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Global sensitivity analysis plays an important role in robustness optimization design of aero-engine fuel gear pumps to investigate how input parameters uncertainties contribute to performances uncertainties. In this paper, inspired by the Leave-One-Out method, an advanced Polynomial Chaos Expansion (PCE) method equipped with Adaptive design of both training Points and polynomial Order, denoted as APO-PCE, is proposed to efficiently estimate the variance-based sensitivity indices. A novel active learning strategy is developed for identifying the optimal candidate sample point to adaptively design training points and simultaneously update the polynomial order. Input parameters, including rotational speed, inlet pressure, outlet pressure, and gear tip clearance, are reasonably characterized as nine convenient sampling Gaussian variables by probabilistic modeling and Karhuben–Loève expansion. The results show that the proposed APO-PCE method is superior to the classical PCE method, and the uncertainties of rotational speed, inlet pressure, and outlet pressure are the main factors for the uncertainties of supply performances and flow field characteristics, while the gear tip clearance uncertainty only affects the flow loss at lower rotational speed. [ABSTRACT FROM AUTHOR]

Here, we report the discovery of two viruses associated with a disease characterized by severe diarrhea on a large-scale goat farm in Jilin province. Electron Microscopy observations revealed two kinds of virus particles with the sizes of 150–210 nm and 20–30 nm, respectively. Detection of 276 fecal specimens from the diseased herds showed the extensive infection of peste des petits ruminants virus (63.77%, 176/276) and caprine enterovirus (76.81%, 212/276), with a co-infection rate of 57.97% (160/276). These results were partially validated with RT-PCR, where all five PPRV-positive and CEV-positive specimens yielded the expected size of fragments, respectively, while no fragments were amplified from PPRV-negative and CEV-negative specimens. Moreover, corresponding PPRV and CEV fragments were amplified in PPRV and CEV double-positive specimens. Histopathological examinations revealed severe microscopic lesions such as degeneration, necrosis, and detachment of epithelial cells in the bronchioles and intestine. An immunohistochemistry assay detected PPRV antigens in bronchioles, cartilage tissue, intestine, and lymph nodes. Simultaneously, caprine enterovirus antigens were detected in lung, kidney, and intestinal tissues from the goats infected by the peste des petits ruminants virus. These results demonstrated the co-infection of peste des petits ruminants virus with caprine enterovirus in goats, revealing the tissue tropism for these two viruses, thus laying a basis for the future diagnosis, prevention, and epidemiological survey for these two virus infections. [ABSTRACT FROM AUTHOR]

Geometric machining errors in the blade profile and variable operating conditions in the extreme operating environment are primary factors leading to the uncertainties in pump performance. This paper presents an analysis of uncertainties of fuel centrifugal pumps by modeling the geometry uncertainty in blade machining based on the Karhunen–Loève (KL) expansion and using a polynomial chaos expansion (PCE) model. First, the geometric uncertainty in the blade machining is described by the KL expansion in three sections and a stochastic simulation of the blade geometry is performed. Then, a PCE surrogate model is trained based on the least angle regression method and validated by the bootstrap method to quantify the uncertainties of performance indices. Finally, the influence mechanism and relative importance of each input uncertainty parameter are investigated using a quasi-Monte Carlo simulation method. The results show that the KL expansion of the blade profile uses the random vector perturbation superposition of three stream surface, achieving the dimensional reduction in the blade machining error. The PCE surrogate model, trained with a dataset of 3 × 106 sample points, exhibits excellent fit, and the R-squared and adjusted R-squared for head coefficient and efficiency are both above 80%. The variance of parameter control points of the reconstructed flow field is less than 0.002. The uncertainties in both operating conditions and parameters have an influence on the distribution of the global flow field, while the influence of the uncertainty in machining error on the global flow field mainly concentrates on the power-generating positions of the blade. [ABSTRACT FROM AUTHOR]

To promote the sustainable development of the liquor/ethanol industry and environment protection, alternative ways to dispose of anaerobic digestion residue (ADR) are urgently required. This research aims at studying the effects of different residence times (RTs) (30, 60 and 120 min) and heating rates (HR) (2.5, 5.0 and 10.0°C min-1) under 700°C on characteristics of ADR biochar as well as the optimization of ammonium (NH4+) adsorption. Results showed that, with the increasing RT and HR, the aromaticity as well as the content of fixed carbon and elemental carbon of ADR biochar increased, but the pyrolysis yield, volatile matter content, elemental hydrogen, oxygen and polarity decreased. Biochar prepared at 60 min and 5.0°C min-1 under 700°C presented the best development of orderly and honeycomb shape structures, highest specific surface area and maximal amount of NH4+ adsorption (3.15 mg N g-1). The multilayer heterogeneous adsorption process dominated the NH4+ adsorption behaviour. And the maximal amount of NH4+ adsorption was achieved with 4 g biochar L-1 at pH 11.0 along with the order of the competitive effect of K+ > Na+ > Ca2+ > Mg2+. Furthermore, NH4+ adsorption was exothermic. Thus, the present study demonstrated that ADR biochar has potential to adsorb NH4+ from NH4+ polluted water to meet environmental standards. [ABSTRACT FROM AUTHOR]

The passage of a fluid particle (bubble or a drop) past an obstruction in a rectangular channel is examined by numerical simulation, focusing on the disruption of the wake and the trajectory of the fluid particle. The flow is laminar, and the wake is initially steady. The obstruction is relatively large compared to the height of the channel. The problem is defined by the capillary number (Ca) and the Reynolds number (Re), the density (ηρ) and viscosity (ημ) ratios, and the relative size of the fluid particle (ηd). Simulations of three-dimensional flows are used to examine several combinations of these parameters. The results show that the motion of a drop is nearly independent of the wake downstream of the obstruction, but bubbles may get temporarily trapped in it. Drops also tend to block the background flow, while bubbles may accelerate it. It is found that a bubble of comparable or smaller size than the constriction can pass through the constriction intact without getting trapped. An increase in Ca and Re leads to bubbles passing through the constriction at a faster speed and move further downstream before being caught by the wake. Simulations of two-dimensional flows for a relatively larger range of Ca and Re are performed to obtain a flow regime diagram. The results show that relatively rigid particles (low Ca) tend to be temporarily trapped in the wake, while more deformable particles (higher Ca) pass without being trapped at lower Reynolds numbers but break up at higher Reynolds numbers. The influence of the obstruction geometry is also examined. [ABSTRACT FROM AUTHOR]