Evaluation of a Local Fault Detection Algorithm for HVDC Systems

A great increase in the amount of energy generated from clean and renewable sources integrated in the electric power system is expected worldwide in the coming years. High Voltage Direct Current (HVDC) systems are seen as a promising alternative to the traditional Alternating Current (AC) systems for the expansion of the electric power system. However, to achieve this vision, there are some remaining challenges regarding HVDC systems which need to be solved. One of the main challenges is related to fault detection and location in HVDC grids. This paper reviews the main protection algorithms available and presents the evaluation of a local fault detection algorithm for DC faults in a multi-terminal Voltage Source Conversion (VSC) based HVDC grid. The paper analyses the influence of the DC voltage sampling frequency and the cable length in the performance of the algorithm. © 2019, European Association for the Development of Renewable Energy, Environment and Power Quality (EA4EPQ).The authors thank the support from the Spanish Ministry of Economy, Industry and Competitiveness (project ENE2016-79145-R AEI/FEDER, UE) and GISEL research group IT1083-16), as well as from the University of the Basque Country UPV/EHU (research group funding PPG17/23)

Exact solution of variable coefficient mixed hyperbolic partial differential problems

AbstractThis paper is concerned with the construction of exact series solution of mixed variable coefficient hyperbolic problems

Lecturas canónicas de Calderón en la primera mitad del siglo XIX

En este trabajo se analiza la diversidad de criterios con los que en la primera mitad del siglo XIX se valoró el teatro de Calderón y la diferente concepción de canónico o modélico que se atribuyó a su obra dramática. Se realiza así un recorrido explicativo de los comentarios que suscitó para comprobar cómo, cuándo y por qué se convirtió en un canon, en qué sentido se le canoniza (poético, dramático, ideológico, religioso, moral), y también cómo se transformó ese canon a lo largo del siglo XIX por razones tanto de evolución del arte como de la utilización de un autor representativo de la literatura española para justifi car el respeto a la tradición literaria nacional sobre la base de la aceptación de un sentido del progreso poético y político de las naciones. El artículo se inicia estudiando cómo la imaginación poética calderoniana se eleva a la categoría de cualidad nacional de índole artística o ético-religiosa según los críticos. Se continúa con los planteamientos que exigen su relativización estético-política en función de la historia y como ello conlleva una canonización moral. Ello plantea el conflicto entre la estatización del canon o su dinamización en la historia y por la historia.This study analyses the diversity of criteria with which the plays by Calderón were assessed during the first half of the 19th century, and the different classification as canon or model to which his dramatic works were ascribed. We present an explanatory review of the comments to which his works gave rise in order to observe how, when and why they became part of the canon, in what sense they were canonized (poetically, dramatically, ideologically, religiously, morally), and also how that canon was transformed throughout the 19th century. This transformation took place both on the grounds of the evolution of art and of the use of an author who was representative of Spanish literature to justify the respect for national literary tradition based on the acceptance of a sense of poetic and political progress of nations. The article starts by analysing how the poetic imagination of Calderón is granted the category of a national artistic or ethical/religious feature, according to the critics. It continues by studying the approaches that required its aesthetic/political relativization depending on history, and how this fact implies a moral canonization. This, in turn, leads to the conflict between a static canon and a canon which is dynamic as part of history and because of history

Resonant Raman scattering off neutral quantum dots

Resonant inelastic (Raman) light scattering off neutral GaAs quantum dots which contain a mean number, N=42, of electron-hole pairs is computed. We find Raman amplitudes corresponding to strongly collective final states (charge-density excitations) of similar magnitude as the amplitudes related to weakly collective or single-particle excitations. As a function of the incident laser frequency or the magnetic field, they are rapidly varying amplitudes. It is argued that strong Raman peaks should come out in the spin-density channels, not related to valence-band mixing effects in the intermediate states.Comment: Accepted in Physical Review

Development of a single tube multiplex real-time PCR to detect the most clinically relevant Mucormycetes species

AbstractMucormycetes infections are very difficult to treat and a delay in diagnosis could be fatal for the outcome of the patient. A molecular diagnostic technique based on Real Time PCR was developed for the simultaneous detection of Rhizopus oryzae, Rhizopus microsporus and the genus Mucor spp. in both culture and clinical samples. The methodology used was Molecular beacon species-specific probes with an internal control. This multiplex real-time PCR (MRT-PCR) was tested in 22 cultured strains and 12 clinical samples from patients suffering from a proven mucormycosis. Results showed 100% specificity and a detection limit of 1 fg of DNA per microlitre of sample. The sensitivity was 100% for clinical cultured strains and for clinical samples containing species detected by the PCR assay. Other mucormycetes species were not detected in clinical samples. This technique can be useful for clinical diagnosis and further studies are warranted

Distribution and origin of natural gas leakage in the Colorado Basin, offshore Argentina 2 Margin, South America: seismic interpretation and 3D basin modelling

The detailed analysis of a dense 2D seismic reflection dataset and data from 8 exploration wells, allowed us to identify, map out and characterize possible indications of past and present-day hydrocarbon leakage (i.e. gas chimneys, gas pockets, and seafloor mounds and pockmarks) on the continental shelf and slope of the Colorado Basin, offshore Argentina, where Permian, Jurassic and Early Cretaceous source rocks are potentially present and may be currently mature. Identified gas leakage features, developed both in the syn-rift and post-rift successions, were also analysed in relation to the structural the stratigraphic elements of the basin. A family of seabed pockmarks, located close to an array of submarine channels, was identified on the distal slope of the basin. These pockmarks are overlying a series of sub-vertical to vertical seismic chimneys in the subsurface. A calibrated basin-wide 3D petroleum system model comprising generation and migration of hydrocarbons was carried out and compared with the observations from the seismic analysis. Preliminary results from this model indicate that although synrift and early Cretaceous source rock (SR) intervals may be depleted in the central areas of the basin, an active kitchen from the Aptian SR may be present below the slope areas. Hydrocarbon migration pathways predicted by the 3D model (Hybrid method) coincide with the interpreted seismic chimneys underlying the observed seabed slope pockmarks. Hence, our results indicate that thermogenic gas may be currently generated in the distal slope of the basin from mature early post-rift source rocks within the Early Cretaceous (Aptian) sequences and migrates vertically, due to seal failure, through the stratigraphic column. This migrating thermogenic gas is feeding the seafloor pockmarks identified in the distal slope of the basin, although up-dip lateral migration along stratigraphic layers to the more proximal slope areas cannot be ruled out. The present work represents the first published study integrating detailed seismic analysis and 3D basin modelling linking observed gas-leakage indicators and associated seepage pathways, to their relative abundance, distribution and feeding systems offshore Argentina’s continental margin

Gold(I) complexes bearing alkylated 1, 3, 5-triaza-7-phosphaadamantane ligands as thermoresponsive anticancer agents in human colon cells

Overheating can affect solubility or lipophilicity, among other properties, of some an-ticancer drugs. These temperature-dependent changes can improve efficiency and selectivity of the drugs, since they may affect their bioavailability, diffusion through cell membrane or activity. One recent approach to create thermosensitive molecules is the incorporation of fluorine atoms in the chemical structure, since fluor can tune some chemical properties such as binding affinity. Herein we report the anticancer effect of gold derivatives with phosphanes derived from 1, 3, 5-triaza-7-phosphaadamantane (PTA) with long hydrocarbon chains and the homologous fluorinated chains. Besides, we analysed the influence of temperature in the cytotoxic effect. The studied gold(I) complexes with phosphanes derived from PTA showed antiproliferative effect on human colon carcinoma cells (Caco-2/TC7 cell line), probably by inhibiting cellular TrxR causing a dysfunction in the intracellular redox state. In addition, the cell cycle was altered by the activation of p53, and the complexes produce apoptosis through mitochondrial depolarization and the consequent activation of caspase-3. Furthermore, the results suggest that this cytotoxic effect is enhanced by hyperthermia and the presence of polyfluorinated chains. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

A role for SUMO modification in transcriptional repression and activation

Since the discovery of the SUMO (small ubiquitin-like modifier) family of proteins just over a decade ago, a plethora of substrates have been uncovered including many regulators of transcription. Conjugation of SUMO to target proteins has generally been considered as a repressive modification. However, there are now a growing number of examples where sumoylation has been shown to activate transcription. Here we discuss whether there is something intrinsically repressive about sumoylation, or if the outcome of this modification in the context of transcription will prove to be largely substrate-dependent. We highlight some of the technical challenges that will be faced by attempting to answer this question

A cohort study of post-weaning multisystemic wasting syndrome and PCV2 in 178 pigs from birth to 14 weeks on a single farm in England

Our hypothesis was that pigs that develop post-weaning multisystemic wasting syndrome (PMWS) are detectable from an early age with signs of weight loss and other clinical and serological abnormalities. Therefore, the objective of this study was to investigate the temporally varying and fixed events linked with the clinical incidence of PMWS by comparing affected and unaffected pigs in a cohort of 178 male piglets. Piglets were enrolled at birth and examined each week. Samples of blood were collected at regular intervals. The exposures measured were porcine circovirus type 2 (PCV2) antibody titres in all 178 and PCV2 antigen in a subset of 75 piglets. We also observed piglet health and measured their weight, and a post-mortem examination was performed by an external laboratory on all pigs between 6 and 14 weeks of age that died. From the cohort, 14 (8%) pigs died from PMWS and 4% from other causes. A further 37 pigs between 6 and 14 weeks of age died from PMWS (30) and ileitis and other causes (7). PMWS was only apparent in pigs from 1 to 2 weeks before death when they wasted rapidly. There were no other characteristic clinical signs and no obvious gross clinical lesions post-mortem. There was no strong link with PCV2 antibody throughout life but PCV2 antigen level was higher from 4 to 6 weeks of age in pigs that died from PMWS compared with pigs that died from other causes

Clustering analysis to improve total unit weight prediction from CPTu

Accurate estimates of soil unit weight are fundamental for correctly post process CPTu data and making use of Soil Behavior Type-based classification systems. Soil-specific and global regressions have been proposed for this purpose. However, soil-specific correlation might pose a problem of pertinence when applied at new sites. On the other hand, global correlations are easy to apply, but generally carry large systematic uncertainties. In this context, this work proposes a data clustering technique applied to geotechnical database aiming to identify hidden linear trends among dimensionless soil unit weight and normalized CPTu parameter according to some unobservable soil classes. Global correlations are then revisited according to such data subdivision aiming to improve accuracy of soil unit weight prediction while reducing transformation uncertainty. A new probabilistic criterion for soil unit weight prediction is also obtained. The potential benefits of the proposed procedure are illustrated with data from a Llobregat delta site (Spain).Postprint (published version