Le Community Enterprises in Gran Bretagna: imprese sociali come modello di rigenerazione

Nel dibattito italiano, sia accademico che giornalistico, le questioni che riguardano la riduzione della spesa pubblica, la dismissione del patrimonio pubblico, la rigenerazione urbana delle periferie, la partecipazione ed il coinvolgimento delle comunità nei processi di pianificazione, rappresentano temi di crescente rilevanza. In risposta a queste problematiche, la Gran Bretagna - paese in cui da sempre la pianificazione del territorio ha una dimensione multidisciplinare - ha riconosciuto il ruolo di alcune imprese sociali definite community enterprises. Queste organizzazioni sono nate da processi spontanei e distinti, in uno stretto dualismo tra l’azione locale e gli indirizzi delle politiche nazionali, affermandosi come strumento di rigenerazione urbana sostenibile. L’efficacia d’azione delle community enterprises consiste nella promozione di processi di capacity bulding, che pongono al centro della rigenerazione le comunità con le proprie risorse, favorendone l’attitudine ad operare per il proprio welfare e proponendo formule redistributive di sviluppo urbano. La recente trasformazione culturale e politica nota come “from the Big State to Big Society” ha riconosciuto la capacità d’azione di queste imprese, ma ne ha allo stesso tempo messo in discussione il ruolo, individuando come maggior limite delle stesse la dipendenza dal sostegno pubblico quale elemento necessario a garantirne lo sviluppo e la loro azione sui territori. In questo contributo1 si propone una lettura dell’evoluzione delle politiche urbane del Regno Unito e un inquadramento generale delle diverse tipologie di community enterprises, con particolare riferimento ai Community Development Trust. Nello specifico è stato approfondito il caso del Westway Development Trust di Londra, il suo potenziale di sviluppo e i risultati raggiunti in termini di attività e capacità economiche

Hybrid Evolutionary Optimization/Heuristic Technique for Water System Expansion and Operation

This paper presents a methodological solution to The Battle of Background Leakage Assessment for Water Networks (BBLAWN) competition. The methodology employs two constrained multiple-objective optimization problems and is implemented in the context of a software application for the generic hydraulic optimization and benchmarking of Water Distribution System (WDS) problems. The objectives are the combined infrastructure and operational costs and system-wide leakage, both to be minimized. In order to accelerate the evaluation of potential solutions, a distributed computing approach permits multiple EPANET solutions to be evaluated in parallel. A pressure-driven demand extension to EPANET assists the optimization in accurately ranking near-feasible solutions and to dynamically allocate leakage demand to nodes. Pressure Reducing Valves (PRVs) have been located in two ways: a priori, with respect to the optimization analysis and a posteriori after the infrastructure optimization to reduce excess pressure and pipe leakage. The latter demonstrates better overall fitness, leading to optimal configurations dominating those obtained with the former. Several temporal resolutions for PRV settings have been evaluated to contrast the optimal solutions with the computational effort required

Pressure-Driven Demand Extension for EPANET (EPANETpdd)

addresses: Mark Morley, University of Exeter, Centre for Water Systems, North Park Road, Exeter, Devon, EX4 4QF, United Kingdom; Carla Tricarico, Università degli Studi di Cassino e del Lazio Meridionale, Dipartimento di Ingegneria Civile e Meccanica, via di Biasio, 43, Cassino, Lazio, ItalyIntroduction Predominantly, Demand-Driven hydraulic simulators such as EPANET used in optimization processes are configured to deliver water even when there is insufficient pressure to do so – Demand-Driven network solver (as EPANET – Rossman, 2000). In the analysis of structurally inadequate systems, however, recent studies [Germanopoulos, 1985, Hayuti & Burrows, 2004, Soares et al., 2003], have highlighted limitations related to the use of such demand-driven solvers. Initially, the sole requirement for the PDD extension was for it to be able to determine more accurately the non-revenue water unsupplied in a pressure-deficient network in order to better estimate the network’s Economic Level of Reliability [Tricarico et al., 2006]. A logical extension of that work required that the PDD simulator should also be able to operate in an EPS mode. As well as EPS, the application of the simulator to the Neptune project introduced two further requirements. PD demand nodes need to be able to exist in parallel with EPANET’s conventional emitters and the ability to specify emitter exponents on an individual rather than global basis. This functionality is required to simulate bursts in networks: PDD nodes will be used to observe the effects on demand nodes whilst EPANET’s standard emitters will be used to simulate unconstrained bursts, which will be represented by different emitter characteristics.University of Exeter, Centre for Water System

Centrifuge modelling of flexible retaining walls subjected to dynamic loading

This paper outlines the results of an experimental program carried out on centrifuge models of cantilevered and propped retaining walls embedded in saturated sand. The main aim of the paper is to investigate the dynamic response of these structures when the foundation soil is saturated by measuring the accelerations and pore pressures in the soil, displacements and bending moment of the walls. A comparison among tests with different geometrical configurations and relative density of the soil is presented. The centrifuge models were subjected to dynamic loading in the form of sinusoidal accelerations applied at the base of the models. This paper also presents data from pressure sensors used to measure total earth pressure on the walls. Furthermore, these results are compared with previous dynamic centrifuge tests on flexible retaining walls in dry sand.Consorzio interuniversitario (ReLUIS project), European Union (SERIES project)This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.soildyn.2016.06.01