Perturbation of the sierpinski antenna to allocate the operating bands

A scheme for modifying the spacing between the bands of the Sierpinski antenna is introduced. Experimental results of two novel designs of fractal antennas suggest that the fractal structure can be perturbed to enable the log-period to be changed while still maintaining the multiband behaviour of the antenna.Peer ReviewedPostprint (published version

Interrogantes educativos desde la sociedad del conocimiento

La Sociedad del conocimiento y la forma como hoy gestionamos la información se han traducido en la introducción de las TICs en el sistema educativo, incorporando muchas veces la terminología (Escuela 2.0, aprendizaje digital, ) pero no los auténticos cambios que esas tecnologías han provocado en la Sociedad y, por ende, en nuestros estudiantes. En este artículo se plantean 9 de los temas más relevantes que son objeto de discusión social: la autoridad del experto cuestionada por la inteligencia colectiva, la superficialidad del conocimiento denunciada por Carr, la inestabilidad de los documentos y de sus contenidos sujetos a cambio en cualquier momento, la inabarcabilidad de la información que hace "imposible incluso al especialista estar al día", los derechos del autor y el propio concepto de autor en la era de la "segunda oralidad", la democracia informativa como alternativa al "cuarto poder", el acceso global superando fronteras, el respeto a la privacidad y la identidad digital. Frente a esos temas la escuela o la universidad introducen las tecnologías sin alterar su modelo ni sus prácticas. El objetivo final de este texto es invitar a los educadores a reflexionar sobre su práctica docente

Achieving a "SIL 1" TCR Monitoring System

SIL 1 (Safety Integrity Level 1) refers to the quantification and measurement of the availability, reliability, maintenance and safety of the monitoring system. In the last few years the computer infrastructure used to acquire and to diffuse data to the TCR has evolved very rapidly. A number of measures in hardware, software and management have been introduced to cope with this situation. These include: the Multipurpose Monitoring Device (MMD), a standard data acquisition platform used in the renovation of old front end monitoring equipment, the Smart Equipment Controller (Dsec), a driver that reduces the layers in the data diffusion pyramid, the multiplatform monitoring software to integrate the different SCADA systems, a software configuration tool (RAZOR) for problem tracking and version control, and a complete development environment reproducing a real installation for thorough testing of any changes. To achieve SIL 1 objectives, while mastering the evolution of our systems will be the challenge for the computer team

Quadrupolar XMCD at the Fe K -edge in Fe phthalocyanine film on Au: Insight into the magnetic ground state

Under the terms of the Creative Commons Attribution license.-- et al.The observation of an anomalous quadrupolar signal in x-ray magnetic circular dichroism (XMCD) at the Fe K-edge of iron phthalocyanine (FePc) films is reported. All ground states previously suggested for FePc are incompatible with the experimental data. Based on ab initio molecular orbital multiplet calculations of the isolated FePc molecule, we propose a model for the magnetic ground state of the FePc film that explains the XMCD data and reproduces the observed values of the orbital moments in the perpendicular and planar directions.The financial support of the Spanish financial agency MINECO MAT2011-23791 and MAT2014-53921-R, Aragonese DGA-IMANA E34 (co-funded by Fondo Social Europeo), and European Union FEDER funds is acknowledged. The research at UCSD was supported by the Office of Basic Energy Science, US Department of Energy, BES-DMS, funded by the Department of Energy Office of Basic Energy Science, DMR, under Grant No. DE FG03 87ER-45332.Peer Reviewe

Zero-temperature spin-glass freezing in self-organized arrays of Co nanoparticles

We study, by means of magnetic susceptibility and magnetic aging experiments, the nature of the glassy magnetic dynamics in arrays of Co nanoparticles, self-organized in N layers from N=1 (two-dimensional limit) up to N=20 (three-dimensional limit). We find no qualitative differences between the magnetic responses measured in these two limits, in spite of the fact that no spin-glass phase is expected above T=0 in two dimensions. More specifically, all the phenomena (critical slowing down, flattening of the field-cooled magnetization below the blocking temperature and the magnetic memory induced by aging) that are usually associated with this phase look qualitatively the same for two-dimensional and three-dimensional arrays. The activated scaling law that is typical of systems undergoing a phase transition at zero temperature accounts well for the critical slowing down of the dc and ac susceptibilities of all samples. Our data show also that dynamical magnetic correlations achieved by aging a nanoparticle array below its superparamagnetic blocking temperature extend mainly to nearest neighbors. Our experiments suggest that the glassy magnetic dynamics of these nanoparticle arrays is associated with a zero-temperature spin-glass transition.Comment: 6 pages 6 figure

TCR industrial system integration strategy

New turnkey data acquisition systems purchased from industry are being integrated into CERN's Technical Data Server. The short time available for system integration and the large amount of data per system require a standard and modular design. Four different integration layers have been defined in order to easily 'plug in' industrial systems. The first layer allows the integration of the equipment at the digital I/O port or fieldbus (Profibus-DP) level. A second layer permits the integration of PLCs (Siemens S5, S7 and Telemecanique); a third layer integrates equipment drivers. The fourth layer integrates turnkey mimic diagrams in the TCR operator console. The second and third layers use two new event-driven protocols based on TCP/IP. Using this structure, new systems are integrated in the data transmission chain, the layer at which they are integrated depending only on their integration capabilities