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Sample records for wave overtopping device

  1. Experimental Study of a Multi Level Overtopping Wave Power Device

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Hald, Tue; Frigaard, Peter Bak

    2002-01-01

    Results of experimental investigations of a floating wave energy device called Power Pyramid is presented. The Power Pyramid utilizes reservoirs in multiple levels when capturing wave overtopping and converting it into electrical energy. The effect of capturing the overtopping in multiple levels,......, using 5 levels introduces practical problems, and is most probably not economically feasible. It is concluded that it is reasonable to use 2 levels (maybe 3), which can increase the efficiency by 25-40 % compared to using a single level.......Results of experimental investigations of a floating wave energy device called Power Pyramid is presented. The Power Pyramid utilizes reservoirs in multiple levels when capturing wave overtopping and converting it into electrical energy. The effect of capturing the overtopping in multiple levels......, compared to only one level, has been evaluated experimentally. From the experimental results, and the performed optimizations based on these, it has been found that the efficiency of a wave power device of the overtopping type can be increased by as much as 76 % by using 5 levels instead of 1. However...

  2. Estimation of Overtopping Rates on Slopes in Wave Power Devices and Other Low Crested Structures

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Burcharth, Hans Falk

    2002-01-01

    Motivated by questions raised by developers of wave energy devices based on wave overtopping concepts, model tests have been performed to study overtopping of structures with limited draught, low crest freeboards and slope geometries designed to increase overtopping and thereby also the captured...

  3. Wave Overtopping of Marine Structures

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter

    During the past 50 years tools for predicting wave overtopping of sea defense structures have continuously been refined. However, developers of wave energy converters have raised questions about how to predict the overtopping of structures with layouts significantly different from those of sea...... to a wide range of sea states. Overtopping slope layouts resulting in substantial energy content in the overtopping discharges have been pointed out. The influence of various geometrical parameters, such as slope shape, shape of guiding walls, draft and crest freeboard, on the overtopping discharges has...... been investigated. The effect of using overtopping reservoirs at multiple levels has also been quantified. The emphasis is generally on optimizing the overtopping with respect to maximizing the potential energy in the overtopping water. Based on the experimental data expressions for predicting wave...

  4. Wave Overtopping at Coastal Structures

    DEFF Research Database (Denmark)

    Geeraearts, Jimmy; De Rouck, Julien; Troch, Peter

    2006-01-01

    The European research project CLASH (EVK3-CT-2001-00058) investigated wave overtopping at coastal structures. More specific it was to develop a generic prediction method for wave overtopping and to solve the problem of suspected scale effects. The paper summarizes the main results concerning...

  5. Design, Construction, Reliability and Hydraulic Performance of an Innovative Wave Overtopping Device

    DEFF Research Database (Denmark)

    Frigaard, Peter; Andersen, Thomas Lykke; Margheritini, Lucia

    2008-01-01

    The SSG (Sea Slot-cone Generator) is a wave energy converter of the overtopping type. The structure consists of a number of reservoirs one on the top of each others above the mean water level, in which the water of incoming waves is stored temporary. In each reservoir, expressively designed low h...

  6. Wave Overtopping Characteristics of the Wave Dragon

    DEFF Research Database (Denmark)

    Tedd, James; Kofoed, Jens Peter

    Simulation work has been used extensively with the Wave dragon and other overtopping devices to analyse the power production performance of them and to optimise the structural design and the control strategy. A time domain approach to this is well documented in Jakobsen & Frigaard 1999. Using...... measurements taken from the Wave Dragon Nissum Bredning prototype, some of the previous assumptions have been slightly modified and improved upon, so that the simulation method better represents the reality of what is occurring....

  7. Geometry Optimization of an Overtopping Wave Energy Device Implemented into the New Breakwater of the Hanstholm Port Expansion

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Stratigaki, Vasiliki; Troch, Peter

    2012-01-01

    breakwater is 1.5 km and the water depth ranges approximately from 8.0 m up to 14 m with localized influences on the wave climate. The study is conducted numerically in order to present the expected power production and overall performance of the SSG breakwater in Hanstholm. The price par kWh is also......The study presented here describes the geometry optimization of the Sea wave Slot cone Generator (SSG) overtopping wave energy converter as part of the feasibility study for the implementation of the device in the development plan of Hanstholm harbour in Denmark. The total length of the new planned...

  8. SSG wave energy converter. Design, reliability and hydraulic performance of an innovative overtopping device

    Energy Technology Data Exchange (ETDEWEB)

    Margheritini, L.; Frigaard, P. [Department of Civil Engineering, Aalborg University. Sohngaardsholmsvej 57, DK-9000 Aalborg (Denmark); Vicinanza, D. [Department of Civil Engineering - CIRIAM, Seconda Universita di Napoli. Via Roma 29, 81031 Aversa (Caserta) (Italy)

    2009-05-15

    The SSG (Sea Slot-cone Generator) is a wave energy converter of the overtopping type. The structure consists of a number of reservoirs one on the top of each other above the mean water level in which the water of incoming waves is stored temporary. In each reservoir, expressively designed low head hydro-turbines are converting the potential energy of the stored water into power. A key to success for the SSG will be the low cost of the structure and its robustness. The construction of the pilot plant is scheduled and this paper aims to describe the concept of the SSG wave energy converter and the studies behind the process that leads to its construction. The pilot plant is an on-shore full-scale module in 3 levels with an expected power production of 320 MWh/y in the North Sea. Location, wave climate and laboratory tests' results will be used here to describe the pilot plant and its characteristics. (author)

  9. Experimental Modelling of the Overtopping Flow on the Wave Dragon Wave Energy Converter

    DEFF Research Database (Denmark)

    Parmeggiani, Stefano; Kofoed, Jens Peter

    The Wave Dragon is a floating slack-moored Wave Energy Converter (WEC) of the overtopping type. Oncoming waves are focused by two wing reflectors towards the ramp of the device, surge-up and overtop into a reservoir placed at a higher level than the surface of the sea. The energy production takes...

  10. Landward Distribution of Wave Overtopping for Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.

    2006-01-01

    Overtopping data from seven model test projects has been analyzed with respect to the landward spatial distribution of the overtopping discharge. In total more than 1000 overtopping tests have been analysed and a formula derived for prediction of the landward distribution of overtopping behind...... rubble mound structures with a super structure. The analysis led to the conclusion that although the overtopping discharge, for identical wave heights, decreases with increasing wave steepness, then the maximum travel distance increases with increasing wave steepness....

  11. Measurements of Overtopping Flow Time Series on the Wave Dragon, Wave Energy Converter

    DEFF Research Database (Denmark)

    Tedd, James; Kofoed, Jens Peter

    2009-01-01

    A study of overtopping flow series on the Wave Dragon prototype, a low crested device designed to maximise flow, in a real sea, is presented. This study aims to fill the gap in the literature on time series of flow overtopping low crested structures. By comparing to a simulated flow the character......A study of overtopping flow series on the Wave Dragon prototype, a low crested device designed to maximise flow, in a real sea, is presented. This study aims to fill the gap in the literature on time series of flow overtopping low crested structures. By comparing to a simulated flow...... the characteristics of the overtopping flow are discussed and the simulation algorithm is tested. Measured data is shown from a storm build up in October 2006, from theWave Dragon prototype situated in an inland sea in Northern Denmark. This wave energy converter extracts energy from the waves, by funnelling them...

  12. Experimental Update of the Overtopping Model Used for the Wave Dragon Wave Energy Converter

    DEFF Research Database (Denmark)

    Parmeggiani, Stefano; Kofoed, Jens Peter; Friis-Madsen, Erik

    2013-01-01

    An overtopping model specifically suited for Wave Dragon is needed in order to improve the reliability of its performance estimates. The model shall be comprehensive of all relevant physical processes that affect overtopping and flexible to adapt to any local conditions and device configuration....... An experimental investigation is carried out to update an existing formulation suited for 2D draft-limited, low-crested structures, in order to include the effects on the overtopping flow of the wave steepness, the 3D geometry of Wave Dragon, the wing reflectors, the device motions and the non-rigid connection...... of which can be measured in real-time. Instead of using new fitting coefficients, this approach allows a broader applicability of the model beyond the Wave Dragon case, to any overtopping WEC or structure within the range of tested conditions. Predictions reliability of overtopping over Wave Dragon...

  13. A Critical Analysis and Validation of the Accuracy of Wave Overtopping Prediction Formulae for OWECs

    Directory of Open Access Journals (Sweden)

    David Gallach-Sánchez

    2018-01-01

    Full Text Available The development of wave energy devices is growing in recent years. One type of device is the overtopping wave energy converter (OWEC, for which the knowledge of the wave overtopping rates is a basic and crucial aspect in their design. In particular, the most interesting range to study is for OWECs with steep slopes to vertical walls, and with very small freeboards and zero freeboards where the overtopping rate is maximized, and which can be generalized as steep low-crested structures. Recently, wave overtopping prediction formulae have been published for this type of structures, although their accuracy has not been fully assessed, as the overtopping data available in this range is scarce. We performed a critical analysis of the overtopping prediction formulae for steep low-crested structures and the validation of the accuracy of these formulae, based on new overtopping data for steep low-crested structures obtained at Ghent University. This paper summarizes the existing knowledge about average wave overtopping, describes the physical model tests performed, analyses the results and compares them to existing prediction formulae. The new dataset extends the wave overtopping data towards vertical walls and zero freeboard structures. In general, the new dataset validated the more recent overtopping formulae focused on steep slopes with small freeboards, although the formulae are underpredicting the average overtopping rates for very small and zero relative crest freeboards.

  14. Experimental Overtopping Investigation for the Wave Dragon

    DEFF Research Database (Denmark)

    Borgarino, Bruno; Kofoed, Jens Peter; Tedd, James

    The present report displays the results from overtopping tests carried on the 1:51.8 Wave Dragon model in September 2007. This tests have been carried on by Bruno Borgarino, James Tedd and Jens Peter Kofoed in the wave tank facilities of Aalborg University. The objective was to provide an updated...

  15. Experimental Modeling of the Overtopping Flow on the Wave Dragon Wave Energy Converter

    DEFF Research Database (Denmark)

    Parmeggiani, Stefano; Kofoed, Jens Peter; Friis-Madsen, Erik

    2011-01-01

    The Wave Dragon Wave Energy Converter is currently facing a precommercial phase. At this stage of development a reliable overtopping model is highly required, in order to predict the performance of the device at possible deployment locations. A model formulation derived for an overtopping device...... with general geometry has been used so far. The paper presents an updated formulation drawn through the tank testing of a scaled model the Wave Dragon. The sensitivity analysis of the main features influencing the overtopping flow led to an updated model formulation which can be specifically suited...... for the Wave Dragon....

  16. Hydrodynamic Behavior of Overtopping Wave Energy Converters Built in Sea Defense Structures

    DEFF Research Database (Denmark)

    Victor, Lander; Kofoed, Jens Peter; Troch, Peter

    2010-01-01

    Many sea defense structures need to be adapted to the rising sea water level and changing wave climate due to global warming. The accordingly required investment opens perspectives for wave energy converters (WECs) – that are built as part of the sea defense structures – to become economically...... viable. In this paper the average overtopping discharges q of overtopping wave energy devices built in sea defense structures are studied. Physical model tests with this type of devices have been carried out in a wave flume leading to experimental q - values. The experimental q -values are compared...... with predicted average overtopping discharges by existing empirical formulae from literature. Overtopping converters have low relative crest freeboards and smooth slope characteristics to maximize overtopping, which is contradictive to the basic role of sea defense structures. As a consequence, the achieved...

  17. Wave loadings acting on Overtopping Breakwater for Energy Conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Nørgaard, Jørgen Harck; Contestabile, Pasquale

    2013-01-01

    distributions. Load measurements were compared with the most used prediction method for traditional breakwaters, available in the Coastal Engineering Manual (U.S. Army Corps of Engineers, 2002). These results suggest to use the experimental data as design loadings since the design criteria for the innovative......Any kind of Wave Energy Converter (WEC) requires information on reliability of technology and on time required for the return of the investment (reasonable payback). The structural response is one of the most important parameters to take in to account for a consistent assessment on innovative...... devices. This paper presents results on wave loading acting on an hybrid WEC named Overtopping BReakwater for Energy Conversion (OBREC). The new design is based on the concept of an integration between a traditional rubble mound breakwater and a front reservoir designed to store the wave overtopping from...

  18. Experimental Update of the Overtopping Model Used for the Wave Dragon Wave Energy Converter

    Directory of Open Access Journals (Sweden)

    Erik Friis-Madsen

    2013-04-01

    Full Text Available An overtopping model specifically suited for Wave Dragon is needed in order to improve the reliability of its performance estimates. The model shall be comprehensive of all relevant physical processes that affect overtopping and flexible to adapt to any local conditions and device configuration. An experimental investigation is carried out to update an existing formulation suited for 2D draft-limited, low-crested structures, in order to include the effects on the overtopping flow of the wave steepness, the 3D geometry of Wave Dragon, the wing reflectors, the device motions and the non-rigid connection between platform and reflectors. The study is carried out in four phases, each of them specifically targeted at quantifying one of these effects through a sensitivity analysis and at modeling it through custom-made parameters. These are depending on features of the wave or the device configuration, all of which can be measured in real-time. Instead of using new fitting coefficients, this approach allows a broader applicability of the model beyond the Wave Dragon case, to any overtopping WEC or structure within the range of tested conditions. Predictions reliability of overtopping over Wave Dragon increased, as the updated model allows improved accuracy and precision respect to the former version.

  19. COMPARISON OF NUMERICAL AND EXPERIMENTAL RESULTS FOR OVERTOPPING DISCHARGE OF THE OBREC WAVE ENERGY CONVERTER

    Directory of Open Access Journals (Sweden)

    A. YAZID MALIKI

    2017-05-01

    Full Text Available OBREC is the latest innovation of overtopping wave energy converter (WEC which is coalesced with the rubble mound breakwaters. The acquisition of wave overtopping in a front reservoir and consequently releasing process through turbine is the concept of energy production in OBREC. The physical scale model studies of overtopping discharge of the OBREC have recently been done by previous researcher in wave flume at Aalborg University. This paper demonstrates the overtopping behavior of OBREC device using a VOF method with capabilities to solve RANS equation in the numerical suite Flow3D. The purpose of this research is to validate the overtopping discharge performance of the numerical model against the experiments of the OBREC. Based on the observation, the results have shown a good agreement between the validation and physical experiment.

  20. Role of beach morphology in wave overtopping hazard assessment

    Science.gov (United States)

    Phillips, Benjamin; Brown, Jennifer; Bidlot, Jean-Raymond; Plater, Andrew

    2017-04-01

    Understanding the role of beach morphology in controlling wave overtopping volume will further minimise uncertainties in flood risk assessments at coastal locations defended by engineered structures worldwide. XBeach is used to model wave overtopping volume for a 1:200 yr joint probability distribution of waves and water levels with measured, pre- and post-storm beach profiles. The simulation with measured bathymetry is repeated with and without morphological evolution enabled during the modelled storm event. This research assesses the role of morphology in controlling wave overtopping volumes for hazardous events that meet the typical design level of coastal defence structures. Results show disabling storm-driven morphology under-represents modelled wave overtopping volumes by up to 39% under high Hs conditions, and has a greater impact on the wave overtopping rate than the variability applied within the boundary conditions due to the range of wave-water level combinations that meet the 1:200 yr joint probability criterion. Accounting for morphology in flood modelling is therefore critical for accurately predicting wave overtopping volumes and the resulting flood hazard and to assess economic losses.

  1. Overtopping Measurements on the Wave Dragon Nissum Bredning Prototype

    DEFF Research Database (Denmark)

    Frigaard, Peter; Kofoed, Jens Peter; Rasmussen, Michael R.

    2004-01-01

    The paper describes the methods used to estimate (calculated from some indirect measurements) the overtopping of the wave energy converter Wave Dragon placed in a real sea environment. The wave energy converter in quistion is the 237-tonne heavy Wave Dragon Nissum Bredning Prototype. Comparisons...

  2. Optimization of Overtopping Wave Energy Converters by Geometry Control

    DEFF Research Database (Denmark)

    Victor, L.; Troch, P.; Kofoed, Jens Peter

    2011-01-01

    In this paper, the results of a study on the effects of geometry control on the performance of overtopping wave energy converters with a simple geometry built in coastal structures (simple OWECs) are presented. Empirical formulae, derived based on experimental tests on simple OWECs with varying...

  3. Wave overtopping erosion tests at Groningen sea dyke

    NARCIS (Netherlands)

    Verhagen, H.J.; Akkerman, G.J.; van Gerven, K.A.J.; Schaap, H.A.; van der Meer, J.W.

    2007-01-01

    In the present report field erosion tests of the inner slope of a sea dyke in the province of Groningen (near Delfzijl) are described for the situation of severe wave overtopping. Three types of tests have been performed: tests at the present grass cover, tests at a reinforced grass cover and tests

  4. Hydraulic Performance of an Innovative Breakwater for Overtopping Wave Energy Conversion

    Directory of Open Access Journals (Sweden)

    Claudio Iuppa

    2016-11-01

    Full Text Available The Overtopping BReakwaterfor Energy Conversion (OBREC is an overtopping wave energy converter, totally embedded in traditional rubble mound breakwaters. The device consists of a reinforced concrete front reservoir designed with the aim of capturing the wave overtopping in order to produce electricity. The energy is extracted through low head turbines, using the difference between the water levels in the reservoir and the sea water level. This paper analyzes the OBREC hydraulic performances based on physical 2D model tests carried out at Aalborg University (DK. The analysis of the results has led to an improvement in the overall knowledge of the device behavior, completing the main observations from the complementary tests campaign carried out in 2012 in the same wave flume. New prediction formula are presented for wave reflection, the overtopping rate inside the front reservoir and at the rear side of the structure. Such methods have been used to design the first OBREC prototype breakwater in operation since January 2016 at Naples Harbor (Italy.

  5. Turbine Control Strategy using Wave Prediction to Optimise Power Take Off of Overtopping Wave Energy Converters

    DEFF Research Database (Denmark)

    Tedd, James; Knapp, Wilfried; Frigaard, Peter

    2005-01-01

    This paper presents the control strategy used on Wave Dragon overtopping wave energy converter. The nature of overtopping requires that for optimum performance the water level in the reservoir must be controlled by controlling the turbine outflows. A history of the simulations performed is included...

  6. 3D Tests on Overtopping for SSG Wave Energy Converter

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Kofoed, Jens Peter

    This report presents the results of the first study based on laboratory tests of the behaviour of the SSG pilot module in 3D wave conditions. This study was recommended already during Phase 2 of the Co-operation agreement between WEVEnergy AS (Norway) and Aalborg University, Department of Civil...... of the individual reservoirs have been measured and the hydraulic efficiency calculated. The results are given in terms of overtopping rates for the 3 reservoirs and hydraulic efficiency....

  7. Turbine Control Strategy using Wave Prediction to Optimise Power Take Off of Overtopping Wave Energy Converters

    OpenAIRE

    Tedd, James; Knapp, Wilfried; Frigaard, Peter; Kofoed, Jens Peter

    2005-01-01

    This paper presents the control strategy used on Wave Dragon overtopping wave energy converter. The nature of overtopping requires that for optimum performance the water level in the reservoir must be controlled by controlling the turbine outflows. A history of the simulations performed is included. The concept of including an element of prediction, based on wave records a short distance in front of the Wave Dragon, is introduced. Initial simulations indicate a possibility to increase product...

  8. Innovative rubble mound breakwaters for overtopping wave energy conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Contestabile, Pasquale; Nørgaard, Jørgen Quvang Harck

    2014-01-01

    to the sea through turbines. Wave loadings and average wave overtopping rate at the rear side of the rubble mound breakwater and in the front reservoir are discussed on the basis of physical 2-D model tests carried out at Aalborg University (DK). The experiments have been analyzed and compared with results...... from model tests and wave load design formulae by Nørgaard et al. (2013) for traditional rubble mound crown walls. The existing prediction methods seem unable to predict the hydraulic performances and loadings on the front reservoir and thus new prediction formulae are proposed based on the new...

  9. Simulation of Wave Overtopping of Maritime Structures in a Numerical Wave Flume

    Directory of Open Access Journals (Sweden)

    Tiago C. A. Oliveira

    2012-01-01

    Full Text Available A numerical wave flume based on the particle finite element method (PFEM is applied to simulate wave overtopping for impermeable maritime structures. An assessment of the performance and robustness of the numerical wave flume is carried out for two different cases comparing numerical results with experimental data. In the first case, a well-defined benchmark test of a simple low-crested structure overtopped by regular nonbreaking waves is presented, tested in the lab, and simulated in the numerical wave flume. In the second case, state-of-the-art physical experiments of a trapezoidal structure placed on a sloping beach overtopped by regular breaking waves are simulated in the numerical wave flume. For both cases, main overtopping events are well detected by the numerical wave flume. However, nonlinear processes controlling the tests proposed, such as nonlinear wave generation, energy losses along the wave propagation track, wave reflection, and overtopping events, are reproduced with more accuracy in the first case. Results indicate that a numerical wave flume based on the PFEM can be applied as an efficient tool to supplement physical models, semiempirical formulations, and other numerical techniques to deal with overtopping of maritime structures.

  10. Wave Overtopping of a Barrier Beach

    Science.gov (United States)

    2009-09-01

    but can result in increased dune erosion along Scenic Road as occurred in 1993, 1997, and 2005 (James, 2005). Field data and observations for...factors are equal to 1. The equations for these run-up formulas are parameterized on significant wave height at the toe of the structure as measured in...3 exp C r SS RQ C D HgH γ ⎛ ⎞ = −⎜ ⎟ ⎝ ⎠ 2pξ > where the significant wave height at the toe of the structure, SH and pT are used. Again the

  11. Modelling of the Overtopping Flow on the Wave Dragon Wave Energy Converter

    DEFF Research Database (Denmark)

    Parmeggiani, Stefano; Pecher, Arthur; Kofoed, Jens Peter

    2010-01-01

    The Wave Dragon is a floating slack-moored Wave Energy Converter of the overtopping type, which is facing now the last phase of development before the commercial exploitation: the deployment of a full-scale demonstrator. In this phase a modelling tool allowing for accurate predictions of the perf......The Wave Dragon is a floating slack-moored Wave Energy Converter of the overtopping type, which is facing now the last phase of development before the commercial exploitation: the deployment of a full-scale demonstrator. In this phase a modelling tool allowing for accurate predictions...

  12. Wave loadings acting on innovative rubble mound breakwater for overtopping wave energy conversion

    DEFF Research Database (Denmark)

    Contestabile, Pasquale; Iuppa, Claudio; Lauro, Enrico Di

    2017-01-01

    Highlights •An innovative breakwater for overtopping wave energy conversion has been studied. •Physical model tests have been carried out and analysed. •Breakwater design information on loadings acting on various parts of the structure has been presented. •Design formulae and validation of some t...

  13. Model Study of Wave Overtopping of Marine Structure for a Wide Range of Geometric Parameters

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter

    2000-01-01

    The objective of the study described in this paper is to enable estimation of wave overtopping rates for slopes/ramps given by a wide range of geometric parameters when subjected to varying wave conditions. To achieve this a great number of model tests are carried out in a wave tank using irregul...... 2-D waves. On the basis of the first part of these tests an exponential overtopping expression for a linear slope, including the effect of limited draught and varying slope angle, is presented. The plans for further tests with other slope geometries are described....

  14. Analysis of Overtopping Flow on Sea Dikes in Oblique and Short-Crested Waves

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Thomas Lykke; Burcharth, Hans F.

    2013-01-01

    -empirical formulae for the estimation of flow depths and flow velocities across a dike. The results have been coupled to the actual erosion of the landward dike slope determined by full-scale 2D tests using the so-called “Overtopping Simulator”. This paper describes the results from 96 small-scale tests carried out...... directions on the dike, and the statistical distribution of individual flow parameters are needed to obtain more realistic estimates of dike erosion caused by wave overtopping....

  15. Crest Level Optimization of the Multi Level Overtopping based Wave Energy Converter Seawave Slot-Cone Generator

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Osaland, E.

    2005-01-01

    The paper describes the optimization of the crest levels and geometrical layout of the SSG structure, focusing on maximizing the obtained potential energy in the overtopping water. During wave tank testing at AAU average overtopping rates into the individual reservoirs have been measured. The ini......The paper describes the optimization of the crest levels and geometrical layout of the SSG structure, focusing on maximizing the obtained potential energy in the overtopping water. During wave tank testing at AAU average overtopping rates into the individual reservoirs have been measured....... The initial tests led to an expression describing the derivative of the overtopping rate with respect to the vertical distance. Based on this, numerical optimizations of the crest levels, for a number of combinations of wave conditions, have been performed. The hereby found optimal crest levels have been...

  16. On the Effects of Geometry Control on the Performance of Overtopping Wave Energy Converters

    DEFF Research Database (Denmark)

    Victor, Lander; Troch, Peter; Kofoed, Jens Peter

    2011-01-01

    Overtopping wave energy converters (OWECs) are designed to extract energy from ocean waves based on wave overtopping into a reservoir, which is emptied into the ocean through a set of low-head turbines, and typically feature a low crest freeboard and a smooth impermeable steep slope. In the process...... of optimizing the performance of OWECs, the question arises whether adapting the slope geometry to the variable wave characteristics at the deployment site (i.e., geometry control) can increase the overall hydraulic efficiency and overall hydraulic power compared to a fixed slope geometry. The effect of five...... different geometry control scenarios on the overall hydraulic efficiency and overall hydraulic power of OWECs has been simulated for three possible deployment sites using empirical prediction formulae. The results show that the effect of an adaptive slope angle is relatively small. On the other hand...

  17. Effects of vertical wall and tetrapod weights on wave overtopping in rubble mound breakwaters under irregular wave conditions

    Directory of Open Access Journals (Sweden)

    Park Sang Kil

    2014-12-01

    Full Text Available Rubble mound breakwaters protect the coastal line against severe erosion caused by wave action. This study examined the performance of different sizes and properties (i.e. height of vertical wall and tetrapod size of rubble mound breakwaters on reducing the overtopping discharge. The physical model used in this study was derived based on an actual rubble mound in Busan Yacht Harbor. This research attempts to fill the gap in practical knowledge on the combined effect of the armor roughness and vertical wall on wave overtopping in rubble mound breakwaters. The main governing parameters used in this study were the vertical wall height, variation of the tetrapod weights, initial water level elevation, and the volume of overtopping under constant wave properties. The experimental results showed that the roughness factor differed according to the tetrapod size. Furthermore, the overtopping discharge with no vertical wall was similar to that with relatively short vertical walls ( 1 γv = 1. Therefore, the experimental results highlight the importance of the height of the vertical wall in reducing overtopping discharge. Moreover, a large tetrapod size may allow coastal engineers to choose a shorter vertical wall to save cost, while obtaining better performance.

  18. Effects of vertical wall and tetrapod weights on wave overtopping in rubble mound breakwaters under irregular wave conditions

    Directory of Open Access Journals (Sweden)

    Sang Kil Park

    2014-12-01

    Full Text Available Rubble mound breakwaters protect the coastal line against severe erosion caused by wave action. This study examined the performance of different sizes and properties (i.e. height of vertical wall and tetrapod size of rubble mound breakwaters on reducing the overtopping discharge. The physical model used in this study was derived based on an actual rubble mound in Busan Yacht Harbor. This research attempts to fill the gap in practical knowledge on the combined effect of the armor roughness and vertical wall on wave overtopping in rubble mound breakwaters. The main governing parameters used in this study were the vertical wall height, variation of the tetrapod weights, initial water level elevation, and the volume of overtopping under constant wave properties. The experimental results showed that the roughness factor differed according to the tetrapod size. Furthermore, the overtopping discharge with no vertical wall was similar to that with relatively short vertical walls (γν = 1. Therefore, the experimental results highlight the importance of the height of the vertical wall in reducing overtopping discharge. Moreover, a large tetrapod size may allow coastal engineers to choose a shorter vertical wall to save cost, while obtaining better performance.

  19. Prediction of the Individual Wave Overtopping Volumes of a Wave Energy Converter using Experimental Testing and First Numerical Model Results

    DEFF Research Database (Denmark)

    Victor, L.; Troch, P.; Kofoed, Jens Peter

    2009-01-01

    For overtopping wave energy converters (WECs) a more efficient energy conversion can be achieved when the volumes of water, wave by wave, that enter their reservoir are known and can be predicted. A numerical tool is being developed using a commercial CFD-solver to study and optimize...... nearshore 2Dstructure. First numerical model results are given for a specific test with regular waves, and are compared with the corresponding experimental results in this paper....

  20. Wave Overtopping over Crown Walls and Run-up on Rubble Mound Breakwaters with Kolos Armour under Random Waves

    Directory of Open Access Journals (Sweden)

    A. Arunjith

    2013-06-01

    Full Text Available The design of rubble mound structures like breakwaters and seawalls are influenced by the wave run-up and overtopping over them. The above phenomena largely depend on the type of the armour units as they directly interact with the incident waves. The hydrodynamic characteristics of various concrete armour units have been established by several researchers. A new armour block, ‘Kolos’, a modified version of Dolos, is considered in this study for a detailed investigation. An attempt is made to establish empirical relationships for the estimation of wave overtopping discharges over crown wall and run-up on Kolosarmoured slope exposed to random wave from the results of a comprehensive experimental program. Further, the results are compared with that of a tested section with natural rocks as armour layer and with that of other investigators.

  1. Wave Overtopping over Crown Walls and Run-up on Rubble Mound Breakwaters with Kolos Armour under Random Waves

    OpenAIRE

    A. Arunjith; S.A. Sannasiraj; V. Sundar

    2013-01-01

    The design of rubble mound structures like breakwaters and seawalls are influenced by the wave run-up and overtopping over them. The above phenomena largely depend on the type of the armour units as they directly interact with the incident waves. The hydrodynamic characteristics of various concrete armour units have been established by several researchers. A new armour block, ‘Kolos’, a modified version of Dolos, is considered in this study for a detailed investigation. An attempt is made to ...

  2. Sea Slot Cone Generator Overtopping Performance in 3D Conditions

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Vicinanza, Diego; Frigaard, Peter

    2008-01-01

    This note describes the influence of wave spreading, directionality and local bathymetry on the efficiency of the SSG wave energy converter Pilot plant in Kvitsøy, Norway. This is an overtopping device i.e. its efficiency is directly proportional to the overtopping flows in the three reservoirs t...... is also described. It has been found that the performance of the SSG Pilot will be negatively affected by spreading and directionality of the incoming waves as direct consequence of reduction on the overtopping flow rates of 10% - 35% compared to 2D conditions....

  3. Marine Structures with Heavy Overtopping

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter

    2000-01-01

    An investigation of wave overtopping of marine structures is described. Focus is put on structures with realtively low crest levels and various slope layouts subjected to non-breaking waves. Influence of slope draught and angle is investigated....

  4. CFD study of the overtopping discharge of the Wave Dragon wave energy converter

    DEFF Research Database (Denmark)

    Eskilsson, K.; Palm, J.; Kofoed, Jens Peter

    2015-01-01

    incompressible Euler/Navier-Stokes solver in the OpenFOAM® framework. We present simulations of: (i) a complete sea state for different crest heights, and (ii) regular waves for different wave conditions and crest heights. The simulations compare reasonably well with the experimental data, albeit the irregular...

  5. R&D Towards Commercialization of Sea Wave Slot Cone Generator (SSG) Overtopping Wave Energy Converter

    DEFF Research Database (Denmark)

    Margheritini, Lucia

    between ventures and private investors, and to promote an accelerated shift from a technology to a market focus. This Thesis is presented as a collection of works published by the author on her research on the Sea wave Slot cone Generator wave energy converter. These include 1 accepted and 2 submitted......Global energy needs are likely to continue to grow steadily for the next two and a half decades (International Energy Agency, 2006). If governments continue with current policies the world’s energy needs would be more than 50% higher in 2030 than today. Over 60% of that increase would be covered...... in the form of oil and natural gas. Climate destabilizing carbon-dioxide emissions would continue to rise, calling into question the long-term sustainability of the global energy system. More vigorous government policies in consuming countries are steering the world onto an energy path oriented to reduce...

  6. Surface stability analysis of dikes subject to overtopping and infiltration

    NARCIS (Netherlands)

    Karim, U. F.A.; Tran, Q.T.; Meij, R.

    2015-01-01

    The key contribution of this paper is the coupling of hydraulic loading conditions due to wave overtopping with slope stability of the surface layer of earthen flood protection embankments. Overtopping wave conditions impact overtopping discharges and infiltration time, and thereby the infiltration

  7. Conceptual Design of Wave Plane

    DEFF Research Database (Denmark)

    Frigaard, Peter; Trewers, Andrew; Kofoed, Jens Peter

    The Wave Plane is a patented Wave Energy device of the overtopping type, designed to capture potential as well as kinetic energy. This is as such different to other overtopping devices, who usually only focus on potential energy. If Wave Plane A/S can deliver the turbine technology to utilize both...

  8. Marine Structures with Extreme Overtopping Rates

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter

    2000-01-01

    In design of sea defence structures like seawalls, breakwaters and dikes, one of the main objectives is to minimize or even eliminate wave overtopping. For this reason numerous investigations have been performed over the past many years to determine the amount of overtopping occurring for typical...

  9. A SYSTEM TO MAKE USE OF EXISTING BREAKWATERS AS OVERTOPPING WAVE ENERGY CONVERTERS

    Directory of Open Access Journals (Sweden)

    DENIZ ÜNSALAN

    2016-06-01

    Full Text Available The main purpose of building breakwaters is to produce safe havens for ships and boats in rough seas. The general architecture for a breakwater is a wall with a trapezoidal -shaped cross section extending parallel to the shoreline. As the waves from the open sea approach, they are encountered by the so- called slope and revetment of the breakwater, where the wave is broken and its energy is dissipated and/or reflected back. However, the ever -increasing attractiveness of the utilization of waves as energy sources, paralleling to the increasing monetary and envir onmental costs of energy, has led the authors to consider the vast amounts of this otherwise dissipated energy into useful electrical energy. A wave energy conversion concept, which can be classified as an “overtopping” wave energy converter was conceived, where the open sea-facing (revetment side of the breakwater is fitted by a water collecting channel at a suitable height above the calm water level, running alongside the breakwater. The channel leads the collected water to a powerhouse containing a low head turbine (or a set of such turbines discharging it to the calm water of the inner harbour. Power obtained from these turbines can be converted to electrical energy. In this study, an estimation of the volume of water collected by the channel and the energy production for a proposed breakwater - power station system for a typical rough weather shall be made. It is deemed that the feasibility of this system is comparable to and even higher than the other wave energy conversion systems since it does not require additional facilities and power supply lines to be built due to its proximity to the existing energy transmission lines, except for the addition of new features/installations to the existing breakwaters.

  10. Wave Loading and Overtopping on Vertical Wall Breakwaters in Multidirectional Breaking Seas

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Grønbech, J.; Hald, Tue

    1998-01-01

    The present paper concerns the results and findings of a physical study on wave impacts on vertical caisson breakwaters situated in irregular, multidirectional breaking seas. The study has taken place as part of the framework programme "Dynamics of Structures" financially supported by the Danish...

  11. Wave Loading and Overtopping on Caisson Breakwaters in Multidirectional Breaking Seas

    DEFF Research Database (Denmark)

    Grønbech, J.; Hald, Tue; Frigaard, Peter

    1997-01-01

    The present paper concerns the results and findings of a physical study on wave impacts on vertical caisson breakwaters situated in irregular, multidirectional breaking seas. The study has taken place as a part of the framework programme "Dynamics of Structures" financially supported by the Danish...

  12. Failure of Grass Covered Flood Defences with Roads on Top Due to Wave Overtopping: A Probabilistic Assessment Method

    Directory of Open Access Journals (Sweden)

    Juan P. Aguilar-López

    2018-06-01

    Full Text Available Hard structures, i.e., roads, are commonly found over flood defences, such as dikes, in order to ensure access and connectivity between flood protected areas. Several climate change future scenario studies have concluded that flood defences will be required to withstand more severe storms than the ones used for their original design. Therefore, this paper presents a probabilistic methodology to assess the effect of a road on top of a dike: it gives the failure probability of the grass cover due to wave overtopping over a wide range of design storms. The methodology was developed by building two different dike configurations in computational fluid dynamics Navier–Stokes solution software; one with a road on top and one without a road. Both models were validated with experimental data collected from field-scale experiments. Later, both models were used to produce data sets for training simpler and faster emulators. These emulators were coupled to a simplified erosion model which allowed testing storm scenarios which resulted in local scouring conditioned statistical failure probabilities. From these results it was estimated that the dike with a road has higher probabilities (5 × 10−5 > Pf >1 × 10−4 of failure than a dike without a road (Pf < 1 × 10−6 if realistic grass quality spatial distributions were assumed. The coupled emulator-erosion model was able to yield realistic probabilities, given all the uncertainties in the modelling process and it seems to be a promising tool for quantifying grass cover erosion failure.

  13. Electromagnetic wave matching device

    International Nuclear Information System (INIS)

    Hirata, Yosuke; Mitsunaka, Yoshika; Hayashi, Ken-ichi; Ito, Yasuyuki.

    1997-01-01

    The present invention provides a matching device capable of increasing an efficiency of combining beams of electromagnetic waves outputted from an output window of a gyrotron which is expected for plasma heating of a thermonuclear reactor and an electromagnetic wave transmission system as high as possible. Namely, an electromagnetic wave matching device reflects beams of electromagnetic waves incident from an inlet by a plurality of phase correction mirrors and combines them to an external transmission system through an exit. In this case, the phase correction mirrors change the phase of the beams of electromagnetic waves incident to the phase correction mirrors by a predetermined amount corresponding to the position of the reflection mirrors. Then, the beams of electromagnetic waves outputted, for example, from a gyrotron can properly be shaped as desired for the intensity and the phase. As a result, combination efficiency with the transmission system can be increased. (I.S.)

  14. Individual Violent Overtopping Events: New Insights

    DEFF Research Database (Denmark)

    Jayaratne, R.; Hunt-Raby, A.; Bullock, G. N.

    2009-01-01

    Wave overtopping is essentially a discrete process in which disastrous consequences can arise from the effect of one or two waves; few of the thousands of previous experiments have focused on the properties of individual events. The violent impacts of water waves on walls create velocities and pr...

  15. Comparison Between Overtopping Discharge in Small and Large Scale Models

    DEFF Research Database (Denmark)

    Helgason, Einar; Burcharth, Hans F.

    2006-01-01

    The present paper presents overtopping measurements from small scale model test performed at the Haudraulic & Coastal Engineering Laboratory, Aalborg University, Denmark and large scale model tests performed at the Largde Wave Channel,Hannover, Germany. Comparison between results obtained from...... small and large scale model tests show no clear evidence of scale effects for overtopping above a threshold value. In the large scale model no overtopping was measured for waveheights below Hs = 0.5m as the water sunk into the voids between the stones on the crest. For low overtopping scale effects...

  16. Surface Acoustic Wave Devices

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard

    The work of this project is concerned with the simulation of surface acoustic waves (SAW) and topology optimization of SAW devices. SAWs are elastic vibrations that propagate along a material surface and are extensively used in electromechanical filters and resonators in telecommunication. A new...

  17. Seawall Overtopping Tests

    DEFF Research Database (Denmark)

    Frigaard, Peter

    At the request of Mr. J. Bulow Beck, Havnecon A/S the Hydraulics Laboratory at University of Aalborg, Denmark carried out model test with the objective of studying the overtopping of a seawall designed for the protection of a new road and promenade, the SOHAR CORNICE, in the Sultanate of Oman...

  18. Electromagnetic wave matching device

    International Nuclear Information System (INIS)

    Hirata, Yosuke; Mitsunaka, Yoshika; Hayashi, Ken-ichi; Ito, Yasuyuki.

    1997-01-01

    The present invention provides an electromagnetic wave matching capable of reducing a cost for the transmission system in a system of using electromagnetic waves for plasma heating of a thermonuclear reactor. Namely, incident electromagnetic waves are reflected by using a plurality of phase correction mirrors. The reflected electromagnetic waves are connected to an external transmission system through an exit. The phase correction mirrors have such a shape to receive a plurality of beam-like electromagnetic waves and output electromagnetic waves by the number different from the number of the received electromagnetic wave beams having a predetermined distribution. Further, at least two of the phase correction mirrors have such a shape to change the phase of the electromagnetic waves beams incident to the reflection surface of the phase correction mirrors by a predetermined amount corresponding to the position of the reflection surface. Then, the cost for transmission system can greatly be reduced. (I.S.)

  19. Risk analysis for earth dam overtopping

    Directory of Open Access Journals (Sweden)

    Mo Chongxun

    2008-06-01

    Full Text Available In this paper, a model of overtopping risk under the joint effects of floods and wind waves, which is based on risk analysis theory and takes into account the uncertainties of floods, wind waves, reservoir capacity and discharge capacity of the spillway, is proposed and applied to the Chengbihe Reservoir in Baise City in Guangxi Zhuang Autonomous Region. The simulated results indicate that the flood control limiting level can be raised by 0.40 m under the condition that the reservoir overtopping risk is controlled within a mean variance of 5×10−6. As a result, the reservoir storage will increase to 16 million m3 and electrical energy generation and other functions of the reservoir will also increase greatly.

  20. Wave Dragon MW

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter

    Wave Dragon is a wave energy converter of the overtopping type. The device has been thoroughly tested on a 1:51.8 scale model in wave laboratories and a 1:4.5 scale model deployed in Nissum Bredning, a large inland waterway in Denmark. Based on the experience gained a full scale, multi MW prototype...

  1. Overtopping and Rear Slope Stability of Reshaping & Non-reshaping Berm Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, H. F.

    2004-01-01

    Overtopping and rear slope stability of reshaping and non-reshaping berm breakwaters have been studied in a wave flume. A total of 695 tests have been performed to cover the influence of crest freeboard, crest width, berm width, berm elevation, stone size and sea state. Formula for average...... overtopping discharge that includes these parameters has been derived. The measurements show good correlation between average overtopping discharge and rear slope damage....

  2. The Wave Energy Device

    DEFF Research Database (Denmark)

    Frigaard, Peter; Kofoed, Jens Peter; Tedd, James William

    2006-01-01

    's first offshore wave energy converter. During this period an extensive measuring program has established the background for optimal design of the structure and regulation of the power take off system. Planning for full scale deployment of a 7 MW unit within the next 2 years is in progress. The prototype...

  3. Wave Transformation over a Fringing Coral Reef and the Importance of Low-Frequency Waves and Offshore Water Levels to Runup and Island Overtopping

    Science.gov (United States)

    Cheriton, O. M.; Storlazzi, C. D.; Rosenberger, K. J.

    2016-02-01

    Low-lying, reef-fringed islands are susceptible to sea-level rise and often subjected to overwash and flooding during large wave events. To quantify wave dynamics and wave-driven water levels on fringing coral reefs, wave gauges and a current meter were deployed for 5 months across two shore-normal transects on Roi-Namur, an atoll island in the Republic of the Marshall Islands. These observations captured two large wave events that had maximum wave heights greater than 6 m and peak periods of 16 s over the fore reef. The larger event coincided with a peak spring tide, leading to energetic, highly-skewed infragravity (0.04-0.004 Hz) and very low frequency (0.004-0.001 Hz) waves at the shoreline, which reached heights of 1.0 and 0.7 m, respectively. Water surface elevations, combined with wave runup, exceeded 3.7 m at the innermost reef flat adjacent to the toe of the beach, resulting in flooding of inland areas. This overwash occurred during a 3-hr time window that coincided with high tide and maximum low-frequency reef flat wave heights. The relatively low-relief characteristics of this narrow reef flat may further drive shoreline amplification of low-frequency waves due to resonance modes. These results demonstrate how the coupling of high offshore water levels with low-frequency reef flat wave energetics can lead to large impacts along atoll and fringing reef-lined shorelines, such as island overwash. These observations lend support to the hypothesis that predicted higher sea levels will lead to more frequent occurrences of both extreme shoreline runup and island overwash, threatening the sustainability of these islands.

  4. Overtopping of Berm Breakwaters Extension of Overtopping Formula

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, H. F.

    2005-01-01

    the formula is improved so it gives reliable estimates also for more stable structures. The extension of the overtopping formula is based on analysis of front slope stability data from many different data sets. In most cases there is only a small difference between the Lykke Andersen & Burcharth (2004......In this paper is presented an improved version of the overtopping formula by Lykke Andersen & Burcharth (2004)valid for berm breakwaters with initial slopes of 1:1.25. In the present paper guidelines is given on how to modify the formula to take into account the initial slope angle. Further...

  5. Experimental investigation of rubble mound breakwaters for wave energy conversion

    DEFF Research Database (Denmark)

    Luppa, C.; Contestabile, P.; Cavallaro, L.

    2015-01-01

    The paper describes recent laboratory investigation on the breakwater integrated device named “OBREC” (Overtopping BReakwater for Energy Conversion). This technology recently appeared on the wave energy converter scene as an executive outcome of improving composite seawalls by including overtoppi......-by-wave measurement of couples of hydraulic head-flow rate acting on a virtual turbine inlet. Finally, the influence of draft length on overtopping discharge has been identified....... type wave energy converters [1]. Two complementary experimental campaigns were carried out, in 2012 and in 2014. Several geometries and wave conditions were examined. Preliminary comparison of hydraulic behaviour has been summarized, focusing on reflection analysis and overtopping flow rate....... Preliminary design formulae are presented to predict overtopping at the rear side of the structure and in to the front reservoir based on both datasets. Moreover, some important results have been presented on hydraulic behaviour of OBREC with saturated reservoir. Particularly attention is paid to wave...

  6. Wave Dragon

    DEFF Research Database (Denmark)

    Tedd, James; Kofoed, Jens Peter; Knapp, W.

    2006-01-01

    Wave Dragon is a floating wave energy converter working by extracting energy principally by means of overtopping of waves into a reservoir. A 1:4.5 scale prototype has been sea tested for 20 months. This paper presents results from testing, experiences gained and developments made during this ext......Wave Dragon is a floating wave energy converter working by extracting energy principally by means of overtopping of waves into a reservoir. A 1:4.5 scale prototype has been sea tested for 20 months. This paper presents results from testing, experiences gained and developments made during...... this extended period. The prototype is highly instrumented. The overtopping characteristic and the power produced are presented here. This has enabled comparison between the prototype and earlier results from both laboratory model and computer simulation. This gives the optimal operating point and the expected...... power of the device. The project development team has gained much soft experience from working in the harsh offshore environment. In particular the effect of marine growth in the draft tubes of the turbines has been investigated. The control of the device has been a focus for development as is operates...

  7. Wave Loadings Acting on an Innovative Breakwater for Energy Production

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Ciardulli, F.; Buccino, M.

    2011-01-01

    The paper reports on 2D small scale experiments conducted to investigate wave loadings acting on a pilot project of device for the conversion of wave energy into electricity. The conversion concept is based on the overtopping principle and the structure is worldwide known with the acronym SSG....... The hydraulic model tests have been carried out at the LInC laboratory of the University of Naples Federico II using random waves. Results indicate wave overtopping is able to cause a sudden inversion of vertical force under wave crest, so that it is alternatively upward and downward directed over a short time...

  8. Modeling the Buoyancy System of a Wave Energy Power Plant

    DEFF Research Database (Denmark)

    Pedersen, Tom S.; Nielsen, Kirsten M.

    2009-01-01

    A nonlinear dynamic model of the buoyancy system in a wave energy power plant is presented. The plant ("Wave Dragon") is a floating device using the potential energy in overtopping waves to produce power. A water reservoir is placed on top of the WD, and hydro turbines lead the water to the sea...... producing electrical power. Through air chambers it is possible to control the level of the WD. It is important to control the level in order to maximize the power production in proportion to the wave height, here the amount of overtopping water and the amount of potential energy is conflicting...

  9. The Crest Wing Wave Energy Device

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Antonishen, Michael Patrick

    to generate power. Model tests have been performed using scale models (length scale 1:30), provided by WaveEnergyFyn, in regular and irregular wave states that can be found in Assessment of Wave Energy Devices. Best Practice as used in Denmark (Frigaard et al., 2008). The tests were carried out at Dept....... of Civil Engineering, Aalborg University (AAU) in the 3D deep water wave tank. The displacement and force applied to a power take off system, provided by WaveEnergyFyn, were measured and used to calculate mechanical power available to the power take off....

  10. Modelling and Testing of Wave Dragon Wave Energy Converter Towards Full Scale Deployment

    DEFF Research Database (Denmark)

    Parmeggiani, Stefano

    -commercial stage in which it has proven difficult to secure the necessary funding for the deployment of a full-scale demonstrator unit. The work presented aims at easing this process, by increasing public and scientific knowledge of the device, as well as by showing the latest progress in its development. Research....... This is mainly due to the development of an updated overtopping model specifically suited to Wave Dragon, which allows greater quality to predictions of the primary energy absorption of the device compared to previous versions. At the same time an equitable approach has been described and used in the performance......, the research has also provided a deeper insight into the physics of the overtopping process by individually assessing the influence of related device configuration and wave features, which goes beyond the present application and may be used for other overtopping WECs as well. Comprehensive analysis...

  11. Wave Pressures and Loads on a Small Scale Model of the Svåheia SSG Pilot Project

    DEFF Research Database (Denmark)

    Buccino, Mariano; Vicinanza, Diego; Ciardulli, Francesco

    2011-01-01

    The paper reports on 2D small scale experiments conducted to investigate wave loadings acting on a pilot project of device for the conversion of wave energy into electricity. The conversion concept is based on the overtopping principle and the structure is worldwide known with the acronym SSG....... The hydraulic model tests have been carried out at the LInC laboratory of the University of Naples Federico II using random waves. Results indicate wave overtopping is able to cause a sudden inversion of vertical force under wave crest, so that it is alternatively upward and downward directed over a short time...

  12. Probabilistic Design of Wave Energy Devices

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Kofoed, Jens Peter; Ferreira, C.B.

    2011-01-01

    Wave energy has a large potential for contributing significantly to production of renewable energy. However, the wave energy sector is still not able to deliver cost competitive and reliable solutions. But the sector has already demonstrated several proofs of concepts. The design of wave energy...... devices is a new and expanding technical area where there is no tradition for probabilistic design—in fact very little full scale devices has been build to date, so it can be said that no design tradition really exists in this area. For this reason it is considered to be of great importance to develop...... and advocate for a probabilistic design approach, as it is assumed (in other areas this has been demonstrated) that this leads to more economical designs compared to designs based on deterministic methods. In the present paper a general framework for probabilistic design and reliability analysis of wave energy...

  13. Overtopping of Rubble Mound Breakwaters with Front Reservoir

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke

    2007-01-01

    The design and performance of breakwaters with front reservoir are discussed on the basis of physical 2-D model tests with a number of cross sections, in which vertopping discharge and spatial distribution, wave forces on inner parapet walls, and stability of reservoir armour were studied....... The sensitivity of these quantities to the width of the reservoir is discussed. It is demonstrated that front reservoir solutions are more economical than conventional cross section solutions, such as bermed structures and mild slope structures, in cases where low crests and small overtopping discharges...

  14. Ultrasonic wave damage detecting device

    International Nuclear Information System (INIS)

    Miura, Yuichi; Nagao, Tetsuya; Nishi, Yuji; Kubota, Keisuke; Maruyama, Takayuki.

    1994-01-01

    Upon detecting a damage for a joint between a connecting nozzle at the outer circumference of a reactor pressure vessel and pipelines, the present invention greatly shortens the operation time. That is, it is noted that the connecting nozzle has a tapered portion and a small-diameter portion in view of strength. A main magnetic wheel supported on a base of a running vehicle is attracted to the small-diameter portion and an auxiliary magnet wheel is attracted to the tapered portion respectively and they are rolled. This regulate the deviation of the position of the base of the running vehicle in axial direction of the nozzle by the small-diameter portion and the tapered portion. Accordingly, the running vehicle can be circulated along a predetermined course on the outer circumference of the connecting nozzle without using tracks such as an existent ring track. The test can be performed conveniently only by placing the damage detecting device on the connecting nozzle. As a result, preparation time required before the test can remarkably be shortened. (I.S.)

  15. An Innovative Way of Utilizing Wave Energy to Counteract Eutrophication and Hypoxia

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Claeson, Lennart

    2011-01-01

    One of the most urgent environmental issues in 415 coastal systems worldwide is eutrophication and hypoxia. Cause of eutrophication is the rapid increase in intensive agricultural practices, industrial activities, and population growth which together have increased nitrogen and phosphorus flows...... in the environment. This is a major problem in the Baltic Sea. The present study introduces the Wave-Energized Baltic Aeration Pump (WEBAP). This is one floating overtopping device that uses the collected overtopping water to oxygenate the sea bottom in areas suffering from eutrophication. This is done by using...... the driving head of the overtopping water temporarily stored in the reservoir flowing out through a long vertical pipe leading close to the bottom of the sea. The necessary amounts of oxygen and corresponding overtopping volumes in order to have a positive impact in a damaged environment have been considered...

  16. Specification of Instrumentation of Multi MW Wave Dragon Offshore Wave Energy Converter

    DEFF Research Database (Denmark)

    Gilling, Lasse; Kofoed, Jens Peter

    Wave Dragon is a wave energy converter of the overtopping type and is described e.g. in Tedd et. al. (2006). The device has been thoroughly tested on a 1:51.8 scale model in wave laboratories and a 1:4.5 scale model deployed in Nissum Bredning, a large inland waterway in Denmark. Based on the exp......Wave Dragon is a wave energy converter of the overtopping type and is described e.g. in Tedd et. al. (2006). The device has been thoroughly tested on a 1:51.8 scale model in wave laboratories and a 1:4.5 scale model deployed in Nissum Bredning, a large inland waterway in Denmark. Based...

  17. Laboratory Tests in the Development of WaveCat

    Directory of Open Access Journals (Sweden)

    James Allen

    2016-12-01

    Full Text Available WaveCat, a novel overtopping Wave Energy Converter, was tested with the aim of determining its performance under different sea states, establishing a starting point for optimisation of the device, numerical model validation and proof-of-concept for the control systems. The tests were carried out at a 1:30 scale in the Ocean Basin of the COAST Laboratory at University of Plymouth. A state-of-the-art control system was implemented, and overtopping rates and device motions were recorded alongside the wave field. It was observed that power generation is dependent on both the wave height and period, with smaller periods tending to produce greater overtopping rates, and therefore greater power generation, for the same wave height. Due to time constraints in the laboratory, only one configuration of draft/freeboard was tested; with this configuration, overtopping occurred under significant wave heights of 0.083 m or more, corresponding to 2.5 m or more in prototype values. These experimental results form the basis for future development and optimisation of WaveCat.

  18. Model Testing of the Wave Energy Converter Seawave Slot-Cone Generator

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter

    This report presents the results of a preliminary experimental study of the wave energy convert (WEC) Seawave Slot-Cone Generator (SSG). SSG is a WEC utilizing wave overtopping in multiple reservoirs. In the present SSG setup three reservoirs has been used. Model tests have been performed using...... a scale model (length scale 1:15) of a SSG device to be installed on the west coast of the island Kvitsøy near Stavanger, Norway. The tests were carried out at Dept. of Civil Engineering, Aalborg University (AAU) in the 3D deep water wave tank. The model has been subjected to regular and irregular waves...... corresponding to typical conditions off shore from the intended installation site. The overtopping rates for the individual reservoirs have been measured and the potential energy in the overtopping water has been calculated....

  19. Wave energy devices with compressible volumes.

    Science.gov (United States)

    Kurniawan, Adi; Greaves, Deborah; Chaplin, John

    2014-12-08

    We present an analysis of wave energy devices with air-filled compressible submerged volumes, where variability of volume is achieved by means of a horizontal surface free to move up and down relative to the body. An analysis of bodies without power take-off (PTO) systems is first presented to demonstrate the positive effects a compressible volume could have on the body response. Subsequently, two compressible device variations are analysed. In the first variation, the compressible volume is connected to a fixed volume via an air turbine for PTO. In the second variation, a water column separates the compressible volume from another volume, which is fitted with an air turbine open to the atmosphere. Both floating and bottom-fixed, axisymmetric, configurations are considered, and linear analysis is employed throughout. Advantages and disadvantages of each device are examined in detail. Some configurations with displaced volumes less than 2000 m 3 and with constant turbine coefficients are shown to be capable of achieving 80% of the theoretical maximum absorbed power over a wave period range of about 4 s.

  20. Development of a Generic Power Simulation Tool for Overtopping Based WEC

    DEFF Research Database (Denmark)

    Bogarino, Bruno; Kofoed, Jens Peter; Meinert, Palle

    The overtopping based wave energy converters work by collecting the water from waves in one or more reservoirs above the mean sea water level. The water is then evacuated through one or several turbines and thereby produces electrical energy. As the waves in real sea have a stochastic variation...... in wave height and period, it is very difficult to predict how much water the next wave will bring. Thus, for a given wave state, an optimum turbine operating strategy must be found, minimising the sum of head and spilling losses over a certain period of time. This can only be done by modelling...

  1. ICRF Traveling Wave launcher for fusion devices

    International Nuclear Information System (INIS)

    Ragona, R

    2017-01-01

    Ion Cyclotron Resonance Heating and Current Drive is a method that has the ability to heat directly the ions in the Deuterium-Tritrium fuel to the high temperature needed for the fusion reaction to works. The capability of efficiently couple the Radio Frequency power to the plasma plays a big role in the overall performance of a fusion device. A Traveling Wave Antenna in a resonant ring configuration is a good candidate for an Ion Cyclotron Resonance Heating and Current Drive system. It has the capability to increase the coupled power with respect to present designs and to have a highly selective power spectrum that can be peaked around the maximally absorbed wave. It is also insensitive to the loading variations due to fluctuation of the plasma edge increasing the reliability and the efficiency of the system. It works as a low power density launcher due to the possible large number of current carrying elements. (paper)

  2. Second generation wave energy device - the clam concept

    Energy Technology Data Exchange (ETDEWEB)

    Bellamy, N.W.

    1981-01-01

    A device concept is presented which has arisen from a system approach adopted by a research group with considerable experience in the discipline of wave energy. The Clam, which can be classified as a spine-based pneumatic terminator, is deemed to be a second generation wave energy device in that it tries to utilize system components already identified as attractive, while at the same time avoiding known problem areas. A working model of this wave power device at an engineering scale is discussed for trials in real waves. 3 refs.

  3. Overtopping And Rear Slope Stabillity Of Reshaping Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans Falk; Lykke Andersen, Thomas

    2003-01-01

    An experimental study of overtopping and rear slope stability of reshaping breakwaters has been carried out. The variation of those two parameters with crest width, crest freeboard and sea state was investigated. The tests showed that the variation in overtopping discharge with crest freeboard...

  4. Short term wave forecasting, using digital filters, for improved control of Wave Energy Converters

    DEFF Research Database (Denmark)

    Tedd, James; Frigaard, Peter

    2007-01-01

    This paper presents a Digital Filter method for real time prediction of waves incident upon a Wave Energy device. The method transforms waves measured at a point ahead of the device, to expected waves incident on the device. The relationship between these incident waves and power capture is derived...... experimentally. Results are shown form measurements taken on the Wave Dragon prototype device, a floating overtopping device situated in Northern Denmark. In this case the method is able to accurately predict the surface elevation at the device 11.2 seconds before the measurement is made. This is sufficient...... to allow advanced control systems to be developed using this knowledge to significantly improve power capture....

  5. Short term wave forecasting, using digital filters, for improved control of Wave Energy Converters

    Energy Technology Data Exchange (ETDEWEB)

    Tedd, J.; Frigaard, P. [Department of Civil Engineering, Aalborg University, Aalborg (Denmark)

    2007-07-01

    This paper presents a Digital Filter method for real time prediction of waves incident upon a Wave Energy device. The method transforms waves measured at a point ahead of the device, to expected waves incident on the device. The relationship between these incident waves and power capture is derived experimentally. Results are shown form measurements taken on the Wave Dragon prototype device, a floating overtopping device situated in Northern Denmark. In this case the method is able to accurately predict the surface elevation at the device 11.2 seconds before the measurement is made. This is sufficient to allow advanced control systems to be developed using this knowledge to significantly improve power capture.

  6. Spin-wave logic devices based on isotropic forward volume magnetostatic waves

    International Nuclear Information System (INIS)

    Klingler, S.; Pirro, P.; Brächer, T.; Leven, B.; Hillebrands, B.; Chumak, A. V.

    2015-01-01

    We propose the utilization of isotropic forward volume magnetostatic spin waves in modern wave-based logic devices and suggest a concrete design for a spin-wave majority gate operating with these waves. We demonstrate by numerical simulations that the proposed out-of-plane magnetized majority gate overcomes the limitations of anisotropic in-plane magnetized majority gates due to the high spin-wave transmission through the gate, which enables a reduced energy consumption of these devices. Moreover, the functionality of the out-of-plane majority gate is increased due to the lack of parasitic generation of short-wavelength exchange spin waves

  7. Spin-wave logic devices based on isotropic forward volume magnetostatic waves

    Energy Technology Data Exchange (ETDEWEB)

    Klingler, S., E-mail: stefan.klingler@wmi.badw-muenchen.de; Pirro, P.; Brächer, T.; Leven, B.; Hillebrands, B.; Chumak, A. V. [Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern (Germany)

    2015-05-25

    We propose the utilization of isotropic forward volume magnetostatic spin waves in modern wave-based logic devices and suggest a concrete design for a spin-wave majority gate operating with these waves. We demonstrate by numerical simulations that the proposed out-of-plane magnetized majority gate overcomes the limitations of anisotropic in-plane magnetized majority gates due to the high spin-wave transmission through the gate, which enables a reduced energy consumption of these devices. Moreover, the functionality of the out-of-plane majority gate is increased due to the lack of parasitic generation of short-wavelength exchange spin waves.

  8. The Wave Dragon

    DEFF Research Database (Denmark)

    Sørensen, H. C.; Hansen, R.; Friis-Madsen, E.

    2000-01-01

    The Wave Dragon is an offshore wave energy converter of the overtopping type, utilizing a patented wave reflector design to focus the waves towards a ramp, and the overtopping is used for electricity production through a set of Kaplan/propeller hydro turbines. During the last 2 years, excessive...... design an testing has been performed on a scale 1:50 model of the Wave Dragon, and on a scale 1:3:5 model turbine. Thus survivability, overtopping, hydraulic response, turbine performance and feasibility have been verified....

  9. Experimental Research of a New Wave Energy Conversion Device

    Science.gov (United States)

    Lu, Zhongyue; Shang, Jianzhong; Luo, Zirong; Sun, Chongfei; Chen, Gewei

    2018-01-01

    With the increasing tension of contemporary social energy, the development and utilization of renewable energy has become an important development direction. As an important part of renewable energy, wave energy has the characteristics of green environmental protection and abundant reserves, attracting more investment and research. For small marine equipment energy supply problem, this paper puts forward a micro wave energy conversion device as the basic of heaving motion of waves in the ocean. This paper designed a new type of power output device can solve the micro wave energy conversion problem.

  10. Control Strategies for Arrays of Wave Energy Devices

    OpenAIRE

    Westphalen, J; Bacelli, G; Balitsky, P; Ringwood, John

    2011-01-01

    In this paper, we investigate the differences between two control strategies for a two-device linear array of wave energy converters (WEC) for device spacings of 4 to 80 times the device diameter. The WECs operate in heave only and are controlled in real time. The control strategies, called the independent device and global array control, estimate the excitation forces and calculate the optimum vertical velocity trajectory and reactive power take off force to achieve the ...

  11. Preliminary Analysis of a Submerged Wave Energy Device

    Science.gov (United States)

    Wagner, J. R.; Wagner, J. J.; Hayatdavoodi, M.; Ertekin, R. C.

    2016-02-01

    Preliminary analysis of a submerged wave energy harvesting device is presented. The device is composed of a thin, horizontally submerged plate that is restricted to heave oscillations under the influence of surface waves. The submerged plate is oscillating, and it can be attached to a fixed rotor, or a piston, to harvest the wave energy. A fully submerged wave energy converter is preferred over a surface energy convertor due to its durability and less visual and physical distractions it presents. In this study, the device is subject to nonlinear shallow-water waves. Wave loads on the submerged oscillating plate are obtained via the Level I Green-Naghdi equations. The unsteady motion of the plate is obtained by solving the nonlinear equations of motion. The results are obtained for a range of waves with varying heights and periods. The amplitude and period of plate oscillations are analyzed as functions of the wave parameters and plate width. Particular attention is given to the selection of the site of desired wave field. Initial estimation on the amount of energy extraction from the device, located near shore at a given site, is provided.

  12. Gas loading of graphene-quartz surface acoustic wave devices

    Science.gov (United States)

    Whitehead, E. F.; Chick, E. M.; Bandhu, L.; Lawton, L. M.; Nash, G. R.

    2013-08-01

    Graphene was transferred to the propagation path of quartz surface acoustic wave devices and the attenuation due to gas loading of air and argon measured at 70 MHz and 210 MHz and compared to devices with no graphene. Under argon loading, there was no significant difference between the graphene and non-graphene device and the values of measured attenuation agree well with those calculated theoretically. Under air loading, at 210 MHz, there was a significant difference between the non-graphene and graphene devices, with the average value of attenuation obtained with the graphene devices being approximately twice that obtained from the bare quartz devices.

  13. Surface wave photonic device based on porous silicon multilayers

    International Nuclear Information System (INIS)

    Guillermain, E.; Lysenko, V.; Benyattou, T.

    2006-01-01

    Porous silicon is widely studied in the field of photonics due to its interesting optical properties. In this work, we present theoretical and first experimental studies of a new kind of porous silicon photonic device based on optical surface wave. A theoretical analysis of the device is presented using plane-wave approximation. The porous silicon multilayered structures are realized using electrochemical etching of p + -type silicon. Morphological and optical characterizations of the realized structures are reported

  14. Preliminary Load Estimations for DEXA Wave Energy Device - Hanstholm, Denmark

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter

    by DEXA Wave Energy ApS, in regular and irregular wave states, as described in Assessment of Wave Energy Devices. Best Practice as used in Denmark (Frigaard et al., 2008). The length scale of the model was 1:20 compared to a full scale device suitable fro the Danish part of the North Sea, according...... to DEXA Wave Energy ApS. The tests were carried out at Dept. of Civil Engineering, Aalborg University (AAU) in the 3D deep water wave tank. The displacement and force applied to a power take off system, provided by DEXA Wave Energy ApS, were measured and used for calculation of power available...... to the power take-off....

  15. Influence of Buoyancy Control Performance on Power Production by the Wave Dragon Nissum Bredning Prototype

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Tedd, James; Friis-Madsen, E.

    2007-01-01

    This paper reports on the real sea performance of the buoyancy control system of Wave Dragon, a floating wave energy converter using the overtopping principle. The device operates with the full independent control system which has been tested during three years of operation. The impact of the buo...... of the buoyancy control system performance on the power production is noted. This provides motivation and a target for improved control algorithms....

  16. A device for using wave energy

    Energy Technology Data Exchange (ETDEWEB)

    Prokopov, O.I.

    1984-01-01

    An offshore floating platform is used to support an electrical generator and two pontoons fastened on the edges. A horizontal tube located in a housing for two turbine blades rotating in opposite directions is connected to the generator by a shaft housed in a casing. The conical transmission connects the horizontal shafts of the turbine blades to the vertical shaft. When the waves pass near this platform, the pontoons rise up, the platform leans over to one side, and the turbine blades describe an arc, and cause the transmission and generator shaft to turn via the internal shafts. When the wave passes under the support, the raised pontoon drops and the other rises, and the platform leans over in the opposite direction; the blades then rotate in the opposite direction.

  17. Floating attenuator wave energy device: Wavegen HYDRA project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    This report describes research funded by the Department of Trade and Industry (DTI) into the feasibility of developing and constructing a floating attenuator wave energy device known as HYDRA following initial studies by Wavegen. HYDRA is a floating externally tensioned articulated raft wave energy generator based on work by Professor FJM Farley and colleagues during the 1980s. The project's first four work tasks confirmed the theoretical potential of the device but also highlighted significant practical problems in translating that potential into a viable design. It was therefore decided not to proceed further, i.e. not to construct and test a prototype device. The report provides a general description of the device and describes the results of the initial analysis and the first series of model tests. It then discusses device design and component testing and explains the methodology for determining device performance at a particular site and mathematical modelling of a one-third scale device. To help future research and development programmes, the report emphasises the generic problems associated with the development of wave devices.

  18. Launching fast waves in large devices

    International Nuclear Information System (INIS)

    Jacquinot, J.; Bhatnagar, V.P.; Kaye, A.; Brown, T.

    1994-01-01

    Design features of JET A2-antennae including that of remote location of ceramic are outlined. These antennae are being installed in preparation for the new divertor phase of JET that will commence in 1994. The experience of antenna design gained at JET is carried forward to present an outline in blanket/shield design of an antenna for launching fast waves in ITER for heating and current drive. Further, a new wide band antenna the so called 'violin antenna' is presented that features high plasma coupling resistance in selected bands in the 20-85 MHz frequency range. (author)

  19. Guided-wave acousto-optics interactions, devices, and applications

    CERN Document Server

    1990-01-01

    The field of integrated- or guided-wave optics has experienced significant and continuous growth since its inception in the late 1960s. There has been a considerable increase in research and development activity in this field worldwide and some significant advances in the realization of working in­ tegrated optic devices and modules have been made in recent years. In fact, there have already been some commercial manufacturing and technical ap­ plications of such devices and modules. The guided-wave-acoustooptics involving Bragg interactions between guided optical waves and surface acoustic waves is one of the areas of in­ tegrated-optics that has reached some degree of scientific and technological maturity. This topical volume is devoted to an in-depth treatment of this emerging branch of science and technology. Presented in this volume are concise treatments on bulk-wave acoustooptics, guided-wave optics, and surface acoustic waves, and detailed studies of guided-wave acoustooptic Bragg diffraction in thr...

  20. Numerical Simulation of Wake Effects in the Lee of a Farm of Wave Dragon Wave Energy Converters

    DEFF Research Database (Denmark)

    Beels, C.; Troch, P.; De Visch, K.

    2009-01-01

    . In this paper wake effects in the lee of a single Wave Dragon WEC and multiple Wave Dragon WECs are studied in a time-dependent mild-slope equation model. The Wave Dragon WEC is a floating offshore converter of the overtopping type. The water volume of overtopped waves is first captured in a basin above mean...

  1. Wave Dragon

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter; Sørensen, H. C.

    1998-01-01

    This paper concerns with the development of the wave energy converter (WEC) Wave Dragon. This WEC is based on the overtopping principle. An overview of the performed research done concerning the Wave Dragon over the past years is given, and the results of one of the more comprehensive studies, co...

  2. Discrete microfluidics based on aluminum nitride surface acoustic wave devices

    OpenAIRE

    Zhou, J.; Pang, H.F.; Garcia-Gancedo, L.; Iborra, E.; Clement, M.; De Miguel-Ramos, M.; Jin, H.; Luo, J.K.; Smith, S.; Dong, S.R.; Wang, D.M.; Fu, Y.Q.

    2015-01-01

    To date, most surface acoustic wave (SAW) devices have been made from bulk piezoelectric materials, such as quartz, lithium niobate or lithium tantalite. These bulk materials are brittle, less easily integrated with electronics for control and signal processing, and difficult to realize multiple wave modes or apply complex electrode designs. Using thin film SAWs makes it convenient to integrate microelectronics and multiple sensing or microfluidics techniques into a lab-on-a-chip with low cos...

  3. Research on a new wave energy absorption device

    Science.gov (United States)

    Lu, Zhongyue; Shang, Jianzhong; Luo, Zirong; Sun, Chongfei; Zhu, Yiming

    2018-01-01

    To reduce impact of global warming and the energy crisis problems caused by pollution of energy combustion, the research on renewable and clean energies becomes more and more important. This paper designed a new wave absorption device, and also gave an introduction on its mechanical structure. The flow tube model is analyzed, and presented the formulation of the proposed method. To verify the principle of wave absorbing device, an experiment was carried out in a laboratory environment, and the results of the experiment can be applied for optimizing the structure design of output power.

  4. Guided wave opto-acoustic device

    Science.gov (United States)

    Jarecki, Jr., Robert L.; Rakich, Peter Thomas; Camacho, Ryan; Shin, Heedeuk; Cox, Jonathan Albert; Qiu, Wenjun; Wang, Zheng

    2016-02-23

    The various technologies presented herein relate to various hybrid phononic-photonic waveguide structures that can exhibit nonlinear behavior associated with traveling-wave forward stimulated Brillouin scattering (forward-SBS). The various structures can simultaneously guide photons and phonons in a suspended membrane. By utilizing a suspended membrane, a substrate pathway can be eliminated for loss of phonons that suppresses SBS in conventional silicon-on-insulator (SOI) waveguides. Consequently, forward-SBS nonlinear susceptibilities are achievable at about 3000 times greater than achievable with a conventional waveguide system. Owing to the strong phonon-photon coupling achievable with the various embodiments, potential application for the various embodiments presented herein cover a range of radiofrequency (RF) and photonic signal processing applications. Further, the various embodiments presented herein are applicable to applications operating over a wide bandwidth, e.g. 100 MHz to 50 GHz or more.

  5. Underwater Shock Wave Research Applied to Therapeutic Device Developments

    Science.gov (United States)

    Takayama, K.; Yamamoto, H.; Shimokawa, H.

    2013-07-01

    The chronological development of underwater shock wave research performed at the Shock Wave Research Center of the Institute of Fluid Science at the Tohoku University is presented. Firstly, the generation of planar underwater shock waves in shock tubes and their visualization by using the conventional shadowgraph and schlieren methods are described. Secondly, the generation of spherical underwater shock waves by exploding lead azide pellets weighing from several tens of micrograms to 100 mg, that were ignited by irradiating with a Q-switched laser beam, and their visualization by using double exposure holographic interferometry are presented. The initiation, propagation, reflection, focusing of underwater shock waves, and their interaction with various interfaces, in particular, with air bubbles, are visualized quantitatively. Based on such a fundamental underwater shock wave research, collaboration with the School of Medicine at the Tohoku University was started for developing a shock wave assisted therapeutic device, which was named an extracorporeal shock wave lithotripter (ESWL). Miniature shock waves created by irradiation with Q-switched HO:YAG laser beams are studied, as applied to damaged dysfunctional nerve cells in the myocardium in a precisely controlled manner, and are effectively used to design a catheter for treating arrhythmia.

  6. Surface acoustic wave coding for orthogonal frequency coded devices

    Science.gov (United States)

    Malocha, Donald (Inventor); Kozlovski, Nikolai (Inventor)

    2011-01-01

    Methods and systems for coding SAW OFC devices to mitigate code collisions in a wireless multi-tag system. Each device producing plural stepped frequencies as an OFC signal with a chip offset delay to increase code diversity. A method for assigning a different OCF to each device includes using a matrix based on the number of OFCs needed and the number chips per code, populating each matrix cell with OFC chip, and assigning the codes from the matrix to the devices. The asynchronous passive multi-tag system includes plural surface acoustic wave devices each producing a different OFC signal having the same number of chips and including a chip offset time delay, an algorithm for assigning OFCs to each device, and a transceiver to transmit an interrogation signal and receive OFC signals in response with minimal code collisions during transmission.

  7. 3 Years Experience with Energy Production on the Nissum Bredning Wave Dragon Prototype

    DEFF Research Database (Denmark)

    Frigaard, Peter; Tedd, James; Kofoed, Jens Peter

    2006-01-01

    Wave Dragon is a floating wave energy converter working by extracting energy principally by means of overtopping of waves into a reservoir. A 1:4.5 scale prototype has been sea tested for 20 months. This paper presents results from testing, experiences gained and developments made during this ext......Wave Dragon is a floating wave energy converter working by extracting energy principally by means of overtopping of waves into a reservoir. A 1:4.5 scale prototype has been sea tested for 20 months. This paper presents results from testing, experiences gained and developments made during...... this extended period. The prototype is highly instrumented. The overtopping characteristic and the power produced are presented here. This has enabled comparison between the prototype and earlier results from both laboratory model and computer simulation. This gives the optimal operating point and the expected...... power of the device. The project development team has gained much soft experience from working in the harsh offshore environment. In particular the effect of marine growth in the draft tubes of the turbines has been investigated. The control of the device has been a focus for development as is operates...

  8. An oxygen pressure sensor using surface acoustic wave devices

    Science.gov (United States)

    Leighty, Bradley D.; Upchurch, Billy T.; Oglesby, Donald M.

    1993-01-01

    Surface acoustic wave (SAW) piezoelectric devices are finding widespread applications in many arenas, particularly in the area of chemical sensing. We have developed an oxygen pressure sensor based on coating a SAW device with an oxygen binding agent which can be tailored to provide variable sensitivity. The coating is prepared by dissolving an oxygen binding agent in a toluene solution of a copolymer which is then sprayed onto the surface of the SAW device. Experimental data shows the feasibility of tailoring sensors to measure the partial pressure of oxygen from 2.6 to 67 KPa (20 to 500 torr). Potential applications of this technology are discussed.

  9. The environmental interactions of tidal and wave energy generation devices

    International Nuclear Information System (INIS)

    Frid, Chris; Andonegi, Eider; Depestele, Jochen; Judd, Adrian; Rihan, Dominic; Rogers, Stuart I.; Kenchington, Ellen

    2012-01-01

    Global energy demand continues to grow and tidal and wave energy generation devices can provide a significant source of renewable energy. Technological developments in offshore engineering and the rising cost of traditional energy means that offshore energy resources will be economic in the next few years. While there is now a growing body of data on the ecological impacts of offshore wind farms, the scientific basis on which to make informed decisions about the environmental effects of other offshore energy developments is lacking. Tidal barrages have the potential to cause significant ecological impacts particularly on bird feeding areas when they are constructed at coastal estuaries or bays. Offshore tidal stream energy and wave energy collectors offer the scope for developments at varying scales. They also have the potential to alter habitats. A diversity of designs exist, including floating, mid-water column and seabed mounted devices, with a variety of moving-part configurations resulting in a unique complex of potential environmental effects for each device type, which are discussed to the extent possible. - Highlights: ► We review the environmental impacts of tidal barrages and fences, tidal stream farms and wave energy capture devices. ► Impacts on habitats, species and the water column, and effects of noise and electromagnetic fields are considered. ► Tidal barrages can cause significant impacts on bird feeding areas when constructed at coastal estuaries or bays. ► Wave energy collectors can alter water column and sea bed habitats locally and over large distances.

  10. A capacitive device approach to gravitational wave detection

    International Nuclear Information System (INIS)

    Mours, B.; Yvert, M.

    1988-05-01

    The possible use of a capacitive device to detect gravitational waves is discussed. Special emphasis is put on the detection of permanent periodic sources. The intrinsic properties of such a method, its sensitivity, directionality and its wide frequency band, makes it a very appealing one

  11. Description of the Power Take-off System on board the Wave Dragon Prototype

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter; Knapp, Wilfried

    2005-01-01

    The paper describes the power take-off system of the overtopping based wave energy converter Wave Dragon (WD). Focus is put on the hydro turbine arrangement used for the extraction of the potential energy in the water obtained by wave overtopping of the ramp into the reservoir.......The paper describes the power take-off system of the overtopping based wave energy converter Wave Dragon (WD). Focus is put on the hydro turbine arrangement used for the extraction of the potential energy in the water obtained by wave overtopping of the ramp into the reservoir....

  12. Surface Acoustic Wave Devices for Harsh Environment Wireless Sensing

    Directory of Open Access Journals (Sweden)

    David W. Greve

    2013-05-01

    Full Text Available Langasite surface acoustic wave devices can be used to implement harsh-environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensor with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity.

  13. Overtopping of Rubble Mound Breakwaters with Front Reservoir

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke

    2006-01-01

    The admissible overtopping discharge is a key parameter in fundamental design of breakwaters. Quite often there is a wish to limit the crest level of the structure, mainly for aesthetic reasons as a high structure might block the sea view from restaurants, promenades etc.......The admissible overtopping discharge is a key parameter in fundamental design of breakwaters. Quite often there is a wish to limit the crest level of the structure, mainly for aesthetic reasons as a high structure might block the sea view from restaurants, promenades etc....

  14. Micro and nano devices in passive millimetre wave imaging systems

    Science.gov (United States)

    Appleby, R.

    2013-06-01

    The impact of micro and nano technology on millimetre wave imaging from the post war years to the present day is reviewed. In the 1950s whisker contacted diodes in mixers and vacuum tubes were used to realise both radiometers and radars but required considerable skill to realise the performance needed. Development of planar semiconductor devices such as Gunn and Schottky diodes revolutionised mixer performance and provided considerable improvement. The next major breakthrough was high frequency transistors based on gallium arsenide which were initially used at intermediate frequencies but later after further development at millimeter wave frequencies. More recently Monolithic Microwave Integrated circuits(MMICs) offer exceptional performance and the opportunity for innovative design in passive imaging systems. In the future the use of micro and nano technology will continue to drive system performance and we can expect to see integration of antennae, millimetre wave and sub millimetre wave circuits and signal processing.

  15. SU-8 Guiding Layer for Love Wave Devices

    Directory of Open Access Journals (Sweden)

    Michael I. Newton

    2007-11-01

    Full Text Available SU-8 is a technologically important photoresist used extensively for thefabrication of microfluidics and MEMS, allowing high aspect ratio structures to beproduced. In this work we report the use of SU-8 as a Love wave sensor guiding layerwhich allows the possibility of integrating a guiding layer with flow cell during fabrication.Devices were fabricated on ST-cut quartz substrates with a single-single finger design suchthat a surface skimming bulk wave (SSBW at 97.4 MHz was excited. SU-8 polymer layerswere successively built up by spin coating and spectra recorded at each stage; showing afrequency decrease with increasing guiding layer thickness. The insertion loss andfrequency dependence as a function of guiding layer thickness was investigated over thefirst Love wave mode. Mass loading sensitivity of the resultant Love wave devices wasinvestigated by deposition of multiple gold layers. Liquid sensing using these devices wasalso demonstrated; water-glycerol mixtures were used to demonstrate sensing of density-viscosity and the physical adsorption and removal of protein was also assessed usingalbumin and fibrinogen as model proteins.

  16. Impacts of wave energy conversion devices on local wave climate: observations and modelling from the Perth Wave Energy Project

    Science.gov (United States)

    Hoeke, Ron; Hemer, Mark; Contardo, Stephanie; Symonds, Graham; Mcinnes, Kathy

    2016-04-01

    As demonstrated by the Australian Wave Energy Atlas (AWavEA), the southern and western margins of the country possess considerable wave energy resources. The Australia Government has made notable investments in pre-commercial wave energy developments in these areas, however little is known about how this technology may impact local wave climate and subsequently affect neighbouring coastal environments, e.g. altering sediment transport, causing shoreline erosion or accretion. In this study, a network of in-situ wave measurement devices have been deployed surrounding the 3 wave energy converters of the Carnegie Wave Energy Limited's Perth Wave Energy Project. This data is being used to develop, calibrate and validate numerical simulations of the project site. Early stage results will be presented and potential simulation strategies for scaling-up the findings to larger arrays of wave energy converters will be discussed. The intended project outcomes are to establish zones of impact defined in terms of changes in local wave energy spectra and to initiate best practice guidelines for the establishment of wave energy conversion sites.

  17. Report on feasibility study of the Clam Wave Energy Device

    Energy Technology Data Exchange (ETDEWEB)

    1979-04-01

    The main emphasis of the feasibility study has been towards producing an acceptable spine design for the Clam wave energy converter. Concrete and steel designs based on a mathematical model of the waveloading have been produced. Progress is also reported in the design of a bellows for a low-pressure air power transmission system. A narrow wave tank and scale model have been constructed in order to carry out a test programme on various aspects of the device's construction and performance.

  18. Source Illusion Devices for Flexural Lamb Waves Using Elastic Metasurfaces.

    Science.gov (United States)

    Liu, Yongquan; Liang, Zixian; Liu, Fu; Diba, Owen; Lamb, Alistair; Li, Jensen

    2017-07-21

    Inspired by recent demonstrations of metasurfaces in achieving reduced versions of electromagnetic cloaks, we propose and experimentally demonstrate source illusion devices to manipulate flexural waves using metasurfaces. The approach is particularly useful for elastic waves due to the lack of form invariance in usual transformation methods. We demonstrate compact and simple-to-implement metasurfaces for shifting, transforming, and splitting a point source. The effects are measured to be broadband and robust against a change of source positions, with agreement from numerical simulations and the Huygens-Fresnel theory. The proposed method is potentially useful for applications such as nondestructive testing, high-resolution ultrasonography, and advanced signal modulation.

  19. A Simple model for breach formation by overtopping

    Energy Technology Data Exchange (ETDEWEB)

    Trousseau, P. [Hydro-Quebec, Montreal, PQ (Canada); Kahawita, R. [Ecole Polytechnique, Montreal, PQ (Canada)

    2006-07-01

    Failures in earth or rockfill dams are often caused by overtopping of the crest, leading to initiation and uncontrolled progression of a breach. Overtopping may occur because of large inflows into the reservoir caused by excessive rainfall or by the failure of an upstream dam that causes a large volume of water to suddenly arrive at the downstream reservoir thus rapidly exceeding the storage and spillway evacuation capacity. Breach formation in a rockfill or earthfill dike due to overtopping of the crest is a complex process as it involves interaction between the hydraulics of the flow and the erosion characteristics of the fill material. This paper presented a description and validation of a simple parametric model for breach formation due to overtopping. A study was conducted to model, as closely as possible, the physical processes involved within the restriction of the simplified analysis. The objective of the study was to predict the relevant timescales for the phenomenon leading to a prediction of the outflow hydrograph. The model has been validated on the Oros dam failure in Brazil as well as on embankment tests conducted at Rosvatn, Norway. It was concluded that the major impediment to the development of breach erosion models for use as predictive tools is in the characterization of the erosion behaviour. 19 refs., 2 tabs., 9 figs.

  20. The environmental interactions of tidal and wave energy generation devices

    OpenAIRE

    Frid, C.; Andonegi, E.; Depestele, J.; Judd, A.; Rihan, D.; Rogers, S.I.; Kenchington, E.

    2012-01-01

    Global energy demand continues to grow and tidal and wave energy generation devices can provide a significant source of renewable energy. Technological developments in offshore engineering and the rising cost of traditional energy means that offshore energy resources will be economic in the next few years. While there is now a growing body of data on the ecological impacts of offshore wind farms, the scientific basis on which to make informed decisions about the environmental effects of other...

  1. The environmental interactions of tidal and wave energy generation devices

    Energy Technology Data Exchange (ETDEWEB)

    Frid, Chris, E-mail: c.l.j.frid@liv.ac.uk [School of Environmental Sciences, University of Liverpool, Crown Street, Liverpool, L69 7ZB (United Kingdom); Andonegi, Eider, E-mail: eandonegi@azti.es [AZTI-Tecnalia, Txatxarramendi ugartea, z/g E-48395 Sukarrieta (Bizkaia) (Spain); Depestele, Jochen, E-mail: jochen.depestele@ilvo.vlaanderen.be [Institute for Agricultural and Fisheries Research, Ankerstraat 1, B-8400 Oostende (Belgium); Judd, Adrian, E-mail: Adrian.Judd@cefas.co.uk [Centre for Environment, Fisheries and Aquaculture Science , Lowestoft Laboratory, Pakefield Road, Lowestoft NR33 0HT United Kingdom (United Kingdom); Rihan, Dominic, E-mail: Dominic.RIHAN@ec.europa.eu [Irish Sea Fisheries Board, P.O. Box 12 Dun Laoghaire, Co. Dublin (Ireland); Rogers, Stuart I., E-mail: stuart.rogers@cefas.co.uk [Centre for Environment, Fisheries and Aquaculture Science , Lowestoft Laboratory, Pakefield Road, Lowestoft NR33 0HT United Kingdom (United Kingdom); Kenchington, Ellen, E-mail: Ellen.Kenchington@dfo-mpo.gc.ca [Fisheries and Oceans Canada, Bedford Institute of Oceanography, P.O. Box 1006, Dartmouth Canada, NS B2Y 4A2 (Canada)

    2012-01-15

    Global energy demand continues to grow and tidal and wave energy generation devices can provide a significant source of renewable energy. Technological developments in offshore engineering and the rising cost of traditional energy means that offshore energy resources will be economic in the next few years. While there is now a growing body of data on the ecological impacts of offshore wind farms, the scientific basis on which to make informed decisions about the environmental effects of other offshore energy developments is lacking. Tidal barrages have the potential to cause significant ecological impacts particularly on bird feeding areas when they are constructed at coastal estuaries or bays. Offshore tidal stream energy and wave energy collectors offer the scope for developments at varying scales. They also have the potential to alter habitats. A diversity of designs exist, including floating, mid-water column and seabed mounted devices, with a variety of moving-part configurations resulting in a unique complex of potential environmental effects for each device type, which are discussed to the extent possible. - Highlights: Black-Right-Pointing-Pointer We review the environmental impacts of tidal barrages and fences, tidal stream farms and wave energy capture devices. Black-Right-Pointing-Pointer Impacts on habitats, species and the water column, and effects of noise and electromagnetic fields are considered. Black-Right-Pointing-Pointer Tidal barrages can cause significant impacts on bird feeding areas when constructed at coastal estuaries or bays. Black-Right-Pointing-Pointer Wave energy collectors can alter water column and sea bed habitats locally and over large distances.

  2. Worlds Largest Wave Energy Project 2007 in Wales

    DEFF Research Database (Denmark)

    Christensen, Lars; Friis-Madsen, Erik; Kofoed, Jens Peter

    2006-01-01

    This paper introduces world largest wave energy project being developed in Wales and based on one of the leading wave energy technologies. The background for the development of wave energy, the total resource ands its distribution around the world is described. In contrast to wind energy turbines...... Dragon has to be scaled in accordance with the wave climate at the deployment site, which makes the Welch demonstrator device the worlds largest WEC so far with a total width of 300 meters. The project budget, the construction methods and the deployment site are also given....... a large number of fundamentally different technologies are utilised to harvest wave energy. The Wave Dragon belongs to the wave overtopping class of converters and the paper describes the fundamentals and the technical solutions used in this wave energy converter. An offshore floating WEC like the Wave...

  3. The 'CETO' wave power generation devices

    Energy Technology Data Exchange (ETDEWEB)

    Profitt, Michael

    2007-07-01

    Renewable Energy Holdings plc (REH) is an international company established to be an operator of, and undertake active investments in both proven and innovative renewable energy technologies. The CETO devices have been developed in Western Australia by Seapower Pacific PTY Ltd (SPPL), a subsidiary of Renewable Energy Holdings Plc (REH). This paper reports on the technology and also includes the findings from an independent technical appraisal undertaken by PB Power. The CETO device consists primarily of a novel pump anchored to the seabed and driven by a spherical buoyant actuator that collects wave energy and transmits it to the pump. High pressure seawater is delivered ashore where it can be used to drive a turbine to generate electricity or passed through a reverse osmosis desalination unit to produce fresh water. The competitive edge of CETO against other current wave and tidal generation devices: Electricity generated onshore (using well-proven hydro-power technology); Low cost mass produced device; Simplified infrastructure from pumping pressurised sea water ashore rather than electricity; Allows shore-based desalination; Modular design and self deployment; and, Transport in standard containers.

  4. Traveling-wave device with mass flux suppression

    Science.gov (United States)

    Swift, Gregory W.; Backhaus, Scott N.; Gardner, David L.

    2000-01-01

    A traveling-wave device is provided with the conventional moving pistons eliminated. Acoustic energy circulates in a direction through a fluid within a torus. A side branch may be connected to the torus for transferring acoustic energy into or out of the torus. A regenerator is located in the torus with a first heat exchanger located on a first side of the regenerator downstream of the regenerator relative to the direction of the circulating acoustic energy; and a second heat exchanger located on an upstream side of the regenerator. The improvement is a mass flux suppressor located in the torus to minimize time-averaged mass flux of the fluid. In one embodiment, the device further includes a thermal buffer column in the torus to thermally isolate the heat exchanger that is at the operating temperature of the device.

  5. Innovative wave energy device applied to coastal observatory systems

    Science.gov (United States)

    Marcelli, Marco; Bonamano, Simone; Piermattei, Viviana; Scanu, Sergio; Paladini de Mendoza, Francesco; Martellucci, Riccardo; Maximo, Peviani

    2017-04-01

    Marine environment is one of the most promising sources of renewable energy, whose exploitation could have an effect on several application fields. This work presents the design of an innovative device based on the Oscillating Water Column (OWC), that allows to convert wave energy into electricity, suitable for the typical Mediterranean wave climate. The flexibility of the device permits its installation either in deep or shallow waters, with reduced costs of deployment, maintenance and connection to the grid. Furthermore, the replicability of the design allows the device to be installed in array of several number of similar units. The technical concept is to convey the sea water within a vertical pipe, in which the water movements activate a rotor connected to a generator that transforms the energy of the water motion into electricity. The hydrodynamic design of the pipe is built to minimize the losses due to friction and turbulence and to exploit the maximum possible energy from wave motion. The wave energy is directly absorbed by the rotational movement of the turbine blades located in the water itself allowing a further reduction of the energy losses associated with the transformation of the linear water motion into electrical generation in the air phase (typical configuration of the OWC devices). In this work the device components are described considering two possible configurations that use a Wells turbine or a Bulb type turbine. The system can be realized at a low cost, because of the modularity of the device project, which allows large freedom of sizes and placements, being able to be installed both individually and in arrays. The modularity, associated with the fact that the main elements of the system are available on the market, makes the device particularly attractive from the economic point of view. Finally, it is realized with a high constructive flexibility: the proposed system can be transported floating and moored to existing coastal structures or

  6. Contribution to coherent atom optics - Design of multiple wave devices

    International Nuclear Information System (INIS)

    Impens, F.

    2008-03-01

    The theoretical work presented in this manuscript addresses two complementary issues in coherent atom optics. The first part addresses the perspectives offered by coherent atomic sources through the design of two experiment involving the levitation of a cold atomic sample in a periodic series of light pulses, and for which coherent atomic clouds are particularly well-suited. These systems appear as multiple wave atom interferometers. A striking feature of these experiments is that a unique system performs both the sample trapping and interrogation. To obtain a transverse confinement, a novel atomic lens is proposed, relying on the interaction between an atomic wave with a spherical light wave. The sensitivity of the sample trapping towards the gravitational acceleration and towards the pulse frequencies is exploited to perform the desired measurement. These devices constitute atomic wave resonators in momentum space, which is a novel concept in atom optics. A second part develops new theoretical tools - most of which inspired from optics - well-suited to describe the propagation of coherent atomic sources. A phase-space approach of the propagation, relying on the evolution of moments, is developed and applied to study the low-energy dynamics of Bose-Einstein condensates. The ABCD method of propagation for atomic waves is extended beyond the linear regime to account perturbatively for mean-field atomic interactions in the atom-optical aberration-less approximation. A treatment of the atom laser extraction enabling one to describe aberrations in the atomic beam, developed in collaboration with the Atom Optics group at the Institute of Optics, is exposed. Last, a quality factor suitable for the characterization of diluted matter waves in a general propagation regime has been proposed. (author)

  7. Wireless device for activation of an underground shock wave absorber

    Science.gov (United States)

    Chikhradze, M.; Akhvlediani, I.; Bochorishvili, N.; Mataradze, E.

    2011-10-01

    The paper describes the mechanism and design of the wireless device for activation of energy absorber for localization of blast energy in underground openings. The statistics shows that the greatest share of accidents with fatal results associate with explosions in coal mines due to aero-methane and/or air-coal media explosion. The other significant problem is terrorist or accidental explosions in underground structures. At present there are different protective systems to reduce the blast energy. One of the main parts of protective Systems is blast Identification and Registration Module. The works conducted at G. Tsulukidze Mining Institute of Georgia enabled to construct the wireless system of explosion detection and mitigation of shock waves. The system is based on the constant control on overpressure. The experimental research continues to fulfill the system based on both threats, on the constant control on overpressure and flame parameters, especially in underground structures and coal mines. Reaching the threshold value of any of those parameters, the system immediately starts the activation. The absorber contains a pyrotechnic device ensuring the discharge of dispersed water. The operational parameters of wireless device and activation mechanisms of pyrotechnic element of shock wave absorber are discussed in the paper.

  8. Supersonic wave detection method and supersonic detection device

    International Nuclear Information System (INIS)

    Machida, Koichi; Seto, Takehiro; Ishizaki, Hideaki; Asano, Rin-ichi.

    1996-01-01

    The present invention provides a method of and device for a detection suitable to a channel box which is used while covering a fuel assembly of a BWR type reactor. Namely, a probe for transmitting/receiving supersonic waves scans on the surface of the channel box. A data processing device determines an index showing a selective orientation degree of crystal direction of the channel box based on the signals received by the probe. A judging device compares the determined index with a previously determined allowable range to judge whether the channel box is satisfactory or not based on the result of the comparison. The judgement are on the basis that (1) the bending of the channel box is caused by the difference of elongation of opposed surfaces, (2) the elongation due to irradiation is caused by the selective orientation of crystal direction, and (3) the bending of the channel box can be suppressed within a predetermined range by suppressing the index determined by the measurement of supersonic waves having a correlation with the selective orientation of the crystal direction. As a result, the performance of the channel box capable of enduring high burnup region can be confirmed in a nondestructive manner. (I.S.)

  9. Spin wave absorber generated by artificial surface anisotropy for spin wave device network

    Directory of Open Access Journals (Sweden)

    Naoki Kanazawa

    2016-09-01

    Full Text Available Spin waves (SWs have the potential to reduce the electric energy loss in signal processing networks. The SWs called magnetostatic forward volume waves (MSFVWs are advantageous for networking due to their isotropic dispersion in the plane of a device. To control the MSFVW flow in a processing network based on yttrium iron garnet, we developed a SW absorber using artificial structures. The mechanical surface polishing method presented in this work can well control extrinsic damping without changing the SW dispersion of the host material. Furthermore, enhancement of the ferromagnetic resonance linewidth over 3 Oe was demonstrated.

  10. InP Devices For Millimeter-Wave Monolithic Circuits

    Science.gov (United States)

    Binari, S. C.; Neidert, R. E.; Dietrich, H. B.

    1989-11-01

    High efficiency, mm-wave operation has been obtained from lateral transferred-electron devices (TEDs) designed with a high resistivity region located near the cathode contact. At 29.9 GHz, a CW power output of 29.1 mW with a conversion efficiency of 6.7% has been achieved with cavity-tuned discrete devices. This result represents the highest power output and efficiency of a lateral TED in this frequency range. The lateral devices also had a CW power output of 0.4 mW at 98.5 GHz and 0.9 mW at 75.2 GHz. In addition, a monolithic oscillator incorporating the lateral TED has been demonstrated at 79.9 GHz. InP Schottky-barrier diodes have been fabricated using selective MeV ion implantation into semi-insulating InP substrates. Using Si implantation with energies of up to 6.0 MeV, n+ layers as deep as 3 μm with peak carrier concentrations of 2 x 1018 cm-3 have been obtained. These devices have been evaluated as mixers and detectors at 94 GHz and have demonstrated a conversion loss of 7.6 dB and a zero-bias detector sensitivity as high as 400 mV/mW.

  11. On the fundamental performance of the floating offshore wave power device (FOWAD)

    International Nuclear Information System (INIS)

    Hotta, H.; Washio, Y.; Miyazaki, T.

    1990-01-01

    This paper reports on the wave power absorption, wave dissipation, mooring line tension and oscillation in regular and irregular (long created and short created) waves of the floating offshore wave power device (FOWAD) that were measured and analyzed by a scale model test in a wave tank. FOWAD is an oscillating water column type device equipped with air turbine generators, and air chambers facing the waves. Therefore, it belongs in the close of terminator type wave power devices. It has several projecting walls in front of each air chamber, several buoyancy compartments behind each chamber and stabilizer at the keel. The measured data indicates that, the performance and stability were improved in comparison with former terminator type devices, FOWAD absorbed about 30% of wave power and mooring line tension was within the limits of safety even in rough seas. Nevertheless the performance for dissipation of waves can be improved. This paper describes on the results of the model test and subsequent analysis

  12. Scale Effects Related to Small Physical Modelling of Overtopping of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke

    2009-01-01

    By comparison of overtopping discharges recorded in prototype and small scale physical models it was demonstrated in the EU-CLASH project that small scale tests significantly underestimate smaller discharges. Deviations in overtopping are due to model and scale effects. These effects are discusse...... armour on the upper part of the slope. This effect is believed to be the main reason for the found deviations between overtopping in prototype and small scale tests....

  13. Economic Assessment of Overtopping BReakwater for Energy Conversion (OBREC: A Case Study in Western Australia

    Directory of Open Access Journals (Sweden)

    Pasquale Contestabile

    2016-12-01

    Full Text Available This paper constructs an optimal configuration assessment, in terms of the financial returns, of the Overtopping BReakwater for wave Energy Conversion (OBREC. This technology represents a hybrid wave energy harvester, totally embedded in traditional rubble mound breakwaters. Nine case studies along the southern coast of Western Australia have been analysed. The technique provides tips on how to estimate the quality of the investments, for benchmarking with different turbine strategy layouts and overlapping with the costs of traditional rubble mound breakwaters. Analyses of the offshore and nearshore wave climate have been studied by a high resolution coastal propagation model, forced with wave data from the European Centre for Medium-Range Weather Forecasts (ECMWF. Inshore wave conditions have been used to quantify the exploitable resources. It has been demonstrated that the optimal investment strategy is nonlinearly dependent on potential electricity production due to outer technical constraints. The work emphasizes the importance of integrating energy production predictions in an economic decision framework for prioritizing adaptation investments.

  14. The observation of nonlinear ion cyclotron wave excitation during high-harmonic fast wave heating in the large helical device

    International Nuclear Information System (INIS)

    Kasahara, H.; Seki, T.; Kumazawa, R.; Saito, K.; Mutoh, T.; Kubo, S.; Shimozuma, T.; Igami, H.; Yoshimura, Y.; Takahashi, H.; Yamada, I.; Tokuzawa, T.; Ohdachi, S.; Morita, S.; Nomura, G.; Shimpo, F.; Komori, A.; Motojima, O.; Oosako, T.; Takase, Y.

    2008-01-01

    A wave detector, a newly designed magnetic probe, is installed in the large helical device (LHD). This wave detector is a 100-turn loop coil with electrostatic shield. Comparing a one-loop coil to this detector, this detector has roughly constant power coupling in the lower frequency range of 40 MHz, and it can easily detect magnetic wave in the frequency of a few megahertz. During high-harmonic fast wave heating, lower frequency waves (<10 MHz) were observed in the LHD for the first time, and for the power density threshold of lower frequency wave excitation (7.5 MHz) the power density of excited pumped wave (38.47 MHz) was approximately -46 dBm/Hz. These lower frequencies are kept constant for electron density and high energy particle distribution, and these lower frequency waves seem to be ion cyclotron waves caused by nonlinear wave-particle interaction, for example, parametric decay instability.

  15. Detecting cavitation in vivo from shock-wave therapy devices

    Science.gov (United States)

    Matula, Thomas J.; Yu, Jinfei; Bailey, Michael R.

    2005-04-01

    Extracorporeal shock-wave therapy (ESWT) has been used as a treatment for plantar faciitis, lateral epicondylitis, shoulder tendonitis, non-unions, and other indications where conservative treatments have been unsuccessful. However, in many areas, the efficacy of SW treatment has not been well established, and the mechanism of action, particularly the role of cavitation, is not well understood. Research indicates cavitation plays an important role in other ultrasound therapies, such as lithotripsy and focused ultrasound surgery, and in some instances, cavitation has been used as a means to monitor or detect a biological effect. Although ESWT can generate cavitation easily in vitro, it is unknown whether or not cavitation is a significant factor in vivo. The purpose of this investigation is to use diagnostic ultrasound to detect and monitor cavitation generated by ESWT devices in vivo. Diagnostic images are collected at various times during and after treatment. The images are then post-processed with image-processing algorithms to enhance the contrast between bubbles and surrounding tissue. The ultimate goal of this research is to utilize cavitation as a means for optimizing shock wave parameters such as amplitude and pulse repetition frequency. [Work supported by APL internal funds and NIH DK43881 and DK55674.

  16. Advanced, High Power, Next Scale, Wave Energy Conversion Device

    Energy Technology Data Exchange (ETDEWEB)

    Mekhiche, Mike [Principal Investigator; Dufera, Hiz [Project Manager; Montagna, Deb [Business Point of Contact

    2012-10-29

    The project conducted under DOE contract DE‐EE0002649 is defined as the Advanced, High Power, Next Scale, Wave Energy Converter. The overall project is split into a seven‐stage, gated development program. The work conducted under the DOE contract is OPT Stage Gate III work and a portion of Stage Gate IV work of the seven stage product development process. The project effort includes Full Concept Design & Prototype Assembly Testing building on our existing PowerBuoy technology to deliver a device with much increased power delivery. Scaling‐up from 150kW to 500kW power generating capacity required changes in the PowerBuoy design that addressed cost reduction and mass manufacturing by implementing a Design for Manufacturing (DFM) approach. The design changes also focused on reducing PowerBuoy Installation, Operation and Maintenance (IO&M) costs which are essential to reducing the overall cost of energy. In this design, changes to the core PowerBuoy technology were implemented to increase capability and reduce both CAPEX and OPEX costs. OPT conceptually envisaged moving from a floating structure to a seabed structure. The design change from a floating structure to seabed structure would provide the implementation of stroke‐ unlimited Power Take‐Off (PTO) which has a potential to provide significant power delivery improvement and transform the wave energy industry if proven feasible.

  17. Walden North Dam overtopping : emergency response and rehabilitation

    Energy Technology Data Exchange (ETDEWEB)

    Dyer, S. [FortisBC Inc., South Slocan, BC (Canada); McCreanor, J. [Acres International Ltd., Calgary, AB (Canada); Cronin, D.L.R.; Daw, D. [Acres International Ltd., Vancouver, BC (Canada)

    2004-09-01

    This paper described the events that led to the overtopping of the Walden North Dam during a heavy rainfall in June 2002, resulting in a breach around an abutment wall. The dam is part of a run-of-river hydro development on Cayoosh Creek near Lillooet, British Columbia. The Walden North Dam was a low, 46 meter wide concrete dam with a single radial gate. The dam overtopping was attributed to failure of the radial gate hoist. Prior to this event, the dam had been classified by the British Columbia Dam Safety Authorities as a high and then a low consequence category of failure. As facility managers, Aquila Networks Canada Ltd. established an immediate action plan to stabilize the situation and resume normal power production by applying the following priorities: (1) ensure safety of workers and the public, (2) limit further damage to the dam and other facilities, (3) ensure environmental protection, and (4) continue to operate the generation units. Local authorities were informed to evacuate a downstream campsite and environmental agencies were contacted along with safety regulators. Repairs included demolition of the damaged portion of the structure and construction a new two-bay gate/stoplog spillway and bridge. Construction was completed by September 2003 according to the requirements of the Department of Fisheries and Oceans for minimum flow, accurate control of fish flows and environmental monitoring of the stream area. 10 figs.

  18. Topological Magnonics: A Paradigm for Spin-Wave Manipulation and Device Design

    Science.gov (United States)

    Wang, X. S.; Zhang, H. W.; Wang, X. R.

    2018-02-01

    Conventional magnonic devices use magnetostatic waves whose properties are sensitive to device geometry and the details of magnetization structure, so the design and the scalability of the device or circuitry are difficult. We propose topological magnonics, in which topological exchange spin waves are used as information carriers, that do not suffer from conventional problems of magnonic devices with additional nice features of nanoscale wavelength and high frequency. We show that a perpendicularly magnetized ferromagnet on a honeycomb lattice is generically a topological magnetic material in the sense that topologically protected chiral edge spin waves exist in the band gap as long as a spin-orbit-induced nearest-neighbor pseudodipolar interaction (and/or a next-nearest-neighbor Dzyaloshinskii-Moriya interaction) is present. The edge spin waves propagate unidirectionally along sample edges and domain walls regardless of the system geometry and defects. As a proof of concept, spin-wave diodes, spin-wave beam splitters, and spin-wave interferometers are designed by using sample edges and domain walls to manipulate the propagation of topologically protected chiral spin waves. Since magnetic domain walls can be controlled by magnetic fields or electric current or fields, one can essentially draw, erase, and redraw different spin-wave devices and circuitry on the same magnetic plate so that the proposed devices are reconfigurable and tunable. The topological magnonics opens up an alternative direction towards a robust, reconfigurable and scalable spin-wave circuitry.

  19. Underwater Sound Levels at a Wave Energy Device Testing Facility in Falmouth Bay, UK.

    Science.gov (United States)

    Garrett, Joanne K; Witt, Matthew J; Johanning, Lars

    2016-01-01

    Passive acoustic monitoring devices were deployed at FaBTest in Falmouth Bay, UK, a marine renewable energy device testing facility during trials of a wave energy device. The area supports considerable commercial shipping and recreational boating along with diverse marine fauna. Noise monitoring occurred during (1) a baseline period, (2) installation activity, (3) the device in situ with inactive power status, and (4) the device in situ with active power status. This paper discusses the preliminary findings of the sound recording at FabTest during these different activity periods of a wave energy device trial.

  20. Experimental evaluation of the effect of wave focusing walls on the performance of the Sea-wave Slot-cone Generator

    International Nuclear Information System (INIS)

    Oliveira, P.; Taveira-Pinto, F.; Morais, T.; Rosa-Santos, P.

    2016-01-01

    Highlights: • The application of the Sea-wave Slot-cone Generator (SSG) in breakwaters is promising. • The use of wave focusing walls (WFW) improves the performance of the SSG technology. • The WFW concentrate the incident wave energy and increase the overtopping flow rates. • The design of new SSG devices should take into account the eventual use of WFW. • The use of WFW increased the annual energy production approximately to the double. - Abstract: The Sea-wave Slot-cone Generator (SSG) is a multi-level overtopping based wave energy converter that can be installed either nearshore or offshore. The installation in harbor breakwaters and in the shoreline presents several advantages despite the usual exposure to smaller waves than at offshore locations. This work analyzes the effect of wave focusing walls (i.e., wave concentrators) on the performance of isolated SSG units using a physical model built on a geometric scale of 1/40. Seven configurations were defined by changing the opening angle and the crest level of those elements. The use of wave concentrators proved to be advantageous since a wider wave front is captured and the run-up and overtopping phenomena are enhanced on the SSG ramp owing to the wave energy concentration (walls tapering effect). In fact, the total mean power captured increased for all SSG configurations with concentrators in comparison to the base configuration (without concentrators), regardless of the sea state considered. In terms of hydraulic performance, the gain associated to the use of wave concentrators depends on the characteristics of incident waves, being higher for the smaller significant wave heights and the shorter peak wave periods. The hydraulic efficiency, defined as the ratio between the total mean power captured per meter of SSG width and the wave power per meter width of the incident waves, increases with the significant wave height and reduces with the peak wave period in all tested SSG configurations. In

  1. Experimental investigation of fluvial dike breaching due to flow overtopping

    Science.gov (United States)

    El Kadi Abderrezzak, K.; Rifai, I.; Erpicum, S.; Archambeau, P.; Violeau, D.; Pirotton, M.; Dewals, B.

    2017-12-01

    The failure of fluvial dikes (levees) often leads to devastating floods that cause loss of life and damages to public infrastructure. Overtopping flows have been recognized as one of the most frequent cause of dike erosion and breaching. Fluvial dike breaching is different from frontal dike (embankments) breaching, because of specific geometry and boundary conditions. The current knowledge on the physical processes underpinning fluvial dike failure due to overtopping remains limited. In addition, there is a lack of a continuous monitoring of the 3D breach formation, limiting the analysis of the key mechanisms governing the breach development and the validation of conceptual or physically-based models. Laboratory tests on breach growth in homogeneous, non-cohesive sandy fluvial dikes due to flow overtopping have been performed. Two experimental setups have been constructed, permitting the investigation of various hydraulic and geometric parameters. Each experimental setup includes a main channel, separated from a floodplain by a dike. A rectangular initial notch is cut in the crest to initiate dike breaching. The breach development is monitored continuously using a specific developed laser profilometry technique. The observations have shown that the breach develops in two stages: first the breach deepens and widens with the breach centerline being gradually shifted toward the downstream side of the main channel. This behavior underlines the influence of the flow momentum component parallel to the dike crest. Second, the dike geometry upstream of the breach stops evolving and the breach widening continues only toward the downstream side of the main channel. The breach evolution has been found strongly affected by the flow conditions (i.e. inflow discharge in the main channel, downstream boundary condition) and floodplain confinement. The findings of this work shed light on key mechanisms of fluvial dike breaching, which differ substantially from those of dam

  2. Numerical and experimental investigation of wave dynamics on a land-fixed OWC device

    International Nuclear Information System (INIS)

    Ning, De-Zhi; Wang, Rong-Quan; Gou, Ying; Zhao, Ming; Teng, Bin

    2016-01-01

    An Oscillating Water Column (OWC) Wave Energy Converter (WEC) is a device that converts the energy of ocean waves to electrical energy. When an OWC is designed, both its energy efficiency and the wave loads on it should be considered. Most attentions have been paid to the energy efficiency of an OWC device in the past several decades. In the present study, the fully nonlinear numerical wave model developed by Ning et al. (2015) [1] is extended to simulate the dynamic wave forces on the land-fixed OWC device by using the acceleration potential method, and the experimental tests are also carried out. The comparisons between numerical results and experimental data are performed. Then the effects of wave conditions and chamber geometry on the wave force on the front wall of the chamber are investigated. The results indicate that the total wave force decreases with the increase of the wavelength and increases with the increase of the incident wave height. The wave force is also strongly influenced by the opening ratio, i.e., in the low-frequency region, the larger the opening ratio, the smaller the wave force and it shows an opposite tendency in the high-frequency region. - Highlights: • The wave dynamics on a land-fixed OWC device is numerically and experimentally studied. • The largest wave pressure occurs on the outside of the front wall on the free surface under the action of the wave crest. • The total horizontal wave load on the front wall decreases with the increase of the wavelength. • The opening ratio greatly influences the wave force on the front wall.

  3. Omnidirectional refractive devices for flexural waves based on graded phononic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Torrent, Daniel, E-mail: daniel.torrent@iemn.univ-lille1.fr; Pennec, Yan; Djafari-Rouhani, Bahram [Institut d' Electronique, de Microléctronique et de Nanotechnologie, UMR CNRS 8520, Université de Lille 1, 59655 Villeneuve d' Ascq (France)

    2014-12-14

    Different omnidirectional refractive devices for flexural waves in thin plates are proposed and numerically analyzed. Their realization is explained by means phononic crystal plates, where a previously developed homogenization theory is employed for the design of graded index refractive devices. These devices consist of a circular cluster of inclusions with a properly designed gradient in their radius. With this approach, the Luneburg and Maxwell lenses and a family of beam splitters for flexural waves are proposed and analyzed. Results show that these devices work properly in a broadband frequency region, being therefore an efficient approach for the design of refractive devices specially interesting for nano-scale applications.

  4. Wave and tidal generation devices reliability and availability

    CERN Document Server

    Tavner, Peter John

    2017-01-01

    To some extent the wave and tidal generation industry is following in the wake of the wind industry, learning from the growing experience of offshore wind farm deployment. This book combines wind industry lessons with wave and tidal field knowledge to explore the main reliability and availability issues facing this growing industry.

  5. Semiconductor Quantum Electron Wave Transport, Diffraction, and Interference: Analysis, Device, and Measurement.

    Science.gov (United States)

    Henderson, Gregory Newell

    Semiconductor device dimensions are rapidly approaching a fundamental limit where drift-diffusion equations and the depletion approximation are no longer valid. In this regime, quantum effects can dominate device response. To increase further device density and speed, new devices must be designed that use these phenomena to positive advantage. In addition, quantum effects provide opportunities for a new class of devices which can perform functions previously unattainable with "conventional" semiconductor devices. This thesis has described research in the analysis of electron wave effects in semiconductors and the development of methods for the design, fabrication, and characterization of quantum devices based on these effects. First, an exact set of quantitative analogies are presented which allow the use of well understood optical design and analysis tools for the development of electron wave semiconductor devices. Motivated by these analogies, methods are presented for modeling electron wave grating diffraction using both an exact rigorous coupled-wave analysis and approximate analyses which are useful for grating design. Example electron wave grating switch and multiplexer designs are presented. In analogy to thin-film optics, the design and analysis of electron wave Fabry-Perot interference filters are also discussed. An innovative technique has been developed for testing these (and other) electron wave structures using Ballistic Electron Emission Microscopy (BEEM). This technique uses a liquid-helium temperature scanning tunneling microscope (STM) to perform spectroscopy of the electron transmittance as a function of electron energy. Experimental results show that BEEM can resolve even weak quantum effects, such as the reflectivity of a single interface between materials. Finally, methods are discussed for incorporating asymmetric electron wave Fabry-Perot filters into optoelectronic devices. Theoretical and experimental results show that such structures could

  6. Efficiency of a gyroscopic device for conversion of mechanical wave energy to electrical energy

    DEFF Research Database (Denmark)

    Carlsen, Martin; Darula, Radoslav; Gravesen, Jens

    2011-01-01

    We consider a recently proposed gyroscopic device for conversion of mechanical ocean wave energy to electrical energy. Two models of the device derived from standard engineering mechanics from the literature are analysed, and a model is derived from analytical mechanics considerations. From...... these models, estimates of the power production, eciency, forces and moments are made. We nd that it is possible to extract a signicant amount of energy from an ocean wave using the described device. Further studies are required for a full treatment of the device....

  7. A Wave Power Device with Pendulum Based on Ocean Monitoring Buoy

    Science.gov (United States)

    Chai, Hui; Guan, Wanchun; Wan, Xiaozheng; Li, Xuanqun; Zhao, Qiang; Liu, Shixuan

    2018-01-01

    The ocean monitoring buoy usually exploits solar energy for power supply. In order to improve power supply capacity, this paper proposes a wave power device according to the structure and moving character of buoy. The wave power device composes of pendulum mechanism that converts wave energy into mechanical energy and energy storage mechanism where the mechanical energy is transferred quantitatively to generator. The hydrodynamic equation for the motion of buoy system with generator devise is established based on the potential flow theory, and then the characteristics of pendulum motion and energy conversion properties are analysed. The results of this research show that the proposed wave power devise is able to efficiently and periodically convert wave energy into power, and increasing the stiffness of energy storage spring is benefit for enhancing the power supply capacity of the buoy. This study provides a theory reference for the development of technology on wave power generator for ocean monitoring buoy.

  8. Pneumatic Performance of a Non-Axisymmetric Floating Oscillating Water Column Wave Energy Conversion Device in Random Waves

    OpenAIRE

    Bull, Diana

    2014-01-01

    A stochastic approach is used to gain a sophisticated understanding of a non-axisymmetric floating oscillating water column's response to random waves. A linear, frequency-domain performance model that links the oscillating structure to air-pressure fluctuations with a Wells Turbine in 3-dimensions is used to study the device performance at a northern California deployment location. Both short-term, sea-state, and long-term, annual, predictions are made regarding the devices performance. U...

  9. Determination of Wave Model Uncertainties used for Probabilistic Reliability Assessments of Wave Energy Devices

    DEFF Research Database (Denmark)

    Ambühl, Simon; Kofoed, Jens Peter; Sørensen, John Dalsgaard

    2014-01-01

    Wave models used for site assessments are subject to model uncertainties, which need to be quantified when using wave model results for probabilistic reliability assessments. This paper focuses on determination of wave model uncertainties. Considered are four different wave models and validation...... data is collected from published scientific research. The bias, the root-mean-square error as well as the scatter index are considered for the significant wave height as well as the mean zero-crossing wave period. Based on an illustrative generic example it is shown how the estimated uncertainties can...... be implemented in probabilistic reliability assessments....

  10. Characterisation of the biofouling community on a floating wave energy device.

    Science.gov (United States)

    Nall, Christopher R; Schläppy, Marie-Lise; Guerin, Andrew J

    2017-05-01

    Wave energy devices are novel structures in the marine environment and, as such, provide a unique habitat for biofouling organisms. In this study, destructive scrape samples and photoquadrats were used to characterise the temperate epibenthic community present on prototypes of the Pelamis wave energy converter. The biofouling observed was extensive and diverse with 115 taxa recorded including four non-native species. Vertical zonation was identified on the sides of the device, with an algae-dominated shallow subtidal area and a deeper area characterised by a high proportion of suspension-feeding invertebrates. Differences in species composition and biomass were also observed between devices, along the length of the device and between sampling dates. This research provides an insight into the variation of biofouling assemblages on a wave energy device as well as the potential technical and ecological implications associated with biofouling on marine renewable energy structures.

  11. Vector wave diffraction pattern of slits masked by polarizing devices

    Indian Academy of Sciences (India)

    This calls for a systematic study of diffraction properties of different apertures using polarization-sensitive devices. In the present paper, we have studied the Fraunhofer diffraction pattern of slits masked by different kinds of polarizing devices which introduce a phase difference between the two orthogonal components of the ...

  12. Surface ionization wave in a plasma focus-like model device

    International Nuclear Information System (INIS)

    Yordanov, V; Blagoev, A; Ivanova-Stanik, I; Veldhuizen, E M van; Nijdam, S; Dijk, J van; Mullen, J J A M van der

    2008-01-01

    A numerical particle in cell-Monte Carlo model of the breakdown in the plasma focus device simulates the development of an ionization wave sliding along the insulator. In order to validate this model a planar model device is created. The pictures of the discharges taken by a fast optical camera show that we have qualitative agreement between the model and the experimental observations.

  13. Surface ionization wave in a plasma focus-like model device

    Energy Technology Data Exchange (ETDEWEB)

    Yordanov, V; Blagoev, A [Faculty of Physics, University of Sofia, 5 James Bourchier Blvd, BG-1164, Sofia (Bulgaria); Ivanova-Stanik, I [IPPLM, 23 Hery St, PO Box 49, PL-00-908 Warsaw (Poland); Veldhuizen, E M van; Nijdam, S; Dijk, J van; Mullen, J J A M van der [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)], E-mail: v.yordanov@phys.uni-sofia.bg

    2008-11-07

    A numerical particle in cell-Monte Carlo model of the breakdown in the plasma focus device simulates the development of an ionization wave sliding along the insulator. In order to validate this model a planar model device is created. The pictures of the discharges taken by a fast optical camera show that we have qualitative agreement between the model and the experimental observations.

  14. Floating attenuator wave energy device. Wavegen HYDRA project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The Wavegen Project which set out to develop a floating externally tensioned articulated wave-energy generator based on work carried out at RMCS Shrivenham in the 1980s has been abandoned until further notice. The computer modelling carried out in the early days indicated much promise, but the promise turned to disappointment when difficulties cropped-up in attempting to put the design into practice. A particular problem arose in matching the external tension to an equivalent beam stiffness to tune the natural bending frequency of the raft to that of the driving waves. A further eleven practical problems encountered are discussed.

  15. Design of Passive Acoustic Wave Shaping Devices and Their Experimental Validation

    DEFF Research Database (Denmark)

    Christiansen, Rasmus Ellebæk; Sigmund, Ole; Fernandez Grande, Efren

    We discuss a topology optimization based approach for designing passive acoustic wave shaping devices and demonstrate its application to; directional sound emission [1], sound focusing and wave splitting. Optimized devices, numerical and experimental results are presented and benchmarked against...... other designs proposed in the literature. We focus on design problems where the size of the device is on the order of the wavelength, a problematic region for traditional design methods, such as ray tracing.The acoustic optimization problem is formulated in the frequency domain and modeled...

  16. Review of 3D Printed Millimeter-Wave and Terahertz Passive Devices

    Directory of Open Access Journals (Sweden)

    Bing Zhang

    2017-01-01

    Full Text Available The 3D printing technology is catching attention nowadays. It has certain advantages over the traditional fabrication processes. We give a chronical review of the 3D printing technology from the time it was invented. This technology has also been used to fabricate millimeter-wave (mmWave and terahertz (THz passive devices. Though promising results have been demonstrated, the challenge lies in the fabrication tolerance improvement such as dimensional tolerance and surface roughness. We propose the design methodology of high order device to circumvent the dimensional tolerance and suggest specific modelling of the surface roughness of 3D printed devices. It is believed that, with the improvement of the 3D printing technology and related subjects in material science and mechanical engineering, the 3D printing technology will become mainstream for mmWave and THz passive device fabrication.

  17. Quasi-static analysis of wave loadings on spine-based wave energy devices

    Energy Technology Data Exchange (ETDEWEB)

    Lockett, F.P.; Peatfield, A.M.; West, M.J.

    1980-02-01

    A report is given on the Wave Energy Research Programme at Lanchester Polytechnic. Results are presented for both theoretical and experimental scale models for wave loadings on circular and rectangular spines of various lengths. The results are in good agreement over the operational wave range for the 1/50 scale model and for the more limited data on the 1/10 scale model.

  18. THz Wave Propagation on Strip Lines: Devices, Properties, and Applications

    Directory of Open Access Journals (Sweden)

    Y. Kadoya

    2008-06-01

    Full Text Available We report the propagation characteristics of THz pulses on micro-strip-lines and coplanar strip-lines, in which low permittivity polymer materials are used as the dielectric layer or the substrate. As a result of the low attenuation and small dispersion in the devices, the spectral width up to 3 THz can be achieved even after the 1 mm propagation. Spectroscopic characterizations of liquid or powder specimens are demonstrated using the devices. We also show a possibility of realizing a very low attenuation using a quadrupole mode in three strip coplanar lines on the polymer substrate.

  19. Wave Forces on Crown Walls

    DEFF Research Database (Denmark)

    Pedersen, Jan; Burcharth, H. F.

    1993-01-01

    This paper presents some of the results from a large parametric laboratory study including more than 200 long-duration model tests. The study addresses both the wave forces imposed on the breakwater crown wall as well as the performance of the structure in reducing the wave overtopping. The testing...

  20. Near-surface viscosity measurements with a love acoustic wave device

    International Nuclear Information System (INIS)

    Collings, A.F.; Cooper, B.J.; Lappas, S.; Sor, J.A.

    1999-01-01

    Full text: In the last decade, considerable research effort has been directed towards interfacing piezoelectric transducers with biological detection systems to produce efficient and highly selective biosensors. Several types of piezoelectric or, more specifically, acoustic wave transducers have been investigated. Our group has developed Love wave (guided surface skimming wave) devices which are made by attaching a thin overlayer with the appropriate acoustic properties to the surface of a conventional surface horizontal mode device. An optimised layer concentrates most of the propagating wave energy in the guiding layer and can improve the device sensitivity in detecting gas-phase mass loading on the surface some 20- to 40-fold. Love wave devices used in liquid phase sensing will also respond to viscous, as well as mass, loading on the device surface. We have studied the propagation of viscous waves into liquid sitting on a Love wave device both theoretically and experimentally. Modelling of the effect of a viscous liquid layer on a Love wave propagating in a layered medium predicts the velocity profile in the solid substrate and in the adjoining liquid. This is a function of the thickness of the guiding layer, the elastic properties of the guiding layer and the piezoelectric substrate, and of the viscosity and density of the liquid layer. We report here on measurements of the viscosity of aqueous glycerine solutions made with a quartz Love wave device with a 5.5 μm SiO 2 guiding layer. The linear relationship between the decrease in the device frequency and the square root of the viscosity density product is accurately observed at Newtonian viscosities. At higher viscosities, there is an increase in damping, the insertion loss of the device saturates, Δf is no longer proportional to (ηp) l/2 and reaches a maximum. We also show results for the determination of the gelation time in protein and inorganic aqueous gels and for the rate of change of viscosity with

  1. Applications of Shock Wave Research to Developments of Therapeutic Devices.

    Science.gov (United States)

    Takayama, Kazuyoshi

    2007-06-01

    Underwater shock wave research applied to medicine started in 1980 by exploding micro lead azide pellets in water. Collaboration with urologists in the School of Medicine, Tohoku University at the same time was directed to disintegration of kidney stones by controlling shock waves. We initially proposed a miniature truncated ellipsoidal cavity for generating high-pressures enough to disintegrate the stone but gave up the idea, when encountering the Dornie Systems' invention of an extracorporeal shock wave lithotripter (ESWL). Then we confirmed its effectiveness by using 10 mg silver azide pellets and constructed our own lithotripter, which was officially approved for a clinical use in 1987. Tissue damage during ESWL was attributable to bubble collapse and we convinced it could be done in a controlled fashion. In 1996, we used 160 mJ pulsed Ho:YAG laser beam focusing inside a catheter for shock generation and applied it to the revascularization of cerebral embolism, which is recently expanded to the treatment of pulmonary infarction. Micro water jets discharged in air were so effective to dissect soft tissues preserving small blood vessels. Animal experiments are successfully performed with high frequency water jets driven by an actuator-assisted micro-pump. A metal foil is deformed at high speed by a Q-switched Nd:YAG laser beam loading. We used this technique to project micro-particles or dry drugs attached on its reverse side and extended it to a laser ablation assisted dry drug delivery or DNA introductory system.

  2. Prototype Testing of the Wave Energy Converter Wave Dragon

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter; Friis-Madsen, Erik

    2006-01-01

    The Wave Dragon is an offshore wave energy converter of the overtopping type. It consists of two wave reflectors focusing the incoming waves towards a ramp, a reservoir for collecting the overtopping water and a number of hydro turbines for converting the pressure head into power. In the period...... from 1998 to 2001 extensive wave tank testing on a scale model was carried at Aalborg University. Then, a 57!27 m wide and 237 tonnes heavy (incl. ballast) prototype of the Wave Dragon, placed in Nissum Bredning, Denmark, was grid connected in May 2003 as the world’s first offshore wave energy...... converter. The prototype is fully equipped with hydro turbines and automatic control systems, and is instrumented in order to monitor power production, wave climate, forces in mooring lines, stresses in the structure and movements of the Wave Dragon. In the period May 2003 to January 2005 an extensive...

  3. Prototype Testing of the Wave Energy Converter Wave Dragon

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter Bak; Friis-Madsen, Erik

    2004-01-01

    The Wave Dragon is an offshore wave energy converter of the overtopping type. It consists of two wave reflectors focusing the incoming waves towards a ramp, a reservoir for collecting the overtopping water and a number of hydro turbines for converting the pressure head into power. In the period...... from 1998 to 2001 extensive wave tank testing on a scale model was carried at Aalborg University. Then, a 57 x 27 m wide and 237 tonnes heavy (incl. ballast) prototype of the Wave Dragon, placed in Nissum Bredning, Denmark, was grid connected in May 2003 as the world's first offshore wave energy...... converter. The prototype is fully equipped with hydro turbines and automatic control systems, and is instrumented in order to monitor power production, wave climate, forces in mooring lines, stresses in the structure and movements of the Wave Dragon. During the last months, extensive testing has started...

  4. Effect of environment on the propagation of electromagnetic waves in GRC 408E digital radiorelay devices

    Directory of Open Access Journals (Sweden)

    Vojkan M. Radonjić

    2011-01-01

    Full Text Available Quality transmission of digital signals from a transmitting radio-relay device to a receiving one depends on the impact of environmental effects on the propagation of electromagnetic waves. In this paper some of the most important effects are explained and modeled, especially those characteristic for the frequency range within which the GRC 408E operates. The modeling resulted in the conclusions about the quality of transmission of digital signals in the GRC 408E radio-relay equipment. Propagation of electromagnetic waves A radio-relay link is achieved by direct electromagnetic waves, provided there is a line of sight between the transmitting and receiving antenna of a radio-relay device. Electromagnetic waves on the road are exposed to various environmental influences causing phenomena such as bending, reflection, refraction, absorption and multiple propagation. Due to these environmental effects, the quality of information transmission is not satisfactory and a radio-relay link is not reliable. The approach to the analysis of the quality of links in digital radiorelay devices is different from the one in analog radio-relay devices. Therefore, the quality is seen through errors in the received bit ( BER , the propagation conditions are taken into account, a reservation for the fading is determined by other means, etc.. Phenomena which accompany the propagation of electromagnetic waves in digital radio-relay links The propagation of direct EM waves is followed by the following phenomena: - attenuation due to propagation, - diffraction (changing table, - refraction (refraction, - reflection (refusing, - absorption (absorption and - multiple wave propagation. Each of these has a negative effect on the quality of the received signal at the receiving antenna of the radio-relay device. Attenuation due to propagation of electromagnetic waves The main parameter for evaluating the quality of radio-relay links is the level of the field at the reception

  5. High-resolution marine flood modelling coupling overflow and overtopping processes: framing the hazard based on historical and statistical approaches

    Science.gov (United States)

    Nicolae Lerma, Alexandre; Bulteau, Thomas; Elineau, Sylvain; Paris, François; Durand, Paul; Anselme, Brice; Pedreros, Rodrigo

    2018-01-01

    A modelling chain was implemented in order to propose a realistic appraisal of the risk in coastal areas affected by overflowing as well as overtopping processes. Simulations are performed through a nested downscaling strategy from regional to local scale at high spatial resolution with explicit buildings, urban structures such as sea front walls and hydraulic structures liable to affect the propagation of water in urban areas. Validation of the model performance is based on hard and soft available data analysis and conversion of qualitative to quantitative information to reconstruct the area affected by flooding and the succession of events during two recent storms. Two joint probability approaches (joint exceedance contour and environmental contour) are used to define 100-year offshore conditions scenarios and to investigate the flood response to each scenario in terms of (1) maximum spatial extent of flooded areas, (2) volumes of water propagation inland and (3) water level in flooded areas. Scenarios of sea level rise are also considered in order to evaluate the potential hazard evolution. Our simulations show that for a maximising 100-year hazard scenario, for the municipality as a whole, 38 % of the affected zones are prone to overflow flooding and 62 % to flooding by propagation of overtopping water volume along the seafront. Results also reveal that for the two kinds of statistic scenarios a difference of about 5 % in the forcing conditions (water level, wave height and period) can produce significant differences in terms of flooding like +13.5 % of water volumes propagating inland or +11.3 % of affected surfaces. In some areas, flood response appears to be very sensitive to the chosen scenario with differences of 0.3 to 0.5 m in water level. The developed approach enables one to frame the 100-year hazard and to characterize spatially the robustness or the uncertainty over the results. Considering a 100-year scenario with mean sea level rise (0.6 m), hazard

  6. The wave vane - A device to measure the breaker angle

    Digital Repository Service at National Institute of Oceanography (India)

    Chandramohan, P.; Nayak, B.U.; Anand, N.M.

    directional wave gauge at a considerable cost. For economic and practical considerations, visual measurements on the breaker height, the breaker period and the breaker angle are generally made in the LEO pro- gramme. The breaker height is recorded... of the fins. Flag masts are fixed on either end of the arms. The whole assembly thus revolves around the spindle resting on the sleeve. WORKING PRINCIPLE The flag masts, two on the revolving arms and one on the top of the spindle lie always in a straight...

  7. Radiological hazard assessment of extracorporeal shock wave lithotripsy devices

    International Nuclear Information System (INIS)

    Sprague, D.D.; Vermeere, W.R.

    1987-01-01

    With the recent introduction of ESWL to the clinical environment, a new health physics challenge has entered the medical consulting area. The x-ray imaging systems used in the devices are of a conventional design, but in an unusual configuration that is difficult to properly assess. The scope of this paper considers specific evaluation problems, and deals with methods developed during experience with 4 units in California. Pertinent regulations are also covered, along with a synopsis of data obtained and ALARA recommendations

  8. Measurement of Underwater Operational Noise Emitted by Wave and Tidal Stream Energy Devices.

    Science.gov (United States)

    Lepper, Paul A; Robinson, Stephen P

    2016-01-01

    The increasing international growth in the development of marine and freshwater wave and tidal energy harvesting systems has been followed by a growing requirement to understand any associated underwater impact. Radiated noise generated during operation is dependent on the device's physical properties, the sound-propagation environment, and the device's operational state. Physical properties may include size, distribution in the water column, and mechanics/hydrodynamics. The sound-propagation environment may be influenced by water depth, bathymetry, sediment type, and water column acoustic properties, and operational state may be influenced by tidal cycle and wave height among others This paper discusses some of the challenges for measurement of noise characteristics from these devices as well as a case study of the measurement of radiated noise from a full-scale wave energy converter.

  9. Reliability and Maintenance for Offshore Wind Turbines and Wave Energy Devices

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2015-01-01

    Wind turbines are in some countries contributing significantly the production of electricity and wave energy devices have the potential to be developed in a similarway. For both offshore wind turbines and wave energy devices reliability is a key issue since costs to operation and maintenance may...... be significant contributors to the Levelized Cost Of Energy and OM costs are highly dependent on the reliability of the components implying that it is important to focus on increasing the reliability as much as is economically reasonable. This paper describes basic aspects for reliability analysis of wind...... turbines and wave energy devices with special focus on structural components. The reliability assessment needs include the effects of the control system and possible faults due to failure of electrical/mechanical components and e.g. loss of grid connection. The target reliability level for wind turbine...

  10. Contactless remote induction of shear waves in soft tissues using a transcranial magnetic stimulation device

    International Nuclear Information System (INIS)

    Grasland-Mongrain, Pol; Miller-Jolicoeur, Erika; Cloutier, Guy; Tang, An; Catheline, Stefan

    2016-01-01

    This study presents the first observation of shear waves induced remotely within soft tissues. It was performed through the combination of a transcranial magnetic stimulation device and a permanent magnet. A physical model based on Maxwell and Navier equations was developed. Experiments were performed on a cryogel phantom and a chicken breast sample. Using an ultrafast ultrasound scanner, shear waves of respective amplitudes of 5 and 0.5 μm were observed. Experimental and numerical results were in good agreement. This study constitutes the framework of an alternative shear wave elastography method. (paper)

  11. Contactless remote induction of shear waves in soft tissues using a transcranial magnetic stimulation device

    Science.gov (United States)

    Grasland-Mongrain, Pol; Miller-Jolicoeur, Erika; Tang, An; Catheline, Stefan; Cloutier, Guy

    2016-03-01

    This study presents the first observation of shear waves induced remotely within soft tissues. It was performed through the combination of a transcranial magnetic stimulation device and a permanent magnet. A physical model based on Maxwell and Navier equations was developed. Experiments were performed on a cryogel phantom and a chicken breast sample. Using an ultrafast ultrasound scanner, shear waves of respective amplitudes of 5 and 0.5 μm were observed. Experimental and numerical results were in good agreement. This study constitutes the framework of an alternative shear wave elastography method.

  12. Research status of wave energy conversion (WEC) device of raft structure

    Science.gov (United States)

    Dong, Jianguo; Gao, Jingwei; Tao, Liang; Zheng, Peng

    2017-10-01

    This paper has briefly described the concept of wave energy generation and six typical conversion devices. As for raft structure, detailed analysis is provided from its development process to typical devices. Taking the design process and working principle of Plamis as an example, the general principle of raft structure is briefly described. After that, a variety of raft structure models are introduced. Finally, the advantages and disadvantages, and development trend of raft structure are pointed out.

  13. Brain Computer Interface-Controlling Devices Utilizing The Alpha Brain Waves

    Directory of Open Access Journals (Sweden)

    Rohan Hundia

    2015-01-01

    Full Text Available Abstract This paper describes the development and testing of an interface system whereby one can control external devices by voluntarily controlling alpha waves that is through eye movement. Such a system may be used for the control of prosthetics robotic arms and external devices like wheelchairs using the alpha brain waves and the Mu rhythm. The response generated through the movement of the eye detecting and controlling the amplitude of the alpha brain waves is interfaced and processed to control Robotic systems and smart home control. In order to measure the response of alpha waves over different lobes of the brain initially I measured these signals over 32 regions using silver chloride plated electrodes. By the opening and the closure of the eyes and the movement in the up-down left-right directions and processing these movements measuring them over the occipital region I was able to differentiate the amplitude of the alpha waves generated due to these several movements. In the First session testing period subjects were asked to close and open their eyes and they were able to control limited movements of a Robot and a prosthetic arm. In the Second 2session the movement of the eyes was also considered left-right up-down along with the opening and closure during this time span they were able to control more dimensions of the robot several devices at the same time using different eye movements.

  14. A surface-integral-equation approach to the propagation of waves in EBG-based devices

    NARCIS (Netherlands)

    Lancellotti, V.; Tijhuis, A.G.

    2012-01-01

    We combine surface integral equations with domain decomposition to formulate and (numerically) solve the problem of electromagnetic (EM) wave propagation inside finite-sized structures. The approach is of interest for (but not limited to) the analysis of devices based on the phenomenon of

  15. Development of Wave Energy Devices: The Danish Case / The Dragon of Nissum Bredning

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter

    2009-01-01

    The paper presents the Danish case of development of wave energy devices and outlines the established best practice. A brief overview of international standardization efforts is given and the Danish involvement in this described. The developed Danish best practice, which is being carried over to ...

  16. Continuous wave terahertz radiation from an InAs/GaAs quantum-dot photomixer device

    Science.gov (United States)

    Kruczek, T.; Leyman, R.; Carnegie, D.; Bazieva, N.; Erbert, G.; Schulz, S.; Reardon, C.; Reynolds, S.; Rafailov, E. U.

    2012-08-01

    Generation of continuous wave radiation at terahertz (THz) frequencies from a heterodyne source based on quantum-dot (QD) semiconductor materials is reported. The source comprises an active region characterised by multiple alternating photoconductive and QD carrier trapping layers and is pumped by two infrared optical signals with slightly offset wavelengths, allowing photoconductive device switching at the signals' difference frequency ˜1 THz.

  17. ZnO film for application in surface acoustic wave device

    International Nuclear Information System (INIS)

    Du, X Y; Fu, Y Q; Tan, S C; Luo, J K; Flewitt, A J; Maeng, S; Kim, S H; Choi, Y J; Lee, D S; Park, N M; Park, J; Milne, W I

    2007-01-01

    High quality, c-axis oriented zinc oxide (ZnO) thin films were grown on silicon substrate using RF magnetron sputtering. Surface acoustic wave (SAW) devices were fabricated with different thickness of ZnO ranging from 1.2 to 5.5 μmUm and the frequency responses were characterized using a network analyzer. Thick ZnO films produce the strongest transmission and reflection signals from the SAW devices. The SAW propagation velocity is also strongly dependent on ZnO film thickness. The performance of the ZnO SAW devices could be improved with addition of a SiO 2 layer, in name of reflection signal amplitude and phase velocity of Rayleigh wave

  18. A Numerical Analysis of Phononic-Assisted Control of Ultrasound Waves in Acoustofluidic Device

    DEFF Research Database (Denmark)

    Moiseyenko, Rayisa; Bruus, Henrik

    2015-01-01

    and streaming has received much attention, since it relies solely on mechanical properties such as particle size and contrast in density and compressibility. We present a theoretical study of phononic-assisted control of ultrasound waves in acoustofluidic devices. We propose the use of phononic crystal...... diffractors, which can be introduced in acoustofluidic structures. These diffractors can be applied in the design of efficient resonant cavities, directional sound waves for new types of particle sorting methods, or acoustically controlled deterministic lateral displacement. The PnC-diffractor-based devices...... can be made configurable, by embedding the diffractors, all working at the same excitation frequency but with different resulting diffraction patterns, in exchangeable membranes on top of the device....

  19. Scale Effects Related to Small Physical Modelling of Overtopping of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke

    2007-01-01

    to avoid damage to the breakwater itself and to objects located behind the breakwater. Extreme overtopping events result in water and spray thrown over the crest with considerable velocities. These events can be extremely dangerous as people, cars and even trains have been washed into the sea. Buildings...

  20. WaveSAX device: design optimization through scale modelling and a PTO strategical control system

    Science.gov (United States)

    Peviani, Maximo; Danelli, Andrea; Dadone, Gianluca; Dalmasso, Alberto

    2017-04-01

    WaveSAX is an innovative OWC (Oscillating Water Column) device for the generation of electricity from wave power, conceived to be installed in coastal marine structures, such as ports and harbours. The device - especially designed for the typical wave climate of Mediterranean Sea - is characterized by two important aspects: flexibility to fit in different structural configurations and replication in a large number of units. A model of the WaveSAX device on a scale 1:5 has been built and tested in the ocean tank at Ecole Centrale de Nantes (France). The study aimed to analyse the behaviour of the device, including two Wells turbine configurations (with three and four blades), with regular and irregular wave conditions in the ocean wave tank. The model and the wave basin were equipped with a series of sensors which allowed to measure the following parameters during the tests: pressure in different points inside the device, the free water surface displacement inside and outside the device, the rotational velocity and the torque at the top of the axis. The tests had the objective to optimize the device design, especially as far as the characteristics of the rotor of the turbine is concern. Although the performance of the WaveSAX has been satisfactory for regular wave conditions, the behaviour of the Wells turbines for irregular wave climate has shown limitations in terms of maintaining the capacity to transform hydraulics energy into mechanical power. To optimize the efficiency of the turbine, an electronical system has been built on the basis of the ocean tank tests. It allows to continuously monitor and command the rotational speed and the torque of the rotor connected with the turbine, and to control in real time the electrical flow of a motor-generator, either absorbing energy as a generator, or providing power to the turbine working as an engine. Two strategies - based on the velocity and the torque control - have been investigate in the electronic test bench

  1. On the Fundamental Mode Love Wave in Devices Incorporating Thick Viscoelastic Layers

    International Nuclear Information System (INIS)

    Liu Jian-Sheng; Wang Li-Jun; He Shi-Tang

    2015-01-01

    A detailed investigation is presented for Love waves (LWs) with thick viscoelastic guiding layers. A theoretical calculation and an experiment are carried out for LW devices incorporating an SU-8 guiding layer, an ST-90° X quartz substrate and two 28-μm periodic interdigital transducers. Both the calculated and the measured results show an increase in propagation velocity when h/λ > 0.05. The measured insertion loss of LWs is consistent with the calculated propagation loss. The insertion loss of bulk waves is also measured and is compared with that of LWs. (paper)

  2. Estimation of wave conditions at Liseleje location

    DEFF Research Database (Denmark)

    Borgarino, Bruno; Brorsen, Michael

    This report present the near-shore waves conditions at Liseleje. This study has been carried out as a first step to evaluate the possibility of installing an overtopping wave energy converter at Liseleje. The offshore conditions have first been calculated, using 30 years recorded wind data. Then ...

  3. Development of the Wave Energy Converter

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter; Sørensen, Hans Christian

    2000-01-01

    The development of the wave energy converter Wave Dragon (WD) is presented. The WD is based on the overtopping principle. Initially a description of the WD is given. Then the development over time in terms of the various research and development projects working with the concept is described. Thi...

  4. Shock wave effects in copper: Design of an experimental device for post recovery mechanical testing

    International Nuclear Information System (INIS)

    Buy, Francois; Llorca, Fabrice

    2002-01-01

    The mechanical behavior of metals may prove high changes with strain rate and pressure loading history. In order to investigate the effect of a shock on the ulterior mechanical behavior of high purity copper, we set up an experimental device inspired from G. T. Gray III's works. This device, based on the trapping of shock waves after a plane plate impact is validated by numerical simulations. The aim of these simulations is the evaluation of the heterogeneity of plastic deformation. Shock pressures up to 10 GPa have been investigated. The plastic strain levels subsequent to the shock are between 0.08 and 0.15 in the sample

  5. AlScN thin film based surface acoustic wave devices with enhanced microfluidic performance

    OpenAIRE

    Wang, Wenbo; Fu, Yong Qing; Chen, Jinju; Xuan, Weipeng; Chen, Jinkai; Mayrhofer, Paul; Duan, Pengfei; Bittner, Elmar; Luo, Jikui

    2016-01-01

    This paper reports the characterization of scandium aluminum nitride (Al1−x Sc x N, x  =  27%) films and discusses surface acoustic wave (SAW) devices based on them. Both AlScN and AlN films were deposited on silicon by sputtering and possessed columnar microstructures with (0 0 0 2) crystal orientation. The AlScN/Si SAW devices showed improved electromechanical coupling coefficients (K 2, ~2%) compared with pure AlN films (

  6. Numerical and tank test of a pivoted floating device for wave energy

    International Nuclear Information System (INIS)

    Coiro, Domenico P.; Calise, Giuseppe; Bizzarrini, Nadia; Troise, Giancarlo

    2015-01-01

    In this paper a system for extracting energy from waves is presented. The present work deals with numerical and experimental tests on a scaled model, performed in the DII towing tank facility. The device is made up of a floating body, which oscillates due to waves, and of a linear electromechanical generator. The electromechanical generator, based on ball-bearing screw, is linked both to the buoyant body and a fixed frame, converting relative movements of its anchor point in electrical power. Numerical analyses on such device have been performed in order to evaluate critical parameters for the system optimization, including analytical study of the system, potential flow and computational fluid dynamics (CFD) simulations, based on Reynolds Averaged Navier-Stokes (RANS), as well. [it

  7. Re-thinking Reading in the Context of a New Wave of Electronic Reading Devices

    Science.gov (United States)

    Kratky, Andreas

    We are currently witnessing a new wave of digital reading devices that will probably significantly change the way we read and publish. This is not the first digital revolution of aspects of cultural production and perception. This paper compares the previous digital revolutions of the music, film and publishing industries and attempts a prognosis of coming changes in the way we will work with digital texts. As a conclusion a new notion of interface design for the emerging reading ecology is proposed.

  8. Compact toroidal energy storage device with relativistically densified electrons through the use of travelling magnetic waves

    International Nuclear Information System (INIS)

    Peter, W.; Faehl, R.J.

    1983-01-01

    A new concept for a small compact multimegajoule energy storage device utilizing relativistically densified electron beam circulating in a torus is presented. The electron cloud is produced through inductive charge injection by a travelling magnetic wave circulating the torus. Parameters are given for two representative toroidal energy storage devices, consisting of 1 m and 32 m in radius respectively, which could store more than 4 x 10 17 electrons and 30' MJ in energy. The concept utilizes the idea that large electric and magnetic fields can be produced by a partially space-charge neutralized intense relativistic electron beam which could become many orders of magnitude greater than the externally applied field confining the beam. In the present approach, the electron cloud densification can be achieved gradually by permitting multiple traversals of the magnetic wave around the torus. The magnetic mirror force acts on the orbital magnetic electron dipole moment and completely penetrates the entire electron cloud. As the electrons gain relativistic energies, the beam can be continuously densified at the front of the travelling wave, where the magnetic field is rising with time. The use of travelling magnetic wave to accelerate an electron cloud and the use of large electric field at the thusly accelerated cloud form the basis for a high beam intensity and hence high energy storage. Technical considerations and several potential applications, which include the driving of a powerful gyrotron, are discussed

  9. Anti-miss-shot control device for selective stone disintegration in extracorporeal shock wave lithotripsy

    Science.gov (United States)

    Kuwahara, M.; Ioritani, N.; Kambe, K.; Orikasa, S.; Takayama, K.

    1991-06-01

    A new device to prevent erroneously focused shock waves to the renal parenchyma during extracorporeal shock wave lithotripsy (ESWL) has been developed; an anti-miss-shot control device (AMCD) and experiments have been conducted to evaluate its effectiveness. For shock wave generation and stone localization, piezoceramic elements (PSE) and ultrasound localization, respectively were used. After stone localization, probing ultrasounds (PU) were emmitted from the PSE towards the focal region and the reflected sound levels (RSL) were monitored by the PSE which also functioned as a microphone. A direct hit by the PU to the stone or a miss was judged from the RSL, i.e. a high RSL indicates a direct hit and a low RSL indicates a miss. Shock waves were generated only when the RSL exceeded the level which indicated a direct hit. The experimental results showed that the injury to the renal parenchyma was decreased by using the AMCD. Clinical application of the AMCD is expected to increase the safety of ESWL.

  10. Voltage-Controlled Reconfigurable Spin-Wave Nanochannels and Logic Devices

    Science.gov (United States)

    Rana, Bivas; Otani, YoshiChika

    2018-01-01

    Propagating spin waves (SWs) promise to be a potential information carrier in future spintronics devices with lower power consumption. Here, we propose reconfigurable nanochannels (NCs) generated by voltage-controlled magnetic anisotropy (VCMA) in an ultrathin ferromagnetic waveguide for SW propagation. Numerical micromagnetic simulations are performed to demonstrate the confinement of magnetostatic forward volumelike spin waves in NCs by VCMA. We demonstrate that the NCs, with a width down to a few tens of a nanometer, can be configured either into a straight or curved structure on an extended SW waveguide. The key advantage is that either a single NC or any combination of a number of NCs can be easily configured by VCMA for simultaneous propagation of SWs either with the same or different wave vectors according to our needs. Furthermore, we demonstrate the logic operation of a voltage-controlled magnonic xnor and universal nand gate and propose a voltage-controlled reconfigurable SW switch for the development of a multiplexer and demultiplexer. We find that the NCs and logic devices can even be functioning in the absence of the external-bias magnetic field. These results are a step towards the development of all-voltage-controlled magnonic devices with an ultralow power consumption.

  11. Novel device (AirWave) to assess endotracheal tube migration: a pilot study.

    Science.gov (United States)

    Nacheli, Gustavo Cumbo; Sharma, Manish; Wang, Xiaofeng; Gupta, Amit; Guzman, Jorge A; Tonelli, Adriano R

    2013-08-01

    Little is known about endotracheal tube (ETT) migration during routine care among critically ill patients. AirWave is a novel device that uses sonar waves to measure ETT migration and obstructions in real time. The aim of the present study is to assess the accuracy of the AirWave to evaluate ETT migration. In addition, we determined the degree of variation in ETT position and tested whether more pronounced migration occurs in specific clinical scenarios. After institutional review board approval, we included mechanically ventilated patients from February 2012 to May 2012. A chest radiography (CXR) was obtained at baseline and 24 hours when clinically indicated. The ETT distance at the lips was recorded at baseline and every 4 hours. The AirWave system continuously recorded ETT position changes from baseline, and luminal obstructions. A total of 42 patients (age: 61 [SD ±13] years, men: 52%) were recruited. A total of 19 patients had measurements of ETT migration at 24 hours by the 3 methodologies used in this study. The mean (SD) of the ETT migration at 24 hours was +0.04 (1.2), -0.42 (0.7) and +0.34 (1.81) cm when measured by portable CXR, ETT distance at the teeth and AirWave device, respectively. Bland-Altman analysis of tube migration at 24 hours comparing the AirWave with CXR readings showed a bias of 0.1 cm with 95% limit of agreement of -3.8 and +4.3 cm. Comparison of tube migration at 24 hours determined by AirWave with ETT distance at the lips revealed a bias of -0.4 with 95% limit of agreement -3.7 to +3 cm, similar to the values observed between CXR and ETT distance at the lips (bias of -0.3 cm, 95% limit of agreement of -3.4 to +2.8 cm). Factors associated with ETT migration at 24 hours were ETT size and initial measurement from ETT tip to carina by portable CXR. AirWave detected in eight patients some degree of ETT obstruction (30% ± 9.6%) that resolved with prompt ETT catheter suction. The AirWave may provide useful information regarding ETT

  12. Development of Wave Dragon from Scale 1:50 to Prototype

    DEFF Research Database (Denmark)

    Soerensen, H. C.; Friis-Madsen, E.; Panhauser, W.

    2003-01-01

    The Wave Dragon is a 4 to 11 MW offshore wave energy converter of the overtopping type. It basically consists of two wave reflectors focusing the waves towards a ramp, a reservoir for collecting the overtopping water and a number of hydro turbines for converting the pressure head into power....... In the period from 1998 to 2001 extensive testing on a scale 1:50 model was carried out. During the last month, testing has started on a prototype of the Wave Dragon in Nissum Bredning, Denmark (wave climate in scale 1:4.5 of the North Sea). The prototype has been grid connected in June 2003 as the world...

  13. AlScN thin film based surface acoustic wave devices with enhanced microfluidic performance

    International Nuclear Information System (INIS)

    Wang, W B; Xuan, W P; Chen, J K; Wang, X Z; Luo, J K; Fu, Y Q; Chen, J J; Duan, P F; Mayrhofer, P; Bittner, A; Schmid, U

    2016-01-01

    This paper reports the characterization of scandium aluminum nitride (Al 1−xS c xN , x   =  27%) films and discusses surface acoustic wave (SAW) devices based on them. Both AlScN and AlN films were deposited on silicon by sputtering and possessed columnar microstructures with (0 0 0 2) crystal orientation. The AlScN/Si SAW devices showed improved electromechanical coupling coefficients ( K 2 , ∼2%) compared with pure AlN films (<0.5%). The performance of the two types of devices was also investigated and compared, using acoustofluidics as an example. The AlScN/Si SAW devices achieved much lower threshold powers for the acoustic streaming and pumping of liquid droplets, and the acoustic streaming and pumping velocities were 2  ×  and 3  ×  those of the AlN/Si SAW devices, respectively. Mechanical characterization showed that the Young’s modulus and hardness of the AlN film decreased significantly when Sc was doped, and this was responsible for the decreased acoustic velocity and resonant frequency, and the increased temperature coefficient of frequency, of the AlScN SAW devices. (paper)

  14. Study of Dam-break Due to Overtopping of Four Small Dams in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Zakaraya Alhasan

    2015-01-01

    Full Text Available Dam-break due to overtopping is one of the most common types of embankment dam failures. During the floods in August 2002 in the Czech Republic, several small dams collapsed due to overtopping. In this paper, an analysis of the dam break process at the Luh, Velký Bělčický, Melín, and Metelský dams breached during the 2002 flood is presented. Comprehensive identification and analysis of the dam shape, properties of dam material and failure scenarios were carried out after the flood event to assemble data for the calibration of a numerical dam break model. A simple one-dimensional mathematical model was proposed for use in dam breach simulation, and a computer code was compiled. The model was calibrated using the field data mentioned above. Comparison of the erodibility parameters gained from the model showed reasonable agreement with the results of other authors.

  15. Recruitment of ichthyoplankton and macrozooplankton during overtopping events into a temporarily open/closed southern African estuary

    Science.gov (United States)

    Kemp, J. O. G.; Froneman, P. W.

    2004-11-01

    The composition and short-term temporal variation in the ichthyofauna and macrozooplankton entering the temporarily open/closed (TOC) West Kleinemond estuary (33°33'S, 27°02'E) during 7 overtopping events were investigated in June 2003. A total of 84 fish representing 7 taxa from 6 families and 456 macrozooplankton representing at least 16 species was collected from water overtopping the sandbar using a custom-built funnel trap (150 μm mesh). Larvae of estuarine dependant marine species, especially the sparid, Rhabdosargus holubi, which contributed 54% to the total fish catch, dominated the ichthyofauna. Also well represented among the ichthyofauna were Monodactylus falciformis and Mugilidae spp., which together accounted for a further 40% of the total fish catch. Among the macrozooplankton, larvae of Palaemon peringueyi and the mysid Mesopodopsis wooldridgei dominated numerically and by biomass. Numerical analyses using multidimensional scaling (MDS) revealed variability in the overtopping community on a diel scale. It is suggested that recruitment through overtopping is essentially a passive process governed by the physical environment with the composition of the recruiting community being a function of the patchy dynamics of surf zone plankton. Preliminary estimates indicate that an hour-long period of overtopping over spring high tide is capable of introducing between 8000 and 33 500 individuals of R. holubi into the TOC West Kleinemond estuary. The advantages and disadvantages of recruitment using overtopping events as well as impacts on the estuarine foodweb are discussed.

  16. Determination of the physical properties of room temperature ionic liquids using a Love wave device.

    Science.gov (United States)

    Ouali, F Fouzia; Doy, Nicola; McHale, Glen; Hardacre, Christopher; Ge, Rile; Allen, Ray W K; MacInnes, Jordan M; Newton, Michael I

    2011-09-01

    In this work, we have shown that a 100 MHz Love wave device can be used to determine whether room temperature ionic liquids (RTILs) are Newtonian fluids and have developed a technique that allows the determination of the density-viscosity product, ρη, of a Newtonian RTIL. In addition, a test for a Newtonian response was established by relating the phase change to insertion loss change. Five concentrations of a water-miscible RTIL and seven pure RTILs were measured. The changes in phase and insertion loss were found to vary linearly with the square root of the density-viscosity product for values up to (ρη)(1/2) ~ 10 kg m(-2) s(-1/2). The square root of the density-viscosity product was deduced from the changes in either phase or insertion loss using glycerol as a calibration liquid. In both cases, the deduced values of ρη agree well with those measured using viscosity and density meters. Miniaturization of the device, beyond that achievable with the lower-frequency quartz crystal microbalance approach, to measure smaller volumes is possible. The ability to fabricate Love wave and other surface acoustic wave sensors using planar metallization technologies gives potential for future integration into lab-on-a-chip analytical systems for characterizing ionic liquids.

  17. Wave Loadings on Seawave Slot-Cone Generator (SSG) at Kvitsøy Island

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Frigaard, Peter; Kofoed, Jens Peter

    This report presents results from a new research study performed to derive information on wave loadings acting on Wave Energy Convert (WEC) Seawave Slot-Cone Generator (SSG) exposed to extreme wave conditions. The SSG concept is based on the principle of overtopping and stores the wave energy...

  18. A new linear plasma device for the study of plasma waves in the electron magnetohydrodynamics regime

    Science.gov (United States)

    Joshi, Garima; Ravi, G.; Mukherjee, S.

    2018-06-01

    A new, user-friendly, linear plasma device has been developed in our laboratory where a quiescent (Δ n/n ≈ 1%), low temperature (1-10 eV), pulsed (3-10 ms) plasma can be produced over a large uniform region of 30-40 cm diameter and 40 cm length. Salient features of the device include the flexibility of tuning the plasma density in the range of 10^{10} to 10^{12} cm^{-3} and capability of scanning the plasma and field parameters in two dimensions with a precision of electromagnetic field parameters by miniature magnetic probes and Rogowski coils. The plasma produced is uniform and essentially unbounded for performing experiments on waves and turbulence. The whole device can be operated single-handedly by undergraduate or graduate students. The device can be opened, serviced, new antennas/probes installed and ready for operation in a matter of hours. Some results on the excitation of electromagnetic structures in the context of electron magnetohydrodynamics (EMHD) are also presented to demonstrate the suitability of the device for carrying out such experiments.

  19. A Microfluidic Love-Wave Biosensing Device for PSA Detection Based on an Aptamer Beacon Probe.

    Science.gov (United States)

    Zhang, Feng; Li, Shuangming; Cao, Kang; Wang, Pengjuan; Su, Yan; Zhu, Xinhua; Wan, Ying

    2015-06-11

    A label-free and selective aptamer beacon-based Love-wave biosensing device was developed for prostate specific antigen (PSA) detection. The device consists of the following parts: LiTaO3 substrate with SiO2 film as wave guide layer, two set of inter-digital transducers (IDT), gold film for immobilization of the biorecongniton layer and a polydimethylsiloxane (PDMS) microfluidic channels. DNA aptamer, or "artificial antibody", was used as the specific biorecognition probe for PSA capture. Some nucleotides were added to the 3'-end of the aptamer to form a duplex with the 3'-end, turning the aptamer into an aptamer-beacon. Taking advantage of the selective target-induced assembly changes arising from the "aptamer beacon", highly selective and specific detection of PSA was achieved. Furthermore, PDMS microfluidic channels were designed and fabricated to realize automated quantitative sample injection. After optimization of the experimental conditions, the established device showed good performance for PSA detection between 10 ng/mL to 1 μg/mL, with a detection limit of 10 ng/mL. The proposed sensor might be a promising alternative for point of care diagnostics.

  20. Wave Intensity Analysis of Right Ventricular Function during Pulsed Operation of Rotary Left Ventricular Assist Devices.

    Science.gov (United States)

    Bouwmeester, J Christopher; Park, Jiheum; Valdovinos, John; Bonde, Pramod

    2018-05-29

    Changing the speed of left ventricular assist devices (LVADs) cyclically may be useful to restore aortic pulsatility; however, the effects of this pulsation on right ventricular (RV) function are unknown. This study investigates the effects of direct ventricular interaction by quantifying the amount of wave energy created by RV contraction when axial and centrifugal LVADs are used to assist the left ventricle. In 4 anesthetized pigs, pressure and flow were measured in the main pulmonary artery and wave intensity analysis was used to identify and quantify the energy of waves created by the RV. The axial pump depressed the intensity of waves created by RV contraction compared with the centrifugal pump. In both pump designs, there were only minor and variable differences between the continuous and pulsed operation on RV function. The axial pump causes the RV to contract with less energy compared with a centrifugal design. Diminishing the ability of the RV to produce less energy translates to less pressure and flow produced, which may lead to LVAD-induced RV failure. The effects of pulsed LVAD operation on the RV appear to be minimal during acute observation of healthy hearts. Further study is necessary to uncover the effects of other modes of speed modulation with healthy and unhealthy hearts to determine if pulsed operation will benefit patients by reducing LVAD complications.

  1. Analysis and Synthesis of Leaky-Wave Devices in Planar Technology

    Science.gov (United States)

    Martinez Ros, Alejandro Javier

    The work developed along this doctoral thesis has been focused on the analysis and synthesis of microwave devices in planar technology. In particular, several types of devices based on the radiation mechanism of leaky waves have been studied. Typically, the radiation properties in leaky-wave devices are determined by the complex propagation constant of the leaky mode, wherein the phase constant is responsible for the pointing angle and the leakage rate for the intensity of the radiated fields. In this manner, by controlling both amplitude and phase of the leaky mode, an effective control over the device's radiation diagram can be obtained. Moreover, with the purpose of efficiently obtaining the leaky mode's radiation properties as function of the main geometrical parameters of the structure, several modal tools based on the transverse resonance analysis of the structure have been performed. In order to demonstrate this simultaneous control over the complex propagation constant in planar technology, several types of leaky-wave devices, including antennas (LWAs), multiplexors and near-field focusing systems, have been designed and manufactured in the technology of substrate integrated waveguide (SIW). This recently proposed technology, allows the design of devices based on classical waveguide technology with standard manufacturing techniques used for printed circuit board (PCB) designs. In this way, most of the parts that form a communication system can be integrated into a single substrate, thus reducing its cost and providing a more robust and compact device, which has less losses compared to other planar technologies such as the microstrip. El trabajo llevado a cabo durante la realizacion de esta tesis doctoral, se ha centrado en el analisis y sintesis de dispositivos de microondas en tecnologia planar. En concreto, se han estudiado diferentes tipos de dispositivos basados en radiacion por ondas de fuga "leaky waves", en los cuales las propiedades de radiacion

  2. Nanoporous metal film: An energy-dependent transmission device for electron waves

    International Nuclear Information System (INIS)

    Grech, S.; Degiovanni, A.; Lapena, L.; Morin, R.

    2011-01-01

    We measure electron transmission through free-standing ultrathin nanoporous gold films, using the coherent electron beam emitted by sharp field emission tips in a low energy electron projection microscope setup. Transmission coefficient versus electron wavelength plots show periodic oscillations between 75 and 850 eV. These oscillations result from the energy dependence of interference between paths through the gold and paths through the nanometer-sized pores of the film. We reveal that these films constitute high transmittance quantum devices acting on electron waves through a wavelength-dependent complex transmittance defined by the porosity and the thickness of the film.

  3. Surface acoustic wave devices on AlN/3C–SiC/Si multilayer structures

    International Nuclear Information System (INIS)

    Lin, Chih-Ming; Lien, Wei-Cheng; Riekkinen, Tommi; Senesky, Debbie G; Pisano, Albert P; Chen, Yung-Yu; Felmetsger, Valery V

    2013-01-01

    Surface acoustic wave (SAW) propagation characteristics in a multilayer structure including a piezoelectric aluminum nitride (AlN) thin film and an epitaxial cubic silicon carbide (3C–SiC) layer on a silicon (Si) substrate are investigated by theoretical calculation in this work. Alternating current (ac) reactive magnetron sputtering was used to deposit highly c-axis-oriented AlN thin films, showing the full width at half maximum (FWHM) of the rocking curve of 1.36° on epitaxial 3C–SiC layers on Si substrates. In addition, conventional two-port SAW devices were fabricated on the AlN/3C–SiC/Si multilayer structure and SAW propagation properties in the multilayer structure were experimentally investigated. The surface wave in the AlN/3C–SiC/Si multilayer structure exhibits a phase velocity of 5528 m s −1 and an electromechanical coupling coefficient of 0.42%. The results demonstrate the potential of AlN thin films grown on epitaxial 3C–SiC layers to create layered SAW devices with higher phase velocities and larger electromechanical coupling coefficients than SAW devices on an AlN/Si multilayer structure. Moreover, the FWHM values of rocking curves of the AlN thin film and 3C–SiC layer remained constant after annealing for 500 h at 540 °C in air atmosphere. Accordingly, the layered SAW devices based on AlN thin films and 3C–SiC layers are applicable to timing and sensing applications in harsh environments. (paper)

  4. Wave energy extraction by coupled resonant absorbers.

    Science.gov (United States)

    Evans, D V; Porter, R

    2012-01-28

    In this article, a range of problems and theories will be introduced that will build towards a new wave energy converter (WEC) concept, with the acronym 'ROTA' standing for resonant over-topping absorber. First, classical results for wave power absorption for WECs constrained to operate in a single degree of freedom will be reviewed and the role of resonance in their operation highlighted. Emphasis will then be placed on how the introduction of further resonances can improve power take-off characteristics by extending the range of frequencies over which the efficiency is close to a theoretical maximum. Methods for doing this in different types of WECs will be demonstrated. Coupled resonant absorbers achieve this by connecting a WEC device equipped with its own resonance (determined from a hydrodynamic analysis) to a new system having separate mass/spring/damper characteristics. It is shown that a coupled resonant effect can be realized by inserting a water tank into a WEC, and this idea forms the basis of the ROTA device. In essence, the idea is to exploit the coupling between the natural sloshing frequencies of the water in the internal tank and the natural resonance of a submerged buoyant circular cylinder device that is tethered to the sea floor, allowing a rotary motion about its axis of attachment.

  5. Broadband modulation of terahertz waves through electrically driven hybrid bowtie antenna-VO2 devices.

    Science.gov (United States)

    Han, Chunrui; Parrott, Edward P J; Humbert, Georges; Crunteanu, Aurelian; Pickwell-MacPherson, Emma

    2017-10-05

    Broadband modulation of terahertz (THz) light is experimentally realized through the electrically driven metal-insulator phase transition of vanadium dioxide (VO 2 ) in hybrid metal antenna-VO 2 devices. The devices consist of VO 2 active layers and bowtie antenna arrays, such that the electrically driven phase transition can be realized by applying an external voltage between adjacent metal wires extended to a large area array. The modulation depth of the terahertz light can be initially enhanced by the metal wires on top of VO 2 and then improved through the addition of specific bowties in between the wires. As a result, a terahertz wave with a large beam size (~10 mm) can be modulated within the measurable spectral range (0.3-2.5 THz) with a frequency independent modulation depth as high as 0.9, and the minimum amplitude transmission down to 0.06. Moreover, the electrical switch on/off phase transition depends very much on the size of the VO 2 area, indicating that smaller VO 2 regions lead to higher modulation speeds and lower phase transition voltages. With the capabilities in actively tuning the beam size, modulation depth, modulation bandwidth as well as the modulation speed of THz waves, our study paves the way in implementing multifunctional components for terahertz applications.

  6. Laser-generated shock wave attenuation aimed at microscale pyrotechnic device design

    Directory of Open Access Journals (Sweden)

    Hyeonju Yu

    2016-05-01

    Full Text Available To meet the rising demand for miniaturizing the pyrotechnic device that consists of donor/acceptor pair separated by a bulkhead or a thin gap, the shock initiation sensitivity in the microscale gap test configuration is investigated. For understanding the shock attenuation within a gap sample (304 stainless steel thickness of 10∼800 μm, the laser-generated shock wave in water confinement is adopted. The shock properties are obtained from the free surface velocity by making use of a velocity interferometer system for any reflector (VISAR. Analytical models for plasma generation in a confined geometry and for evolution and decay of shock waves during the propagation are considered. The shape and amplitude of the laser-driven initial pressure load and its attenuation pattern in the gap are effectively controlled for targeting the microscale propagation distance and subsequent triggering pressure for the acceptor charge. The reported results are important in the precise controlling of the shock strength during the laser initiation of microscale pyrotechnic devices.

  7. System and Method for Measuring the Transfer Function of a Guided Wave Device

    Science.gov (United States)

    Froggatt, Mark E. (Inventor); Erdogan, Turan (Inventor)

    2002-01-01

    A method/system are provided for measuring the NxN scalar transfer function elements for an N-port guided wave device. Optical energy of a selected wavelength is generated at a source and directed along N reference optical paths having N reference path lengths. Each reference optical path terminates in one of N detectors such that N reference signals are produced at the N detectors. The reference signals are indicative of amplitude, phase and frequency of the optical energy carried along the N reference optical paths. The optical energy from the source is also directed to the N-ports of the guided wave device and then on to each of the N detectors such that N measurement optical paths are defined between the source and each of the N detectors. A portion of the optical energy is modified in terms of at least one of the amplitude and phase to produce N modified signals at each of the N detectors. At each of the N detectors, each of the N modified signals is combined with a corresponding one of the N reference signals to produce corresponding N combined signals at each of the N detectors. A total of N(sup 2) measurement signals are generated by the N detectors. Each of the N(sup 2) measurement signals is sampled at a wave number increment (Delta)k so that N(sup 2) sampled signals are produced. The NxN transfer function elements are generated using the N(sup 2) sampled signals. Reference and measurement path length constraints are defined such that the N combined signals at each of the N detectors are spatially separated from one another in the time domain.

  8. SSG Wave Energy Converter

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Vicinanza, Diego; Frigaard, Peter

    2008-01-01

    The SSG (Sea Slot-cone Generator) is a wave energy converter of the overtopping type. The structure consists of a number of reservoirs one on the top of each others above the mean water level, in which the water of incoming waves is stored temporary. In each reservoir, expressively designed low...... head hydroturbines are converting the potential energy of the stored water into power. A key to success for the SSG will be the low cost of the structure and its robustness. The construction of the pilot plant is scheduled and this paper aims to describe the concept of the SSG wave energy converter...

  9. Innovative Breakwaters Design for Wave Energy Conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Stagonas, D.; Müller, G.

    2012-01-01

    the rubble mound breakwaters and seawalls related activity and the energy demand of small human communities. Wave loadings and overtopping on a seawall and rubble mound breakwater with front reservoir are discussed on the basis of physical 2-D model tests carried out at University of Southampton (UK...

  10. Characterization of Zinc Oxide (ZnO) piezoelectric properties for Surface Acoustic Wave (SAW) device

    Science.gov (United States)

    Rosydi Zakaria, Mohd; Johari, Shazlina; Hafiz Ismail, Mohd; Hashim, Uda

    2017-11-01

    In fabricating Surface Acoustic Wave (SAW) biosensors device, the substrate is one of important factors that affected to performance device. there are many types of piezoelectric substrate in the markets and the cheapest is zinc Oxide substrate. Zinc Oxide (ZnO) with its unique properties can be used as piezoelectric substrate along with SAW devices for detection of DNA in this research. In this project, ZnO thin film is deposited onto silicon oxide substrate using electron beam evaporation (E-beam) and Sol-Gel technique. Different material structure is used to compare the roughness and best piezoelectric substrate of ZnO thin film. Two different structures of ZnO target which are pellet and granular are used for e-beam deposition and one sol-gel liquid were synthesize and compared. Parameter for thickness of ZnO e-beam deposition is fixed to a 0.1kÅ for both materials structure and sol-gel was coat using spin coat technique. After the process is done, samples are annealed at temperature of 500°C for 2 hours. The structural properties of effect of post annealing using different material structure of ZnO are studied using Atomic Force Microscopic (AFM) for surface morphology and X-ray Diffraction (XRD) for phase structure.

  11. Wave Forces and Overtopping on Crown Walls of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Pedersen, Jan

    The scientific progress of our understanding of the interaction between coastal structures and the sea has greatly improved in the recent years. The present state of knowledge includes structural and financial optimization of the structures based on reliability evaluations. The first requirement....... The stability of crown wall structures has also been investigated and a new methodology for the evaluation of the geodynamic response of the foundation is presented....

  12. Numerical Modeling of Wave Overtopping of Buffalo Harbor Confined Disposal Facility (CDF4)

    Science.gov (United States)

    2017-10-01

    navigation channel , and harbor complex. Though there are anecdotal claims and debris indicating possible sediment movement, there has been no evidence of...littoral sediments inside the disposal area, into the channel and harbor, and other adjacent areas to the CDF4. 1.4 Study plan 1.4.1 Purpose There...locations. 2.4 Maintenance dredging data The need for maintenance dredging arises from sedimentation in the navigation channels , which impedes

  13. Study of a Novel Oscillating Surge Wave Energy Converter: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Tom, Nathan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Choiniere, Michael [University of Maine; Thiagarajan, Krish P. [University of Maine

    2017-08-01

    This study investigates the performance of an oscillating surge wave energy converter (OSWEC) that utilizes adjustable geometry as a means of controlling the hydrodynamic coefficients, a concept originally proposed by [1]. The body of the device consists of a bottom-hinged solid rectangular frame with five horizontal flaps spanning the interior of the frame. The flaps can rotate independently about their center of rotation within the frame like a large window shutter. Changing the orientation of the flaps alters the hydrodynamic coefficients and natural frequency of the device as well as the ability to shed or absorb structural loads accordingly. This ability may allow the device to operate in a wider range of sea states than other current wave energy converter designs. This paper presents and compares the results of numerical simulations and experimental testing of the OSWEC's response to regular waves with all five of the horizontal fin configurations sharing the same orientation of 0 degrees (fully closed interior) and 90 degrees (fully open). The numerical simulations were performed using WAMIT, which calculates hydrodynamic coefficients using a boundary element method code to solve the linear potential flow problem, and WEC-Sim, a MATLAB-based tool that simulates multibody devices in the time domain by solving the governing equations of motion. A 1:14 scale model of the device was built for experimental evaluation in an 8-m-long, 1-m wide wave tank, which supports a water depth of 0.7 m. The OSWEC motion in different wave conditions was measured with displacement sensors while nonlinear wave-structure interaction effects like slamming and overtopping were captured using a high-speed camera and used to understand differences between the simulation and experiments.

  14. Comparison of electrostatic and electromagnetic synchronization of drift waves and suppression of drift wave turbulence in a linear device

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, C; Grulke, O; Klinger, T, E-mail: christian.brandt@lpmi.uhp-nancy.f [Max-Planck-Institute for Plasma Physics, EURATOM Association, Wendelsteinstrasse 1, D-17491 Greifswald (Germany)

    2010-05-15

    Experiments in a cylindrical magnetized plasma on the control of drift waves by means of two different spatiotemporal open-loop control systems-an electrostatic and an electromagnetic exciter-are reported. The drift wave dynamics is controlled by a mode-selective signal created with azimuthal arrangements of eight electrodes and eight saddle coils, respectively. Nonlinear interaction between the control signals and drift waves is observed, leading to synchronization of coherent drift waves and suppression of broadband drift wave turbulence. The cross-phase between density and potential fluctuations reduces from {approx}{pi}/2 in turbulence to {approx}0 in controlled turbulence. Hence, the cross-field transport is reduced to the level of coherent drift waves. For both control systems the coupling to the drift wave can be ascribed to the drive of parallel currents, on the one hand via direct electric contact and, on the other hand, via electromagnetic induction.

  15. Overtopping hazards to port activities: Application of a new methodology to risk management (POrt Risk MAnagement Tool)

    International Nuclear Information System (INIS)

    Alises, Ana; Molina, Rafael; Gómez, Rebeca; Pery, Pascual; Castillo, Carmen

    2014-01-01

    In the past 20 years, the need of ports to serve a fleet whose dimensions are continuously increasing due to economies of scale, has derived on a port infrastructures growth with a trend to look for greater drafts at deeper waters and therefore the protection structures built in the last years have been increasingly exposed to severer maritime climate action. Consequently, overtopping phenomenon has been identified as a potential risk factor able to cause structural damages and operative failure modes to vulnerable economic activities located at these port facilities. Port activities must be developed ensuring operative and safety conditions what imply reducing uncertainties of overtopping phenomena by using prediction methods which may allow overtopping risk management. This paper provides a risk assessment methodology which is integrated into an overtopping risk management framework to cope with safety problems in port exploitation. Overtopping risk value is measured by combining probability of occurrence of an undesirable event together with its consequences, estimated in terms of costs or delays and given in base of the vulnerability of the affected port system. The development of this methodology is described and finally applied to a real case study what seems to reinforce the validity of the proposed method to overtopping risk assessment. - Highlights: • Infrastructure risk assessment involves both probabilistic and economic techniques. • Risk equation is posed by the combination of probability, vulnerability and cost. • Port infrastructures' vulnerability level depends on climate agents' action. • Economic value of natural hazards consequences is linked with vulnerability level. • Project planning process should be done taking into account the project's risk distribution

  16. A portable pulmonary delivery system for nano engineered DNA vaccines driven by surface acoustic wave devices

    International Nuclear Information System (INIS)

    Rajapaksa, A.E.; Qi, Aisha; Yeo, L.; Friend, J.

    2010-01-01

    Full text: The increase in the need for effective delivery of potelll vaccines against infectious diseases, require robust yet straightforward pro duction of encapsulated DNA-laden aerosols. Aerosol delivery of drugs represents the next generation of vaccine delivery where the drug is deposited into the lung, which provides an ideal, non-invasive route. Moreover, several features of D A vaccines make them more attractive than conventional vaccines; thus, DNA vaccines have gained global interest for a variety of applications. However, several limitations such as ineffective cellular uptake and intracellular delivery, and degradation of DNA need to be overcome before clin ical applications. In this study, a novel and scalable engineered technique has been developed to create a biodegradable polymer system, which enables controlled delivery of a well designed DNA vaccine for immuno-therapeutics. Surface Acoustic Wave (SAW) atomisation has been found as useful mechanism for atomising fluid samples for medical and industrial devices. It is a straightforward method for synthesising un-agglomerated biodegradable nanoparti cles (<250 nm) in the absence of organic solvents which would represent a major breakthrough for biopharmaceutical encapsulation and delivery. Nano-scale polymer particles for DNA vaccines deliv ery were obtained through an evaporative process of the initial aerosol created by surface acoustic waves at 8-150 MHz, the final size of which could be controlled by modifying the initial polymer concen tration and solid contents. Thus, SAW atomiser represents a promising alternative for the development of a low power device for producing nano-engineered vaccines with a controlled and narrow size distribution as delivery system for genetic immuno-therapeutics.

  17. Comparison of Homogenous and Multi-layered Berm Breakwaters with Respect to Overtopping and Front Slope Stability

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Skals, K. T.; Burcharth, Hans F.

    2009-01-01

    A model test study was conducted to study overtopping and front slope stability of homogenous and multi-layered berm breakwaters. The two breakwater types are compared and cons and pros are listed. The study shows that the optimum number of stone classes might be significantly lower than what has...... previously been used in the Icelandic type of berm breakwater because it seems that the number of stone classes in the berm can be reduced from five to two without significantly influencing overtopping and stability performance. Moreover, the new results are compared to the design formulae established...

  18. The Characterization of Surface Acoustic Wave Devices Based on AlN-Metal Structures

    Directory of Open Access Journals (Sweden)

    Lin Shu

    2016-04-01

    Full Text Available We report in this paper on the study of surface acoustic wave (SAW resonators based on an AlN/titanium alloy (TC4 structure. The AlN/TC4 structure with different thicknesses of AlN films was simulated, and the acoustic propagating modes were discussed. Based on the simulation results, interdigital transducers with a periodic length of 24 μm were patterned by lift-off photolithography techniques on the AlN films/TC4 structure, while the AlN film thickness was in the range 1.5–3.5 μm. The device performances in terms of quality factor (Q-factor and electromechanical coupling coefficient (k2 were determined from the measure S11 parameters. The Q-factor and k2 were strongly dependent not only on the normalized AlN film thickness but also on the full-width at half-maximum (FWHM of AlN (002 peak. The dispersion curve of the SAW phase velocity was analyzed, and the experimental results showed a good agreement with simulations. The temperature behaviors of the devices were also presented and discussed. The prepared SAW resonators based on AlN/TC4 structure have potential applications in integrated micromechanical sensing systems.

  19. Uncertainty Analysis and Overtopping Risk Evaluation of Maroon Dam withMonte Carlo and Latin Hypercube Methods

    Directory of Open Access Journals (Sweden)

    J. M. Vali Samani

    2016-02-01

    Full Text Available Introduction: The greatest part of constructed dams belongs to embankment dams and there are many examples of their failures throughout history. About one-third of the world’s dam failures have been caused by flood overtopping, which indicates that flood overtopping is an important factor affecting reservoir projects’ safety. Moreover, because of a poor understanding of the randomness of floods, reservoir water levels during flood seasons are often lowered artificially in order to avoid overtopping and protect the lives and property of downstream residents. So, estimation of dam overtopping risk with regard to uncertainties is more important than achieving the dam’s safety. This study presents the procedure for risk evaluation of dam overtopping due to various uncertaintiess in inflows and reservoir initial condition. Materials and Methods: This study aims to present a practical approach and compare the different uncertainty analysis methods in the evaluation of dam overtopping risk due to flood. For this purpose, Monte Carlo simulation and Latin hypercube sampling methods were used to calculate the overtopping risk, evaluate the uncertainty, and calculate the highest water level during different flood events. To assess these methods from a practical point of view, the Maroon dam was chosen for the case study. Figure. 1 indicates the work procedure, including three parts: 1 Identification and evaluation of effective factors on flood routing and dam overtopping, 2 Data collection and analysis for reservoir routing and uncertainty analysis, 3 Uncertainty and risk analysis. Figure 1- Diagram of dam overtopping risk evaluation Results and Discussion: Figure 2 shows the results of the computed overtopping risks for the Maroon Dam without considering the wind effect, for the initial water level of 504 m as an example. As it is shown in Figure. 2, the trends of the risk curves computed by the different uncertainty analysis methods are similar

  20. Heat Transfer Characteristics of a Focused Surface Acoustic Wave (F-SAW Device for Interfacial Droplet Jetting

    Directory of Open Access Journals (Sweden)

    Donghwi Lee

    2018-06-01

    Full Text Available In this study, we investigate the interfacial droplet jetting characteristics and thermal stability of a focused surface acoustic wave device (F-SAW. An F-SAW device capable of generating a 20 MHz surface acoustic wave by applying sufficient radio frequency power (2–19 W on a 128°-rotated YX-cut piezoelectric lithium niobate substrate for interfacial droplet jetting is proposed. The interfacial droplet jetting characteristics were visualized by a shadowgraph method using a high-speed camera, and a heat transfer experiment was conducted using K-type thermocouples. The interfacial droplet jetting characteristics (jet angle and height were analyzed for two different cases by applying a single interdigital transducer and two opposite interdigital transducers. Surface temperature variations were analyzed with radio frequency input power increases to evaluate the thermal stability of the F-SAW device in air and water environments. We demonstrate that the maximum temperature increase of the F-SAW device in the water was 1/20 of that in the air, owing to the very high convective heat transfer coefficient of the water, resulting in prevention of the performance degradation of the focused acoustic wave device.

  1. Quantifying the uncertainty of wave energy conversion device cost for policy appraisal: An Irish case study

    International Nuclear Information System (INIS)

    Farrell, Niall; Donoghue, Cathal O’; Morrissey, Karyn

    2015-01-01

    Wave Energy Conversion (WEC) devices are at a pre-commercial stage of development with feasibility studies sensitive to uncertainties surrounding assumed input costs. This may affect decision making. This paper analyses the impact these uncertainties may have on investor, developer and policymaker decisions using an Irish case study. Calibrated to data present in the literature, a probabilistic methodology is shown to be an effective means to carry this out. Value at Risk (VaR) and Conditional Value at Risk (CVaR) metrics are used to quantify the certainty of achieving a given cost or return on investment. We analyse the certainty of financial return provided by the proposed Irish Feed-in Tariff (FiT) policy. The influence of cost reduction through bulk discount is also discussed, with cost reduction targets for developers identified. Uncertainty is found to have a greater impact on the profitability of smaller installations and those subject to lower rates of cost reduction. This paper emphasises that a premium is required to account for cost uncertainty when setting FiT rates. By quantifying uncertainty, a means to specify an efficient premium is presented. - Highlights: • Probabilistic model quantifies uncertainty for wave energy feasibility analyses. • Methodology presented and applied to an Irish case study. • A feed-in tariff premium of 3–4 c/kWh required to account for cost uncertainty. • Sensitivity of uncertainty and cost to rates of technological change analysed. • Use of probabilistic model for investors and developers also demonstrated

  2. Framing 100-year overflowing and overtopping marine submersion hazard resulting from the propagation of 100-year joint hydrodynamic conditions

    Science.gov (United States)

    Nicolae Lerma, A.; Bulteau, T.; Elineau, S.; Paris, F.; Pedreros, R.

    2016-12-01

    Marine submersion is an increasing concern for coastal cities as urban development reinforces their vulnerabilities while climate change is likely to foster the frequency and magnitude of submersions. Characterising the coastal flooding hazard is therefore of paramount importance to ensure the security of people living in such places and for coastal planning. A hazard is commonly defined as an adverse phenomenon, often represented by a magnitude of a variable of interest (e.g. flooded area), hereafter called response variable, associated with a probability of exceedance or, alternatively, a return period. Characterising the coastal flooding hazard consists in finding the correspondence between the magnitude and the return period. The difficulty lies in the fact that the assessment is usually performed using physical numerical models taking as inputs scenarios composed by multiple forcing conditions that are most of the time interdependent. Indeed, a time series of the response variable is usually not available so we have to deal instead with time series of forcing variables (e.g. water level, waves). Thus, the problem is twofold: on the one hand, the definition of scenarios is a multivariate matter; on the other hand, it is tricky and approximate to associate the resulting response, being the output of the physical numerical model, to the return period defined for the scenarios. In this study, we illustrate the problem on the district of Leucate, located in the French Mediterranean coast. A multivariate extreme value analysis of waves and water levels is performed offshore using a conditional extreme model, then two different methods are used to define and select 100-year scenarios of forcing variables: one based on joint exceedance probability contours, a method classically used in coastal risks studies, the other based on environmental contours, which are commonly used in the field of structure design engineering. We show that these two methods enable one to

  3. Hydraulic Response of Caisson Breakwaters in Multidirectional Breaking and Non-Breaking Waves

    DEFF Research Database (Denmark)

    Grønbech, J.; Kofoed, Jens Peter; Hald, Tue

    1998-01-01

    The present paper concerns the results and findings of a physical study on wave impacts on vertical caisson breakwaters situated in irregular, multidirectional breaking seas. The study has taken place as part of the framework programme "Dynamic of Structures" financially supported by the Danish T...... breaking waves at deep water. The study on wave overtopping showed that the 3D wave overtopping formula suggested by Franco et al., 1995b, predicts the wave overtopping reasonable well for both non breaking and breaking waves at deep water.......The present paper concerns the results and findings of a physical study on wave impacts on vertical caisson breakwaters situated in irregular, multidirectional breaking seas. The study has taken place as part of the framework programme "Dynamic of Structures" financially supported by the Danish...... induced loading and overtopping on caisson breakwaters situated in breaking seas. Regarding the wave forces only minor differences between breaking and non breaking waves in deep water were observed, and it was found that the prediction formula of Goda also seems to apply well for multidirectionally...

  4. Experimental Hydraulic Optimization of the Wave Energy Converter Seawave Slot-Cone Generator

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter

    This report presents the results of a experimental hydraulic optimization of the wave energy convert (WEC) Seawave Slot-Cone Generator (SSG). SSG is a WEC utilizing wave overtopping in multiple reservoirs. In the present SSG setup three reservoirs has been used. Model tests have been performed...

  5. A study of Love wave devices in ZnO/Quartz and ZnO/LiTaO3 structures

    International Nuclear Information System (INIS)

    Chang, R.-C.; Chu, S.-Y.; Hong, C.-S.; Chuang, Y.-T.

    2006-01-01

    Love wave devices are very promising for sensing applications because of high sensitivity. In this paper, ZnO thin films doped with lithium (Li) and magnesium (Mg) were deposited on the 42 o 45' ST-cut quartz and 36 o YX-LiTaO 3 substrates by RF magnetron sputtering technique. XRD, SEM, and AFM measurements investigated characteristics of the films. Under different conditions such as doping content, layer thickness, and substrate temperature, the phase velocity, temperature coefficient of frequency, electromechanical coupling coefficient and sensitivity of Love wave devices in ZnO/Quartz and ZnO/LiTaO 3 structures are presented. The maximum sensitivities of ZnO/Quartz and ZnO/LiTaO 3 are much higher than the SiO 2 /Quartz and SiO 2 /LiTaO 3 structures reported

  6. Validation study of a drift-wave turbulence model for CSDX linear plasma device

    Science.gov (United States)

    Vaezi, P.; Holland, C.; Thakur, S. C.; Tynan, G. R.

    2017-09-01

    A validation study of self-regulating drift-wave turbulence/zonal flow dynamics in the Controlled Shear Decorrelation Experiment linear plasma device using Langmuir probe synthetic diagnostics is presented in this paper. We use a set of nonlocal 3D equations, which evolve density, vorticity, and electron temperature fluctuations, and include proper sheath boundary conditions. Nonlinear simulations of these equations are carried out using BOUndary Turbulence (BOUT++) framework. To identify the dominant parametric dependencies of the model, a linear growth rate sensitivity analysis is performed using input parameter uncertainties, which are taken from the experimental measurements. For the direct comparison of nonlinear simulation results to experiment, we use synthetic Langmuir probe diagnostics to generate a set of synthetic ion saturation current and floating potential fluctuations. In addition, comparisons of azimuthal velocities determined via time-delay estimation, and nonlinear energy transfer are shown. We observe a significant improvement of model-experiment agreement relative to the previous 2D simulations. An essential component of this improved agreement is found to be the effect of electron temperature fluctuations on floating potential measurements, which introduces clear amplitude and phase shifts relative to the plasma potential fluctuations in synthetically measured quantities, where the simulations capture the experimental measurements in the core of plasma. However, the simulations overpredict the fluctuation levels at larger radii. Moreover, systematic simulation scans show that the self-generated E × B zonal flows profile is very sensitive to the steepening of density equilibrium profile. This suggests that evolving both fluctuations and equilibrium profiles, along with the inclusion of modest axial variation of radial profiles in the model are needed for further improvement of simulation results against the experimental measurements.

  7. Design of a non-linear power take-off simulator for model testing of rotating wave energy devices

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, M.F.P.; Henriques, J.C.C.; Lopes, Miguel C.; Gato, L.M.C. [IDMEC - Instituto de Engenharia Mecanica, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Lisboa (Portugal); Dente Antonio [CIE3 - Center for Innovation in Electrical and Energy Engineering, Lisboa (Portugal)

    2009-07-01

    Eddy current brakes provide a versatile way of simulating the power take-off system (PTO) in the model testing of wave energy converters at small scale. These are based on the principle that a conductive material moving perpendicularly to a magnetic field generates a braking force proportional to its velocity. This was applied in the design of the PTO simulator of a bottom-hinged flap wave energy converter model, at 1/16 scale. The efforts put into the accurate dynamic simulation of the device led to the development of a controllable PTO simulator, which can be applied to other small scale rotating wave energy device models. A special power source was built to provide the required controllable current intensity to feed the magnetic field generating coils. Different non-linear damping PTO characteristic curves can be simulated by basing the current control on real-time velocity measurement. The calibration of the system was done by connecting the device to a constant rotating speed motor and measuring the resistent torque produced by the PTO with a torquemeter for different values of current intensity through the coils.

  8. Passive Wireless Hydrogen Sensors Using Orthogonal Frequency Coded Acoustic Wave Devices, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes the development of passive surface acoustic wave (SAW) based hydrogen sensors for NASA application to distributed wireless hydrogen leak...

  9. Recent advances in particle and droplet manipulation for lab-on-a-chip devices based on surface acoustic waves.

    Science.gov (United States)

    Wang, Zhuochen; Zhe, Jiang

    2011-04-07

    Manipulation of microscale particles and fluid liquid droplets is an important task for lab-on-a-chip devices for numerous biological researches and applications, such as cell detection and tissue engineering. Particle manipulation techniques based on surface acoustic waves (SAWs) appear effective for lab-on-a-chip devices because they are non-invasive, compatible with soft lithography micromachining, have high energy density, and work for nearly any type of microscale particles. Here we review the most recent research and development of the past two years in SAW based particle and liquid droplet manipulation for lab-on-a-chip devices including particle focusing and separation, particle alignment and patterning, particle directing, and liquid droplet delivery.

  10. Current generation by unidirectional lower hybrid waves in the ACT-1 toroidal device

    International Nuclear Information System (INIS)

    Wong, K.L.; Horton, R.; Ono, M.

    1980-05-01

    An unambiguious experimental observation of current generation by unidirectional lower hybrid waves in a toroidal plasma is reported. Up to 10 amperes of current was driven by 500 watts of rf power at 160 MHz

  11. PASSIVE WIRELESS MULTI-SENSOR TEMPERATURE AND PRESSURE SENSING SYSTEM USING ACOUSTIC WAVE DEVICES, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes the development of passive surface acoustic wave (SAW) sensors and multi-sensor systems for NASA application to remote wireless sensing of...

  12. Development and experimental verification of a finite element method for accurate analysis of a surface acoustic wave device

    Science.gov (United States)

    Mohibul Kabir, K. M.; Matthews, Glenn I.; Sabri, Ylias M.; Russo, Salvy P.; Ippolito, Samuel J.; Bhargava, Suresh K.

    2016-03-01

    Accurate analysis of surface acoustic wave (SAW) devices is highly important due to their use in ever-growing applications in electronics, telecommunication and chemical sensing. In this study, a novel approach for analyzing the SAW devices was developed based on a series of two-dimensional finite element method (FEM) simulations, which has been experimentally verified. It was found that the frequency response of the two SAW device structures, each having slightly different bandwidth and center lobe characteristics, can be successfully obtained utilizing the current density of the electrodes via FEM simulations. The two SAW structures were based on XY Lithium Niobate (LiNbO3) substrates and had two and four electrode finger pairs in both of their interdigital transducers, respectively. Later, SAW devices were fabricated in accordance with the simulated models and their measured frequency responses were found to correlate well with the obtained simulations results. The results indicated that better match between calculated and measured frequency response can be obtained when one of the input electrode finger pairs was set at zero volts and all the current density components were taken into account when calculating the frequency response of the simulated SAW device structures.

  13. Design and simulation study of high frequency response for surface acoustic wave device by using CST software

    Science.gov (United States)

    Zakaria, M. R.; Hashim, U.; Amin, Mohd Hasrul I. M.; Ayub, R. Mat; Hashim, M. N.; Adam, T.

    2015-05-01

    This paper focuses on the enhancement and improvement of the Surface Acoustic Wave (SAW) device performance. Due to increased demand in the international market for biosensor product, the product must be emphasized in terms of quality. However, within the technological advances, demand for device with low cost, high efficiency and friendly-user preferred. Surface Acoustic Wave (SAW) device with the combination of pair electrode know as Interdigital Transducer (IDT) was fabricated on a piezoelectric substrate. The design of Interdigital Transducer (IDT) parameter is changes in several sizes and values for which it is able to provide greater efficiency in sensing sensitivity by using process simulation with CST STUDIO Suite software. In addition, Interdigital Transducer (IDT) parameters also changed to be created the products with a smaller size and easy to handle where it also reduces the cost of this product. Parameter values of an Interdigital Transducer (IDT) will be changed in the design is the total number of fingers pair, finger length, finger width and spacing, aperture and also the thickness of the Interdigital Transducer (IDT). From the result, the performance of the sensor is improved significantly after modification is done.

  14. The SSG Wave Energy Converter: Performance, Status and Recent Developments

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Margheritini, Lucia; Kofoed, Jens Peter

    2012-01-01

    through turbines for electricity production. The system utilizes a wide spectrum of different wave conditions by means of multiple reservoirs, located at different levels above the still water level. Thereby, it obtains a high overall efficiency and it can be suitable for shoreline and breakwater...... applications, presenting particular advantages such as: sharing structure costs, availability of grid connection and infrastructures, recirculation of water inside the harbor, as the outlet of the turbines is on the rear part of the system. Recently, plans for the SSG pilot installation were in progress...... on wave loadings and on hydraulic performances (overtopping and reflection) in order to optimize the structure design. This paper addresses the influence of various parameters (geometry, wave characteristics) on overtopping, reflection and wave loading and it draws conclusions on performances...

  15. Experimentally Based Model to Size the Geometry of a New OWC Device, with Reference to the Mediterranean Sea Wave Environment

    Directory of Open Access Journals (Sweden)

    Piero Ruol

    2013-09-01

    Full Text Available This note presents the Seabreath wave energy converter, basically a multi-chamber floating oscillating water column device, and the lumped model used to size its chambers, the ducts and the turbine. The model is based on extensive testing carried out in the wave flume of the University of Padova using fixed and floating models with a dummy power take off and indirect measurement of the produced power. A map with the available energy in the Mediterranean Sea is also proposed, showing possible ideal application sites. The Seabreath is finally dimensioned for a quarter scale test application in the Adriatic Sea, with a 3 kW turbine, and a capacity factor of 40%.

  16. The Contribution of Environmental Siting and Permitting Requirements to the Cost of Energy for Wave Energy Devices

    Energy Technology Data Exchange (ETDEWEB)

    Copping, Andrea E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Geerlofs, Simon H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hanna, Luke A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-06-01

    Responsible deployment of marine and hydrokinetic (MHK) devices in estuaries, coastal areas, and major rivers requires that biological resources and ecosystems be protected through siting and permitting (consenting) processes. Scoping appropriate deployment locations, collecting pre-installation (baseline) and post-installation data all add to the cost of developing MHK projects, and hence to the cost of energy. Under the direction of the U.S. Department of Energy, Pacific Northwest National Laboratory scientists have developed logic models that describe studies and processes for environmental siting and permitting. Each study and environmental permitting process has been assigned a cost derived from existing and proposed tidal, wave, and riverine MHK projects. Costs have been developed at the pilot scale and for commercial arrays for a surge wave energy converter

  17. Total Ionizing Dose Effects on Threshold Switching in 1T-Tantalum Disulfide Charge-Density-Wave Devices

    OpenAIRE

    Liu, G.; Zhang, E. X.; Liang, C. D.; Bloodgood, M. A.; Salguero, T. T.; Fleetwood, D. M.; Balandin, A. A.

    2017-01-01

    The 1T polytype of TaS2 exhibits voltage-triggered threshold switching as a result of a phase transition from nearly commensurate to incommensurate charge density wave states. Threshold switching, persistent above room temperature, can be utilized in a variety of electronic devices, e.g., voltage controlled oscillators. We evaluated the total-ionizing-dose response of thin film 1T-TaS2 at doses up to 1 Mrad(SiO2). The threshold voltage changed by less than 2% after irradiation, with persisten...

  18. The Contribution of Environmental Siting and Permitting Requirements to the Cost of Energy for Oscillating Water Column Wave Energy Devices

    Energy Technology Data Exchange (ETDEWEB)

    Copping, Andrea E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Geerlofs, Simon H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hanna, Luke A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-09-01

    Responsible deployment of marine and hydrokinetic (MHK) devices in estuaries, coastal areas, and major rivers requires that biological resources and ecosystems be protected through siting and permitting (consenting) processes. Scoping appropriate deployment locations, collecting pre-installation (baseline) and post-installation data all add to the cost of developing MHK projects, and hence to the cost of energy. Under the direction of the U.S. Department of Energy, Pacific Northwest National Laboratory scientists have developed logic models that describe studies and processes for environmental siting and permitting. Each study and environmental permitting process has been assigned a cost derived from existing and proposed tidal, wave, and riverine MHK projects, as well as expert opinion of marine environmental research professionals. Cost estimates have been developed at the pilot and commercial scale. The reference model described in this document is an oscillating water column device deployed in Northern California at approximately 50 meters water depth.

  19. Development of a combined surface plasmon resonance/surface acoustic wave device for the characterization of biomolecules

    International Nuclear Information System (INIS)

    Bender, Florian; Tsortos, Achilleas; Papadakis, George; Gizeli, Electra; Roach, Paul; Newton, Michael I; McHale, Glen

    2009-01-01

    It is known that acoustic sensor devices, if operated in liquid phase, are sensitive not just to the mass of the analyte but also to various other parameters, such as size, shape, charge and elastic constants of the analyte as well as bound and viscously entrained water. This can be used to extract valuable information about a biomolecule, particularly if the acoustic device is combined with another sensor element which is sensitive to the mass or amount of analyte only. The latter is true in good approximation for various optical sensor techniques. This work reports on the development of a combined surface plasmon resonance/surface acoustic wave sensor system which is designed for the investigation of biomolecules such as proteins or DNA. Results for the deposition of neutravidin and DNA are reported

  20. On the use of the fictitious wave steepness and related surf-similarity parameters in methods that describe the hydraulic and structural response to waves

    NARCIS (Netherlands)

    Heineke, D.; Verhagen, H.J.

    2007-01-01

    To assess the hydraulic performance of coastal structures - viz. wave run-up, overtopping and reflection - and to evaluate the stability of the armour layers, use is made of the dimensionless surf similarity parameter, as introduced by Battjes (1974). The front side slope of the structure and the

  1. Isolation of gravitational waves from displacement noise and utility of a time-delay device

    Energy Technology Data Exchange (ETDEWEB)

    Somiya, Kentaro [Max-Planck Institut fuer Gravitationsphysik, Am Muehlenberg 1, 14476 Potsdam (Germany); Goda, Keisuke [LIGO Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Chen, Yanbei [Max-Planck Institut fuer Gravitationsphysik, Am Muehlenberg 1, 14476 Potsdam (Germany); Mikhailov, Eugeniy E [Department of Physics, College of William and Mary, Williamsburg, VA 23187 (United States)

    2007-05-15

    Interferometers with kilometer-scale arms have been built for gravitational-wave detections on the ground; ones with much longer arms are being planned for space-based detection. One fundamental motivation for long baseline interferometry is from displacement noise. In general, the longer the arm length L, the larger the motion the gravitational-wave induces on the test masses, until L becomes comparable to the gravitational wavelength. Recently, schemes have been invented, in which displacement noise can be evaded by employing differences between the influence of test-mass motions and that of gravitational waves on light propagation. However, in these schemes, such differences only becomes significant when Lapproaches the gravitational wavelength. In this paper, we explore a use of artificial time delay in displacement-noise-free interferometers, which will shift the frequency band of the effect being significant and may improve their shot-noise-limited sensitivity at low frequencies.

  2. Isolation of gravitational waves from displacement noise and utility of a time-delay device

    International Nuclear Information System (INIS)

    Somiya, Kentaro; Goda, Keisuke; Chen, Yanbei; Mikhailov, Eugeniy E

    2007-01-01

    Interferometers with kilometer-scale arms have been built for gravitational-wave detections on the ground; ones with much longer arms are being planned for space-based detection. One fundamental motivation for long baseline interferometry is from displacement noise. In general, the longer the arm length L, the larger the motion the gravitational-wave induces on the test masses, until L becomes comparable to the gravitational wavelength. Recently, schemes have been invented, in which displacement noise can be evaded by employing differences between the influence of test-mass motions and that of gravitational waves on light propagation. However, in these schemes, such differences only becomes significant when Lapproaches the gravitational wavelength. In this paper, we explore a use of artificial time delay in displacement-noise-free interferometers, which will shift the frequency band of the effect being significant and may improve their shot-noise-limited sensitivity at low frequencies

  3. The phase accumulation and antenna near field of microscopic propagating spin wave devices

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Crosby S.; Kostylev, Mikhail, E-mail: mikhail.kostylev@uwa.edu.au; Ivanov, Eugene [School of Physics M013, The University of Western Australia, Crawley, WA 6009 (Australia); Ding, Junjia; Adeyeye, Adekunle O. [Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore (Singapore)

    2014-01-20

    We studied phase accumulation by the highly non-reciprocal magnetostatic surface spin waves in thin Permalloy microstripes excited and received by microscopic coplanar antennae. We find that the experimentally measured characteristic length of the near field of the antenna is smaller than the total width of the coplanar. This is confirmed by our numerical simulations. Consequently, the distance over which the spin wave accumulates its phase while travelling between the input and output antennae coincides with the distance between the antennae symmetry axes with good accuracy.

  4. The phase accumulation and antenna near field of microscopic propagating spin wave devices

    International Nuclear Information System (INIS)

    Chang, Crosby S.; Kostylev, Mikhail; Ivanov, Eugene; Ding, Junjia; Adeyeye, Adekunle O.

    2014-01-01

    We studied phase accumulation by the highly non-reciprocal magnetostatic surface spin waves in thin Permalloy microstripes excited and received by microscopic coplanar antennae. We find that the experimentally measured characteristic length of the near field of the antenna is smaller than the total width of the coplanar. This is confirmed by our numerical simulations. Consequently, the distance over which the spin wave accumulates its phase while travelling between the input and output antennae coincides with the distance between the antennae symmetry axes with good accuracy

  5. Wave Induced Stresses Measured at the Wave Dragon Nissum Bredning Prototype

    DEFF Research Database (Denmark)

    Corona, L.; Kofoed, Jens Peter

    2006-01-01

    The paper describes the wave induced loading on the overtopping based wave energy converter Wave Dragon. Focus is put on the junction between the main body and the reflector, also called the "shoulder part", where large cross sectional forces and bending moments acts. There are two main objectives...... for this paper, first to verify the FEM results obtained by Niras, Danish society in charge of the finite element modelling and structural design, and then to make a first experimental fatigue analysis of a particular part of the Wave Dragon. This last part shall be considered as an exercise for the further work...

  6. Over-the-air Radiated Testing of Millimeter-Wave Beam-steerable Devices in a Cost-Effective Measurement Setup

    DEFF Research Database (Denmark)

    Fan, Wei; Kyösti, Pekka; Rumney, Moray

    2018-01-01

    antenna selection scheme is proposed. This setup is suitable for evaluation of beam-steerable devices, including both base station (BS) and user equipment (UE) devices. The requirements for the test system design are analyzed, including the measurement range, number of OTA antennas, number of active OTA...... conditions. In this article, radiated testing methods are reviewed, with a focus on their principle and applicability for beam steerable mmWave devices. To explore the spatial sparsity of mmWave channel profiles, a cost-effective simplified 3D sectored multi-probe anechoic chamber (MPAC) system with an OTA......With the severe spectrum congestion of sub-6GHz cellular systems, large-scale antenna systems in the millimeter-wave (mmWave) bands can potentially meet the high data rate envisioned for fifth generation (5G) communications. Performance evaluation of antenna systems is an essential step...

  7. Analysis of transient electromagnetic wave interactions on graphene-based devices using integral equations

    KAUST Repository

    Shi, Yifei

    2015-10-26

    Graphene is a monolayer of carbon atoms structured in the form of a honeycomb lattice. Recent experimental studies have revealed that it can support surface plasmons at Terahertz frequencies thanks to its dispersive conductivity. Additionally, characteristics of these plasmons can be dynamically adjusted via electrostatic gating of the graphene sheet (K. S. Novoselov, et al., Science, 306, 666–669, 2004). These properties suggest that graphene can be a building block for novel electromagnetic and photonic devices for applications in the fields of photovoltaics, bio-chemical sensing, all-optical computing, and flexible electronics. Simulation of electromagnetic interactions on graphene-based devices is not an easy task. The thickness of the graphene sheet is orders of magnitude smaller than any other geometrical dimension of the device. Consequently, discretization of such a device leads to significantly large number of unknowns and/or ill-conditioned matrix systems.

  8. Frequency response improvement of a two-port surface acoustic wave device based on epitaxial AlN thin film

    Science.gov (United States)

    Gao, Junning; Hao, Zhibiao; Luo, Yi; Li, Guoqiang

    2018-01-01

    This paper presents an exploration on improving the frequency response of the symmetrical two-port AlN surface acoustic wave (SAW) device, using epitaxial AlN thin film on (0001) sapphire as the piezoelectric substrate. The devices were fabricated by lift-off processes with Ti/Al composite electrodes as interleaved digital transducers (IDT). The impact of DL and the number of the IDT finger pairs on the frequency response was carefully investigated. The overall properties of the device are found to be greatly improved with DL elongation, indicated by the reduced pass band ripple and increased stop band rejection ratio. The rejection increases by 8.3 dB when DL elongates from 15.5λ to 55.5λ and 4.4 dB further accompanying another 50λ elongation. This is because larger DL repels the stray acoustic energy out of the propagation path and provides a cleaner traveling channel for functional SAW, and at the same time restrains electromagnetic feedthrough. It is also found that proper addition of the IDT finger pairs is beneficial for the device response, indicated by the ripple reduction and the insertion loss drop.

  9. Separation of density and viscosity influence on liquid-loaded surface acoustic wave devices

    Science.gov (United States)

    Herrmann, F.; Hahn, D.; Büttgenbach, S.

    1999-05-01

    Love-mode sensors are reported for separate measurement of liquid density and viscosity. They combine the general merits of Love-mode devices, e.g., ease of sensitivity adjustment and robustness, with a highly effective procedure of separate determination of liquid density and viscosity. A model is proposed to describe the frequency response of the devices to liquid loading. Moreover, design rules are given for further optimization and sensitivity enhancement.

  10. Counterpropagating wave acoustic particle manipulation device for the effective manufacture of composite materials.

    Science.gov (United States)

    Scholz, Marc-S; Drinkwater, Bruce W; Llewellyn-Jones, Thomas M; Trask, Richard S

    2015-10-01

    An ultrasonic assembly device exhibiting broadband behavior and a sacrificial plastic frame is described. This device is used to assemble a variety of microscopic particles differing in size, shape, and material into simple patterns within several host fluids. When the host fluid is epoxy, the assembled materials can be cured and the composite sample extracted from the sacrificial frame. The wideband performance means that within a single device, the wavelength can be varied, leading to control of the length scale of the acoustic radiation force field. We show that glass fibers of 50 μm length and 14 μm diameter can be assembled into a series of stripes separated by hundreds of microns in a time of 0.3 s. Finite element analysis is used to understand the attributes of the device which control its wideband characteristics. The bandwidth is shown to be governed by the damping produced by a combination of the plastic frame and the relatively large volume of the fluid particle mixture. The model also reveals that the acoustic radiation forces are a maximum near the substrate of the device, which is in agreement with experimental observations. The device is extended to 8-transducers and used to assemble more complex particle distributions.

  11. Wave

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    2008-01-01

    Estimates for the amount of potential wave energy in the world range from 1-10 TW. The World Energy Council estimates that a potential 2TW of energy is available from the world’s oceans, which is the equivalent of twice the world’s electricity production. Whilst the recoverable resource is many...... times smaller it remains very high. For example, whilst there is enough potential wave power off the UK to supply the electricity demands several times over, the economically recoverable resource for the UK is estimated at 25% of current demand; a lot less, but a very substantial amount nonetheless....

  12. Wave-actuated power take-off device for electricity generation

    Energy Technology Data Exchange (ETDEWEB)

    Chertok, Allan

    2013-01-31

    Since 2008, Resolute Marine Energy, Inc. (RME) has been engaged in the development of a rigidly moored shallow-water point absorber wave energy converter, the "3D-WEC". RME anticipated that the 3D-WEC configuration with a fully buoyant point absorber buoy coupled to three power take off (PTO) units by a tripod array of tethers would achieve higher power capture than a more conventional 1-D configuration with a single tether and PTO. The investigation conducted under this program and documented herein addressed the following principal research question regarding RME's power take off (PTO) concept for its 3D-WEC: Is RME's winch-driven generator PTO concept, previously implemented at sub-scale and tested at the Ohmsett wave tank facility, scalable in a cost-effective manner to significant power levels e.g., 10 to 100kW?

  13. Comparison of Walking and Traveling-Wave Piezoelectric Motors as Actuators in Kinesthetic Haptic Devices.

    Science.gov (United States)

    Olsson, Pontus; Nysjo, Fredrik; Carlbom, Ingrid B; Johansson, Stefan

    2016-01-01

    Piezoelectric motors offer an attractive alternative to electromagnetic actuators in portable haptic interfaces: they are compact, have a high force-to-volume ratio, and can operate with limited or no gearing. However, the choice of a piezoelectric motor type is not obvious due to differences in performance characteristics. We present our evaluation of two commercial, operationally different, piezoelectric motors acting as actuators in two kinesthetic haptic grippers, a walking quasi-static motor and a traveling wave ultrasonic motor. We evaluate each gripper's ability to display common virtual objects including springs, dampers, and rigid walls, and conclude that the walking quasi-static motor is superior at low velocities. However, for applications where high velocity is required, traveling wave ultrasonic motors are a better option.

  14. Control-Informed Geometric Optimization of Wave Energy Converters: The Impact of Device Motion and Force Constraints

    Directory of Open Access Journals (Sweden)

    Paula B. Garcia-Rosa

    2015-12-01

    Full Text Available The energy cost for producing electricity via wave energy converters (WECs is still not competitive with other renewable energy sources, especially wind energy. It is well known that energy maximising control plays an important role to improve the performance of WECs, allowing the energy conversion to be performed as economically as possible. The control strategies are usually subsequently employed on a device that was designed and optimized in the absence of control for the prevailing sea conditions in a particular location. If an optimal unconstrained control strategy, such as pseudo-spectral optimal control (PSOC, is adopted, an overall optimized system can be obtained no matter whether the control design is incorporated at the geometry optimization stage or not. Nonetheless, strategies, such as latching control (LC, must be incorporated at the optimization design stage of the WEC geometry if an overall optimized system is to be realised. In this paper, the impact of device motion and force constraints in the design of control-informed optimized WEC geometries is addressed. The aim is to verify to what extent the constraints modify the connection between the control and the optimal device design. Intuitively, one might expect that if the constraints are very tight, the optimal device shape is the same regardless of incorporating or not the constrained control at the geometry optimization stage. However, this paper tests the hypothesis that the imposition of constraints will limit the control influence on the optimal device shape. PSOC, LC and passive control (PC are considered in this study. In addition, constrained versions of LC and PC are presented.

  15. On generation of Alfvenic-like fluctuations by drift wave-zonal flow system in large plasma device experiments

    International Nuclear Information System (INIS)

    Horton, W.; Correa, C.; Chagelishvili, G. D.; Avsarkisov, V. S.; Lominadze, J. G.; Perez, J. C.; Kim, J.-H.; Carter, T. A.

    2009-01-01

    According to recent experiments, magnetically confined fusion plasmas with ''drift wave-zonal flow turbulence'' (DW-ZF) give rise to broadband electromagnetic waves. Sharapov et al. [Europhysics Conference Abstracts, 35th EPS Conference on Plasma Physics, Hersonissos, 2008, edited by P. Lalousis and S. Moustaizis (European Physical Society, Switzerland, 2008), Vol. 32D, p. 4.071] reported an abrupt change in the magnetic turbulence during L-H transitions in Joint European Torus [P. H. Rebut and B. E. Keen, Fusion Technol. 11, 13 (1987)] plasmas. A broad spectrum of Alfvenic-like (electromagnetic) fluctuations appears from ExB flow driven turbulence in experiments on the large plasma device (LAPD) [W. Gekelman et al., Rev. Sci. Instrum. 62, 2875 (1991)] facility at UCLA. Evidence of the existence of magnetic fluctuations in the shear flow region in the experiments is shown. We present one possible theoretical explanation of the generation of electromagnetic fluctuations in DW-ZF systems for an example of LAPD experiments. The method used is based on generalizing results on shear flow phenomena from the hydrodynamics community. In the 1990s, it was realized that fluctuation modes of spectrally stable nonuniform (sheared) flows are non-normal. That is, the linear operators of the flows modal analysis are non-normal and the corresponding eigenmodes are not orthogonal. The non-normality results in linear transient growth with bursts of the perturbations and the mode coupling, which causes the generation of electromagnetic waves from the drift wave-shear flow system. We consider shear flow that mimics tokamak zonal flow. We show that the transient growth substantially exceeds the growth of the classical dissipative trapped-particle instability of the system.

  16. Study of ICRF wave propagation and plasma coupling efficiency in a linear magnetic mirror device

    International Nuclear Information System (INIS)

    Peng, S.Y.

    1991-07-01

    Ion Cyclotron Range of Frequency (ICRF) wave propagation in an inhomogeneous axial magnetic field in a cylindrical plasma-vacuum system has historically been inadequately modelled. Previous works either sacrifice the cylindrical geometry in favor of a simpler slab geometry, concentrate on the resonance region, use a single mode to represent the entire field structure, or examine only radial propagation. This thesis performs both analytical and computational studies to model the ICRF wave-plasma coupling and propagation problem. Experimental analysis is also conducted to compare experimental results with theoretical predictions. Both theoretical as well as experimental analysis are undertaken as part of the thesis. The theoretical studies simulate the propagation of ICRF waves in an axially inhomogeneous magnetic field and in cylindrical geometry. Two theoretical analysis are undertaken - an analytical study and a computational study. The analytical study treats the inhomogeneous magnetic field by transforming the (r,z) coordinate into another coordinate system (ρ,ξ) that allows the solution of the fields with much simpler boundaries. The plasma fields are then Fourier transformed into two coupled convolution-integral equations which are then differenced and solved for both the perpendicular mode number α as well as the complete EM fields. The computational study involves a multiple eigenmode computational analysis of the fields that exist within the plasma-vacuum system. The inhomogeneous axial field is treated by dividing the geometry into a series of transverse axial slices and using a constant dielectric tensor in each individual slice. The slices are then connected by longitudinal boundary conditions

  17. Development of a flexible and bendable vibrotactile actuator based on wave-shaped poly(vinyl chloride)/acetyl tributyl citrate gels for wearable electronic devices

    Science.gov (United States)

    Park, Won-Hyeong; Bae, Jin Woo; Shin, Eun-Jae; Kim, Sang-Youn

    2016-11-01

    The paradigm of consumer electronic devices is being shifted from rigid hand-held devices to flexible/wearable devices in search of benefits such as enhanced usability and portability, excellent wear characteristics, and more functions in less space. However, the fundamental incompatibility of flexible/wearable devices and a rigid actuator brought forth a new issue obstructing commercialization of flexible/wearable devices. In this paper, we propose a new wave-shaped eco-friendly PVC gel, and a new flexible and bendable vibrotactile actuator that could easily be applied to wearable electronic devices. We explain the vibration mechanism of the proposed vibrotactile actuator and investigate its influence on the content of plasticizer for the performance of the proposed actuator. An experiment for measuring vibrational amplitude was conducted over a wide frequency range. The experiment clearly showed that the proposed vibrotactile actuator could create a variety of haptic sensations in wearable devices.

  18. Pulse Wave Velocity Measuring System using Virtual Instrumentation on Mobile Device

    Directory of Open Access Journals (Sweden)

    Razvan Alin Ciobotariu

    2013-03-01

    Full Text Available Virtual instrumentation is a concept that permits customizable modular software measurement and the development of the user-defined tools for control, process and visualization of data, creating versatile systems, using modular programming, intuitive and easy to use. In this paper we investigate a possibility of using virtual instrumentation in the development of two physiological parameters monitoring system, in order to assess a cardiovascular parameter, the Pulse Wave Velocity (PWV. We choose to monitor this parameter due to major incidence and impact of cardiovascular diseases (CVD.

  19. Parametrics for Molecular Deuterium Concentrations in the Source Region of the UW-IEC Device Using an Ion Acoustic Wave Diagnostic

    Science.gov (United States)

    Boris, D. R.; Emmert, G. A.

    2007-11-01

    The ion source region of the UW-Inertial Electrostatic Confinement device is comprised of a filament assisted DC discharge plasma that exists between the wall of the IEC vacuum chamber and the grounded spherical steel grid that makes up the anode of the IEC device. A 0-dimensional rate equation calculation of the molecular deuterium ion species concentration has been applied utilizing varying primary electron energy, and neutral gas pressure. By propagating ion acoustic waves in the source region of the IEC device the concentrations of molecular deuterium ion species have been determined for these varying plasma conditions, and high D3^+ concentrations have been verified. This was done by utilizing the multi-species ion acoustic wave dispersion relation, which relates the phase speed of the multi-species ion acoustic wave, vph, to the sum in quadrature of the concentration weighted ion acoustic sound speeds of the individual ion species.

  20. Quasi-optic millimeter-wave device application of liquid crystal material by using porous PMMA matrix

    Science.gov (United States)

    Nose, T.; Watanabe, Y.; Kon, A.; Ito, R.; Honma, M.

    2018-02-01

    Recently, millimeter-waves (MMWs) have become indispensable for application in next-generation high-speed wireless communication i.e., 5G, in addition to conventional applications such as in automobile collision avoidance radars and airport security inspection systems. Some manageable devices to control MMW propagation will be necessary with the development of this new technology field. We believe that liquid crystal (LC) devices are one of the major candidates for such applications because it is known that LC materials are excellent electro-optic materials. However, as the wavelength of MMWs is extremely longer than the optics region, extremely thick LC layers are necessary if we choose the quasioptic approach to attain LC MMW control devices. Therefore, we adopt a PDLC structure to attain the extremely thick LC layers by using porous (polymethyl methacrylate) PMMA materials, which can be easily obtained using a solvent consisting of a mixture of ethanol/water and a little heating. In this work, we focus on Fresnel lens, which is an important quasi-optic device for MMW application, to introduce a tunable property by using LC materials. Here, we adopt the thin film deposition method to obtain a porous PMMA matrix with the aim of obtaining final composite structure based on the Fresnel substrate. First, the fundamental material properties of porous PMMA are investigated to control the microscopic porous structure. Then, the LC-MMW Fresnel lens substrate is prepared using a 3D printer, and the fundamental MMW focusing properties of the prototype composite Fresnel structure are investigated.

  1. Electronic defect levels in continuous wave laser annealed silicon metal oxide semiconductor devices

    Science.gov (United States)

    Cervera, M.; Garcia, B. J.; Martinez, J.; Garrido, J.; Piqueras, J.

    1988-09-01

    The effect of laser treatment on the bulk and interface states of the Si-SiO2 structure has been investigated. The annealing was performed prior to the gate metallization using a continuous wave Ar+ laser. For low laser powers the interface state density seems to decrease slightly in comparison with untreated samples. However, for the highest irradiating laser powers a new bulk level at 0.41 eV above the valence band with concentrations up to 1015 cm-3 arises probably due to the electrical activation of the oxygen diluted in the Czochralski silicon. Later postmetallization annealings reduce the interface state density to values in the 1010 cm-2 eV-1 range but leave the concentration of the 0.41-eV center nearly unchanged.

  2. Theoretical aspects of the electronical devices operating due to interaction between annular electron beams and the azimuthal surface waves

    Energy Technology Data Exchange (ETDEWEB)

    Girka, V O; Girka, I O [Kharkiv State Univ. (Ukraine)

    1997-12-31

    The physical basis is discussed of electronic devices whose operation is based on the beam or dissipative instability of the azimuthal surface waves (ASW). The ASW are electromagnetic surface waves with extraordinary polarization (with field components E{sub r}, E{sub {phi}}, H{sub z}), propagating across the axial external steady magnetic field in the cylindrical metal waveguide with cold plasma filling. The ASW fields are described by Maxwell equations. To solve the problem, the authors used the Fourier method and numerical simulation of the equations obtained. The ASW excitation was examined under conditions of beam and dissipative instabilities due to the electron beam motion. The correction to ASW eigenfrequencies caused by the waveguide chamber noncircularity was also studied. ASW delaying leads to a negative frequency correction. The ASW energy can be emitted from the narrow slot in the metallic chamber of the waveguide. The optimum wavenumber range was found where the increment values are much greater than those of the ASW decrement caused by their energy radiation. (author). 2 figs., 3 refs.

  3. Chemical etching of Tungsten thin films for high-temperature surface acoustic wave-based sensor devices

    Energy Technology Data Exchange (ETDEWEB)

    Spindler, M., E-mail: m.spindler@ifw-dresden.de [IFW Dresden, SAWLab Saxony, P.O. Box 270116, D-01171 Dresden (Germany); Herold, S.; Acker, J. [BTU Cottbus – Senftenberg, Faculty of Sciences, P.O. Box 101548, 01968 Senftenberg (Germany); Brachmann, E.; Oswald, S.; Menzel, S.; Rane, G. [IFW Dresden, SAWLab Saxony, P.O. Box 270116, D-01171 Dresden (Germany)

    2016-08-01

    Surface acoustic wave devices are widely used as wireless sensors in different application fields. Recent developments aimed to utilize those devices as temperature sensors even in the high temperature range (T > 300 °C) and in harsh environmental conditions. Therefore, conventional materials, which are used for the substrate and for the interdigital transducer finger electrodes such as multilayers or alloys based on Al or Cu have to be exchanged by materials, which fulfill some important criteria regarding temperature related effects. Electron beam evaporation as a standard fabrication method is not well applicable for depositing high temperature stable electrode materials because of their very high melting points. Magnetron sputtering is an alternative deposition process but is also not applicable for lift-off structuring without any further improvement of the structuring process. Due to a relatively high Ar gas pressure of about 10{sup −1} Pa, the sidewalls of the photoresist line structures are also covered by the metallization, which subsequently prevents a successful lift-off process. In this study, we investigate the chemical etching of thin tungsten films as an intermediate step between magnetron sputtering deposition of thin tungsten finger electrodes and the lift-off process to remove sidewall covering for a successful patterning process of interdigital transducers. - Highlights: • We fabricated Tungsten SAW Electrodes by magnetron sputtering technology. • An etching process removes sidewall covering of photoresist, which allows lift-off. • Tungsten etching rates based on a hydrogen peroxide solutions were determined.

  4. Integration of BST varactors with surface acoustic wave device by film transfer technology for tunable RF filters

    International Nuclear Information System (INIS)

    Hirano, Hideki; Tanaka, Shuji; Kimura, Tetsuya; Koutsaroff, Ivoyl P; Kadota, Michio; Hashimoto, Ken-ya; Esashi, Masayoshi

    2013-01-01

    This paper presents a film transfer process to integrate barium strontium titanate (BST) metal–insulator–metal (MIM) structures with surface acoustic wave (SAW) devices on a lithium niobate (LN) substrate. A high-quality BST film grown on a Si substrate above 650 °C was patterned into the MIM structures, and transferred to a LN substrate below 130 °C by Ar-plasma-activated Au–Au bonding and the Si lost wafer process. Simple test SAW devices with the transferred BST variable capacitors (VCs) were fabricated and characterized. The resonance frequency of a one-port SAW resonator with the VC connected in series changed from 999 to 1018 MHz, when a dc bias voltage of 3 V was applied to the VC. Although the observed frequency tuning range was smaller than expected due to the degradation of BST in the process, the experimental result demonstrated that a tunable SAW filter with the transferred BST VCs was feasible. (paper)

  5. Carbon nanotubes/ceria composite layers deposited on surface acoustic wave devices for gas detection at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    David, M., E-mail: marjorie.david@univ-tln.fr [Universite du Sud Toulon, Var, IM2NP, UMR CNRS 6242, BP 20132. F 83 957 LA GARDE (France); Arab, M.; Martino, C. [Universite du Sud Toulon, Var, IM2NP, UMR CNRS 6242, BP 20132. F 83 957 LA GARDE (France); Delmas, L. [SENSeOR, Sophia Antipolis, 06250 Mougins (France); Guinneton, F.; Gavarri, J.-R. [Universite du Sud Toulon, Var, IM2NP, UMR CNRS 6242, BP 20132. F 83 957 LA GARDE (France)

    2012-05-01

    Surface acoustic wave (SAW) sensor on ATquartz piezoelectric substrate has been designed and fabricated. Test devices were based on asynchronous single-port resonators operating near the 434-MHz-centered industrial, scientific, and medical band. Multi-Walled Carbon Nanotubes/Ceria (MWNTs/CeO{sub 2}) nanocomposites were used as sensitive layers. The MWNTs were synthesized by catalytic chemical vapor deposition method and coated with nanosized ceria oxide. The composites were deposited on SAW quartz resonator using air-brush technique. MWNTs/CeO{sub 2} nanocomposites were characterized using X-ray diffraction, transmission electron and atomic force microscopy. The sensor responses were tested under acetone (C{sub 3}H{sub 5}OH) and ethanol (C{sub 2}H{sub 5}OH) gases. The output signal was done by S{sub 11} parameter of the SAW device and was monitored using a network analyzer. Frequency changes were observed under acetone and ethanol vapors. These changes depended on the surface conductivity of the nanocomposites deposited on the sensor. The single-port SAW gas sensor coated with the MWNTs/CeO{sub 2} presented the highest sensitivity in the case of acetone vapor interacting with these layers, with a frequency shift of 200 kHz at room temperature.

  6. Electrically switchable photonic liquid crystal devices for routing of a polarized light wave

    Science.gov (United States)

    Rushnova, Irina I.; Melnikova, Elena A.; Tolstik, Alexei L.; Muravsky, Alexander A.

    2018-04-01

    The new mode of LC alignment based on photoalignment AtA-2 azo dye where the refractive interface between orthogonal orientations of the LC director exists without voltage and disappeared or changed with critical voltage has been proposed. The technology to fabricate electrically controlled liquid crystal elements for spatial separation and switching of linearly polarized light beams on the basis of the total internal reflection effect has been significantly improved. Its distinctive feature is the application of a composite alignment material comprising two sublayers of Nylon-6 and AtA-2 photoalignment azo dye offering patterned liquid crystal director orientation with high alignment quality value q = 0 . 998. The fabricated electrically controlled spatially structured liquid crystal devices enable implementation of propagation directions separation for orthogonally polarized light beams and their switching with minimal crosstalk.

  7. Opto-Electromechanical Devices for Low-Noise Detection of Radio Waves

    DEFF Research Database (Denmark)

    Bagci, Tolga

    factors. For example, a hybrid system like this, would enable the use of well-established shot-noise limited optical sensing technologies for detecting weak radio-frequency (rf) signals, rf-to-optical photon conversion and transmission of information in low-loss fiber-optic links over long distances......There is currently an increasing interest in developing hybrid devices that unite the desirable features of different systems. Opto-electromechanics has emerged as one of these promising hybrid fields, where the functionality of conventional electrical circuits can be combined with the salient...... features of optical systems for various technological and sensing applications. Nanomechanical resonators stand as promising candidates in terms of linking the two systems, primarily thanks to their versatility in coupling to various physical systems, together with their excellent mechanical quality...

  8. Comparison of the Complior Analyse device with Sphygmocor and Complior SP for pulse wave velocity and central pressure assessment.

    Science.gov (United States)

    Stea, Francesco; Bozec, Erwan; Millasseau, Sandrine; Khettab, Hakim; Boutouyrie, Pierre; Laurent, Stéphane

    2014-04-01

    The Complior device (Alam Medical, France) was used in epidemiological studies which established pulse wave velocity (PWV) as a cardiovascular risk marker. Central pressure is related, but complementary to PWV and also associated to cardiovascular outcomes. The new Complior Analyse measures both PWV and central blood pressure during the same acquisition. The aim of this study was to compare PWV values from Complior Analyse with the previous Complior SP (PWVcs) and with Sphygmocor (PWVscr; AtCor, Australia), and to compare central systolic pressure from Complior Analyse and Sphygmocor. Peripheral and central pressures and PWV were measured with the three devices in 112 patients. PWV measurements from Complior Analyse were analysed using two foot-detection algorithms (PWVca_it and PWVca_cs). Both radial (ao-SBPscr) and carotid (car-SBPscr) approaches from Sphygmocor were compared to carotid Complior Analyse measurements (car-SBPca). The same distance and same calibrating pressures were used for all devices. PWVca_it was strongly correlated to PWVscr (R(2) = 0.93, P < 0.001) with a difference of 0.0 ± 0.7  m/s. PWVca_cs was also correlated to PWVcs (R(2) = 0.90, P < 0.001) with a difference of 0.1 ± 0.7  m/s. Central systolic pressures were strongly correlated. The difference between car-SBPca and ao-SBPscr was 3.1 ± 4.2  mmHg (P < 0.001), statistically equivalent to the difference between car-SBPscr and ao-SBPscr (3.9 ± 5.8  mmHg, P < 0.001), whilst the difference between car-SBPca and car-SBPscr was negligible (-0.7 ± 5.6  mmHg, P = NS). The new Complior Analyse device provides equivalent results for PWV and central pressure values to the Sphygmocor and Complior SP. It reaches Association for the Advancement of Medical Instrumentation standard for central blood pressure and grades as excellent for PWV on the Artery Society criteria. It can be interchanged with existing devices.

  9. Fractional Ablative Laser Followed by Transdermal Acoustic Pressure Wave Device to Enhance the Drug Delivery of Aminolevulinic Acid: In Vivo Fluorescence Microscopy Study.

    Science.gov (United States)

    Waibel, Jill S; Rudnick, Ashley; Nousari, Carlos; Bhanusali, Dhaval G

    2016-01-01

    Topical drug delivery is the foundation of all dermatological therapy. Laser-assisted drug delivery (LAD) using fractional ablative laser is an evolving modality that may allow for a greater precise depth of penetration by existing topical medications, as well as more efficient transcutaneous delivery of large drug molecules. Additional studies need to be performed using energy-driven methods that may enhance drug delivery in a synergistic manner. Processes such as iontophoresis, electroporation, sonophoresis, and the use of photomechanical waves aid in penetration. This study evaluated in vivo if there is increased efficacy of fractional CO2 ablative laser with immediate acoustic pressure wave device. Five patients were treated and biopsied at 4 treatment sites: 1) topically applied aminolevulinic acid (ALA) alone; 2) fractional ablative CO2 laser and topical ALA alone; 3) fractional ablative CO2 laser and transdermal acoustic pressure wave device delivery system; and 4) topical ALA with transdermal delivery system. The comparison of the difference in the magnitude of diffusion with both lateral spread of ALA and depth diffusion of ALA was measured by fluorescence microscopy. For fractional ablative CO2 laser, ALA, and transdermal acoustic pressure wave device, the protoporphyrin IX lateral fluorescence was 0.024 mm on average vs 0.0084 mm for fractional ablative CO2 laser and ALA alone. The diffusion for the acoustic pressure wave device was an order of magnitude greater. We found that our combined approach of fractional ablative CO2 laser paired with the transdermal acoustic pressure wave device increased the depth of penetration of ALA.

  10. On the acoustic wave sensor response to immortalized hypothalamic neurons at the device-liquid interface

    Directory of Open Access Journals (Sweden)

    Shilin Cheung

    2016-12-01

    Full Text Available The response of a thickness shear mode biosensor to immortalized murine hypothalamic neurons (mHypoE-38 and -46 cells under a variety of conditions and stimuli is discussed. Cellular studies which lead to the production of detectable neuronal responses include neuronal deposition, adhesion and proliferation, alteration in the extent of specific cell-surface interactions, actin filament and microtubule cytoskeletal disruptions, effects of cell depolarization, inhibition of the Na+-K+ pump via ouabain, effects of neuronal synchronization and the effects ligand-receptor interaction (glucagon. In the presence of cells, fs shifts are largely influenced by the damping of the TSM resonator. The formation of cell-surface interactions and hence the increase in coupling and acoustic energy dissipation can be modeled as an additional resistor in the BVD model. Further sensor and cellular changes can be obtained by negating the effects of damping from fs via the use of Rm and θmax. Keywords: Acoustic wave sensor, Hypothalamic neurons, Neuron cell-surface interaction

  11. A formula for efficiency of fast wave current drive in fusion devices

    International Nuclear Information System (INIS)

    Chiu, S.C.; Harvey, R.W.; Karney, C.F.F.; Mau, T.K.

    1992-06-01

    Fast wave current drive (FWCD) is a principal candidate for non- inductive current drive schemes in reactors. Major experiments are in progress or planned on DIII-D, JET, and Tore-Supra. A theory for FWCD was presented by two of the authors and collaborators. To minimize computations required in transport simulations, and for analytical understanding, it is very useful to have a concise analytical efficiency formula. Fisch and Karney, and Ehst and Karney have obtained empirical formulae that fits numerical results for the Landau limit and Alfven limit; the latter fits results at 1 i ≤ 2. This paper extends a previous numerical study on FWCD at arbitrary frequencies and Z i . Analytical formulae for FWCD efficiency, valid for all frequencies and Z i , are derived using the adjoint technique in high and low phase velocity regions. A smooth patching between the two regions produces an analytical formula which is accurate for all frequencies, Z i , and phase velocities. Comparison with existing results will be discussed. A corollary of the present calculation is that a low phase velocities and in the Landau limit, the efficiency is the same as that calculated from the Lorentz model collision operator

  12. Innovative rubble mound breakwaters for wave energy conversion

    International Nuclear Information System (INIS)

    Contestabile, Pasquale; Vicinanza, Diego; Iuppa, Claudio; Cavallaro, Luca; Foti, Enrico

    2015-01-01

    This paper presents a new Wave Energy Converter named Overtopping BReakwater for Energy Conversion (OBREC) which consists of a rubble mound breakwater with a front reservoir designed with the aim of capturing the wave overtopping in order to produce electricity. The energy is extracted via low head turbines, using the difference in water levels between the reservoir and the mean sea water level. The new design should be capable of adding a revenue generation function to a breakwater while adding cost sharing benefits due to integration. The design can be applied to harbour expansions, existing breakwater maintenance or upgrades due to climate change for a relatively low cost, considering the breakwater would be built regardless of the inclusion of a WEC [it

  13. Absorbing coatings for high power millimeter-wave devices and matched loads

    Energy Technology Data Exchange (ETDEWEB)

    Bin, W., E-mail: wbin@ifp.cnr.it [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Bruschi, A.; Cirant, S. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Muzzini, V. [Istituto di Biologia Agro-ambientale e Forestale, Consiglio Nazionale delle Ricerche, Area di Ricerca di Roma 1, Monterotondo, Rome (Italy); Simonetto, A.; Spinicchia, N. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Angella, G. [Istituto per l’Energetica e le Interfasi, Consiglio Nazionale delle Ricerche, Milano (Italy); Dell’Era, F. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Gantenbein, G.; Leonhardt, W. [Institut für Hochleistungsimpuls-und Mikrowellentechnik, Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Nardone, A. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Samartsev, A.; Schmid, M. [Institut für Hochleistungsimpuls-und Mikrowellentechnik, Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany)

    2013-10-15

    Highlights: ► An overview of the activity at IFP-CNR concerning the absorbing coatings is presented. ► The application of the absorbing ceramics to the IFP-CNR matched loads is described. ► B{sub 4}C is presented as a promising material for power absorption in the EC frequency range. ► The most important high power validation tests performed on coatings are described. ► Some results from simulations of the absorption capability of a double layer coating are shown. -- Abstract: In the electron cyclotron frequency range the handling of high power is critical. In some cases an unpredictable amount of stray radiation can reach some components or accumulate in localized regions, with risk of damages caused by thermal overloads, and any uncontrolled reflection represents a danger for the sources. A possibility to mitigate the problem consists in covering some regions exposed to radiation with absorbers. Enhanced absorption of stray radiation lowers requirements on active protection systems in microwave diagnostics. The released heat can be extracted by dedicated cooling systems. The chromium oxide (Cr{sub 2}O{sub 3}), largely tested at IFP-CNR, has been routinely used as internal coating for matched loads. The performances of a variable thickness coating has been tested at high power at Karlsruhe Institute of Technology (KIT), with a 140 GHz gyrotron of the W7-X ECRH system and an averaged power density absorbed at the coating surface higher than 1 MW/m{sup 2} for 3 min. Also boron carbide (B{sub 4}C) has been tested at low power and patented as a millimeter-wave absorber. In the paper, the results of some tests performed on these coatings are given, together with some simulations of the absorption capability based on low power measurements on samples. Finally, some calculations are presented for a coating obtained combining together Cr{sub 2}O{sub 3} and B{sub 4}C.

  14. Real-Time Characterization of Electrospun PVP Nanofibers as Sensitive Layer of a Surface Acoustic Wave Device for Gas Detection

    Directory of Open Access Journals (Sweden)

    D. Matatagui

    2014-01-01

    Full Text Available The goal of this work has been to study the polyvinylpyrrolidone (PVP fibers deposited by means of the electrospinning technique for using as sensitive layer in surface acoustic wave (SAW sensors to detect volatile organic compounds (VOCs. The electrospinning process of the fibers has been monitored and RF characterized in real time, and it has been shown that the diameters of the fibers depend mainly on two variables: the applied voltage and the distance between the needle and the collector, since all the electrospun fibers have been characterized by a scanning electron microscopy (SEM. Real-time measurement during the fiber coating process has shown that the depth of penetration of mechanical perturbation in the fiber layer has a limit. It has been demonstrated that once this saturation has been reached, the increase of the thickness of the fibers coating does not improve the sensitivity of the sensor. Finally, the parameters used to deposit the electrospun fibers of smaller diameters have been used to deposit fibers on a SAW device to obtain a sensor to measure different concentrations of toluene at room temperature. The present sensor exhibited excellent sensitivity, good linearity and repeatability, and high and fast response to toluene at room temperature.

  15. Modelling of plasma-antenna coupling and non-linear radio frequency wave-plasma-wall interactions in the magnetized plasma device under ion cyclotron range of frequencies

    International Nuclear Information System (INIS)

    Lu, LingFeng

    2016-01-01

    Ion Cyclotron Resonant Heating (ICRH) by waves in 30-80 MHz range is currently used in magnetic fusion plasmas. Excited by phased arrays of current straps at the plasma periphery, these waves exist under two polarizations. The Fast Wave tunnels through the tenuous plasma edge and propagates to its center where it is absorbed. The parasitically emitted Slow Wave only exists close to the launchers. How much power can be coupled to the center with 1 A current on the straps? How do the emitted radiofrequency (RF) near and far fields interact parasitically with the edge plasma via RF sheath rectification at plasma-wall interfaces? To address these two issues simultaneously, in realistic geometry over the size of ICRH antennas, this thesis upgraded and tested the Self-consistent Sheaths and Waves for ICH (SSWICH) code. SSWICH couples self-consistently RF wave propagation and Direct Current (DC) plasma biasing via non-linear RF and DC sheath boundary conditions (SBCs) at plasma/wall interfaces. Its upgrade is full wave and was implemented in two dimensions (toroidal/radial). New SBCs coupling the two polarizations were derived and implemented along shaped walls tilted with respect to the confinement magnetic field. Using this new tool in the absence of SBCs, we studied the impact of a density decaying continuously inside the antenna box and across the Lower Hybrid (LH) resonance. Up to the memory limits of our workstation, the RF fields below the LH resonance changed with the grid size. However the coupled power spectrum hardly evolved and was only weakly affected by the density inside the box. In presence of SBCs, SSWICH-FW simulations have identified the role of the fast wave on RF sheath excitation and reproduced some key experimental observations. SSWICH-FW was finally adapted to conduct the first electromagnetic and RF-sheath 2D simulations of the cylindrical magnetized plasma device ALINE. (author) [fr

  16. A comparative analysis of the environmental impacts of a Pelamis Wave Energy device with existing off shore developments and installations.

    OpenAIRE

    Quinn, Eoghan

    2011-01-01

    Scotland is currently at the forefront of development and expansion of wave energy, especially with recent renewable energy targets. Research and development has increased greatly off the Scottish coastline. Various adjectives can be used to describe wave energy’s creative potential in helping to achieve Scotland’s energy goals. Put simply however the production of wave energy appears to have all the ingredients for success; it is benign, the visual impacts minimal and its energy is reliable,...

  17. Effect of inflow discharges on the development of matric suction and volumetric water content for dike during overtopping tests

    Science.gov (United States)

    Hassan, Marwan A.; Ismail, Mohd A. M.

    2017-10-01

    The point of this review is to depict the impact of various inflow discharge rate releases on the instruments of matric suction and volumetric water content during an experimental test of spatial overtopping failure at school of civil engineering in universiti Sains of Malaysia. A dry sand dike was conducted inside small flume channel with twelve sensors of tensiometer and Time-Domain Reflectometer (TDR). Instruments are installed in the soil at different locations in downstream and upstream slopes of the dike for measuring the response of matric suction and volumetric water content, respectively. Two values of inflow discharge rates of 30 and 40 L/min are utilized as a part of these experiments to simulate the effectiveness of water reservoirs in erosion mechanism. The outcomes demonstrate that the matric suction and volumetric water content are decreased and increased, respectively for both inflow discharges. The higher inflow discharges accelerate the saturation of dike soil and the erosion process faster than that for the lower inflow discharges.

  18. 38-GHz millimeter wave beam steered fiber wireless systems for 5G indoor coverage: architectures, devices, and links

    NARCIS (Netherlands)

    Cao, Z.; Zhao, X.; Soares, F.M.; Tessema, N.M.; Koonen, A.M.J.

    2017-01-01

    Millimeter wave (mm-wave) beam steering is a key technique for the next generation (5G) wireless communication. The 28 and 38-GHz bands are widely considered as the candidates for 5G. In the context of indoor coverage, fiber-wireless systems with multiple simplified remote antenna sites are

  19. Multiple-frequency acoustic wave devices for chemical sensing and materials characterization in both gas and liquid phase

    Science.gov (United States)

    Martin, S.J.; Ricco, A.J.

    1993-08-10

    A chemical or intrinsic physical property sensor is described comprising: (a) a substrate; (b) an interaction region of said substrate where the presence of a chemical or physical stimulus causes a detectable change in the velocity and/or an attenuation of an acoustic wave traversing said region; and (c) a plurality of paired input and output interdigitated electrodes patterned on the surface of said substrate where each of said paired electrodes has a distinct periodicity, where each of said paired electrodes is comprised of an input and an output electrode; (d) an input signal generation means for transmitting an input signal having a distinct frequency to a specified input interdigitated electrode of said plurality so that each input electrode receives a unique input signal, whereby said electrode responds to said input signal by generating an acoustic wave of a specified frequency, thus, said plurality responds by generating a plurality of acoustic waves of different frequencies; (e) an output signal receiving means for determining an acoustic wave velocity and an amplitude of said acoustic waves at several frequencies after said waves transverses said interaction region and comparing these values to an input acoustic wave velocity and an input acoustic wave amplitude to produce values for perturbations in acoustic wave velocities and for acoustic wave attenuation as a function of frequency, where said output receiving means is individually coupled to each of said output interdigitated electrode; (f) a computer means for analyzing a data stream comprising information from said output receiving means and from said input signal generation means to differentiate a specified response due to a perturbation from a subsequent specified response due to a subsequent perturbation to determine the chemical or intrinsic physical properties desired.

  20. Validation of a Piezoelectric Sensor Array-Based Device for Measurement of Carotid-Femoral Pulse Wave Velocity: The Philips Prototype.

    Science.gov (United States)

    Xu, Shao-Kun; Hong, Xiang-Fei; Cheng, Yi-Bang; Liu, Chang-Yuan; Li, Yan; Yin, Bin; Wang, Ji-Guang

    2018-03-01

    Multiple piezoelectric pressure mechanotransducers topologized into an array might improve efficiency and accuracy in collecting arterial pressure waveforms for measurement of pulse wave velocity (PWV). In the present study, we validated a piezoelectric sensor array-based prototype (Philips) against the validated and clinically widely used Complior device (Alam Medical). We recruited 33 subjects with a wide distribution of PWV. For the validation, PWV was measured sequentially with the Complior device (four times) and the Philips prototype (three times). With the 99 paired PWV values, we investigated the agreement between the Philips prototype and the Complior device using Pearson correlation analysis and Bland-Altman plot. We also performed analysis on the determinants and reproducibility of PWV measured with both devices. The correlation coefficient for PWV measured with the two devices was 0.92 ( p prototype slightly overestimated PWV by 0.24 (± 2 standard deviations, ± 1.91) m/s, especially when PWV was high. The correlation coefficient between the difference and the average of the Philips and Complior measurements was 0.21 ( p = 0.035). Nonetheless, they had similar determinants. Age, mean arterial pressure, and sex altogether explained 81.6 and 83.9% of the variance of PWV values measured with the Philips prototype and Complior device, respectively. When the two extremes of the three PWV values measured with the Philips prototype and the Complior device were investigated, the coefficients of variation were 8.26 and 3.26%, respectively. Compared with the Complior device, the Philips prototype had similar accuracy, determinants, and reproducibility in measuring PWV.

  1. Contribution to coherent atom optics - Design of multiple wave devices; Contribution a l'optique des ondes atomiques coherentes - Conception de dispositifs multi-ondes

    Energy Technology Data Exchange (ETDEWEB)

    Impens, F

    2008-03-15

    The theoretical work presented in this manuscript addresses two complementary issues in coherent atom optics. The first part addresses the perspectives offered by coherent atomic sources through the design of two experiment involving the levitation of a cold atomic sample in a periodic series of light pulses, and for which coherent atomic clouds are particularly well-suited. These systems appear as multiple wave atom interferometers. A striking feature of these experiments is that a unique system performs both the sample trapping and interrogation. To obtain a transverse confinement, a novel atomic lens is proposed, relying on the interaction between an atomic wave with a spherical light wave. The sensitivity of the sample trapping towards the gravitational acceleration and towards the pulse frequencies is exploited to perform the desired measurement. These devices constitute atomic wave resonators in momentum space, which is a novel concept in atom optics. A second part develops new theoretical tools - most of which inspired from optics - well-suited to describe the propagation of coherent atomic sources. A phase-space approach of the propagation, relying on the evolution of moments, is developed and applied to study the low-energy dynamics of Bose-Einstein condensates. The ABCD method of propagation for atomic waves is extended beyond the linear regime to account perturbatively for mean-field atomic interactions in the atom-optical aberration-less approximation. A treatment of the atom laser extraction enabling one to describe aberrations in the atomic beam, developed in collaboration with the Atom Optics group at the Institute of Optics, is exposed. Last, a quality factor suitable for the characterization of diluted matter waves in a general propagation regime has been proposed. (author)

  2. Temperature stable LiNbO3 surface acoustic wave device with diode sputtered amorphous TeO2 over-layer

    International Nuclear Information System (INIS)

    Dewan, Namrata; Tomar, Monika; Gupta, Vinay; Sreenivas, K.

    2005-01-01

    Amorphous TeO 2 thin film, sputtered in the O 2 +Ar(25%+75%) gas environment using a metallic tellurium target, has been identified as an attractive negative temperature coefficient of delay (TCD) material that can yield a temperature stable device when combined with a surface acoustic wave (SAW) device based on positive TCD material such as LiNbO 3 . The influence of amorphous TeO 2 over-layer on the SAW propagation characteristics (velocity and temperature coefficient of delay) of the SAW filters (36 and 70 MHz) based on 128 deg. rotated Y-cut X-propagating lithium niobate (128 deg. Y-X LiNbO 3 ) single crystal has been studied. It is found that 0.042 λ thick TeO 2 over-layer on a prefabricated SAW device operating at 36 MHz centre frequency, reduces the TCD of the device from 76 ppm deg. C -1 to almost zero (∼1.4 ppm deg. C -1 ) without deteriorating its efficiency and could be considered as a suitable alternative for temperature stable devices in comparison to conventional SiO 2 over-layer

  3. An assessment of long-term overtopping risk and optimal termination time of dam under climate change.

    Science.gov (United States)

    Lee, Bau-Shian; You, Gene Jiing-Yun

    2013-05-30

    Reservoir management faces a wide range of new challenges resulting from the impact of climate change. One set of challenges arises from the non-stationary nature of hydrological conditions. Another crucial issue is watershed sedimentation, which can significantly influence the sustainability and safety of reservoirs. To address these concerns, this study developed a framework for the management of reservoir risk. An analytical conceptual model coupling physical governing relationships and economic tools was proposed, which was then applied to the Shihmen Reservoir in Taiwan. We adopted a statistical representation of future hydrologic conditions with the assumption of time-variant moments and focused on evaluating the impact of an increase in the frequency of extreme hydrological events caused by climate change and used a stochastic approach to quantify the risk factors. Our results confirm that this approach can be used to identify reservoir-related risks and generate appropriate options for strategy and policy. We determined that the major source of risk is the hydrological conditions, especially the extreme events. More severe intra-annual climatic change is much more dominant in the risk compared to inter-year trends. The influence of reservoir characteristics on risk is associated mainly with the availability of flood control capacity, but limited due to the limitation of its volume and potential to regulate the flow. Engineering may provide an option for mitigating the risk, but integrated, watershed-level approaches, such as providing systematic detention or land use management, are better suited to reducing the storm peak from a long-term perspective. With a critical increase in the risk of overtopping, a high probability of dam failure and corresponding losses may precipitate the need to retire or remove the facility. However, because the benefits and costs are both huge, the decision may be biased by a conservative attitude. The outcome of small

  4. Wave Dragon

    DEFF Research Database (Denmark)

    Tedd, James; Kofoed, Jens Peter; Friis-Madsen, Erik

    2008-01-01

    Since March 2003 a prototype of Wave Dragon has been tested in an inland sea in Denmark. This has been a great success with all subsystems tested and improved through working in an offshore environment. The project has proved the Wave Dragon device and has enabled the next stage, a production sized...

  5. High-frequency Lamb wave device composed of MEMS structure using LiNbO3 thin film and air gap.

    Science.gov (United States)

    Kadota, Michio; Ogami, Takashi; Yamamoto, Kansho; Tochishita, Hikari; Negoro, Yasuhiro

    2010-11-01

    High-frequency devices operating at 3 GHz or higher are required, for instance, for future 4th generation mobile phone systems in Japan. Using a substrate with a high acoustic velocity is one method to realize a high-frequency acoustic or elastic device. A Lamb wave has a high velocity when the substrate thickness is thin. To realize a high-frequency device operating at 3 GHz or higher using a Lamb wave, a very thin (less than 0.5 μm thick) single-crystal plate must be used. It is difficult to fabricate such a very thin single crystal plate. The authors have attempted to use a c-axis orientated epitaxial LiNbO(3) thin film deposited by a chemical vapor deposition system (CVD) instead of using a thin LiNbO(3) single crystal plate. Lamb wave resonators composed of a interdigital transducer (IDT)/the LiNbO(3) film/air gap/base substrate structure like micro-electromechanical system (MEMS) transducers were fabricated. These resonators have shown a high frequency of 4.5 and 6.3 GHz, which correspond to very high acoustic velocities of 14,000 and 12,500 m/s, respectively, have excellent characteristics such as a ratio of resonant and antiresonant impedance of 52 and 38 dB and a wide band of 7.2% and 3.7%, respectively, and do not have spurious responses caused by the 0th modes of shear horizontal (SH(0)) and symmetric (S(0)) modes.

  6. Development of the 'SEA-Clam' wave energy device for small scale use. Interim report 1st August 1983 - 30th April 1984

    Energy Technology Data Exchange (ETDEWEB)

    1984-04-01

    An Interim Report on the development of the Sea-Clam wave energy device for small scale use is presented. Experimental tests to measure the productivity of the Clam system, using 1/14th linear scale models of a 80 m long x 7 to 9 m deep x 5 m wide device intended for small community use are outlined. A feature of these experiments has been the development of a rotating damper which enables damping rate to be readily varied during a series of successive tests, a major advance in power measurements of air systems at this scale. Development of corded bags, progress made during the period with mathematical modelling of the turbine-generator power take-off system, and use of paralleled induction generators run at near-synchronous speed in conjuction with either a 3-phase base supply or an on-board alternator to provide magnetization current are discussed.

  7. Development of the 'SEA-Clam' wave energy device for small scale use. Interim report 1st August 1983 - 30th April 1984

    Energy Technology Data Exchange (ETDEWEB)

    1984-04-01

    An Interim Report on the development of the Sea-Clam wave energy device for small scale use is presented. Experimental tests to measure the productivity of the Clam system, using 1/14th linear scale models of a 80 m long x 7 to 9 m deep x 5 m wide device intended for small community use are outlined. A feature of these experiments has been the development of a rotating damper which enables damping rate to be readily varied during a series of successive tests, a major advance in power measurements of air systems at this scale. Development of corded bags, progress made during the period with mathematical modelling of the turbine-generator power take-off system, and use of paralleled induction generators run at near-synchronous speed in conjuction with either a 3-phase base supply or an on-board alternator to provide magnetization current are discussed.

  8. A real time 155 GHz millimeter wave interferometer module for electron density measurement in large plasma devices

    International Nuclear Information System (INIS)

    Huettemann, P.W.; Waidmann, G.

    1982-09-01

    A homodyne, real time 155 GHz interferometer channel is described which is one module of a multichannel system for use on TEXTOR tokamak. A standing sine wave is generated in a phase bridge by transmitting a frequency modulated millimeter wave down two unequal interferometer branches. The presence of plasma produces a phase slip of the sine wave with respect to a reference signal. The phase shift is linear proportional to plasma density for expected TEXTOR plasmas. Long plasma paths give multiradian phase shifts which are recorded by a digital fringe counting system. The accuracy of phase measurement is ΔPHI = 2π/16. Phase changes of 7π/8 are accepted per modulation period. The microwave in the measurement branch of the interferometer is transmitted using a quasioptical technique. Components and technical details are described. The interferometer was tested in a simulation set-up and in two different plasma experiments. Experimental results are presented. (orig.)

  9. The effect of post-annealing on surface acoustic wave devices based on ZnO thin films prepared by magnetron sputtering

    International Nuclear Information System (INIS)

    Phan, Duy-Thach; Chung, Gwiy-Sang

    2011-01-01

    Zinc oxide (ZnO) thin films were deposited on unheated silicon substrates via radio frequency (RF) magnetron sputtering, and the post-deposition annealing of the ZnO thin films was performed at 400 deg. C, 600 deg. C, 800 deg. C, and 1000 deg. C. The characteristics of the thin films were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The films were then used to fabricate surface acoustic wave (SAW) resonators. The effects of post-annealing on the SAW devices are discussed in this work. Resulting in the 600 deg. C is determined as optimal annealing temperature for SAW devices. At 400 deg. C, the microvoids exit between the grains yield large root mean square (RMS) surface roughness and higher insertion losses in SAW devices. The highest RMS surface roughness, crack and residual stress cause a reduction of surface velocity (about 40 m/s) and increase dramatically insertion loss at 1000 deg. C. The SAW devices response becomes very weak at this temperature, the electromechanical coupling coefficient (k 2 ) of ZnO film decrease from 3.8% at 600 deg. C to 1.49% at 1000 deg. C.

  10. An Assessment of Hazards Caused by Electromagnetic Interaction on Humans Present near Short-Wave Physiotherapeutic Devices of Various Types Including Hazards for Users of Electronic Active Implantable Medical Devices (AIMD

    Directory of Open Access Journals (Sweden)

    Jolanta Karpowicz

    2013-01-01

    Full Text Available Leakage of electromagnetic fields (EMF from short-wave radiofrequency physiotherapeutic diathermies (SWDs may cause health and safety hazards affecting unintentionally exposed workers (W or general public (GP members (assisting patient exposed during treatment or presenting there for other reasons. Increasing use of electronic active implantable medical devices (AIMDs, by patients, attendants, and workers, needs attention because dysfunctions of these devices may be caused by electromagnetic interactions. EMF emitted by 12 SWDs (with capacitive or inductive applicators were assessed following international guidelines on protection against EMF exposure (International Commission on Nonionizing Radiation Protection for GP and W, new European directive 2013/35/EU for W, European Recommendation for GP, and European Standard EN 50527-1 for AIMD users. Direct EMF hazards for humans near inductive applicators were identified at a distance not exceeding 45 cm for W or 62 cm for GP, but for AIMD users up to 90 cm (twice longer than that for W and 50% longer than that for GP because EMF is pulsed modulated. Near capacitive applicators emitting continuous wave, the corresponding distances were: 120 cm for W or 150 cm for both—GP or AIMD users. This assessment does not cover patients who undergo SWD treatment (but it is usually recommended for AIMD users to be careful with EMF treatment.

  11. Impact of layer and substrate properties on the surface acoustic wave velocity in scandium doped aluminum nitride based SAW devices on sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Gillinger, M., E-mail: manuel.gillinger@tuwien.ac.at; Knobloch, T.; Schneider, M.; Schmid, U. [Institute of Sensor and Actuator Systems, TU Wien, 1040 Vienna (Austria); Shaposhnikov, K.; Kaltenbacher, M. [Institute of Mechanics and Mechatronics, TU Wien, 1040 Vienna (Austria)

    2016-06-06

    This paper investigates the performance of surface acoustic wave (SAW) devices consisting of reactively sputter deposited scandium doped aluminum nitride (Sc{sub x}Al{sub 1-x}N) thin films as piezoelectric layers on sapphire substrates for wireless sensor or for RF-MEMS applications. To investigate the influence of piezoelectric film thickness on the device properties, samples with thickness ranging from 500 nm up to 3000 nm are fabricated. S{sub 21} measurements and simulations demonstrate that the phase velocity is predominantly influenced by the mass density of the electrode material rather than by the thickness of the piezoelectric film. Additionally, the wave propagation direction is varied by rotating the interdigital transducer structures with respect to the crystal orientation of the substrate. The phase velocity is about 2.5% higher for a-direction compared to m-direction of the sapphire substrate, which is in excellent agreement with the difference in the anisotropic Young's modulus of the substrate corresponding to these directions.

  12. Longitudinal evaluation of P-wave dispersion and P-wave maximum in children after transcatheter device closure of secundum atrial septal defect.

    Science.gov (United States)

    Grignani, Robert Teodoro; Tolentino, Kim Martin; Rajgor, Dimple Dayaram; Quek, Swee Chye

    2015-06-01

    Transcatheter device closure of the secundum atrial septal defect (ASD) in children prevents atrial arrhythmias in older age. However, the benefits of favourable atrial electrocardiographic markers in these children remain elusive. We aimed to review the electrocardiographic markers of atrial activity in a longitudinal fashion. We retrospectively reviewed longitudinal data of all children who underwent transcatheter device closure at the National University Hospital between 2004 and 2013. The inclusion criteria included the presence of a secundum-type ASD with left to right shunt and evidence of increased right ventricular volume load (Q p/Q s ratio >1.5 and/or right ventricular dilatation). A total of 25 patients with a mean follow-up of 44.7 ± 33.47 (7.3-117.4) months were included. P maximum and P dispersion decreased at 2 months, P amplitude at 1 week and remained so until last follow-up. A positive trend was seen with a correlation coefficient of +0.12 for P maximum, +0.08 for P dispersion and 0.34 for P amplitude. There was a higher baseline P amplitude and P dispersion in patients who were older than 10 years and a non-significant trend to support an increase in both P maximum (71.0 ± 8.8 vs. 73.2 ± 12.7), P dispersion (17.0 ± 6.5 vs. 22.0 ± 11.3) and P amplitude (0.88 ± 0.25 vs. 1.02 ± 0.23) in patients with an ASD more than 15 mm compared with an ASD <15 mm. There is reduction in both P maximum and P dispersion as early as 2 months, which persisted on follow-up. Earlier closure may result in more favourable electrocardiographic results.

  13. Large-signal modeling of multi-finger InP DHBT devices at millimeter-wave frequencies

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Midili, Virginio; Squartecchia, Michele

    2017-01-01

    A large-signal modeling approach has been developed for multi-finger devices fabricated in an Indium Phosphide (InP) Double Heterojunction Bipolar Transistor (DHBT) process. The approach utilizes unit-finger device models embedded in a multi-port parasitic network. The unit-finger model is based...... on an improved UCSD HBT model formulation avoiding an erroneous RciCbci transit-time contribution from the intrinsic collector region as found in other III-V based HBT models. The mutual heating between fingers is modeled by a thermal coupling network with parameters extracted from electro-thermal simulations...

  14. Wave energy

    Energy Technology Data Exchange (ETDEWEB)

    Whittaker, T.J.T. (Queen' s Univ., Belfast, Northern Ireland (UK)); White, P.R.S. (Lanchester Polytechnic, Coventry (UK)); Baker, A.C.J. (Binnie and Partners, London (UK))

    1988-10-01

    An informal discussion on various wave energy converters is reported. These included a prototype oscillating water column (OWC) device being built on the Isle of Islay in Scotland; the SEA Clam; a tapering channel device (Tapchan) raising incoming waves into a lagoon on a Norwegian island and an OWC device on the same island. The Norwegian devices are delivering electricity at about 5.5p/KWh and 4p/KWh respectively with possibilities for reduction to 2.5-3p/KWh and 3p/KWh under favourable circumstances. The discussion ranged over comparisons with progress in wind power, engineering aspects, differences between inshore and offshore devices, tidal range and energy storage. (UK).

  15. Power transmission study for a wave energy scheme based on Lancaster Flexible Bag devices. Supervisory and telecontrol system

    Energy Technology Data Exchange (ETDEWEB)

    1981-11-01

    Various options are considered for power data transmission associated with the power collection and transmission system of a postulated wave energy conversion scheme off the Outer Hebrides. For data transmission between the off-shore and on-shore power collector stations a Power Line Carrier (PLC) system is judged to be most suitable. In the case of data transmission between power collector stations and the main control centre, a microwave/radio link is proposed as the amount of data does not lend itself to a PLC system. Cost estimates, in the main for equipment supply only, are given.

  16. Functionalization of embedded thiol-ene waveguides for evanescent wave induced fluorescence detection in a microfluidic device

    DEFF Research Database (Denmark)

    Feidenhans'l, Nikolaj Agentoft; Jensen, Thomas Glasdam; Lafleur, Josiane P.

    2013-01-01

    We demonstrate the use of functional surface groups inherently present on off-stoichiometric thiol−ene polymers, for site-specific immobilization of biomolecules and detection by evanescent wave-induced fluorescence. An optofluidic chip featuring an embedded thiol−ene waveguide was selectively...... functionalized with biotin using photografting. The biotin was used for immobilization of fluorescently labelled streptavidin, and experiments revealed a linear correlation between streptavidin concentration and fluorescent intensity. To further demonstrate the attractiveness of using thiol−ene for optofluidic...

  17. Inducing Strong Non-Linearities in a Phonon Trapping Quartz Bulk Acoustic Wave Resonator Coupled to a Superconducting Quantum Interference Device

    Directory of Open Access Journals (Sweden)

    Maxim Goryachev

    2018-04-01

    Full Text Available A quartz Bulk Acoustic Wave resonator is designed to coherently trap phonons in such a way that they are well confined and immune to suspension losses so they exhibit extremely high acoustic Q-factors at low temperature, with Q × f products of order 10 18 Hz. In this work we couple such a resonator to a Superconducting Quantum Interference Device (SQUID amplifier and investigate effects in the strong signal regime. Both parallel and series connection topologies of the system are investigated. The study reveals significant non-Duffing response that is associated with the nonlinear characteristics of Josephson junctions. The nonlinearity provides quasi-periodic structure of the spectrum in both incident power and frequency. The result gives an insight into the open loop behaviour of a future Cryogenic Quartz Oscillator in the strong signal regime.

  18. An integrated wave modelling framework for extreme and rare events for climate change in coastal areas – the case of Rethymno, Crete

    Directory of Open Access Journals (Sweden)

    Vasiliki K. Tsoukala

    2016-04-01

    Full Text Available Coastal floods are regarded as among the most dangerous and harmful of all natural disasters affecting urban areas adjacent to the shorelines. Rapid urbanization combined with climate change and poor governance often results in significant increase of flood risk, especially for coastal communities. Wave overtopping and wave run-up are the key mechanisms for monitoring the results of coastal flooding and as such, significant efforts are currently focusing on their predicting. In this paper, an integrated methodology is proposed, accounting for wave overtopping and wave run-up under extreme wave scenarios caused by storm surges. By taking advantage of past and future climatic projections of wind data, a downscaling approach is proposed, utilizing a number of appropriate numerical models than can simulate the wave propagation from offshore up to the swash zone. The coastal zone of Rethymno in Greece is selected as a case study area and simulations of wave characteristics with the model SWAN for the period 1960–2100 in the offshore region are presented. These data are given as boundary conditions to further numerical models (MIKE21 PMS and HD in order to investigate the spatial evolution of the wave and the hydrodynamic field in intermediate and shallow waters. Finally, the calculated wave height serves as input to empirical formulas and time dependent wave propagation models (MIKE21 BW to estimate the wave run-up and wave overtopping (EurOtop. It is suggested that the proposed procedure is generic enough to be applicable to any similar region.

  19. Complex rehabilitation and the clinical condition of working rheumatoid arthritis patients: does cryotherapy always overtop traditional rehabilitation?

    Science.gov (United States)

    Księżopolska-Orłowska, Krystyna; Pacholec, Anna; Jędryka-Góral, Anna; Bugajska, Joanna; Sadura-Sieklucka, Teresa; Kowalik, Katarzyna; Pawłowska-Cyprysiak, Karolina; Łastowiecka-Moras, Elżbieta

    2016-01-01

    traditional approach showed decreased disease activity following the initial 3-week period; however, this improvement did not sustain to the end of follow-up, 3 months later. Complex rehabilitation in RA has a positive effect on patients' clinical condition. The rehabilitation programme that includes cryotherapy overtops traditional rehabilitation, particularly as regards improvement in locomotor function, disease activity and sustaining willingness to continue working and exerts long-lasting effect. Rehabilitation using cryotherapy is more effective in improving locomotor function, decreasing disease activity and sustaining willingness to continue working compared to traditional rehabilitation. Rehabilitation using cryotherapy significantly reduces the intensity of pain experienced by patients with RA, and this positive effect is maintained at 3 months post-rehabilitation. Complex rehabilitation, particularly treatment using cryotherapy, improves patients' subjective assessment of their overall well-being and perception of their disease. Complex rehabilitation in rheumatoid arthritis has a positive effect on patients' clinical condition.

  20. Effects of Compressibility on the Performance of a Wave-Energy Conversion Device with an Impulse Turbine Using a Numerical Simulation Technique

    Directory of Open Access Journals (Sweden)

    A. Thakker

    2003-01-01

    Full Text Available This article presents work carried out to predict the behavior of a 0.6 m impulse turbine with fixed guide vanes as compared with that of a 0.6 hub-to-tip ratio turbine under real sea conditions. In order to predict the true performance of the actual oscillating water column (OWC, the numerical technique was fine-tuned by incorporating the compressibility effect. Water surface elevation versus time history was used as the input data for this purpose. The effect of compressibility inside the air chamber and the turbine's performance under unsteady and irregular flow conditions were analyzed numerically. Considering the quasi-steady assumptions, the unidirectional steady-flow experimental data was used to simulate the turbines characteristics under irregular unsteady flow conditions. The results showed that the performance of this type of turbine is quite stable and that the efficiency of the air chamber and the mean conversion efficiency are reduced by around 8% and 5%, respectively, as a result of the compressibility inside the air chamber. The mean efficiencies of the OWC device and the impulse turbine were predicted for 1 month, based on the Irish wave climate, and it was found that the total time period of wave data used is one of the important factors in the simulation technique.

  1. Correlación entre ondas de ensayo para dispositivos supresores de sobretensiones Correlation factor between standard surge waves for testing transient overvoltage suppressor devices

    Directory of Open Access Journals (Sweden)

    Julio Guillermo Zola

    2008-06-01

    Full Text Available Existe un variado número de ondas impulsivas estándar que se utilizan para ensayar el funcionamiento de los dispositivos supresores de sobretensiones transitorias. En particular, resultan de importancia los ensayos que comprueban la corriente máxima de impulso de descarga. Se analiza en este trabajo la relación existente entre estas distintas formas de ondas impulsivas, de forma tal de poder obtener una correlación entre ellas para aplicar una u otra con similares resultados. Las conclusiones que se alcanzan a partir de un desarrollo teórico simplificado son corroboradas mediante medición en laboratorio y simulación.A wide number of standard surge waves current for testing the behavior of transient overvoltage suppressor devices are currently being used. The value of pick surge current is one of the most important tests. The ratio between the surge waves to obtain a correlation factor between them, so they can be applied to get equivalent results is analyzed in this paper. The theoretical conclusions are verified by simulation and laboratory measurements.

  2. A novel device for measuring arterial stiffness using finger-toe pulse wave velocity: Validation study of the pOpmètre®.

    Science.gov (United States)

    Alivon, Maureen; Vo-Duc Phuong, Thao; Vignon, Virginie; Bozec, Erwan; Khettab, Hakim; Hanon, Olivier; Briet, Marie; Halimi, Jean-Michel; Hallab, Magid; Plichart, Matthieu; Mohammedi, Kamel; Marre, Michel; Boutouyrie, Pierre; Laurent, Stéphane

    2015-04-01

    The finger-toe pathway could be a good alternative for assessing arterial stiffness conveniently. To evaluate the accuracy of the pOpmètre®--a new device that measures finger-toe pulse wave velocity (ft-PWV). The pOpmètre has two photodiode sensors, positioned on the finger and the toe. Pulse waves are recorded continuously for 20 seconds, and the difference in pulse wave transit time between toe and finger (ft-TT) is calculated. The travelled distance is estimated using subject height. Study 1 compared ft-PWV with carotid-femoral PWV (cf-PWV) obtained by the reference method (SphygmoCor®) in 86 subjects (mean age 53±20 years), including 69 patients with various pathologies and 17 healthy normotensives. Study 2 compared changes in ft-PWV and cf-PWV during a cold pressor test in 10 healthy subjects. Study 3 assessed repeatability in 45 patients. ft-PWV correlated significantly with cf-PWV (R2=0.43; P<0.0001). A better correlation was found in terms of transit time (R2=0.61; P<0.0001). The discrepancy between transit times was related to age. The cold pressor test induced parallel changes in cf-PWV and ft-PWV, with increased aortic stiffness that was reversible during recovery. Intra-session repeatability was very good, with a coefficient of variation of 4.52%. The pOpmètre® allows measurement of arterial stiffness in routine clinical practice. The greatest advantages of ft-PWV are simplicity, rapidity, feasibility, acceptability by patients and correct agreement with the reference technique. Further studies are needed to adjust for bias and to validate the pOpmètre in larger populations. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  3. Seismic wave generator

    International Nuclear Information System (INIS)

    Devaure, Bernard.

    1982-01-01

    This invention concerns a device for simulating earth tremors. This device includes a seismic wave generator formed of a cylinder, one end of which is closed by one of the walls of a cell containing a soil, the other end being closed by a wall on which are fixed pyrotechnic devices generating shock waves inside the cylinder. These waves are transmitted from the cylinder to the cell through openings made in the cell wall. This device also includes a mechanical device acting as low-pass filter, located inside the cylinder and close to the cell wall [fr

  4. A DAQ-Device-Based Continuous Wave Near-Infrared Spectroscopy System for Measuring Human Functional Brain Activity

    Directory of Open Access Journals (Sweden)

    Gang Xu

    2014-01-01

    Full Text Available In the last two decades, functional near-infrared spectroscopy (fNIRS is getting more and more popular as a neuroimaging technique. The fNIRS instrument can be used to measure local hemodynamic response, which indirectly reflects the functional neural activities in human brain. In this study, an easily implemented way to establish DAQ-device-based fNIRS system was proposed. Basic instrumentation components (light sources driving, signal conditioning, sensors, and optical fiber of the fNIRS system were described. The digital in-phase and quadrature demodulation method was applied in LabVIEW software to distinguish light sources from different emitters. The effectiveness of the custom-made system was verified by simultaneous measurement with a commercial instrument ETG-4000 during Valsalva maneuver experiment. The light intensity data acquired from two systems were highly correlated for lower wavelength (Pearson’s correlation coefficient r = 0.92, P < 0.01 and higher wavelength (r = 0.84, P < 0.01. Further, another mental arithmetic experiment was implemented to detect neural activation in the prefrontal cortex. For 9 participants, significant cerebral activation was detected in 6 subjects (P < 0.05 for oxyhemoglobin and in 8 subjects (P < 0.01 for deoxyhemoglobin.

  5. A laser gyro with a four-mirror square resonator: formulas for simulating the dynamics of the synchronisation zone parameters of the frequencies of counterpropagating waves during the device operation in the self-heating regime

    International Nuclear Information System (INIS)

    Bondarenko, E A

    2014-01-01

    For a laser gyro with a four-mirror square resonator we have developed a mathematical model, which allows one to simulate the temporal behaviour of the synchronisation zone parameters of the frequencies of counterpropagating waves in a situation when the device operates in the self-heating regime and is switched-on at different initial temperatures. (laser gyroscopes)

  6. Wave Dragon Wave Energy Converters Used as Coastal Protection

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Thomas Lykke; Kofoed, Jens Peter

    2011-01-01

    This paper deals with wave energy converters used to reduce the wave height along shorelines. For this study the Wave Dragon wave energy converter is chosen. The wave height reduction from a single device has been evaluated from physical model tests in scale 1:51.8 of the 260 x 150 m, 24 kW/m model...... Spain, to evaluate the potential for reducing wave heights close the shore by means of Wave Dragons....

  7. A Case Study of Short-term Wave Forecasting Based on FIR Filter: Optimization of the Power Production for the Wavestar Device

    DEFF Research Database (Denmark)

    Ferri, Francesco; Sichani, Mahdi Teimouri; Frigaard, Peter

    2012-01-01

    Short-term wave forecasting plays a crucial role for the control of a wave energy converter (WEC), in order to increase the energy harvest from the waves, as well as to increase its life time. In the paper it is shown how the surface elevation of the waves and the force acting on the WEC can be p...

  8. [Pulse wave velocity of the leg minus that of the arm measured with a custom device correlates to the coronary calcium quantification].

    Science.gov (United States)

    Rico Martín, S; de Nicolás Jiménez, J M; Moyano Calvente, S L; Mogollón Jiménez, M V; Vega Fernández, J; Calderón García, J F; Bacaicoa Lopez de Sabando, M A; Tardio, M; Sánchez Muñoz-Torrero, J F

    2016-05-01

    The pulse wave velocity (PWV) in the great arteries is an indicator of vascular risk. Our objective was to identify the PWV index between the arms and legs that best correlates with the coronary calcium quantification (CCQ) and to compare it with other methods. Eight-one patients without vascular disease underwent the following measurements: CCQ; carotid intima-media thickness (IMT); carotid-femoral PWV (cfPWV), using COMPLIOR; and PWV in the arms and legs, with our own device (abiPWV, ankle brachial index PWV). The difference in PWVs between the leg and arm (l-a PWV) measured with abiPWV was the index that best correlated with CCQ (r=0.401, P<.001). The correlation between IMT and CCQ and between CF-PWV and CCQ were r=0.366, P=.001; and r=0.385, P=.001, respectively. For a CCQ score higher than 100 as a marker of significant coronary arteriosclerosis, the areas under the curve for l-a PWV, IMT and cfPWV were 0.721 (P=.002), 0.758 (P<.001) and 0.636 (P=.058), respectively. For patients without vascular disease, the l-a PWV measured with abiPWV appears to be the index that best correlates with the CCQ. This association is comparable to that between IMT and CCQ and between cfPWV and CCQ. The abiPWV is an easy-to-use device that can help improve vascular risk stratification. Copyright © 2016 Elsevier España, S.L.U. y Sociedad Española de Medicina Interna (SEMI). All rights reserved.

  9. Love Acoustic Wave-Based Devices and Molecularly-Imprinted Polymers as Versatile Sensors for Electronic Nose or Tongue for Cancer Monitoring

    Directory of Open Access Journals (Sweden)

    Corinne Dejous

    2016-06-01

    Full Text Available Cancer is a leading cause of death worldwide and actual analytical techniques are restrictive in detecting it. Thus, there is still a challenge, as well as a need, for the development of quantitative non-invasive tools for the diagnosis of cancers and the follow-up care of patients. We introduce first the overall interest of electronic nose or tongue for such application of microsensors arrays with data processing in complex media, either gas (e.g., Volatile Organic Compounds or VOCs as biomarkers in breath or liquid (e.g., modified nucleosides as urinary biomarkers. Then this is illustrated with a versatile acoustic wave transducer, functionalized with molecularly-imprinted polymers (MIP synthesized for adenosine-5′-monophosphate (AMP as a model for nucleosides. The device including the thin film coating is described, then static measurements with scanning electron microscopy (SEM and electrical characterization after each step of the sensitive MIP process (deposit, removal of AMP template, capture of AMP target demonstrate the thin film functionality. Dynamic measurements with a microfluidic setup and four targets are presented afterwards. They show a sensitivity of 5 Hz·ppm−1 of the non-optimized microsensor for AMP detection, with a specificity of three times compared to PMPA, and almost nil sensitivity to 3′AMP and CMP, in accordance with previously published results on bulk MIP.

  10. Kinematics and dynamics of green water on a fixed platform in a large wave basin in focusing wave and random wave conditions

    Science.gov (United States)

    Chuang, Wei-Liang; Chang, Kuang-An; Mercier, Richard

    2018-06-01

    Green water kinematics and dynamics due to wave impingements on a simplified geometry, fixed platform were experimentally investigated in a large, deep-water wave basin. Both plane focusing waves and random waves were employed in the generation of green water. The focusing wave condition was designed to create two consecutive plunging breaking waves with one impinging on the frontal vertical wall of the fixed platform, referred as wall impingement, and the other directly impinging on the deck surface, referred as deck impingement. The random wave condition was generated using the JONSWAP spectrum with a significant wave height approximately equal to the freeboard. A total of 179 green water events were collected in the random wave condition. By examining the green water events in random waves, three different flow types are categorized: collapse of overtopping wave, fall of bulk water, and breaking wave crest. The aerated flow velocity was measured using bubble image velocimetry, while the void fraction was measured using fiber optic reflectometry. For the plane focusing wave condition, measurements of impact pressure were synchronized with the flow velocity and void fraction measurements. The relationship between the peak pressures and the pressure rise times is examined. For the high-intensity impact in the deck impingement events, the peak pressures are observed to be proportional to the aeration levels. The maximum horizontal velocities in the green water events in random waves are well represented by the lognormal distribution. Ritter's solution is shown to quantitatively describe the green water velocity distributions under both the focusing wave condition and the random wave condition. A prediction equation for green water velocity distribution under random waves is proposed.

  11. Guide device

    International Nuclear Information System (INIS)

    Brammer, C.M. Jr.

    1977-01-01

    Disclosed is a fuel handling guide tube centering device for use in nuclear reactors during fuel assembly handling operations. The device comprises an outer ring secured to the flange of a nuclear reactor pressure vessel, a rotatable table rotatably coupled to the outer ring, and a plurality of openings through the table. Truncated locating cones are positioned in each of the openings in the table, and the locating cones center the guide tube during fuel handling operations. The openings in the table are located such that each fuel assembly in the nuclear core may be aligned with one of the openings by a suitable rotation of the table. The locating cones thereby provide alignment between the fuel handling mechanism located in the guide tube and the individual fuel assemblies of the cone. The need for a device to provide alignment is especially critical for floating nuclear power plants, where wave motion may exist during fuel handling operations. 5 claims, 4 figures

  12. 基于不确定时间区间TBN的洪水漫坝风险分析%Risk Analysis of Flood Overtopping Based on Uncertain Time Interval TBN

    Institute of Scientific and Technical Information of China (English)

    涂传飞; 王剑; 王红卫

    2013-01-01

    In the process of flood overtopping,the uncertainty of events' duration time caused by state uncertainty of natural conditions,dam and emergency measures,and the effect of emergency measures are both key factors that affect the flood overtopping risk.The traditional time interval was transformed into an uncertain time interval and an uncertain time interval Temporal Bayesian Network (TBN) was proposed.After that,a new inferring algorithm of the TBN was discussed.On the basis,flood overtopping risk analysis model,in which emergency measures were considered,was established.Finally,the simulation result shows that the model can accumulate information,judge the importance of each emergency measure,express the state uncertainty and time uncertainty which both exist in the process of flood overtopping and accordingly increase the accuracy of flood overtopping risk analysis.%洪水漫坝过程中,自然条件、坝体及应急处置等状态的不确定性所导致的事件持续时间的不确定性,以及应急处置措施的效果是影响漫坝风险的关键因素.首先将传统时间区间改造为不确定时间区间,提出了一种不确定时间区间时间贝叶斯网络(TBN),并推导了该TBN的推理算法.在此基础上构建了考虑应急处置措施的洪水漫坝风险分析模型.仿真结果表明该模型具有信息时间累积能力,能判断各应急处置措施的重要程度,表达了洪水漫坝过程中同时存在的状态不确定性和时间不确定性,提高了漫坝风险分析的精度.

  13. Stochastic Modeling of Long-Term and Extreme Value Estimation of Wind and Sea Conditions for Probabilistic Reliability Assessments of Wave Energy Devices

    DEFF Research Database (Denmark)

    Ambühl, Simon; Kofoed, Jens Peter; Sørensen, John Dalsgaard

    2014-01-01

    Wave energy power plants are expected to become one of the major future contribution to the sustainable electricity production. Optimal design of wave energy power plants is associated with modeling of physical, statistical, measurement and model uncertainties. This paper presents stochastic models...... for the significant wave height, the mean zero-crossing wave period and the wind speed for long-term and extreme estimations. The long-term estimation focuses on annual statistical distributions, the inter-annual variation of distribution parameters and the statistical uncertainty due to limited amount of data...

  14. Quality assurance of geometric accuracy based on an electronic portal imaging device and log data analysis for Dynamic WaveArc irradiation.

    Science.gov (United States)

    Hirashima, Hideaki; Miyabe, Yuki; Nakamura, Mitsuhiro; Mukumoto, Nobutaka; Mizowaki, Takashi; Hiraoka, Masahiro

    2018-04-06

    The purpose of this study was to develop a simple verification method for the routine quality assurance (QA) of Dynamic WaveArc (DWA) irradiation using electronic portal imaging device (EPID) images and log data analysis. First, an automatic calibration method utilizing the outermost multileaf collimator (MLC) slits was developed to correct the misalignment between the center of the EPID and the beam axis. Moreover, to verify the detection accuracy of the MLC position according to the EPID images, various positions of the MLC with intentional errors in the range 0.1-1 mm were assessed. Second, to validate the geometric accuracy during DWA irradiation, tests were designed in consideration of three indices. Test 1 evaluated the accuracy of the MLC position. Test 2 assessed dose output consistency with variable dose rate (160-400 MU/min), gantry speed (2.2-6°/s), and ring speed (0.5-2.7°/s). Test 3 validated dose output consistency with variable values of the above parameters plus MLC speed (1.6-4.2 cm/s). All tests were delivered to the EPID and compared with those obtained using a stationary radiation beam with a 0° gantry angle. Irradiation log data were recorded simultaneously. The 0.1-mm intentional error on the MLC position could be detected by the EPID, which is smaller than the EPID pixel size. In Test 1, the MLC slit widths agreed within 0.20 mm of their exposed values. The averaged root-mean-square error (RMSE) of the dose outputs was less than 0.8% in Test 2 and Test 3. Using log data analysis in Test 3, the RMSE between the planned and recorded data was 0.1 mm, 0.12°, and 0.07° for the MLC position, gantry angle, and ring angle, respectively. The proposed method is useful for routine QA of the accuracy of DWA. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  15. Testing, Analysis and Control of Wave Dragon, Wave Energy Converter

    DEFF Research Database (Denmark)

    Tedd, James

    of the incident waves upon a wave device allows the possibility of accurately tuning the power-take off mechanism (the hydro-turbines for the Wave Dragon) to capture more energy. A digital filter method for performing this prediction in real-time with minimal computational effort is presented. Construction...... of digital filters is well known within signal processing, but their use for this application in Wave Energy is new. The filter must be designed carefully as the frequency components of waves travel at different speeds. Research presented in this thesis has advanced the development of the Wave Dragon device...

  16. Fast wave current drive

    International Nuclear Information System (INIS)

    Goree, J.; Ono, M.; Colestock, P.; Horton, R.; McNeill, D.; Park, H.

    1985-07-01

    Fast wave current drive is demonstrated in the Princeton ACT-I toroidal device. The fast Alfven wave, in the range of high ion-cyclotron harmonics, produced 40 A of current from 1 kW of rf power coupled into the plasma by fast wave loop antenna. This wave excites a steady current by damping on the energetic tail of the electron distribution function in the same way as lower-hybrid current drive, except that fast wave current drive is appropriate for higher plasma densities

  17. Slow wave cyclotron maser

    International Nuclear Information System (INIS)

    Kho, T.H.; Lin, A.T.

    1988-01-01

    Cyclotron masers such as Gyrotrons and the Autoresonance Masers, are fast wave devices: the electromagnetic wave's phase velocity v rho , is greater than the electron beam velocity, v b . To be able to convert the beam kinetic energy into radiation in these devices the beam must have an initial transverse momentum, usually obtained by propagating the beam through a transverse wiggler magnet, or along a nonuniform guide magnetic field before entry into the interaction region. Either process introduces a significant amount of thermal spread in the beam which degrades the performance of the maser. However, if the wave phase velocity v rho v b , the beam kinetic energy can be converted directly into radiation without the requirement of an initial transverse beam momentum, making a slow wave cyclotron maser a potentially simpler and more compact device. The authors present the linear and nonlinear physics of the slow wave cyclotron maser and examine its potential for practical application

  18. Assimilation of Wave Imaging Radar Observations for Real-Time Wave-by-Wave Forecasting

    Science.gov (United States)

    Haller, M. C.; Simpson, A. J.; Walker, D. T.; Lynett, P. J.; Pittman, R.; Honegger, D.

    2016-02-01

    It has been shown in various studies that a controls system can dramatically improve Wave Energy Converter (WEC) power production by tuning the device's oscillations to the incoming wave field, as well as protect WEC devices by decoupling them in extreme wave conditions. A requirement of the most efficient controls systems is a phase-resolved, "deterministic" surface elevation profile, alerting the device to what it will experience in the near future. The current study aims to demonstrate a deterministic method of wave forecasting through the pairing of an X-Band marine radar with a predictive Mild Slope Equation (MSE) wave model. Using the radar as a remote sensing technique, the wave field up to 1-4 km surrounding a WEC device can be resolved. Individual waves within the radar scan are imaged through the contrast between high intensity wave faces and low intensity wave troughs. Using a recently developed method, radar images are inverted into the radial component of surface slope, shown in the figure provided using radar data from Newport, Oregon. Then, resolved radial slope images are assimilated into the MSE wave model. This leads to a best-fit model hindcast of the waves within the domain. The hindcast is utilized as an initial condition for wave-by-wave forecasting with a target forecast horizon of 3-5 minutes (tens of wave periods). The methodology is currently being tested with synthetic data and comparisons with field data are imminent.

  19. Power from Ocean Waves.

    Science.gov (United States)

    Newman, J. N.

    1979-01-01

    Discussed is the utilization of surface ocean waves as a potential source of power. Simple and large-scale wave power devices and conversion systems are described. Alternative utilizations, environmental impacts, and future prospects of this alternative energy source are detailed. (BT)

  20. The SSG Wave Energy Converter: Performance, Status and Recent Developments

    Directory of Open Access Journals (Sweden)

    Mariano Buccino

    2012-01-01

    Full Text Available The Sea-wave Slot-cone Generator (SSG is a Wave Energy Converter based on the wave overtopping principle; it employs several reservoirs placed on top of each other, in which the energy of incoming waves is stored as potential energy. Then, the captured water runs through turbines for electricity production. The system works under a wide spectrum of different wave conditions, giving a high overall efficiency. It can be suitable for shoreline and breakwater applications and presents particular advantages, such as sharing structure costs, availability of grid connection and recirculation of water inside the harbor, as the outlet of the turbines is on the rear part of the system. Recently, plans for the SSG pilot installations are in progress at the Svaaheia site (Norway, the port of Hanstholm (Denmark and the port of Garibaldi (Oregon, USA. In the last-mentioned two projects, the Sea-wave Slot-cone Generator technology is integrated into the outer harbor breakwater and jetty reconstruction projects. In the last years extensive studies have been performed on the hydraulic and the structural response of this converter, with the aim of optimizing the design process. The investigations have been conducted by physical model tests and numerical simulations and many results have been published on both conference proceedings and journals. The main scope of this paper is reviewing the most significant findings, to provide the reader with an organic overview on the present status of knowledge.

  1. Synthesis of Numerical Methods for Modeling Wave Energy Converter-Point Absorbers: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.; Yu, Y. H.

    2012-05-01

    During the past few decades, wave energy has received significant attention among all ocean energy formats. Industry has proposed hundreds of prototypes such as an oscillating water column, a point absorber, an overtopping system, and a bottom-hinged system. In particular, many researchers have focused on modeling the floating-point absorber as the technology to extract wave energy. Several modeling methods have been used such as the analytical method, the boundary-integral equation method, the Navier-Stokes equations method, and the empirical method. However, no standardized method has been decided. To assist the development of wave energy conversion technologies, this report reviews the methods for modeling the floating-point absorber.

  2. Overtopping of Berm Breakwaters Evaluation of Overtopping Formula

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, H. F.

    2005-01-01

    The berm breakwater concept is basicly rather old, but was not used very much until it was “reinvented” in the early 1980’ties, when a slope protection for an airfield runway extending into the sea in the Alutian Islands, Alaska was designed.......The berm breakwater concept is basicly rather old, but was not used very much until it was “reinvented” in the early 1980’ties, when a slope protection for an airfield runway extending into the sea in the Alutian Islands, Alaska was designed....

  3. Numerical simulation of multi-directional random wave transformation in a yacht port

    Science.gov (United States)

    Ji, Qiaoling; Dong, Sheng; Zhao, Xizeng; Zhang, Guowei

    2012-09-01

    This paper extends a prediction model for multi-directional random wave transformation based on an energy balance equation by Mase with the consideration of wave shoaling, refraction, diffraction, reflection and breaking. This numerical model is improved by 1) introducing Wen's frequency spectrum and Mitsuyasu's directional function, which are more suitable to the coastal area of China; 2) considering energy dissipation caused by bottom friction, which ensures more accurate results for large-scale and shallow water areas; 3) taking into account a non-linear dispersion relation. Predictions using the extended wave model are carried out to study the feasibility of constructing the Ai Hua yacht port in Qingdao, China, with a comparison between two port layouts in design. Wave fields inside the port for different incident wave directions, water levels and return periods are simulated, and then two kinds of parameters are calculated to evaluate the wave conditions for the two layouts. Analyses show that Layout I is better than Layout II. Calculation results also show that the harbor will be calm for different wave directions under the design water level. On the contrary, the wave conditions do not wholly meet the requirements of a yacht port for ship berthing under the extreme water level. For safety consideration, the elevation of the breakwater might need to be properly increased to prevent wave overtopping under such water level. The extended numerical simulation model may provide an effective approach to computing wave heights in a harbor.

  4. A scattering approach to sea wave diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Corradini, M. L., E-mail: letizia.corradini@unicam.it; Garbuglia, M., E-mail: milena.garbuglia@unicam.it; Maponi, P., E-mail: pierluigi.maponi@unicam.it [University of Camerino, via Madonna delle Carceri, 9, 62032, Camerino (Italy); Ruggeri, M., E-mail: ru.marco@faggiolatipumps.it [Faggiolati Pumps S.p.A., Z.Ind Sforzacosta, 62100, Macerata (Italy)

    2016-06-08

    This paper intends to show a model for the diffraction of sea waves approaching an OWC device, which converts the sea waves motion into mechanical energy and then electrical energy. This is a preliminary study to the optimisation of the device, in fact the computation of sea waves diffraction around the device allows the estimation of the sea waves energy which enters into the device. The computation of the diffraction phenomenon is the result of a sea waves scattering problem, solved with an integral equation method.

  5. Benefits of up-wave measurements in linear short-term wave forecasting for wave energy applications

    OpenAIRE

    Paparella, Francesco; Monk, Kieran; Winands, Victor; Lopes, Miguel; Conley, Daniel; Ringwood, John

    2014-01-01

    The real-time control of wave energy converters requires the prediction of the wave elevation at the location of the device in order to maximize the power extracted from the waves. One possibility is to predict the future wave elevation by combining its past history with the spatial information coming from a sensor which measures the free surface elevation upwave of the wave energy converter. As an application example, the paper focuses on the prediction of the wave eleva...

  6. Experimental Study on the WavePiston Wave Energy Converter

    DEFF Research Database (Denmark)

    Pecher, Arthur; Kofoed, Jens Peter; Angelelli, E.

    This report presents the results of an experimental study of the power performance of the WavePiston wave energy converter. It focuses mainly on evaluating the power generating capabilities of the device and the effect of the following issues: Scaling ratios PTO loading Wave height and wave period...... dependency Oblique incoming waves Distance between plates During the study, the model supplied by the client, WavePiston, has been rigorously tested as all the anticipated tests have been done thoroughly and during all tests, good quality data has been obtained from all the sensors....

  7. Technology's Latest Wave: Colleges and Universities Are Increasingly Exploring the Academic Use of Digital Mobile Devices-But Lack of Money Sometimes Stands in the Way

    Science.gov (United States)

    Galuszka, Peter

    2005-01-01

    Using mobile digital devices--iPods, personal digital assistants (PDAs), Tablet PCs or advanced cell phones--is becoming a big campus trend. Their advantages include convenience and the ability to hear lectures or course-related music just about anywhere. PDA's such as Palm Pilots and BlackBerrys, iPods such as Apple's and Tablet PCs, including…

  8. A physical based equivalent circuit modeling approach for ballasted InP DHBT multi-finger devices at millimeter-wave frequencies

    DEFF Research Database (Denmark)

    Midili, Virginio; Squartecchia, Michele; Johansen, Tom Keinicke

    2016-01-01

    equivalent circuit description. In the first approach, the EM simulations of contact pads and ballasting network are combined with the small-signal model of the intrinsic device. In the second approach, the ballasting network is modeled with lumped components derived from physical analysis of the layout...

  9. Development of the 'SEA-Clam' wave energy device for small scale use. Report for period 1st August 1983 - 31st March 1985

    Energy Technology Data Exchange (ETDEWEB)

    1985-03-01

    The Report presented covers the work of the Sea Energy Associates Ltd./Coventry (Lanchester) Polytechnic Wave Energy Group on the development of the SEA Clam concept from a 290 metre long, 45 000 tonne displacement unit rated at 10 MW to a smaller unit, typically 500 to 1000 kW, for island or remote coastal communities. Productivity measurements, flexible bag development, and work on the Wells' turbine which has been concentrated on the outline design and costing of an engineered unit for this application are discussed.

  10. Millimeter-wave receiver design for plasma diagnostics

    DEFF Research Database (Denmark)

    Leipold, Frank; Hansen, S. K.; Jacobsen, Asger Schou

    2016-01-01

    Scattered millimeter waves entering from the collective Thomson scattering diagnostic at ASDEX Upgrade fusion device are generally elliptically polarized. In order to convert the millimeter waves to linearly polarized waves (required for the detector), birefringent window assemblies (sapphire) ha...

  11. High frequency jet ventilation through a supraglottic airway device: a case series of patients undergoing extra-corporeal shock wave lithotripsy.

    Science.gov (United States)

    Canty, D J; Dhara, S S

    2009-12-01

    High frequency jet ventilation has been shown to be beneficial during extra-corporeal shock wave lithotripsy as it reduces urinary calculus movement which increases lithotripsy efficiency with better utilisation of shockwave energy and less patient exposure to tissue trauma. In all reports, sub-glottic high frequency jet ventilation was delivered through a tracheal tube or a jet catheter requiring paralysis and direct laryngoscopy. In this study, a simple method using supraglottic jet ventilation through a laryngeal mask attached to a circle absorber anaesthetic breathing system is described. The technique avoids the need for dense neuromuscular blockade for laryngoscopy and the potential complications associated with sub-glottic instrumentation and sub-glottic jet ventilation. The technique was successfully employed in a series of patients undergoing lithotripsy under general anaesthesia as an outpatient procedure.

  12. Making waves in Australia

    International Nuclear Information System (INIS)

    Perera, Judith

    1999-01-01

    The advantages of using wave power as a renewable energy source are discussed. Various methods of harnessing wave power are also discussed, together with investment requirements and the relative costs of producing electricity by other means. Island communities who currently rely on imported diesel are interested. The provision of power for reverse osmosis plants producing drinking water is an attractive application. There are many potential devices but the best way forward has yet to be identified. (UK)

  13. Modeling storm waves

    International Nuclear Information System (INIS)

    Benoit, M.; Marcos, F.; Teisson, Ch.

    1999-01-01

    Nuclear power stations located on the coast take the water they use to cool their circuits from the sea. The water intake and discharge devices must be able to operate in all weathers, notably during extreme storms, with waves 10 m high and over. To predict the impact of the waves on the equipment, they are modeled digitally from the moment they form in the middle of the ocean right up to the moment they break on the shore. (authors)

  14. Surface Effects and Challenges for Application of Piezoelectric Langasite Substrates in Surface Acoustic Wave Devices Caused by High Temperature Annealing under High Vacuum.

    Science.gov (United States)

    Seifert, Marietta; Rane, Gayatri K; Kirbus, Benjamin; Menzel, Siegfried B; Gemming, Thomas

    2015-12-19

    Substrate materials that are high-temperature stable are essential for sensor devices which are applied at high temperatures. Although langasite is suggested as such a material, severe O and Ga diffusion into an O-affine deposited film was observed during annealing at high temperatures under vacuum conditions, leading to a damage of the metallization as well as a change of the properties of the substrate and finally to a failure of the device. Therefore, annealing of bare LGS (La 3 Ga 5 SiO 14 ) substrates at 800 ∘ C under high vacuum conditions is performed to analyze whether this pretreatment improves the suitability and stability of this material for high temperature applications in vacuum. To reveal the influence of the pretreatment on the subsequently deposited metallization, RuAl thin films are used as they are known to oxidize on LGS at high temperatures. A local study of the pretreated and metallized substrates using transmission electron microscopy reveals strong modification of the substrate surface. Micro cracks are visible. The composition of the substrate is strongly altered at those regions. Severe challenges for the application of LGS substrates under high-temperature vacuum conditions arise from these substrate damages, revealing that the pretreatment does not improve the applicability.

  15. Surface Effects and Challenges for Application of Piezoelectric Langasite Substrates in Surface Acoustic Wave Devices Caused by High Temperature Annealing under High Vacuum

    Directory of Open Access Journals (Sweden)

    Marietta Seifert

    2015-12-01

    Full Text Available Substrate materials that are high-temperature stable are essential for sensor devices which are applied at high temperatures. Although langasite is suggested as such a material, severe O and Ga diffusion into an O-affine deposited film was observed during annealing at high temperatures under vacuum conditions, leading to a damage of the metallization as well as a change of the properties of the substrate and finally to a failure of the device. Therefore, annealing of bare LGS (La 3 Ga 5 SiO 14 substrates at 800 ∘ C under high vacuum conditions is performed to analyze whether this pretreatment improves the suitability and stability of this material for high temperature applications in vacuum. To reveal the influence of the pretreatment on the subsequently deposited metallization, RuAl thin films are used as they are known to oxidize on LGS at high temperatures. A local study of the pretreated and metallized substrates using transmission electron microscopy reveals strong modification of the substrate surface. Micro cracks are visible. The composition of the substrate is strongly altered at those regions. Severe challenges for the application of LGS substrates under high-temperature vacuum conditions arise from these substrate damages, revealing that the pretreatment does not improve the applicability.

  16. Spin-Wave Diode

    Directory of Open Access Journals (Sweden)

    Jin Lan (兰金

    2015-12-01

    Full Text Available A diode, a device allowing unidirectional signal transmission, is a fundamental element of logic structures, and it lies at the heart of modern information systems. The spin wave or magnon, representing a collective quasiparticle excitation of the magnetic order in magnetic materials, is a promising candidate for an information carrier for the next-generation energy-saving technologies. Here, we propose a scalable and reprogrammable pure spin-wave logic hardware architecture using domain walls and surface anisotropy stripes as waveguides on a single magnetic wafer. We demonstrate theoretically the design principle of the simplest logic component, a spin-wave diode, utilizing the chiral bound states in a magnetic domain wall with a Dzyaloshinskii-Moriya interaction, and confirm its performance through micromagnetic simulations. Our findings open a new vista for realizing different types of pure spin-wave logic components and finally achieving an energy-efficient and hardware-reprogrammable spin-wave computer.

  17. Simulations of High Harmonic Fast Wave Heating on the C-2U Advanced Beam-Driven Field-Reversed Configuration Device

    Science.gov (United States)

    Yang, Xiaokang; Petrov, Yuri; Ceccherini, Francesco; Koehn, Alf; Galeotti, Laura; Dettrick, Sean; Binderbauer, Michl

    2017-10-01

    Numerous efforts have been made at Tri-Alpha Energy (TAE) to theoretically explore the physics of microwave electron heating in field-reversed configuration (FRC) plasmas. For the fixed 2D profiles of plasma density and temperature for both electrons and thermal ions and equilibrium field of the C-2U machine, simulations with GENRAY-C ray-tracing code have been conducted for the ratios of ω/ωci[D] in the range of 6 - 20. Launch angles and antenna radial and axial positions have been optimized in order to simultaneously achieve good wave penetration into the core of FRC plasmas and efficient power damping on electrons. It is found that in an optimal regime, single pass absorption efficiency is 100% and most of the power is deposited inside the separatrix of FRC plasmas, with power damping efficiency of about 72% on electrons and less than 19% on ions. Calculations have clearly demonstrated that substantial power absorption on electrons is mainly attributed to high beta enhancement of magnetic pumping; complete power damping occurs before Landau damping has a significant effect on power absorption.

  18. Simulations of High Harmonic Fast Wave Heating on the C-2U Advanced Beam-Driven Field-Reversed Configuration Device

    Directory of Open Access Journals (Sweden)

    Yang Xiaokang

    2017-01-01

    Full Text Available Numerous efforts have been made at Tri-Alpha Energy (TAE to theoretically explore the physics of microwave electron heating in field-reversed configuration (FRC plasmas. For the fixed 2D profiles of plasma density and temperature for both electrons and thermal ions and equilibrium field of the C-2U machine, simulations with GENRAY-C ray-tracing code have been conducted for the ratios of ω/ωci[D] in the range of 6 - 20. Launch angles and antenna radial and axial positions have been optimized in order to simultaneously achieve good wave penetration into the core of FRC plasmas and efficient power damping on electrons. It is found that in an optimal regime, single pass absorption efficiency is 100% and most of the power is deposited inside the separatrix of FRC plasmas, with power damping efficiency of about 72% on electrons and less than 19% on ions. Calculations have clearly demonstrated that substantial power absorption on electrons is mainly attributed to high beta enhancement of magnetic pumping; complete power damping occurs before Landau damping has a significant effect on power absorption.

  19. Coherent Wave Measurement Buoy Arrays to Support Wave Energy Extraction

    Science.gov (United States)

    Spada, F.; Chang, G.; Jones, C.; Janssen, T. T.; Barney, P.; Roberts, J.

    2016-02-01

    Wave energy is the most abundant form of hydrokinetic energy in the United States and wave energy converters (WECs) are being developed to extract the maximum possible power from the prevailing wave climate. However, maximum wave energy capture is currently limited by the narrow banded frequency response of WECs as well as extended protective shutdown requirements during periods of large waves. These limitations must be overcome in order to maximize energy extraction, thus significantly decreasing the cost of wave energy and making it a viable energy source. Techno-economic studies of several WEC devices have shown significant potential to improve wave energy capture efficiency through operational control strategies that incorporate real-time information about local surface wave motions. Integral Consulting Inc., with ARPA-E support, is partnering with Sandia National Laboratories and Spoondrift LLC to develop a coherent array of wave-measuring devices to relay and enable the prediction of wave-resolved surface dynamics at a WEC location ahead of real time. This capability will provide necessary information to optimize power production of WECs through control strategies, thereby allowing for a single WEC design to perform more effectively across a wide range of wave environments. The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000514.

  20. Wave Induced Loads on the LEANCON Wave Energy Converter

    DEFF Research Database (Denmark)

    Frigaard, Peter; Kofoed, Jens Peter; Beserra, Eliab Ricarte

    This report is a product of the co-operation agreement between Aalborg University and LEANCON (by Kurt Due Rasmussen) on the evaluation and development of the LEANCON wave energy converter (WEC). The work reported here has focused on evaluation of the wave induced loads on the device, based...... in the laboratory, all under the supervision of the personnel of the Wave Energy Research Group at Department of Civil Engineering, Aalborg University....

  1. Sea testing and optimisation of power production on a scale 1:4.5 test rig of the offshore wave energy converter wave dragon. Summary of final technical report

    Energy Technology Data Exchange (ETDEWEB)

    2006-06-15

    The 4-11 MW Wave Dragon is a slack moored device that can be deployed in large parks wherever a sufficient wave climate and a water depth of more than 20 m is found--typically this is the case in the North Sea and in the Atlantic, offering significant economic and environmental benefits for the EU. The primary objective of the project was to establish the scientific knowledge base needed for deploying a full-scale prototype of the overtopping wave energy converter Wave Dragon. This has been obtained through long-term field-testing on a test rig with all systems installed. The scale 1:4.5 prototype has an installed power of 20 kW corresponding to 4 MW in full-scale with full-turbine deployment and is grid connected. The scale 1:4.5 prototype has been designed based on the conclusions from a previous EU Craft project. The basic test rig construction is provided through a project sponsored by the Danish Energy Authority. The test site is in protected waters in Nissum Bredning, Denmark, where the wave climate resembles North Sea conditions (scale 1:4.5) which in accordance with model law resembles a power scale of 1:200. The test results after more than 20,000 hours of operation cover: Long-term field testing of turbine operation, control strategy testing and optimisation, power monitoring and evaluation, stress and strain measurements and analysis, and mooring and cable systems analysis. The model tools developed in the previous EU Craft project have been validated and slightly modified based on the measured data. A Life Cycle Analysis and Finite Element Modelling have been performed. A report on market analysis, economic risk assessment and job creation potential has also been carried out. The project has established the necessary scientific and technical knowledge base for engaging in the establishment of a full-scale prototype in exposed waters. This includes the existence of a well-established design basis and documentation of technical viability through long

  2. Investigation of Wave Height Reduction behind the Wave Dragon Wave Energy Converters and Application in Santander, Spain

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Quvang Harck; Andersen, Thomas Lykke

    This paper deals with a case study on the wave height reduction behind floating Wave Dragon wave energy converters in Santander Bay, Spain. The study is performed using the MIKE21 Boussinesq model from DHI. The Wave Dragon transmission characteristics in the numerical wave propagation model...... are based on previously performed physical model tests in scale 1:51. Typical winter storm conditions are considered in the case study together with different stiffness in the mooring system of the floating device. From the study it is found that if multiple Wave Dragons are positioned in a farm the wave...

  3. Experiments on the WavePiston, Wave Energy Converter

    DEFF Research Database (Denmark)

    Angelelli, E.; Zanuttigh, B.; Kofoed, Jens Peter

    2011-01-01

    This paper analyses the performance of a new Wave Energy Converter (WEC) of the Oscillating Water Column type (OWC), named WavePiston. This near-shore floating device is composed of plates (i.e. energy collectors) sliding around a cylinder, that is placed perpendicular to the shore. Tests...... in the wave basin at Aalborg University allowed to investigate power production in the North Sea typical wave climate, with varying design parameters such as plate dimensions and their mutual distance. The power produced per meter by each collector is about the 5% of the available wave power. Experimental...... results and survivability considerations suggest that the WavePiston would be particularly suited for installations in milder seas. An example application is therefore presented in the Mediterranean Sea, off-shore the island of Sicily. In this case, each collector harvests the 10% of the available wave...

  4. Design Specifications for the Hanstholm WEPTOS Wave Energy Converter

    DEFF Research Database (Denmark)

    Pecher, Arthur; Kofoed, Jens Peter; Larsen, Tommy

    2012-01-01

    The WEPTOS wave energy converter (WEC) is a novel device that combines an established and efficient wave energy absorbing mechanism with a smart structure, which can regulate the amount of incoming wave energy and reduce loads in extreme wave conditions. This adjustable A-shaped slack-moored and ......The WEPTOS wave energy converter (WEC) is a novel device that combines an established and efficient wave energy absorbing mechanism with a smart structure, which can regulate the amount of incoming wave energy and reduce loads in extreme wave conditions. This adjustable A-shaped slack...

  5. Topology optimization of wave-propagation problems

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard; Sigmund, Ole

    2006-01-01

    Topology optimization is demonstrated as a useful tool for systematic design of wave-propagation problems. We illustrate the applicability of the method for optical, acoustic and elastic devices and structures.......Topology optimization is demonstrated as a useful tool for systematic design of wave-propagation problems. We illustrate the applicability of the method for optical, acoustic and elastic devices and structures....

  6. Variability In Long-Wave Runup as a Function of Nearshore Bathymetric Features

    Energy Technology Data Exchange (ETDEWEB)

    Dunkin, Lauren McNeill [Texas A & M Univ., College Station, TX (United States)

    2010-05-01

    Beaches and barrier islands are vulnerable to extreme storm events, such as hurricanes, that can cause severe erosion and overwash to the system. Having dunes and a wide beach in front of coastal infrastructure can provide protection during a storm, but the influence that nearshore bathymetric features have in protecting the beach and barrier island system is not completely understood. The spatial variation in nearshore features, such as sand bars and beach cusps, can alter nearshore hydrodynamics, including wave setup and runup. The influence of bathymetric features on long-wave runup can be used in evaluating the vulnerability of coastal regions to erosion and dune overtopping, evaluating the changing morphology, and implementing plans to protect infrastructure. In this thesis, long-wave runup variation due to changing bathymetric features as determined with the numerical model XBeach is quantified (eXtreme Beach behavior model). Wave heights are analyzed to determine the energy through the surfzone. XBeach assumes that coastal erosion at the land-sea interface is dominated by bound long-wave processes. Several hydrodynamic conditions are used to force the numerical model. The XBeach simulation results suggest that bathymetric irregularity induces significant changes in the extreme long-wave runup at the beach and the energy indicator through the surfzone.

  7. Proposed electromagnetic wave energy converter

    Science.gov (United States)

    Bailey, R. L.

    1973-01-01

    Device converts wave energy into electric power through array of insulated absorber elements responsive to field of impinging electromagnetic radiation. Device could also serve as solar energy converter that is potentially less expensive and fragile than solar cells, yet substantially more efficient.

  8. Riding the ocean waves

    International Nuclear Information System (INIS)

    Yemm, Richard

    2000-01-01

    It is claimed that important developments over the past five years mean that there will be a range of competing pre-commercial wave-energy systems by 2002. The generation costs should be on a par with biomass schemes and offshore wind systems. The environmental advantages of wave energy are extolled. Ocean Power Delivery (OPD) have produced a set of criteria to be satisfied for a successful wave power scheme and these are listed. OPD is responsible for the snake-like Pelamis device which is a semi-submerged articulated series of cylindrical sections connected through hinged joints. How the wave-induced movement of the hinges is used to generate electricity is explained. The system is easily installed and can be completely removed at the end of its life

  9. Turbulence generation by waves

    Energy Technology Data Exchange (ETDEWEB)

    Kaftori, D.; Nan, X.S.; Banerjee, S. [Univ. of California, Santa Barbara, CA (United States)

    1995-12-31

    The interaction between two-dimensional mechanically generated waves, and a turbulent stream was investigated experimentally in a horizontal channel, using a 3-D LDA synchronized with a surface position measuring device and a micro-bubble tracers flow visualization with high speed video. Results show that although the wave induced orbital motion reached all the way to the wall, the characteristics of the turbulence wall structures and the turbulence intensity close to the wall were not altered. Nor was the streaky nature of the wall layer. On the other hand, the mean velocity profile became more uniform and the mean friction velocity was increased. Close to the free surface, the turbulence intensity was substantially increased as well. Even in predominantly laminar flows, the introduction of 2-D waves causes three dimensional turbulence. The turbulence enhancement is found to be proportional to the wave strength.

  10. Optical analog transmission device

    International Nuclear Information System (INIS)

    Ikawa, Shinji.

    1994-01-01

    The present invention concerns a device such as electro-optical conversion elements, optoelectric-electric elements and optical transmission channel, not undergoing deleterious effects on the efficiency of conversion and transmission due to temperature, and aging change. That is, a sine wave superposing means superposes, on a detector signal to be transmitted, a sine-wave signal having a predetermined amplitude and at a frequency lower than that of the detector signal. An optoelectric conversion means converts the electric signal as the signal of the sine-wave signal superposing means into an optical signal and outputs the same to an optical transmitting channel. The optoelectric conversion means converts the transmitted signal to an electric signal. A discriminating means discriminates the electric signal into a detector signal and a sine-wave signal. A calculating means calculates an optical transmitting efficiency of the transmitting channel based on the amplitude of the discriminated sine-wave signal. A processing means compensates an amplitude value of the detector signals discriminated by the discriminating means based on the optical transmission efficiency. As a result, an optical analog transmission device can be attained, which conducts optical transmission at a high accuracy without undergoing the defective effects of the optical transmission efficiency. (I.S.)

  11. 3D SPH numerical simulation of the wave generated by the Vajont rockslide

    Science.gov (United States)

    Vacondio, R.; Mignosa, P.; Pagani, S.

    2013-09-01

    A 3D numerical modeling of the wave generated by the Vajont slide, one of the most destructive ever occurred, is presented in this paper. A meshless Lagrangian Smoothed Particle Hydrodynamics (SPH) technique was adopted to simulate the highly fragmented violent flow generated by the falling slide in the artificial reservoir. The speed-up achievable via General Purpose Graphic Processing Units (GP-GPU) allowed to adopt the adequate resolution to describe the phenomenon. The comparison with the data available in literature showed that the results of the numerical simulation reproduce satisfactorily the maximum run-up, also the water surface elevation in the residual lake after the event. Moreover, the 3D velocity field of the flow during the event and the discharge hydrograph which overtopped the dam, were obtained.

  12. Incore monitoring device

    International Nuclear Information System (INIS)

    Tai, Ichiro; Shirayama, Shin-pei; Nozaki, Shin-ichi.

    1978-01-01

    Purpose: To provide an incore monitoring device wherein both radiation monitoring and acoustic monitoring are carried out simultaneously by one detector, whereby installation of the device and signal pick-up are facilitated. Incore conditions are accurately grasped. Constitution: When a neutron is irradiated in a state where a DC voltage is applied between the electrode and the vessel in the device, an ionization current is occured by (n.γ) reaction of the transformed substance as in an ionization chamber, Accordingly, a voltage drop occurs at both ends of the resistor of the radiation signal processing system, as a result of which a neutron flux can be detected. Further, when a sound is generated in the reactor, the monitoring device bottom wall which formed by a piezoelectric element detects the sound-waves. This output signal is picked up by the acoustic signal processing system to judge the generation of sound. (Aizawa, K.)

  13. Plasma waves

    CERN Document Server

    Swanson, DG

    1989-01-01

    Plasma Waves discusses the basic development and equations for the many aspects of plasma waves. The book is organized into two major parts, examining both linear and nonlinear plasma waves in the eight chapters it encompasses. After briefly discussing the properties and applications of plasma wave, the book goes on examining the wave types in a cold, magnetized plasma and the general forms of the dispersion relation that characterize the waves and label the various types of solutions. Chapters 3 and 4 analyze the acoustic phenomena through the fluid model of plasma and the kinetic effects. Th

  14. Heat Waves

    Science.gov (United States)

    Heat Waves Dangers we face during periods of very high temperatures include: Heat cramps: These are muscular pains and spasms due ... that the body is having trouble with the heat. If a heat wave is predicted or happening… - ...

  15. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Brorsen, Michael; Frigaard, Peter

    Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star.......Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star....

  16. Gravitational Waves

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Jonah Maxwell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-18

    This report has slides on Gravitational Waves; Pound and Rebka: A Shocking Fact; Light is a Ruler; Gravity is the Curvature of Spacetime; Gravitational Waves Made Simple; How a Gravitational Wave Affects Stuff Here; LIGO; This Detection: Neutron Stars; What the Gravitational Wave Looks Like; The Sound of Merging Neutron Stars; Neutron Star Mergers: More than GWs; The Radioactive Cloud; The Kilonova; and finally Summary, Multimessenger Astronomy.

  17. Stress wave focusing transducers

    Energy Technology Data Exchange (ETDEWEB)

    Visuri, S.R., LLNL

    1998-05-15

    Conversion of laser radiation to mechanical energy is the fundamental process behind many medical laser procedures, particularly those involving tissue destruction and removal. Stress waves can be generated with laser radiation in several ways: creation of a plasma and subsequent launch of a shock wave, thermoelastic expansion of the target tissue, vapor bubble collapse, and ablation recoil. Thermoelastic generation of stress waves generally requires short laser pulse durations and high energy density. Thermoelastic stress waves can be formed when the laser pulse duration is shorter than the acoustic transit time of the material: {tau}{sub c} = d/c{sub s} where d = absorption depth or spot diameter, whichever is smaller, and c{sub s} = sound speed in the material. The stress wave due to thermoelastic expansion travels at the sound speed (approximately 1500 m/s in tissue) and leaves the site of irradiation well before subsequent thermal events can be initiated. These stress waves, often evolving into shock waves, can be used to disrupt tissue. Shock waves are used in ophthalmology to perform intraocular microsurgery and photodisruptive procedures as well as in lithotripsy to fragment stones. We have explored a variety of transducers that can efficiently convert optical to mechanical energy. One such class of transducers allows a shock wave to be focused within a material such that the stress magnitude can be greatly increased compared to conventional geometries. Some transducer tips could be made to operate regardless of the absorption properties of the ambient media. The size and nature of the devices enable easy delivery, potentially minimally-invasive procedures, and precise tissue- targeting while limiting thermal loading. The transducer tips may have applications in lithotripsy, ophthalmology, drug delivery, and cardiology.

  18. Wave phenomena

    CERN Document Server

    Towne, Dudley H

    1988-01-01

    This excellent undergraduate-level text emphasizes optics and acoustics, covering inductive derivation of the equation for transverse waves on a string, acoustic plane waves, boundary-value problems, polarization, three-dimensional waves and more. With numerous problems (solutions for about half). ""The material is superbly chosen and brilliantly written"" - Physics Today. Problems. Appendices.

  19. Electromagnetic Waves

    DEFF Research Database (Denmark)

    This book is dedicated to various aspects of electromagnetic wave theory and its applications in science and technology. The covered topics include the fundamental physics of electromagnetic waves, theory of electromagnetic wave propagation and scattering, methods of computational analysis......, material characterization, electromagnetic properties of plasma, analysis and applications of periodic structures and waveguide components, etc....

  20. Gas dynamic laser device

    International Nuclear Information System (INIS)

    Born, G.

    1975-01-01

    The gas dynamic laser device is provided with an expansion chamber arranged between a heating chamber for the CO-gas and the resonance chamber. The expansion chamber is initially evacuated for producing a rarefaction wave. Between the heating chamber and the expansion chamber there are arranged rapid release means such as a valve or a diaphragm. Pressure recovering means are connected to the other side of the resonance chamber

  1. Calcium waves.

    Science.gov (United States)

    Jaffe, Lionel F

    2008-04-12

    Waves through living systems are best characterized by their speeds at 20 degrees C. These speeds vary from those of calcium action potentials to those of ultraslow ones which move at 1-10 and/or 10-20 nm s(-1). All such waves are known or inferred to be calcium waves. The two classes of calcium waves which include ones with important morphogenetic effects are slow waves that move at 0.2-2 microm s(-1) and ultraslow ones. Both may be propagated by cycles in which the entry of calcium through the plasma membrane induces subsurface contraction. This contraction opens nearby stretch-sensitive calcium channels. Calcium entry through these channels propagates the calcium wave. Many slow waves are seen as waves of indentation. Some are considered to act via cellular peristalsis; for example, those which seem to drive the germ plasm to the vegetal pole of the Xenopus egg. Other good examples of morphogenetic slow waves are ones through fertilizing maize eggs, through developing barnacle eggs and through axolotl embryos during neural induction. Good examples of ultraslow morphogenetic waves are ones during inversion in developing Volvox embryos and across developing Drosophila eye discs. Morphogenetic waves may be best pursued by imaging their calcium with aequorins.

  2. Wave turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Nazarenko, Sergey [Warwick Univ., Coventry (United Kingdom). Mathematics Inst.

    2011-07-01

    Wave Turbulence refers to the statistical theory of weakly nonlinear dispersive waves. There is a wide and growing spectrum of physical applications, ranging from sea waves, to plasma waves, to superfluid turbulence, to nonlinear optics and Bose-Einstein condensates. Beyond the fundamentals the book thus also covers new developments such as the interaction of random waves with coherent structures (vortices, solitons, wave breaks), inverse cascades leading to condensation and the transitions between weak and strong turbulence, turbulence intermittency as well as finite system size effects, such as ''frozen'' turbulence, discrete wave resonances and avalanche-type energy cascades. This book is an outgrow of several lectures courses held by the author and, as a result, written and structured rather as a graduate text than a monograph, with many exercises and solutions offered along the way. The present compact description primarily addresses students and non-specialist researchers wishing to enter and work in this field. (orig.)

  3. Photovoltaic device

    Energy Technology Data Exchange (ETDEWEB)

    Reese, Jason A; Keenihan, James R; Gaston, Ryan S; Kauffmann, Keith L; Langmaid, Joseph A; Lopez, Leonardo; Maak, Kevin D; Mills, Michael E; Ramesh, Narayan; Teli, Samar R

    2017-03-21

    The present invention is premised upon an improved photovoltaic device ("PV device"), more particularly to an improved photovoltaic device with a multilayered photovoltaic cell assembly and a body portion joined at an interface region and including an intermediate layer, at least one interconnecting structural member, relieving feature, unique component geometry, or any combination thereof.

  4. Photovoltaic device

    Science.gov (United States)

    Reese, Jason A.; Keenihan, James R.; Gaston, Ryan S.; Kauffmann, Keith L.; Langmaid, Joseph A.; Lopez, Leonardo C.; Maak, Kevin D.; Mills, Michael E.; Ramesh, Narayan; Teli, Samar R.

    2015-06-02

    The present invention is premised upon an improved photovoltaic device ("PV device"), more particularly to an improved photovoltaic device with a multilayered photovoltaic cell assembly and a body portion joined at an interface region and including an intermediate layer, at least one interconnecting structural member, relieving feature, unique component geometry, or any combination thereof.

  5. Photovoltaic device

    Science.gov (United States)

    Reese, Jason A.; Keenihan, James R.; Gaston, Ryan S.; Kauffmann, Keith L.; Langmaid, Joseph A.; Lopez, Leonardo C.; Maak, Kevin D.; Mills, Michael E.; Ramesh, Narayan; Teli, Samar R.

    2015-09-01

    The present invention is premised upon an improved photovoltaic device ("PV device"), more particularly to an improved photovoltaic device (10) with a multilayered photovoltaic cell assembly (100) and a body portion (200) joined at an interface region (410) and including an intermediate layer (500), at least one interconnecting structural member (1500), relieving feature (2500), unique component geometry, or any combination thereof.

  6. Integrated Ultrasonic-Photonic Devices

    DEFF Research Database (Denmark)

    Barretto, Elaine Cristina Saraiva

    in channel waveguides and Mach-Zehnder interferometers. Numerical models are developed based on the finite element method, and applied to several scenarios, such as optimization of the geometrical parameters of waveguides, use of slow light in photonic crystal waveguides and use of Lamb waves in membranized......This thesis deals with the modeling, design, fabrication and characterization of integrated ultrasonic-photonic devices, with particular focus on the use of standard semiconductor materials such as GaAs and silicon. The devices are based on the use of guided acoustic waves to modulate the light...... investigated. Comparisons are made with the numerical and experimental results, and they validate the obtained response of the acoustic and photonic components of the device. Finally, a new design for an optical frequency shifter is proposed, posing several advantages over existing devices in terms of size...

  7. Gravitation Waves

    CERN Multimedia

    CERN. Geneva

    2005-01-01

    We will present a brief introduction to the physics of gravitational waves and their properties. We will review potential astrophysical sources of gravitational waves, and the physics and astrophysics that can be learned from their study. We will survey the techniques and technologies for detecting gravitational waves for the first time, including bar detectors and broadband interferometers, and give a brief status report on the international search effort, with special emphasis on the LIGO detectors and search results.

  8. On Emulation of Flueric Devices in Excitable Chemical Medium.

    Directory of Open Access Journals (Sweden)

    Andrew Adamatzky

    Full Text Available Flueric devices are fluidic devices without moving parts. Fluidic devices use fluid as a medium for information transfer and computation. A Belousov-Zhabotinsky (BZ medium is a thin-layer spatially extended excitable chemical medium which exhibits travelling excitation wave-fronts. The excitation wave-fronts transfer information. Flueric devices compute via jets interaction. BZ devices compute via excitation wave-fronts interaction. In numerical model of BZ medium we show that functions of key flueric devices are implemented in the excitable chemical system: signal generator, and, xor, not and nor Boolean gates, delay elements, diodes and sensors. Flueric devices have been widely used in industry since late 1960s and are still employed in automotive and aircraft technologies. Implementation of analog of the flueric devices in the excitable chemical systems opens doors to further applications of excitation wave-based unconventional computing in soft robotics, embedded organic electronics and living technologies.

  9. On Emulation of Flueric Devices in Excitable Chemical Medium.

    Science.gov (United States)

    Adamatzky, Andrew

    2016-01-01

    Flueric devices are fluidic devices without moving parts. Fluidic devices use fluid as a medium for information transfer and computation. A Belousov-Zhabotinsky (BZ) medium is a thin-layer spatially extended excitable chemical medium which exhibits travelling excitation wave-fronts. The excitation wave-fronts transfer information. Flueric devices compute via jets interaction. BZ devices compute via excitation wave-fronts interaction. In numerical model of BZ medium we show that functions of key flueric devices are implemented in the excitable chemical system: signal generator, and, xor, not and nor Boolean gates, delay elements, diodes and sensors. Flueric devices have been widely used in industry since late 1960s and are still employed in automotive and aircraft technologies. Implementation of analog of the flueric devices in the excitable chemical systems opens doors to further applications of excitation wave-based unconventional computing in soft robotics, embedded organic electronics and living technologies.

  10. Wave energy for the 21st century: status and prospects

    International Nuclear Information System (INIS)

    Thorpe, Tom

    2000-01-01

    This article reviews the current technical and commercial status of wave energy, and discusses the design of near shore devices such as the 2MW OSPREY, and offshore devices including the McCabe wave pump, the Ocean Power Technology Wave Energy Converter, the Archimedes Wave Swing, the Pelamis, and wave energy schemes under development by other commercial firms. The predicted generating costs, the potential market, environmental impacts, and institution factors such as planning and consent, grid connection,and safety in design and operation are considered. The operating principles of an oscillating water column, and some promising offshore devices are illustrated

  11. Super rogue wave in plasma

    International Nuclear Information System (INIS)

    Pathak, Pallabi; Sharma, Sumita Kumari; Bailung, Heremba

    2015-01-01

    The evolution of super rogue wave having amplitude ∼5 times the background wave has been observed in multicomponent plasma with critical concentration of negative ions in a double plasma device. In normal electron-ion plasma the ion acoustic solitons are described by the Korteweg-de Vries (KdV) equation. At a critical concentration of negative ions, the ion acoustic modified KdV solitons are found to propagate. Multicomponent plasma also supports the propagation of a special kind of soliton namely 'Peregrine soliton' at critical concentration of negative ions. Peregrine soliton is a doubly localized solution of the nonlinear Schrodinger equation (NLSE) having amplitude 3 times the background carrier wave. In a double plasma device, ion-acoustic Peregrine soliton is excited by applying slowly varying amplitude modulated continuous sinusoidal signal to the source anode and described by the rational solution of NLSE. The ion acoustic wave is modulationally unstable in multicomponent plasma with critical concentration of negative ions and an initial modulated wave perturbation is found to undergo self-modulation to form localized structures by balancing the nonlinearity with the dispersion. In presence of higher order nonlinearity, propagation of a high amplitude (∼5 times of background carrier wave) ion acoustic Peregrine soliton has been observed experimentally. The existence of such types of higher order wave has been reported in other dispersive media. These are considered to be the prototype of super rogue wave in deep water. In this work, experimental results on the evolution of super rogue wave in a double plasma device are presented and compared with the numerical solution of NLSE. (author)

  12. Waves, currents and sediment transport modelling at the Wave Hub site

    OpenAIRE

    Gonzalez-Santamaria, Raul

    2013-01-01

    Primary supervisory team: Qingping Zou and Shunqi Pan This research project uses an integrated modelling system to investigate the effects of a wave farm on nearshore sediment transport at the Wave Hub site. The Wave Hub project is a large scale demonstration site for the development of the operation of arrays of wave energy generation devices located at the southwest coast of the UK where multiple field measurements took place. Particular attention of this study was paid to th...

  13. 3D High Density mmWave Interconnects, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Nuvotronics has developed and optimized the PolyStrataTM process for the fabrication of intricate microwave and millimeter-wave devices. These devices have primarily...

  14. Integrated coherent matter wave circuits

    International Nuclear Information System (INIS)

    Ryu, C.; Boshier, M. G.

    2015-01-01

    An integrated coherent matter wave circuit is a single device, analogous to an integrated optical circuit, in which coherent de Broglie waves are created and then launched into waveguides where they can be switched, divided, recombined, and detected as they propagate. Applications of such circuits include guided atom interferometers, atomtronic circuits, and precisely controlled delivery of atoms. We report experiments demonstrating integrated circuits for guided coherent matter waves. The circuit elements are created with the painted potential technique, a form of time-averaged optical dipole potential in which a rapidly moving, tightly focused laser beam exerts forces on atoms through their electric polarizability. Moreover, the source of coherent matter waves is a Bose-Einstein condensate (BEC). Finally, we launch BECs into painted waveguides that guide them around bends and form switches, phase coherent beamsplitters, and closed circuits. These are the basic elements that are needed to engineer arbitrarily complex matter wave circuitry

  15. Multi-Wave Mixing Processes

    CERN Document Server

    Zhang, Yanpeng

    2009-01-01

    "Multi-Wave Mixing Processes - From Ultrafast Polarization Beats to Electromagnetically Induced Transparency" discusses the interactions of efficient multi-wave mixing (MWM) processes enhanced by atomic coherence in multilevel atomic systems. It covers topics in five major areas: attosecond and femtosecond polarization beats of four-wave mixing (FWM) processes; heterodyne detection of FWM, six-wave mixing (SWM) and eight-wave mixing (EWM) processes; Raman and Rayleigh enhanced polarization beats; coexistence and interactions of MWM processes via electromagnetically induced transparency(EIT); multi-dressing MWM processes. The book is intended for researchers, advanced undergraduate and graduate students in Nonlinear Optics. Dr. Yanpeng Zhang is a professor at the Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi'an Jiaotong University. Dr. Min Xiao is a professor of Physics at University of Arkansas, Fayetteville, U.S.A.

  16. Plasma waves

    National Research Council Canada - National Science Library

    Swanson, D. G

    1989-01-01

    ... Swanson, D.G. (Donald Gary), D a t e - Plasma waves. Bibliography: p. Includes index. 1. Plasma waves. QC718.5.W3S43 1989 ISBN 0-12-678955-X I. Title. 530.4'4 88-34388 Printed in the United Sta...

  17. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Brorsen, Michael; Frigaard, Peter

    Nærværende rapport beskriver numeriske beregninger af den hydrodynamiske interaktion mellem 5 flydere i bølgeenergianlægget Wave Star.......Nærværende rapport beskriver numeriske beregninger af den hydrodynamiske interaktion mellem 5 flydere i bølgeenergianlægget Wave Star....

  18. Sealing device

    Science.gov (United States)

    Garcia-Crespo, Andres Jose

    2013-12-10

    A sealing device for sealing a gap between a dovetail of a bucket assembly and a rotor wheel is disclosed. The sealing device includes a cover plate configured to cover the gap and a retention member protruding from the cover plate and configured to engage the dovetail. The sealing device provides a seal against the gap when the bucket assemply is subjected to a centrifugal force.

  19. Microfluidic Device

    Science.gov (United States)

    Tai, Yu-Chong (Inventor); Zheng, Siyang (Inventor); Lin, Jeffrey Chun-Hui (Inventor); Kasdan, Harvey L. (Inventor)

    2017-01-01

    Described herein are particular embodiments relating to a microfluidic device that may be utilized for cell sensing, counting, and/or sorting. Particular aspects relate to a microfabricated device that is capable of differentiating single cell types from dense cell populations. One particular embodiment relates a device and methods of using the same for sensing, counting, and/or sorting leukocytes from whole, undiluted blood samples.

  20. Gauging device

    International Nuclear Information System (INIS)

    Qurnell, F.D.; Patterson, C.B.

    1979-01-01

    A gauge supporting device for measuring say a square tube comprises a pair of rods or guides in tension between a pair of end members, the end members being spaced apart by a compression member or members. The tensioned guides provide planes of reference for measuring devices moved therealong on a carriage. The device is especially useful for making on site dimensional measurements of components, such as irradiated and therefore radioactive components, that cannot readily be transported to an inspection laboratory. (UK)

  1. Hydraulic Performance of Seawave Slot-Cone Generator Pilot Plant at Kvitsøy (Norway)

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Vicinanza, D.; Kofoed, Jens Peter

    This paper presents results on wave overtopping and loading on an innovative caisson breakwater for electricity production.......This paper presents results on wave overtopping and loading on an innovative caisson breakwater for electricity production....

  2. Wave energy : from demonstration to commercialization

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    The Wave Energy Centre is a non-profit organization dedicated to the development and marketing of ocean wave energy devices through technical and strategic support to companies and research and development institutions. WEC provides access to researchers to associated test infrastructures for testing and demonstration of wave energy structures. This presentation described the current status of wave energy. Public policies that support wave energy were also highlighted. Wave energy technology is currently in the demonstration phase, with several pilot plants and prototypes in service around the world. The first 2 offshore shoreline ocean wave current pilot plants were constructed in 2000. This presentation identified the 12 near or offshore pilot plants that were in operation by 2007. The pilot plants represent 5 basic different concepts with many different designs. The world's first commercial park was launched in 2007 in Portugal. The Pelamis wave farm uses three Pelamis P-750 machines with a capacity of 2.25 megawatts. figs.

  3. Fusion devices

    International Nuclear Information System (INIS)

    Fowler, T.K.

    1977-01-01

    Three types of thermonuclear fusion devices currently under development are reviewed for an electric utilities management audience. Overall design features of laser fusion, tokamak, and magnetic mirror type reactors are described and illustrated. Thrusts and trends in current research on these devices that promise to improve performance are briefly reviewed. Twenty photographs and drawings are included

  4. BRAKE DEVICE

    Science.gov (United States)

    O'Donnell, T.J.

    1959-03-10

    A brake device is described for utilization in connection with a control rod. The device comprises a pair of parallelogram link mechanisms, a control rod moveable rectilinearly therebetween in opposite directions, and shoes resiliently supported by the mechanism for frictional engagement with the control rod.

  5. Quasitravelling waves

    International Nuclear Information System (INIS)

    Beklaryan, Leva A

    2011-01-01

    A finite difference analogue of the wave equation with potential perturbation is investigated, which simulates the behaviour of an infinite rod under the action of an external longitudinal force field. For a homogeneous rod, describing solutions of travelling wave type is equivalent to describing the full space of classical solutions to an induced one-parameter family of functional differential equations of point type, with the characteristic of the travelling wave as parameter. For an inhomogeneous rod, the space of solutions of travelling wave type is trivial, and their 'proper' extension is defined as solutions of 'quasitravelling' wave type. By contrast to the case of a homogeneous rod, describing the solutions of quasitravelling wave type is equivalent to describing the quotient of the full space of impulsive solutions to an induced one-parameter family of point-type functional differential equations by an equivalence relation connected with the definition of solutions of quasitravelling wave type. Stability of stationary solutions is analyzed. Bibliography: 9 titles.

  6. PLASMA DEVICE

    Science.gov (United States)

    Gow, J.D.; Wilcox, J.M.

    1961-12-26

    A device is designed for producing and confining highenergy plasma from which neutrons are generated in copious quantities. A rotating sheath of electrons is established in a radial electric field and axial magnetic field produced within the device. The electron sheath serves as a strong ionizing medium to gas introdueed thereto and also functions as an extremely effective heating mechanism to the resulting plasma. In addition, improved confinement of the plasma is obtained by ring magnetic mirror fields produced at the ends of the device. Such ring mirror fields are defined by the magnetic field lines at the ends of the device diverging radially outward from the axis of the device and thereafter converging at spatial annular surfaces disposed concentrically thereabout. (AFC)

  7. Resonant Wave Energy Converters: Concept development

    International Nuclear Information System (INIS)

    Arena, Felice; Barbaro, Giuseppe; Fiamma, Vincenzo; Laface, Valentina; Malara, Giovanni; Romolo, Alessandra; Strati, Federica Mara

    2015-01-01

    The Resonant Wave Energy Converter (REWEC) is a device for converting sea wave energy to electrical energy. It belongs to the family of Oscillating Water Columns and is composed by an absorbing chamber connected to the open sea via a vertical duct. The paper gives a holistic view on the concept development of the device, starting from its implementation in the context of submerged breakwaters to the recently developed vertical breakwaters. [it

  8. Buoy-Rope-Drum Wave Power System

    Directory of Open Access Journals (Sweden)

    Linsen Zhu

    2013-01-01

    Full Text Available A buoy-rope-drum wave power system is a new type of floating oscillating buoy wave power device, which absorbs energy from waves by buoy-rope-drum device. Based on the linear deep water wave theory and pure resistive load, with cylinder buoy as an example, the research sets up the theoretical model of direct-drive buoy-rope-drum wave power efficiency and analyzes the influence of the mass and load of the system on its generating efficiency. It points out the two main categories of the efficient buoy-rope-drum wave power system: light thin type and resonance type, and optimal designs of their major parameters are carried out on the basis of the above theoretical model of generating efficiency.

  9. Submillimeter Wave Antenna With Slow Wave Feed Line

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Krozer, Viktor; Kotiranta, Mikko

    2009-01-01

    Submillimeter wave radiation, which is also referred to as terahertz radiation, has not been extensively explored until recently due to a lack of reliable components and devices in this frequency range. Current advances in technology have made it possible to explore this portion of the electromag...

  10. Extreme Wave Runup over the Steep Rocky Cliffs of Banneg Island, France

    Science.gov (United States)

    Ardhuin, F.; Dodet, G.; Leckler, F.; Suanez, S.; Filipot, J. F.

    2016-12-01

    Ocean waves are constantly shaping coastal morphology. When storm waves are combined with high water levels, the wave runup can reach unexpected elevations and become a threat for coastal populations, through dike overtopping, dune breaching or accelerated coastline erosion. Therefore, the wave runup has been largely investigated over the last decades for its key importance in coastal engineering and risk management. Although the strongly nonlinear nature of swash flows prevented theoreticians and modellers from accurately predicting its kinematics, numerous laboratory and field studies provided a means for establishing wave runup empirical formula, which are now commonly used in engineering practice. However, most of the field studies only concerned gently sloping sand beaches, and run-up formula have barely been validated against field observations in steep rocky environments, where data are still very sparse. This study presents water elevation data acquired with pressure sensors solidly fixed to the bedrock of Banneg Island, France, during winter 2013/14. Offshore wave parameters and water levels were also measured during this winter and recorded storm events with Hm0 up to 9 m in spring tide conditions, which caused flooding and boulder transports across the island. A methodology to infer R2% from the local pressure measurements was implemented. The 4-month time-series of run-up measurements at the top and at the bottom of subvertical cliff profiles (with slopes ranging from 20% to 30%) were compared with offshore wave parameters and revealed a strong dependence of R2% to the Hunt parameter (ξ.Hm0). Several period parameters based on the spectral moments were also tested to compute ξ and the best correlations were obtained with T(m0,-1). Finally, the exceptional run-up values (up to 8 m) measured at the cliff top during the major storms allowed to test the validity of existing run-up formula for a range of conditions that exceeds any other observations, to

  11. Solitary impulse wave run-up and overland flow

    International Nuclear Information System (INIS)

    Fuchs, H.

    2013-04-01

    Impulse waves are generated by landslides, rockfalls or avalanches impacting a reservoir or natural lake. These long waves generated by the impulse transferred to the water body in combination with the usually short propagation distance within a lake lead to a large damage potential due to wave run-up or dam overtopping. Damages are then caused by (1) direct wave load on structures, (2) driftwood and float impact and (3) their deposits after water retreat. Major historic events occurred at Lituya Bay, Alaska, in 1958, or at the Vaiont Reservoir, Italy, in 1963. Recent events were observed at Lake Chehalis, Canada, or Lake Lucerne, Switzerland, both in 2007, or at the Lower Grindelwald proglacial lake, Switzerland, in 2009. Whereas previous VAW research aimed at the generation phase of landslide-generated impulse waves with a special focus on the wave characteristics, the current research concentrates on the opposite wave-shore interaction. A particular focus is given to the transition point from the shore slope to the horizontal plane where the orbital wave motion is transformed into a shore-parallel flow. As most literature relates only to plain wave run-up on a linearly-inclined plane and the few studies focussing on wave-induced overland flow are case studies considering only a specific bathymetry, currently no general conclusions on wave-induced overland flow can be drawn. The present study therefore intends to fill in this gap by physical modeling. Testing involved a new test-setup including a piston-type wave maker to generate solitary waves, and a smooth impermeable PVC shore of height w = 0.25 m with a connected horizontal overland flow portion. By varying the shore slope tanβ = 1/1.5, 1/2.5 and 1/5.0, the still water depth h = 0.16 - 0.24 m, and the relative wave height H/h = 0.1 -0.7, a wide range of basic parameters was covered. Overland flow depths and front velocities were measured along the shore using Ultrasonic Distance Sensors. Further, flow

  12. Solitary impulse wave run-up and overland flow

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, H.

    2013-04-15

    Impulse waves are generated by landslides, rockfalls or avalanches impacting a reservoir or natural lake. These long waves generated by the impulse transferred to the water body in combination with the usually short propagation distance within a lake lead to a large damage potential due to wave run-up or dam overtopping. Damages are then caused by (1) direct wave load on structures, (2) driftwood and float impact and (3) their deposits after water retreat. Major historic events occurred at Lituya Bay, Alaska, in 1958, or at the Vaiont Reservoir, Italy, in 1963. Recent events were observed at Lake Chehalis, Canada, or Lake Lucerne, Switzerland, both in 2007, or at the Lower Grindelwald proglacial lake, Switzerland, in 2009. Whereas previous VAW research aimed at the generation phase of landslide-generated impulse waves with a special focus on the wave characteristics, the current research concentrates on the opposite wave-shore interaction. A particular focus is given to the transition point from the shore slope to the horizontal plane where the orbital wave motion is transformed into a shore-parallel flow. As most literature relates only to plain wave run-up on a linearly-inclined plane and the few studies focussing on wave-induced overland flow are case studies considering only a specific bathymetry, currently no general conclusions on wave-induced overland flow can be drawn. The present study therefore intends to fill in this gap by physical modeling. Testing involved a new test-setup including a piston-type wave maker to generate solitary waves, and a smooth impermeable PVC shore of height w = 0.25 m with a connected horizontal overland flow portion. By varying the shore slope tanβ = 1/1.5, 1/2.5 and 1/5.0, the still water depth h = 0.16 - 0.24 m, and the relative wave height H/h = 0.1 -0.7, a wide range of basic parameters was covered. Overland flow depths and front velocities were measured along the shore using Ultrasonic Distance Sensors. Further, flow

  13. Nanotube resonator devices

    Science.gov (United States)

    Jensen, Kenneth J; Zettl, Alexander K; Weldon, Jeffrey A

    2014-05-06

    A fully-functional radio receiver fabricated from a single nanotube is being disclosed. Simultaneously, a single nanotube can perform the functions of all major components of a radio: antenna, tunable band-pass filter, amplifier, and demodulator. A DC voltage source, as supplied by a battery, can power the radio. Using carrier waves in the commercially relevant 40-400 MHz range and both frequency and amplitude modulation techniques, successful music and voice reception has been demonstrated. Also disclosed are a radio transmitter and a mass sensor using a nanotube resonator device.

  14. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Frigaard, Peter

    Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Byggeri og Anlæg med bølgeenergianlæget Wave Star.......Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Byggeri og Anlæg med bølgeenergianlæget Wave Star....

  15. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Andersen, Thomas Lykke

    Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star.......Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star....

  16. Handbook of terahertz technologies devices and applications

    CERN Document Server

    Song, Ho-Jin

    2015-01-01

    Terahertz waves, which lie in the frequency range of 0.1-10 THz, have long been investigated in a few limited fields, such as astronomy, because of a lack of devices for their generation and detection. Several technical breakthroughs made over the last couple of decades now allow us to radiate and detect terahertz waves more easily, which has triggered the search for new uses of terahertz waves in many fields, such as bioscience, security, and information and communications technology. The book covers some of the technical breakthroughs in terms of device technologies. It discusses not only th

  17. Energy from the waves

    CERN Document Server

    Ross, D

    2012-01-01

    Revised and substantially expanded to include the latest developments in the field, the second edition of this popular book provides a concise, non-technical account of the historical background and current research and development in the field of wave energy and its planned utilisation. It explains in simple terms the technology involved and describes the new inventions, devices and discoveries which led wave energy to be regarded as a significant future source of alternative power. The author recounts the major events leading up to today's development; the roles played by the principal characters involved, inventors, engineers and politicians and the inevitable struggle which all pioneers must face. The book concludes by discussing the environmental implications, the political conflicts and the problems which lie ahead. Also included, is a useful glossary of terms and a selected bibliography of important technical reports and further sources of information.

  18. Sealing devices

    International Nuclear Information System (INIS)

    Coulson, R.A.

    1980-01-01

    A sealing device for minimising the leakage of toxic or radioactive contaminated environments through a biological shield along an opening through which a flexible component moves that penetrates the shield. The sealing device comprises an outer tubular member which extends over a length not less than the maximum longitudinal movement of the component along the opening. An inner sealing block is located intermediate the length of the component by connectors and is positioned in the bore of the outer tubular member to slide in the bore and effect a seal over the entire longitudinal movement of the component. The cross-section of the device may be circular and the block may be of polytetrafluoroethylene or of nylon impregnated with molybdenum or may be metallic. A number of the sealing devices may be combined into an assembly for a plurality of adjacent longitudinally movable components, each adapted to sustain a tensile load, providing the various drives of a master-slave manipulator. (author)

  19. Ferroelectric devices

    CERN Document Server

    Uchino, Kenji

    2009-01-01

    Updating its bestselling predecessor, Ferroelectric Devices, Second Edition assesses the last decade of developments-and setbacks-in the commercialization of ferroelectricity. Field pioneer and esteemed author Uchino provides insight into why this relatively nascent and interdisciplinary process has failed so far without a systematic accumulation of fundamental knowledge regarding materials and device development.Filling the informational void, this collection of information reviews state-of-the-art research and development trends reflecting nano and optical technologies, environmental regulat

  20. Wave energy converter effects on wave propagation: A sensitivity study in Monterey Bay, CA

    Science.gov (United States)

    Chang, G.; Jones, C. A.; Roberts, J.; Magalen, J.; Ruehl, K.; Chartrand, C.

    2014-12-01

    The development of renewable offshore energy in the United States is growing rapidly and wave energy is one of the largest resources currently being evaluated. The deployment of wave energy converter (WEC) arrays required to harness this resource could feasibly number in the hundreds of individual devices. The WEC arrays have the potential to alter nearshore wave propagation and circulation patterns and ecosystem processes. As the industry progresses from pilot- to commercial-scale it is important to understand and quantify the effects of WECs on the natural nearshore processes that support a local, healthy ecosystem. To help accelerate the realization of commercial-scale wave power, predictive modeling tools have been developed and utilized to evaluate the likelihood of environmental impact. At present, direct measurements of the effects of different types of WEC arrays on nearshore wave propagation are not available; therefore wave model simulations provide the groundwork for investigations of the sensitivity of model results to prescribed WEC characteristics over a range of anticipated wave conditions. The present study incorporates a modified version of an industry standard wave modeling tool, SWAN (Simulating WAves Nearshore), to simulate wave propagation through a hypothetical WEC array deployment site on the California coast. The modified SWAN, referred to as SNL-SWAN, incorporates device-specific WEC power take-off characteristics to more accurately evaluate a WEC device's effects on wave propagation. The primary objectives were to investigate the effects of a range of WEC devices and device and array characteristics (e.g., device spacing, number of WECs in an array) on nearshore wave propagation using SNL-SWAN model simulations. Results showed that significant wave height was most sensitive to variations in WEC device type and size and the number of WEC devices in an array. Locations in the lee centerline of the arrays in each modeled scenario showed the

  1. Efficient transformer for electromagnetic waves

    Science.gov (United States)

    Miller, R.B.

    A transformer structure for efficient transfer of electromagnetic energy from a transmission line to an unmatched load provides voltage multiplication and current division by a predetermined constant. Impedance levels are transformed by the square of that constant. The structure includes a wave splitter, connected to an input transmission device and to a plurality of output transmission devices. The output transmission devices are effectively connected in parallel to the input transmission device. The output transmission devices are effectively series connected to provide energy to a load. The transformer structure is particularly effective in increasing efficiency of energy transfer through an inverting convolute structure by capturing and transferring energy losses from the inverter to the load.

  2. Key features of wave energy.

    Science.gov (United States)

    Rainey, R C T

    2012-01-28

    For a weak point source or dipole, or a small body operating as either, we show that the power from a wave energy converter (WEC) is the product of the particle velocity in the waves, and the wave force (suitably defined). There is a thus a strong analogy with a wind or tidal turbine, where the power is the product of the fluid velocity through the turbine, and the force on it. As a first approximation, the cost of a structure is controlled by the force it has to carry, which governs its strength, and the distance it has to be carried, which governs its size. Thus, WECs are at a disadvantage compared with wind and tidal turbines because the fluid velocities are lower, and hence the forces are higher. On the other hand, the distances involved are lower. As with turbines, the implication is also that a WEC must make the most of its force-carrying ability-ideally, to carry its maximum force all the time, the '100% sweating WEC'. It must be able to limit the wave force on it in larger waves, ultimately becoming near-transparent to them in the survival condition-just like a turbine in extreme conditions, which can stop and feather its blades. A turbine of any force rating can achieve its maximum force in low wind speeds, if its diameter is sufficiently large. This is not possible with a simple monopole or dipole WEC, however, because of the 'nλ/2π' capture width limits. To achieve reasonable 'sweating' in typical wave climates, the force is limited to about 1 MN for a monopole device, or 2 MN for a dipole. The conclusion is that the future of wave energy is in devices that are not simple monopoles or dipoles, but multi-body devices or other shapes equivalent to arrays.

  3. Wave energy absorption by a floating air bag

    DEFF Research Database (Denmark)

    Kurniawan, Adi; Chaplin, John; Greaves, Deborah

    2017-01-01

    A floating air bag, ballasted in water, expands and contracts as it heaves under wave action. Connecting the bag to a secondary volume via a turbine transforms the bag into a device capable of generating useful energy from the waves. Small-scale measurements of the device reveal some interesting...

  4. Wave Generation Theory

    DEFF Research Database (Denmark)

    Frigaard, Peter; Høgedal, Michael; Christensen, Morten

    The intention of this manual is to provide some formulas and techniques which can be used for generating waves in hydraulic laboratories. Both long crested waves (2-D waves) and short crested waves (3-D waves) are considered.......The intention of this manual is to provide some formulas and techniques which can be used for generating waves in hydraulic laboratories. Both long crested waves (2-D waves) and short crested waves (3-D waves) are considered....

  5. Coupled wave sensor technology

    International Nuclear Information System (INIS)

    Maki, M.C.

    1988-01-01

    Buried line guided radar sensors have been used successfully for a number of years to provide perimeter security for high value resources. This paper introduces a new complementary sensor advancement at Computing Devices termed 'coupled wave device technology' (CWD). It provides many of the inherent advantages of leakey cable sensors, such as terrain-following and the ability to discriminate between humans and small animals. It also is able to provide a high or wide detection zone, and allows the sensor to be mounted aerially and adjacent to a wall or fence. Several alternative sensors have been developed which include a single-line sensor, a dual-line hybrid sensor that combines the elements of ported coax and CWD technology, and a rapid-deployment portable sensor for temporary or mobile applications. A description of the technology, the sensors, and their characteristics is provided

  6. 21 CFR 876.5990 - Extracorporeal shock wave lithotripter.

    Science.gov (United States)

    2010-04-01

    ..., control console, imaging/localization system, and patient table. Prior to treatment, the urinary stone is targeted using either an integral or stand-alone localization/imaging system. Shock waves are typically... shock wave lithotripter. (a) Identification. An extracorporeal shock wave lithotripter is a device that...

  7. Practical performances of MPC for wave energy converters

    DEFF Research Database (Denmark)

    Ferri, Francesco; Tetu, Amelie; Hals, J.

    2016-01-01

    Maximising the efficiency of Wave Energy Converter (WEC) is one of the important tasks toward the exploitation of the wave energy resource. Along with a proper design of the device, an important way to achieve better energy performances is to improve the wave-body interaction by applying an appro...

  8. Opportunities for shear energy scaling in bulk acoustic wave resonators

    NARCIS (Netherlands)

    Jose, Sumy; Hueting, Raymond Josephus Engelbart

    2014-01-01

    An important energy loss contribution in bulk acoustic wave resonators is formed by so-called shear waves, which are transversal waves that propagate vertically through the devices with a horizontal motion. In this work, we report for the first time scaling of the shear-confined spots, i.e., spots

  9. Wave conditions North of Brandsø island, DK

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Kofoed, Jens Peter

    This report was prepared under the ForskVE project WEPTOS#1 aiming at testing for the first time the wave energy device at sea. The results of this report are used to give an indication on the wave conditions at the selected location of testing and may also further be used for extrapolation of wave...

  10. Conversion Between Sine Wave and Square Wave Spatial Frequency Response of an Imaging System

    National Research Council Canada - National Science Library

    Nill, Norman B

    2001-01-01

    ...), is a primary image quality metric that is commonly measured with a sine wave target. The FBI certification program for commercial fingerprint capture devices, which MITRE actively supports, has an MTF requirement...

  11. Surface Acoustic Wave Monitor for Deposition and Analysis of Ultra-Thin Films

    Science.gov (United States)

    Hines, Jacqueline H. (Inventor)

    2015-01-01

    A surface acoustic wave (SAW) based thin film deposition monitor device and system for monitoring the deposition of ultra-thin films and nanomaterials and the analysis thereof is characterized by acoustic wave device embodiments that include differential delay line device designs, and which can optionally have integral reference devices fabricated on the same substrate as the sensing device, or on a separate device in thermal contact with the film monitoring/analysis device, in order to provide inherently temperature compensated measurements. These deposition monitor and analysis devices can include inherent temperature compensation, higher sensitivity to surface interactions than quartz crystal microbalance (QCM) devices, and the ability to operate at extreme temperatures.

  12. Waves in the seas

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J

    , steep nonsymmetric cnoidal waves, solitons and random waves. They have different properties too. Any wave form has a wave period (T), wave height (H) and speed (C) which depends on T. Still another type of waves are breaking waves near a coast...

  13. Zero-Power Radio Device.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2018-02-01

    This report describes an unpowered radio receiver capable of detecting and responding to weak signals transmit ted from comparatively long distances . This radio receiver offers key advantages over a short range zero - power radio receiver previously described in SAND2004 - 4610, A Zero - Power Radio Receiver . The device described here can be fabricated as an integrated circuit for use in portable wireless devices, as a wake - up circuit, or a s a stand - alone receiver operating in conjunction with identification decoders or other electroni cs. It builds on key sub - components developed at Sandia National Laboratories over many years. It uses surface acoustic wave (SAW) filter technology. It uses custom component design to enable the efficient use of small aperture antennas. This device uses a key component, the pyroelectric demodulator , covered by Sandia owned U.S. Patent 7397301, Pyroelectric Demodulating Detector [1] . This device is also described in Sandia owned U.S. Patent 97266446, Zero Power Receiver [2].

  14. Wave fronts of electromagnetic cyclotron harmonic waves

    International Nuclear Information System (INIS)

    Ohnuma, T.; Watanabe, T.

    1982-01-01

    In an inhomogeneous high-density magnetized plasma, the spatial properties of the wave fronts and ray trajectories of electromagnetic ordinary and extraordinary cyclotron harmonic waves are investigated. Those waves which are radiated from a local source are found to have wave fronts which are almost parallel to the magnetic field. Also, the reflective properties of the electromagnetic cyclotron harmonic waves are confirmed

  15. Wave Dragon

    DEFF Research Database (Denmark)

    Kramer, Morten; Frigaard, Peter

    På foranledning af Löwenmark F.R.I, er der udført numeriske beregninger af Wave Dragons (herefter WD) armes effektivitet for forskellige geometriske udformninger. 5 geometriske modeller, hvor WD's arme er forkortet/forlænget er undersøgt for 3 forskellige drejninger af armene. I alt er 15...

  16. Observation of Ion Acoustic Waves Excited by Drift Waves in a Weakly Magnetized Plasma

    International Nuclear Information System (INIS)

    Tsukabayashi, Isao; Sato, Sugiya; Nakamura, Yoshiharu

    2003-01-01

    Spontaneous fluctuations excited by drift waves are investigated experimentally in magnetic multi-pole plasma. The magnetic multi-pole has been widely used in DP devices and so on. It was observed that the high level of density fluctuations was generated by the drift instability near a magnetic multi-pole or a dipole magnet. The waves propagate to the middle plasma region forming the envelope train waves

  17. Medical Devices

    NARCIS (Netherlands)

    Verkerke, Gijsbertus Jacob; Mahieu, H.F.; Geertsema, A.A.; Hermann, I.F.; van Horn, J.R.; Hummel, J. Marjan; van Loon, J.P.; Mihaylov, D.; van der Plaats, A.; Schraffordt Koops, H.; Schutte, H.K.; Veth, R.P.H.; de Vries, M.P.; Rakhorst, G.; Shi, Donglu

    2004-01-01

    The development of new medical devices is a very time-consuming and costly process. Besides the time between the initial idea and the time that manufacturing and testing of prototypes takes place, the time needed for the development of production facilities, production of test series, marketing,

  18. Electrochemical device

    Science.gov (United States)

    Grimes, Patrick G.; Einstein, Harry; Bellows, Richard J.

    1988-01-12

    A tunnel protected electrochemical device features channels fluidically communicating between manifold, tunnels and cells. The channels are designed to provide the most efficient use of auxiliary power. The channels have a greater hydraulic pressure drop and electrical resistance than the manifold. This will provide a design with the optimum auxiliary energy requirements.

  19. Assistive Devices

    Science.gov (United States)

    If you have a disability or injury, you may use a number of assistive devices. These are tools, products or types of equipment that help you perform tasks and activities. They may help you move around, see, communicate, eat, or get ...

  20. Detection device

    Science.gov (United States)

    Smith, J.E.

    1981-02-27

    The present invention is directed to a detection device comprising: (1) an entrance chamber; (2) a central chamber; and (3) an exit chamber. The central chamber includes an ionizing gas, anode, and means for connecting the anode with an external power supply and pulse counter.

  1. Cooling device in thermonuclear device

    International Nuclear Information System (INIS)

    Honda, Tsutomu.

    1988-01-01

    Purpose: To prevent loss of cooling effect over the entire torus structure directly after accidental toubles in a cooling device of a thermonuclear device. Constitution: Coolant recycling means of a cooling device comprises two systems, which are alternately connected with in-flow pipeways and exit pipeways of adjacent modules. The modules are cooled by way of the in-flow pipeways and the exist pipeways connected to the respective modules by means of the coolant recycling means corresponding to the respective modules. So long as one of the coolant recycling means is kept operative, since every one other modules of the torus structure is still kept cooled, the heat generated from the module put therebetween, for which the coolant recycling is interrupted, is removed by means of heat conduction or radiation from the module for which the cooling is kept continued. No back-up emergency cooling system is required and it can provide high economic reliability. (Kamimura, M.)

  2. Traveling-Wave Membrane Photomixers

    Science.gov (United States)

    Wyss, R. A.; Martin, S. C.; Nakamura, B. J.; Neto, A.; Pasqualini, D.; Siegel, P. H.; Kadow, C.; Gossard, A. C.

    2001-01-01

    Traveling-wave photomixers have superior performance when compared with lumped area photomixers in the 1 to 3 THz frequency range. Their large active area and distributed gain mechanism assure high thermal damage threshold and elimination of the capacitive frequency roll-off. However, the losses experienced by the radio frequency wave traveling along the coplanar strips waveguide (due to underlying semi-infinite GaAs substrate) were a serious drawback. In this paper we present device designs and an experimental setup that make possible the realization of photomixers on membranes which eliminate the losses.

  3. Langmuir wave turbulence generated by electromagnetic waves in the laboratory and the ionosphere

    International Nuclear Information System (INIS)

    Lee, M.C.; Riddolls, R.J.; Moriarty, D.T.; Dalrymple, N.E.; Rowlands, M.J.

    1996-01-01

    The authors will present some recent results of the laboratory experiments at MIT, using a large plasma device known as the Versatile Toroidal Facility (VTF). These experiments are aimed at cross-checking the ionospheric plasma heating experiments at Arecibo, Puerto Rico using an HF heating facility (heater). The plasma phenomenon under investigation is the spectral characteristic of Langmuir wave turbulence produced by ordinary (o-mode) electromagnetic pump waves. The Langmuir waves excited by o-mode heaters waves at Arecibo have both a frequency-upshifted spectrum and a frequency-downshifted (viz., cascading) spectrum. While the cascading spectrum can be well explained in terms of the parametric decay instability (PDI), the authors have interpreted the frequency-upshifted Langmuir waves to be anti-Stokes Langmuir waves produced by a nonlinear scattering process as follows. Lower hybrid waves creates presumably by lightning-induced whistler waves can scatter nonlinearly the PDI-excited mother langmuir waves, yielding obliquely propagating langmuir waves with frequencies as the summation of the mother Langmuir wave frequencies and the lower hybrid wave frequencies. This suggested process has been confirmed in the laboratory experiments, that can reproduce the characteristic spectra of Langmuir wave turbulence observed in the Arecibo experiments

  4. Experiments and Numerical Simulations of Dike Erosion due to a Wave Impact

    Directory of Open Access Journals (Sweden)

    Stefania Evangelista

    2015-10-01

    Full Text Available Dike erosion is a crucial issue in coastal and fluvial flood risk management. These defense structures appear vulnerable to extreme hydrological events, whose potential occurrence risk seems to be recently increased due to climate change. Their design and reinforcement is, however, a complex task, and although numerical models are very powerful nowadays, real processes cannot be accurately predicted; therefore, physical models constitute a useful tool to investigate different features under controlled conditions. This paper presents some laboratory experimental results of erosion of a sand dike produced by the impact of a dam break wave. Experiments have been conducted in the Water Engineering Laboratory at the University of Cassino and Southern Lazio, Italy, in a rectangular channel: here, the sudden opening of a gate forming the reservoir generates the wave impacting the dike, made in turn of two different, almost uniform sands. The physical evidence proves that the erosion process is strongly unsteady and significantly different from a gradual overtopping and highlights the importance of apparent cohesion for the fine sand dike. The experimental results have also been compared against the ones obtained through the numerical integration of a two-phase model, which shows the reasonable predictive capability of the temporal free surface and dike profile evolution.

  5. WOCSDICE 1998: 22nd Workshop on Compound Semiconductor Devices and Integrated Circuits, May 24-27, 1998, Zeuthen, Germany

    National Research Council Canada - National Science Library

    1998-01-01

    .... Topics include material growth and characterization, recent developments in MESFETS, HEMTs, and HBTs, MMlC-Technology, Microwave and millimeter wave power devices, GaN- Devices, Mesoscopic devices...

  6. Pattern recognition with magnonic holographic memory device

    International Nuclear Information System (INIS)

    Kozhevnikov, A.; Dudko, G.; Filimonov, Y.; Gertz, F.; Khitun, A.

    2015-01-01

    In this work, we present experimental data demonstrating the possibility of using magnonic holographic devices for pattern recognition. The prototype eight-terminal device consists of a magnetic matrix with micro-antennas placed on the periphery of the matrix to excite and detect spin waves. The principle of operation is based on the effect of spin wave interference, which is similar to the operation of optical holographic devices. Input information is encoded in the phases of the spin waves generated on the edges of the magnonic matrix, while the output corresponds to the amplitude of the inductive voltage produced by the interfering spin waves on the other side of the matrix. The level of the output voltage depends on the combination of the input phases as well as on the internal structure of the magnonic matrix. Experimental data collected for several magnonic matrixes show the unique output signatures in which maxima and minima correspond to specific input phase patterns. Potentially, magnonic holographic devices may provide a higher storage density compare to optical counterparts due to a shorter wavelength and compatibility with conventional electronic devices. The challenges and shortcoming of the magnonic holographic devices are also discussed

  7. Impact of Wave Dragon on Wave Climate

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Tedd, James; Kramer, Morten

    This report is an advisory paper for use in determining the wave dragon effects on hydrography, by considering the effect on the wave climate in the region of a wave dragon. This is to be used in the impact assessment for the Wave Dragon pre-commercial demonstrator.......This report is an advisory paper for use in determining the wave dragon effects on hydrography, by considering the effect on the wave climate in the region of a wave dragon. This is to be used in the impact assessment for the Wave Dragon pre-commercial demonstrator....

  8. Gravitational waves

    CERN Document Server

    Ciufolini, I; Moschella, U; Fre, P

    2001-01-01

    Gravitational waves (GWs) are a hot topic and promise to play a central role in astrophysics, cosmology, and theoretical physics. Technological developments have led us to the brink of their direct observation, which could become a reality in the coming years. The direct observation of GWs will open an entirely new field: GW astronomy. This is expected to bring a revolution in our knowledge of the universe by allowing the observation of previously unseen phenomena, such as the coalescence of compact objects (neutron stars and black holes), the fall of stars into supermassive black holes, stellar core collapses, big-bang relics, and the new and unexpected.With a wide range of contributions by leading scientists in the field, Gravitational Waves covers topics such as the basics of GWs, various advanced topics, GW detectors, astrophysics of GW sources, numerical applications, and several recent theoretical developments. The material is written at a level suitable for postgraduate students entering the field.

  9. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Frigaard, Peter; Brorsen, Michael

    Nærværende rapport beskriver foreløbige hovedkonklusioner på modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star i perioden 13/9 2004 til 12/11 2004.......Nærværende rapport beskriver foreløbige hovedkonklusioner på modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star i perioden 13/9 2004 til 12/11 2004....

  10. Thermonuclear device

    International Nuclear Information System (INIS)

    Tezuka, Masaru.

    1993-01-01

    Protrusions and recesses are formed to a vacuum vessel and toroidal magnetic coils, and they are engaged. Since the vacuum vessel is generally supported firmly by a rack or the like by support legs, the toroidal magnetic field coils can be certainly supported against tumbling force. Then, there can be attained strong supports for the toroidal magnetic field coils, in addition to support by wedges on the side of inboard and support by share panels on the side of outboard, capable of withstanding great electromagnetic forces which may occur in large-scaled next-generation devices. That is, toroidal magnetic field coils excellent from a view point of deformation and stress can be obtained, to provide a thermonuclear device of higher reliability. (N.H.)

  11. Thermonuclear device

    International Nuclear Information System (INIS)

    Oosaki, Osamu; Masuda, Kenju.

    1980-01-01

    Purpose: To provide excellent electric properties and high reliability in a thermonuclear device by improving a current collecting board connected to a coil device. Constitution: A current collecting board element perforated with an opening for enserting a connecting terminal is sized to be inserted into a plating tank, and is surface treated in the plating tank. Only the current collecting board element preferably surface treated is picked up. A plurality of such current collecting board elements are connected and welded to form a large current collecting board. In this manner, the current collecting board having several m 2 to several ten order m 2 in area can be obtained as preferably surface treated at the connecting terminal hole. The current collecting board element can be determined in shape with the existing facility without increasing the size of a surface treating tank. (Kamimura, M.)

  12. Thermonuclear device

    International Nuclear Information System (INIS)

    Yagi, Yasuomi; Takahashi, Ken; Hashimoto, Hiroshi.

    1984-01-01

    Purpose: To improve the plasma confining performances by bringing the irregular magnetic fields nearly to zero and decreasing the absolute value of the irregular magnetic fields at every positions. Constitution: The winding direction of a plurality of coil elements, for instance, double pan cake coils of toroidal coils in a torus type or mirror type thermonuclear device are reversed to each other in their laminating direction, whereby the irregular magnetic fields due to the coil-stepped portions in each toroidal coils are brought nearly to zero. This enables to bring the average irregular magnetic fields as a whole in the thermonuclear device nearly to zero, as well as, decrease the absolute value of the irregular magnetic fields in each positions. Thus, the plasma confining performances can be improved. (Moriyama, K.)

  13. "Distinvar" device

    CERN Multimedia

    CERN PhotoLab

    1965-01-01

    The alignment of one of the accelerator magnets being checked by the AR Division survey group. A "distinvar" device, invented by the group, using calibrated invar wires stretched between the fixed survey pillar (on the left) and a fixed point on the magnet. In two days it is thus possible to measure the alignment of the 100 magnets with an accuracy better than 1/10.

  14. Latching device

    Science.gov (United States)

    Ulrich, G. W. (Inventor)

    1975-01-01

    A latching device is suited for use in establishing a substantially motionless connection between a stationary receiver and a movable latching mechanism. The latching mechanism includes a pivotally supported restraining hook continuously urged into a capturing relationship with the receiver, characterized by a spring-biased pawl having a plurality of aligned teeth. The teeth are seated in the surface of the throat of the hook and positionable into restraining engagement with a rigid restraining shoulder projected from the receiver.

  15. Shock Waves

    CERN Document Server

    Jiang, Z

    2005-01-01

    The International Symposium on Shock Waves (ISSW) is a well established series of conferences held every two years in a different location. A unique feature of the ISSW is the emphasis on bridging the gap between physicists and engineers working in fields as different as gas dynamics, fluid mechanics and materials sciences. The main results presented at these meetings constitute valuable proceedings that offer anyone working in this field an authoritative and comprehensive source of reference.

  16. CMS-Wave

    Science.gov (United States)

    2015-10-30

    Coastal Inlets Research Program CMS -Wave CMS -Wave is a two-dimensional spectral wind-wave generation and transformation model that employs a forward...marching, finite-difference method to solve the wave action conservation equation. Capabilities of CMS -Wave include wave shoaling, refraction... CMS -Wave can be used in either on a half- or full-plane mode, with primary waves propagating from the seaward boundary toward shore. It can

  17. Assimilation of Wave Imaging Radar Observations for Real-time Wave-by-Wave Forecasting

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, Alexandra [Oregon State Univ., Corvallis, OR (United States); Haller, Merrick [Oregon State Univ., Corvallis, OR (United States). School of Civil & Construction Engineering; Walker, David [SRI International, Menlo Park, CA (United States); Lynett, Pat [Univ. of Southern California, Los Angeles, CA (United States)

    2017-08-29

    This project addressed Topic 3: “Wave Measurement Instrumentation for Feed Forward Controls” under the FOA number DE-FOA-0000971. The overall goal of the program was to develop a phase-resolving wave forecasting technique for application to the active control of Wave Energy Conversion (WEC) devices. We have developed an approach that couples a wave imaging marine radar with a phase-resolving linear wave model for real-time wave field reconstruction and forward propagation of the wave field in space and time. The scope of the project was to develop and assess the performance of this novel forecasting system. Specific project goals were as follows: Develop and verify a fast, GPU-based (Graphical Processing Unit) wave propagation model suitable for phase-resolved computation of nearshore wave transformation over variable bathymetry; Compare the accuracy and speed of performance of the wave model against a deep water model in their ability to predict wave field transformation in the intermediate water depths (50 to 70 m) typical of planned WEC sites; Develop and implement a variational assimilation algorithm that can ingest wave imaging radar observations and estimate the time-varying wave conditions offshore of the domain of interest such that the observed wave field is best reconstructed throughout the domain and then use this to produce model forecasts for a given WEC location; Collect wave-resolving marine radar data, along with relevant in situ wave data, at a suitable wave energy test site, apply the algorithm to the field data, assess performance, and identify any necessary improvements; and Develop a production cost estimate that addresses the affordability of the wave forecasting technology and include in the Final Report. The developed forecasting algorithm (“Wavecast”) was evaluated for both speed and accuracy against a substantial synthetic dataset. Early in the project, performance tests definitively demonstrated that the system was capable of

  18. Up-Wave and Autoregressive Methods for Short-Term Wave Forecasting for an Oscillating Water Column

    OpenAIRE

    Paparella, Francesco; Monk, Kieran; Winands, Victor; Lopes, M.F.P.; Conley, Daniel; Ringwood, John

    2015-01-01

    The real-time control of wave energy converters (WECs) requires the prediction of the wave elevation at the location of the device in order to maximize the power extracted from the waves. One possibility is to predict the future wave elevation by combining its past history with the spatial information coming from a sensor which measures the free surface elevation up-wave of the WEC. As an application example, this paper focuses on the prediction of the wave elevation inside the chamber of the...

  19. Full wave simulations of lower hybrid wave propagation in tokamaks

    International Nuclear Information System (INIS)

    Wright, J. C.; Bonoli, P. T.; Phillips, C. K.; Valeo, E.; Harvey, R. W.

    2009-01-01

    Lower hybrid (LH) waves have the attractive property of damping strongly via electron Landau resonance on relatively fast tail electrons at (2.5-3)xv te , where v te ≡ (2T e /m e ) 1/2 is the electron thermal speed. Consequently these waves are well-suited to driving current in the plasma periphery where the electron temperature is lower, making LH current drive (LHCD) a promising technique for off-axis (r/a≥0.60) current profile control in reactor grade plasmas. Established techniques for computing wave propagation and absorption use WKB expansions with non-Maxwellian self-consistent distributions.In typical plasma conditions with electron densities of several 10 19 m -3 and toroidal magnetic fields strengths of 4 Telsa, the perpendicular wavelength is of the order of 1 mm and the parallel wavelength is of the order of 1 cm. Even in a relatively small device such as Alcator C-Mod with a minor radius of 22 cm, the number of wavelengths that must be resolved requires large amounts of computational resources for the full wave treatment. These requirements are met with a massively parallel version of the TORIC full wave code that has been adapted specifically for the simulation of LH waves [J. C. Wright, et al., Commun. Comput. Phys., 4, 545 (2008), J. C. Wright, et al., Phys. Plasmas 16 July (2009)]. This model accurately represents the effects of focusing and diffraction that occur in LH propagation. It is also coupled with a Fokker-Planck solver, CQL3D, to provide self-consistent distribution functions for the plasma dielectric as well as a synthetic hard X-ray (HXR) diagnostic for direct comparisons with experimental measurements of LH waves.The wave solutions from the TORIC-LH zero FLR model will be compared to the results from ray tracing from the GENRAY/CQL3D code via the synthetic HXR diagnostic and power deposition.

  20. Topology optimization of nonlinear optical devices

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard

    2011-01-01

    This paper considers the design of nonlinear photonic devices. The nonlinearity stems from a nonlinear material model with a permittivity that depends on the local time-averaged intensity of the electric field. A finite element model is developed for time-harmonic wave propagation and an incremen......This paper considers the design of nonlinear photonic devices. The nonlinearity stems from a nonlinear material model with a permittivity that depends on the local time-averaged intensity of the electric field. A finite element model is developed for time-harmonic wave propagation...... limiter. Here, air, a linear and a nonlinear material are distributed so that the wave transmission displays a strong sensitivity to the amplitude of the incoming wave....

  1. Optimization of bottom-hinged flap-type wave energy converter for a specific wave rose

    Science.gov (United States)

    Behzad, Hamed; Panahi, Roozbeh

    2017-06-01

    In this paper, we conducted a numerical analysis on the bottom-hinged flap-type Wave Energy Convertor (WEC). The basic model, implemented through the study using ANSYS-AQWA, has been validated by a three-dimensional physical model of a pitching vertical cylinder. Then, a systematic parametric assessment has been performed on stiffness, damping, and WEC direction against an incoming wave rose, resulting in an optimized flap-type WEC for a specific spot in the Persian Gulf. Here, stiffness is tuned to have a near-resonance condition considering the wave rose, while damping is modified to capture the highest energy for each device direction. Moreover, such sets of specifications have been checked at different directions to present the best combination of stiffness, damping, and device heading. It has been shown that for a real condition, including different wave heights, periods, and directions, it is very important to implement the methodology introduced here to guarantee device performance.

  2. Pressure suppression device

    International Nuclear Information System (INIS)

    Mizumachi, Wataru; Fukuda, Akira; Kitaguchi, Hidemi; Shimizu, Toshiaki.

    1976-01-01

    Object: To relieve and absorb impact wave vibrations caused by steam and non-condensed gases releasing into the pressure suppression chamber at the time of an accident. Structure: The reactor container is filled with inert gases. A safety valve attached main steam pipe is provided to permit the excessive steam to escape, the valve being communicated with the pressure suppression chamber through an exhaust pipe. In the pressure suppression chamber, a doughnut-like cylindrical outer wall is filled at its bottom with pool water to condense the high temperature vapor released through the exhaust pipe. A head portion of a vent tube which leads the exhaust pipe is positioned at the top, and a down comer and an exhaust vent tube are locked by means of steady rests. At the bottom is mounted a pressure adsorber device which adsorbs a pressure from the pool water. (Kamimura, M.)

  3. Focusing Leaky Waves: A Class of Electromagnetic Localized Waves with Complex Spectra

    Science.gov (United States)

    Fuscaldo, Walter; Comite, Davide; Boesso, Alessandro; Baccarelli, Paolo; Burghignoli, Paolo; Galli, Alessandro

    2018-05-01

    Localized waves, i.e., the wide class of limited-diffraction, limited-dispersion solutions to the wave equation are generally characterized by real wave numbers. We consider the role played by localized waves with generally complex "leaky" wave numbers. First, the impact of the imaginary part of the wave number (i.e., the leakage constant) on the diffractive (spatial broadening) features of monochromatic localized solutions (i.e., beams) is rigorously evaluated. Then general conditions are derived to show that only a restricted class of spectra (either real or complex) allows for generating a causal localized wave. It turns out that backward leaky waves fall into this category. On this ground, several criteria for the systematic design of wideband radiators, namely, periodic radial waveguides based on backward leaky waves, are established in the framework of leaky-wave theory. An effective design method is proposed to minimize the frequency dispersion of the proposed class of devices and the impact of the "leakage" on the dispersive (temporal broadening) features of polychromatic localized solutions (i.e., pulses) is accounted for. Numerical results corroborate the concept, clearly highlighting the advantages and limitations of the leaky-wave approach for the generation of localized pulses at millimeter-wave frequencies, where energy focusing is in high demand in modern applications.

  4. Damping device

    International Nuclear Information System (INIS)

    Banks, E.L. Jr.; Dowell, T.P.

    1976-01-01

    The description is given of a damper which includes a pair of telescopic components interconnected by relative linear movement one in relation to the other, by a screw and ball nut device, with a braking surface on one of the components, a brake engaging the braking surface, an inertia mass entrained by the other components, non-deformable and distinct brake actuating gear, independently mobile in relation to the other braking system and fixed and controlled by the inertia mass, positively to engage the braking surface. This damper is for retaining the parts of a nuclear power station so that can withstand earthquakes [fr

  5. Thermonuclear device

    International Nuclear Information System (INIS)

    Inoue, Toyokazu; Murata, Toru.

    1983-01-01

    Purpose: To shield superconducting coils for use in the generation of magnetic field against neutron irradiation thereby preventing tritium contamination. Constitution: The thermonuclear device comprises, in its inside, a vacuum container for containing plasmas, superconducting coils disposed to the outside of the vacuum container and neutron absorbers disposed between the super-conducting coils and the vacuum container. since neutrons issued from the plasma are absorbed by neutron absorbers and not irradiated to the superconducting coils, generation of tritium due to the reaction between 3 He in the liquid helium as the coolants for the super-conducting coils and the neutrons is prevented. (Aizawa, K.)

  6. Strainer device

    International Nuclear Information System (INIS)

    Mokuya, Kenji.

    1975-01-01

    Object: To provide a strainer device, which is adapted to facilitate flushing and is particularly suited for installation in the cooling system of a liquid metal cooled fast breeding reactor. Structure: A casing accommodating a strainer and a blind plate for the selection of a flow path is provided at a suitable portion of the duct line. The blind plate is adapted to be rotated by an opening and closing means consisting of a rod. bellows, shaft and so forth. At the time of flushing, the duct line is sealed by the blind plate. (Nakamura, S.)

  7. Experimental Study on the Langlee Wave Energy Converter

    DEFF Research Database (Denmark)

    Pecher, Arthur; Kofoed, Jens Peter; Weisz, A.

    This report presents the results of an experimental study of the wave energy converting abilities of the Langlee wave energy converter (WEC). It focused mainly on evaluating the power generating capabilities of the device, including investigations of the following issues: Scaling ratiosPTO loadingWave...... height and wave period dependencyOblique incoming waves and directional spreading of waves (3D waves)Damping platesMooring forces and fixed structure setupPitch, surge and heave motion During the study the model supplied by the client (Langlee Wave Power AS) has been heavily instrumented - up to 23...... different instruments was deployed to measure and record data. Tests were performed at scales of 1:30 and 1:20 based on the realized reference wave states....

  8. Experimental Study of the Weptos Wave Energy Converter

    DEFF Research Database (Denmark)

    Pecher, Arthur; Kofoed, Jens Peter; Larsen, Tommy

    2012-01-01

    This paper presents the power performance results of the experimental study of the WEPTOS wave energy converter (WEC). This novel device combines an established and efficient wave energy absorbing mechanism with an adjustable structure that can regulate the amount of incoming wave energy and reduce...... loads in extreme wave conditions. This A-shaped floating structure absorbs the energy in the waves through a multitude of rotors, the shape of which is based on the renowned Salter’s Duck. These rotors pivot around a common axle, one for each leg of the structure, to which the rotors transfer...... the absorbed wave energy and which is connected to a common power take off system (one for each leg). The study investigates the performance of the device in a large range of wave states and estimates the performance in terms of mechanical power available to the power take off system of the WEPTOS WEC for two...

  9. Dual output acoustic wave sensor for molecular identification

    International Nuclear Information System (INIS)

    Frye, G.C.; Martin, S.J.

    1991-01-01

    This patent describes an apparatus for detecting and identifying at least one unknown chemical species. It comprises: an acoustic wave device capable of generating, transmitting and receiving an acoustic wave, means for measuring the velocity of an acoustic wave travelling through the material; means for simultaneously measuring the attenuation of the acoustic wave traveling through the coating material; sampling means to contact the acoustic wave device to the unknown chemical species; means for determining the changes in both the attenuation and velocity values of the acoustic wave upon sorption of the unknown chemical species into the coating material; and means for correlating the magnitudes of the changes of velocity with respect to the changes of the attenuations of the acoustic wave; and means for comparing the values of the velocity and attenuation changes to known values of velocity and attenuation of known chemical species in order to identify the unknown sorbed chemical species

  10. Photometric device using optical fibers

    International Nuclear Information System (INIS)

    Boisde, Gilbert; Perez, J.-J.

    1981-02-01

    Remote measurements in radioactive environment are now possible with optical fibers. Measurement instruments developed by CEA are constitued of: - an optical probe (5 mm to 1 meter optical path length), - a photometric measurement device, - optical fiber links. 'TELEPHOT' is a photometric device for industrial installations. It is uses interferentiel filters for 2 to 5 simultaneous wave lengths. 'CRUDMETER' measures the muddiness of water. It can be equipped with a high sensitivity cell of 50 cm optical path length tested up to 250 bars. Coupling a double beam spectrophotometer to a remote optical probe, up to 1 meter optical path length, is carried out by means of an optical device using optical fibers links, eventually several hundred meter long. For these equipments special step index large core fibers, 1 to 1.5 mm in diameter, have been developed as well connectors. For industrial control and research these instruments offer new prospect thanks to optical fibers use [fr

  11. Scalable devices

    KAUST Repository

    Krüger, Jens J.

    2014-01-01

    In computer science in general and in particular the field of high performance computing and supercomputing the term scalable plays an important role. It indicates that a piece of hardware, a concept, an algorithm, or an entire system scales with the size of the problem, i.e., it can not only be used in a very specific setting but it\\'s applicable for a wide range of problems. From small scenarios to possibly very large settings. In this spirit, there exist a number of fixed areas of research on scalability. There are works on scalable algorithms, scalable architectures but what are scalable devices? In the context of this chapter, we are interested in a whole range of display devices, ranging from small scale hardware such as tablet computers, pads, smart-phones etc. up to large tiled display walls. What interests us mostly is not so much the hardware setup but mostly the visualization algorithms behind these display systems that scale from your average smart phone up to the largest gigapixel display walls.

  12. Thermonuclear device

    International Nuclear Information System (INIS)

    Honda, Takuro; Maki, Koichi.

    1997-01-01

    The present invention provides a thermonuclear device, in which integrity of a measuring device is kept, the reactor wall temperature and wear of armour materials are monitored accurately even under intense radiation rays, so that the flow rate of coolants and plasma power can be controlled by using the signals. Infrared rays generated from the surface of the armour materials disposed on a first wall are detected to measure the reactor wall temperature. Coolant flow rate and plasma power are controlled based on the obtained reactor wall temperature. In addition, infrared rays generated from the back of the armour materials are detected to obtain the surface temperature in order to avoid intense radiation rays from plasmas. The coolant flow rate and the plasma power are controlled based on the obtained temperature on the surface of the reactor thereby controlling the temperature of the first wall and the armour material to 300degC or lower in a case of the first wall made of stainless steel and 1000degC or lower in a case of the armour material made of graphite. (I.S.)

  13. Thermonuclear device

    International Nuclear Information System (INIS)

    Kuriyama, Masaaki; Yamamoto, Masahiro; Furuyama, Masayuki; Saito, Ryusei.

    1981-01-01

    Purpose: To enable the efficient and rapid cooling of a vacuum vessel by cooling with gas when the temperature of the vacuum vessel is higher than the boiling point of water and cooling with water when the temperature is lower than the boiling point of water. Constitution: A cooling pipe is provided through an insulating pipe on the outer periphery of a vacuum vessel. The cooling pipe communicates through a cooling gas valve and a coolant valve with a cooling gas supply device and a coolant supply device, and a heat exchanger is disposed at the pipe. When the vessel is higher than the boiling point of the coolant the coolant valve is closed and the cooling gas valve is opened and gas is supplied to cool the vessel. The gas is recoverd through a heat exchanger. On the other hand, when the temperature of vessel is lower than the boiling point of the coolant, the gas valve is closed, the coolant valve is opened, and the vessel is cooled with coolant. The vacuum vessel can be cooled for short time employing both the gas and the coolant together. (Yoshino, Y.)

  14. Thermonuclear device

    International Nuclear Information System (INIS)

    Takano, Hirohisa; Nakamoto, Kazunari; Hanai, Satoshi.

    1984-01-01

    Purpose: To provide coils of high mechanical strength for use at the center of a torus type thermonuclear device. Constitution: A plurality of copper plates having cooling holes and bolt holes and insulation paper sheets of the same shape are prepared. The copper plate is different from the insulation paper sheet only in that the position-phase angle of the opening portion is larger by 15 - 30 0 . The copper plates and the insulation paper sheets are alternately stacked by a required number of turns while displacing the angle, and then clamped by bolts to form a mechanically strong coil with no metallurgical joining. Further, since the insulation paper sheets are not present in the radial direction and only one insulation paper sheet is inserted for each turn in the direction of the coil height, the space occupied by the coil can be decreased. According to this invention, the magnetic flux density at the center of the device can be increased as compared with the conventional case to thereby apply a higher voltage on the side of plasmas. (Moriyama, K.)

  15. Irradiation device

    International Nuclear Information System (INIS)

    Suzuki, Toshimitsu.

    1989-01-01

    In an irradiation device for irradiating radiation rays such as electron beams to pharmaceuticals, etc., since the distribution of scanned electron rays was not monitored, the electron beam intensity could be determined only indirectly and irradiation reliability was not satisfactory. In view of the above, a plurality of monitor wires emitting secondary electrons are disposed in the scanning direction near a beam take-out window of a scanning duct, signals from the monitor wires are inputted into a display device such as a cathode ray tube, as well as signals from the monitor wires at the central portion are inputted into counting rate meters to measure the radiation dose as well. Since secondary electrons are emitted when electron beams pass through the monitor wires and the intensity thereof is in proportion with the intensity of incident electron beams, the distribution of the radiation dose can be monitored by measuring the intensity of the emitted secondary electrons. Further, uneven irradiation, etc. can also be monitored to make the radiation of irradiation rays reliable. (N.H.)

  16. A switchable spin-wave signal splitter for magnonic networks

    Science.gov (United States)

    Heussner, F.; Serga, A. A.; Brächer, T.; Hillebrands, B.; Pirro, P.

    2017-09-01

    The influence of an inhomogeneous magnetization distribution on the propagation of caustic-like spin-wave beams in unpatterned magnetic films has been investigated by utilizing micromagnetic simulations. Our study reveals a locally controllable and reconfigurable tractability of the beam directions. This feature is used to design a device combining split and switch functionalities for spin-wave signals on the micrometer scale. A coherent transmission of spin-wave signals through the device is verified. This attests the applicability in magnonic networks where the information is encoded in the phase of the spin waves.

  17. Application of Planar Broadband Slow-Wave Systems

    Directory of Open Access Journals (Sweden)

    Edvardas Metlevskis

    2012-04-01

    Full Text Available Different types of planar broadband slow-wave systems are used for designing microwave devices. The papers published by Lithuanian scientists analyze and investigate the models of helical and meander slow-wave systems. The article carefully examines the applications of meander slow-wave systems and presents the areas where similar systems, e.g. mobile devices, RFID, wireless technologies are used and reviewed nowadays. The paper also focuses on the examples of the papers discussing antennas, filters and couplers that contain designed and fabricated meander slow-wave systems.Article in Lithuanian

  18. Demonstration of a robust magnonic spin wave interferometer.

    Science.gov (United States)

    Kanazawa, Naoki; Goto, Taichi; Sekiguchi, Koji; Granovsky, Alexander B; Ross, Caroline A; Takagi, Hiroyuki; Nakamura, Yuichi; Inoue, Mitsuteru

    2016-07-22

    Magnonics is an emerging field dealing with ultralow power consumption logic circuits, in which the flow of spin waves, rather than electric charges, transmits and processes information. Waves, including spin waves, excel at encoding information via their phase using interference. This enables a number of inputs to be processed in one device, which offers the promise of multi-input multi-output logic gates. To realize such an integrated device, it is essential to demonstrate spin wave interferometers using spatially isotropic spin waves with high operational stability. However, spin wave reflection at the waveguide edge has previously limited the stability of interfering waves, precluding the use of isotropic spin waves, i.e., forward volume waves. Here, a spin wave absorber is demonstrated comprising a yttrium iron garnet waveguide partially covered by gold. This device is shown experimentally to be a robust spin wave interferometer using the forward volume mode, with a large ON/OFF isolation value of 13.7 dB even in magnetic fields over 30 Oe.

  19. Practical microwave electron devices

    CERN Document Server

    Meurant, Gerard

    2013-01-01

    Practical Microwave Electron Devices provides an understanding of microwave electron devices and their applications. All areas of microwave electron devices are covered. These include microwave solid-state devices, including popular microwave transistors and both passive and active diodes; quantum electron devices; thermionic devices (including relativistic thermionic devices); and ferrimagnetic electron devices. The design of each of these devices is discussed as well as their applications, including oscillation, amplification, switching, modulation, demodulation, and parametric interactions.

  20. Ultrasonic viewing device

    International Nuclear Information System (INIS)

    Ito, Juro.

    1979-01-01

    Purpose: To improve the safety of reactor operation by enabling to detect the states and positions of fuel assemblies over a wide range with a set of ultrasonic viewing device comprising a rotatable ultrasonic transmitter-receiver and a reflector mounted with an adjustable angle. Constitution: A driving portion for a ultrasonic viewing device is provided to a rotary plug closing the opening of a reactor vessel and a guide pipe suspending below the coolant level is provided to the driving portion. An ultrasonic transmitter-receiver is provided at the end of the holder tube in the guide pipe. A reflector is provided at the upper position of the reactor core so as to correspond to the ultrasonic transmitter-receiver. The ultrasonic transmitter-receiver, positioned by the driving portion, performs horizontal movement for scanning the entire surface of the top of the reactor core, as well as vertical movement covering the gap between the upper mechanism on the reactor and the reactor core, whereby the confirmation for the separation of the control rod and the detection for the states of the reactor core can be conducted by the reflection waves from the reflector. (Moriyama, K.)

  1. Diamond: a material for acoustic devices

    OpenAIRE

    MORTET, Vincent; WILLIAMS, Oliver; HAENEN, Ken

    2008-01-01

    Diamond has been foreseen to replace silicon for high power, high frequency electronic applications or for devices that operates in harsh environments. However, diamond electronic devices are still in the laboratory stage due to the lack of large substrates and the complexity of diamond doping. On another hand, surface acoustic wave filters based on diamond are commercially available. Diamond is especially suited for acoustic applications because of its exceptional mechanical properties. The ...

  2. Thermonuclear device

    International Nuclear Information System (INIS)

    Furuyama, Masayuki.

    1979-01-01

    Purpose: To provide the subject device wherein a conductive short-circuiting ring is installed in the vicinity of the bonded part of bellows and thick portion of vacuum vessel in the small circumferential direction of torus, thereby to reduce the electromagnetic force generated at the bellows. Constitution: A conductive short-circuiting ring is provided in the vicinity of the connected part of a thick portion and bellows portion. By this organization, a saddle type current generated at the thick portion by a vertical magnetic field flows through the short-circuiting ring because the resistance at a part where the short-circuiting ring is provided is reduced, and the current flowing through the bellows is remarkably reduced. For this reason, the electromagnetic force generated at the bellows is reduced thereby to prevent the bellows from being destroyed by the electromagnetic force. (Yoshihara, H.)

  3. Electrophoresis device

    Science.gov (United States)

    Rhodes, P. H.; Snyder, R. S. (Inventor)

    1982-01-01

    A device for separating cellular particles of a sample substance into fractionated streams of different cellular species includes a casing having a distribution chamber, a separation chamber, and a collection chamber. The electrode chambers are separated from the separation chamber interior by means of passages such that flow variations and membrane variations around the slotted portion of the electrode chamber do not enduce flow perturbations into the laminar buffer curtain flowing in the separation chamber. The cellular particles of the sample are separated under the influence of the electrical field and the separation chamber into streams of different cellular species. The streams of separated cells enter a partition array in the collection chamber where they are fractionated and collected.

  4. Thermonuclear device

    International Nuclear Information System (INIS)

    Suzuki, Shohei

    1988-01-01

    Purpose: To obtain high voltage withstanding current introduction terminals not suffering from the effects of the reduction in the creeping voltage withstanding property by the application of magnetic fields. Constitution: This invention concerns a current introduction terminal for supplying electric current to coils for use in a thermonuclear device, etc. The conductor of the current introduction terminal on the side of vacuum is completely covered with solid insulator. This can eliminate the portion of securing the creeping withstanding voltage. The voltage withstanding characteristics of the solid insulator covering the portion of the conductor on the side of vacuum has a constant value irrespective of the atmosphere or the absence or presence of magnetic fields. Accordingly, the voltage withstanding characteristics of the current introduction terminal on the side of vacuum are determined by the property of the solid insulator, which is not reduced by the application of magnetic fields. (Ikeda, J.)

  5. General method for designing wave shape transformers.

    Science.gov (United States)

    Ma, Hua; Qu, Shaobo; Xu, Zhuo; Wang, Jiafu

    2008-12-22

    An effective method for designing wave shape transformers (WSTs) is investigated by adopting the coordinate transformation theory. Following this method, the devices employed to transform electromagnetic (EM) wave fronts from one style with arbitrary shape and size to another style, can be designed. To verify this method, three examples in 2D spaces are also presented. Compared with the methods proposed in other literatures, this method offers the general procedure in designing WSTs, and thus is of great importance for the potential and practical applications possessed by such kinds of devices.

  6. Resonances and surface waves in bounded plasmas

    International Nuclear Information System (INIS)

    Bowers, K.J.; Qui, D.W.; Smith, H.B.; Birdsall, C.K.

    1999-01-01

    Surface waves provide a promising means of creating large, area plasmas. These waves can uniformly distribute the excitation energy and while presenting a small resistance and zero reactance to the driving source. Experimentally and in the simulations, the electron temperature is low (like 1--3 eV) as is the plasma potential (like 10 Te). The use of surface waves experimentally, and now industrially, to sustain large area plasma sources with device size is comparable to free space wavelength have motivated the authors to refine the theories of [1] and [2] to be fully electromagnetic. The wave dispersion predicted by the electromagnetic theory differs from the predictions of the prior theories and the results illuminate limitations of the electrostatic model. The use of surface waves have also motivated them to explore the mechanisms by which surface waves heat the plasma. In the 1d electrostatic simulations high velocity electron bunches are formed in the sheaths and are alternatively accelerated from each sheath into the bulk plasma each RF cycle. They speculate similar mechanisms provide the ionization in surface wave discharges. They also see in these simulations the plasma makes an abrupt transition from capacitively coupled to resistively coupled and the series resonance locks onto the drive frequency; these abrupt transitions resemble mode-jumping seen experimentally in large area sources. Furthermore, the density profile of the plasma tracks the drive frequency while in the resonant mode giving a new mechanism by which the plasma parameters can be controlled. They are currently investigating the effect of the driving electrode shape has on these resonances and conducting 2d simulations of a large area surface wave source to explore the ignition of surface wave devices and how the plasma fills in the device

  7. Safety device of thermonuclear device

    International Nuclear Information System (INIS)

    Aoki, Isao; Ueda, Shuzo; Seki, Yasushi; Sakurai, Akiko; Kasahara, Fumio; Obara, Atsushi; Yamauchi, Michinori.

    1997-01-01

    The present invention provides a safety device against an event of intrusion of coolants in a vacuum vessel. Namely, a coolant supply system comprises cooling tubes for supplying coolants to main reactor structure components including a vacuum vessel. A detection means detects leakage of coolants in the vacuum vessel. A coolant supply control means controls the supply of coolants to the main reactor structural components based on the leakage detection signals of the detection means. A stagnated material discharging means discharges stagnated materials in the main reactor structural components caused by the leakage of coolants. The leakage of coolants (for example, water) in the vacuum vessel can thus be detected by the water detection device in the vacuum vessel. A control value of a coolant supply means is closed by the leakage detection signals. The supply of coolants to the main reactor structural components is restricted to suppress the leakage. The stagnated materials are discharged to a tank by way of a water draining valve. (I.S.)

  8. Perspectives of using spin waves for computing and signal processing

    Energy Technology Data Exchange (ETDEWEB)

    Csaba, György, E-mail: gcsaba@gmail.com [Center for Nano Science and Technology, University of Notre Dame (United States); Faculty for Information Technology and Bionics, Pázmány Péter Catholic University (Hungary); Papp, Ádám [Center for Nano Science and Technology, University of Notre Dame (United States); Faculty for Information Technology and Bionics, Pázmány Péter Catholic University (Hungary); Porod, Wolfgang [Center for Nano Science and Technology, University of Notre Dame (United States)

    2017-05-03

    Highlights: • We give an overview of spin wave-based computing with emphasis on non-Boolean signal processors. • Spin waves can combine the best of electronics and photonics and do it in an on-chip and integrable way. • Copying successful approaches from microelectronics may not be the best way toward spin-wave based computing. • Practical devices can be constructed by minimizing the number of required magneto-electric interconnections. - Abstract: Almost all the world's information is processed and transmitted by either electric currents or photons. Now they may get a serious contender: spin-wave-based devices may just perform some information-processing tasks in a lot more efficient and practical way. In this article, we give an engineering perspective of the potential of spin-wave-based devices. After reviewing various flavors for spin-wave-based processing devices, we argue that the niche for spin-wave-based devices is low-power, compact and high-speed signal-processing devices, where most traditional electronics show poor performance.

  9. Efficient Wave Energy Amplification with Wave Reflectors

    DEFF Research Database (Denmark)

    Kramer, Morten Mejlhede; Frigaard, Peter Bak

    2002-01-01

    Wave Energy Converters (WEC's) extract wave energy from a limited area, often a single point or line even though the wave energy is generally spread out along the wave crest. By the use of wave reflectors (reflecting walls) the wave energy is effectively focused and increased to approximately 130......-140%. In the paper a procedure for calculating the efficiency and optimizing the geometry of wave reflectors are described, this by use of a 3D boundary element method. The calculations are verified by laboratory experiments and a very good agreement is found. The paper gives estimates of possible power benifit...... for different geometries of the wave reflectors and optimal geometrical design parameters are specified. On this basis inventors of WEC's can evaluate whether a specific WEC possible could benefit from wave reflectors....

  10. Modeling High Frequency Semiconductor Devices Using Maxwell's Equations

    National Research Council Canada - National Science Library

    El-Ghazaly, Samier

    1999-01-01

    .... In this research, we first replaced the conventional semiconductor device models, which are based on Poisson's Equation as a semiconductor model, with a new one that uses the full-wave electro...

  11. Protective, Modular Wave Power Generation System

    Energy Technology Data Exchange (ETDEWEB)

    Vvedensky, Jane M.; Park, Robert Y.

    2012-11-27

    The concept of small wave energy conversion modules that can be built into large, scalable arrays, in the same vein as solar panels, has been developed. This innovation lends itself to an organic business and development model, and enables the use of large-run manufacturing technology to reduce system costs. The first prototype module has been built to full-scale, and tested in a laboratory wave channel. The device has been shown to generate electricity and dissipate wave energy. Improvements need to be made to the electrical generator and a demonstration of an array of modules should be made in natural conditions.

  12. Waves and Tsunami Project

    Science.gov (United States)

    Frashure, K. M.; Chen, R. F.; Stephen, R. A.; Bolmer, T.; Lavin, M.; Strohschneider, D.; Maichle, R.; Micozzi, N.; Cramer, C.

    2007-01-01

    Demonstrating wave processes quantitatively in the classroom using standard classroom tools (such as Slinkys and wave tanks) can be difficult. For example, waves often travel too fast for students to actually measure amplitude or wavelength. Also, when teaching propagating waves, reflections from the ends set up standing waves, which can confuse…

  13. Image processing to optimize wave energy converters

    Science.gov (United States)

    Bailey, Kyle Marc-Anthony

    The world is turning to renewable energies as a means of ensuring the planet's future and well-being. There have been a few attempts in the past to utilize wave power as a means of generating electricity through the use of Wave Energy Converters (WEC), but only recently are they becoming a focal point in the renewable energy field. Over the past few years there has been a global drive to advance the efficiency of WEC. Placing a mechanical device either onshore or offshore that captures the energy within ocean surface waves to drive a mechanical device is how wave power is produced. This paper seeks to provide a novel and innovative way to estimate ocean wave frequency through the use of image processing. This will be achieved by applying a complex modulated lapped orthogonal transform filter bank to satellite images of ocean waves. The complex modulated lapped orthogonal transform filterbank provides an equal subband decomposition of the Nyquist bounded discrete time Fourier Transform spectrum. The maximum energy of the 2D complex modulated lapped transform subband is used to determine the horizontal and vertical frequency, which subsequently can be used to determine the wave frequency in the direction of the WEC by a simple trigonometric scaling. The robustness of the proposed method is provided by the applications to simulated and real satellite images where the frequency is known.

  14. Wavelet library for constrained devices

    Science.gov (United States)

    Ehlers, Johan Hendrik; Jassim, Sabah A.

    2007-04-01

    The wavelet transform is a powerful tool for image and video processing, useful in a range of applications. This paper is concerned with the efficiency of a certain fast-wavelet-transform (FWT) implementation and several wavelet filters, more suitable for constrained devices. Such constraints are typically found on mobile (cell) phones or personal digital assistants (PDA). These constraints can be a combination of; limited memory, slow floating point operations (compared to integer operations, most often as a result of no hardware support) and limited local storage. Yet these devices are burdened with demanding tasks such as processing a live video or audio signal through on-board capturing sensors. In this paper we present a new wavelet software library, HeatWave, that can be used efficiently for image/video processing/analysis tasks on mobile phones and PDA's. We will demonstrate that HeatWave is suitable for realtime applications with fine control and range to suit transform demands. We shall present experimental results to substantiate these claims. Finally this library is intended to be of real use and applied, hence we considered several well known and common embedded operating system platform differences; such as a lack of common routines or functions, stack limitations, etc. This makes HeatWave suitable for a range of applications and research projects.

  15. Systematic design of acoustic devices by topology optimization

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard; Sigmund, Ole

    2005-01-01

    We present a method to design acoustic devices with topology optimization. The general algorithm is exemplified by the design of a reflection chamber that minimizes the transmission of acoustic waves in a specified frequency range.......We present a method to design acoustic devices with topology optimization. The general algorithm is exemplified by the design of a reflection chamber that minimizes the transmission of acoustic waves in a specified frequency range....

  16. The Physics of Alfvén Waves

    CERN Document Server

    Cramer, Neil F

    2011-01-01

    Low-frequency wave modes of magnetized inhomogeneous plasmas have been subject to intense study in the last decade because they play important roles in the transport of energy in the plasmas. The "Alfvén wave heating" scheme has been investigated as a supplementary heating scheme for fusion plasma devices, and it has been invoked as a model of the heating of the solar and stellar coronae.This book covers the latest research into the properties and applications of low-frequency wave modes in magnetized plasmas, the Alfvén waves and magneto-acoustic waves, in the context of laborat

  17. Thermonuclear device

    International Nuclear Information System (INIS)

    Suzuki, Shohei.

    1980-01-01

    Purpose: To improve the plasma confining efficiency in a thermonuclear device having magnet coils using super-conducting wires by decreasing the uneven magnetic field resulted from current supply terminals and wirings. Constitution: Current introduction terminals of magnet coils using superconducting wires are short circuitted with a superconducting short circuit wire. Upon supplying current to the coils, the resistance of the coils is rendered superconductive and the resistance of the short circuit wire is rendered normally conductive heated by a heater and the switch is closed. In this case, most parts of the current are flown through the resistance of the coils and the switch is opened when the current arrives at a predetermined value to render the resistance of the short circuit wire superconductive. Then, the current transfers from the thyristor power source to the resistance of the short circuit wire, whereby the resistance of the coils and that of the short circuit wire from a permanent current loop. In this conditions, since current flows through the short circuit wire and the coils and not to the current introduction terminals, no uniform magnetic field is generated. (Kawakami, Y.)

  18. Reluctance device

    International Nuclear Information System (INIS)

    Claridge, A.N.; Smith, A.J.

    1983-01-01

    A reluctance device comprises two or more phases, each of which has a rotor mounted for rotation within a tubular member and an annular stator positioned externally of the tubular member. The rotor and the internal surface of the tubular member are each provided with aligned, axially spaced apart annular arrays of teeth, the teeth on the rotor confronting those on the tubular member in radially spaced apart relationship. The stator encloses a coil which, when electrically energised, creates a plurality of magnetic flux paths each of which extends radially between the rotor and stator via the confronting teeth and the tubular member, and axially along both the rotor and the portion of the stator located radially outwardly of the coil. The portion of the tubular member intermediate the teeth thereon is provided with a non-magnetic insert in order to resist the axial passage of magnetic flux therethrough. In one of the claims, the tubular member comprises a portion of a nuclear reactor which is adapted to contain a reactor control rod, the rotor constituting a portion of the drive mechanism for the control rod contained in operation within the tubular member. (author)

  19. Protection device for a thermonuclear device

    International Nuclear Information System (INIS)

    Kawashima, Shuichi.

    1986-01-01

    Purpose: To exactly detect the void coefficients of coolants even under high magnetic fields thereby detect the overheat of a thermonuclear device at an early stage. Constitution: The protecting device of this invention comprises a laser beam generation device, a laser beam detection device and an accident detection device. The laser generation device always generates laser beams, which are permeated through coolants and detected by the laser beam detection device, the optical amount of which is transmitted to the accident detection device. The accident detection device judges the excess or insufficiency of the detected optical amount with respect to the optical amount of the laser beams under the stationary state as a reference and issues an accident signal. Since only the optical cables that do not undergo the effect of the magnetic fields are exposed to high magnetic fields in the protection device of this invention, a high reliability can be maintained. (Kamimura, M.)

  20. Analysis and optimization of Love wave liquid sensors.

    Science.gov (United States)

    Jakoby, B; Vellekoop, M J

    1998-01-01

    Love wave sensors are highly sensitive microacoustic devices, which are well suited for liquid sensing applications thanks to the shear polarization of the wave. The sensing mechanism thereby relies on the mechanical (or acoustic) interaction of the device with the liquid. The successful utilization of Love wave devices for this purpose requires proper shielding to avoid unwanted electric interaction of the liquid with the wave and the transducers. In this work we describe the effects of this electric interaction and the proper design of a shield to prevent it. We present analysis methods, which illustrate the impact of the interaction and which help to obtain an optimized design of the proposed shield. We also present experimental results for devices that have been fabricated according to these design rules.

  1. Finite Amplitude Ocean Waves

    Indian Academy of Sciences (India)

    IAS Admin

    wavelength, they are called shallow water waves. In the ... Deep and intermediate water waves are dispersive as the velocity of these depends on wavelength. This is not the ..... generation processes, the finite amplitude wave theories are very ...

  2. Metamaterial mirrors in optoelectronic devices

    KAUST Repository

    Esfandyarpour, Majid

    2014-06-22

    The phase reversal that occurs when light is reflected from a metallic mirror produces a standing wave with reduced intensity near the reflective surface. This effect is highly undesirable in optoelectronic devices that use metal films as both electrical contacts and optical mirrors, because it dictates a minimum spacing between the metal and the underlying active semiconductor layers, therefore posing a fundamental limit to the overall thickness of the device. Here, we show that this challenge can be circumvented by using a metamaterial mirror whose reflection phase is tunable from that of a perfect electric mirror († = €) to that of a perfect magnetic mirror († = 0). This tunability in reflection phase can also be exploited to optimize the standing wave profile in planar devices to maximize light-matter interaction. Specifically, we show that light absorption and photocurrent generation in a sub-100 nm active semiconductor layer of a model solar cell can be enhanced by ∼20% over a broad spectral band. © 2014 Macmillan Publishers Limited.

  3. Metamaterial mirrors in optoelectronic devices

    KAUST Repository

    Esfandyarpour, Majid; Garnett, Erik C.; Cui, Yi; McGehee, Michael D.; Brongersma, Mark L.

    2014-01-01

    The phase reversal that occurs when light is reflected from a metallic mirror produces a standing wave with reduced intensity near the reflective surface. This effect is highly undesirable in optoelectronic devices that use metal films as both electrical contacts and optical mirrors, because it dictates a minimum spacing between the metal and the underlying active semiconductor layers, therefore posing a fundamental limit to the overall thickness of the device. Here, we show that this challenge can be circumvented by using a metamaterial mirror whose reflection phase is tunable from that of a perfect electric mirror († = €) to that of a perfect magnetic mirror († = 0). This tunability in reflection phase can also be exploited to optimize the standing wave profile in planar devices to maximize light-matter interaction. Specifically, we show that light absorption and photocurrent generation in a sub-100 nm active semiconductor layer of a model solar cell can be enhanced by ∼20% over a broad spectral band. © 2014 Macmillan Publishers Limited.

  4. Hydraulic Evaluation of the Crest Wing Wave Energy Converter

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Antonishen, Michael Patrick

    This report presents the results of an experimental study of the wave energy converting abilities of the Crest Wing wave energy converter (WEC). The Crest Wing is a WEC that uses its movement in matching the shape of an oncoming wave to generate power. Model tests have been performed using a scale...... model (length scale 1:30), provided by WaveEnergyFyn, in regular and irregular wave states that can be found in Assessment of Wave Energy Devices. Best Practice as used in Denmark (Frigaard et al., 2008). The tests were carried out at Dept. of Civil Engineering, Aalborg (Frigaard et al., 2008......). The tests were carried out at Dept. of Civil Engineering, Aalborg University (AAU) in the 3D deep water wave tank. The displacement and force applied to a power take off system, provided by WaveEnergyFyn, were measured and used to calculate total power take off....

  5. New Vacuum Electronic Devices for Radar

    Directory of Open Access Journals (Sweden)

    Hu Yinfu

    2016-08-01

    Full Text Available Vacuum Electronic Devices (VEDs which are considered as the heart of a radar system, play an important role in their development. VEDs and radar systems supplement and promote each other. Some new trends in VEDs have been observed with advancements in the simulation tools for designing VEDs, new materials, new fabrication techniques. Recently, the performance of VEDs has greatly improved. In addition, new devices have been invented, which have laid the foundation for the developments of radar detection technology. This study introduces the recent development trends and research results of VEDs from microwave and millimeter wave devices and power modules, integrated VEDs, terahertz VEDs, and high power VEDs.

  6. Pathway to a compact SASE FEL device

    Science.gov (United States)

    Dattoli, G.; Di Palma, E.; Petrillo, V.; Rau, Julietta V.; Sabia, E.; Spassovsky, I.; Biedron, S. G.; Einstein, J.; Milton, S. V.

    2015-10-01

    Newly developed high peak power lasers have opened the possibilities of driving coherent light sources operating with laser plasma accelerated beams and wave undulators. We speculate on the combination of these two concepts and show that the merging of the underlying technologies could lead to new and interesting possibilities to achieve truly compact, coherent radiator devices.

  7. Design of acoustic devices by topology optimization

    DEFF Research Database (Denmark)

    Sigmund, Ole; Jensen, Jakob Søndergaard

    2003-01-01

    The goal of this study is to design and optimize structures and devices that are subjected to acoustic waves. Examples are acoustic lenses, sound walls, waveguides and loud speakers. We formulate the design problem as a topology optimization problem, i.e. distribute material in a design domain...... such that the acoustic response is optimized....

  8. Pathway to a compact SASE FEL device

    Energy Technology Data Exchange (ETDEWEB)

    Dattoli, G., E-mail: giuseppe.dattoli@enea.it [ENEA – Centro Ricerche Frascati, Via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Di Palma, E. [ENEA – Centro Ricerche Frascati, Via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Petrillo, V. [Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); Rau, Julietta V. [Istituto di Struttura della Materia, ISM-CNR, Via del Fosso del Cavaliere, 100-00133 Rome (Italy); Sabia, E.; Spassovsky, I. [ENEA – Centro Ricerche Frascati, Via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Biedron, S.G.; Einstein, J.; Milton, S.V. [CSU – Colorado State University, Fort Collins, CO (United States)

    2015-10-21

    Newly developed high peak power lasers have opened the possibilities of driving coherent light sources operating with laser plasma accelerated beams and wave undulators. We speculate on the combination of these two concepts and show that the merging of the underlying technologies could lead to new and interesting possibilities to achieve truly compact, coherent radiator devices.

  9. WOCSDICE '98, 22nd Workshop on Compound Semiconductor Devices and Integrated Circuits, May 24-27, 1998, Pannonia Seehotel, Zeuthen, Germany

    National Research Council Canada - National Science Library

    1998-01-01

    .... Topics include material growth and characterization, recent developments in MESFETS, HEMTs, and HBTs, MMlC-Technology, Microwave and millimeter wave power devices, GaN- Devices, Mesoscopic devices...

  10. Atom Wave Interferometers

    National Research Council Canada - National Science Library

    Pritchard, David

    1999-01-01

    Matter wave interferometers, in which de Broglie waves are coherently split and then recombined to produce interference fringes, have opened exciting new possibilities for precision and fundamental...

  11. Hydraulic Evaluation and Optimisation of T. Basses Wave Turbine

    DEFF Research Database (Denmark)

    Frigaard, Peter; Kofoed, Jens Peter

    The present study investigates designs of the wing profiles and layouts of the wave turbine in order to optimize the design. Furthermore, the overall power production capability of the device has been estimated for the selected wing profiles and turbine layout.......The present study investigates designs of the wing profiles and layouts of the wave turbine in order to optimize the design. Furthermore, the overall power production capability of the device has been estimated for the selected wing profiles and turbine layout....

  12. Making structured metals transparent for ultrabroadband electromagnetic waves and acoustic waves

    International Nuclear Information System (INIS)

    Fan, Ren-Hao; Peng, Ru-Wen; Huang, Xian-Rong; Wang, Mu

    2015-01-01

    In this review, we present our recent work on making structured metals transparent for broadband electromagnetic waves and acoustic waves via excitation of surface waves. First, we theoretically show that one-dimensional metallic gratings can become transparent and completely antireflective for extremely broadband electromagnetic waves by relying on surface plasmons or spoof surface plasmons. Second, we experimentally demonstrate that metallic gratings with narrow slits are highly transparent for broadband terahertz waves at oblique incidence and high transmission efficiency is insensitive to the metal thickness. Further, we significantly develop oblique metal gratings transparent for broadband electromagnetic waves (including optical waves and terahertz ones) under normal incidence. In the third, we find the principles of broadband transparency for structured metals can be extended from one-dimensional metallic gratings to two-dimensional cases. Moreover, similar phenomena are found in sonic artificially metallic structures, which present the transparency for broadband acoustic waves. These investigations provide guidelines to develop many novel materials and devices, such as transparent conducting panels, antireflective solar cells, and other broadband metamaterials and stealth technologies. - Highlights: • Making structured metals transparent for ultrabroadband electromagnetic waves. • Non-resonant excitation of surface plasmons or spoof surface plasmons. • Sonic artificially metallic structures transparent for broadband acoustic waves

  13. Making structured metals transparent for ultrabroadband electromagnetic waves and acoustic waves

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Ren-Hao [National Laboratory of Solid State Microstructures and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); Peng, Ru-Wen, E-mail: rwpeng@nju.edu.cn [National Laboratory of Solid State Microstructures and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); Huang, Xian-Rong [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Wang, Mu [National Laboratory of Solid State Microstructures and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

    2015-07-15

    In this review, we present our recent work on making structured metals transparent for broadband electromagnetic waves and acoustic waves via excitation of surface waves. First, we theoretically show that one-dimensional metallic gratings can become transparent and completely antireflective for extremely broadband electromagnetic waves by relying on surface plasmons or spoof surface plasmons. Second, we experimentally demonstrate that metallic gratings with narrow slits are highly transparent for broadband terahertz waves at oblique incidence and high transmission efficiency is insensitive to the metal thickness. Further, we significantly develop oblique metal gratings transparent for broadband electromagnetic waves (including optical waves and terahertz ones) under normal incidence. In the third, we find the principles of broadband transparency for structured metals can be extended from one-dimensional metallic gratings to two-dimensional cases. Moreover, similar phenomena are found in sonic artificially metallic structures, which present the transparency for broadband acoustic waves. These investigations provide guidelines to develop many novel materials and devices, such as transparent conducting panels, antireflective solar cells, and other broadband metamaterials and stealth technologies. - Highlights: • Making structured metals transparent for ultrabroadband electromagnetic waves. • Non-resonant excitation of surface plasmons or spoof surface plasmons. • Sonic artificially metallic structures transparent for broadband acoustic waves.

  14. Advanced computational simulations of water waves interacting with wave energy converters

    Science.gov (United States)

    Pathak, Ashish; Freniere, Cole; Raessi, Mehdi

    2017-03-01

    Wave energy converter (WEC) devices harness the renewable ocean wave energy and convert it into useful forms of energy, e.g. mechanical or electrical. This paper presents an advanced 3D computational framework to study the interaction between water waves and WEC devices. The computational tool solves the full Navier-Stokes equations and considers all important effects impacting the device performance. To enable large-scale simulations in fast turnaround times, the computational solver was developed in an MPI parallel framework. A fast multigrid preconditioned solver is introduced to solve the computationally expensive pressure Poisson equation. The computational solver was applied to two surface-piercing WEC geometries: bottom-hinged cylinder and flap. Their numerically simulated response was validated against experimental data. Additional simulations were conducted to investigate the applicability of Froude scaling in predicting full-scale WEC response from the model experiments.

  15. Hydrodynamic Investigation of a Concentric Cylindrical OWC Wave Energy Converter

    Directory of Open Access Journals (Sweden)

    Yu Zhou

    2018-04-01

    Full Text Available A fixed, concentric, cylindrical oscillating water column (OWC wave energy converter (WEC is proposed for shallow offshore sites. Compared with the existing shoreline OWC device, this wave energy device is not restricted by the wave directions and coastline geography conditions. Analytical solutions are derived based on the linear potential-flow theory and eigen-function expansion technique to investigate hydrodynamic properties of the device. Three typical free-surface oscillation modes in the chamber are discussed, of which the piston-type mode makes the main contribution to the energy conversion. The effects of the geometrical parameters on the hydrodynamic properties are further investigated. The resonance frequency of the chamber, the power extraction efficiency, and the effective frequency bandwidth of the device is discussed, amongst other topics. It is found that the proposed OWC-WEC device with a lower draft and wider chamber breadth has better power extraction ability.

  16. Generating electricity at a breakwater in a moderate wave climate

    NARCIS (Netherlands)

    Schoolderman, J.; Reedijk, B.; Vrijling, J.K.; Molenaar, W.F.; Ten Oever, E.; Zijlema, M.

    2011-01-01

    A new concept for wave energy conversion is examined as a proof of concept for generating electricity in a moderate wave climate while being integrated in a caisson breakwater. Physical model testing is performed to analyse the preliminary efficiency of the device and to identify areas of

  17. Simplified Design Procedures for Moorings of Wave-Energy Converters

    DEFF Research Database (Denmark)

    Bergdahl, Lars; Kofoed, Jens Peter

    The goal of the report is that the reader shall be able to self-dependently make a first, preliminary analysis of wave-induced horizontal loads, motions and mooring forces for a moored floating wave energy device. Necessary prerequisites to attain that goal are the understanding of the physical p...

  18. WindWaveFloat (WWF): Final Scientific Report

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Alla; Roddier, Dominique; Banister, Kevin

    2012-03-30

    Principle Power Inc. and National Renewable Energy Lab (NREL) have completed a contract to assess the technical and economic feasibility of integrating wave energy converters into the WindFloat, resulting in a new concept called the WindWaveFloat (WWF). The concentration of several devices on one platform could offer a potential for both economic and operational advantages. Wind and wave energy converters can share the electrical cable and power transfer equipment to transport the electricity to shore. Access to multiple generation devices could be simplified, resulting in cost saving at the operational level. Overall capital costs may also be reduced, provided that the design of the foundation can be adapted to multiple devices with minimum modifications. Finally, the WindWaveFloat confers the ability to increase energy production from individual floating support structures, potentially leading to a reduction in levelized energy costs, an increase in the overall capacity factor, and greater stability of the electrical power delivered to the grid. The research conducted under this grant investigated the integration of several wave energy device types into the WindFloat platform. Several of the resulting system designs demonstrated technical feasibility, but the size and design constraints of the wave energy converters (technical and economic) make the WindWaveFloat concept economically unfeasible at this time. Not enough additional generation could be produced to make the additional expense associated with wave energy conversion integration into the WindFloat worthwhile.

  19. Electromagnetic mode conversion: understanding waves that suddenly change their nature

    International Nuclear Information System (INIS)

    Batchelor, D B; Berry, L A; Bonoli, P T; Carter, M D; Choi, M; D'Azevedo, E; D'Ippolito, D A; Gorelenkov, N; Harvey, R W; Jaeger, E F; Myra, J R; Okuda, H; Phillips, C K; Smithe, D N; Wright, J C

    2005-01-01

    In a magnetized plasma, such as in fusion devices or the Earth's magnetosphere, several different kinds of waves can simultaneously exist, having very different physical properties. Under the right conditions one wave can quite suddenly convert to another type. Depending on the case, this can be either a great benefit or a problem for the use of waves to heat and control fusion plasmas. Understanding and accurately modeling such behavior is a major computational challenge

  20. Surface acoustic wave oxygen pressure sensor

    Science.gov (United States)

    Oglesby, Donald M. (Inventor); Upchurch, Billy T. (Inventor); Leighty, Bradley D. (Inventor)

    1994-01-01

    A transducer for the measurement of absolute gas-state oxygen pressure from pressures of less than 100 Pa to atmospheric pressure (1.01 x 10(exp 5) Pa) is based on a standard surface acoustic wave (SAW) device. The piezoelectric material of the SAW device is coated with a compound which will selectively and reversibly bind oxygen. When oxygen is bound by the coating, the mass of the coating increases by an amount equal to the mass of the bound oxygen. Such an increase in the mass of the coating causes a corresponding decrease in the resonant frequency of the SAW device.