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The evaluation of the performance of a particular inflator for the design of the entire airbag system is typically carried out by examining the pressure pattern in a standard tank test. This study assesses the adequacy of the tank test as a true measure of the likely performance of the actual inflator-airbag system. Theoretical arguments, numerical experiments, and physical experiments show that the time rate of pressure change may be an appropriate measure to evaluate performance of a specific type of inflator, particularly if variations in the inflator design maintain the same working gas components. However, when evaluating and comparing the dynamic behavior between different types of inflators, the time rate of pressure change provides useful but incomplete information.

A correlated high-speed image and E-field observation of natural lightning attachment process on a time scale of sub-microsecond has been performed. In one of the observed events, downward stepped leader pulses can be clearly identified either in E-filed or optical signals. When the stepped leader approaches within about three hundred meters of ground, optical pulses begin to appear in the lowest 40 m channel section. These pulses have larger amplitude than the pulses from the downward stepped leader. It appears that these pulses are produced by an upward connecting leader. These facts suggest that the upward connecting leader is also stepped and it could produce even stronger pulses than the corresponding downward leader. The downward stepped leader has a velocity of about 4x106 m/s, while the upward leader has the velocity of about 1.7x106 m/s. The return stroke pulses observed in the E-field and in the optical signal agree well in time but differ in fine structures.

Deployment of an airbag or charging of a tank by an inflator-canister system is a highly dynamic process. Quantification of energy storage, energy flux, work done, flow rates, thermodynamic properties, and energy conservation are essential to describe the deployment process. The concepts of available work and entropy production are presented as useful parameters when evaluating airbag aggressivity from tank test results for different types of inflators. This paper presents a computational methodology to simulate a pyro- and a hybrid-inflator-canister-airbag system to predict the force pattern that could occur on an out-of-position occupant when the airbag deploys. Comparisons with experimental data have been made in all cases where data were available. These include driver-, passenger-, and side-airbag designs.

The highly dynamic process in a pyrotechnic inflator and in a canister-airbag system was simulated by using two compressible gas thermal energy numerical models. First a 2-D model was used to simulate flow through the inflator porous media; then results from the first model were used as input to a second 2-D model to compute pressure, temperature and flow patterns in the airbag. Results show a complete picture of the dynamics of the airbag inflator - canister system during deployment.

Some special features of cloud-to-ground (CG) lightning discharges in the verge of Qinghai-Tibetan Plateau have been found by using the data from wide-band slow antenna system with 1μs time resolution. It has been found that (CG) lightning usually follows intracloud (IC) discharges. K-changes during the IC discharge part initiate from negative charge region and propagate downward to the lower positive charge region with an average speed of 1.5×107 m/s. The radiation waveforms of return stoke begin with a slow front which last for about 9.4 μs to about half of the field peak amplitude, and the zero-to-peak rise time was 10.9μs for negative first return strokes.