Investigating the amount of zeroing in modern sediments of River Danube, Austria

Sediments attributed to flooding events of River Danube concerning the bleaching of the optical stimulated luminescence (OSL) signal were investigated. It is demonstrated that the OSL signal in both quartz and feldspar is not completely but differentially bleached in the sediment grains. Partial bleaching of the samples is clearly indicated by the scatter of equivalent dose determined for several individual single aliquots. It is also shown that residual ages in feldspars are significantly higher than those calculated for quartz. It is furthermore demonstrated that analysing measurement-time dependent equivalent dose estimates is not a suitable method to identify partial bleaching in the investigated sediment grains. However, the transport and deposition process of the investigated samples was probably disturbed by an artificial input of sediment, and this case study may thus not be representative of undisturbed high flood events in the past.     

Amorphous copper and zinc sulfides in the metalliferous sediments of the Red Sea

Detailed studies on the copper and zinc distribution in metalliferous sediments from the Atlantis II Deep (Red Sea) demonstrate that beside chalcopyrite and sphalerite appreciable amounts of copper and zinc are found in X-ray amorphous copper and zinc sulfides not previously described. Only low contents of copper and zinc are present in nontronites, hydroxides and carbonates.     

Morphologische und Tektonische Initialursachen Grosser Klimaschwankungen

Ohne Zusammenfassung     

Energy and tectonics of Fennoscandian earthquakes

Energy-time release curves are calculated for Swedish and for Fennoscandian earthquakes, both curves exhibiting a sharp break around the year 1910. The similarity of this behaviour with world-wide energy release curves suggests that Fennoscandian earthquakes are related to the global tectonics, probably via plate motions on the border between the North Atlantic and the Eurasian continent.     

A note on the relation of size to ecological value of some wetlands

Marshes located on the Mayo Peninsula between the South and Rhode rivers, Maryland, were measured to determine acreage per tract, total upland and seaward edge lengths. For these marshes, 54% of the total area is associated with tracts of less than 5 acres. Of total upland edge length, 68% is along tracts less than 5 acres, while 72% of seaward edge length is associated with these smaller tracts. Comparison of edge length to area ratios shows that tracts of 1 acre or less have significantly higher edge length than tracts of 5 acres or more. While this should be extrapolated to other geographic regions with care, the findings suggest that regulatory agencies revise wetland management principles to include greater protection and enhanced survival of small tracts.     

Tectono‐sedimentary evolution of lower to middle Miocene half‐graben basins related to an extensional detachment fault (western Crete,Greece)

Crustal extension in the overriding plate at the Aegean subduction zone, related to the rollback of the subducting African slab in the Miocene, resulted in a detachment fault separating high‐pressure/low‐temperature (HP‐LT) metamorphic lower from non‐metamorphic upper tectonic units on Crete. In western Crete, detachment faulting at deeper crustal levels was accompanied by structural disintegration of the hangingwall leading to the formation of half‐graben‐type sedimentary basins filled by alluvial fan and fan‐delta deposits. The coarse‐grained clastic sediments in these half‐grabens are exclusively derived from the non‐metamorphic units atop the detachment fault. Being in direct tectonic contact with HP‐LT metamorphic rocks of the lower tectonic units today, the basins must have formed in the period between c. 20 and 15 Ma, prior to the exposure of the HP‐LT metamorphic rocks at the surface, and juxtaposed with the latter during ongoing deformation.     

Numerical and Experimental Analysis of A Ducted Propeller Designed by A Fully Automated Optimization Process Under Open Water Condition

A fully automated optimization process is provided for the design of ducted propellers under open water conditions, including 3D geometry modeling, meshing, optimization algorithm and CFD analysis techniques. The developed process allows the direct integration of a RANSE solver in the design stage. A practical ducted propeller design case study is carried out for validation. Numerical simulations and open water tests are fulfilled and proved that the optimum ducted propeller improves hydrodynamic performance as predicted.