1,720,982 research outputs found
Studio sperimentale per la determinazione delle leggi di scala spaziale e temporale di dati di consumo idrico istantaneo residenziale
No full textIl consumo idrico residenziale, nell’ambito dei sistemi di distribuzione urbana, rappresenta indubbiamente la componente predominante, pur nella variabilità propria delle differenti realtà insediative. Conseguentemente, l’analisi delle caratteristiche di questa componente risulta di estremo interesse nella formulazione di modelli di simulazione della domanda istantanea che costituiscono la sollecitazione idraulica, di tipo parzialmente aleatorio, dei sistemi acquedottistici. Il consumo idrico residenziale può essere schematizzato come un processo stocastico caratterizzato da un limitato numero di parametri, variabili periodicamente nel tempo. Il processo manifesta peraltro, a differenti scale di aggregazione spaziale e temporale, peculiari caratteristiche non lineari, con specifico riguardo ai volumi complessivi erogati ed ai fattori di contemporaneità d’uso delle singole utenze. L’analisi di una campagna pluriennale di monitoraggio dei consumi idrici istantanei di 82 utenze residenziali di tipologia omogenea, ha costituito lo spunto per una complessiva rivisitazione dell’approccio tradizionale a tale problematica. In particolare una prima rielaborazione riguarda la stima delle caratteristiche medie del consumo misurato e la sua variabilità a differenti aggregazioni spaziali e temporali. Vengono inoltre presentati i risultati ottenuti dalla elaborazione di differenti aggregazioni spaziali dei dati di consumo di singole utenze, nonché le potenzialità di un tale approccio alla formulazione dei problemi di dimensionamento, simulazione, controllo in tempo reale e ricerca perdite dei sistemi acquedottistici complessi
Sviluppo di un sistema per la riduzione delle perdite idriche attraverso il controllo della pressione
No full text
APPROCCIO MULTIOBIETTIVO PER IL POSIZIONAMENTO E LA REGOLAZIONE DELLE VALVOLE DI CONTROLLO DELLA PRESSIONE NELLE RETI DI DISTRIBUZIONE IDRICA
No full textThe paper focuses on the problem of reducing leakages in water distribution systems through dynamic heads control with pressure reduction valves. A multi-objective optimization approach is followed for the location of the valves and for their setting
Multi objective approach for leakage reduction in water distribution systems
No full textThis paper faces the problem of reducing leakages in water distribution systems (WDS) through dynamic heads control with pressure reduction valves (PRV). To achieve this aim a multi-objective optimization approach is followed for the location of control valves and for their setting during different working conditions. In particular, the objectives to be achieved are: 1) to minimize the leakages over all of the network, 2) to minimize the investment costs for the control devices. The objectives must be satisfied considering the variability of the nodal water demand. For a more realistic simulation of the WDS performance the implementation of a fully pressure-dependent leakage specification is required. The multi-objective optimization problem is tackled using a MOGA (Multi-Objective Genetic Algorithm) with a Pareto based approach. The hydraulic modelling of the network is performed with the software EPANET2
Estimation of leakages in water distribution systems with measurements at few nodes.
No full textLeakages in urban water networks can be a very high percentage of the supplied water. The lost volume represents an economic damage not only for the cost of water pumping and treatment, but even because it makes necessary investments into systems capacity expansion or in searching for other water sources.
In most cases of Water Distribution Systems (WDS) the most relevant percentage of lost water can be considered as the sum of small leakages distributed all over the network. In order to reduce this lost volume it may be advisable to plan medium-long term rehabilitation policies of the network combined with suitable management policies for controlling pressure heads in the system. Pressure regulation can be achieved by means of pressure reduction valves (PRV) remotely controlled, whose purpose is to decrease excessive pressures, ensuring the service conditions.
The control of the PRVs is generally performed by mean of a hydraulic simulator of the network able to model as realistically as possible, both the geometry of the network and the nodal discharges.
For a more realistic simulation of the WDS performance, the implementation of a fully pressure-dependent leakage specification is required. In the work, in order to treat water losses as pressure dependent quantities, the calibration of the WDS simulation model is performed concentrating leaks at the nodes and considering their flow as a function only of the local pressure. The estimation of the calibration coefficients is carried out solving an optimization problem with Genetic Algorithms (GA) coupled with the hydraulic model of the network.
In order to obtain more realistic values for the nodal demand and water consumption discharges, it is advisable to base this calibration on the largest possible set of pressure and discharge measurements all over the network. Unfortunately measurements in WDS are usually carried out only at few nodes with high level of users aggregation. To overcome this problem the spatial interpolation of nodal pressures is performed with a geostatistical technique that feeds the calibration procedure with pressure heads at each node of the network
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
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