Extracts of elephant grass （Penniseturn purpureum） blended with some intensifier halides like ammonium chloride （AMC） and potassium iodide （PTI） were investigated as corrosion inhibitor for mild steel. The corro...Extracts of elephant grass （Penniseturn purpureum） blended with some intensifier halides like ammonium chloride （AMC） and potassium iodide （PTI） were investigated as corrosion inhibitor for mild steel. The corrosion process was monitored in 3.5% HCI by mass loss and electrochemical techniques at 30, 40, 50, 60 and 90 ℃. Addition of AMC and PTI increased the inhibition efficiency with the highest inhibition efficiency obtained with PTI blend- ed extract. The blends behaved as mixed type inhibitors and were spontaneously adsorbed on mild steel surface in exothermic nature. Synergistic parameters of the intensifier ions revealed cooperative effect. Kinetic data treatment indicated increase in energy barrier by intensifier ions. The results demonstrate that elephant grass extract blended with halide ions can act as alternative ecofriendly inhibitor for mild steel at elevated temperatures.展开更多
Rayleigh wave imaging is efficient in estimating the shear- （S） wave velocity in near-surface exploration. The key is to accurately extract the dispersion of Rayleigh wave. We propose a method to calculate the dispe...Rayleigh wave imaging is efficient in estimating the shear- （S） wave velocity in near-surface exploration. The key is to accurately extract the dispersion of Rayleigh wave. We propose a method to calculate the dispersion of the active-source Rayleigh wavefield by using the Aki formulation. The spectrum after the cross correlation of two-channel records in the frequency domain is expressed by the Bessel function. Using the corresponding relation between the zero point of the spectrum real part and the Bessel function root, the phase velocity at the discrete frequency point is obtained and the dispersion curve is extracted. First, the theoretical basis and calculation method used in the active-source Rayleigh wave data are introduced. Then, three sets of theoretical models are calculated by this method and the results are consistent with the theoretical dispersion. Finally, we process a group of real Rayleigh wave data and obtain the phase velocity profiles and compared them with the results obtained by the multichannel surface wave analysis method. The effectiveness and applicability of the Aki method in active-source data processing are verified. Compared with multichannel wave processing, the advantage of the Aki method lies in the use of two- channel data in a single-shot record. When the number of acquisition channels in a shot gathers is insufficient or there is a bad channel, the quality of the extracted dispersion is guaranteed.展开更多
基金financial support provided by World Bank Robert S.Mc Namara Fellowship Program 2015 to carry out this research abroad
文摘Extracts of elephant grass （Penniseturn purpureum） blended with some intensifier halides like ammonium chloride （AMC） and potassium iodide （PTI） were investigated as corrosion inhibitor for mild steel. The corrosion process was monitored in 3.5% HCI by mass loss and electrochemical techniques at 30, 40, 50, 60 and 90 ℃. Addition of AMC and PTI increased the inhibition efficiency with the highest inhibition efficiency obtained with PTI blend- ed extract. The blends behaved as mixed type inhibitors and were spontaneously adsorbed on mild steel surface in exothermic nature. Synergistic parameters of the intensifier ions revealed cooperative effect. Kinetic data treatment indicated increase in energy barrier by intensifier ions. The results demonstrate that elephant grass extract blended with halide ions can act as alternative ecofriendly inhibitor for mild steel at elevated temperatures.
基金This research was jointly supported by the National Natural Science Foundation of China （No.s 41374145 and 41004043） and the Natural Science Basic Research Plan in Shaanxi Province of China （No. 2016JM4003）.
文摘Rayleigh wave imaging is efficient in estimating the shear- （S） wave velocity in near-surface exploration. The key is to accurately extract the dispersion of Rayleigh wave. We propose a method to calculate the dispersion of the active-source Rayleigh wavefield by using the Aki formulation. The spectrum after the cross correlation of two-channel records in the frequency domain is expressed by the Bessel function. Using the corresponding relation between the zero point of the spectrum real part and the Bessel function root, the phase velocity at the discrete frequency point is obtained and the dispersion curve is extracted. First, the theoretical basis and calculation method used in the active-source Rayleigh wave data are introduced. Then, three sets of theoretical models are calculated by this method and the results are consistent with the theoretical dispersion. Finally, we process a group of real Rayleigh wave data and obtain the phase velocity profiles and compared them with the results obtained by the multichannel surface wave analysis method. The effectiveness and applicability of the Aki method in active-source data processing are verified. Compared with multichannel wave processing, the advantage of the Aki method lies in the use of two- channel data in a single-shot record. When the number of acquisition channels in a shot gathers is insufficient or there is a bad channel, the quality of the extracted dispersion is guaranteed.
