49 research outputs found

    Ab Initio Carr-Parrinello Simulations of High Temperature GeO 2 : a comparison of the effects of plane waves cut-off and time step choice

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    Ab initio Carr-Parrinello simulations of high temperature GeO 2 have been carried out using a set of different parameters supposedly significantly affecting the results, as well as the computing times. A particular attention has been paid to the effects related with the plane waves cut-off using lower and higher values than commonly suggested. Comparisons of the results for the different values are presented and illustrated indicating that the results are essentially the same

    Hydrogen Desorption from Mg Hydride: An Ab Initio Study

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    Hydrogen desorption from hydride matrix is still an open field of research. By means of accurate first-principle molecular dynamics (MD) simulations an Mg–MgH2 interface is selected, studied and characterized. Electronic structure calculations are used to determine the equilibrium properties and the behavior of the surfaces in terms of structural deformations and total energy considerations. Furthermore, extensive ab-initio molecular dynamics simulations are performed at several temperatures to characterize the desorption process at the interface. The numerical model successfully reproduces the experimental desorption temperature for the hydride

    b-Initio Molecular Dynamics Simulation of High Temperature GeO2

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    We made a series of molecular dynamic simulations to get a representative, high temperature GeO2 system to eventually be quenched down to room temperature so as to obtain an amorphous system to be studied under pressure for comparison to experimental results. We carefully generated an initial configuration such that all simulations have entirely been carried out by ab-initio methods in the range 10K-3000K

    First-principles study of amorphous germanium under pressure

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    In this paper we present the study of the modifications of structural propertiesof a-Ge due to the application of external pressure. The investigations are carried out in the framework of density functional theory via first-principles molecular dynamics (FPMD)

    Crystalline and liquid Si3 N4 characterization by first-principles molecular dynamics simulations

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    Silicon nitride (Si3 N4 ) has a wide range of engineering applications where its mechanical and electronic properties can be effectively exploited. In particular, in the microelectronics field, the amorphous silicon nitride films are widely used as charge storage layer in metal-alumina-nitrideoxide nonvolatile memory devices. Atomic structure of amorphous silicon nitride is characterized by an high concentration of traps that control the electric behavior of the final device by the trappingde-trapping mechanism of the electrical charge occurring in its traps. In order to have a deep understanding of the material properties and, in particular, the nature of the electrical active traps a detailed numerical characterization of the crystalline and liquid phases is mandatory. For these reasons first-principles molecular dynamics simulations are extensively employed to simulate the crystalline Si3 N4 in its crystalline and liquid phases. Good agreement with experimental results is obtained in terms of density and formation entalpy. Detailed characterization of c-Si3 N4 electronic properties is performed in terms of band structure and band gap. Then constant temperature and constant volume first-principles molecular dynamics is used to disorder a stoichiometric sample of Si3 N4 . Extensive molecular dynamics simulations are performed to obtain a reliable liquid sample whose atomic structure does not depend on the starting atomic configuration. Detailed characterization of the atomic structure is achieved in terms of radial distribution functions and total structure factor

    3cixty: Building comprehensive knowledge bases for city exploration

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    International audiencePlanning a visit to Expo Milano 2015 or simply touring in Milan are activities that require a certain amount of a priori knowledge of the city. In this paper, we present the process of building such comprehensive knowledge bases that contain descriptions of events and activities, places and sights, transportation facilities as well as social activities, collected from numerous static, near-and real-time local and global data providers, including hyper local sources such as the Expo Milano 2015 official services and several social media platforms. Entities in the 3cixty KB are deduplicated, interlinked and enriched using semantic technologies. The 3cixty KB is empowering the ExplorMI 360 multi-device application, which has been officially endorsed by the E015 Technical Management Board and has gained the patronage of Expo Milano in 2015, thus has offered a unique testing scenario for the 20 million visitors along the 6 months of the exhibit. In 2016-2017, new knowledge bases have been created for the cities of London, Madeira and Singapore, as well as for the entire French Cote d'Azur area. The 3cixty KB is accessible at https: //kb.3cixty.com/sparql while ExplorMI 360 at https://www.3cixty.com and in the Google Play Store and Apple App Store

    FAIR Metadata Standards for Low Carbon Energy Research—A Review of Practices and How to Advance

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    The principles of Findability, Accessibility, Interoperability, and Reusability (FAIR) have been put forward to guide optimal sharing of data. The potential for industrial and social innovation is vast. Domain-specific metadata standards are crucial in this context, but are widely missing in the energy sector. This report provides a collaborative response from the low carbon energy research community for addressing the necessity of advancing FAIR metadata standards. We review and test existing metadata practices in the domain based on a series of community workshops. We reflect the perspectives of energy data stakeholders. The outcome is reported in terms of challenges and elicits recommendations for advancing FAIR metadata standards in the energy domain across a broad spectrum of stakeholders

    3cixty@Expo Milano 2015: Enabling Visitors to Explore a Smart City

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    -Planning a visit to Expo Milano 2015 or simply touring in Milan are activities that require a certain amount of a priori knowledge of the city. In this paper, we present the process of building such a comprehensive knowledge base, the 3cixty KB, that contains descriptions of events, places, transportation facilities and social activities, collected from numerous static, near-and real-time local and global data providers, including Expo Milano 2015 official services and several social media platforms. Entities in the 3cixty KB are deduplicated, interlinked and enriched using semantic technologies. The 3cixty KB is empowering the Ex-plorMI 360 multi-device application, which has been officially endorsed by the E015 Technical Management Board and has gained the patronage of Expo Milano 2015, thus offering a unique testing scenario for the 20 million expected visitors along the 6 months of the exhibit. As of Septem-ber 7th, 2015 the 3cixty KB contains unique descriptions of 18, 665 events, 758 artists, 225, 552 places, 9, 342 transportation facilities, 95, 570 illustrating photos and 94, 789 reviews contributed by 81, 944 users. The 3cixty KB is accessible at http://3cixty.eurecom.fr/sparql while Ex-plorMI 360 at https://www.3cixty.com

    TEXTAROSSA: Towards EXtreme scale Technologies and Accelerators for euROhpc hw/Sw Supercomputing Applications for exascale

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    International audienceTo achieve high performance and high energy efficiency on near-future exascale computing systems, three key technology gaps needs to be bridged. These gaps include: energy efficiency and thermal control; extreme computation efficiency via HW acceleration and new arithmetics; methods andtools for seamless integration of reconfigurable accelerators in heterogeneous HPC multi-node platforms. TEXTAROSSA aims at tackling this gap through a co-design approach to heterogeneous HPC solutions, supported by the integration and extension of HW and SW IPs, programming models and tools derived from European research
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