Entropy-based fault detection approach for motor vibration signals under accelerated aging process

The purpose of this study is to analyze motor vibration signals due to the bearing fault, which is artificially generated by aging process. Vibration signal data recorded by the experimental setup has been conditioned by a high-pass filter (Butterworth type) to reach the regarding frequency components of the bearing failure. Spectral analysis has been applied to realize the degradation on the bearing and the power spectral density figures revealed that the magnitudes of frequency components between 1.5-4 kHz bandwidth increased after every aging cycle. Vibration signals were investigated statistically by examining four main statistical parameters: mean value, standard deviation, skewness and kurtosis. Evaluation of these parameters indicated that significant variance occurred on standard deviation. At this point Shannon entropy became an approach to analyze the variance on the standard deviation. The probability of the aging cycles has been defined as a function of standard deviation values for each aging cycle. Entropy definition, which is a function of probability, determines the uncertainty level on the data and it has been examined to identify the effect of the aging progress on the bearing by examining the transferred entropy amount between aging cycles

The last reconnection of the Marmara Sea (Turkey) to the World Ocean : A paleoceanographic and paleoclimatic perspective

Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Marine Geology 255 (2008): 64-82, doi:10.1016/j.margeo.2008.07.005.During the late glacial, marine isotope Stage 2, the Marmara Sea transformed into a brackish lake as global sea level fell below the sill in the Dardanelles Strait. A record of the basin’s reconnection to the global ocean is preserved in its sediments permitting the extraction of the paleoceanographic and paleoclimatic history of the region. The goal of this study is to develop a high-resolution record of the lacustrine to marine transition of Marmara Sea in order to reconstruct regional and global climatic events at 24 a millennial scale. For this purpose, we mapped the paleoshorelines of Marmara Sea along the northern, eastern, and southern shelves at Çekmece, Prince Islands, and Imrali, using data from multibeam bathymetry, high-resolution subbottom profiling (chirp) and ten sediment cores. Detailed sedimentologic, biostratigraphic (foraminifers, mollusk, diatoms), X-ray fluorescence geochemical scanning, and oxygen and carbon stable isotope analyses correlated to a calibrated radiocarbon chronology provided evidence for cold and dry conditions prior to 15 ka BP, warm conditions of the Bolling-Allerod from ~15 to 13 ka BP, a rapid marine incursion at 12 ka BP, still stand of Marmara Sea and sediment reworking of the paleoshorelines during the Younger Dryas at ~11.5 to 10.5 ka BP, and development of strong stratification and influx of nutrients as Black Sea waters spilled into Marmara Sea at 9.2 ka BP. Stable environmental conditions developed in Marmara Sea after 6.0 ka BP as sea-level reached its present shoreline and the basin floors filled with sediments achieving their present configuration.Support for the analyses was from NSF-OCE-0222139; OCE-9807266 and PSC-CUNY 69138-00 38

The last sea level changes in the Black Sea: evidence from the seismic data

High resolution shallow seismic data collected from the southwestern shelf of the Black Sea indicate five different seismic stratigraphical units. The lower three of them belong to the Upper Cretaceous-Eocene, Oligocene-Miocene and Early Quaternary (prior to Holocene) sediments, respectively. These units are considered as a basement for the recent sediments deposited related to the latest connection of the Black Sea and the Mediterranean. The surface of these units are truncated to form an etchplain developed before the Flandrian transgression. The fourth unit covers the older units by an onlap. Its contact with the older units seen at -105 m is the shoreline of the Black Sea prior to the last major sea-level change. The fifth unit has been deposited since drowning of the Black Sea shelf. The principal cause of drowning of the Black Sea shelf is not only the last sea level rise as it is at the shelves of the Sea of Marmara but also the opening of the Strait of Istanbul. It is also realised by the comparison of the shelf area and the Catalca-Kocaeli etchplain that, the present continental part of this etchplain has been considerably uplifted with respect to the shelf area along the present shoreline. This uplifting must have also reactivated the faults around the Strait of Istanbul foundering the strait valley and, thus, permitting the Mediterranean waters to pass into the Black Sea, and initiating the sudden drowning of the Black Sea shelf. (C) 1999 Elsevier Science B.V. All rights reserved

Late Quaternary sedimentation and tectonics in the submarine Sarkoy Canyon, western Marmara Sea (Turkey)

Influences of tectonics and late Quaternary sea-level changes on sedimentation in the submarine Sarkoy Canyon, western Marmara Sea (Turkey) were investigated using a total of 37 seismic reflection profiles and 12 gravity sediment cores (with 63-435 cm thicknesses). which C-14 were collected at water depths ranging from 62 to 245 m. C-14 ages of base sections in three cores (11.585, 11.845 and 24.915 ka BP) and upward fining of grain size in the cores suggest that these sediments must have been deposited since the sea-level lowstand at about 12 ka BP, when the conditions in the Marmara Sea began to change from lacustrine to the present marine phase. With some exceptions, siliciclastic mud (silt + clay > 90%) with low carbonate contents (< 15% CaCO3) is the dominant sediment type covering the floor of the canyon. The high organic carbon contents (1-2%) with slight downcore-increasing tendencies reflect higher primary organic productivities towards the early Holocene. Faults, sedimentation deformation structures, and submarine slides or stumps observed on seismic profiles, varying elevations of dated lowstand palaeoshores and low water contents (19-25%) of sediments at some sites together strongly indicate the important effect of neotectonics on sedimentation in this canyon. On the seismic profiles at least four stratigraphic units were recognized overlying the pre-Miocene basement. which indicate not only the effects of faulting and folding but also changing conditions and related depositional environments in and around the canyon. Geological evolution and thus the sea-floor morphology of the Sarkoy Canyon is controlled by both regional Plio-Quaternary tectonics and global Quaternary sea-level changes

The effects of the North Anatolian Fault zone on the latest connection between Black Sea and Sea of Marmara

The development of the Strait of Istanbul is also one of the principal results of the tectonics which led to the evolution of the North Anatolian Fault Zone (NAFZ) in the Marmara Region 3.7 Ma ago. High resolution seismic profiles from the Marmara entrance of the Strait of Istanbul show a folding which occurred after the deposition of the parallel reflected Tyrrhenian sediments. Over the Tyrrhenian strata, a fondoform zone of a deltaic sequence and marine sediments of the latest sea level rising are present. These sediments also display syn-depositional folding. This situation implies that a local compressional stress field was created over the area probably since the Wurm Glacial age. This recent variation of the tectonic regime in the northern shelf of the Sea of Marmara may indicate a significant change in the development of the NAFZ through the Sea of Marmara. This variation of evolution of the NAFZ affected the latest development of the Strait of Istanbul via clockwise rotation of the Istanbul and Kocaeli peninsulas by right-lateral shearing between two zone bounding faults. This rotation has led to the development of NNE-SSW left-lateral faults in the Strait of Istanbul and local compressional and tensional areas explaining the compressional structures seen in the southern entrance of the Strait of Istanbul. Therefore, the latest Mediterranean-Black Sea connection was established by means of the sufficient deepening of the Bosphorus channel by a variation in the evolution of NAFZ through the Sea of Marmara. (C) 2002 Elsevier Science B.V. All rights reserved

Late Quaternary sedimentation and tectonics in the submarine Sarkoy Canyon, western Marmara Sea (Turkey)

WOS: 000267235500011Influences of tectonics and late Quaternary sea-level changes on sedimentation in the submarine Sarkoy Canyon, western Marmara Sea (Turkey) were investigated using a total of 37 seismic reflection profiles and 12 gravity sediment cores (with 63-435 cm thicknesses). which C-14 were collected at water depths ranging from 62 to 245 m. C-14 ages of base sections in three cores (11.585, 11.845 and 24.915 ka BP) and upward fining of grain size in the cores suggest that these sediments must have been deposited since the sea-level lowstand at about 12 ka BP, when the conditions in the Marmara Sea began to change from lacustrine to the present marine phase. With some exceptions, siliciclastic mud (silt + clay > 90%) with low carbonate contents (< 15% CaCO3) is the dominant sediment type covering the floor of the canyon. The high organic carbon contents (1-2%) with slight downcore-increasing tendencies reflect higher primary organic productivities towards the early Holocene. Faults, sedimentation deformation structures, and submarine slides or stumps observed on seismic profiles, varying elevations of dated lowstand palaeoshores and low water contents (19-25%) of sediments at some sites together strongly indicate the important effect of neotectonics on sedimentation in this canyon. On the seismic profiles at least four stratigraphic units were recognized overlying the pre-Miocene basement. which indicate not only the effects of faulting and folding but also changing conditions and related depositional environments in and around the canyon. Geological evolution and thus the sea-floor morphology of the Sarkoy Canyon is controlled by both regional Plio-Quaternary tectonics and global Quaternary sea-level changes

On the origin of the Bosphorus

The Palaeozoic-Upper Cretaceous basement palaeomorphology of the Bosphorus (the Strait of Istanbul) bears the evidence of a valley of a palaeostream running to the Black Sea in the north, a palaeobasin deeper than -160 m opening to the Sea of Marmara in the south, and a barrier between these two features. This suggest that the northern part of the Bosphorus was formed mainly by fluvial activity, whereas the southern part developed as a basin by faulting. The recent sediment thickness exceeds 130 m in the basin, indicating that the southern part of the Bosphorus was once essentially depositional rather than an erosional