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VOLUME 15CODEN : IEMSEW 
NUMBER 5

OCTOBER 2008 ISSN : 09714588 
Engineering 

Particle tracking in rotating channel
flow 
365 
Krishnan
V Pagalthivarthia & Pankaj K Gupta 

Ferrography — A procedure
for measuring wear rate 
377 
^{ } 
^{ } 
Micromechanical analysis of FRP
hybrid composite lamina for inplane transverse loading 
382 
K
Sivaji Babu, K Mohana Rao, V Rama Chandra Raju, V Bala Krishna Murthy & M S R Niranjan Kumar 

On the
calculation of derivatives of stress intensity factors using fractal finite
element method 
391 
^{ } 
^{ } 
Materials Science 

Synthesis and characterization of
boron nitride nanotubes using a simple chemical method 
419 
S
K Singhal, A K Srivastava, B P Singh & Anil K Gupta 

Effect of variation of PVP/PVA weight
ratio on the behaviour of nanocrystalline silver 
425 


A selfsustaining reaction for
titanium aluminides production via aluminocalciothermic reduction of TiO_{2} 
429 


Characterization of fly ash and it
effects on the compressive strength properties of 
433 

Indian
Journal of Engineering & Materials Sciences
Vol.
15, October 2008, pp. 365376
Particle tracking in rotating channel flow
Krishnan V Pagalthivarthi^{ }& Pankaj K Gupta^{}
The study deals with the numerical simulation of dilute solidfluid flow in a twodimensional straight rotating channel using Lagrangian particle tracking method. The developing carrierphase flow, assumed to be steady in the mean, is computed using Galerkin finite element method. A rotationmodified ke model is used to account for the effect of turbulence on the mean flow.
Oneway coupling is assumed, i.e., the carrierphase flow affects the particle motion, but not viceversa. Model coefficients of restitution in the normal and tangential directions are used. The particle equations of motion include drag, pressure, centrifugal, Coriolis, virtual mass, and friction (in case the particle slides along the wall) forces. Mesh refinement and comparison with published numerical results are used to validate the code. Effects of such operating parameters as rotation rate, particle size, specific gravity and coefficients of restitution are discussed.
Indian
Journal of Engineering & Materials Sciences
Vol.
15, October 2008, pp. 377381
Ferrography — A procedure for measuring wear rate
A contact fatigue phenomenon is most common failure seen in the structural components, which are under highcyclic fatigue loads. Rail wheels, mating gears, ball bearing and wherever the formal contact between the two structural elements, are affected by contact fatigue failure, is commonly referred as pitting of surface. It can be seen that those structural elements are manufactured by powder metallurgy technology since it has more technical as well as commercial advantages over the conventionally made structural parts. Development in powder metallurgy manufacturing technologies, will give us confident to use of more powder metallurgy structural parts in place of conventional parts. Rollingsliding contact fatigue (RSCF) experiments on powder metallurgy (PM) steels have been carried out in the laboratories with available experimental setup. The lubrication oil is collected for regular interval and ferrography test is involved to predict the wear rate of the powder metallurgy steels. Wear morphology of porous steel is predicted.
Indian
Journal of Engineering & Materials Sciences
Vol.
15, October 2008, pp. 382390
Micromechanical analysis of FRP hybrid composite lamina for
inplane transverse loading
K Sivaji Babu, K Mohana Rao, V Rama Chandra Raju, V Bala Krishna Murthy^{ }& M S R Niranjan Kumar
In this paper, the micromechanical behaviour of the square unit cell of a hybrid fiber reinforced composite lamina consisting of graphite and boron fibers embedded in epoxy matrix, has been studied. A threedimensional finite element model with governing boundary conditions has been developed from the unit cells of square pattern of the composite to predict the Young’s modulus (E_{2}) and Poisson’s ratios (ν_{21} and ν_{23}) of graphiteboron hybrid fiber reinforced lamina for various volume fractions. The stresses at the fibermatrix interfaces induced due to the inplane transverse loading, that is applied to predict the inplane transverse Young’s modulus (E_{2}) and the associated Poisson’s ratios, are also determined from these models. The finite element software ANSYS has been successfully executed to evaluate the properties and stresses. The variation of the stresses at the fibermatrix interface with respect to the angular location is discussed. The Young’s modulus is found to be increasing with V_{f} indicating that the stiffness of the composite increases with V_{f }, The magnitude of the normal stresses at the fiber matrix interface are maximum at θ = 0° as the direction of the load is normal to the surface at this location. This may result in the separation of fiber and matrix leading to debonding. This analysis is useful to realize the advantages of hybrid fiberreinforced composites in structural applications, and to identify the locations with reasons where the stresses are critical to damage the interface.
Indian Journal of Engineering
& Materials Sciences
Vol. 15, October
2008, pp. 391418
On the calculation of
derivatives of stress intensity factors
using fractal finite element method
R M Reddy & B N Rao
This paper presents a new fractal finite element based method for continuumbased shape sensitivity analysis for a crack in a homogeneous, isotropic, and two dimensional linearelastic body subject to mixedmode (modes I and II) loading conditions. The method is based on the material derivative concept of continuum mechanics, and direct differentiation. Unlike virtual crack extension techniques, no mesh perturbation is needed in the proposed method to calculate the sensitivity of stressintensity factors. Since the governing variational equation is differentiated prior to the process of discretization, the resulting sensitivity equations predict the firstorder sensitivity of the stressintensity factors, K_{I} and K_{II}, more efficiently and accurately than the finitedifference method. Unlike the integral based methods such as Jintegral or Mintegral no special finite elements and postprocessing are needed to determine the firstorder sensitivity of the stressintensity factors, K_{I} and K_{II}. Also a parametric study is carried out to examine the effects of the similarity ratio, the number of transformation terms, and the integration order on the quality of the numerical solutions. One mixed mode numerical example is presented to calculate the firstorder derivative of the stressintensity factors. The results show that the firstorder sensitivities of the stress intensity factors obtained using the proposed method are in excellent agreement with the reference solutions obtained using the finitedifference method.
Indian
Journal of Engineering & Materials Sciences
Vol.
15, October 2008, pp. 419424
Synthesis and
characterization of boron nitride nanotubes using a simple
chemical method
S K Singhal, A K Srivastava, B P Singh & Anil K Gupta
A simple twostep process is used for the growth of high purity multiwalled boron nitride (BN) nanotubes. In the first step, disordered nanostructured BN powder (aBN) is prepared chemically by heating a powdered mixture of KBH_{4 }and NH_{4}Cl (1:1) at 850ºC in N_{2} followed by quenching the reaction product. In the second step, BN nanotubes are grown from the asprepared aBN powder by annealing it at about 12001300ºC for 510 h in N_{2}. No catalyst material (Fe, Ni, Co, etc.) is intentionally added to aBN powder. This method of synthesis resulted in high purity multiwalled BN nanotubes of almost uniform diameter (1030 nm) and length up to 5 µm, and, thus has a high aspect ratio with inherent characteristics of BN nanotubes, which may be useful for different applications. The BN nanotubes have been characterized using various techniques including Xray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The results obtained by this process are also compared with the similar type of BN nanotubes produced employing ballmilling and annealing technique.
Indian
Journal of Engineering & Materials Sciences
Vol.
15, October 2008, pp. 425428
Effect of variation of PVP/PVA weight ratio on
the behaviour of nanocrystalline silver
Manab Mallik & R K Mandal
The effect of polyvinylpyrrolidone/polyvinylalcohal (PVP/PVA) weight ratio on the resulting size and shape of nanocrystalline (NC) silver is presented. It is shown that all the NC silver samples investigated, in this study, have displayed face centered cubic structure. The average coherently scattering domain size is estimated with the help of Scherrer equation. Having computed this, an attempt has been made to understand the UVVis spectra of the NC sols in terms of localized surface plasmon resonance (LSPR) behaviour. The change in the nature of LSPR in visible range of spectrum of the sols has been attributed to the complex interplay of shape, size and distribution of NC silver.
Indian
Journal of Engineering & Materials Sciences
Vol.
15, October 2008, pp. 429432
A selfsustaining reaction for titanium aluminides production via aluminocalciothermic reduction of TiO_{2}
Ali Reza Kamali
Titanium aluminides can be produced via an
aluminocalciothermic reduction of TiO_{2} in presence of KClO_{4}.
This reaction, named KRH process, has been studied in this paper. The results
show that after heating of starting materials with rate of 20°C/min, a selfsustaining
reaction is ignited at about 550°C which
led to the rapid increasing of system temperature to
Indian
Journal of Engineering & Materials Sciences
Vol.
15, October 2008, pp. 433440
Characterization of fly ash and it effects on the compressive
strength
properties of Portland cement
Özlem Çelik, Erdem Damcı & Sabriye Pişkin
In this study, the structure of different type of fly ash samples
collected from different thermal power plants (Soma Unit IV/ type C, Çatalagzi/type
F, Çayırhan / type C, Tunçbilek/ type F) in