Heterogeneous nucleation and heat flux avalanches in La(Fe, Si)13 magnetocaloric compounds near the critical point

The phase transformation kinetics of LaFe11.41Mn0.30Si1.29-H1.65 magnetocaloric compound is addressed by low rate calorimetry experiments. Scans at 1 mK/s show that its first order phase transitions are made by multiple heat flux avalanches. Getting very close to the critical point, when the transition becomes of the second order type, the step-like discontinuous behaviour associated with avalanches is smoothed out and the thermal hysteresis disappears. This result is confirmed by magneto-resistivity measurements and allows to obtain accurate values of the temperature hysteresis (DThyst = 0.37 K) at zero external magnetic field and of the critical field (Hc = 1.19 T). The number and magnitude of heat flux avalanches change as the magnetic field strength is increased, showing the interplay between the intrinsic energy barrier between phases and the microstructural disorder of the sample

APPLICATION OF PHOTOGRAMMETRY TO BRAIN ANATOMY

This paper presents an on-going interdisciplinary collaboration to advance brain connectivity studies. Despite the evolution of noninvasive methods to investigate the brain connectivity structure using the diffusion magnetic resonance, in the neuroscientific community there is an open debate how to collect quantitative information of the main neuroanatomical tracts. Information on the structure and main pathways of brain's white matter are generally derived by manual dissection of the brain ex-vivo. This paper wants to present a photogrammetric method developed to support the collection of metric information of the main pathways, or set of fibres, of the white matter of brain. For this purpose, multi-temporal photogrammetric acquisitions, with a resolution better than 100 microns, are performed at different stages of the brain's dissection, and the derived dense point clouds are used to annotate the stem, i.e., the region where there is a greater density of fibres of a given pathway, and termination points of several neuroanatomical tracts, i.e. fibres

Algebraic damping in the one-dimensional Vlasov equation

We investigate the asymptotic behavior of a perturbation around a spatially non homogeneous stable stationary state of a one-dimensional Vlasov equation. Under general hypotheses, after transient exponential Landau damping, a perturbation evolving according to the linearized Vlasov equation decays algebraically with the exponent -2 and a well defined frequency. The theoretical results are successfully tested against numerical $N$-body simulations, corresponding to the full Vlasov dynamics in the large $N$ limit, in the case of the Hamiltonian mean-field model. For this purpose, we use a weighted particles code, which allows us to reduce finite size fluctuations and to observe the asymptotic decay in the $N$-body simulations.Comment: 26 pages, 8 figures; text slightly modified, references added, typos correcte

A priori control of zeolite phase competition and intergrowth with high-throughput simulations

Zeolites are versatile catalysts and molecular sieves with large topological diversity, but managing phase competition in zeolite synthesis is an empirical, labor-intensive task. In this work, we controlled phase selectivity in templated zeolite synthesis from first principles by combining high-throughput atomistic simulations, literature mining, human-computer interaction, synthesis, and characterization. Proposed binding metrics distilled from more than 586,000 zeolite-molecule simulations reproduced the extracted literature and rationalized framework competition in the design of organic structure-directing agents. Energetic, geometric, and electrostatic descriptors of template molecules were found to regulate synthetic accessibility windows and aluminum distributions in pure-phase zeolites. Furthermore, these parameters allowed us to realize an intergrowth zeolite through a single bi-selective template. The computation-first approach enables control of both zeolite synthesis and structure composition using a priori theoretical descriptors.D.S.-K. and R.G.-B. acknowledge the Energy Initiative (MITEI) and MIT International Science and Technology Initiatives (MISTI) Seed Funds. D.S.-K. was also funded by the MIT Energy Fellowship. C.P., E.B.-J., M.M., and A.C. acknowledge financial support by the Spanish government through the “Severo Ochoa” program (SEV-2016-0683, MINECO) and grant RTI2018-101033-B-I00 (MCIU/AEI/FEDER, UE). E.B.-J. acknowledges the Spanish government for an FPI scholarship (PRE2019-088360). Z.J., E.O., S.K., and Y.R.-L. acknowledge partial funding from Designing Materials to Revolutionize and Engineer our Future (DMREF) from the National Science Foundation (NSF); awards 1922311, 1922372, and 1922090; and the Office of Naval Research (ONR) under contract N00014-20-1-2280. S.K. was additionally funded by the Kwanjeong Educational Fellowship. Z.J. was also supported by the Department of Defense (DoD) through the National Defense Science Engineering Graduate (NDSEG) fellowship program. T.W. acknowledges financial support by the Swedish Research Council (grant no. 2019-05465). Computer calculations were executed at the Massachusetts Green High-Performance Computing Center with support from MIT Research Computing and at the Extreme Science and Engineering Discovery Environment (XSEDE) (53) Expanse through allocation TG-DMR200068

Towards a Proof Theory of G\"odel Modal Logics

Analytic proof calculi are introduced for box and diamond fragments of basic modal fuzzy logics that combine the Kripke semantics of modal logic K with the many-valued semantics of G\"odel logic. The calculi are used to establish completeness and complexity results for these fragments