In this paper, we first study the dynamics of hot shocks in air in cylindrical geometry coupled to multiband radiation transport and detailed air chemistry. The wide energy and length scale ranges which are covered herein includes and exceeds the ones of first and subsequent return strokes happening during lightning discharges. An emphasis is put on the NO x production and the optical power emitted by strong shocks as the ones generated by Joule heating of the air from intense current flows. The production rate of NO x , which is useful for atmospheric global modeling, is found to be between 4.5 × 10 16 and 8.6 × 10 16 molecules/J for all computed cases, which is in agreement with the literature. Two different radiation transport methods are used to characterize the variability of the results according to the radiation transport method. With the exact radiation solver, we show that between 15 and 40% of the energy is lost by radiation, with a percentage between 20 and 25% for averaged lightning energies. The maximal visible peak is between 7 × 10 8 W/m and 3 × 10 7 W/m obtained for, respectively, a 19 kJ/cm and a 28 J/cm energy input. The mean radiated powers in the visible range are found between 9 × 10 6 W/m and 2 × 10 5 W/m for the energies just mentioned. We discuss the agreement of these values with previous studies.

Numerical solutions have been obtained for the nonlinear heat conduction equations arising in the theory of thermal explosions. Explosion times are calculated for externally heated spheres, cylinders, and slabs of several explosive materials, and the results are shown to agree with experiment.

Calculation of Raman intensities for the ringpuckering vibrations of trimethylene oxide and cyclobutane. The importance of electrical anharmonicityIn the previous paper of this series, the microwave spectra of four isotopic species of trimethylene oxide were investigated and the potential function for the puckering of the four-membered ring was determined. Further analysis of the data has now enabled the molecular structure to be calculated. The structural parameters deduced from the rotational constants are: r(C-C) = 1.549±0.OO3 A, r(C-O) = 1.449±0.OO2 A, r(C,,-H,,) = 1.091± 0.002 A, r(Cp-H~)=1.100±0.OO3 A,

This paper describes theoretical model studies of the interaction of Leonid meteoroids with the earth's atmosphere. Subject to some modest-to-strenuous approximations we compute the rates of ablation and deceleration, energy deposition, and terminal altitudes of the meteors as functions of their initial mass and bulk density, velocity, trajectory entry angle, drag coefficient, heat of ablation, and an ablation energy transfer fraction. We find that the dominant energy deposition in the atmosphere is associated with the stopping of the ablated meteor particles and vapor by the surrounding air. Then having computed the energy deposition rates versus altitude we compute the hydrodynamic and radiative expansion of the hot wake material in the radial direction, along with the associated air chemistry. From the computed results we can then plot two-dimensional temperature contours -as functions of the instantaneous distance behind the meteor and radial distance from the center of the wake, at various altitudes along the meteor's path. We also compute the rates of emission of radiation and the radiative efficiency, and discuss comparisons with observations.

The microwave spectra of four isotopic species of trimethylene oxide have been investigated. Analysis of the spectra indicates that the four-membered ring is essentially planar. From the intensity measurements of the rotational transitions and their vibrational satellites, it was concluded that the energy levels in the ring-puckering vibration are single levels. The Stark effect also provided independent evidence that the ring is not highly puckered. The dipole moment of the molecule was found to lie solely on the C–O molecular axis. A value of 1.93±0.01 Debye was obtained. The existence of a small barrier in the potential function, however, was established by a detailed analysis of the observed vibration-rotation interaction. Quantitative considerations have led to an accurate determination of the barrier height and the general shape of the potential function. The barrier restricting the ring-puckering motion has been found to be 35±5 cm—1. The ground vibrational level is 8±4 cm—1 above the top of the barrier.