Procedia IUTAM最新文献

In the current review, the most pessimistic events of the globe in history are addressed when we present severe impacts caused by storm surges. During previous decades, great progresses in storm surge modeling have been made. As a result, people have developed a number of numerical software such as SPLASH, SLOSH etc. and implemented routine operational forecast by virtue of powerful supercomputers with the help of meteorological satellites and sensors as verification tools. However, storm surge as a killer from the sea is still threatening human being and exerting enormous impacts on human society due to economic growth, population increase and fast urbanization. To mitigate the effects of storm surge hazards, integrated research on disaster risk (IRDR) as an ICSU program is put on agenda. The most challenging issues concerned such as abrupt variation in TC’s track and intensity, comprehensive study on the consequences of storm surge and the effects of climate change on risk estimation are emphasized. In addition, it is of paramount importance for coastal developing countries to set up forecast and warning system and reduce vulnerability of affected areas.

The storm surge and inundation simulation using the shallow-water circulation model ADCIRC has been implemented for the Cangnan County of Zhejiang Province. The main purpose is using this model to estimate the coastal storm surge disaster risk and zoning. The hindcast experiments indicate that the model system has good performance in capturing the changes of storm surge caused by tropical cyclones. Compared to the observations, the average deviation of the peak value of water level is less than 10%. We used the hypothetical tropical cyclones and the 19a of June-October mean high astronomical tide, and combined the geographic elevation and land description to assess the inundation hazard. It shows that the inundation hazard is high in the coastal region of Jinxiang Town and the south bank area of Aojiang River, but is relatively low in the Jiangnan Inning and the high altitude inland areas. The risk assessment that integrates the inundation hazard and the structure vulnerability is also conducted to zone the county into the different storm surge disaster risk levels, which can give support to the effective prevention of various tropical cyclone storm surge in the future.

Storm surge is an important issue in Taiwan because our country is located at the typhoon prone area and surrounded by the Pacific Ocean and the Taiwan Strait. People live at coastal areas need to pay attention to the damages of storm surge, especially the inundation during typhoon’s duration. Therefore, the accurate and highly efficient operational storm surge system is required to provide not only the information of water elevations but also potential inundation areas. The large computational domain should be adopted to cover the complete typhoon life-cycle, and the atmospheric model and tidal model are expected to be coupled inside. COMCOT-SS (COrnell Multi-grid Coupled Tsunami Model – Storm Surge) fulfils above-mentioned requirements and solves nonlinear shallow water equations with multi-scale wave propagations and inundation calculation. In this study, 2015 category-5 Typhoon Soulik is chosen for model validation, and the results are in a good agreement with observed data. Coastal inundation induced by Typhoon Soulik is also simulated to study the variation of storm tides and tides. By a series of strict validations and operational experiments, COMCOT storm surge operational system has been the official forecasting model at Central Weather Bureau, Taiwan since July, 2016, and has successfully predicted the storm surges induced by 2016 category-5 Typhoon Nepartak.

In this article, we provide brief overview of how mechanics and computations play a role in understanding materials growth, creating new low-dimensional materials and exploring structural defects. First, we introduce a concept of screw dislocation for describing carbon nanotube growth and derive a kinetic relationship between growth rate and chiral angle. Deeper analysis of the subtle balance between the kinetic and thermodynamic views reveals sharply peaked distribution of near-armchair nanotubes, explaining puzzling (n, n-1) types observed experimentally. A combination of ab initio calculations and Monte Carlo models further explains the low symmetry shapes of graphene on substrates. Being monoatomic chains of carbon, carbynes are shown to be strong yet flexible, and undergo metal-semiconductor transition under tension, offering promising innovations for future nanotechnology. We then reveal how metal substrates could facilitate the formation of boron monolayers whose bulk counterparts are non-layered and lower in energy. Further remarks are given to High Burger's vector graphene defects called D-loops and interfaces in hybrid graphene-BN materials, both with significant out-of plane distortion and impact on the mechanical properties. All of these computationally modeled systems have significant implications for the future use of these nanomaterials.

Various types of bacterial form adhesive aggregates on surfaces known as biofilms, which are of interest to researchers in a great variety of fields. In this paper, a continuum model based on diffusion-reaction is proposed and extended finite element method (XFEM) coupled to level set is employed to simulate the biofilm growth on ager substrate. Numerical results show the quantitative relationship between colony morphology and nutrient deletion. Comparing with experiment observation, we approve that diffusion limited regime is more appropriate than growth limited regime to describe Bacillus subtilis biofilm growth on MSgg ager substrate. Our model can be extended to investigate detailed biological process in biofilm growth such as cell subdivision and osmotic pressure induced transportation.

This work considers the possibilities of using static analysis and scanning electron microscopy techniques to determine the properties of disperse materials, i.e. corrosion resistant steel grades 12X18N9T and 20X13, taken into account in the selective laser melting technique.

Bifurcation analysis of the orthogonal cutting model with cutting force nonlinearity is presented with special attention to double Hopf bifurcations. The normal form of the system in the vicinity of the double Hopf point is derived analytically by means of center manifold reduction. The dynamics is restricted to a four-dimensional center manifold, and the long-term behavior is illustrated on simplified phase portraits in two dimensions. The topology of the phase portraits reveal the coexistence of periodic and quasi-periodic solutions, which are computed by approximate analytical formulas.

In this paper we employ an improved thalamo-cortical model to uncover the potential generation mechanisms of pS-WD patterns by means of bursting oscillation's analysis approaches in the process of seizures generation at both fast and slow timescales. Interestingly, it is found that the onset of epileptic discharges can be delayed as an increase of excitatory regulating function of the thalamic relay neuronal population on cortical PY. The obtained numerical results show that the initiation of absence seizures arises from the thalamus and the termination of them in the cortex.

The inner ear has two main parts, the cochlea, dedicated to hearing, and the vestibular system, dedicated to balance. Dizziness and vertigo are the main symptoms related to vestibular disorders, which commonly affects older people. In order to eliminate these symptoms a vestibular rehabilitation is performed; this consists in a range of movements of the head, known as maneuvers, performed by a clinical professional. This procedure does not always work as expected. The aim of this work is to contribute to a better understanding on how the vestibular system works. This knowledge will help in the development of new techniques that will facilitate a more efficient rehabilitation. In order to achieve that goal, a three-dimensional numerical model of the vestibular system, containing the fluids which promote the body balance, was constructed. The vestibular components will be discretized using the finite element method and the fluid flow will be analyzed using the Smoothed Particle Hydrodynamics.

The results obtained with the numerical model of the semicircular canal built to study the rehabilitation process are presented and compared with other authors. The solution achieved is similar with literature.

A coupled-process based tide-wave-surge model has been used to simulate Typhoon Cobra in December 14-19, 1944, also best known as the Typhoons of 1944 or Halsey’s Typhoon. The typhoon information of location and direction that were provided to admiral Halsey was not accurate and the third fleet operating 480 km east of Luzon in the Philippine Sea sailed into the center of the typhoon. As a result, the ship was wrecked by strong winds of 87 kt, lowest air pressure of 907 hPa and very high seas. This typhoon resulted in the establishment of Joint Typhoon Warning Center (JTWC) in Hawaii. The model was constructed with fine-mesh finite element model covering the whole South China Sea with inclusion of the Java Sea and adjacent marginal seas and the Philippine Sea. Approximate mesh sizes in the region of interest were formulated as a few tens of meters and the bathymetry of the tidal flat area was described, thus enabling a detailed representation of component in tidal characteristics in the modelled tidal regime. Typhoon and meteorological forcing inputs for the period 13-20, December 1944 are prepared via blending of ECMWF-20C as background meteorological conditions and Holland type vortex typhoon fields. The water elevation determined from the estimation of the Japanese National Astronomical Observatory (NAOTIDE) database was imposed at the tidal open boundary. Time-series outputs of storm waves are produced showing maximum significant wave heights of 12-15 m along the typhoon track.