37—CAM-TO-NEEDLE IMPACT FORCES IN WEFT-KNITTING PART X: THE CHARACTERISTICS OF LATCH-NEEDLE BREAKAGES

The characteristics of the common causes of needle fracture at the hook and at the butt are examined, and it is shown that the fracture rate depends on the thickness of the needle material at the hook-bend and on the tightness of the needle in the trick.

Experiments in which the impact-measuring transducers developed in earlier parts of this series were used showed that the incidence of hook failure was directly related to the magnitude of the guard-cam impact. Tightly held needles usually result in failure as a result of stitch-cam impacts. A less common type of needle breakage, at a point near the latch pivot, was also investigated.

Various specially shaped needles were designed and tested in an attempt to reduce failure rates; these can help to reduce the incidence of fractures in the needle-head region, probably owing to a reduction in the amplitudes of the stress waves transmitted up the needle shank by the retarding effects of wedge-shaped cut-outs in the needle stem, but this improvement is accompanied by completely new types of breakage arising from stress concentrations caused by sudden changes of cross-sectional area.     

19—THE MEASUREMENT OF TORQUE IN CONTINUOUS-FILAMENT YARNS. PART II: THE EFFECT OF YARN TENSION

The yarn torque developed by the applied tension in the torsion-balance apparatus described in Part 1 of this series is calculated by using an expression derived in an earlier paper. Differences in shape of net-torque–twist curves are studied for nylon monofilaments and model plied yarns; these differences in shape are related to friction effects and to the mechanical properties of the constituent filaments. The torsional rigidity of the yarns is evaluated from the initial slope of the torque–twist curves for a series of nylon monofilaments; the torsional rigidity and torsional modulus are also calculated from the load–extension curve of a closely wound helical spring by employing the classical theory of elasticity.     

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.     

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.     

32—A SIMPLIFIED METHOD OF DETERMINING THE LENGTH AND FINENESS CHARACTERISTICS OF FIBRES IN JUTE SLIVERS AND YARNS

The normal method of studying the length and fineness characteristics of fibres in jute slivers and yarns involves classifying the fibres in a sample into a suitable number of length groups and determination of the frequency and linear density of fibres in all the length groups. The simplified method described in this paper requires evaluation of the cumulative frequency and linear density of fibres of one particular length only, and is hence less time-consuming than the normal method. Graphical relations and tables are provided with the simplified method to reduce the computation time, which is considerable with the normal method. The data obtained on several yarn samples of different qualities by the normal method of testing are used to show the agreement between the results arrived at by the two methods. A procedure for carrying out the tests required in the simplified method is also suggested.     

11—OBSERVATIONS ON THE CHARACTERISTICS OF AUSTRALIAN GREASY WOOL PART I: STAPLE LENGTH IN MERINO FLEECE WOOLS

The average staple length of merino fleece wool is 84 mm. Subjective classification of diameter–style groupings from one selling centre into ‘long’, ‘medium’, and ‘short’ produces differences of 7–8 mm between adjacent length categories. Sale lots within these length categories vary by ± 14 mm (95% confidence interval), so there is considerable overlap even between ‘long’ and ‘short’ wools. Individual staples within a sale lot vary by ± 25 mm about the mean (95% confidence interval). These estimates vary significantly with diameter and style category and among selling centres.     

19—THE DESIGN AND DYNAMICS OF NON-LINEAR CAMS FOR USE IN HIGH-SPEED WEFT-KNITTING MACHINES PART I: THE THEORETICAL DYNAMICS OF NON-LINEAR CAMS

The dynamics of a latch needle travelling with constant horizontal velocity through a symmetrical non-linear knitting cam are analysed in detail. Equations to calculate R and S—the reaction forces between the needle butt and cam face and needle butt and cylinder wall, respectively— are set up for any possible needle-cam contact and the boundary constraints described that determine that contact. A hypothetical knitting situation is examined with the aid of a simple harmonic cam shape.     

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.     

23—DEPOSITS IN THE ROTOR GROOVE IN OPEN-END SPINNING PART I: THE INITIATION AND DEVELOPMENT OF ROTOR DEPOSITS

Observations are reported that show the rapid formation of a film over the rotor surface, which is soon followed by the appearance of small localized deposits in the groove that act as nuclei for further deposition until a complete ring of deposits forms. When the ring reaches a certain thickness, spinning becomes impracticable, owing to frequent end-breakages accompanied by difficulties in picking-up. The time to reach that stage is regarded as the ‘maximum spinning time’. Small deposits may be displaced in the groove by the action of the yarn.     

27—THE RôLE OF WATER IN THE SETTING OF WOOL: A STUDY OF SETTING AT TEMPERATURES ABOVE 100°C: PART II: FABRIC PROPERTIES

An account is given of a study of the changes in fabric properties caused by setting with steam in autoclaves. Dimensional stability, shear angles, thickness, and breaking strength were measured, and the influence of variations in setting conditions, such as humidity, temperature, time, pH, and mechanical pressure, was investigated. The controls necessary for eliminating end-to-end effects in whole pieces are discussed.     

63—SOME ASPECTS OF WORSTED-YARN STRUCTURE. PART IV: THE APPLICATION OF FOURIER ANALYSIS TO THE STUDY OF SINGLE-FIBRE CONFIGURATIONS IN A SERIES OF WORSTED YARNS

A study is reported of some aspects of the configuration of single wool fibres in some worsted yarns. By applying the technique of finite Fourier analysis to traces of fibres obtained by utilizing the dyed-tracer-fibre technique, it is demonstrated that the paths of single fibres in worsted yarns can be broken down into a wide range of periodicities, some of which are related to spinning parameters and others to fibre characteristics.     

38—CAM-TO-NEEDLE IMPACT FORCES IN WEFT-KNITTING PART XI: THE MEASUREMENT OF IMPACT-INDUCED STRAINS IN LATCH NEEDLES

Experiments are described in which strains in the needle shank immediately following impacts between the cams and the weft-knitting elements were measured by micro-miniature strain gauges bonded to the needle shank and hook. These experiments showed a longitudinal component of strain after the guard-cam impact and a lateral (bending) component of strain after the stitch-cam impact. Measurements on the needle hook revealed many stress reversals subsequent to the impacts.     

“ETHNIC FOODS” AND REGIONAL IDENTITY: THE HEZHA RESTAURANTS IN ENSHI

This article is a study of the local food culture and identity politics in Enshi Prefecture, China. It examines customary foods of Enshi people, as sold in the Hezha restaurants, and the relations between these foods and the Tujia ethnic identity that the local elite has constructed. The analysis suggests that these Hezha foods reflect the highly unified aspect of the local regional identity, which cannot be classified into, or analyzed in terms of, the officially recognized ethnic categories.     

11—A STUDY OF YARN TORQUE AND ITS DEPENDENCE ON THE DISTRIBUTION OF FIBRE TENSILE STRESS IN THE YARN PART I: THEORETICAL ANALYSIS

The torque generated during yarn-twisting is considered to have three components, due, respectively, to fibre torsion, fibre-bending, and the internal fibre tensile and compressive stresses within the yarn. An analysis of the yarn torque generated by fibre torsion will be given in a later paper, and the component due to fibre-bending has been evaluated by other authors. It is proposed that the nature of the fibre tensile-stress distribution within a yarn is likely to be the most influential factor governing the magnitude of yarn torque. The distribution of stress, as a function of the fibre position in the yarn, depends largely on the facility with which fibres can migrate throughout the yarn cross-section. In this paper, two limiting forms of fibre geometry are considered: no migration, and complete fibre equivalence as a direct consequence of migration. For each case, the fibre-stress distribution is analysed, and the component of yarn torque due to these stresses is derived.     

30—PERMANENT-PRESS EFFECTS IN WOOL. PART XIV: THE RETENTION OF SET IN POLYMER-TREATED WOOL UNDER VARIOUS WASHING CONDITIONS

The rate of loss of set in wool fabric during machine-washing increases with the temperature of the wash liquor. The application of a pre-formed polymer to the set wool retards loss of set, especially at lower washing temperatures. In addition, under commonly used laundering conditions, set is lost at a faster rate in machines with a vigorous washing action than in machines with a mild action. It is believed that the higher average level of strain imposed on the samples by the more vigorous washing actions leads to an increase in the rate of stress relaxation in the fibres.     

11—PERMANENT-PRESS EFFECTS IN WOOL. PART XII: THE MECHANISM OF STABILIZATION OF SET TO MACHINE-WASHING BY PROLONGED STEAMING

Prolonged steaming of wool in the presence of reducing agents, alkalies, or water alone produces set that is stable to machine-washing by lowering the thiol content of the wool and thus inhibiting thiol–disulphide interchange rather than by secondary effects, such as cross-linking or denaturation.     

12—AN ENERGY METHOD FOR CALCULATIONS IN FABRIC MECHANICS PART II: EXAMPLES OF APPLICATION OF THE METHOD TO WOVEN FABRICS

In the preceding paper, an energy method for performing calculations in fabric mechanics, together with appropriate computational techniques, was described. The present paper contains examples of applications of this method to woven fabrics, particularly to various models of plainweave fabric subject to tension, but also briefly to fabric-bending and to other weaves.