Challenges to Characterization of Sound Produced by Marine Energy Converters

Located off the Guérande peninsula, SEM-REV is the French maritime facility dedicated to the testing of wave energy converters and related components. Lead by Ecole Centrale de Nantes through the LHEEA laboratory, its aim is to promote research alongside the development of new offshore technologies. To this end, the 1km2, grid-connected zone is equipped with a comprehensive instruments network sensing met-ocean processes and especially waves, with two identical directional Waverider buoys deployed on the site since 2009. For the design of moored floating structures and, a fortiori, floating marine energy converters, the knowledge of the main wave resource — for regular operation — but also extreme conditions — for moorings and device survivability — has to be as precise as possible. Also, the consideration of the multiple wave systems (swell, wind sea) making up the sea state is a key asset for the support of developers before and during the testing phase. To this end, a spectral partitioning algorithm has been implemented which enables the individual characterisation of wave systems, in particular that of their spectral peakedness which is especially addressed in this work. Peakedness has been shown to be strongly related to the groupiness of large waves and is defined here as the standard JONSWAP’s peak enhancement factor γ. Statistics related to this quantity are derived from the measurement network, with a particular focus on the extreme conditions reported on SEM-REV (Joachim storm).

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Characterization and Applications of Diamond-like Nanocomposites: A Brief Review

Characterization and Application of Nanomaterials ◽

10.24294/can.v0i0.554 ◽

2018 ◽

Author(s):

Kalyan Adhikary ◽

Sayan Das ◽

Debasish De ◽

Anup Mondal ◽

Utpal Gangopadhyay ◽

...

Keyword(s):

Silicon Oxide ◽

High Ratio ◽

Atomic Scale ◽

Fourier Transformed Infrared Spectroscopy ◽

Marine Energy ◽

Deposition Parameters ◽

Free Air ◽

Wide Range ◽

Scale Network

Diamond-like Nanocomposites (DLN) is a newly member in amorphous carbon (a:C) family. It consists of two or more interpenetrated atomic scale network structure. The amorphous silicon oxide (a:SiO) is incorporated within diamond-like carbon (DLC) matrix i.e. a:CH and both the network is interpenetrated by Si-C bond. Hence, the internal stress of deposited DLN film decreases remarkably compare to DLC. The diamond like properties has come due to deform tetrahedral carbon with sp3 configuration and high ratio of sp3 to sp2 bond. The DLN has excellent mechanical, electrical, optical and tribological properties. Those the properties of DLN could be varied over a wide range by changing deposition parameters, precursor and even post deposition treatment also. The range of properties are : Resistivity 10-4 to 1014 Ωcm, hardness 10–22 GPa, coefficient of friction 0.03-0.2, wear factor 0.2-0.4 10-7mm3/Nm, transmission Vis-far IR, modulus of elasticity 150-200 GPa, residual stress 200-300 Mpa, Dielectric constant 3-9 and maximum operating temperature 6000C in oxygen environment and 12000C in O2 free air. Generally, the PECVD method is used to synthesis the DLN film. The most common procedures used for investigation of structure and composition of DLN films are Raman spectroscopy, Fourier transformed infrared spectroscopy (FTIR), HRTEM, FESEM and X-ray photo electron spectroscopy (XPS). Interest in the coating technology has been expressed by nearly every industrial segment including automotive, aerospace, chemical processing, marine, energy, personal care, office equipment, electronics, biomedical and tool and die or in a single line from data to beer in all segment of life. In this review paper, characterization of Diamond-like Nanocomposites is discussed and subsequently different application areas are also elaborated.

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Certification of Marine Energy Converters: The Experience So Far

Volume 5: Ocean Space Utilization; Polar and Arctic Sciences and Technology; The Robert Dean Symposium on Coastal and Ocean Engineering; Special Symposium on Offshore Renewable Energy ◽

10.1115/omae2007-29258 ◽

2007 ◽

Author(s):

Claudio Bittencourt Ferreira

Keyword(s):

New Technology ◽

Third Party ◽

Functional Requirements ◽

Energy Converter ◽

The Past ◽

Wave Energy Converters ◽

Marine Energy ◽

Constraints Handling ◽

The Right ◽

Energy Converters

In the past few years, DNV has been involved in a variety of projects related to marine energy converters. All projects have been characterised for the handling of technical uncertainties due to the application of new technology or proven technology in different area of application. A systematic approach based on the DNV RP-A203 Qualification of New Technology [1] was applied combined with the Guidelines for Design and Operation of Wave Energy Converters [2] to steer the third party activity, but, more importantly, to allow developers to systematically identify and deal with the risks in a rational manner with traceability of decisions throughout the development of the energy converter. From the very start of our engagement, it was clear that the handling of technical uncertainties was affected, not only by the technical barriers, but also by financial and time constraints. The establishment of the safety and functional targets to be achieved by the energy converter are to be based, not only on the safety and asset integrity aspects, but also on the financial / business model. The experience of using the Qualification process and the Guidelines on these projects, achieving the right balance between the constraints, handling of uncertainties, financial targets and safety and functional requirements, are briefly described in this paper as well as the future steps to be taken to improve the process and consolidate the experience so far. In this paper, it is also addressed the use of the DNV OSS-312 [3] on the certification process of marine energy converters.

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