scholarly journals Morphological divergence between three Arctic charr morphs – the significance of the deep‐water environment

2015 ◽  
Vol 5 (15) ◽  
pp. 3114-3129 ◽  
Author(s):  
Sigrid Skoglund ◽  
Anna Siwertsson ◽  
Per‐Arne Amundsen ◽  
Rune Knudsen
Keyword(s):  
Deep Water ◽  
Arctic Charr ◽  
Water Environment ◽  
Morphological Divergence

scholarly journals Introduction of Mysis relicta (Mysida) reduces niche segregation between deep-water Arctic charr morphs

Hydrobiologia ◽  
2019 ◽  
Vol 840 (1) ◽  
pp. 245-260 ◽  
Author(s):  
Rune Knudsen ◽  
Antti P. Eloranta ◽  
Anna Siwertsson ◽  
Rachel A. Paterson ◽  
Michael Power ◽  
...  
Keyword(s):  
Deep Water ◽  
Arctic Charr ◽  
Niche Segregation ◽  
Mysis Relicta

scholarly journals A Depth-Bistatic Bottom Reverberation Model and Comparison with Data from an Active Triplet Towed Array Experiment

2020 ◽  
Vol 10 (9) ◽  
pp. 3080
Author(s):  
Youngcheol Jung ◽  
Woojae Seong ◽  
Keunhwa Lee ◽  
Seongil Kim
Keyword(s):  
Time Series ◽  
Deep Water ◽  
Water Environment ◽  
Ray Theory ◽  
Reverberation Time ◽  
Environment Model ◽  
Line Array ◽  
Model Predictions ◽  
Towed Array ◽  
Good Agreement

In this paper, a depth-bistatic bottom reverberation model that employs the ray theory is presented. The model can be applied to an active towed array in the ocean. The reverberation time series are modeled under the depth-bistatic assumption and their Doppler shift is calculated based on the actual source–receiver geometry. This model can handle N × 2D range-dependent bathymetry, the geometry of a triplet array, and the Doppler motion of the source, targets, and receiver. The model predictions are compared with the mid-frequency reverberation data measured by an active triplet towed array during August 2015 in the East Sea, Korea. These data are collected with a variable depth source at mid-frequency and the triplet line array in a deep-water environment. Model predictions of the beam time series and its spectrogram are in good agreement with the measurement. In particular, we discuss the effects of the source and receiver depths on the reverberation in deep water observed in both the measured and modeled results.

Geoacoustic inversion from moving ship of opportunity in deep‐water environment

2004 ◽  
Vol 115 (5) ◽  
pp. 2408-2408 ◽  
Author(s):  
David P. Knobles ◽  
Tim Scoggins ◽  
Jack Shooter
Keyword(s):  
Deep Water ◽  
Water Environment ◽  
Geoacoustic Inversion

Slope-instability processes caused by salt movements in a complex deep-water environment, Bryant Canyon area, northwest Gulf of Mexico

AAPG Bulletin ◽  
2004 ◽  
Vol 88 (6) ◽  
pp. 801-823 ◽  
Author(s):  
Efthymios K. Tripsanas ◽  
William R. Bryant ◽  
Brett A. Phaneuf
Keyword(s):  
Gulf Of Mexico ◽  
Deep Water ◽  
Water Environment ◽  
Slope Instability

Cathodic protection criteria of low alloy steel in simulated deep water environment

2020 ◽  
Vol 67 (4) ◽  
pp. 427-434
Author(s):  
Haijing Sun ◽  
Weihai Xue ◽  
Jiaxin Xu ◽  
Guoliang Chen ◽  
Jie Sun
Keyword(s):  
Shallow Water ◽  
Alloy Steel ◽  
Deep Water ◽  
Cathodic Protection ◽  
Water Environment ◽  
Deep Ocean ◽  
Low Alloy Steel ◽  
Content Type ◽  
Offshore Industry ◽  
Protection Potential

Purpose The purpose of this work is to provide theoretical guidance and experimental analysis for optimized cathodic protection (CP) design of low alloy steel in deep water environments. Design/methodology/approach In the present study, the CP criteria of 10Ni5CrMoV low alloy steel were investigated in a simulated deep water environment (350 m) regarding the theoretical protection potential and measured protection potential. The influences of hydrostatic pressure (HP) and temperature were also discussed in detail. The theoretical protection potential was analyzed with the Nernst equation, and the measured minimum protection potential was derived by extrapolating the Tafel portion of anodic polarization curves. Findings The results indicate that the minimum protection potential of low alloy steel shifts to a positive value in a deep-ocean environment. This can be attributed to the combined effects of HP and the temperature. Moreover, the temperature has a stronger influence compared with HP. The results suggest that the CP potential criteria used in shallow water are still applicable in the deep ocean, which is further confirmed through the SEM and x-ray diffraction analysis of the corrosion products resulted from the potentiostatic cathodic polarization experiments at −0.85 VCSE. Originality/value In recent decades, successful applications of CP for long-term corrosion protection of the steel components applied at a subsea level have enabled the offshore industry to develop reliable and optimized CP systems for shallow water. However, differences in the seawater environment at greater depths have raised concerns regarding the applicability of the existing CP design for deeper water environments. Hence, this research focuses on the CP criteria of low alloy steel in simulated deep water environment concerning the theoretical protection potential and measured protection potential. The influences of HP and temperature were also discussed.

scholarly journals Prior Analysis in Determination of TI Anisotropy Type through Well-Based Modelling: A Case Study on the Deep Water Environment

2021 ◽  
Vol 873 (1) ◽  
pp. 012102
Author(s):  
Madaniya Oktariena ◽  
Wahyu Triyoso ◽  
Fatkhan Fatkhan ◽  
Sigit Sukmono ◽  
Erlangga Septama ◽  
...  
Keyword(s):  
Wave Velocity ◽  
Deep Water ◽  
Initial Conditions ◽  
Transverse Isotropy ◽  
Water Environment ◽  
Horizontal Stress ◽  
P Wave ◽  
S Wave ◽  
Geomechanical Analysis ◽  
Vertical Transverse Isotropy

Abstract The existence of anisotropy phenomena in the subsurface will affect the image quality of seismic data. Hence a prior knowledge of the type of anisotropy is quite essential, especially when dealing with deep water targets. The preliminary result of the anisotropy of the well-based modelling in deep water exploration and development is discussed in this study. Anisotropy types are modelled for Vertical Transverse Isotropy (VTI) and Horizontal Transverse Isotropy (HTI) based on Thomsen Parameters of ε and γ. The parameters are obtained from DSI Logging paired with reference δ value for modelling. Three initial conditions are then analysed. The first assumption is isotropic, in which the P-Wave Velocity, S-Wave Velocity, and Density Log modelled at their in-situ condition. The second and third assumptions are anisotropy models that are VTI and HTI. In terms of HTI, the result shows that the model of CDP Gather in the offset domain has a weak distortion in Amplitude Variation with Azimuth (AVAz). However, another finding shows a relatively strong hockey effect in far offset, which indicates that the target level is a VTI dominated type. It is supported by the geomechanical analysis result in which vertical stress acts as the maximum principal axis while horizontal stress is close to isotropic one. To sum up, this prior anisotropy knowledge obtained based on this study could guide the efficiency guidance in exploring the deep water environment.

Computational Prediction of Electric Fields in Shallow Water Testing Environment

2009 ◽  
Author(s):  
Stephanie A. Wimmer ◽  
Virginia G. DeGiorgi ◽  
Elizabeth A. Hogan
Keyword(s):  
Shallow Water ◽  
Electric Fields ◽  
Deep Water ◽  
Cathodic Protection ◽  
Water Environment ◽  
Computational Prediction ◽  
Water Tank ◽  
Testing Environment ◽  
Field Environment ◽  
Cathodic Protection System

There has been an increased need for understanding of how ship’s cathodic protection systems work in shallow water environment. This is a result of the evolving role of the US Navy. The existing cathodic protection system design process relies on experimental processes. This paper investigates a proposed modification to a deep water experimental facility to allow for measurements of electrical fields, a pertinent design measurement, in shallow water conditions. The modifications involve the insertion of a false bottom in the existing deep water tank. The work presented here are a series of computational studies that establish that the insertion of a false bottom would provide an electric field environment that is equivalent to shallow water for the depths considered.

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