Conceptual Design for Long-Endurance Convertible Unmanned Aerial System

This research is aimed at analysing the effect of design parameters on critical aerodynamic performance of convertible unmanned aerial vehicle (UAV) with vertical take-off and landing (VTOL) capabilities and providing a sizing tool for its conceptual design. The research was based on new aerodynamic models specifically developed and validated for convertible aircraft, performed using mission-based optimisation techniques. To accommodate a wide range of convertible aircraft configurations, a non-linear lifting-line method was used to efficiently analyse different combinations of lifting surface and propeller arrangements. Propeller loads were calculated using a blade element momentum approach and corrected for high incidence angle conditions according to numerical and experimental studies. Propeller-wing interactions were considered by modifying local boundary conditions at wing sections immersed in propeller slipstream. Previous studies have suggested that the design of convertible aircraft is sensitive to typical mission requirements, notably the endurance breakdown between near-hover flight and cruise flight. A clear sizing law for wing and propeller according to given mission specification could greatly improve the understanding of compromises between hover and high speed flight

Genetic architecture of common bunt resistance in winter wheat using genome-wide association study

Background: Common bunt (caused by Tilletia caries and T. foetida) has been considered as a major disease in wheat (Triticum aestivum) following rust (Puccinia spp.) in the Near East and is economically important in the Great Plains, USA. Despite the fact that it can be easily controlled using seed treatment with fungicides, fungicides often cannot or may not be used in organic and low-input fields. Planting common bunt resistant genotypes is an alternative. Results: To identify resistance genes for Nebraska common bunt race, the global set of differential lines were inoculated. Nine differential lines carrying nine different genes had 0% infected heads and seemed to be resistant to Nebraska race. To understand the genetic basis of the resistance in Nebraska winter wheat, a set of 330 genotypes were inoculated and evaluated under field conditions in two locations. Out of the 330 genotypes, 62 genotypes had different degrees of resistance. Moreover, plant height, chlorophyll content and days to heading were scored in both locations. Using genome-wide association study, 123 SNPs located on fourteen chromosomes were identified to be associated with the resistance. Different degrees of linkage disequilibrium was found among the significant SNPs and they explained 1.00 to 9.00% of the phenotypic variance, indicating the presence of many minor QTLs controlling the resistance. Conclusion: Based on the chromosomal location of some of the known genes, some SNPs may be associated with Bt1, Bt6, Bt11 and Bt12 resistance loci. The remaining significant SNPs may be novel alleles that were not reported previously. Common bunt resistance seems to be an independent trait as no correlation was found between a number of infected heads and chlorophyll content, days to heading or plant height