AliEnFS - a Linux File System for the AliEn Grid Services

Among the services offered by the AliEn (ALICE Environment http://alien.cern.ch) Grid framework there is a virtual file catalogue to allow transparent access to distributed data-sets using various file transfer protocols. $alienfs$ (AliEn File System) integrates the AliEn file catalogue as a new file system type into the Linux kernel using LUFS, a hybrid user space file system framework (Open Source http://lufs.sourceforge.net). LUFS uses a special kernel interface level called VFS (Virtual File System Switch) to communicate via a generalised file system interface to the AliEn file system daemon. The AliEn framework is used for authentication, catalogue browsing, file registration and read/write transfer operations. A C++ API implements the generic file system operations. The goal of AliEnFS is to allow users easy interactive access to a worldwide distributed virtual file system using familiar shell commands (f.e. cp,ls,rm ...) The paper discusses general aspects of Grid File Systems, the AliEn implementation and present and future developments for the AliEn Grid File System.Comment: 9 pages, 12 figure

The AliEn system, status and perspectives

AliEn is a production environment that implements several components of the Grid paradigm needed to simulate, reconstruct and analyse HEP data in a distributed way. The system is built around Open Source components, uses the Web Services model and standard network protocols to implement the computing platform that is currently being used to produce and analyse Monte Carlo data at over 30 sites on four continents. The aim of this paper is to present the current AliEn architecture and outline its future developments in the light of emerging standards.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 10 pages, Word, 10 figures. PSN MOAT00

Enhancing thermoelectric properties of graphene quantum rings

We study the thermoelectric properties of rectangular graphene rings connected symmetrically or asymmetrically to the leads. A side-gate voltage applied across the ring allows for the precise control of the electric current flowing through the system. The transmission coefficient of the rings manifests Breit-Wigner line-shapes and/or Fano line-shapes, depending on the connection configuration, the width of nanoribbons forming the ring and the side-gate voltage. We find that the thermopower and the figure of merit are greatly enhanced when the chemical potential is tuned close to resonances. Such enhancement is even more pronounced in the vicinity of Fano like anti-resonances which can be induced by a side-gate voltage independently of the geometry. This opens a possibility to use the proposed device as a tunable thermoelectric generator.Comment: 6 pages, 5 figures, accepted for publication in Physical Review

Conservation Laws in Smooth Particle Hydrodynamics: the DEVA Code

We describe DEVA, a multistep AP3M-like-SPH code particularly designed to study galaxy formation and evolution in connection with the global cosmological model. This code uses a formulation of SPH equations which ensures both energy and entropy conservation by including the so-called \bn h terms. Particular attention has also been paid to angular momentum conservation and to the accuracy of our code. We find that, in order to avoid unphysical solutions, our code requires that cooling processes must be implemented in a non-multistep way. We detail various cosmological simulations which have been performed to test our code and also to study the influence of the \bn h terms. Our results indicate that such correction terms have a non-negligible effect on some cosmological simulations, especially on high density regions associated either to shock fronts or central cores of collapsed objects. Moreover, they suggest that codes paying a particular attention to the implementation of conservation laws of physics at the scales of interest, can attain good accuracy levels in conservation laws with limited computational resources.Comment: 36 pages, 10 figures. Accepted for publication in The Astrophysical Journa

On the formation of tropical rings of atomic halogens: Causes and implications

Halogens produced by ocean biological and photochemical processes reach the tropical tropopause layer (TTL), where cold temperatures and the prevailing low ozone abundances favor the diurnal photochemical enhancement of halogen atoms. Under these conditions atomic bromine and iodine are modeled to be the dominant inorganic halogen species in the sunlit TTL, surpassing the abundance of the commonly targeted IO and BrO radicals. We suggest that due to the rapid photochemical equilibrium between halogen oxides and halogen atoms a natural atmospheric phenomenon evolves, which we have collectively termed >tropical rings of atomic halogens.> We describe the main causes controlling the modeled appearance and variability of these superposed rings of bare bromine and iodine atoms that circle the tropics following the Sun. Some potential implications for atmospheric oxidizing capacity are also explored. Our model results suggest that if experimentally confirmed, the extent and intensity of the halogen rings would directly respond to changes in oceanic halocarbon emissions, their atmospheric transport, and photochemistry.Peer Reviewe

The ASSET project as a training tool for energy transition

[EN] The ASSET project aims to provide a holistic and scalable solution for research, innovation and education by creating functional networks. These networks are intended to be created between energy companies, universities, training actors, energy and environmental authorities, policy makers and, more generally, citizens who are sensitive to environmental issues and the quality of energy transition processes. The ASSET project delivers the framework and the tools to create and share knowledge and competences needed to tackle the energy transition by supporting training. As a highlight of this approach to education, a strong interdisciplinary component oriented to social sciences is added in an area with an exclusive technological vocation. This transition seeks to push towards a low-carbon society in order to make the energy sector sustainable. To reach this goal, ASSET intends to strengthen the skills of sector operators, to cultivate new talents with multidisciplinary skills, and to intensify research and network industry. Therefore, the final target is to promote innovation and strengthen understanding of the importance of reducing carbon emissions. Over the course of the project, 23 learning graph models and more than 40 educational programs are being developed, in addition to a portfolio of challenges and case studies on the subject. The actors involved will be able to search for the programs available - online and on-campus - on the ASSET website and if a search is unsuccessful, a request can be sent for the creation of content necessary for their target market. The main tools that have been developed through the ASSET project are; the Learning Graph tool, the Marketplace tool and the EMMA platform. The Learning graph tool allows for the creation and sharing of learning structures, as well as the use of existing study materials. The Marketplace tool allows the searching through the available training offer, to request courses on demand, or to offer own training programmes. Finally, the EMMA platform offers a wide range of MOOC (Massive Online Open Courses), mainly in English and with the possibility of being translated into several languages. Universitat Politècnica València (UPV) is participating in the project as one of the academic actors that is developing courses and MOOCs in the area of Energy Storage. In this way, the UPV contributes to the identification of learning needs, the application of the ASSET method and tools to its teaching material, and the delivery of this teaching material. Specifically, the course being developed is called "Hydrogen as an Energy Vector". The course provides the fundamentals of hydrogen technology, using it to store energy and further develop the concept of its use as an energy vector. The course follows the blended format, combining online elements, through a MOOC (EMMA platform) and face-to-face teaching carried out at the university facilities. In the paper, we will present the main ASSET tools, the lessons learned in the development of course materials during the lifetime project and the analysis of the results of this experience.This work was supported by the European Commission though the project A Holistic And Scalable Solution For Research, Innovation And Education In Energy Transition (European Union's Horizon 2020 research and innovation programme under grant agreement number 837854).Zúñiga Saiz, P.; Sánchez-Diaz, C. (2021). The ASSET project as a training tool for energy transition. IATED Academy. 4354-4363. https://doi.org/10.21125/inted.2021.08884354436