87 research outputs found
Alcune proprietà algebriche dei problemi ausiliari: Un contributo alla teoria dei problemi
No full text
Aligning the Astronomical Observations of the Maria Valtorta writings with the birth date of the Virgin Mary as given in Medjugorje
No full textIn this short paper we analyse the writings of Maria Valtorta that relate to the Birth of the Virgin Mary and extract descriptions relating to the astronomical and environmental features which the author allegedly witnesses. Using planetary software we attempt to align these observations with August 5th 16BC; the date given for the Birth of the Virgin Mary by the alleged Medjugorje visionaries. Using data from the Valtorta vision relating to both the unusual weather conditions and the position of a rainbow over Mount Hermon; we unexpectedly found that the bearing and elevation of the Moon as observed from Nazareth on the Medjugorje date could indeed create the conditions suitable for an observable Lunar Rainbow rising from the peak of Mount Hermon. We found at no time in August of 16BC could the Sun have been responsible for the Valtorta rainbow
Scrittori-fotografi in Sicilia tra la fine dell'Ottocento e i primi del Novecento
No full text• L’immagine della Sicilia tra Ottocento e Novecento è, come ogni altra immagine alle soglie della contemporaneità, un’immagine fotografica.
• Questa immagine non la si deve solo ai fotografi di professione, ma anche agli scrittori. I due livelli di narrazione, quello visivo e quello letterario, si avvicendano e si intrecciano in modo importante e assai articolato.
• Tre scrittori-fotografi come Luigi Capuana, Giovanni Verga e Federico De Roberto hanno costruito con la fotografia e con la letteratura un’immagine della Sicilia che ci coinvolge ancora oggi
Monitoring Cable current and Laying Environment Parameters for Assessing the Aging Rate of MV Cable Joint Insulation
No full textJoints are critical components of MV cable distribution networks and the aging rate of their insulation is particularly sensitive to temperature due to loading current and laying environment parameters. This makes it very useful to monitor the load current and laying environment parameters (humidity, pressure and temperature) of joints, so as to single out conditions that might accelerate joint insulation aging rate critically. This paper illustrates the installation of humidity, pressure, current and temperature sensors - in a partnership between e-distribuzione (the main DSO in Italy) and the University of Bologna - to assess the aging rate of cable joint insulation in underground distribution network
Ground Resistance of Buried Metallic Parts in Urban Areas: an Extensive Measurement Campaign
No full textIn urban and industrial areas, a relevant presence of buried metallic objects (e.g., gas and water pipes, etc.) can be detected. Usually, these elements are imagined as widespread meshed metallic grids in a good contact with the soil. In the last years, an arising interest on their role in the identification of a global earthing system has been expressed by the scientific community. Unfortunately, the geometrical and electrical properties of this kind of buried metallic parts cannot be provided by any documentations. This is mostly due to the fact that no trustworthy schemes are provided, as the management of these metallic parts is responsibility of different companies, which have installed them during several years. In order to characterize the buried metallic elements with reference to the electrical safety issue, the main quantity of interest is their resistance to earth. With this aim, a field measurement campaign was organized and the resistance to earth of more than 800 metallic objects has been evaluated through a simplified measurement protocol. In this paper, the measurement protocol, the setup, the results, and their analysis are reported
DSOs and Active Demand: ADDRESS Project outcomes and perspectives
No full textADDRESS (“Active Distribution networks with full integration of Demand and distributed energy RESourceS”) is a 5-year large-scale R&D project launched in June 2008 and ended in May 2013, receiving funding from the European Community's Seventh Framework Program (FP7/2007-2013) under grant agreement n° 207643.
This project aims to develop a comprehensive commercial and technical framework for the development of “Active Demand” and the market-based exploitation of its benefits. In ADDRESS, “Active Demand” (AD) means the active participation of domestic and small commercial consumers in the electricity markets and in the provision of services to the other electricity system participants.
The paper deals with the architecture and the algorithms developed as well as the validation field test and the AD perspectives being, at least from the technical point of view, a reality for the smart grid of the (next) future
Ground Fault Temporary Overvoltages in MV Networks: Evaluation and Experimental Tests
No full textSingle-phase-to-ground faults may cause substantial temporary overvoltages (TOVs) in large radial medium-voltage networks with isolated neutral, even over 3-p.u. phase to ground. Resonant neutral earthing limits these overvoltages to 1.8 p.u. but credible earthing apparatus failures might trigger TOVs up to 2.4 p.u. This paper presents the ground fault study of an Italian 20-kV ENEL Distribuzione network. Analytical evaluations in a wide parametric range of neutral earthing arrangements, include isolated neutral and ENEL resonant earthing with parallel resistance, as evidence of 2.4-p.u. TOVs with isolated neutral, 1.8 p.u. with resonant earthing, and more than 2.0 p.u. with partial compensation. Recordings of ground faults staged in the same network are presented, showing excellent agreement between analytical predictions and experimental test. The tests confirm TOVs of more than 2.3 p.u. with isolated neutral, sometimes evolving into cross-country faults (possibly explaining unforeseen cable fault rates), and the effectiveness of the ENEL neutral earthing practices in suppressing these TOVs
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