The authors show that the Mesoproterozoic (1.6-1.0 bn year before present) was no “boring billion” but a “bustling billion” - not only with Stromatolites and their apex in the Calymmian and Ectasian but also with the presence of multicellular organisms. To make it visible a graphical reconstruction was created. For a long time, it was assumed that there existed no noteworthy biosphere on Earth ...

Introduction Invasive alien species can have devastating consequences on native biodiversity, ecosystem and evolutionary processes (Lovett et al. 2006, McNeely 2001, Mooney and Cleland 2001). In the United States alone, economic costs associated with environmental damages and losses as a result of invasive species have been estimated to total between $120-137 billion per year (Pimentel et al. 2...

Chatter is a concern in boring process, due to the low dynamic stiffness of long cantilever boring bars. Chatter suppression in machining permits higher productivity and better surface finishes. The MR fluid, which changes stiffness and undergoes a phase transformation when subjected to an external magnetic field, is applied to adjust the stiffness of the boring bar and suppress chatter. The st...

Bioerosion by boring sponges is an important mechanism shaping the structure of coral reefs all around the world. To determine the excavation rate by boring sponges, we developed a system in which chemical and mechanical boring rates [calcium carbonate (CaCO(3)) dissolution and chip production, respectively] were measured simultaneously in experimental tanks containing reefal rock inhabited by ...

For rotating-tool machining, such as milling, line boring, and cylinder boring, the tool rotation causes the machining force on each tooth to rotate repetitively relative to the inertial coordinate frame. This is quite different than stationary-tool machining, such as turning or boring with a stationary boring bar, in which the force directions are fixed relative to the inertial frame. Although...