Indian Journal of Engineering & Materials Sciences

VOLUME 8

NUMBER 2

APRIL 2001

 

CONTENTS

 

Engineering

 

Experimental investigation of wave forces on submerged horizontal cylinders

59

  Gazi Md. Khalil

 

 

 

Shear behaviour of jointed rockmass of sandstone quarry, Mizoram State, India

66

  T N Singh, M Monjezi, C Sawmliana & S Kumar

 

 

 

Vertical cracks of structural concrete beams under short-term load with unloading

71

  Terezia Nurnbergerova, Martin Krizma & Jan Hajek

 

 

 

Effects of non-uniform temperature gradient and magnetic field on the onset of convection in fields with suspended particles under microgravity condition

77

  P G Siddheshwar & S Pranesh

 

 

 

Hold-up in multi-sized particulate solid-liquid flow through horizontal pipes

84

  V Seshadri, S N Singh, Charau Fabien & R Mishra

 

 

 

Materials Science

 

Manufacturing of small sized fibre reinforced concrete boats

90

  A Rahim & M reaz H Khondoker

 

 

 

Treated fly ash : A potential catalyst for catalytic cracking

100

  Keka Ojha & Narayan C Pradhan

 

 

 

Kinetics of photocatalytic degradation of textile dye reactive red 2

104

  M V Shankar, B Neppolian, Banumathi Arabindoo, M Palanichamy &

 

        V Murugesan

 

 

 

Effect of sodium sulphate on the hydration of granulated blast furnace slag blended portland cement

110

  Neelam Singh, Sarita Rai & N B Singh

 

 

 

Conference Report

 

Sintering 2000 : Conference Report

114

  G S Upadhyay

 

 

 

Book Review

118

Material Marvels

 

  by B C Sharma; reviewed by C S Gupta

 

 


Indian Journal of Engineering & Materials Sciences

Vol. 8, April 2001, pp. 59-65

 

Experimental investigation of wave forces on submerged horizontal cylinders

 

Gazi Md. Khalil

Department of Naval Architecture and Marine Engineering, Bangladesh University of Engineering and Technology,
Dhaka 1000, Bangladesh

Received 27 March 2000; accepted 4 January 2001

This paper presents the results of an experimental investigation of the wave-induced forces acting on horizontal cylinders submerged beneath water waves with axis parallel to the wave crests. The experiments are carried out in a towing tank of the University of Tokyo. A flap-type wave generator is used to produce regular sinusoidal waves of length 1.57 and 3.14 m. The experiments are performed with a circular cylinder and a rectangular cylinder separately with a view to predicting the effect of geometry of the cylinder on the wave-induced forces. Each cylindrical model is tested at eight different depths of submergence. A multi-component load cell is used for the measurement of forces acting on the submerged cylinder. The measured forces are instantaneously digitized and stored in a transient memory. A personal computer , viz., PC 9801 is installed on the carriage of the towing tank in order to compute the mean forces right at the time of performing the experiments. The time-averaged mean horizontal as well as vertical forces acting on the cylindrical model at various depths of submergence are plotted and then physically interpreted. The results are compared with the available data in the literature. The principal conclusion of this investigation is that the breaking of waves behind a shallowly submerged cylinder is primarily responsible for the generation of non-linear wave forces. The negative drifting force which acts on a shallowly submerged cylinder is a direct consequence of wave-breaking. This drifting force, however, tends to vanish when the cylinder is deeply submerged. The findings of this investigation are expected to be useful in the accurate assessment hydrodynamic loads acting on various types of offshore structures.


Indian Journal of Engineering & Materials Sciences

Vol. 8, April 2001, pp. 66-70

 

Shear behaviour of jointed rockmass of sandstone quarry, Mizoram state, India

T N Singha, M Monjezia, C Sawmlianab & S Kumarc

aDepartment of Mining Engineering, Institute of Technology, Banaras Hindu University, Varanasi 221 005, India

bCentral Mining Research Institute, Barwa Road, Dhanbad 826 001, India

cDepartment of Geology, North Eastern Hill University (PUC Campus), Aizawl 796 001, Mizoram, India

Received 23 December 1999; accepted 20 December 2000

The shear behaviour of jointed rockmass in a sandstone quarry of south Hlimen, Mizoram were investigated for the slope stability analysis. A computer program was developed in ‘C’ language, to predict the shear strength and dilation of rock joints, based on Barton-Bandis Model. The program further helps to obtain field equivalents of physico-mechanical properties of such rock joints by using laboratory test data. Detailed joints survey were carried out in the field and basic geotechnical description (BGD) of the rockmass was described for rock joints as per recommendations of International Society for Rock Mechanics (ISRM). Tilt apparatus was used to determine the angles of tilt for the natural joint surfaces as well as for the smooth core samples. Jointwall compressive strength (JCS) and uniaxial compressive strength (UCS) of intact rock were also determined by using Schmidt’s hammer. The present study showed that the shear behaviour of the rock joints influenced by many factors, among which joint roughness, level of normal effective stress and size of blocks (joint spacing) are of paramount importance.


Indian Journal of Engineering & Materials Sciences

Vol. 8, April 2001, pp. 71-76

 

Vertical cracks of structural concrete beams under short-term load with unloading

Terezia Nürnbergerová, Martin Križma & Ján Hájek

Institute of Construction and Architecture, Slovak Academy of Sciences

Dúbravská cesta 9,  842 20  Bratislava, Slovak Republic

Received 25 July 2000; accepted 5 January 2001

Characteristics of the process of cracking have been studied and their evaluation based on the experimental investigation of reinforced and prestressed concrete beams subjected to short term load with unloading has been carried out. The relations between strains and the characteristics of cracking are explained in the paper. The relationship between the reversible part of crack opening density and the crack opening density immediately before unloading is also presented.


Indian Journal of Engineering & Materials Sciences

Vol. 8, April 2001, pp. 77-83

 

Effects of non-uniform temperature gradient and magnetic field on the onset of convection in fluids with suspended particles under microgravity conditions

P G Siddheshwar a* & S Praneshb

a Department of Mathematics, Bangalore University, Central College Campus, Bangalore 560 001, India

b Department of Mathematics, Christ College, Hosur Road, Bangalore 560 029, India

Received 9 March1999; revised received 13 December 2000

The effects of a non-uniform temperature gradient and magnetic field on the onset of convection driven by surface tension in a horizontal layer of Boussinesq fluid with suspended particles confined between an upper free / adiabatic boundary and a lower rigid / isothermal boundary have been considered. A linear stability analysis is performed. The microrotation is assumed to vanish at the boundaries. The Galerkin technique is used to obtain the eigenvalues. The influence of various parameters on the onset of convection has been analysed. Six different non-uniform temperature profiles are considered and their comparative influence on onset is discussed. It is observed that the electrically conducting fluid layer with suspended particles heated from below is more stable compared to the classical electrically conducting fluid without suspended particles. The critical wave number is found to be insensitive to the changes in the parameters but sensitive to the changes in the Chandrasekhar number. The problem has possible applications in microgravity space situations.

 


Indian Journal of Engineering & Materials Sciences

Vol. 8, April 2001, pp. 84-90

 

Hold-up in multi-sized particulate solid-liquid flow through horizontal pipes

 

V Seshadri1, S N Singh1, Charau Fabien2 & R Mishra3

1Applied Mechanics Department, Indian Institute of Technology, Hauz Khas, New Delhi 110 016, India

2Universite de Technologie de Compiegne, France

3Applied Mechanics Department, Moti Lal Nehru Regional Engineering College, Allahabad, India

 

Received 20 July 2000; accepted 5 March 2001

 

Hold-up is an important design parameter for pipelines transporting solid liquid mixture as it correctly determines the in situ volume fraction of different phases. Extensive experiments have been reported to establish the effect of solid concentration, flow velocity and particle size on hold-up. Based on the data base, a simple correlation has been proposed for determination of hold-up for multi-sized solid-liquid flow through pipes. The proposed correlation   [HR = 1+ 0.64(Wo / U*)1.50] incorporates the effect of all the factors affecting hold-up such as solid concentration, flow velocity, particle size, pipe diameter, etc. The predictions based on the proposed correlation match reasonably well with the experimental data.


Indian Journal of Engineering & Materials Sciences

Vol. 8, April 2001, pp. 90-99

 

Manufacturing of small sized fibre reinforced concrete boats

 

A Rahim & M Reaz H Khondoker

Department of Naval Architecture and Marine Engineering, Bangladesh University of Engineering and Technology,
 Dhaka-1000, Bangladesh

Received 24 January 2000; revised received 25 August 2000

The use of fibre as reinforcement in concrete is receiving considerable attention and the activity level is not confined to laboratory research only. Its acceptance by the designer, specifier, owner and contractor is very positive in developed countries. Very thin section concrete having good mechanical properties and properties like impact abrasion resistance have been achieved using fibre reinforcement. This paper reports the outcome of experiments involving design and manufacturing of small boats using fibre reinforced concrete. It is seen from the study that, fibre reinforced concrete boats are less expensive and of improved quality in comparison with the wooden ones. The short term performance of the boats built with this material has shown no structural or material weakness. It is recommended that based on the outcome of the works, follow up actions be undertaken to establish the material as a viable alternative boat-building material. It is further emphasized that evolution of this material as alternative to wood in building small boats will help the boat owners and help preserve environment.


Indian Journal of Engineering & Materials Sciences

Vol. 8, April 2001, pp. 100-103

 

 

 

Treated fly ash: A potential catalyst for catalytic cracking

Keka Ojha & Narayan C Pradhan*

Department of Chemical Engineering, Indian Institute of Technology, Kharagpur 721 302, India

Received 25 August 2000; accepted 19 February 2001

Fly ash from a Thermal Power Plant was converted to zeolite by alkali fusion followed by  hydrothermal treatment. The formation of zeolite was confirmed by X-ray diffraction and scanning electron microscopy. The performance of the prepared zeolite as cracking catalyst was tested by carrying out cracking of a heavy crude residue. Cracking of the same feed was also carried out with raw (untreated) fly ash and commercial 13X zeolite. At 11 wt% catalyst loading, temperature 380oC and atmospheric pressure, the feed conversions to lighter products (bp £ 250oC) obtained were 35.6%, 58% and 58% with raw fly ash, treated fly ash and commercial zeolite, respectively, as the catalyst.


Indian Journal of Engineering & Materials Sciences

Vol. 8, April 2001, pp. 104-109

 

Kinetics of photocatalytic degradation of textile dye reactive red 2

M V Shankar, B Neppolian, S Sakthivel, Banumathi Arabindoo, M Palanichamy & V Murugesan*

Department of Chemistry, Anna University, Chennai 600 025, India

Received 20 June 2000; accepted 3 January 2001

The photocatalytic degradation of the dye, reactive red 2 has been investigated in aqueous heterogenous solution containing TiO2 as photocatalyst in a batch reactor. The disappearance of the dye follows approximately pseudo-first order kinetics according to the Langmuir-Hinshelwood model. The addition of optimal amount of hydrogen peroxide and potassium persulphate enhances the degradation rate of the dye. The presence of sodium carbonate and sodium chloride hinders the photocatalytic degradation. TiO2 has been experimentally found to be highly efficient photocatalyst in the degradation of textile dyes and hence there is a great potential in the treatment of effluents from textile industries by photocatalytic degradation technique.


Indian Journal of Engineering & Materials Sciences

Vol. 8, April 2001, pp. 110-113

 

Effect of sodium sulphate on the hydration of granulated blast furnace slag blended portland cement

 

Neelam Singh, Sarita Rai & N B Singh*

Department of Chemistry, DDU Gorakhpur University, Gorakhpur 273 009

Received 30 July 1999; accepted 8 March 2001

The effect of 4 wt% Na2SO4 on the hydration of granulated blast furnace slag (GBFS) blended portland cement (1:1, referred to as the blended cement here) has been studied. Na2SO4 accelerates the hydration in addition to activating the granulated blast furnace slag at the same time. Activating action may be explained by breaking of different bonds at the surface of the slag.


Indian Journal of Engineering & Materials Sciences

Vol. 8, April 2001, pp. 114-117

 

Sintering 2000: Conference Report

 

G S Upadhyaya

Department of Materials and Metallurgical Engineering, Indian Institute of Technology, Kanpur 208 016, India

Received 15 November 2000; accepted 5 March 2001

The presentations made during Sintering 2000 (7th International Conference on Sintering), organised under the auspices of the International Institute for the Science of Sintering (IISS), Belgrade, are reviewed here. The conference was divided into 15 Technical Sessions for the invited and contributed papers. The sessions were grouped as: Fundamentals; Advanced Processing Methods; Ferrous Materials; Non-Ferrous/Intermetallic Materials; Oxide Ceramics; Non oxide Ceramics; Cermets; Ceramics Matrix Compounds; and, Electronic Materials.


Indian Journal of Engineering & Materials Sciences

Vol. 8, April 2001, p 118

 

Book Review

 

Material Marvels, by B C Sharma (National Book Trust, India), pages 136, viii, price Rs 40.00

 

 

 

February

April

June

August

October

December