34—WITHDRAWAL FORCES IN THE PROCESSING OF WOOL SLIVERS: PART II: THE INFLUENCE OF VARIATIONS IN GILLING ON THE WITHDRAWAL FORCE

An account is given of the use of withdrawal-force measurements to determine the extent of fibre alignment in slivers. It is shown that a direct relation between withdrawal force and percentage noil exists. Several variations in the preparation of slivers were investigated, namely, the number of gillings, the draft during gilling, and the direction of feed.     

56—THE WRINKLING BEHAVIOUR OF WOOL FABRICS: THE EFFECT OF THE STRUCTURE OF FORMALDEHYDE CONDENSATION POLYMERS ON THE STABILIZATION OF ANNEALED WOOL

An investigation is reported of the use of formaldehyde condensation polymers of aromatic amines, heterocyclic amines, and phenols to stabilize the improved wrinkle-recovery of annealed wool. These polymers were formed in situ during the annealing process.

The most effective polymer networks were those obtained from the reaction of formaldehyde with multifunctional compounds such as (i) 2,4,6-triaminopyrimidine, (ii) 2,6-diaminopyridine, (iii) 3,5-diamino-1,2,4-triazole, (iv) 1,3,5-trihydroxybenzene, (v) 1,3-dihydroxybenzene, and (vi) 2,4,6-triamino-s-triazine.     

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.     

25—INCREASING THE RATES OF FABRIC PRODUCTION OF WEFT-KNITTING MACHINERY: PART III: MEASUREMENT OF THE NEEDLE FORCES

When information is required about the forces acting on the needles in different cam systems, it is clearly more desirable to measure these forces directly than to measure the over-all machine torque.

This paper describes a method for measuring the needle forces directly, and an examination is made of some of the information obtained from the force-measuring device used.     

10—THE WRINKLING BEHAVIOUR OF WOOL FABRICS: THE EFFECT OF ANNEALING AND CROSS-LINKING

An investigation is described in which various polyfunctional compounds were applied to wool in attempts to stabilize the temporary improvements in wrinkle-recovery brought about by ‘annealing’. Several reactive systems involving formaldehyde were found to produce the desired permanently improved wrinkle-recovery.     

33—THE STRENGTH OF COTTON FIBRES AND THE DEGREE OF DEVELOPMENT OF THE SECONDARY WALL

A comparative analysis of two methods of determination of the maturity of cotton fibre is reported. One consisted in comparing fibres with reference drawings and the other in using the polarizing microscope. The relationship between the degree of development of the secondary wall determined by these methods and the strength of cotton as one of its most important physical properties was also taken into consideration.

The degree of correlation between the methods discussed and between the results obtained with them and the breaking load was found.

It was also ascertained that the degree of maturity was not the same throughout the length of the fibre. It increased from the base to the tip of the fibre.     

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.     

34—A CONTRIBUTION TO THE STUDY OF THE INFLUENCE OF THE DESIGN OF THE YARN-WITHDRAWAL TUBE ON THE DIAMETER AND HAIRINESS OF OPEN-END-SPUN ACRYLIC-FIBRE YARNS

An investigation is reported in which factorial experiments were conducted to study the influence of the design of the yarn-withdrawal tube (or nozzle) on the diameter and hairiness of open-end-spun acrylic-fibre yarns. Three nozzle types, combined with three values of yarn linear density and five values of twist multiplier, were studied for four different (but equal-diameter) rotor types. lt is shown that the nozzle type has very little influence on yarn diameter but has a more significant effect on yarn-hairiness parameters. As the nozzle diameter increases, yarn hairiness also tends to increase, but, when the nozzle is grooved, an interaction is produced between yarn friction and the false twist generated that leads to a yarn that is less hairy when tested on the Digital ITQT Hairiness Meter. The principle of measurement of the apparatus used can lead to different results and trends when applied to this problem.     

67—THE INFLUENCE OF WIRE PROFILE ON THE QUALITY OF WOOL-TYPE CARDED WEBS. PART III: THE ASSESSMENT OF CARD-WIRE SHARPNESS

This paper is concerned with a technique for assessing different degrees of sharpness between flexible card-wire teeth. An Instron Tensile Tester was used to measure the force required to pull strips of granular-faced material over card teeth that differed in both sharpness and density, both ‘with’ and ‘against’ the wire points. Variants introduced included the load applied by the granular material to the teeth and the grit size of the granular material.

It is shown, on the basis of experiments on five different densities of card clothing, each ground to three different degrees of sharpness, that these differences can be quantitatively detected when they are measured against the wire points and that they are in complete agreement with the subjective assessments of wire sharpness.

It seems possible that the principles enunciated in this paper may be used to devise an instrument for detecting differences in wire sharpness.     

39—THE DETERMINATION OF THE LATERAL-COMPRESSION MODULUS OF FIBRES

An account is given of the measurement of the transverse deformation of fibres under various loads acting normal to the fibre longitudinal axis by a technique in which fibres are interleaved between glass plates in a vertical stack. Graphs of transverse load against compression are plotted for nylon, acrylic, and viscose rayon fibres under both air-dry and wet conditions.

An expression for the transverse deformation in terms of the applied load is proposed and used to calculate the lateral-compression moduli of the various fibres. The results show that, laterally, nylon fibres in both wet and dry states have the highest modulus and that acrylic fibres appear to be least affected by immersion in water. Viscose rayon fibres are most affected by water and experience a reduction in modulus by a factor of about 20.     

33—THE DYNAMICS OF THE FALSE-TWIST PROCESS PART I: THE PROCESS SURVEYED

The changes experienced by a yarn during its progress through the falst-twist-texturing system are examined. The relations involved, between twist, tension, and torque, and the process parameters, are shown to be those of a feedback system, and the dynamic operation of the process is considered, in a general way, by using this concept.     

23—A THEORETICAL ANALYSIS AND EXPERIMENTAL STUDY OF THE PLAIN SQUARE WEAVE: PART II: THE ASSESSMENT OF THE LENGTH OF YERN PER UNIT CELL IN THE WOVEN STRUCTURE

Techniques for obtaining an accurate assessment of the length of yarn in a unit cell of a woven structure are given. The effect of sett, cover factor, and state of relaxation are particularly examined with these techniques. The stress–strain relations of yarns at low loads, comparable with those for woven yarns, are demonstrated.     

30—AN APPLICATION OF MINI-COMPUTERS TO THE OPTIMIZATION OF THE OPEN-END-SPINNING PROCESS PART V: THE EFFECT OF SUPPRESSING ONE DRAWFRAME PASSAGE IN THE OPEN-END PROCESSING OF ACRYLIC FIBRES

The optimization of the opening-roller speed in open-end spinning is studied for a given type of fibre, and the effect on the yarn properties of suppressing one drawframe passage is considered. The experiments carried out with acrylic fibre show the existence of an optimum zone for the speed of the opening roller and also indicate that the suppression of a drawframe passage in the normal industrial process leads to a drop in yarn quality that principally affects the regularity and influences both the tenacity and the elongation at break of the yarn to a less extent.     

60—AN INVESTIGATION OF THE TAPER OF COTTON FIBRES. PART I: THE EXPERIMENTAL DETERMINATION OF TAPER

In this study, an attempt is made to define and estimate cotton fibre-end taper. On the basis of fibre profiles obtained on single fibres and bundles, a few concepts for estimating taper were considered, namely, (i) the variability of the ribbon width or linear density of the fibre along its length, (ii) the length of the thinner part of the fibre with respect to an arbitrarily chosen value, (iii) the angular width of the fibre at its tip, and (iv) the relative linear densities at the two ends with respect to the mid-portion.

A critical analysis of the data obtained on seven cottons of varying fibre properties indicates that the taper parameters are dependent on the length group of the fibres but that the taper estimated on fibres belonging to the modal length can be used to characterize a cotton.     

18—AN APPLICATION OF MINI-COMPUTERS TO THE OPTIMIZATION OF THE OPEN-END-SPINNING PROCESS PART IV: THE INFLUENCE OF WINDING TENSION ON YARN PROPERTIES

The winding tension and package mass can affect the characteristics of rotor-spun yarns. The properties most affected are the elongation at break and yarn imperfections, particularly thick places, so that the yarn irregularity is also affected. Increases in winding tension above a given value reduce the yarn quality quite independently of the package mass. When the winding tension is low, however, this mass exerts some influence, the yarn quality deteriorating as the package mass increases.     

29—THE MEASUREMENT OF THE LENGTH-TO-DIAMETER RATIO OF SHORT SNIPPETS OF WOOL

An expression relating the length-to-diameter ratio of circular cylinders to the over-all volume that a random assembly of a given quantity of cylinders takes up is derived for variable length and variable diameter of a snippet. The results of experimental determinations are shown to correlate well with these theoretical considerations. The formula was checked for wool fibres with diameters in the range 20–30 μm and for snippet lengths from 0.2 to 2 mm.     

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.     

17—THE PREDICTION OF THE COMMERCIAL CARBONIZING YIELD OF WOOL

An investigation is reported in which the core-test yield was compared with the achieved mill yield for 90 commercial batches of Australian wool. Eight Australian mills participated in the trial. It was found that the wool base of the greasy wool (B _g%) was directly proportional to the achieved mill yield. The carbonizing loss, which was on the average 3.05% (on an oven-dry basis), was negatively correlated with the vegetable-matter base of the greasy wool (VMB _g%. The most precise prediction of the achieved mill yield was given by the equation:

ECCY% = 1.1972 B _g% + 0.1616 VMB _g% ? 5.12,

where ECCY% is the estimated commercial carbonizing yield. For the 90 batches in the trial, the standard error of the prediction was 1.95%.     

28—THE SPECIFIC HEAT OF WOOL CONTAINING AN ADDITIVE AND THE HEAT OF FUSION OF THE ABSORBED WATER

Specific-heat values are presented, in the temperature range from ?70 to 100°C, for a modified wool at various water contents. The modification was analogous to a dyeing process and involved the uptake of 14% of an additive by the wool. As for untreated wool, an endothermic peak resulting from the fusion of absorbed water was found in the range from ?30 to 0°C. The absorbed water exhibits a sub-division into freezable and non-freezable fractions. Heats of fusion of freezable absorbed water are given and compared with corresponding results for untreated wool. The integral heat of fusion at saturation water content is much less for treated than for untreated wool, as is the amount of freezable water. It appears that the treatment causes the exclusion of a considerable quantity of loosely held water. This is in accord with the concept, derived from Flory–Huggins solution theory, that one effect of the additive is to swell the wool fibres and thereby cause a greater resistance to further swelling at a given water content.     

28—SELFIL SPINNING: THE EFFECT OF PHASING BETWEEN THE TWO FILAMENTS

The principles underlying Selfil spinning are outlined as an introduction to the effect of filament-phasing on various yarn properties. Phasing of 110° between the filaments gives maximum strength, high torque stability, high filament cover of the staple-fibre core, and short regions of zero filament wrap.