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Perez R.,Polytechnic University of Catalonia | Puig V.,Polytechnic University of Catalonia | Puig V.,Iri Institute Of Robotica I Informatica Industrial Csic Upc | Pascual J.,Polytechnic University of Catalonia | And 3 more authors.
Control Engineering Practice | Year: 2011

Leaks are present to some extent in all water-distribution systems. This paper proposes a leakage localisation method based on the pressure measurements and pressure sensitivity analysis of nodes in a network. The sensitivity analysis using analytical tools is not a trivial job in a real network because of the huge non-explicit non-linear systems of equations that describe its dynamics. Simulations of the network in the presence and the absence of leakage may provide an approximation of this sensitivity. This matrix is binarised using a threshold independent of the node. The binary matrix is assumed as a signature matrix for leakages. However, there is a trade-off between the resolution of the leakage isolation procedure and the number of available pressure sensors. In order to maximise the isolability with a reasonable number of sensors, an optimal sensor placement methodology, based on genetic algorithms, is also proposed. These methodologies have been applied to the Barcelona Network using PICCOLO simulator. The sensor placement and the leakage detection and localisation methodologies are applied to several district management areas (DMA) in simulation and in reality. © 2011 Elsevier Ltd. Source


Perez R.,Polytechnic University of Catalonia | Puig V.,Polytechnic University of Catalonia | Pascual J.,Polytechnic University of Catalonia | Quevedo J.,Polytechnic University of Catalonia | And 2 more authors.
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2010

Leaks are present to some extent in all water-distribution systems. This paper proposes a leakage localisation method based on the pressure measurements and pressure sensitivity analysis of nodes in a network. The sensitivity analysis using analytical tools is not a trivial job in a real network because the huge non-explicit non-línear systems of equation that describe its dynamics. Simulations of the network in presence and absence of leakage may provide an approximation of this sensitivity. This matrix is binarised using a threshold independent of the node. The binary matrix is assumed as a signature matrix for leakages. However, there is a trade-off between the resolution of the leakage isolation procedure and the number of available pressure sensors. In order to maximise the isolability with a reasonable number of sensors, an optimal sensor placement methodology, based on genetic algorithms, is also proposed. This methodology has been developed for Barcelona Network using Piccolo simulator. The sensor placement and the leakage detection and localization methodologies are applied to district management areas (DMA). Source


Meseguer J.,Water Technological Center | Meseguer J.,Polytechnic University of Catalonia | Puig V.,Polytechnic University of Catalonia | Escobet T.,Polytechnic University of Catalonia
IEEE Transactions on Systems, Man, and Cybernetics Part A:Systems and Humans | Year: 2010

This paper proposes a fault diagnosis method using a timed discrete-event approach based on interval observers that improves the integration of fault detection and isolation tasks. The interface between fault detection and fault isolation considers the activation degree and the occurrence time instant of the diagnostic signals using a combination of several theoretical fault signature matrices that store the knowledge of the relationship between diagnostic signals and faults. The fault isolation module is implemented using a timed discrete-event approach that recognizes the occurrence of a fault by identifying a unique sequence of observable events (fault signals). The states and transitions that characterize such a system can directly be inferred from the relation between fault signals and faults. The proposed fault diagnosis approach has been motivated by the problem of detecting and isolating faults of the Barcelona's urban sewer system limnimeters (level meter sensors). The results obtained in this case study illustrate the benefits of using the proposed approach in comparison with the standard fault detection and isolation approach. © 2010 IEEE. Source


Gibert O.,Polytechnic University of Catalonia | Gibert O.,Water Technological Center | Valderrama C.,Polytechnic University of Catalonia | Peterkova M.,Polytechnic University of Catalonia | And 2 more authors.
Solvent Extraction and Ion Exchange | Year: 2010

Three commercially available sorbents/exchangers (namely CsTreat, ZrP, and S910) were evaluated under column conditions for the extraction of four metals (Cs(I), Rb(I), Li(I), and U(VI)) from a brine rejected by a Seawater Reverse Osmosis plant. From the obtained breakthrough curves and periodic analysis of the influent and effluent, the uptake capacities of the materials were quantified. The fixation of the target metal onto the sorbents was investigated also by SEM-EDX and FTIR-ATR analysis. The results showed that CsTreat displayed a high sorption capacity of Rb(I) and a fairly high sorption capacity of Cs(I), as the resin S910 showed of U(VI), while ZrP proved to be ineffective for the retention of Li(I). © Taylor & Francis Group, LLC. Source


Platikanov S.,CSIC - Institute of Environmental Assessment And Water Research | Garcia V.,Aigues Of Barcelona Agbar Laboratory | Fonseca I.,Water Technological Center | Rullan E.,Water Technological Center | And 2 more authors.
Water Research | Year: 2013

Chemometric analysis was performed on two sets of sensory data obtained from two separate studies. Twenty commercially-available bottled mineral water samples (from the first study) and twenty-five drinking tap and bottled water samples (from the second study) were blind tasted by trained panelists. The panelists expressed their overall liking of the water samples by rating from 0 (worst flavor) to 10 (best flavor). The mean overall score was compared to the physicochemical properties of the samples. Thirteen different physicochemical parameters were considered in both studies and, additionally, residual chlorine levels were assessed in the second study. Principal component analysis performed on the physicochemical parameters and the panelists' mean scores generated models that explain most of the total data variance. Moreover, partial least squares regression of the panelists' sensory evaluations of the physicochemical data helped elucidate the main features underlying the panelists' ratings. The preferred bottled and tap water samples were associated with moderate (relatively to the parameters mean values) contents of total dissolved solids and with relatively high concentrations of HCO3-, SO42-, Ca2+ and Mg2+ as well as with relatively high pH values. High concentrations of Na+, K+ and Cl- were scored low by many of the panelists, while residual chlorine did not affect the ratings, but did enable the panel to distinguish between bottled mineral water and tap water samples. © 2012 Elsevier Ltd. Source

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