Optimally wound
The engineering scientist and mathematician Yordan Kyosev
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Yordan Kyosev (Fotos: Uschi Heidel). Click here for a larger image.  |
From mathematics to virtual yarn to the blue pullover. A portrait of the engineering scientist and mathematician Yordan Kyosev.
There they stand, all lined up. Reels of different sizes, with white yarn spun onto them. The shelves are full of them, right up to the ceiling. Yordan Kyosev passes his fingers over the material, stops and pulls one of the reels out. "Here, the thread hasn't been rolled up properly. This can cause problems in processing." The friendly young man wearing a dark blue jacket with a stylish, fashionable necktie is neither the proprietor of a textile or a sewing shop, nor does he work for any testing station. Rather, his strengths lie in mathematics, and he gets round to the yarn with the aid of the computer.
The 34-year-old Bulgarian sits in front of the screen for more than ten hours a day, honing mathematical models for optimum virtual yarn. The splendid view of Aachen's old city with its Cathedral and Town Hall that his eighth-floor study affords cannot distract him from his work. By the end of the year, this mechanical engineer for textile engineering and textile technology aims to have his software developed to a point where it will pass a practical test.
Yarn and mathematics
Computer-based models of yarn - scientists prefer to speak of "textile thread" - are nothing new. Numerous papers exist that examine thread or fibres like steel wires and consequently use computer programmes for metals to calculate their properties. "This is possible with some applications, but it doesn't have much to do with the actual facts about yarn," says Yordan Kyosev, who became acquainted with traditional textile manufacturing such as weaving and spinning by hand at his grandmother's, when he was a boy.
During his Humboldt Research Fellowship at the Institute of Textile Engineering at "Rheinisch-Westfälische Technische Universität" (RWTH) Aachen, Kyosev intends to approximate textile reality mathematically. To this end, he is developing theoretical and algorithmic principles with which he can examine the structure and dynamics of yarn and its influence on its application properties. In other words, Yordan Kyosev is interested in the insides of yarn, which he would like to represent in an optimum model. "I am analysing the forces and interaction between the individual fibres and am attempting to develop a mathematical model setting out from this more mechanical angle."
There are a lot of questions to answer. How do you have to rotate the fibres to produce high-quality yarn? How can you use raw material of inferior quality to make excellent yarn? How can you avoid spoiling the quality of high-grade raw material during production and processing? The engineer and mathematician is looking for mathematically calculated parameters that can be used flexibly like tools in yarn production and various textile processes at a later stage. These parameters have to be adjusted according to the material's structure, be it cotton, linen or wool.
Virtual reels
Yordan Kyosev. Click here for a larger image.  |
Initially, his virtual yarn will be useful for static and dynamic simulations, especially in winding up reels, and later on in the construction of textile fabrics such as woven cloth. To this end, the researcher designs virtual reels at the computer onto which threads are woven with the aid of algorithms. In figurative terms, the virtual yarn is spun onto the reel with, for example, density, tension and internal stability being kept in optimum relation to one another. This kind of reel is likely to ensure high quality and frictionless operating processes later on in production. The thread runs smoothly, the reel does not break apart, and strain on the material is minimal.
Let's take a dark blue pullover. To make the best of the colour, the yarn has to make even contact with blue everywhere when the reels are dyed. The success of this will depend on how the yarn is positioned on the reel. And this positioning will in turn be determined by the yarn's properties and the properties of the spooling frame - a multilayered process. Yordan Kyosev also wants to simulate such processes in computer-aided programmes in order to control them.
At the moment, the mathematician is still working on the foundations, most of which is theoretical, and is verifying them in the laboratory. "I process a large amount of measuring data from the laboratory in the computer, for I can't make any progress without laboratory results." Even so, Yordan Kyosev has to understand the concept as a whole as well as the complex relations in order to be able to translate everything into mathematics. Nevertheless, the practical relevance of his research does not seem to be as far off on the horizon as the high level of abstraction in his work would suggest. In the institute corridor opposite his study, the laymen can get an inkling of what textiles can be used for beyond the world of fashion. There, lightweight components made of textile fabrics and fortified with adhesives can be seen as well as textile netting for insulation purposes or concrete reinforced with textiles, a new compound material - all of them examples of the wide range of applications. In medicine, too, textiles can be used for implants, for instance in the shape of multidimensional textile structures serving as small tubes. A colleague engaged in research in this area recently asked Yordan Kyosev to share his mathematical modelling insights.
A proximity to practical applications and industry
Yordan Kyosev. Click here for a larger image.  |
At the Aachen institute, the Bulgarian engineer has at his disposal what his own higher education institution, Sofia Technical University, cannot offer: a direct link between theory and application supported by state-ofthe- art apparatus as well as a proximity to industry. His host and head of institute, Professor Dr. Thomas Gries, has consciously opted for junior scientists from Eastern Europe, Iran, India and Pakistan. "The young researchers have enjoyed excellent theoretical training. Usually, they are better than their German colleagues at mathematics, which is also due to the fact that there were fewer opportunities for application at their own universities. This is precisely why they complement our work so ideally." Gries actively wants to encourage young researchers with a profound knowledge of mathematics and engineering sciences to come to Germany "for many of them are often not aware what prospects they can open up for themselves with the know-how they have acquired." What counts is to tap this potential.
Yordan Kyosev recognised these opportunities a number of years ago, when he was able to carry out the investigations required for his doctoral thesis at the "Hochschule Niederrhein" and at a leading textile machine manufacturer's. "In Sofia, I would not have managed my doctoral studies in this way. For a start, the data and modern machines would have been missing." Since then, he has worked as a senior assistant at the chair for textile engineering at Sofia Technical University. He intends to qualify as a post-doctoral university lecturer with his research work in Aachen in the near future.
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