238 research outputs found

    Superconducting BSCCO Ceramics as Additive to the Zinc Electrode Mass in the Rechargeable Nickel-Zinc Batteries

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    The electronic conductivity of the main component of the zinc electrode in the rechargeable zinc-nickel battery – ZnO,  is rather poor and this is the main reason for the electrochemical heterogeneity of the anode mass and the loss of active surface area during charge/discharge cycling with a corresponding negative effect on the electrode characteristics In the present work, the possibility of application of superconductive cuprate Bi-Pb-Sr-Ca-Cu-O (BSCCO) ceramic as a multifunctional conductive additive to the zinc electrode mass is studied. Powder samples of the BSCCO ceramic Bi1,7Pb0,3Sr2Ca2Cu3Ox are produced by two-stage solid-state synthesis and they are physicochemically characterized. The XRD patterns and SEM observation reveal a well crystallized single phase of superconducting 2212 BSCCO system with average crystallite size 5-10 µm. The chemical stability of BSCCO ceramics in highly alkaline medium of the Ni-Zn battery is confirmed by structural and morphological analysis (XRD, SEM and EDX) of the samples before and after prolong exposure (96 h) to 7M KOH. The electrochemical tests are carried out by a specially designed prismatic alkaline Ni-Zn battery cell with conventional sintered type nickel electrodes and pasted zinc electrode with active electrode mass based on ZnO (88 wt.%) and addition of BSCCO powder or acetylene black as conductive additives. The study show that the zinc electrode with BSCCO superconducting ceramic additive exhibits very good cycleability, remarkable capacity stability and much higher discharge capacity at prolong charge/discharge cycling in comparison to the  zinc electrode with the “classic” carbon conductive additive. It is suggested that the addition of BSCCO ceramics improves not only conductivity of the electrode mass and reduces the gas evolution but also stabilizes porosity structure. The results obtained prove the possibility of application of superconducting BSCCO ceramics as a multifunctional additive to the active mass of the zinc electrodes for alkaline battery systems

    Effects of local activation times on the tension development of human cardiomyocytes in a computational model

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    The human heart is an organ of high complexity and hence, very challenging to simulate. To calculate the force developed by the human heart and therefore the tension of the muscle fibers, accurate models are necessary. The force generated by the cardiac muscle has physiologically imposed limits and depends on various characteristics such as the length, strain and the contraction velocity of the cardiomyocytes. Another characteristic is the activation time of each cardiomyocyte, which is a wave and not a static value for all cardiomyocytes. To simulate a physiologically correct excitation, the functionality of the cardiac simulation framework CardioMechanics was extended to incorporate inhomogeneous activation times. The functionality was then used to evaluate the effects of local activation times with two different tension models. The active stress generated by the cardiomyocytes was calculated by (i) an explicit function and (ii) an ode-based model. The results of the simulations showed that the maximum pressure in the left ventricle dropped by 2.3% for the DoubleHill model and by 5.3% for the Lumens model. In the right ventricle the simulations showed similar results. The maximum pressure in both the left and the right atrium increased using both models. Given that the simulation of the inhomogeneously activated cardiomyocytes increases the simulation time when used with the more precise Lumens model, the small drop in maximum pressure seems to be negligible in favor of a simpler simulation model

    Magneto-Optical and Multiferroic Properties of Transition-Metal (Fe, Co, or Ni)-Doped ZnO Layers Deposited by ALD

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    ZnO doped with transition metals (Co, Fe, or Ni) that have non-compensated electron spins attracts particular interest as it can induce various magnetic phenomena and behaviors. The advanced atomic layer deposition (ALD) technique makes it possible to obtain very thin layers of doped ZnO with controllable thicknesses and compositions that are compatible with the main microelectronic technologies, which further boosts the interest. The present study provides an extended analysis of the magneto optical MO Kerr effect and the dielectric properties of (Co, Fe, or Ni)-doped ZnO films prepared by ALD. The structural, magneto optical, and dielectric properties were considered in relation to the technological details of the ALD process and the corresponding dopant effects. All doped samples show a strong MO Kerr behavior with a substantial magnetization response and very high values of the Kerr polarization angle, especially in the case of ZnO/Fe. In addition, the results give evidence that Fe-doped ZnO also demonstrates a ferroelectric behavior. In this context, the observed rich and versatile physical nature and functionality open up new prospects for the application of these nanostructured materials in advanced electronic, spintronic, and optical devices

    Epsilon iron oxide: Origin of the high coercivity stable low Curie temperature magnetic phase found in heated archeological materials

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    The identification of epsilon iron oxide (-Fe2O3) as the low Curie temperature high coercivity stable phase (HCSLT) carrying the remanence in heated archeological samples has been achieved in samples from two archeological sites that exhibited the clearest evidence of the presence of the HCSLT. This uncommon iron oxide has been detected by Confocal Raman Spectroscopy (CRS) and characterized by rock magnetic measurements. Large numbers of -Fe2O3 microaggregates (in CO) or isolated clusters (in HEL) could be recognized, distributed over the whole sample, and embedded within the ceramic matrix, along with hematite and pseudobrookite and with minor amounts of anatase, rutile, and maghemite. Curie temperature estimates of around 170 degrees C for CO and 190 degrees C for HEL are lower than for pure, synthetic -Fe2O3 (227 degrees C). This, together with structural differences between the Raman spectra of the archeologically derived and synthetic samples, is likely due to Ti substitution in the -Fe2O3 crystal lattice. The -Fe2O3--Fe2O3--Fe2O3 transformation series has been recognized in heated archeological samples, which may have implications in terms of their thermal history and in the factors that govern the formation of -Fe2O3

    Further progress in the study of epsilon iron oxide in archaeological baked clays

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    [EN] The occurrence of ε-FeO in archaeological samples that have been subjected to high temperatures is gradually being detected by the use of micrometric structural characterization techniques. This work provides new information by revealing that the ε-FeO is formed as a response to temperature, the aggregation state and the position within the baked clay with respect to the nearest heat source. In addition, depending mainly on the atmospheric environment, the temperature reached by the combustion structure, the distance from the heating source and the particle aggregation, other iron oxide magnetic phases are produced. In the baked clay studied here, hematite is found over the whole range of samples studied but its magnetic contribution is negligible. Magnetite is observed at the sample surface, probably due to local atmospheric environment closest to the combustion source. Maghemite is found at all depths up to 6 cm below the sample surface. ε-FeO has a limited distribution, found within 2–3 cm of the sample surface. Furthermore, the viability of this compound as a palaeofield marker has been evaluated in both archaeological and synthetic samples. The results indicate that ε-FeO is able to register the direction of the magnetic field. Linear palaeointensity plots have been obtained in synthetic samples, although the value of the palaeofield could be, sometimes, overestimated.The authors also acknowledge the financial support from the Spanish Ministry of Science, Innovation and Universities under the projects RTI2018-095856-B-C21, CGL2017-87015-P, CGL2017-92285-EXP, CGL2017-92285-EXP/BTE, MAT2017-86540-C4-1-R, MAT2017-87072-C4-2-P and RTI2018-095303-A-C52, from Comunidad de Madrid NANOFRONTMAG S2013/MIT-2850 and NANOMAGCOST S2018/NMT-4321, and from the European Commission under H2020 frame by AMPHIBIAN Project ID: 720853. APO thanks the Ministry of Economy, Industry and Competitiveness (PTA Contract).Peer reviewe

    Perinatal depression in the Spanish context: consensus report from the general council of psychology of Spain

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    Background: Perinatal depression is a major public health problem, with an estimated prevalence of approximately 15% during the first postpartum year. Despite the high prevalence of postpartum depression, there is no consensus regarding assessment and treatment in the Spanish context. The General Council of Psychology of Spain convened a working group of experts in the field, including both academics and healthcare professionals, to review and propose recommendations based on evidence and best practices that could be applied in the Spanish context. Method: A literature search was completed in various databases (e.g., Medline, PsychInfo) including a combination of terms related to peripartum depression (PPD) assessment and diagnosis, prevention, treatment, and cost-effectiveness. A narrative synthesis of the literature has been conducted together with a critical overview of PPD with a special focus on the Spanish context. Results: In this consensus report, developing questions including prevalence and assessment tools, comparative effectiveness of preventive and treatment interventions, and cost-effectiveness of PPD management have been analyzed. Conclusions: The General Council of Psychology of Spain network advocates the establishment of compulsory screening protocols in all the autonomous regions. Also, it is necessary to promote the inclusion in maternal education of programs for the promotion of mental well-being and selective/indicated prevention carried out by a psychology professional with specialized training in the area. This consensus document also promotes the presence of a psychology professional with specialized training in the area. Antecedentes. La depresión perinatal es un importante problema de salud pública, con una prevalencia estimada de aproximadamente el 15% durante el primer año posparto. A pesar de la gran prevalencia de depresión posparto (DPP), no existe consenso sobre la evaluación y el tratamiento en el contexto español. El Consejo General de Psicología de España convocó a un grupo de trabajo de expertos en la materia, tanto académicos como profesionales sanitarios, para revisar y proponer recomendaciones basadas en evidencias y mejores prácticas que puedan aplicarse en el contexto español. Método. Se realizó una búsqueda bibliográfica en varias bases de datos (p. ej., Medline, PsychInfo) que incluía una combinación de términos relacionados con la evaluación y el diagnóstico de la DPP, prevención, tratamiento y coste-eficacia. Se ha realizado una síntesis narrativa de la literatura junto con una visión crítica de la DPP con un enfoque especial en el contexto español. Resultados. Las preguntas de desarrollo que incluyen prevalencia y herramientas de evaluación, la eficacia comparativa de las intervenciones preventivas y de tratamiento y la relación coste-efectividad de la gestión de la PPD se han analizado en este informe de consenso. Conclusiones. La red del Consejo General de Psicología de España aboga por el establecimiento de protocolos obligatorios de cribado en todas las Comunidades Autónomas. Asimismo, es necesario promover la inclusión en la educación materna de programas de promoción del bienestar mental y la prevención selectiva indicada llevadas a cabo por un profesional de la psicología con formación especializada en el área
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