Participation in outdoor activities can improve mental, physical and social well-being. Such activities also present significant physiological strain and risks such as hypothermia; therefore, correct choice and usage of clothing is extremely important. The aim of this review is to critically analyse the literature regarding outdoor clothing systems, focusing on the layers comprising a typical clothing system. Additionally, alternative systems, potential improvements and future trends are discussed.

Clothing systems for outdoor activities

In this paper, we investigate fiber diameter and strength distributions in early-stage processing. We have processed two lots of merino wool from scouring to top finishing. Fiber samples collected at each processing stage are measured for diameter on an optical fiber diameter analyzer, and fiber strength is measured on a modified WIRA single fiber strength tester. Fiber diameter conforms to a lognormal distribution, and this conformity persists throughout early-stage processing. Single fiber strength also conforms to a lognormal distribution in general, but this conformity may be distorted by fiber damage in processes such as carding. Furthermore, we have established a formula to estimate the coefficient of variation of single fiber strength once we know the coefficient of variation of the fiber diameter.

Diameter and Strength Distributions of Merino Wool in Early Stage Processing

The last several decades have seen significant developments to the revolving-flats card and much research has been published on the fundamentals of the carding process. There are still, however, contradictions in the detailed explanation of fibre behaviour during carding and in the effectiveness of certain developments widely accepted as beneficial. This paper presents a critical review of the literature concerning the way fibre mass is disentangled into individual fibres to form a card sliver and the effectiveness of principal machine components. Areas are indicated where further research is necessary to resolve contradictory views and further the understanding of the process.

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Fibre dynamics in the revolving-flats card. Part I A critical review

The microdamage caused to wool fibres by a sliver opening process is studied by scanning electron microscopy. Transverse and longitudinal cracks, holes, and crushed regions are formed on the surface of test fibres. The likely causes of crack initiation and its weakening effect on the mechanical properties of fibres are discussed.

Wool-fibre Microdamage Caused by Opening Processes Part I: Sliver Opening

The tensile strength of wool during pre-spinning processing is examined in this paper. Both single fiber breaking load and fiber bundle strength are studied. The results confirm that carding causes more fiber damage or strength loss than other processes examined. The breaking load of fibers in combed sliver may be significantly higher than that in carded sliver, because combing breaks weak fibers damaged in carding and increases the average fiber diameter in combed sliver by removing some fine fibers. An attempt is made to generate an ideal bundle strength profile from single fiber tensile curves. Compared with the tensile curve of the ideal fiber bundle, the tensile curve of an actual wool bundle shows a relatively higher elongation and lower tenacity, probably due to the between-fiber interactions and relatively poorer fiber orientation in the actual wool bundle. A method of minimizing fiber interaction during bundle strength testing is proposed.

A Study of Wool's Tensile Strength in Early Stage Processing:

A theory is developed to predict the behaviour of a straight fibre when it is struck by a pin. The theory predicts that, if the pin speed exceeds a critical value for a given angle of impact, then the fibre will break immediately. Below this critical speed, the strain in the fibre passes through an initial peak and then peaks again as the free fibre end wraps around the pin. The theory can be used to predict the breakage of straight fibres in contact with high-speed pinss.

Y. Yan

Papers

The Behaviour of Fibres Struck by High-speed Pins. Part I: Theory