Plant-Back Intervals of Imicyafos Based on Its Soil Dissipation and Plant Uptake for Rotational Cultivation of Lettuce and Spinach in Greenhouse

The plant-back intervals (PBIs) of imicyafos were investigated for rotational cultivation of lettuce and spinach in greenhouses. Imicyafos dissipation in soil and its plant uptake were evaluated by liquid chromatography-tandem mass spectrometry. Bioconcentration ratios (BCRs) were calculated by comparing the residues in plants to the initial residue in soil. The BCRs were used to calculate the soil acceptable residues (SARs) transferable to plants at the Positive List System (PLS) level. The number of days, PBIs for reaching SARs were obtained from the dissipation equation for imicyafos in soil. In soil, imicyafos followed first order dissipation kinetics (R2 = 0.975) with a half-life of 40.8 days. The BCRs ranged from 0.041 to 0.469 in the edible leaf parts of lettuce and 0.006 to 0.134 in those of spinach. The SARs ranged from 0.021 to 0.244 for lettuce and 0.075 to 1.667 mg kg−1 for spinach. The PBIs of imicyafos were estimated to be 213.9 to 357.3 days for lettuce and 100.8 to 283.6 days for spinach. This study suggests at least a minimum 1-year interval after the final application of imicyafos as a management method that complies with the PLS for the rotational cultivation of lettuce and spinach.

Analysis on Vibration Characteristics of Air Film Damping with Open Boundaries

Air film damping (AFD) has been a research focus for the fatigue damage suppression problem of aeroengine blade decades ago; however significant progress has not been made in the past decade. In this paper, we present a theoretical model and experimental analysis about this technology. The dissipation mechanism of the AFD is established by assumption that the viscous gas inside the thin air film is Poiseuille flow and the energy dissipation equation of AFD with open boundaries is deduced and evaluated. Blade simulated testing specimens are designed. The vibration measurements are performed by RC-3000 vibration exciter and detected by applying the contactless laser vibrometer system. The theoretical results consist with the experimental results, and both show that AFD appears promising performance in vibration suppression. We also present how the structure parameters, such as installation position, air film length and thickness, and thin skin thickness, influence the vibration suppression effect.

Finite volume discretisation for the one-dimensional convection diffusion-dissipation equation

This paper is devoted to analysis of a finite volume scheme for a one-dimensional convection-diffusion-dissipation equation having application in pollution of water table. We analyse a scheme corresponding to a semi-descretization, also called method of lines. Results of umerical experiments using this approach are reported.

Analysis for the Stability of Irregular Wedge on Slope and its Engineering Application

Energy dissipation equation is obtained from the virtual work principle. By assuming different initiative sliding directions, methods of upper bound solution and classical solution for rock wedge stability are deduced. The computational formulas of safety factor indicate that the safety factor of wedge is depended on the areas of sliding surfaces and the volume of the wedge rather than the shape of the slope when the attitude and strength of discontinuities is given. Therefore the current wedge method can be improved to overcome the weakness that the current method is inapplicable when the slope shape is greatly rugged and the wedge is surrounded by more than three discontinuities. As an example, the improved method is applied in the left bank slope of Baihetan hydropower station. The calculation results obtained by the improved methods is more reasonable and credible.