19—A STUDY OF NEEDLED FABRICS. PART VI: THE MEASUREMENT OF PUNCHING FORCE DURING NEEDLING

An account is given of an investigation in which a small needle board was fitted to the compression cage of an Instron Tensile Tester and used to measure the forces developed during the penetration of a web by needles. The punching speeds were much lower than those in a needling machine. The effects of web weight, type of fibre, fibre length and fineness, density, a reinforcing base fabric, and punching speed were studied.     

53—THE APPLICATION OF RADIO-TELEMETRY TO THE MEASUREMENT OF WEFT TENSION DURING THE WEAVING CYCLE

A set of criteria is presented for the continuous monitoring of weft tension under dynamic weaving conditions on a conventional shuttle loom. A radio-telemetry system is developed that is designed for the direct measurement of weft tension within the shuttle itself. Components of the system that are described include the transducer, transmitter and amplifier, power supply, switchgear, and aerial; the assembly of these components within the shuttle and the relay of weft-tension traces to an external receiver and recording device are also discussed. The performance characteristics of the monitoring system are studied, and a typical trace of weft tension is related to the action of the various weaving mechanisms on a conventional loom.     

33—A GRAVIMETRIC TECHNIQUE FOR DETERMINING THE MEAN FIBRE DIAMETER OF WOOL

A method is presented for determining the diameter of wool gravimetrically by using fibre snippets instead of full-length fibres. A quantity of the snippets is weighed and then counted with an electronic particle-size analyser (a Coulter Counter). The average length of snippets is obtained by measuring the length of a small random sample. The product of the average snippet length and the number of snippets present in the weighed sample provides an estimate of the total length of the weighed snippets. Hence their mass per unit length can be calculated, and, if the fibre density is known, the r.m.s. diameter can also be determined.

For continuous-filament nylon, the method gives excellent agreement with diameter values obtained by a conventional gravimetric technique. For combed wool, the snippet gravimetric diameter is always less than the projection-microscope diameter, corrected to r.m.s. Some of this difference is attributed to reentries in the wool-fibre surface.     

10—AN IMPROVED METHOD FOR THE PREPARATION OF WOOL FOR COLOUR MEASUREMENT

A simple, quick, and cheap method of preparing wool for colour measurement is based on the use of a heavy-duty blender as a vehicle for cleaning the wool. The method is applicable to greasy wool as well as to scoured wool.     

14—A CASTING TECHNIQUE FOR THE DETERMINATION OF BENDING STRAINS IN CARPET FIBRES

An account is given of experiments in which samples of carpet are held under a vertical load while immersed in an acrylic resin of low initial viscosity. After the resin has set, thin sections are cut perpendicular to the carpet backing, which enables measurement to be made of the bending strains in the carpet.

Bending strains as high as 0·1 are obtained, and the possible relevance of these values to those arising during normal carpet wear is discussed.     

18—A COMPUTER TECHNIQUE FOR ANALYSING THE CAUSE OF IRREGULAR PICKSPACING IN WOVEN FABRICS

A method for determining the cause of irregular pickspacing is described which is applicable in cases where there is a significant variation in weft count, particularly when there is no obvious correlation between weft count and pick-spacing. The method makes use of an electronic computer. The paper also draws attention to the significance of sample size in the experimental determination of weft count and pickspacing.     

21—THE MEASUREMENT OF FABRIC DRAPE

It is shown how the method of measuring fabric drape by supporting a circular specimen of fabric between smaller horizontal circular plates has been modified to allow a more sensitive test to be made on very stiff and very limp fabrics. The use of diverging light instead of parallel light is described, and the correction of the results for this change is calculated. A method of determining the drape coefficient by a paper-weighing method is also described.     

17—TRANSDUCERS FOR THE PRECISION MEASUREMENT OF WEFT-KNITTING FORCES. PART III: THE EXPERIMENTAL MEASUREMENT OF CAM AND YARN FORCES

Selected experimental results of dynamic forces recorded during knitting are reported. These were obtained by using a cam-force transducer designed to measure the dynamic forces between a latch-needle and the stitch and guard cams (see Part I) and a yarn-force transducer designed to measure the forces exerted upon the sinker and needle by the yarn during the formation of the knitted loop (see Part II).     

65—FIDIVAN—AN AUTOMATED SYSTEM FOR THE RAPID MEASUREMENT OF FIBRE DIAMETERS

A new system is described for measuring fibre diameter distributions rapidly and accurately, with minimum operator participation at any stage. It is based on the scanning of photographic images of aligned fibre snippets by a television camera connected to pulse-width-sorting circuitry, which gives an automatic print-out of the frequency distribution of fibre diameter. Results are given of measurements made with this system on IWTO standard tops that show very close agreement with accepted values.     

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.     

19—THE USE OF THICKNESS MEASUREMENTS DURING WEAR AS A BASIS FOR ESTIMATING CARPET WEAR-LIFE

A linear relation is shown to hold between the thickness of carpets and the logarithm of the number of treads sustained in a series of fifteen floor-wearing trials, with a mean correlation coefficient of 0.97. The 270 carpets examined varied widely both in constructional details and in pile-fibre types. The relation holds over virtually the whole wear-life of all these carpets and gives a sound basis for the estimation of the wear-life of any carpet from measurements made during the early stages of wear.     

2—THE QUANTITATIVE MEASUREMENT OF THE DEGREE OF WHITENESS OF WOOL TOPS

The aim of the work reported in this paper was to find a method for the instrumental determination of the degree of whiteness of wool tops that have not been treated with fluorescent brightening agents so that a classification similar to that provided by visual assessment can be made. The work is based on the visual classification performed by 54 experts on fourteen wool tops and on the colorimetric data obtained by the use of eight different instruments and applied to eleven formulae defining ways of expressing the degree of whiteness. The results allowed a selection to be made of the equipment and formulae that are adequate to achieve an analogous classification to that given by the experts.     

30—A NEW TEST FOR THE DETERMINATION OF THE MILLING PROPERTIES OF WOOL

A new milling test using felt balls is described. With the new laboratory milling machine that has been developed, it is possible to determine the milling properties of wools and blends in addition to the rate of felting (already measured by means of the Aachener Filztest). The nature and amount of mechanical energy on the specimen are similar to those in normal industrial milling machines. The test procedure may be varied. It is possible to use milling agents that foam with as low a wool/liquor ratio as 1:1. A comparative trial between the new milling test and the Aachener Filztest has brought to light some apparent discrepancies, which are discussed.     

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.     

24—THE MINIMIZATION OF FABRIC-CREASING DURING STORAGE

Investigations into the minimization of strain during storage, improvements in short-term crease recovery, and the effect of prolonged application of pressure are reported. Packing aids of various types and thicknesses are considered in terms of their efficiency in preventing crease formation or increasing the restoring force to aid in recovery.     

54—THE SIMULATION OF A MOISTURE-CONTROL SYSTEM FOR WOOL DRYERS

An account is given of an investigation into simulating the behaviour of a moisture-control system for suction-drum dryers handling loose wool. The dynamic characteristics of a typical plant without control were measured, and the characteristics of standard pneumatic-control elements were determined separately. These characteristics in transfer-function form yielded the parameters for an electrical-analog simulation, which showed that indirect control of the outgoing moisture in the wool was possible, since the hygrothermal environment in the dryer could be regulated satisfactorily. The control system could also cope with periodic fluctuations in the wool feed-rate, provided that these were of dissimilar period to that of the control loop itself.     

15—SOME ASPECTS OF THE MEASUREMENT OF COLOUR IN RAW WOOL

Factors influencing the measurement of CIE tristimulus co-ordinates for scoured wool, such as the test-specimen mass, the density, and the colour of the backing plate in the wool holder, are examined. Results obtained suggest that colour can be measured with high precision provided that the technique is standardized. Wools of greater fibre diameter are more sensitive to measurement conditions than fine wools, presumably owing to their higher mass-to-surface-area ratio.     

33—AN EXAMINATION OF A NEW METHOD FOR THE DETERMINATION OF THE VEGETABLE-MATTER CONTENT OF RAW WOOL

The Vegemat is a semi-automatic machine that carries out the procedures for vegetable-matter determination as described in the IWTO Specification IWTO–19–76(E). The examination of a Vegemat reported in this paper is based on a comparison between the Vegemat, the IWTO standard method performed manually, and results obtained by a commercial test house?. It is concluded that the Vegemat can be substituted for the manual method. If this substitution is made, a change in the correction factors (for the Vegemat) is necessary.