Indian Journal of
Engineering & Materials Sciences

http://www.niscair.res.in

 

VOLUME 9

NUMBER 5

OCTOBER 2002

CODEN : IEMSEW 9(5) 307-392 (2002)

ISSN : 0971-4588

 

CONTENTS

 

Engineering

 

Symmetry in planetary gear trains

311

        A C Rao & Y V D Rao

 

 

 

Instrumentation for a retarding potential analyzer for measurement of electron parameters

315

        S S Rajput S C Garg

 

 

 

Power flow control with PWM controlled capacitor for series compensation of a longitudinal a.c. power transmission system

323

        G Panda

 

 

 

A novel double distilled water plant : Fully automatic without automation

330

        R Prasad

 

 

 

Corrosion monitoring in Nigerian petroleum industry: A case study of Kaduna petroleum refinery

 

 

335

        J O Odigure, A S Abdulkareem, O D Adeniyi & O Abdullahi

 

 

 

Horizontal solute dispersion in unsteady flow through homogeneous finite aquifer

339

        Naveen Kumar & Mrituanjay Kumar

 

 

 

Effect of radial magnetic field on the stability of Dean flow

344

        M A Ali

 

 

 

Materials Science

 

Wear behaviour of titanium alloy GTM-900 under dry sliding

351

        J P Pathak, S Mohan & V Singh

 

 

 

Microhardness studies on Bi-In single crystal

359

        Sanjeeta Rani & G K Chadha

 

 

 

Fracture behaviour of brittle matrix and alumina trihydrate particulate composites

365

        A Chennakesava Reddy

 

 

 

 

 

 

Effect of structure on the mechanical and thermal properties of glass fabricreinforced silicon containing epoxy resins

369

        Parveen Khurana, S Aggarwal, A K Narula & Veena Chaudhary

 

 

 

Thermally stimulated discharge conductivity of PVC thin film

375

        S S Yawale, A A Kakade, V R Bhonde, C S Ulhe, D S Dhote, S B Sawarkar
G T Lamdhade & S P Yawale

 

       

 

 

 

Relationship between the breakage and wetting characteristics of lignite

383

        M Yekeler & A Ozkan

 

 

 

Note

 

 

 

X-ray diffraction study on sulphur for rubber vulcanization

390

        K L Barui & B Bhattacharya

 

 

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, October 2002, pp. 311-314

 

 

Symmetry in planetary gear trains

A C Rao & Y V D Rao

 

Along with the generation of gear trains it will be useful for the designer to know other structural characteristics.  Symmetry is one such characteristic. Structural symmetry will make the balancing easy. This will also reduce the generation effort. In this paper, an attempt is made to compare all the planetary gear trains with up to four gear pairs (or six elements) based on symmetry.

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, October 2002, pp. 315-322

 

Instrumentation for a retarding potential analyzer for measurement of electron parameters

S S Rajput & S C Garg

 

Various design considerations and their implementation in an instrument, designed for measurement of electron parameters on-board Indian satellites SROSS-C2, along its orbital path are presented. The proposed instrument measures the electron density in the range 5´102 –5´106 cm–3, electron temperatures from 500 K to 4000 K, and photoelectron flux of energy 3-30 eV of the order 108 cm s–1 with full-scale instrument sensitivity 0.2%. Experimental results obtained during testing and flight demonstrate the instrument performance.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, October 2002, pp. 323-329

 

 

Power flow control with PWM controlled capacitor for series compensation of a longitudinal ac power transmission system

G Panda

 

This paper presents a variable reactance type series compensator with pulse-width modulation (PWM) capability. The scheme consists of force-commutated switches (GTOs), in a bi-directional configuration, to bypass or insert a series capacitor into the longitudinal ac power transmission system. The switches are turned on at zero voltage and turned off at a variable time in the ac cycle, which provides a means for continuously controlling the equivalent reactance of the series compensator. No low order harmonics are generated since the force-commutated switches can operate at frequencies higher than that of the ac mains. The basic operating principles and performance characteristics of the PWM controlled series capacitor are described here. The physical background of the basic difference between PWM controlled series capacitor (CSC) and a static synchronous series compensator (SSSC) in terms of power flow control are also presented. The developed theory has been simulated for a typical longitudinal transmission system of an urban metropolis of this country using digital computer.

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, October 2002, pp. 330-334

 

 

A novel double distilled water plant : Fully automatic without automation

R Prasad

 

A novel double distilled water plant has been designed and fabricated with the main objectives to overcome the drawbacks of existing conventional plants and to save energy. The detailed schematic drawing of the plant is given; its operating procedure is also discussed. Its working is based on a non-conventional method of vaporizing water. All the aspects of the experimental observations and results are discussed thoroughly. The rate of distillation is observed to increase with rise in the cumulative volume of the distillate. The proposed plant has got versatile applications. Single distilled water can be produced from the same unit. Good quality pyrogen free distilled water is obtained.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, October 2002, pp. 335-338

 

 

Corrosion monitoring in Nigerian petroleum industry : A case study of
Kaduna petroleum refinery

J O Odigure, A S Abdulkareem, O D Adeniyi & O Abdullahi

 

Corrosion monitoring in a petroleum refinery was carried out using coupon test method. Five different locations were selected along the pipeline of the cooling water section of the refinery. Analysis revealed that there was corrosion taking place at different rates within the refinery. The lowest rate recorded was 14 mg dm-2 day-1 and the highest rate was 42 mg dm-2 day-1. It is recommended that the chemical dosage of corrosion inhibitors be improved and that a constant monitoring program be adopted.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, October 2002, pp. 339-343

 

Horizontal solute dispersion in unsteady flow through homogeneous finite aquifer

Naveen Kumar & Mrituanjay Kumar

 

The pattern of solute transport up-gradient from a point source is studied for the condition of unsteady horizontal groundwater flow in homogeneous aquifer of finite dimensions which occurs in tropical regions. The seasonal sinusoidal variation of groundwater velocity in such regions is represented by a time-dependent expression. Supposing the aquifer is initially solute free, the governing advective-dispersive equation along with the input boundary condition is solved by using the finite Hankel transform. For this the Cartesian frame of reference is transformed into cylindrical one. The analytical solutions are illustrated for a set of input parameters.

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, October 2002, pp. 344-350

 

 

Effect of a radial magnetic field on the stability of Dean flow

M A Ali

 

The effect of a radial magnetic field on the stability of an electrically conducting incompressible fluid between two concentric non-conducting cylinders is considered. The cylinders are at rest and the motion of the fluid is due to a pressure gradient acting in the transverse direction. For arbitrary gap widths between the cylinders, the equations governing the marginal stability state of the flow are derived and solved numerically. The calculated critical parameters characterizing the onset of instability of the flow indicate that the presence of a radial magnetic flow contributes to a more stable flow. It also causes the Taylor cells to contract in the axial direction of the cylinders. These effects depend on the gap width between the cylinders and are more pronounced in the presence of a strong magnetic field.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, October 2002, pp. 351-358

 

 

Wear behaviour of titanium alloy GTM-900 under dry sliding

 

 

 

J P Pathak, S Mohan & V Singh

 

Dry sliding wear behaviour of titanium alloy GTM-900 was investigated using a pin-on-disc wear testing machine. The alloy was solution treated in the a+b phase fields separately and cooled in air to produce duplex microstructure of primary a and transformed b and fully transformed b in the respective heat treated conditions. The sliding wear rate of the alloy in both of above heat treated conditions was observed to increase with the applied load. However, at a constant load, the rate of wear decreased with an increase in the sliding speed, to a minimum and then increasing trend was observed. Examination of wear debris by stereomicroscope and SEM and analysis of the worn surface by SEM revealed formation and smearing of oxides as well as distortion and removal of the metallic material from the mating surface. Microploughing on the sliding surface of the alloy, and dislodging of the material were also quite evident. The rate of wear was found to be higher in the b-treated than that in the a+b treated condition.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, October 2002, pp. 359-364

 

Microhardness studies on Bi-In single crystal

Sanjeeta Rania & G K Chadhab

 

Microhardness measurements (Vicker’s hardness number) and x-ray studies have been performed on surface in trigonal plane (111), on single crystal specimens of pure Bi and Bi doped with 4 at.% of In at room temperature. Vicker’s hardness number of Bi-In system is less compared to pure Bi. This result provides a means to make Bi, otherwise a brittle metal, ductile by adding a small quantity of In, which will add to its metallurgical and industrial applications. Further, the Vicker’s hardness number is found to be constant along the surface of Bi-In system, implying presence of a uniform phase in it. This suggests that In makes complete solid solution with Bi. The size of atomic radius of In seems to favour substitutional solid solution, where the dopant atoms occupy the sites of the parent atoms and effectively alter the periodicity of Bloch potential and modify the band structure of Bi. Presence of any other phase is not revealed in x-ray diffraction pattern of the Bi-In system and this confirms that the lattice of the doped system is essentially that of bismuth. Cohen’s analytical method of least squares refinement for cubic crystals is modified for a hexagonal lattice and employed to calculate the lattice parameters of Bi and Bi-In system. An expansion of the unit cell is reported on account of doping. Laue back-reflection photographs show that 3-fold symmetry of pure bismuth lattice is retained after doping.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 9, October 2002, pp. 365-368

 

 

Fracture behaviour of brittle matrix and alumina trihydrate
particulate composites

A Chennakesava Reddy

 

This paper focuses onto the fracture behaviour of brittle matrix and alumina trihydrate particulate composites fabricated by hot pressing at 550-650°C. In the study of fracture mechanism, the particle size of particulate phase and volume fraction are varied. Strength, elastic modulus and density have been measured for composites. When the particles are too close to one another, the composites appear as a continuum and the crack front does not interact with the discrete particles. The fracture energy increases with the surface roughness. Larger particles result in larger cracks.

Indian Journal of Engineering & Materials Sciences

Vol. 9, October 2002, pp. 369-374

 

Effect of structure on the mechanical and thermal properties of
glass fabric reinforced silicon containing epoxy resins

Parveen Khuranaa, S Aggarwala, A K Narulaa*& Veena Choudharyb

 

The effect of the structure of an epoxy resin prepared by curing DGEBA with structurally different aromatic amide-amines containing a silicon group in the backbone on the properties of glass fabric reinforced laminates was studied. The laminates were fabricated by coating epoxy compatible woven glass fabric with DGEBA containing stoichiometric amounts of amide-amines synthesized by reacting 1 mol of bis (4-chlorobenzoyl) dimethylsilane with 2 mol of 4,4'-diaminodiphenyl ether (E)/4,4'-diaminodiphenyl methane (M)/4,4'-diaminodiphenyl sulfone (pS)/3,3'-diaminodiphenyl sulfone (mS)/bis (3-aminophenyl) methyl phosphine oxide (B)/tris (3-amino phenyl) phosphine oxide (T) using dimethyl acetamide as solvent. Interlaminar shear strength (ILSS), flexural strength and flexural modulus of the laminates were in the range of 7-21 MPa, 114-409 MPa and 10-28 GPa respectively. The difference in flexural strength and flexural modulus of the composites can be attributed to the structure of epoxy network. Storage modulus (E') of all composites calculated at 200oC was in the range 5×102-33×102 MPa and glass transition temperature (Tg) was in the range of 139-154oC. The smoke density decreased with an increase in the char yield whereas the presence of phosphorus in the resin resulted in a significant increase in LOI indicating its flame resistant characteristics.

Indian Journal of Engineering & Materials Sciences

Vol. 9, October 2002, pp. 375-382

Thermally stimulated discharge conductivity of PVC thin film

 

S S Yawalea, A A Kakadeb, V R Bhondec, C S Ulhed, D S Dhotee, S B Sawarkarf, G T Lamdhadeg & S P Yawaleh

 

The conductivity and thermally stimulated discharge currents (TSDC) in polyvinyl chloride (PVC) are studied in virgin and electret thin film samples. The V-I characteristics of the films at different temperatures reveal that there are three distinct regions, namely ohmic, square law and power regions. In the square law region, space charge limited conduction is observed. The possibility of Poole-Frenkel or Richardson-Schottky mechanism is also studied. The field-lowering coefficient (b) is calculated. The Richardson-Schottky mechanism is observed. From –log s vs. 1/T plot, the activation energy is estimated. The electrical conductivity is found to increase with decreasing thickness. TSDC and conductivity are measured in the film of electrets in 313-333 K. Single relaxation peak is observed in the discharge current vs. temperature plot which is due to rotation of dipolar group at peak temperature. Initial rise method is adopted to calculate the activation energy. Similarly the activation energy is evaluated from –log s vs 1/T plot of electret samples. The structural investigations are made using the FTIR spectra. The spectra of virgin and electret samples are obtained in 400-4000 cm–1 wave number ranges. Significant change in the structure is observed due to injection charge carriers. The deformation of structure is also observed.

Indian Journal of Engineering & Materials Sciences

Vol. 9, October 2002, pp. 383-389

Relationship between the breakage and wetting characteristics of lignite

 

M Yekeler* & A Ozkan

 

This paper reports the findings of an investigation of the breakage values of lignite to relate the wettability properties. The breakage values, obtained from grinding, are the specific rates of breakage (Si) and the g of value the primary breakage function (Bi,j), and the wettability parameter, which is also easily obtained from contact angle measurements and flotation tests, is the critical surface tension of wetting value of solid (gc).  The grindings were carried out as dry, wet and wet with kerosene aided tests in a laboratory size porcelain ball mill. The products (-212 µm) of the feed sizes of -600+425, -425+300 and -300+212 µm of lignite ground in the mill have been tested to obtain the gc values by contact angle goniometer and our new designed micro-flotation column cell. It is proposed that a relationship exists between the Si and gc value of the lignite sample studied, i.e., higher the Si value from the breakage process, lower the gc value in wetting processes, indicating less wettability in the physical-chemistry based separation methods. There is also another relationship found between the g value of Bi,j (the fineness factor) and the gc value, where g value increases with increasing gc value, except in the kerosene aided grindings. This means, coarser particles produced by grinding will behave more hydrophilic (i.e., water wets the solid completely) in the wetting operations.

Indian Journal of Engineering & Materials Sciences

Vol. 9, October 2002, pp. 390-392

 

X-ray diffraction study on sulphur for rubber vulcanization

K L Barui & B Bhattacharya

 

Identification of allotropic forms of sulphur present in commercial sulphur to be used for rubber vulcanization and the estimation of the percent content of each form present are essentially required for desirable performance characteristics of good quality rubber products. For these purposes x-ray diffraction technique has been chosen as the other conventional methods are incapable of distinguishing different forms of sulphur, viz., normal a-type (orthorhombic) and insoluble w-type (white sulphur or supersublimation sulphur). The w-type (at least 90% by weight) is most suitable, as it remains insoluble in rubber even at very high temperature. In this investigation pure a-type and w-type as well as a sample of commercial type of sulphur have been thoroughly analyzed. This commercial sulphur is found to contain only 60% of insoluble sulphur, which does not at all fulfil the specific requirement. This analysis is very much helpful for quality improvement of rubber products.