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[1] Recent findings for a young (31.5 [+ or -] 0.7 Ma) age of high-pressure metamorphism at ~90 km depths in the Eclogite Zone of the Tauern Window, Eastern Alps, prompt the question about the timing of the structural development of the Tauern Window and its relation to high-pressure metamorphism. We show that all major structures in the Tauern Window, resulting from strong N-S lithospheric shortening and simultaneous minor E-W extension, began developing coevally with high-pressure metamorphism in the Eclogite Zone. Large-scale strike-slip shear zones started to form at ~32-30 Ma and facilitated the spatial accommodation of simultaneous shortening and extension. At least some of the strike-slip and extensional shear zones operated into the Middle Miocene, either continuously or intermittently, with pronounced activity at ~21-15 Ma. The considerable exhumation of the Eclogite Zone from ~90 km depths into the middle crust, and the tectonic development of its framework occurred within only 1-2 Ma after eclogitization. This is evidenced by almost identical ages for eclogite facies metamorphism and for the development of the major structures that bound the Eclogite Zone under blueschist- and greenschist facies metamorphic conditions. We discuss a tectonic model in which considerable transpressional shortening and thickening took place in the present central-southern part of the Tauern Window. We propose that the Tauern Window nucleated here and that most of the regional deformation at ~32-30 Ma is today found at the periphery of the window and in the adjacent Austroalpine units. Afterward, transpression continued, the window grew to the E, W, and N, and deformation progressed to those parts of the window. Ductile deformation in the present-day surface level ceased at ~15 Ma.

Byline: Johannes Glodny (1), Alexander Kuhn (2,3), Hakon Austrheim (3) Keywords: Eclogite; Amphibolite; Fluid--rock interaction; Rb--Sr; U--Pb; Norway Abstract: Rb--Sr multimineral isochron data for metamorphic veins allow to date separate increments of the mineral reaction history of polymetamorphic terranes. Granulite facies rocks of the Lindas nappe, Bergen Arcs, Norway, were subducted and exhumed during the Caledonian orogeny. The rocks show petrographic evidence for two distinct events of local fluid infiltration and vein formation, along fractures and shear zones. The first occurred at eclogite facies (15--21 kbar, 650--750degC) and a later one at amphibolite facies conditions (8--10 kbar, 600degC). The presence of fluids enabled local metamorphic equilibration only near fluid pathways. In fluid-absent domains, preexisting assemblages were metastably preserved. This resulted in a heterogeneity of metamorphic signatures on meter to um-scales. Well-preserved granulite facies rocks preserve their Proterozoic Rb--Sr mineral ages, as does the U--Pb system of zircon in most lithologies. Six Rb/Sr multimineral isochron ages for eclogite facies veins and their immediate wallrocks date the fluid-induced eclogitization at 429.9 +- 3.5 Ma (2[sigma], weighted average, MSWD = 0.39). An eclogite facies vein has yielded metamorphic zircon with concordant U--Pb ages of 429 +- 3 Ma, identical to the U--Pb age of 427.4 +- 0.9 Ma for zircon xenocrysts in an amphibolite facies vein. Seven Rb/Sr mineral isochron ages date amphibolite-facies fluid infiltration at 414.2 +- 2.8 Ma (MSWD = 1.5), an age value testifying to residence of the rocks in the deep orogenic crust at temperatures >600degC for nearly 15 Ma. The new data show that Rb--Sr mineral isochron ages effectively date fluid-induced (re)crystallization events rather than stages of cooling. The direct link between isotopic ages and distinct petrographic equilibrium assemblages aids to constrain the evolution of rocks in the P--T-reaction-time space, which is essential for understanding exhumation histories and the internal dynamics of orogens in general. Author Affiliation: (1) GeoForschungsZentrum Potsdam, Telegrafenberg C2, 14473, Potsdam, Germany (2) Institut fur Geowissenschaften, Johannes Gutenberg-Universitat, Becherweg 21, 55099, Mainz, Germany (3) PGP and Department of Earth Sciences, University of Oslo, Postboks 1047, 0316, Oslo, Norway Article History: Registration Date: 27/11/2007 Received Date: 23/04/2007 Accepted Date: 27/11/2007 Online Date: 14/12/2007 Article note: Communicated by Jochen Hoefs. Electronic supplementary material The online version of this article (doi: 10.1007/s00410-007-0272-y) contains supplementary material, which is available to authorized users.

Structural and metamorphic data from the island of Amorgos (central Aegean Sea) show evidence for the existence of two distinct high-pressure units, the Metabasite Unit and the Basal Conglomerate Unit. These are exposed at the base of a thick marble sequence and overlying flysch deposits. The Metabasite Unit is characterized by a mineral assemblage of blue amphibole, garnet and clinopyroxene, indicating P-T conditions of 500-600 [degrees]C and >13 kbar. It is juxtaposed below carpholite-bearing metaconglomerates and quartz-rich micaschists of the Basal Conglomerate Unit, for which metamorphic conditions of 300-450 [degrees]C and 10-14 kbar are estimated. The contact between the two units is interpreted as a low-angle detachment fault that accommodated top-to-the-NW sense of motion. The Amorgos succession above the Basal Conglomerate Unit collectively resembles the stratigraphy of external units in the Hellenides and could possibly be correlated with the so-called 'Basal Unit', which crops out in a number of tectonic windows throughout the Aegean Sea. This means that the Metabasite Unit in Amorgos could possibly represent the lowermost structural unit in the central Aegean Sea.

Recent work on the preparation of highly organized macroporous electrodes and nanoporous ultramicroelectrodes has been combined and extended to elaborate macroporous ultramicroelectrodes (UMEs) by template synthesis using colloidal crystals and following two different and complementary methods. On the one hand, arched porous UMEs were prepared, and on the other hand, cylindrical porous UMEs were obtained by using cavity UMEs. These macroporous UMEs have an active surface area which is up to 2 orders of magnitude higher compared to that of a classical disk UME as characterized by cyclic voltammetry. To study their analytical performance, the macroporous UMEs have been modified with a redox-active thiol and also a model bioelectrocatalytical system containing a redox mediator, a cofactor, and glucose-dehydrogenase. In both cases the electrochemical signal is amplified by up to 2 orders of magnitude, which increases significantly the analytical performance of such electrodes and therefore opens up new applications for this kind of miniaturized electrochemical system.

In this study, various experimental tests were carried out with a 1 MW th circulating fluidized bed pilot plant at the Technical University of Darmstadt to investigate the combustion and co-combustion behaviour of different fuels under load change conditions in air and oxyfuel mode. The combustion tests were carried out with low-calorific lignite and hard coal as reference cases for co-combustion. In the co-combustion experimental tests, straw pellets, and refuse-derived fuels (high and low calorific) were used as co-fuels for coal. In addition, a comprehensive dynamic 1.5-D process simulation model was established for a 1 MW th circulating fluidized bed pilot plant. The model created with the "APROS" software precisely reproduces both the gas/solids and the water/steam side of the 1 MW th pilot plant. The dynamic process simulation model was first validated at various steady-state operation points and, in a second step, at various dynamic load changes. The numerical results, such as the pressure drop and temperature profiles along the fluidized bed riser as well as the flue gas concentrations at the cyclone outlet, were compared with the measurements and showed agreement during the long-term tests of the combustion and co-combustion processes. • A series of combustion and co-combustion tests were carried out in a 1 MW th CFB pilot plant. • The tests were carried out using different fuels under load cycling in air and in oxyfuel modes. • In all tests, stable reactor operation was achieved under load cycling in air and in oxyfuel modes. • A 1.5-D dynamic process simulation model was developed and validated with experimental tests. • The numerical results are in good agreement with the measurements obtained from the pilot plant. [ABSTRACT FROM AUTHOR]

Living systems that can spontaneously exhibit directional motion belong to diverse classes such as bacteria, sperm and plankton. They have fascinated scientists in recent years to design completely artificial or biohybrid mobile objects. Natural ingredients, like parts of plants, have been used to elaborate miniaturized dynamic objects, which can move when they are combined with other, non‐natural, building blocks. Herein, we report that the precise structural tailoring of natural plant leaves allows generating a spatially predefined and confined release of oxygen gas, due to the conversion of carbon dioxide. This constitutes the driving force for generating motion, which is solely due to the respiration of leaves by photosynthesis. The rate of gas evolution can be fine‐tuned by changing the light intensity and the leaf size, allowing ultimately to control the motility of objects with dimensions ranging from the millimeter to the micrometer scale. [ABSTRACT FROM AUTHOR]

A simple, inexpensive, conceptually uncomplicated student experiment involving adsorption of polyoxometalate on graphite electrodes has been developed for teaching surface electrochemistry. The experiment has been used for fourth-year students. Among things students will become familiar with are cyclic voltammetry, capacitive current, and spontaneous chemisorption. Much research is being done in the area of modified electrodes and students should be introduced to it.

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Electrochemical regeneration of reduced nicotinamide adenine dinucleotide (NADH) is an extremely important challenge for the electroenzymatic synthesis of many valuable chemicals. Although some important progress has been made with modified electrodes concerning the reduction of NAD+, the scale‐up is difficult due to mass transport limitations inherent to large‐size electrodes. Here, we propose instead to employ a dispersion of electrocatalytically active modified microparticles in the bulk of a bipolar electrochemical cell. In this way, redox reactions occur simultaneously on all of these individual microelectrodes without the need of a direct electrical connection. The concept is validated by using [Rh(Cp*)(bpy)Cl]+ functionalized surfaces, either of carbon felt as a reference material, or carbon microbeads acting as bipolar objects. In the latter case, enzymatically active 1,4‐NADH is electroregenerated at the negatively polarized face of the particles. The efficiency of the system can be fine‐tuned by controlling the electric field in the reaction compartment and the number of dispersed microelectrodes. This wireless bioelectrocatalytic approach opens up very interesting perspectives for electroenzymatic synthesis in the bulk phase. [ABSTRACT FROM AUTHOR]

Conducting polymers have been extensively studied due to their potential applications ranging from sensing to energy storage, and environmental remediation. They can be easily generated by electrosynthesis and have also very interesting electrochemical features, which have been mostly examined with classic electrochemical approaches. Bipolar electrochemistry offers an attractive alternative way to synthesize and characterize the physico‐chemical properties of conducting polymers. The wireless and asymmetric features of bipolar electrochemistry can be advantageously combined with the electroactivity, tunability and easy processability of conducting polymers. This synergy has been increasingly explored in recent years for the controlled electrogeneration, surface modification and characterization of different π‐conjugated polymers. This review summarizes the advances in this context and also discusses some unconventional applications such as wireless light‐emitting devices and actuators. [ABSTRACT FROM AUTHOR]

Ionic mobilities can be determined in the chemistry laboratory using thin-layer electrodeposition of metals with interfacial perturbation-sensitive morphologies. A well-defined morphological transition is generated by alkali cations on the deposit, allowing the determination to be performed. Experiment procedures using a simple electrochemical cell are included.