Indian Journal of

Using ART networks with rule extraction as a data mining tool	101
S N Sivanandam & S Sumathi

Analysis on a flexible forging cell	113
Bunyamin Aksakal

Effect of tool feed rate in single point diamond turning of aluminium-6061 alloy	123
Gufran Sayeed Khan, Rama Gopal V Sarepaka, K D Chattopadhyay, P K Jain & V M L Narasimham

Conical whirl instability of hybrid porous journal bearings in laminar lubrication regime	131
Anjani Kumar & Satinder Pal Singh

Three-dimensional free convective MHD flow and heat transfer through a porous medium	138
R N Jat & Anuj K Jhankal

Materials Science

Biosusceptibility studies on carbon fibre composites for aerospace applications	143
R B Srivastava, M C Upreti, Minu Awasthi & G N Mathur

Preparation of zinc ferrite from the thermolysis of zinc tris (malonato) ferrate(III) decahydrate	148
B S Randhawa & Manpreet Kaur

Effect of sputtering pressure on the physical properties of dc magnetron sputtered cadmium oxide films	151
T K Subramanyam, G Venkata Rao, K T Ramakrishna Reddy & S Uthannna

Substituted thiobiurets and their molybdenum and tungsten complexes as corrosion inhibitors for mild steel in 1.0 N sulphuric acid	155
R B Rastogi, M M Singh, M Yadav & K Singh

Viscous behaviour of asphaltic mixtures: Simplified fatigue test method	161
H Akbulut

Notes

Effect of annealing on spray deposited Ni-Zn ferrite thin films	166
V L Mathe & C H Bhosale

Study of electrical properties of glass thermoelectret	169
M M Upadhyay, S K Ubale & C S Adgaonkar

Using ART networks with rule extraction as a data mining tool

In this paper, two important mining tools, i.e. Neural Networks and Genetic Algorithm (GA), have been used for mining the database through pattern classification. The processing methodology consists of three major phases: Network construction and training; Pruning; Rule extraction and validation. The neural networks used are: Adaptive Resonance Theory 1.5 (ART1.5), Adaptive Resonance Theory3 (ATR3) and Multi Channel ART (MART).

The pruning phase aims at removing redundant links and units without increasing the classification error rate of the network. The pruning methods used are: Local Pruning and Threshold Pruning. The final phase extracts the classification rules from the final weights of the pruned network in the form of IF-THEN rules and rules are validated using validation algorithm. The genetic algorithm is also used to optimise the performance with regard to the various parameters used in the network. The proposed networks have been tested on letter recognition data taken from UCI machine learning site. Simulation algorithms have been implemented using C++ language in the Pentium machine. The graphical results have been obtained using Micro Soft Excel.

Analysis on a flexible forging cell

Forging and pressing in manufacturing industry has not been adapted to flexible manufacturing systems (FMS). Predictions on the metal flow and required power have been made here through the upper bound analysis by applying various amounts of deformation in an incremental manner. In order to observe the final dimensions and the structural changes during open die forging, the 6082 aluminium billets (annealed at 425°C for two hours and cooled in the air) have been subjected to cold deformation between simple flat tools. The TEM observations have been made for different parts of the locally deformed aluminium billets to show dislocation behaviour during multi-cycle cold open die forging process. Formation of a flexible forging cell (FFC), as an initial step to FMS is also described here. A simple control system is proposed to enable a communication link between computer, press and robot arm. The robot arm manipulates workpiece between upper and lower dies, where fixed on the press, to run multi compression and rotation cycles in forging of simple rectangular and square cross-section components.

Effects of tool feed rate in single point diamond turning of aluminium-6061 alloy

Gufran Sayeed Khan, Rama Gopal V Sarepaka, K D Chattopadhyay, P K Jain & V M L Narasimham

During single point diamond turning, the effects of tool feed rate on surface figure and finish of aluminium-6061 alloy are evaluated. The studies are conducted on 60 mm diameter optical flat surfaces. Twenty-six specimens are diamond turned for varying tool feed rates (0.3 mm/rev to 30.0 mm/rev) keeping all the other machining parameters constant. The aluminium surfaces thus machined, show a typical roughness of 15 nm, and surface figure of better than a half wave peak-to-valley (PV) for optimum tool feed rate. The tool feed rate between of 1.5-8.0 mm/rev is found to be optimum for a given set of other machining parameters to get the acceptable surface figure as well as roughness values. An empirical formula with best fit has been formulated to find out the practical roughness achievable for the machining conditions under study.

Conical whirl instability of hybrid porous journal bearings

in laminar lubrication regime

An analysis of conical whirl instability of an unloaded rigid rotor supported in hybrid porous oil journal bearings in laminar lubrication regime is presented here. The effect of bearing feeding parameter (b), aspect ratio (L/D), ratio of wall thickness to journal radius (H/R) and anisotropy of porous material on stability of rotor bearing system has been investigated. Higher values of b have been found to give better stability in conical whirl mode and higher stability is predicted if porous bush is considered to be isotropic.

Three-dimensional free convective MHD flow and heat transfer

through a porous medium

The three-dimensional free convective flow of an incompressible viscous and electrical conducting fluid though a porous medium in the presence of a transverse magnetic field is discussed here. It is found that magnetic field and the permeability parameter have significant effect on the flow and heat transfer.

Biosusceptibility studies on carbon fibre composites for

aerospace applications

Advanced composites are widely used as structural materials in aerospace applications. Carbon fibre reinforced composites are recognized as structural units for integral fuel tanks. The behaviour of carbon fibre composites as influenced by microbiologically induced degradation due to fuel resident microorganisms has been of considerable interest. The present study incorporates characterization of biofilm generated on carbon fibre composites due to the growth of fuel resident microorganisms in single and combination culture and their effect on the mechanical properties of carbon fibre composites. An exposure of 120 days revealed that the surface of fibre and resin matrix gets uniformly colonized by microorganisms. Aureobasidium pullulans as well as combination of cultures induced a significant (P<0.05) loss in flexural strength. However, no significant effect was recorded on flexural modulus and inter laminar shear strength properties of carbon fibre composites under the influence of fuel residing microorganisms.

Preparation of zinc ferrite from the thermolysis of zinc tris (malonato) ferrate (III) decahydrate

The thermal decomposition of zinc tris(malonato)ferrate (III) decahydrate has been investigated from ambient temperature to 600°C in static air atmosphere using various physico-chemical techniques i.e. simultaneous TG-DTG-DTA, XRD, Mössbauer and IR. After dehydration at 190°C, the anhydrous complex undergoes oxidative decomposition to yield µ-Fe2O3 and ZnO at 330°C. Subsequently the cations remix to yield fine particles of zinc ferrite, ZnFe2O4 as a result of solid state reaction between µ-Fe2O3 and ZnO at a temperature (400°C) much lower than for ceramic method. The results have been compared with those of respective oxalates.

Effect of sputtering pressure on the physical properties of dc magnetron sputtered cadmium oxide films

Polycrystalline thin films of cadmium oxide were prepared using dc magnetron sputtering technique by sputtering of metallic cadmium target in the mixture of argon and oxygen atmosphere under various sputtering pressures in the range 3×10-2-1×10-1 mbar. The variation of deposition rate of the films with the sputtering pressure was in correlation with the variation of cathode potential. The influence of sputtering pressure on the structural, electrical and optical properties of CdO films was systematically studied. The electrical resistivity of the films increased from 5.6×10-4 to 1.5×10-3 Wcm and the optical band gap increased form 2.45 to 2.53 eV with the increase of sputtering pressure from 3×10-2 to 1×10-1 mbar respectively.

Substituted thiobiurets and their molybdenum and tungsten complexes as corrosion inhibitors for mild steel in

1.0 N sulphuric acid

Corrosion inhibition studies of mild steel in 1.0 N sulphuric acid have been performed at 25ºC using substituted thiobiurets and their molybdenum and tungsten complexes as inhibitors. All the inhibitors have been found to inhibit the corrosion process by getting adsorbed on the metal surface. Among the studied thiobiurets, methoxyphenyl derivative behaved as the best corrosion inhibitor. The inhibitive properties of thiobiurets improved considerably on complexation with molybdenum and/or tungsten ions.

Viscous behaviour of asphaltic mixtures: Simplified fatigue

test method

A continuously increasing demand on roads and the need to reduce the construction costs has led to the industry requiring simplified test methods which measure the mechanical properties of bituminous materials. The method traditionally used in the industry is based on Marshal mix design, which basically determines the stability and flow test values and do not measure any fundamental property of the mix thereby pavement performance. In contrast, there are a number of key properties that can be measured to determine the mechanical properties of a bituminous mix, which are vitally important in determination of long-term performance of the mixtures. This paper describes a method, the AKAL test method, which simplifies the ITFT test and measures viscous behaviour to predict the development of permanent strain accumulation, therefore, fatigue-life and long-term performance of asphalt mixtures.

Effect of annealing on spray deposited Ni-Zn ferrite thin films

The thin films of Ni-Zn ferrite have been synthesized using spray pyrolysis technique onto the glass substrate. The as deposited films are found to be amorphous and the films become crystalline after annealing them in the temperature range 400-600oC in the steps of 100oC for 6 h. It is found that the crystallinity increases with annealing temperature. Further for the film annealed at 600oC, some additional XRD peaks of the glass substrate have been observed. Therefore, the films annealed at 500oC are characterized further by EDAX technique. The elemental analysis by EDAX confirms the stoichiometric formation of Ni-Zn ferrite. The resistivity for all the samples with respect to temperature shows rapid decrease in resistivity at around 180oC. This may be due to oxido-reduction process that appears during heating of ferrite sample in the air. 3Fe2+«2Fe3+ total reaction takes place in the temperature range 100-250oC. However, there is no much difference in the resistivity value at room temperature for these samples.

Study of electrical properties of glass thermoelectret

Thermoelectrets were prepared by applying different polarizing fields at different polarizing temperatures to the glass of composition [50ZnO-50B2O3]. The dc conductivity, dielectric constant and ac conductivity of these glass electrets were measured and the properties were found to be influenced by the polarizing field as well as temperature.

ISSN : 0971-4588		CODEN : IEMSEW
VOLUME 10	NUMBER 2	APRIL 2003