Optimized wake-superposition approach for multiturbine wind farms.

Optimizing the wind farm layout requires accurately quantifying the wind-turbine wake distribution to minimize interference between wakes. Thus, the accuracy of wind turbine wake superposition models is critical. The sum of squares (SS) model is currently touted as the most accurate, but its application in engineering is hampered by its overestimation of the velocity deficit of the mixed wake. Therefore, previous work relied on approximate power calculations for performing optimization. The physical meaning of the SS model is unclear, which makes optimization difficult. In this study, a univariate linear correction idea is proposed based on the linear increase phenomenon of the SS method error. The unknown coefficients are obtained by fitting experimental data. The results demonstrate that the proposed method can accurately quantify the full-wake two-dimensional distribution of the mixed wake.

The tree shrew is a promising model for the study of influenza B virus infection.

BACKGROUND: Influenza B virus is a main causative pathogen of annual influenza epidemics, however, research on influenza B virus in general lags behind that on influenza A viruses, one of the important reasons is studies on influenza B viruses in animal models are limited. Here we investigated the tree shrew as a potential model for influenza B virus studies. METHODS: Tree shrews and ferrets were inoculated with either a Yamagata or Victoria lineage influenza B virus. Symptoms including nasal discharge and weight loss were observed. Nasal wash and respiratory tissues were collected at 2, 4 and 6 days post inoculation (DPI). Viral titers were measured in nasal washes and tissues were used for pathological examination and extraction of mRNA for measurement of cytokine expression. RESULTS: Clinical signs and pathological changes were also evident in the respiratory tracts of tree shrews and ferrets. Although nasal symptoms including sneezing and rhinorrhea were evident in ferrets infected with influenza B virus, tree shrews showed no significant respiratory symptoms, only milder nasal secretions appeared. Weight loss was observed in tree shrews but not ferrets. V0215 and Y12 replicated in all three animal (ferrets, tree shrews and mice) models with peak titers evident on 2DPI. There were no significant differences in peak viral titers in ferrets and tree shrews inoculated with Y12 at 2 and 4DPI, but viral titers were detected at 6DPI in tree shrews. Tree shrews infected with influenza B virus showed similar seroconversion and respiratory tract pathology to ferrets. Elevated levels of cytokines were detected in the tissues isolated from the respiratory tract after infection with either V0215 or Y12 compared to the levels in the uninfected control in both animals. Overall, the tree shrew was sensitive to infection and disease by influenza B virus. CONCLUSION: The tree shrew to be a promising model for influenza B virus research.