Numerical approximation of statistical solutions of scalar conservation laws

We propose efficient numerical algorithms for approximating statistical solutions of scalar conservation laws. The proposed algorithms combine finite volume spatio-temporal approximations with Monte Carlo and multi-level Monte Carlo discretizations of the probability space. Both sets of methods are proved to converge to the entropy statistical solution. We also prove that there is a considerable gain in efficiency resulting from the multi-level Monte Carlo method over the standard Monte Carlo method. Numerical experiments illustrating the ability of both methods to accurately compute multi-point statistical quantities of interest are also presented

Rotational ‘cooling’ and ‘heating’ of OH+(3Σ−) by collisions with He: quantum dynamics revealing propensity rules under ion trap conditions

[EN]Multichannel scattering calculations are presented for the low-energy collisions of the OH+ cation and He atoms, using an ab initio evaluation of the interaction potential, which had been obtained in earlier work, and a time-independent, multichannel treatment of the quantum dynamics carried out in this study using our in-house scattering code ASPIN. Given the presence of spin-rotation coupling effects, within an essentially electrostatic formulation of the interaction forces with He atoms in the trap, the ensuing propensity rules which control the relative size of the state-changing cross sections and of the corresponding inelastic rates, also computed at the most likely temperatures in an ion trap, are presented and analysed in detail

Collisional cooling of internal rotation inMgH+ions trapped with He atoms: Quantum modeling meets experiments in Coulomb crystals

[EN]Using the ab initio computed potential energy surface for the electronic interaction of the MgH+(1) ion with the He(1S) atom, we calculate the relevant state-changing rotationally inelastic collision cross sections from a quantum treatment of the multichannel scattering problem. We focus on the quantum dynamics at the translationally low energies for the present partners discussed in earlier, cold ion trap experiments (see below), which we wish to model in detail. The corresponding state-changing rates computed between the lower rotational states of the molecular ion are employed to describe the time-evolution kinetics followed by recent experiments on Coulomb-crystallized MgH+(1), where the ions are rotationally cooled by micromotion tuning after being uploaded into the trap of He as a buffer gas. The present computational modeling of the final ion rotational temperatures in the experiments turns out to agree very well with the observations and points at a fast equilibration between rotational and thermal temperatures of the ions

Modeling Quantum Kinetics in Ion Traps: State-changing Collisions for OH+(3Σ- ) Ions with He as a Buffer Gas

[EN]We present quantum scattering calculations for rotational state-changing cross sections and rates, up to about 50 K of ion translational temperatures, for the OH+ molecular ion in collision with He atoms as the buffer gas in the trap. The results are obtained both by using the correct spin-rotation coupling of angular momenta and also within a recoupling scheme that treats the molecular target as a pseudo-(1Σ+) state, and then compares our findings with similar data for the OH−(1Σ+) molecular partner under the same conditions. This comparison intends to link the cation behaviour to the one found earlier for the molecular anion. The full calculations including the spin-rotation angular momenta coupling effects have been recently reported (L. González-Sánchez and R. Wester and F.A. Gianturco, Mol.Phys.2018, DOI 10.1080/00268976.2018.1442597) with the aim of extracting specific propensity rules controlling the size of the cross sections. The present study is instead directed to modelling trap cooling dynamics by further obtaining the solutions of the corresponding kinetics equations under different trap schemes so that, using the presently computed rates can allow us to indicate specific optimal conditions for the experimental setup of the collisional rotational cooling in an ion trap for the system under study

Modeling and dynamics of a two-line kite

A mathematical model of a kite connected to the ground by two straight tethers of varying lengths is presented and used to study the traction force generated by kites flying in cross-wind conditions. The equations of motion are obtained by using a Lagrangian formulation, which yields a low-order system of ordinary differential equations free of constraint forces. Two parameters are chosen for the analysis. The first parameter is the wind velocity. The second parameter is one of the stability derivatives of the aerodynamic model: the roll response to the sideslip angle, known also as effective dihedral. This parameter affects significantly the lateral dynamics of the kite. It has been found that when the effective dihedral is below a certain threshold, the kite follows stable periodic trajectories, and naturally flies in cross-wind conditions while generating a high tension along both tethers. This result indicates that kite-based propulsion systems could operate without controlling tether lengths if kite design, including the dihedral and sweep angles, is done appropriately. If both tether lengths are varied out-of-phase and periodically, then kite dynamics can be very complex. The trajectories are chaotic and intermittent for values of the effective dihedral below a certain negative threshold. It is found that tether tensions can be very similar with and without tether length modulation if the parameters of the model are well-chosen. The use of the model for pure traction applications of kites is discussedThis work was supported by the Ministerio de Economía y Competitividad of Spain and the European Regional Development Fund under the project ENE2015-69937-R (MINECO/FEDER, UE). GSA work is supported by the Ministerio de Economía y Competitividad of Spain under the Grant RYC-2014-15357. MGV was partially supported by grant TRA2013-41103-P (MINECO/FEDER, UE). RS was partially supported by the projects AWESCO (H2020-ITN-642682) and REACH (H2020-FTIPilot-691173)

Sistemas de estabilización de talud y análisis de costos del km 90+000 al 100+000 de la carretera Huancayo Huancavelica, 2018

El desarrollo del proyecto de investigación tiene por objetivo realizar un estudio de la estabilidad de taludes y proponer un sistema de estabilización ideal en el Km 90+000 al 100+000 de la carretera Huancayo, Huancavelica. Para conseguir una idónea evaluación de la problemática de la zona de estudio se ha hecho la recopilación de la información de suelo que permita diseñar el sistema de estabilización idónea. Para lograr el objetivo se ha hecho el uso de hojas de cálculos. Una vez concluido el análisis de la problemática de la zona, se realizará un análisis de la posible alternativa de solución, en este caso particular será mediante un muro de gaviones, y muro de concreto ciclópeo toda vez que en la zona se tiene cerca el rio Palca que servirá para abastecer con piedras de canto que hace de esta solución la más factible

Functional insights into the testis transcriptome of the edible sea urchin Loxechinus albus

© The Author(s) 2016. The edible sea urchin Loxechinus albus (Molina, 1782) is a keystone species in the littoral benthic systems of the Pacific coast of South America. The international demand for high-quality gonads of this echinoderm has led to an extensive exploitation and decline of its natural populations. Consequently, a more thorough understanding of L. albus gonad development and gametogenesis could provide valuable resources for aquaculture applications, management, conservation and studies about the evolution of functional and structural pathways that underlie the reproductive toolkit of marine invertebrates. Using a high-throughput sequencing technology, we explored the male gonad transcriptome of this highly fecund sea urchin. Through a de novo assembly approach we obtained 42,530 transcripts of which 15,544 (36.6%) had significant alignments to known proteins in public databases. From these transcripts, approximately 73% were functionally annotated allowing the identification of several candidate genes that are likely to play a central role in developmental processes, nutrient reservoir activity, s exual reproduction, gamete generation, meiosis, sex differentiation, sperm motility, male courtship behavior and fertilization. Additionally, comparisons with the male gonad transcriptomes of other echinoderms revealed several conserved orthologous genes, suggesting that similar functional and structural pathways underlie the reproductive development in this group and other marine invertebrates.Link_to_subscribed_fulltex

Computing rotational energy transfers of OD−/OH− in collisions with Rb: isotopic effects and inelastic rates at cold ion-trap conditions

[EN]We report close-coupling (CC) quantum dynamics calculations for collisional excitation/de-excitation of the lowest four rotational levels of OD− and of OH− interacting with Rb atoms in a cold ion trap. The calculations are carried out over a range of energies capable of yielding the corresponding rates for state-changing events over a rather broad interval of temperatures which cover those reached in earlier cold trap experiments. They involved sympathetic cooling of the molecular anion through a cloud of laser-cooled Rb atoms, an experiment which is currently being run again through a Heidelberg–Innsbruck collaboration. The significance of isotopic effects is analysed by comparing both systems and the range of temperatures examined in the calculations is extended up to 400 K, starting from a few mK. Both cross sections and rates are found to be markedly larger than in the case of OD−/OH− interacting the He atoms under the same conditions, and the isotopic effects are also seen to be rather significant at the energies examined in the present study. Such findings are discussed in the light of the observed trap losses of molecular anions

A constraint-free flight simulator package for airborne wind energy systems

Proceeding of: 7th International Conference "The Science of Making Torque from Wind" (TORQUE 2018), Milano, 20-22 June, 2018.The LAgrangian Kite SimulAtor (LAKSA) is a freely available software for the dynamic analysis of tethered flying vehicles, such as kites and fixed-wing drones, applied to airborne wind energy generation. This software comprises four simulators. The one, two and four-line simulators, which consider flexible but inelastic tethers, are based on minimal coordinate Lagragian formulations and can be used for the analysis of fly and ground generation systems, kite-based traction systems, and kitesurfing applications, respectively. The configuration of the mechanical system in the fourth simulator can be defined by the user, who can select the number of flying vehicles and the properties of the elastic and flexible tethers linking them. In all the software tools, the kites or tethered fixed-wing drones are represented as rigid bodies and the dynamic equations of the tether-bridle-vehicle systems, together with the user-defined and time-dependent control variables, are solved self-consistently. Academic and research analysis can take advantage of the modularity of the simulators and their inputs and outputs interfaces, which follow a common and user-friendly architecture.This work was supported by the Ministerio de Economía, Industria y Competitividad of Spain and the European Regional Development Fund under the project ENE2015-69937-R (MINECO/FEDER, UE). GSA work is supported by the Ministerio de Economía, Industria y Competitividad of Spain under the Grant RYC-2014-15357. RS is acknowledging the receipt of funding from the European Unions Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 642682 for the ITN project AWESCO and the grant agreement No. 691173 for the Fast Track to Innovation project REACH.Publicad