This paper attempts to allocate a segment of the Paleozoic Ocean situated in what is now Southeastern Europe (SEE) into a regional geological and paleotectonic synthesis connecting the sedimentary, metamorphic and igneous records associated with the ocean’s cycle. The Supragetic basement (external section of the Carpatho-Balkan arch) represents a tectonically reworked basement vestige of the Neoproterozoic–Lower Paleozoic oceanic floor system recrystallized under regional low temperature greenschist-facies conditions. The regional geological constraints associated with this low-grade basement are integrated with information from the overlying Silurian, Devonian and Lower Carboniferous cap-rocks of the “Kučaj Unit” to demonstrate the presence of a major Paleozoic ocean crossing this segment of SEE. In connection with the Lower Paleozoic north Gondwanan Pan- African processes, the low-grade Supragetic basement (including its Devonian cover) is in a complex relationship with the occasionally anchimetamorphic Silurian, Devonian, and Lower Carboniferous deep-water record of the polymetamorphic “Kučaj Unit”. The Upper Devonian–Lower Carboniferous flysch and molasse of the “Kučaj Unit” are interposed with the Neoproterozic–Lower Paleozoic oceanic vestige or with the Supragetic basement with the corresponding Devonian Balkan-Carpathian back-arc ophiolite-bearing lithosphere and its carrier (Danubian Unit). This regional-scale synthesis demonstrates that a segment of the Rheic Ocean referred to as the Saxo-Thuringian seaway and its suture lay to the east, underneath the Permian red-bed overstepping sequence and to the west of the Danubian aggregation. Unlike many of the high-pressure rocks characterizing the segment of the Rheic suture in the Central European Variscides, the SEE zone described here has only a mild overprint.
Titanium alloy (Ti-6Al-4V) has been extensively used in aircraft turbine-engine components, aircraft structural components, aerospace fasteners, high performance automotive parts, marine applications, medical devices and sports equipment. However, wide-spread use of this alloy has limits because of difficulty to machine it. One of the major difficulties found during machining is development of poor quality of surface in the form of higher surface roughness. The present investigation has been concentrated on studying the effects of cutting parameters of cutting speed, feed rate and depth of cut on surface roughness of the product during turning of titanium alloy. Box-Behnken experimental design was used to collect data for surface roughness. ANOVA was used to determine the significance of the cutting parameters. The model equation is also formulated to predict surface roughness. Optimal values of cutting parameters were determined through response surface methodology. A 100% desirability level in the turning process for economy was indicated by the optimized model. Also, the predicted values that were obtained through regression equation were found to be in close agreement to the experimental values.