Indian Journal of Engineering & Materials Sciences

CONTENTS

Indian Journal of Engineering & Materials Sciences

Vol. 12, April 2005, pp. 91-96

Burr size minimization in drilling using Taguchi technique

V N Gaitonde, B T Achyutha  & B Siddeswarappa

 Burr formation in drilling is one of the serious problems in precision engineering and mass production. The exit burr degrades the precision of products and causes additional cost of deburring. Since deburring processes are not yet well automated, the productivity of advanced manufacturing systems is often reduced. However, these processes are labour intensive and add to the total cost of components. Therefore, understanding the drilling burr formation and its dominant parameters is essential for controlling the burr size. This paper describes the Taguchi method based robust design philosophy for minimization of burr size in drilling. Four parameters, namely, cutting speed, feed rate, point angle and clearance angle were identified and the ranges of the parameters for the present investigation was determined from preliminary experiments. Each parameter was investigated at three levels to study the non-linearity effect of the parameters. Taguchi method based L₉ orthogonal array was selected and experiments were conducted as per experimental layout plan. Based on signal to noise ratio analysis, the optimal settings of the process parameters have been determined. Confirmation tests have also been performed to predict and verify the adequacy of the additive models for determining the optimal burr size.

IPC CODE: B23B 51/00

Indian Journal of Engineering & Materials Sciences

Vol. 12, April 2005, pp. 97-103

Optimizing cutting force for turned parts by Taguchi’s parameter design approach

 Hari Singh & Pradeep Kumar

 The objective of the paper is to obtain an optimal setting of turning process parameters (cutting speed, feed and depth of cut) resulting in an optimal value of cutting force while machining En24 alloy steel (0.4%C) with TiC coated carbide inserts. The effects of the selected process parameters have been accomplished using Taguchi’s parameter design approach. The results indicate that the selected process parameters-cutting speed, feed and depth of cut, as well as the interaction between cutting speed and depth of cut significantly affect the mean and variance of cutting force of En24 steel turned parts.

IPC Code: B23G 1/00

Indian Journal of Engineering & Materials Sciences

Vol. 12, April 2005, pp. 104-110

Planar parallel manipulators: Structure based selection from the viewpoint of workspace

 A Srinath & A C Rao

 It is known that serial manipulators generate greater workspace. Recent trend is to use planar parallel manipulators where heavy loads are to be handled. There are a large number of planar parallel structures available with the same number of links and degree of freedom (d.o.f.). However, there is no quantitative measure to estimate the parallelism present in a chain. Mathematical measures are proposed to estimate parallelism that exists in a chain, since it influences the rigidity and workspace. Also, formulae are suggested to get insight of the workspace generated, i.e., well conditioned or not.

IPC Code: B25J

Indian Journal of Engineering & Materials Sciences

Vol. 12, April 2005, pp. 111-116

 A robust approach for evaluating modulus of elasticity of pavement concrete

Sinan Hınıslıoğlu & Osman Ünsal Bayrak

This paper presents the results of an experimental investigation carried out to optimize the modulus of elasticity of pavement concrete by Taguchi method. The experiments have been designed using orthogonal array technique in L₁₆ array with four factors and four levels each. Factor levels are 0.30, 0.35, 0.40 and 0.45 water/binder ratio, four different types of gradation with maximum aggregate size of 32 mm, 0, 5, 10 and 15% fly ash and 0, 10, 20 and 30% silica fume replacement by weight of cement. The response data have been analyzed using analysis of variance (ANOVA) technique. According to ANOVA table, water/binder ratio and fly ash content play significant role on modulus of elasticity of concrete pavement. Moreover, the optimum conditions are found to be 0.30 water/binder ratio, gradation Type IV (70% coarse aggregate, 30% fine aggregate), 5% FA content and 20% SF contents. Maximum modulus of elasticity of 33 GPa has been achieved at the optimum conditions. In addition, it is shown that Taguchi method can be used in a pavement concrete mix design as an alternative to the conventional design method.

IPC Code:E01C 3/02

Indian Journal of Engineering & Materials Sciences

Vol. 12, April 2005, pp. 117-121

 A study of applying nested hyper-rectangle learning model to concrete strength estimation

 Li Chen

 The aim of this paper is to demonstrate an exemplar-based nested hyper-rectangle learning model (NHLM) and apply it to estimate the strength of high performance concrete (HPC). The proposed model is based on the concept of seeding training data in the Euclidean i-space (where i denotes the number of features) as hyper-rectangles. The well-designed structures and one-shot learning procedures of NHLM could adjust learning abilities efficiently when new examples are added. HPC is a highly complex material, which makes modelling its behaviour a very difficult task. Compared with a standard back-propagation neural network (BPN), the experimental results indicate that NHLM provides a powerful tool for estimating the strength of HPC.

IPC Code: C04B14/00

Indian Journal of Engineering & Materials Sciences

Vol. 12, April 2005, pp. 122-128

Solar photocatalytic oxidation and removal of arsenic from ground water

Ayan Majumder & Malay Chaudhuri

In a laboratory study, the effectiveness of combined tartrate and citrate as photocatalyst in solar photocatalytic oxidation and removal of arsenic from ground water was studied and a method, using a naturally occurring tartrate-citrate photocatalyst that can be used at the household level to treat small quantities of drinking water was developed. Kinetic tests performed with 250 mg/L As(III)-spiked ground water in presence of 5 mg/L Fe(II) and 50 mM photocatalyst, showed equal efficiency of tartrate and citrate in combination for oxidation and removal of arsenic from ground water in 6 h solar illumination. Presence of silicate moderately decreased the removal of arsenic, while phosphate had more drastic effect on arsenic removal. With the increase in initial As(III) concentration above 250 mg/L, 5 mg/L Fe(II) did not achieved the removal to below 50 mg/L, although the maximum removal efficiency was 80%. Extract of tamarind (fruit of the tree Tamarindus indica), a natural source of tartrate-citrate (equivalent to 50 mM tartrate and citrate) achieved the arsenic oxidation and removal from 250-260 mg/L arsenic-bearing water to below 50 mg/L. The method performed within a 1-L closed PET bottle showed similar removal and can be applied at the household level to treat small quantities of drinking water.

IPC Code: C02F

Indian Journal of Engineering & Materials Sciences

Vol. 12, April 2005, pp. 129-140

Free asymmetric transverse vibration of polar orthotropic annular sector plate with linearly varying thickness in the radial direction

 R P Singh & S K Jain

 In the present paper, free asymmetric transverse vibration of a non-uniform polar orthotropic annular sector plate with a linearly varying thickness in the radial direction have been studied on the basis of classical plate theory when the circular edges of the plate are elastically restrained against translation and rotation while straight (radial) edges are simply-supported. The fourth order linear differential equations with variable coefficients governing the motion have been solved by using collocation technique with Chebyshev collocation points as the interpolating nodes. Frequency parameters of the plate with flexible boundary conditions at the circular edges for some typical values of the taper parameters, the rigidity ratios and the radii ratio have been presented.

IPC Code: B06B

 Indian Journal of Engineering & Materials Sciences

Vol. 12, April 2005, pp. 141-150

 Formability of HSLA and EDDQ steels of tube products of India

R Narayanasamy  & C Sathiya Narayanan

In this work, the formability of HSLA (micro alloyed steel of 1.6 mm thickness) and EDDQ (1.2 mm thickness) steels have been studied and the suitability of HSLA and EDDQ steels for forming applications have been examined. The experimental work on microstructural aspects, tensile properties and formability parameters were carried out for both the steel sheet metals. The forming limit diagram for EDDQ and HSLA steels have been experimentally evaluated. A detailed analysis of the strain distribution profiles obtained from experiment has been attempted. The fracture surfaces of the formed samples have been observed using scanning electron microscopy with a view to obtain a correlation between fracture behaviour and formability of the sheet metals. The EDDQ steel has been found to possess good drawability and stretchability, whereas the HSLA steel has been found to possess limited drawability and stretchability.

IPC Code: C22C 38/00

Indian Journal of Engineering & Materials Sciences

Vol. 12, April 2005, pp. 151-154

 Preparation of ferrites from the combustion of metal nitrate-oxalyl dihydrazide solutions

 B S Randhawa, H S Dosanjh & Manpreet Kaur

 Spinel ferrites, MFe₂O₄ (M= Co, Ni, Cu, Zn) have been prepared by a redox chemical reaction between aqueous solutions of metal nitrates, ferric nitrate and oxalyl dihydrazide (ODH). On rapid heating the reaction mixture undergoes an abrupt exothermic redox chemical reaction that facilitates atomic scale mixing of the cations. This leads to the formation of stoichiometrically pure and single-phase nanoparticle ferrites at comparatively reduced temperature (400^oC) and in less time than possible by the conventional ceramic method. The final thermolysis products (ferrites) have been characterized by various physico-chemical techniques, i.e., XRD, IR, SEM and magnetic studies (saturation magnetization and Curie temperature).

IPC Code: C22B

Indian Journal of Engineering & Materials Sciences

Vol. 12, April 2005, pp. 155-157

 Variable temperature oblique incidence reflection microscopy (VTOIRM) studies on (110) face of palmitic acid crystals

 P B Shashikanth, K Rajgopal, Beniyam Beyene & P B V Prasad

 Modifications noticed in the (110) face of palmitic acid crystals, due to slow heating, detected by VTOIRM, is interpreted in terms of two phase transitions, WBB (weak bond breaking) and SBB (strong bond breaking) promoted by anisotropy in interaction energies.

IPC Code: C30B

Indian Journal of Engineering & Materials Sciences

Vol. 12, April 2005, pp. 158-164

 Correlations for predicting detonation temperature of pure and mixed CNO and CHNO explosives

M H Keshavarz

 In this paper, detonation temperature of CNO and CHNO explosives is evaluated by the base of atomic composition and heat of formation. It is shown here how only atomic composition and condensed phase heat of formation of CNO and CHNO explosives are sufficient for reliable prediction of detonation temperature as compared to complicated computer codes. New correlations are introduced so that they can easily be applied for determining detonation temperature via specified different pathways of decomposition of explosives. Calculated detonation temperatures by this procedure for both pure and explosive formulations show good agreement with respect to measured and the BKWS-EOS predictions of detonation temperatures.

IPC Code: C06B 25/00