A study of the radio-activity of certain minerals and mineral waters.

Abstract

A considerable number of minerals are known in varying degrees to be radio-active. Lists have been given by M. and Madame Curie and by Sir W. Crookes, Except in the case of pitchblende, little has been done to determine the nature of the radio-active constituents; or to decide whether any hitherto unknown radio-active body is present.

Long duration of the Balmer spectrum in excited hydrogen

“…Results obtained with metallic vapours (Strutt 1914a, suggest th at in their case the duration is much longer than most theoretical discussions of the subject would lead one to anticipate, since mercury vapour, for example, can be made to pass in the luminous condition down long tubes, and it can be shown th at the same applies to other metallic vapours.…”

Fabrication and analysis of side‐emitting poly(methyl methacrylate) fibres with non‐circular cross‐sections

“…Light scattering can be described by various theories, which mainly differ by the sizes and shapes of the scattering centres as well as their distributions. Since Plexiglas® LD96 contains fillers with very small diameters in the nanometric range, we can describe the side emission by Rayleigh scattering, which occurs for scattering particles in the range of optical wavelengths (633 nm, red light, in our case) . Since Rayleigh scattering directs part of the propagating light to the sides – a desired effect for illumination applications – it leads to losses.…”

Atmospheric pressure active nitrogen (APAN) - a new source for analytical emission spectroscopy

“…The first extensive study on the nature of nitrogen afterglows was made in 1900 by E. P. Lewis, who identified the band spectra from the afterglow as originating from molecular nitrogen (2)(3)(4). A series of papers by R. J. Strutt (Lord Rayleigh) beginning in 1911 demonstrated that the afterglows obtained from nitrogen at low pressures (1-10 torr) were highly reactive with other molecules or atoms introduced into the afterglow (5)(6)(7)(8). The high degree of activity observed by Strutt led to the commonly used term "active nitrogen."…”

“…The hydride generator is shown schematically in The Ng carrier stream [3] passed through a stopcock [4] into the sample chamber [5], whose internal volume was approximately 15 mL. A gas dispersion tube [6] assured rapid reagent mixing and removal of the gaseous hydrides. The hydrides were swept through a second stopcock [7] into the APAN afterglow [8].…”

“…A gas dispersion tube [6] assured rapid reagent mixing and removal of the gaseous hydrides. The hydrides were swept through a second stopcock [7] into the APAN afterglow [8]. A third stopcock [9], located at the bottom of the cell, was used to drain reacted solutions from the sample chamber.…”