The mathematical P2D model is a system of strongly coupled nonlinear parabolic-elliptic equations that describes the electrodynamics of lithium-ion batteries. In this paper, we present the numerical ...analysis of a finite element-implicit Euler scheme for such a model. We obtain error estimates for both the spatially semidiscrete and the fully discrete systems of equations, and establish the existence and uniqueness of the fully discrete solution.
Microplastic deposition in marine sediments is a geographically widespread problem. This study examines microplastics in intertidal and subtidal sediments at 87 locations in habitats designated as ...Special Areas of Conservation (SACs) and Special Protection Areas (SPAs) on the coastline of Ireland. Established methodological approaches including, organic matter digestion, density separation, particle extraction and polymer identification were applied. Microplastic abundance was closely related with distance from known sources and concentrations were greater in intertidal as opposed to subtidal sediments. Colourless, polyethylene fibres and polypropylene fragments were the most abundant MP recorded and finer grained sediments were shown to entrap more MPs than coarser sediments. The results demonstrate that an understanding of potential sources of pollution, sediment type and hydrodynamic conditions are very important in terms of MP abundance and distribution in marine sediments and also in terms of effective waste management strategies and policy aimed at reducing the global plastics problem.
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•Microplastic concentrations greater in intertidal versus subtidal sediments•Finer grain sediments entrap more microplastics than coarser grained sediments.•Colourless, polyethylene fibres and polypropylene fragments were the most abundant.•Distance from source and sediment type are key factors for distribution of MPs.
The accelerated discard and mismanagement of human-made products are resulting in the continued input of litter into the oceans. Models and field observations show how floating litter can accumulate ...in remote areas throughout the global ocean, but far less is known about the non-floating litter fraction. Seagrass meadows play an important role in the sediment and natural-debris dynamics, and likely also in the storage and processing of non-floating litter. In this work, non-floating litter was studied across six Posidonia oceanica meadows. Litter accumulated mainly around the landside edge of the meadow. The outer margin of the edge predominantly trapped macro-litter, whilst microplastics accumulated mainly along the inner margin. On average, macro-litter concentrations increased 3-fold after heavy rainfall. Retention of non-floating litter by coastal meadows facilitates the recurrent landward-seaward conveyance of the easily-transportable litter (mainly plastic items) and its fragmentation before it is buried or transferred to deeper areas.
•Posidonia oceanica meadows trap land-sourced litter, from micro to macro.•A 10-meter strip at the edge of the meadow is the main area of litter accumulation.•Heavy rain events lead to significantly higher litter volumes in the seagrass meadows.•Highmobile items prevailed on the outer edge of the meadow, while low-mobile items spread further into the meadow.
•The coupled criterion is used to analyze the effect of a flaw on the strength.•Both sharp and blunt geometries of the defect are considered.•A defect with a size smaller than the characteristic ...material length has no effect.•Introducing flaws with controlled sizes enables to identify the fracture parameters.•The approach allows to recover the Orowan-like regime of the Orowan-Petch plot.
The effect of small critical flaws on the strength of polycrystalline ceramic materials is analyzed with the help of an initiation criterion combining both a stress and an energy conditions. If the size of the defect is smaller than the characteristic material length, numerical predictions reveal that the defect (either sharp or blunt) has no effect on the strength. This result is in a good agreement with experimental results obtained from the strength measurements of ceramic materials with controlled flaws. Combining two fracture tests after introducing flaws with controlled sizes enables to identify the fracture parameters of the ceramic material.
We present a stabilized Backward Difference Formula of order 2-Lagrange Galerkin method to integrate the incompressible Navier–Stokes equations at high Reynolds numbers (Re). The stabilization of the ...conventional Lagrange–Galerkin method is done via a local projection technique for inf–sup stable finite elements. We prove that for a finite time T the a priori error estimate for velocity in a mesh dependent norm is O(hm+Δt2), whereas the error for pressure in the l2(L2(D)) norm is O(hm+Δt2), with error constants that are independent of the Re−1; here, m denotes the degree of the polynomials of the velocity finite element space. The size of the stabilization parameters is calculated from the velocity error estimate in a way that the error is optimal when the solution is sufficiently smooth. Numerical examples at high Reynolds numbers show the robustness of our method.
Abstract
Eridanus II (Eri II) is an ultrafaint dwarf (UFD) galaxy (
M
V
= −7.1) located at a distance close to the Milky Way virial radius. Early shallow color–magnitude diagrams (CMDs) indicated ...that it possibly hosted an intermediate-age or even young stellar population, which is unusual for a galaxy of this mass. In this paper, we present new Hubble Space Telescope/Advanced Camera for Surveys CMDs reaching the oldest main-sequence turnoff with excellent photometric precision and derive a precise star formation history (SFH) for this galaxy through CMD fitting. This SFH shows that the bulk of the stellar mass in Eri II formed in an extremely short star formation burst at the earliest possible time. The derived star formation rate profile has a width at half maximum of 500 Myr and reaches a value compatible with null star formation 13 Gyr ago. However, tests with mock stellar populations and with the CMD of the globular cluster M92 indicate that the star formation period could be shorter than 100 Myr. From the quantitative determination of the amount of mass turned into stars in this early star formation burst ( ∼2 × 10
5
M
⊙
) we infer the number of supernova (SN) events and the corresponding energy injected into the interstellar medium. For reasonable estimates of the Eri II virial mass and values of the coupling efficiency of the SN energy, we conclude that Eri II could be quenched by SN feedback alone, thus casting doubts on the need to invoke cosmic reionization as the preferred explanation for the early quenching of old UFD galaxies.
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•Hardness anisotropy associated with crystal orientation governs surface damage morphology in LiNbO3.•A 20% difference in hardness can double the characteristic strength of ...LiNbO3.•Tailored high Young’s modulus surface planes of LiNbO3 can significantly increase its characteristic strength.
Piezoelectric single crystalline materials are paramount for high-speed data transfer in 5G technologies. The functionality of the end-devices demands temperature independent frequency filtering and high surface acoustic wave velocities, which are associated with the orientation dependent thermo-physical properties of the piezoelectric substrate material. Single crystalline Lithium Niobate (LiNbO3), cut in particular directions, has proven to have outstanding functional properties, yet its brittle character along with the highly anisotropic mechanical properties may limit its use in demanding applications.
In this study, the effect of crystal orientation on hardness and on mechanical strength is demonstrated by comparing nanoindentation results and finite element analysis supported biaxial strength experiments for two LiNbO3 samples with different orientation. It is demonstrated that the crystal anisotropy leads to differences in hardness up to ∼ 20% between both orientations, with the characteristic strength being double in the harder direction. The observed correlation is rationalized based on the effect of surface finish and distinct sub-surface damage in the corresponding crystal orientations. Additional strength measurements on nano-scratched samples revealed a significantly higher remaining strength for the harder orientation due to less (sub-) surface damage. These findings can be exploited in future design of single crystalline substrate materials with higher reliability.
The factors that cause a preterm birth (PTB) are not completely understood up to date. Moreover, PTB is more common in pregnancies achieved by in-vitro fertilization (IVF) than in spontaneous ...pregnancies. Our aim was to compare the composition of vaginal microbiome at 12 weeks of gestation between women who conceived naturally or through IVF in order to study whether IVF PTB-risk could be related to vaginal microbiome composition. We performed an observational, prospective and multicentre study among two public hospitals and a fertility private clinic in Spain. Vaginal swabs from 64 pregnant women at 12 weeks of gestation were collected to analyse the microbiome composition by sequencing the V3-V4 region of the 16S rRNA. Our results showed that the vaginal microbiome signature at 12 weeks of pregnancy was different from women who conceived naturally or through IVF. The beta diversity and the genus composition were different between both cohorts. Gardnerella, Neisseria, Prevotella, and Staphylococcus genus were enriched genus in the vaginal microbiome from the IVF group, allowing us to create a balance model to predict both cohorts. Moreover, at species level the L. iners abundance was higher and L. gasseri was lower in the IVF group. As a conclusion, our findings were consistent with a proposed framework in which IVF pregnancy are related to risk for preterm birth (PTB) suggesting vaginal microbiome could be the reason to the relation between IVF pregnancy and risk for PTB.
Canopy-forming seaweeds sustain critical ecosystem services in coastal habitats. Around the world, many of these seaweeds are suffering strong declines, mainly attributed to the progressive increase ...in sea surface temperature, in combination with other stressors due to current global changes. The southernmost part of the NE Atlantic is among those areas most affected by climate change. In this study, we estimated the distributional contractions of seven of the most conspicuous seaweeds from the Atlantic coasts of the Iberian Peninsula using an “Extent of Occurrence” methodology. Overall, during the last three decades, range shifts have been more pronounced east of the Cantabrian Sea than along the western coast of the Iberian Peninsula. In particular, regions with a semi-permanent summer upwelling seem to be critical to the persistence of brown seaweeds, fucoids and kelps. Range contractions of the cold-temperate fucoids were estimated to be ca. 21% and 45% for
Himanthalia elongata
and
Fucus serratus
, respectively; and for the kelps
Saccharina latissima
and
Laminaria hyperborea,
6% and 14%, respectively. Range contractions for warm-temperate kelps were estimated to be ca. 13% and 10% for
Saccorhiza polyschides
and
L. ochroleuca
, respectively. Finally, a decline in the warm-temperate red algae
Gelidium corneum
occurred only in the easternmost area of the Cantabrian Sea (Basque Country), leading to a distributional contraction of 7%. We recommend conservation actions to better manage the remnant populations of these canopy-forming seaweeds, and their inclusion in national and regional catalogues of endangered species and on international Red Lists.
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