28—A STUDY OF THE OMISSION OF THE FIRST DRAWING PASSAGE IN JUTE-PROCESSING

The jute section of the textile industry normally uses three drawing passages for the production of hessian-type yarns. The work reported in this paper shows that the first drawing passage can be eliminated if adequate care is taken at the carding stages to produce sliver of good regularity, composed of longer and finer filaments. A device developed for producing thinner slivers to suit the second drawing frame without reducing the normal production of the finisher card is described.     

REVISITING “SUBSISTENCE CRISES”: THE CHARACTERISTICS OF DEMOGRAPHIC CRISES IN FRANCE IN THE FIRST HALF OF THE 19TH CENTURY 1

According to traditional accounts, France underwent a serious crisis in 1846. Although it has never really been proven, it is held that the crisis was due to an enormous deficit in agricultural production. The study of price fluctuations, where price increases are taken to be proportional to production deficits, has led to the characterization of this crisis as a subsistence crisis. Certain historians have even noted strong demographic repercussions, in particular an increase in mortality. This article proposes to reassess the importance of this crisis. It also re-examines the different economic and demographic variables and the relationships between them at a national and regional level. In fact, as far as the demographics are concerned, this crisis turned out to be of a low magnitude, particularly when compared to the crises resulting from cholera in the 1830s. This first observation leads to an assessment of the real importance of production deficits. Contrary to the famines of the end of the 17th century, this crisis, although labelled a subsistence crisis, is characterized by a rather low deficit in cereal production. Substitutes such as potatoes, buckwheat, maize, and imports limited the effect of the crisis. As far as price increases are concerned, they appear to be non-proportional to production deficits: the two variables are not correlated.     

41—AN APPLICATION OF MINI-COMPUTERS TO THE OPTIMIZATION OF THE OPEN-END-SPINNING PROCESS PART VIII: THE INFLUENCE OF THE INPUT-SILVER LINEAR DENSITY AND OF THE PARTIAL DRAFTS BETWEEN THE FEED AND THE ROTOR ON THE PROPERTIES OF COTTON YARNS: CONDITIONS AND RESULTS

The optimum conditions for the rotor-spinning of a given type of cotton, with the entry speed, total draft, and speed of production kept constant and the linear density of the input silver (and of the yarn produced) and the partial drafts between the feed and the rotor (feed–opening roller and opening roller–rotor) varied are established for yams of 26–40 tex.     

14—A STUDY OF NEEDLED FABRICS. PART IV: THE EFFECTS OF STRETCH,SHRINKAGE, AND REINFORCEMENT

Changes in fabric dimensions (length, width, and thickness) at the centre of a strip were measured both in continuous extension and in cycling tests. Values of Poisson's ratio, elastic recovery, and fabric density were calculated. The effect of pre-stretch on fabric properties was studied. The effects of shrinkage were investigated by examining the properties of fabrics produced from rayon blended with varying amounts of a polyester fibre that shrank in boiling water. Shrinkage caused considerable consolidation of fabrics. The effects of combining a woven base with a needled structure were studied on three laboratory-produced fabrics and several commercial samples.     

41—FOAM-BACKED TEXTILES: A NEW LAMINATING MACHINE AND THE PROPERTIES OF A RANGE OF LAMINATES

An account is given of a simple laboratory-type mangle, developed for laminating textile fabrics with foam material. It is shown that it is possible to obtain with this equipment laminates with negligible loss of thickness in the lamination process and with a bond of satisfactory strength. It is also shown that, when a few of the laminates were given a waterproof finish with polyurethane resin on the same equipment, a satisfactory degree of waterproofness was imparted to them with the simultaneous retention of some of their inherent water-vapour-transmitting capacity. The resistance of foam, fabrics, and laminates to the transmission of water vapour is evaluated in terms of the equivalent thickness of still air for purposes of comparison, and the measurement of the thermal-insulation values of the foam, fabrics, and laminates with a simplified hot-plate apparatus is described.     

17—QUANTITATIVE ANALYSES OF WEFT-KNITTED STRUCTURES PART IV: THE DETERMINATION OF THE MAGNITUDES OF B1, B2, AND B3 AND THE EXTENSION OF THE WORK TO GENERAL MULTI-COLOUR-JACQUARD STRUCTURES

The optimum design of experiment for the determination of the magnitudes of the component units of the weft-knitted jacquard structures, B ₁, B ₂, and B ₃, is discussed in detail. Some experimental results are reported. The prediction accuracy of using the technique of independent distinct units (IDU), by means of a suggested optimum experiment, proved to be very satisfactory in predicting the length of yarn of one design repeat of an arbitrary two-colour-jacquard example. The extension of the work to general multi-colour-jacquard structures is given.     

38—THE EFFECTS OF PLANAR CRIMP IN THE MEASUREMENT OF THE MECHANICAL PROPERTIES OF FIBRES,FILAMENTS, AND YARNS

A theoretical investigation of the tensile, flexural and torsional behaviour of crimped filaments has been made; the relationships describing the filament behaviour are presented in graphical and in analytical form, and are verified experimentally. Two results are of particular importance in routine textile testing: it is shown that the Young's modulus of staple fibres measured with a tensile-testing machine is not subject to significant error caused by crimp; and a new expression is proposed which enables the optimum tension for the routine yarn-crimp test to be calculated.     

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.