23—STUDIES ON THE NOBLE COMB. PART II: HOLDING POWER AND ITS PRACTICAL APPLICATION

An account is given of a study of the combing performance of the Noble comb in which the slivers emerging from the small and large circles were kept separate. Variations in the temperatures and pin densities of the circles produced changes in the holding power of the large circle of from 50 to 90% and in the ratio A/B of from 2 to 24. The holding power is linearly related to the production rate for a constant punch-sliver weight. By applying the correct holding power, an efficient separation of the short fine ‘down’ from the ‘beard’ hair in karakul wool was effected. Two combed slivers were produced simultaneously and differed in fineness by 9 μm. An appreciable reduction in percentage noil was brought about for karakul wool by reducing the pin density of the small circle.     

28—THE BENDING AND CREASING OF MULTICOMPONENT VISCOELASTIC FIBRE ASSEMBLIES. PART II: THE MECHANICS OF A TWO-DIMENSIONAL ASSEMBLY OF LONG STRAIGHT FIBRES OF DIFFERENT TYPES

A model two-dimensional assembly of long straight viscoelastic fibres of many different types arranged in various directions is analysed in terms of bending, creasing, and associated recovery behaviour. The fibres are assumed to be viscoelastic in both bending and torsion and subject to frictional restraints in both these modes of deformation. It is assumed that the model is relevant to the bending and creasing behaviour of woven and non-woven fabrics composed of fibres of one or more types.     

38—THE EFFECT OF FIBRE ARRANGEMENT ON THE INDICATION OF THE AIR-FLOW APPARATUS FOR WOOL FINENESS

The air-flow fineness apparatus, long used in the measurement of the fibre diameter of wool tops, is finding a rapidly growing application in the determination of the fineness of samples of loose wool or corings. It is known that the indication of the instrument is sensitive to the arrangement of fibres in the plug and that a calibration made by using wools in the form of tops cannot be expected to hold for the same wools in a different form.

This paper reports an investigation into the shift in instrument indication produced by subjecting tops to a variety of treatments: cutting, coring, hand- and machine-washing, and passage through the Shirley Analyser. The treatments were applied singly or in certain combinations. In all cases, the treatment produced an apparent increase in mean fibre diameter, i.e., increased air-permeability, the magnitude of the increase rising with mean diameter. The change in apparent diameter is considered to arise from an increase in pore-size distribution in the fibre mass, which is the result of disordering the fibre arrangement. Disordering can be caused by various treatments.

The effect of a steaming treatment on tops was somewhat similar to that produced by the other treatments already mentioned.

The magnitude of the apparent shift in diameter is tabulated for the important cases.     

22—STUDIES ON THE NOBLE COMB. PART I: THE INFLUENCE OF CIRCLE TEMPERATURES

The combing performance of the Noble comb is dependent on the withdrawal force of the ingoing slivers, the setting of the drawing-off rollers, the absolute temperatures of the small and large circles, and the quantity of ether-extractable matter present. The withdrawal force has the greatest effect on the production of minimum noil and is also a major factor in the selection of the optimum temperatures to be used at any given setting. A theory of fibre selection and fibre migration is presented in order to explain the experimental conditions characterizing minimum noil. It is shown that changes in mean fibre length sometimes conflicted with changes in percentage noil. Certain modifications to the comb were made in order that the combed slivers from the small and large circles could be separated.     

10—THE VARIABILITY OF YIELD AND FINENESS IN SOME CARDING AND INFERIOR TOPMAKING WOOLS

Studies of sampling variability relating to the measurement of yield and fineness of greasy wool have been published previously for auction lots of Australian wool in spinners-wool categories.

This paper describes similar studies for auction lots of carding and inferior topmaking wools. As expected, the between-bales and within-bales variability proved higher for these wools than for the spinners wools. Nevertheless, present sampling practices are expected to give acceptable precision.     

35—A STUDY OF NEEDLED FABRICS: PART VII: THE TRANSFER OF FIBRES THROUGH THE WEB BY NEEDLING

An account is given of a study of the extent to which fibres were pulled through the web during needling that was made by incorporating one layer of coloured fibres at various positions in a 50-layer web. The number of needle locations at which tracer fibres appeared and the number and length of fibres were determined.

Further studies of the occurrence of interlocking loops on the surface of a needled fabric are reported.     

43—THE AIR-FLOW DIAMETER OF WOOL TOPS: THE EFFECT OF COEFFICIENT OF VARIATION

Differences between the results obtained for the fineness of wool tops measured by air-flow and projection-microscope methods can arise because the coefficient of variation of the measured top is different from that of the tops used to calibrate the air-flow meter. The validity of some assumptions implicit in the air-flow calibration is examined and a correction table for precise use of the air-flow meter calculated. The corrections range from ?2% at 16 μm to zero at 36μm.     

6—DIMENSIONAL STABILITY OF PLAIN-KNITTED FABRICS

An account is given of a study of the dimensional changes of plain-knitted fabrics brought about by various relaxation treatments. A wide range of natural and synthetic-polymer fibres was encompassed.

It was found that, for synthetic-fibre fabrics, dry tumbling at elevated temperatures causes higher levels of relaxation shrinkage and larger changes in shape than static wet-relaxation treatments, whereas the opposite is true of fabrics produced from hydrophilic fibres. A wet treatment at an elevated temperature is proposed that brings about complete relaxation of all the fabrics investigated. It is only in this completely relaxed state that the loop shape is similar for all the fabrics investigated.     

10—THE USE OF FLUORESCENT STAINS FOR THE STUDY OF THE STRUCTURE OF ANIMAL FIBRES

An account is given of the use of fluorescence microscopy for the study of the structure of various animal fibres. Sections of wool, mohair, llama, cow-tail, and horse-tail fibres, which were either untreated or had had some chemical treatment, were stained with fluorescent stains; much more detail was shown by this technique than by other staining methods. Basic dyes (acridine orange, rhodamine B, rhodamine 3GO, and thioflavine T) stained the orthocortex and acid dyes (uranin and geranine G) the paracortex.     

13—AN AIR-FLOW METHOD FOR THE DETERMINATION OF THE FIBRE FINENESS OF JUTE AND MESTA

An account is given of air-flow experiments with paraIlel-fibre plugs of jute and mesta (kenaf). Over the working range of packing density of 0-4-0-6 g/cm³, the Kozeny equation was found to be approximately true. The dependence of κ on the porosity, ?, was examined and κ was found to be slightly low for white jute. The effect of combing on κ was small. Random-fibre plugs were unsuitable. On the basis of these observations, a simple direct-reading fibre-fineness tester with a constant-flow aspirator, suitable for use in Indian rural areas, has been developed for jute and mesta.