25 research outputs found
Numerical simulation of runoff from extreme rainfall events in a mountain water catchment
A numerical model for unsteady shallow water flow over initially dry areas is applied to a case study in a small drainage area at the Spanish Ebro River basin. Several flood mitigation measures (reforestation, construction of a small reservoir and channelization) are simulated in the model in order to compare different extreme rainfall-runoff scenarios
Optimal design of drip irrigation submains: presure-compensating emitters
For a drip irrigation system to be successful, it must he well designed, properly installed, managed and maintained. In plots with steep slopes and irregular topography that have little land leveling capacity and/or that require very efficient agricultural machinery, drip irrigation designs generally use pressure-compensating emitters. This work develops a methodology and implements it in a computer tool that makes it possible to optimally determine in drip-irrigated plots with pressure-compensating emitters: a) telescopic sizing of the submain manifold pipe, b) supply valve pressure and c) subunit''s intake valve location, when considering all hydraulic-economic aspects in the design phase. Techniques of optimal sizing of pipe networks and simulation of hydraulic networks under pressure are linked to economic analyzes of total annualized costs. Finally, the practical usefulness of the proposed methodology is shown with three examples of complex real cases where pipe design costs are reduced by 16-34% and energy costs by 37-51%
Transferencia de resultados de investigación para el ahorro de agua y de la energía en comunidades de regantes a través del entorno de gestión integrada CORENET-COREGEST
En la actualidad se está produciendo un incremento en la demanda para realizar una gestión
optimizada del agua y de la energía empleadas en el regadío. Esto ha dado lugar a una
importante actividad de I+D con diferentes sistemas, productos y servicios, que comparten el
objetivo de mejorar la aplicación del agua y/o de la energía. Sin embargo, el conocimiento
generado choca con dificultades a la hora de transferir los resultados hacia los usuarios
finales. Esto es debido, al menos en parte, a la necesidad de que las Comunidades de
Regantes cambien su modelo de gestión y sean capaces de integrar los resultados de este
conocimiento con los procesos normales de gestión que se emplean en las mismas.
SERINA ha desarrollado la metodología y el Enterprsise Resource Planning (ERP) de
gestión CORENET-COREGEST, que permite modernizar los procesos de gestión de las
Comunidades de Regantes e integrar herramientas/sistemas/servicios externos generados
por los centros de I+D con el objetivo de mejorar la gestión, fundamentalmente, del agua y
de la energía.
En este trabajo se muestran algunos casos que ilustran lo anterior y se explican las ventajas
para las Comunidades de Regantes usuarias así como por los centros de I+D que han
integrado sus productos en CORENET-COREGEST
Metodología para la optimización conjunta de la programación del riego y estaciones de bombeos directos
Se describe una nueva metodología para reducción de los costes energéticos de operación del riego en redes de riego con bombeo directo, contemplando la optimización conjunta de la organización de los riegos y la modulación de las presiones de la estación de bombeo a lo largo de diferentes periodos tarifarios. Se describe el funcionamiento del método de optimización investigado, que es una extensión y mejora del algoritmo inicial existente desarrollado en (Faci E., 2014) destacando las diferencias y mejoras. Por último, se muestran los resultados en el caso de la red de la CR Callén (Huesca), y se comparan con los obtenidos en un estudio para la optimización energética utilizando el algoritmo inicial.A new methodology to reduce energy cost in irrigation networks is developed in this paper. Its goal is to optimize simultaneously both pumping station and hydrant operation by setting different discharge pressure on the pumping station and distributing adequately hydrant irrigation during different tariff periods. methodology is an extension an existing one described in Faci E., (2014) which is only capable of optimize hydrant operation. Advantages and differences between them are described and they are compared in the case study of CR Callén network (Huesca) which shows the new methodology is capable to save an additional 10% of the annual electricity costs
Irrigation and energy: Issues and challenges
Water‐efficient agriculture has implied a large increase in energy consumption for irrigation in recent decades. In many irrigation systems, energy costs are now threatening their sustainability. However, new opportunities have arisen for the use of renewable energies in the irrigation sector. These are some of the aspects of the multifaceted multiple‐actor 'water–food–energy' nexus. Technical, economic and environmental issues are linked in many ways, involving farmers, water users' associations, energy suppliers, engineers and other stakeholders. The ICID session 'Irrigation and energy' triggered discussions on these multiple dimensions. This paper presents a synthesis of the presentations, discussions and conclusions. Four main questions are addressed: How do irrigation productivity and sustainability of water resources exploitation change when farmers have access to energy? What do we know about energy efficiency in irrigation systems, at farm and collective network levels? How can this efficiency be optimized by using advanced technologies, modelling tools, improved management? Is energy production an opportunity for irrigation systems? These questions have been posed based on multiple case studies from different parts of the world. The BRL network, in southern France, illustrates advanced strategies and opportunities to reduce energy consumption and develop energy production at a network level. General conclusions are drawn from this synthesis, illustrating trade‐offs and synergies that can be identified in the irrigation sector at different scales, while opportunities for future research are proposed
Discussion on second-order dispersed phase Eulerian equations applied to turbulent particle-laden jet flows
In this work a Reynolds stress two-phase flow model is presented. Equations for the second-order statistical moments are considered for both phases, continuous and dispersed, in the limit of high-inertia non-colliding particles. A simplified version of this model is used for studying axisymmetric particle-laden gas jets. Emphasis is made in the analysis of the dispersed phase equations only. The equations for radial and axial momentum and normal Reynolds stresses for the particulate phase are divided into their basic terms and analysed separately. The modelling of the corresponding shear stresses relies on a Boussinesq closure, consistent with the theoretical work of Reeks (Phys. Fluids A 5(3) (1993) 750) and Zaichik (J. Appl. Math. Mech. 61 (1997) 127) in the limit of high-inertia particles. By this procedure a global picture of the momentum and fluctuating energy transfer in the flow is attained. Moreover, the dispersed phase and fluid-particle velocity correlation, that enter the interaction terms describing the exchange of fluctuating energy between the phases, are compared with the result of Reeks' and Zaichik's theoretical expressions in the case of simple shear flow. © 2003 Elsevier Ltd. All rights reserved.The financial support by the Commission of the European Communities in the frame of a Marie Curie Research Training Fellowship (Contract No. CT-97-2206) is gratefully acknowledged.Peer Reviewe
Towards answer extraction: an application to technical domains
The shortcomings of traditional Information Retrieval are most evident when users require exact information rather than relevant documents. This practical need is pushing the research community towards systems that can exactly pinpoint those parts of documents that contain the information requested. Answer Extraction (AE) systems aim to satisfy this need. This paper presents one such system (ExtrAns) which works by transforming documents and queries into a semantic representation called Minimal Logical Form (MLF) and derives the answers by logical proof from the documents. MLFs use underspecification to overcome the problems associated with a complete semantic representation and offer the possibility of monotonic, non-destructive extension
Answer Extraction from Technical Texts
For most companies and organizations, technical documents are highly valued knowledge sources because they combine the know-how and experience of specialists in a particular domain. To guarantee the optimal use of these documents in specific problem situations, people must be able to quickly find precise and highly reliable information. Answer extraction is a new technology that helps users find precise answers to their questions in technical documents. In this article, the authors present ExtrAns, a real-world answer extraction system designed for technical domains. ExtrAns uses robust natural language processing technology and a semantic representation for information's propositional content. Knowing the forms of a domain's terminology and understanding the relation between the terms is vital for answer extraction. By applying rewrite rules in a systematic way, ExtrAns gets a grip on technical terminology
NLP for answer extraction in technical domains
In this paper we argue that question answering (QA) over technical domains is distinctly different from TREC-based QA or Web-based QA and it cannot benefit from data-intensive approaches. Technical questions arise in situations where concrete problems require specific answers and explanations. Finding a justification of the answer in the context of the document is essential if we have to solve a real-world problem. We show that NLP techniques can be used successfully in technical domains for high-precision access to information stored in documents. We present Extr- Ans, an answer extraction system over technical domains, its architecture, its use of logical forms for answer extractions and how terminology extraction becomes an important part of the system