111 research outputs found

    A comparison between fine-grained and nanocrystalline electrodeposited Cu-Ni films. Insights on mechanical and corrosion performance

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    This is the author's version of a work that was accepted for publication in Surface & coating technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Surface & coating technology, Vol. 205, Núm. 23-24 (Sep 2011), p. 2585-5293 DOI 10.1016/j.surfcoat.2011.05.047Cu1−x-Nix (0.43 ≤ x ≤ 1.0) films were electrodeposited from citrate-sulphate baths at different current densities onto Cu/Ti/Si (100) substrates with the addition of saccharine as a grain-refining agent. The Cu-Ni alloy films produced from saccharine-free baths were fine-grained (crystallite size of ~400 nm). The addition of saccharine to the electrolytic solution induced a dramatic decrease in crystal size (down to ~27 nm) along with a reduction in surface roughness. Although the effect of saccharine on pure Ni films was less obvious, significant changes were observed due to the presence of saccharine in the bath during the alloying of Cu with Ni. Compared to fine-grained Cu-Ni films, the nanocrystalline films exhibited lower microstrains and a larger amount of stacking faults as observed by X-ray diffraction. These features enhance the mechanical properties of the Cu-Ni alloys, making the nanocrystalline Cu-Ni films superior to both the corresponding fine-grained films and pure Ni films. In particular, hardness in fine-grained films varied from 4.2 (x=0.43) to 5.4 GPa (x=0.86), whereas hardness varied between 6.7 and 8.2 GPa for nanocrystalline films of similar composition. In addition, wear resistance and elastic recovery were enhanced. Nanostructuring did not significantly affect corrosion resistance of Cu-Ni alloys in chloride media. Although the corrosion potential shifted slightly towards more negative values, the corrosion current density decreased, thereby making the electrodeposition nanostructuring process an effective tool to improve the overall properties of the Cu-Ni system

    Localized electrochemical deposition of porous Cu-Ni microcolumns: insights into the growth mechanisms and the mechanical performance

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    Cu-rich Cu-Ni alloy microcolumns (11-35 at% Ni) with large porosity degree were grown by localized electrochemical deposition (LECD) at voltages of 6.5 and 7.0 V. In turn, conventional electrodeposition was used to deposit fully-compact Cu-Ni films with analogous Ni/Cu ratios from a similar citrate-containing electrolytic solution. The localized supply rate of the predominant Cu(II) and Ni(II) electroactive species in the LECD microregion was calculated assuming both large and small concentration gradients. A shortage of Cu(II) at the cathode surface is mainly responsible for the development of porosity in the microcolumns, which directly affects mechanical performance, specifically nanoindentation hardness and Young's modulus. From nanoindentation experiments, a relative microcolumn density ranging between 14 and 20% was determined. These values indicate the current efficiency of the LECD process and can be used to calculate the consumption rates associated with metal cation electroreduction

    Tailoring the physical properties of electrodeposited CoNiReP alloys with large Re content by direct, pulse, and reverse pulse current techniques

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    This is the author's version of a work that was accepted for publication in Electrochimica acta. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Electrochimica acta, [96,(2013)] DOI10.1016/j.electacta.2013.02.077)The composition, surface morphology and structure of CoNiReP alloy films with large Re content (up to 27 at%), obtained in a citrate-glycine based electrolyte have been studied as a function of the electrodeposition technique. Direct current (DC), pulse plating (PP) and reverse pulse plating (RPP) were considered with cathodic current densities from −50 mA cm−2 to −250 mA cm−2. The mechanical and magnetic properties have been analyzed and the data obtained has been correlated with composition and crystallographic structure. For values of j (DC), jon (PP) and jc (RPP) below −100 mA cm−2, Co-rich, P-containing deposits are obtained. Beyond these current densities, both the quantities of Ni and Re increase simultaneously at the expense of Co and P, the latter virtually falling to zero. The highest Re percentage (25-27 at%) was achieved in both PP and RPP conditions at a cathodic pulse of −250 mA cm−2. All the films were either entirely nanocrystalline in nature or partially amorphous. Hardness values as high as 9.2 GPa have been found in PP plated Co64Ni18Re18 deposits. Besides the large hardness, the incorporation of Re in the films leads to high elastic recovery values. The magnetic character of the deposits ranges from soft to semi-hard ferromagneti

    Grain boundary segregation and interdiffusion effects in nickel-copper alloys : an effective means to improve the thermal stability of nanocrystalline nickel

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    Nanocrystalline (nc) Ni films show pronounced grain growth and suffer from concomitant deterioration of their mechanical and magnetic properties after annealing at relatively low temperatures (T(ANN) ≥ 475 K). This constitutes a drawback for their applicability as coatings or in components of miniaturized devices. This work reveals that the thermal stability of nc Ni is significantly improved by controllably alloying Ni with Cu, by means of electrodeposition, to form a Ni(1-x)Cu(x) solid solution. To tune the composition of such nc alloys, Ni(1-x)Cu(x) films are deposited galvanostatically using an electrolytic bath containing Ni and Cu sulfate salts as electroactive species, saccharine as grain-refining agent, and applying current densities ranging from -10 to -40 mA cm(-2). The enhanced thermal stability is ascribed to segregation of a Cu-rich phase at the Ni(1-x)Cu(x) grain boundaries, which acts as a shielding layer against grain growth. As a result, high values of hardness (in excess of 6 GPa) remain in nc Ni(1-x)Cu(x) for x ≥ 0.3, even after annealing at T(ANN) ≥ 575 K. From a magnetic point of view, Ni(1-x)Cu(x) films possess lower coercivity values than pure nc Ni films, both in the as-prepared and annealed states, thus offering potential advantages for certain soft magnetic applications

    Association between diet-quality scores, adiposity, total cholesterol and markers of nutritional status in European adults: findings from the Food4Me study

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    Diet-quality scores (DQS), which are developed across the globe, are used to define adherence to specific eating patterns and have been associated with risk of coronary heart disease and type-II diabetes. We explored the association between five diet-quality scores (Healthy Eating Index, HEI; Alternate Healthy Eating Index, AHEI; MedDietScore, MDS; PREDIMED Mediterranean Diet Score, P-MDS; Dutch Healthy Diet-Index, DHDI) and markers of metabolic health (anthropometry, objective physical activity levels (PAL), and dried blood spot total cholesterol (TC), total carotenoids, and omega-3 index) in the Food4Me cohort, using regression analysis. Dietary intake was assessed using a validated Food Frequency Questionnaire. Participants (n = 1480) were adults recruited from seven European Union (EU) countries. Overall, women had higher HEI and AHEI than men (p < 0.05), and scores varied significantly between countries. For all DQS, higher scores were associated with lower body mass index, lower waist-to-height ratio and waist circumference, and higher total carotenoids and omega-3-index (p trends < 0.05). Higher HEI, AHEI, DHDI, and P-MDS scores were associated with increased daily PAL, moderate and vigorous activity, and reduced sedentary behaviour (p trend < 0.05). We observed no association between DQS and TC. To conclude, higher DQS, which reflect better dietary patterns, were associated with markers of better nutritional status and metabolic health

    I will not go, I cannot go: cultural and social limitations of disaster preparedness in Asia, Africa, and Oceania

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    While much work has been invested in addressing the economic and technical basis of disaster preparedness, less effort has been directed towards understanding the cultural and social obstacles to and opportunities for disaster risk reduction. This paper presents local insights from five different national settings into the cultural and social contexts of disaster preparedness. In most cases, an early warning system was in place, but it failed to alert people to diverse environmental shocks. The research findings show that despite geographical and typological differences in these locations, the limitations of the systems were fairly similar. In Kenya, people received warnings, but from contradictory systems, whereas in the Philippines and on the island of Saipan, people did not understand the messages or take them seriously. In Bangladesh and Nepal, however, a deeper cultural and religious reasoning serves to explain disasters, and how to prevent them or find safety when they strike

    Fungal diversity notes 253–366: taxonomic and phylogenetic contributions to fungal taxa

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    Notes on 113 fungal taxa are compiled in this paper, including 11 new genera, 89 new species, one new subspecies, three new combinations and seven reference specimens. A wide geographic and taxonomic range of fungal taxa are detailed. In the Ascomycota the new genera Angustospora (Testudinaceae), Camporesia (Xylariaceae), Clematidis, Crassiparies (Pleosporales genera incertae sedis), Farasanispora, Longiostiolum (Pleosporales genera incertae sedis), Multilocularia (Parabambusicolaceae), Neophaeocryptopus (Dothideaceae), Parameliola (Pleosporales genera incertae sedis), and Towyspora (Lentitheciaceae) are introduced. Newly introduced species are Angustospora nilensis, Aniptodera aquibella, Annulohypoxylon albidiscum, Astrocystis thailandica, Camporesia sambuci, Clematidis italica, Colletotrichum menispermi, C. quinquefoliae, Comoclathris pimpinellae, Crassiparies quadrisporus, Cytospora salicicola, Diatrype thailandica, Dothiorella rhamni, Durotheca macrostroma, Farasanispora avicenniae, Halorosellinia rhizophorae, Humicola koreana, Hypoxylon lilloi, Kirschsteiniothelia tectonae, Lindgomyces okinawaensis, Longiostiolum tectonae, Lophiostoma pseudoarmatisporum, Moelleriella phukhiaoensis, M. pongdueatensis, Mucoharknessia anthoxanthi, Multilocularia bambusae, Multiseptospora thysanolaenae, Neophaeocryptopus cytisi, Ocellularia arachchigei, O. ratnapurensis, Ochronectria thailandica, Ophiocordyceps karstii, Parameliola acaciae, P. dimocarpi, Parastagonospora cumpignensis, Pseudodidymosphaeria phlei, Polyplosphaeria thailandica, Pseudolachnella brevifusiformis, Psiloglonium macrosporum, Rhabdodiscus albodenticulatus, Rosellinia chiangmaiensis, Saccothecium rubi, Seimatosporium pseudocornii, S. pseudorosae, Sigarispora ononidis and Towyspora aestuari. New combinations are provided for Eutiarosporella dactylidis (sexual morph described and illustrated) and Pseudocamarosporium pini. Descriptions, illustrations and / or reference specimens are designated for Aposphaeria corallinolutea, Cryptovalsa ampelina, Dothiorella vidmadera, Ophiocordyceps formosana, Petrakia echinata, Phragmoporthe conformis and Pseudocamarosporium pini. The new species of Basidiomycota are Agaricus coccyginus, A. luteofibrillosus, Amanita atrobrunnea, A. digitosa, A. gleocystidiosa, A. pyriformis, A. strobilipes, Bondarzewia tibetica, Cortinarius albosericeus, C. badioflavidus, C. dentigratus, C. duboisensis, C. fragrantissimus, C. roseobasilis, C. vinaceobrunneus, C. vinaceogrisescens, C. wahkiacus, Cyanoboletus hymenoglutinosus, Fomitiporia atlantica, F. subtilissima, Ganoderma wuzhishanensis, Inonotus shoreicola, Lactifluus armeniacus, L. ramipilosus, Leccinum indoaurantiacum, Musumecia alpina, M. sardoa, Russula amethystina subp. tengii and R. wangii are introduced. Descriptions, illustrations, notes and / or reference specimens are designated for Clarkeinda trachodes, Dentocorticium ussuricum, Galzinia longibasidia, Lentinus stuppeus and Leptocorticium tenellum. The other new genera, species new combinations are Anaeromyces robustus, Neocallimastix californiae and Piromyces finnis from Neocallimastigomycota, Phytophthora estuarina, P. rhizophorae, Salispina, S. intermedia, S. lobata and S. spinosa from Oomycota, and Absidia stercoraria, Gongronella orasabula, Mortierella calciphila, Mucor caatinguensis, M. koreanus, M. merdicola and Rhizopus koreanus in Zygomycota

    Age at symptom onset and death and disease duration in genetic frontotemporal dementia : an international retrospective cohort study

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    Background: Frontotemporal dementia is a heterogenous neurodegenerative disorder, with about a third of cases being genetic. Most of this genetic component is accounted for by mutations in GRN, MAPT, and C9orf72. In this study, we aimed to complement previous phenotypic studies by doing an international study of age at symptom onset, age at death, and disease duration in individuals with mutations in GRN, MAPT, and C9orf72. Methods: In this international, retrospective cohort study, we collected data on age at symptom onset, age at death, and disease duration for patients with pathogenic mutations in the GRN and MAPT genes and pathological expansions in the C9orf72 gene through the Frontotemporal Dementia Prevention Initiative and from published papers. We used mixed effects models to explore differences in age at onset, age at death, and disease duration between genetic groups and individual mutations. We also assessed correlations between the age at onset and at death of each individual and the age at onset and at death of their parents and the mean age at onset and at death of their family members. Lastly, we used mixed effects models to investigate the extent to which variability in age at onset and at death could be accounted for by family membership and the specific mutation carried. Findings: Data were available from 3403 individuals from 1492 families: 1433 with C9orf72 expansions (755 families), 1179 with GRN mutations (483 families, 130 different mutations), and 791 with MAPT mutations (254 families, 67 different mutations). Mean age at symptom onset and at death was 49\ub75 years (SD 10\ub70; onset) and 58\ub75 years (11\ub73; death) in the MAPT group, 58\ub72 years (9\ub78; onset) and 65\ub73 years (10\ub79; death) in the C9orf72 group, and 61\ub73 years (8\ub78; onset) and 68\ub78 years (9\ub77; death) in the GRN group. Mean disease duration was 6\ub74 years (SD 4\ub79) in the C9orf72 group, 7\ub71 years (3\ub79) in the GRN group, and 9\ub73 years (6\ub74) in the MAPT group. Individual age at onset and at death was significantly correlated with both parental age at onset and at death and with mean family age at onset and at death in all three groups, with a stronger correlation observed in the MAPT group (r=0\ub745 between individual and parental age at onset, r=0\ub763 between individual and mean family age at onset, r=0\ub758 between individual and parental age at death, and r=0\ub769 between individual and mean family age at death) than in either the C9orf72 group (r=0\ub732 individual and parental age at onset, r=0\ub736 individual and mean family age at onset, r=0\ub738 individual and parental age at death, and r=0\ub740 individual and mean family age at death) or the GRN group (r=0\ub722 individual and parental age at onset, r=0\ub718 individual and mean family age at onset, r=0\ub722 individual and parental age at death, and r=0\ub732 individual and mean family age at death). Modelling showed that the variability in age at onset and at death in the MAPT group was explained partly by the specific mutation (48%, 95% CI 35\u201362, for age at onset; 61%, 47\u201373, for age at death), and even more by family membership (66%, 56\u201375, for age at onset; 74%, 65\u201382, for age at death). In the GRN group, only 2% (0\u201310) of the variability of age at onset and 9% (3\u201321) of that of age of death was explained by the specific mutation, whereas 14% (9\u201322) of the variability of age at onset and 20% (12\u201330) of that of age at death was explained by family membership. In the C9orf72 group, family membership explained 17% (11\u201326) of the variability of age at onset and 19% (12\u201329) of that of age at death. Interpretation: Our study showed that age at symptom onset and at death of people with genetic frontotemporal dementia is influenced by genetic group and, particularly for MAPT mutations, by the specific mutation carried and by family membership. Although estimation of age at onset will be an important factor in future pre-symptomatic therapeutic trials for all three genetic groups, our study suggests that data from other members of the family will be particularly helpful only for individuals with MAPT mutations. Further work in identifying both genetic and environmental factors that modify phenotype in all groups will be important to improve such estimates. Funding: UK Medical Research Council, National Institute for Health Research, and Alzheimer's Society
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