Enhancing sampling in atomistic simulations of solid state materials for batteries: a focus on olivine NaFePO4_4

The study of ion transport in electrochemically active materials for energy storage systems requires simulations on quantum-, atomistic- and meso-scales. The methods accessing these scales not only have to be effective but also well compatible to provide a full description of the underlying processes. We propose to adapt the Generalized Shadow Hybrid Monte Carlo (GSHMC) method to atomistic simulation of ion intercalation electrode materials for batteries. The method has never been applied to simulations in solid-state chemistry but it has been successfully used for simulation of biological macromolecules, demonstrating better performance and accuracy than can be achieved with the popular molecular dynamics (MD) method. It has been also extended to simulations on meso-scales, making it even more attractive for simulation of battery materials. We combine GSHMC with the dynamical core–shell model to incorporate polarizability into the simulation and apply the new Modified Adaptive Integration Approach, MAIA, which allows for a larger time step due to its excellent conservation properties. Also, we modify the GSHMC method, without losing its performance and accuracy, to reduce the negative effect of introducing a shell mass within a dynamical shell model. The proposed approach has been tested on olivine NaFePO$_4$, which is a promising cathode material for Na-ion batteries. The calculated Na-ion diffusion and structural properties have been compared with the available experimental data and with the results obtained using MD and the original GSHMC method. Based on these tests, we claim that the new technique is advantageous over MD and the conventional GSHMC and can be recommended for studies of other solid-state electrode and electrolyte materials whenever high accuracy and efficient sampling are critical for obtaining tractable simulation results.MTM2013-46553-C3-1-P Iberdrola Foundation “Grants for Research in Energy and Environment 2014” ELKARTEK Programme KK-2016/00026 BES-2014-068640 BERC 2014-2017 SEV-2013-032

Primeras dataciones microfitopaleontológicas en el sector de Valverde de Burguillo-Jerez de los Caballeros (anticlinorio de Olivenza-Monesterio)

[Resumen] Se exponen los resultados de los estudios microfitopaleontológicos de muestras de la sucesi6n Tentudia (precámbrico del Dominio de Arroyomolinos, "anticlinorio" de Olivenza-Monesterio). La edad asignada para esta sucesión en las transversales de Valverde de BurguillosFregenal y Norte del Valle de Matamoros es de Rifeense, probablemente medio-inferior[Abstract] The results of the microphitopaleontologic studies of samples from Tentudia succession (precambrian from Arroyomolinos Domain, Olivenza-Monesterio "anticlinorium") are exposed. The assignated age to this succesion in the transversals of Valverde-Fregenal and Valle de Matamoros, is Riphean midle-lower, probabl

Reliability of the resonance frequency analysis values in new prototype transepithelial abutments: A prospective clinical study

Resonance frequency analysis (RFA) requires abutment disconnection to monitor implant stability. To overcome this limitation, an experimental transepithelial abutment was designed to allow a SmartPeg to be screwed onto it, in order to determine the prototype abutments repeatability and reproducibility using Osstell ISQ and to assess whether implant length and diameter have an influence on the reliability of these measurements. RFA was conducted with a SmartPeg screwed directly into the implant and onto experimental abutments of different heights of 2, 3.5 and 5 mm. A total of 32 patients (116 implants) were tested. RFA measurements were taken twice for each group from mesial, distal, buccal and palatal/lingual surfaces. Mean values and SD were calculated and Intraclass Correlation Coefficients (ICC) (p < 0.05, IC 95%). The implant stability quotient (ISQ) mean values were 72.581 measured directly to implant and 72.899 (2 mm), 72.391 (3.5 mm) and 71.458 (5 mm) measured from the prototypes. ICC between measurements made directly to implant and through 2-, 3.5-and 5-mm abutments were 0.908, 0.919 and 0.939, respectively. RFA values registered through the experimental transepithelial abutments achieved a high reliability. Neither the implant length nor the diameter had any influence on the measurements’ reliability

Coherent pion production in neutrino nucleus collision in the 1 GeV region

We calculate cross sections for coherent pion production in nuclei induced by neutrinos and antineutrinos of the electron and muon type. The analogies and differences between this process and the related ones of coherent pion production induced by photons, or the (p,n) and $(^3 He, t)$ reactions are discussed. The process is one of the several ones occurring for intermediate energy neutrinos, to be considered when detecting atmospheric neutrinos. For this purpose the results shown here can be easily extrapolated to other energies and other nuclei.Comment: 13 pages, LaTex, 8 post-script figures available at [email protected]

Breeding, planktonic and settlement factors shape recruitment patterns of one of the last remaining major population of Pinna nobilis within Spanish waters

The pen shell, Pinna nobilis L., is a critically endangered bivalve threatened by mass mortality events throughout the Mediterranean, but the Alfacs Bay (Ebro Delta) still hosts many healthy individuals. Herein, we study the main factors controlling recruitment patterns in this locality, including gonadal development and abundance of critical life-stages, as well as the effect of environmental factors. Growth records from empty shells suggested a single major peak of recruitment during a period of 11 years, although many juveniles were found in two very shallow sand bars possibly acting as a barrier for water circulation and as a trap for larvae. Collectors deployed outside these sand bar areas showed zero settlers, and the availability of planktonic larvae was very low. Gonadal examination evidenced breeding throughout the summer period with successive hermaphroditism, but 20% of individuals were simultaneous hermaphrodites, a condition that has been associated with environmental stress and that could lead to in-breeding depression and potentially reduced fertility. Yet, given the large size of the population and the wide breeding period observed, planktonic processes causing larval mortality such as freshwater discharges from rice locally important rice agriculture are also proposed as possible impacts accounting for patterns of low larval availability.info:eu-repo/semantics/acceptedVersio

A Production Calendar Based on Water Temperature, Spat Size, and Husbandry Practices Reduce OsHV-1 μvar Impact on Cultured Pacific Oyster Crassostrea gigas in the Ebro Delta (Catalonia), Mediterranean Coast of Spain

Since 2006, the production of Pacific oyster Crassostrea gigas in the Ebro Delta area has dramatically declined from around 800 metric tons (MT) per year to 138 MT in 2011. This decline in production has had a significant socio-economic impact in a region where the shellfish sector is a traditional economic activity for many families. The identified agent responsible for this reduction in C. gigas production was Ostreid Herpesvirus microvar (OsHV-1 μvar), which has been associated with C. gigas spat mortalities in France, and in many other countries. In Spain the episodes of mortality became critical for the regional shellfish production between 2008 until 2014, with mortality percentage up to 100%. In this study, local hatchery C. gigas spat was used as sentinel animals for epidemiological studies and management tests carried out with the aim of reducing oyster mortality in the Ebro Delta area. A production calendar mainly based on water temperature dynamics was designed around an optimal schedule for spat immersion. The mmersion calendar included two optimal periods for spat immersion, in summer when temperatures are ≥25◦C and at the end of autumn and beginning of winter when they are ≤13◦C. Such production planning has reduced mortalities from 80% (in 2014 and previous years) to 2–7.5% in 2015 in cemented oysters. Furthermore, other recommendations related to spat immersion size, culture density and methodology, and cementing calendar, which helped to achieve the results presented, were also recorded and transferred to local producers. This work presents a successfully tested management strategy reducing OsHV-1 μvar impact by designing new field management practices mainly focused on the handling and timing of spat immersion. This approach could be used as a management model in areas presenting similar production practices and environmental characteristics.info:eu-repo/semantics/publishedVersio

Projectile Δ\Delta and target-Roper excitation in the p (d, d')X reaction

In this paper we compare a model that contains the mechanisms of $\Delta$ excitation in the projectile and Roper excitation in the target with experimental data from two (d, d') experiments on a proton target. The agreement of the theory with the experiment is fair for the data taken at T_d = 2.3 GeV. The $\Delta$ excitation in the projectile is predicted close to the observed energy with the correct width. The theory, however, underpredicts by about 40% the cross sections measured at T_d = 1.6 GeV at angles where the cross section has fallen by about two orders of magnitude. The analysis done here allows to extract an approximate strength for the excitation of the Roper [N^*(1440)] excitation and a qualitative agreement with the theoretical predictions is also found.Comment: 8 ps figure

Delta excitation in K^+-nucleus collisions

We present calculations for \Delta excitation in the (K^+,K^+) reaction in nuclei. The background from quasielastic K^+ scattering in the \Delta region is also evaluated and shown to be quite small in some kinematical regions, so as to allow for a clean identification of the \Delta excitation strength. Nuclear effects tied to the \Delta renormalization in the nucleus are considered and the reaction is shown to provide new elements to enrich our knowledge of the \Delta properties in a nuclear medium.Comment: 11 pages, 6 figures, LaTe