31,262 research outputs found

    Parameter identification for a robotic manipulator arm

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    The development is described of a nonlinear dynamic model for large oscillations of a robotic manipulator arm about a single joint. Optimization routines are formulated and implemented for the identification of electrical and physical parameters from dynamic data taken from an industrial robot arm. Special attention is given to the role of sensitivity in the formulation of robust models of this motion. The importance of actuator effects in the reduction of sensitivity is established and used to develop an electromechanical model of the manipulator system

    Parameter identification and sensitivity analysis for a robotic manipulator arm

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    The development of a nonlinear dynamic model for large oscillations of a robotic manipulator arm about a single joint is described. Optimization routines are formulated and implemented for the identification of electrical and physical parameters from dynamic data taken from an industrial robot arm. Special attention is given to difficulties caused by the large sensitivity of the model with respect to unknown parameters. Performance of the parameter identification algorithm is improved by choosing a control input that allows actuator emf to be included in an electro-mechanical model of the manipulator system

    Free-flight measurements of dynamic stability derivatives of a blunted 120 deg cone in helium at Mach number 15.4

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    Free flight measurements of dynamic stability derivatives of blunted 120 deg cone in helium compared to unmodified Newtonian theory prediction

    International consensus (ICON) on treatment of Ménière's disease

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    Objective: To present the international consensus for recommendations for Ménière's disease (MD) treatment. Methods: Based on a literature review and report of 4 experts from 4 continents, the recommendations have been presented during the 21st IFOS congress in Paris, in June 2017 and are presented in this work. Results: The recommendation is to change the lifestyle, to use the vestibular rehabilitation in the intercritic period and to propose psychotherapy. As a conservative medical treatment of first line, the authors recommend to use diuretics and Betahistine or local pressure therapy. When medical treatment fails, the recommendation is to use a second line treatment, which consists in the intratympanic injection of steroids. Then as a third line treatment, depending on the hearing function, could be either the endolymphatic sac surgery (when hearing is worth being preserved) or the intratympanic injection of gentamicin (with higher risks of hearing loss). The very last option is the destructive surgical treatment labyrinthectomy, associated or not to cochlear implantation or vestibular nerve section (when hearing is worth being preserved), which is the most frequent option

    Do physiotherapists have the skill to engage in the psychological in the bio-psychosocial approach?

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    Purpose: To describe a cross-sectional exploration of attitudes of physiotherapists in general practice in Western Australia toward psychiatry and mental illness, how often they treat people with mental illness, their perceptions of how well their undergraduate education prepared them to work with these people, and their opinions about what further education would enable them to provide best practice care. Methods: A questionnaire that included questions about participants’ demographic information, personal experiences with mental illness, the ATP-30, and open-ended questions about their preparedness to work with people with mental illness was distributed through 110 email contacts to physiotherapy departments in Western Australia. Results: A total of 75 completed questionnaires contributed to the findings; 11 returned questionnaires were incomplete and were not included in the data analysis. ATP-30 scores indicated moderately positive attitudes toward psychiatry and mental illness. Females indicated significantly more positive attitudes than males. Of the full sample, 41% (n = 31) reported treating someone with a comorbid mental health problem every day and 76% (n = 57) every week. Conclusion: Physiotherapists in general practice in Western Australia have generally positive perceptions of psychiatry. The majority of clinicians reported treating patients with mental illness at least once a week. Participants identified that they felt underprepared to work with this patient group, a need for the undergraduate curriculum to be revised, and an overwhelming need for postgraduate training in psychiatry and mental health

    Time resolved spectroscopy of dust and gas from extrasolar planetesimals orbiting WD 1145+017

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    Multiple long and variable transits caused by dust from possibly disintegrating asteroids were detected in light curves of WD 1145+017. We present time-resolved spectroscopic observations of this target with QUCAM CCDs mounted in the Intermediate dispersion Spectrograph and Imaging System at the 4.2-m William Herschel Telescope in two different spectral arms: the blue arm covering 3800-4025 {\AA} and the red arm covering 7000-7430 {\AA}. When comparing individual transits in both arms, our observations show with 20 {\sigma} significance an evident colour difference between the in- and out-of-transit data of the order of 0.05-0.1 mag, where transits are deeper in the red arm. We also show with > 6 {\sigma} significance that spectral lines in the blue arm are shallower during transits than out-of-transit. For the circumstellar lines it also appears that during transits the reduction in absorption is larger on the red side of the spectral profiles. Our results confirm previous findings showing the u'-band excess and a decrease in line absorption during transits. Both can be explained by an opaque body blocking a fraction of the gas disc causing the absorption, implying that the absorbing gas is between the white dwarf and the transiting objects. Our results also demonstrate the capability of EMCCDs to perform high-quality time resolved spectroscopy of relatively faint targets.Comment: 9 pages, 5 figures. Accepted to MNRA

    A ground-based NUV secondary eclipse observation of KELT-9b

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    KELT-9b is a recently discovered exoplanet with a 1.49 d orbit around a B9.5/A0-type star. The unparalleled levels of UV irradiation it receives from its host star put KELT-9b in its own unique class of ultra-hot Jupiters, with an equilibrium temperature > 4000 K. The high quantities of dissociated hydrogen and atomic metals present in the dayside atmosphere of KELT-9b bear more resemblance to a K-type star than a gas giant. We present a single observation of KELT-9b during its secondary eclipse, taken with the Wide Field Camera on the Isaac Newton Telescope (INT). This observation was taken in the U-band, a window particularly sensitive to Rayleigh scattering. We do not detect a secondary eclipse signal, but our 3σ\sigma upper limit of 181 ppm on the depth allows us to constrain the dayside temperature of KELT-9b at pressures of ~30 mbar to 4995 K (3σ\sigma). Although we can place an observational constraint of Ag<A_g< 0.14, our models suggest that the actual value is considerably lower than this due to H−^- opacity. This places KELT-9b squarely in the albedo regime populated by its cooler cousins, almost all of which reflect very small components of the light incident on their daysides. This work demonstrates the ability of ground-based 2m-class telescopes like the INT to perform secondary eclipse studies in the NUV, which have previously only been conducted from space-based facilities.Comment: Accepted in ApJL. 7 pages, 3 figure

    Structural and Electronic Properties of Amorphous and Polycrystalline In2Se3 Films

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    Structural and electronic properties of amorphous and single-phase polycrystalline films of gamma- and kappa-In2Se3 have been measured. The stable gamma phase nucleates homogeneously in the film bulk and has a high resistivity, while the metastable kappa phase nucleates at the film surface and has a moderate resistivity. The microstructures of hot-deposited and post-annealed cold-deposited gamma films are quite different but the electronic properties are similar. The increase in the resistivity of amorphous In2Se3 films upon annealing is interpreted in terms of the replacement of In-In bonds with In-Se bonds during crystallization. Great care must be taken in the preparation of In2Se3 films for electrical measurements as the presence of excess chalcogen or surface oxidation may greatly affect the film properties.Comment: 23 pages and 12 figure
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