http://nopr.niscair.res.in/handle/123456789/290 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/423 Title: Theoretical evaluation of warp tension variations during weaving process <br/> <br/>Authors: Sheikhzadeh, M; Hosseini, S A; Darvishzadeh, M <br/> <br/>Abstract: The relationship between the ratio of the applied force on warp yarn by backrest roller to the warp tension, and the radius of backrest roller, the vertical position of backrest roller and the horizontal position of backrest roller with variations in warp beam radius during weaving process has been studied. The optimum values of the parameters have been calculated using a computer programme with the aim to minimize the variation in warp yarn tension during weaving process from full to empty warp beam. The results show that the increase in vertical distance between backrest roller and warp beam radius of backrest roller and horizontal distance between backrest and warp beam towards inner side causes lower variation in the ratio of force applied on warp sheet by backrest roller and warp tension during weaving <br/> <br/>Page(s): 377-380 Wed, 29 Aug 2007 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/422 Title: Thermal behaviour and structural features of chemically and bio-chemically modified jute substrate <br/> <br/>Authors: Samanta, Ashis Kumar; Singhee, Deepali; Basu, Gautam; Biswas, Santosh Kumar <br/> <br/>Abstract: Effects of NaOH treatment, conventional hot H₂O₂ bleaching, H₂O₂ and K₂S₂O₈ combined room-temperature bleaching, mixed enzyme treatment and N-methylol resin finishing on thermal behaviour and structural features of jute substrate have been studied. Differential scanning calorimetric study under nitrogen cover reveals distinct peaks for thermal degradation of cellulose, hemicellulose and lignin components of chemically and bio-chemically modified jute, showing some positive or negative shifts of thermal degradation temperatures for each of the three major constituents of jute owing to alkaline / oxidative or enzymolytic degradation or resinification of the jute components. Thiourea formaldehyde (TUF)-resin treatment renders the jute substrate with maximum thermal stability. There is a measurable increase in the crystallinilty percentage for 1-5% NaOH treatment, and the same is decreased on oxidative or enzyme treatment and remains almost unaffected for AMF-resin or TUF-resin treatment. Observed chemical changes / interactions have been explained by the analysis of FTIR spectra and copper number of differently treated jute substrate. Higher copper number is observed for room-temperature bleaching than that for conventional H2O2 bleaching. Changes in the overall surface morphology of the treated fabrics have also been characterized by scanning electron microscopic study. Room-temperature bleaching followed by mixed enzyme treatment shows maximum surface cleanliness with a smooth and less hairy surface appearance. Both AMF-resin and TUF-resin treatments show a surface coverage with a resin film. <br/> <br/>Page(s): 355-365 Wed, 29 Aug 2007 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/421 Title: Microencapsulation of herbal extracts for microbial resistance in healthcare textiles <br/> <br/>Authors: Thilagavathi, G; Bala, S Krishna <br/> <br/>Abstract: Antimicrobial finish has been imparted to the cotton fabric using extracts of neem and Mexican daisy by direct application and by microencapsulation using pad-dry-cure method. To enhance the durability of antimicrobial finish to number of washes, the microencapsulation of herbal extracts has been done using phase separation / coacervation. Microcapsules are produced using herbal extracts as core and acacia as wall material. Structure of microcapsules has been evaluated using light microscopy with image analysis technique, the presence of microcapsules by scanning electron microscopy, the antimicrobial efficacy by quantitative method in terms of bacterial reduction, and the wash durability of antimicrobial activity by AATCC 124. It is observed that the microencapsulated herbal extracts possess a very good resistance for microbes even after 15 washes. <br/> <br/>Page(s): 351-354 Wed, 29 Aug 2007 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/420 Title: Tensile properties of cotton yarns after slack swelling and stretching in presence and absence of sodium hydroxide <br/> <br/>Authors: Hebsiba, G Anita; Thambidurai, S <br/> <br/>Abstract: The properties of ring- and rotor-spun cotton yarns subjected to combined swelling and stretching in presence and absence of aqueous sodium hydroxide (21%w/w) at pre-determined time intervals have been studied. Yarns stretched in the solution exhibit spectacular changes in their properties. The increment in shrinkage values is found to be more in slack swollen rotor-spun yarns as compared to that in ring-spun yarns. Crystallinity values show a decreasing trend with the increase in swelling time. Yarns stretched in solution show a tremendous increase in packing fraction. Tenacity and elongation values show significant increase with the solution stretch. The values of packing fraction, tenacity and per cent elongation are found to be higher in the case of ring-spun yarns. Scanning electron microscopy proves the swellability and packing of fibres in the yarns. <br/> <br/>Page(s): 284-289 Wed, 29 Aug 2007 22:58:59 GMT