1,783 research outputs found

    KINEMATICAL ANALYSIS OF 110M HURDLES - FOCUSING ON THE STEP LENGTH

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    The adaptations to each of the four steps are required for good performance in 110m hurdles (McDonald, 2002). However, the motions related with both running velocity and step length are not studied yet. Thus the purpose of this study was to investigate kinematic characteristics of 110m hurdlers with reference to step length

    Building Foundation Instability Induced by Tsunami Scour

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    Understanding the role of tsunami-induced scour in building foundation instability can allow for the proper design of buildings located in areas prone to tsunami events. The process of tsunami scour around building foundations reduces the bearing capacity of the soil to support loading, lateral resistance and loss of soil- foundation friction (i.e. piles). Scour can cause loss of material around a foundation, due to increased pore pressure within the soil and removal of the soil during the tsunami, resulting in reduced bearing capacity of the soil (Macabuag et al., 2018). During the 2004 Indian Ocean Tsunami and the 2011 Great East Japan Earthquake and Tsunami, three similar failure modes of building foundations were experienced, namely overturning, sliding and bearing (scour) failure (Macabuag et al., 2018). According to Wright (2015), shallow foundations such as strip, slab or pad are vulnerable to erosion of surrounding soil causing scour during a tsunami. The present paper discusses the application of the scour depth predictive model of Nicholas et al. (2016) and the development of a Relative Risk Index for future design of building foundations accounting for tsunamis

    Modelling of Krakatoa Tsunami Wave Propagation and Community Engagement Based on SWOT Analysis in Southern Lampung, Indonesia

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    The eruption of Krakatoa which occurred on the 22 December 2018 caused an avalanche from the Gunung Anak Krakatau (GAK) body into the sea, causing a tsunami in the Sunda Strait. The tsunami affected Lampung (Sumatra) and Banten (Java) provinces in Indonesia. Based on the field observations made by Takabatake et al. (2019) in the southern part of Lampung, it was identified that there were severely damaged areas in Lampung; i.e. East Way Muli, Central Way Muli, and Kunjir villages. A numerical model was developed to simulate past and future tsunami wave propagation scenarios. In addition, the strategic planning technique of SWOT analysis was carried out in order to make recommendations for the resilience of local coastal communities for future tsunami events in Southern Lampung

    EFFECTS OF FATIGUE ON THE GROUND REACTION FORCES AND LEG KINEMATICS IN ALL-OUT 600 METERS RUNNING

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    The purpose of this study was to investigate effects of fatigue on the ground reaction forces and leg kinematics during all-out 600m running, which was performed by eight male middle-distance runners. Their running motion was videotaped (300Hz) and the ground reaction forces were measured (500Hz) at the 150m and 550m marks of the 600m running. From the 150m to 550m mark, running speed significantly decreased (

    Quantum dislocations: the fate of multiple vacancies in two dimensional solid 4He

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    Defects are believed to play a fundamental role in the supersolid state of 4He. We have studied solid 4He in two dimensions (2D) as function of the number of vacancies n_v, up to 30, inserted in the initial configuration at rho = 0.0765 A^-2, close to the melting density, with the exact zero temperature Shadow Path Integral Ground State method. The crystalline order is found to be stable also in presence of many vacancies and we observe two completely different regimes. For small n_v, up to about 6, vacancies form a bound state and cause a decrease of the crystalline order. At larger n_v, the formation energy of an extra vacancy at fixed density decreases by one order of magnitude to about 0.6 K. In the equilibrated state it is no more possible to recognize vacancies because they mainly transform into quantum dislocations and crystalline order is found almost independent on how many vacancies have been inserted in the initial configuration. The one--body density matrix in this latter regime shows a non decaying large distance tail: dislocations, that in 2D are point defects, turn out to be mobile, their number is fluctuating, and they are able to induce exchanges of particles across the system mainly triggered by the dislocation cores. These results indicate that the notion of incommensurate versus commensurate state loses meaning for solid 4He in 2D, because the number of lattice sites becomes ill defined when the system is not commensurate. Crystalline order is found to be stable also in 3D in presence of up to 100 vacancies

    Electronic Properties of Topological Materials: Optical Excitations in Moebius Conjugated Polymers

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    Electronic structures and optical excitations in Moebius conjugated polymers are studied theoretically. Periodic and Moebius boundary conditions are applied to the tight binding model of poly(para-phenylene), taking exciton effects into account. We discuss that oligomers with a few structural units are more effective than polymers for observations of effects of discrete wave numbers that are shifted by the change in boundary condition. Next, calculations of optical absorption spectra are reported. Certain components of optical absorption for an electric field perpendicular to the polymer axis mix with absorption spectra for an electric field parallel to the polymer axis. Therefore, the polarization dependences of an electric field of light enable us to detect whether conjugated polymers have the Moebius boundary.Comment: 10 pages, 6 figures, to be published in J. Phys. Soc. Jpn., Vol. 74 No. 2 (February, 2005), Letter sectio

    On the existence of supersolid helium-4 monolayer films

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    Extensive Monte Carlo simulations of helium-4 monolayer films adsorbed on weak substrates have been carried out, aimed at ascertaining the possible occurrence of a quasi-two-dimensional supersolid phase. Only crystalline films not registered with underlying substrates are considered. Numerical results yield strong evidence that helium-4 will not form a supersolid film on {any} substrate strong enough to stabilize a crystalline layer. On weaker substrates, continuous growth of a liquid film takes place

    A General Equilibrium Model of Environmental Option Values

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    In this paper we consider the option value of the environment employing a stochastic general equilibrium growth model. In our model, as in existing studies, because of irreversibility, the environment has significant real option value. However, unlike the existing literature, the value of the environment is endogenously determined in our general equilibrium setting. In our model, the elasticity of substitution between the environment and consumption not only has quantitative effects but also qualitative effects on the option value of the environment and the optimal allocation of land. We also show that the volatility of the exogenous shock process has quantitatively significant effects on the size of the option value which has important implications for the practical estimation of environmental option values

    High-pressure phase diagram of NdFeAsO0.9F0.1: Disappearance of superconductivity on the verge of ferromagnetism from Nd moments

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    We investigated transport and magnetic properties of single crystal NdFeAsO0.9F0.1 under hydrostatic pressures up to 50 GPa. The ambient pressure superconductivity at Tc ∼ 45.4 K was fully suppressed at Pc ∼ 21 GPa. Upon a further increase of pressure, ferromagnetism associated with the order of the rare-earth subsystem was induced at the border of superconductivity. Our finding is supported by the hysteresis in the magnetization M(H) loops and the strong increase in the field cooled data M(T ) toward low temperatures. We also show that the temperature evolution of the electrical resistivity as a function of pressure is consistent with a crossover from a Fermi liquid to non-Fermi liquid to Fermi liquid. The Hall measurements suggest that the multiband electronic structures have changed with pressure, which should also affect the resistivity behavior. These results give access to the high-pressure side of the superconducting phase diagram in the 1111 type of materials
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