Protective effect of ultrathin alumina film against diffusion of iron into carbon fiber during growth of carbon nanotubes for hierarchical composites investigated by ptychographic X-ray computed tomography

Composite materials based on carbon fiber (CF) are prone to failure at the fiber-matrix interface upon compression or stress transverse to the fiber axis. The direct growth of carbon nanotubes on CF constitutes a novel approach to enhance the mechanical properties of the interface. However, the challenge is that, during the growth, tensile properties of the fiber are altered due to the diffusion effect of iron nanoparticles used in the process, leading to CF surface defect formation. In this work, we deliver and discuss an analysis methodology on ptychographic X-ray computed tomography (PXCT) images in order to assess the iron nanoparticle abundance within CFs. PXCT provides 50 nm - resolved 3D electron density maps of the CFs. We evidence the protective effect of an ultrathin alumina film against iron infiltration into CF during the CNT growth. This method potentially allows to evaluate the efficiency of other diffusion-minimizing approaches. The conclusions of the PXCT examination are validated by energy-dispersive X-ray spectroscopy and scanning transmission electron microscopy carried out on thin sample slices cut with a focused ion beam. The results provide a new insight into the mechanical performance of CFs and therefore constitute valuable knowledge for the development of hierarchical composites

Effects of spatial dispersion in near-field radiative heat transfer between two parallel metallic surfaces

We study the heat transfer between two parallel metallic semi-infinite media with a gap in the nanometer-scale range. We show that the near-field radiative heat flux saturates at distances smaller than the metal skin depth when using a local dielectric constant and investigate the origin of this effect. The effect of non-local corrections is analysed using the Lindhard-Mermin and Boltzmann-Mermin models. We find that local and non-local models yield the same heat fluxes for gaps larger than 2 nm. Finally, we explain the saturation observed in a recent experiment as a manifestation of the skin depth and show that heat is mainly dissipated by eddy currents in metallic bodies.Comment: Version without figures (8 figures in the complete version

Larval distribution of commercial fish species in waters around Ireland

In April 2000 a base line survey was conducted on the larval distribution of commercial fish species off the west, north and south coasts of Ireland. Ichthyoplankton samples and in situ CTD data were collected, whilst simultaneously capturing remote sensing images of chlorophyll and sea surface temperatures. The survey sampling area covered the Celtic Sea from the Irish south coast to 49 degree N, the western shelf including the Porcupine Bank and the northern shelf up to the Stanton Bank. The sample grid design was based on the international mackerel & horse mackerel egg survey with station spacings of 0.5 degree latitude and 0.5 degree longitude. Ichthyoplankton samples were collected with a Gulf III plankton sampler, which was deployed on oblique tows from the surface to within 5 metres of the bottom (200m max). A self-logging CTD sensor (Promonitor) was attached to the Gulf and recorded depth, temperature and salinity profiles for each deployment. Results from the Promonitor CTD showed that strong temperature and salinity gradients were encountered during the survey. Lowest temperatures coincided with lowest salinity in the North Channel of the Irish Sea while highest salinities and temperatures were found to the south west of Ireland.Thermal fronts were found in the eastern Celtic Sea and on the north west coast of Ireland.The AVHRR images showed a progressive increase in surface temperatures in the Celtic Sea and west of Ireland. Highest surface chlorophyll concentrations were associated with cooler less saline water in the Irish Sea and the coastal areas around Ireland. In the western Celtic Sea surface chlorophyll concentrations increased as the survey progressed to form a phytoplankton bloom towards the end of the survey. Larvae of interest showed distinct distribution patterns, with some species being confined to particular areas or spawning grounds while others were spread over the whole survey area. The survey identified two important larval hotspots: Cod larvae were concentrated in the eastern Celtic Sea, where other gadoid species such as haddock, whiting, pollack and saithe were also found in high numbers.This area is associated with the Celtic Sea front and shows increased primary productivity, which could present a favourable environment for successful larval survival. Stations in the southwest of Ireland sustained high concentrations of hake, megrim and mackerel larvae. The waters with high numbers of these three species stretched from shallow inshore stations to deeper ones along the continental shelf and were characterised by high temperatures and salinities. SeaWIFS satellite images suggest the formation of a phytoplankton bloom within this larval hotspot, which would provide the necessary resources for successful larval growth.Funder: Marine Institut

Compression moulding of complex parts for the aerospace with discontinuous novel and recycled thermoplastic composite materials

International audienceThis development concerns the production of complex parts capable of withstanding concentrated loads with up to 84 % weight saving compared to metallic discontinuous thermoplastic composite materials

CE0713

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report.In the southwest of Ireland and the Celtic Sea (ICES Divisions VIIaS, g & j), herring are an important commercial species to the pelagic and polyvalent fleet. The local fleet is composed of dry hold polyvalent vessels and a small number of purpose built RSW (Refrigerated seawater) vessels. The stock is composed of both autumn and winter spawning components and the fishery targets pre-spawning and spawning aggregations. The Irish commercial fishery has historically taken place within 1-20nmi (nautical miles) of the coast and focused on aggregated schools within the spawning cycle. In recent years the larger RSW vessels have actively targeted offshore summer feeding aggregations in the south Celtic Sea. In VIIj, the fishery traditionally begins in early October and is concentrated within several miles of the shore including many bays and inlets. The VIIaS fishery peaks towards the year end in December, but may be active from mid October depending on location. In VIIg, along the south coast herring are targeted from October to January at a number of known spawning sites and surrounding areas. Overall, the protracted spawning period of the two components extends from October through to January, with annual variation of up to 3 weeks. Spawning occurs in successive waves in a number of well known locations including large scale grounds and small discreet spawning beds. The geographical confines of the annual 21 day survey have been modified in recent years to include areas to the south of the main winter spawning grounds in an effort to identify the whereabouts of winter spawning fish before the annual inshore spawning migration. Spatial resolution of acoustic transects has been increased over the entire south coast survey area. The acoustic component of the survey has been further complimented by detailed hydrographic and marine mammal and seabird work programs first initiated during this survey in 2004

Cavitation pressure in liquid helium

Recent experiments have suggested that, at low enough temperature, the homogeneous nucleation of bubbles occurs in liquid helium near the calculated spinodal limit. This was done in pure superfluid helium 4 and in pure normal liquid helium 3. However, in such experiments, where the negative pressure is produced by focusing an acoustic wave in the bulk liquid, the local amplitude of the instantaneous pressure or density is not directly measurable. In this article, we present a series of measurements as a function of the static pressure in the experimental cell. They allowed us to obtain an upper bound for the cavitation pressure P_cav (at low temperature, P_cav < -2.4 bar in helium 3, P_cav < -8.0 bar in helium 4). From a more precise study of the acoustic transducer characteristics, we also obtained a lower bound (at low temperature, P_cav > -3.0 bar in helium 3, P_cav > - 10.4 bar in helium 4). In this article we thus present quantitative evidence that cavitation occurs at low temperature near the calculated spinodal limit (-3.1 bar in helium 3 and -9.5 bar in helium 4). Further information is also obtained on the comparison between the two helium isotopes. We finally discuss the magnitude of nonlinear effects in the focusing of a sound wave in liquid helium, where the pressure dependence of the compressibility is large.Comment: 11 pages, 9 figure

North Western Waters Atlas 3rd Edition

The third edition of the North Western Waters (NWW) Atlas is a joint publication between the Marine Institute and the NWW Advisory Council. This Atlas is intended for policy makers, managers and interested stakeholders and aims to provide a broad overview of the ecosystem of the NWW Advisory Council (AC) area. We have tried to make the science as clear and concise as possible, and keep technical language to a minimum. The information has been presented through a blend of text, tables, figures and images. There is a glossary of terms and a list of more detailed scientific references for those interested in following up certain issues. The first and second editions of the Atlas, published in 2009 and 2011 respectively under the MEFEPO project, were extremely well received and this new edition has been modified in response to stakeholder feedback to provide updated information on the physical and chemical features, habitat types, biological features, birds, mammals, fishing activity and other human activities taking place within the NWW region. We have received valuable contributions from non-governmental organisations, which use citizen science to collect information on the marine ecosystem around us. Whenever citizen science is used to complement the existing knowledge, this is clearly marked in the relevant sections. The North Western Waters (NWW) area is situated in the north east Atlantic off the west coast of Ireland and Scotland, and extends into the Celtic Sea, Irish Sea and the English Channel.Funder: Marine Institut

CE0711

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report.The Marine Institute with the collaboration of the National University of Galway conducted a multidisciplinary deepwater survey along the continental slope of the Northeast Atlantic. At three selected sites northwest of Ireland and on the northern slopes of the Porcupine Bank, fishing transects were carried out at four depth strata (500m, 1000m 1500m and 1800m) during the day, while oceanographic measurements and plankton and benthic invertebrate sampling was carried out during the night. Data from CTD and ADCP measurements showed following distribution of water masses: The top 700 m was occupied by that of Eastern North Atlantic Water (ENAW) origin which is a basic feature of the upper layer hydrography in the Rockall Trough; small salinity maxima indicated the region associated with the core of the shelf edge current (SEC). At Area 6, immediately north of Porcupine Bank, a salinity maximum at a depth of 900-1000 m indicated the presence of Mediterranean Outflow Water (MOW) with the presence Labrador Sea Water (LSW) at 1800-2000 m. The SEC was identified in both CTD and ADCP transects and was characterised by a number of relatively narrow filaments evident in the salinity data. In terms of benthic invertebrate data, a total of 104 taxa were identified with a maximum number of 33 invertebrate taxa identified per haul (these values were recorded at two 1500m hauls in 2006 and 2007, in Areas 5 and 2, respectively). Overall, no clear relationship between the number of invertebrate species and depth was apparent, however there was some indication that the number of species appears to be more variable in deeper waters. Several species occurred in very large numbers; these were the echinoderms, Cidaris cidaris, Benthegone rosea and Stichopus tremulus and the bivalve, Pseudammusium septemradii. Fisheries data revealed distinct deepwater fish communities that changed with depth and to a lesser extent with area. The number of species increased with depth at all sites to reach a maximum at 1500m before decreasing again at 1800m. At 500m depth the fish community was mainly composed of rabbit fish and rattails with some shelf species present such as hake, ling and silver pout. The 1000m depth strata presented a transition of species composition. The most abundant species overall was Roundnose grenadier which had is highest abundance at 1500m in all three areas but could also be found in the 1000 and 18000m depth strata. Other species of high abundance which also had their highest number of individuals at 1500m were Baird’s smoothhead and other species of grenadiers. Cluster analysis revealed that Roundnose grenadier was a distinct species grouping as was that of Baird’s smoothhead. Species occurrences were similar in all three areas with some regional differences; in area 2, Phycis blennoides, greater forkbeard,occurred among the ten most abundant species while in area 5, species, such as Black Scabbard, Aphanopus carbo, and cut throat eel, Synaphobranchus kaupi, were being caught here in larger numbers while present in the other areas in low numbers. Seven comparative tows were carried out with the Scottish research vessels RV Scotia and indicated that overall similar numbers of species and total number of fish were caught. Size distribution also compared well between the two different vessels, however for some species the numbers or size ranges of fish caught differed

Validation of standard and alternative satellite ocean-color chlorophyll products off Western Iberia

Chlorophyll a concentration (Chl) product validation off theWestern Iberian coast is here undertaken by directly comparing remote sensing data with in situ surface reference values. Both standard and recently developed alternative algorithms are considered for match-up data analysis. The investigated standard products are those produced by the MERIS (algal 1 and algal 2) and MODIS (OC3M) algorithms. The alternative data products include those generatedwithin the CoastColour Project and Ocean Color Climate Change Initiative (OC-CCI) funded by ESA, as well as a neural net model trained with field measurements collected in the Atlantic off Portugal (MLPATLP). Statistical analyses showed that satellite Chl estimates tend to be larger than in situ reference values. The study also revealed that a non-uniform Chl distribution in the water column can be a concurring factor to the documented overestimation tendency when considering larger optical depth match-up stations. Among standard remote sensing products, MODIS OC3M and MERIS algal 2 yield the best agreement with in situ data. The performance of MLPATLP highlights the capability of regional solutions to further improve Chl retrieval by accounting for environmental specificities. Results also demonstrate the relevance of oceanographic regions such as the Nazaré area to evaluate how complex hydrodynamic conditions can influence the quality of Chl products.This studywas performed in the framework of HabSpot FCT Project, PTDC/MAR/100348/2008 and European Space Agency projects DUE CoastColour (ESRIN/AO/1-6141/09/l-EC) and Climate Change Iniciative — Ocean Color (AO-1/6207/09/I-LG). The work has been also partially supported by the European Space Agency within the framework of the MERIS Validation Activities under contract n. 12595/09/I-OL, and sampling activities benefited from European projects HERMES (GOCE-CT-2005-511234) and Hermione (EC contract 226354) support. We would like to thank NASA OBPG for the MODIS data and ESA Project AOPT-2423 for providing MERIS full resolution images. Ana C. Brito was funded by a Portuguese Post-doc grant from FCT (BPD/63017/2009) and by the Investigador FCT Program (IF/00331/2013). Davide D'Alimonte was funded by Investigador FCT Program (IF/00541/2013).info:eu-repo/semantics/publishedVersio