Modeling circulation patterns induced by spatial cross-shore wind variability in a small-size coastal embayment

This contribution shows the importance of the cross-shore spatial wind variability in the water circulation in a small-sized micro-tidal bay. The hydrodynamic wind response at Alfacs Bay (Ebro River delta, NW Mediterranean Sea) is investigated with a numerical model (ROMS) supported by in situ observations. The wind variability observed in meteorological measurements is characterized with meteorological model (WRF) outputs. From the hydrodynamic simulations of the bay, the water circulation response is affected by the cross-shore wind variability, leading to water current structures not observed in the homogeneous-wind case. If the wind heterogeneity response is considered, the water exchange in the longitudinal direction increases significantly, reducing the water exchange time by around 20%. Wind resolutions half the size of the bay (in our case around 9 km) inhibit cross-shore wind variability, which significantly affects the resultant circulation pattern. The characteristic response is also investigated using idealized test cases. These results show how the wind curl contributes to the hydrodynamic response in shallow areas and promotes the exchange between the bay and the open sea. Negative wind curl is related to the formation of an anti-cyclonic gyre at the bay's mouth. Our results highlight the importance of considering appropriate wind resolution even in small-scale domains (such as bays or harbors) to characterize the hydrodynamics, with relevant implications in the water exchange time and the consequent water quality and ecological parameters.Peer ReviewedPostprint (author's final draft

Mycelium-enhanced bacterial degradation of organic pollutants under bioavailability restrictions

This work examines the role of mycelia in enhancing the degradation by attached bacteria of organic pollutants that have poor bioavailability. Two oomycetes, Pythium oligandrum and Pythium aphanidermatum, were selected as producers of mycelial networks, while Mycobacterium gilvum VM552 served as a model polycyclic aromatic hydrocarbon (PAH)-degrading bacterium. The experiments consisted of bacterial cultures exposed to a non-disturbed non-aqueous phase liquid (NAPL) layer containing a heavy fuel spiked with 14C-labeled phenanthrene that were incubated in the presence or absence of the mycelia of the oomycetes in both shaking and static conditions. At the end of the incubation, the changes in the total alkane and PAH contents in the NAPL residue were quantified. The results revealed that with shaking and the absence of mycelia, the strain VM552 grew by utilizing the bulk of alkanes and PAHs in the fuel; however, biofilm formation was incipient and phenanthrene was mineralized following zero-order kinetics, due to bioavailability limitation. The addition of mycelia favored biofilm formation and dramatically enhanced the mineralization of phenanthrene, up to 30 times greater than the rate without mycelia, possibly by providing a physical support to bacterial colonization and by supplying nutrients at the NAPL/water interface. The results in the static condition were very different because the bacterial strain alone degraded phenanthrene with sigmoidal kinetics but could not degrade alkanes or the bulk of PAHs. We suggest that bacteria/oomycete interactions should be considered not only in the design of new inoculants in bioremediation, but also in biodegradation assessments of chemicals present in natural environments

Numerical modelling of pollutant transport in stratified coastal water using finite volume method and unstructured mesh

Conèixer la dispersió de substàncies en l'aigua ñes bàsic per a conèixer els porcessos ambientals i la gestió de la hidrosfers marina. En aquesta tesina s'analitza la predicció del fenomen del transport de contaminants en ambients costaners en presència d'estratificació utilitzant un model numèric. El model numèric utilitzat fa servir malles no estructurades (Unstructured Mesh) per la discretització del domini i Volums Finits ( Finite Volume Method) per l'aproximació numèrica de l'equació del transport. Així doncs el principal objectiu del treball és avaluar la idoneïtat d'utilitzar aquestes dues eines numèriques per implementar models de predicció del fenomen del transport

A statistical forecasting model applied to container throughput in a multi-port gateway system: the Barcelona-Tarragona-Valencia case

This contribution investigates the container throughput flow in a multi-port gateway system: Barcelona-Tarragona-Valencia (BTV). First, the paper examine the recent dynamics of the total and transshipment flow showing a relevant shifting of traffic share from Barcelona to Valencia. A statistical model based on a two-state Markov model in conjunction with a Monte Carlo experiments is implemented to estimate the predictions of container throughput in BTV system. Verification tests shows how the predictions are reasonable good with an error metrics similar to other methods based on time series analysis. The method is considered suitable for short-term forecasting with a strong potential to be used as a complement of qualitative methods due to the statistical nature of the results. The implementation of the method considers separately the import/export and transhipment container throughput revealing a differentiate dynamics in both container flows. The transhipment flow is more volatile and induce more data dispersion in the container throughput predictions.Peer ReviewedPostprint (author's final draft

Enhancement of Maritime Safety and Economic Benefits of Short Sea Shipping Ship Routing

The relevance of ship routing system is increasing according to the mitigation of carbon emissions and enhance the maritime safety. New generation of high-resolution meteo-oceanographic predictions provides useful tools for routing of ship. However, scientific efforts have been focused on inter-oceanic routes. This contribution investigates the economic benefits and improvement on maritime safety of ship routing of Short Sea Shipping (SSS) routes. The investigation is supported with the development of a ship routing system based on a path finding algorithm and meteo-oceanographic predications. Results show that the economic benefits using ship routing in SSS is estimated in percentage of the total cost during energetic wave episodes. The work establishes the basis of further developments in optimal route applied in relatively short-distances and its systematic use in the SSS maritime industry. In this work, the optimal ship routing analysis is investigated in a relative short distance maritime route between Barcelona and Palma de Mallorca (Spain). Dijkstra algorithm is implemented in order to obtain the optimal path under an energetic wave event. The methodology is based on the inclusion of the drag resistance due to waves. The results reveal how the wave direction has a relevant role in the optimum path due to the relative direction with the ship and the enhancement of the navigational safety.Postprint (published version

L'acreditació i la garantia externa de la qualitat de la universitat com a resposta a la internacionalització dels ensenyaments universitaris i a l'establiment de l'espai europeu d'educació superior

Aquest article relaciona el nou entorn en què les universitats se situen amb l'establiment de l'espai europeu d'educació superior (EEES) i l'ús de mecanismes de garantia de la qualitat externa (acreditació). Davant de la necessitat de preservar la característica de bé públic que té la formació universitària en un entorn de competitivitat creixent que prové de la internacionalització, l'article assenyala el desenvolupament dels mecanismes de garantia de la qualitat en els sistemes universitaris com a element clau per equilibrar les forces del lliure mercat, tot estimulant una distribució adequada de prioritats i recursos en pro de la modernització de les universitats en un territori determinat. A la segona part, s'hi presenta un seguit de reflexions al voltant dels estàndards d'acreditació que es proposen per als programes universitaris, en la línia d'obrir un debat sobre el disseny de la formació universitària, més enllà de l'objectiu d'explicitar-ne de manera immediata el reconeixement extern de la qualitat, entenent que els estàndards han de pensar-se com una via de transformació progressiva de la universitat.This article associates the new context of the universities with the setting up of the European Higher Education Area and the use of external quality assurance mechanisms (accreditation). In view of the need to preserve the characteristic of university education as a public good within the context of increasing competitivity stemming from internationalisation, the article points to the development of quality assurance systems in university systems as a key element in balancing out free market forces by stimulanting the adequate distribution of priorities and resources in favour of the modernisation of the universities within a given geographical area. The second part of the article gives a series of reflections on the accreditation standards being proposed for university programmes as a way of opening a debate on the design of university education beyond the more immediate aim of the external recognition of quality, with accreditation standards understood as being a way for progressively transforming the university

Optimization on emergency materials dispatching considering the characteristics of integrated emergency response for large-scale marine oil spills

Many governments have been strengthening the construction of hardware facilities and equipment to prevent and control marine oil spills. However, in order to deal with large-scale marine oil spills more efficiently, emergency materials dispatching algorithm still needs further optimization. The present study presents a methodology for emergency materials dispatching optimization based on four steps, combined with the construction of Chinese oil spill response capacity. First, the present emergency response procedure for large-scale marine oil spills should be analyzed. Second, in accordance with different grade accidents, the demands of all kinds of emergency materials are replaced by an equivalent volume that can unify the units. Third, constraint conditions of the emergency materials dispatching optimization model should be presented, and the objective function of the model should be postulated with the purpose of minimizing the largest sailing time of all oil spill emergency disposal vessels, and the difference in sailing time among vessels that belong to the same emergency materials collection and distribution point. Finally, the present study applies a toolbox and optimization solver to optimize the emergency materials dispatching problem. A calculation example is presented, highlighting the sensibility of the results at different grades of oil spills. The present research would be helpful for emergency managers in tackling an efficient materials dispatching scheme, while considering the integrated emergency response procedure.Peer ReviewedPostprint (published version