Near-infrared (NIR) spectra of apple samples were submitted in this paper to principal component analysis (PCA) and successive projections algorithm (SPA) to conduct variable selection. Three pattern recognition methods, backpropagation neural network (BPNN), support vector machine (SVM), and extreme learning machine (ELM), were applied to establish models for distinguishing apples of different varieties and geographical origins. Experimental results show that ELM models performed better on identifying apple variety and geographical origin than others. Especially, the SPA-ELM model could reach 98.33% identification accuracy on the calibration set and 96.67% on the prediction set. This study suggests that it is feasible to identify apple variety and cultivation region by using NIR spectroscopy.

Water flow and silt movement in a double-suction centrifugal pump were simulated using an Euler–Lagrange multiphase flow model. Blade erosion rates were predicted using a particle erosion model and the influence of inlet and outlet shapes on silt abrasion was analyzed. The results show: the inlet relative velocity is larger on the suction side than on the pressure side; the blade inlet and outlet are severely silt abraded and the average erosion rate is always larger on the suction side than on the pressure side; the inlet relative velocity and the impact angle are two important influencing factors, and can be controlled by changing the inlet and outlet shapes to reduce erosion rate and increase pump efficiency. In this simulation, two effective means of reducing erosion rates are decreasing the hydraulic loss and increasing pump head and pump efficiency.

No abstract

No abstract

Climate change predominated by warming over the past decades has affected plant biodiversity, distribution, and ecosystem functioning in alpine grasslands. Yet, little is known about the interactive effect of climate change and grazing on biodiversity and ecosystem functioning. Here, we conducted a vegetation translocation experiment (ten soil‐vegetation blocks were translocated from high‐altitudinal site 3,245 m to low‐altitudinal site 3,045 m) combined with grazing treatment in an alpine meadow on the Tibetan Plateau. The results showed that (a) translocation induced effect of climate change from harsh, high‐altitudinal site to benign, low‐altitudinal site significantly promoted species richness, and density of asexual and sexual seedling, with an increase in the proportion of asexual recruitment to sexual recruitment; (b) grazing decreased the proportion of asexual seedling to sexual recruitment within community, led to a shift in the dominant plant functional groups from graminoids and legumes to forbs; and (c) grazing partly offset the increased species richness of seedling, but not seedling density, induced by climate change. These findings suggest that moderate grazing may buffer the effect of climate change on the plant community composition, and thus, functional role in alpine meadows. Further understanding the influence of climate change on grassland ecosystems needs to consider the non‐additive effect of grazing and climate change to sustainability of grassland services.