1,720,997 research outputs found
Development of the instrumentation of the botafoc breakwater nº 8 caisson
Full text linkBalearic Port Authority has developed an instrumentation system for the #8 caisson of the Botafoc breakwater that integrates 12 pressure sensors located at three surfaces, two in contact with the sea water and another with the bottom. This design was completed with an inertial system that measures the angular velocities and the accelerations over the three Cartesian axes. Consequently, the system measures actions (pressures) and reactions (movements and accelerations) experimented by the caisson, due to sea waves and/or other service loads. R+D department of the Port Authority and Polytechnic University of Madrid are working on two directions, the development of new theories on vertical breakwater design that go beyond Goda and Sainflou, and on the creation of a real-time critical structure alarm system, based on the instrumentation installed. This alarm system has two main parts: the instrumentation itself that collects data and processes it on real-time (the data processing compares the pressure law suffered by the caisson in every step process with the design critical state of the caisson, in this case the Goda pressure law for a 6.5 m wave), giving a security coefficient that points out the risk level on real-time; and the alarm system consisting of a monitoring panel located in the Port Control Center that shows the risk level and advises in case of an incidental evacuation of this critical portuary installation
Pressure distribution at the front face and the bottom of a vertical breakwater in multidirectional seas
No full textAn optimal design of vertical breakwaters subject to breaking and non-breaking waves requires 3D-effects such as short-crestedness and wave obliquity to be taken into account. For design purposes the potential load reduction of these effects should be properly considered to enable a more economic design of these structures. 3D-model tests have been conducted by a European research team coordinated by University of Bologna (Italy) and composed of Aalborg (Denmark) and Braunschweig Universities (Germany) in the Coastal Research Facility (CRF) at HR Wallingford. In this paper, these tests and first results are described and compared to standard design methods available suggesting that there is an even higher decrease of forces and pressures with increasing obliquity of the waves than assumed by present design
Development of a critical structure state alarm system based on the instrumentation of the Botafoc breakwater nº 8 caisson
Full text linkBalearic Port Authority has developed an instrumentation system for the #8 caisson of the Botafoc breakwater that integrates 12 pressure sensors located at three surfaces, two in contact with the sea water and another with the bottom. This design was completed with an inertial system that measures the angular velocities and the accelerations over the three Cartesian axes. Consequently, the system measures actions (pressures) and reactions (movements and accelerations) experimented by the caisson, due to sea waves and/or other service loads. R+D department of the Port Authority and Polytechnic University of Madrid are working on two directions, the development of new theories on vertical breakwater design that go beyond Goda and Sainflou, and on the creation of a real-time critical structure alarm system, based on the instrumentation installed. This alarm system has two main parts: the instrumentation itself that collects data and processes it on real-time (the data processing compares the pressure law suffered by the caisson in every step process with the design critical state of the caisson, in this case the Goda pressure law for a 6.5 m wave), giving a security coefficient that points out the risk level on real-time; and the alarm system consisting of a monitoring panel located in the Port Control Center that shows the risk level and advises in case of an incidental evacuation of this critical portuary installation
Recent Advances in the Development of Wave Energy Converters
No full textThis paper attempts to summarize the current state of the wave energy converters worldwide, introducing the most promising devices to date and the governing processes behind their operation. This also includes an overview of existing and potential power take-off (PTO) systems for wave energy converters
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Wellenüberlaufströmung bei Seedeichen - Experimentelle und theoretische Untersuchungen
No full textWave overtopping is one of the most important processes for the design of seadikes which was responsible for many severe dike failures in the past. Wave overtopping can not be avoided due to the random nature of the waves and the uncertainties associated with the determination of the design water level. The present design on wave overtopping is based on average overtopping rates. Nevertheless, average overtopping rates are not sufficient for the design of seadikes, because overtopping velocities and overtopping layer thicknesses are required to assess the infiltration and erosion on the landward side of seadikes by overtopping water. The objective of the present thesis is the determination of the velocities and layer thicknesses on the seaward slope, the dike crest and the landward slope as a function of the relevant wave and dike parameters by means of theoretical and experimental investigations. Small scale model tests have been carried out in a wave flume with typical dike profiles by using regular waves and wave spectra. Small scale model tests are influenced by scale effects and the transfer of the results to nature might be affected. Therefore, theoretical investigations on the influence of viscosity and surface tension on the model results are performed. It can be concluded that the results of the present study are not significantly influenced by scale effects and can be transfered to prototype scale. Wave overtopping is dependent on the processes associated to wave breaking and wave run-up on the seaward slope. Therefore, these processes are investigated first. Breaker type, breaking water depth, wave run-up height, wave run-down and the impact point of the breaking wave on the seaward slope are determined and described by means of empirical equations. The main part of this thesis is the determination of layer thicknesses and velocities on the seaward slope, the dike crest and the landward slope. Layer thickness and wave run-up velocities on the seaward slope are closely connected to the wave run-up height. Empirical formulae for layer thicknesses and a theoretical approach for overtopping velocities are derived for the dike crest. Overtopping velocities and layer thicknesses on the landward slope are derived on the basis of the two-dimensional momentum equation and the continuity equation. All derived formulae are calibrated by model tests with regular waves and verified by model tests with wave spectra
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Breaching of coastal dikes: State of the art
No full textCoastal dikes are used as defence structures against flooding in lowland areas and where high tidal ranges occur. The development of a breach induced by wave overtopping has been one of the most frequent causes of dike failure and it is closely related both to the dynamics of a protected coast and to the flood risk assessment and management. At present however, the underlying processes, their simulation and prediction are still not well understood. Due to the urgent need of reliable simulations of the processes, the requirements for a new model were defined. This study, started in 2004 and taking 3 years, is supported by the Joined Doctoral Programme on \u93Risk Management on Built Environment\u94 (Study University of Florence, Italy and Technical University of Braunschweig, Germany)* and by the European Integrated Research Project FLOODsite (2002- 2006). In this report the processes associated with breaching and the present capability of breach modelling are reviewed. A detailed specification of the new model approach is then proposed.Floodsit
- …
