Aerodynamic analysis for hybrid electric distributed propulsion aircraft

In a bid to meet the requirements on drag reduction, consumer demands and the latest regulations on carbon emissions and noise, aircraft manufacturers are continually looking at new technologies to improve performance. The aerospace industry is also looking to achieve the mutual benefit of combining existing technologies with new concepts to enhance transonic aerodynamic performance. With the power of modern computing, scientists and engineers can conduct Computational Fluid Dynamics (CFD) simulations for various aircraft configurations to test potential improvements by saving both prototyping and experimental costs. This research project considers the Hybrid Electric Distributed Propulsion (HEDP) concept with under (UWN) and over-wing nacelle (OWN) configurations for large transonic transport aircraft. It examines the potential benefits of integrated UWN and OWN configurations including: (1) the effect of the fan in controlling rear adverse pressure gradients to maintain a safe operating margin between cruise and buffet, (2) providing Mach flexibility, and (3) potential performance benefits of an integrated fan design compared with traditional under-wing podded engines that can generate strong shock waves in gully regions at off-design conditions. The research also considers a design approach to improve the drag standard of a typical supercritical aerofoil by optimising its shape to minimise/eliminate the strength of shock waves. This was achieved by combining the well-known CST aerofoil parametrisation method and a four-dimensional Optimal Latin Hypercube Design of Experiments. This research project relies on numerical analysis to investigate the flow mechanism associated with the aerodynamic performance of HEDP for both nacelle configurations. Through this research project, the distributed UWN configuration provides 87.46% in sectional drag reduction compared to the conventional podded engine configuration. Similarly, drag is reduced by 40.96% for the OWN configuration. However, it should be noted that the two-dimensional (2D) analysis of the conventional podded engine configuration is not truly representative of a three-dimensional (3D) flow field. Both of these results are achieved with an increase in aerofoil thickness which would be expected to also contribute to a wing weight reduction. Further 3D computational research, and experimental verification is recommended for future research activities. The scope of this study was largely two-dimensional but it will be important for next steps in this research direction to account for more complex 3D effects, such as cross-flow and swirl; these considerations will be important to fully exploit potential improvements in aerodynamic performance for transonic wing designs

Factors affecting mobile gaming adoption - A study of Chinese users and contexts

Objective of the Study The objective of the study was to discover the main factors affecting mobile gaming in the Chinese context. The theoretical base of the study was built on the Technology Acceptance Model (TAM) and its later revisions. Special attention was paid on recent TAM studies on mobile gaming in China or other East Asian areas. In addition, to bring the TAM theory closer to marketing applications, the study produced clusters from the respondent data in order to identify different consumer segments and divide the users into them. Methodology The data for the study was collected in the spring of 2011 through a quantitative online survey, which was distributed on a Finnish game company’s Chinese microblog sites and other relevant Chinese online channels. A total of 492 usable responses were obtained for further analysis. Four main analytical methods were used in the study: factor analysis, regression analysis, cluster analysis and cross-tabulation. Findings and Conclusions The study identified four key factors that affect mobile gaming adoption in China: Perceived Ease of Use, Perceived Enjoyment, Social Influence and Flow. Of these factors, perceived enjoyment had the largest effect on adoption, followed by social influence, flow and lastly, ease of use. The factors also seemed to interact with each other. For example, social influence has a strong effect on perceived enjoyment, and the link between perceived enjoyment and flow is also very strong. Marketing-wise, the cluster analysis identified five user or potential user segments. Their profiles were interpreted based on the clustering solutions and additional cross-tabulation with background variables age, gender, experience and use context

Pseudo-Separation for Assessment of Structural Vulnerability of a Network

Based upon the idea that network functionality is impaired if two nodes in a network are sufficiently separated in terms of a given metric, we introduce two combinatorial \emph{pseudocut} problems generalizing the classical min-cut and multi-cut problems. We expect the pseudocut problems will find broad relevance to the study of network reliability. We comprehensively analyze the computational complexity of the pseudocut problems and provide three approximation algorithms for these problems. Motivated by applications in communication networks with strict Quality-of-Service (QoS) requirements, we demonstrate the utility of the pseudocut problems by proposing a targeted vulnerability assessment for the structure of communication networks using QoS metrics; we perform experimental evaluations of our proposed approximation algorithms in this context

Inputs to the Dorsal Striatum of the Mouse Reflect the Parallel Circuit Architecture of the Forebrain

The basal ganglia play a critical role in the regulation of voluntary action in vertebrates. Our understanding of the function of the basal ganglia relies heavily upon anatomical information, but continued progress will require an understanding of the specific functional roles played by diverse cell types and their connectivity. An increasing number of mouse lines allow extensive identification, characterization, and manipulation of specified cell types in the basal ganglia. Despite the promise of genetically modified mice for elucidating the functional roles of diverse cell types, there is relatively little anatomical data obtained directly in the mouse. Here we have characterized the retrograde labeling obtained from a series of tracer injections throughout the dorsal striatum of adult mice. We found systematic variations in input along both the medial–lateral and anterior–posterior neuraxes in close agreement with canonical features of basal ganglia anatomy in the rat. In addition to the canonical features we have provided experimental support for the importance of non-canonical inputs to the striatum from the raphe nuclei and the amygdala. To look for organization at a finer scale we have analyzed the correlation structure of labeling intensity across our entire dataset. Using this analysis we found substantial local heterogeneity within the large-scale order. From this analysis we conclude that individual striatal sites receive varied combinations of cortical and thalamic input from multiple functional areas, consistent with some earlier studies in the rat that have suggested the presence of a combinatorial map