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The inner flow containing the ignition process of a throatless and diverging (constant diverging angle α = 5 deg) rotating detonation engine (RDE) was experimentally investigated by both optical observation and pressure measurement. An RDE that had an acrylic engine wall with a length of 70 mm and an inlet diameter of 20 mm was tested under a low back pressure condition using gaseous C 2 H 4 − O 2 as the propellants. A high-speed camera captured the ignition process, of which there were two types: deflagration-to-detonation transition and direct initiation. In addition to the visualizations of the inner flow, the pressure values in an RDE with an acrylic wall were compared with those of an RDE having a stainless steel wall with 8 pressure ports in the axial direction. The comparison revealed that the RDE exhaust flow was supersonic. A strong self-luminescence and CH* luminosity area near the injector surface during combustion suggested that the short completion of detonation combustion enabled the thermal choking of the subsonic propellant gases even when the channel was diverging. Moreover, the axial position of the erosion in the acrylic wall indicated that the heat release region was near the injector surface. Finally, a theoretical flow model for the RDE was compared to the experimental data, and the results suggested that the inner flow in the RDE can be reasonably described as a quasi-one-dimensional steady flow. [ABSTRACT FROM AUTHOR]

Background and purpose: The purpose of the present study was to examine the mid-term clinical and angiographic outcomes of patients with ST-segment elevation myocardial infarction (STEMI) who presented within 48 h and received paclitaxel-eluting stents (PES) or sirolimus-eluting stents (SES). Methods and results: This study was a retrospective, non-randomized, single-center study. The post-discharge clinical outcomes of 357 consecutive patients who presented within 48 h of their first STEMI and received PES (n = 163) or SES (n = 194) between February 2007 and February 2009 were analyzed in May 2011. The incidence of post-discharge events (i.e. cardiac death and non-fatal recurrent MI) after PES placement (0.6%) did not significantly differ from that after SES placement (1.5%). Treatment with PES was not related to the risk of adverse events post-discharge (mean follow-up period for PES placement, 1170 ± 243 days; hazard ratio, 0.346; 95% CI, 0.036-3.371; p = 0.361). No definite stent thromboses developed after treatment with PES or SES. The incidence of binary in-stent restenosis (stenosis of more than 50% of the diameter at secondary angiography performed 10-18 months after the initial procedure) after PES placement (17.1%) was significantly higher than that after SES placement (4.8%; p < 0.001). PES placement was an independent predictor of binary in-stent restenosis (odds ratio, 3.892; 95% CI, 1.470-10.30; p = 0.006). Conclusions: Retrospective examination of the post-discharge clinical course after placement of PES and SES showed favorable midterm clinical outcomes among Japanese STEMI patients treated within 48 h of onset. However, SES treatment resulted in superior angiographic outcomes compared to PES. [ABSTRACT FROM AUTHOR]