2,348 research outputs found

    Cartographic research in EREP program for small scale mapping

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    The author has identified the following significant results. Skylab photography is suitable for producing planimetric maps with graphical representation of landform at scales up to 1:100,000. It cannot supply all the detail necessary for maps at this scale, but it may be used to produce a sound framework which can be completed by detail from other sources. Its principal cartographic use is for original mapping of undeveloped areas of the world, but it would also be useful for the revision of existing maps and for monitoring extensive urban changes

    On composite laminates with extensional anisotropy

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    The definite list of extensionally (membrane) anisotropic composite laminates with up to 21 plies is presented. The listings comprise of individual stacking sequences, which are characterized in terms of angle- and cross-ply sub-sequence relationships as well as the blend-ratio of unbalanced angle-plies. Dimensionless parameters, including lamination parameters, are provided, from which the extensional and bending stiffness terms are readily calculated and an assessment of the bending stiffness efficiency made for angle- and cross-ply sub-sequences. Comparisons are made between the structural response of extensionally-anisotropic laminates and laminates with both extensional- and bending-anisotropy; Initial- and post-buckling responses are considered at the panel level together with the static response of a complete wing-box structure

    Characterization of ply mixing rules for non-symmetric forms of fully orthotropic laminates

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    Stacking sequence listings are presented for fully orthotropic angle-ply laminates, with up to 21 plies, together with rules for mixing these sequences to form laminates containing any number of plies. The mixing rules are demonstrated through an abridged set of sequences, which are characterized in terms of angle- and cross-ply sub-sequence symmetries. The abridged set of sequences is derived from a new definitive list that supersedes previously published listings. Stacking sequences are presented together with dimensionless parameters from which the bending stiffness terms are readily calculated and an assessment of the bending stiffness efficiency made for angle- and cross-ply sub-sequences. Expressions relating the dimensionless parameters to the well-known lamination parameters are also given, together with graphical representations of feasible domains for all sub-sequence symmetries contained in the definitive list. Feasible domains for extensionally isotropic and fully isotropic laminates are also presented as important sub-sets of fully orthotropic laminates. Finally, examples are given for tapered laminates with fully orthotropic properties, derived from compatible sequences in the definite list

    Stacking sequences for extensionally isotropic, fully isotropic and quasi-homogeneous orthotropic laminates

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    Stacking sequence listings are presented for fully uncoupled Extensionally Isotropic (EILs), Fully Isotropic (FILs) and Quasi-Homogeneous Orthotropic (QHOLs) angle-ply Laminates, with up to 21 plies. All are sub-sets of a definitive list of Fully Orthotropic Laminates (FOLs), containing generally non-symmetric stacking sequences that are characterized in terms of angle- and cross-ply sub-sequence symmetries. Dimensionless parameters are given for each stacking sequence, from which the ABD matrix is readily derived. Expressions relating these dimensionless parameters to the well-known lamination parameters are also given, together with graphical representations of the feasible domains for Pi/3 and Pi/4 EILs and angle-ply QHOLs containing two and three ply orientations. The feasible domain for Pi/3 FILs is represented graphically by a single point, whereas the domain for angle-ply QHOLs containing four ply orientations is represented by a single stacking sequence

    Critical fluctuations in superconductors and the magnetic field penetration depth

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    The superconducting transition is studied within the one-loop renormalization group in fixed dimension D=3D=3 and at the critical point. A tricritical behavior is found, and for ΞΊ>ΞΊc\kappa > \kappa_c, an attractive charged fixed point, distinct from that of a neutral superfluid. The critical exponents of the continuous transition are evaluated, and it is shown that the anomalous dimension of the gauge field equals unity. This implies the proportionality of the magnetic field penetration depth and the superconducting correlation length below the transition. The penetration depth exponent is nonclassical. We argue that it can not be extracted from the dual theory in a straightforward manner since it is not renormalized by fluctuations of the dual field.Comment: 12 pages, LaTex, two figures available upon reques

    Critical Phenomena with Linked Cluster Expansions in a Finite Volume

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    Linked cluster expansions are generalized from an infinite to a finite volume. They are performed to 20th order in the expansion parameter to approach the critical region from the symmetric phase. A new criterion is proposed to distinguish 1st from 2nd order transitions within a finite size scaling analysis. The criterion applies also to other methods for investigating the phase structure such as Monte Carlo simulations. Our computational tools are illustrated at the example of scalar O(N) models with four and six-point couplings for N=1N=1 and N=4N=4 in three dimensions. It is shown how to localize the tricritical line in these models. We indicate some further applications of our methods to the electroweak transition as well as to models for superconductivity.Comment: 36 pages, latex2e, 7 eps figures included, uuencoded, gzipped and tarred tex file hdth9607.te

    The development and validation of the Interpersonal Support in Physical Activity Consultations Observational Tool

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    This study describes the development and psychometric characteristics of an observational instrument that examines four aspects of interpersonal support (or lack of) provided during physical activity (PA) promotion consultations (i.e., Autonomy Support, Involvement, Structure and Interpersonal Control), as identified by Self-determination Theory (SDT). The reliability and validity of the Interpersonal Support in Physical Activity Consultations Observational Tool (ISPACOT) were examined within an exploratory randomised control trial. Recorded consultations (N = 42) conducted by qualified PA advisors (N = 14) at 13 leisure centres across the West Midlands (UK) were rated. Intra-class correlation coefficients (ICC) indicated moderate to high inter-rater reliability for overall interpersonal support (0.80), and the Autonomy Support (0.74), Involvement (0.73) and Structure (0.91) dimensions, but low reliability for Interpersonal Control (0.35). The advisors, who conducted PA promotion consultations that were rated as low in their interpersonally supportive features, were perceived by their clients as being less supportive (F(1,10) = 5.0, p <.05). Ratings on the ISPACOT differentiated advisors who were trained in SDT principles and those who were not. Overall, the findings provided preliminary evidence for the reliability and convergent validity of the ISPACOT

    Factor copula models for item response data

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    Factor or conditional independence models based on copulas are proposed for multivariate discrete data such as item responses. The factor copula models have interpretations of latent maxima/minima (in comparison with latent means) and can lead to more probability in the joint upper or lower tail compared with factor models based on the discretized multivariate normal distribution (or multidimensional normal ogive model). Details on maximum likelihood estimation of parameters for the factor copula model are given, as well as analysis of the behavior of the log-likelihood. Our general methodology is illustrated with several item response data sets, and it is shown that there is a substantial improvement on existing models both conceptually and in fit to data
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