commercial vendors and freely operable. Although with reduced performance in terms of flight duration and payload mass, sounding balloons have an excellent potential as testing platforms for flight hardware in the near-space environment.
The main goal of the work here reported was to create a low-cost near-space platform for experimenting and testing on telecommunication hardware in the ISM (Industrial, Scientific, and Medical) bands, namely 900 MHz (UHF) and 2.4 GHz (S-Band). In particular, the goal was to assess the electromagnetic noise in the ISM bands simulating the operational environment of a LEO constellation dedicated to IoT telecommunications. To this end, we set up a system based on a commercial, low-cost HAB. We report the design phase, the operative mission phase, and finally discuss the data collected throughout a fully successful campaign of five launches
An ancient pilgrimage route and its changes over time: the “Strada della Cisa”. A proposal for development of cultural heritage and landscape
No full textThe International Conference the European Pilgrimage Routes for promoting sustainable and quality tourism in rural areas took place December 4 to 6, 2014 in Firenze (Italy) and was organized by the Department of Agricultural, Food and Forestry Systems – University of Florence in collaboration with the Tuscany Region, the Department for Life Quality Studies and Department of Agricultural Sciences – University of Bologna, the Italian Association of Agricultural Engineering and the European Association of the Francigena Way. The Conference involving 150 experts from 18 countries and was divided into five areas of discussion: conservation and evolution of the landscape along the routes; life quality and social impact; tourism and local development; sustainability in the rural areas; tools and methods for building a tourist attraction
First Flights of a New Test Facility for Solar Cell Characterization in the Stratosphere
No full textECAPS (Experimental Characterization of Advanced Photovoltaics in the Stratosphere) is a new solar cell test facility developed to allow accurate characterization of photovoltaics in the near-space environment. The system is design to fly on both large zero-pressure balloons and on small sounding (weather) balloons, providing a low cost, quick access alternative route to the stratospheric AM0 environment. In 2022, ECAPS flew on a sounding balloon flight from central Italy and on the SOLAR mission by CNES (HEMERA programme) from Timmins, Canada, successfully testing several last generation and experimental solar cells and demonstrating the viability of the system for cell characterization and calibration. Further flights are scheduled for 2023 from both locations. In this paper, the key concepts of the facility design and a summary of the flight results are reported
A Custom Radiosonde Design for Environmental Measurements Over Maritime Areas
No full textRadiosounding is the process of collecting measurements of atmospheric parameters (pressure, temperature, relative humidity) over a range of altitudes above ground. A sensor package is attached to a lighter-than-air balloon and released to fly over the area of interest. Measurements are relayed to the ground by radio. This technique provides the basic, essential data used for weather forecast worldwide. The work here reported was aimed at designing, building and testing a custom radiosonde system, including the sensor package, the ground station and the lifting balloon infrastructure, to perform environmental sounding over maritime areas. The chosen architecture is based on a simple centralized controller architecture with the low data rate radio link provided by a LoRa transceiver. The paper presents the design of the system and the results of laboratory and ground tests. Very satisfactory performance has been demonstrated, including long range transmission in realistic conditions
Science, Technology and Systems Engineering Educational Activities with Stratospheric Balloons
No full textThe Space Systems Laboratory of the University of Pisa started in 2021 a student-oriented high altitude ballooning programme intended to provide an opportunity for hands-on experience in support of scientific and technical courses. Following a call for proposal open to all students across all study areas, three experiments were selected featuring multi-disciplinary teams. The programme provides mentoring on scientific, technical and management issues, financial support and assistance with integration and launch on a sounding balloon platform. The goal is to fly the experiments in the stratosphere, retrieve them after landing and process the results; by doing so, the students experience all phases of a scientific mission project, from conceptual design to realization, operations and post-flight analysis. This paper summarizes the features of the programme’s first edition
Validation Flight Experiment for a Sounding Balloon Photovoltaic-based Attitude Determination System
No full textSounding balloons have proven to be a very effective low-cost method to bring scientific and commercial payloads to the near-space environment. In the frame of our ongoing effort towards the development of a small stratospheric platform with autonomous flying capabilities, we have undertaken the design and manufacture of a flight experiment to verify the possibility to perform onboard attitude determination using the solar cell power output measurements to complement the inertial sensor. The system is based on six low-cost terrestrial solar cells placed on the sides of a box-shaped gondola, lifted to about 34 km altitude by a weather balloon. We describe the system architecture, the results of the first experimental flight and the post-landing attitude reconstruction
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