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Das S.,Central Silk Technological Research Institute
Journal of Natural Fibers | Year: 2011

The physical properties, density, and birefringence of the cocoon filament from daba (Antheraea mylitta), oak tasar (Antheraea proylei), and bivoltine mulberry (Bombyx mori) varieties were evaluated in relation to its position in different layers of the cocoon. A decrease in filament size from the outer to the innermost layers was observed in all the varieties. Though the average tenacity was found to increase in bivoltine mulberry cocoons from the outer to the innermost layers, no such specific trend was observed for daba cocoons. For oak tasar cocoons, it showed a marginal rise. A similar trend was observed for modulus also. The breaking extension was constant for daba cocoons, decreased for oak tasar cocoons, and showed a rise followed by a fall for bivoltine mulberry cocoons from the first to the last layer. However, for mulberry cocoons, it decreased fast initially up to the fourth layer and thereafter showed no change. Density showed a marginal rise at the inner layers for daba, oak tasar, and bivoltine mulberry varieties. Birefringence remains constant at outer layers and then rises for oak tasar. In case of daba cocoons, birefringence remains constant in outer and middle layers but after that there is a rise. A steady rise in birefringence values for the innermost layers was observed from the constant values of outer layers for bivoltine mulberry cocoons. © Taylor & Francis Group, LLC. Source


Shekar R.I.,Defence Bio engineering and Electro Medical Laboratory | Kotresh T.M.,Defence Bio engineering and Electro Medical Laboratory | Prasad A.S.K.,Defence Bio engineering and Electro Medical Laboratory | Rao P.M.D.,Central Silk Technological Research Institute | Kumar M.N.S.,National University of Malaysia
Journal of Applied Polymer Science | Year: 2010

Poly ether ether ketone (PEEK) polymer was extruded into filaments and cowoven into unidirectional hybrid fabric with glass as reinforcement fiber. The hybrid fabrics were then converted into laminates and their properties with special reference to crystallization behavior has been studied. The composite laminates have been evaluated for mechanical properties, such as tensile strength, interlaminar shear strength (ILSS), and flexural strength. The thermal behavior of the composite laminates were analyzed using differential scanning calorimeter, thermogravimetric analyzer, dynamic mechanical analyzer (DMA), and thermomechanical analyzer (TMA). The exposure of the fabricated composite laminates to high temperature (400 and 500°C) using radiant heat source resulted in an improvement in the crystallanity. The morphological behavior and PEEK resin distribution in the composite laminates were confirmed using scanning electron microscope (SEM) and nondestructive testing (NDT). Although DMA results showed a loss in modulus above glass transition temperature (Tg), a fair retention in properties was noticed up to 300°C. The ability of the composite laminates to undergo positive thermal expansion as confirmed through TMA suggests the potential application of glass- PEEK composites in aerospace sector. © 2010 Wiley Periodicals, Inc. Source


Das S.,Central Silk Technological Research Institute | Ghosh A.,Government College of Engineering and Textile Technology , Berhampore
Journal of Applied Polymer Science | Year: 2010

The physical properties and residual sericin content of the silk filament were evaluated in relation to its position in different layers of the cocoons corresponding to Daba (Antheraea mylitta), oak tasar (Antheraea proylei), and bivoltine mulberry (Bombyx mori) varieties. A decrease in filament linear density from the outer to the innermost layers was observed in all the varieties. Although the filament tenacity was found to increase in bivoltine mulberry cocoons from the outer to the inner layers, no such specific trend was observed for Daba cocoons. For oak tasar cocoons, it showed a marginal rise. A similar trend was observed for filament initial modulus also. The breaking extension of filament was constant for Daba cocoons, decreased for oak tasar cocoons and showed a rise followed by a fall for bivoltine mulberry cocoons from the first to the last layers. The residual sericin decreased marginally from the outer to the inner layer in the case of tasar cocoons. However, for mulberry cocoons it decreased rapidly initially up to the fourth layer and thereafter showed no change. © 2010 Wiley Periodicals, Inc. Source


Ramaiah G.B.,Central Silk Technological Research Institute | Chennaiah R.Y.,Central Silk Technological Research Institute | Satyanarayanarao G.K.,Bangalore University
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2010

Kevlar 29 is a class of Kevlar fiber used for protective applications primarily by the military and law enforcement agencies for bullet resistant vests, hence for these reasons military has found that armors reinforced with Kevlar 29 multilayer fabrics which offer 25-40% better fragmentation resistance and provide better fit with greater comfort. The objective of this study is to investigate and develop an artificial neural network model for analyzing the performance of ballistic fabrics made from Kevlar 29 single layer fabrics using their material properties as inputs. Data from fragment simulation projectile (FSP) ballistic penetration measurements at 244 m/s has been used to demonstrate the modeling aspects of artificial neural networks. The neural network models demonstrated in this paper is based on back propagation (BP) algorithm which is inbuilt in MATLAB 7.1 software and is used for studies in science, technology and engineering. In the present research, comparisons are also made between the measured values of samples selected for building the neural network model and network predicted results. The analysis of the results for network predicted and experimental samples used in this study showed similarity. © 2009 Elsevier B.V. All rights reserved. Source


Naik S.V.,Central Silk Technological Research Institute | Somashekar T.H.,Flat 302
Indian Journal of Sericulture | Year: 2013

The effect of cocoon cooking condition on cocoon filament unwinding tension, reeling characteristics and quality of raw silk has been studied in the case of Indian multi-bivoltine (Cross breed) cocoons. Cocoons were cooked to different cooking degree by adopting different cooking methods. Cocoon cooking conditions have significant correlation with reeling tension, reeling characteristics and quality of raw silk. Cocoon cooking conditions influence the swelling and softening of sericin of cocoon filament layers and crossover points in the cocoon shell and hence the filament unwinding tension. This in turn influences the reeling tension. Further, cocoon cooking conditions influence significantly the reeling characteristics and quality of raw silk. From the results, it can be inferred that under given reeling conditions, reeling tension will give an indication about the cocoon cooking conditions and this could be utilised for process control in the filatures. Further, it is observed that pressurized cooking method gives significantly better reeling characteristics and quality of silk as compared with single pan cooking method. Source

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