scholarly journals Lessons learned from the monitoring of turbidity currents and guidance for future platform designs

2020 ◽  
Vol 500 (1) ◽  
pp. 605-634 ◽  
Author(s):  
Michael Clare ◽  
D. Gwyn Lintern ◽  
Kurt Rosenberger ◽  
John E. Hughes Clarke ◽  
Charles Paull ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Engineering Design ◽  
Surface Area ◽  
Deep Sea ◽  
Critical Infrastructure ◽  
Lessons Learned ◽  
Turbidity Currents ◽  
Improve Design ◽  
Current Behaviour ◽  
Water Depths

AbstractTurbidity currents transport globally significant volumes of sediment and organic carbon into the deep-sea and pose a hazard to critical infrastructure. Despite advances in technology, their powerful nature often damages expensive instruments placed in their path. These challenges mean that turbidity currents have only been measured in a few locations worldwide, in relatively shallow water depths (<<2 km). Here, we share lessons from recent field deployments about how to design the platforms on which instruments are deployed. First, we show how monitoring platforms have been affected by turbidity currents including instability, displacement, tumbling and damage. Second, we relate these issues to specifics of the platform design, such as exposure of large surface area instruments within a flow and inadequate anchoring or seafloor support. Third, we provide recommended modifications to improve design by simplifying mooring configurations, minimizing surface area and enhancing seafloor stability. Finally, we highlight novel multi-point moorings that avoid interaction between the instruments and the flow, and flow-resilient seafloor platforms with innovative engineering design features, such as feet and ballast that can be ejected. Our experience will provide guidance for future deployments, so that more detailed insights can be provided into turbidity current behaviour, in a wider range of settings.

scholarly journals Challenges for Experience Feedback in Engineering Design

2009 ◽  
Author(s):  
Henrik Nerga˚rd ◽  
Tobias Larsson
Keyword(s):  
Decision Making ◽  
Knowledge Sharing ◽  
Engineering Design ◽  
Empirical Finding ◽  
Qualitative Approach ◽  
Lessons Learned ◽  
Current Feedback ◽  
Active Dissemination ◽  
Different Levels

In this paper empirical finding from a study conducted at an aerospace company is compared to theory regarding Experience Feedback (EF), Lessons Learned (LL) and Decision Making (DM). The purpose with the study was to examine how EF within the organization was conducted and what problems and possibilities that was seen. A qualitative approach was taken and interviews and a workshop was conducted. The empirical findings show that EF exist on different levels within the organization but current feedback processes are currently leaning more towards archiving and storing than knowledge sharing and learning. Also passive dissemination approaches are mostly used whereas active dissemination within the correct context is needed The aim with this paper is to discuss issues and empirical findings that should be considered when creating work methods and systems that support learning by EF and LL dissemination.

A Data-Driven Text Mining and Semantic Network Analysis for Design Information Retrieval

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Feng Shi ◽  
Liuqing Chen ◽  
Ji Han ◽  
Peter Childs
Keyword(s):  
Information Retrieval ◽  
Network Analysis ◽  
Text Mining ◽  
Engineering Design ◽  
Large Scale ◽  
Semantic Network ◽  
Document Retrieval ◽  
Design Information ◽  
Improve Design ◽  
Correlation Degree

With the advent of the big-data era, massive information stored in electronic and digital forms on the internet become valuable resources for knowledge discovery in engineering design. Traditional document retrieval method based on document indexing focuses on retrieving individual documents related to the query, but is incapable of discovering the various associations between individual knowledge concepts. Ontology-based technologies, which can extract the inherent relationships between concepts by using advanced text mining tools, can be applied to improve design information retrieval in the large-scale unstructured textual data environment. However, few of the public available ontology database stands on a design and engineering perspective to establish the relations between knowledge concepts. This paper develops a “WordNet” focusing on design and engineering associations by integrating the text mining approaches to construct an unsupervised learning ontology network. Subsequent probability and velocity network analysis are applied with different statistical behaviors to evaluate the correlation degree between concepts for design information retrieval. The validation results show that the probability and velocity analysis on our constructed ontology network can help recognize the high related complex design and engineering associations between elements. Finally, an engineering design case study demonstrates the use of our constructed semantic network in real-world project for design relations retrieval.

scholarly journals Identification and correlation of distal tephra layers in deep-sea sediment cores, Scotia Sea, Antarctica

1998 ◽  
Vol 27 ◽  
pp. 285-289 ◽  
Author(s):  
S. G. Moreton ◽  
J. L. Smellie
Keyword(s):  
Deep Sea ◽  
Volcanic Ash ◽  
Sediment Cores ◽  
Quaternary Deposits ◽  
Deep Sea Sediment ◽  
Scotia Sea ◽  
Ash Layer ◽  
Tephra Layers ◽  
Major Oxide ◽  
Water Depths

Quaternary deposits in six sediment cores from the Scotia Sea, Antarctica, were examined for the presence of volcanic ash layers. The cores were recovered from water depths of 3369-4025 m. Altogether, 23 ash layers were found, 18 of which have been investigated by electron-probe microanalysis. Deception Island is identified as the source of all the ash layers analyzed. The upper ash layer in each core can be correlated across all six cores, over a distance of -100 km, on the basis of its unusual bimodal composition, major oxide geochemistry and stratigraphie position. Two other ash layers can also be correlated between several of the cores.

scholarly journals The role of clay content and mineral surface area for soil organic carbon storage in an arable toposequence

2021 ◽  
Author(s):  
Steffen A. Schweizer ◽  
Carsten W. Mueller ◽  
Carmen Höschen ◽  
Pavel Ivanov ◽  
Ingrid Kögel-Knabner
Keyword(s):  
Organic Carbon ◽  
Surface Area ◽  
Agricultural Soils ◽  
Mineral Soil ◽  
Clay Content ◽  
Clay Soils ◽  
Mineral Surface ◽  
Mineral Surface Area ◽  
The Impact

AbstractCorrelations between organic carbon (OC) and fine mineral particles corroborate the important role of the abundance of soil minerals with reactive surfaces to bind and increase the persistence of organic matter (OM). The storage of OM broadly consists of particulate and mineral-associated forms. Correlative studies on the impact of fine mineral soil particles on OM storage mostly combined data from differing sites potentially confounded by other environmental factors. Here, we analyzed OM storage in a soil clay content gradient of 5–37% with similar farm management and mineral composition. Throughout the clay gradient, soils contained 14 mg OC g−1 on average in the bulk soil without showing any systematic increase. Density fractionation revealed that a greater proportion of OC was stored as occluded particulate OM in the high clay soils (18–37% clay). In low clay soils (5–18% clay), the fine mineral-associated fractions had up to two times higher OC contents than high clay soils. Specific surface area measurements revealed that more mineral-associated OM was related to higher OC loading. This suggests that there is a potentially thicker accrual of more OM at the same mineral surface area within fine fractions of the low clay soils. With increasing clay content, OM storage forms contained more particulate OC and mineral-associated OC with a lower surface loading. This implies that fine mineral-associated OC storage in the studied agricultural soils was driven by thicker accrual of OM and decoupled from clay content limitations.

scholarly journals Reviews and syntheses: Hidden forests, the role of vegetated coastal habitats in the ocean carbon budget

2017 ◽  
Vol 14 (2) ◽  
pp. 301-310 ◽  
Author(s):  
Carlos M. Duarte
Keyword(s):  
Carbon Sequestration ◽  
Organic Carbon ◽  
Primary Production ◽  
Deep Sea ◽  
Carbon Budget ◽  
Net Primary Production ◽  
Global Ocean ◽  
Coastal Habitats ◽  
Global Carbon Budget ◽  
Global Carbon

Abstract. Vegetated coastal habitats, including seagrass and macroalgal beds, mangrove forests and salt marshes, form highly productive ecosystems, but their contribution to the global carbon budget remains overlooked, and these forests remain hidden in representations of the global carbon budget. Despite being confined to a narrow belt around the shoreline of the world's oceans, where they cover less than 7 million km2, vegetated coastal habitats support about 1 to 10 % of the global marine net primary production and generate a large organic carbon surplus of about 40 % of their net primary production (NPP), which is either buried in sediments within these habitats or exported away. Large, 10-fold uncertainties in the area covered by vegetated coastal habitats, along with variability about carbon flux estimates, result in a 10-fold bracket around the estimates of their contribution to organic carbon sequestration in sediments and the deep sea from 73 to 866 Tg C yr−1, representing between 3 % and 1∕3 of oceanic CO2 uptake. Up to 1∕2 of this carbon sequestration occurs in sink reservoirs (sediments or the deep sea) beyond these habitats. The organic carbon exported that does not reach depositional sites subsidizes the metabolism of heterotrophic organisms. In addition to a significant contribution to organic carbon production and sequestration, vegetated coastal habitats contribute as much to carbonate accumulation as coral reefs do. While globally relevant, the magnitude of global carbon fluxes supported by salt-marsh, mangrove, seagrass and macroalgal habitats is declining due to rapid habitat loss, contributing to loss of CO2 sequestration, storage capacity and carbon subsidies. Incorporating the carbon fluxes' vegetated coastal habitats' support into depictions of the carbon budget of the global ocean and its perturbations will improve current representations of the carbon budget of the global ocean.

Organic- or Inorganic-based Nanomaterials: Opportunities and Challenges in the Selection for Biomedicine

2021 ◽  
Vol 27 ◽  
Author(s):  
Ranjith Kankala
Keyword(s):  
Chemical Composition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Therapeutic Strategies ◽  
Lessons Learned ◽  
Clinical Translation ◽  
Significant Progress ◽  
Morphological Attributes ◽  
The Past ◽  
Selection For

: Since the inception of nanotechnology, several efforts have been dedicated to fabricating diverse nanodevices with exceptional performance. These innovative constructs have been applied in medicine due to their tailorable physicochemical properties (chemical composition, optical activity, spectra, and charge) and morphological attributes (size, shape, and surface area). Moreover, these versatile nanomedicines could promisingly offer better performance over the conventional therapeutic strategies. Broadly speaking, in terms of chemical composition, nanobiomaterials are classified into two predominant categories of organic and inorganic-based components. Despite their success and enormous versatile advancements in the past two decades, the significant progress towards clinical translation has been hampered by their corresponding intrinsic limitations. In this perspective, we give a brief overview of these organic- and inorganic-based materials, highlighting opportunities and challenges towards their utilization in medicine. Finally, we provide an interesting outlook in lessons learned and looking forward to developing these materials, emphasizing their scope towards clinical translation.

Substantial accumulation of mercury in the deepest parts of the ocean and implications for the environmental mercury cycle

2021 ◽  
Vol 118 (51) ◽  
pp. e2102629118
Author(s):  
Maodian Liu ◽  
Wenjie Xiao ◽  
Qianru Zhang ◽  
Shengliu Yuan ◽  
Peter A. Raymond ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Food Webs ◽  
Deep Sea ◽  
Anthropogenic Activities ◽  
Sediment Cores ◽  
Anthropogenic Sources ◽  
Biogeochemical Cycle ◽  
Vertical Profiles ◽  
Surface Ocean ◽  
Increasing Trends

Anthropogenic activities have led to widespread contamination with mercury (Hg), a potent neurotoxin that bioaccumulates through food webs. Recent models estimated that, presently, 200 to 600 t of Hg is sequestered annually in deep-sea sediments, approximately doubling since industrialization. However, most studies did not extend to the hadal zone (6,000- to 11,000-m depth), the deepest ocean realm. Here, we report on measurements of Hg and related parameters in sediment cores from four trench regions (1,560 to 10,840 m), showing that the world’s deepest ocean realm is accumulating Hg at remarkably high rates (depth-integrated minimum–maximum: 24 to 220 μg ⋅ m−2 ⋅ y−1) greater than the global deep-sea average by a factor of up to 400, with most Hg in these trenches being derived from the surface ocean. Furthermore, vertical profiles of Hg concentrations in trench cores show notable increasing trends from pre-1900 [average 51 ± 14 (1σ) ng ⋅ g−1] to post-1950 (81 ± 32 ng ⋅ g−1). This increase cannot be explained by changes in the delivery rate of organic carbon alone but also need increasing Hg delivery from anthropogenic sources. This evidence, along with recent findings on the high abundance of methylmercury in hadal biota [R. Sun et al., Nat. Commun. 11, 3389 (2020); J. D. Blum et al., Proc. Natl. Acad. Sci. U. S. A. 117, 29292–29298 (2020)], leads us to propose that hadal trenches are a large marine sink for Hg and may play an important role in the regulation of the global biogeochemical cycle of Hg.

New subgenus and new species of marine benthic ostracods of genus Doloria (Ostracoda; Myodocopina) from the Southern Ocean

Zootaxa ◽  
2012 ◽  
Vol 3356 (1) ◽  
pp. 1 ◽  
Author(s):  
VLADIMIR G. CHAVTUR ◽  
SIMONE N. BRANDÃO ◽  
ALEXANDER G. BASHMANOV
Keyword(s):  
New Species ◽  
Southern Ocean ◽  
Deep Sea ◽  
Novel Species ◽  
The Other ◽  
The Novel ◽  
Atlantic Sector ◽  
New Subgenus ◽  
Fifth Limb ◽  
Water Depths

The project ANDEEP was designed to fill gaps in the knowledge of the biodiversity of the Southern Ocean deep sea. Threeoceanographic cruises (ANDEEP I, II and III) were undertaken in 2002 and 2005 in the Atlantic Sector of the SouthernOcean. Hundreds of samples were collected from 40 stations with water depths ranging from 748 to 6,348 m. Investiga-tions were carried out on a broad range of taxa, including bacteria, meio-, macroand megafauna. Approximately 5000ostracods were collected, which included 29 specimens of Doloria (Dolorietta) subgen. nov.The subdivision of the genus Doloria Skogsberg, 1920 into two subgenera, Doloria (Doloria) and the novel subgenusDoloria (Dolorietta), is based on differences in the structures of the fifth limb, the armature of the sensory bristle on the5th segment of the antennula, and the number of bristles on the 4th endite of the sixth limb. Four new species in the newsubgenus were identified from the ANDEEP samples. The new subgenus and the four novel species are described andillustrated. Two of these new species are named Doloria (Dolorietta) antarctica sp. nov. and Doloria (Dolorietta) sextafiliformis sp. nov., but the other two species are left in open nomenclature (i.e. Doloria (Dolorietta) sp. nov. 1 and Doloria(Dolorietta) sp. nov. 2) because only juveniles were found in our material. Keys to the subgenera and species of Doloria are provided.

scholarly journals UK deep‐sea conservation: Progress, lessons learned, and actions for the future

2019 ◽  
Vol 30 (2) ◽  
pp. 375-393
Author(s):  
Peter D. Chaniotis ◽  
Laura M. Robson ◽  
Anaëlle J. Lemasson ◽  
Alice L. Cornthwaite ◽  
Kerry L. Howell
Keyword(s):  
Deep Sea ◽  
Lessons Learned ◽  
The Future
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