Comparison of Feather Assemblage between Land Bird and Water Bird

Physical Properties of Down and Feather Assemblage (Part 3)

Abstract

The physical properties of feather assemblage of the land bird has been studied, since the feather of the land bird, which is cheaper than that of the water bird, is filled up in a feather quilt, recently.
Experiments were carried out on heat transfer, compressible deformation and diffusion of humidity. Those are important factors of a feather quilt, and the results obtained were compared with those of feather assemblage of the water bird reported by authors.
The results obtained are as follows :
1) The coefficient of thermal transmission of feather assemblage of the land bird was 7.5-10 × 10^-5cal/ (cm·sec·deg) over the wide range of density of 20-200 × 10^-3g/cm³ as in the case that of the water bird.
2) The residual strain of compressible deformation of the land bird was larger than that of the water bird. The bulkiness of the land bird was smaller than that of the water bird, which was similar to that of the cotton assemblage. The barb or the barbule of the land bird was easy to break in comparison with that of the water bird owing to the differences in configurational construction.
3) The diffusion coefficient of humidity of the feather assemblage of the land bird was smaller than that of the water bird.
From these results, feather assemblage of the land bird is not suitable for wadding in a feather quilt in comparison with that of the water bird.