We investigate the formation of steady gas flows—so-called electric winds—created by point-plane corona discharges driven by time oscillating (ac) electric fields. By varying the magnitude and frequency of the applied field, we identify two distinct scaling regimes: (i) a low frequency (dc) regime and (ii) a high frequency (ac) regime. These experimental observations are reproduced and explained by a theoretical model describing the transport and recombination of ions surrounding the discharge and their contribution to the measured wind velocity. The two regimes differ in the spatial distribution of ions and in the process by which ions are consumed. Interestingly, we find that ac corona discharges generate strong electric forces localized near the tip of the point electrode, while dc corona discharges generate weaker forces distributed throughout the interelectrode region. Consequently, the velocity of the electric winds (>1 m/s) generated by ac discharges is largely independent of the position of the counter electrode. The unified theoretical description of dc and ac electric winds presented here reconciles previous observations of winds driven by dc corona and ac dielectric barrier discharges; insights from the model should also prove useful in the design of other plasma actuators.
OBJECTIVE This study examined different cooking methods for red meats in relation to type 2 diabetes (T2D) risk among U.S. women who consumed red meats regularly (≥2 servings/week). RESEARCH DESIGN AND METHODS We monitored 59,033 women (1986–2012) aged 30–55 years and free of diabetes, cardiovascular disease, and cancer at baseline when information on frequency of different cooking methods for red meats, including broiling, barbequing, roasting, pan-frying, and stewing/boiling, was collected. RESULTS During 1.24 million person-years of follow-up, we documented 6,206 incident cases of T2D. After multivariate adjustment including red meat cooking methods, total red meat and processed red meat intake were both associated with a monotonically increased T2D risk (both P trend <0.05). After multivariate adjustment including total red meat intake, a higher frequency of broiling, barbequing, and roasting red meats was each independently associated with a higher T2D risk. When comparing ≥2 times/week with <1 time/month, the hazard ratios (HRs) and 95% CI of T2D were 1.29 (1.19, 1.40; P trend <0.001) for broiling, 1.23 (1.11, 1.38; P trend <0.001) for barbequing, and 1.11 (1.01, 1.23; P trend = 0.14) for roasting. In contrast, the frequency of stewing/boiling red meats was not associated with T2D risk, and an inverse association was observed for pan-frying frequency and T2D risk. The results remained similar after cooking methods were further mutually adjusted. CONCLUSIONS Independent of total red meat consumption, high-temperature and/or open-flame cooking methods for red meats, especially broiling and barbequing, may further increase diabetes risk among regular meat eaters.
The durability of thermal barrier coatings is governed by a sequence of crack nucleation, propagation and coalescence events that accumulate prior to final failure by large scale buckling and spalling. Because of differing manufacturing approaches and operating scenarios, several specific mechanisms are involved. These mechanisms have begun to be understood. This article reviews this understanding and presents relationships between the durability, the governing material properties and the salient morphological features. The failure is ultimately connected to the large residual compression in the thermally grown oxide through its roles in amplifying imperfections near the interface. This amplification induces an energy release rate at cracks emanating from the imperfections that eventually buckle and spall the TBC.
No abstract is provided for this article.
