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Indian Journal of Engineering & Materials Sciences

 

ISSN : 0971-4588   CODEN : IEMSEW
VOLUME 10

NUMBER 3

JUNE 2003

 

CONTENTS

 

Engineering

 

A simple method to predict the thermal post-buckling behaviour of columns on Pasternak foundation

177

G Venkateswara Rao & K Kanaka Raju

 

 

 

Computation of vibration frequencies of plate structures

183

S Chakraverty

 

 

 

A new charge-pump PLL for tracking bursty signals

189

M K Mandal & B C Sarkar

 

 

 

Calibration of structural cracking models for asphalt pavements: HDM-4 case

193

Hernan de Solminihac, Priscila Hidalgo, Mauricio Salgado & Anibal Altamira

 

 

 

A new algorithm for back-calculating flexible pavement layer moduli

202

Mehmet Saltan

 

 

 

Materials Science

 

 

 

Influence of modifiers on optical properties of ZnF2-TeO2 glass system doped with Eu3+ ions

207

C Laxmi Kanth, B Appa Rao & N Veeraiah

 

 

 

Optical studies and laser parameters of various Pr3+ doped glass systems

215

Y K  Sharma, S S L Surana, C L Gehlot & S P Tandon

 

 

 

Behaviour of low heat sulphate resistant cement in aggressive media

219

Manjit Singh & Mridul Garg

 

 

 

Galvanostatic electrodeposition of Ti-(CdGa)Se films and their photoelectrochemical characterization

 223

M L Srivastava & Sameer S D Mishra

 

 

 

An intentation and stress analysis of WC/Fe-Mn hardmetals

229

S C Hanyaloglu, B Aksakal & S Sen

 

 

 

Simple method for predicting detonation pressure of CHNO mixed explosives

236

M H Keshavarz & M Oftadeh

 

 

 

Book Review

 

 

 

Practical density measurement and hydrometry

239

by S V Gupta; reviewed by R S Beniwal

 

 

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 10, June 2003, pp. 177-182

 

 

A simple method to predict the thermal post-buckling behaviour of columns on Pasternak foundation

G Venkateswara Rao & K Kanaka Raju

 

A simple, intuitive method is presented in this paper to predict the thermal post-buckling behaviour of uniform columns with axially immovable ends on a two parameter Pasternak foundation. Both the simply supported and clamped columns are considered in this study. To bring out the simplicity of the method, a rigorous variational solution (Rayleigh-Ritz method) is also presented, which involves the difficulty of assuming an appropriate admissible function for the axial displacement compatible with the lateral displacement. In this method, the axial displacement distribution is not required, which makes it very simple and attractive. It gives exactly the same results as that of the rigorous variational solution for the thermal post-buckling behaviour. Numerical results in terms of the post-buckling load parameter to the linear buckling load parameter are presented, which are directly useful to the designers and analysts.

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 10, June 2003, pp. 183-188

 

 

Computation of vibration frequencies of plate structures

S  Chakraverty

 

This paper introduces a new concept to get vibration characteristics directly without solving the plate equation of motion. It uses the data as obtained from literature in particular from the author’s previous studies and then proposes direct equations to fit in the data, which can give the desired frequencies. The reliability and efficiency of the equations have been tested and are compared with the results from the usual traditional method of solution.

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 10, June 2003, pp. 189-192

 

 

A new charge-pump PLL for tracking bursty signals

M K Mandal & B C Sarkar*

 

A charge pump phase locked loop comprising of a ring oscillator has been proposed to extract continuous carrier signal from burst like input signal. Experimental studies confirm that the simple structural modification provides a fairly steady reconstructed carrier signal.

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 10, June 2003, pp. 193-201

 

 

Calibration of structural cracking models for asphalt pavements: HDM-4 case

Hernán de Solminihac, Priscila Hidalgo, Mauricio Salgado & Aníbal Altamira

 

The HDM-4 (Highway Development Management) models used for pavement management activities must be adapted to specific conditions of the country or region where they are to be used by adjusting certain calibration factors. This work presents results obtained from the calibration of structural cracking models in HDM-4 version 1.1, and comparing the results from equivalent HDM-III models. The “windows” methodology is used to reconstruct the distress performance curve of a specific road category based on the observation of conditions of diverse roads with similar characteristics (such as traffic, pavement structural capacity and climatic conditions) but different ages. Also, recommendations are made for calibrating performance models, as well as for establishing calibration factors for asphalt pavement structural cracking models more appropriate for Chilean roads. Although the results of the HDM-III and HDM-4 calibrated models have similar values, the HDM-4 version 1.1 cracking models are recommended due to their operational advantages.

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 10, June 2003, pp. 202-206

 

 

A new algorithm for back-calculating flexible
pavement layer moduli

Mehmet Saltan

 

In this paper, a new algorithm for backcalculating pavement layer moduli from pavement deflection basin is presented. The algorithm uses SDUFEM finite element based backcalculation program in the iterative process and adopts backcalculating pavement layer moduli at fixed Poisson’s ratios. After forward calculation for surface deflections at specific points is made with known elastic properties, flexible pavement layer moduli are backcalculated using new algorithm.

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 10, June 2003, pp. 207-214

 

 

Influence of modifiers on optical properties of ZnF2-TeO2 glass system doped with Eu3+ ions

C Laxmi Kanth, B Appa Rao & N Veeraiah

 

ZnF2-MO-TeO2 (MO = PbO, ZnO and CdO) glasses doped with Eu3+ ions have been prepared and samples are characterized by X-ray diffraction and differential scanning calorimetric studies. Optical absorption, photoluminescence, infrared spectra and thermoluminescence studies have been carried out; from the measured intensities of various absorption bands of these glasses the Judd-Ofelt parameters W2, W4 and W6 have been evaluated. The Judd-Oflet theory could successfully be applied to characterise the absorption and luminescence spectra of these glasses. From this theory various radiative properties like transition probability A, branching ratio br, the radiative life time tR and the emission cross-section sE for various emission levels of these glasses have been determined and reported. The analysis of these results with the aid of IR spectra and thermoluminescence studies, it has been identified that CdO mixed tellurite glass as the most favourable host for Eu3+ doping and to give high luminescence efficiency.

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 10, June 2003, pp. 215-218

 

 

Optical studies and laser parameters of various Pr3+ doped
glass systems

Y K Sharma, S S L Surana, C L Gehlot & S P Tandon

 

Absorption and fluorescence spectra have been studied in the range (400-2400 nm) and (400-800 nm) respectively of twelve glass specimens of Pr3+ doped (doping concentration 0.1 and 0.2 mol%) borophosphate, zinc chloride borophosphate, aluminoborophosphate, chlorophosphate, phosphate and borate glass systems. The specimens of glass systems have been prepared by melt quenching technique. Judd-Ofelt parameters (Wl) evaluated using the observed spectral intensities have been used to calculate various laser parameters, viz., spontaneous emission probability (A), radiative life time (t), fluorescence branching ratio (b) and stimulated emission cross-section (sp) for the three different laser transitions 3P0 ® 3H4 (485 nm), 3P0 ® 3H6 (599 nm) and 3P0 ® 3F2 (641 nm). A comparative study of laser parameters for the various types of glasses shows that aluminoborophosphate (ALBP) glasses are better for the laser transition 3P0 ® 3H4 whereas for the laser transitions 3P0 ® 3H6 and 3P0 ® 3F2, borophosphate (BP) and zinc chloride borophosphate (CLBP) glasses respectively are much better than the other glasses studied. sp values for CLBP glasses for the laser transition 3P0 ® 3F2 show a considerable increase (by a factor of ~ 2.5) over the sp values for the same transition in phosphate and chlorophosphate glasses.

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 10, June 2003, pp. 219-222

 

 

Behaviour of low heat sulphate resistant cement in
aggressive media

Manjit Singh & Mridul Garg

 

The low heat sulphate resistant (LHSR) cement has been produced by activation of granulated blast furnace slag with low temperature phase of gypsum, i.e., calcium sulphate hemihydrate (CaSO4. ½ H2O) produced at 150°C. The LHSR cement was tested and evaluated as per IS: 4031 - 1995 and the properties compared with ordinary portland cement (OPC). The LHSR cement on hydration produce ettringite, C-S-H and C4AH13 as the major hydraulic products. The suitability of LHSR cement was examined for its use in sulphate solutions such as Na2SO4.10H2O, (NH4)2SO4, MgSO4 and in mixture of NaCl and Na2SO4.10H2O. Data up to 90 days of curing in sulphate solution is reported. The results show that with curing, a fall in compressive strength of LHSR cement as well as OPC took place. However, the fall of strength was lower in LHSR cement than the OPC. The attainement of higher strength values in LHSR cement in sulphate solutions may be correlated with the formation of increased quantity of C-S-H and decrease in Ca(OH)2 and ettringite. The LHSR cement may be used in construction work to obviate sulphate attack.

 

    

 

Indian Journal of Engineering & Materials Sciences

Vol. 10, June 2003, pp. 223-228

 

 

Galvanostatic electrodeposition of Ti-(CdGa)Se films and their photoelectrochemical characterization

M L Srivastava & Sameer S D Mishra

 

Titanium supported gallium containing CdSe films have been prepared using electrodeposition technique. The photoelectrochemical characterization of these Ti-(CdGa)Se films has been carried out on the basis of their photoelectroconvertibility and photoaction spectral studies. Current voltage behaviour of the electrodeposited films was also investigated to construct Tafel plots for the purpose of electrochemical corrosion.

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 10, June 2003, pp. 229-235

 

 

An indentation and stress analysis of WC/Fe-Mn hardmetals

S C Hanyaloglu, B Aksakal & S Sen

 

Vickers indentation has been applied experimentally to the produced hardmetal, WC-Fe 13.5 wt% Mn. It has been observed that the Palmqvist type cracks occur on the substrate hardmetal. The mechanical examination prove that the produced alloy possesses higher hardness, and unavoidably a bit lower fracture toughness than the equivalent of cobalt bonded grades. This could lead such hardmetal alloys to be used in mining and wear-resistant applications with better reliability. Three-dimensional stress analysis has been conducted using the finite element method on the basis of elastic failure due to brittleness of the material showing ignorable plastic deformation.

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 10, June 2003, pp. 236-238

 

 

Simple method for predicting detonation pressure of
CHNO mixed explosives

M H Keshavarz & M Oftadeh

 

A simple method is presented to estimate the detonation pressure of mixed CHNO explosives at various loading densities. This method is based upon a simple correlation in which the detonation pressure is interrelated by estimated gaseous detonation products and combustion temperature. Heat of formation calculated by semi-empirical PM3 procedure is used to calculate the combustion temperature. Calculated detonation pressure for known mixtures of CHNO explosives give results in better agreement with  measured values than complicated BKW-EOS computer code.

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 10, June 2003, pp. 239-240

 

 

Book Review

 

Practical Density Measurement and Hydrometry, by S V Gupta (Institute of Physics Publishing, Philadelphia), ISBN 0750308478, Price $115.00, Hard-bound pages 352 + xx, June 2002. The book brought out by the Institute of Physics under `Series in Measurement Science and Technology’ (Series editor M Afsar, Tuffs University, USA), provides details of the latest and most precise developments and methods in density measurement and gives descriptions of practical use with state of the art techniques and equipment.