18,894 research outputs found

    A human body model for dynamic response analysis of an integrated human-seat-controller-high speed marine craft interaction system

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    Small boats are increasingly being operated at high speed in rough weather by organisations carrying out essential missions such as the military and rescue services. Crew and passengers on these boats are exposed to continuous vibration and impacts leading to reduced crew effectiveness, fatigue and the possibility of injury. In addition to this marine craft will soon fall under the jurisdiction of the European Union Directive 2002/44/EC on the protection of workers from vibration.To assess the possibility of injury and mitigate it at the design stage of a vessel a design tool is needed to assess the vibration levels on/in the human body while the boat operates in dynamic environments. A review of current human body models is presented and a new human body model, which allows for estimates of muscle activity, is proposed. This model is supplemented by a numerical approach using finite element methods to assess the dynamic response of the integrated human-seat-controller-boat interaction system excited by wave loads or boat motions measured in full scale boat operation tests. The vibration control actuators are arranged between the seat and boat to reduce vibrations transmitted to the human body from the boat to obtain a comfortable ride condition

    A human body model for dynamic response analysis of an integrated human-seat-controller-high speed marine craft interaction system

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    Small boats are increasingly being operated at high speed in rough weather by organisations carrying out essential missions such as the military and rescue services. Crew and passengers on these boats are exposed to continuous vibration and impacts leading to reduced crew effectiveness, fatigue and the possibility of injury. In addition to this marine craft will soon fall under the jurisdiction of the European Union Directive 2002/44/EC on the protection of workers from vibration.To assess the possibility of injury and mitigate it at the design stage of a vessel a design tool is needed to assess the vibration levels on/in the human body while the boat operates in dynamic environments. A review of current human body models is presented and a new human body model, which allows for estimates of muscle activity, is proposed. This model is supplemented by a numerical approach using finite element methods to assess the dynamic response of the integrated human-seat-controller-boat interaction system excited by wave loads or boat motions measured in full scale boat operation tests. The vibration control actuators are arranged between the seat and boat to reduce vibrations transmitted to the human body from the boat to obtain a comfortable ride condition

    The effect of China's one-child family policy after 25 years

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    Complementary and Alternative Medicine (CAM) Therapies in the Treatment of Meniere's Syndrome: Illness Narratives

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    Colonnade interior, glass wall, from above, depicting brise-soleil; The building today commonly referred to as the Old City Hall was the building that served as Ottawa's city hall from 1958 to 2000. Today it is officially known as 111 Sussex Drive and is owned by the Federal Government of Canada. The building is located on Green Island at the point where the Rideau River empties into the Ottawa. The International Style building was opened on August 2, 1958 by Princess Margaret as a member of the Canadian Royal Family. It is noted for the first building in Ottawa to be fully air conditioned. It was designed by John Bland of the firm of Rother, Bland and Trudeau and is considered one of the most important International Style buildings in Canada. Winning the Massey Medal for design in 1959, modifications were made by Moshe Safdie in 1992-1993. Today the building mainly houses foreign affairs employees. Source: Wikipedia; http://en.wikipedia.org/wiki/Main_Page (accessed 1/10/2008

    The T2K Indication of Relatively Large theta_13 and a Natural Perturbation to the Democratic Neutrino Mixing Pattern

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    The T2K Collaboration has recently reported a remarkable indication of the \nu_\mu -> \nu_e oscillation which is consistent with a relatively large value of \theta_{13} in the three-flavor neutrino mixing scheme. We show that it is possible to account for such a result of \theta_{13} by introducing a natural perturbation to the democratic neutrino mixing pattern, without or with CP violation. A testable correlation between \theta_{13} and \theta_{23} is predicted in this ansatz. We also discuss the Wolfenstein-like parametrization of neutrino mixing, and comment on other possibilities of generating sufficiently large \theta_{13} at the electroweak scale.Comment: RevTeX 8 page

    Water production rates and activity of interstellar comet 2I/Borisov

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    We observed the interstellar comet 2I/Borisov using the Neil Gehrels-Swift Observatory's Ultraviolet/Optical Telescope. We obtained images of the OH gas and dust surrounding the nucleus at six epochs spaced before and after perihelion (-2.56 AU to 2.54 AU). Water production rates increased steadily before perihelion from (7.0±1.5)×1026(7.0\pm1.5)\times10^{26} molecules s1^{-1} on Nov. 1, 2019 to (10.7±1.2)×1026(10.7\pm1.2)\times10^{26} molecules s1^{-1} on Dec. 1. This rate of increase in water production rate is quicker than that of most dynamically new comets and at the slower end of the wide range of Jupiter-family comets. After perihelion, the water production rate decreased to (4.9±0.9)×1026(4.9\pm0.9)\times10^{26} molecules s1^{-1} on Dec. 21, which is much more rapidly than that of all previously observed comets. Our sublimation model constrains the minimum radius of the nucleus to 0.37 km, and indicates an active fraction of at least 55% of the surface. A(0)fρA(0)f\rho calculations show a variation between 57.5 and 105.6 cm with a slight trend peaking before the perihelion, lower than previous and concurrent published values. The observations confirm that 2I/Borisov is carbon-chain depleted and enriched in NH2_2 relative to water.Comment: 12 pages, 3 figures, 2 tables, submitted to ApJ

    Controlled switching between paramagnetic and diamagnetic Meissner effect in Pb/Co nanocomposites

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    A hybrid system which consists of a superconducting (SC) Pb film (100 nm thickness) containing \sim1 vol% single domain ferromagnetic (FM) Co particles of mean-size \sim4.5 nm reveal unusual magnetic properties: (i) a controlled switching between the usual diamagnetic and the unusual paramagnetic Meissner effect in field cooling as well as in zero-field cooling experiments (ii) amplification of the positive magnetization when the sample enters the SC state below Tc_c. These experimental findings can be explained by the formation of spontaneous vortices and the possible alignment of these vortices due to the foregoing alignment of the Co particle FM moments by an external magnetic field.Comment: 5 pages, 3 figure

    Updated Values of Running Quark and Lepton Masses

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    Reliable values of quark and lepton masses are important for model building at a fundamental energy scale, such as the Fermi scale M_Z \approx 91.2 GeV and the would-be GUT scale \Lambda_GUT \sim 2 \times 10^16 GeV. Using the latest data given by the Particle Data Group, we update the running quark and charged-lepton masses at a number of interesting energy scales below and above M_Z. In particular, we take into account the possible new physics scale (\mu \sim 1 TeV) to be explored by the LHC and the typical seesaw scales (\mu \sim 10^9 GeV and \mu \sim 10^12 GeV) which might be relevant to the generation of neutrino masses. For illustration, the running masses of three light Majorana neutrinos are also calculated. Our up-to-date table of running fermion masses are expected to be very useful for the study of flavor dynamics at various energy scales.Comment: 23 pages, 6 tables, 2 figures; version published in PR
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