In this work, fiber distribution through the cross-sections of compact yarns and their packing density values was investigated to provide a better understanding of the internal structures of compact yarns produced by different compact spinning systems, since there is no information available so far regarding their internal structure. The results of packing density analysis indicated that compact yarns had nearly 15—30% higher packing density values compared to that of the conventional ring spun yarns. Also, the packing density values of compact yarns produced by three different compact yarn spinning systems, namely Rieter K44, Suessen Elite and Zinser Air-Com-Tex700, revealed that there were no significant differences among these systems in terms of yarn packing density values.

This study compared the characteristic properties of the yarns produced on three different yarn spinning systems with the same material. These spinning systems are conventional ring, compact, and compact-jet. Compact-jet is a proper combination of compact and jetring-spinning systems and therefore it is less known. On the other hand, conventional ring and compact spinning systems are well known in the spinning field. When the compact-jet spinning system was designed, it was aimed to gather the advantages of the jetring and compact spinning systems. Therefore, an air nozzle was placed between the exit of the RoCoS compact unit and the yarn guide of the spinning system. At the end of the study, it was determined that the compact-jet yarn properties are different from that of the conventional ring and compact yarns. The compact-jet spinning system is mainly effective on yarn hairiness and compact-jet yarn is superior compared with other yarns.

It is well known that yarn produced using the compact spinning technique, which has been introduced as one of the best spinning innovations of this century, has superior yarn structure and quality, especially in terms of hairiness and strength. However, there are different compact spinning systems on the market from different manufacturers and information concerning the favorable and unfavorable properties of each would be of great interest. In this study, we compared the properties of yarn spun on the three main compact spinning systems commonly used today. To maintain impartiality it was preferable to refer to these three systems as system A, system B, and system C instead of using their trade names. It was found that system B seemed to be more suitable for finer yarns whereas system A generally gave better results for medium to coarse counts.

One of the clearest indicators of visual pollution in the cities are their silhouettes. Silhouettes are the faces of physical structure and historical accumulation of cities. But today many cities are full of buildings that are incompatible with each other, that are disrespectful to the environment and that have no identity. Generally, city silhouettes consist of concrete façades, they have changed into common appearances that do not stamp themselves in people's minds, and the historical environments have disappeared in this chaos.Trabzon is a coastal city where green and blue meets and which were famous for its orchards, tangerine gardens and terraces that reached the coast. But rapid and unplanned urbanization is changing the city. Moreover, with its history of thousands of years, it is not possible to see these riches effectively in the city which carries the traces of different civilisations. This paper seeks to investigate the traces of change and transformation that the city has undergone in the silhouette of the city. Interventions in the city and visual pollutions in the city silhouette as a result of these interventions will be considered. In this context, by comparing the new photos of the city with the old ones, the aesthetic value and visual quality of the city will be evaluated.

No abstract

Hairiness affects the post-spinning processes and fabric appearance. In order to reduce the yarn hairiness, the present work attempted to design and develop an air nozzle that can be easily attached on to the sirospun spinning system. The system, based on a nozzle attachment to the sirospun spinning system, is named the siro-jet. In our previous studies, the nozzle was used in ring and compact spinning processes and the changes in yarn properties were analyzed. In this study, various nozzles having different injector angles, main hole diameters, injector diameters, number of injectors, nozzle shapes and injector positions were used and siro-jet yarns were produced at different air pressure levels. At the end of the experiments, it was determined that there is an optimum value for each nozzle parameter, and that the number of injectors and injector position play the most important roles in reducing yarn hairiness, whereas nozzle shape shows the weakest effect. On the other hand, the findings showed that it is possible to get lower hairiness values by different modifications on the same nozzle design. Considering the hairiness results, a constant was defined indicating the relationship between nozzle structural parameters and hairiness of the yarns to ease the nozzle design efforts. Depending on nozzle type, the siro-jet spinning system truly improves the yarn hairiness by 40-75%. In the literature, many researchers used an air nozzle in the spinning and also the winding processes. However, the combination of the air nozzle and sirospun spinning system in this manner is still not a common application.

In order to make a contribution to the reduction of raw material costs, in the present study the effect of reused cotton fibres on the quality of conventional ring and OE-rotor yarns was investigated. In the yarn production, it three different waste fibres were taken from a cotton yarn production line and blended with primary cotton fibres at five different levels varying from 5% to 40%. In literature, studies have concentrated on the usage of recovered waste fibre in OE-rotor yarn production. However, to date there has been limited extensive and comparative research on the effect of recovered fibre quality on different yarn properties to determine the possibility of high-quality yarn production from reused fibres. In the study, we focused on the effect of different waste types as well as the amount of waste in the blends on the properties of different yarn types.

Jetring is a modifi cation of the conventional ring spinning system and based on the usage of an air nozzle and pressurized air during yarn spinning. This study researched the characteristic properties of Jetring yarns and compared Jetring and conventional ring spun yarn properties. For the Jetring yarn production, three different nozzle types having different injector angles and four different air pressure levels were used. In addition to 30 ° and 45 ° injector angles, which are widely reported in literature, the effect of an angle of 15 ° was also studied. At the end of the study, the differences between Jetring and ring spun yarns were determined. It was found that the Jetring spinning system produces yarns having a hybrid character between conventional ring and air-jet yarns. Additionally, the yarn properties of Jetring yarns highly depend on nozzle structural parameters and air pressure level.