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Ishida H.,Nagaoka National College of Technology
Journal of Fire Sciences

The propagation of a flame tip in an assisted flow along the high-temperature ground soaked with high-volatile liquid fuel was studied experimentally from the point of view of a fundamental study on the fire hazard prevention in many fuel spill accidents. The effects of flow velocity on the flame tip propagation and on the motion of flammable gas layer were investigated experimentally. The study revealed the interesting and characteristic dependence of the propagation velocity of the flame tip on the flow velocity, which is classified into three regions by the ratio of the flow velocity about 1 mm above the ground surface to the flame propagation velocity with no surrounding airflow. The flame tip blows off and no flame propagation occurs when the ratio is over about 1.5, which agrees with the blow-off of spreading flame in an opposed flow, described in detail in our previous study. The flame tip propagation in an assisted flow strongly depends on the formation of a flammable gas mixture downstream of the flow. © The Author(s), 2010. Source

Zanganeh J.,University of Newcastle | Moghtaderi B.,University of Newcastle | Ishida H.,Nagaoka National College of Technology
Progress in Energy and Combustion Science

Fires caused by accidental spillage of flammable liquids have been a major safety concern in industries and urban areas. There has been a recent surge of interest in the research concerning the combustion and flame spread over an inert porous media soaked with flammable liquid. This interest has been driven by the need to better understand fire and its behaviour under these conditions and improve the relevant fire safety and prevention technologies. A review of key studies in this subject area has been conducted and summarised, focussing mainly on the theory plus a notable experimental findings about combustion and the flame spread phenomena of fuel-soaked porous media. The review covers topics such as flame spread behaviour, physical flame propagation aspects, heat transfer, temperature distribution; and fuel consumption over inert porous media. The review concludes with some practical safety and environmental considerations for decontamination of land soaked with flammable liquid. © 2013 Elsevier Ltd. All rights reserved. Source

Matsunaga S.,Nagaoka National College of Technology
International Journal of Molecular Sciences

A molecular dynamics simulation has been performed on the greenhouse gases carbon dioxide and methane dissolved in a sodium chloride aqueous solution, as a simple model of seawatr. A carbon dioxide molecule is also treated as a hydrogen carbonate ion. The structure, coordination number, diffusion coefficient, shear viscosity, specific heat, and thermal conductivity of the solutions have been discussed. The anomalous behaviors of these properties, especially the negative pressure dependence of thermal conductivity, have been observed in the higher-pressure region. © 2015 by the authors; licensee MDPI, Basel, Switzerland. Source

Matsunaga S.,Nagaoka National College of Technology
Journal of Physics: Conference Series

The structure and thermal conductivity of the sodium chloride (NaCl) aqueous solution in similar concentration to the seawater with saturated carbon dioxide (CO2) have been investigated by molecular dynamics simulation. The effects of pressure have been investigated under various pressures corresponding to the depth of the sea from 40m to 10000m. The negative pressure dependence of the thermal conductivity has been detected in the depth of more than 8000m, whereas that of NaCl aqueous solution without CO2 shows the positive pressure dependence. © Published under licence by IOP Publishing Ltd. Source

Matsunaga S.,Nagaoka National College of Technology
Journal of Physics Condensed Matter

The theory of the premelting phenomena in ionic crystals on the basis of the concept of the heterophase fluctuation has been applied to the pseudo-binary ionic crystals, KCl-NaCl, AgBr-AgCl and AgBr-CuBr systems. Molecular dynamics simulations (MD) have been performed to examine the ionic configurations in their premelting region in the vicinity of their melting points. Liquid-like clusters have been observed in the results of MD utilizing the Lindemann instability condition. The sizes of liquid-like clusters have been estimated by theory and MD. The characteristics of the dynamical behavior of ions in the premelting region have been examined by the mean square displacement and the velocity correlation functions. © 2010 IOP Publishing Ltd. Source

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