Novel LoadProGen procedure for micro-grid design in emerging country scenarios: Application to energy storage sizing

This paper is devoted to describe the development, implementation and application of a novel procedure to properly design the electrification process in rural areas of Emerging Countries (EC). The procedure exploits a bottom-up approach, i.e. target applications are related to micro-grids devoted to satisfy the electrical needs of small communities. The procedure starts from microscopic data (i.e. single electric appliances) to effectively catch the customer needs (i.e. bottom) and it matches them with the available energy sources in the target area. In particular, a tool named LoadProGen developed by the Energy4Growing research group of Politecnico di Milano, is presented: the mathematical approach proposed is detailed and a real field case study relevant to a micro-grid deployed in Tanzania is provided. The tool is based on the gathering of information about the target area, i.e. to get information from interview and field audit, and on a stochastic approach to build up realistic estimation of the electric load profile of the considered uses. The energy needs forecast (cfr. load profile) is then adopted in a second procedure devoted to design a micro-grid capable to properly feed the loads. In this work, for sake of exemplification, this latter is supposed to be a photovoltaic based micro-grid integrated with an electrochemical storage

Anthropogenic sinkholes in the Marsala area (western Sicily) linked to underground quarries

Marsala territory (western Sicily) is characterized by the presence of a Lower Pleistocene (Calabrian) calcarenite succession (Marsala Calcarenite Fm). It can be divided into three lithofacies that show the regressive evolution of the depositional system: a) coarse to fine yellow bio- and lithoclastic calcarenites, b) sands, and c) gray sandy clays. At least 80 m-thick, this succession gently dips (5-10) towards the south and the south-west. At some locations the Marsala Calcarenite is covered by Middle and Upper Pleistocene marine terraced deposits. Since the Roman period, due to the great abundance of calcarenite rocks, and to the facility of extraction, the Marsala area has been characterized by a high number of quarries for the extraction of this building materials. Many of them were excavated underground, at depth varying from a few meters to about 25 m, and are arranged in one or two levels, following the galleries and pillars excavation technique. With time, the underground quarries have been progressively abandoned for the decay of the physical and mechanical properties of the calcarenite rock mass, the interaction with the groundwater, the high costs of extraction, and the dangers and difficulties encountered in working underground. Since the 1960’s the quarries have been affected by instability processes, visible through collapses and deformations of vaults and pillars. These phenomena often propagate upward reaching the topographic surface and forming sinkholes which affect and severely damage the built-up area. In particular, two case studies of sinkholes related to different underground quarries will be analyzed in this paper. The aim is to provide a description of the most significant processes and factors responsible of the instability processes based on field surveys, as well as to understand the generation mechanisms of these anthropogenic sinkholes by means of numerical modeling, based on rock laboratory testing data, that represents in these cases a remarkable tool for the investigation of the cause-effect relationships, as already performed in other areas of Italy

Good prognosis for pericarditis with and without myocardial involvement: Results from a multicenter, prospective cohort study

Background The natural history of myopericarditis/perimyocarditis is poorly known, and recently published studies have presented contrasting data on their outcomes. The aim of the present article is to assess the prognosis of myopericarditis/perimyocarditis in a multicenter, prospective cohort study. Methods and Results A total of 486 patients (median age, 39 years; range, 18-83 years; 300 men) with acute pericarditis or a myopericardial inflammatory syndrome (myopericarditis/perimyocarditis; 85% idiopathic, 11% connective tissue disease or inflammatory bowel disease, 5% infective) were prospectively evaluated from January 2007 to December 2011. The diagnosis of acute pericarditis was based on the presence of 2 of 4 clinical criteria (chest pain, pericardial rubs, widespread ST-segment elevation or PR depression, and new or worsening pericardial effusion). Myopericardial inflammatory involvement was suspected with atypical ECG changes for pericarditis, arrhythmias, and cardiac troponin elevation or new or worsening ventricular dysfunction on echocardiography and confirmed by cardiac magnetic resonance. After a median follow-up of 36 months, normalization of left ventricular function was achieved in >90% of patients with myopericarditis/perimyocarditis. No deaths were recorded, as well as evolution to heart failure or symptomatic left ventricular dysfunction. Recurrences (mainly as recurrent pericarditis) were the most common complication during follow-up and were recorded more frequently in patients with acute pericarditis (32%) than in those with myopericarditis (11%) or perimyocarditis (12%; P<0.001). Troponin elevation was not associated with an increase in complications. Conclusions The outcome of myopericardial inflammatory syndromes is good. Unlike acute coronary syndromes, troponin elevation is not a negative prognostic marker in this setting

L’ultimo sprofondamento a Marsala: l’evento del 21 novembre 2013

The Marsala area, at the western end of Sicily, has been historically interested by quarry activities, both at surface and underground. The carved rocks are Lower Pleistocene calcarenites, defined as “Calcarenite di Marsala” and referred to the Marsala syntheme. The subterranean quarries, now abandoned, show increasing instability signs becoming in time a risk factor for several causes, among which: a) breakdowns due to poor (weak) strength of rock and to large size of voids; b) progressive weathering of rock; c) effects of the discontinuities in the rock mass with the pillars and/or walls of the underground quarries. These factors contributed to enlargement of the subterranean voids and to their upward propagation, thus triggering several sinkholes. The fast urbanization of the city masked many subterranean quarries causing the loss of memory of their location.In the last decades, numerous sinkholes occurred both in urban sectors and in areas designated for agricultural use, creating extensive damage to buildings and infrastructures.The latest sinkhole episode occurred in the Amabilina area, at the eastern suburbs of Marsala. The depression shows an elliptical perimeter (100×70 m) and a depth of at least 15 m.At the bottom, some rooms up to 5 m high of an underground quarry are visible. From the evidences collected a few days after the event, it was possible to reconstruct the time sequence in the formation of the sinkhole. The collapse started due to the propagation of voids and a first failure of some pillars, and was subsequently followed by a second event, which caused a widening of the depression, due to the redistribution of the stress resulting after early failures