Indian Journal of Engineering & Materials Science

 

 

Total visitors: 803  since 21-02-07

 

VOLUME 14

CODEN : IEMSEW

NUMBER 2

APRIL 2007

ISSN : 0971-4588

 

CONTENTS

 

Engineering

 

 

Thermoelastic analysis of a laminated composite skew plate with a circular cutout subjected to linearly varying temperature across the thickness

 

95

        A V Sudhakar, K Mohana Rao & V Ramachandra Raju

 

        [IPC Code: C08]

 

 

Effect of orientation angle of elliptical hole on residual stresses and expansion of plastic zone in thermoplastic composite plates under in-plane loading

 

103

        Mehmet Aktas & Ramazan Karakuzu

 

        [IPC Code: B29]

 

 

Development of potassium-selective ion-sensitive field-effect transistor (ISFET) by depositing ionophoric crown ether membrane on the gate dielectric, and its application to the determination of K+-ion concentrations in blood serum

 

 

112

        V K Khanna, S Ahmad, Y K Jain, M Jayalakshmi, S Vanaja, S S Madhavendra,
s v Manorama & M Lakshmi Kantam

 

        [IPC Code: C12, C25, G01, H01L21/535]

 

 

Practical aspects which affect an electrical measurement

119

        K B Ravat & S K Mahajan

 

        [IPC Code: H03]

 

 

Fabrication of narrow bandpass filters for wavelength division multiplexing applications — A feasibility study

 

125

        A Basu, K M K Srivatsa, T K Chakraborty & T K Bhattacharya

 

        [IPC Code: G02B1/10, G02B2/28]

 

 

Seismic behaviour of cylindrical elevated tanks with a frame supporting system on various subsoil

 

133

        Ramazan Livaoglu & Adem Dogangun

 

        [IPC Code: E03B11/12]

 

 

Materials Science

 

 

Drying shrinkage of cementitious composites with mineral admixtures

146

        R Malathy & K Subramanian

 

        [IPC Code: C04B]

 

Investigation of the low temperature performances of polymer and fiber modified asphalt mixtures

 

151

        Yuksel Tasdemir & Emine Agar

 

        [IPC Code: C10C]

 

Effect of cement and EPS beads ratios on compressive strength and density of lightweight concrete

 

158

        Abdulkadir Kan & Ramazan Demirboğa

 

        [IPC Code: C04B26/02]

 

 

Strain induced non-linear conduction in epitaxial La0.7A0.3MnO3 manganite thin films

163

        P S Vachhani, P S Solanki, J H Markna, R N Parmar, J A Bhalodia &
D G Kuberkar

 

        [IPC Code: H01F10/00]

 

 

Dielectric relaxation studies of binary mixtures of N-methylformamide and benzonitrile in benzene solution using microwave absorption data

 

167

        Rajesh Kumar, Nagesh Thakur, D R Sharma, V S Rangra & N S Negi

 

        [IPC Code: G01R27/26]

 

_______________

 

IPC: International Patent Classification

 

Int. Cl.8: International Classification 8th edition, 2006

 

 

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 14, April 2007, pp. 95-102

 

Thermoelastic analysis of a laminated composite skew plate with a circular cutout subjected to linearly varying temperature across the thickness

A V Sudhakar, K Mohana Rao & V Ramachandra Raju

 

The behaviour of a laminated composite skew plate with hole subjected to temperature as well as combined temperature and transverse pressure loading has been investigated. A finite element method which works on the basis of three-dimensional theory of elasticity is employed to evaluate the transverse deflection, in-plane stresses and interlaminar stresses. The results obtained by varying the skew angle and the hole diameter are discussed. It has been observed that the magnitude of the stresses and deflection in case of combined loading is more when compared with the respective values in case of pure thermal loading. The magnitudes of the transverse deflection and in-plane stresses for combined loading are observed to be less at higher skew angles, because the distance between opposite sides of the plate decreases with increase in skew angle causing for increase in the stiffness of the plate. The solutions of skew structures considered in the present analysis will be useful for the construction of safe and efficient structures like skew bridges and swept wings of aircraft structures.

IPC Code: C08

 

 

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 14, April 2007, pp. 103-111

 

 

Effect of orientation angle of elliptical hole on residual stresses and expansion of plastic zone in thermoplastic composite plates under in-plane loading

Mehmet Aktas & Ramazan Karakuzu

 

In this study, residual stress variations and expansion of plastic zone of woven steel fiber reinforced laminated thermoplastic composite plates with central elliptical hole which is subjected to in-plane loading are investigated for different loads. Numerical simulation is performed using a commercial packet programme ANSYS. To investigate the effects of orientation angle of elliptical hole in the composite laminated plate under various in-plane loads, elliptical hole is rotated from 0° to 90° by 15° increments counterclockwise. The in-plane loads are chosen as 5.5 MPa, 6.0 MPa and 6.5 MPa. Laminated plates are composed of [0/±30/±45/90]2 fiber orientation in symmetric and antisymmetric manner.

IPC Code:  B29

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 14, April 2007, pp. 112-118

 

 

Development of potassium-selective ion-sensitive field-effect transistor (ISFET) by depositing ionophoric crown ether membrane on the gate dielectric, and its application to the determination of K+-ion concentrations in blood serum

 

V K Khanna, S Ahmad, Y K Jain, M Jayalakshmi, S Vanaja, S S Madhavendra,
s v Manorama & M Lakshmi Kantam

 

This paper reports the fabrication and characterization of potassium ISFET (ion-sensitive field-effect transistor) by deposition of a crown ether layer on the gate. This ISFET is referred to as potassium MEMFET (membrane field-effect transistor) or potassium-selective MEMFET device. Calibration of ISFET in standard KCl solutions has shown that the sensitivity of crown ether-ISFET towards potassium (2.3 mV/mg/L) was approximately double that of the nitride-gate ISFET (1 mV/mg/L) in the 100-400 mg/L range. The mechanism of ISFET potassium sensitivity enhancement by the ionophoric crown ether layer on the gate has been explained. Use of the device for potassium concentration measurements in human blood serum has been demonstrated. The distribution of potassium ion concentrations (151-210 mg/L) in a series of human blood serum samples has been determined from the reference value obtained by atomic absorption spectroscopy and the ISFET sensitivity measured with KCl solutions. These diluted samples showed a constant pH ~ 7.0-7.1, confirming the maintenance of pH within close tolerance by the human body; therefore any errors due to pH variation amongst the samples were eliminated. Sensitivity of the ISFET with/without crown ether coating on the gate towards sodium ions (0.34 mV/mg/L) has been found to be comparatively less than that of the crown ether ISFET for potassium, showing that sodium ions in blood serum do not interfere with the measurements.

IPC Code: C12, C25, G01, H01L21/335

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 14, April 2007, pp. 119-124

 

 

Practical aspects which affect an electrical measurement

 

K B Ravat & S K Mahajan

 

This paper focuses on some of the practical considerations for electrical measurement. Though these are not measurement techniques but have a very significant effect on precision measurement. Some of these are leakage currents, thermal effects, contact resistance, transients, grounding, shielding, earthing, guarding and drift. The precision measurement depends on control of all these important but sometimes subtle factors.

IPC Code: H03

 

Indian Journal of Engineering & Materials Sciences

Vol. 14, April 2007, pp. 125-132

 

 

Fabrication of narrow bandpass filters for wavelength division multiplexing applications – A feasibility study

A Basu, K M K Srivatsa, T K Chakraborty & T K Bhattacharya

 

Thin film multilayer narrow bandpass interference filters are widely used in wavelength division multiplexing (WDM) applications in fibre optic communication systems. These filters must have sharp cut-on and cut-off on either side of the passband and practically zero transmittance outside the passband, over the wavelength range of the application. In an effort to demonstrate the feasibility of fabrication of WDM filters, the simpler designs for these filters (involving deposition of multilayers with 30-35 layers) have been examined and their fabrication has been demonstrated using a vacuum coating system with limited capabilities, at several wavelengths in the range of interest. This experience has shown that with the use of modern vacuum coating plants equipped with sophisticated coating and monitoring facilities, the fabrication of WDM filters with more complex designs and meeting commercial specifications [at least coarse WDM (CWDM) filters with somewhat less stringent specifications] can be a feasible proposition.

IPC Code: G02B 1/10, G02B 5/28

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 14, April 2007, pp. 133-145

 

Seismic behaviour of cylindrical elevated tanks with a frame supporting
system on various subsoil

 

Ramazan Livaoglu & Adem Dogangun

 

The seismic responses of an elevated tank with a frame supporting system on various subsoils are investigated. The finite element method is used for the modelling of the elevated tank and subsoil system. Fixed-base and elastic media assumptions are made for subsoil. The tank fluid has been modelled as lumped masses such as impulsive and convective masses proposed by Housner. An added mass approach is used for fluid-structure interaction by representing both the impulsive mass and the convective mass. For estimating the seismic response of elevated tanks, response spectrum analysis with mode superposition is used. The results obtained from modelling the elevated tanks on a fixed base and on an elastic medium are compared. It has been observed that the seismic response of the elevated tank is altered significantly depending on the properties of the subsoil. The soil-structure interaction especially affects the impulsive modes and lateral displacement of elevated tanks rather than the torsional modes. It is proposed that the coupling effect for perpendicular directions in the axisymmetrical plan geometry should be considered in the seismic design of the elevated tanks.

IPC Code: E03B11/12

 

Indian Journal of Engineering & Materials Sciences

Vol. 14, April 2007, pp. 146-150

 

 

 

Drying shrinkage of cementitious composites with mineral admixtures

R Malathy &  K Subramanian

 

This paper emphasises on the influence of mineral admixtures (MA) like silica fume, metakaoline and fly ash on the drying shrinkage of cement mortars incorporated with MA as cement replacement material. MA has been varied at different percentages from 0 to 15% at the constant increment of 5%. The water-binder (cement + MA) ratio and binder-sand ratios are 0.5 and 1:3 respectively.  The short-term and long-term ultimate drying shrinkage of mortar has been studied. The effect of size of sand particles has been studied with different sizes of particles fractions. The highest drying shrinkage has been observed in mortars with higher silica fume contents at the age of 28 days. At the early ages, this has been due to the high pozzolanic reaction of silica fume, as a result of pore-size refinement mechanism of silica fume. However, the effect of silica fume has not been significant on the long-term drying shrinkage. The effect of grain size demonstrates that the ultimate drying shrinkage decreases as the size of sand particles increases.

IPC Code: C04B

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 14, April 2007, pp. 151-157

 

 

Investigation of the low temperature performances of polymer and fiber modified asphalt mixtures

Yuksel Tasdemir & Emine Agar

 

In this study, effects of polymer and fiber modification on low temperature properties of bituminous mixtures were studied. One aggregate, one asphalt binder type, three additives (polymer, synthetic fiber and loose cellulose fiber) and three 85°C oven aging levels (0, 5 and 25 days) were considered. The thermal stress restrained specimen test (TSRST) was used to evaluate the low temperature cracking resistance and aging performance of modified asphalt concrete specimens. The analysis of covariance was performed using a general linear model (GLM) procedure on the TSRST results by using statistical analysis system (SAS) software. Aging levels and type of additive were determined as most important factors that affect fracture temperature and fracture strength. Fracture temperature becomes warmer with the increase in the degree of aging. It was observed that fracture temperature and fracture strength change according to additive type used.

IPC Code: C10C

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 14, April 2007, pp. 158-162

 

Effect of cement and EPS beads ratios on compressive strength and
density of lightweight concrete

Abdulkadir Kan & Ramazan Demirboğa

 

The compressive strengths and slump values of concretes made up of mixtures of expanded polystyrene (EPS) beads and cement were investigated. To determine the effect of Portland cement (PC)/EPS ratio, on the compressive strength of EPS concrete, 1/0 (control sample), 1:4, 1:2, 3:4 and 1:1 mix proportion by volume were used. EPS beads content for the mixtures were kept constant at 0.05 m3. The analysis of the test results leads to the conclusion that with the increase of cement to EPS beads ratio in the mixes, both density and compressive strength of concretes increased up to 4 and 350 times respectively, when compared to the control sample. Hardened concrete densities and compressive strength varied from 464 to 1940 kg/m3, and 0.11 to 38.50 MPa, respectively. Slump values of the mixes were changed from 8 to 43 mm.

IPC Code: C04B26/02

 

Indian Journal of Engineering & Materials Sciences

Vol. 14, April 2007, pp. 163-166

 

Strain induced non-linear conduction in epitaxial La0.7A0.3MnO3
manganite thin films

 

P S Vachhani, P S Solanki, J H Markna, R N Parmar, J A Bhalodia & D G Kuberkar

 

In this paper, the current-voltage (I-V) properties of La0.7A0.3MnO3 (A = Ca, Sr, Ba) manganite thin films grown on single crystalline LAO (100) substrate using chemical solution deposition (CSD) technique have been reported. Epitaxial nature of all the films has been confirmed from XRD measurements. The I-V measurements carried out on La0.7Ba0.3MnO3 (LBMO) films show an unusual non-linear transport behaviour contrary to that observed for La0.7Ca0.3MnO3 (LCMO) and La0.7Sr0.3MnO3 (LSMO) films. This non-linearity has been explained in terms of non-uniform strain distribution resulting due to mismatch in the lattice parameters of LBMO film and substrate. The conductance data for all the films have been fitted using Simmon’s model and the possible mechanism of charge conduction in the films has been discussed.

IPC Code: H01F10/00

Indian Journal of Engineering & Materials Sciences

Vol. 14, April 2007, pp. 167-172

 

 

Dielectric relaxation studies of binary mixtures of N-methylformamide and benzonitrile in benzene solution using microwave absorption data

 

Rajesh Kumar, Nagesh Thakur, D R Sharma, V S Rangra & N S Negi

 

Using standard standing wave microwave techniques and following the single frequency (9.885 GHz) concentration variational method, the dielectric relaxation time (τ) and dipole moment (μ) of binary mixtures of different molar concentrations of N-methylformamide (NMF) in the binary mixtures of N-methylformamide (NMF) and benzonitrile (C6H5CN) in benzene solutions have been calculated at different temperatures (25, 30, 35 and 40°C). The energy parameters (ΔHε, ΔFε, ΔSε) for the dielectric relaxation process of binary mixtures containing 50 mol% of NMF have been calculated at different temperatures and comparison has been made with the corresponding energy parameters (ΔHη, ΔFη, ΔSη) for the viscous flow process. Based on these studies, it is inferred that dielectric relaxation process can be treated as a rate process just like the viscous flow process. Solute-solvent molecular associations have been proposed.

IPC Code: G01R27/26