Simulation of Hydrogen/Air Laminar Diffusion Flame

A model as precise as possible both from chemical reactions and fluid mechanics was constructed and applied to simulate a laminar hydrogen/air diffusion flame. The combustion conditions were given as that the burner is 10 mm in diameter, and hydrogen issues with the Poiseuille flow with 10 ml/s of the axial volumetric velocity. The obtained results were as follows. The flame is well-developed as a typical diffusion flame at about 10 mm in height. At this height, the flame-sheet assumption is valid. On the contrary, hydrogen atoms diffusing axially from a downstream region, and oxygen entrained with the radial flow of the environmental air, react at a height as low as 2 mm. This reaction produces hydroperoxyl radicals and releases a fairly large amount of thermal energy at the same time. Thereby, enthalpy is carried to the upperstream region in the form of chemical energy. The flame holding of this flame can be ascribed to these low-temperature reactions

A Reaction Scheme Applicable to Combustion of C₁- and C₂-Hydrocarbons

A reaction scheme is constructed for the combustion of simple fuels. It comprises C₁ and C₂ species and does not contain higher hydrocarbons. The rate constants are mainly determined on the basis of Westbrook's and Warnatz's reaction schemes, but some of them must be changed to make the scheme comprehensive. This reaction scheme and a mathematical model for one-dimensional premixed flames are applied to methane/air flames under various equivalence ratios and acetylene, ethylene and ethane flames under their stoichiometric conditions. The validity of the proposed scheme is verified by comparing the predicted burning velocities with this scheme and the experimental ones under the corresponding conditions. The mechanism of the combustion reactions in the above hydrocarbon flames are analyzed. In the methane flames, the reaction paths through C₂ species cannot simply be neglected. The reaction scheme where the C₂ species are omitted cannot reproduce the satisfactory burning velocities for these flames. In the acetylene flame, active C₂H₃ radicals are produced at low temperatures and are converted again to C₂H₂ at higher temperatures. In the ethylene flame, C₂H₄ reacts through C₂H₂. In the ethane flame, more than half of C₂H₆ is oxidized through C₁-species reaction paths

Simulation of Hydrogen/Air Premixed Flames Propagating in a Spherical Vessel

A mathematical model for an unsteady flame is established and applied to hydrogen/air premixed flames propagating spherically in a closed vessel. The model proposed in this investigation comprises the full reaction scheme for hydrogen combustion. It contains twenty-one elementary reactions and nine chemical species. The predicted burning velocities of hydrogen/air premixed flames with various combustion conditions are in good agreement with the experimental ones. The linearity between the mass fraction of the burnt gas and the pressure proposed by Lewis and von Elbe is reproduced and verified to be valid, especially at the early stages of combustion. The reaction mechanism of hydrogen/air premixed flames propagating unsteadily is fairly similar to that of the steady flames. It can be divided into two parts, the low-temperature mechanism and the high-temperature mechanism. The boundary temperature is around 1000K in all the flames. In a low-temperature region, the necessary amount of thermal energy to heat the combustible gas mixtures up to the boundary temperature is supplied in the form of chemical energy. It is transferred by the hydrogen atoms diffused from the flame fronts, and released mainly through the recombination reaction with oxygen

Nuclear resonant scattering of synchrotron radiation by physisorbed Kr on TiO2_{2}(110) surfaces in multilayer and monolayer regimes

Physisorbed Kr layers on TiO$_{2}$(110) surfaces were investigated by means of nuclear resonant scattering (NRS) of synchrotron radiation at Kr thicknesses ranging from multilayer to monolayer. The NRS intensity was measured as a function of the Kr exposure, from which the NRS signal corresponding to monolayer was estimated as 0.23 cps. The time spectra measured at various thicknesses showed a monotonous decay without any quantum beat features. The recoiless fraction $f$ evaluated from the analysis of the time spectrum revealed a substantial reduction upon temperature rise from 19 to 25 K. As its origin, an order-disorder phase transition of the monolayer Kr is proposed.Comment: 7 pages, 6 figure

New solution of the N=2\mathcal{N}=2 Supersymmetric KdV equation via Hirota methods

We consider the resolution of the $\mathcal{N}=2$ supersymmetric KdV equation with $a=-2$ ($SKdV_{a=-2}$) from the Hirota formalism. For the first time, a bilinear form of the $SKdV_{a=-2}$ equation is constructed. We construct multisoliton solutions and rational similarity solutions.Comment: 7 pages, 9 figures. arXiv admin note: significant text overlap with arXiv:1104.059

Neurofibromatosis type Ⅰ(von Recklinghausen's disease) の遺伝子診断および同疾患特異的 induced pluripotent stem cells (iPSCs)のインテグレーションフリー・フィーダー細胞フリー・無血清培養系での樹立による疾患研究

広島大学(Hiroshima University)博士(歯学)Doctor of Philosophy in Dental Sciencedoctora

ニオイ センサー カイハツ オ モクテキ ト シタ キュウカク ジュヨウタイ ハツゲン コウボ ノ コウチク

博士（工学）東京農工大