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The purpose of this paper is to define the relationships between the structure of multi-thread fancy yarns and the combination of the rotational speed of the hollow-spindle spinning system and thickness and stiffness of the effect component.

To do so, two groups of fancy yarns were made using stiff and soft effect threads and at six different machine settings.

It was found that the stiff effect thread was suitable to make fancy yarns at low rotational speeds, while the thickness of the effect threads was more important than its stiffness at low number of wraps. Additionally, even when using the same number of wraps and the overfeed ratio, a bouclé yarn, a gimp yarn, a wavy yarn or a loop yarn may results if the thickness and stiffness of the effect thread and the rotational speed were all controlled properly.

This study helps fancy yarn spinners to determine the type of final fancy yarns by controlling the spinning geometry in the first spinning zone.

The purpose of this paper is to define the relationships between the first spinning zone of the hollow-spindle spinning system and technological parameters of manufacturing multi-thread fancy yarn.

A simple mathematical equation was introduced to account for the effect-thread helices. The validity of this equation was tested using visual observations of the helices of the effect thread in terms of their number, width and regularity and then compared against the theoretical values.

It was found that higher overfeed ratios increased the diameter of the helices without affecting their number, while increasing the rotational speed increased their number but reduced their diameter. The effect of these changes on the fancy yarns was that higher number of helices resulted in more fancy profiles while wider helices resulted in larger fancy profiles.

This research offers fancy yarn manufacturers a better understanding of the manufacturing process of fancy yarn and its practical advantage is to help them in determining the type of the resultant fancy yarns by controlling the geometry of the first spinning zone.

The purpose of this paper is to mathematically model the structure of doubled fancy yarns made by combining together several threads.

It was assumed that such a structure may have two distinctive parts – sinusoidal and helical (i.e. sigmoidal). This model is based on calculating the length of the effect thread in relation to the core thread. The case of having several variants of such a structure was discussed to account for several types of doubled fancy yarns. The number of wraps of the binder, the overfed ratio, and heights of the fancy profiles in the different parts were the fundamental parameters of this model. The effects of changes in the number of wraps, the overfeed ratio or both simultaneously, on this model, were also considered. The shape factor of fancy yarn was also modelled depending on the basic model of the structure.

The model was tested and the correlation coefficient between the theoretical value and the real value of length of the effect thread was 0.90.

This model is useful for predicting the length of the effect component based on the type, dimension and number of the fancy profiles of doubled fancy yarn, and for understanding the changes of the multiple-thread structure of fancy yarn when the overfeed ratio and/or the number of wraps were to change.

This study aims to show the dyeing behaviour of polyester fabrics using four novel heterocyclic disperse dyes.

The four dyes were synthesized based on 5, 5'-(1, 4-phenylene) bis (1, 3, 4-thiadiazol-2-amine) as a diazonium compound. The UV/Vis absorption spectroscopic data of these disperse dyes while dyeing polyester fabrics were investigated. Following this, the dyeing properties of these dyes on polyester fabrics were investigated under acid condition.

The results showed that increasing the dyeing temperature from 80°C to 100°C led to an increase in dye uptake for all dyes, but further increases of the temperature to 130°C led to higher dye uptake for dye 3 as the dye exhaustion increased by about 50% from 55.9% to 91.4%.

This study is important as it introduces new dyes for the dyeing of polyethylene terephthalate (PET) fibres with colours that range from yellowish orange to bluish yellow and scarlet red and all with excellent brightness, levelness and depth of shade.