Slat Noise Suppression Using Upstream Mass Injection

A new approach,mass injection near the slat cusp,is proposed for the suppression of slat noise.The mechanism and efciency of the slat noise suppression using upstream mass injection are numerically studied with hybrid Reynolds-averaged Navier-Stokes simulation/Large eddy simulation(RANS/LES)of a three-component high-lift model.Ffowcs-Williams and Hawking(FW-H)integration is employed to obtain far-field acoustic characteristics.Results show that with injection,aerodynamic capability of the high-lift devices is sustained.In addition,a considerable noise reduction is observed in the downward direction.With detailed analysis of the time-averaged and instantaneous flow fields,two mechanisms are identified as the reason accounting for the noise suppression:upstream mass injection significantly reduces the scale and strength of the vortices stemming from the cusp;the shear layer is lifted up,which relieves the shear layer impingement on the slat lower surface.

Observation and analysis of halo current in EAST

Plasma in a typically elongated cross-section tokamak （for example, EAST） is inherently unstable against vertical displacement. When plasma loses the vertical position control, it moves downward or upward, leading to disruption, and a large halo current is generated helically in EAST typically in the scrape-off layer. When flowing into the vacuum vessel through in-vessel components, the halo current will give rise to a large J × B force acting on the vessel and the in-vessel components. In EAST VDE experiment, part of the eddy current is measured in halo sensors, due to the large loop voltage. Primary experimental data demonstrate that the halo current first lands on the outer plate and then flows clockwise, and the analysis of the information indicates that the maximum halo current estimated in EAST is about 0.4 times the plasma current and the maximum value of TPF × Ih/Ip0 is 0.65, furthermore Ih/Ipo and TPF × Ih/Ipo tend to increase with the increase of Ip0. The test of the strong gas injection system shows good success in increasing the radiated power, which may be effective in reducing the halo current.

Determination of Variance of Secondary Metabolites in Lettuces Grown Under Different Light Sources by Flow Injection Mass Spectrometric(FIMS)Fingerprinting and ANOVA-PCA

Lettuce(Lactuca sativa L.)is one of the most consumed vegetables in the world and different management practice can result in considerable variability of the secondary metabolites.Flow injection mass spectrometry(FIMS)combined with analysis of variance-principle component analysis(ANOVA-PCA)was used to study differences in the secondary metabolites originat-ing from different lighting conditions(Sunlight,white light,and florescent light)and lettuce varieties(Romaine and Lollo Rossa).Ultra-high-performance liquid chromatography-high-resolution accurate mass spectrometry was used for putative marker compound identification.Quinic acid,caffeic acid,chlorogenic acid,L-chicoric acid,and quercetin malonyl gluco-side varied significantly for Romaine lettuce grown under different light conditions.The study showed that the combination of FIMS fingerprinting and ANOVA-PCA can be a useful tool for the characterization of the sources of variance in plant materials regarding to genetic,environmental,and management factors.