RESUMEN
In this paper, we analyze the effects of finite correlation time (noise color) of combustion noise on noise-induced coherence and early warning indicators (EWIs) via numerical and experimental studies. We consider the Rijke tube as a prototypical combustion system and model combustion noise as an additive Ornstein-Uhlenbeck process while varying noise intensity and correlation time. We numerically investigate corresponding effects on coherence resonance and multi-fractal properties of pressure fluctuations. Subsequently, we experimentally validate results and elucidate the influence of noise color and intensity on trends in coherence resonance and multi-fractal measures that can be expected in a practical scenario using an electroacoustic simulator. We find that the coherence factor, which quantifies the relative contribution of coherent oscillations in a noisy signal, increases as the system approaches the thermoacoustic instability-irrespective of the correlation time. It works at most levels of combustion noise (except for too low and too high noise levels). The Hurst exponent reduces as the system approaches thermoacoustic instability only when the correlation time is small. These results have implications on the prediction and monitoring of thermoacoustic instability in practical combustors.
RESUMEN
The present investigation deals with the study on the phytotoxicity of leachates obtained from Eveready Industries India Ltd., Flashlight Lucknow. Analysis of heavy metals in leachates and effluent showed that leachates contained heavy metals in the following order Ni>Zn>Cr>Cu, whereas effluent mainly contained Hg in high (0.22 microg ml(-1)) concentration. Phytotoxicity of leachates on different parameters of P. sativum was studied in pot experiment. The results revealed that leachate induced concentration dependent decline in the germination percentageand protein content. However, lower concentration of leachate (5-20%) showed stimulatory effect on the chlorophyll and carotenoid content. A continuous dumping of such solid waste in the vicinity of populated area will ultimately cause surface and ground water pollution due to leaching of the waste.