Advanced representation of tubular joints in jacket models for offshore wind turbine simulation

Jacket substructures for offshore wind turbines show strong potentials in water depths from 25 up to 70m. A review of state-of-practice and enhanced state-of-the-art modeling of offshore wind turbine jackets is conducted regarding detailed joint properties. The state-of-the-art approach takes advantage of an accurate description of the local joint behavior by use of superelements, enabling more accurate load simulations. Studies conducted in the past highlighted both strong benefits as well as shortcomings of this approach, whereas the drawbacks were mainly related to the size of superelements and the application of local wave loading. This work develops a smart sizing for detailed joint models taking into account the loading and location of the jacket joints. A concept of local wave loading is presented as well. Advice on recommendable parameters is given and enables an optimized superelement application for jacket substructures. As an example the potential for fatigue load reduction is shown using the NREL offshore 5-MW baseline wind turbine and the OC4 reference jacket. The predicted fatigue lifetime was increased by about 15%.Research Council of Norwa

Semiclassical Lindblad master equation for spin dynamics

We derive the semi-classical Lindblad master equation in phase space for both canonical and non-canonical Poisson brackets using the Wigner-Moyal formalism and the Moyal star-product. The semi-classical limit for canonical dynamical variables, i.e., canonical Poisson brackets, is the Fokker-Planck equation, as derived before. We generalize this limit and show that it holds also for non-canonical Poisson brackets. Examples are gyro-Poisson brackets, which occur in spin ensembles, systems of recent interest in atomic physics and quantum optics. We show that the equations of motion for the collective spin variables are given by the Bloch equations of nuclear magnetization with relaxation. The Bloch and relaxation vectors are expressed in terms of the microscopic operators: The Hamiltonian and the Lindblad functions in the Wigner-Moyal formalism

A measurement-based measure of the size of macroscopic quantum superpositions

Recent experiments claiming formation of quantum superposition states in near macroscopic sys- tems raise the question of how the sizes of general quantum superposition states in an interacting system are to be quantified. We propose here a measure of size for such superposition states that is based on what measurements can be performed to probe and distinguish the different branches of the state. The measure allows comparison of the effective size for superposition states in very different physical systems. It can be applied to a very general class of superposition states and reproduces known results for near-ideal cases. Comparison with a prior measure based on analy- sis of coherence between branches indicates that significantly smaller effective superposition sizes result from our measurement-based measure. Application to a system of interacting bosons in a double-well trapping potential shows that the effective superposition size is strongly dependent on the relative magnitude of the barrier height and interparticle interaction.Comment: 21 pages, 20 figures. Accepted by Phys. Rev. A. Replaced old version with accepted version. Significant changes and improvements, particularly to section on 1-particle measurement

Terrestrial and fluvial carbon fluxes in a tropical watershed: Nyong basin, Cameroon

The Nyong watershed, with an area of 27 800 km2 and a mean annual discharge of 390 m3 s−1, is the second largest river in Cameroon. The Nyong watershed serves as an outstanding study area for the examination of carbon fluxes in humid tropical environments because of its limited anthropogenic impact and homogeneous silicate bedrock. Between April 2005 and April 2007, we sampled water at seven stations, from the small watershed of the Mengong (0.6 km2) to the Nyong at Edea (24 500 km2), and monitored temperature, pH, dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) contents, as well as the isotopic composition of DIC (δ13CDIC)andDOC(δ13CDOC).We estimated terrestrial net ecosystemproductivity in theNyong River watershed and measured fluvial fluxes of carbon to the ocean and the atmosphere. The Nyong River basin sequesters significant amounts of carbon on an annual basis: ~7 920 000t C year−1 (300 g C m−2 year−1). The combined dissolved organic, dissolved inorganic and atmospheric fluxes of carbon from the Nyong River only export 3% of this flux fromthe basin on an annual basis. This includes a minimumCO2 outgassing of 1487 g Cm−2 year−1, comparable to 115% of the annual flux of DOC and four times greater than the flux of DIC

Sistema de detección de fallas para un motor DC mediante filtros de Kalman

Las metodologías para la determinación e identificación de fallas en procesos industriales viene siendo desarrollada e investigada desde hace 30 años, en los cuales se han elaborado una gran variedad de metodologías de detección y de aplicaciones a sistemas reales. Debido al aumento de la complejidad y cantidad de los procesos que necesitan ser controlados, surgen teorías para la detección e identificación de fallas como solución a problemas de repercusión no solo económica, sino también ecológica, productiva y de seguridad. En la presente tesis se ha desarrollado un método de detección e identificación basado en una innovación proveniente del filtro de Kalman, la cual provee condiciones suficientes y necesarias para la detección de fallas aditivas bajo influencia de ruido gaussiano blanco. Esta metodología de detección se aplica a un motor de corriente contínua de excitación independiente, cuya función de transferencia tipo SISO ha sido obtenida experimentalmente. Posteriormente un análisis estadístico de la innovación obtenida del filtro de Kalman, ha permitido diagnosticar la presencia e instante de la falla aditiva generada en el sensor del sistema. Lo anterior ha generado un sistema capaz de detectar fallas aditivas idealizadas como modelos tipo escalones y rampas en un sistema lineal e invariante en el tiempo. El sistema desarrollado, permite la correcta detección e identificación de las fallas aditivas presentes en el sensor del modelo del motor de corriente continua, basándose en el análisis estadístico del parámetro innovación proveniente del Filtro de Kalman.Tesi

Strong-field photoionization by circularly polarized light

We demonstrate that strong-field ionization of atoms driven by circularly polarized light becomes an adiabatic process when described in the frame rotating with the laser field. As a direct consequence, a conservation law emerges: in the rotating frame the energy of the tunneling electron is conserved for rotationally invariant potentials. This conservation law, arising from a classical picture, is retrieved through a proper classical-quantum correspondence when considering the full quantum system, beyond the Strong Field Approximation

Gustatory responses in primates to the sweetener aspartame and their phylogenetic implications

Two-bottle preference tests have been applied to 70 (sub-) species of the order of Primates and, for comparison, to the tree shrew (Tupaia belangeri) to determine their responses to aspartame (APM), the first known sweet-tasting dipeptide which has to man a sweetness potency of about 200 times that of sucrose. It was found that only the Cercopithecidae, the Hylobatidae and the Pongidae respond like man to this dipeptide and prefer it to water. The other primates tested to date, show no response to this sweetener. From a phylogenetic point of view, we note that APM shows species specificity similar to thaumatin. Thus, a clear dichotomy exists within the order of Primates with respect to both thaumatin and APM. The results here illustrate once more the gustatory diversity among primates and are a compelling argument for the existence of different sweet taste receptors or recognition sites in primate specie

Monitoring recreation across European nature areas: A geo-database of visitor counts, a review of literature and a call for a visitor counting reporting standard

Nature recreation and tourism is a substantial ecosystem service of Europe’s countryside that has a substantial economic value and contributes considerably to income and employment of local communities. Highlighting the recreational value and economic contribution of nature areas can be used as a strong argument for the funding of protected and recreational areas. The total number of recreational visits of a nature area has been recognised as a major determinant of its economic recreational value and its contribution to local economies. This paper presents an international geodatabase on recreational visitor numbers to non-urban ecosystems, containing 1,267 observations at 518 separate case study areas throughout Europe. The monitored sites are described by their centroid coordinates and shape files displaying the exact extension of the sites. Therefore, the database illustrates the spatial distribution of visitor counting throughout Europe and can be used for secondary research, such as for validation of spatially explicit recreational ecosystem service models and for identifying relevant drivers of recreational ecosystem services. To develop the database, we review visitor monitoring literature throughout Europe and give an overview of such activities with special attention to visitor counting. We identify one major shortcoming in available literature, which relates to the presentation, study area definition and methodological reporting of conducted visitor counting studies. Insufficient reporting hampers the identification of the study area, the comparability of different studies and the evaluation of the studies’ quality. Based on our findings, we propose a standardised reporting template for visitor counting studies and advanced data sharing for recreational visitor data. Researchers and institutions are invited to report on their visitor counting studies via our web interface at rris.biopama.org/visitor-reporting to contribute to a global visitor database that will be shared via the ESP Visualisation tool (http://esp-mapping.net)

Diagnostic approach for myocardial contusion: a retrospective evaluation of patient data and review of the literature

Purpose: Myocardial contusion can be a life-threatening condition in patients who sustained blunt thoracic trauma. The diagnostic approach remains a subject of debate. The aim of this study was to determine the sensiti