Indian Journal of
Engineering & Materials Sciences

 

VOLUME 9

NUMBER 2

APRIL 2002

 

CONTENTS

 

Engineering

Neutron sensitivity improvement in boron-lined proportional counters

91

        P M Dighe, K R Prasad & S K Kataria

 

 

 

Elegant and accurate closed form solutions to predict vibration and buckling behaviour of slender beams on Pasternak foundation

98

        G Venkateswara Rao & K Kanaka Raju

 

 

 

Vibration analysis of visco-elastic clamped circular plates subjected to thermal gradient

103

        S B Singh & M Arif

 

 

 

Prediction of strength and workability of high performance concrete composites using artificial neural networks

109

        S Rajasekaran & R Amalraj

 

 

 

A numerical study on the physics of mixing in two-dimensional supersonic stream

115

        Mohammad Ali, Toshi Fujiwara & Anwar Pervez

 

Materials Science

 

Treatment of phenol rich aqueous solutions using surface modified pillared clay

128

        V P Vinod & T S Anirudhan

 

 

 

Nanocrystalline lead ruthenium pyrochlore as oxygen reduction electrode

137

        V Raghuveer, Keshav Kumar & B Viswanathan

 

 

 

Inhibition of corrosion of mild steel by nitrite, hydrogen phosphate and molybdate ions in aqueous solution of sodium chloride

141

        Rita Mehra & Aditi Soni

 

 

Influence of altered basalt on the burnability of portland cement clinker

147

        El-Sayed Ali El-Alfi

 

 

 

Effect of ambient H2S atmosphere on the optical, structural and electrical properties of vacuum deposited thin films of cadmium sulphide

153

        Virendra Singh, Beer Pal Singh, Kasturi Lal, R C Tyagi & T P Sharma

 

 

 

Performance evaluation of Ogwasi lignite coal under adiabatic condition

156

        J Soji Adeyinka & F O Akinbode

 

 

 


 


Indian Journal of Engineering & Materials Sciences

Vol. 9, April 2002, pp. 91-97

 

Neutron sensitivity improvement in boron-lined proportional counters

P M Dighe, K R Prasad & S K Kataria

 

Various techniques have been employed to improve the neutron sensitivity of boron-coated proportional counters developed indigenously. A boron-lined proportional counter (67 mm ID ´ 750 mm length) of 17 cps/nv thermal neutron sensitivity is developed by coating 92% enriched 10B on the inner wall of the counter. This counter can be used for low thermal neutron flux (~0.2 nv) at various applications such as neutron area monitoring, reactor start-up instrumentation, assay of fissile materials and detection of fuel failure. An improvement in sensitivity was also achieved by summing the output signals from four 10B lined counters and two BF3 proportional counters. The summation did not change the susceptibility of the device to gamma interference. In view of the scarcity of enriched 10B isotope, indigenously available natural boron coated two prototype proportional counters are developed of 0.8 cps/nv and 1.1 cps/nv thermal neutron sensitivity. Efforts have been made to improve the sensitivity with boron coated 3-dimensional structures introduced into the sensitive volume. Tests in thermal neutron flux showed 50% improvement in the sensitivity due to the introduction of additional boron coated wires. Another counter with 51 boron-coated annular discs (23 mm OD ´ 10 mm ID ´ 1 mm thick) mounted perpendicular to the axis of the cathode showed 1.7 cps/nv neutron sensitivity, an improvement by a factor of 2.5.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, April 2002, pp. 98-102

 

Elegant and accurate closed form solutions to predict vibration and buckling behaviour of slender beams on Pasternak foundation

 

G Venkateswara Rao & K Kanaka Raju

 

Elegant and accurate closed form solutions to predict the vibration and buckling of slender beams on Pasternak (two parameter elastic) foundation have been derived using simple single term trigonometric functions which satisfy the geometric boundary conditions in conjunction with the Rayleigh-Ritz method. Bernoulli-Euler beam theory is used for the analysis. Simply supported, cantilever and clamped boundary conditions are considered in the present study. Numerical results for the fundamental frequency and buckling load parameters are presented in the form of Tables. The present results show an excellent agreement when compared with those obtained by the versatile finite element method. An anomaly observed in the case of the buckling problem for very high first foundation stiffness parameter, is explained clearly for the case of a simply supported beam and corrective measure in terms of the mode of buckling is provided.

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, April 2002, pp. 103-108

 

Vibration analysis of visco-elastic clamped circular plates subjected to
thermal gradient

S B Singha & M Arifb

 

An analysis of vibration of visco-elastic circular plate of variable thickness subjected to thermal gradient is presented here. The governing differential equation has been solved for free vibrations of visco-elastic circular plate, which is clamped along the boundary. Galerkin’s technique has been applied to obtain corresponding natural frequencies in the form of explicit formulae. Deflection, time period and logarithmic decrement at different points for the first two modes of vibration are calculated for various types of thermal gradient and taper constant and are illustrated with tables and graphs.

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, April 2002, pp. 109-114

 

Prediction of strength and workability of high performance concrete composites using artificial neural networks

S Rajasekaran & R Amalraj

 

A model based on an Artificial Neural Network for predicting the compressive strength and workability for various mixes of High Performance Concrete (HPC) from M80 to M150 is presented. It is felt that the conventional methods of design of concrete mixes may not be suitable for HPC because, with the addition of silica fume, more water content is needed that can be eliminated by using high range water reducing admixtures for achieving the same workability. Further, the compressive strength and workability properties of HPC mixes are greatly influenced by several parameters, viz. fine aggregate, coarse aggregate, water-cement ratios, and percentage of silicafume and super-plasticizer. Consequently, developing a standard mix design procedure for HPC mixes requires an extensive understanding of relation between these parameters and the properties of the resulting mix. Developing an empirical formula for predicting the compressive strength and workability of HPC is extremely difficult because of non-linear interaction among the various parameters.

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, April 2002, pp. 115-127

 

A numerical study on the physics of mixing in two-dimensional supersonic stream

Mohammad Alia, Toshi Fujiwarab & Anwar Pervezc

 

A numerical investigation has been performed on the physics of mixing for better understanding about the penetration and mixing mechanism, and eventually to find out the means of increasing the mixing efficiency. The two-dimensional full Navier-Stokes equations with an explicit Harten-Yee Mon-MUSCL Modified-flux-type Total Variation Diminishing (TVD) scheme have been used. A zero-equation algebraic turbulence model has been used to calculate the eddy viscosity coefficient. For this study the air of Mach number 5.0 is considered as main flow. Hydrogen gas at sonic condition is injected perpendicularly into it. The effects of molecular and turbulent diffusion coefficients, and that of boundary layer on mixing have been analyzed and discussed. The results show that upstream re-circulation plays an important role to increase the mixing of side jet with the main flow of high Mach number. It has been found that the mixing is only possible by incorporating the molecular diffusion terms in the Navier-Stokes equations. The use of turbulence model increases the penetration height of hydrogen in the mixing field.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, April 2002, pp. 128-136

 

 

Treatment of phenol rich aqueous solutions using surface modified pillared clay

V P Vinod & T S Anirudhan*

 

The efficacy of humic acid treated zirconium pillared clay (HA-PILC) in the removal of phenol from aqueous solution has been investigated using batch adsorption technique at different sorbate concentrations, rate of agitation, pH and temperature. The maximum removal of 98.0, 84.0 and 73.2 % has been noted at pH 5.0 for an initial concentration of 25, 50 and 100 mg/L respectively. The maximum adsorption capacity has been observed at pH 5.0. The process of uptake follows a first-order reversible kinetic expression. The removal process has also been found to be diffusion controlled. The adsorption capacity has been increased from 78.2 to 92.6 % with an increase in agitation speed from 100 to 400 rpm at an initial concentration of 50 mg/L. The adsorption isotherm for phenol removal may be classified as L-type of the Giles classification, which suggests a favourable adsorption, and the adsorbent has a high affinity for phenol. The adsorption data points have been fitted to both Langmuir and Freundlich isotherm equations. The maximum adsorption capacity (Q0) decreases from 179.86 mg/g at 10°C to 126.69 mg/g at 40°C. Lower temperature has been found to be more effective in the removal of phenol. Thermodynamic parameters such as DG0, DH0 and DS0 for the adsorption process have been calculated to predict the nature of adsorption process. Cost of the HA-PILC and its adsorption capacity with other adsorbent materials reported in the literature, have also been presented.

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, April 2002, pp. 137-140

 

Nanocrystalline lead ruthenium pyrochlore as oxygen reduction electrode

 

V Raghuveer, Keshav kumar & B Viswanathan*

 

The synthesis of nanocrystalline Pb-Ru pyrochlore of composition Pb2Ru1.95Pb0.05O7-d was studied for the potential usage in the electrochemical reduction of oxygen. The nanocrystalline pyrochlore was synthesized by reverse micellar method. The single phase oxide formation and crystallite size determination (1-20 nm) were carried out using X-ray diffraction and transmission electron microscopic studies respectively. The electrocatalytic activity for oxygen reduction and its comparison with the oxide prepared by conventional ceramic method are also reported here.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, April 2002, pp. 141-146

 

 

Inhibition of corrosion of mild steel by nitrite, hydrogen phosphate and molybdate ions in aqueous
solution of sodium chloride

Rita Mehra & Aditi Soni

 

Inhibition of mild steel in aqueous sodium chloride by sodium nitrite, disodium hydrogen phosphate and sodium molybdate with respect to the inhibitor concentration and temperature is reported here. Na2MoO4 shows highest efficiency (90.00%) followed by NaNO2 (87.56%) and Na2HPO4 (85.36%). As such, the order of inhibition observed is Na2MoO4>NaNO2>Na2HPO4. Thermodynamic as well as kinetic parameters including activation energy (Ea), change in free energy of adsorption (DG), entropy of adsorption (DS), corrosion current (Icorr), open circuit potential (OCP), Tafel slopes (ba, bc) and threshold limiting value (TLV) for protective film formation have also been calculated from weight loss and potentiostatic polarisation methods.

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, April 2002, pp. 147-152

 

Influence of altered basalt on the burnability of portland cement clinker

El- Sayed Ali El-Alfi

 

 

Synthesis of portland cement clinker from cement raw mixes containing altered basalt was studied. The clay of the raw mix of portland cement was substituted by basalt in ratios 0, 15, 30, 45 and 60 wt.%. The ingredients of the mixes were intimately homogenized, mixed, moulded into a compact mass and fired at 1200, 1250, 1300, 1350 and 1375ēC for two hours soaking time. The burnability of each raw mix was investigated by the determination of insoluble residue, free lime contents and the phase composition of the fired products. The results show that the clinker formation was completed at 1300ēC in the presence of 30-60 wt.% basalt.

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, April 2002, pp. 153-155

 

 

Effect of ambient H2S atmosphere on the optical, structural and electrical properties of vacuum deposited
thin films of cadmium sulphide

Virendra Singh*a, Beer Pal Singha, Kasturi Lalb, R C Tyagia & T P Sharmaa

 

Evaporated thin films of cadmium sulphide have been deposited in a low ambient atmosphere of H2S (~10-4 torr). The H2S atmosphere was obtained by controlled thermal decomposition of thiourea inside the vacuum chamber. Keeping the substrates at an elevated temperature of about 200ēC helps eject any sulphur atoms deposited due to thermal decomposition of CdS during evaporation. The cadmium ions promptly recombined with the H2S to give better stoichiometry of the deposited films. The films grown by this technique have better uniformity and have better crystallinity. Apart from being more adherent to the substrates, such films are pin-holes free, which is a very vital factor in any device fabrication. The technique is applicable for all sulphide films including ZnS, PbS, CuS. Optical, electrical conductivity, X-ray diffraction and scanning electron microscope patterns are presented to show the better quality of the sulphide films deposited by this technique.

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, April 2002, pp. 156-158

 

 

Performance evaluation of Ogwasi lignite coal under adiabatic condition

J Soji Adeyinkaa* & F O Akinbodeb

 

Adiabatic condition was used to evaluate gasification of a low-grade lignite coal. Carbon boundary theory was used to evaluate CO2:CO and C:CO conversion in the bed. Temperature analysis conformed to CO:CO2 yield at 90% air factor and a carbon to carbon monoxide yield was improved by converting CO2 at the carbon boundary.