Explanation of the Fractal Characteristics of Goose Down Configurations

Abstract

Down is a layer of undercoat growing on the cuticular of fowl, such as geese, ducks and swans, etc. Goose down and duck down are thereinto the most usual down, which and very soft and fine in nature. For a long time, down has been used as the best filler material for bedding and outerwear, able to withstand cold climates because of its superior thermal insulating properties. The investigation of the configuration characteristics and thermal insulation mechanisms of down and down assemblies have never stopped, and there are several publications [1-4] on the morphology and structure, as well as physico-chemical properties, of down. However, using mathematical methods and fractal theory to characterize down structure and further to explain heat transfer problems in single down and down assemblies has never been attempted up to now.In this paper, we attempt to describe the configuration characteristics of goose down quantitatively using tools from fractal geometry and local fractal dimensions, as well as pioneering research on the heat transfer problems and thermal insulation properties of down and down assemblies. Before presenting the structure analysis, a general background of fractal geometry and the essential concepts of the "local fractal dimension" are briefly reviewed in the following section.

Influence of Chemical Structure on Wetting Property of Down Fibers

“…Down fiber belonged to natural protein fibers. Down keratin was composed of species of alpha-amino-acid, occupied the total weight 97.94% [6]. These amino-acid molecules linked into polypeptide chains forming the primary structure of down keratin.…”

“…These amino-acid molecules linked into polypeptide chains forming the primary structure of down keratin. Also there were transverse links, like salt bond links, amino bond links, ester linkage links, disulfide bond links and hydrogen bond links, condensed by most these alpha-amino-acid among the down keratin macromolecules [6].…”

Down Fiber Reinforced Cellulose Nanofiber Aerogel toward Thermal Insulation and Pollutant Removal

“…As a component of the connecting/winding filler, it is important to improve the mechanical property of composite aerogels. The unique hollow structure has great potential and development prospects for adsorption and thermal insulation. , Moreover, DF is also a kind of good high-temperature resistant material, − and has outstanding absorption capacity for dyestuff and high dye removal efficiency. − …”

Relationship between Fractal Dimension and Structure of Nonwovens

“…Shi [3] used two fractal parameters to build up the relationship between structure of fiber bundle and the vertical wicking height. Gao [4][5][6] studied the fractal dimension of goose down and proposed that the near optimal fractal dimension may be attributable for the excellent thermal insulation and breath-ability of goose down. Fan [7] provided a new interpretation for the relationship between fractal dimension of wool fiber and its warmth-retaining property.…”