EFFECTS OF LONG-TERM DEEP-SEA IMMERSION ON THE IMPLOSION AND EXPLOSION OF HOLLOW COMPOSITE CYLINDERS

2021 ◽  
Author(s):  
◽  
Tyler Chu
Keyword(s):  
Deep Sea ◽  
Composite Cylinders

Composite Cylinders for Deep Sea Applications: An Overview

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Peter Davies ◽  
Dominique Choqueuse ◽  
Benoît Bigourdan ◽  
Pierre Chauchot
Keyword(s):  
Test Performance ◽  
Deep Sea ◽  
Impact Damage ◽  
Pressure Vessels ◽  
Thick Wall ◽  
Matrix Composites ◽  
Thermoplastic Matrix ◽  
Long Term Behavior ◽  
Composite Cylinders

In order to develop the knowledge base necessary to design deep sea pressure vessels, it is essential to understand the full chain from design and manufacturing through nondestructive testing (NDT) and characterization to long-term behavior under hydrostatic pressure. This paper describes results from European and national research programs focusing on the use of composites for underwater applications over the last 20 years. Initial tests on small glass/epoxy cylinders were followed by large demonstration projects on carbon/epoxy cylinders with implosion pressures of up to 600 bar, corresponding to 6000 m depth. Numerical modeling has enabled end closures design to be optimized for test performance. Thin and thick wall cylinders have been tested under quasi-static, and long-term loading. Both thermosetting and thermoplastic matrix composites have been tested to failure, and the influence of defects and impact damage on implosion pressure has been studied. These deep sea exploitation and exploration studies were performed for oceanographic, military, and offshore applications, and extensive data are available. The aim of this paper is to indicate existing results, particularly from European projects, in order to avoid costly repetition.

scholarly journals Contributions to Management Strategies in the NE Atlantic Regarding the Life History and Population Structure of a Key Deep-Sea Fish (Mora moro)

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 522
Author(s):  
Régis Santos ◽  
Wendell Medeiros-Leal ◽  
Osman Crespo ◽  
Ana Novoa-Pabon ◽  
Mário Pinho
Keyword(s):  
Population Structure ◽  
Life History ◽  
Deep Sea ◽  
Management Strategies ◽  
Size Composition ◽  
Large Size ◽  
The Common ◽  
Fishing Impacts ◽  
Sea Fish

With the commercial fishery expansion to deeper waters, some vulnerable deep-sea species have been increasingly captured. To reduce the fishing impacts on these species, exploitation and management must be based on detailed and precise information about their biology. The common mora Mora moro has become the main deep-sea species caught by longliners in the Northeast Atlantic at depths between 600 and 1200 m. In the Azores, landings have more than doubled from the early 2000s to recent years. Despite its growing importance, its life history and population structure are poorly understood, and the current stock status has not been assessed. To better determine its distribution, biology, and long-term changes in abundance and size composition, this study analyzed a fishery-dependent and survey time series from the Azores. M. moro was found on mud and rock bottoms at depths below 300 m. A larger–deeper trend was observed, and females were larger and more abundant than males. The reproductive season took place from August to February. Abundance indices and mean sizes in the catch were marked by changes in fishing fleet operational behavior. M. moro is considered vulnerable to overfishing because it exhibits a long life span, a large size, slow growth, and a low natural mortality.

scholarly journals Long term monitoring of the optical background in the Capo Passero deep-sea site with the NEMO tower prototype

2016 ◽  
Vol 76 (2) ◽  
Author(s):  
S. Adrián-Martínez ◽  
S. Aiello ◽  
F. Ameli ◽  
M. Anghinolfi ◽  
M. Ardid ◽  
...  
Keyword(s):  
Deep Sea ◽  
Optical Background ◽  
Long Term Monitoring ◽  
Term Monitoring

scholarly journals Evidence for benthic-pelagic food web coupling and carbon export from California margin bamboo coral archives

2014 ◽  
Vol 11 (2) ◽  
pp. 2595-2621 ◽  
Author(s):  
T. M. Hill ◽  
C. R. Myrvold ◽  
H. J. Spero ◽  
T. P. Guilderson
Keyword(s):  
Primary Production ◽  
Deep Sea ◽  
Benthic Communities ◽  
California Current ◽  
Strong Relationship ◽  
Nitrogen Isotope ◽  
Carbon Export ◽  
Carbon And Nitrogen ◽  
Pelagic Food Webs

Abstract. Deep-sea bamboo corals (order Gorgonacea, family Isididae) are known to record changes in water mass chemistry over decades to centuries. These corals are composed of a two-part skeleton of calcite internodes segmented by gorgonin organic nodes. We examine the spatial variability of bamboo coral organic node 13C/12C and 15N/14N from thirteen bamboo coral specimens sampled along the California margin (37–32° N; 792 to 2136 m depth). Radiocarbon analyses of the organic nodes show the presence of the anthropogenic bomb spike, indicating the corals utilize a surface-derived food source (pre-bomb D14C values of ∼ −100‰, post-bomb values to 82‰). Carbon and nitrogen isotope data from the organic nodes (13C = −15.9‰ to −19.2‰ 15N = 13.8‰ to 19.4‰) suggest selective feeding on surface-derived organic matter or zooplankton. A strong relationship between coral 15N and habitat depth indicate a potential archive of changing carbon export, with decreased 15N values reflecting reduced microbial degradation (increased carbon flux) at shallower depths. Using four multi-centennial length coral records, we interpret long-term 15N stability in the California Current. Organic node 13C values record differences in carbon isotope fractionation dictated by nearshore vs. offshore primary production. These findings imply strong coupling between primary production, pelagic food webs, and deep-sea benthic communities.

A holistic vision for our future deep ocean

2020 ◽  
pp. 201-206
Author(s):  
Eva Ramirez-Llodra ◽  
Maria Baker ◽  
Paul Tyler
Keyword(s):  
Deep Sea ◽  
Natural Capital ◽  
Synergistic Effects ◽  
Deep Ocean ◽  
Scientific Data ◽  
National Jurisdiction ◽  
Industrial Solutions ◽  
Sound Management ◽  
Holistic Vision

Healthy oceans are essential to maintain a healthy planet, but the ocean is facing many challenges that need urgent attention. Robust scientific data and innovative technological, policy, and industrial solutions are essential to support sound management of the deep-ocean natural capital, both within and beyond national jurisdiction, to ensure future healthy and productive oceans. As with many systems on Earth, there is a delicate ecological balance in the deep ocean that must be maintained. Understanding the interactions of the different components of natural capital in the deep sea is complex, as many of the variables are interlinked and many have cumulative and synergistic effects on the ecosystem. Add to this the global and changing effects of climate change and ocean acidification, and legislators and managers have a tough job ahead to account for all of these issues when designing appropriate conservation measures. It is important that scientists work hand in hand with multiple stakeholders to identify issues and research needs that contribute to enhancing knowledge and the science needed for decision-making to help towards securing a healthy future for our deep-ocean ecosystems and their long-term natural capital.

scholarly journals Quality Control and Pre-Analysis Treatment of the Environmental Datasets Collected by an Internet Operated Deep-Sea Crawler during Its Entire 7-Year Long Deployment (2009–2016)

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2991
Author(s):  
Damianos Chatzievangelou ◽  
Jacopo Aguzzi ◽  
Martin Scherwath ◽  
Laurenz Thomsen
Keyword(s):  
Electrical Conductivity ◽  
Quality Control ◽  
Data Acquisition ◽  
Deep Sea ◽  
Analysis Data ◽  
Environmental Data ◽  
Depth Processing ◽  
Technological Advances ◽  
Scientific Results

Deep-sea environmental datasets are ever-increasing in size and diversity, as technological advances lead monitoring studies towards long-term, high-frequency data acquisition protocols. This study presents examples of pre-analysis data treatment steps applied to the environmental time series collected by the Internet Operated Deep-sea Crawler “Wally” during a 7-year deployment (2009–2016) in the Barkley Canyon methane hydrates site, off Vancouver Island (BC, Canada). Pressure, temperature, electrical conductivity, flow, turbidity, and chlorophyll data were subjected to different standardizing, normalizing, and de-trending methods on a case-by-case basis, depending on the nature of the treated variable and the range and scale of the values provided by each of the different sensors. The final pressure, temperature, and electrical conductivity (transformed to practical salinity) datasets are ready for use. On the other hand, in the cases of flow, turbidity, and chlorophyll, further in-depth processing, in tandem with data describing the movement and position of the crawler, will be needed in order to filter out all possible effects of the latter. Our work evidences challenges and solutions in multiparametric data acquisition and quality control and ensures that a big step is taken so that the available environmental data meet high quality standards and facilitate the production of reliable scientific results.

A Rotary Sonar for Long-Term Acoustic Monitoring of Deep-Sea Gas Emissions

2019 ◽  
Author(s):  
Yann Marcon ◽  
Eberhard Kopiske ◽  
Tom Leymann ◽  
Ulli Spiesecke ◽  
Vincent Vittori ◽  
...  
Keyword(s):  
Deep Sea ◽  
Acoustic Monitoring ◽  
Gas Emissions

A Knowledge Based Approach Towards Design of Mechanical Systems and Components for Deep Sea Mining

2004 ◽  
Author(s):  
Deepak C. Raphael ◽  
Sivasailam Kumaraswamy ◽  
Medisetti M. Rao ◽  
Muthukamatchi Ravindran
Keyword(s):  
Deep Sea ◽  
Engineering System ◽  
Mining Operations ◽  
Near Vision ◽  
Knowledge Based ◽  
Hybrid Products ◽  
Design Support System ◽  
Technological Challenge ◽  
Knowledge Based Design

Development of systems, machinery and components for deep sea mining from 2000–6000 meters depth in the ocean is a major technological challenge. The existing engineering system concepts have been demonstrated for short duration and have to be well evaluated for long term mining operations. The need for conceptualization of new systems has often been emphasized. A Knowledge Based Design Support System has been developed which can be used as a tool to aid a system designer in evaluating existing systems as well as conceive new systems and components. The architecture for evaluating available products and development of evolvable products, hybrid products and genetically modified products are presented. System synthesis using far and near vision fused with conventional methods are described. System variants can be evaluated using a fusion of Analytical Hierarchy Processes (AHP) and Altschullerian approaches.

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