Repasivation of steel rebars after and electrochemical chlorides removal treatment by simultaneous application of calcium nitrite

The Electrochemical Removal of Chlorides (CE) can be proposed as methodology for the treatment of reinforced concrete structures affected by corrosion. This methodology is based on the temporary application of an external voltage between an external anode located on the concrete and the rebar connected as cathode. After the treatment, the extraction of chloride from the concrete level and the repassivation of the rebar are expected. The migration of ionic inhibitors to the rebar could be considered during the connection of an electric field to favour the regeneration of the passive film. In present work a novel methodology is proposed to enhance the efficiency of an Electrochemical Chloride Extraction treatment by simultaneous application of calcium nitrite. A fast repassivation of the rebar is reached after the CE treatment when the inhibitor is applied during the electric field connection. The penetration of the inhibitor near the rebar surface has been confirmed by. The new passive conditions of the steel rebar after the treatment were confirmed by electrochemical measurements. The penetration of the inhibitor near the rebar surface was assured by analysing of nitrite dissolved into the aqueous phase. The presence of nitrite promoted a faster regeneration of the passive film that is maintained in time

Enhancement of electrochemical chloride removal using corrosion inhibitors

Corrosion inhibitors can be introduced through concrete pores under the action of an electrical field. In this work, migration of corrosion inhibitors from the surface of the concrete, simultaneously to Electrochemical Chloride Removal (ECR), is considered. Two methods are proposed: 1) Connection of rebar as cathode for application of cationic inhibitors, and 2) Connection of rebar to an external cathode for application of anionic inhibitors. Results show that the migration of inhibitors, simultaneously to ECR improves the efficiency of the treatment by removing more chlorides and enhancing the passivation process of the reinforcement after the treatmen

Primera cita de un Blastoideo Coronado en el Ordovícico Superior de Sierra Morena Oriental

En este trabajo se describe y figura el primer hallazgo de un Blastoideo Coronado en los sedimentos del Caradoc Superior de El Viso del Marqués (provincia de Ciudad Real). El nuevo material descrito nos permite analizar la filogenia de los Coronados, su posición sistemática y su modo de vida. El sistema respiratorio, los procesos coronales, se considera como un tipo primitivo de hidrospira, homólogo al definido en Eublastoideos; Por otro lado, se describe el primer caso documentado de alometría en Coronados

Trophic consequences of introduced species: comparative impacts of increased inter-specific versus intra-specific competitive interactions

1. Invasive species can cause substantial ecological impacts on native biodiversity. Whilst ecological theory attempts to explain the processes involved in the trophic integration of invaders into native food webs and their competitive impacts on resident species, results are equivocal. In addition, quantifying the relative strength of impacts from non-native species (inter-specific competition) versus the release of native conspecifics (intra-specific competition) is important but rarely completed. 2. Two model non-native fishes, the globally invasive Cyprinus carpio and Carassius auratus, and the model native fish Tinca tinca, were used in a pond experiment to test how increased intra- and inter-specific competition influenced trophic niches and somatic growth rates. This was complemented by samples collected from three natural fish communities where the model fishes were present. The isotopic niche, calculated using stable isotope data, represented the trophic niche. 3. The pond experiment used additive and substitutive treatments to quantify the trophic niche variation that resulted from intra- and inter-specific competitive interactions. Although the trophic niche sizes of the model species were not significantly altered by any competitive treatment, they all resulted in patterns of inter-specific niche divergence. Increased inter-specific competition caused the trophic niche of T. tinca to shift to a significantly higher trophic position, whereas intra-specific competition caused its position to shift towards elevated 13C. These patterns were independent of impacts on fish growth rates, which were only significantly altered when inter-specific competition was elevated. 4. In the natural fish communities, patterns of trophic niche partitioning between the model fishes was evident, with no niche sharing. Comparison of these results with those of the experiment revealed the most similar results between the two approaches were for the niche partitioning between sympatric T. tinca and C. carpio. 5. These results indicate that trophic niche divergence facilitates the integration of introduced species into food webs, but there are differences in how this manifests between introductions that increase inter- and intra-specific competition. In entirety, these results suggest that the initial ecological response to an introduction appears to be a trophic re-organisation of the food web that minimises the trophic interactions between competing species

Nuevo Macrocystellidae (Echinodermata, Cystoidea Rhombifera) para el Ordovícico español.

Se describe un ejemplar de Macrocystella Callaway, 1877, procedente del Caradoc de El Viso del Marqués, provincia de Ciudad Real. El género Macrocystella es el único descrito para la familia Macrocystellidae y se trata de un taxón de especial interés al ser considerado uno de los Glyptocystitida más primitivos de los que derivarían los rombíferos con pectinirrombos. El género estaba hasta la fecha restringido al Ordovícico inferior y medio, resultando ser éste el primer hallazgo incuestionable de Macrocystella en materiales de edad Ordovícico superior; siendo, por otro lado, la primera especie que se describe para España, la cual proponemos denominar Macrocystella pauli. [ABSTRACT] A new species of Macrocystella Callaway, 1877, based on a specimen, from the Caradoc of El Viso del Marqués (Ciudad Real province, Spain) is described and named Macrocystella pauli. The family Macrocystellidae contains only the one genus Macrocystella which is considered to be the most primitive glyptocystitid from which later rhombiferans with pectinirhombs were derived. This paper presents the first record of Macrocystella from Spain and the first undoubted record from the Upper Ordovician

CoordMaude Simplifying Formal Coordination Specifications of Cooperation Environments

AbstractDeveloping concurrent applications in cooperative environments is an arduous task. This is mainly due to the fact that it is very difficult to specify the synchronized interaction between the entities composing the system. Using coordination models makes this task easier. The latest trends in this area suggest that to manage the successful implementation of complex systems, coordination models must support some key features regarding the coordination constraints: their separated specification, their unanticipated evolution and their dynamic change. However, supporting these features is not only a technical challenge: it must be also guaranteed that the application of a separately specified coordination pattern to a set of encapsulated entities, or the change of the coordination constraints in an already running software system will not produce semantic errors. This is just the problem focused in this paper. In particular, a method for generating formal interpretable specifications reproducing coordinated environments is presented. The method is based on the Coordinated Roles coordination model and makes use of Maude as a formal language. The benefits obtained are: (i) easy specification using the coordination model syntax, (ii) automatic generation of the corresponding formal specification and (iii) simulation of system behaviour

Long-term dynamics of shrub facilitation shape the mixing of evergreen and deciduous oaks in Mediterranean abandoned fields

Recovery of Mediterranean forests after field abandonment is a slow process, even without propagule limitations. This is mainly due to stressful conditions for seedling establishment. In this context, shrubs play a critical role in facilitating tree recruitment, but how this process unfolds after field abandonment is not entirely known. We evaluated the long-term dynamics of facilitation by the nurse shrub Retama sphaerocarpa in the recruitment of two ecologically contrasting oaks, the evergreen Quercus ilex and the deciduous Quercus faginea. Thirty years after field abandonment, we dated shrubs and oak established in an old field to estimate the annual recruitment rates and investigate temporal recruitment patterns. For oaks, we differentiated recruitment at each microsite (i.e., open or under shrub). To assess how nurse shrubs modulated environmental stressors, we modelled oak recruitment as a function of climatic variables. For the evergreen oak, we assessed these effects within each microsite. Finally, we estimated the annual interaction index between shrubs and oak juveniles as a function of climatic conditions