Practical-Oriented Pressure Sensor Placement For Model-Based Leakage Location In Water Distribution Networks

In order to bring remarkable benefits to operation and management of water networks, the analysis of sensed data can be used to locate water leaks using of a model-based methodology. However, the number of sensors installed is usually limited because of budget constraints and hence a strategy for optimizing their number and placement is required. This optimization is tightly coupled to the performance of the real-time model-based leakage diagnosis operation and hence the former should consider the requirements of the latter: (1) high distinguishability among all potential leaks to be detected; and (2) strong robustness in front of model-reality mismatches and other uncertainties. This paper describes a model-based pressure sensor placement optimization technique that focuses on the previous aspects and addresses practicality issues that arise in a real deployment. The technique uses an optimization method based on Genetic Algorithms that, unlike most common approaches in literature, avoids using a binary reasoning process. This increases the information granularity resulting in an improvement of both the leak distinguishability and the method robustness. Moreover, the technique also addresses the practical concerns by deriving an enhanced cost function. Finally, the method is validated in a District Metered Area of the Barcelona water distribution network. Results indicate that a good enough detection accuracy can be achieved with a low number of optimally placed sensors

Contribution à la connaissance des Trichoptères (Trichoptera) du Rif (Nord du Maroc)

L´étude de 6376 spécimens des Trichoptères récoltés dans 103 localités de la chaîne rifaine marocaine entre 2006 et 2010 et la compilation des citations bibliographiques concernant ce groupe d´insectes, ont permis l´identification de 41 espèces dans la zone. Cet inventaire faunistique a enrichi la faune du Rif de 7 espèces non citées antérieurement dans cette zone. Une check-list des Trichoptères identifiées est fournie et la distribution géographique à l´intérieur et à l´extérieur des bassins versants Rifains est discutée pour chacune des espèces, ainsi que quelques notes taxonomiques concernant quelques espèces

Design of Industrial Cold-Formed Steel Rack Upright Frames for Loads in Cross-Aisle Direction

This paper summarizes research on the cross-aisle stiffness and strength of industrial cold-formed steel rack upright frames for loads in cross-aisle direction. Tests were carried out at the Universitat Politècnica de Catalunya, Barcelona, Spain on joints as well as entire upright frames. A possible rather simple analysis procedure is developed and described

Nuevos datos de tricópteros en ríos de referencia de clima mediterráneo en la Península Ibérica y norte de África: aspectos taxonómicos, faunísticos y ecológicos

Trichoptera is a very rich order in the Western Mediterranean, but knowledge of caddisflies in the Iberian Peninsula and northern Africa is still not complete. We present records of caddisflies collected in 114 sites of the Mediterranean climate region of the Iberian Peninsula and the western Rif. We also provide notes on ecological aspects and taxonomical remarks on some species. Atotal of 86 species were identified and 8 species extended their distribution range. Considering the four differentiated geological regions in the western Mediterranean Basin during the Tertiary, 60 species were collected in the Iberian plate region, 29 in the Transition, 30 in the Betic and 18 in the Rif. Local richness was not significantly different between the four regions but significant differences were found among several river ecotypes within regions. Temporary sites had lower local richness than other ecotypes in all regions except in the Rif, whereas headwaters had similar richness in any region regardless of their geology. The Rif region had the lowest Trichoptera richness, which is not only the result of the scarcity of faunistic studies in the area but also of the high frequency of temporary rivers and the isolation of the area. Our results suggest that conservation measures addressed to preserve the biodiversity of the Western Mediterranean should be enforced, especially in the Rif region.El orden Trichoptera es rico en especies en la zona del Mediterráneo Occidental, pero el conocimiento de este grupo en la Península Ibérica y el norte de África resta aún de ser completo. Presentamos datos de tricópteros recolectados en 114 localidades de la región Mediterránea de la Península Ibérica y del Rif occidental. Además, proporcionamos datos sobre la ecología de algunas especies así como notas taxonómicas. Se identificaron un total de 86 especies y el rango de distribución aumentó para 8 de ellas. Sesenta especies se recolectaron en la región de la placa Ibérica, 29 en la de Transición, 30 en la Bética y 18 en el Rif, las cuatro regiones geológicas diferenciadas durante el Terciario en el Mediterráneo Occidental. La riqueza local no fue significativamente diferente entre regiones geológicas, pero sí entre varios ecotipos fluviales. Los tramos temporales presentaron una riqueza local menor que los demás ecotipos, excepto en el Rif, mientras que las cabeceras presentaban una riqueza similar en cada región independientemente de su geología. Globalmente el Rif presentó una menor riqueza de tricópteros, lo que se explica no sólo por la escasez de estudios faunísticos en la zona sino también por la elevada frecuencia de ríos temporales y su aislamiento geográfico. Nuestros resultados sugieren que en la zona del Mediterráneo Occidental se deben de llevar a cabo medidas de conservación urgentes para preservar su biodiversidad, especialmente en la región del Rif

Viticulture adaptation to global warming: Modelling gas exchange, water status and leaf temperature to probe for practices manipulating water supply, canopy reflectance and radiation load

Associated with climate change, the frequency, duration, and intensity of heatwaves are increasing in most of the key wine regions worldwide. Depending on timing, intensity, and duration, heatwaves can impact grapevine yield and berry composition, with implications for wine quality. To overcome these negative effects, two types of mitigation practices have been proposed (i) to enhance transpiration and (ii) to reduce the radiation load on the canopy. Here we use a biophysical model to quantify the impact of these practices on canopy gas exchange, vine water status, and leaf temperature (Tl). Model validation was performed in a commercial vineyard. Modelled Tl from 14 to 43 °C, and transpiration, from 0.1 to 5.4 mm d−1, aligned around the identity line with measurements in field-grown vines; the RMSD was 2.6 ºC for temperature and 0.96 mm day−1 for transpiration. Trellis system and row orientation modulate Tl. A sprawling single wire trellis with an EW orientation maintained the canopy around 1ºC cooler than a Vertical Shoot Positioned canopy with NS for the same range of total fraction of soil available water (TFAW). Although irrigation before a heatwave is a recommended practice, maximum transpiration can be sustained even when TFAW is reduced, limiting the heat dampening effect of irrigation. Alternatively, canopy cooling can be achieved through Kaolin application, the installation of shade cloth placement, or canopy trimming. Shade cloth produced a greater cooling than Kaolin in all the simulated scenarios; however, Tl differences between them varied. Trimming reduced Tl from 2 ºC to almost 8 ºC compared to its non-trimmed counterpart. Our analysis presents new insights to design heat wave mitigation strategies and supports agronomically meaningful definitions of heat waves that include not only temperature, but also wind, VPD, and radiation load as these factors influence crop physiology under heat stress.info:eu-repo/semantics/publishedVersio

Industrial Cold-Formed Steel Rack Column Base Fixity and Strength

This paper summarizes the testing done at the Universitat Politècnica de Catalunya, Barcelona, Spain and the possible use of the results in design for column base stiffness and strength. The test setup and procedure are adopted in the European rack design standards

On The Structure Of The Objective Function For A Pressure Sensor Placement Optimizing Methodology Based On Genetic Algorithms Applied To Model-Based Leakage Localization In Distribution Water Networks

Real-time monitoring of distribution water networks relies on the deployment of sensors and the availability of their measurements in order to predict the system state and assess its performance. A meaningful application of this methodology is the detection and localization of leaks using model-based approaches. Since the number of sensors is limited because of budget constraints, it is important to place these devices in locations where the effectiveness of the leakage diagnosis is maximized. Finding the best sensor distribution is a global optimization problem defined by an objective function that might depend on different factors. Therefore, deriving the correct structure of such function is a crucial step as a wrong definition would lead towards a confusing optimal solution affecting negatively the monitoring performance. In general, sensor placement optimization methods describe objective functions using factors related to the amount of undistinguishable leaks. More concretely, the methods first compute groups of locations where leaks cannot be differentiated and then maximize this number of groups or minimize their size. In this paper, additional factors are presented to accurately represent the requirements of the leak diagnosis phase. These include other statistical figures related to the size of groups, geographical characteristics like the group’s extension area, levels of sensitivity that indicate whether a location is more or less sensible to pressure changes, etc. The objective of this study is to review several factors in order to comprehend their behaviour and justify or discard them for the objective function. The indicators under study are evaluated by means of a cross-correlation analysis applied to the scenario defined by the District Metered Area of the Barcelona water distribution. Results indicate the existence of different independency levels between the indicators that allow us to select those with less redundancy

Presencia de la familia Helicopsychidae (Trichoptera) en la mitad meridional de España peninsular

La familia Helicopsychidae Ulmer, 1906, cuesta con unas 250 especies distribuidas por todo el mundo y pertenecientes en casi su totalidad al género Helicopsyche von Siebold, 1856, salvo una especie endémica de Nueva Zelanda: Rakiura vernale McFarlane, 1973

The effects of climatic fluctuations and extreme events on running water ecosystems

Most research on the effects of environmental change in freshwaters has focused on incremental changes in average conditions, rather than fluctuations or extreme events such as heatwaves, cold snaps, droughts, floods or wildfires, which may have even more profound consequences. Such events are commonly predicted to increase in frequency, intensity and duration with global climate change, with many systems being exposed to conditions with no recent historical precedent. We propose a mechanistic framework for predicting potential impacts of environmental fluctuations on running water ecosystems by scaling up effects of fluctuations from individuals to entire ecosystems. This framework requires integration of four key components: effects of the environment on individual metabolism, metabolic and biomechanical constraints on fluctuating species interactions, assembly dynamics of local food webs and mapping the dynamics of the meta-community onto ecosystem function. We illustrate the framework by developing a mathematical model of environmental fluctuations on dynamically assembling food webs. We highlight (currently limited) empirical evidence for emerging insights and theoretical predictions. For example, widely supported predictions about the effects of environmental fluctuations are: high vulnerability of species with high per capita metabolic demands such as large-bodied ones at the top of food webs; simplification of food web network structure and impaired energetic transfer efficiency; reduced resilience and top-down relative to bottom-up regulation of food web and ecosystem processes. We conclude by identifying key questions and challenges that need to be addressed to develop more accurate and predictive bio-assessments of the effects of fluctuations, and implications of fluctuations for management practices in an increasingly uncertain world