14 páginas, 3 tablas ; Fish discards and by-catch issues are highly topical subjects that are permanently under a social focus. Two main approaches are being considered to address this discard problem: reducing the by-catch and increasing by-catch utilization. Interest in increased by-catch valorization may arise from a greater demand for fish products, such as the development of new markets for previously discarded species, the use of low-value specimens for aquaculture or the creation of value-added fish products for the food, pharmaceutical or cosmetic industries. However, contaminants present in fish discards may be transferred to their valorized products, leading to possible long-term bioaccumulation and subsequent adverse health effects. In this valorization framework, the aim is to promote responsible and sustainable management of marine resources. The pollutant levels in catches from European fisheries and the best available decontamination techniques for marine valorized discards/by-products are compiled and analyzed in this work. ; The authors acknowledge the financial support received from the LIFE + Program of the European Union (FAROS Project – LIFE08 ENV/E/000119). ; Peer reviewed
7 páginas, 2 figuras ; In this letter we show that closed reversible chemical reaction networks with independent elementary reactions admit a global pseudo- Hamiltonian structure which is at least locally dissipative around any equilibrium point. The structure matrix of the Hamiltonian description reflects the graph topology of the reaction network and it is a smooth function of the concentrations of the chemical species in the positive orthant. The physical interpretation of the description is briefly explained and two illustrative examples are presented for global and local dissipative Hamiltonian description, respectively. ; The authors acknowledge financial support received from the Spanish Government (MCyT Projects PPQ2001-3643 & DPI2004-07444-C04-03) and Xunta de Galicia (PGIDIT02- PXIC40209PN). This research was partially supported by the Hungarian grant nos. K67625, F046223, which are gratefully acknowledged. The second author is a grantee of the Bolyai J´anos Research Scholarship of the Hungarian Academy of Sciences. ; Peer reviewed
11 páginas, 2 figuras ; In the present work, we combine the concepts and tools from Irreversible Thermodynamics and Control Theory in a contribution to unravel the origin of complex nonlinear behaviour in biochemical networks. Regarding cells as thermodynamic systems, we can consider dynamic evolution of intracellular processes in terms of the combined action of an endogenous entropy production and the entropy flux associated to chemicals passing through the control volume. Based on a generalized description of biochemical systems, a physically motivated storage function is constructed and used for stability analysis. In this way, the entropy flux of open systems can be meaningfully modified by efficient nonlinear control schemes capable of network stabilization, and irreversible thermodynamics provide us with the physical insight to further interpret the controlled response. ; The authors acknowledge financial support received from the Spanish Government (MCyT Projects PPQ2001-3643 and DPI2004-07444-C04-03) and Xunta de Galicia (PGIDIT02-PXIC40209PN). This research was partially supported by the Hungarian grants no. T042710, F046223, which are gratefully acknowledged. The second author is a grantee of the Bolyai J´anos Research Scholarship of the Hungarian Academy of Sciences. ; Peer reviewed
21 páginas, 24 figuras, 5 tablas ; The need of designing decentralized control loops emerges to ensure the global stability of a given process plant. To that purpose, it has been proposed in recent works a systematic approach to derive robust decentralized controllers, which is based on the link between thermodynamics and passivity theory, as well as on the fundamentals of process networks. This thermodynamic-based control (TBC) methodology has several steps: (1) Decomposition of the considered process system into abstract mass and energy inventory networks; (2) design of conceptual mass and energy inventory control loops to guarantee the convergence of the states of the plant to a compact convex region defined by constant inventories, where input-output stability follows; (3) definition of intensive variable control loops (if needed) to achieve global stability, and (4) realization of the conceptual inventory and intensive variable control loops over the available degrees of freedom in the system by using, for instance, PI controllers. A tool to tune these PI control loops is developed, based on the solution of a nonlinear programming optimization problem (NLP), in order to complete the proposed hierarchical and systematic TBC design. The aim is to minimize a given cost function, subject to both the system dynamics, as well as the linear and nonlinear constraints (no disturbances affecting the system are considered), where the vector of decision variables will be formed by the parameters of the PI controllers used in the defined decentralized control loops. We will test this tuning procedure in several control designs developed for the challenging benchmark of the Tennessee Eastman Process (TEP) by Ricker and Larsson et al., as well as in two TBC candidates, concluding that the best candidate among the proposed ones (in terms of final cost function) will be one of these TBC designs. For solving the NLP problem, two local (FMINCON and NOMADm) solvers, and a new global (MITS) one are used, comparing their performances. Finally, the dynamic analysis of the optimal tuned closed loop systems is carried out, finding that the presented TBC control candidates will be stable, while the other control structures considered exhibit complex dynamic behaviors or even instability when disturbances affecting the process are considered ; The authors acknowledge the financial support received from the Spanish Government (MCyT Projects PPQ2001-3643), Xunta de Galicia (PGIDIT02-PXIC40209PN) and "PRIMS" Marie Curie Action (MRTN-CT-2004-512233). ; Peer reviewed
This book explains the challenges and barriers of island energy systems in the European Union. It reviews the research projects carried out to date, and proposes a new feasible scheme that could be advantageous to many isolated energy systems. The book contains a thorough literature review, to ensure the originality of its ideas. It provides a clear insight of the opportunities and difficulties facing EU island energy systems.
12 pages, 2 tables, 3 figures.-- This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms ; A realistic description of the variability in bacterial growth and division is critical to produce reliable predictions of safety risks along the food chain. Individual-based modeling of bacteria provides the theoretical framework to deal with this variability, but it requires information about the individual behavior of bacteria inside populations. In this work, we overcome this problem by estimating the individual behavior of bacteria from population statistics obtained with flow cytometry. For this objective, a stochastic individual-based modeling framework is defined based on standard assumptions during division and exponential growth. The unknown single-cell parameters required for running the individual-based modeling simulations, such as cell size growth rate, are estimated from the flow cytometry data. Instead of using directly the individual-based model, we make use of a modified Fokker-Plank equation. This only equation simulates the population statistics in function of the unknown single-cell parameters.We test the validity of the approach by modeling the growth and division of Pediococcus acidilactici within the exponential phase. Estimations reveal the statistics of cell growth and division using only data from flow cytometry at a given time. From the relationship between the mother and daughter volumes, we also predict that P. acidilactici divide into two successive parallel planes ; The authors acknowledge financial support from the Spanish Government (MINECO) and the European Regional Development Fund (ERDF) through the projects "RESISTANCE" (DPI2014-54085-JIN) and "IMPROWINE" (AGL2015-67504-C3-2-R) and from the Spanish Council for Scientific Research (CSIC) for the project PIE 201230E042. We also acknowledge funds received from the Axencia Galega de Investigación (GAIN) ; Peer reviewed
7 páginas, 3 figuras, 2 tablas ; Sustainability of the fisheries sector is nowadays a key issue due to the significant impact that this activity may have on the environment. Besides fishing activity itself, other indirect impacts, like those originated from related activities and services also need to be addressed. For assessing the environmental burden of this sector, the Ecological Footprint (EF) indicator can be used. The application of EF to the fisheries sector is still uncommon and studies of associated activities (such as ports) even more. In this work, classical EF methodology was applied in order to evaluate the environmental impact of the fisheries sector, taking as a representative sample the global activity (fishing and transportation) of the Port of Vigo (Spain), one of the biggest fishing ports in the world. A high value of total EF for both port and fishing activities was obtained. However, relative EF is much higher in the case of fishing, due to the low natural productivity associated to fish resources. Energy-land and sea area were the most affected land-components within the footprint, while among the different categories, resources consumption was the main contributor to the EF value in all the assessed scenarios. ; European Union through the LIFE Environment Program of the European Union (LIFE05 ENV/E000267-BE FAIR and LIFE08 ENV/E/000119-FAROS) ; Peer reviewed
4 figuras, 2 tablas ; The global harvesting of marine products has increased from around 17 million tons in the 1950s to a current average amount of 85 million tons. The Food and Agriculture Organization (FAO) estimates that an annual average of 27 million tons of non-targeted species are caught and thrown back into the sea, what means that near third of the fish volume captured every year is wasted. This in itself represents a purposeless waste of valuable living resources, but in addition, the large amounts of organic waste thrown into the sea may produce severe adverse effects on the ecological equilibrium of marine communities. In this context, the BEFAIRinitiative1 (www.befairproject.com) -co-founded under the LIFE Environment Program of the European Union- was devised in the intention to contribute to a responsible and sustainable management of fisheries by making the bestpossible use of the captured resources avoiding its waste. This paper discusses the main actions taken in the project, which in the purpose of reducing the costs associated to the implementation of that so-called zero-discard and zero-waste policy, were directed to the development and implementation of integral management and novel processing practices. The aim of these actions is to upgrade captured resources (by-catch and wastes produced by fish processing) and thus to obtain added value products of interest in the food industry ; Financial support received from the European Union through the LIFE Environment Program of the European Union (LIFE05 ENV/E000267-BE FAIR). ; Peer reviewed
The aim of this work is to develop a visual interface including the most representative processes in the gelatin production from fish skin. Connecting different components from a library implemented in EcosimPro, users can easily configure a virtual plant according to their requirements, and test different scenarios attending to the quantity and quality of the raw material (normally subject to seasonal variations). In this way, it is possible to analyze the consumption of water, energy and reactives, as well as the quality and quantity of the product obtained by given variations in the inputs and/or the operational parameters. The approach is multipurpose, combining elements of design and simulation. ; The authors acknowledge financial support from the Galician Government through grant PGIDIT04TAM007001CT and fromthe European Union (Project BEFAIR EU LIFE05 ENV/E000267.BE FAIR) ; Peer reviewed
14 páginas, 2 tablas, 9 figuras, 2 apéndices ; The dissipative nature of spatially distributed process systems is exploited to develop efficient exponential state observers based on a low-dimensional dynamic representation of the original set of partial differential equations. The suggested approach combines standard observer design techniques for reactors, where the reaction rates are unknown with efficient model reduction methodologies based on projection of the original concentration and temperature fields on low-dimensional subspaces capturing the slow dynamics of the process. The global exponential stability of the resulting observer is derived combining classical Lyapunov analysis with a transformation that allows us to obtain a diffusion system from a diffusion-convection system. In addition, aspects related to the location of sensors and their influence on the ability to reconstruct the necessary fields to feed the observer will also be considered ; The authors acknowledge financial support received from the Spanish Government (MCyT Projects PPQ2001-3643 and DPI2004-07444-C04-03) and Xunta de Galicia (PGIDIT02-PXIC40209PN) ; Peer reviewed
10 páginas, 8 figuras, 2 tablas ; In this article, we develop a systematic approach for efficient field reconstruction in distributed process systems from a limited number of measurements. The approach generalizes previous methods for sensor placement so as to be able to handle field reconstruction problems in arbitrary spatial domains where complex nonlinear phenomena take place. Pattern formation in fluid dynamics or diffusion-reaction systems are examples exhibiting complex nonlinear distributed behaviors, especially when taking place in arbitrary 2D or 3D domains. Our approach exploits the dissipative nature of the diffusion-convection process and the underlying algebraic structure of the finite element method to efficiently construct field representations in terms of globally defined basis functions and to optimally select the placement of sensors. The results will be illustrated on a fluid dynamic process: the Rayleigh−Bénard problem ; The authors acknowledge financial support received from the Spanish Government (DPI2004-07444-C04-03) and Xunta de Galicia (PGIDIT02-PXIC40209PN). ; Peer reviewed
