215 research outputs found

    Synthesis, characterization and performance of robust poison-resistant ultrathin film yttria stabilized zirconia – nickel anodes for application in solid electrolyte fuel cells

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    We report on the synthesis of undoped ∼5 μm YSZ-Ni porous thin films prepared by reactive pulsed DC magnetron sputtering at an oblique angle of incidence. Pre-calcination of the amorphous unmodified precursor layers followed by reduction produces a film consisting of uniformly distributed tilted columnar aggregates having extensive three-phase boundaries and favorable gas diffusion characteristics. Similarly prepared films doped with 1.2 at.% Au are also porous and contain highly dispersed gold present as Ni-Au alloy particles whose surfaces are strongly enriched with Au. With hydrogen as fuel, the performance of the undoped thin film anodes is comparable to that of 10–20 times thicker typical commercial anodes. With a 1:1 steam/carbon feed, the un-doped anode cell current rapidly falls to zero after 60 h. In striking contrast, the initial performance of the Au-doped anode is much higher and remains unaffected after 170 h. Under deliberately harsh conditions the performance of the Au-doped anodes decreases progressively, almost certainly due to carbon deposition. Even so, the cell maintains some activity after 3 days operation in dramatic contrast with the un-doped anode, which stops working after only three hours of use. The implications and possible practical application of these findings are discussed.European Union 298300Ministerio de Economía y Competitividad MAT2013‐40852R, 201560E05

    Study of Ce/Pr ratio in ceria-praseodymia catalysts for soot combustion under different atmospheres

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    The effect of Ce/Pr ratio on ceria-praseodymia on structural and surface properties is studied. The catalytic activity towards soot combustion under NOx/O2 and O2/N2 atmospheres is also evaluated, together with the NO oxidation activity to NO2. CexPr1-xO2-δ compositions (x = 0.8, 0.5 and 0.2) have been prepared along with ceria and praseodymia. Catalysts were prepared by co-precipitation. The Ce0.5Pr0.5O2-δ composition, was also prepared by nitrate calcination. Ceria-praseodymia mixed oxides yield reduction profiles shifted to lower temperatures, higher NO oxidation activities to NO2 and improved catalytic activities for soot combustion with respect to pure ceria. Ce0.5Pr0.5O2-δ was the most active one. Under NOx/O2, it has greater soot combustion activity if it is prepared by nitrate calcination. However, under O2/N2, the co-precipitation method is more favorable because of the better dopant insertion achieved in the ceria lattice, which seems to lead better oxygen mobility on the surface and in the bulk oxide.The authors gratefully acknowledge the financial support of Generalitat Valenciana (PROMETEO/2018/076 project) and the Spanish Ministry of Economy and Competitiveness (CTQ2015-64801-R project) and the UE-FEDER funding. J.C.M.M. also acknowledges Spanish Ministry of Science, Innovation and Universities for the financial support through a FPU grant (FPU17/00603)

    Green measures for Mediterranean harbours under a changing climate

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    Harbour operability may be hampered by climate change. Green solutions can be used to provide extra flexibility with respect to present grey infrastructure to adapt to, and mitigate, such functional disruptions with affordable costs. This paper assesses the performance of a green solution (a seagrass meadow) by assessing its effectiveness through numerical modelling. The analysis is carried out at two harbours that, under the present climate, are prone to wave agitation and overtopping problems. The efficiencies of different seagrass layouts are tested at both sites, by comparing the relevant hydrodynamic parameters. It is concluded that, for moderate sea level rise (SLR) rates, illustrated by the central trend of a medium scenario from the Intergovernmental Panel on Climate Change, the use of seagrass meadows would be effective enough to attenuate the impact of SLR on breakwater overtopping. In addition, the use of such measures could attenuate the increases in port agitation due to changes in wave direction caused by climate change. Nevertheless, the complexity of the interactions between hydrodynamics and seagrass would require periodic monitoring and re-evaluation to maintain acceptable risk levels, especially in case of extreme scenarios.Peer ReviewedPostprint (author's final draft

    Assessment of green measures as coastal defences using numerical models

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    Climate change may reduce the performance and design life of “grey” coastal engineering interventions. Green solutions can be combined with present infrastructures providing extra flexibility to adapt our present beaches with affordable costs. This paper assesses the behaviour of a typology of green solutions (seagrass meadows) via numerical hydro-morphodynamic modelling for an erosive beach prone to episodic flooding, under typical Mediterranean conditions. A multivariate method for jointly assessing flooding and erosion via copulas is proposed and developed. In the considered pilot site, different layouts have been tested by analysing their efficiency and limits. It is concluded that, for moderate SLR rates (RCP 4.5. central trend), these green measures could attenuate efficiently the expected changes in marine drivers. However, the complexity of eco-hydraulic interactions on which the Nature Based Solutions depend would demand periodic monitoring and evaluation for maintaining acceptable risk levels, especially in the case of high-end scenarios.Postprint (published version

    Retrospective analysis of cattle poisoning in Argentina (2000-2013)

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    A retrospective analysis (2000 to 2013) of cattle poisoning caused by toxic plants and other compounds was carried out in the Pampas region of Argentina by the Animal Health Group of INTA-EEA, Balcarce. During this period, 1263 reports of diseases of different etiologies (infectious, parasitic, toxic, metabolic and miscellaneous) were recorded in cattle, by collecting anamnestic, clinical and pathological information. A toxic etiology was diagnosed in 21.1% of these reports. Iatrogenic poisoning caused by ionophores was the most frequently recorded etiology. Consumption of toxic plants (Wedelia glauca, Solanum glaucophyllum, among others), mycotoxins (Claviceps purpurea, Claviceps paspali, Epichloë coenophiala, among others), and plants producing cyanide and nitrates/nitrites were also commonly diagnosed. The high frequency of toxic episodes and the difficulties in their diagnosis by practitioners in our livestock production systems emphasizes the importance of this report.EEA BalcarceFil: García, Juan Agustín. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Canton, German Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Spath, Ernesto Juan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Odriozola, Ernesto Raul. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Garcia, Bernardo L. Actividad Privada; ArgentinaFil: Micheloud, Juan Francisco. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Campero, Carlos Manuel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentin

    PIMA Adapta Costas, a characterisation of flooding and erosion under different climate change scenarios along the Catalan coast

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    Climate change, with sea level rise as one of its main consequences, will heavily change the dynamics of the coast in the next years. The assessment of the impacts that could cause is a key issue to anticipate measures and reduce risks, mainly flooding and erosion. PIMA Adapta Costas is a national project financed by “Ministerio de Transicion Ecológica y el Reto Demográfico” which aims to answer these unknowns along the Spanish coast. This work presents the evaluation of such impacts in 54 Catalan beaches located in 8 littoral cells. Erosion has been characterized by tracking the retreat of different datums whereas flooding has been defined as the sum of all inundated areas during more than 4 hours. The obtained results are integrated in a specific viewer developed by the ICGC. A complete description of the impacts will help identifying common response patterns that can be used to select optimal management strategies to reduce risks.Postprint (published version

    Sistemes costaners i dinàmica litoral

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    Aquest capítol tracta de la projecció dels impactes de climes futurs per a trams vulnerables de la costa catalana. Al començament, s’hi revisa la geodiversitat de la costa en termes meteorològics i geològics. El ventall d’impactes que en resulta (sota climes presents i futurs) presenta uns nivells d’incertesa que s’han de considerar per a poder prendre decisions. L’anàlisi es basa en les projeccions del nivell mitjà del mar i en les característiques de l’onatge per a les famílies d’escenaris RCP (trajectòries de concentracions representatives). La projecció dels impactes d’erosió i inundació per a platges i d’agitació i ultrapassament per a ports permet determinar quin és el domini costaner sotmès a aquests impactes, i també quins seran els nivells de risc que es poden esperar en platges i ports. Les conclusions del capítol s’estructuren com un seguit d’actuacions seqüencials per a afavorir la sostenibilitat de la costa. Aquest «camí d’adaptació» permetrà d’assolir uns nivells de riscs presents i futurs explícits, que han de ser considerats per a les activitats socioeconòmiques de la zona litoral.Postprint (published version

    Present and future flooding and erosion along the NW Spanish Mediterranean Coast

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    Coastal flooding and eros-ion caused by extreme events are the main factors responsible for beach hazards. This effect will be exacerbated by the sea level rise induced by climate change. The present work determines the vulnerability to erosion and flooding along 55 beaches grouped in different coastal archetypes, representative of the Catalan coast. The vulnerability assessment has been done through the numerical simulation of different combinations for projected waves and mean water levels under present conditions and the climate change scenarios RCP4.5 and RCP8.5 for the year 2100. A storm event approach has been used to determine coastal flooding and erosion with return periods of 50, 100, and 500 years using the XBeach numerical model. Results show that shoreline retreat is not the best proxy to characterize the erosion. The low-lying nature of the coast, the non-presence of well-developed berms, and the existence of river mouth and torrents govern the coastal flooding. The sea level rise appears to be a dominant variable in coastal hazards.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 101037097 (REST-COAST project).Peer ReviewedPostprint (published version

    Squamous cell carcinoma in small ruminants from Argentinian Patagonia

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    Se describen las características clínicas y anatomopatológicas de casos de carcinoma de células escamosas (CCE) en tres pequeños rumiantes, dos ovinos Merino y un caprino Angora en Argentina. Macroscópicamente, los animales presentaban masas protuberantes de aspecto verrucoso ubicados en la región palpebral, nasal, preescapular y pre-crural. El estudio histológico reveló proliferación local de células neoplásicas características del CCE, hallándose diferentes tipos: bien diferenciado, moderadamente diferenciado y pobremente diferenciado. Si bien la enfermedad es escasamente reportada en Argentina, su ocurrencia establece la necesidad de considerarla como diagnóstico diferencial en enfermedades de la piel y faneras de los pequeños rumiantes.The clinical and anatomopathological features of cases of squamous cell carcinoma (SCC) were described in three small ruminants, two Merino sheep and one Angora goat in Argentina. Macroscopically, protruding warty masses located in the palpebral, nasal, pre-scapular and pre-crural regions were observed. The histological study showed local proliferation of neoplastic cells characteristic of SCC with different subtypes including well-differentiated, moderately differentiated and poorly differentiated. Although the disease is scarcely reported in Argentina, it is proposed to consider it as a differential diagnosis of other skin diseases of small ruminants.Estación Experimental Agropecuaria BarilocheFil: Cucullu, Gaspar. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Área de Producción Animal. Grupo de Sanidad Animal; ArgentinaFil: Massone, Adriana. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias. Laboratorio de Patología Especial Veterinaria; ArgentinaFil: Garcia, Juan Agustín. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Consejo Nacional de Investigacines Científicas y Técnicas; ArgentinaFil: Robles, Carlos Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Area de Produccion Animal. Grupo de Sanidad Animal; ArgentinaFil: Martinez, Agustin. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Área Producción Animal. Grupo Sanidad Animal; Argentin

    Molecular elucidation of CO2 methanation over a highly active, selective and stable LaNiO3/CeO2-derived catalyst by in situ FTIR and NAP-XPS

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    The CO2 methanation mechanism over the highly active (TOF=75.1 h−1), selective (>92%) and stable 10% LaNiO3/CeO2-derived catalyst is still unresolved. The surface of the catalyst is monitored under hydrogenation (H2), oxidizing (CO2) and CO2 methanation (H2 +CO2) conditions by near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) using synchrotron radiation. Meanwhile, the main reaction intermediates are identified by in situ FTIR analysis. NAP-XPS experiments confirm that LaNiO3 perovskite reduction leads to the ex-solution of Ni0 nanoparticles and Ni2+single bondCeO2−x and Ni2+single bondLa2O3 interfaces conformation, favouring the CO2 adsorption and the H2 dissociation/transfer. In situ FTIR experiments combined with the C1s spectra (NAP-XPS) suggest that the CO2 activation occurs on CeO2−x (oxygen vacancies and OH–) at low temperatures, in the form of bicarbonates; whereas, mono-/bidentate carbonates are formed on different strength La2O3 sites at increasing temperatures. These species are consecutively reduced to formates, as the main reaction intermediate, and methane by the H spilled from Ni0 nanoparticles near to NiOsingle bondCeO2−x and NiOsingle bondLa2O3 interfaces.Support for this study was provided by Projects PID2019–105960RB-C21 and PID2019–105960RB-C22 by MCIN/AEI/10.13039/501100011033, the Basque Government (Project IT1509–2022), Generalitat Valenciana (CIPROM/2021/74) and ALBA synchrotron. One of the authors (JAOC) acknowledges the postdoctoral research grant (DOCREC20/49) provided by the University of the Basque Country (UPV/EHU)
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