Indian Journal of Engineering & Materials Science


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VOLUME 13
CODEN : IEMSEW

NUMBER 4

AUGUST 2006
ISSN : 0971-4588

 

 

 

CONTENTS

 


Engineering

 

 

A low jitter variable delay generator for regenerative amplifier in a table top terawatt femto second laser system

 

269

        M S Ansari, Bhupinder Singh & C P Navathe

 

        [IPC Code: H01S, H03K 3/00]

 

 

Prediction of tool wear in high speed machining using acoustic emission technique and neural network

 

275

        B Giriraj, V Prabhu Raja, R Gandhinadhan & R Ganeshkumar

 

        [IPC Code: B23Q, G05B 19/18]

 

 

Effect of various stress ratio parameters on cold upset forging of irregular shaped billets using white grease as lubricant

 

281

        K Baskaran & R Narayanasamy

 

        [IPC Code: B21J, B23K 20/00]

 

 

A comparative study of the effect of model lift coefficients on particle trajectory

293

        Pankaj K Gupta & Krishnan V Pagalthivarthi

 

        [IPC Code: F15D]

 

 

Optimization of inlet valve closure timing and clearance volume of a SI engine for better performance at part loads¾A numerical and experimental approach

 

307

        J M Mallikarjuna & V Ganesan

 

        [IPC Code: F01L 1/34]

 

 

Freeway traffic flow control by lumped parameter system approach

322

        Ahmet Akbaş & Murat Ergun

 

        [IPC Code: G08G 1/00]

 

 

Application of ground scrap tyre rubbers in asphalt concrete pavements

333

        F A Aisien, F K Hymore & R O Ebewele

 

        [IPC Code: C08L 95/00, E01C 7/18]

 

 

Materials Science

 

 

Microstructural features, electrical and optical properties of nanostructured InSb thin films deposited at 373 K

 

339

        Sukhvir Singh, A K Srivastava, K Lal, Y Tomokiyo, S K Sharma & R Kishore

 

        [IPC Code: H01C 17/075]

 

Tape casting of alternate electrolyte components for solid oxide fuel cells

347

        A Samson Nesaraj, I Arul Raj & R Pattabiraman

 

        [IPC Code: H01M 8/10]

 

 

Synthesis and characterization of greenish-blue light emitting lithium-boron complex for organic light emitting diode applications

 

357

        Aparna Misra, Pankaj Kumar, Lokendra Kumar, S K Dhawan, M N Kamalasanan & Subhas Chandra

 

        [IPC Code: H01L 51/52]

 

 

Diffusion bonding of fine grained high carbon steels in the super-plasticity temperature range

 

362

        Mustafa Taşkın, Nuri Orhan & Sermin Ozan

 

        [IPC Code: C21C 5/00]

 

 

Overview literature on atomic force microscopy (AFM): Basics and its important applications for polymer characterization

 

368

        R N Jagtap & A H Ambre

 

        [IPC Code: G01N 13/16]

 

 

_______________

 

IPC: International Patent Classification

 

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

 

 

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, August 2006, pp. 269-274

 

 

A low jitter variable delay generator for regenerative amplifier
in a table top terawatt femto second laser system

 

M S Ansari, Bhupinder Singh & C P Navathe

 

This paper describes the design and development of a pulse selector circuit, two different low cost techniques for generation of low jitter variable delays and a high band width line driver for use in the regenerative amplifier stage of a table top Terawatt femto second laser chain. The pulse selector stage selects one pulse from a high frequency laser oscillator, injects it into the regenerative amplifier and ejects it after a preset delay. Two different schemes for the delay generator described here are based on the IC AD 9501 and ECL mono shots. These can provide variable delay in the range of 2.5-800 ns. Jitter in the set delay for the circuit based on ECL mono shot is found to be 800 ps. Whereas, jitter for the circuit based on AD9501 is dependent on the set delay and varies between 500 ps to 2.2 ns over the entire delay range of 2.5-800 ns.

IPC Code: H01S, H03K3/00

 

 

 Indian Journal of Engineering & Materials Sciences

Vol. 13, August 2006, pp. 275-280

 

Prediction of tool wear in high speed machining using acoustic emission technique and neural network

 

B Giriraj, V Prabhu Raja, R Gandhinadhan & R Ganeshkumar

 

High speed machining (HSM) provides a lot of perks like higher productivity, better surface finish and good accuracy but with the limitation of rapid tool wear rate. On-line tool wear monitoring is therefore essential for a fully automated high speed machining process. Acoustic emission (AE) technique has proven to be a better tool wear monitoring method owing to its sensitivity, quick response time and consistency. This work deals with the formulation of methodology and conduct experiments for predicting the tool wear in high speed machining using acoustic emission technique and artificial neural network (ANN). Taguchi’s design of experiments has been used to optimize the number of experiment. The experimental observations are used to train an artificial neural network to predict the progressive tool wear. The outcome of the work includes the selection of optimum cutting parameters for minimum tool wear, identification of the percentage contribution of individual parameters towards tool wear and the prediction of tool wear using artificial neural network with a maximum deviation of 4%.

IPC Code: B23Q, G05B19/18

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, August 2006, pp. 281-292

 

 

Effect of various stress ratio parameters on cold upset forging of irregular shaped billets using white grease as lubricant

 

K Baskaran & R Narayanasamy

 

The aim of this study is to investigate the effect of various stress ratio parameters on cold upset forging of commercially pure aluminium solid billets of irregular shaped billets using white grease as lubricant applied on both sides. Samples with two different aspect ratios (ratio of height to diameter) namely, 0.5, 0.75 and 1.0, with different b/a ratios (ratio of minor to major diameter) namely 0.6 and 0.7 were prepared and cold forged. Cold deformation experiments were carried out in an incremental step and at the end of each step, dimensions such as height, contact and bulged diameters being measured. The calculations were made with the assumption that the radius of curvature of the barrel followed the form of a circular arc. Analysis of the experimental data showed that there exists a relationship between the measured barrel radius and various stress ratio parameters namely, (sq/sz), (sm/sz), (seff/sz), and (sm/seff) developed under plane stress condition. An attempt has also been made to relate the percentage height reduction with respect to the stress ratio parameters namely, (sq/sz), (sm/sz), (seff/sz), and (sm/seff) developed under plane stress condition and found to have an increasing trend with enhanced level of deformation.

IPC Code: B21J13/00, B23K20/00

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, August 2006, pp. 293-306

 

 

A comparative study of the effect of model lift coefficients on particle trajectory

Pankaj K Gupta  & Krishnan V Pagalthivarthi

 

The objective of the present work is to (i) study the influence of different model lift coefficients, (ii) evaluate the importance of particle rotation, and (iii) compare the present computed results with two-way coupling results (in open literature) on the particle trajectory in dilute two-phase gas-solid horizontal channel flow. A hybrid Eulerian-Lagrangian method is employed where the Reynolds averaged Navier-Stokes (RANS) equations with k-e closure are used to model the fluid phase, and the particulate phase is treated via Lagrangian approach. Particle-wall collision is modeled using impulse-momentum equations. Five different models of lift coefficients (and/or lift forces) are selected from the open literature to evaluate the influence of lift force on the particle. The effect of shear lift is relatively very small as compared to lift due to particle rotation. Particle rotational velocities of the order of magnitude as high as 104-105 rad/s are encountered due to particle-wall collision. Results of computed particle trajectories with simplified assumptions agree closely with (i) the simulated results of FLUENT® (Version 6.1) with one-way and two-way coupling, and (ii) of other authors using two-way coupling. In terms of particle lift (and trajectory), the simulated results of FLUENT® with one-way coupling are in agreement with the literature than two-way coupling.

IPC Code: F15D

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, August 2006, pp. 307-321

 

 

Optimization of inlet valve closure timing and clearance volume of a SI engine for better performance at part loads¾A numerical and experimental approach

J M Mallikarjuna & V Ganesan

 

In this paper, a computer simulation and experimental investigations on a single cylinder, four-stroke, spark ignited engine are carried out to optimize inlet valve closure timing and clearance volume for better part-load performance. The simulation procedure involves thermodynamic and global modeling techniques. Many sub-models have been used for predicting heat transfer, friction and gas exchange processes. Unburned hydrocarbons, carbon monoxide and nitric oxide emissions are also predicted.

Experiments have been conducted on a single cylinder, air-cooled, four-stroke, spark-ignited engine. In this work, by varying inlet valve closure timing (IVCT) and clearance volume, geometric expansion ratio (GER) of engine alone is varied, while effective compression ratio (ECR) is kept constant, thereby GER/ECR ratio is altered. For modified engine, GER/ECR ratio is varied from 1.25 to 2. Experiments have been conducted for two effective compression ratios, viz., 7 and 8 at a speed of 1200 rpm. Performance and exhaust emission characteristics have been measured at different loads and GER/ECR ratios. The predicted performance and emission characteristics are compared with measured values and the agreement between the two is found to be good. It is observed that, for modified engine, considerable improvements have been found in the reduction of pumping losses (about 25.8 to 56%), increase in the brake thermal efficiency (about 13.6 to 25%), and reduction in unburned hydrocarbon emissions (about 18.5 to 58%). Finally, for modified engine, it is found that GER/ECR ratio of 1.5 gives the best performance compared to standard engine for both compression ratios.

IPC Code: F01L1/34

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13 August 2006, pp. 322-332

 

 

Freeway traffic flow control by lumped parameter system approach

 

Ahmet Akbaş & Murat Ergun

 

Freeway traffic flows can be controlled by lumped parameter system approach owing to the space discretized system models. Such a control model incorporating a coordinated ramp metering mechanism is proposed in this study. The non-linear state equations representing the traffic system dynamics are derived from the conservation law in difference equations form. The control model is obtained by a feedback linearization approach, so that the target density of the controller is chosen as the critical density of the traffic system. Simulation based test studies have been done in a VISSIM simulation environment in order to compare the data obtained by the shock wave modified feedback linearization method to the non-modified type, with respect to the uncontrolled system performance. Test results show that the main-link flow performance is increased sufficiently by the proposed control model.

IPC Code: G08G1/00

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, August 2006, pp. 333-338

 

Application of ground scrap tyre rubbers in asphalt concrete pavements

F A Aisien, F K Hymore & R O Ebewele

 

A laboratory scale evaluation of the feasibility of using ground rubber from scrap tyres in dry process hot-mix asphalt concrete used for road pavement was investigated. The rubber to asphalt ratio (by weight) of the specimens that was initially kept constant at 0.2 was subsequently varied from 0.1 to 0.5 using different rubber particle sizes. Some specimens were cured at ambient temperature, while others were soaked in water inside a curing tank, for a period of 28-days in the laboratory. The Marshall method was used to prepare both conventional and rubberized asphalt concrete specimens. The indirect tensile testing machine was used in the measurements of mechanical properties of all specimens. The results from the study show that the rubberized asphalt concrete mix has much better mechanical properties than the conventional one: the tensile strength of the specimens for example, increased from 1.82 ´ 103 to 2.04 ´ 103 kPa as the rubber to asphalt ratio increased from 0.1 to 0.3. Similar trends were observed in compressive and tensile moduli. The mechanical properties of rubberized specimens cured in air and those soaked in water were not significantly different (P>0.05). However, the conventional concrete especially those soaked in water showed inferior mechanical properties. The rubber particle size of 0.60 mm had the best mechanical properties while that of particle size 2.36 mm has the poorest mechanical properties.

IPC Code: C08L95/00, E01C7/18

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, August 2006, pp. 339-346

 

Microstructural features, electrical and optical properties of

nanostructured InSb thin films deposited at 373 K

 

Sukhvir Singh, A K Srivastava, K Lal, Y Tomokiyo, S K Sharma & R Kishore

Thin films of InSb nanocrystals have been deposited onto KCl substrate using a thermal evaporation technique under high vacuum conditions (~10-6 torr). An intriguing microstructure consisted of moiré fringes with variable spacings and a corresponding variety of electron diffraction patterns in reciprocal space are reported at the deposition temperature of 373 K. The nanograins of InSb with preferred orientation and faceted morphology are delineated. A possible mechanism has been postulated to explain the evolution of such microstructures. It has been noticed that there is a peculiarity in the resistivity characteristics and infrared transmittance measurements obtained on these films. A set of electron micrographs, diffraction patterns and properties have been evaluated and discussed to understand the role of nanocrystals constituting the thin film, and certain types of defects introduced in the microstructure while deposition, on these properties.

IPC Code: H01C17/075

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, August 2006, pp. 347-356

 

Tape casting of alternate electrolyte components for solid oxide fuel cells

A Samson Nesaraj, I Arul Raj & R Pattabiraman

 

The solid oxide fuel cell (SOFC) consists of four electrochemically active solid components, viz., a porous cathode, a porous anode, a dense electrolyte and a dense interconnect to form stacks. Tape casting technology involves the dispersion of inorganic ceramic particles (electrolyte) in a liquid (solvent) medium followed by the addition of organic binders, plasticizers and deflocculating or defoaming agents to fabricate a thin ceramic sheet. In this research work, the selection and loading level of additives have been optimized to fabricate alternate electrolyte components of SOFC viz. La0.9Sr0.1Ga0.8Mg0.2O3-d, Ce0.90Gd0.10O2-d and Ce0.80Sm0.20O2-d by tape casting technique. In order to remove the organic substances from green electrolyte components and sintering, the heat treatment of green tapes has been optimized by thermogravimetry differential thermal analysis (TG-DTA). The surface morphology of both green and pre-sintered components has been studied by Scanning Electron Microscopy (SEM).

IPC Code: H01M8/10

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2006, pp. 357-361

 

 

Synthesis and characterization of greenish-blue light emitting lithium-boron complex for organic light emitting diode applications

Aparna Misra, Pankaj Kumar, Lokendra Kumar, S K Dhawan, M N Kamalasanan & Subhas Chandra

 

A lithium-boron complex, lithium tetra (2-methyl 8-hydroxy quinolinato) boron (LiBqm4), which emits greenish-blue light has been synthesized by the reaction of LiBH4 with 2-methyl 8-hydroxyquinoline in a molecular weight ratio of 1:4, and used for organic light emitting diodes (OLEDs) fabrication. The complex has been characterized by optical absorption, Fourier Transform Infrared (FTIR), photoluminescence (PL) and electroluminescence (EL) spectroscopic methods. The thermo-gravimetric analysis (TGA) suggests that the material is quite thermally stable up to 380oC. An optical band gap of 3.15 eV using the well-known Tauc relation and an exciton binding energy of 0.69 eV has been evaluated. OLEDs have been fabricated in ITO/N,N′-di-(3-methyl-phenyl)-N,N′diphenyl-4,4′diaminobiphenyl(TPD)/LiBqm4/Al configuration. PL and EL peaks exist at 503 nm. I-V characteristic of device reveals that at higher voltages the current follows I µ Vm law, where m > 1.

IPC Code: H01L 51/50

 

Indian Journal of Engineering & Materials Sciences

Vol. 12, August 2006, pp. 362-367

 

 

Diffusion bonding of fine grained high carbon steels in the super-plasticity temperature range

Mustafa Taşkın, Nuri Orhan & Sermin Ozan

 

In this study, diffusion bonding behaviour of two high carbon hypoeutectoid steels was investigated. The steel specimens were heat treated to induce a fine grain structure and diffusion bonded within a temperature range where these steels exhibit superplasticity. The results showed that these steels could be bonded successfully at 650oC and 735oC within the superplastic temperature range, but poor diffusion bonds were fabricated at a temperature of 850oC. The poor bonding was attributed to an increase in grain size, which not only reduce grain boundary diffusion mechanisms, but also a loss in superplastic deformation behaviour could be expected.

IPC Code: C21C 5/00

Indian Journal of Engineering & Materials Sciences

Vol. 13, August 2006, pp. 368-384

 

 

Overview literature on atomic force microscopy (AFM): Basics and its important applications for polymer characterization

R N Jagtap  & A H Ambre

 

Atomic force microscopy (AFM) is a relatively new technique used for the surface characterization of polymers. It is capable of producing images of a non-conducting polymer surface without any chemical etching or staining. The unique feature of this technique as compared to other microscopy techniques is that we can study the mechanical properties of the polymer surface and it also does not involve the use of electron beam radiation that damages the polymer surface. This paper describes the various applications of atomic force microscopy like evaluation of mechanical properties, determining the chemical composition, studying photo-oxidative degradation of polymers, measuring the surface adhesion forces, studying the thermal phase transitions in polymers and determining the molecular weight and polydispersity index of polymer brushes. These applications have been elucidated with suitable examples.

IPC Code: G01N13/16