Dual-mode sorption kinetics of gases in glassy polymers

The transport of gases in many glassy polymers can be described satisfactorily by means of a “dual-mode sorption” model. The transport behavior observed with a given gas/polymer system can be characterized by the model parameters, which are obtained from solubility measurements in conjunction with absorption/desorption or permeability measurements. The present study discusses the inverse problem, namely, the prediction of the absorption/desorption behavior of a gas in a glassy polymer from a specified set of dual-mode sorption parameters. Satisfactory agreement is obtained between reported absorption rates of sulfur dioxide in glassy polycarbonate and of water vapor in Kapton® ?

1 ?Trademark of E. I. du Pont de Nemours & Co.

and the rates predicted by the dual-mode sorption model. This study also confirms the consistency of the model.     

Partial muon capture rates in 12C from the generalized helm model

Partial capture rates in the reaction μ^? + ¹²C → ν_μ + ¹²B are calculated using the generalized Helm model. The results are in good agreement with the recent experiment data.     

Effect of container material, storage time and temperature on determinations of cadmium levels in human urine

The effect of container material (polyethylene, polypropylene, polystyrene, borosilicate glass and flint glass), storage time (0-86 days), and temperature (22 degrees and 4 degrees ) on the cadmium content found by graphite-furnace atomic-absorption spectrometry for spiked and unspiked urine samples has been studied. No loss of cadmium occurred for at least 10 and 28 days when unspiked and spiked samples respectively, were stored in polyethylene containers at 22 degrees . For storage up to 3-4 days at 22 degrees , polypropylene, polystyrene, borosilicate glass and flint glass containers were also found suitable. Storage at 4 degrees was not effective in preventing loss of cadmium.     

The crystal and molecular structure of N-(17-methoxy-phenyl)-2-chloropyrrolo (2,3- b ) quinoline

N-(17-methoxy-phenyl)-2-chloropyrrolo (2,3-b) quinoline was solved by direct methods and refined to anR of 0.104 for 950 observed reflections. The intensity data were collected by the multiple film equi-inclination Weissenberg technique and estimated visually. The packing of the molecule is stabilised by van der Waals interaction. The pyrrolo (2,3-b) quinoline ring system is planar and the methoxy phenyl ring is approximately perpendicular to the plane of this ring system with a dihedral angle of 86.5°.     

An algebraic approach to the restoration of images

Two different matrix algorithms are described for the restoration of blurred pictures. These are illustrated by numerical examples.