High-Throughput Measurement of Ionic Conductivity in Composition-Spread Thin Films

This paper demonstrates the feasibility of high-throughput investigation of ionic conductivity in oxygen-ion conductors. Yttria stabilized zirconia (YSZ) composition-spread thin films with nanometer-size grains were prepared by 90° off-axis reactive RF cosputtering. We compare results for two electrode configurations, namely, out-of-plane (parallel plate) and in-plane (planar interdigitated electrode) and find that the contribution from the intragrain conductivity in YSZ thin films (150 nm) is more explicit in the latter configuration because it greatly diminishes electrode effects. The intragrain oxygen ion conductivity of thin film YSZ was systematically measured as a function of yttria concentration over the range 2 mol % to 12 mol %. The results show that the measured conductivity of the YSZ thin films is close to that of corresponding bulk materials with a peak value around 3 × 10⁻⁴ S cm⁻¹ at 440 °C at the optimum Y₂O₃ concentration of 8 mol %. Validation of this technique means that it can be applied to novel chemical systems for which systematic bulk measurements have not been attempted

High-Throughput Measurement of Ionic Conductivity in Composition-Spread Thin Films

This paper demonstrates the feasibility of high-throughput investigation of ionic conductivity in oxygen-ion conductors. Yttria stabilized zirconia (YSZ) composition-spread thin films with nanometer-size grains were prepared by 90° off-axis reactive RF cosputtering. We compare results for two electrode configurations, namely, out-of-plane (parallel plate) and in-plane (planar interdigitated electrode) and find that the contribution from the intragrain conductivity in YSZ thin films (150 nm) is more explicit in the latter configuration because it greatly diminishes electrode effects. The intragrain oxygen ion conductivity of thin film YSZ was systematically measured as a function of yttria concentration over the range 2 mol % to 12 mol %. The results show that the measured conductivity of the YSZ thin films is close to that of corresponding bulk materials with a peak value around 3 × 10⁻⁴ S cm⁻¹ at 440 °C at the optimum Y₂O₃ concentration of 8 mol %. Validation of this technique means that it can be applied to novel chemical systems for which systematic bulk measurements have not been attempted

Hyperon-nucleon scattering and hyperon masses in the nuclear medium

We analyze low-energy hyperon-nucleon scattering using an effective field theory in next-to-leading order. By fitting experimental cross sections for laboratory hyperon momenta below 200 MeV/c and using information from the hypertriton we determine twelve contact-interaction coefficients. Based on these we discuss the low-density expansion of hyperon mass shifts in the nuclear medium.Comment: 10 pages, 2 figure

Research is needed to inform environmental management of hydrothermally inactive and extinct polymetallic sulfide (PMS) deposits

Polymetallic sulfide (PMS) deposits produced at hydrothermal vents in the deep sea are of potential interest to miners. Hydrothermally active sulfide ecosystems are valued for the extraordinary chemosynthetic communities that they support. Many countries, including Canada, Portugal, and the United States, protect vent ecosystems in their Exclusive Economic Zones. When hydrothermal activity ceases temporarily (dormancy) or permanently (extinction), the habitat and associated ecosystem change dramatically. Until recently, so-called "inactive sulfide" habitats, either dormant or extinct, received little attention from biologists. However, the need for environmental management of deep-sea mining places new imperatives for building scientific understanding of the structure and function of inactive PMS deposits. This paper calls for actions of the scientific community and the emergent seabed mining industry to i) undertake fundamental ecological descriptions and study of ecosystem functions and services associated with hydrothermally inactive PMS deposits, ii) evaluate potential environmental risks to ecosystems of inactive PMS deposits through research, and iii) identify environmental management needs that may enable mining of inactive PMS deposits. Mining of some extinct PMS deposits may have reduced environmental risk compared to other seabed mining activities, but this must be validated through scientific research on a case-by-case basis.FCT: IF/00029/2014/CP1230/CT0002/ UID/05634/2020/ CEECIND005262017/ UID/MAR/00350/2019; Direcao-Geral de Politica do Mar (DGPM) Mining2/2017/005/ Mining2/2017/001info:eu-repo/semantics/publishedVersio

Search for positively charged strangelets and other related results with E864 at the AGS

We report on the latest results in the search for positively charged strangelets from E864's 96/97 run at the AGS with sensitivity of about $8\times 10^{-9}$ per central collision. This contribution also contains new results of a search for highly charged strangelets with $Z=+3$. Production of light nuclei, such as $^6He$ and $^6Li$, is presented as well. Measurements of yields of these rarely produced isotopes near midrapidity will help constrain the production levels of strangelets via coalescence. E864 also measures antiproton production which includes decays from antihyperons. Comparisons with antiproton yields measured by E878 as a function of centrality indicate a large antihyperon-to-antiproton ratio in central collisions.Comment: 8 pages, 4 figures; Talk at SQM'98, Padova, Italy (July 20-24th, 1998

The spatial scale of genetic subdivision in populations of Ifremeria nautilei, a hydrothermal-vent gastropod from the southwest Pacific

<p>Abstract</p> <p>Background</p> <p>Deep-sea hydrothermal vents provide patchy, ephemeral habitats for specialized communities of animals that depend on chemoautotrophic primary production. Unlike eastern Pacific hydrothermal vents, where population structure has been studied at large (thousands of kilometres) and small (hundreds of meters) spatial scales, population structure of western Pacific vents has received limited attention. This study addresses the scale at which genetic differentiation occurs among populations of a western Pacific vent-restricted gastropod, <it>Ifremeria nautilei</it>.</p> <p>Results</p> <p>We used mitochondrial and DNA microsatellite markers to infer patterns of gene flow and population subdivision. A nested sampling strategy was employed to compare genetic diversity in discrete patches of <it>Ifremeria nautilei </it>separated by a few meters within a single vent field to distances as great as several thousand kilometres between back-arc basins that encompass the known range of the species. No genetic subdivisions were detected among patches, mounds, or sites within Manus Basin. Although <it>I. nautilei </it>from Lau and North Fiji Basins (~1000 km apart) also exhibited no evidence for genetic subdivision, these populations were genetically distinct from the Manus Basin population.</p> <p>Conclusions</p> <p>An unknown process that restricts contemporary gene flow isolates the Manus Basin population of <it>Ifremeria nautilei </it>from widespread populations that occupy the North Fiji and Lau Basins. A robust understanding of the genetic structure of hydrothermal vent populations at multiple spatial scales defines natural conservation units and can help minimize loss of genetic diversity in situations where human activities are proposed and managed.</p

Library Design in Combinatorial Chemistry by Monte Carlo Methods

Strategies for searching the space of variables in combinatorial chemistry experiments are presented, and a random energy model of combinatorial chemistry experiments is introduced. The search strategies, derived by analogy with the computer modeling technique of Monte Carlo, effectively search the variable space even in combinatorial chemistry experiments of modest size. Efficient implementations of the library design and redesign strategies are feasible with current experimental capabilities.Comment: 5 pages, 3 figure

Runaway Events Dominate the Heavy Tail of Citation Distributions

Statistical distributions with heavy tails are ubiquitous in natural and social phenomena. Since the entries in heavy tail have disproportional significance, the knowledge of its exact shape is very important. Citations of scientific papers form one of the best-known heavy tail distributions. Even in this case there is a considerable debate whether citation distribution follows the log-normal or power-law fit. The goal of our study is to solve this debate by measuring citation distribution for a very large and homogeneous data. We measured citation distribution for 418,438 Physics papers published in 1980-1989 and cited by 2008. While the log-normal fit deviates too strong from the data, the discrete power-law function with the exponent $\gamma=3.15$ does better and fits 99.955% of the data. However, the extreme tail of the distribution deviates upward even from the power-law fit and exhibits a dramatic "runaway" behavior. The onset of the runaway regime is revealed macroscopically as the paper garners 1000-1500 citations, however the microscopic measurements of autocorrelation in citation rates are able to predict this behavior in advance.Comment: 6 pages, 5 Figure