354 research outputs found

    Acid leaching of Al- and Ta-substituted Li7La3Zr2O12 (LLZO) solid electrolyte

    Get PDF
    Solid-state batteries (SSBs) are promising next-generation batteries due to their potential for achieving high energy densities and improved safety compared to conventional lithium-ion batteries (LIBs) with a flammable liquid electrolyte. Despite their huge market potential, very few studies have investigated SSB recycling processes to recover and reuse critical raw metals for a circular economy. For conventional LIBs, hydrometallurgical recycling has been proven to be able to produce high-quality products, with leaching being the first unit operation. Therefore, it is essential to establish a fundamental understanding of the leaching behavior of solid electrolytes as the key component of SSBs with different lixiviants. This work investigates the leaching of the most promising Al- and Ta-substituted Li7La3Zr2O12 (LLZO) solid electrolytes in mineral acids (H2SO4 and HCl), organic acids (formic, acetic, oxalic, and citric acid), and water. The leaching experiments were conducted using actual LLZO production waste in 1 M of acid at 1:20 S/L ratio at 25 ◩C for 24 h. The results showed that strong acids, such as H2SO4, almost completely dissolved LLZO. Encouraging selective leaching properties were observed with oxalic acid and water. This fundamental knowledge of LLZO leaching behavior will provide the basis for future optimization studies to develop innovative hydrometallurgical SSB recycling processes

    A Galerkin finite element method to solve fractional diffusion and fractional diffusion-wave equations

    Get PDF
    In the present study, numerical solutions of the fractional diffusion and fractional diffusion-wave equations where fractional derivatives are considered in the Caputo sense have been obtained by a Galerkin finite element method using quadratic B-spline base functions. For the fractional diffusion equation, the L1 discretizaton formula is applied, whereas the L2 discretizaton formula is applied for the fractional diffusion-wave equation. The error norms L 2 and L ∞ are computed to test the accuracy of the proposed method. It is shown that the present scheme is unconditionally stable by applying a stability analysis to the approximation obtained by the proposed scheme

    A Numerical Solution to Fractional Diffusion Equation for Force-Free Case

    Get PDF
    A collocation finite element method for solving fractional diffusion equation for force-free case is considered. In this paper, we develop an approximation method based on collocation finite elements by cubic B-spline functions to solve fractional diffusion equation for force-free case formulated with Riemann-Liouville operator. Some numerical examples of interest are provided to show the accuracy of the method. A comparison between exact analytical solution and a numerical one has been made

    Pleistocene eruptive chronology of the GölcĂŒk volcano, Isparta Angle, Turkey. Chronologie des Ă©pisodes volcaniques plĂ©istocĂšnes du volcan GölcĂŒk, Angle d’Isparta, Turquie

    Get PDF
    In the Eastern Mediterranean region, the Isparta volcanic belongs to the post-collisional alkali-potassic to ultrapotassic magmatism active since the Miocene in this part of the Anatolian peninsula from Afyon to Isparta. In the so-called Isparta Angle (IA) the magmatism is contemporaneous with an extensional regime intiated during Late Miocene and active throughout the Pliocene and Quaternary. Previous K/Ar dating performed on lavas suggested that potassic-ultrapotassic magmatism occurred between 4.7 to 4 Ma. However, a more recent (Quaternary) activity of the GölcĂŒk volcano is evidenced by the present-day morphology and field evidence although it remained undated and poorly studied so far. Field mapping and new radiometric data indicate that the main volcano-forming stages of the GölcĂŒk volcano consist of three main eruptives cycles. (1) Cycle I, represented by more than 200m-thick pyroclastic flow deposits occasionally separated by paleosoils and corresponding to caldera-forming ignimbritic eruptions. (2) Cycle II, consisting of tephriphonolite lava dome-flows extruded throughout the caldera and currently found along the rim of the present crater. (3) Cycle III made up of tuff-ring deposits related to several phreatoplinian eruptions of a maar-type volcanic activity. This youngest cycle ends with trachytic domes protruding within the maar crater. Unspiked 40K/40Ar dating on mesostasis was performed on lavas (tephriphonolites and trachytic domes), and complemented by preliminary 40Ar/39Ar data on tephra deposits (sanidine). Our preliminary results show that the entire activity of GölcĂŒk volcano took place during the Pleistocene and was disconnected from the older Pliocene volcanism. This volcanic activity can be considered as a new volcanic cycle, starting (Cycle I) around 200 ka with major explosive, regional-scale, events represented by at least six ignimbrites sheets. Cycle II occurred between 115 ± 3 ka to 62 ± 2 ka with probably some associated tephra deposits. Tuff-ring of Cycle III formed from 72.7 ± 4.7 ka to 24 ± 2 ka. The associated phreatoplinian eruptions have almost entirely destroyed the previously formed flow-dome. This latest activity corresponds to several volcanic crises as illustrated by the two domes protrusions separated by about 30 ka. The volcanic history of GölcĂŒk ceased around 24 ka ± 2 ka, but the periodicity of eruptive events appears to be long and complex. Currently, the volcano is at rest, but there is no doubt that the Isparta town (more than 120 000 people) built on top of the most recent tephra falls is exposed to a major volcanic hazard in the future.En MĂ©diterranĂ©e Orientale, la rĂ©gion active d’Isparta est le siĂšge d’un magmatisme alcalin liĂ© Ă  la distension affectant cette partie de la PĂ©ninsule Anatolienne depuis le MiocĂšne supĂ©rieur. Le volcanisme PliocĂšne est alcalin et trĂšs potassique, depuis des magmas lamprophyriques Ă  lamproĂŻtiques, jusqu’à des tĂ©phriphonolites et des trachytes. La construction du volcan GölcĂŒk au sud d’Isparta marque le dĂ©but d’un nouveau cycle Ă©ruptif aprĂšs une longue pĂ©riode d’arrĂȘt et d’érosion. L’étude morpho-structurale du volcan couplĂ©e aux datations 40K/40Ar sur lave et 39Ar/40Ar sur monograin de feldspath-K indique une histoire Ă©ruptive complexe, nettement plus jeune que l’activitĂ© antĂ©rieure (PliocĂšne). Ces rĂ©sultats prĂ©liminaires montrent que l’activitĂ© volcanique du GölcĂŒk est situĂ©e dans le PlĂ©istocĂšne supĂ©rieur (PalĂ©olithique) entre environ 200 ka et 24 ka. Trois cycles volcaniques majeurs sont reconnus : (1) Cycle I dĂ©butant vers 200 ka avec des Ă©ruptions ignimbritiques majeures avec un ensemble de coulĂ©es pyroclastiques trachytiques comblant les palĂ©o-vallĂ©es ouvertes dans les formations sĂ©dimentaires et les formations volcaniques d’ñge pliocĂšne ; (2) Cycle II avec un Ă©pisode effusif de faible importance succĂšde entre 115 ± 3 ka et 62 ± 2 ka Ă  l’activitĂ© explosive initiale avec la mise en place d’un Ă©difice central constituĂ© de dĂŽmes-coulĂ©es tĂ©phri-phonolitiques ; (3) Cycle III entre 70 ka et 24 ka, l’activitĂ© devient phrĂ©atoplinienne et suit de prĂšs le cycle prĂ©cĂ©dent. Le dynamisme Ă©ruptif phrĂ©atomagmatique est celui d’un maar formĂ© d’un large cratĂšre d’explosion entourĂ© d’un anneau de tufs. La derniĂšre crise volcanique se termine par l’extrusion de plusieurs dĂŽmes de trachyte dans le cratĂšre et de tĂ©phras associĂ©s, de nouvelles coulĂ©es pyroclastiques se mettent vraisemblablement en place vers le nord-ouest. Les donnĂ©es de terrain et les Ăąges 40Ar/39Ar disponibles indiquent que ces derniĂšres manifestations (construction du maar) sont trĂšs rĂ©centes et sub-contemporaines du dernier niveau de retombĂ©es ponceuses sous les immeubles de la ville et des dĂŽmes de lave intra-caldeira. Cet Ăąge rĂ©cent est confirmĂ© par un Ăąge 14C obtenu sur des bois carbonisĂ©s. La morphologie du volcan actuel est relativement bien conservĂ©e, malgrĂ© l’érosion trĂšs active qui remodĂšle dĂ©jĂ  partiellement les pentes. La reprise Ă©ventuelle de l’activitĂ© du volcan constituerait un risque majeur Ă  l’échelle de la rĂ©gion et en particulier pour la ville d’Isparta Ă©tablie au pied de l’édifice, notamment sur les coulĂ©es pyroclastiques et les retombĂ©es ponceuses les plus rĂ©centes

    Aqueductal developmental venous anomaly as an unusual cause of congenital hydrocephalus: a case report and review of the literature

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>Aqueductal stenosis may be caused by a number of etiologies including congenital stenosis, tumor, inflammation, and, very rarely, vascular malformation. However, aqueductal stenosis caused by a developmental venous anomaly presenting as congenital hydrocephalus is even more rare, and, to the best of our knowledge, has not yet been reported in the literature. In this study, we review the literature and report the first case of congenital hydrocephalus associated with aqueductal stenosis from a developmental venous anomaly.</p> <p>Case presentation</p> <p>The patient is a three-day-old, African-American baby girl with a prenatal diagnosis of hydrocephalus. She presented with a full fontanelle, splayed sutures, and macrocephaly. Postnatal magnetic resonance imaging showed triventricular hydrocephalus, suggesting aqueductal stenosis. Examination of the T1-weighted sagittal magnetic resonance imaging enhanced with gadolinium revealed a developmental venous anomaly passing through the orifice of the aqueduct. We treated the patient with a ventriculoperitoneal shunt.</p> <p>Conclusions</p> <p>Ten cases of aqueductal stenosis due to venous lesions have been reported and, although these venous angiomas and developmental venous anomalies are usually considered congenital lesions, all 10 cases became symptomatic as older children and adults. Our case is the first in which aqueductal stenosis caused by a developmental venous anomaly presents as congenital hydrocephalus. We hope adding to the literature will improve understanding of this very uncommon cause of hydrocephalus and, therefore, will aid in treatment.</p

    Transmission of risk preferences from mothers to daughters

    Get PDF
    We study the transmission of risk attitudes in a unique survey of mothers and children in which both participated in an incentivized risk preference elicitation task. We document that risk preferences are correlated between mothers and children when the children are just 7–8 years old. This correlation is only present for daughters. We further show that a measure of maternal involvement is a strong moderator of the association between mothers’ and daughters’ risk tolerance. This is consistent with a role for socialization and parental investment in the intergenerational transmission of risk preferences

    Executive function and theory of mind as predictors of aggressive and prosocial behavior and peer acceptance in early childhood

    Get PDF
    Executive function (EF) and theory of mind (ToM) are related to children’s social interactions, such as aggression and prosocial behavior, as well as their peer acceptance. However, limited research has examined different forms of aggression and the moderating role of gender. This study investigated links between EF, ToM, physical and relational aggression, prosocial behavior and peer acceptance and explored whether these relations are gender specific. Children (N=106) between 46- and 80-months-old completed tasks assessing cool and hot EF and ToM. Teaching staff rated children’s aggression, prosocial behavior, and peer acceptance. EF and ToM predicted physical, but not relational, aggression. Poor inhibition and delay of gratification were uniquely associated with greater physical aggression. EF and ToM did not predict prosocial behavior or peer acceptance. Added to this, gender did not moderate the relation between either EF or ToM and social outcomes. The correlates of aggression may therefore differ across forms of aggression but not between genders in early childhood
    • 

    corecore