
Archive issue  vol.8 No.2
No. 
Author(s)  Title 
Pages 
1. 
S.Das  A pair of equal collinear interfacial cracks between bonded dissimilar fixed isotropic layers 
167175 
2. 
S.Debsarma and K.P.Das  Fourth order nonlinear evolution equation for capillary gravity waves in deep water in the presence of a thin thermocline including the effect of wind 
177193 
3. 
P.Ganesan and P.Loganathan  Effects of heat and mass transfer on a moving vertical cylinder with chemically reactive species diffusion 
195205 
4. 
Z.Garncarek, W.Grzeszczyk and J.Szymczak  Quantitative analysis of nonhomogeneity of thermal fields from thermal images of building plasters 
207217 
5. 
A.S.Gupta, A.Pal, B.Pal and H.S.Takhar  Hall effects on MHD flow and heat transfer over a stretching surface 
219232 
6. 
A.K.Haghi  The diffusion of heat and moisture through textiles 
233243 
7. 
S.Haldar, M.C.Manna and A.H.Sheikh  Static analysis of isotropic thick/thin skew plates by finite element method 
245254 
8. 
M.Kireitseu  Rheological behavior and fatigue of aluminum oxidebased composite structures on soft substrates 
255270 
9. 
R.M.Patel and G.M.Deheri  Magnetic fluid based squeeze film behaviour between rotating porous circular plates with a concentric circular pocket and surface roughness effects 
271277 
10. 
G.Quaglia  Semiactive magnetorheological suspension performance 
279298 
11. 
J.N.Sharma, P.K.Sharma and S.K.Gupta  On the wave propagation in generalised thermoelastic media 
299316 
12. 
I.Stiharu, R.Bhat and H.Hong  A friction model of microbearings with thin metallic compliant coatings 
317329 
13. 
Brief note Rajesh C. Shah and M.V.Bhat  Magnetic fluid based porous inclined slider bearing with velocity slip 
331336 

1.
A PAIR OF EQUAL COLLINEAR INTERFACIAL CRACKS BETWEEN BONDED DISSIMILAR FIXED ISOTROPIC LAYERS
S. DAS
Department of Mathematics
B.P. Poddar Institute of Management and Technology
Poddar Vihar, 137, V.I.P. Road
Kolkata  700 052, West Bengal, INDIA
email: sananda_das@hotmail.com
The problem of a pair of equal collinear Griffith cracks propagating with constant velocity under antiplane shear stress at the interface of two bonded dissimilar fixed isotropic layers has been considered. The method of Fourier transforms is employed and the problem is reduced to the solution of a singular integral equation, which has finally been solved numerically by using Chebyshev polynomials. The stress intensity factors at the crack tips and the crack opening displacement have been calculated numerically for some particular cases and displayed graphically.

Key words: 
Griffith crack, Fourier transform, integral equation, Hilbert transform, stress intensity factor, crack opening displacement. 
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2.
FOURTH ORDER NONLINEAR EVOLUTION EQUATION FOR CAPILLARY GRAVITY WAVES IN DEEP WATER IN THE PRESENCE OF A THIN THERMOCLINE INCLUDING THE EFFECT OF WIND
S. DEBSARMA and K.P. DAS
Department of Applied Mathematics, University of Calcutta
92, A.P.C. Road, Kolkata  700 009, INDIA
email: kpdas@cucc.ernet.in
A fourth order nonlinear evolution equation is derived for a capillarygravity wave packet in deep water in the presence of a thin thermocline including the effect of wind and viscous dissipation in water. In deriving this equation it has been assumed that the wind induced basic current in water is exponential and the effect of shear in air flow and viscous dissipation in water is accounted for by including a term in the evolution equation. The nonlinear evolution equation is used to study the stability of a uniform capillarygravity wave train. Expressions for the maximum growth rate of instability and wave number at marginal stability are obtained. From results shown graphically it is found that the inclusion of wind effect increases the growth rate of instability irrespective of the presence of a thin thermocline. For waves with a small wave number, a thin thermocline has a stabilizing influence both in the presence and in the absence of wind input and the maximum growth rate of instability decreases with the increase of thermocline depth. But for waves with a large wave number a thin thermocline has no influence.

Key words: 
capillarygravity waves, evolution equation, instability, thermocline, wind input. 
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3.
EFFECTS OF HEAT AND MASS TRANSFER ON A MOVING VERTICAL CYLINDER WITH CHEMICALLY REACTIVE SPECIES DIFFUSION
P.GANESAN and P. LOGANATHAN
School of Mathematics, Anna University, Chennai  600 025, INDIA
email: ganesan@annauniv.edu
email: ploknath@hotmail.com
A numerical analysis is carried out to examine the combined heat and mass transfer along with chemical reaction characteristics in a free convective flow over a moving semiinfinite vertical cylinder. The governing equations are solved using an implicit finite difference scheme of CrankNicolson type. The effects of the chemical reaction in transient velocity, temperature, concentration, local and average skinfriction, Nusselt number and Sherwood number profiles are illustrated and discussed for various physical parametric values. It is observed that with an increase in the chemical reaction parameter K or the Schmidt number Sc, velocity decreases, but velocity increases with an increasing thermal Grashof number Gr or mass Grashof number Gc. The surface mass transfer strongly depends on the Schmidt number and the chemical reaction and it decreases with their increasing values.

Key words: 
chemically reactive species, moving cylinder, finitedifference equation. 
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4.
QUANTITATIVE ANALYSIS OF NONHOMOGENEITY OF THERMAL FIELDS FROM THERMAL IMAGES OF BUILDING PLASTERS
Z. GARNCAREK
University of Opole
ul. Oleska 48, 45234 Opole, POLAND
W. GRZESZCZYK and J. SZYMCZAK
Technical University of Opole
ul. St. Mikołajczyka 5, 45233 Opole, POLAND
email: jozefszym@poczta.onet.pl
The paper presents a method of quantitative analysis of disturbances in thermal fields homogeneity. The method has been used for calculations of the degree of nonhomogeneity of thermal fields from thermal images of specimens of building plasters. The thermal images were used for the analysis of relations between the mean contact temperature and the degree of disturbances of the thermal field homogeneity on the specimen surface as well as relations between the degree of the specimen roughness and disturbances of the thermal field on the specimen surface. It has been shown that disturbances of the thermal field homogeneity decrease as the mean contact temperature rises. The authors have formulated a hypothesis that disturbances of the thermal field homogeneity on the specimen surface rise as roughness rises (in the four cases under consideration an unfavourable result was obtained only once).

Key words: 
thermography, thermal field, measure of homogeneity disturbances, surfaces of building partitions. 
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5.
HALL EFFECTS ON MHD FLOW AND HEAT TRANSFER OVER A STRETCHING SURFACE
A.S. GUPTA, A. PAL, B. PAL
Mathematics Department, Indian Institute of Technology
Kharagpur 721302, INDIA
Email: asg@maths.iitkgp.ernet.in
H.S. TAKHAR
School of Engineering, University of Manchester
Manchester M129PL, UNITED KINGDOM
A magnetohydrodynamic (MHD) flow of an incompressible viscous electrically conducting fluid over a stretching surface is investigated when the fluid is permeated by a uniform transverse magnetic field and Hall effects are taken into account. It is found that for a flow at small magnetic Reynolds number past the surface which is stretched with a velocity proportional to the distance from a fixed point, velocity profiles are similar. For a fixed value of the Hall parameter m, components of velocity along and normal to the surface at a given point decrease with an increase in the magnetic parameter M. However for fixed values of m and M, the crossflow velocity component induced by Hall currents reaches a maximum value at a certain height from the surface and the profiles for this velocity component shift towards the left with an increase in M. A novel result of the analysis is that for a fixed value of M, the primary velocity component remains positive for small values of the Hall parameter (m=<0.5) and becomes negative for m>0.5 indicating flow reversal. The region of this flow reversal increases with an increase in m. A similarity solution for temperature distribution in the above flow is also found and the rate of heat transfer at the stretching surface is computed for various values of m and M.

Key words: 
magnetohydrodynamic, stretching surface, Hall effects, heat transfer. 
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6.
THE DIFFUSION OF HEAT AND MOISTURE THROUGH TEXTILES
A.K. HAGHI
Guilan University, College of Engineering
P.O. Box 3756, Rasht, IRAN
email: Haghi@guilan.ac.ir
An improved mathematical model that takes into account the water vapor sorption mechanisms of wool fiber is developed to describe and predict the coupled heat and moisture transport in wool fabrics.On the basis of the model, the moisturesorption mechanisms are investigated for fabrics made from fibers with different degrees of hygroscopicity. Theoretical predictions on the moisture uptake and temperature changes under humidity transients are compared with those measured previously in a sorptioncell experiment for fabrics made from wool, cotton, acrylic fiber, and polypropylene fiber. It is concluded that the physical mechanism of moisture diffusion into highly hygroscopic fibers such as wool and cotton can be described by a two stage moisture diffusion process.

Key words: 
moisture diffusion, hygroscopic fabrics, humidity transients. 
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7.
STATIC ANALYSIS OF ISOTROPIC THICK/THIN SKEW PLATES BY FINITE ELEMENT METHOD
S. HALDAR, M.C. MANNA
Department of Applied Mechanics
Bengal Engineering College (Deemed University)
Howrah  711 103, INDIA
email: mcmbecdu@lycos.com, mcmbecdu@yahoo.com
A.H. SHEIKH
Department of Ocean Engineering and Naval Architecture
Indian Institute of Technology
Kharagpur  721 302, INDIA
A general first order shear deformation theory has been developed to analyze the bending behavior of isotropic skew plates. The plates having different skew angles ('alpha'), aspect ratios (a/b), boundary conditions and transverse loading conditions (concentrated load, uniformly distributed load, hydrostatic varying load and sinusoidal varying load) have been analyzed by the nine node isoparametric element. The analysis has also been performed considering plate thickness ratio varying from a/b=0.001 to a/b=0.02. The deflections and principal bending moments in nondimensional forms have been presented at different locations of the plates. The present solutions have been compared with the published results wherever available and have got good agreement. Some numerical solutions have been given which may be treated as new results.

Key words: 
shear deformation, skew plate, hydrostatic and sinusoidal load, aspect ratio, thickness ratio. 
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8.
RHEOLOGICAL BEHAVIOR AND FATIGUE OF ALUMINUM OXIDE BASED COMPOSITE STRUCTURES ON SOFT SUBSTRATES
M. KIREITSEU
Institute of Machine Reliability (INDMASH NAS of Belarus)
National Academy of Sciences of Belarus, Lesnoe 1962, Minsk 223052, BELARUS
email: indmash@yandex.ru
The present paper describes rheological behavior and fatigue of novel composite systems "chrome carbide  aluminum oxide  aluminum" and "steel  soft polymer  aluminum  aluminum oxide". Rheological models of the composite systems have been proposed and confirmed by insitu experiments at Hertzian indentation. Load rating tests revealed ultimate stresses and stressdeformation modes of the systems. A possibility has been demonstrated of improving mechanical properties of aluminum oxidebased layers by CrC nanoparticles deposited by the metalorganic chemical vapor deposition. The CrC nanoparticles fill various surface defects of the aluminum oxide thus strengthening and toughening the system. High fracture resistance has been observed.

Key words: 
rheology, composite, aluminum oxide, fracture, mechanics. 
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9.
MAGNETIC FLUID BASED SQUEEZE FILM BEHAVIOUR BETWEEN ROTATING POROUS CIRCULAR PLATES WITH A CONCENTRIC CIRCULAR POCKET AND SURFACE ROUGHNESS EFFECTS
R.M. PATEL
Department of Mathematics, Gujarat Arts and Science College
Ahmedabad  380 006 Gujarat State, INDIA
email: jrmpatel@rediffmail.com
G.M. DEHERI
Department of Mathematics, Sardar Patel University
Vallabh Vidyanagar  388 120 Gujarat State, INDIA
Efforts have been made to analyze the magnetic fluid based squeeze film between rotating porous circular plates with a concentric pocket. The porous housing is considered to be elastically negligibly deformable with its contact surface rough. The stochastic film thickness characterizing the roughness is considered to be asymmetric with zero mean and nonzero variance. The modified Reynolds' equation is solved in order to get pressure distribution which in turn, is used to obtain the expression for load carrying capacity. Then by making use of this expression we find the response time. These expressions are numerically computed and the results are presented graphically as well as in a tabular form. It is observed that the presence of pocket and the roughness of the surfaces affect the performance of the bearing adversely. However, the performance of the bearing gets enhanced due to negatively skewed roughness and the magnetic fluid.

Key words: 
Reynold's equation, random roughness, magnetic fluid, squeeze film, load carrying capacity. 
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10.
SEMIACTIVE MAGNETORHEOLOGICAL SUSPENSION PERFORMANCE
G. QUAGLIA
Department of Mechanics, Politecnico di Torino
Corso Duca degli Abruzzi 24
10129 Torino, ITALY
email: quaglia@polito.it
For semiactive and active suspensions for automotive applications, passing from a theoretical law to an actual design with components capable of implementing the desired theoretical force laws is always a critical point. Indeed, many systems that can generate forces are both complex and limited as regards their frequency response, and this is particularly true for active systems.
This investigation addresses the problem of whether a theoretical semiactive force law can actually be implemented by using a magnetorheological damper, obtaining the desired results from the suspension.
The paper presents a comparative method for analyzing different vehicle suspensions in order to determine whether a magnetorheological device can actually implement theoretical damping laws.
This study concludes with a discussion of simulation results, which provide a good idea of the limitations and potential of magnetorheological technology for application in motor vehicle suspensions.

Key words: 
semiactive suspensions, magnetorheological, vehicle, dynamics, mechatronics. 
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11.
ON THE WAVE PROPAGATION IN GENERALISED THERMOELASTIC MEDIA
J.N. SHARMA
Department of Mathematics, Regional Engineering College
Hamirpur  177 005, INDIA
email: jns@recham.ernet.in
P.K. SHARMA
Department of Mathematics, GGSSS, Dharamsala
Himachal Pradesh  176 215, INDIA
S.K. GUPTA
Department of Mathematics, Himachal Pradesh University
Shimla  171 005, INDIA
In this paper, the analysis is based on the decoupled field equations of linear thermoelasticity without energy dissipation. These equations have been solved with the use of integral transforms. The dynamic behavior of an elastic half space due to (i) a line load and (ii) a mechanical load, acting on the boundary is also discussed. While the displacement in both of the cases is found to be continuous, the temperature, strain and stress are observed to be discontinuous at elastic and thermal wave fronts. The characteristic features of the underlying theory are analyzed in the light of these solutions and their counterparts in earlier works. The results obtained theoretically have been computed numerically and are represented graphically.

Key words: 
Cagniard method, conformal mapping, wave fronts, second sound, epicentral distance. 
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12.
A FRICTION MODEL OF MICROBEARINGS WITH THIN METALLIC COMPLIANT COATINGS
I. STIHARU, R. BHAT and H. HONG
Department of Mechanical Engineering, Concordia University
1455 de Maisonneuve Blvd. West, Montreal, H3G 1M8
Quebec, CANADA
email: istih@alcor.concordia.ca
The paper presents experimental results of the investigation on the microtribological properties of Ti thin film layers deposited on metallic substrates of various hardness. The tests were carried out under standard dry friction conditions using a miniature pin on disk apparatus. The experimental results found for the friction coefficient developed between 52100 steel pin and Ti as a compliant layer deposited on various hardness substrates from soft to hard are consistent with other results presented in literature for the pair steel/Ti.
A friction model that assumes the plowing of microasperities into the soft thin film layer supported by the elastic substrate as the main factor in the originating friction is further proposed.
A simplified oneasperity model is assessed against the compliant layer assumed deposited on a rigid substrate. The analysis of the influence of the stress developed at the interface substratefilm is assumed in this model. Tests carried out qualitatively confirmed that the influence of the interlaminar stress is significant to friction. Given the simplification assumptions, the proposed model exhibits reasonable agreement with the experimental results.
It is further suggested that the lubrication of the hard surfaces with thin compliant metallic layers of Ti represents an alternative for the friction improvement in the small bearings belonging to miniature mechanical systems and the MicroElectroMechanical Systems (MEMS).

Key words: 
microbearings, Ti thin film coatings, friction coefficient, experimental validation. 
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13. Brief note
MAGNETIC FLUID BASED POROUS INCLINED SLIDER BEARING WITH VELOCITY SLIP
RAJESH C. SHAH
Department of Mathematics, Nirma Institute of Technology
GandhinagarSerkhej Highway, Post. Chandlodia
Ahmedabad  382 481, Gujarat State, INDIA
email: dr_rcshah@yahoo.com
M.V. BHAT
E202, Riddhi Complex, Near Jodhpur Village
Ahmedabad  380 015, Gujarat State, INDIA
A theoretical study was made of a porous inclined slider with a magnetic fluid as lubricant considering velocity slip. Expressions were obtained for pressure, load capacity, friction on the moving slider, the coefficient of friction and the position of the centre of pressure. Computed values showed that load capacity and friction decreased when the slip parameter increased. The coefficient of friction attains an optimum for a certain value of the slip parameter which affects a little the position of the centre of pressure.

Key words: 
magnetic fluid, lubrication, porous, inclined slider, slip. 
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