Impact of gender, age and experience of pilots on general aviation accidents

General aviation (GA) accounts for more than 82% of all air transport-related accidents and air transport-related fatalities in the U.S. In this study, we conduct a series of statistical analyses to investigate the significance of a pilot's gender, age and experience in influencing the risk for pilot errors and fatalities in GA accidents. There is no evidence from the Chi-square tests and logistic regression models that support the likelihood of an accident caused by pilot error to be related to pilot gender. However, evidence is found that male pilots, those older than 60 years of age, and with more experience, are more likely to be involved in a fatal accident.     

The origin of a 650 nm photoluminescence band in rubrene

Commonly observed variations in photoluminescence (PL) spectra of crystalline organic semiconductors, including the appearance or enhancement of certain PL bands, are shown to originate from a small amount of structural disorder (e.g., amorphous inclusions embedded in a crystal), rather than be necessarily related to chemical impurities or material oxidation. For instance, in rubrene, a minute amount of such disorder can lead to the appearance of a dominant PL band at 650 nm as a result of triplet excitons captured and fused at these sites, with a subsequent emission from the amorphous phase.     

Numerical study of turbulent flame velocity

A premixed flame propagating through a combination of vortices in a tube/channel is studied using direct numerical simulations of the complete set of combustion equations including thermal conduction, diffusion, viscosity, and chemical kinetics. Two cases are considered, a single-mode vortex array and a multimode combination of vortices obeying the Kolmogorov spectrum. It is shown that the velocity of flame propagation depends strongly on the vortex intensity and size. The dependence on the vortex intensity is almost linear in agreement with the general belief. The dependence on the vortex size may be imitated by a power law ∝D2/3. This result is different from theoretical predictions, which creates a challenge for the theory. In the case of the Kolmogorov spectrum of vortices, the velocity of flame propagation is noticeably smaller than for a single-mode vortex array. The flame velocity depends weakly on the thermal expansion of burning matter within the domain of realistically large expansion factors. Comparison to the experimental data indicates that small-scale turbulence is not the only effect that influences the flame velocity in the experimental flows. Large-scale processes, such as the Darrieus-Landau instability and flame-wall interaction, contribute considerably to the velocity of flame propagation. Still, on small scales, the Darrieus-Landau instability becomes important only for a sufficiently low vortex intensity.     

Thermophysical properties of compressor oils for refrigerating plant

In the present study, an accurate experimental information for the widely used commercial refrigerating compressor oils ONF 46, ACD 100 FY, Azmol, FR 32, XC 15, XC 40 and WF 15A is presented. Experimental data on the capillary constant, surface tension, density, refractive index and kinematic viscosity at the temperature range from 293 to 353 K for seven commercial compressor oils are reported. In addition, the experimental data on the isobaric heat capacity at temperature range from 288 to 393 K, the vapor pressure at liquid‐saturated curve and average molecular weight for four commercial compressor oils are firstly presented in the paper. The data obtained are fitted by few‐constant correlations. Based on results obtained, the values of pseudocritical temperature for the compressor oils have been determined. Copyright © 2008 John Wiley & Sons, Ltd.     

Intracellular pH Sensor Based on Heteroleptic Bis-Cyclometalated Iridium(III) Complex Embedded into Block-Copolymer Nanospecies: Application in Phosphorescence Lifetime Imaging Microscopy

Herein, a novel pH-responsive phosphorescent probe based on cyclometalated iridium(III) complex is reported. To prevent oxygen quenching of phosphorescence and to improve the probe biocompatibility, the complex is covalently conjugated with a water-soluble block-copolymer that also increases its pH sensitivity. The resulting polymeric nanoprobe demonstrates a strong response of the phosphorescence lifetime onto pH variations in physiological range. Cellular experiments with Chinese hamster ovary (CHO-K1) cells show the predominant internalization of the probe in acidified cell compartments, endosomes and lysosomes. The analysis of phosphorescence lifetime imaging microscopy data confirms applicability of the sensor for monitoring of intra- and extracellular pH in cell cultures.