35—WITHDRAWAL FORCES IN THE PROCESSING OF WOOL SLIVERS: PART III: THE INFLUENCE OF PIN-DENSITY VARIATIONS

Measurements of the forces required to withdraw fibres from slivers inserted in combs of variable pin density are reported. In all cases, the withdrawal forces per fibre were well below the fibre breaking loads. Fibre breakage obtained in rectilinear combing is therefore ascribed to bad fibre alignment and fibre entanglement.     

33—WITHDRAWAL FORCES IN THE PROCESSING OF WOOL SLIVERS: PART I: THE DETERMINATION OF WITHDRAWAL FORCE

Apparatus is described by means of which the force necessary to withdraw a tuft of fibres from a sliver inserted in pins can be measured. An account is given of the use of this apparatus in investigations of withdrawal-force variations for different sliver weights and withdrawal speeds.     

44—THE INFLUENCE OF COTTON-SPINNING MACHINERY ON THE RANDOM IRREGULARITY OF SLIVERS AND YARNS PART II: EXPERIMENTAL INVESTIGATIONS

The experimental procedure is described, special attention being given to the influence of the measuring system. The results are given of measurements at the drawframe, speedframe, ring-spinning machine, and open-end rotor-spinning machine.     

43—THE INFLUENCE OF COTTON-SPINNING MACHINERY ON THE RANDOM IRREGULARITY OF SLIVERS AND YARNS PART I: THEORETICAL CONSIDERATIONS

The regularity of slivers and yarns is analysed by the mathematical and experimental method of system analysis. After the mathematical background has been sketched, appropriate parameters are defined, and a mathematical model—in the statistical sense—is developed. Special considerations concerning the effect of ‘doubling’ conclude the paper.     

31—INTERACTIONS BETWEEN ALKYLSULPHATES AND CATIONIC SHRINK-RESIST RESINS FOR WOOL PART II: THE INFLUENCE OF VARIOUS ALKYLSULPHATES ON THE SHRINKAGE OF KNITTED WOOL FABRICS

A study of the effect of the aggregates formed between Hercosett and alkylsulphates (C₈–C₁₄) in preventing the shrinkage of wool samples pre-treated with methylamine and hydrogen peroxide is reported. The amount of surfactant adsorbed on each pre-treated wool sample was estimated, and a mechanism by which the aggregate exhausts on the fibre is suggested.     

9—THE INFLUENCE OF RESISTANCE TO COMPRESSION ON THE PROCESSING PERFORMANCE OF SUPERFINE WOOLS PART I: TOPMAKING

Two series of experiments carried out to assess the rôole of resistance to compression in the topmaking performance of superfine wools are reported.

Wools of high resistance to compression gave lower scoured yields (by 4%) and top-and-noil yields (by 5%) and higher card wastes (by 2%) and noilages (by 3%) than wools of low resistance to compression. The tops produced from wools of high resistance to compression were shorter by 6 mm (Hauteur) than tops from wools of low resistance to compression. It is concluded that the differences are sufficiently large to be of commercial and technical significance.     

17—OBSERVATIONS ON THE CHARACTERISTICS OF AUSTRALIAN GREASY WOOL PART II: COLOUR IN MERINO FLEECE WOOLS

An analysis is presented of the colour characteristics of 1849 merino fleece wools in the greasy and clean states, the wools being classified according to the Australian Wool Corporation's type scheme. It is concluded that a subjective grading of greasy colour could satisfactorily replace style appraisal in price analyses and that merino fleece wools may be scoured out to clean colours that are acceptable for most routine end-uses. The advantages to the processor of routine colour measurement, which can be introduced at low cost, are pointed out.     

30—CAM-TO-NEEDLE IMPACT FORCES IN WEFT-KNITTING PART VII: THE INFLUENCE OF YARN TENSION AND MACHINE SPEED ON GUARD-CAM IMPACT

The results of experiments designed to investigate the effects of yarn-loop-drawing tension and machine speed upon the impact force between the needle and the guard cam are compared with theoretical values obtained by analytical procedures detailed in Part V, and the agreement is shown to be reasonably good. The impact force increases in direct proportion to the machine speed; increasing the yarn-loop-drawing tension delays the onset of the impact and reduces the magnitude of the impact force.     

36—THE AGEING OF WOOL. PART II: THE AGEING OF DISORGANIZED FIBRES

Experiments are described in which the stress-relaxation and recovery behaviour in bending is determined during ageing for wool fibres previously disorganized by a treatment in boiling water and is shown to be generalized linearly viscoelastic. This behaviour is also shown to parallel that of the stress-relaxation and ageing behaviour of native fibres in torsion, which is known to reflect the behaviour of the matrix component of structure. The results are shown to be consistent with a hypothesis proposed by Rigby et al. It is also demonstrated that the microfibrillar regions of the fibre contribute a constant spring-like component to the modulus, which does not stress-relax or age but is destroyed when fibres are disorganized by a treatment in boiling water. It seems certain that the major mechanical effects observed during ageing result directly from processes occurring in the matrix.     

72—THE EFFECT OF PROCESSING OILS ON THE SHRINKAGE OF HERCOSETT-TREATED KNITTED WOOL FABRIC

An account is given of an investigation of the shrinkage on washing of knitted wool fabrics produced from chlorine–Hercosett-treated tops to which a range of additives had been applied. It is shown that the range of effects of the various additives is very wide and that about half of those tested had no effect on the shrinkage rate. Four increased the shrinkage rate by a factor of more than ten and thus would be clearly unsuitable for industrial use. Additives of all the types studied (mineral-oil-based, synthetic lubricants, and softeners) were capable of causing a marked increase in the shrinkage rate, but other additives of each general type had no significant effect, so that it was not possible to make a clear distinction on the basis of a general classification. It is suggested that one component, or group of components, in the additives had affected the Hercosett resin, but no firm conclusions could be drawn about the exact mechanisms.     

12—RESIDUAL GREASE IN THE GILLING AND RECTILINEAR COMBING OF MERINO WOOL

In gilling and combing, there is an optimum level of residual grease, which gives a top with the lowest percentage noil and the highest mean fibre length. It is shown that, if the residual grease of the scoured wool could be held at approximately 0.8%, there would be little to be gained by the addition of a combing oil.     

30—THE INFLUENCE OF ORIGIN ON THE STRESS–STRAIN RELATIONS OF WOOL FIBRES

Stress–Strain data for wool fibres of different origin are presented, the tests having been made under different moisture conditions. Small differences exist between wool fibres from primary and secondary follicles from the same animal, the secondary being easier to stretch both initially and finally under wet conditions. However, the relative yield slope is markedly higher for secondary than for primary fibres. Differences exist between and within breeds in the initial modulus, the stress at 15% extension, and the slopes of the curves in the yield and post-yield regions.     

18—BEAT-UP FORCES IN WEAVING PART II

In this paper, the theory developed in a previous paper is extended to investigate the movement of picks in the cloth fell after and during beat-up. This is done for a weaving model in which the picks are represented by rigid incompressible cylindrical rods and the warp by incompressible cylindrical filaments of finite flexural rigidity. A friction law of the form F = cWⁿ is assumed to apply for movement of the weft relative lo the warp.

It is shown that picks slipping back in the warp after beat-up are responsible for very large increases in beat-up force and also cause discontinuities in the relation between beat-up force and pick-spacing.

The effect of varying several weaving parameters is discussed, and numerical results are obtained for a series of hypothetical cases. These show that a high warp tension before beat-up and a low fabric tension during beat-up minimize the increase in beat-up force that is due to pick movement.

They also show that a large shed angle at beat-up will reduce the pick movement, and the use of early shed-timing and a full-width temple is recommended for the weaving of tight fabrics.     

41—THE CONSTITUTION OF THE EPICUTICLE OF WOOL. PART III: THE SURVIVAL OF AMINO-ACID RESIDUES IN CHLORINE-WATER

An account is given of the determination of the extent to which saturated chlorine-water destroys individual amino-acid residues in insulin, lysozyme, α-keratose, and wool. Survival factors for a 5-min treatment are given for sixteen amino acids in each protein.     

38—THE INFLUENCE OF WIRE PROFILE ON THE QUALITY OF WOOL-TYPE CARDED WEBS. PART II: NON-CONVENTIONAL FLEXIBLE WIRE

This paper describes a series of carding experiments in which non-conventionally shaped flexible card teeth, with the leading edge of the tooth made narrower than the following edge, in contrast to conventionally shaped teeth, in which the leading edge is wider than the following edge, were used to assess the nep content and fibre breakage of webs made from 70s lamb's wool containing known amounts of cut woollen and worsted threads.

It is demonstrated, both theoretically and practically, that this new conception of card-wire profile will give less neppy webs for the same production rate than those produced by using conventionally shaped teeth. It is also shown that the new type of card wire leads to greater carding power, measured in terms of thread removal, with no increase in fibre breakage.     

30—OBSERVATIONS ON THE CHARACTERISTICS OF AUSTRALIAN GREASY WOOL PART III: COLOUR IN SUPERFINE MERINO WOOLS

An analysis of the colour of superfine wools drawn from forty flocks reveals that they are distinctly superior in this regard to common merino-fleece types before and after scouring. Correlations between the colour characteristics of greasy and scoured samples are extremely poor within and among flocks. Significant differences in the lightness and yellowness of superfine wools drawn from different districts are removed by scouring.     

11—THE DYNAMICS OF THE FALSE-TWIST PROCESS PART V: RESPONSE TO VARIATIONS IN FEEDSTOCK

The theory is extended to deal with the frequency response of texturing variables to variations, both actual and latent, in the feedstock linear density. Experimental measurements of the response made by using feedstock with controlled variation are compared with theoretical predictions, and conclusions are drawn about their relevance to textured-yarn quality.     

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.     

20—WOOL–POLYMER SYSTEMS: THE EFFECT OF ELASTOMERS ON THE WRINKLE-RECOVERY OF WOOL

The wrinkle-recovery of a wool fabric may be improved by coating the fibres with elastomeric polymers. It is shown that, of those polymers investigated, the most effective were found to be polyether–hexamethylene di-isocyanate polyurethanes and cross-linked silicones. Comparison of the wrinkling behaviour of fabrics and individual fibres indicates that the observed improvement in wrinkle-recovery was due to a coupling of the elastic-recovery forces of the polymer with those of the individual fibres, Inter-fibre bonding is thought to have an adverse effect on the wrinkle-recovery.     

31—CAM-TO-NEEDLE IMPACT FORCES IN WEFT-KNITTING PART VIII: THE EFFECT OF SOME KNITTING PARAMETERS ON GUARD-CAM IMPACT

The effects of certain knitting parameters on the impact force between the needle and the guard cam are described. It is found that increasing the stitch-cam incidence angle increases the guard-cam impact magnitude. The use of much steeper guard-cam angles tends to extend the duration of impact, as expected, but this is accompanied by higher impact-force magnitudes and more frequent needle-butt fractures. Progressively increasing the clearance between the cam and cylinder causes small but clearly discernible reductions in impact magnitude. Reducing the mass of the needle has a large effect in reducing the magnitude of impact but has little effect on its duration. Although no modifications to the shape of the needle butt conclusively reduce guard-cam impact conditions, they indirectly serve to spotlight the adverse effects of slight surface imperfections in the stitch cam. The heavy addition of lubricating oil to the cylinder tricks decreases the impact magnitude and causes the initial impact to occur at a higher velocity.