Search

This paper documents the round robin testing campaign carried out on a floating wind turbine as part of the EU H2020 MaRINET2 project. A 1/60th scale model of a 10 MW floating platform was tested in wave basins in four different locations around Europe. The tests carried out in each facility included decay tests, tests in regular and irregular waves with and without wind thrust, and tests to characterise the mooring system as well as the model itself. For the tests in wind, only the thrust of the turbine was considered and it was fixed to pre-selected levels. Hence, this work focuses on the hydrodynamic responses of a semi-submersible floating foundation. It was found that the global surge stiffness was comparable across facilities, except in one case where different azimuth angles were used for the mooring lines. Heave and pitch had the same stiffness coefficient and periods for all basins. Response Amplitude Operators (RAOs) were used to compare the responses in waves from all facilities. The shape of the motion RAOs were globally similar for all basins except around some particular frequencies. As the results were non-linear around the resonance and cancellation frequencies, the differences between facilities were magnified at these frequencies. Surge motions were significantly impacted by reflections leading to large differences in these RAOs between all basins.

This paper introduces metrics developed for analysing irregular wave test results from the round robin testing campaign carried out on a floating wind turbine as part of the EU H2020 MaRINET2 project. A 1/60th scale model of a 10 MW floating platform was tested in wave basins in four different locations around Europe. The tests carried out in each facility included decay tests, tests in regular and irregular waves with and without wind thrust, and tests to characterise the mooring system as well as the model itself. While response amplitude operations (RAOs) are a useful tool for assessing device performance in irregular waves, they are not easy to interpret when performing an inter-facility comparison where there are many variables. Metrics that use a single value per test condition rather than an RAO curve are a means of efficiently comparing tests from different basins in a more heuristic manner. In this research, the focus is on using metrics to assess how the platform responds with varying wave height and thrust across different facilities. It is found that the metrics implemented are very useful for extracting global trends across different basins and test conditions.

The EU H2020 MaRINET2 project has a goal to improve the quality, robustness and accuracy of physical modelling and associated testing practices for the offshore renewable energy sector. To support this aim, a round robin scale physical modelling test programme was conducted to deploy a common wave energy converter at four wave basins operated by MaRINET2 partners. Test campaigns were conducted at each facility to a common specification and test matrix, providing the unique opportunity for intercomparison between facilities and working practices. A nonproprietary hinged raft, with a nominal scale of 1:25, was tested under a set of 12 irregular sea states. This allowed for an assessment of power output, hinge angles, mooring loads, and six-degree-of-freedom motions. The key outcome to be concluded from the results is that the facilities performed consistently, with the majority of variation linked to differences in sea state calibration. A variation of 5?10% in mean power was typical and was consistent with the variability observed in the measured significant wave heights. The tank depth (which varied from 2?5 m) showed remarkably little influence on the results, although it is noted that these tests used an aerial mooring system with the geometry unaffected by the tank depth. Similar good agreement was seen in the heave, surge, pitch and hinge angle responses. In order to maintain and improve the consistency across laboratories, we make recommendations on characterising and calibrating the tank environment and stress the importance of the device?facility physical interface (the aerial mooring in this case). his research was funded by the European Union’s Horizon 2020 research and innovation programme under Grant Agreement Number 731084, Project MaRINET2 (Marine Renewable Infrastructure Network for Enhancing Technologies 2).

We investigate experimentally the time evolution of the wetted surface during the lifting of a body initially floating at the water surface. This phenomenon is referred to as the water exit problem. The water exit experiments were conducted with transparent (PMMA) mock-ups of two different shapes: a circular disc and a square flat plate. Two different lighting systems were used to diffuse light in the mock-up material: a central high-power LED light normal to the surface and an edge-lighting system featuring an array of LED lights. These setups make it possible to illuminate the contact line, which delimits the surface of contact between the mock-up and the water. The characteristic size of the mock-ups is about 20 cm and the acceleration of the mock-up oscillates between 0 and 25 m/ $$\mathrm{s}^2$$ . We show that the central light setup gives satisfactory results for the circular disc and that the edge lighting technique makes it possible to follow a contact line with a time-evolving complex shape (strong changes of convexity) up to 1000 fps. The observations presented in the paper support the possibility of extending this promising technique to more general three-dimensional bodies with arbitrary motion (e.g., including pitch motion).

A Raman microspectrophotometer is described that allows the spectroscopic investigation of protein crystals under exactly the same conditions as those used for X-ray data collection. The concept is based on the integration of the Raman excitation/collection optics into a microspectrophotometer built around a single-axis diffractometer and a cooling device. It is shown that Raman spectra of outstanding quality can be recorded from crystallized macromolecules under non-resonant conditions. It is proposed that equipment developed in the context of macromolecular cryocrystallography, such as commonly used cryoloops, can be advantageously used to improve the quality of Raman spectra. In a few examples, it is shown that Raman microspectrophotometry provides crucial complementary information to X-ray crystallography,e.g.identifying the chemical nature of unknown features discovered in electron-density maps, or following ligand-binding kinetics in biological crystals. The feasibility of `online' Raman measurements performed directly on the ESRF macromolecular crystallography beamlines has been investigated and constitutes a promising perspective for the routine implementation of combined spectroscopic and crystallographic methods.In crystalloRaman spectroscopy efficiently complements absorption/fluorescence microspectrophotometry for the study of biological crystals and opens up new avenues for difficult structural projects with mechanistic perspectives in the field of protein crystallography.

Synchrotrons are now producing thousands of macromolecular structures each year. The need for complementary techniques available on site has progressively emerged, either to assess the relevance of the structure of a protein or to monitor changes that may occur during X-ray diffraction data collection. Microspectrophotometers in the UV-visible absorbance or fluorescence mode have evolved over the past few decades to become the instruments of choice to perform such tests. Described here are recent improvements to the microspectrophotometer of the so-called Cryobench laboratory located at the European Synchrotron Radiation Facility, Grenoble, France. Optical and mechanical properties have been enhanced so as to record better spectra on smaller samples. A device has been implemented to measure the signal decay of fluorescent samples, either in the crystalline or in the solution state. Recording of the fluorescence lifetime in addition to the steady-state fluorescence emission spectrum allows precise monitoring of the fluorescent sample under study. The device consists of an adaptation of a commercially available time-correlated single-photon-counting (TCSPC) system. A method to record and analyze series of TCSPC histograms, e. g. collected as a function of temperature, is described. To validate the instruments, fluorescence lifetimes of fluorescent small molecules or proteins in the crystalline or solution state, at room and cryo temperatures, have been measured. Lifetimes of a number of fluorescent proteins of the GFP family were generally found to be shorter in crystals than in solution, and slightly longer at cryo temperatures than at ambient temperature. The possibility of performing fluorescence lifetime measurements on crystals at synchrotron facilities widens the variety of spectroscopic techniques complementing X-ray diffraction on macromolecular crystallography beamlines. ispartof: Journal of Applied Crystallography vol:40 pages:1105-1112 status: published

The design of wave energy mooring systems is challenging: overdesign incurs a significant cost penalty, underdesign may lead to a premature failure and incorrect design could reduce the power production. Consequently, compliant mooring systems are being developed for wave energy applications. This paper presents tank test results for a scale model of the buoy and mooring used at the South West Mooring Test Facility (SWMTF), an offshore facility developed to conduct long-term sea trials for wave energy device moorings. A compliant three leg catenary mooring system using Nylon ropes in the water column is investigated. Preliminary static, quasi-static, decay, regular and irregular wave tests were conducted on the 1:5 scale model, using the Ifremer basin in Brest. A corresponding numerical model was developed with a time-domain mooring modelling tool, inputting hydrodynamic data from a radiation/diffraction potential modelling program. After the calibration of several hydrodynamic parameters, the numerical model demonstrated good agreement with the experiment. However, numerical results show large differences with the field test results, mainly because of unknowns in the anchor position. The methods and procedures presented will allow the effective validation of numerical models to enable the development of appropriate mooring systems in wave energy applications.

Structural proteomics has promoted the rapid development of automated protein structure determination using X-ray crystallography. Robotics are now routinely used along the pipeline from genes to protein structures. However, a bottleneck still remains. At synchrotron beamlines, the success rate of automated sample alignment along the X-ray beam is limited by difficulties in visualization of protein crystals, especially when they are small and embedded in mother liquor. Despite considerable improvement in optical microscopes, the use of visible light transmitted or reflected by the sample may result in poor or misleading contrast. Here, the endogenous fluorescence from aromatic amino acids has been used to identify even tiny or weakly fluorescent crystals with a high success rate. The use of a compact laser at 266 nm in combination with non-fluorescent sample holders provides an efficient solution to collect high-contrast fluorescence images in a few milliseconds and using standard camera optics. The best image quality was obtained with direct illumination through a viewing system coaxial with the UV beam. Crystallographic data suggest that the employed UV exposures do not generate detectable structural damage.

CATS allows users to mount and dismount their crystal samples remotely on the diffractometer, without entering the experimental hutch. CATS has been integrated into the automated control of FIP, allowing users to choose the wavelengths, optimize the beam intensity, mount and screen their crystal sample automatically and finally record diffraction data on the best sample(s).

The WINFLO project (Wind turbine with INnovative design for Floating Lightweight Offshore) aims at the development of competitive floating offshore wind turbines, by a consortium of 3 industrial partners (Nass&Wind Industrie, DCNS and Vergnet SA) and 2 scientific partners (IFREMER and ENSTA Bretagne). The design of the floater is an innovative semi-submersible free floating platform with particular aspects. Classical steps toward the assessment of the hydrodynamic and energy production performance include numerical modeling, model scale tank testing and intermediate or full scale tests at sea. The present study describes the wave tank tests including wind generation compared to some numerical modeling results of the coupled system composed of the support floater and the wind turbine.Copyright © 2013 by ASME

International audience; Microfluidic devices were designed to perform on micromoles of biological macromolecules and viruses the search and the optimization of crystallization conditions by counter-diffusion, as well as the on-chip analysis of crystals by X-ray diffraction. Chips composed of microchannels were fabricated in poly-dimethylsiloxane (PDMS), poly-methyl-methacrylate (PMMA) and cyclo-olefin-copolymer (COC) by three distinct methods, namely replica casting, laser ablation and hot embossing. The geometry of the channels was chosen to ensure that crystallization occurs in a convection-free environment. The transparency of the materials is compatible with crystal growth monitoring by optical microscopy. The quality of the protein 3D structures derived from on-chip crystal analysis by X-ray diffraction using a synchrotron radiation was used to identify the most appropriate polymers. Altogether the results demonstrate that for a novel biomolecule, all steps from the initial search of crystallization conditions to X-ray diffraction data collection for 3D structure determination can be performed in a single chip.

International audience; A bamboo foam is the simplest case of an ordered foam confined in a narrow channel. It is made of a regular film distribution, arranged perpendicularly to the channel. Our work consists of studying the structural properties of several films taken in a drained foam. X-ray experiments highlighted the equality of the equilibrium thickness for each film within a foam. The same thickness was found as by measurements of disjoining pressure isotherms, proving as well that films of a bamboo foam behave like isolated ones. The refinement of X-ray data by a simple model of specular reflectivity showed a significant variation of the electronic distribution of the surfactant layer for a common black film forwarding from one equilibrium state to another. A discussion on the organization of the surfactant molecules to the gas/liquid interface and film is proposed.

Iron-peroxide intermediates are central in the reaction cycle of many iron-containing biomolecules. We trapped iron(III)-(hydro) peroxo species in crystals of superoxide reductase (SOR), a nonheme mononuclear iron enzyme that scavenges superoxide radicals. X-ray diffraction data at 1.95 angstrom resolution and Raman spectra recorded in crystallo revealed iron-(hydro) peroxo intermediates with the ( hydro) peroxo group bound end-on. The dynamic SOR active site promotes the formation of transient hydrogen bond networks, which presumably assist the cleavage of the iron- oxygen bond in order to release the reaction product, hydrogen peroxide. ispartof: Science vol:316 issue:5823 pages:449-453 status: published

Crystallogenesis, usually based on the vapor diffusion method, is currently considered one of the most difficult steps in macromolecular X-ray crystallography. Due to the increasing number of crystallization assays performed by protein crystallographers, several automated analysis methods are under development. Most of these methods are based on microscope images and shape recognition. We propose an alternative method of identifying protein crystals: by directly exposing the crystallization drops to an X-ray beam. The resulting diffraction provides far more information than classical microscope images. Not only is the presence of diffracting crystals revealed, but also a first estimation of the space group, cell parameters, and mosaicity is obtained. In certain cases, it is also possible to collect enough data to verify the presence of a specific substrate or a heavy atom. All these steps are performed without the sometimes tedious necessity of removing crystals from their crystallization drop.

Protein crystallography is becoming a popular technique that is routinely used to access structural information. At one end of the process, sample preparation is now facilitated by commercially available crystallization kits. At the other end, structure determination has been made easier by automated software. Data collection, the step in between, is now usually performed on synchrotron sources. However, it is still restricted to experienced users and requires significant help from beamline staff. Part of this difficulty arises from the sophisticated experimental setup, which comprises a goniometer, a magnetic head, a device for changing the sample and monitoring accessories. It was proposed that this setup could be simplified by replacing these elements by a robotic arm that can perform all of the required tasks. In the present paper, it is demonstrated that this new setup can be used on a synchrotron beamline to mount and centre the sample and to collect diffraction data. This new system completely changes the design of the experimental setup by merging functions that were previously considered to be distinct. Moreover, automation of sample handling need not be considered as a specific development and is now included in a unique multipurpose device.

“The Blue Growth Farm” is an ongoing H2020 European project, aimed to the development, engineering and demonstration of a new floating multi-purpose platform concept, devoted to aquaculture, and wind-wave energy production. Due to the significant complexity of the coupled dynamic behavior of the pro-posed concept, model tests are essential to investigate the most relevant physical phenomena and vali-date/calibrate the pertinent numerical models. However, the realization of a scaled model of such structure is by itself quite challenging, since each sub-system follows its own scaling laws and requires different strate-gies to minimize scale effects. The aim of the present paper is to describe the arrangement of the experi-mental activities, discussing the mechanisms of the scale factor at different scales and related results accuracy, scaling strategies and test environments. The two-phase framework and the scaling strategies proposed may be also useful for future activities on similar concepts.