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The experimental analysis reported in this paper covers the dynamic response of drafting tension to forcing sinusoids of frequencies equivalent to wavelengths down to 0·3 x fibre length, which is considerably shorter than those attempted in earlier experimental analyses. It is shown by means of open-loop frequency-response analysis of drafting tension with front rollers controlled that the experimental response agrees with the analytical response only up to a certain limiting frequency, after which the amplitude-ratio magnification and increasing phase-lags exhibit a non-linear behaviour contrary to the predicted response. The openloop response with the back rollers controlled, however, agrees fairly well with the predicted response in both phase and gain characteristics. [ABSTRACT FROM AUTHOR]

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 yams; 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. [ABSTRACT FROM AUTHOR]

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The elastic resistance to bending of woven fabrics has previously been considered in terms of the existence in the yarns of rigid and elastic sections. The difficulties inherent in such a model and the noticeable differences between the predicted and experimental findings are examined in this paper. Two models of a plain-woven fabric in which the yarn cross-sections are incompressible are then analysed theoretically to obtain the predicted relationship between the applied couple and the curvature of the fabric. In the first model, the yarns are considered to be unset, i.e., if released from the fabric, they would be uncrimped, and in the second model they are considered to be completely set, i.e.. if released from the fabric, they would retain all their crimp. The predicted bending resistance does not agree with the behaviour of actual fabrics owing to the difficulty of defining the 'radius' of the yarn in the fabric, but many puzzling qualitative aspects of the bending behaviour of woven fabrics are, as a result of the analysis given, satisfactorily explained. [ABSTRACT FROM AUTHOR]

This paper is concerned with the evaluation of tool stresses in the orthogonal cutting process. Theory and elasticity methods are applied to determine these stresses within the elastic region. In this analysis the tool is considered as a wedge with the normal and frictional loading on the rake face. For general conditions of loading it has been found that the equivalent stresses are of the order of a hundred thousand pounds per square inch. It has also been found that tine equivalent stresses decrease with positive rake and increase with negative rake. [ABSTRACT FROM AUTHOR]

The elastic properties of several polyurethane yarns and a natural-rubber filament have been measured. Part 1 of the paper deals with the behaviour of the materials in the condition in which they were supplied. In Part 2, the properties of the materials after thermal treatments at various temperatures within the range 20-220°C are presented and discussed. Thermal treatment is shown to have a pronounced effect on the stress-strain behaviour of the synthetic yarns, measured relative to their set dimensions, and on the retractive stress at a given extension. The elastic recoveries of the yarns are improved, their breaking extensions increased, and their strengths slightly decreased after thermal treatment. Relative to the synthetic yarns, thermal treatment has only a small effect on the elastic properties of rubber. [ABSTRACT FROM AUTHOR]

The section of "Physical Testing and Quality Control," focuses on the strength, extensibility and flexibility of fabrics. Strength of a fabric is said to be a prerequisite characteristic for a fibre, as it helps in withstanding stresses. The section discusses standards issued by the British Standards Institution (BSI), and quick methods for testing elastic properties of high-stretch fabrics. It also refers to abrasion, pilling and problems with fabrics like snagging. Aesthetic properties of fabrics are also discussed.

An account is given of a study of the bending behaviour of three types of warp-knitted fabric with the aid of a cloth-bending-hysteresis tester. The stiffness, liveliness, and curling tendency of these fabrics, together with the effects of heat-setting on these properties, v/ere assessed, and the critical condition for rolling of the edge of a curly fabric is derived in a theoretical appendix. [ABSTRACT FROM AUTHOR]

Measurements of the bending elastic recovery of native and chemically modified cotton fibres are described; the results are used to estimate the degree of cross-linking in the treated fibres, and to predict the crease-recovery behaviour of fabrics made from the fibres. [ABSTRACT FROM AUTHOR]

1. The primary response contributing to an overall inhibition of root growth by IAA is a concentration dependent shortening of the period over which the roots elongate. 2. Deformation of root cell walls under constant, externally imposed load is composed of a plastic and an elastic component. These components are separable under the usual conditions of mechanical analysis. 3. Treatment of intact roots for one hour in the presence of concentrations of IAA that normally promote shoot growth and, therefore, inhibit root growth, results in formation of a concentration dependent, IAA-induced plasticity component, not observable in untreated roots. The change in deformability may be indicative of specific wall components either synthesized or altered in the presence of IAA. 4. Half-maximal plasticity is induced by ca. 5 × 10-7 M of IAA, a concentration comparable to that for Avena coleoptiles. 5. Deformability induced by IAA-treatment is transient, reaching a maximum after approximately one hour. 6. That increased deformability may be associated with increased root growth is indicated by measurements of fresh weight changes of excised root sections in the presence and absence of IAA. The IAA-induced increase in fresh weight is also transient with a maximum after approximately one hour. The overall effect of IAA-treatment of root sections -is to reduce growth. 7. Ionic regulation of cell wall deformability is found to be similar to that reported for stem tissues. Addition of divalent calcium ions results in cell wall stiffening, an effect which is reversed in the presence of an excess of monovalent sodium or potassium ions. [ABSTRACT FROM AUTHOR]