Extending EPANET capabilities with Add-In Tools

[EN] EPANET is probably the most widespread model for water distribution network (WDN). More than twenty years after its appearance, it has become a global reference both for hydraulic and quality analysis of water networks. In 2000, EPANET 2 appears, which includes as most important computational feature a new Toolkit. This toolkit was a library of functions allowing the modification of network data and reading results without access to the appropriate files. Over time, the use of this library has been the communication protocol for every application developers who use the method propose by Todini and Pilati to analyze the behavior of WDN. This library also provides interface tools that allow the execution of a simulation from an external application, as long as the network characteristics had been previously defined. This paper presents a change in the original EPANET model, including a new menu in the graphical user interface (GUI). This menu allows users to set up a personal collection of Add-In tools, which use both project data and simulation results. These tools can be customized and allows to extend the analysis capability of EPANET. All of them can access EPANET functions through the Toolkit and were developed by the authors during the Spanish translation of EPANET, taking into account the homologous Add-in tools developed for SWMM model. As an example of the operation and capabilities of this new menu, several applications integrated as EPANET add-in tools are presented. These tools perform tasks such as importing data network from both CAD and GIS systems, the design of WDNs using genetic algorithms, automatic assignment of initial water quality to network nodes; the skeletonization of a network or optimization of pumping schedule in the network in order to achieve a minimum energy cost.Iglesias Rey, PL.; Martínez-Solano, FJ.; Ribelles-Aguilar, J. (2017). Extending EPANET capabilities with Add-In Tools. Procedia Engineering. 186:626-634. doi:10.1016/j.proeng.2017.03.279S62663418

Characterization of cucumber mosaic virus isolated from yam (Dioscorea spp.) in West Africa

Millions of people in the West African sub-region depend on yam for food and income. In 2008, cucumber mosaic virus (CMV), one of the most economically important plant viruses was detected in yam fields in Ghana, Benin and Togo, three of the five topmost yam producing countries in the world. Some strains of CMV are reportedly more virulent than others thus the need to characterise the strain isolated from yam. Sap inoculation of the yam strain induced systemic mosaic on Cucumis sativus and systemic chlorosis, necrotic lesions and leaf distortion on Nicotiana glutinosa. Sequence analysis of the 3' end of the coat protein gene and C-terminal noncoding region revealed 98 to 99, 93 to 98 and 78 to 79% nucleotide homology with members of the subgroups IA, IB and II, respectively. This analysis further revealed the absence of the EcoR1 restriction site characteristic of subgroup II strains and the presence of 15 nucleotide deletions dispersed along the C-terminal noncoding region of subgroup IA strains. At the amino acid level, the virus had 99 to 100% homology with subgroup I strains and 89% homology with subgroup II strains. Phylogenetic analysis of the amino acid confirms that the yam strain of CMV belongs to subgroup I while nucleotide sequence phylogeny confirms its placement in subgroup IA

Efficiency of evolutionary algorithms in water network pipe sizing

© 2015, Springer Science+Business Media Dordrecht. The pipe sizing of water networks via evolutionary algorithms is of great interest because it allows the selection of alternative economical solutions that meet a set of design requirements. However, available evolutionary methods are numerous, and methodologies to compare the performance of these methods beyond obtaining a minimal solution for a given problem are currently lacking. A methodology to compare algorithms based on an efficiency rate (E) is presented here and applied to the pipe-sizing problem of four medium-sized benchmark networks (Hanoi, New York Tunnel, GoYang and R-9 Joao Pessoa). E numerically determines the performance of a given algorithm while also considering the quality of the obtained solution and the required computational effort. From the wide range of available evolutionary algorithms, four algorithms were selected to implement the methodology: a PseudoGenetic Algorithm (PGA), Particle Swarm Optimization (PSO), a Harmony Search and a modified Shuffled Frog Leaping Algorithm (SFLA). After more than 500,000 simulations, a statistical analysis was performed based on the specific parameters each algorithm requires to operate, and finally, E was analyzed for each network and algorithm. The efficiency measure indicated that PGA is the most efficient algorithm for problems of greater complexity and that HS is the most efficient algorithm for less complex problems. However, the main contribution of this work is that the proposed efficiency ratio provides a neutral strategy to compare optimization algorithms and may be useful in the future to select the most appropriate algorithm for different types of optimization problems

BBLAWN: A combined use of best management practices and an optimization model based on a pseudo-genetic algorithm

[EN] The paper presents a solution to the problem of the Battle of Background Leakage Assessment for Water Networks (BBLAWN) using a methodology that combines the use of Best Management Practices (BMPs) and an optimization model based on a Pseudo- Genetic Algorithm (PGA) as described in [1]. In a first stage, an analysis of marginal costs of pipes whose replacement would be potentially recommended was performed. Next, a network topological analysis to study the pipes that could potentially be closed in order to facilitate pressure control was done. Furthermore, a methodology for studying branched areas was also developed, determining possible location for pressure reducing valves (PRV). A significant reduction in the number of decision variables was obtained and a specific optimization model was developed.This work was supported by the project DPI2009-13674 (OPERAGUA) of the Dirección General de Investigación y Gestión del Plan Nacional de I + D + I del Ministerio de Ciencia e Innovación, Spain.Iglesias Rey, PL.; Martínez-Solano, FJ.; Mora Melia, D.; Martinez Solano, PD. (2014). BBLAWN: A combined use of best management practices and an optimization model based on a pseudo-genetic algorithm. Procedia Engineering. 89:29-36. doi:10.1016/j.proeng.2014.11.156S29368

Sensitivity parameters during the emptying maneuvers in water pipelines

[EN] Emptying pipelines can be critical in many water pipelines because subatmospheric pressure troughs are reached due to the expansion of entrapped air, which could cause considerable damage to the system depending on both installation conditions and stiffness pipe. This paper shows the sensitivity analysis for the mathematical model proposed by the authors, where the main hydraulic and thermodynamic parameters are analyzed (internal pipe diameter, friction factor, pipe slope, polytropic coefficient, air valve diameter, air pocket size and time maneuvering of the drain valve). Two cases were analyzed: (i) a pipe with the upstream end closed, and (ii) a pipe with an air valve installed in the upstream end. The results show that in the Case No.1, pipe slope, polytropic coefficient and air pocket size parameters are very sensitive on the subatmospheric pressure troughs, and on the other hand in the Case No. 2, the majority of parameters are very sensitive during the emptying process.[ES] El proceso de vaciado en conducciones de agua genera depresiones por la expansión del aire en el interior de las tuberías y esto podría causar el colapso del sistema dependiendo de las condiciones de instalación y de la rigidez de la conducción. En este artículo se presenta el análisis de sensibilidad del modelo matemático desarrollado por los autores, analizando los principales parámetros hidráulicos y termodinámicos que intervienen en este proceso tales como: diámetro interior de la tubería, factor de fricción, pendiente longitudinal de la tubería, coeficiente politrópico, diámetro de la ventosa, tamaño de la bolsa de aire y tiempo de apertura. Este análisis se realizó para dos casos posibles: Caso No. 1, tubería con el extremo aguas arriba cerrado; y Caso No. 2, tubería con una ventosa instalada en el extremo aguas arriba. Los resultados muestran que para el Caso No. 1 los parámetros que más inciden en las depresiones son la pendiente longitudinal de la tubería, el coeficiente politrópico y el tamaño de la bolsa de aire; mientras que para el Caso No. 2, la mayoría de los parámetros influyen significativamente durante el proceso de vaciado.Los autores agradecen la financiación del estudiante de doctorado Óscar E. Coronado-Hernández, realizada por la Fundación Centro de Estudios Interdisciplinarios Básicos y Aplicados (CEIBA) - Gobernación de Bolívar (Colombia).Coronado-Hernández, O.; Fuertes-Miquel, V.; Iglesias-Rey, P.; Mora-Meliá, D. (2018). Parámetros significativos durante los procesos de vaciado en conducciones de agua. Ingeniería del Agua. 22(3):141-152. https://doi.org/10.4995/ia.2018.9292SWORD141152223AWWA. American Water Works Association. Manual of water supply practices M51: air release, air-vacuum, and combination air valves. Denver, USA, 2001.Coronado-Hernández, O.E., Fuertes-Miquel, V.S., Besharat, M., Ramos, H.M. 2017. Experimental and numerical analysis of a water emptying pipeline using different air valves. Water , 9(2), 98. doi:10.3390/w9020098.Coronado-Hernández, O.E., Fuertes-Miquel, V.S., Angulo-Hernández, F.N. 2017. Emptying Operation of Water Supply Networks. Water , 10(1), 22. doi: 10.3390/w10010022.Coronado-Hernández, O.E., Fuertes-Miquel, V.S., Iglesias-Rey, P.L., Martínez-Solano, F.J. 2018. Rigid Water Column Model for Simulating the Emptying Process in a Pipeline Using Pressurized Air. Journal of Hydraulic Engineering (Aceptado). doi: 10.1061/(ASCE)HY.1943-7900.0001446.Coronado-Hernández, O.E., Fuertes-Miquel, V.S., Iglesias-Rey, P.L., Mora-Meliá, D. 2016. Análisis de los fenómenos transitorios generados durante el vaciado de agua en una tubería simple. IAHR - XXVII Congreso Latinoamericano de Hidráulica. Septiembre 28-30. Lima, Perú.Fuertes-Miquel, V.S., Coronado-Hernández, O.E., Iglesias-Rey, P.L., Mora-Meliá, D. 2017. Transient phenomenon during the emptying process of a single pipe with water-air interaction. Journal of Hydraulic Research (pendiente de publicación).Fuertes-Miquel, V. S., López-Jiménez, P. A., Martínez-Solano, F. J., López-Patiño, G. 2016. Numerical modelling of pipelines with air pockets and air valves. Canadian. Journal of Civil Engineering, 43(12):1052-1061.Fuertes-Miquel, V.S. 2001. Hydraulic transients with entrapped air pockets. Ph.D. Thesis, Department of Hydraulic Engineering, Polytechnic University of Valencia, Valencia, Spain.Izquierdo, J., Fuertes, V.S., Cabrera, E., Iglesias, P., García-Serra, J. 1999. Pipeline start-up with entrapped air. Journal of Hydraulic Research, 37, 579-590. doi: 10.1080/00221689909498518.Laanearu, J., Annus, I., Koppel, T., Bergant, A., Vučkovic', S., Hou, Q., Tijsseling, A.S., Anderson, A., Van't Westende, J.M.C. 2012. Emptying of Large-Scale Pipeline by Pressurized Air, Journal of Hydraulic Engineering (138), 1090-1100. doi:10.1061/(ASCE)HY.1943-7900.0000631.León, A., Ghidaoui, M., Schmidt, A., Garcia, M. 2010. A robust two-equation model for transient-mixed flows. Journal of Hydraulic Research, 48, 44-56, http://dx.doi.org/10.1080/00221680903565911.Liou, C., Hunt, W.A. 1996. Filling of Pipelines with Undulating Elevation Profiles. Journal of Hydraulic Engineering 122, 534-539. doi:10.1061/(ASCE)0733-9429(1996)122:10(534).Martins, S.C., Ramos, H.M., Almeida, A.B. 2015. Conceptual analogy for modelling entrapped air action in hydraulic systems. Journal of Hydraulic Research. pp 678-686.Martino, G., Fontana, N., Giugni, M. 2008. Transient flow caused by air expulsion through an orifice. Journal of Hydraulic Engineering, 134(9):1395-1399. doi:10.1061/(ASCE)0733-9429(2008)134:9(1395).Ramezani, L., Karney, B., Malekpour, B.A. 2015. The Challenge of Air Valves: A Selective Critical Literature Review. Journal of Water Resources and Planning Management, doi:10.1061/(ASCE)WR.1943-5452.0000530.Ramezani, L., Karney, B., Malekpour, A. 2016. Encouraging Effective Air Management in Water Pipelines: A Critical Review. Journal of Water Resources Planning and Management 142 (12). doi: 10.1061/(ASCE)WR.1943-5452.0000695.Wang, L., Wang, F., Karney, B., Malekpour, A. 2017. Numerical investigation of rapid filling in bypass pipelines. Journal of Hydraulic Research, 55(5), 647-656. doi:10.1080/00221686.2017.1300193.Wylie, E., Streeter, V. 1993. Fluid transients in systems; Prentice Hall: Englewood Cliffs, NJ, USA.Zhou, L., Liu, D. 2013. Experimental investigation of entrapped air pocket in a partially full water pipe. Journal of Hydraulic Research, 51, 469-474, http://dx.doi.org/10.1080/00221686.2013.785985.Zhou, L., Liu, D., Karney, B. 2013. Investigation of Hydraulic Transients of Two Entrapped Air Pockets in a Water Pipeline. Journal of Hydraulic Engineering 139, 949-959. doi:10.1061/(ASCE)HY.1943-7900.0000750

Breathers in a system with helicity and dipole interaction

Recent papers that have studied variants of the Peyrard-Bishop model for DNA, have taken into account the long range interaction due to the dipole moments of the hydrogen bonds between base pairs. In these models the helicity of the double strand is not considered. In this particular paper we have performed an analysis of the influence of the helicity on the properties of static and moving breathers in a Klein--Gordon chain with dipole-dipole interaction. It has been found that the helicity enlarges the range of existence and stability of static breathers, although this effect is small for a typical helical structure of DNA. However the effect of the orientation of the dipole moments is considerably higher with transcendental consequences for the existence of mobile breathers.Comment: 4pages, 5 eps figure

Effect of Au addition on hydrogen permeation and the resistance to H2S on Pd-Ag alloy membranes

In order to make a detailed comparison between Pd-Ag and Pd-Ag-Au membranes according to their H2 permeation properties and sulfide resistance Au was deposited by the electroless plating (ELP) technique onto one half of Pd-Ag membranes. Membranes' thicknesses are ranged between 2.45 and 3.13 µm. Permeation tests have been carried out from 400 to 600 °C under single gas conditions. The Pd91.7Ag4.8Au3.5 membrane has shown a H2 permeance of 4.71·10−3 mol s−1 m−2 Pa0.5 at 600 °C, which is one of the highest values ever reported in the literature, where the Pd-Ag-Au membranes have exhibited higher hydrogen permeation rates compared to their respective Pd-Ag membranes above 550 °C. The H2 permeation properties have been determined in terms of the degree of H2S inhibition, up to 17 ppm, and subsequent H2 flux recovery rate. Pd-Ag membranes alloyed with gold resisted 12.5 h of H2S exposure showing recovery rates of 85% and 83% for Pd91.5Ag4.7Au3.8 and Pd90.5Ag4.6Au4.9 membranes, respectively, whereas the hydrogen flux of non-gold membranes decreased below detectable values. H2/N2 ideal perm-selectivity of the Pd-Ag membrane was reduced to 18 after H2S tests (starting from > 1308) while Pd-Ag-Au membranes showed a better resistance to sulfur with H2/N2 selectivity values of 793 and 121 (starting from > 4115 and > 2557 respectively). No evidence of the formation of a crystalline sulfide phase on the Pd-Ag-Au alloy membrane surfaces was found in the XRD patterns after H2S exposure and also XPS characterization did not show important changes in the composition before and after the H2S exposure tests. However, SEM images showed a decrease in the thickness of the Pd-Ag membrane and signs of corrosion and roughening on its surface, while gold-alloyed membranes did not show any damage. Keywords Palladium-silver-gold membrane; Electroless plating; H2 permeation; H2S poisoning; H2 recover

Effect of Au addition on hydrogen permeation and the resistance to H2S on Pd-Ag alloy membranes

In order to make a detailed comparison between Pd-Ag and Pd-Ag-Au membranes according to their H2 permeation properties and sulfide resistance Au was deposited by the electroless plating (ELP) technique onto one half of Pd-Ag membranes. Membranes' thicknesses are ranged between 2.45 and 3.13 µm. Permeation tests have been carried out from 400 to 600 °C under single gas conditions. The Pd91.7Ag4.8Au3.5 membrane has shown a H2 permeance of 4.71·10−3 mol s−1 m−2 Pa0.5 at 600 °C, which is one of the highest values ever reported in the literature, where the Pd-Ag-Au membranes have exhibited higher hydrogen permeation rates compared to their respective Pd-Ag membranes above 550 °C. The H2 permeation properties have been determined in terms of the degree of H2S inhibition, up to 17 ppm, and subsequent H2 flux recovery rate. Pd-Ag membranes alloyed with gold resisted 12.5 h of H2S exposure showing recovery rates of 85% and 83% for Pd91.5Ag4.7Au3.8 and Pd90.5Ag4.6Au4.9 membranes, respectively, whereas the hydrogen flux of non-gold membranes decreased below detectable values. H2/N2 ideal perm-selectivity of the Pd-Ag membrane was reduced to 18 after H2S tests (starting from > 1308) while Pd-Ag-Au membranes showed a better resistance to sulfur with H2/N2 selectivity values of 793 and 121 (starting from > 4115 and > 2557 respectively). No evidence of the formation of a crystalline sulfide phase on the Pd-Ag-Au alloy membrane surfaces was found in the XRD patterns after H2S exposure and also XPS characterization did not show important changes in the composition before and after the H2S exposure tests. However, SEM images showed a decrease in the thickness of the Pd-Ag membrane and signs of corrosion and roughening on its surface, while gold-alloyed membranes did not show any damage. Keywords Palladium-silver-gold membrane; Electroless plating; H2 permeation; H2S poisoning; H2 recover