Extraordinary Performance of Carbon-Coated Anatase TiO2 as Sodium-Ion Anode

The synthesis of in situ polymer-functionalized anatase TiO2 particles using an anchoring block copolymer with hydroxamate as coordinating species is reported, which yields nanoparticles (≈11 nm) in multigram scale. Thermal annealing converts the polymer brushes into a uniform and homogeneous carbon coating as proven by high resolution transmission electron microscopy and Raman spectroscopy. The strong impact of particle size as well as carbon coating on the electrochemical performance of anatase TiO2 is demonstrated. Downsizing the particles leads to higher reversible uptake/release of sodium cations per formula unit TiO2 (e.g., 0.72 eq. Na+ (11 nm) vs only 0.56 eq. Na+ (40 nm)) while the carbon coating improves rate performance. The combination of small particle size and homogeneous carbon coating allows for the excellent electrochemical performance of anatase TiO2 at high (134 mAh g−1 at 10 C (3.35 A g−1)) and low (≈227 mAh g−1 at 0.1 C) current rates, high cycling stability (full capacity retention between 2nd and 300th cycle at 1 C) and improved coulombic efficiency (≈99.8%)

The Impact of Global Warming and Anoxia on Marine Benthic Community Dynamics: an Example from the Toarcian (Early Jurassic)

The Pliensbachian-Toarcian (Early Jurassic) fossil record is an archive of natural data of benthic community response to global warming and marine long-term hypoxia and anoxia. In the early Toarcian mean temperatures increased by the same order of magnitude as that predicted for the near future; laminated, organic-rich, black shales were deposited in many shallow water epicontinental basins; and a biotic crisis occurred in the marine realm, with the extinction of approximately 5% of families and 26% of genera. High-resolution quantitative abundance data of benthic invertebrates were collected from the Cleveland Basin (North Yorkshire, UK), and analysed with multivariate statistical methods to detect how the fauna responded to environmental changes during the early Toarcian. Twelve biofacies were identified. Their changes through time closely resemble the pattern of faunal degradation and recovery observed in modern habitats affected by anoxia. All four successional stages of community structure recorded in modern studies are recognised in the fossil data (i.e. Stage III: climax; II: transitional; I: pioneer; 0: highly disturbed). Two main faunal turnover events occurred: (i) at the onset of anoxia, with the extinction of most benthic species and the survival of a few adapted to thrive in low-oxygen conditions (Stages I to 0) and (ii) in the recovery, when newly evolved species colonized the re-oxygenated soft sediments and the path of recovery did not retrace of pattern of ecological degradation (Stages I to II). The ordination of samples coupled with sedimentological and palaeotemperature proxy data indicate that the onset of anoxia and the extinction horizon coincide with both a rise in temperature and sea level. Our study of how faunal associations co-vary with long and short term sea level and temperature changes has implications for predicting the long-term effects of “dead zones” in modern oceans

Kinetic inductance detectors (KIDs) for the SAFARI instrument on SPICA

Kinetic Inductance Detectors (KIDs) with frequency domain read-out are intrinsically very suitable to use as building blocks for very large arrays. KIDs therefore are an attractive detector option for the SAFARI instrument on SPICA, Millimetron and also for large scale ground based imaging arrays. To study the properties of large KID arrays we have fabricated 400 pixels array made from 40 nm thick Al films on high resistivity Si substrates. The array is tested in a dry dilution refrigerator at 100 mK. We present the device design and experimental results. We also present a new design of the array with lithographic air bridges over the coplanar waveguide feedline. The air bridges are designed to suppress the slot line mode in the feedline and that will improve the pixel to pixel reproducibility of large arrays

Permian-Triassic boundary microbialites (PTBMs) in soutwest China: implications for paleoenvironment reconstruction

Permian–Triassic boundary microbialites (PTBMs) are commonly interpreted to be a sedimentary response to upwelling of anoxic alkaline seawater and indicate a harsh marine environment in the Permian–Triassic transition. However, recent studies propose that PTBMs may instead be developed in an oxic environment, therefore necessitating the need to reassess the paleoenvironment of formation of PTBMs. This paper is an integrated study of the PTBM sequence at Yudongzi, northwest Sichuan Basin, which is one of the thickest units of PTBMs in south China. Analysis of conodont biostratigraphy, mega- to microscopic microbialite structures, stratigraphic variations in abundance and size of metazoan fossils, and total organic carbon (TOC) and total sulfur (TS) contents within the PTBM reveals the following results: (1) the microbialites occur mainly in the Hindeodus parvus Zone but may cross the Permian–Triassic boundary, and are comprised of, from bottom to top: lamellar thrombolites, dendritic thrombolites and lamellar-reticular thrombolites; (2) most metazoan fossils of the microbialite succession increase in abundance upsection, so does the sizes of bivalve and brachiopod fossils; (3) TOC and TS values of microbialites account respectively for 0.07 and 0.31 wt% on average, both of which are very low. The combination of increase in abundance and size of metazoan fossils upsection, together with the low TOC and TS contents, is evidence that the Yudongzi PTBMs developed in oxic seawater. We thus dispute the previous view, at least for the Chinese sequences, of low-oxygen seawater for microbialite growth, and question whether it is now appropriate to associate PTBMs with anoxic, harsh environments associated with the end-Permian extinction. Instead, we interpret those conditions as fully oxygenated.13th Five-Year Plan National Scientific and Technology Major Project (2016ZX05004002-001); National Natural Science Foundation of China (41602166)

Verbesserung chemischer und physikalischer Methoden zur Aufbereitung radioaktiver Abwässer aus Kernkraftwerken

In the Federal Republic of Germany the treatment of radioactive waste water from nuclear power plants is almost exclusively done by means of evaporation. Only the washing and shower bath water with little radioactivity are purified by means of alluvial filters. In this study, the author presents a flocculation precipitation process for radioactive waste water from PWRs. It eliminates especially antimony 124. This process makes it possible to obtain the legally prescribed waste water minimum values of 5 $\cdot$ 10$^{-4}$ Ci/m$^{3}$ of total $\alpha$-activity. As for the purification of the radioactive waste water by means of evaporators, special emphases is placed on the separation of aerosols from the steam phase. Up to now columns with perforated bottoms or bubble trays have been used for this purpose. In this study, the author describes a considerably more effective method for he decontamination of the steam phase, the separation of the aerosols being done by means of an electrostatic filter. First test results with a model evaporator are described

The enigmatic ichnofossil Tisoa siphonalis and widespread authigenic seep carbonate formation during the Late Pliensbachian in southern France

Tubular carbonate concretions of up to 1 m in length and perpendicular to bedding, occur abundantly in the Upper Pliensbachian (upper Amaltheus margaritatus Zone, Gibbosus Subzone) in outcrops (Fontaneilles section) in the vicinity of Rivière-sûr-Tarn, southern France. Stable isotope analyses of these concretions show negative δ13C values that decrease from the rim to the center from −18.8‰ to −25.7‰ (V-PDB), but normal marine δ18O values (−1.8‰). Carbon isotope analyses of Late Pliensbachian bulk carbonate (matrix) samples from the Fontaneilles section show clearly decreasing C-isotope values across the A. margaritatus Zone, from +1‰ to −3‰ (V-PDB). Isotope analyses of coeval belemnite rostra do not document such a negative C-isotope trend with values remaining stable around +2‰ (V-PDB). Computer tomographic (CT) scanning of the tubular concretions show multiple canals that are lined or filled entirely with pyrite. Previously, the formation of these concretions with one, two, or more central tubes, has been ascribed to the activity of an enigmatic organism, possibly with annelid or arthropod affinities, known asTisoa siphonalis. Our results suggest tisoan structures are abiogenic. Based on our geochemical analyses and sedimentological observations we suggest that these concretions formed as a combination of the anaerobic oxidation of methane (AOM) and sulfate reduction within the sediment. Fluids rich in methane and/or hydrocarbons likely altered local bulk rock carbon isotope records, but did not affect the global carbon cycle. Interestingly, Tisoa siphonalis has been described from many locations in the Grands Causses Basin in southern France, and from northern France and Luxemburg, always occurring at the same stratigraphic level. Upper Pliensbachian authigenic carbonates thus possibly cover an area of many thousand square kilometers. Greatly reduced sedimentation rates are needed to explain the stabilization of the sulfate-methane transition zone in the sedimentary column in order for the tubular concretions to form. Late Pliensbachian cooling, reducing run-off, and/or the influx of colder water and more vigorous circulation could be responsible for a halt in sedimentation. At the same time (thermogenic) methane may have destabilized during a major phase of Late Pliensbachian sea level fall. As such Tisoa siphonalis is more than a geological curiosity, and its further study could prove pivotal in understanding Early Jurassic paleoenvironmental change