Search

The ECOREST_AUV campaign will focus on monitoring restored populations in closed areas and adjacent fishing grounds to assess the evolution of restored populations and monitor the evolution of ecosystem services provided, as well as the provision of habitat, breeding areas or a possible spillover effect of closed areas in adjacent areas

The ocean currently accumulates 93% of the excess heat and 31% of the excess CO2 generated by human activity. The AMOC influences the European climate in a very relevant way in that of the Iberian Peninsula and amplifies the capture of anthropogenic CO2 with an average rate that exceeds 50% of the average ocean value. Besides, in the subpolar gyre of the NA, ocean acidification reaches abyssal depths, endangering the future of ecosystems supported by cold water coral structures. The recent weakening of the AMOC has been noted and is expected to become more pronounced in the coming decades. The IPCC highlights the lack of observations to quantify the magnitude of this reduction. Therefore, observational monitoring (present and past) of ocean circulation and acidification in the NA is essential to advance the accurate detection of anthropogenic impact and improves the projections of the coupled climate models that support the IPCC reports for the subpolar gyre of NA. The paleoceanographic information from this area allows us to give context and establish the nature of previous changes to the instrumental records in different climatic contexts. BOCATS2 has as its main observational contribution the continuation of the biennial programme of oceanographic cruises in section A25-Ovide within the framework of the international GO-SHIP programme. Also, the new challenge of assessing the variability of the deep circulation of the NA will be faced, improving the spatiotemporal resolution of current currents by deploying the deep-ARGO array and at a submillenary scale using paleoceanographic data obtained in sedimentary records from key sites such as the Bight and Charlie-Gibbs fracture zones. The high-quality observations foreseen in the SPNA will contribute to the early detection of the alteration of the carbon cycle and will allow the precise estimation of the storage rates of heat, CO2 and N2O, connecting these changes to the variability of the AMOC at different time scale

BOCATS2, a continuation of the previous BOCATS project (2014-2017), will be a main contribution to the observation of the NA subpolar gyre by continuing the occupation of the biennial section A25-Ovide (2021 and 2023) within the framework of the international GO-SHIP programme. A particular focus will be given to the new challenge of assessing the variability of the deep circulation in the NA, improving the spatial-temporal resolution of deep currents and water mass characteristics by deploying a regional deep-ARGO array and, at a submilenary scale, using paleoceanographic data obtained in sedimentary records from key sites, such as the Bight and Charlie-Gibbs fracture zones. The high-quality observations foreseen in the SPNA will contribute to the early detection of the alteration of the carbon cycle allowing the precise estimation of the heat, CO2 and N2O storage rates and, ultimately, to find the connection between these changes and the variability of the AMOC at different time scales. The natural and anthropogenic fluxes of heat, CO2 and N2O will be evaluated, as well as the present and submillenary scale transport of sediments and biogenic elements, and the impact of acidification on these timescales by means of the analysis of CaCO3 and organic carbon fluxes to the sediment. Besides, the current ocean acidification rates will also be quantified by evaluating the present situation and establishing future projections. These new observation-based estimates will be a valuable result that will be used to validate the predictions from the models (GCMs and ESMs from CMIP5-6) for the 2°C warming scenario. Finally, special attention will be paid to the rates of elevation of aragonite saturation horizons in deep layers, where the impact on the ecosystems sustained by calcareous organisms is potentially imminent

The STREGTH cruise aims at providing information about the recent (Quaternary) activity of the active faults in the Moroccan and Spanish margins and about their tectonic structure, with special emphasis on the faults location, geometry and seismotectonic significance. The cruise is planned to acquire high-resolution bathymetry, image and seismic data from 15 March to 21 April 2023. The main goal of STRENGTH is collecting high-resolution bathymetry, image and seismic data with the Spanish R/V Sarmiento de Gamboa. For this we will use an autonomous underwater vehicle (AUV), a remote operated vehicle (ROV), a side-scan sonar (DT-1), sparker seismic system and a streamer with hydrophones, and deploy Ocean Bottom Seismometers (OBS) on the sea floor and we will use a group of air guns for the acoustic source

In the FAR-DWO DS1 oceanographic cruise we analyze the hydrographic and sedimentological variability of the Denmark Strait Overflow using water column and seafloor observation and sampling techniques. We also deploy multi-instrumented mooring lines at depths between 1000 m and 2000 m to record information of the dense current during a whole year. The FAR-DWO DS1 cruise will last from July 19th to August 12th 2023 onboard the oceanographic vessel Sarmiento de Gamboa (CSIC). We are a team of around thirty experts from the Universitat de Barcelona (UB), Universidad de Las Palmas de Gran Canaria (ULPGC), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), University of Iceland (UI), and the company specialized in satellite technology Lobelia Earth, and we count on the technical support of Unidad de Tecnología Marina (UTM-CSIC)

The general objective of DESAFIO is to study the flow of particulate and active carbon (the one carried out by the migrating organisms of the zooplankton and micronekton), as well as the selection of meso- and bathypelagic migrants in the area detected between the upwelling of the African coast, the oligotrophic waters of the subtropical gyre, and the Azores current, ending in the productive waters north of the Azores. The campaign design, divided in two parts, will allow studying an important variety of productive scenarios in the ocean in two seasons of the annual cycle characterized by the highest productivity in winter and oligotrophy in autumn

SAGA: The South Atlantic GAteway in the global conveyor belt. The general objective of the main SAGA project is to quantify and monitor the returning limb of the Atlantic Mmain meridional Overturning Circulation (AMOC) in the South Atlantic Ocean, with special attention to the interior-ocean zonal flows linking the eastern and western South Atlantic basins. To complete tasks of the main project, in 2021 were deployed a series of devices to measure different oceanographic variables at a depth between 2 and 4 kilometres deep in 7 seabed locations along the 10ºW meridian and between 34ºS and 19ºS. The main objective of the present SAGA REC cruise consists in the recovery of three previosly imstalled mooring with corresponded equipment and, in case of favourable meteorological conditions, to perform the CTD casts untill the bottom in the places where the mooring were installed and where the PIESs (Pressure Inverted Echo Sounder) are still remain to measure. Additionally is planned to performe the vertical hydrographyc transection in the shelf area of Uruguay

Logistic operations

The DOGMA cruise is a single day campaign to collect water and particles for subsequent organic matter degradation experiments

Training of students of the master of "Oceanography and managment of the marine environment" from Barcelona University in the acquisition of oceanographic data

A joint effort between BIology and TEchnology to monitor and recover fishery-impacted species and ecosystems by implementing a network of marine Reserves (BITER).The objective of the campaign is to know the spatial distribution of the larval stages of the Norway lobster Nephrops norvegicus, the target species of the project, and it is also intended to characterize the water masses associated with the distribution of the Norway lobster, oceanographic data that will be used to the validation of the bio-hydrodynamic model of the study area and for the elaboration (and validation) of a model of distribution, abundance and population connectivity of N. norvegicus

The FAR-DWO project aims to investigate the physical processes involved in the spread of dense water cascades, quantify their erosion capacity, transport and deposit sediment and analyze its conservation in the past climate. The objective of the CCC2-4 campaigns is to carry out a CTD and ADCP mesh for the Characterization of hydrological conditions during submarine waterfall events. In addition, if oceanographic conditions allow it, it is planned to carry out a mapping bathymetry and characterization of the seabed in great detail of a specific sector of the head (less than 500 m deep) of the Cap de Creus canyon by using of the AUV Girona 500

The main objective of the POLAR CHANGE Antarctic expedition is to investigate the ocean-atmosphere interface and the cloud condensation nuclei generation under different scenarios. We investigate the role that marine microorganisms and sea-ice melting have in the primary and secondary marine aerosol generation. Online atmospheric measurements and in-situ lab experiments reproducing the ocean-atmosphere interface will provide data to understand nucleation events and the generation of clouds precursors

MARine Biodiversity and Ecosystem Functioning leading to Ecosystem Services. The project aims to evaluate and characterise the links between marine biodiversity, ecosystem functioning, ecosystem services and the resulting societal goods and benefits in coastal communities. The results will be captured in easy-to-use tools to help practitioners and policy to maximise the ecological value and optimise a sustainable socio-economic use of the marine system for current and future generations

The MICOLOR-1 campaign has been designed to capture the maximum diversity of stations based on their productivity. It is about measuring sedimentation flows to the bottom of the ocean and at the same time measuring the structure of the communities of microorganisms in the particles on the surface, in the deep maximum of chlorophyll, at approx. 200 m and in the mesopelagic. The surface and those depths will be characterized by measuring nutrients, chlorophyll, flow cytometry, and the activity of algae and bacteria. The community will be studied by DNA sequencing on the particles

Connectivity of particle-attached prokaryotes across continental margins and their potential use as particle source and organic carbon degradation proxies (CONPART).This campaign is part of the study of the connectivity of microbial communities associated with suspended particles on continental margins along a vertical gradient in the water column and horizontally along a submarine canyon to evaluate their potential use. as tracers of the origin and level of degradation of organic particles. The objective of the CONPART project is to improve our understanding of the interactions between the dynamics of particles and the microbial diversity associated with them and also to know their functionality to see if they are functionally diverse, and can adapt to the environmental changes that occur during the particulate matter transport

Assessment of fishing grounds Restoration after a Change of bottom trawling Otter boards (ARCO). The main objective of the ARCO project is to study the current sedimentary processes related with trawling activity in the Palamós submarine canyon after the change of trawl doors by the Palamós harbor fleet. The impacts of this type of fishing in deep-sea environments are considered very high due to their intensity and recurrence, and to the fact that sediment dynamics are less energetic and the benthonic ecosystems are more vulnerable and have less resilience than in neritic or shelf environments

CHALLENGE-2 is the second and last campaign of the CHALLENGE project (Human pressures and natural hazards: challenges for the Antarctic marine benthos) which aims to experimentally analyze and describe the human pressures and natural hazards that challenge the Antarctic marine benthos, based on the background of the team's previous projects in this region. Changes in biodiversity will be assessed using different methodologies, with special emphasis on those poor-known habitats, across a latitudinal gradient from Rothera Island to South Orkney Islands, sampling in both in pristine and more polluted areas (tourist areas, with the presence of stations, etc.)

Assessment of Bottom‐trawling Resuspension Impacts in deep benthic Communities (ABRIC)

Transit voyage without any scientific work.

Study of the Spanish Economic Zone in the Balearic sea

The cruise is designed to analyse the direct environmental effects on the seabed and the water column arising from the deployment and operation of a prototype polymetallic nodule collector. The state of the seabed before and after the passage of the nodule collector vehicle is investigated by recording a high-definition video installed on a remotely operated vehicle (ROV). The dispersion of the resuspended material plume by the nodule collector is monitored by a set of moorings deployed around the circulation zone of the nodule collector. Anchors include turbidimeters, current meters, a particle camera and a grain size analyser. Likewise, a transect of CTDs is repeated several times and a follow-up of the plume with the CTD behind the collector. The underwater sound impact produced by the nodule collector is recorded with a deep-sea hydrophone located at one of the anchors

The general objective of e-IMPACT is to study the linkage between the dynamics of mesoscale and sub-mesoscale processes occurring along the life history of cyclonic and anticyclonic eddies in the Canary Eddy Corridor (CEC), and their effects on the structure and metabolism of the planktonic community, as well as in their role in the vertical carbon flux to the deep ocean. e-IMPACT will address the coupled dynamics between food-web diversity and function, in relation to the physical and chemical conditions, the origin and composition of DOC and POC and their contribution to remineralization rates in the twilight zone of the ocean

The main objective is to provide second year students with a campaign experience as similar as possible to oceanographic campaigns conducted by marine science researchers. With this objective, the aim is to expose students to different sampling techniques in chemical oceanography and marine geology

The overall objective of this study is to identify the changes and risks for marine ecosystem functioning and its biodiversity deriving from the potential impact of climate change on Iberian Upwelling fronts

The BITER-1 oceanographic campaign is part of the multidisciplinary project "Joint effort between BIology and TEchnology to monitor and recover species and ecosystems impacted by fishing through a network of marine Reserves (BITER)". The main objectives of the BITER-1 campaign are: 1) to obtain images with the ROV Liropus 2000 and with the AUV Girona 500 of the initial state of the 4 Reserves of Fishing Interest and their Control Areas at the time of the closure of the fishing activity; 2) to carry out the first tests of the use of new technology for the evaluation of the state of the ecosystem, as well as tests of the active monitoring of Nephrops norvegicus lobster individuals previously marked with experimental acoustic sensors. Individuals of the 3 main species of this habitat (an octopus, a fish and a shark) will also be equipped with sensors

The MARIBNO project is located in the NW zone of Iberia, which constitutes an ideal environment to raise the following main objectives: 1. Study of the cortical structure at the western end of the Cantabrian Mountains and the transition zone between the western and northern margins of Iberia. 2. Study of the tectonic control exerted by the previous structures during the two main alpine stages. 3. Mapping and characterization of cortical domains using a multidisciplinary approach. Definition and application of geophysical and geological criteria applicable to the zonation of cortical domains in other parts of the world with similar contexts

EXport Processes in the Ocean from Remote Sensing (EXPORTS) is a large-scale NASA-led field campaign that will provide critical information for quantifying the export and fate of upper ocean net primary production (NPP) using satellite observations and state of the art ocean technologies. The goal of EXPORTS is to understand how the organic carbon makes it to the twilight zone and deep ocean interior, and how lon it stays there, which is vital to understanding present and future ocean ecosystems and global climate

The MIAU-DCM campaign will study the biological characteristics of the deep chlorophyll maximum in the Northwest Mediterranean. To do this, the first 150-200 meters of the water column will be sampled with CTD along a transect between the towns of Blanes and a point near Cape Formentor, and from the continental shelf (depth 40-50 meters). Once the depth of the DCM has been defined, and its variability along the transect, the stations in which biological sampling will be carried out will be defined, which will consist of taking samples from approximately 100 m and the surface. In addition, station D (in the middle of the basin) will be characterized up to 2500 meters

The BIOMAP (Bio-Optical mapping of Marine Properties) campaign consists of sampling activities of optical properties of the surface layer in an area off the Ebro Delta and close to the Casablanca crude oil extraction platform. The objective is to collect accurate data for characterization and validation of the AERONET-OC measurement node installed on the platform. AERONET-OC is the main automatic network of optical radiometers for satellite radiometer validation activities

The general objective of the RADMED-ESMARES project is the multidisciplinary monitoring of the shelf and continental slope waters of the Spanish Mediterranean, including both the peninsular coast and the Balearic Islands. The area to be covered is very wide, so in order to optimize the available means, 17 sections are carried out covering the shelf and slope at strategic points of the coast, as well as others in the area of the channels of the Balearic Islands and the Gulf of Valencia where the transports through these determine to a great extent the regional hydrodynamics and affect the general circulation of the MEDOC. The variables to be monitored are physical, chemical and biological variables, aiming to study the hydrographic conditions, planktonic communities, seasonal cycles of these variables and their interannual variability. This monitoring allows us to implement our data banks, generate time series, establish ocean climatologies, study oscillations, trends, anomalies and their relationship with global warming and climate change

The aim of the ECOSUMA project is to study one the main bottlenecks that prevent the integral culture of the common octopus Octopus vulgaris. For that purpose we undertake a multidisciplinary survey that will relate chemical and physical parameters with the abundance of paralarvae in different strata of the water column. We use a multinet gear and deploy rosettes and CTD along eight transects in the proximity of Spanish and norther Portuguese waters. We also measure turbidity in most tows undertaken

ZEE-2021: Study of the Spanish Economic Zone in the Canary Islands

SAGA: The South Atlantic GAteway in the global conveyor belt. The general objective of the SAGA project is to quantify and monitor the returning limb of the Atlantic Meridional Overturning Circulation (AMOC) in the South Atlantic Ocean , with special attention to the interior-ocean zonal flows linking the eastern and western South Atlantic basins. During the SAGA10W cruise, the installation of different equipment on the seabed is planned, that will make it possible to find out how the currents of the South Atlantic behave and how they are connected with the Southern Ocean. During the cruise it is planned to deploy a series of devices to measure different oceanographic variables at a depth between 2 and 4 kilometres deep in 7 locations located between 34ºS and 19ºS along the 10ºW meridian: 4 PIES (Pressure Inverted Echo Sounder) —which allow the reconstruction of the thermohaline structure of the water column— and 3 anchors that incorporate current meters —the currents— and CTDs —the temperature, salinity and conductivity of the water. The anchors will be in the water for two years, after which the data will be collected and analysed. The PIES, on the other hand, will remain on the seabed for four years, although at 16 and 32 months some units will be released and will be raised to the sea surface to transmit the collected data

BACT&PLAST-1 campaign will take place in the area is in front of the rivers mouths Llobregat and Besos. The tasks to be carried out consist of carrying out CTD transects and water sampling, obtaining sediment cores by multicorer, and trawling the manta trawl for microplastic fishing

The BOCATS-2_LEG2 cruise is a part of the BOCATS project. During this cruise will be obtained a detailed mapping of the Bight fractures (Bight Fracture Zone - BFZ), the internal structure of the first meters of sedimentary fill and the most appropriate choice of sampling points. Also, another part will consist of obtaining samples of the surface sediments. Both operations will be performed at four different points along the fracture area. The fracture has a special relevance since it represents an important part of the transport of the Iceland-Scotland Overflow Water (ISOW) through the ridge

Leg 0 of cruise iMIRABILIS-2 will focus on the collection of multibeam bathymetry and geological and biological data on the north part of the Azores-Biscaya Rise (ABR). This area is part of a roughly linear north-east-south-west trending feature, with approximately 700 km long, rising up to 3,000 m above the surrounding seafloor (e.g. Whitmarsh et al., 1982). Very few studies have focused on the ABR and data on this geomorphological feature is still scarce notwithstanding its importance during the opening and evolution of the North Atlantic basin during the last 75 Myr, which was also influenced by the Azores hotspot. During the ROV dives it is expected to observe and collect submarine volcanic rocks in order to characterize the geological environment at this location and to study the mantle components along with the magmatic processes that sourced the volcanism and created this major geological structure. The bathymetric highs and seamounts occurring in the North Atlantic also constitute hotspots of biodiversity, hostingdeep water coral reefs and deep sea sponges forming complex habitats that are also considered to be vulnerable marine ecosystems (VMEs). The collection of environmental baseline data on these areas is paramount not only to explore remote areas with scarce data but also for the development of a coherent multidisciplinary approach focused on the adoption of effective measures for protection and conservation of the marine environment

The SUMMIT campaign consists of comparing three stations in the Catalan-Balearic Sea: station D in deep waters in the middle of the basin, on the way to the Menorca Canal, where shallow CTD sets will be made (200 m); station E in deep waters but somewhat more productive to the NE, where the same CTD sets will be made; and station S in platform waters near Blanes, with similar routines. Most of the tasks will consist of experiments on deck, especially in incubation tanks bathed with surface water

Polycrystalline body-centred cubic (BCC) steel is the most commonly used structural material in the transportation industry. In order to optimize sustainable use of steel materials in welded structures such as ships, better fundamental understanding of the factors affecting material behaviour is required in different length scales. This thesis studies the length scale interface between microstructural features and continuum scale deformation in BCC steel materials. Special attention is paid on characterization of microstructure and local plastic deformation in heterogeneous steel weld metals. In this work, microstructural characteristics are correlated with plastic deformation response, and the fundamental deformation mechanisms are resolved using electron backscatter diffraction. The local deformation process is characterized for welded steel using instrumented indentation testing in different length scales, ranging from a fraction of one grain to tens of grains. A serial sectioning procedure is developed in order to consider the stochastics of the plastic deformation process in heterogeneous microstructures. Furthermore, advanced orientation data post-processing and misorientation analysis are utilized to identify the plastic deformation zone and formation of dislocation cells beneath hardness indentations. The results of the thesis reveal the importance of grain size dispersion to mechanical properties, and the significance of grain interactions for the plastic deformation process in polycrystalline BCC steel. Comparison between base and weld metal revealed that the size of the plastic deformation zone is proportional to the average grain size. A transition region was defined between continuum and single crystal material behaviour, where the interaction of grains of different size controls the local plastic deformation of polycrystalline steel. The strongest influence grain interaction on hardness variation was found to take place at indentation diagonal length, Rakenneteräkset ovat yleisimmin käytetty materiaali kuljetusvälineteollisuudessa. Jotta perusmateriaalin ominaisuuksia voidaan hyödyntää parhaalla mahdollisella tavalla hitsatuissa rakenteissa kuten laivoissa, tarvitaan syvällistä tietoa materiaalin käyttäytymisestä. Tämä väitöskirja tutkii monikiteisiä teräksiä, joissa on tilakeskeinen kuutiollinen kiderakenne. Olennaista teräksen tehokkaassa hyödyntämisessä on mikrorakenteen ja lujuuden välisten tekijöiden määrittäminen. Tässä työssä keskitytään hitsatun rakenneteräksen mikrorakenteen ja plastisen deformaation karakterisointiin. Mikrorakenne ja plastinen deformaatio mitataan elektronisuihkumikroskopian (SEM) avulla, sekä mikrorakenteen geometrisia mittoja verrataan paikallisiin materiaalin lujuusarvoihin. Lujuutta mitataan instrumentoidulla kovuuskokeella eri mittakaavoissa, kattaen deformaatioalueen koon yksittäisen kiteen murto-osasta kymmeniin kiteisiin. Kovuusmittauksista tehdään mikrorakenneanalyysiin soveltuvat poikkileikkaukset, jotta deformaatioprosessin tilastollinen vaihtelu pystytään määrittämään. Kideorientaatioanalyysiä varten kehitetään jälkikäsittely- ja analysointimenetelmät, joilla paikalliset deformaatioalueet voidaan määrittää kiteeseen muodostuvien alirakenteiden perusteella. Työn tulokset osoittavat, että kidekokojakauma vaikuttaa huomattavasti hitsatun teräksen lujuuteen ja plastisen deformaatioalueen laajuus osoitetaan riippuvaiseksi teräksen keskimääräisestä kidekoosta. Lisäksi eri kokoisten kiteiden vuorovaikutus vaikuttaa oleellisesti deformaatioprosessiin. Kovuusmittausarvojen hajonta on suurinta kidevuorovaikutuksen takia, kun kovuusmittausjäljen diagonaalimitta on 0.1 – 2 kertaa keskimääräinen kidekoko (dv). Tämä mittakaava sijaitsee yksittäiskiteen deformaation ja kontinuumimekaniikan rajapinnassa. Mitattu kovuuden hajonta pienenee huomattavasti, kun kovuusmittausjäljen koko on moninkertainen keskimääräiseen kidekokoon nähden. Tässä mittakaavassa lujuuteen vaikuttaa eniten keskimää

The purpose of this paper is to present a concept of so called intelligent consultant' - that is a tool that provides C&C system operator a support in case the gathered information (acquired from observation means) is incomplete, imprecise or even conflicted. It is the intention of the authors to focus on the methodological aspect of the problem which may be formed as: Does Dezert-Smarandache Theory (DSmT) of plausible and paradoxical reasoning enable to deal with difficult target classification which normally happens in maritime C&C systems. For this reason a comparison of hard-decision fusion, DSmT fusion and a combination of DSmT and ontology fusion algorithms has been established. Some numerical experiments have been made and their results have been delivered in this paper., See also ADB381582. RTO-MP-IST-087 Information Management - Exploitation (Gestion et exploitation des informations). Proceedings of RTO Information Systems Technology Panel (IST) Symposium held in Stockholm, Sweden on 19-20 October 2009., The original document contains color images.

Stealth is an important factor in littoral operations. Stealthy power sources for underwater vehicles include air-independent propulsion technologies, such as fuel cells, perhaps hybridized with an energy store such as an advanced battery. The hybrid combination provides the most covert solution, with good underwater endurance. Of the fuel cell technologies examined, the proton exchange membrane fuel cell (PEMFC) currently offers the best performance. For the very long transit patrols of large submarines, nuclear power must be a component of the solution, but perhaps as part of an integrated hybrid power source system rather than as the sole main power source. (5 tables, 10 figures, 6 refs.), See also ADM201697. Published in RTO-MP-104. Presented at the RTO Applied Vehicle Technology (AVT) symposium on "Novel Vehicle Concepts and Emerging Vehicle Technologies (Nouveaux concepts et technologies emergentes pour plates-formes)" held in Brussels, Belgium, on 7-10 Apr 2003. The original document contains color images.

The research described in this report represents an important step forward in the development of seabed classification technology. First, it represents the application of the QTC VIEW technology to a new seabed environment. The data sets analyzed here involve reef seabeds which have not previously been studied. Second, they represent a consistent effort to compare the results obtained by using two different frequencies of sounder over the same seabed type. The results suggest that both 200 kHz and 24 kHz sounders can be used to classify the four bottom types involved in the study. However, it is clear that multispectral seabed classification holds significant potential in situations where, for example, a gravel bedform is overlain by a thin veneer of mud., Text in English. Abstract in French and English. Original contains color plates: All DTIC reproductions will be in black and white.

The conversion of an experimental tank at Glen Fruin into one of the world's largest stratified test facilities is described. The stages of development and the commissioning tests are reported. The tank is shown to offer a stable environment for research on buoyancy influenced flows with relatively weak density gradients and a relatively large cross section. (Author)

An axisymmetric boundary-layer prediction method has been modified to include an approximate representation of a lightly-loaded propulsor. It is shown that, given, the average increase in velocity at the propulsor position, the method is capable of predicting the effect of single and contra-rotating propellers on the boundary-layer flow in the vicinity of the propulsor. The propulsor effect is shown to be insignificant more than one propulsor diameter upstream.

The Green's functions in the region between planes on which either Neumann or Dirichlet boundary conditions apply are obtained in the form of double Fourier series expansions. A closed form expression for the sound field in an axisymmetric water filled channel is obtained in order to illustrate the usefulness of the expansions. Problems associated with numerical evaluation are discussed and some numerical examples are given. Keywords: Great Britain; boundary values problems; fluid-structure interactions. (Author)

Compression tests on five stiffened N8 aluminium alloy plates covering typical full scale warship scantlings are described. The panels were manufactured using normal shipyard production methods to ensure typical initial distortion and residual stresses. Maximum loads and post-buckling load/deflection results are compared with theoretical predictions using the ARE computer program N106C. Keywords: Buckling, Strength, Test, Compression, Stiffened plate, Interframe, Yield.

This report shows comparisons of velocity profiles measured at the tail end of two axisymmetric bodies with velocity profiles produced by a potential flow and first order boundary layer computer model. The computer program can produce excellent agreement with measured data if the boundary layer transition position can be optimized in the computation. This program will be a valuable aid to determining the model and duct configuration although some preliminary testing of models may be necessary to establish the actual boundary layer transition position and to change it using a boundary layer trip device or to optimise the position selected for the computation. (Great Britain)