Gas emissions and active tectonics within the submerged section of the North Anatolian Fault zone in the Sea of Marmara

The submerged section of the North Anatolian fault within the Marmara Sea was investigated using acoustic techniques and submersible dives. Most gas emissions in the water column were found near the surface expression of known active faults. Gas emissions are unevenly distributed. The linear fault segment crossing the Central High and forming a seismic gap – as it has not ruptured since 1766, based on historical seismicity, exhibits relatively less gas emissions than the adjacent segments. In the eastern Sea of Marmara, active gas emissions are also found above a buried transtensional fault zone, which displayed micro-seismic activity after the 1999 events. Remarkably, this zone of gas emission extends westward all along the southern edge of Cinarcik basin, well beyond the zone where 1999 aftershocks were observed. The long term monitoring of gas seeps could hence be highly valuable for the understanding of the evolution of the fluid-fault coupling processes during the earthquake cycle within the Marmara Sea

Persistent Cell-Autonomous Circadian Oscillations in Fibroblasts Revealed by Six-Week Single-Cell Imaging of PER2::LUC Bioluminescence

Biological oscillators naturally exhibit stochastic fluctuations in period and amplitude due to the random nature of molecular reactions. Accurately measuring the precision of noisy oscillators and the heterogeneity in period and strength of rhythmicity across a population of cells requires single-cell recordings of sufficient length to fully represent the variability of oscillations. We found persistent, independent circadian oscillations of clock gene expression in 6-week-long bioluminescence recordings of 80 primary fibroblast cells dissociated from PER2::LUC mice and kept in vitro for 6 months. Due to the stochastic nature of rhythmicity, the proportion of cells appearing rhythmic increases with the length of interval examined, with 100% of cells found to be rhythmic when using 3-week windows. Mean period and amplitude are remarkably stable throughout the 6-week recordings, with precision improving over time. For individual cells, precision of period and amplitude are correlated with cell size and rhythm amplitude, but not with period, and period exhibits much less cycle-to-cycle variability (CV 7.3%) than does amplitude (CV 37%). The time series are long enough to distinguish stochastic fluctuations within each cell from differences among cells, and we conclude that the cells do exhibit significant heterogeneity in period and strength of rhythmicity, which we measure using a novel statistical metric. Furthermore, stochastic modeling suggests that these single-cell clocks operate near a Hopf bifurcation, such that intrinsic noise enhances the oscillations by minimizing period variability and sustaining amplitude

Modeling and analysis of a nonlinear adaptive filter control for interline unified power quality conditioner

Abant Izzet Baysal Universitesi;Cankiri Karatekin Universitesi2013 4th International Conference on Power Engineering, Energy and Electrical Drives, POWERENG 2013 --13 May 2013 through 17 May 2013 -- Istanbul --In this paper, one of the known interline custom power devices named Interline Unified Power Quality Conditioner (IUPQC) is improved for various power quality disturbances and modeled in PSCAD/EMTDC. The developed topology can be used for simultaneous compensation of voltage and current imperfections in a multibus/multifeeder system. The proposed IUPQC is designed for medium voltage level (11 kV) and effective Enhanced Phase Locked Loop (EPLL) based control technique is used to detect and extract the PQ disturbances. The performance of Series Compensator of IUPQC is evaluated through extensive simulations for mitigating unbalanced voltage sags with phase jumps and interruption. The performance of Shunt Compensator of IUPQC is also tested for harmonic and reactive power compensation that are not investigated before in literature. It is verified that IUPQC which is connected to two feeders, can compensate current and voltage distortions succesfully in these feeders according to the results obtained using PSCAD/EMTDC. © 2013 IEEE

Review of hybrid active power filter topologies and controllers

Abant Izzet Baysal Universitesi;Cankiri Karatekin Universitesi2013 4th International Conference on Power Engineering, Energy and Electrical Drives, POWERENG 2013 --13 May 2013 through 17 May 2013 -- Istanbul --Hybrid active power filter (HAPF) consisting of passive filter and active filter in various configurations to each other has now become preferred technology for harmonic compensation in two wire, three wire and four wire ac power networks with nonlinear loads. This paper presents a detailed survey of hybrid active power filters considering converter topologies, supply system and passive filter type. In addition, the control strategies are discussed in detail. The main aim of this paper is to provide a broad perspective on the status of HAPF technology to researchers and application engineers dealing with power quality. More than eighty research papers are reviewed and classified into categories and subcategories. © 2013 IEEE