16,843 research outputs found

    The synthesis of 15 mu infrared horizon radiance profiles from meteorological data inputs

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    Computational computer program for modeling infrared horizon radiance profile using pressure and temperature profile input

    COMPARISON OF RIGHT VS. LEFT LEG GRF LANDING SYMMETRY FOR HEALTHY AND OVERUSE INJURY-PRONE RECREATIONAL ATHLETES

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    PURPOSE AND METHODS The purpose of the study was to compare right versus left leg symmetry during landing for healthy (n = 10) and overuse injury-prone (n = 10) recreational athletes. Landing symmetry was evaluated by examining vertical ground reaction force (GRF; 1000 Hz) magnitude and temporal variables for each leg and subject group while landing from three different heights (50, 100, and 200% of maximum vertical jump, MVJ). Magnitudes of the first (Fl) and second (F2) maximum force values were identified along with the temporal occurrences of these events (T1 and T2, respectively). Vertical GRF pattern consistency varied among subjects and across heights, therefore, when Fl and F2 could not be individually identified the maximum force magnitude and temporal values for the landing phase were assigned to the F2 and T2 variables, respectively. The F2 and T2 values were utilized to evaluate differences between legs (one-way Analysis of Variance, ANOVA; = 0.05) for each group and landing height. Additionally, GRF pattern consistency between right and left legs (for both subject groups) was monitored by a tally which tracked the number of unimodal (single peak) curves for each landing height. RESULTS Results of the ANOVA procedures indicated no significant differences (p > 0.05) between the right and left side GRF magnitude or temporal variables for the healthy subject group. The injury prone group exhibited significant right-left side differences for the 50% MVJ height (p < 0.01; right greater than left) and for the 100% MVJ height condition (p < 0.05; right greater than left). No right-left temporal differences were observed for the injury prone group. Results of the descriptive GRF tally for the occurrence of unimodal landing curve patterns suggest that the injury prone group might have been more consistent between legs in producing traditional bimodal GRF-time histories. A unimodal curve was defined as a GRF-time history that did not follow the typical bimodal (Fl-toe, F2-heel) landing pattern. The 50% MVJ height elicited a right-left unimodal curve count of 21 and 30, respectively, for the healthy group and 19 and 19, respectively, for the injury prone subjects. For the 100% MVJ height condition the healthy group exhibited a total (sum of all subjects) of two right side and three left side unimodal curves, while the injury prone group exhibited no unimodal curves from either leg. No unimodal curves were detected for either subject group while landing from the 200% MVJ height. CONCLUSIONS The functional significance of these results is not clear. However, one might speculate that the asymmetrical GRF magnitude values observed for the injury prone group are related to their injury history, although the causeeffect relationship cannot be determined from these data. The number of differences between right and left leg unimodal curves might be related to the amount of movement variability exhibited by each subject group. The fewer total number of unimodal curves and the fewer number of right-left differences suggest less performance variability for theinjury prone group

    Multi-objective evolutionary–fuzzy augmented flight control for an F16 aircraft

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    In this article, the multi-objective design of a fuzzy logic augmented flight controller for a high performance fighter jet (the Lockheed-Martin F16) is described. A fuzzy logic controller is designed and its membership functions tuned by genetic algorithms in order to design a roll, pitch, and yaw flight controller with enhanced manoeuverability which still retains safety critical operation when combined with a standard inner-loop stabilizing controller. The controller is assessed in terms of pilot effort and thus reduction of pilot fatigue. The controller is incorporated into a six degree of freedom motion base real-time flight simulator, and flight tested by a qualified pilot instructor

    Geometry and topology of knotted ring polymers in an array of obstacles

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    We study knotted polymers in equilibrium with an array of obstacles which models confinement in a gel or immersion in a melt. We find a crossover in both the geometrical and the topological behavior of the polymer. When the polymers' radius of gyration, RGR_G, and that of the region containing the knot, RG,kR_{G,k}, are small compared to the distance b between the obstacles, the knot is weakly localised and RGR_G scales as in a good solvent with an amplitude that depends on knot type. In an intermediate regime where RG>b>RG,kR_G > b > R_{G,k}, the geometry of the polymer becomes branched. When RG,kR_{G,k} exceeds b, the knot delocalises and becomes also branched. In this regime, RGR_G is independent of knot type. We discuss the implications of this behavior for gel electrophoresis experiments on knotted DNA in weak fields.Comment: 4 pages, 6 figure

    Exploring the psychosocial and behavioural determinants of household water conservation and intention

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    Securing urban freshwater supplies is a major challenge for policy makers globally. This study investigated the determinants of household water conservation to identify the relative contribution of psychosocial and behavioural determinants. Using a survey of 1196 households across the UK, we found that attitudes, norms and habits play an important role in determining intention to conserve water, and that habits were the single most important predictor of water conservation intentions and self-reported water bills. Changing ingrained water conservation habits is therefore an important component of managing urban water demand

    Instabilities and disorder of the domain patterns in the systems with competing interactions

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    The dynamics of the domains is studied in a two-dimensional model of the microphase separation of diblock copolymers in the vicinity of the transition. A criterion for the validity of the mean field theory is derived. It is shown that at certain temperatures the ordered hexagonal pattern becomes unstable with respect to the two types of instabilities: the radially-nonsymmetric distortions of the domains and the repumping of the order parameter between the neighbors. Both these instabilities may lead to the transformation of the regular hexagonal pattern into a disordered pattern.Comment: ReVTeX, 4 pages, 3 figures (postscript); submitted to Phys. Rev. Let
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