Atomic emission characteristics of a premixed acetylene-nitrous oxide, total consumption flame.
It is well known that most of the burners presently used to produce high temperature, premixed flames have the tendency to be discouragingly wasteful of the sample solution, often bringing only a small fraction of the amount used into the flame. This paper reports on the construction and performance of a highly efficient total consumption burner that produces a nonturbulent acetylene-nitrous oxide flame from premixed gases. The eighteen flame emission detection limits tabulated for a select group of elements compare favorably with the best values heretofore reported in the literature, and the apparent freedom of alkaline earth emission from phosphate interference indicates the total consumption flame here described to be less subject to chemical interference than is the conventional diffusion flame. The relatively low cost burner that has been developed is convenient to operate and can be quickly assembled from commercially available components.
High-Temperature Atomic and Molecular Spectroscopy
I. INTRODUCTION High-temperature spectroscopy found its real beginning in 1860 when Michael Faraday demonstrated the uniqueness of the candle as a chemical system in his six Christmas lectures. Since that time, no area of analytical chemistry has received greater or more extended attention; and it is becoming more and more evident as increased research is carried out in this field that its potential uses, not only for analytical purposes, but also for studies of the fundamental processes of atoms in the gaseous state, have only begun to be recognized. Presently, high-temperature spectrometric analytical techniques have been developed for most of the elements in the periodic table in various sample types. Methods are also under investigation which will extend this list to include many of the group VA, VIA, and VIIA elements.
Mechanics of deformable directed surfaces
Abstract The paper develops a simple, yet complete and consistent non-linear dynamic thermo-elastic shell theory based on the concepts of a two-dimensional directed continuum. The constitutive equations are postulated in a general form. Stress-strain relations are derived using the equation of energy balance and the two entropy production inequalities, which are rewritten in a special form. The linear theory is discussed in detail. The structure of the stress-strain relations is presented in the most general form and then specialized to concrete examples, in particular, to the classical shell theory, using their invariance properties with respective to certain symmetry groups. The elastic moduli are determined by demanding the coincidence of the frequency dispersion surfaces obtained using the two-dimensional theory with the lowest foils of the corresponding surfaces resulting from the three-dimensional theory of elasticity.