Computational Analysis of Zel'dovich-von Neumann-Doering (ZND) Detonation

The Transient Inlet Concept (TIC) involves transient aerodynamics and wave interactions with the objective of producing turbulence, compression and flow in ducted engines at low subsonic speeds. This concept relies on the generation and control of multiple detonation waves issuing from different ?stages? along a simple ducted engine, and aims to eliminate the need for compressors at low speeds. Currently, the Zel?dovichvon Neumann-Doering (ZND) steady, one-dimensional detonation is the simplest method of generating the waves issuing from each stage of the TIC device. This thesis focuses on the primary calculation of a full thermochemistry through a ZND detonation from an initially unreacted supersonic state, through a discontinuous shock wave and a subsonic reaction zone, to the final, reacted, equilibrium state. Modeling of the ZND detonation is accomplished using Cantera, an open-source object-oriented code developed at Caltech. The code provides a robust framework for treating thermodynamics, chemical kinetics, and transport processes, as well as numerical solvers for various reacting flow problems. The present work examines the effects of chemical kinetics on the structure of ZND detonation, by using a detailed chemical kinetics mechanism that involves 53 species and 325 simultaneous reactions (Gas Research Institute 3.0). Using a direct integration of the system of inviscid ordinary differential equations for the ZND detonation, I obtain results for the combination of different fuels (hydrogen and methane) and oxidizers (oxygen and air). The detailed thermochemistry results of the calculations are critically examined for use in a future induced-detonation compression system

Intermittent Beginning to the Formation of Hydrogenous Ferromanganese Nodules in the Vast Field: Insights from Multi-Element Chemostratigraphy Using Microfocus X-ray Fluorescence

南極からの海洋深層水が「国産コバルト資源」を生み出した --南鳥島周辺に広大なマンガンノジュール密集域が形成された原因を特定--. 京都大学プレスリリース. 2022-01-12.Vast ferromanganese nodule fields have been found on the deep-sea floor of all oceans worldwide. They have received attention because they potentially provide high-grade metal resources to develop future high- and green-technology. However, how these vast nodule fields were formed and developed owing to their widespread nature or tendency to be denser with an increasing number of nodules has not yet been established. In this study, the fine-scale inner structure of nodules of various sizes was analyzed on the basis of chemical mapping using microfocus X-ray fluorescence. We found that nodules distributed in the vast field around Minamitorishima (Marcus) Island have several types of innermost layers, which correspond to different chemostratigraphic layers of nodules that have been previously reported by us in this region. As nodules grow in order from the center to the outside, the different types in the innermost layer indicate a difference in the timing of the beginning of their growth. Moreover, because the differences in the chemical features of each layer reflect differences in the composition of the original deep-sea water, our results imply that the beginning of nodule formation occurred intermittently at each time of a water mass replacement due to new deep-sea currents flowing into this region. We recognized that the northern part of the study area was dominated by large nodules that started to grow in relatively earlier times, while the southern part tended to have many nodules that grew in relatively later times. Based on these observations, we hypothesize that the intermittent beginning of nodule formation is governed by the northward inflow of the deep-sea current that originated from the Lower Circumpolar Deep Water for an extended time to form the vast nodule field. Because patterns in the timing of nodule formation were different in the eastern and western regions, we thus further propose that the topographic framework, i.e., the arrangement of individual large seamounts and the cluster of small knolls and petit-spot volcanoes, strongly regulates the flow path of the deep-sea current, even if the position of the entire seamount changes owing to plate motion. The deep-sea current might supply some materials to be nuclei, resulting in the nodule formation at the beginning of the process

Atmospheric response to anomalous sea ice in the Sea of Okhotsk

第6回極域科学シンポジウム[OM] 極域気水圏11月16日（月）　国立極地研究所１階交流アトリウ

Kinetics of Electron-Beam Dispersion of Fullerite C60

Electron-beam dispersion of pressed fullerite C60 targets in vacuum leads to the deposition of thin films containing polymeric forms of C60. The aim of the present report is to analyze physical-chemical processes in the fullerite target during its electron-beam dispersion through the analysis of the kinetics of the radiation temperature of the target surface, the coating growth rate and the density of negative current on the substrate. It was shown that the induction stage of the process is determined by the negative charging and radiation-induced modification and heating of the target. The transitional stage is characterized by nonstationary sublimation of the target material through the pores in the modified surface layer and release of the accumulated negative charge. Stabilization of the process parameters owing to the convection cooling of the target by the sublimation products and the decrease in the pressure inside the microcavities beneath the pores leads to a quasi-stationary stage of target sublimation and deposition of a coating containing polymeric forms of C60.Comment: 13 pages, 6 figure