18 research outputs found

    Knowledge-based collaboration in construction industry

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    The present paper focuses on the topic of Communities & Networks but it also covers some issues on Collaborative Enterprises, Collaborative Processes & Workspaces, and Business to Business Networks. It is based mainly on the Collective project Know Construct (COLL-CT-2004-500276) starting in March 2005. The project aims to develop a common internet-based platform for SMEs from the construction sector to provide an effective combination of two general functionalities: an innovative decision making support system regarding the products characteristics, applications and other consultancy services for SMEs' customers applying the ldquoweb enabled dialoguerdquo, and a system for SMEs to support an advanced form of co-operation through the creation of Knowledge Communities of SMEs in Construction Industry. The system supports the integration, management and reuse of the area specific knowledge via a common knowledge base. The system is intended to be used within the Associations to collect and exchange the business area specific knowledge among the members (SMEs) in a form of essential expertise, reachable anywhere, at any time

    PlanetCam UPV/EHU: a two-channel lucky imaging camera for solar system studies in the spectral range 0.38-1.7 µm

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    This is an author-created, un-copyedited version of an article published in Publications of the Astronomical Society of the Pacific. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it.We present PlanetCam UPV/EHU, an astronomical camera designed fundamentally for high-resolution imaging of Solar System planets using the “lucky imaging” technique. The camera observes in a wavelength range from 380 nm to 1.7 µm and the driving science themes are atmosphere dynamics and vertical cloud structure of Solar System planets. The design comprises two configurations that include one channel (visible wavelengths) or two combined channels (visible and short wave nfrared) working simultaneously at selected wavelengths by means of a dichroic beam splitter. In this paper the camera components for the two configurations are described, as well as camera performance and the different tests done for the precise characterization of its radiometric and astrometric capabilities at high spatial resolution. Finally, some images of solar system objects are presented as well as photometric results and different scientific cases on astronomical targets.Peer ReviewedPostprint (author's final draft

    OC5 Project Phase II: Validation of Global Loads of the DeepCwind Floating Semisubmersible Wind Turbine

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    This paper summarizes the findings from Phase II of the Offshore Code Comparison, Collaboration, Continued, with Correlation project. The project is run under the International Energy Agency Wind Research Task 30, and is focused on validating the tools used for modeling offshore wind systems through the comparison of simulated responses of select system designs to physical test data. Validation activities such as these lead to improvement of offshore wind modeling tools, which will enable the development of more innovative and cost-effective offshore wind designs. For Phase II of the project, numerical models of the DeepCwind floating semisubmersible wind system were validated using measurement data from a 1/50th-scale validation campaign performed at the Maritime Research Institute Netherlands offshore wave basin. Validation of the models was performed by comparing the calculated ultimate and fatigue loads for eight different wave-only and combined wind/wave test cases against the measured data, after calibration was performed using free-decay, wind-only, and wave-only tests. The results show a decent estimation of both the ultimate and fatigue loads for the simulated results, but with a fairly consistent underestimation in the tower and upwind mooring line loads that can be attributed to an underestimation of waveexcitation forces outside the linear wave-excitation region, and the presence of broadband frequency excitation in the experimental measurements from wind. Participant results showed varied agreement with the experimental measurements based on the modeling approach used. Modeling attributes that enabled better agreement included: the use of a dynamic mooring model; wave stretching, or some other hydrodynamic modeling approach that excites frequencies outside the linear wave region; nonlinear wave kinematics models; and unsteady aerodynamics models. Also, it was observed that a Morison-only hydrodynamic modeling approach could create excessive pitch excitation and resulting tower loads in some frequency bands.This work was supported by the U.S. Department of Energy under Contract No. DEAC36- 08GO28308 with the National Renewable Energy Laboratory. Some of the funding for the work was provided by the DOE Office of Energy Efficiency and Renewable Energy, Wind and Water Power Technologies Office

    OC6 Phase II: Integration and verification of a new soil–structure interaction model for offshore wind design

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    This paper provides a summary of the work done within the OC6 Phase II project, which was focused on the implementation and verification of an advanced soil–structure interaction model for offshore wind system design and analysis. The soil–structure interaction model comes from the REDWIN project and uses an elastoplastic, macroelement model with kinematic hardening, which captures the stiffness and damping characteristics of offshore wind foundations more accurately than more traditional and simplified soil–structure interaction modeling approaches. Participants in the OC6 project integrated this macroelement capability to coupled aero-hydro-servo-elastic offshore wind turbine modeling tools and verified the implementation by comparing simulation results across the modeling tools for an example monopile design. The simulation results were also compared to more traditional soil–structure interaction modeling approaches like apparent fixity, coupled springs, and distributed springs models. The macroelement approach resulted in smaller overall loading in the system due to both shifts in the system frequencies and increased energy dissipation. No validation work was performed, but the macroelement approach has shown increased accuracy within the REDWIN project, resulting in decreased uncertainty in the design. For the monopile design investigated here, that implies a less conservative and thus more cost-effective offshore wind design.US Department of Energy Office of Energy Efficiency and Renewable Energy Wind Energy Technologies Office, Grant/Award Number: DE-AC36-08GO2830

    OC6 project phase III : validation of the aerodynamic loading on a wind turbine rotor undergoing large motion caused by a floating support structure

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    This paper provides a summary of the work done within Phase III of the Offshore Code Comparison, Collaboration, Continued, with Correlation and unCertainty project (OC6), under International Energy Agency Wind Task 30. This phase focused on validating the aerodynamic loading on a wind turbine rotor undergoing large motion caused by a floating support structure. Numerical models of the Danish Technical University 10-MW reference wind turbine were validated using measurement data from a 1:75 scale test performed during the UNsteady Aerodynamics for FLOating Wind (UNAFLOW) project and a follow-on experimental campaign, both performed at the Politecnico di Milano wind tunnel. Validation of the models was performed by comparing the loads for steady (fixed platform) and unsteady wind conditions (harmonic motion of the platform). For the unsteady wind conditions, the platform was forced to oscillate in the surge and pitch directions under several frequencies and amplitudes. These oscillations result in a wind variation that impacts the rotor loads (e.g., thrust and torque). For the conditions studied in these tests, the system mainly described a quasi-steady aerodynamic behavior. Only a small hysteresis in airfoil performance undergoing angle of attack variations in attached flow was observed. During the experiments, the rotor speed and blade pitch angle were held constant. However, in real wind turbine operating conditions, the surge and pitch variations would result in rotor speed variations and/or blade pitch actuations depending on the wind turbine controller region that the system is operating. Additional simulations with these control parameters were conducted to verify the fidelity between different models. Participant results showed in general a good agreement with the experimental measurements and the need to account for dynamic inflow when there are changes in the flow conditions due to the rotor speed variations or blade pitch actuations in response to surge and pitch motion. Numerical models not accounting for dynamic inflow effects predicted rotor loads that were 9 % lower in amplitude during rotor speed variations and 18 % higher in amplitude during blade pitch actuations

    Numerical Approaches for Loads and Motions Assessment of Floating WECs Moored by Means of Catenary Mooring Systems

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    Technologies for harvesting offshore renewable energy based on floating platforms, such as offshore wind, wave and tidal energies, are currently being developed with the purpose of achieving a competitive cost of energy. The economic impact of the mooring system is significant within the total cost of such deployments, and large efforts are being carried out to optimize designs. Analysis of mooring systems at early stages generally require a trade-off between quick analysis methods and accuracy to carry out multi-variate sensitivity analyses. Even though the most accurate approaches are based on the non-linear finite element method in the time domain, these can result in being very time consuming. The most widely used numerical approaches for mooring line load estimates are introduced and discussed in this paper. It is verified that accurate line tension estimates require lines drag and inertia forces to be accounted for. A mooring and floating structure coupled model based on the lumped mass finite element approach is also discussed, and it is confirmed that the differences found in the coupled numerical model are mainly produced by the uncertainty on hydrodynamic force estimates on the floating structure rather than by the lumped mass method. In order to enable quick line tension estimates, a linearization of the structure and mooring coupled model is discussed. It shows accurate results in operational conditions and enables modal analysis of the coupled system.This work was funded by Project IT949-16 (Departamento de Educación, Política Lingüística y Cultura, Regional). Government of the Basque Country

    Mooring System Design Approach: A Case Study for MARMOK-A Floating OWC Wave Energy Converter

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    This paper presents a methodology and a flowchart of steps to take for a, consistent and rapidly convergent design of catenary mooring systems. It is subsequently applied for a floating Oscillating Water Column WEC MARMOK-A developed by Oceantec Energías Marinas, in order to fulfill the technical requirements of such dynamic systems. The approach, based on the catenary equations, considers the water depth as a design scale factor for the mooring system, leading to an equivalent static mooring performance. In general, a mooring system configuration is described by the number and distribution of lines; thus, as a preprocess in the herein described procedure, a database is built for different line lengths. The main advantage of the procedure is that once that, after characterizing a mooring system configuration at a specific water depth with a specific line mass and axial stiffness, the database built can be used for any other water depth with any line mass and axial stiffness, accelerating the design optimization process. Mooring static properties are derived for a given material elastic modulus, lines’ mass and water depth. The mean offset and horizontal stiffness are afterwards derived with lines pretension and steady environmental forces (mean wave drift, current and wind) as well as maximum offset and characteristic line tensions. Finally, the process is applied for different lines pretensions to achieve an objective horizontal stiffness of the structure. The introduced procedure is presented through its application to the MARMOK-A device at a 90m depth site moored by means of a Karratu named mooring configuration. Results are presented in terms of total lines mass, device maximum expected excursion and required footprint for different horizontal stiffness and lines mass in order to give an insight of the impact on total plant cost indicators

    Integración : revista sobre ceguera y deficiencia visual

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    Resumen en inglés y castellanoSe presenta, como prototipo, una aplicación de realidad virtual que permite a las personas ciegas interactuar con los gráficos de ordenador mediante el tacto. Se trata de una herramienta que posibilita explorar con el tacto objetos y espacios virtuales en tres dimensiones y tener sensación de profundidad, densidad, rugosidad, magnitud. Esta nueva herramienta consta de dos módulos diferentes: módulo de reconocimiento de entornos interiores y módulo de comandos táctiles. El primero de ellos permite el reconocimiento de entornos interiores (oficinas, casas, etc) por medio de un instrumento, inicialmente una especie de dedal y en un futuro un guante; las personas ciegas pueden por ejemplo detectar y subir los peldaños de una escalera, desplazarse por las habitaciones de una casa, reconocer la mesa y la silla del salón y percibir su forma, tamaño y textura. El módulo de comandos táctiles permite el control de las aplicaciones mediante paneles de comandos/botones a los que el usuario puede acceder con el tacto, evitando de esta forma el procedimiento actual de ratón-iconos que no es válido para las personas ciegas..MadridES

    PlanetCam UPV/EHU: a two-channel lucky imaging camera for solar system studies in the spectral range 0.38-1.7 µm

    No full text
    This is an author-created, un-copyedited version of an article published in Publications of the Astronomical Society of the Pacific. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it.We present PlanetCam UPV/EHU, an astronomical camera designed fundamentally for high-resolution imaging of Solar System planets using the “lucky imaging” technique. The camera observes in a wavelength range from 380 nm to 1.7 µm and the driving science themes are atmosphere dynamics and vertical cloud structure of Solar System planets. The design comprises two configurations that include one channel (visible wavelengths) or two combined channels (visible and short wave nfrared) working simultaneously at selected wavelengths by means of a dichroic beam splitter. In this paper the camera components for the two configurations are described, as well as camera performance and the different tests done for the precise characterization of its radiometric and astrometric capabilities at high spatial resolution. Finally, some images of solar system objects are presented as well as photometric results and different scientific cases on astronomical targets.Peer Reviewe
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