Nanoparticles are expected to play a vital role in the management of future plant diseases, and they are expected to provide an environmentally friendly alternative to traditional synthetic fungicides. In the present study, silver nanoparticles (AgNPs) were green synthesized through the mediation by using the endophytic bacterium Pseudomonas poae strain CO, which was isolated from garlic plants (Allium sativum). Following a confirmation analysis that used UV–Vis, we examined the in vitro antifungal activity of the biosynthesized AgNPs with the size of 19.8–44.9 nm, which showed strong inhibition in the mycelium growth, spore germination, the length of the germ tubes, and the mycotoxin production of the wheat Fusarium head blight pathogen Fusarium graminearum. Furthermore, the microscopic examination showed that the morphological of mycelia had deformities and collapsed when treated with AgNPs, causing DNA and proteins to leak outside cells. The biosynthesized AgNPs with strong antifungal activity were further characterized based on analyses of X-ray diffraction, transmission electron microscopy, scanning electron microscopy, EDS profiles, and Fourier transform infrared spectroscopy. Overall, the results from this study clearly indicate that the biosynthesized AgNPs may have a great potential in protecting wheat from fungal infection.

A greedy non-intrusive reduced order method (ROM) is proposed for parameterized time-dependent problems with an emphasis on problems in fluid dynamics. The non-intrusive ROM (NIROM) bases on a two-level proper orthogonal decomposition (POD) to extract temporal and spatial reduced basis from a set of candidates, and adopts the radial basis function (RBF) to approximate undetermined coefficients of extracted reduced basis. Instead of adopting uniform or random sampling strategies, the candidates are determined by an adaptive greedy approach to minimize the overall offline computational cost. Numerical studies are presented for a two-dimensional diffusion problem as well as a lid-driven cavity problem governed by incompressible Navier-Stokes equations. The results demonstrate that the greedy non-intrusive ROM (GNIROM) predicts the flow field accurately and efficiently.

Abstract:Depended on the analysis of ground snow situation, soil moisture loss speed and soil structure after planting crops of Mu Us Sandy Land remedied with feldspathic sandstone in the fallow period, it is concluded that feldspathic sandstone mixed with sand improved the sand stabilization in the governance of Mu Us Sandy Land in the fallow period. The sandy land remedied with feldspathic sandstone had big snow coverage, 25%-75% higher than normal sand; soil moisture losses slowed down, and moisture content rose by over 3 times; soil structure had been improved, and water stable aggregate content increased by 6.52%-18.04%; survival rate of protection forest increased to 85%; and ground flatness is less than 1%. The above conditions weakened sand rising conditions of Mu Us Sandy Land in the fallow period and formed two protective layers of snow cover and soil frozen layer under cold weather so as to prevent against wind erosion.

After billions of years of natural selection, flying animals with flapping wings have superior flight and mobility capabilities. The aerodynamic characteristics and the propulsion mechanism of bionic wings have attracted a large number of researchers because they will be beneficial to novel bio-inspired micro air or underwater vehicle design. Except the single activities, for fish, birds, and insects, there is a very popular and interesting biological clustering phenomenon known as schooling. Considering the real biological movements in schooling under low Reynolds number, the study of the flow mechanisms and thrust performance of bionic multiflapping wings in different schooling configurations could be applied to the design of future bionic flapping wing aircraft formation. The unsteady flow mechanisms and the thrust performance of three-dimensional multiflapping wings in three different schooling configurations are numerically investigated using the immersed boundary-lattice Boltzmann method with the Chinese TianHe-II supercomputer. The influences of different schooling configurations and individual distances on the thrust performance of multiflapping wings are thoroughly investigated. Numerical results indicate that the individual horizontal distance has great effects on the thrust performance of multiflapping wings in schooling, and the average thrust coefficient of each flapping wing in different schooling configurations at a specific individual horizontal distance is larger than that of the single flapping wing. There is an optimum distance for different schooling configurations, where the individual interaction lead to best propulsion performance. Different from the simple tandem schooling, the closer the individual distance, the better the overall thrust performance obtained for triangle and diamond schooling.

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