Indian Journal of Engineering & Materials Science

 

 

 

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VOLUME 13
CODEN : IEMSEW

NUMBER 1

FEBRUARY 2006
ISSN : 0971-4588

 

CONTENTS

 

Engineering

 

Optimal mix for high performance concrete by evolution strategies combined with neural networks

7

        S Rajasekaran

 

        [IPC Code: C04B14/00, G06N5/00]

 

 

 

Compressive strength and ultrasound pulse velocity of mineral admixtured mortars

18

        Rüstem Gül, Ramazan Demirboğa & Tekin Güvercin

 

        [IPC Code: C04B]

 

 

 

Effect of curing conditions on the engineering properties of self-compacting concrete

25

        Salih Yazicioglu, Sinan Caliskan & Kazim Turk

 

        [IPC Code: C04B14/00]

 

 

 

Perforated plates with a splitter—Unsteady pressure measurements

30

        Subhash C Yaragal

 

        [IPC Code: G01F1/00]

 

 

 

Optimization of friction welding parameters using simulated annealing

37

        P Sathiya, S Aravindan, A Noorul Haq & K Panneerselvam

 

        [IPC Code: B23K20/12]

 

 

 

Effect of die profile on the wrinkling behaviour of three different commercially pure aluminium grades when drawn through conical and tractrix dies

45

        C Loganathan & R Narayanasamy

 

        [IPC Code: C22B21/00]

 

 

 

Investigation of a power FLIMOSFET based on two-dimensional numerical simulations

55

        Rakesh Vaid & Naresh Padha

 

        [IPC Code: H02M]

 

 

 

Materials Science

 

 

 

Equilibrium swelling, conductivity and electroactive characteristics of polyacrylamide hydrogels

62

        Rahna K Shamsudeen, Shiny Nair & V G Jayakumari

 

        [IPC Code: C08F120/00]

 

Influence of titanium ions on dielectric and other physical properties of AF-PbO-B2O3 glasses

69

        P Nageswara Rao, D Krishna Rao & N Veeraiah

 

        [IPC Code: C03C3/21]

 

 

 

Strength and durability of cementitious binder produced from fly ash-lime sludge-Portland cement

75

        Mridul Garg & Manjit Singh

 

        [IPC Code: C04B7/00, B28B]

 

 

 

Synthesis, characterization and thermolysis of polynitrohexahydropyrimidines: Potential high energy materials

80

H S Jadhav, M B Talawar, R Sivabalan, D D Dhavale, S N Asthana &
V N Krishnamurthy

 

        [IPC Code: C06B25/00]

 

 

 

Effect of additives on Al2O3 based LPG sensors

 87

G N Chaudhari, P R Padole, S S Patil, U S Khandekar, V S Sapkal &
S V Manorama

 

        [IPC Code: H01C17/065]

 

 

 

_______________

 

IPC: International Patent Classification

 

Int. Cl.8: International Classification 8th edition, 2005

 


 

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, February 2006, pp.7-17

 

Optimal mix for high performance concrete by evolution strategies
combined with neural networks

 

S Rajasekaran

 

There is a growing interest in the application of non-traditional methods such as simulated annealing (SA) and genetic algorithm (GA) and evolution strategies (ES) for optimization of structural systems. In this paper, evolution strategies (ES) is used to find the optimal mix design for high performance concrete (HPC) comprised of cement, sand, coarse aggregate, water, silica fume and super pasticizer. It is required to get the optimal mix for strength for 120 MPa and slump of 120 mm. In order to get the equation for strength and slump, the sequential learning neural network (SLNN) proposed by Zhang and Morris is used. The cost function to be minimized is the cost of HPC/unit weight of HPC subjected to strength and slump constraints. It is concluded that the method proposed is highly suitable for getting the optimal mix for high performance concrete in practice.

IPC Code: C04B14/00, G06N5/00

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, February 2006, pp. 18-24

 

Compressive strength and ultrasound pulse velocity of mineral
admixtured mortars

Rüstem Gül, Ramazan Demirboğa & Tekin Güvercin

 

Ultrasound pulse velocity is used to evaluate the compressive strength of mortar with mineral admixtures. In addition, the relationship between ultrasound velocity and destructive compressive strength are evaluated. Silica fume (SF), fly ash (FA) and blast furnace slag (BFS) are used as mineral admixtures for the replacement of Portland cement (PC) up to 30%, 50% and 70%, respectively, by weight. The maximum compressive strength and ultrasonic pulse velocity (UPV) have been observed with the samples containing BFS. Both compressive strength and UPV are very low for all the levels of mineral admixture at an early age curing, especially for samples containing high volume FA. However, with the increase of curing period both compressive strength and UPV of all the samples are increased. 10% of SF increased both compressive strength and UPV at 7, 28 and 90-day curing period, but the other SF replacement decreased. At 28 and 90-day of curing periods, BFS increased UPV for all levels and increased compressive strength for 10% and 20% BFS replacement. In addition, reductions due to BFS at early ages are decreased for the other level of BFS, even at 28-day of curing period and for 10%, 20%, 30% and 50% increased compressive strength 36%, 24%, 22% and 8%, respectively. The increment in the compressive strength due to curing period is higher than that of UPV. The relationship between UPV and compressive strength is exponential for SF, FA and BFS.

IPC Code: C04B

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, February 2006, pp. 25-29

 

Effect of curing conditions on the engineering properties of self-compacting concrete

Salih Yazicioglu, Sinan Caliskan & Kazim Turk

 

The paper reports an experimental study investigating the influence of curing conditions on the engineering properties of self-compacting concretes (SCC). Portland cement (PC) concrete and two types of SCC, i.e., SCC-I with fly ash and SCC-II with silica fume, specimens are prepared and cured in three different curing conditions, namely standard 20°C water, sealed and air cured for the periods of 3, 7, 14 and 28 days. At the end of each curing period, compressive and tensile strength and ultrasonic pulse velocity (UPV) values are determined. The results showed that water cured specimens always give the highest values followed by those cured as sealed and in air irrespective of type and age of concrete and test methods. For both compressive and tensile strength tests, the SCC-II gives the highest values followed by SCC-I and then PC concrete for all curing periods and conditions. Whilst, the UPV results showed that the highest values are obtained from the SCC-I and then from the PC concrete and SCC-II for all curing conditions.

IPC Code: C04B14/00

 

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, February 2006, pp. 30-36

 

 

Perforated plates with a splitter—Unsteady pressure measurements

 

Subhash C Yaragal

 

Wind tunnel experiments have been conducted under highly turbulent and disturbed flow conditions over a solid/perforated plate with a long splitter plate in its plane of symmetry. The effect of varied level of perforation of the normal plate on the fluctuating pressures measured across and along the separation bubble has been studied. The distribution of the unsteady surface pressures with variation of the perforation level of the normal plates is also studied. The different perforation levels of the normal plate that is 0%, 10%, 20%, 30%, 40% and 50% are studied. The Reynolds number based on step height is varied from 4´103 to 1.2´104. It is interesting to note that for 50% perforation of the normal plate, the RMS pressure fluctuation in the flow field gets reduced to around 60% as compared to that for solid normal plate. Analysis of the results show that the maximum fluctuating surface pressures as well as the fluctuating pressures in the flow field can be well correlated.

IPC Code: G01F1/00

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, February 2006, pp. 37-44

 

 

Optimization of friction welding parameters using simulated annealing

 

P Sathiya, S Aravindan, A Noorul Haq & K Panneerselvam

 

Friction welding is a solid state bonding technique which utilizes the heat generated by rubbing of two faying surfaces for the coalescence of material. Friction welding process is normally considered as a multi-input and multi-output process. Optimization of friction welding parameters is required to get good quality joints. Present study establishes the relationship between the input variables and output variables. Heating pressure (HP), heating time (HT), upsetting time (UT) and upsetting pressure (UP) are the input variables. The flash features such as flash thickness (FT), flash height (FH) and flash width (FW) are considered as output variables. The relationship between these input and output variables is established through artificial neural network (ANN). ANN is suitably integrated with the optimization algorithm in order to minimize the metal loss without sacrificing the tensile strength of the joints. The variation between theoretical and experimental values of flash features is also analyzed.

IPC Code: B23K20/12

 

 

 

 

 

 

 

 

 

Journal of Engineering & Materials Sciences

Vol. 13, Feb 2006, pp. 45-54

 

 

Effect of die profile on the wrinkling behaviour of three different commercially pure aluminium grades when drawn through conical and tractrix dies

C Loganathan  & R Narayanasamy

 

Experiments have been carried out to evaluate the onset of wrinkling behaviour in three grades of annealed commercially pure aluminium sheets namely ISS 19000, ISS 19600 and ISS 19660 having thickness 2 mm, while drawing them through conical and tractrix dies. The deep drawing of circular blanks of different diameters of the previously mentioned sheet metals has been carried out using flat bottom punch. The analysis of the experimental data has revealed that the onset of wrinkling takes place when the ratio of the plastic strain increments (dεr/dεθ) reached a critical value. It has been also found that the measured strains followed non-linear paths in the wrinkling limit diagrams. Further, it has been observed that the aluminium grade having high strain hardening index value, low yield stress and high normalized hardening rate shows better resistance against wrinkling. Drawing with the tractrix die shows better resistance against wrinkling as compared to drawing with the conical die.

IPC Code: C22B21/00

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, February 2006, pp. 55-61

 

Investigation of a power FLIMOSFET based on two-dimensional
numerical simulations

 

Rakesh Vaid  & Naresh Padha

 

This paper presents the numerical simulation results for a power FLIMOSFET structure with up to eleven vertical floating islands, designed using PISCES-IIB, a 2-dimensional advanced device simulator. The novel structure is based on the FLI-diode concept, which helps in lowering the maximum electrical field in the Nepitaxial region of the device to reduce the effective on–resistance without degrading device performance. Extensive simulations were performed to understand the device physics through various internal electrical quantities like potential distribution and electric field in different regions of the device both in on/off states. The effect of drift region doping on the device performance has been discussed. It is shown that the decrease in the drift region doping tends to decrease the electric field distribution and intermediate potential in this region thereby making its on-resistance lower than the value given by the conventional silicon limit. The device structure does not require any precise control of the boron implantation dose in the P+ floating islands for charge balance as essential in case of super junction (SJ)/COOLMOSTM devices. The process flow mechanism required to fabricate FLIMOSFET structure using multi-epitaxial technology has been discussed, which is less complex and less expansive than the super junction (SJ) devices technology.

IPC Code: H02M

Indian Journal of Engineering & Materials Sciences

Vol. 13, February 2006, pp. 62-68

 

 

Equilibrium swelling, conductivity and electroactive characteristics of polyacrylamide hydrogels

Rahna K Shamsudeen, Shiny Nair & V G Jayakumari

 

Polyelectrolyte hydrogels are currently being studied extensively towards the realization of soft actuators. The conductivity, swelling behaviour and electroactive characteristics of partially hydrolysed polyacrylamide hydrogels, crosslinked to various extents are investigated. Conductivity studies have been made by means of dielectric relaxation spectroscopy both for hydrogels and dry gel powders over a wide range of frequency. The water dependent a.c. conductivity has been found to attain a plateau at higher frequencies whereas the a.c. conductivity of gel powders continued to increase as the frequency increases. The magnitude of the conductivity values is dependent on the extent of swelling for the hydrogels whereas it is dependent on the network structure for the gel powders. The electrical responses of hydrolysed polyacrylamide gels are also investigated and its correlation with hydration properties is also made. The on-off stimulation has been monitored by measuring the angular displacement of the hydrogels. A systematic analysis of the obtained results indicates that the electrical response and the water dependent conductivities of the gels have a direct correlation with the hydration properties.

IPC Code: C08F 120/00

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, February 2006, pp. 69-74

 

Influence of titanium ions on dielectric and other physical properties of
AF-PbO-B2O3 glasses

P Nageswara Rao, D Krishna Rao & N Veeraiah

 

Dielectric properties, viz., dielectric constant, e, loss, tan d, a.c. conductivity, s, in the frequency range 102-106 Hz and in the temperature range 30-300oC and the dielectric breakdown strength in air of AF-PbO-B2O3 (A = Li, Na, K) glasses containing different concentrations of TiO2 (in the range 0-0.6 mol %) have been investigated. Results have been analyzed in the light of different oxidation states of titanium ions in the glass matrix with the aid of data on optical absorption, ESR and IR spectral studies.

IPC Code: C03C3/21

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, February 2006, pp. 75-79

 

 

Strength and durability of cementitious binder produced from fly ash–lime sludge–Portland cement

Mridul Garg & Manjit Singh

 

In this paper, investigations have been undertaken to produce cementitious binders by blending 60-70% fly ash with calcined phosphogypsum, hydrated lime sludge, Portland cement and chemical activator in different proportions. The results show that strength development of binders takes place through formation of ettringite, C-S-H and wollastonite. The durability of cementitious binder has been studied by its performance in water and by accelerated aging, i.e., alternate wetting and drying as well as by heating and cooling cycles at temperatures from 27 to 50oC. The results indicate that the strength of the binder decreased with increasing cyclic studies at different temperatures. The maximum fall in compressive strength has been noted at 50oC.

IPC Code: C04B 7/00, B28B

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, February 2006, pp. 80-86

 

 

Synthesis, characterization and thermolysis of polynitrohexahydropyrimidines: Potential high energy materials

H S Jadhav, M B Talawar, R Sivabalan, D D Dhavale, S N Asthana & V N Krishnamurthy

 

A relatively new entrant to the class of high energy materials, viz., 1,3,5-trinitro-5-methyl-hexahydropyrimidine (MTNP) has been synthesized during this work by nitration of 1,3-di-tert-butyl-5-nitro-5-methyl hexahydropyrimidine with fuming nitric acid. The synthesized molecule (MTNP) has been characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy. TG of the compound showed two-step decomposition in the temperature range of 170-200°C and 205-350°C accompanied with 50 and 25% weight loss, respectively. The sensitivity data of MTNP obtained for the synthesized compound indicates its low vulnerability towards external stimuli (impact height, h50% > 100 cm and friction insensitive up to 36 kg). The velocity of detonation of MTNP has been computed using Linear Output Thermodynamic User-friendly Software for Energetic Systems (LOTUSES) code. The theoretically computed VOD of 7450 m/s is intermediate to that of 2,4,6-trinitrotoluene, TNT (6600 m/s) and 1,3,5-triamino-2,4,6-trinitrobenzene, TATB (7860 m/s) coupled with insensitive nature are attractive features from the point of view of its applications in insensitive munitions. In addition to compound MTNP, synthesis and characterization of some of the promising polynitrohexahydropyrimidines have also been reported.

IPC Code: C06B 25/00

Indian Journal of Engineering & Materials Sciences

Vol. 13, February 2006, pp. 87-90

 

 

Effect of additives on Al2O3 based LPG sensors

G N Chaudhari, P R Padole, S S Patil, U S Khandekar, V S Sapkal  & S V Manorama

 

Sensitivity and selectivity of Al2O3 thick films for LPG gas sensor have been examined. The structural properties of Al2O3 have been examined by means of XRD and the surface morphology by the SEM studies. XRD confirmed the complete phase formation at 800oC for 6 h. The sensing properties and response time of (1 wt%) Pd:(10 wt%) Cr2O3 doped Al2O3 have been characterized by d.c. electrical measurements for different gases. The element is exposed to several gases such as LPG, CO, CH4  in dry air. It shows good sensitivity and selectivity towards LPG at low operating temperature.

IPC Code: H01C17/065