Zeitschriftenartikel: „Off-shore structures“

1

Mortada, Mohamed, Mohamed Ahmed, Mohamed Morad und Ahmed Alkaisy. „Sediment Transport Fields Around Off-Shore and On-Shore Structures“. Fayoum University Journal of Engineering 4, Nr. 2 (01.06.2021): 139–56. http://dx.doi.org/10.21608/fuje.2021.205539.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

2

Hanzawa, Minoru, Akira Matsumoto und Hitoshi Tanaka. „STABILITY OF WAVE-DISSIPATING CONCRETE BLOCKS OF DETACHED BREAKWATERS AGAINST TSUNAMI“. Coastal Engineering Proceedings 1, Nr. 33 (15.10.2012): 24. http://dx.doi.org/10.9753/icce.v33.structures.24.

Der volle Inhalt der Quelle

Annotation:

In recent years, the risk of occurrence of tsunamis generated by near shore earthquakes, such as, Tokai, Tonankai, Nankai and off-Miyagi is considered to be higher than before, as well as off shore tsunamis traveling long distances, e.g., the 2010 Chilean tsunami. On March, 11th, 2011 the huge, devastating tsunami generated by The 2011 off the Pacific coast of Tohoku Earthquake attacked and damaged the east coast area of Japan. Tsunami forces onto vertical walls, such as seawalls, has already been studied in detail, e.g., Asakura et al.(2002) and Kato et al.(2006). In Japan, detached breakwaters made with wave-dissipating concrete blocks such as Tetrapods have been widely applied. However, the effects of detached breakwater on tsunami disaster mitigation have not been studied. In our study, hydraulic model tests have been systematically and carefully carried out using solitary tsunami waves to evaluate the stability of concrete blocks following the our previous study on the effect of detached breakwaters from the viewpoint of reducing run-up and wave pressure onto seawalls behind the detached breakwaters (Hanzawa et al., 2011).

APA, Harvard, Vancouver, ISO und andere Zitierweisen

3

Salvadori, Gianfausto, Giuseppe Roberto Tomasicchio und Felice D'Alessandro. „Multivariate approach to design coastal and off-shore structures“. Journal of Coastal Research 65 (02.01.2013): 386–91. http://dx.doi.org/10.2112/si65-066.1.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

4

Ragab, Ahmed, und Chung C. Fu. „Nonlinear free vibration of fixed off-shore framed structures“. Computers & Structures 21, Nr. 6 (Januar 1985): 1373–78. http://dx.doi.org/10.1016/0045-7949(85)90191-9.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

5

Tomasicchio, Giuseppe Roberto, Elvira Armenio, Felice D'Alessandro, Nuno Fonseca, Spyros A. Mavrakos, Valery Penchev, Holger Schuttrumpf, Spyridon Voutsinas, Jens Kirkegaard und Palle M. Jensen. „DESIGN OF A 3D PHYSICAL AND NUMERICAL EXPERIMENT ON FLOATING OFF-SHORE WIND TURBINES“. Coastal Engineering Proceedings 1, Nr. 33 (14.12.2012): 67. http://dx.doi.org/10.9753/icce.v33.structures.67.

Der volle Inhalt der Quelle

Annotation:

The knowledge of the behavior of floating offshore wind turbines (W/T) under wave and/or wind action remains one of the most difficult challenges in offshore engineering which is mostly due to the highly non-linear response of the structure. The present study describes the design process of a 3D physical experiment to investigate the behavior of the most promising structure technology of floating W/T: spar buoy (SB) and tension leg platform (TLP) under different meteo conditions. In order to properly design the two W/T models, the following topics have been analyzed: mooring lines, mass distribution, appropriate scaling factor and data relative to the geometrical characteristics, wave basin dimensions and wind and waves conditions. In addition, the Smoothed Particle Hydrodynamics method (SPH) (Monaghan 1994) has been considered to simulate the 3D behavior of a floating offshore W/T. In particular, the SPH, calibrated and verified on the basis of the experimental observations, may represent a reliable tool for preliminary test of changes in the floater geometry.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

6

Moarefzadeh, M. R., und R. E. Melchers. „Sample-specific linearization in reliability analysis of off-shore structures“. Structural Safety 18, Nr. 2-3 (Januar 1996): 101–22. http://dx.doi.org/10.1016/0167-4730(96)00014-8.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

7

Emi, Hirohiko, Michifumi Yuasa, Atsushi Kumano, Hiroyuki Kumamoto, Norio Yamamoto und Masaki Matsunaga. „A Study on Life Assessment of Ships and Off-shore Structures“. Journal of the Society of Naval Architects of Japan 1992, Nr. 172 (1992): 627–35. http://dx.doi.org/10.2534/jjasnaoe1968.1992.172_627.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

8

Emi, Hirohiko, Michifumi Yuasa, Atushi Kumano, Toshirou Arima, Norio Yamamoto und Masatoshi Umino. „A Study on Life Assessment of Ships and Off-Shore Structures“. Journal of the Society of Naval Architects of Japan 1993, Nr. 174 (1993): 735–44. http://dx.doi.org/10.2534/jjasnaoe1968.1993.174_735.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

9

WEST, BRUCE J. „EXTREMA OF FRACTAL RANDOM WATER WAVES“. International Journal of Modern Physics B 10, Nr. 01 (10.01.1996): 67–132. http://dx.doi.org/10.1142/s0217979296000052.

Der volle Inhalt der Quelle

Annotation:

Herein we review the statistical properties of the visibly random behavior of sea waves and the resulting stochastic forces loading off-shore structures and ships. The traditional assumption is that the statistics of the sea surface displacement produced by waves is Gaussian, or equivalently that the statistics of the wave amplitudes are Rayleigh. We examine this and a more general statistical hypothesis in this review, that being that the statistics of surface waves are Lévy stable, and investigate the response of dynamical models of off-shore structures to such stochastic forcing. We find that such familiar results as the Weibull distribution for the failure of a dynamical system may be a consequence of the statistics of the driver rather than any nonlinearity in the structure response.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

10

Lin, Jung-Tai. „EMPIRICAL PREDICTION OF WAVE SPECTRUM FOR WIND-GENERATED GRAVITY WAVES“. Coastal Engineering Proceedings 1, Nr. 20 (29.01.1986): 36. http://dx.doi.org/10.9753/icce.v20.36.

Der volle Inhalt der Quelle

Annotation:

Wind-Generated gravity wave has been of great interest to researchers and engineers in the field of coastal engineering because it is one of the important considerations in the engineering studies and designs for ship navigation, coastal and off-shore structures, shore protection, oil pollution control, and wave energy conversion. An accurate prediction of the wave height, wave frequency, and wave spectrum is critical to the success of these engineering studies and design.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

11

Vugteveen, Henk. „PIB Coatings for Off-Shore Rehabilitation of Pipes and Structures (above and underwater)“. Rio Oil and Gas Expo and Conference 22, Nr. 2022 (26.09.2022): 433–34. http://dx.doi.org/10.48072/2525-7579.rog.2022.433.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

12

Stoliarchuk, Yaroslava, Denys Ilnytskyy und Glib Turolev. „GLOBAL BUSINESS NETWORK: OFF-SHORE MODEL’S DIVERSIFICATION AND IMPACT“. Economics & Education 5, Nr. 2 (25.04.2020): 20–29. http://dx.doi.org/10.30525/2500-946x/2020-2-3.

Der volle Inhalt der Quelle

Annotation:

Modern literature lacks systematization and assessment of impact of network of international corporations and their off-shore models on development of national economies in post-industrial times. There is variety of tools besides well-known multinational corporate accounting policies and strategies of MNCs that provide mechanism for the management of transaction costs in reporting period, thus reducing the amount of taxable profit due to application of the method of accelerated depreciation and channels of tax deferrals, which allow to reduce corporate tax payments owing to the objective reduction of real purchasing power of money over time. The purpose of the article is to propose in-depth systematization of balanced pros and cons for further development of national FDI policies aimed at network of MNCs. The paper utilizes a compound methodology of review and systematization to calculate overall impact of offshoring that exceeds 1% of global GDP. While modern financial and economic activities of MNC’s distinguish both internal and external offshoring, the paper focuses upon endogenous one. The key attention is on dominant ones – tax inversion phenomenon is known as base erosion and profit shifting, tax planning strategies, international debt shifting, models of tax treaty shopping, tax deferral, tax hybrids, strategic transfer pricing tools. In business and financial management MNCs resort to the development of extremely complex network structures of parent and subsidiary companies in order to increase international competitive advantages. MNCs make special efforts to recruit staff capable of effectively performing key functions in the field of corporate offshoring. We find huge regional asymmetries in MNCs impact on development of national economies. On one hand, a number of highly profitable corporations pay almost zero tax in favour of their countries of registration; on the other, MNCs create jobs, markets, volumes and asymmetries of geographical structure of differences in the value of goods and services supplied through international trade between developing and developed countries due to enormous scale of business offshoring.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

13

GÜRÇAY, Savas, und Günay ÇİFTÇİ. „CHIRP-ENGINEERING SEISMIC METHOD FOR EXPLORING SEABED AND UNDERWATER STRUCTURES: OFF-SHORE WESTERN ANATOLIA“. Journal of Scientific Perspectives 4, Nr. 3 (05.08.2020): 217–22. http://dx.doi.org/10.26900/jsp.4.018.

Der volle Inhalt der Quelle

Annotation:

CHIRP systems are widely used in seabed sediment classification, submarine faults, positioning of marine engineering structures, pipeline geotechnical studies, platform and well area assessments, archaeological and environmental impact assessments. The resolution of the system is in the order of decimeter. In this study, the characteristics of submarine active faults, buried faults, seabed and underlying layers in the region were analyzed and interpreted by CHIRP data collected off-shore Seferihisar, Teke Peninsula and Alaçatı.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

14

Okupnik, E. I., S. N. Zhiznyakov, L. L. Rubanovich, V. I. Novikov, V. N. Gorpneyuk, O. I. Steklov, E. A. Makhmudov, G. I. Khanguliev und T. Sh Shirinov. „Assembly welding of one‐sided joints in structures of deep‐water stationary off‐shore platforms“. Welding International 7, Nr. 4 (Januar 1993): 296–300. http://dx.doi.org/10.1080/09507119309548393.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

15

Liščić, Božidar, Ivo Senjanović, Većeslav Čorić, Hrvoje Kozmar, Marko Tomić und Neven Hadžić. „Off shore Wind Power Plant in the Adriatic Sea: An Opportunity for the Croatian Economy“. Transactions on Maritime Science 3, Nr. 2 (21.10.2014): 103–10. http://dx.doi.org/10.7225/toms.v03.n02.001.

Der volle Inhalt der Quelle

Annotation:

The significant growth of renewable energy production in the past decades is present mainly due to the global depletion of fossil fuel reserves. One of interesting and well developed renewable energy technologies are wind turbines which are mainly built onshore. Due to more favorable wind characteristics at sea, off shore wind power plants are an interesting and challenging option for meeting future energy demands. In particular, less turbulent wind with higher average velocity enhances energy production and reduces structural fatigue of wind energy structures. In this study, benefits and drawbacks of off shore wind turbine units and power plants are pointed out. Based on the available climate data, sea depths and existing sea traffic routes, two possible wind power plants, i.e. one with fixed and another with floating turbines, are proposed for installation in the Croatian part of the Adriatic Sea. Benefits for the Croatian shipbuilding industry and its economy are pointed out.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

16

Passchier, Sandra, Kenneth Rijsdijk und Cees Laban. „Introduction“. Netherlands Journal of Geosciences 84, Nr. 2 (Juli 2005): 59. http://dx.doi.org/10.1017/s0016774600022952.

Der volle Inhalt der Quelle

Annotation:

Coastal low-lands are densely populated areas characterized by large economic activity. The shallow subsurface plays an important role because of geotechnical requirements for the foundation of structures and its potential for natural resources, such as sand, gravel, and groundwater. The application of geo-scientific data requires that the subsurface is represented as 2D and 3D models displaying the stratigraphie relations of sedimentary rock units, both on-and off-shore.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

17

Vigneron, Adrien, Perrine Cruaud, Frederic Ducellier, Ian M. Head und Nicolas Tsesmetzis. „Syntrophic Hydrocarbon Degradation in a Decommissioned Off-Shore Subsea Oil Storage Structure“. Microorganisms 9, Nr. 2 (11.02.2021): 356. http://dx.doi.org/10.3390/microorganisms9020356.

Der volle Inhalt der Quelle

Annotation:

Over the last decade, metagenomic studies have revealed the impact of oil production on the microbial ecology of petroleum reservoirs. However, despite their fundamental roles in bioremediation of hydrocarbons, biocorrosion, biofouling and hydrogen sulfide production, oil field and oil production infrastructure microbiomes are poorly explored. Understanding of microbial activities within oil production facilities is therefore crucial for environmental risk mitigation, most notably during decommissioning. The analysis of the planktonic microbial community from the aqueous phase of a subsea oil-storage structure was conducted. This concrete structure was part of the production platform of the Brent oil field (North Sea), which is currently undergoing decommissioning. Quantification and sequencing of microbial 16S rRNA genes, metagenomic analysis and reconstruction of metagenome assembled genomes (MAGs) revealed a unique microbiome, strongly dominated by organisms related to Dethiosulfatibacter and Cloacimonadetes. Consistent with the hydrocarbon content in the aqueous phase of the structure, a strong potential for degradation of low molecular weight aromatic hydrocarbons was apparent in the microbial community. These degradation pathways were associated with taxonomically diverse microorganisms, including the predominant Dethiosulfatibacter and Cloacimonadetes lineages, expanding the list of potential hydrocarbon degraders. Genes associated with direct and indirect interspecies exchanges (multiheme type-C cytochromes, hydrogenases and formate/acetate metabolism) were widespread in the community, suggesting potential syntrophic hydrocarbon degradation processes in the system. Our results illustrate the importance of genomic data for informing decommissioning strategies in marine environments and reveal that hydrocarbon-degrading community composition and metabolisms in man-made marine structures might differ markedly from natural hydrocarbon-rich marine environments.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

18

Pietri, Alice, Pierre Testor, Vincent Echevin, Alexis Chaigneau, Laurent Mortier, Gerard Eldin und Carmen Grados. „Finescale Vertical Structure of the Upwelling System off Southern Peru as Observed from Glider Data“. Journal of Physical Oceanography 43, Nr. 3 (01.03.2013): 631–46. http://dx.doi.org/10.1175/jpo-d-12-035.1.

Der volle Inhalt der Quelle

Annotation:

Abstract The upwelling system off southern Peru has been observed using an autonomous underwater vehicle (a Slocum glider) during October–November 2008. Nine cross-front sections have been carried out across an intense upwelling cell near 14°S. During almost two months, profiles of temperature, salinity, and fluorescence were collected at less than 1-km resolution, between the surface and 200-m depth. Estimates of alongshore absolute geostrophic velocities were inferred from the density field and the glider drift between two surfacings. In the frontal region, salinity and biogeochemical fields displayed cross-shore submesoscale filamentary structures throughout the mission. Those features presented a width of 10–20 km, a vertical extent of ~150 m, and appeared to propagate toward the shore. They were steeper than isopycnals and kept an aspect ratio close to f/N, the inverse of the Prandtl ratio. These filamentary structures may be interpreted mainly as a manifestation of submesoscale turbulence through stirring of the salinity gradients by the mesoscale eddy field. However, meandering of the front or cross-frontal wind-driven instabilities could also play a role in inducing vertical velocities.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

19

Magray, Adil Ahmad, Amanpreet Tangri, Zehra Khan und Naiyara Khan. „Foundation engineering for offshore gravity structures“. IOP Conference Series: Earth and Environmental Science 889, Nr. 1 (01.11.2021): 012053. http://dx.doi.org/10.1088/1755-1315/889/1/012053.

Der volle Inhalt der Quelle

Annotation:

Abstract Gravity based structures are in play from early times. Numerous structures are being installed around the globe. These structures had shown a rigid face towards the harsh conditions/situation in the offshore environment. The key factors for sustainability are geotechnical design and the sub soil survey. These structures are used for collection, transport and also for temporary storage of crude gas and oil. These structures serve as a bridge between the much need fuel and the modern world. The installation of GBS involves major wings of modern engineering i.e. Mechanical, Structural, architecture and Geotechnical engineering because these structures are a great challenge as considering the harsh and hard off shore conditions. These structures are having a much importance apart from its features i.e. from the point of economy, as the oil prices are touching the heights, it influences construction of GBS. Now a days most of the multinational companies are focusing towards the construction of offshore GBS, as well as paying much attention on research work off these structures because to make huge profit. In this paper an effort has been made to understand the different aspects which are related to GBS i.e. pre-construction operations, soil investigation, construction, installment and some of the safety aspects as considering it one of the most focused topics now and in future.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

20

MIURA, Fusanori, Itsuo NOZAWA, Nobuaki SAKAKI und Katsushi HIRANO. „The effect of ice on the seismic response and dynamic stability against sliding of off-shore structures.“ Doboku Gakkai Ronbunshu, Nr. 409 (1989): 65–73. http://dx.doi.org/10.2208/jscej.1989.409_65.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

21

Grammatikos, Sotirios A., Ryan G. Jones, Mark Evernden und Joao R. Correia. „Thermal cycling effects on the durability of a pultruded GFRP material for off-shore civil engineering structures“. Composite Structures 153 (Oktober 2016): 297–310. http://dx.doi.org/10.1016/j.compstruct.2016.05.085.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

22

Kahai, Harjot Singh, Mayur Paliwal und Sumit Geete. „Experimental Study on Hematite Concreting“. Materials Science Forum 866 (August 2016): 49–52. http://dx.doi.org/10.4028/www.scientific.net/msf.866.49.

Der volle Inhalt der Quelle

Annotation:

High Density concrete is commonly used for radiation shielding of nuclear-reactors and other structures like counter weights, coating of off-shore pipelines. High Density concrete or is designed by using heavy weight aggregates such as hematite, magnetite, barite etc. The material is called hematite is used in this special concrete. The mix used is for OPC 43grade of cement. High density concrete can be designed in same way as normal weight concretes, but the additional self-weight should be taken into account.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

23

Graversen, Ole. „Upper Triassic – Cretaceous stratigraphy and structural inversion off-shore SW Bornholm, Tornquist Zone, Denmark“. Bulletin of the Geological Society of Denmark 51 (15.12.2004): 111–36. http://dx.doi.org/10.37570/bgsd-2004-51-08.

Der volle Inhalt der Quelle

Annotation:

Geological interpretations by various authors of exploration reflection seismic data offshore SW Bornholm show good agreement for the Rønne Graben. However, major differences exist regarding the Mesozoic stratigraphy and structural development of the Arnager-Darlowo Block and the Risebæk Graben. Major problems relate to the distribution and structural position of the Jurassic, and interpretation of inversion structures in the Rønne and Kolobrzeg grabens along the Arnager Block. In addition to the Pernille-1 and Stina-1 wells that document the stratigraphy of the Rønne and Kolobrzeg graben sections, the bedrock geology along the south coast of Bornholm is discussed.The Jurassic is established as a major constituent of the Arnager Block above the Risebæk Graben, in contrast to previous interpretations. The revised stratigraphy and reinterpretation of the inversion zones help to establish a new interval of basin inversion during the Jurassic – Early Cretaceous priorto the Late Cretaceous inversion. Analysis of the Late Cretaceous inversion across the Rønne Graben supports the proposed revision of the stratigraphy and leads to a new model. Previous interpreta-tions invoked a major uplift of the graben along a reverse fault at the eastern border of the Rønne Graben. In the new model, Late Cretaceous inversion across the Rønne Graben is associated withtilting of the graben during differential subsidence/uplift of the Skurup Platform and the Arnager Block, whereas reverse faulting was limited.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

24

Chiou, Shu-Fen, Jimmy Kuo, Tit-Yee Wong, Tung-Yung Fan, Kwee Siong Tew und Jong-Kang Liu. „Analysis of the coral associated bacterial community structures in healthy and diseased corals from off-shore of southern Taiwan“. Journal of Environmental Science and Health, Part B 45, Nr. 5 (04.06.2010): 408–15. http://dx.doi.org/10.1080/03601231003800032.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

25

Dempster, Tim, und Michael J. Kingsford. „Drifting objects as habitat for pelagic juvenile fish off New South Wales, Australia“. Marine and Freshwater Research 55, Nr. 7 (2004): 675. http://dx.doi.org/10.1071/mf04071.

Der volle Inhalt der Quelle

Annotation:

The importance of drifting objects to small juvenile pelagic fish was investigated off the coast of New South Wales, Australia. Distance-related and temporal patterns in the distribution of clumps of drifting algae were investigated with 5000 m2 transects at five distances from shore (0.1, 0.5, 1, 5 and 10 km), two to three times per season for 2 years. Juvenile fish associated with drift algae were collected. Clumps of algae, predominantly Sargassum spp., were most abundant in spring, which coincided with the highest abundance of alga-associated post-flexion juvenile fish. Drift algae were also most abundant close to shore, probably due to the proximity to source and the dominant onshore winds. Fish were quickly attracted to drifting artificial objects (fish aggregation device; FADs), although the magnitude of attraction varied greatly among days. The relative abundance of small fish in open waters available to colonise FADs and differing weather conditions may explain much of this variability. More fish colonised FADs with an odour source than unscented control FADs, indicating small fish may use chemical cues to locate drifting structures. We conclude that juvenile fish actively seek drifting objects as pre-settlement habitat, which may reduce predation and enhance settlement opportunities.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

26

Chavez, Arturo Gomez, Christian A. Mueller, Tobias Doernbach und Andreas Birk. „Underwater navigation using visual markers in the context of intervention missions“. International Journal of Advanced Robotic Systems 16, Nr. 2 (01.03.2019): 172988141983896. http://dx.doi.org/10.1177/1729881419838967.

Der volle Inhalt der Quelle

Annotation:

Intervention missions, that is, underwater manipulation tasks, for example, in the context of oil-&-gas production, require a high amount of precise, robust navigation. In this article, we describe the use of an advanced vision system suited for deep-sea operations, which in combination with artificial markers on target structures like oil-&-gas production-Christmas-trees significantly boosts navigation performance. The system is validated in two intensive field tests running off the shore of Marseille, France. In the experiments, a commercial remotely operated vehicle equipped with the system and a mock-up structure with an oil-&-gas production panel is used to evaluate the navigation performance.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

27

KAN, Katsushige, Kazuo ASO und Hitoshi DOKI. „A simple method for analizing multi-leg-structures. Study on the lateral vibration of the off-shore structure(3rd Report).“ Shigen-to-Sozai 106, Nr. 4 (1990): 167–72. http://dx.doi.org/10.2473/shigentosozai.106.167.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

28

di Lorenzo, Emilio, Simone Manzato, Bart Peeters und Herman van der Auweraer. „Virtual Structural Monitoring of Wind Turbines Using Operational Modal Analysis Techniques“. Key Engineering Materials 569-570 (Juli 2013): 523–30. http://dx.doi.org/10.4028/www.scientific.net/kem.569-570.523.

Der volle Inhalt der Quelle

Annotation:

Operational Modal Analysis (OMA), also known as output-only modal analysis, allows identifying modal parameters only by using the response measurements of the structures in operational conditions when the input forces cannot be measured. These information can then be used to improve numerical models in order to monitor the operating and structural conditions of the system. This is a critical aspect both for condition monitoring and maintenance of large wind turbines, particularly in the off-shore sector where operation and maintenance represent a high percentage of total costs. Although OMA is widely applied, the wind turbine case still remains an open issue. Numerical aeroelastic models could be used, once they have been validated, to introduce virtual damages to the structures in order to analyze the generated data. Results from such models can then be used as baseline to monitor the operating and structural condition of the machine.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

29

OLIVEIRA, Márcio Ulguim, Luciano Volcanoglo BIEHL, Jorge Luiz Braz MEDEIROS, César Antonio Oropesa AVELLANEDA, Carlos Otávio Damas MARTINS, José de SOUZA und Frederico SPORKET. „Manufacturing Against Corrosion: Increasing Materials Performance by the Combination of Cold Work and Heat Treatment for 6063 Aluminium Alloy“. Materials Science 26, Nr. 1 (08.11.2019): 30–33. http://dx.doi.org/10.5755/j01.ms.26.1.17683.

Der volle Inhalt der Quelle

Annotation:

Nowadays, the search for more reliable and less fuel consumable structures for off shore applications leads to the development of modern materials selection and manufacturing methodologies. In this sense, Aluminum alloys has increasing for structural application due to lightweight, weldability and corrosion performance. This research aims to evaluate the influence of manufacturing process of 6063 aluminum alloy on corrosion behavior in seawater medium. After the combination of heat treatment and cold work variation, the materials were analyzed by microstructural and mechanical tests. The sample also were submitted to Potentiodynamic polarization analysis. The results prove the applicability of cold work process in order to elevate corrosion performance of 6063 aluminum alloys. This can be a low cost and time consumable, alternative to increase materials performance.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

30

Rana, Fabio M., Maria Adamo, Guido Pasquariello, Giacomo De Carolis und Sandra Morelli. „LG-Mod: A Modified Local Gradient (LG) Method to Retrieve SAR Sea Surface Wind Directions in Marine Coastal Areas“. Journal of Sensors 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/9565208.

Der volle Inhalt der Quelle

Annotation:

This paper describes a novel SAR wind direction estimation method based on the computation of local gradients over quasi-linear and quasi-periodic structures detected by SAR imagery. The method relies upon the standard LG method for the part relevant to the computation of the local gradients. The novelty is that the dominant local wind direction and related accuracy are estimated using results derived from the Directional Statistics. The LG-Mod is validated against in situ coastal wind measurements provided by instrumented buoys with 63 ENVISAT ASAR images. Results show an overall agreement with RMSE values obtained for off-shore areas, but residual effects due to the complex phenomena occurring in the proximity of shoreline may degrade the performance when running in automated mode.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

31

Caruso, Maria Chiara, Carmine Pascale, Esteban Camacho und Liberato Ferrara. „Comparative environmental and social life cycle assessments of off-shore aquaculture rafts made in ultra-high performance concrete (UHPC)“. International Journal of Life Cycle Assessment 27, Nr. 2 (Februar 2022): 281–300. http://dx.doi.org/10.1007/s11367-021-02017-6.

Der volle Inhalt der Quelle

Annotation:

Abstract Purpose This paper aims to compare the environmental and social impacts of three types of rafts for mussel farming in Spain. These structures, traditionally made of wood, have a short lifespan and, because of their service conditions, require frequent maintenance in order to be fully operational. An innovative solution made with ultra-high performance concrete (UHPC) was developed in 2016 by RDC, being at the base of the pilots of the EU-funded project ReSHEALience (H2020-GA760824). Methods In order to quantify the environmental and social impacts generated by alternative solutions for the aquaculture raft, a life cycle approach has been used. The life cycle assessment methodology, according to ISO 14040 and ISO 14044 standards, has been used for the evaluation of the environmental impacts, while the social life cycle assessment (SLCA) methodology, according to the Guidelines for SLCA of Products and the social impact assessment method developed by Ciroth and Franze (2011), has been used for the evaluation of the social impacts: the same functional unit and the same stages of the life cycle to be included in the study has been set for the alternative solutions. Results and discussion Based on the LCA results, derived from the system boundary described in the “Goal and scope” section for the mussel aquaculture structures, the highest environmental impacts in the cradle-to-grave analysis are generated by the Traditional Raft with maintenance based on the periodic application of paints; the lowest environmental impacts are generated by the Traditional Raft with maintenance based on the progressive replacement of the damaged logs, while the Innovative Raft has an intermediate behavior in terms of environmental impact generation. Based on the S-LCA results, it can be stated that both the solutions generate high impacts; nevertheless, the Innovative solution has a slight lower impact than the Traditional solutions, which could be lowered if some precautions in the society policy are taken. Social hot-spots are identified in order to help reducing the overall social impacts. Conclusions In conclusion, it can be stated that, from both the environmental and social points of view, the Traditional Solutions for the aquaculture raft are the most “impactful,” especially when the maintenance is based on paint application. The use of innovative concretes allows to build longer lifespan rafts with minimum (or no) need of maintenance. Moreover, the behavior of new companies is more attentive to social aspects related to their activities and has a margin of improvement, when compared to traditional companies.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

32

Avedik, F., V. Renard, J. P. Allenou und B. Morvan. „“Single bubble” air‐gun array for deep exploration“. GEOPHYSICS 58, Nr. 3 (März 1993): 366–82. http://dx.doi.org/10.1190/1.1443420.

Der volle Inhalt der Quelle

Annotation:

Large tuned air‐gun arrays operated in off‐shore petroleum exploration are also used for deep penetration marine seismic reflection surveys conducted to define structures in the earth’s crust. Because of the attenuation of higher frequencies, the useful upper frequency limit of these records is usually about 50–60 Hz. The aim of this paper is to report on a method of seismic pulse generation that preferentially concentrates the air gun’s energy in the low range of the seismic frequency band by centering the output on the first “bubble pulse” instead of the initial (primary) pulse. Experimental results show that, due to the increased low‐frequency energy content of this “single bubble” pulse, air‐gun arrays considerably reduced both in size and volume can generate the necessary acoustic energy for deep seismic exploration.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

33

Bravo, L., M. Ramos, O. Astudillo, B. Dewitte und K. Goubanova. „Seasonal variability of the Ekman transport and pumping in the upwelling system off central-northern Chile (~ 30° S) based on a high-resolution atmospheric regional model (WRF)“. Ocean Science Discussions 12, Nr. 6 (08.12.2015): 3003–41. http://dx.doi.org/10.5194/osd-12-3003-2015.

Der volle Inhalt der Quelle

Annotation:

Abstract. Two physical mechanisms can contribute to coastal upwelling, offshore Ekman transport and Ekman pumping due to the cyclonic wind stress curl, mainly caused by the abrupt decrease in wind stress (drop-off) in a cross-shore band of 100 km. This wind drop-off is thought to be an ubiquitous feature in coastal upwelling systems and to regulate the relative contribution of both mechanisms. It has been poorly studied along the central-northern Chile region because of the lack in wind measurements along the shoreline and of the relatively low-resolution of the available atmospheric Reanalysis. Here, the seasonal variability in Ekman transport, Ekman pumping and their relative contribution to total upwelling along the central-northern Chile region (~ 30° S) is evaluated from a high-resolution atmospheric model simulation. As a first step, the simulation is validated from satellite observations, which indicates a proper representation of the spatial and temporal variability of the wind along the coast by the model. The model outputs are then used to document the fine scale structures in the wind stress and wind curl in relation with the topographic features along the coast (headlands and embayments). Both wind stress and wind curl had a clear seasonal variability with a marked semiannual component. Alongshore wind stress maximum peak occurred in spring, second increase was in fall and minimum in winter. When a threshold of −3 x 10−5 s−1 for the across-shore wind curl was considered to define the region from which the winds decrease on-shoreward, the wind drop-off length scale varied between 8 and 45 km. The relative contribution of Ekman transport and Ekman pumping to the vertical transport along the coast, considering the estimated wind drop-off length, indicated meridional alternation between both mechanisms, modulated by orography and the intricate coastline. Roughly, coastal divergence predominated in areas with low orography and headlands. Ekman pumping was higher in regions with high orography and the presence of embayments along the coast. In the study region, the vertical transport induced by coastal divergence and Ekman pumping represented 60 and 40 % of the total upwelling transport, respectively. The potential role of Ekman pumping on the spatial structure of sea surface temperature is also discussed.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

34

Tripoli, Gregory J. „Numerical Study of the 10 January 1998 Lake-Effect Bands Observed during Lake-ICE“. Journal of the Atmospheric Sciences 62, Nr. 9 (01.09.2005): 3232–49. http://dx.doi.org/10.1175/jas3462.1.

Der volle Inhalt der Quelle

Annotation:

Abstract This paper presents the results of a series of idealized cloud resolving simulations of the evolution of moist roll convection observed as part of the Lake-Induced Convection Experiment (Lake-ICE) that took place during the 1997/98 winter over central Lake Michigan. Satellite and radar observations of the roll convection depict striking linear rolls stretching from 10 km off the western shore of the lake, across to the eastern shore, and then continuing across Michigan. The spacing of the primary rolls was observed to be 6 km, giving a ratio of spacing to depth of about 5:1, which is consistent with theory. In addition, a longer wavelength (13 km) of stationary banding was observed parallel to the shoreline. In an earlier study of this case, multiply nested simulations of the convective rolls based on real data variable initialization were successful in producing banded structures with similar spacing and location over the water to those observed using fine grid resolution of about 500 m. Unfortunately, the initial locations of simulated bands were organized primarily by numerical effects of grid interpolation. This suggested that the spacing of the bands was robust, but that their initial location was highly sensitive to subtle systematic forcings. In this paper, a set of idealized model experiments, designed to isolate the role that physically realistic local forcing plays in the organization of the rolls, was performed. Because externally generated upstream turbulence was suppressed in these tests so as not to bias the result, the generation of rolls was delayed until 20–30 km downwind of the observed location and the location simulated in the previous grid nesting experiments. It was shown that the subtle effects of the shoreline geometry were sufficient to spawn a near-surface streamwise vorticity that became the primary seed for roll development at the most efficient mode of roll convection. These results suggest that previous structures evolved in the upstream shear-driven land-based mixed layer were likely also important in determining where the nonlocal overturning was first triggered. It is not clear from these results whether the shear-driven structures that evolved over the land also played a significant role in organizing the structural geometry of the lake rolls. Results also suggested that the shore parallel bands were a robust feature of the atmospheric structure resulting from resonant gravity wave trapping in the frontal layer.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

35

Kasprzak, R. A., und W. S. Perret. „USE OF OIL AND GAS PLATFORMS AS HABITAT IN LOUISIANA'S ARTIFICIAL REEF PROGRAM“. APPEA Journal 36, Nr. 1 (1996): 681. http://dx.doi.org/10.1071/aj95048.

Der volle Inhalt der Quelle

Annotation:

Louisiana's offshore oil and gas industry began in 1947 when the first well was drilled out of sight of land south of Terrebonne Parish. Today over 3,700 offshore oil and gas platforms have been installed, supplying 25 per cent of the United States' production of natural gas and 12.5 per cent of its oil. In addition to meeting the world's energy needs, these structures also form one of the world's most extensive defacto artificial reef systems. However, federal regulations require that these structures be removed within 1 year after the lease is terminated. Disposal of obsolete offshore oil and gas structures is not only a net financial liability for private industry but can be a public loss of productive marine habitat. In 1986 the Louisiana Fishing Enhancement Act was signed into law, in response to the National Fishing Enhancement Act, creating the Louisiana Artificial Reef Program. This program was designed to take advantage of fishing habitat opportunities offered by these obsolete platforms. Since the program's inception 22 reef sites, utilising the components (jackets and decks) of 58 obsolete platforms, have been created off Louisiana's coast. The use of obsolete oil and gas platforms in Louisiana has proved to be highly successful. Their large numbers, design, longevity, and stability have provided a number of advantages over the use of traditional artificial reef materials. The participating companies also save money by converting the structure into a reef rather than abandoning it onshore; these companies are required to donate a portion of the savings to the state to run the artificial reef program. One disadvantage, however, is that the large size of these platforms restricts the distance to shore where they can be sited. To achieve the minimum clearance of 16 m over a submerged structure, as required by the Coast Guard regulations, the platforms must be placed in waters deeper than 30 m. Waters of this depth are found between 22 km and 115 km from shore on Louisiana's gently sloping continental shelf, making them almost inaccessible to many anglers. Funds generated by the program, however, can be used to develop reefs closer to shore if alternative low profile materials are used. Due to high maintenance costs of both the structure and aids to navigation, the increased liability exposure and the undetermined cost of removing the structure once it becomes a hazard to public safety and navigation, leaving the structures standing in place has thus far proved not to be a viable option in Louisiana.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

36

Cleary, Joe. „The English Department as Imperial Commonwealth, or The Global Past and Global Future of English Studies“. boundary 2 48, Nr. 1 (01.02.2021): 139–76. http://dx.doi.org/10.1215/01903659-8821461.

Der volle Inhalt der Quelle

Annotation:

Though canons and faculty have greatly diversified in recent decades, English departments around the world fundamentally prioritize English and American literatures. To this extent, they resemble the Anglo-American imperial commonwealths that some toward the end of the nineteenth century advocated for in order to stave off the decline of the British Empire and to shore up a permanent Anglo-American supremacy against all threats. Still, as the English language becomes “global,” English departments today founder for a variety of reasons and convey a persistent sense of crisis. Has the time come radically to decolonize the English department, not only at the level of curriculum but also in terms of its basic organizational structures to facilitate the study of anglophone literatures now planetary in reach? If so, how might this best be achieved in the British and American core countries and also in the more peripheral regions of Anglophonia?

APA, Harvard, Vancouver, ISO und andere Zitierweisen

37

Deendayal, R., T. G. Sitharam und K. Muthukkumaran. „Effect of Earthquake on a Single Pile Located in Sloping Ground“. International Journal of Geotechnical Earthquake Engineering 7, Nr. 1 (Januar 2016): 57–72. http://dx.doi.org/10.4018/ijgee.2016010104.

Der volle Inhalt der Quelle

Annotation:

Piles are often constructed on natural slope such as sea bed slope in off-shore structures. When piles are constructed on sloping ground, the behaviour of piles under earthquake loading is different from the piles on horizontal ground surface. The dynamic response of a pile subjected to external excitation is a complex phenomenon resulting from the interactions between the pile and the surrounding soil. In the present study, a finite element analysis of a single field pile located on sloping ground was carried out. A single pile of length 30m with embedment length to diameter ratios (L/D) 20, 25 and 30 was located on a crest of soft clay of slopes 1V:1H and 1V:5H, and subjected to dynamic earthquake loading (California Earthquake,1990). From the study, the behaviour of acceleration with time, lateral displacement and bending moment behavior along the pile shaft was studied.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

38

KOMAROVA, NATALIA L., und ALAN C. NEWELL. „Nonlinear dynamics of sand banks and sand waves“. Journal of Fluid Mechanics 415 (25.07.2000): 285–321. http://dx.doi.org/10.1017/s0022112000008855.

Der volle Inhalt der Quelle

Annotation:

Sand banks and sand waves are two types of sand structures that are commonly observed on an off-shore sea bed. We describe the formation of these features using the equations of the fluid motion coupled with the mass conservation law for the sediment transport. The bottom features are a result of an instability due to tide–bottom interactions. There are at least two mechanisms responsible for the growth of sand banks and sand waves. One is linear instability, and the other is nonlinear coupling between long sand banks and short sand waves. One novel feature of this work is the suggestion that the latter is more important for the generation of sand banks. We derive nonlinear amplitude equations governing the coupled dynamics of sand waves and sand banks. Based on these equations, we estimate characteristic features for sand banks and find that the estimates are consistent with measurements.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

39

Elías, Matías W., Fabio I. Zyserman, Marina Rosas-Carbajal und María Constanza Manassero. „Three-dimensional modelling of controlled source electro-magnetic surveys using non-conforming finite element methods“. Geophysical Journal International 229, Nr. 2 (28.12.2021): 1133–51. http://dx.doi.org/10.1093/gji/ggab524.

Der volle Inhalt der Quelle

Annotation:

SUMMARY The controlled source electro-magnetic (CSEM) method is increasingly used for in-land and off-shore subsurface characterization. Given its complex dependence between data and the parameters of interest, there is a crucial need for performant numerical algorithms that can simulate the CSEM response of 3-D geological structures. Here, we present two finite element (FE) algorithms for simulating the CSEM response in 3-D media with isotropic conductivity. A primary/secondary field approach is used to avoid the singularity introduced by the source. The primary field is computed semi-analytically for a horizontally layered model and different sources. The secondary field is obtained by discretizing the diffusive frequency-domain Maxwell’s equations with non-conforming FE. The two numerical algorithms are specifically designed to work on distributed-memory computers: (1) an iterative procedure with domain decomposition and (2) a direct and global algorithm. We evaluate their performance by computing their speed up on parallel processors, and solving problems with realistic conductivity structures. We also compare the accuracy of the solutions with published results on canonical models. The results shown here demonstrate the functionality of the two methodologies presented for specific cases when computing 3-D CSEM solutions.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

40

Bravo, Luis, Marcel Ramos, Orlando Astudillo, Boris Dewitte und Katerina Goubanova. „Seasonal variability of the Ekman transport and pumping in the upwelling system off central-northern Chile (∼ 30° S) based on a high-resolution atmospheric regional model (WRF)“. Ocean Science 12, Nr. 5 (08.09.2016): 1049–65. http://dx.doi.org/10.5194/os-12-1049-2016.

Der volle Inhalt der Quelle

Annotation:

Abstract. Two physical mechanisms can contribute to coastal upwelling in eastern boundary current systems: offshore Ekman transport due to the predominant alongshore wind stress and Ekman pumping due to the cyclonic wind stress curl, mainly caused by the abrupt decrease in wind stress (drop-off) in a cross-shore band of 100 km. This wind drop-off is thought to be an ubiquitous feature in coastal upwelling systems and to regulate the relative contribution of both mechanisms. It has been poorly studied along the central-northern Chile region because of the lack in wind measurements along the shoreline and of the relatively low resolution of the available atmospheric reanalysis. Here, the seasonal variability in Ekman transport, Ekman pumping and their relative contribution to total upwelling along the central-northern Chile region (∼ 30° S) is evaluated from a high-resolution atmospheric model simulation. As a first step, the simulation is validated from satellite observations, which indicates a realistic representation of the spatial and temporal variability of the wind along the coast by the model. The model outputs are then used to document the fine-scale structures in the wind stress and wind curl in relation to the topographic features along the coast (headlands and embayments). Both wind stress and wind curl had a clear seasonal variability with annual and semiannual components. Alongshore wind stress maximum peak occurred in spring, second increase was in fall and minimum in winter. When a threshold of −3 × 10−5 s−1 for the across-shore gradient of alongshore wind was considered to define the region from which the winds decrease toward the coast, the wind drop-off length scale varied between 8 and 45 km. The relative contribution of the coastal divergence and Ekman pumping to the vertical transport along the coast, considering the estimated wind drop-off length, indicated meridional alternation between both mechanisms, modulated by orography and the intricate coastline. Roughly, coastal divergence predominated in areas with low orography and headlands. Ekman pumping was higher in regions with high orography and the presence of embayments along the coast. In the study region, the vertical transport induced by coastal divergence and Ekman pumping represented 60 and 40 % of the total upwelling transport, respectively. The potential role of Ekman pumping on the spatial structure of sea surface temperature is also discussed.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

41

Nagano, Akira, Takuya Hasegawa, Keisuke Ariyoshi und Hiroyuki Matsumoto. „Interannual Bottom-Intensified Current Thickening Observed on the Continental Slope Off the Southeastern Coast of Hokkaido, Japan“. Fluids 7, Nr. 2 (19.02.2022): 84. http://dx.doi.org/10.3390/fluids7020084.

Der volle Inhalt der Quelle

Annotation:

By rotary empirical orthogonal function and coastal-trapped wave mode analyses, we analyzed current velocity data, collected from 2001 to 2016. The data were obtained by an acoustic Doppler current profiler, deployed upward at a location of 41°39.909′ N, 144°20.695′ E, on a 2630-m deep continental slope seabed off the southeastern coast of Hokkaido, Japan. The results indicate that the current intensifies toward the bottom and is directed nearly toward the shore, reaching an average speed of ~2.5 cm s−1 just above the bottom. The thickness of the along-slope northward component of the bottom-intensified current varied within the range of 50–350 m. We found that the current thickness change was caused by oceanic barotropic disturbances, produced by the intensification of the Aleutian Low, largely related to the El Niño–Southern Oscillation and modified through the excitation of bottom-trapped modes of coastal-trapped waves. This finding improves the prediction accuracy of the the bottom-intensified current change, being beneficial for suspended sediment studies, construction and maintenance of marine structures, planning of deep drilling, and so on.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

42

Sirajudeen, Rahima Shabeen, und Alagusundaramoorthy P. „GFRP Stiffened Plate with Square Cutout under Axial and Out-of-Plane Load“. Polymers 13, Nr. 8 (07.04.2021): 1185. http://dx.doi.org/10.3390/polym13081185.

Der volle Inhalt der Quelle

Annotation:

The high-strength-to-weight ratio and corrosion resistance properties of glass-fiber-reinforced polymer (GFRP) composites makes them potentially well-suited for application in ship structures, bridges and off-shore oil platforms. These structures are often formed by stiffened plates and are subjected to axial load and out-of-plane load. Cutouts and openings are provided in the plates for access and maintenance. The main objective of this study was to examine the buckling behavior of GFRP-stiffened composite plates with square cutouts under a combination of axial and out-of-plane load up to failure. Four blade-stiffened composite plates without a cutout and four with square cutout were fabricated with stiffeners as a continuous layup of the flange plate using glass fiber and epoxy resin. The initial geometric imperfections were measured, and plate imperfections (Δx), stiffener imperfections (Δsy) and overall imperfections (Δsx) were calculated from the measurements. All fabricated-stiffened composite plates were tested up to failure. The finite element model was developed in ANSYS software and validated with the experimental results. It was observed that GFRP-stiffened composite plates failed by stiffener compression/stiffener tension mode of failure. The presence of out-of-plane loads and cutouts reduced the axial load carrying capacity of the stiffened composite plates.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

43

Dmitrenko, Igor A., Sergey A. Kirillov, Bert Rudels, David G. Babb, Leif Toudal Pedersen, Søren Rysgaard, Yngve Kristoffersen und David G. Barber. „Arctic Ocean outflow and glacier–ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)“. Ocean Science 13, Nr. 6 (11.12.2017): 1045–60. http://dx.doi.org/10.5194/os-13-1045-2017.

Der volle Inhalt der Quelle

Annotation:

Abstract. The first-ever conductivity–temperature–depth (CTD) observations on the Wandel Sea shelf in northeastern Greenland were collected in April–May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014–2015 drift. The CTD profiles are used to reveal the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature–salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean–glacier interaction. Our observations of Pacific water are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different thermohaline structures indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through the western Fram Strait.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

44

Lovy, J., NL Lewis, SE Friend, KW Able, MJ Shaw, GS Hinks und PJ Clarke. „Host, seasonal and habitat influences on incidence of Lernaeenicus radiatus (Copepoda: Pennellidae) in the mid-Atlantic Bight“. Marine Ecology Progress Series 642 (28.05.2020): 83–101. http://dx.doi.org/10.3354/meps13326.

Der volle Inhalt der Quelle

Annotation:

Lernaeenicus radiatus is a pennellid copepod with a 2-host life cycle that exhibits high host-specificity to their first host, black sea bass Centropristis striata. This parasite was prevalent in the gills of black sea bass juveniles and adults along the coast of New Jersey, USA, April to December 2019. Parasite incidence was high in the summer and fall in near-shore areas and dropped significantly in fish from deep waters further off-shore in December. Heavy infections of L. radiatus occurred in gills of adult black sea bass inhabiting reef-associated structures, in which parasite incidence rate was 2-3.7 times higher than in non-structure habitat. Less host-specificity occurred in second hosts which support female metamorphosis. In total, 7 fish species were confirmed as second hosts, with the most common being Atlantic menhaden Brevoortia tyrannus and bay anchovy Anchoa mitchilli. Incidence of L. radiatus depends on host abundance and habitats that support interactions of the preferred fish hosts, which may explain the heavy infections in reef habitats. The L. radiatus anchor process in metamorphosed females was highly polymorphic, depending on tissue tropism. Parasite length varied considerably, with neck and trunk measurements of L. radiatus from adult menhaden being 2-4 times larger than those from smaller host species. Mitochondrial cytochrome oxidase c subunit I (COI) sequences demonstrated all parasites to be L. radiatus, with sequence divergence limited to 0.3%. These findings show that morphology of the metamorphosed females has poor taxonomic value, and polymorphisms instead are related to attachment site and host characteristics.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

45

Cadoni, Ezio, Matteo Dotta und Daniele Forni. „Modern high strength steels under high strain-rate regimes“. EPJ Web of Conferences 250 (2021): 05013. http://dx.doi.org/10.1051/epjconf/202125005013.

Der volle Inhalt der Quelle

Annotation:

In order to properly design critical infrastructures and buildings in steel (bridges, high-rise building, off-shore, cranes, etc.), certain requirements concerning to mechanical resistance and robustness under exceptional actions have to be carefully fulfilled. An acceptable level of safety must be assured to avoid human loss, environmental pollution and material damage. These structures can be subjected to severe accidental loading such as blast or impact. In this context it is fundamental to adequately know the behaviour of structural steel under high strain rate. Modern high strength steels are quenched and selftempered steels. These steels have several layers with differentiated microstructures (martensitic in the cortical part and ferritic in the core). The behaviour of the single layer at high strain rate regimes have to be accurately studied. The paper collects and discusses the tensile results at high strain rate obtained on samples of homogeneous layers of S690QL and S960QL steels. Finally, the characterisation of the single layers has been used in order to analyse the results obtained in large specimen obtained from slabs 12mm thick.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

46

Małecki, Józef. „Fuzzy Track-Keeping Steering Design for a Precise Control of the Ship“. Solid State Phenomena 196 (Februar 2013): 140–47. http://dx.doi.org/10.4028/www.scientific.net/ssp.196.140.

Der volle Inhalt der Quelle

Annotation:

In this paper we design the fuzzy logic autopilot to precise control and a track-keeping control of the ship. Precise control of ship has known an increasing interest in the last years. The main benefits of usage of autopilot for control of ship can be removing a man from the dangers of the undersea environment and reduction in cost of exploration of deep seas. Currently, it is common to use the special ship to accomplish missions as the inspection of coastal and off-shore structures, cable maintenance, as well as hydrographical surveys. In the military field they are employed in such tasks as surveillance, intelligence gathering, torpedo recovery and mine counter measures. Hence, a problem of its ability to move along a reference path and keep a desired orientation is regarded. A non-linear mathematical model describes the vehicle’s dynamics. Command signals are generated by an autopilot with fuzzy control law implemented. Some results of computer simulations are provided to demonstrate effectiveness, correctness and usefulness of the approach.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

47

De Leo, Francesco, Giovanni Besio und Lorenzo Mentaschi. „Trends and variability of ocean waves under RCP8.5 emission scenario in the Mediterranean Sea“. Ocean Dynamics 71, Nr. 1 (20.11.2020): 97–117. http://dx.doi.org/10.1007/s10236-020-01419-8.

Der volle Inhalt der Quelle

Annotation:

AbstractWind-generated ocean waves are key inputs for several studies and applications, both near the coast (coastal vulnerability assessment, coastal structures design, harbor operativity) and off-shore (a.o. oil and gas production, ship routes, and navigation safety). As such, the evaluation of trends in future wave climate is fundamental for the development of efficient policies in the framework of climate change adaptation and mitigation measures. This study focuses on the Mediterranean Sea, an area of primary interest, since it plays a crucial role in the worldwide maritime transport and it is highly populated along all its coasts. We perform an analysis of wave climate changes using an ensemble of 7 models under emission scenario RCP8.5, over the entire Mediterranean basin. Future projections of wave climate and their variability are analyzed taking into account annual statistics of wave parameters, such as significant wave height, mean period, and mean direction. The results show, on average, a decreasing trend of significant wave height and mean period, while the wave directions may be characterized by a slight eastward shift.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

48

Lemartinel, Antoine, Mickaël Castro, Olivier Fouché, Julio-César De Luca und Jean-François Feller. „Strain Mapping and Damage Tracking in Carbon Fiber Reinforced Epoxy Composites during Dynamic Bending Until Fracture with Quantum Resistive Sensors in Array“. Journal of Composites Science 5, Nr. 2 (20.02.2021): 60. http://dx.doi.org/10.3390/jcs5020060.

Der volle Inhalt der Quelle

Annotation:

The sustained development of wind energies requires a dramatic rising of turbine blade size especially for their off-shore implantation, which requires as well composite materials with higher performances. In this context, the monitoring of the health of these structures appears essential to decrease maintenance costs, and produce a cheaper kwh. Thus, the input of quantum resistive sensors (QRS) arrays, to monitor the strain gradient in area of interest and anticipate damage in the core of composite structures, without compromising their mechanical properties, sounds promising. QRS are nanostructured strain and damage sensors, transducing strain at the nanoscale into a macroscopic resistive signal for a consumption of only some µW. QRS can be positioned on the surface or in the core of the composite material between plies, and this homogeneously as they are made of the same resin as the composite. The embedded QRS had a gauge factor of 3, which was found more than enough to follow the strain from 0.01% to 1.4% at the final failure. The spatial deployment of four QRS in array made possible for the first time the experimental visualization of a strain field comparable to the numerical simulation. QRS proved also to be able to memorize damage accumulation within the sample and thus could be used to attest the mechanical history of composites.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

49

Bamonte, Patrick, und Pietro Gambarova. „Properties of Concrete Subjected to Extreme Thermal Conditions“. Journal of Structural Fire Engineering 5, Nr. 1 (01.03.2014): 47–62. http://dx.doi.org/10.1260/2040-2317.5.1.47.

Der volle Inhalt der Quelle

Annotation:

Durability, high-temperature resistance, impact and blast resilience, radiation-shielding properties, irradiation endurance and - of course - good mechanical properties are required of the cementitious composites to be used in a variety of high-performance structures. Among these, tall buildings, road and railway tunnels, off-shore platforms, gasification plants, wind and solar mills for the production of "clean" energy should be mentioned, as well as nuclear power plants, and radioactive- and hazardous-waste repositories. Hence, understanding, measuring and modelling concrete behavior under extreme environmental conditions is instrumental in making concrete structures safer and more efficient. To this end, the hot and residual properties associated with the exposure to high temperature, fire and thermal shock are treated in this paper. Reference is made to ordinary vibrated concrete (Normal-Strength Concrete - NSC), as well as to a number of innovative cementitious composites, such as Fiber-Reinforced Concrete - FRC, High-Performance/High-Strength Concrete - HPC/HSC, Ultra High-Performance/Very High-Strength Concrete - UHPC /VHSC, Self-Compacting/Consolidating Concrete - SCC, Light-Weight Concrete - LWC, shotcrete and high-strength mortars. It is shown that these materials can be "tailored" according to a variety of requirements and functions, even if several aspects of their behavior (like spalling in fire and long-term mechanical properties under sustained high temperature) are still open to investigation.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

50

Abramovitz, T., und H. Thybo. „Pre-Zechstein structures around the MONA LISA deep seismic lines in the southern Horn Graben area“. Bulletin of the Geological Society of Denmark 45 (30.01.1999): 99–116. http://dx.doi.org/10.37570/bgsd-1998-45-10.

Der volle Inhalt der Quelle

Annotation:

Seismic reflection data from the Horn Graben area in the southeastern part of the North Sea, off-shore Denmark, have been interpreted to illustrate the upper crustal structures around the MONA LISA deep seismic lines. The study area comprises the southern Horn Graben area and the eastern part of East North Sea High, where the Caledonian collision suture between Baltica and Eastern Avalonia bends such that the strike direction changes from ESE in the south to NNW in the north. Integrated interpretation of normal-incidence reflection data and wide-angle refraction data reveals substantial occurrences of lower and upper Palaeozoic strata in the area, thickest below the Horn Graben. This may indicate that Horn Graben developed as a graben structure during late Palaeozoic in the former Caledonian foredeep. On the northern and eastern parts of the MONA LISA deep seismic reflection lines 1 and 3, the main E- dipping boundary fault of the southern Horn Graben segment appears to be listric at depth with a sub-horizon-tal detachment at the top of the reflective lower crust. We have mapped the lateral extent of the lower Permian, volcanic Rotliegend reflector in the study area on the basis of seismic lines from the RTD-81 survey. Dipping reflections observed in the sedimentary strata below the Rotliegend reflector are interpreted as Cal-edonian structures generated by folding and deformation in Lower Palaeozoic Baltica shelf sediments in the Caledonian foreland basin. A sequence of S- and W-dipping reflections above 4 s twt are interpreted as preserved Caledonian thrusts in the upper crustal frontal part of the SW-dipping Caledonian Deformation Front.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Zeitschriftenartikel zum Thema „Off-shore structures“

Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an