Indian Journal of Engineering & Materials Science

 

 

Total visitors: 1,535  since 21-02-07

 

 

VOLUME 14

CODEN : IEMSEW

NUMBER 1

FEBRUARY 2007

ISSN : 0971-4588

 

CONTENTS

 

Engineering

 

 

Study of surface roughness in squeeze casting LM6 aluminium alloy using Taguchi method

 

7

        P Vijian, V P Arunachalam & S Charles

 

        [IPC Code: C22C 21/00]

 

 

Flow characteristics in a transition duct passing from rectangular section to circular section

 

12

        Hasan Gül & Duygu Evin

 

        [IPC Code: G01F 1/05]

 

 

A study on damages in alloyed super heater tubes of thermal power station

19

        M Azad Sohail & A Ismail Mustafa

 

        [IPC Code: C21D 1/00]

 

 

Failure cause analysis of welded joints

24

        Rakesh Sehgal, Surjit Angra & Vinod Sharma

 

        [IPC Code: B23K]

 

 

A modified quarter point element for fracture analysis of cracks

31

        Sayantan Paul & B N Rao

 

        [IPC Code: G01N]

 

 

Pavement rutting characterization using deflection basin parameters

39

        Kasthurirangan Gopalakrishnan & Marshall R Thompson

 

        [IPC Code: E01C 9/00]

 

 

Studies on mitigation of moisture damage in bituminous pavements

48

        P K Jain & J B Sengupta

 

        [IPC Code: E01C 7/18]

 

 

Materials Science

 

 

Effect of process conditions on microstructure and performance of thermally evaporated InSb thin films

 

55

        Sukhvir Singh, Kasturi Lal, A K Srivastava, K N Sood & Ram Kishore

 

        [IPC Code: H01C 17/065]

 

Electrical and dielectric properties of double doped BaTiO3

64

        Md A Mohiddon, P Goel, K LYadav, M Kumar & P K Yadav

 

        [IPC Code: G01R 27/26, G01N 33/38]

 

 

Hydration of bamboo leaf ash blended Portland cement

69

        N B Singh, S S Das, N P Singh & V N Dwivedi

 

        [IPC Code: C04B 7/02]

 

 

Theoretical prediction of detonation pressure of CHNO high energy materials

77

        M H Keshavarz

 

        [IPC Code: C06B]

 

Design of Routh column polynomials for instability analysis of linear time invariant continuous systems

 

81

        S N Sivanandam & S N Deepa

 

        [IPC Code: G01R 31/02]

 

______________

 

IPC: International Patent Classification

 

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

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 14, February 2007, pp. 7-11

 

 

Study of surface roughness in squeeze casting LM6 aluminium alloy using Taguchi method

 

P Vijian, V P Arunachalam & S Charles

 

Squeeze casting combines the strength and integrity of forging with the economy and design flexibility of casting to produce components with better surface finish. The primary aim of this study was to analyze the influence of the process parameters on surface roughness in squeeze casting of LM6 aluminium alloy using Taguchi method. A three level orthogonal array L9 (34) was used to determine the S/N ratio (dB), and analysis of variance (ANOVA). The most significant process parameters affecting the surface roughness were identified using F  test. The results indicated that squeeze pressure and die pre-heating temperature were the parameters responsible for causing appreciable improvement in the surface finish of the squeeze cast components.

IPC Code: C22C21/00

 

  

Indian Journal of Engineering & Materials Sciences

Vol. 14, February 2007, pp. 12-18

 

 

Flow characteristics in a transition duct passing from rectangular
section to circular section

 

Hasan Gül & Duygu Evin

 

The characteristics of a flow in a transition duct, in which the flow passes from a rectangular cross-section to a circular one, were investigated experimentally. The transition duct had an entry aspect ratio of 0.65 and exit aspect ratio of 1. The experiments were conducted at three different channels which have different lengths. The exit cross-sectional area of the transitional duct was double of the inlet. Reynolds number varied in the range of 2×105-6×105. Local pressures and velocities were measured along the duct.

IPC Code: G01F1/05

Indian Journal of Engineering & Materials Sciences

Vol. 14, February 2007, pp. 19-23

 

 

A study on damages in alloyed super heater tubes of thermal power station

M Azad Sohail & A Ismail Mustafa

 

In this paper, an investigation on the damages in alloyed super heater and reheater tubes materials for natural circulation water wall tubes (NCWWTs) high-pressure drum boiler units TGME-COB-206 (Russia) of Ghorasal Thermal Power Station (GTPS), Bangladesh, have been carried out at different schedule maintenances. Extensive analyses of different chemical parameters of boiler water chemical regime (BWCR), and generated steam (live) quality at rated operating steam temperature and pressure, revealed carryover of SiO2 20 (±5) mgL-1 in steam (live) during cold startup and abrupt increase in thermal load of boiler unit. The micro and macro structural examinations of super heater tube materials, scale composition; scale thickness and composition of super heater tubes materials have been monitored very carefully. Silica is found to be the major component for the super heater scaling which has strong affinity to the chromium containing steel reheater tubes materials.

IPC Code: C21D 1/00

Indian Journal of Engineering & Materials Sciences

Vol. 14, February 2007, pp. 24-30

 

 

Failure cause analysis of welded joints

Rakesh Sehgal, Surjit Angra & Vinod Sharma

 

Failure of welded structures/machine components lead to various direct losses such as the cost of repair work, the cost of the work to prevent future failure and accident compensation, and indirect losses such as decrease in production and a damage to company’s image. Joints being the weakest elements in any structure/machine are likely to fail first. It is, therefore, imperative to understand the failure of these joints. Understanding a failure occurrence and its propagation will lead to a better appreciation of welded joints from reliability point of view. It may be possible that a few cause events or failure causes may be crucial and could be minimized at design or fabrication stage leading to failure minimization of such joints. In this paper, a procedure based on digraph modeling and matrix approach is suggested for failure analysis of welded joints. The failure logic digraph for welded joint (WLFLD) is defined which considers contributing cause events and their interrelations. The digraph is analysed using connection and reachability matrices. Welded joint failure connection matrix (WJFCM) is obtained for the welded joint failure logic digraph and welded joint failure reachability matrix (WJFRM) is derived from it which helps in identifying the stage relationship among various cause events and evaluate the importance of the cause events for the failure modes. It, therefore, provides direction for appropriate action for minimization of failure mode thus improving the reliability of the joints.

IPC Code: B23K

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 14, February 2007, pp. 31-38

 

A modified quarter point element for fracture analysis of cracks

 

Sayantan Paul & B N Rao

 

A modification to the quarter-point crack tip element for the computation of stress intensity factors in cracked plates subjected to mixed mode loading is presented. The standard quarter-point singular element is modified such that the near tip crack opening displacement satisfies a known constraint; the coefficient of the term in William’s expression which is a linear function of the distance to the tip must vanish in order to have the singularity at the crack tip. Stress intensity factors computed using the modified quarter-point crack tip element in conjunction with the displacement correlation technique gives better results as compared to those obtained by the standard quarter-point element. The technique basically involves the same guidelines as that of the standard quarter-point element, where 6-noded quarter-point elements are adopted to mesh the singular region around the crack tip and 8-noded quadrilateral elements are adopted to mesh rest of the non-singular region. Based on the shape functions of the proposed modified quarter-point crack tip element the equations for computing the crack tip opening displacement and the stress intensity factors are presented taking into account the nodal displacement values of the elements around the crack tip. The results obtained using the modified quarter-point crack tip element are shown to be significantly more accurate than those obtained using the standard quarter-point element for both mode-I and mixed-mode problems.

IPC Code: G01N

Indian Journal of Engineering & Materials Sciences

Vol. 14, February 2007, pp. 39-47

 

 

Pavement rutting characterization using deflection basin parameters

 

Kasthurirangan Gopalakrishnan & Marshall R Thompson

 

The U.S. Federal Aviation Administration’s National Airport Pavement Test Facility (NAPTF) was constructed to generate full-scale traffic test data to support the development of advanced airport pavement design procedures. During the first series of traffic tests, a six-wheel Boeing 777 gear and a four-wheel Boeing 747 gear were tested on flexible pavements until they were deemed failed. Heavy Weight Deflectometer (HWD) tests were conducted prior to and throughout the traffic testing to assess the structural integrity of pavements. An inertial profiling device was used to measure the transverse surface profiles periodically during the traffic testing to monitor the development of rut depths. The NAPTF rutting data were characterized using the simple Power model. In this study, regression models were developed to obtain the rutting model parameters, in terms of rutting potential and rutting rate, as functions of initial HWD surface deflections. The results indicated that the rutting potential is strongly related to initial surface deflections. If the rutting model (Power model) coefficients can be related to HWD structural responses, a viable rutting algorithm can be developed for use in a priori airport pavement design and management activities.

IPC Code: E01C9/00

 

Indian Journal of Engineering & Materials Sciences

Vol. 14 February 2007, pp. 48-54

 

Studies on mitigation of moisture damage in bituminous pavements

 

P K Jain & J B Sengupta

 

The process of stripping failure of aggregate-bitumen system in presence of water is accelerated by ions of salts and is thus responsible for early failure of open graded bituminous courses in salt infected areas. A quantitative assessment of stripping is not possible by available methods. The aim of this paper is to demonstrate mitigation of moisture damage in bituminous pavements using long chain fatty acid amine based additives. Results of studies reported in this paper indicate that measurement of indirect tensile strength under specified conditions of moisture soaking and immersion correlate well with stripping area of aggregates to the extent of 90-100%. Incorporation of 0.5% dehydrogenated tallow di methyl amine in bitumen prevents stripping of aggregates in presence of detrimental salt ions. Hence, failure of bituminous courses in salt infected areas can be prevented using these additives and life of surfacing can be extended. Indirect tensile strength ratio of Marshall specimen of open graded mix can be considered for quantitative assessment of stripping phenomenon.

IPC Code: E01C7/18

Indian Journal of Engineering & Materials Sciences

Vol. 14, February 2007, pp. 55-63

 

Effect of process conditions on microstructure and performance of thermally evaporated InSb thin films

Sukhvir Singh, Kasturi Lal, A K Srivastava, K N Sood & Ram Kishore

 

Technologically important Indium Antimonide (InSb) thin films have been grown on different substrates (NaCl, KCl, KBr, quartz and glass) maintained at varied temperatures (300, 373, 473, 623 and 703 K) using a thermal evaporation technique under vacuum (~10-3 Pa). These films have been prepared by utilizing a single phase stoichiometric InSb compound produced by vertical directional solidification (VDS) technique. Scanning and transmission electron microscopy (SEM & TEM), X-ray diffraction (XRD), fourier transform infrared spectrometry (FTIR) and electrical resistivity measurements are the important characterization methods used for analyzing these films deposited under different process conditions. The conditions have been determined to deposit good quality epitaxial films of InSb. The effect of the type of substrate and its temperature on the quality of thin films in terms of their structure and microstructure and different properties has been evaluated.

IPC Code: H01C 17/065

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 14, February 2007, pp. 64-68

 

Electrical and dielectric properties of double doped BaTiO3

Md A Mohiddon, P Goel, K LYadav, M Kumar & P K Yadav

 

Alkali (Li, Na, K) and lanthanum doped barium titanate has been prepared by solid-state reaction method. X-ray diffraction studies suggest the compound is in tetragonal phase with small change in c/a ratio. Detailed studies of dielectric constant as a function of temperature (40-300°C) and frequency (100 Hz-1 MHz) suggest that the compounds do not have relaxor behaviour and undergoes diffuse type of phase transition. Curie temperature is found to be independent of type of alkali doping and measuring frequency. However, maximum dielectric constant and resistivity are found to be strongly dependent on frequency and type of doping.

IPC Code:  G01R27/26, G01N33/38

 

Indian Journal of Engineering & Materials Sciences

Vol. 14, February 2007, pp. 69-76

 

Hydration of bamboo leaf ash blended Portland cement

N B Singh, S S Das, N P Singh & V N Dwivedi

 

Bamboo leaf ash (BLA) obtained at 600oC was found to be pozzolanic material. The pozzolanic activity was studied by using chemical methods, differential scanning calorimetry, X-ray diffraction and scanning electron microscopic techniques. Hydration behaviour of 20 wt% BLA blended ordinary Portland cement (OPC) was studied by using different experimental techniques and it was found that at 28 days of hydration the compressive strength value for 20 wt% BLA blended cement mortar was quite comparable to that of mortar made from OPC. The mechanism of pozzolanic activity has been discussed.

IPC Code:  C04B7/02

Indian Journal of Engineering & Materials Sciences

Vol. 14, February 2007, pp. 77-80

 

 

Theoretical prediction of detonation pressure of CHNO high energy materials

M H Keshavarz

 

A new simple method has been introduced to calculate maximum obtainable detonation pressure of any pure or mixed CHNO explosives. There is no need to use heat of formation and crystal density of explosive in this procedure. It is shown here how the atomic composition and structural parameters can be integrated into an empirical formula for predicting the detonation pressure of proposed explosives. Maximum performance obtained by new procedure for both pure and explosive formulations show good agreement with respect to measured detonation pressure.

IPC Code: C06B

Indian Journal of Engineering & Materials Sciences

Vol. 14, February 2007, pp. 81-86

 

Design of Routh column polynomials for instability analysis of linear time invariant continuous systems

 

S N Sivanandam & S N Deepa

 

The analysis of unstable linear time-invariant continuous systems, employing the elements of columns from Routh table is brought out in this work. A linear time invariant continuous system represented in the form of characteristic equation can be analyzed for stability or instability with the help of Routh table. The elements of this table are generated using Routh multiplication rules and the sign changes in the first column, as well sign change anywhere in the table indicates unstable situation. If the sign change occurs at the end of the first column, it involves more computation. As a result, in this work, the other columns of the Routh array are studied, based on which Pseudo-Routh Polynomials are constructed and the instability is analyzed. It is to be noted that the information residing from the last column only traverses towards the first column. If the instability analysis is obtained from last column or last but one column itself, the entire Routh array need not be constructed, which helps in easier computation in higher degree polynomials. Examples are given to illustrate the proposed scheme.

IPC Code:G01R31/02