Subhash Nimanpure; S. A. R. Hashmi; Rajnish Kumar; Archana Nigrawal; H.N. Bhargaw; Ajay Naik
Abstract
Environment friendly electrical insulation material was developed using bio based rectangular cross sectioned sisal fibrils as reinforcement. High content cellulose base fibrils fibrillated by mechanical disintegration method into macro and micro fibrils from coarse sisal fibre. This fibrils were randomly ...
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Environment friendly electrical insulation material was developed using bio based rectangular cross sectioned sisal fibrils as reinforcement. High content cellulose base fibrils fibrillated by mechanical disintegration method into macro and micro fibrils from coarse sisal fibre. This fibrils were randomly distributed in polymer matrix. These composites were characterized in term of electrical, mechanical and thermal properties to investigate the stability for high strength electrical insulation materials. Excellent mechanical properties were observed. Tensile, flexural and impact strength of composites at 40 wt. % fibril loading improved by 151.34, 197.43 and 360.07 % as compared to unsaturated polyester resin. A few micro-mechanical models were compared with the experimental values. Nielson-Chen Model predicted the experimental data most accurately. The electrical properties of surface modified sisal fibril composites improved significantly in higher frequency. DSC analysis showed that the decomposition temperature of composite was higher, around 22°C than that of the polyester resin. Thermal degradation reduced and was observed in the range of 83-87% of fibril composites as compared to 97% of resin. Fibril composites are highly sensitive to electrical frequency and exhibit excellent electrical insulation property at 20 kHz. Alkali treated fibril based composites resulted an environment friendly thermally stable, high strength insulation material. Copyright © 2018 VBRI Press.
Meena Kumari; Manju Sikarwar; U.P. Verma
Abstract
In this paper DyMg alloy has been studied in three phases viz. B1, B2 and B3. The exchange correlation potential within the generalized-gradient approximation (GGA) of projector augmented wave (PAW) method is used. The predicted lattice constants and total energy at ambient condition, respectively ...
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In this paper DyMg alloy has been studied in three phases viz. B1, B2 and B3. The exchange correlation potential within the generalized-gradient approximation (GGA) of projector augmented wave (PAW) method is used. The predicted lattice constants and total energy at ambient condition, respectively in B1, B2 and B3 phases are 6.395, 3.772, 6.40 Å, and -24734.778, -24734.855, -24734.683 Ry. From the calculations it is evident that ground state phase of DyMg is B2, therefore, other parameters such as the bulk modulus, its pressure derivative, elastic constants and thermal properties related to B2 phase are presented in this paper. The obtained results are compared with the available experimented and theoretical data. The calculated band structure shows that this alloy no band gap. In order to obtain more information about the elastic properties other parameters such as Zener anisotropy factor, Poisson ratio, Young’s modulus and isotropic shear modulus are also presented. Thermal parameter such as Debye temperature, specific heat, Gruneisen parameter etc. has been determined as a function of pressure and temperature. Copyright © 2017 VBRI Press.
Hemalata Jena; Arun Kumar Pradhan; Mihir Kumar Pandit
Abstract
The present study attempts to explore the possibilities of utilising industrial waste as filler material in bamboo fibre reinforced composites. Cenosphere, a mixture of alumina and silicon rich industrial waste produced during burning of coal in thermal power plants, is used as filler material in this ...
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The present study attempts to explore the possibilities of utilising industrial waste as filler material in bamboo fibre reinforced composites. Cenosphere, a mixture of alumina and silicon rich industrial waste produced during burning of coal in thermal power plants, is used as filler material in this study. It's use in composites would address environmental and economic concern arising in storage and handling of enormous quantity of waste discharged by the thermal power plants. In order to determine the heat insulation property of this polymer composites with varying bamboo fibre (18, 28, 33, 43 wt%) and cenosphere filler (0, 2.5, 3, 4.5, 6 wt%) content, thermal conductivity test is performed by using Lee’s disc apparatus. Experimental results reveal that with the increase in fibre loading, the thermal conductivity of the composite decreases and it is minimum at 43 wt% of fibre. It is also found that introduction of cenosphere fillers on bamboo fibre reinforced composite results in further reduction of its thermal conductivity. Hence improved thermal insulation property of these composites can be gainfully utilised in insulation application. The thermal conductivity of these composites is also evaluated by using Finite Element Method, which is in good agreement with that of experimental results. The test results for thermal conductivity are also in good agreement with various models available in the literature. Copyright © 2017 VBRI Press.
