Comparison of the estimated modalparameters of structures from classical and operational modalanalysis with mass changes

La falta de normalización en los resultados de los modos de vibración, ha sido la principal desventaja del análisis modal operacional, resuelto posteriormente mediante el método de modificación de masa, el cual supone un gran inconveniente para las obras civiles, ya que interrumpe el tráfico sobre las mismas, incrementando el tiempo del ensayo y notablemente su coste. El objeto de este trabajo radica en efectuar un balance entre: el análisis modal tradicional (acompañado de simulaciones numéricas de la modificación de masa), frente al análisis modal operacional (conjuntamente con el método de modificación de masa); obteniendo unos resultados más óptimos y con un rango de error menor, incluso con la presencia de un alto nivel de ruido en la señal De esta forma es posible, conocer de la forma más fiable, los parámetros modales de la estructura, y su alteración con la modificación de masa. Para ello se aplica la metodología expuesta a un puente metálico de gran luz, singular por su esbeltez, con una relación luz/canto de 56.6, la menor registrada en un puente, y que lo ha hecho figurar desde el año 2007 en el Libro Guinnes de los records.The lack of standardization in vibration mode results has constituted the main shortcoming of operational modal analysis, subsequently resolved by means of the mass modification method. This is a major drawback for civil works, as it interrupts traffic on site, significantly increasing testing time and costs. The purpose of this study is to achieve a balance between traditional modal analysis (accompanied by numerical simulations of mass modification) and operational modal analysis (in conjunction with the mass modification method), thereby obtaining more optimal results with a narrower range of error, even when the signal has a high level of noise. It will thus be possible to reliably determine the modal parameters of the structure and their alteration due to mass modification. For this purpose, the proposed methodology is applied to a large span metal bridge, unique for its slenderness, with a span/depth ratio of 56.6, the lowest recorded on a bridge, as figured in the Guinness Book of Records since 2007.Peer Reviewe

Psicobiología y educación.

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Insights on the acting role of Martian atmosphere in the fragmentation pathways of organic and C-containing inorganic compounds using LIBS

In the present work, a preliminary fundamental study about the influence of background gas in Martian surface conditions (CO2, P=7 mbar) on the formation of emitting species in laser-induced plasmas of ablated C-containing compounds was performed. Results were compared with those obtained using ambient air as surrounding gas of irradiated samples. Energy thresholds were evaluated for excited atomic and molecular species of interest resulting in the plasma using a home-made LIBS system coupled to a pressure chamber for simulating Martian environment during the analysis of samples. Inorganic salts as calcium carbonate and magnesium carbonate besides pyrene as organic reference compound were analyzed in order to discern the origin of C-containing species coexisting in the plasma plume (C, C2 and CN, mainly). Results from acquired emission spectra shed light on the different carbon sources of emitting species as a function of energetic and pressure conditions.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Applications of the complexity space to the General Probabilistic Divide and Conquer Algorithms

AbstractSchellekens [M. Schellekens, The Smyth completion: A common foundation for denotational semantics and complexity analysis, in: Proc. MFPS 11, in: Electron. Notes Theor. Comput. Sci., vol. 1, 1995, pp. 535–556], and Romaguera and Schellekens [S. Romaguera, M. Schellekens, Quasi-metric properties of complexity spaces, Topology Appl. 98 (1999) 311–322] introduced a topological foundation to obtain complexity results through the application of Semantic techniques to Divide and Conquer Algorithms. This involved the fact that the complexity (quasi-metric) space is Smyth complete and the use of a version of the Banach fixed point theorem and improver functionals. To further bridge the gap between Semantics and Complexity, we show here that these techniques of analysis, based on the theory of complexity spaces, extend to General Probabilistic Divide and Conquer schema discussed by Flajolet [P. Flajolet, Analytic analysis of algorithms, in: W. Kuich (Ed.), 19th Internat. Colloq. ICALP'92, Vienna, July 1992; Automata, Languages and Programming, in: Lecture Notes in Comput. Sci., vol. 623, 1992, pp. 186–210]. In particular, we obtain a general method which is useful to show that for several recurrence equations based on the recursive structure of General Probabilistic Divide and Conquer Algorithms, the associated functionals have a unique fixed point which is the solution for the corresponding recurrence equation