Indian Journal of
Engineering & Materials Sciences

 

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VOLUME 15

NUMBER 4

AUGUST 2008

CODEN: IEMSEW

ISSN: 0971-4588

CONTENTS

Engineering  

Effects of process parameters on mechanical properties of friction stir welds using design of experiments

293

N Rajamanickam & V Balusamy

 

Effect of micro and macro pits of journal surface on radial pressure distribution of journal bearing

300

Cem Sinanoğlu, Fehmi Nair & Ercan Gökşen

 

Adaptive control in high speed machining for improved surface finish

311

B Giriraj, R Gandhinadhan, V Prabhu Raja & T Vijayaraghavan

 

Effect of swirl on the flow characteristics of S-shaped diffusing duct                                    

317

R B Anand, S N Singh & Lajpat Rai

 

Behaviour of simply supported steel reinforced SIFCON two way slabs in punching shear

326

H Sudarsana Rao, K Gnaneswar & N V Ramana

 
   
Materials Science  

SHI irradiation induced nano scale surface micro-relief’s in the polar (010) cleavage of pure and doped TGS crystals

334

P K Bajpai, Deepak Shah & Ravi Kumar

 
Evaluation of different consolidation methods for nano-materials                                            343

Soumen Kar, E Sriram Sarma, V B Somu, N K Kishore & V Srinivas

 
Studies on dielectric properties of a conducting polymer nanocomposite system                      347

Saumya R. Mohapatra, Awalendra K Thakur & R N P Choudhary

 
Influence of temperature stability on sensing properties of SAW NO sensor                         352

Namrata Dewan, Divya Haridas, Swati Shandilya, K Sreenivas & Vinay Gupta

 
Structural and optical studies on texture LiNbO3 thin film on (0001) sapphire                          355

Swati Shandilya, K Sreenivas, R S Katiyar &Vinay Gupta

 

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 15, August 2008, pp. 293-299

 

 

Effects of process parameters on mechanical properties of friction stir welds using design of experiments

N Rajamanickam & V Balusamy

 

Friction stir welding is a relatively new joining process that is presently attracting considerable interest. This paper aims at establishing a relationship between welding parameters and mechanical properties in welding of 2014 type aluminum alloy using friction stir welding. A plan of experiment based on full factorial design has been performed. Samples have been prepared and welded by varying input parameters such as tool rotational speed and weld speed. The analysis of variance (ANOVA) is employed to investigate the effect of input parameters on mechanical properties of weld. A correlation is established between tool rotational speed, and weld speed with mechanical properties of weld by multiple linear regression. This study indicates that weld speed is the main input parameter that has the highest statistical influence on mechanical properties.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 15, August 2008, pp. 300-310

 

 

Effect of micro and macro pits of journal surface on radial pressure distribution of journal bearing

Cem Sinanoğlu, Fehmi Nair & Ercan Gökşen

 

The aim of this study is to find the optimum journal surface micro and macro pits (pores) to improve the load carrying capacity of journal bearing. The effects of various surface porosities on pressure distribution in radial bearings have been investigated. The journals used for experiment in this paper are separated in two groups. Various surface porosities have been achieved by subjecting the surfaces of the two aluminium journals (Al-6063) in the first group (CHE-I, CHE-II) to chemical reaction (etching process). The journals in the second group (COM-I, COM-II, COM-III) have been made of metal matrix composite (MMC) with aluminium based reinforced with SiC ceramic particles, using stir casting technique. For comparison of pressure distribution with that of non-porous journal, a smooth-surfaced journal (NPJ) is used. It has been found that an optimum size and distributive range of micro and macro-pits exists, where the load carrying capacity can be increased at approximately twice over that of an un-textured surface.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 15, August 2008, pp. 311-316

 

 

Adaptive control in high speed machining for improved surface finish

 

B Giriraj, R Gandhinadhan, V Prabhu Raja & T Vijayaraghavan

 

This paper deals with development of an adaptive control system based on cutting speed correction algorithm to deliver consistent part quality in high speed machining (HSM). Rapid tool wear in HSM affects the part quality in terms of surface finish (Ra). Cutting force which is an indirect measure of surface finish is taken as input for the proposed adaptive control system. The adaptive control is implemented using the graphical programming language of LabVIEW. A process capability study is carried out with existing set-up and with adaptive control system. It was observed that, with a marginal increase in cutting speed, for a semi-dull tool, the resultant cutting force decreased and the surface finish improved. The process capability index and process capability ratio have shown 39% and 25% improvement respectively. The developed adaptive control system based on cutting speed will be an alternate to the existing feed rate correction algorithm.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 15, August 2008, pp. 317-325

 

 

Effect of swirl on the flow characteristics of S-shaped diffusing duct

R B Anand, S N Singh & Lajpat Rai

 

The flow and performance characteristics of a S-shaped diffusing duct having an area ratio of 1.9, length of 300 mm and turning angle of 22.5°/22.5° have been experimentally investigated to establish the effect of swirl.  The static pressure, total pressure, velocity and turbulence intensity are measured using a calibrated five-hole probe and constant-temperature hot-wire probe.  The performance parameters are evaluated based on the mass-averaged quantities.  A significant improvement in the pressure recovery coefficient is observed for swirl flow from 0.36 to 0.54.  The improvement is observed for both, clockwise and anti-clockwise swirl, the improvement being higher for clockwise swirl.  Flow uniformity at the exit is more uniform for clockwise swirl at the inlet.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 15, August 2008, pp. 326-333

 

  

Behaviour of simply supported steel reinforced SIFCON two way

slabs in punching shear

 

H Sudarsana Rao, K Gnaneswar & N V Ramana

 

This paper reports the behaviour of slurry infiltrated fibrous concrete (SIFCON) two-way slabs in punching shear. SIFCON slabs are cast with 8, 10 and 12% fibre volume fraction and for comparison, fibre reinforced concrete (FRC) with 2% fibre volume fraction and reinforced cement concrete (RCC) slabs are cast and tested. The results of the experimentation show that the SIFCON slabs with 12% fibre volume fraction exhibits excellent performance in punching shear among other slabs. The experimental results have been compared with the provisions of ACI and IS codes. A regression model has been proposed for estimating the punching shear strength of reinforced SIFCON slabs.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 15, August 2008, pp. 334-342

 

 

SHI irradiation induced nano scale surface micro-relief’s in the polar (010) cleavage of pure and doped TGS crystals

 

P K Bajpai, Deepak Shah & Ravi Kumar

 

The resulting image topology change as a function of irradiation is analyzed. The smooth surface of pure TGS shows pits and protrusions when irradiated with SHI beam. The height and dimensions of these micro-reliefs vary with ion beam fluence as well as with doping. The height of the pits changes from 20 nm to roughly 70 nm from pure TGS to 15% alanine doped TGS. Observed micro-relief is analyzed considering the lamellar domain structure of TGS. The domain movement induced by the internal bias field created due to irradiation results into piezoelectric compression and stretching forming these features on the surface. The results are used to calculate the internal field developed due to irradiation using the d33 and height of pits formed as reported earlier. The calculated values of internal fields are of the same order as that obtained from hysteresis measurements. This demonstrates that swift heavy ion beam irradiation could be used as a tool to modify the surface nano structures.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 15, August 2008, pp. 343-346

 

 

Evaluation of different consolidation methods for nano-materials

Soumen Kar, E Sriram Sarma, V B Somu, N K Kishore & V Srinivas

 

In the present investigation the effect of high voltage and low frequency current pulses on Ni powder compacts and on alloys like Ni80Si20 or Ni95Si5 are investigated. The pulse application on ball milled Ni powder compacts and on Ni80Si20 result in a further increase in density. This suggests that the SPS and EDC technique can be used as an alternative method for the sintering of nano-materials and for the densification of nano particles but with the simultaneous application of pressure.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 15, August 2008, pp. 347-351

 

 

Studies on dielectric properties of a conducting polymer nanocomposite system

Saumya R Mohapatra, Awalendra K Thakur & R  N P Choudhary

 

Dielectric analysis of ion conducting solid polymer nanocomposite has been investigated as a function of temperature and frequency. Effect of clay concentration in changing the dielectric relaxation behaviour of polymer salt complex film is clearly visible, observed in terms of changes in polymer chain relaxation and dipolar contribution due to ion pairs. An enhancement in relative permittivity by 2 orders of magnitude has been recorded at room temperature in nanocomposite films controlled predominantly by clay concentration. Almost similar behaviour has been observed after crystalline to amorphous phase transition temperature at T ≥70°C for both polymer salt complex and nanocomposite films irrespective of clay concentration. A lowering of relaxation time, attributed to relaxing dipoles, with clay concentration suggests faster ion dynamics in nanocomposite films.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 15, August 2008, pp. 352-354

 

 

Influence of temperature stability on sensing properties of SAW NOx sensor

Namrata Dewan, Divya Haridas, Swati Shandilya, K Sreenivas & Vinay Gupta

 

This paper presents the study on the influence of temperature stability of SAW sensor on the sensing properties for NOx gas.  Temperature stable SAW sensor based on 128o YX LiNbO3 single crystal was developed after integrating with rf sputtered amorphous TeO2 thin film that act  as a  temperature compensation over-layer.  TeO2 thin films possessing negative temperature coefficient of delay (TCD) also served as a sensing layer for the detection of NOx gas. Temperature stable SAW devices are essentially desired to avoid the problem of false alarm, besides the enhancement in the sensitivity and reliability.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 15, August 2008, pp. 355-357

 

 

Structural and optical studies on texture LiNbO3 thin film on (0001) sapphire

Swati Shandilya, K Sreenivas, R S Katiyar & Vinay Gupta

 

In this work, c-axis oriented lithium niobate thin film has been deposited on Sapphire single crystal substrate by pulse laser deposition. X-ray diffraction showed only reflections corresponding to (006) and (0012) planes of LiNbO3 on (001) sapphire substrate, indicating that growth of texture LiNbO3 film on sapphire. The estimated value of c-axis lattice parameter is found to be 1.36 nm and is close to the value reported for LiNbO3 single crystal. Optical properties of films has been studied using UV-Vis spectrophotometer and the estimated value of refractive index at 640 nm is n = 1.76 nm. A slight dispersion in the refractive index has been observed with photon energy below the interband absorption edge. Raman scattering studies made on prepared sample in the back scattering geometry with incident light normal to the film surface in Z(X+Y,X+Y)configuration indicate the formation of single phase material and free from any type of lattice defects.