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

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.

Commentary: The case for caution in predicting scientists’ future impact

We stress-test the career predictability model proposed by Acuna et al. [Nature 489, 201-202 2012] by applying their model to a longitudinal career data set of 100 Assistant professors in physics, two from each of the top 50 physics departments in the US. The Acuna model claims to predict h(t+\Delta t), a scientist's h-index \Delta t years into the future, using a linear combination of 5 cumulative career measures taken at career age t. Here we investigate how the "predictability" depends on the aggregation of career data across multiple age cohorts. We confirm that the Acuna model does a respectable job of predicting h(t+\Delta t) up to roughly 6 years into the future when aggregating all age cohorts together. However, when calculated using subsets of specific age cohorts (e.g. using data for only t=3), we find that the model's predictive power significantly decreases, especially when applied to early career years. For young careers, the model does a much worse job of predicting future impact, and hence, exposes a serious limitation. The limitation is particularly concerning as early career decisions make up a significant portion, if not the majority, of cases where quantitative approaches are likely to be applied.Comment: 2 pages, 1 figur

A dynamic aerosol module for global chemical transport models: Model description

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94951/1/jgrd11164.pd

Permutation combinatorics of worldsheet moduli space

52 pages, 21 figures52 pages, 21 figures; minor corrections, "On the" dropped from title, matches published version52 pages, 21 figures; minor corrections, "On the" dropped from title, matches published versio

Global 2-D intercomparison of sectional and modal aerosol modules

International audienceWe present an intercomparison of several aerosol modules, sectional and modal, in a global 2-D model in order to differentiate their behavior for tropospheric and stratospheric applications. We model only binary sulfuric acid-water aerosols in this study. Three versions of the sectional model and three versions of the modal model are used to test the sensitivity of background aerosol mass and size distribution to the number of bins or modes and to the prescribed width of the largest mode. We find modest sensitivity to the number of bins (40 vs. 150) used in the sectional model. Aerosol mass is found to be reduced in a modal model if care is not taken in selecting the width of the largest lognormal mode, reflecting differences in sedimentation in the middle stratosphere. The size distributions calculated by the sectional model can be better matched by a modal model with four modes rather than three modes in most but not all situations. A simulation of aerosol decay following the 1991 eruption of Mt. Pinatubo shows that the representation of the size distribution can have a signficant impact on model-calculated aerosol decay rates in the stratosphere. Between 1991 and 1995, aerosol extinction and surface area density calculated by two versions of the modal model adequately match results from the sectional model. Calculated effective radius for the same time period shows more intermodel variability, with a 20-bin sectional model performing much better than any of the modal models

Single seed sorting technology and its interaction with processing for food, malt, feed and industrial markets

Non-Peer Reviewe