3,287 research outputs found

    Power Factor Corrector Design applied to an 85-kHz Wireless Charger

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    Wireless charging technology extends the battery autonomy by allowing more flexible and practical ways of recharging it even when the electric vehicle is on move. The frequency conversion, which is required to generate a kHz-ranged magnetic field, also leads to considerable harmonics. As a result, the power factor and the corresponding efficiency decrement. This paper proposes a Power Factor Corrector which overcomes this drawback. The most relevant feature of the designed Power Factor Corrector is that it does not need any electrical signal from the secondary side to adjust its operation properly. The simulation results show the ability of the proposed scheme to increment the system efficiency for different State-Of-Charge in the Battery.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Independent primary-side controller applied to wireless chargers for electric vehicles

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    Electric vehicles rely on batteries that need to be frequently recharged. As an alternative to conductive charging, wireless chargers provide a higher reliability to pollution and electric failures and they also extend the situations and places where the recharge could be available without user’s intervention (e.g. parking spaces, on-road). In order to optimize the performance of a wireless charger, its configuration should be dynamically adapted to the varying battery’s electrical features. Towards this goal, controllers are incorporated into the system to modify the behavior of some switching devices belonging to the power electronics blocks. This paper presents a controller that acts in the DC/DC structure placed in the primary side. As a novelty, the controller infers the instantaneous battery power demands by exclusively measuring voltage and current in the primary side. In this way, there is no need for communicating (via wired or wireless links) the primary and the secondary sides. The simulation results show the ability of the controller to adapt to different battery states.Universidad de Málaga. Campus de Excelencia Internacional Andalucia Tec

    Sensitivity analysis of Component's Tolerance in Inductively Coupled Power Transfer System

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    ICPT systems help drivers to recharge their electrical vehicles via wireless. The core of the system is a pair of coils and two reactive structures. In order to predict the performance of a practical implementation, it is necessary to study the impact of using real components which suffer from variations in their nominal values. Basing on the performed study, we conclude that the components on the side where the inductance is in series with the capacitance should be carefully selected as variations in their values greatly affect the system performance. A 50 kW system has been evaluated in terms of efficiency and load voltage.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Innovations that empower teachers: the case of i-Spring to design tailor-made learning materials.

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    Organizations must acknowledge the necessity of change and adopt diverse management strategies to swiftly adapt to the evolving technology and the new knowledge landscape. In the context of educational changes, an increasing value is placed nowadays on identifying renewed and effective approaches to teaching as the safest way to bring about not just students’ learning but growth, development and/or evolution. The strengthened emphasis on innovation as key to progress in today’s world has resulted in a widespread encouragement for teachers to pursue innovative initiatives that, in turn, will empower them. So, innovation practices will help those teaching practitioners who implement them to become increasingly empowered, and teacher empowerment is an essential tool for carrying out educational innovations. Notwithstanding this, each innovation, whatever the generation it belongs to, requires new knowledge, understanding, and skills and can therefore be perceived as demanding or even a bit intimidating, particularly technology-based ones.Plan Propio Integral de Docencia de la Universidad de Málaga. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Staphylococcus aureus Carriage in the Nasotracheal Cavities of White Stork Nestlings (Ciconia ciconia) in Spain: Genetic Diversity, Resistomes and Virulence Factors

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    The molecular ecology of Staphylococcus aureus in migratory birds (such as white storks) is necessary to understand their relevance in the “One Health” ecosystems. This study determined the nasotracheal carriage rates of S. aureus from white storks in Southern Spain and genetically characterized the within-host diversity. A collection of 67 S. aureus strains, previously obtained from 87 white stork nestlings (52 nasal and 85 tracheal samples) fed by their parents with food foraged in natural and landfill habitats, were tested for their antimicrobial resistance (AMR) phenotypes. Moreover, the AMR genotypes, immune evasion cluster (IEC), virulence genes and the detection of CC398 lineage were studied by PCR. The spa types and multilocus-sequencing-typing (MLST) were also determined by PCR and sequencing. Staphylococcus aureus carriage was found in 31% of storks (36.5%/11.9% in nasal/tracheal samples). All isolates were methicillin-susceptible (MSSA) and 8.8% of them were also susceptible to all tested antibiotics. The AMR phenotype/percentage/genes detected were as follows: penicillin/79.1%/blaZ; erythromycin-clindamycin-inducible/19.1%/ermA, ermT; tetracycline/11.9%/tetK; clindamycin/4.5%/lnuA and ciprofloxacin/4.5%. Twenty-one different spa types, including 2 new ones (t7778-ST15-CC15 and t18009-ST26-CC25), were detected and ascribed to 11 clonal complexes (CCs). MSSA-CC398 (8.2%), MSSA-CC15 (7.1%) and MSSA-ST291 (5.9%) were the most prevalent lineages in storks. Moreover, tst-positive (MSSA-CC22-t223 and MSSA-CC30-t1654), eta-positive (MSSA-CC9-t209) and etb-positive strains (MSSA-CC45-t015) were detected in four storks. The 18.5% of storks harboured distinct MSSA strains (with different lineages and/or AMR genes). Nestlings of storks foraging in landfills (10 CCs) had more diverse S. aureus strains than those of parents foraging in natural habitats (3 CCs). Low level of AMR was demonstrated among S. aureus strains. The predominance of MSSA-CC398 (an emergent clade) and toxigenic MSSA strains in stork nestlings highlight the need for continuous surveillance of S. aureus in wild birds.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.This work was financed by MCIN/AEI/10.13039/501100011033 of Spain. Also, it received funding from the European Union’s H2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement N° 801586. It was supported by project SBPLY/19/180501/000325 of the regional government of Castilla – La Mancha by the European Union’s funds for regional development (FEDER).Peer reviewe

    Study of the crystallization in fast sintered Na-rich plagioclase glass-ceramic

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    A dense, ∼94% of crystalline phase, glass-ceramic based on Na-rich plagioclase feldspar crystallizations has been obtained by a fast sintering process for the first time. By using Sr2+ and Ca2+ as nucleating agents, a unique hierarchical micro-nanostructure is developed in a fast sintering process at 1220 °C. In this work, a thorough study about crystallization processes of this novel material has been extensively carried out through thermal quenching experiments and supported by DTA/TG, Hot stage microscopy, XRD, FE-SEM, TEM/HRTEM and XPS measurements. The study reveals that crystallization takes place in two steps during the sintering process. Microcrystals nucleate on heating at temperatures >900 °C, while nanocrystals start nucleating at the dwelling temperature, 1220 °C. However, it is during holding and cooling time when nanostructures zones grow, and the unique highly crystalline micro-nanostructure is developed. Structural and compositional analysis supported by NMR, shows the main presence of Q4(nAl) albite-like sites and in lesser extent anorthite-like sites, corroborating the formation of a sodic plagioclase structure. The analysis of Si neighbours indicates that chemical environment presents a slight Si/Al disorder at short range.The authors express their thanks to the MINECO project MAT2017- 86450-C4-1-R, and project CDTI of CTV for their financial support. Dra. E. Enriquez is also indebted to MINECO for a ‘‘Torres Quevedo’’ contract (ref: PTQ-14-07289), which is co-financed with European Social Funds

    Design and development of complex phase steels with improved combination of strength and stretch-flangeability

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    This study presents the design and development of a hot-rolled bainitic steel, presenting a good combination of strength and stretch-flangeability, for automotive applications. Ti, Nb, and Mo were added in the steel composition in order to control austenite grain sizes, enhance precipitation hardening, and promote the formation of bainite. This study focuses on the effect of process parameters on final microstructures and mechanical properties. These parameters are the finishing rolling temperature, which conditions the austenite microstructure before its decomposition, and the coiling temperature, which conditions the nature and morphology of the ferritic phases transformed. A preliminary study allowed to determine the austenite grain growth behavior during reheating, the recrystallization kinetics, and the continuous cooling transformation curves of the studied steel. Then, a first set of parameters was tested at a semi-industrial scale, which confirmed that the best elongation properties were obtained for homogeneous bainitic lath/granular microstructures, that can be produced by choosing a coiling temperature of 500 °C . When choosing those parameters for the final industrial trial, the microstructure obtained consisted of a homogeneous lath/granular bainite mixture that presented a Ultimate Tensile Strength of 830 MPa and a Hole Expansion Ratio exceeding 70%.Peer ReviewedPostprint (published version

    Nasotracheal Microbiota of Nestlings of Parent White storks with Different Foraging Habits in Spain

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    Migratory storks could be vectors of transmission of bacteria of public health concern mediated by the colonization, persistence and excretion of such bacteria. This study aims to determine genera/species diversity, prevalence, and co-colonization indices of bacteria obtained from tracheal (T) and nasal (N) samples from storks in relation to exposure to point sources through foraging. One-hundred and thirty-six samples from 87 nestlings of colonies of parent white storks with different foraging habits (natural habitat and landfills) were obtained (84 T-samples and 52 N-samples) and processed. Morphologically distinct colonies (up to 12/sample) were randomly selected and identified by MALDI-TOF-MS. About 87.2% of the total 806 isolates recovered were identified: 398 from T-samples (56.6%) and 305 from N-samples (43.4%). Among identified isolates, 17 genera and 46 species of Gram-positive and Gram-negative bacteria were detected, Staphylococcus (58.0%) and Enterococcus (20.5%) being the most prevalent genera. S. sciuri was the most prevalent species from T (36.7%) and N (34.4%) cavities of total isolates, followed by E. faecalis (11.1% each from T and N), and S. aureus [T (6.5%), N (13.4%)]. Of N-samples, E. faecium was significantly associated with nestlings of parent storks foraging in landfills (p = 0.018). S. sciuri (p = 0.0034) and M. caseolyticus (p = 0.032) from T-samples were significantly higher among nestlings of parent storks foraging in natural habitats. More than 80% of bacterial species in the T and N cavities showed 1–10% co-colonization indices with one another, but few had ≥ 40% indices. S. sciuri and E. faecalis were the most frequent species identified in the stork nestlings. Moreover, they were highly colonized by other diverse and potentially pathogenic bacteria. Thus, storks could be sentinels of point sources and vehicles of bacterial transmission across the “One Health” ecosystems.This work was supported by the project PID2019-106158RB-I00 of the MCIN/AEI/10.13039/501100011033 of Spain and project SBPLY/19/180501/000325 of the regional government of Castilla—La Mancha co-financed by the European Union’s funds for regional development (Feder). Also, it received funding from the European Union’s H2020 research and innovation programme under the Marie Sklodowska-Curie grant agrrement No. 801586. J.P.-P. was supported by a postdoctoral grant Margarita Salas from the European Union – Next GenerationEU through the Complutense University of Madrid.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.Peer reviewe
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