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Tensile properties are important to wool fiber because of their direct effect on the mechanical properties of wool yarns and fabrics. Many studies have been conducted to understand these fiber properties of conventional merino (CM) wool, while those of Australian Soft Rolling Skin (SRS) wool are not yet clear. In this work, SRS wool was compared with CM wool to find out the difference in these two types of wool and explore the underlying reasons for this difference. Experimental results indicate that there is no statistically significant difference in the breaking strength between SRS and CM wool, while the average breaking elongation is slightly higher for SRS wool (37%) than CM wool (34%). SRS wool (2.38 GPa) has a lower modulus than CM wool (2.53 GPa). The lower coefficient of variation of mean fiber diameter (MFD) along fiber length (fiber irregularity) is likely responsible for the higher breaking elongation for SRS wool. These findings add new knowledge to the literature on SRS wool and may have implications for the processing performance of SRS wool. [ABSTRACT FROM AUTHOR]

Keel bone fractures are a serious animal welfare problem in laying hens. The aim of the current study was to assess the influence of egg production, oestradiol-17ß, and selection for high laying performance on bone quality. Hens of two layer lines differing in laying performance (WLA: 320 eggs per year, G11: 200 eggs per year) were allocated to four treatment groups. Group S received a deslorelin acetate implant that suppressed egg production. Group E received an implant with the sexual steroid oestradiol-17ß. Group SE received both implants and group C did not receive any implant. In the 63rd week of age, composition and characteristics of the tibiotarsi were assessed using histological analysis, three-point bending test, thermogravimetric analysis, infrared spectroscopy, and two-dimensional X-ray diffraction, respectively. Non-egg-laying hens showed a higher total bone area and a higher relative amount of cortical bone compared to egg-laying hens. Hens of layer line G11 showed a higher relative amount of medullary bone and a higher degree of mineralization of the cortical bone compared to hens of layer line WLA. These differences in bone composition may explain different susceptibility to keel bone fractures in non-egg-laying compared to egg-laying hens as well as in hens of layer lines differing in laying performance. The effect of exogenous oestradiol-17ß on bone parameters varied between the layer lines indicating a genetic influence on bone physiology and the way it can be modulated by hormone substitution. [ABSTRACT FROM AUTHOR]

In the manuscript, the liquid-phase deposition technique was used to successfully deposit an Al2O3 ceramic coating on the quartz fiber. The thickness of the coating was not uniform. The thickest part of the coating can reach to 1159 nm. The main coating formed is Al2O3, but there are still hydrous Al(OH)3. With the extension of the deposition time, the micro-morphology of the coating changed from nano-scale clusters to dense flakes. The coating had an amorphous structure. In this case, the coating effectively improved the mechanical properties of the quartz fiber at high temperatures, and the breaking load of the fiber increased with the extension of the deposition time. After high temperature annealing, the breaking load of the coated fiber deposited for 6 h was 126.1 N, compared to 50.3 N of the blank fiber. The protection mechanism of Al2O3 coating was studied from the aspect of microstructure. By observing the surface morphologies of blank fiber and coated fiber after high temperature annealing. It was found that the presence of the coating hindered the damage of the fiber surface by high temperature, and the defects on the fiber surface were reduced, so the mechanical properties were effectively improved. [ABSTRACT FROM AUTHOR]

Allogeneic cortical bone plates (CP) are used for alveolar ridge augmentation. Since CP are freeze-dried and dehydrated during processing, the breaking strength (BS) and the flexibility (FX) are reduced, resulting in a relevant risk for plate fractures during insertion. The aim of this study was to evaluate the influence of rehydration time on the biomechanical properties (BS & FX) of CP in-vitro and in vivo. 40 CP were randomly divided into four experimental groups. (A) untreated control (n = 10), rehydration for 10 (B), 30 (C) and 60 (D) minutes in 0.9% saline solution (n = 10 each). BS [Newton, N] and FX [mm] (force till fracture and distance of deflection to the breaking point) were analyzed. Besides, architectural features of all CP groups were visualized and examined by scanning electron microscopy (SEM). In addition, the frequency of CP fractures of rehydrated- vs. non-rehydrated CP was retrospectively analyzed in 6 patients. Compared to the control group, significantly increased BS and FX were demonstrated after 10, 30 and 60 minutes of rehydration (p each ≤ 0.035). After a rehydration time of 10 minutes, no additional increase of BS and FX was seen when compared to30 and 60 minutes (p each = 1.0). SEM scans demonstrated that the CP fracture characteristics were influenced by the different rehydration protocols. The frequency of CP fractures was reduced in patients by CP rehydration. The biomechanical properties of CP can be significantly improved by 10 min of rehydration, resulting in an increased BS and FX, that might be clinically relevant. [ABSTRACT FROM AUTHOR]

Performance of parachute continuously degrades due to opening shock and dynamic pressure acting on its various components after opening. During repeated use of parachute, degradation in tensile strength of canopy fabric plays an important role. Measurement of probability of successful operation of parachute in repeated use and under impact loading is possible through reliability analysis of its seam joints. Present study mainly concerned with the reliability analysis of the performance of square plain parachute canopy joined in parallel at different bias angle. The impact loading of the specimen degrades its tensile property and the extent of loss depends on its bias angle of stitching. However, the deterioration of performance in terms of tensile strength is more as compared to breaking elongation. Without subjecting any impact, specimen stitched at 0° and 45° have almost same breaking strength. However, impact loading degrades the tensile property of specimen with 45° bias angle to a greater extent as compare to specimen with 0° bias angle. As regards breaking elongation of specimen, the specimen stitched at 45° bias angles always exhibits highest value (even after impact loading) than the specimen stitched at other bias angles. The reliability analysis of seam joints shows that the specimen stitched at 0° bias angle is most reliable among other angles of stitching in terms of maintaining tensile strength for longer impact cycle. [ABSTRACT FROM AUTHOR]

Background: Which suture material is optimal for pancreaticojejunostomy (PJ) anastomosis is a matter of debate with contradictory results. The aim of the present in vitro study was to determine the effects of pancreatic juice, bile, and their mixture on different suture materials in terms of breaking strength and disintegration.Material and Methods: Four suture materials, silk, polyglactin 910, polydioxanone, and polypropylene, were tested in pancreatic juice, bile, and their mixture. Determination of breaking strength and disintegration under electron microscope for each suture material was done on days 0, 3, 6, and 10.Results: The breaking strength of polyglactin 910 and silk was significantly higher than polypropylene and polydioxanone (p< .05). Polyglactin 910 significantly lost its breaking strength with time in pancreatic juice, bile, and their mixture (p< .001). The breaking strength of each type of suture did not significantly alter in pancreatic juice, bile, and their mixture at the baseline measurement and at the end of the experiment (p> .05). No obvious disintegration has been observed under electron microscope in the architecture and appearance of suture materials after days of exposure to pancreatic juice, bile, and their mixture.Conclusions: None of the suture materials was disintegrated on exposure to pancreatic juice, bile, and their mixture. Polyglactin 910 has the highest breaking strength and significantly loses its strength throughout the experiment but still remains higher than other suture materials. Polypropylene, polydioxanone, and silk showed less variation across the incubation period. [ABSTRACT FROM AUTHOR]

The bone is a mineral reserve for metabolic requirements and eggshell formation as well as providing support to the bodies of birds. Bone weakness in laying hens has caused many problems such as bone deformation, osteoporosis, cage layer fatigue and fractures. These problems result in economic losses and are detrimental to animal welfare. Breaking strength is a good indicator of the health and strength of bone and an increase in breaking strength in laying hens would be important to decrease economic losses and improve the welfare of animals. One of the main factors affecting bone breaking strength is nutrition, as it is closely related to dietary calcium, phosphorus, vitamin D and particle size of the calcium source, particularly when the dietary calcium is insufficient. It has been accepted that the composition of the diet, trace elements, especially boron, vitamins, and feed additives play important roles in maintaining bone health and improving the breaking strength of bone in laying hens. This article reviews the results of studies in laying hens wherein the effect of nutrition on the breaking strength of bone were examined. [ABSTRACT FROM PUBLISHER]

Powders intended for the use in dry powder inhalers have to fulfill specific product properties, which must be closely controlled in order to ensure reproducible and efficient dosing. Spray drying is an ideal technique for the preparation of such powders for several reasons. The aim of this work was to investigate the influence of spray-drying process parameters on relevant product properties, namely, surface topography, size, breaking strength, and polymorphism of mannitol carrier particles intended for the use in dry powder inhalers. In order to address this question, a full-factorial design with four factors at two levels was used. The four factors were feed concentration (10 and 20% [w/w]), gas heater temperature (170 and 190°C), feed rate (10 and 20 L/h), and atomizer rotation speed (6,300 and 8,100 rpm). The liquid spray was carefully analyzed to better understand the dependence of the particle size of the final product on the former droplet size. High gas heater temperatures and low feed rates, corresponding to high outlet temperatures of the dryer (96–98°C), led to smoother particles with surfaces consisting of smaller crystals compared to those achieved at low outlet temperatures (74–75°C), due to lower gas heater temperatures and higher feed rates. A high solution concentration of the feed also resulted in the formation of comparably rougher surfaces than a low feed concentration. Spray-dried particles showed a volume-weighted mean particle size of 71.4–90.0 µm and narrow particle size distributions. The mean particle size was influenced by the atomizer rotation speed and feed concentration. Higher rotation speeds and lower feed concentrations resulted in smaller particles. Breaking strength of the dried particles was significantly influenced by gas heater temperature and feed rate. High gas heater temperatures increased the breaking strength, whereas high feed rates decreased it. No influence of the process parameters on the polymorphism was observed. All products were crystalline, consisting of at least 96.9% of mannitol crystal modification I. [ABSTRACT FROM AUTHOR]

This paper focuses on the evaluation of wet pneumatic spliced elastic yarn performance using the fuzzy logic theory. Referring to Altinoz's study (Altinoz & Winchester, 2001), fuzzy logic method allows a new level of flexibility over traditional mathematical methods in defining and evaluating constraints. The application of fuzzy rules and fuzzy memberships is discussed and investigated. Using the suitable parameters and optimized splicing conditions such as yarn count, length of splice and duration of water joining, the results show that triangular membership gives better fitting of experimental results. Compared to the experimental properties, theoretical performances of the wet splice can be predicted in the desired field of interest. Our results also indicate that the splice performance remains influenced especially by the elastic yarn count and the splice length as well. In this work, the expert's opinions using our fuzzy logic model were formalized with precision. Compared with regression model, the fuzzy model gives a more accurate prediction than the regression model. [ABSTRACT FROM AUTHOR]

Blends of durum clear flour, partially defatted hazelnut flour (PDHF) and rice grit were extruded through a single-screw extruder to form expanded products. The extrudates were analyzed for physical properties, namely radial expansion ratio, colour, and instrumental texture. The radial expansion ratios measured for all the extruded samples ranged between 3-4.5. Breaking strengths of the extrudates varied between 0.387-0.854 N mm-2. The measured values of the colour parameters of extruded blends varied in the range from 48.72-72.24 for lightness (L), 1.95-5.79 for redness (a), and 13.79-15.26 for yellowness (b). [ABSTRACT FROM AUTHOR]

Carrot slices were subjected to the following four different pretreatments prior to vacuum frying: (1) blanching, (2) blanching and air drying, (3) blanching and osmotic dehydration, (4) blanching, osmotic dehydration, followed by freezing. The effects of these pretreatments on the physicochemical properties and fat distribution in vacuum-fried carrot chips were also investigated. There were significant differences in the total yield, amounts of carotenes, vitamin C, and the color values of carrot chips following different pretreatments (P < 0.05). Pretreatment significantly affected the water content, fat content, and water activity of carrot chips (P < 0.05), while there were no significant differences in the breaking force of carrot chips treated with different pretreatments (P > 0.05). Spearman correlation analysis showed a high positive correlation between the fat content of carrot chips and the initial water content of carrot slices. The fat distribution pattern depended on the initial water content and the structure of the material left by water evaporation. [ABSTRACT FROM AUTHOR]

Erythropoietin exerts hematopoietic effects by stimulating proliferation of early erythroid precursors. Nonhematopoietic effects of erythropoietin have also been shown. It may act as a new angiogenic factor in wound healing. This study aimed to investigate the effect of systemic administration of recombinant human erythropoietin on wound healing in mice. Dorsal incisional wounds were performed in mice, which were then divided into two groups; a group treated for 7 days with recombinant human erythropoietin, and a control group. Sacrificing animals on day 7, the wound tissues were collected for analysis of wound breaking strength, malondialdehyde, a marker of lipid peroxidation, hydroxyproline, an index of reparative collagen deposition, reduced glutathione levels, and for histological evaluation. The immunohistochemical determination of vascular endothelial growth factor (VEGF) which is believed to be the most prevalent angiogenic factor throughout the skin repair process, was also studied. The treatment significantly increased wound breaking strength by decreasing malondialdehyde and increasing hydroxyproline levels on day 7 after wounding. No statistically meaningful change was observed in reduced glutathione content. VEGF was immunostained significantly more on wound tissue of treated animals compared to the control group. Recombinant human erythropoietin treatment may be effective in wound healing due to inhibition of lipid peroxidation, deposition of collagen, and VEGF expression in wound area. [ABSTRACT FROM AUTHOR]

Objective: To study the tensile strength of tracheal anastomoses. Design: Experimental study. Setting: University medical school laboratory, Germany. Animals: 15 sheep. Interventions: Tracheal anastomoses with three different suturing techniques: a continuous suture and interrupted sutures with either a monofilament or a polyfilament material. Anastomoses were tested to breaking after being in place for 1, 2, 4, 8 or 24 weeks. Results: After one week, with all three materials, the trachea broke at the anastomosis. In animals that survived longer, the trachea broke further away from the anastomosis. There was no significant difference between the mean values of the breaking force for continuous sutures and single interrupted sutures (p = 0.9). Conclusion: The suturing technique (continuous or interrupted) has less relevance for the tensile strength of the anastomosis than in vitro experiments suggest. [ABSTRACT FROM AUTHOR]

The desirable properties of yarns to be used for industrial applications are discussed, and the results are given of tests on a series of polyester-fibre yarns and one nylon yarn. The effects of intrinsic viscosity, draw ratio, and relaxation on the mechanical properties of the yarns are considered. It is shown how the conversion efficiency may be determined from the load-extension curve of a singles yarn, and the calculation of the conversion efficiency for a yarn to be used in a tyre cord is illustrated. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented regarding the prediction of yarn strength.

The major properties of a new type of bulked yarn, closely resembling that produced by the air-jet process but made without the use of such a jet, are described. These properties are then interpreted with respect to the important processing variables. The increase in linear density is affected by increases in overfeed, bulking-zone length, and parent-yarn linear density per filament. It is argued that changes in the yarn tension within the bulking zone are likely to be modifying the theoretical values of overfeed, and this accounts for the percentage increase in linear density being consistently different from the percentage overfeed. The percentage physical bulk also increases with the overfeed and with the yarn and filament linear density, but this is shown to be an unsatisfactory method of test. An improved method, involving water absorption, shows that this property reflects the influences of changes in all the major process variables. Increasing values of overfeed and parent-yarn twist lead to weaker and less extensible bulked yarns, and the most significant processing parameter to affect the yarn stability is the overfeed, which gives progressively less stable yarns as its value is increased. These properties of the new yarns are generally comparable with those of air-jet-bulked yarns, and they are related to common features in their physical structures. [ABSTRACT FROM AUTHOR]

The stress-strain behaviour (at constant rate of extension) for fibres at 0, 65, and 100% r.h. is compared. At 100% r.h., the material yield slope is close to zero, whereas a rapid stress relaxation at 65 % r.h. leads to a negative slope. This latter effect tends to be masked by fibre non-uniformity. The fibre-material yield slope at 0% r.h. is quite large, and the slow turnover from Hookean to yield is probably an interaction between this slope and fibre non-uniformity. Constant-rate-of-loading tests by others do not indicate a negative slope at 65% r.h., and the material yield slope at 0% r.h. appears to be significantly higher for this mode of testing. The variation in the stress at 15% extension in water from fibre to fibre appears to be mainly due to microfibril-proportion differences existing between fibres. A similar effect for the Hookean slope in water tends to be complicated by additional crimp effects. The post-yield-region variation decreases for lower humidities, and an explanation in terms of the series-zone model is suggested. Fibre non-uniformity greatly affects the observed breaking properties, and the actual material breaking properties are derived from the results. [ABSTRACT FROM AUTHOR]

Treatments designed to increase and decrease friction were applied to rayon staple fibre before processing, as card web, and after needling. Basic frictional properties of the fibres were examined. The first two groups were processed into needled fabrics, and it is shown that considerable damage occurs with high-friction fibres: this results in a deterioration in mechanical properties. Even a wet process without additive causes some loss of strength. However, treatment with a high-friction additive after needling results in increased strength in the fabric. [ABSTRACT FROM AUTHOR]

It has been shown in the preceding paper how high-speed cam systems were desired to give substantial increases in the rate of fabric production of weft-knitting machinery. This paper provides a detailed analysis of the effect of cam shape on the knitting-yarn tensions, machine performance, and individual needle forces. It is explained that, although the yarn tensions developed within the knitting cycle are greater for high-speed cams than for conventional linear cams, these tensions do not affect the resulting fabric appearance or the machine performance. In addition, calculations of individual needle forces and high-speed trials indicate that speeds many times as great as commercial speeds may be achieved with the mathematically designed high-speed cams. [ABSTRACT FROM AUTHOR]

A critical assessment of the merits of core-spinning by means of comparisons of the strength and extension of core-spun yarns with all-staple-fibre yarns forms the basis of this paper. Core-spinning was done by introducing the filament under tension into the drafted strand as the latter entered the front rollers of the ring-frame. A 20-den (2.2-tex) nylon monofilament was used as core, and three types of staple-fibre covering were investigated. The effects of twist, pre-tension, and feeding arrangements on the geometrical disposition and tensile properties of the yarns were examined. Irnprovements in strength are, in general, realized at low twists by the incorporation of the filament and by further constraining it to occupy the core. The contribution of the components to the yarn strength and the process of breaking were also subjected to a detailed study. The studies reported provide an interesting insight into the extent of cohesion developed between the fibres during the straining of the yarn and its influence on the process of breaking and ultimately on yarn extension. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The STT system is one in which unidirectional twist is added to self-twist yarns to produce two-ply weaving yarns. The added twist required for the elimination of fabric patterning due to cyclic twist variation in the yarn has been determined and has been expressed in terms of the amount of self-twist in the yarn. Fabrics woven from STT yarns have been evaluated, and the dependence of fabric properties on initial self-twist and on added-twist levels has been investigated. This has resulted in recommendations for the spinning and twisting of STT yarns for use in making high-quality worsted fabrics. [ABSTRACT FROM AUTHOR]

Cotton fabric has been methylated under a variety of conditions. The extent of methylation has been shown to be dependent on the time of methylation and on the degree of swelling or disruption of structure. The latter is caused by the alkali pretreatment or by the swelling of the partly methylated cellulose. Fabric physical properties have been measured and the influence of the methylation treatment has been examined. [ABSTRACT FROM AUTHOR]

This paper describes an empirical method for choosing a twist level for a new tyre cord that will 'match' the twist in an existing successful cord, i.e., one that will give the same twist angle. The technique is based on published cord geometry and is shown to give reliable results. No knowledge of densities or packing factors is required, and the results are independent of the number of yarns in the cord. The method offers the possibility of calculating twist angles and related properties for cords at any twist once a sufficiently reliable value of one cord constant has been determined. A table of matched twists calculated in this way is given. [ABSTRACT FROM AUTHOR]

An account is given of an investigation in which gross particles consisting of either jute or viscose rayon fibres of different lengths and diameters were spun in both secondary cellulose acetate filaments and a polyurethane elastomer in order to verify whether a significant degree of reinforcement was possible with a composite material of this type. The mechanical properties of the composite cellulose acetate fibres were studied, and it is shown that both types of filler produced a decrease in breaking extension and an increase in initial modulus with increasing filler content. The strength of the jute-filled material is also shown to increase. Similar effects on the breaking extension and initial modulus of the rayon-filled polyurethane filaments were observed, and here there was also a decrease in strength that arose from the difference in extensibility between the rayon and the polyurethane filament. [ABSTRACT FROM AUTHOR]

study of the changes in mechanical properties of cotton brought about by sodium hydroxide, an iron tartrate complex in caustic soda (EWNN), cuprammonium hydroxide, and sulphuric, phosphoric, nitric, and perchloric acids has been made. Instead of choosing the normal mercerizing conditions with sodium hydroxide, different temperatures of treatment and of washing were studied to see what effect the condition had on the subsequent mechanical properties of the fibres. The variable studied with the other reagents was that of concentration, so that a distinction between interfibrillar and intrafibrillar swelling could be made. The main effect of swelling is to alter the extensibility of the fibre, and this has been analysed at different stages of loading up to break. [ABSTRACT FROM AUTHOR]

An account is given of a study of the effect of the amount of activating agent, the temperature, the catalyst, and the diluents used in the acetylation of cotton with perchloric acid as catalyst. Sulphuric acid was compared with perchloric acid as a catalyst. The effects of traces of water, the amount of acetyl chloride, and the rate of acetylation were studied in the acetylation of cotton with acetyl chloride and pyridine. The conditions in all cases were such that the acetylated cotton retained its fibrous form. [ABSTRACT FROM AUTHOR]

Steely wool has a low crimp rate and low strength and doggy wool a low crimp rate but normal strength, so that both wools are exceptionally useful experimental materials. An account is given in this paper of a comparison of the processing behaviour of wools of the two types with that of matched normal wools from yarn to fabric. The tensile properties and abrasion-resistance of the anomalous wools were as expected, but an unusual effect of the steely wool in washing shrinkage was found. The presence of steely-wool yarn in one direction (e.g., warp) caused increased shrinkage of the yam in the cross direction. Thus, in a fabric with a steely-wool warp yarn and a normal-wool weft yarn, the shrinkage index of the weft yam increased from 1.8 to 3.0; when the normal-wool yarn was used as warp with a steely-wool weft, the increase was from 1.7 to 2.4, This co-operative shrinkage did not occur with the doggy wool; it is thought to be caused by the low tensile modulus of the steely wool. [ABSTRACT FROM AUTHOR]

A processing programme is outlined in which yarn pre-twist, applied air-pressure, and supply-yarn overfeed are systematically varied in the air-jet bulking process to investigate their effects on air-textured nylon 6.6 continuous-filament yarns. Optical magnification of the air-textured yarns enables the average loop sizes and frequencies to be measured. The experimental results are shown to be in general agreement with a suggested mechanism of the process, which argues that the initial filament twist in the parent yarn redistributes itself as snarled loops and that the overfed yarn contributes to the size of such loops; the deflexion of filaments by air-drag forces is also shown to make a contribution to a looping effect, which can be estimated theoretically. Increasing the yam overfeed increases both the loop size and the loop frequency. Increasing the yam pre-twist decreases the loop size and increases the loop frequency. Increasing the air-pressure also decreases the loop size and increases the loop frequency. Experimental and theoretical results are in general agreement. As would be expected, the only processing condition that effects a change in linear density is the overfeed, but all the processing conditions that have an effect on loop dimensions also have an effect on the change in volume, i.e., on the physical bulk. Overfeed is the greatest single contributor to physical bulk, since both loop size and loop frequency increase with overfeed, occluded air spaces being thereby created in yarn and fabric form; conversely, with varying twists and air-pressures, the effects of decreasing loop size and increasing loop frequency are to some extent self-balancing in their contribution to physical bulk. It is shown how the various processing parameters affect the stability of air-textured yarns. Textured yams produced from parent yarns possessing small amounts of pre-twist have a high instability because of the lack of binding twist for securing the entangled structure. Increasing the overfeed greatly increases the number and size of loops, and this causes greater instability. Increases in the applied air-pressure also increase the yarn instability. Two new mechanical techniques have been devised to measure the yarn instability, and these have been found to be greatly superior to the stability-testing apparatus normally used, which has serious defects from the viewpoint of accuracy. The tenacity of the air-textured yarns tends to decrease for increasing values of all the main processing variables considered. Increasing the yarn pre-twist tends to reduce the percentage elongation at break, but independent increases in the supply-yarn overfeed and the applied air-pressure both tend to increase this characteristic. These results are interpreted in the light of the bulking mechanism previously postulated. [ABSTRACT FROM AUTHOR]

Two greasy-wool bulks were made up from sound fleeces selected from a single medium-merino flock so that their mean diameters, mean staple lengths, and mean crimp frequencies would be the same or similar, but the coefficients of variation of diameter (Kd) would be different. The tops made from these bulks showed closely similar mean fibre diameters (20·6 and 20·8 (μm), lengths, and length variabilities, with the Vd values 18·3% (L) and 21·4% (H). In conventional Bradford spinning, L was slightly favoured over H at the spinning limit, but the differences in ends-down per 100 spindle-hours at commercial counts were negligible. Yarn properties, such as tensile strength and elongation at break, and yarn evenness did not disclose differences of any consequence. Fabrics made from 25-tex yarns gave closely similar properties. Ambler Superdraft spinning supported these conclusions. The difference of 3% in Vd values did not indicate significant worsted-manufacturing differences between the tops. Since these tops were made from single-quality sources, the Vd values are low compared with the range of values for European tops of the same diameter, the majority of which would occur in the 20-26% Vd range. [ABSTRACT FROM AUTHOR]

Changes in the coefficient of variation of fibre diameter (Vd) were made by blending top qualities (a) 70s and 56s, and (b) 60s and 56s, and comparing these with a 58s. In this way, a range of values of Vd from 21·4 to 24·9% was obtained over three top samples whose mean fibre diameters and fibre lengths were closely similar. These tops were worsted-spun to determine their performance at the spinning limit and other yarn counts and to measure the yarn properties. The three samples did not give any important differences in chemical composition or in spinning limit, but did show a trend to significant differences in yarn breaking strength and elongation, the lower-Vd sample being favoured. Over this range of values of Vd at mean diameters of 25-26 μm, although there are hints of slight differences in spinning and in the product, the trend is not important. The range of Vd values for European tops of mean fibre diameter 25·3 μm appears to lie between 22 and 28%. The Australian tops investigated gave Vd values over the lower half of this range. [ABSTRACT FROM AUTHOR]

This paper describes laboratory experiments designed to show what improvements can be achieved in the properties, particularly the modulus, of ICI nylon 6.6 tyre cords. The experiments fall into four groups: (i) hot-stretching tyre cords under conditions more severe than those conventionally used, up to the maximum temperatures and tensions possible; (ii) as in (i), but using cords made from hot-stretched yams; (iii) as in (i), but using twist levels lower than the conventional ones; (iv) as in (iii), but using cords made from hot-stretched yams. [ABSTRACT FROM AUTHOR]

A method is described whereby the shrinking property of wool can be modified during growth by the administration of chemical additives to the sheep's diet so as to enter the character of the fibre half-way through the growth of the staple. Thus, hard-root-soft-tip fibres can be grown to enhance shrinkage and soft-root- hard-tip fibres to impart shrink-resistance. Methods of modifying the shrinkage of wool have so far been confined to chemical treatments of the shorn fibre, but this original approach to shrinkage control also presents an opportunity for the mass production of a large variety of other types of special-purpose wools. [ABSTRACT FROM AUTHOR]

The distributions of mass of short lengths of jute yarn are described, and the effect of test length is examined. Indices of irregularity for jute yarns are developed, and descriptions of thick and thin places are given. A proposal, based on counting techniques, is made for a simplified yarn-mass analyser. The relations between mass variability and breaking-load properties are also described. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented about the twisting of cotton yarns.

A letter to the editor is presented discussing the technique for reducing yarn breakage during the knitting of fine worsted yarns.

A reply by W. R. Lang to a letter to the editor about his article on the effect of variability of fiber diameter on worsted processing is presented.

A letter to the editor is presented in response to the article "The Stretch and Recovery Behaviour of Elastomeric Yarns," by N. Wilson in a 1967 issue.

A response by N. Wilson to a letter to the editor about the article "The Stretch and Recovery Behaviour of Elastomeric Yarns" in a 1967 issue is presented.

A letter to the editor is presented regarding the carbonizing of combing wools.