Power-Integrated Circuit Active Leakage Current Detector

Most of the failures of induction motors become insulation faults, causing a permanent damage. Using differential current transformers, a system capable of insulation fault detection was developed, based on the differential relay protection scheme. Both signal injection and fault detection circuitry were integrated in a single chip. The proposed scheme is faster than other existing protection and not restricted to protect induction motors, but several other devices (such as IGBTs) and systems. This paper explains the principle of operation of fault protection scheme and analyzes an integrated implementation through simulations and experimental results. A power-integrated circuit (PIC) implementation is presented.Fil: Bulacio, M. F.. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Electronica; ArgentinaFil: González, Tomás Andrés. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Electronica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marinelli, Guido. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Electronica; ArgentinaFil: Alonso, Ramiro. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Electronica; ArgentinaFil: Tacca, Hernán Emilio. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Electronica; Argentin

Oblique basin inversion and strain partitioning in back-arc context: example from the Moroccan Alboran Margin (Western Mediterranean)

EUROPEAN GEOPHYSICAL UNIO

The role of afforestation species as a driver of Hg accumulation in organic horizons of forest soils from a Mediterranean mountain area in SW Europe

Forest areas are a primary sink of atmospheric mercury (Hg) within terrestrial ecosystems, whereas forest vegetation plays a key role in atmospheric Hg transfer to soil horizons. This study assessed variations in total Hg contents (HgT) and accumulation (HgRes) in the soil organic horizons of a forest area in NE Portugal, where post-wildfire afforestation led to the substitution of the native deciduous species (Quercus pyrenaica) by fast-growing coniferous species (Pseudotsuga menziesii and Pinus nigra). The study also evaluated, for each species, the links between Hg contents and other biophilic elements of soil organic matter (C, N, S) present in organic subhorizons (OL, OF, OH). Mean HgT in the organic horizons of the different tree species follow the sequence: P. nigra (88 μg kg−1) < Q. pyrenaica (101 μg kg−1) < P. menziesii (141 μg kg−1). The highest HgRes for the entire organic horizon was found under P. menziesii (471 μg m−2), followed by P. nigra (253 μg m−2) and Q. pyrenaica (189 μg m−2). Among the organic subhorizons, values of HgT and HgRes follow the sequence OL < OF < OH, which is consistent with the degree of organic matter humification. Indeed, HgT and HgRes correlated significantly with the C/N and C/S ratios for all species and organic subhorizons, suggesting that the quality of organic matter may influence strongly the Hg fate in these forest soils. Soils from P. menziesii plots have shown an HgRes 2.5 times higher than in plots dominated by the native Q. pyrenaica. Hg accumulation in the organic horizons, promoted in the coniferous species, may increase the risk of Hg mobilization due to wildfires and forest management practices. Therefore, forest management plans should select cautiously the tree species for afforestation in order to minimize adverse environmental effects caused by changes in the biogeochemical cycle of contaminants such as Hg.M. Méndez-López acknowledges the predoctoral grant FPU of Ministerio de Educación y Formación Profesional (FPU17/05484). It is also recognized the financial support of the Consellería de Cultura, Educación e Universidade (Xunta de Galicia) through the contract ED431C 2021/46-GRC granted to the research group BV1 of the University of Vigo and the research project ED431F2018/06-EXCELENCIA.info:eu-repo/semantics/publishedVersio

Morphological characterization of contourite and mass-wasting recent processes at the Guadalquivir Bank Margin uplift, Gulf of Cádiz

The Gulf of Cadiz records the interplay of a variety of sedimentary processes related to the circulation of water masses. The most important one is the Mediterranean Outflow Water (MOW) that exits the Mediterranean Sea, but other water masses also affect the seafloor, with complex variations along time and space. This work studies the interplay between oceanographic and gravitational sedimentary processes on the Guadalquivir Ridge, based on bathymetry and high-resolution seismic profiles. A series of morphological features including flat terraces, circular/elliptical depressions, semicircular scarps and valley-shaped features are analysed in order to better understand the interaction between water masses circulation and mass-wasting processes of the Gulf of Cadiz.Versión del edito

Interacción entre procesos sedimentarios longitudinales y transversales en el Mar de Alborán durante el Plioceno y Cuaternario

Several morphosedimentary signatures produced by the interaction between alongslope and downslope sedimentary processes have been identified in the Pliocene and Quaternary records as well as on the present-day seafloor of the Alboran Sea. The scenarios of interaction move between two-end-members: from bottom currents dominating gravity flows to gravity flows dominating contour currents. In between these extreme cases, the alternation and balancing of both processes can occur; bottom current activity influencing the gravity flows has been also detected. Although interaction occurs in the Spanish and Moroccan margins, it is especially complex and varied on the Spanish margin, with regional and local effects on the turbidite systems. In contrast, the interaction on the Moroccan margin primarily inhibits the formation of canyons and related fan lobe deposits.Versión del edito

Modelización de los end-members para reconocer fuentes de aporte sedimentario en contornitas: un caso de estudio en el Mar de Alborán

Contourite drifts are one the main morphosedimentary features in the Alboran Sea and their sediments are important archives of the past oceanographic conditions and sedimentary processes. The end-member modelling approach lets to decompose multimodal grain-size distribution into genetically meaningful subpopulation that may be related to different sediment transport mechanisms and source areas. Three end-members have been identified in the contourite drift and moat system located at the southern side of the Dijbouti Ville seamount that have been interpreted in terms of sediment sources. Two end-members point to an eolian source and comprise fine silt (EM1) and coarse silt (EM2) as modal grain-sizes, characterized by high and low contents, respectively, of terrigenous elements (Al, Si, Ti and K). The third end-member (EM3) indicates a fluvial origin and is mainly defined by a clay modal grain-size of intermediate and homogeneous content in terrigenous elements. Downcore variation of the relative proportion of these EMs can be used to decipher paleocenographic and paleoclimatic conditions in the Alboran Sea.Versión del edito

Detailed analysis of the interaction between alongslope and downslope sedimentary processes in the Alboran Sea during the Pliocene and Quaternary

This work aims to analyze the interaction between alongslope contouritic and downslope gravitational processes in the Alboran Sea. Recent results (Juan et al., 2012, 2016) demonstrated that the Pliocene and Quaternary stratigraphic architecture is mostly made up the vertical stacking of contourites interrupted by turbidite systems (TSs). The accurate analysis of all available seismic profiles has revealed several morpho-sedimentary signatures produced by the interaction of the Atlantic Water (AW) and Mediterranean waters (MWs) with the gravity flows in the Pliocene and Quaternary sedimentary record, as well as on the present-day seafloor. Different levels of interaction have been identified and they move between two-end-members: from bottom currents dominating gravity flows, to gravity flows dominating bottom currents. In between these extreme cases, a range of possibilities can occur. First, downslope and alongslope processes can alternate, with vertical and cyclic stacking of both types of deposit. Second, these processes can be balanced, allowing the simultaneous outbuilding of contourites and gravity flow deposits. Last, bottom currents can influence gravity flows. This last interaction is the most common in the Alboran Sea, resulting in the migration of the fan deposits in the direction of the dominant current, and also with effects on the architecture of the turbidite fans, and on their sedimentary composition (grain size). The different levels of interaction change in space and time. These changes have controlled the different depositional architecture displayed by the Spanish and Moroccan margins and the lateral changes along the Spanish margin as a consequence of the different architecture of the turbidite systems. Although interaction occurs in both margins, it is especially complex and varied on the Spanish margin, where the alongslope action is related to the AW, the light intermediate and the dense deep Mediterranean waters (LMw and DMw, respectively). This complex interaction has resulted in a depositional architecture that changes laterally as a consequence of the different architecture of the turbidite systems. Contrasting, on the Moroccan margin the alonsglope action is dominant, being mainly governed by the energy of the AW and the WMDW, that primarily inhibits the formation of canyons and related fan lobe deposits. This inhibition has been interpreted to be result of the topographical acceleration of the WMDW core that would favour an intense alongslope sediment transport, preventing deposition, avoiding the convergence of sediment, and thus inhibiting the formation of downslope gravity flows

Active faulting and earthquakes in the central Alboran Sea

Central Alboran Sea constitutes a key area to analyze the relationships between active tectonic structures and moderate seismicity. The heterogeneous crustal layered structure and the propagation of the deformation along the fault zones are key features to relate active faults and seismic hazard. The NW-SE oblique convergence between Eurasian and African plates determines the broad band of tectonic deformation and seismicity along the Alboran Sea basin (westernmost Mediterranean). The Betic-Rif Cordilleras are connected through the Gibraltar Arc and surround the Alboran Sea formed by thinned continental crust. This basin is filled since the Neogene by sedimentary and volcanic rocks. Central Alboran Sea is now undergoing shortening and is mainly deformed by a system of conjugated WNW-ESE dextral and NE-SW sinistral faults with recent activity formed by indenter tectonics related to a heterogeneous crustal behavior. In addition a NNW-SSE normal fault set and large ENE-WSW folds deform the central and northern Alboran Sea. These structures support a present-day N160 E maximum compression and orthogonal extension. In this setting, most of the recent seismicity is concentrated along a NNE-SSW zone that extends landward from Campo de Dalias (SE Spain) to Al Hoceima (Morocco). The Campo de Dalias 1993-1994 seismic crisis reached up to magnitudes Mw= 5.3, while the Al Hoceima area was affected by seismic crisis of 1994 (May 26, Mw=5.6) and 2004 (Feb 24, Mw= 6.4). The main active fault related to the 2004 earthquakes, even that it was a vertical NNE-SSW oriented fault and focal depth was 6 km, did not reach the surface probably due to the presence of a mechanically layered crust. The main active surface faults located in Al Hoceima area (the NNE-SSW transtensional sinistral Trougout fault zone) extended northwards towards the NE-SW sinistral Al Idrissi Fault that intersects the Alboran Sea and are connected with the normal NNW-SSE Balanegra Fault zone. Although these active faults determine most of the seismicity of the central Alboran Sea, the seismic crisis that occurred since January 2016, reaching Mw= 6.3 is located in a region westward of Al Idrissi Fault, underlining the relevance of growth of new faults to determine the seismic hazard of the region. Earthquake focal mechanisms support that the main active fault has a NNE-SSW orientation, similar to Al Idrissi Fault zone. Maximum magnitude suggests a surface rupture length of at least 12 km and a subsurface rupture of 20 km. Propagation of a new fault is more efficient to accumulate elastic deformation, and to produce highest magnitude earthquakes than already formed faults. This new fault is connected probably in deep crustal levels with the blind sinistral fault responsible of the 2004 Al Hoceima earthquake. The tsunami hazard of the region should be consequence of both seabottom displacement due to fault activity and co-seismic submarine landslides. The INCRISIS cruise, scheduled by May 2016, will provide evidences of seabottom effects of this seismic crisis

Palaeoceanographic implications of current-controlled sedimentation in the Alboran Sea after the opening of the Strait of Gibraltar

This study focuses on the Alboran Sea area (Westernmost Mediterranean), where a seismic analysis of the Pliocene and Quaternary stratigraphy was conducted in the Alboran Sea (Westernmost Mediterranean) using ~2000 profiles consisting of single and multi-channel seismic records. The seismic facies and architectural analysis of the deposits evidence the presence of bottom-current deposits (plastered, sheeted, elongated-separated and confined monticular drifts) and associated erosive features (terraces, scarps, moats and channels). Many of these deposits were previously considered to be open slope turbidite deposits which have now been reinterpreted as contourites.The contourite features have developed under the continuous influence of Mediterranean water masses, after the opening of the Strait of Gibraltar (roughly divided into light and dense Mediterranean waters), with plastered drifts dominating on the Spanish and Moroccan continental slopes, and sheeted drifts infilling the subbasins. The location and growth of contourite features have been mainly controlled by two main factors: i) tectonics, which has governed the relocation of the main pathways of the water masses; and ii) climate, which has influenced both water mass conditions and the depth of interfaces, as well as hinterland sediment sources, conditioning the morphoseismic characteristics of the drifts (facies and geometry) and terrace formation (dimensions). The mapping of the contourite facies through time has allowed defining three main scenarios for deep water circulation since the opening of the Strait of Gibraltar, which are: i) Atlantic Zanclean flooding; ii) the Pliocene sea, with two different stages caused by the progressive relocation of flow pathways; and iii) the Quaternary sea, with well defined characteristics and mostly stable flow pathways for the AW, and light and dense Mediterranean waters.This work lead us to consider the geologic framework characterizing the Alboran Sea may have played an important role in the interaction of the Mediterranean Waters before entering the Strait of Gibraltar, and thus in forming the MOW. Additionally, the results of this work may help in understanding the sedimentation in other Mediterranean margins affected by the same water masses and other partly land-locked basins with exchanges of waters over a confining sill