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

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

Gapless Hamiltonians for the toric code using the PEPS formalism

We study Hamiltonians which have Kitaev's toric code as a ground state, and show how to construct a Hamiltonian which shares the ground space of the toric code, but which has gapless excitations with a continuous spectrum in the thermodynamic limit. Our construction is based on the framework of Projected Entangled Pair States (PEPS), and can be applied to a large class of two-dimensional systems to obtain gapless "uncle Hamiltonians".Comment: 8 pages, 2 figure

Neutrinos and the matter-antimatter asymmetry in the Universe

The discovery of neutrino oscillations provides a solid evidence for nonzero neutrino masses and leptonic mixing. The fact that neutrino masses are so tiny constitutes a puzzling problem in particle physics. From the theoretical viewpoint, the smallness of neutrino masses can be elegantly explained through the seesaw mechanism. Another challenging issue for particle physics and cosmology is the explanation of the matter-antimatter asymmetry observed in Nature. Among the viable mechanisms, leptogenesis is a simple and well-motivated framework. In this talk we briefly review these aspects, making emphasis on the possibility of linking neutrino physics to the cosmological baryon asymmetry originated from leptogenesis.Comment: 8 pages, 1 table, 1 figure; Based on talk given at the Symposium STARS2011, 1 - 4 May 2011, Havana, Cuba; to be published in the Proceeding

High performance novel gadolinium doped ceria/yttria stabilized zirconia/nickel layered and hybrid thin film anodes for application in solid oxide fuel cells

Magnetron sputtering under oblique angle deposition was used to produce Ni-containing ultra thin film anodes comprising alternating layers of gadolinium doped ceria (GDC) and yttria stabilized zirconia (YSZ) of either 200 nm or 1000 nm thickness. The evolution of film structure from initial deposition, through calcination and final reduction was examined by XRD, SEM, TEM and TOF-SIMS. After subsequent fuel cell usage, the porous columnar architecture of the two-component layered thin film anodes was maintained and their resistance to delamination from the underlying YSZ electrolyte was superior to that of corresponding single component Ni-YSZ and Ni-GDC thin films. Moreover, the fuel cell performance of the 200 nm layered an- odes compared favorably with conventional commercially available thick anodes. The observed dependence of fuel cell performance on individual layer thicknesses prompted study of equivalent but more easily fabricated hybrid anodes consisting of simultaneously deposited Ni-GDC and Ni-YSZ, which procedure resulted in exceptionally intimate mixing and interaction of the components. The hybrids exhibited very unusual and favorable I---V characteristics, along with exceptionally high power densities at high currents. Their discovery is the principal contribution of the present work.European Union's Seventh Framework Programme FP7/2007–2013Fuel Cells and Hydrogen Joint Technology Initiative under the T-CELL project, grant 298300MINECO (Spain), grants nº MAT2013-40852RJuan de la Cierva Programme FPDI-2013-1862

Climate Change-induced Effects on Beach Degradation and Tourist Behaviour: A review of previous studies with potential in an island tourism context

This article conducts a qualitative meta-analysis of papers addressing the topic of climate change impacts on beach loss and degradation, and its relation to tourist behaviour (destination choice, willingness to re-visit, expenditure and willingness to pay). The main aim is to identify values that can be used in future research works in the context of island tourism. We found that the strong specialisation and fragmentation of data and methods limit the transferability potential of previous research analysing climate-induced effects on beaches and tourist behaviour. Researchers from different fields bring their own conceptual models which often address similar problems but use different lenses and measurement units. Among the available studies, the ones with usable potential in a value transfer context are related to willingness to pay for adaptation measures. Overall, findings confirm that a greater transparency in the methodologies used to elicit values and a multidisciplinary approach are needed to ensure a more sustainable use of the information in order to fill knowledge gaps that still hinder the study of climate change

Water pricing: are 'polluters' paying the environmental costs of flow regulation?

River ecosystems are severely affected by dams and reservoirs. The Water Framework Directive states that polluters should be financially responsible for the caused environmental damage. Nevertheless, the environmental costs associated to flow regulation often are not fully paid by water users. This study presents an approach to value the environmental costs of flow regulation based on the "polluter pays" principle, i.e., the amount to be paid should be proportional to the caused environmental impact. The procedure includes three major steps: (i) assessing the admissible range of regulated flow variability based on flow data during the pre-dam period, (ii) estimating the daily environmental impact of regulated flows according to the resulting hydrological change in terms of the intensity, duration and frequency of the impact, and (iii) calculating the environmental costs of flow regulation subject to spatiotemporal characteristics. This paper applies the proposed methodology in the Luna River, Spain. The advantages over other water cost valuation methodologies are discussed. The approach enlarges the current recognition of water environmental costs and represents a simple and practical management tool for achieving the objectives of the Water Framework Directive

Generation of a BAC-based physical map of the melon genome

13 páginas, 4 figuras, 3 tablas.[Background]: Cucumis melo (melon) belongs to the Cucurbitaceae family, whose economic importance among horticulture crops is second only to Solanaceae. Melon has high intra-specific genetic variation, morphologic diversity and a small genome size (450 Mb), which make this species suitable for a great variety of molecular and genetic studies that can lead to the development of tools for breeding varieties of the species. A number of genetic and genomic resources have already been developed, such as several genetic maps and BAC genomic libraries. These tools are essential for the construction of a physical map, a valuable resource for map-based cloning, comparative genomics and assembly of whole genome sequencing data. However, no physical map of any Cucurbitaceae has yet been developed. A project has recently been started to sequence the complete melon genome following a whole-genome shotgun strategy, which makes use of massive sequencing data. A BAC-based melon physical map will be a useful tool to help assemble and refine the draft genome data that is being produced. [Results]: A melon physical map was constructed using a 5.7 × BAC library and a genetic map previously developed in our laboratories. High-information-content fingerprinting (HICF) was carried out on 23,040 BAC clones, digesting with five restriction enzymes and SNaPshot labeling, followed by contig assembly with FPC software. The physical map has 1,355 contigs and 441 singletons, with an estimated physical length of 407 Mb (0.9 × coverage of the genome) and the longest contig being 3.2 Mb. The anchoring of 845 BAC clones to 178 genetic markers (100 RFLPs, 76 SNPs and 2 SSRs) also allowed the genetic positioning of 183 physical map contigs/singletons, representing 55 Mb (12%) of the melon genome, to individual chromosomal loci. The melon FPC database is available for download at http://melonomics.upv.es/static/files/public/physical_map/ webcite. [Conclusions]: Here we report the construction of the first physical map of a Cucurbitaceae species described so far. The physical map was integrated with the genetic map so that a number of physical contigs, representing 12% of the melon genome, could be anchored to known genetic positions. The data presented is already helping to improve the quality of the melon genomic sequence available as a result of a project currently being carried out in Spain, adopting a whole genome shotgun approach based on 454 sequencing data.This project was funded by the Plan Nacional de Investigación Científica of the Spanish Ministerio de Educación y Ciencia (Project BIO2007-61789) and by the Consolider-Ingenio 2010 Programme of the Spanish Ministerio de Ciencia e Innovación (CSD2007-00036 "Center for Research in Agrigenomics").Peer reviewe

Influence of preparation procedures on the phenolic content, antioxidant and antidiabetic activities of green and black teas

The influence of common tea preparation procedures (temperature, infusion time, consumption time interval and tea bag/loose-leaf) and the type of water used, on the total phenolic content (TPC), the radical scavenging activity and the alpha-glucosidase inhibitory activity were assessed. Higher TPC and antioxidant activity were obtained when using lower mineralized waters. Tea bags also evidenced higher antioxidant activity than loose-leaf samples. Under the same conditions (90 degrees C and five minutes of infusion time) green tea contains almost twice the quantity of polyphenols and the free radical scavenging ability of black tea. In the alpha-glucosidase assay all infusions were active (97-100 %). Furthermore, HPLC allowed to identify some of the polyphenols present in both teas and to monitor their composition change with time. After twenty-four hours, the antioxidant activity was maintained without significant changes, but a small decrease in enzyme inhibition was observed, although this activity was still very high.info:eu-repo/semantics/publishedVersio