Search results for "Location"

showing 10 items of 1480 documents

Trapping of hydrogen and helium at dislocations in tungsten: anab initiostudy

2017

Retention of plasma gas components such as hydrogen (H) isotopes and helium (He) is one of the limiting factors in selection of plasma facing materials for future thermonuclear fusion devices. Tungsten (W) is one of the promising candidates for such materials and was chosen for the divertor armor for International Thermonuclear Experimental Reactor (ITER) and the first wall material for the design of the demonstrational fusion power plant - DEMO. For the analytical estimation of accumulation of H/He components in tungsten, it is important to understand the relevant physical mechanisms of their trapping in the material and thoroughly parameterize them numerically. Experiments involving high …

Nuclear and High Energy PhysicsMaterials sciencetungstenH and He in Wtrapping at dislocationAb initiohelium02 engineering and technologyDFT7. Clean energy01 natural sciences010305 fluids & plasmasCondensed Matter::Materials ScienceAb initio quantum chemistry methodsVacancy defect0103 physical sciencesAtomPhysics::Atomic PhysicsplasmaEmbedded atom modelab initiomolecular staticsCharge density021001 nanoscience & nanotechnologyCondensed Matter Physics13. Climate actionhydrogenDislocationAtomic physics0210 nano-technologyBurgers vectordislocationsNuclear Fusion
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Formation of dislocations in LiF irradiated with 3He and 4He ions

2018

Influence of the irradiation with 13.5 MeV 3He and 5 MeV 4He ions on the micro-structure and mechanical properties of LiF single crystals was studied. The depth profiles of nanoindentation, dislocation mobility, selective chemical etching and photoluminescence served for the characterization of damage. Strong ion-induced increase of hardness and decrease in dislocation mobility at the stage of track overlapping due to accumulation of dislocations and other extended defects was observed. At high fluences (1015 ions/cm2) the hardness saturates at about 3.5 GPa (twofold increase in comparison to a virgin crystal) thus confirming high efficiency of light projectiles in modifications of structur…

Nuclear and High Energy PhysicsPhotoluminescenceMaterials scienceIon-irradiation3He and 4He ionsDislocations02 engineering and technology01 natural sciencesMolecular physicsNanoindentationIonCrystal0103 physical sciences:NATURAL SCIENCES:Physics [Research Subject Categories]General Materials ScienceIrradiation010306 general physicsPhotoluminescenceLiF crystalsNanoindentationDamage beyond the ion range021001 nanoscience & nanotechnologyIsotropic etchingCharacterization (materials science)Nuclear Energy and EngineeringDislocation0210 nano-technologyJournal of Nuclear Materials
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A fast dual boundary element method for 3D anisotropic crack problems

2009

In the present paper a fast solver for dual boundary element analysis of 3D anisotropic crack problems is formulated, implemented and tested. The fast solver is based on the use of hierarchical matrices for the representation of the collocation matrix. The admissible low rank blocks are computed by adaptive cross approximation (ACA). The performance of ACA against the accuracy of the adopted computational scheme for the evaluation of the anisotropic kernels is investigated, focusing on the balance between the kernel representation accuracy and the accuracy required for ACA. The system solution is computed by a preconditioned GMRES and the preconditioner is built exploiting the hierarchical …

Numerical AnalysisMathematical optimizationCollocationRank (linear algebra)PreconditionerApplied MathematicsGeneral EngineeringDegrees of freedom (statistics)SolverGeneralized minimal residual methodMatrix (mathematics)Applied mathematicsBoundary element methodMathematicsInternational Journal for Numerical Methods in Engineering
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Exponential convergence andH-c multiquadric collocation method for partial differential equations

2003

The radial basis function (RBF) collocation method uses global shape functions to interpolate and collocatethe approximate solution of PDEs. It is a truly meshless method as compared to some of the so-calledmeshless or element-free finite element methods. For the multiquadric and Gaussian RBFs, there are twoways to make the solution converge—either by refining the mesh size

Numerical AnalysisRegularized meshless methodPartial differential equationApplied MathematicsGaussianMathematical analysisResidualSingular boundary methodComputational Mathematicssymbols.namesakeCollocation methodsymbolsOrthogonal collocationRadial basis functionAnalysisMathematicsNumerical Methods for Partial Differential Equations
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Seawater carbonate chemistry and shell mineralogy, microstructure, and mechanical strength of four Mediterranean gastropod species near a CO2 seep

2017

Marine CO2 seeps allow the study of the long-term effects of elevated pCO2 (ocean acidification) on marine invertebrate biomineralization. We investigated the effects of ocean acidification on shell composition and structure in four ecologically important species of Mediterranean gastropods (two limpets, a top-shell snail, and a whelk). Individuals were sampled from three sites near a volcanic CO2 seep off Vulcano Island, Italy. The three sites represented ambient (8.15 pH), moderate (8.03 pH) and low (7.73 pH) seawater mean pH. Shell mineralogy, microstructure, and mechanical strength were examined in all four species. We found that the calcite/aragonite ratio could vary and increased sign…

Ocean Acidification International Coordination Centre (OA-ICC)IdentificationRegistration number of speciesSalinityTemperateinorganicAlkalinityExperimentTemperature waterCarbon inorganic dissolvedCalculated using seacarb after Nisumaa et al 2010Aragonite saturation stateAlkalinity totalSalinity standard errorPatella caeruleatotalCO2 ventpHCalciteTemperaturePartial pressure of carbon dioxide (water) at sea surface temperature (wet air) standard errordissolvedCarbonate ionPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)standard errorEarth System ResearchField observationUniform resource locator link to referencePotentiometric titrationCalcite saturation stateLengthLocationPotentiometricwaterGrowth MorphologyHexaplex trunculusAlkalinity total standard errorBenthosUniform resource locator/link to referenceOsilinus turbinatusOther studied parameter or processMediterranean SeaOcean Acidification International Coordination Centre OA ICCAnimaliaBicarbonate ionTypeTemperature water standard errorCalculated using seacarb after Nisumaa et al. (2010)ForceSpeciespH standard errorCalculated using CO2SYSCarbonate system computation flagFugacity of carbon dioxide (water) at sea surface temperature (wet air)CarbonElasticityTreatmentAragonite saturation state standard errorPartial pressure of carbon dioxide water at sea surface temperature wet airAragoniteCarbon dioxideMolluscaGrowth/MorphologySingle speciesBenthic animalsFugacity of carbon dioxide water at sea surface temperature wet airPatella rusticaToughnessCoast and continental shelf
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Seawater carbonate chemistry and kelp densities and coral coverages at three study locations and photosynthesis and calcification of corals measured …

2021

Ocean warming is altering the biogeographical distribution of marine organisms. In the tropics, rising sea surface temperatures are restructuring coral reef communities with sensitive species being lost. At the biogeographical divide between temperate and tropical communities, warming is causing macroalgal forest loss and the spread of tropical corals, fishes and other species, termed “tropicalization”. A lack of field research into the combined effects of warming and ocean acidification means there is a gap in our ability to understand and plan for changes in coastal ecosystems. Here, we focus on the tropicalization trajectory of temperate marine ecosystems becoming coral-dominated systems…

Ocean Acidification International Coordination Centre (OA-ICC)Net calcification rate of calcium carbonate lightCommunity composition and diversityAlkalinity total standard deviationunique identificationTemperature waterCarbon inorganic dissolvedNet calcification rate of calcium carbonateCalculated using seacarb after Nisumaa et al 2010Color descriptionRespiration rate oxygenpHRespirationMonthCarbonate ionLaboratory experimentField experimentRespiration rateunique identification URIstandard deviationlightAcropora solitaryensisCalcification/DissolutionCalcite saturation statewaterPartial pressure of carbon dioxideSiteGrowth MorphologyRocky-shore communityAragonite saturation state standard deviationPorites heronensisCarbon inorganic dissolved standard deviationTypeCalculated using seacarb after Nisumaa et al. (2010)Primary production PhotosynthesisSpeciesBottles or small containers/Aquaria (&lt;20 L)fungiEvent labeltechnology industry and agricultureCarbonate system computation flagpH standard deviationbiochemical phenomena metabolism and nutritionFugacity of carbon dioxide (water) at sea surface temperature (wet air)CarbonPartial pressure of carbon dioxide water at sea surface temperature wet airEntire communitySingle speciesCalcification DissolutionBenthic animalsFugacity of carbon dioxide water at sea surface temperature wet airCoralCoast and continental shelfPhotosynthetic efficiencySpecies unique identification (URI)darkIdentificationRegistration number of speciesSalinityTemperateBottles or small containers/Aquaria (<20 L)inorganicAlkalinityArea localityNet photosynthesis rate oxygenExperimentArea/localityAragonite saturation stateNorth PacificAlkalinity totalBottles or small containers Aquaria 20 LtotalCO2 ventCalcification rate of calcium carbonateTemperaturedissolvedPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)Temperature water standard deviationNet photosynthesis rateEarth System ResearchNet calcification rate of calcium carbonate darkField observationgeographic locationsSpecies unique identificationBenthosCnidariaDiameterOcean Acidification International Coordination Centre OA ICCAnimaliaBicarbonate ionGrowth ratePartial pressure of carbon dioxide standard deviationPrimary production/PhotosynthesisTreatmentCarbon dioxideGrowth/MorphologyRocky shore communityShootsoxygen
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Ocean acidification impairs vermetid reef recruitment

2014

Vermetids form reefs in sub-tropical and warm-temperate waters that protect coasts from erosion, regulate sediment transport and accumulation, serve as carbon sinks and provide habitat for other species. The gastropods that form these reefs brood encapsulated larvae; they are threatened by rapid environmental changes since their ability to disperse is very limited. We used transplant experiments along a natural CO2 gradient to assess ocean acidification effects on the reef-building gastropod Dendropoma petraeum. We found that although D. petraeum were able to reproduce and brood at elevated levels of CO2, recruitment success was adversely affected. Long-term exposure to acidified conditions…

Ocean Acidification International Coordination Centre (OA-ICC)SalinityTemperateSurvivalAbundance per areainorganicAlkalinityIncubation durationExperimentTemperature waterCarbon inorganic dissolvedNeogoniolithon brassica-floridaCalculated using seacarb after Nisumaa et al 2010Aragonite saturation stateAlkalinity totalSalinity standard errortotalCO2 ventMortality SurvivalpHReproductionTemperaturePartial pressure of carbon dioxide (water) at sea surface temperature (wet air) standard errorStrontium/Calcium ratiodissolvedMagnesium/Calcium ratioCarbonate ionPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)Field experimentstandard errorEarth System ResearchRecruitmentMortality/SurvivalFOS: Medical biotechnologygeographic locationsPotentiometric titrationCalcite saturation stateCoveragePotentiometricwaterSiteGrowth MorphologyFigureAlkalinity total standard errorBenthosReplicateMediterranean SeaOcean Acidification International Coordination Centre OA ICCAnimaliaBicarbonate ionNeogoniolithon brassica floridaLONGITUDETemperature water standard errorCalculated using seacarb after Nisumaa et al. (2010)SpeciespH standard errorCalculated using CO2SYSfungiCarbonate system computation flagFugacity of carbon dioxide (water) at sea surface temperature (wet air)CarbonAragonite saturation state standard errorPartial pressure of carbon dioxide water at sea surface temperature wet airCarbon dioxideMolluscaGrowth/MorphologySingle speciesLATITUDEBenthic animalsFugacity of carbon dioxide water at sea surface temperature wet airMagnesium Calcium ratioCoast and continental shelfDendropoma petraeumStrontium Calcium ratio
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Seawater carbonate chemistry and percentage cover of macroalgal species at three locations at Vulcano, Italy

2017

Beneficial effects of CO2 on photosynthetic organisms will be a key driver of ecosystem change under ocean acidification. Predicting the responses of macroalgal species to ocean acidification is complex, but we demonstrate that the response of assemblages to elevated CO2 are correlated with inorganic carbon physiology. We assessed abundance patterns and a proxy for CO2:HCO3- use (delta 13C values) of macroalgae along a gradient of CO2 at a volcanic seep, and examined how shifts in species abundance at other Mediterranean seeps are related to macroalgal inorganic carbon physiology. Five macroalgal species capable of using both HCO3- and CO2 had greater CO2 use as concentrations increased. Th…

Ocean Acidification International Coordination Centre (OA-ICC)TemperateRegistration number of speciesSalinityCaulerpa proliferaCommunity composition and diversityBicarbonate ion standard deviationUdotea petiolatainorganicAlkalinity total standard deviationAlkalinitySargassum muticumDictyota dichotomaHalopteris scopariaYearsCystoseira brachycarpaExperimentTemperature waterCarbon inorganic dissolvedCystoseira foeniculaceaCaulerpa racemosaCalculated using seacarb after Nisumaa et al 2010Cystoseira foeniculataAragonite saturation stateAlkalinity totaltotalCO2 ventpHTemperaturedissolvedCarbonate ionPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)Acetabularia acetabulumJania rubensCarbon dioxide standard deviationEarth System Researchδ13CLipid contentstandard deviationField observationUniform resource locator link to referenceCystoseira crinitaCoverageCalcite saturation stateLocationwaterSiteRocky-shore communityFigureBenthosUniform resource locator/link to referenceOcean Acidification International Coordination Centre OA ICCMediterranean SeaCarbon inorganic dissolved standard deviationTypeBicarbonate ionDictyopteris polypodioidesDilophus fasciolaCalculated using seacarb after Nisumaa et al. (2010)SpeciesCystoseira compressaEvent labelCarbonate system computation flagpH standard deviationCarbonate ion standard deviationMassFugacity of carbon dioxide (water) at sea surface temperature (wet air)CarbonOxygenPartial pressure of carbon dioxide water at sea surface temperature wet airCarbon dioxideRocky shore communityEntire communityFugacity of carbon dioxide water at sea surface temperature wet airPadina pavonicaSeasonδ13C standard deviationCoast and continental shelfCodium bursaTableCystoseira barbarta
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Seawater carbonate chemistry and fish communities properties off CO2 seeps in Japan

2020

Ocean acidification will likely change the structure and function of coastal marine ecosystems over coming decades. Volcanic carbon dioxide seeps generate dissolved CO2 and pH gradients that provide realistic insights into the direction and magnitude of these changes. Here, we used fish and benthic community surveys to assess the spatio-temporal dynamics of fish community properties off CO2 seeps in Japan. Adding to previous evidence from ocean acidification ecosystem studies conducted elsewhere, our findings documented shifts from calcified to non-calcified habitats with reduced benthic complexity. In addition, we found that such habitat transition led to decreased diversity of associated …

Ocean Acidification International Coordination Centre (OA-ICC)TemperateSalinityCanopy heightCommunity composition and diversityCoverage standard deviationinorganicAlkalinityExperimentTemperature waterCarbon inorganic dissolvedCalculated using seacarb after Nisumaa et al 2010Aragonite saturation stateNorth PacificAlkalinity totaltotalCO2 ventReplicatespHPelagosTemperaturedissolvedCanopy height standard deviationCarbonate ionPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)Fish standard deviationTemperature water standard deviationEarth System Researchstandard deviationField observationgeographic locationsPotentiometric titrationCoverageCalcite saturation stateLocationPotentiometricwaterPartial pressure of carbon dioxideSiteRocky-shore communityBenthosSpecies richness standard deviationSalinity standard deviationOcean Acidification International Coordination Centre OA ICCBiotic Habitat Profile ratioTypeBicarbonate ionCalculated using seacarb after Nisumaa et al. (2010)Calculated using CO2SYSfungiPartial pressure of carbon dioxide standard deviationCarbonate system computation flagpH standard deviationFugacity of carbon dioxide (water) at sea surface temperature (wet air)CarbonPartial pressure of carbon dioxide water at sea surface temperature wet airFishTransectCarbon dioxideRocky shore communityEntire communityBiotic Habitat Profile ratio standard deviationFugacity of carbon dioxide water at sea surface temperature wet airSeasonCoast and continental shelfSpecies richness
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Seawater carbonate chemistry and coralline algal diversity

2021

Calcified coralline algae are ecologically important in rocky habitats in the marine photic zone worldwide and there is growing concern that ocean acidification will severely impact them. Laboratory studies of these algae in simulated ocean acidification conditions have revealed wide variability in growth, photosynthesis and calcification responses, making it difficult to assess their future biodiversity, abundance and contribution to ecosystem function. Here, we apply molecular systematic tools to assess the impact of natural gradients in seawater carbonate chemistry on the biodiversity of coralline algae in the Mediterranean and the NW Pacific, link this to their evolutionary history and …

Ocean Acidification International Coordination Centre (OA-ICC)TemperateSalinityCommunity composition and diversityBicarbonate ion standard deviationinorganicAlkalinity total standard deviationAlkalinityExperimentTemperature waterCarbon inorganic dissolvedCalculated using seacarb after Nisumaa et al 2010Aragonite saturation stateNorth PacificMarine habitatAlkalinity totaltotalCO2 ventpHTemperaturedissolvedCarbonate ionPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)Calcium carbonate standard deviationstandard errorEarth System Researchstandard deviationField observationCalcium carbonateCoverageCalcite saturation stateLocationwaterPartial pressure of carbon dioxideSiteRocky-shore communityCalcium carbonate massAragonite saturation state standard deviationBenthosSalinity standard deviationOcean Acidification International Coordination Centre OA ICCMediterranean SeaCarbon inorganic dissolved standard deviationCalcite saturation state standard deviationTypeBicarbonate ionCalculated using seacarb after Nisumaa et al. (2010)Coverage standard errorfungiEvent labelPartial pressure of carbon dioxide standard deviationCarbonate system computation flagpH standard deviationCarbonate ion standard deviationFugacity of carbon dioxide (water) at sea surface temperature (wet air)CarbonPartial pressure of carbon dioxide water at sea surface temperature wet airCarbon dioxideRocky shore communityEntire communityFugacity of carbon dioxide water at sea surface temperature wet airCoast and continental shelfSpecies richness
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