Indian Journal of Engineering & Materials Sciences


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VOLUME 12

CODEN : IEMSEW

NUMBER 4

AUGUST 2005

ISSN : 0971-4588

 

 

 

CONTENTS

 

Engineering

 

Design and implementation of PLC cum micro-controller based electrically synchronized lift

 

269

        S N Sivanandam, S Sumathi & S N Deepa

 

        [IPC Code: Int. Cl.7 H02P 6/00]

 

 

 

High input impedance voltage-mode lowpass, bandpass, highpass and notch filter using current feedback amplifiers

 

278

        N A Shah & M A Malik

 

        [IPC Code: Int. Cl.7 H03F 3/00, H03H 3/00]

 

 

 

A numerical study of pre-diffuser optimization of an aero gas turbine combustion chamber

 

281

        G Ananda Reddy & V Ganesan

 

        [IPC Code: Int. Cl.7 F23M]

 

 

 

Flexural response of reinforced-concrete beams based on multidimensional data analysis

 

292

        Fatih Altun, Erkan Beşdok, Tefaruk Haktanir & H Mustafa Palancioğlu

 

        [IPC Code: Int. Cl.7 E04C 5/00]

 

 

 

Materials Science

 

 

Materials by design — Prospects and challenges

299

        S Ahmad

 

        [IPC Code: Int. Cl.7 H01L]

 

 

 

Structural and dielectric properties of MgO doped 0.8PMN-0.2PT solid solution

317

        Yogesh Sharma, Anjan Sil & K L Yadav

 

        [IPC Code: Int. Cl.7 C04B 35/03]

 

 

 

Blue-green emission from organic light emitting diodes based on aluminum complex

321

        Aparna Misra, Pankaj Kumar, Lokendra Kumar, Nikhil Ganesh, Mohit Gupta,
S K Dhawan, M N Kamalasanan & Subhas Chandra

 

        [IPC Code: Int. Cl.7 G02B 6/00, H01L 29/861]

 

 

 

Sintering of cubic boron nitride under high pressures and temperatures in the presence of boron carbide as the binding material

 

325

        S K Singhal & B P Singh

 

        [IPC Code: Int. Cl.7 C01B 35/08, C01B 31/36]

 

Effect of contact geometry on fretting fatigue life of aluminium alloy 2024-T3

331

        G H Farrahi, G H Majzoobi & H Chinekesh

 

        [IPC Code: Int. Cl.7 C21C 21/00, C22F]

 

 

 

Effect of carboxylic acids on the morphology, physical characteristics and hydration of a-hemihydrate plaster

 

337

        N B Singh, C Vellmer & B Middendorf

 

        [IPC Code: Int. Cl.7 C04B 11/00]

 

 

 

Development of low permittivity material using fly ash

345

        Kamal Singh , Tanveer Quazi , Shail Upadhyay & Pramod Sakharkar

 

        [IPC Code: Int. Cl.7 G01 27/26]

 

 

 

Evaluation of fly ash filled chloroprene elastomer composites

351

        S H Bidkar, A G Patil, U R Kapadi & D G Hundiwale

 

        [IPC Code: Int. Cl.7 C22C 47/00]

 

 

 

Distribution of pulse type uniform input in aquifers in tropical regions

356

        Naveen Kumar, Vijay Kumar Singh & R R Yadav

 

        [IPC Code: Int. Cl.7 F15B]

 

______________

 

IPC: International Patent Classification

 

Int. Cl.7: International Classification 7th edition, 1999

 

 

 

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2005, pp. 269-277

 

 

Design and implementation of PLC cum micro-controller based electrically synchronized lift

S N Sivanandam, S Sumathi & S N Deepa

 

Automobile industry is developing most extravagantly. The maintenance of the automobiles plays an important role, which is achieved by latest service station equipments. Electro-mechanical two-post lift is used to lift the vehicle to top or bottom and performs the required service operations under chassis. As in the present design and fabrication of the two-post lift, sprockets and chain mechanism are present for the transmission of the drive, but this results in slight non-linearity in the arm arrangements. This non-linearity in worst case may result in destruction of the automobile placed on the lift. The main aim of this paper is to avoid this non-linearity hence synchronization control of the arm movements is proposed for automating the lift, by removing the sprocket and chain mechanisms. The synchronization is implemented using two types of controllers, which includes micro-controller and the programmable logic controller. An inductive proximity sensor is selected to sense the rotation of the motors and produce pulses, which is used to control the movement of arm arrangements. The micro-controller programming is implemented using the software AVR Studio 3.5. The programmable logic controller programming is performed using the software STEP-7 Micro/Win 32.

IPC Code: H02P6/00

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2005, pp. 278-280

 

High input impedance voltage-mode lowpass, bandpass, highpass and
notch filter using current feedback amplifiers

 

N A Shah & M A Malik

 

The paper presents a new voltage-mode (VM) high input impedance filter having a single input and four low impedance outputs. The proposed circuit employs four current feedback amplifiers (CFAs) and six passive elements, four of them are grounded and enjoys the following advantages: simultaneous realisation of lowpass (LP), bandpass (BP), highpass (HP) and notch filtering functions explicitly, cascadability, independent control of resonance frequency (w0) and bandwidth (w0/Q), orthogonal control of resonance frequency (w0) and quality factor (Q), no requirements for component matching conditions, use of two grounded capacitors which are ideal for IC implementation and low passive sensitivity figures. Experimental and PSPICE simulation results are given to verify the theoretical calculations.

IPC Code: H03F3/00, H03H3/00

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2005, pp. 281-291

 

 

A numerical study of pre-diffuser optimization of an aero gas

turbine combustion chamber

 

G Ananda Reddy & V Ganesan

 

This paper describes the attempts made in the optimization of pre-diffuser geometry of an aero gas turbine combustion chamber for obtaining minimum total pressure losses and for good static pressure recovery. Optimization of pre-diffuser has been attempted by changing the geometric parameters like length, divergence angle and wall contour. A 20° sector has been considered for the present study because of the periodicity with respect to the air blast atomizer. The geometry is modeled using GAMBIT and CATIA software. Meshing is done by GAMBIT. The governing equations are solved using the SIMPLE algorithm with iterative multigrid acceleration. Turbulence effects are simulated using the (RNG) k-e model. Flow field characteristics have been analyzed. Optimization is attempted from the point of view of achieving minimum pressure loss. From the present study it is concluded that a 6° straight walled pre-diffuser with area ratio of 1.6594 and a dump gap ratio (D/H) of 1.08 is found to be most optimum, considering the flow development and minimum total pressure loss.

IPC Code: F23M

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2005, pp. 292-298

 

 

Flexural response of reinforced-concrete beams based on multidimensional data analysis

Fatih Altun, Erkan Beşdok, Tefaruk Haktanir & H Mustafa Palancioğlu

 

Experimental investigation of behaviour and ultimate failure mechanisms of reinforced concrete (RC) beams help to better understand their in-situ reactions in RC structures and enable more realistic designs to be made. In this study, a total of nine RC beams with varying dimensions have been produced and subjected to flexural loading. The mid-section displacements and the loads have been measured. In order to investigate and model the load-displacement behaviour of RC beams of different configurations in detail, a multidimensional data analysis technique has been used. The triangular-base multidimensional data analysis (TBI) procedure applied herein is generally used for digital terrain modelling especially in geodesy and photogrammetric engineering and computer-aided modelling applications. Comparison of the experimentally determined relationships with those given by the developed TBI model has revealed close agreements. With the help of this TBI model, the approximate behaviour of an RC beam of certain dimensions for which the strength of concrete and the amount of reinforcement are given can be determined very closely. The classical finite element method has been used in the prediction of behaviours of RC beams in conjunction with the developed TBI model.

IPC Code: E04C5/00

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2005, pp. 299-316

 

Materials by design—Prospects and challenges

S Ahmad

 

The present form of material science and technology in practice is an outcome of ‘discovery based approach’, in which various features of the materials are investigated in detail and the acquired knowledge is put to use in looking for their possible applications in different fields. In this endeavor, a variety of processes and products are developed using available scientific knowledge and technological methods based on mostly heuristic approach. With the recent development of nanoparticle size materials and study of their characteristic properties, it is foreseeable that in coming 10 to 20 years, it will be feasible to use a systematic approach of ‘problem based search for solution’ in material science and technology. This implies that it will be quite possible to synthesize a material with tailored properties required for a given situation under consideration. A systematic design methodology is under active development in this context where the physical, chemical and biological behaviour of different types of nanoparticle size material building blocks will be put to use to have the right kind of the synthetic material that will fulfill the needs. Theoretical models, developed in this context, will not only help in deciding the final composition details in terms of different building blocks but would also provide help to work out reliable and reproducible routes to manufacture the designed materials in an economical way. This situation will arise only after having complete understanding of the relationship between nanoparticle size and composition to their physical, chemical and biological behaviours. Next comes the development of reliable models to study the interactions with each other among such building blocks based on ‘cause and effect’ principles like thermodynamics and kinetics. Laboratory scale experimental validations would be established through a variety of model materials to generate library of unit processes related to material synthesis. These models could also be used in developing fast screening procedures to find out the most probable routes of synthesis without going through the time consuming and costly experimental route alone. While taking the advantages of chemical synthesis, already in progress at a fast pace, it will be additionally beneficial to develop self-assembled monolayer (SAM) material growth technology combined with molecular recognition technique to synthesize newer materials and components. Bioinspired material synthesis techniques, based on SAM and molecular recognition, which are very much prevalent in nature, would thus add another dimension to design materials for specific applications. Highly sophisticated measurement and characterization tools would be required to probe extremely small material particles and their collective behaviour while studying the correlation between nanostructure and their characteristic features. This approach of ‘materials by design’ is certainly going to revolutionize the materials technology in a big way. A clear case of paradigm shift is apparent in relation to the way material science and technology problems are solved by the scientists and engineers in near future. Global cooperation and collaborations among the workforces, deployed in different countries in such development projects, besides the development of matching pattern of undergraduate and graduate level educational programs will be critically important for commensurate speed of the overall developments. ‘Materials by design’ is a global problem solving approach and therefore all must put in their best and comprehensive efforts. Sooner we prepare ourselves and enter into the mainstream, better it will be to reap the fruits of such global efforts. The importance of various R&D initiatives to be taken up in this context is highlighted in this paper. Very brief description of our own R&D activities in various National Laboratories and Academic Institutions in the area of nanotechnology is also included here for the benefit of the readers. Efforts have been made in this paper to present a simplified picture of the challenging problems to be sorted out in connection with the preparation for ‘materials by design’ methodology development.

IPC Code: H01L

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2005, pp. 317-320

 

Structural and dielectric properties of MgO doped 0.8PMN-0.2PT solid solution

 

Yogesh Sharma, Anjan Sil & K L Yadav

 

In the present work, perovskite PMN and 0.8 PMN-0.2 PT solid solution were prepared by columbite processing technique. The effect of minor addition of excess (1 wt.%) MgO on the microstructure and dielectric constant of the samples in 0.8PMN-0.2PT sintered at 900°C and 1000°C for 4 h in PbO-rich atmosphere was investigated. The addition has resulted higher dielectric constant with an increase in transition temperature. Also average grain size has increased. Due to the excess MgO addition, the nature of phase transition has also been changed from diffuse to near normal behaviour.

IPC Code: C04B35/03

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2005, pp. 321-324

 

Blue-green emission from organic light emitting diodes

based on aluminum complex

 

Aparna Misra, Pankaj Kumar, Lokendra Kumar, Nikhil Ganesh, Mohit Gupta,
S K Dhawan, M N Kamalasanan & Subhas Chandra

 

Bluish-green emission from double layer organic light emitting diode (OLED), based on an aluminium complex, bis-(2-methyl 8-hydroxyquinoline) aluminium hydroxide (Almq2OH), as an emissive material and N,N˘-bis(3-methylphenyl)-N,N˘-bis(phenyl)benzidine (TPD), as hole transport material with an electro-luminescence maximum at 506 nm, has been reported. The good thermal stability, good performance for the OLED applications, and a noticeable blue shift in the electroluminescence, in comparison to Alq3, make this Al complex a good contender for OLED applications for light emission in the blue-green region. It was also found that the devices based on this material have a slightly higher turn-on voltage than similar Alq3 devices. This can be attributed to the higher energy-gap of the material. The photoluminescence and electroluminescence spectra are reported and a shift of 9 nm in peaks is observed. The current-voltage characteristics of the device have also been studied.

IPC Code: G02B6/00, H01L29/861

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2005, pp. 325-330

 

 

Sintering of cubic boron nitride under high pressures and temperatures in the presence of boron carbide as the binding material

 

S K Singhal & B P Singh

 

Sintering of cubic boron nitride (cBN) was carried out by subjecting fine powders of cBN to high pressures and temperatures (P = 50-60 kb, T = 1200-1500°C ) in the presence of boron carbide as the main binding material together with a small amount of aluminium nitride. The composites were characterized by X-ray diffraction, scanning electron microscopy, FTIR, Raman Spectroscopy and microhardness measurements. Best composites with a maximum microhardness of about 3700 kg/mm2 were obtained at around 50 kb, 1450°C using 75 wt% of cBN in the mixture. No peaks due to hexagonal boron nitride were observed in the XRD patterns.

IPC Code: C01B35/08, C01B31/36

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2005, pp. 331-336

 

Effect of contact geometry on fretting fatigue life of aluminium alloy 2024-T3

G H Farrahi, G H Majzoobi & H Chinekesh

 

The effect of contact geometry on fretting fatigue life was investigated by experiments and numerical simulation. The experiments were conducted for flat and cylindrical pads under the same contact normal force. The post-test examinations including crack growth measurements and fractography were carried out using optical and scanning electron microscopy (SEM). Numerical simulations of pad-specimen assembly with and without crack were performed using a finite element (FE) analysis. The experimental study revealed that the rate of crack growth was higher at the early stages of fretting fatigue for cylindrical pads. This stage corresponds to a higher KII for cylindrical contact model. After this stage, the effects of friction force and KII decrease and the effects of tensile stress and KI become more significant. The experimental results also showed that fatigue life of AA2024 reduced by nearly 75% under fretting fatigue condition. However, the reduction for cylindrical contact geometry was more than that measured for flat contact model. The numerical results indicated that the maximum shear, tensile, and Von-Mises stresses which are thought to be the origin for initiation and growth of crack, occur at the trailing edge of the contact surface for flat and cylindrical pads. SEM examination confirmed that the crack initiated from the points of stress maxima.

IPC Code: C21C21/00, C22F

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2005, pp. 337-344

 

Effect of carboxylic acids on the morphology, physical characteristics and hydration of a-hemihydrate plaster

 

N B Singh, C Vellmer & B Middendorf

 

Hydration of a-hemihydrate in the presence of different concentrations of tartaric, succinic, malic and citric acids was studied. All the acids, except tartaric acid, retard the hydrations. pH measurements have shown that during hydration acids are adsorbed at solid surfaces, leading to the retardation of hydration. E-modulus of elasticity, tensile strengths, total porosity, compressive strength, morphological and temperature changes during hydration were studied. It is found that morphological changes control the strength properties.

IPC Code: C04B11/00

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2005, pp. 345-350

 

Development of low permittivity material using fly ash

 

Kamal Singh, Tanveer Quazi , Shail Upadhyay & Pramod Sakharkar

 

Dielectric behaviour of fly ash, barium titanate and three composites of fly ash and barium titanate have been measured in the temperature range 30-200°C and frequency range 100 Hz –1 MHz. It is observed that dielectric constant of fly ash and composite is low as compared to barium titanate. Moreover, the dielectric constant of fly ash and composites is independent of temperature in the entire range of temperature measurement. It is found that the experimental values of dielectric constant of the composites are in agreement with theoretical value calculated using logarithmic mixing rule given by Linchtenecker for determination of effective dielectric constant of the composite.

IPC Code: G01R27/26

  

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2005, pp. 351-355

 

Evaluation of fly ash filled chloroprene elastomer composites

 

S H Bidkar, A G Patil, U R Kapadi & D G Hundiwale

 

Filled elastomer composites are the popular for many engineering applications. Most commonly used fillers for non-black applications are china clay, talc and calcium carbonate. Fly ash, a waste mineral product of thermal power stations, was studied for the effect on physico-mechanical properties of polychloroprene composites. These composites filled with calcium carbonate, talc, china clay and fly ash were evaluated and technical properties were correlated with the help of chemical crosslinking and morphological study. The results proved that the properties were mainly associated with the high crystalline nature of the elastomer and also it could be concluded that fly ash could be utilized for curbing the environmental pollution with economic advantage.

IPC Code: C22C47/00

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2005, pp. 356-362

 

Distribution of pulse type uniform input in aquifers in tropical regions

Naveen Kumar, Vijay Kumar Singh & R R Yadav

 

The present work presents mathematical models for the distribution of solute concentration of uniform input of pulse type along sinusoidally varying unsteady longitudinal velocity through such inhomogeneous aquifers of finite as well as semi-infinite extents whose main source of replenishment is infiltration during rains. A new time variable is introduced by using an expression in old time variable. Numerical solutions of such models are obtained using finite difference approximations. At initial stage the dispersion problem is considered steady one in homogeneous aquifer. Its solution is considered as initial condition for the respective unsteady problems. To achieve minimum time period of computation, the parameters of the problem are non-dimensionalized in terms of the existing variables in cases of semi-infinite and finite aquifers separately. The effects of inhomogeneity in both cases are shown through illustrations.

IPC Code: F15B