5,120 research outputs found

    An evaluation of the one percent clustered sample of the 1990 Census of China

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    We describe and evaluate a one percent clustered sample of the 1990 Census of China, the largest publicly-available micro sample of any Chinese census, using direct inspection as well as comparisons with published data drawn from the complete enumeration. In the absence of official documentation, we elucidate the basis of the clustering; detect duplicate cases; report corrected totals; and make comparisons between the sample data and tabulations based on the complete enumeration at the province and county levels. Although the sample contains several anomalies, we conclude that it is broadly serviceable.1990 Census, China, evaluation, sample data

    Hi-alpha forebody design. Part 1: Methodology base and initial parametrics

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    The use of Computational Fluid Dynamics (CFD) has been investigated for the analysis and design of aircraft forebodies at high angle of attack combined with sideslip. The results of the investigation show that CFD has reached a level of development where computational methods can be used for high angle of attack aerodynamic design. The classic wind tunnel experiment for the F-5A forebody directional stability has been reproduced computationally over an angle of attack range from 10 degrees to 45 degrees, and good agreement with experimental data was obtained. Computations have also been made at combined angle of attack and sideslip over a chine forebody, demonstrating the qualitative features of the flow, although not producing good agreement with measured experimental pressure distributions. The computations were performed using the code known as cfl3D for both the Euler equations and the Reynolds equations using a form of the Baldwin-Lomax turbulence model. To study the relation between forebody shape and directional stability characteristics, a generic parametric forebody model has been defined which provides a simple analytic math model with flexibility to capture the key shape characteristics of the entire range of forebodies of interest, including chines

    Hi-alpha forebody design. Part 2: Determination of body shapes for positive directional stability

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    Computational Fluid Dynamics (CFD) has been used to study aircraft forebody flowfields at low speed high angle-of-attack conditions with sideslip. The purpose is to define forebody geometries which provide good directional stability characteristics under these conditions. The flows of the F-5A forebody and Erickson forebody were recomputed with better and refined grids. The results were obtained using a modified version of cfl3d to solve either the Euler equations or the Reynolds equations employing a form of the Baldwin-Lomax turbulence model. Based on those results, we conclude that current CFD methods can be used to investigate the aerodynamic characteristics of forebodies to achieve desirable high angle-of-attack characteristics. An analytically defined generic forebody model is described, and a systematic study of forebody shapes was then conducted to determine which shapes promote a positive contribution to directional stability at high angle-of-attack. A novel way of presenting the results is used to illustrate how the positive contribution arises. Based on the results of this initial parametric study, some guidelines for aerodynamic design to promote positive directional stability are presented

    A computational examination of directional stability for smooth and chined forebodies at high-alpha

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    Computational Fluid Dynamics (CFD) has been used to study aircraft forebody flowfields at low-speed, angle-of-attack conditions with sideslip. The purpose is to define forebody geometries which provide good directional stability characteristics under these conditions. The flows over the experimentally investigated F-5A forebody and chine type configuration, previously computed by the authors, were recomputed with better grid topology and resolution. The results were obtained using a modified version of CFL3D (developed at NASA Langley) to solve either the Euler equations or the Reynolds equations employing the Baldwin-Lomax turbulence model with the Degani-Schiff modification to account for massive crossflow separation. Based on the results, it is concluded that current CFD methods can be used to investigate the aerodynamic characteristics of forebodies to achieve desirable high angle-of-attack characteristics. An analytically defined generic forebody model is described, and a parametric study of various forebody shapes was then conducted to determine which shapes promote a positive contribution to directional stability at high angle-of-attack. An unconventional approach for presenting the results is used to illustrate how the positive contribution arises. Based on the results of this initial parametric study, some guidelines for aerodynamic design to promote positive directional stability are presented

    Speckle interferometry at the Blanco and SOAR telescopes in 2008 and 2009

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    The results of speckle interferometric measurements of binary and multiple stars conducted in 2008 and 2009 at the Blanco and SOAR 4-m telescopes in Chile are presented. A total of 1898 measurements of 1189 resolved pairs or sub-systems and 394 observations of 285 un-resolved targets are listed. We resolved for the first time 48 new pairs, 21 of which are new sub-systems in close visual multiple stars. Typical internal measurement precision is 0.3 mas in both coordinates, typical companion detection capability is Ī”māˆ¼4.2\Delta m \sim 4.2 at 0\farcs15 separation. These data were obtained with a new electron-multiplication CCD camera; data processing is described in detail, including estimation of magnitude difference, observational errors, detection limits, and analysis of artifacts. We comment on some newly discovered pairs and objects of special interest.Comment: Accepted for publication in Astronomical Journal. Tables 4,5,7 will be published electronically, they are available in full from the author

    The Politics of Nostalgia and Its Discontents: An Intensive Case Study of the Tea Party Social Movement in the United States of America

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    The focus of the thesis is an intensive case study of the processes accompanying the mobilisation and growth of the social movement known as the Tea Party in the United States of America. The thesis is grounded in an analytical lens of issue framing, which has come to be regarded as an equally-important framework in understanding the dynamics of social movements (Benford and Snow 2000: 612) alongside the more traditional lenses of resource mobilisation theory and political opportunity structure. The thesis combines a cultural approach to the social movement with the political sociology of emotion by examining the emotional implications of cultural foci like historical narratives, figurative rhetoric and archaic artifacts, which have been utilised by the Tea Party in its protest performances. The thesis finds that by appropriating the cultural history of the United States in its resonant collective action frames, the Tea Party has consciously and rationally exacerbated the emotions of distrust of the government, outrage towards existing policies but hope for the future amongst its activist bases in order to mobilise and grow in support
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