Experimental determination of rotational temperatures and concentrations of OH in flames from emission spectra

In order to illustrate the use of two‐path experiments for correcting for self‐absorption, experimental studies to determine the rotational "temperatures" and concentrations of OH in flames burning at atmospheric pressure have been carried out. For mixtures of H_2, C_2H_2, and O_2, as well as for C_2H_2-O_2 flames diluted with A, "anomalous" rotational "temperatures" were observed under conditions in which strong self‐absorption was clearly indicated by the intensity ratios for the double‐path to the single‐path experiments. Unequivocal quantitative estimates of rotational temperatures and of OH concentrations cannot be carried out, even on the assumption that the emitting system is isothermal and in equilibrium. However, by using the results of theoretical studies on two‐path experiments carried out by one of us, it is possible to obtain reasonable upper limits for the temperatures and lower limits for the OH‐concentrations, based on an assumed Doppler contour for the line‐shape and utilizing Oldenberg's estimates for the f values of representative spectral lines. Our experimental studies lead to reasonable rotational temperatures at the tip of luminous cones for mixtures of H_2, C_2H_2, and O_2 and for C_2H_2-O_2 flames diluted with up to 60 percent argon. These observations do not disprove the reality of rotational temperature anomalies in the inner cones of flames. Significant improvement of experimental procedure, and quantitative interpretation of results along the lines used by us, requires additional basic studies with emphasis on the measurement of spectral line‐shape and absolute intensitie

Filtered screens and augmented Teichm\"uller space

We study a new bordification of the decorated Teichm\"uller space for a multiply punctured surface F by a space of filtered screens on the surface that arises from a natural elaboration of earlier work of McShane-Penner. We identify necessary and sufficient conditions for paths in this space of filtered screens to yield short curves having vanishing length in the underlying surface F. As a result, an appropriate quotient of this space of filtered screens on F yields a decorated augmented Teichm\"uller space which is shown to admit a CW decomposition that naturally projects to the augmented Teichm\"uller space by forgetting decorations and whose strata are indexed by a new object termed partially oriented stratum graphs.Comment: Final version to appear in Geometriae Dedicat

Interference effects during burning in air for stationary n-heptane, ethyl alcohol, and methyl alcohol droplets

Experiments have been conducted for the determination of the evaporation constant and flame shapes of two and of five closely spaced droplets burning in air. Droplets of approximately the same and of different diameters were used at various distances between the droplet centers. The apparent flame shape, which was observed only for n-heptane droplets, changes very little during burning. The square of the droplet diameter decreases linearly with time for fixed spacing between droplet centers, at least within the experimental limits of accuracy. In general, the average evaporation constant for two droplets, K', must be assumed either to vary continuously during burning or else to be a function of average initial drop diameter, D^0. The change of K' with time corresponds to the second derivative in plots of the square of the diameter vs. time. These second derivatives are not defined in our work because of unavoidable scatter of the experimental data. Attempts at understanding the observed results by considering published theories for single droplets, as well as groupings obtained from dimensional analysis, have been unsuccessful. It appears that the diffusion model for the heterogeneous burning of single fuel droplets will require serious revision and extension before the burning of droplets arrays and sprays can be understood quantitatively. Furthermore, the effective value of K' for a spray probably depends not only on the fuel-oxidizer system but also on the injection pattern. For this reason additional studies had best be carried out under conditions corresponding to those existing in service models

Nomogram for the Evaluation of Blackbody Radiancy and of Peak and Total Intensities for Spectral Lines with Doppler Contour

A nomogram has been constructed for the determination of blackbody radiancy and of peak and total intensities for spectral lines with Doppler contour. The basic equations used for the construction of the nomogram and the use of the nomogram are described briefly. A method is outlined for determining absolute values of total intensities for spectral lines with combined Doppler and resonance contour by using the nomogram in conjunction with the “curves of growth.

Natalia Andronova (1953–2014)

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108617/1/eost2014EO390006.pd

EC78-965 Planning Meals for Groups

Extension Circular 78-965 is about planning meals for large groups

EC78-965 Planning Meals for Groups

Extension Circular 78-965 is about planning meals for large groups

Approximate theoretical performance evaluation for a diverging rocket

A simplified combustion model, which is motivated by available performance studies on the diverging rocket reactor, has been used as basis for an engine performance evaluation. Comparison with conventional rocket configurations shows that an upper performance limit for the diverging reactor is comparable with performance estimates for engines using an adiabatic work cycle. Development of the diverging reactor for engine applications may, however, offer some advantages for very hot, high-energy, propellant systems