Comparative Analysis of the Ring Spinning Process, Both Classic and Compact: Theoretical Reflections

Stanisław Lewandowski, Robert Drobina, Comparative Analysis of the Ring Spinning *Ignacy Józkowicz Process, Both Classic and Compact: Institute of Textile Engineering and Polymer Materials, Theoretical Reflections. Part 1: Elaboration University of Bielsko-Biala, ul. Wilowa 2, 43-300 Bielsko-Biała, Poland of the Statistical Model Based Textile and Clothing Company „Teofilów” S.A. ul. Szparagowa 6/8, 91-211 Łóź, Poland on Multiple Regression Abstract The analysis of the parameters of the spinning process was conducted of the quality of the yarn and the efficiency of the production, and it was confirmed that the percentage of noils and the metric coefficient of the twist were important factors. The analysis of the simultaneous influence of both factors on the chosen properties of classic cotton yarns, and of the nominal linear density 20 tex of compact yarn, was conducted by means of statistical models based on multiple regression, after conducting two total experiments of the type 5×5. The verification of proposed models will be presented in the second part of the article.

Key words: classic yarn, compact yarn, percentage of noils, twist factor, Rieter company spinning plan, total experiment, double classification, multiple egression.r

Tests focused on compact spinning were The percentage of fibres removed from n Introduction being carried out in foreign countries [3, the noils influences the tenacity of the 26 − 28, 35, 36] and in Poland [4, 5, 11, combed cotton yarn [12]. However, in- Until the early 60s, the main type of 13 − 18, 21, 22, 39]. vestigations relating to the simultaneous spinning machines were ring spinning influence of the number of twists and the frames, which were used in all types of percentage of noils on the physical pro- spinning systems. In the 70s, open end The technological prieties of analysed yarns were not car- spinning was developed, mainly rotor identification of ring spinning, ried out. The metric coefficient of the spinning, with reference to cotton and both classic and compact twist of roving, and parameters which are cotton-like yarns [10]. However, ring one of the factors essentially connected crucial to the composition of the roving spinning frames are still competitive in package, are characteristic technologi- relation to rotor spinning machines, and with the quality of the yarn, as well as the cal parameters in the case of the roving in some systems they are impossible to efficiency of the spinning process, is the frame. The characteristic technological replace [10]. The barrier to technologi- spinnability of fibres, and many work- parameters of the work relating to the cal progress in the ring spinning system, ing parameters of the spinning machines ring spinning frame are the metric coef- is the necessity of keeping the rotational are applied in the individual technologi- α motion of the bobbin in order to twist cal operations [12]. However, there is ficient of the twist of the yarn − m, and the yarn. Consequently, the values of the also a group of technological parameters parameters which are crucial to the com- bobbin and the speed of the spinning, re- which are characteristic to the individual position of the yarn package. The coef- α sult in the rate of production being lim- technological operations of the spinning ficient − m is one of the innumerable ited [10, 12]. In the mid 90s, the unsatis- process [12, 23]. parameters influencing the quality of the factory structure of the O-E yarn made of yarn, particularly its strength, and the ef- short fibres, cotton and cotton-like fibres, In the case of combers, the characteris- ficiency of the spinning process. The pa- reversed the trend in developing new tic parameters are the length of the linear rameters mentioned determine this if the designs of machines. The specific char- feeding − F, and the sorting zone − S, di- yarn is designed to the weaver’s aims, if acter of the ring spinning system forced rectly influencing the percentage of noils the yarn is to be knitted, and also if it is to the machine producers to develop new − pw. The percentage of noils is directly be hand knitted. The metric coefficient of techniques to improve the quality, even dependent on the length of the sorting the twist of the yarn − αm directly influ- if lowering the rate of production [1]. In zone. This determines the length of fi- ences the efficiency of the spinning proc- the classic type of spinning system, while bres combed out from the sliver, and thus ess [23]. twisting the stretched sliver, a spinning influences the efficiency and the quality triangle of considerable dimensions oc- of the combed sliver, and the percentage In the opinion of L. Beltran, L. Wang and curs, causing great hairiness and also quantity of noils. The size of the sorting X. Wang, [2] the size of the ring, the mass strength. Further development of ring zone also indirectly influences the pro- of the traveller, and the rotary speed of spinning was adjusted to decrease the duction of the comber because, with the the spindles, influence the spinnability spinning triangle by using other systems, enlargement of the zone, the efficiency and the physical proprieties of ring spun including the compact system [32]. of the combed sliver changes. Following yarns. It was confirmed in the cited refer- traditional symbols applied in the textile ence, that the most important parameters Factors which were introduced led to the industry, the term percentage of noils − influencing the quality of the produced rise of new techniques in spinning, in pw in % will be used in the rest of the yarn and the efficiency of the spinning particular, the ring compact technique. article. process are pw and αm. Enumerated pa-

20 Lewandowski S., Drobina R., Józkowicz I.; Comparative Analysis of the Ring Spinning Process, Both Classic and Compact: Theoretical Reflections. Part 1: Elaboration of the Statistical Model Based on Multiple Regression. FIBRES & TEXTILES in Eastern Europe 2010, Vol. 18, No. 4 (81) pp. 20-24. rameters were used in the design of the Changes of the definite input variables ˆ 2 2 Yi = B0 + B1 ⋅ α m + B2 ⋅ pw + B11 ⋅ α m + B22 ⋅ pw + B12 ⋅ α m ⋅ pw plan of the experiment. In order to ful- only make sense when they are consid- ˆ = + ⋅ α + ⋅ + ⋅ α 2 + ⋅ 2 + ⋅ α ⋅ (1) fil the requirements of the comparability ered in connection Y withi B 0 differentB1 m inputB2 pw B11 m B22 pw B12 m pw of both techniques of ring spinning, i.e. variables [25]. The danger exists that the where: classic and compact, the remaining pa- separate investigation of the influence of T [B0 ;B1;B2 ;BB1111 ;B2222 ;B1212 ] – the vector rameters, including both kinds of applied individual input variables, can cause their of the coefficients of the function of the fibres, their physical proprieties, and the elimination a priori, thanks to the lack of regression, settings for the work of spinning frames, significance. On an analysed process or ˆ Yi – the value of the function of the re- were accepted as constant sizes. phenomenon, however, when they are gression calculated for i, the physical considered simultaneously, they can then parameter of the yarn. turn out to be essential [25]. In the case of Design of the plan the programming of investigations with of the experiment Two total experiments of the type 5 × 5 the use of orthogonal regression, the con- were conducted, with the aim of accom- The forecast of spinnability and the phys- figuration of the matrix of the experiment plishing the profound penetration of the ical proprieties of yarns can be carried has to be programmed in such a way that space of input sizes, comprising 50 tests out using mathematical formulas, based the values of the input variables distrib- altogether (see Figure 1). on the theoretical and physical knowl- ute themselves along the main diagonal edge of the process. The comprehensive of this matrix, or after the block of these information about the process itself in this diagonals [6]. Orthogonal regression is Design of an adequate plan case, accessible through the possibility of useful to investigation cases enabling of the spinning, making it using physical, chemical, and mechanical analyses of the simultaneous influence possible to carry out the total equations, gives the user a thorough in- of many factors on the size and physical experiment proprieties of yarns. By using this, one sight into its course. However, as a result The plan of the spinning of cotton yarns, can formulate orthogonal equations of of the huge size of the input vectors and both classic and compact, was introduced the regression, determine the coefficients the exit vectors, relating to the process in the form of the flowchart in Figure 2 of the correlation, and estimate their sig- of the production of yarn and its interac- (see page 22). The experiment was di- nificance. Orthogonal regression also al- tions, the exact mathematical model of vided into two parallel phases, making lows the determination of the intensity spinning frame has not been worked out 50 tests altogether. so far, and it is hard to believe that such a of the influence of individual input variables on the size of the studied feature. model will ever be constructed [33]. Subject of examinations However, orthogonal regression has a The object of the investigations was Analysis of published reports [24, 30], series of disadvantages [6, 37]. combed cotton yarns, both classic and proves that one can also carry out pro- compact, with linear density of about gramming of investigations enabling One can also carry out the programming 20 tex. These yarns were produced in the modelling of the process of spinning, us- of investigations enabling modelling of spinning factory Zawiercie S.A. in Za- ing the statistical model relating to sta- the spinning process using multiple re- wiercie city [39]. The raw material used tistical regression. The programming of gression, and designing appropriate plans in this experiment was average-fibrous investigations relating to linear regres- of the experiment. Taking these consid- cotton Strict Midling about 13/32 “ ÷ 11/8” sion, enabling analysis of the separate erations into account, it was decided that in length and 144 mtex ÷ 157 mtex in influence of every one of the factors, has the description of the correlation between thickness. small advantages and is insufficient [30]. the parameters of the spinning process, The definite change of a labile entrance represented by the metric coefficient of Methods of the analysis only makes sense when it is considered the twist -αm, the percentage of noils - of experimental data in connection with a different labile en- pw, and the physical proprieties of yarns, trance [25]. The danger exists that the the multiple regression method will be Basic statistical parameters were assigned separate investigation into the influence applied, and a posteriori the use of linear to every analysed physical parameter of of the elimination of an individual labile square polynomials: the yarn, including average value, stand- entrance can, thanks to the lack of significance, affect the analysed process or Z phenomenon a priori. However, when they are considered simultaneously, they  can then turn out to be essential [25]. X1= m Analysis of published reports also indi- cates that the programming of investigations enabling modelling of the spinning process, can also be carried out using statistical models based on statistical regres- Figure 1. The total experiment 5 × 5 applied to the investigations of physical properties of sion. The programming of investigations analysed yarns [39]. Legend: X1 = αm = [90 100 110 120 128]T, X2 = pw = [8 10 14 18 20]T (%), Y – coefficient of mass variation − CV , Y − hairness of the yarn – H, Y based on linear regression, enabling as- 11 m 12 13 − number of thins per 1000 m of yarn – thins–50%, Y14 − number of thicks per 1000 m of sessment and analysis of the separate in- yarn – thicks+50%, Y15 − number of neps per 1000 m of yarn – neps+200%, Y16 − breaking fluence of every one of the factors, has tenacity – RH, Y17 − breaking elongation – εr, Z − non-measurable disturbances of the small advantages and is insufficient [30]. spinning process.

FIBRES & TEXTILES in Eastern Europe 2010, Vol. 18, No. 4 (81) 21 Strict Midling cotton ling the process of the production of cotton ring yarns, both classic and compact, using multiple regression, is presented in Flexible blow room Figure 3. Truetzschler

The total quality of ring spun yarns, both Tkt = 5 ktex w classic and compact, depended on vari- High performance card Vw = 90 m/min Mk4 Single Croso l Preal = 25.65 kg/h ous of their features, so it is difficult to Card tape find an objective estimation of the quality of analysed yarns, and the assessment Tkt = 5 ktex; D = 8; Rc=8; Tkt = 5 ktex Draw frame z w of their technological usefulness. A final SB2 Rieter Vw = 700 m/min; P real = 168 kg/h estimation of the quality of yarns can Draw tape be done analytically or synthetically. It UNI Lap Tktz=5 ktex; D=24; R c=1.6; Tkt w = 75 ktex is relatively easy to find the usefulness E 32 Rieter Vw = 90 m/min; P real = 344.25 kg/h of the examined product by considering Lap one of the features. In this case, it is suf- Tktz=75 ktex; F=5.2 mm/1cycle; D=8; ficient to judge the given feature through Comber n=385 cycles/min; =0.912 ;Tkt w = 5ktex E 62 Preal1 = 58.15 kg/h; P real2 = 56.88 kg/h; its measurements. The situation becomes Rieter Preal3 = 54.36 kg/h; P real4 = 51.83 kg/h; very complicated when the need to per- P = 50.56 kg/h; real5 form multi criterion assessment occurs T X2 = pw = [8 10 14 18 20] [7, 38]. One of the main disadvntages of Combing tape the analytical methods is the need to ex-

Draw frame Tktz = 5 ktex; D=6; Rc=5.17; Tkt w = 5.8 ktex amine every one of the strength features RSB 951 Rieter Vw = 450 m/min; P real = 156.6 kg/h separately from the others. Draw tape Multi criterion assessment of the measur- Tkt = 5.8 ktex; D=1; Rc=7.9 Tt = 735 tex Roving frame z n able properties of ring spun yarns, both 660 Zinser i = 96, Vw = 20.37 m/min; n spind. = 1100 r.p.m. classic and compact, was done through Roving the application of the General Index of T T Quality – G , which took into consid- X1 = m = [90 100 110 120 128] X1 = m = [90 100 110 120 128] Q T T X2 = pw = [8 10 14 18 20] X2 = pw = [8 10 14 18 20] eration tenacity – RH, coefficient of mass

variation − CVm, the number of neps per 1000 m – Neps and hairiness – H. Classic ring Compact ring +200% , spinning frame spinning frame Weights were allocated to enumerated G33 Rieter ComforK44 Rieter features arbitrarily in the three-stage scale – 1, 2, 3: n the highest mark of importance – Figure 2. Plan of the spinning of cotton yarns, both classic and compact [39]. Legend: t = 3 and t = 3 were allocated to Rc – total draft, D – doublings, T – linear mass of slivers (ktex), V – the linear speed of CVm H ktz w the coefficient of mass variation CV the machine (m/min), nspind – the rotating speed of spindles, Preal – real productivity per m machine, F – linear feed (mm/1 cycle), η − efficiency, i − the number of outlets (delivery and hairiness – H, since these param- points). eters play the most significant part in the latest stages of the technological ard deviation and the coefficient of vari- [9, 34], followed by the multiple regres- process, especially from the point of ation. In order to carry out a comparative sion method a posteriori, together with view of undesirable breakage, and the assessment of the physical proprieties of determining the appropriate functions view of the finished article [8]. classic cotton yarns produced on a ring with approximate linear square polyno- n the mark of importance − tNeps+200% = 2 spinning frame G33, with compact yarns mials [24, 34]. For statistically adequate was allocated to the number of neps produced on a spinning frame K44, abso- models, suitable graphs of the regression per 1000 m. The neps content in yarns is still one of the most important qual- lute and relative differences of the aver- function were prepared, considerably fa- ity parameters in the textile industry, age values of individual parameters were cilitating the interpretation of the studied especially in the appearance of fabrics calculated. The processes of the produc- phenomena, together with designating and knitted fabrics, because the con- tion of the yarn on ring spinning frames, the technological parameters of the spin- sumer considers neps in the end prod- both classic and compact, were treated as ning process. In order to prove if a cor- uct to be unpleasant. A high content of processes which sent random stationary relation exists between the chosen pro- neps is also connected with consider- ergodic signals, because they were hold- prieties of cotton yarns, both classic and able processing problems that result ing the stabilised work of both spinning compact, the matrix of the correlation in, among other things, high end break frames [12]. To assess the results of the was created, enabling the calculation of rates in the knitting process [29]. simultaneous influence of theα m and pw the coefficients of Pearson’s correlation n the mark of importance – tRH = 1 was parameters on the average values of the and the estimation of their significance allocated to the tenacity. physical proprieties of analysed yarns, [34]. The detailed methodology of the the test of the variance analysis accord- analysis of the data was also described in During the tests carried out using the ing to double classification was applied articles [19-20]. The algorithm of model- form of the General Index of Quality –

22 FIBRES & TEXTILES in Eastern Europe 2010, Vol. 18, No. 4 (81) Step 1: The realization of the plan and carrying out the research experiment

Z Z X1=m X1=m Spinning frame Yi Spinning frame Yi X =p 2 w G33 classic X2=pw K44 compact Rieter Rieter

Step 2: The creation of the database a) Results of examination b) Statistical parameters of distribution

Step 3: a) Test of the variance analysis according to the double classification, b) Comparing the verification of the test for both of yarns

Step 4: Analysis correlation between selected properties of compared yarns

Step 5: Assessment of the selected properties of the yarns by means of USTER STATISTICS nomographs and creating statistical models based on the multiple regression

The choice of the technologically useful parameters Step 6: of the spinning process by means of the General Index of Quality - GIQ

Figure 3. The algorithm of modelling the process of the production of cotton ring yarns, both classic and compact, using multiple regression.

FIBRES & TEXTILES in Eastern Europe 2010, Vol. 18, No. 4 (81) 23 GQ [7, 38], average values of the meas- TISTICS, an assumption is made that the tative requirements recommended in the urable physical properties of analysed content of the short-term thick cannot ex- USTER STATISTICS. This will take cotton ring spun yarns, both classic and ceed the percentile line – 50%. place during the execution of the techno- compact, were taken into consideration, logical verification in the second part of as were the minimal and maximum value Using the above-mentioned information, the article. of these properties, random errors of the it was accepted that, if the yarns were of properties, and relative indicators of sub- sufficient quality, then the General Index jected features. of Quality would fulfil the following con- References dition: 1. Artzt P.; Melliand Textilberichte, 79, (3), Finally, General Index of Quality – GQ 1998, pp. 125−129. was expressed in equation 2 where: GQ ≥ 0.5 (3) 2. Beltran L., Wang L., Wang X.; Text. Res. J., 74, (9), 2004, pp. 757−763. tRH − rate of tenacity of analysed yarns, 3. Çelik P., Kadoğlu H., Fibers & Text. East. tCVm − rate of coefficient of mass varia- Thanks to the proposed construction of Eur., 2004, Vol. 12, No. 4 (48) pp...... tion – CVm of analysed yarns, tNeps+200% the index GQ, it is possible to choose the − rate of number of neps per 1000 m of 4. Cyniak D., Czekalski J., Jackowski T.; range of the parameters of the spinning Fibers & Text. East. Eur., 2006, Vol. 14, analysed yarns, t − rate of hairiness of H process (αm and pw), assuring the pro- No. 3, pp. 33−37. analysed yarns, and tCVm − rate of param- duction of yarns with satisfactory qual- 5. Czekalski J., Cyniak D., Jackowski T., eter – CVm of analysed yarns, ity if: Sieradzki K.; Fibers Text. East. Eur., 2007, No. 3 (60), Vol. 15, pp. 38−44. G = R+ ∪ {0.5} (4) RHi − (RH min −U R ) Q 6. Draper N. R., Smith H.; Analiza regresji W = H i ' – relative RH stosowana, PWN – Warszawa, 1973. RH max − RH min To find the technological parameters of 7. Drobina R., Włochowicz A., Machnio M.; index for breaking tenacity, Fibers & Text. East. Eur., 2008, Vol. 16, the spinning process (pw, αm), enabling CV  (CV  U ) No. 5 (70), pp. 17−23. W  1  mi m min CVm the production of yarns with the above- i ' CV m 8. Edalat-Pour S.; Application report, SE CVmmax  CVmmin mentioned properties, an analysis of the 604, USTER think quality, USTER TECH- – relative index for coefficient of mass regression function of the index - GQ was NOLOGY AG, 2007. variation, conducted: 9. Greń J.; Statystyka matematyczna – mo- H − (H −U ) dele i zadania, PWN – Warszawa, 1982. W = 1− i min H – relative iH ' ˆ 2 10. Jabłoński2 W., Jackowski T., Beskidzki H max − H min G Q = B0 + B1 ⋅α m + B2 ⋅ p w + B 11 ⋅α m + B22 ⋅ p w + B12 ⋅α m ⋅ p w ≥ 0,5 Instytut Tekstylny – Bielsko-Biała, 2001. index for hairiness, ˆ 2 2 G Q = B0 + B1 ⋅α m + B2 ⋅ p w +BB1111 ⋅α m + B2222 ⋅ p w + B 12 ⋅ (5)α m ⋅ p w11. ≥ Jackowska-Strumiłło0,5 L., Cyniak D., Cze- kalski J., Jackowski T.; Fibers & Text. ˆ = + ⋅α + ⋅ + ⋅α 2 + ⋅ 2 + ⋅α ⋅ ≥ G Q B0 NepsB1 +200m%i −B(Neps2 p w200%Bmin11 −UmNepsB+20022 % )p w B12 m p w 00.5,5 East. Eur.,2007, Vol. 15, No. 1 (60), pp. W = 1−+ iNeps '+200% 24−30. Neps200% max − Neps200% min 12. Jackowski T., Chylewska B.; „Przędzal- Neps − (Neps −U ) n Summary W = 1− +200%i 200% min Neps+200% nictwo − budowa i technologia przędz”, iNeps '+200% Neps200% max − Neps200% min The modern techniques of ring spinning, Politechnika Łódzka, 1999. – relative index for number of neps, for classic and compact yarns, make it 13. Jackowski T., Cyniak D., Czekalski J.; possible to produce high quality yarns. Fibers Text. East. Eur., 2006, Vol. 14, No. 4, pp. 36−40. where: The disadvantage of compact ring spinning is that the price of the yarns pro- 14. Jackowski T., Cyniak D., Czekalski J.; U – absolute random errors of the aver- Analysis of quality parameters of cotton duced is still too high. One can reduce the age values of the individual physical pa- yarns manufactured on ring, compact rameters of analysed yarns. costs of the production of the yarns by the and rotor spinning machines, 9 Między- suitable selection of the technological pa- narodowa Konferencja Bawełniarska, The index GQ takes into account the indi- rameters of the spinning process, which Gdańsk, 6−7 września 2007, pp. 1−10. vidual physical proprieties of yarns with involves the lowering of their quality. It ISBN 978−83. arbitrarily assumed ranks of validity. The should be remembered, however, that the 15. Jackowski T., Cyniak D., Czekalski J.; value of the General Index of Quality fundamental aim of the spinning process Fibers Text. East. Eur., 2004, Vol. 12, No. is in the range from 0 to 1, where index is getting high quality yarns, whereas the 4 (48), pp. 22−26. 16. Józkowicz I., Włochowicz A., Drobina R., GQ = 0 characterises yarns of the lowest cost of their production is of secondary quality, and index G = 1 characterises importance. The considerations present- Lewandowski S.; Przegląd Włókienniczy Q − Włókno, odzież, skóra, 2009, 63, (3), yarns of the highest quality. In industrial ed will make it possible to choose the pp. 41−44. optimal parameters of the spinning proc- practice, with the assessment of physical 17. Józkowicz I., Włochowicz A., Drobina R., proprieties by means of USTER STA- ess of yarns in order to fulfil the quali- Lewandowski S.; Przegląd Włókienniczy − Włókno, odzież, skóra, 2009, 63, (6−7), pp. 57−60. 2 2 2 2 t R  t  t  t 18. Józkowicz I., Włochowicz A., Drobina R., H CVm Neps200% H GQ  (2) Lewandowski S.; Przegląd Włókienniczy tR tCV tNeps t ( H )2  ( m )2  ( 200% )2  ( H )2 − Włókno, odzież, skóra, 2009, 63, (9), W W W W pp. 43−45. i ' i ' iNeps' iH ' RH CVm 200% 19. Lewandowski S., Drobina R.; Fibers Text. East. Eur., 2004, 12, No. 2 (46), Equation 2. pp. 31−37.

24 FIBRES & TEXTILES in Eastern Europe 2010, Vol. 18, No. 4 (81) 20. Lewandowski S., Drobina R.; Fibers Text. East. Eur., Part I, 2008, 16, No. 5 (70), pp. 33−39, Part II, 2008, 16, No. 6 (71), pp. 20−27. We take pleasure in inviting you to 21. Lewandowski S., Drobina R., Kasztelnik A.; Informator Bawełny, 2008, No. 2, pp. the next XIPS Conference, 45−60. th 22. Lewandowski S., Drobina R., Kasztelnik The 8 in a series of meetings on X-Ray Investigation A.; 2008, Informator Bawełny, No. 3, pp. of Polymer Structure 31−41. 23. Malinowski M. i inni; Laboratorium z przędzalnictwa – ćwiczenia rachunkowe, cz. I, Skrypty dla Szkół Wyższych, Poli- technika Łódzka – Łódź, 1994. XIPS’2010 24. Mańczak K.; Metody identyfikacji wielo- wymiarowych obiektów sterowania, WNT Is scheduled for the beginning of December, 2010 – Warszawa, 1979. 25. Masters T.; Sieci neuronowe w praktyce, The conference covers all topics concerning polymers structure inves- WNT Warszawa, 1996. 26. Nikolić M., Stjepanovič Z., Lesjak F., tigations with X-rays, including various fields such as X-ray crystallogra- Štritof A.; Fibers & Text. East. Eur., 2003, phy, wide angle (WAXS) and small angle (SAXS) X-ray scattering as Vol. 11, No. 4 (43) pp. 30-35. well as novel methods, and instrumentation related to these methods. 27. Omeroglu S., Ulku S.; Fibers & Text. East. Scientists using the neutron scattering method (SANS) are also wel- Eur, 2007, Vol. 15, No. 1 (60) pp. 39-42. come. The previous conference XIPS’07, organised in Cracow, was at- 28. Özdil N., Özdoğan E., Demirel A., Öktem tended by 75 distinguished scientists from European universities and T., Fibers & Text. East. Eur., 2005, Vol. 13, No. 2 (50) pp. 39-43. scientific institutions. 29. Peters G.; The correlation between fiber neps and yarn neps, the fiber process It is a great pleasure to extend to you our invitation to participate in this control, USTER think quality, USTER Conference TECHNOLOGY AG, 2006. 30. Polański Z.; 2000, www.statsoft.pl/czytel- nia/jakosc/planowdosw.html. 31. Rieter Textiles Systems, 2003, www. rieter.com. 32. Ring Spinning Machines, K45, 2004, ComforSpin machine, Rieter Machine Works Ltd., www.com4.ch. 33. Sette S., Boullart L., Van Langenhove L., Kiekens P.; Text. Res. J., 1997, 67, (2), pp. 84−92. For further information please contact: 34. Stanisz A.; „Przystępny kurs statystyki na przykładach z medycyny z wykorzy- staniem programu STATISTICA”, t. I i II, The Chairman of the Conference wyd. II, Statsoft, Kraków, 2006. 35. Taskin C., Ozguney A.T., Gurkan P., Prof. Jarosław Janicki, Ph.D., D.Sc. Ozcelik G., Ozerdem A.; Fibers & Text. East. Eur., 2007, Vol. 15, No. 1 (60) pp. tel. +48 33 8279 114, fax. +48 33 8279 100 86-90. e-mail: [email protected] 36. Yeşilpınar S.; Fibers & Text. East. Eur., 2006, Vol. 14, No. 2 (56) pp. 20-23. or 37. Lewandowski S.; Modelowanie i klasy- fikacja połączeń końców przędz przy The Secretary of the Organizing Committee użyciu sztucznych sieci neuronowych, Rozprawy Naukowe nr 26, ISSN 1643- Prof. Stanisław Rabiej, Ph.D., D.Sc. 983-X, 2009. 38. Drobina R.; Ocena zaplatanych połączeń tel. +48 33 8279 159, fax. +48 33 8279 100 końców przędz, rozprawa doktorska, e-mail: [email protected] Akademia Techniczno Humanistyczna, Bielsko-Biała, 2007. 39. Józkowicz I.; Analiza porównawcza University of Bielsko- Biała przędzenia obrączkowego klasycznego Faculty of Materials and Environmental Sciences i kompaktowego, rozprawa doktorska, Akademia Techniczno Humanistyczna, Institute of Textile Engineering and Polymer Materials Bielsko-Biała, 2009. ul. Willowa 2, 43-309 Bielsko-Biała, Poland

Received 30.11.2009 Reviewed 07.06.2010

FIBRES & TEXTILES in Eastern Europe 2010, Vol. 18, No. 4 (81) 25