The quasi two-day wave: the results of numerical simulation with the COMMA - LIM Model

The quasi two-day wave (QTDW), a prominent feature of the mesosphere mainly around solstices, is simulated with the COMMA-LIM Model (Cologne Model of the Middle Atmosphere - Leipzig Institute for Meteorology). The calculations are made approximately one month after the summer solstice in the Northern Hemisphere when the QTDW reaches its maximum in the mesosphere and lower thermosphere. The results show that the QTDW produces a moderate westward forcing of the zonally averaged flow and a poleward driving of the residual mean meridional circulation.Die Quasi Zwei-Tage Welle (QTDW), eine deutliche Erscheinung in der Mesosphäre kurz nach dem Sommer Solstitium, wird mit dem COMMA-LIM Modell (Cologne Model of the Middle Atmosphere - Leipzig Institute for Meteorology) simuliert. Die Zwei-Tage Welle wurde unter Juli-Bedingungen an der unteren Modellgrenze angeregt, zu der Zeit, zu der sie ihr Maximum in der Mesosphäre und unteren Thermosphäre erreicht. Die Ergebnisse zeigen eine sich westwärts ausbreitende Welle, die auf den Grundstrom eine moderate Beschleunigung nach Westen ausübt. Die residuelle mittlere Meridional Zirkulation erfährt dadurch eine zum Pol gerichtete Triebkraft

Zeitgleiche Applikation der Impfstoffe ECOPORC SHIGA® und Stellamune® One bei Ferkeln in der ersten Lebenswoche

Das Ziel der vorliegenden Untersuchung war die Überprüfung der Wirksamkeit einer One-Shot Impfung gegen M. hyopneumoniae (Stellamune® One, Elanco Animal Health, Lilly Deutschland GmbH, Bad Homburg, Deutschland) bei zeitgleicher Applikation einer Vakzine gegen die Ödemkrankheit (ECOPORC SHIGA®, IDT Biologika, Dessau-Rosslau, Deutschland) bei Ferkeln in der ersten Lebenswoche im Rahmen einer Feldstudie. Hierfür wurde ein geschlossener, EDEC-negativer Betrieb in Süddeutschland gewählt, dem nach einem Präscreening ein Infektionsstatus mit M. hyopneumoniae anhand IHC und EP-ähnlichen Lungenveränderungen am Schlachthof nachgewiesen werden konnte. Unter Berücksichtigung aller untersuchter Parameter wurde schlussendlich in dieser Studie gezeigt, dass die kombinierte Verabreichung eines Impfstoffes gegen das Stx2e-Toxin und M. hyopneumoniae verglichen mit der einzelnen Applikation des M. hyopneumoniae-Impfstoffes als sicher und verträglich zu bewerten ist. Durch die zeitgleiche Verabreichung von Stellamune® One und ECOPORC SHIGA® konnten im Vergleich zur monovalenten M. hyopneumoniae-Vakzine keine signifikanten Unterschiede bezüglich der Effektivität der Vakzinen sowie der Ausbildung einer humoralen Immunantwort gesehen werden

Zeitgleiche Applikation der Impfstoffe ECOPORC SHIGA® und Stellamune® One bei Ferkeln in der ersten Lebenswoche

Das Ziel der vorliegenden Untersuchung war die Überprüfung der Wirksamkeit einer One-Shot Impfung gegen M. hyopneumoniae (Stellamune® One, Elanco Animal Health, Lilly Deutschland GmbH, Bad Homburg, Deutschland) bei zeitgleicher Applikation einer Vakzine gegen die Ödemkrankheit (ECOPORC SHIGA®, IDT Biologika, Dessau-Rosslau, Deutschland) bei Ferkeln in der ersten Lebenswoche im Rahmen einer Feldstudie. Hierfür wurde ein geschlossener, EDEC-negativer Betrieb in Süddeutschland gewählt, dem nach einem Präscreening ein Infektionsstatus mit M. hyopneumoniae anhand IHC und EP-ähnlichen Lungenveränderungen am Schlachthof nachgewiesen werden konnte. Unter Berücksichtigung aller untersuchter Parameter wurde schlussendlich in dieser Studie gezeigt, dass die kombinierte Verabreichung eines Impfstoffes gegen das Stx2e-Toxin und M. hyopneumoniae verglichen mit der einzelnen Applikation des M. hyopneumoniae-Impfstoffes als sicher und verträglich zu bewerten ist. Durch die zeitgleiche Verabreichung von Stellamune® One und ECOPORC SHIGA® konnten im Vergleich zur monovalenten M. hyopneumoniae-Vakzine keine signifikanten Unterschiede bezüglich der Effektivität der Vakzinen sowie der Ausbildung einer humoralen Immunantwort gesehen werden

Electro-Chemical Modelling of Laser Structured Electrodes

A simulation study performed in the scope of the project RealLi! is presented. One of the project’s main goals is to improve NMC811 and graphite electrode cycling capacities at high C-rates. The rapid charging and discharging capability of batteries is improved using laser ablation to introduce structures into the surface of the electrode composite layers. Due to improved transport kinetics, this not only improves the electrochemical properties in the high-current range, but also homogenizes and accelerates the electrolyte wetting during production as a side effect. This is particularly advantageous in thick-film electrodes for providing high energy densities. This study supports the laser structuring process of battery electrodes [1][2] via a virtual optimisation, based on electro-chemical battery models. The electrodes are structured by ultrafast laser ablation, with parallel channels being introduced along the electrode surface. This modification enables an easier electrolyte penetration, a reduced charge transfer resistance, and shortened lithium-ion transport pathways which finally leads to a reduced diffusion overpotential at high C-rates. The geometrical parameters of this process (pitch distance, width, and cross-sectional shape of laser-generated micro-channels) and their impact on cell performance are virtually optimised by simulations. The simulations are based on a homogenised multi-scale model, applied in 2D/3D macroscopic cuts, coupled with 1D microscopic particle cuts. The 2D/3D macroscopic electrolyte transport equations are common concentrated electrolyte equations. The microscopic particle transport equations are either a set of non-linear Fick’s Diffusion equations [3] that are used to describe spherical symmetric NMC811 materials or a set of Cahn-Hilliard equations [4] that consistently describe the phase separating nature of graphite anodes in cylindrically symmetric particles. The underlying numerical method is an implicit-multi-scale finite-element-method [3] that allows for a flexible implementation of such models. The first results of this ongoing project will be presented along with the overall structure of the method and its implementation. The results include geometrical as well as electro-chemical parameter variations and their respective sensitivity analysis. Furthermore, in the discussed electrode geometry the possible anisotropic structure of an electrode (due to particle shape and distribution) has a bigger impact than in unstructured electrodes. The improved transport pathways along the channels, therefore, imply the necessity of a more thorough homogenisation than it is usually done, for example in a Newman-Model approach. A long-term goal of this work is to enable a significant increase in areal energy density, i.e., the use of thicker electrode films and the use of advanced high energy materials in battery electrodes. [1]3D silicon/graphite composite electrodes for high-energy lithium-ion batteries, W. Pfleging et.al., Electrochimica Acta, Volume 317, 2019, Pages 502-508, J Power Sources 145 (5), 2345-2356 [2]Recent progress in laser texturing of battery materials: a review of tuning electrochemical performances, related material development, and prospects for large-scale manufacturing,W. Pfleging,International Journal of Extreme Manufacturing, Vol 3, 2020 [3]Derivation of a multi-scale battery model and its high-performance computing implementation, F. Pichler, Doctoral Thesis, Graz, 2018 [4]Phase Transformation Dynamics in Porous Battery Electrodes, R. Ferguson, M. Z. Bazant, Electrochimica Acta, Volume 146, Pages 89-97, 2014 Figure

The 48 Layer COMMA-LIM Model: model description, new aspects, and climatology

COMMA-LIM (Cologne Model of the Middle Atmosphere - Leipzig Institute for Meteorology) ist ein 3D-mechanistisches Gitterpuktsmodell, welches sich von ca. 0 bis 135 km in logarhitmischen Druckkordinaten z = -H ln(p=p0) erstreckt, wobei H=7 km und p0 den Referenzdruck am unteren Rand bezeichnet. Die vertikale Auflösung von COMMA-LIM wurde auf 48 Schichten erhöht. Zugleich wurde die Beschreibung des Strahlungsprozesses verbessert, zusammen mit den Beiträgen zur Temperaturbilanz durch atmosphärische Wellen und Turbulenz. Weitere Veränderungen betreffen die numerische Realisation der horizontalen Diffusion und des Filterproblems. Die Beschreibung ist unterteilt in den dynamischen Teil und die Strahlungsbeträge. Die jahreszeitlichen Klimatologien werden vorgestellt und diskutiert.COMMA-LIM (Cologne Model of the Middle Atmosphere - Leipzig Institute for Meteorology) is a 3D-mechanistic gridpoint model extending up from 0 to 135 km with a logharithmic vertical coordinate z = -H ln(p=p0), where H=7 km and p0 is the reference pressure at lower boundary. The resolution of the 24 layer version has been increased to 48 layers and several improvements are made in the parameterisation of radiative processes, heating/cooling due to atmospheric waves and turbulence, as well as in the numerical realization of the horizontal diffusion and filtering. This description is divided into the section describing the changes in the dynamical part and the modifications in radiation routines. After all, the seasonal climatologies will be shown and discussed to demonstrate what the COMMA-LIM is capable of reproducing

Quantum spin systems at positive temperature

We develop a novel approach to phase transitions in quantum spin models based on a relation to their classical counterparts. Explicitly, we show that whenever chessboard estimates can be used to prove a phase transition in the classical model, the corresponding quantum model will have a similar phase transition, provided the inverse temperature $\beta$ and the magnitude of the quantum spins \CalS satisfy \beta\ll\sqrt\CalS. From the quantum system we require that it is reflection positive and that it has a meaningful classical limit; the core technical estimate may be described as an extension of the Berezin-Lieb inequalities down to the level of matrix elements. The general theory is applied to prove phase transitions in various quantum spin systems with \CalS\gg1. The most notable examples are the quantum orbital-compass model on $\Z^2$ and the quantum 120-degree model on $\Z^3$ which are shown to exhibit symmetry breaking at low-temperatures despite the infinite degeneracy of their (classical) ground state.Comment: 47 pages, version to appear in CMP (style files included

Layering in the Ising model

We consider the three-dimensional Ising model in a half-space with a boundary field (no bulk field). We compute the low-temperature expansion of layering transition lines

Provable first-order transitions for liquid crystal and lattice gauge models with continuous symmetries

We consider various sufficiently nonlinear sigma models for nematic liquid crystal ordering of RP^{N-1} type and of lattice gauge type with continous symmetries. We rigorously show that they exhibit a first-order transition in the temperature. The result holds in dimension 2 or more for the RP^{N-1} models and in dimension 3 or more for the lattice gauge models. In the two-dimensional case our results clarify and solve a recent controversy about the possibility of such transitions. For lattice gauge models our methods provide the first proof of a first-order transition in a model with a continuous gauge symmetry

Anderson localization for a class of models with a sign-indefinite single-site potential via fractional moment method

A technically convenient signature of Anderson localization is exponential decay of the fractional moments of the Green function within appropriate energy ranges. We consider a random Hamiltonian on a lattice whose randomness is generated by the sign-indefinite single-site potential, which is however sign-definite at the boundary of its support. For this class of Anderson operators we establish a finite-volume criterion which implies that above mentioned the fractional moment decay property holds. This constructive criterion is satisfied at typical perturbative regimes, e. g. at spectral boundaries which satisfy 'Lifshitz tail estimates' on the density of states and for sufficiently strong disorder. We also show how the fractional moment method facilitates the proof of exponential (spectral) localization for such random potentials.Comment: 29 pages, 1 figure, to appear in AH