023775   Singh K;Pandey S (Mechanical Engineering Dep, SLIET, Longowal, Punjab) : Utilization of slag as a useful flux in submerged arc welding. Indian Weld J 2007, 40(3), 31-8.

Slag generated during submerged arc welding is normally thrown away as a waste. This poses the problem of storage, disposal, environmental pollution and needs landfill space apart from exhaust of non-renewable resources. Reusing of slag will not only solve these problems but also be economical. In the present work an attempt has been made to recycle the submerged arc welding slag as a useful flux in the same submerged arc process. Fused slag was processed by replenishing it with suitable alloying elements/deoxidizers, and by agglomeration. This replenished slag is referred to as recycled slag. Recycled slag in combination with EL-8 filler wire was used for welding. The properties of weld metal deposited with recycled slag were evaluated. The mechanical properties were satisfactory and fulfill AWS (American Welding Society) requirements. The chemical composition of weld metal was within the acceptance range of AWS. The test plates cleared the radiographic test. Cost analysis indicates that it is economically viable to use the recycled slag.

8 illus, 3 tables, 18 ref

023774   Shedge M T;Patel C H;Tadkod S K;Murthy G D (NO, High Energy Materials Research Laboratotry, Pune-411 021) : Polyvinyl acetate resin as a binder effecting mechanical and combustion properties of combustible cartridge case formulations. Def Sci J 2008, 58(3), 390-7.

Several combustible cartridge case (CCC) formulations containing nitrocellulose (NC) as an energetic ingredient with diphenylamine (DPA) as stabiliser, cellulose fiber as reinforcing material and polyvinyl acetate (PVAc) as a binder are processed to form combustible discs. A formulation containing nitrocellulose (83 parts), cellulose (17 parts), PVAc (20 parts) and diphenylamine (1 part) by weight was observed with the improvement of mechanical properties without any adverse effect on combustion characteristics, safety parameters and compatibility with triple base multi-tubular propellant. Dynamic firing performance was also satisfactory.

6 illus, 7 tables, 19 ref

023773   Sharma A;Arora N;Mishra B K (NO, Institute of Petroleum Technology, Gandhinagar) : Modified mathematical models for melting rate in submerged arc welding. Indian Weld J 2007, 40(4), 21-32.

Simulated annealing has been used to calibrate the proposed models and subsequently the models are validated with data points different from the points used for model calibration. The modified models provide better accuracy than the models that have been constituted with the above stated assumption as well as it is more practical than those models in which actual electrode extension has been experimentally measured. The outcome of investigation has been analyzed in terms of improvement in the predictability, resemblance with physics of the process and generalization capacity of the models. The approach of the present work is applicable for future research in other welding processes.

6 illus, 1 table, 19 ref

023772   Senthil Kumar K;Sudhir Reddy C;Shanmugan J (Madras Institute of Technology (MIT), Anna Univ, Chennai-600 044) : Design and simulation of blending function for landing phase of a UAV. Def Sci J 2008, 58(3), 315-26.

This paper aims to achieve the autonomous landing of unmanned air vehicle (UAV). It mainly deals with glide path design, flare path design, design of blending function, and interfacing the glide and flare paths with the blending function. During transition from glide slope to flare path, a UAV will tend to the unstable region. In a manned aircraft, the pilot controls the unstability that occurs during the change of phase from glide slope to flare, but which is impossible in UAV till now. A blending function has been formulated for use in a UAV to overcome this unstability during transition. This simulation is done with the Matlab Simulink and the results are reported.

30 lllus, 3 tables, 13 ref

023771   Sengupta S (NO, Sharada Welding (P) Ltd, ) : Present international trend in use of techno-economic products, "tubular hardfacing electrodes" for wear-resistance. Indian Weld J 2007, 40(1), 29-34.

Describes in brief the Hard Surfacing Processes and Consumables with more emphasis and details on "Tubular Stick Electrodes" which are now considered as more Techno-Economic Products for Hardfacing of components against Wear in preference to "Conventional Solid-Core Stick Electrodes". The present International trend in using THF electrodes is gaining more popularity for techno-economic advantages associated with such Products. The construction of "Tubular Hardfacing Stick Electrodes" including its salient features, advantages, economics & also the manufacturing process have been described in this article.

1 illus, 4 ref

023770   Rohini B;Sreekantha Reddy J (NO, Combat Vehicle Research and Development Establishment, Chennai-600 054) : Sensors in ummanned robotic vehicle. Def Sci J 2008, 58(3), 409-13.

Unmanned tracked vehicles are developed for deployment in dangerous zones that are not safe for human existence. These vehicles are to be fitted with various sensors for safe manoeuvre. Wide range of sensors for vehicle control, vision, and navigation are employed. The main purpose of the sensors is to infer the intended parameter precisely for further utilisation. Software is inseparable part of the sensors and plays major role in scaling, noise reduction, and fusion. Sensor fusion is normally adapted to enhance the decision-making. Vehicle location and orientation can be sensed through global positioning system, accelerometer, gyroscope, and compass. The unmanned vehicle can be navigated with the help of CCD camera, radar, lidar, ultrasonic sensor, piezoelectric sensor, microphone, etc. Proximity sensors like capacitive and RF proximity detectors can detect obstacles in close vicinity. This paper presents an overview of sensors normally deployed in unmanned tracked vehicles.

1 illus, 6 ref

023769   Raja Singh Tangadurai G;Subhash Chandran B S; Babu V;Sundararajan T (Defence Research & Development Laboratory, , Hyderabad-500 058) : Numerical analysis of integrated liquid Ramjet engine. Def Sci J 2008, 58(3), 327-37.

The numerical simulation of an integrated, liquid-fuelled ramjet engine comprising supersonic air intake, subsonic combustor and a convergent-divergent nozzle has been carried out and the results are discussed in this paper. These results include cold flow studies, heat addition in the combustor and full engine analysis with coupled simulation of supersonic air-intake and combustion chamber along with the nozzle. Overall ramjet operation depends on the performance of the air intake and the combustion chamber. The coupling phenomena are very dominant and performance of air intake is affected vastly by the combustor operation and vice versa. In this paper, a numerical analysis of integrated liquid ramjet engine considering coupling phenomena between various sub-systems viz., air intake, combustor and nozzle has been reported.

24 illus, 11 ref

023768   Raha D (NO, Wollongong Univ, Northfields Avenue, New South Wales, 2522, Australia, Email: debashis_raha@yahoo.com.au) : Exploring artificial neural networks (ANN) modelling for a biological nutrient removal (BNR) sewage treatment plant (STP) to forecast effluent suspended solids. Indian chem Engr 2007, 49(3), 205-20.

For a large percentage of the world's population, water crisis' is both a symptom and a cause of poverty, which lies at the heart of human survival and that of the Earth. Although water is the most widely occurring substance on our planet, only 0.65% of it is available as freshwater. In the 20* century, while population increased almost three-fold, water withdrawals increased seven-fold and this trend is continuing. Water is a finite and vulnerable resource, essential for sustaining life, economic development and the environment. To meet the increasing demand for freshwater, water conservation, demand management and beneficial recycling and reuse of effluent from sewage treatment plants (STPs) are the most promising options. In recent times, stringent effluent quality requirements for recycling and reuse have led to a paradigm shift in sewage treatment, focussing heavily on computer model based process control and operational optimisation. In this paper, artificial neural networks (ANN) models have been developed to forecast effluent total suspended solids (TSS) concentration, two to three days in advance for a biological nutrient removal (BNR) STP. This model is expected to assist plant operators to take suitable proactive action to enable the STP to improve its effluent TSS concentration in compliance with regulations and to meet its recycling and reuse quality requirements.

6 illus, 2 tables, 53 ref

023767   Pathak K K;Patil P D;Kalinadh A R;Jain K C (NO, Advanced Materials and Processes Research Institute, CSIR, Bhopal-462 026) : Comparison of mesh adaptivity schemes in finite element simulation of tube extrusion process. Def Sci J 2008, 58(3), 415-21.

Finite element simulation of tube extrusion process has been carried out considering different mesh adaptivity schemes. A comparison of these schemes has been made based on stress, strain distribution, and load-stroke curves. Based on the finite element results, it is observed that the success of the computer simulation is dependent on the mesh refinement criteria.

7 illus, 2 tables, 10 ref

023766   Pal T K (Welding Technology Centre, Metallurgical & Material Engineering Dep, Jadavpur Univ, Kolkata) : Science & technology of welding - A journey towards the 21st century. Indian Weld J 2007, 40(1), 19-28.

Deals with science and technology of several specific areas of welding that have advanced sufficiently in recent years and highlighting the futuristic path of development.

9 illus, 2 tables, 32 ref

023765   Naidu V P S;Raol J R (National Aerospace Laboratories, , banglore-160 017) : Pixel-level image fusion using wavelets and principal component analysis. Def Sci J 2008, 58(3), 338-52.

Image registration and fusion are of great importance in defence and civilian sectors, e.g., recognising a ground/air force vehicle and medical imaging. Pixel-level image fusion using wavelets and principal component analysis has been implemented and demonstrated in PC MATLAB. Different performance metrics with and without reference image are implemented to evaluate the performance of image fusion algorithms. As expected, the simple averaging fusion algorithm shows degraded performance. The ringing tone presented in the fused image can be avoided using wavelets with shift invariant property. It has been concluded that image fusion using wavelets with higher level of decomposition showed better performance in some metrics and in other metrics, principal components analysis showed better performance.

8 illus, 5 tables, 16 ref

023764   Majumdar J;Vanathy B;Lekshmi S (Aeronautical Development Establishment, , Banglore-560 093) : Terrain classification using multiple image features. Def Sci J 2008, 58(3), 353-62.

A wide variety of image processing applications require segmentation and classification of images. The problem becomes complex when the images are obtained in an uncontrolled environment with a non-uniform illumination. The selection of suitable features is a critical part of an image segmentation and classification process, where the basic objective is to identify the image regions that are homogeneous but dissimilar to all spatially adjacent regions. This paper proposes an automatic method for the classification of a terrain using image features such as intensity, texture, and edge. The texlural features are calculated using statistics of geometrical attributes of connected regions in a sequence of binary images obtained from a texture image. A pixel-wise image segmentation scheme using a multi-resolution pyramid is used to correct the segmentation process so as to get homogeneous image regions. Localisation of texture boundaries is done using a refined-edge map obtained by convolution, thinning, thresholding, and linking. The individual regions are classified using a database generated from the features extracted from known samples of the actual terrain. The algorithm is used to classify airborne images of a terrain obtained from the sensor mounted on an aerial reconnaissance platform and the results are presented.

14 illus, 16 tables

023763   Kannan T;Murugan N (Mech Engng Dep, Kumaraguru College of Tech, Coimbatore) : Effect of welding process parameters on microstructures of duplex stainless steel clad metals deposited by FCAW. Indian Weld J 2007, 40(4), 17-20.

Weld cladding is a process of depositing a thick layer of a metal surface to a carbon steel base metal for the purpose of providing a corrosion-resistant surface when that surface is to be exposed to a corrosive environment. In order to maintain the required corrosion resistance and mechanical properties of the claddings, controlling the microstructure is essential. This paper focuses on an experimental study of duplex stainless steel cladding of low carbon structural steel deposited by flux cored arc welding process. Colour metallographic technique was used to study the microstructure of the clad layer cladded under two different heat input conditions with the help of optical microscope.

6 illus, 1 table, 13 ref

023762   Jeyalakshmi S R;Senthil Kumar S;Mathiyarasu J;Phani K L N;Yegnaraman V (Electrodics and Electrocatalysis Div, Central Electrochemical Research Institute, Karaikudi-630 006, Email: al_mathi@yahoo.com) : Simultaneous determination of ascorbic acid dopamine and acid using PEDOT polymer modified electrodes. Indian J Chem-Sect A 2007, 46(6), 957-61.

Dopamine, uric acid and ascorbic acid have been determined simultaneously on a poly(3,4-ethylenedioxylhiophene) modified electrode using electrochemical techniques. On a bare glassy carbon electrode, all three undergo oxidation and appear as a single peak at around 200 mV, whereas on the modified electrode, distinct peaks with clear potential separation are observed, paving way for their simultaneous determination. Detection limits of 7.4 μM, 1.2 μM and 1.4 μM for ascorbic acid, dopamine and uric acid, respectively are observed by pulse voltammetry. The possible interference from creatinine, norepinephrine, epinephrine, glucose, ascorbic acid, urea, oxalate and acetyisalicylic acid (aspirin) has been tested. The protocol developed using this modified glassy carbon electrode has been evaluated using the human blood serum samples for the simultaneous determination of dopamine and uric acid.

4 illus, 3 tables, 19 ref

023761   Jauhari M K;Prasad N V;Rao A T;Premchander V; Nagaraju J S (Welding Technology, Bharat, Earth Movers Ltd (BEML)) : Innovative cost effective concept in GMAW process to improve / enhance weld aesthetics, quality and fatigue life. Indian Weld J 2007, 40(1), 40-5.

4 illus, 5 tables, 6 ref

023760   Hussain M;Sikdar S (NO, , Recl. Shop AGM, Bhilai Steel Plant) : Reclamation of inner telescopic tube-vacuum arc degassing unit of continuous casting unit. Indian Weld J 2007, 40(1), 35-9.

4 illus, 6 tables, 6 ref

023759   Ghosh P K;Kulkarni S;Singh P K;Vaze K K (Metallurgical Dep & Materials Engineering., , Indian Institute of Technology Roorkee) : Superiority of narrow gap SMA welding of 304 in stainless steel pipe. Indian Weld J 2007, 40(4), 44-57.

Shielded metal arc (SMA) welding of 25mm thick wall 325mm O.D, 304LN austenitic stainless steel pipe has been carried out with GTAW root pass by using conventional V-groove and narrow groove welding techniques at appropriately designed WPS to produce sound weld of significantly narrow weld groove. The characteristics of the narrow groove weld joints with respect to their weld size, microstructure, residual stresses, mechanical properties and corrosion susceptibility have been studied and compared to those of the conventional V-groove weld joints. It is observed that the use of narrow groove instead of conventional V-groove in welding of thick wall stainless steel pipe is beneficial especially with respect to reduction in grain coarsening at HAZ adjacent to the fusion line and lowering of residual stresses of weld joint by keeping the mechanical properties and susceptibility to IGC comparable to those of the V-groove weld joint. However the inclusion content of the narrow groove SMA weld has been found comparatively higher than that of the conventional V-groove weld.

9 illus, 11 tables, 15 ref

023758   Ghosh A;Mukherjee S;Chattopadhyaya S;Sarkar P K (M.E. Dept., Kalyani Govt Engg. College, Kalyani) : Weldbead parametric estimation of SAW process through neural network. Indian Weld J 2007, 40(4), 33-43.

An attempt has been made to develop a model to predict the yield characteristics (weld bead parameters) of Submerged Arc Welding (SAW) process with the help of neural network technique. The SAW process has been chosen for this application because of the complex set of variables and high set up cost involved in the process as well as its significant application in the manufacturing of critical equipments which have a lot of economic and social implications. Under this study the neural network model has been trained according to the actual inputs and outputs. After completing training, the desired inputs have been given to the model and it gives the estimated output value. And according to this we can also estimate the error between the actual and predicted results. Neural network is implemented here because of having remarkable ability to derive meaning from complicated or imprecise data and can be used to extract patterns and detect trends that are too complex to be noticed by either humans or other computer techniques. Hence a trained neural network can be thought of as an "expert" in the category of information it has been given to analyses.

13 illus, 6 tables, 30 ref

023757   Dutta G G;Singhal A;Kaushari A;Ghosh A K (NO, Indian Institute of technology, Kanpur-208 016) : Estimation of drug coefficient from radar-tracked flight data of a cargo shell. Def Sci J 2008, 58(3), 377-89.

Two schemes to extract drag coefficient (C_D) by processing the radar-tracked trajectories of artillery shell in motion, have been proposed. Flight trajectories of artillery shell are considered. The proposed schemes are applied on the radar-tracked trajectory data of artillery shell to estimate the C_D.. The C_D is strong function of Mach number. To capture the functional relationship between the C_Dand the Mach number, the C_D of the ammunition was assumed to be a polynomial function of Mach number (separately for subsonic and supersonic). The coefficients of the assumed polynomial were estimated by minimising the error between measured and estimated trajectories. In the second scheme, whole trajectory was split into different sets containing 50 or 100 data points. Each data set was processed using the proposed schemes to estimate numerical values of C_D corresponding to the average Mach number of the chosen data set. The estimated values of the C_D (at different Mach numbers) have been presented along with its standard deviations. The difficulties encountered in processing the real trajectory data using the proposed schemes are also highlighted. It is observed that the proposed schemes could advantageously be applied to quickly estimate the numerical values of the C_D at corresponding Mach numbers, by processing the trajectory data of an artillery shell in motion.

7 illus, 2 tables, 15 ref

023756   Deb A;Raguraman M;Gupta N K;Madhu V (NO, Indian Institute of Science, Banglore-560 012) : Numerical simulation of projectile impact on mild steel armour paltes using LS-DYNA: part 1: validation. Def Sci J 2008, 58(3), 422-32.

The paper describes the simulation of impact of jacketed projectiles on steel armour plates using explicit finite element analysis as implemented in LS-D YNA. Validation of numerical modelling includes a comprehensive mesh convergence study leading to insights not previously reported in literature, using shell, solid, and axisymmetric elements for representing target plates. It is shown for a number of cases that with a proper choice of contact algorithm, element size, and strain rate-dependent material properties, computed projectile residual velocities can match closely with corresponding test-based values. The modelling requirements are arrived at by correlating against published test residual velocities for variants of mild steel plates (designated as MS 1, MS2 and MS3) of different thicknesses at impact velocities in the range of ~820-870 m/s. Using the validated numerical procedure, a number of parametric studies such as the effect of projectile shape and geometric aspect ratios as well as plate thickness on residual velocity have been carried out and presented.

10 illus, 4 tables, 22 ref

023755   Datta S;Bandyopadhyay A;Nandi G;Pal P K;Roy S C (Mechanical Engineering Dep, B.P. Poddar Institute of Management & Technology, 137, V.I.P Road, Kolkata-700 052, Email: s_bppimt@yahoo.com ) : Evaluation of optimal parametric combination in submerged arc double pass butt welding. Indian Weld J 2007, 40(1), 46-52.

Application of Taguchi method with grey relational analysis has been highlighted for solving multiple response optimization problem in submerged arc welding (SAW). A grey relational grade evaluated from the grey relational analysis has been adopted to reveal an optimal parameter combination in order to obtain acceptable features of weld quality characteristics in submerged arc butt welding.

8 tables, 15 ref

023754   Biju K;Narayan Prabhu K;Rajendra Udupa K (Metallurgical Dep & Materials Engineering, National Institute of Technology, Surathkal, Mangalore) : Heat flow simulation and evolution of microstructure in welding of rail steel. Indian Weld J 2007, 40(3), 21-7.

Heat flow simulation was carried out to predict the microstructure and examine the effect of preheat and plate thickness on cooling rate of the weld metal. SOLIDCAST software is used for simulating thermal regime in the base metal. The results of simulation studies revealed that cooling rate and hence the evolution of microstructure along the parent metal were functions of the preheating temperature and the plate thickness. The superimposed simulated temperatures on CCT diagram indicated the absence of martensite precipitation in HAZ region and this was experimentally verified. The results also indicated the possibility of suggesting the preheating temperature for defect-free welding of plates of given thickness.

11 illus, 9 ref

023753   Bhuvaneswari G;Srinivas Rao P;Thakurta S G; Murthy S S (NO, Indian Institute of Technology Delhi, New Delhi-110 016) : Impact of dwell angle on the electromagnetic torque ripples of the switched reluctance motor. Def Sci J 2008, 58(3), 363-71.

Switched reluctance motors (SRM) are emerging as promising competitors to the vector-controlled induction motor (VCIM) drives and permanent magnet (PM) motor drives in the variable-speed drive market owing to their robust nature coupled with low cost, simplicity, and capability to operate in harsh environments. They are also suitable for nuclear and aerospace applications due to their low inertia and capability to be fed from a dc supply through a simple power converter. The principle of torque production in SRM makes rotor position information mandatory for effective control of the drive. The torque produced by any particular phase of the SRM is dependent upon the exciting current and the period during which the current is carried by that phase winding. The conduction period of any particular phase is termed as dwell angle when it is specified in terms of rotor angular position. In the present work, the SRM operation has been analysed in sensor mode and in sensor-less mode, paying special attention to the relationship between dwell angle and output torque ripple. The performance has been studied for different values of dwell angle and the resultant torque profile has been analysed. From the analysis, a methodology has been devised to deduce an appropriate value of dwell angle for minimising the torque pulsations, given the values of speed and load torque, thus improving the performance of the SRM drive.

12 illus, 1 table, 7 ref

023752   Balasubramanian K;Ravi M (Visakhapatnam Steel plant Dy. Manager, , Visakhapatnam Steel plant) : Case study of welding related failures and repair of the reactor of warm argon unit in air separation plant -VSP. Indian Weld J 2007, 40(3), 17-20.

4 illus, 3 ref

023751   Badheka V J;Agrawal S K;Parikh U (Metallurgical Engineering Dep, The M.S. Univ of Baroda, ) : Comparative study of hot cracking susceptibility of AISI 347 austenitic stainless steel (ASS) using acidic and basic coated filler material. Indian Weld J 2007, 40(3), 39-44.

An attempt has been made to study hot cracking susceptibility of stabilized ASS on transvarestraint test unit, with acidic and basic coated electrodes. Experiment, shows that acidic and basic coated electrodes both are more or less equally susceptible to hot.

6 illus, 5 tables, 3 ref

022845   Yazici M (Vocational School of Technical Science, Uludag Univ, 16059, Bursa, Turkey, Email: myazici@uludag.edu.tr ) : Elasto-palstic analysis of stress around square hole. Indian J Engng Mater Sci 2007, 14(3), 215-19.

An elasto-plaslic theoretical analysis of stresses around a square perforated isotropic plate is studied. The boundary of the plastic stress field around the conformally mapped square holes is obtained by using Savin's complex elastic equations. ANSYSr Finite Element Code is used to find out numerical solutions. The elaslo-plastic theoretical and FE solutions arc compared for isotropic plates, with rounded corner square openings. Both solution results are in good agreement with each other.

7 illus, 20 ref

022844   Venkataramana M;Vasudeva Rao V;Ramgopal Varma R;Sunderrajan S (Mechanical Engineering Dep, Sreenidhi Institute of Science and Technology, Hyderabad-501 301) : Instrumentation to measure heat transfer coefficient at the metal mold interface. J Instrum Soc India 2007, 37(3), 157-63.

In the modern technological era where quality is the utmost concern, one can appreciate the application of a precision instrumentation system, with advanced electronic gadgets of high accuracy, for improving the quality and capability of a manufacturing process. Present work deals with the development of precision instrumentation system that captures entire thermal history of the metal casting process. This in turn aids accurate estimation of Metal Mold Interface Heat Transfer coefficient (MMHTC) between a good conducting metal and insulating sand mold. The experimental data thus generated forms a valuable input to the casting simulation software. The experimental runs that are taken with the developed instrumentation system in the present investigation for an aluminium alloy in a green sand mould are found to be consistent and in conformity to the published literature. The capability of the developed system is demonstrated by casting aluminum A-356 alloy in a Green sand mold.

4 illus, 1 table, 4 ref

022843   Usha Singh (Geography Dep, MMV, BHU, Varanasi, Uttar Pradesh) : Study of drainage characteristics of Punpun river basin-a tributary of the Ganga river. Trans Inst Indian Geogr 2007, 29(2), 170-7.

Punpun river basin presents some unique drainage characteristics which the study tries to analyse using quantitative methods. After describing the overall particularity of this drainage basin between the Son in the west and the Phalgu river in the east, the study looks at the drainage network of the tributaries. Some anomalies in the course of the Morar are discussed. It then examines both the drainage frequency and the drainage density which both show regional differences form south to north. Further describes the drainage pattern observed within the Punpun basin.

3 illus, 12 ref

022842   Unnikrishnan P (NO, , Vaidyaratnam Road, Nayadippara, Kottakkal-676 503) : Excerpts from cikitsamanjari - LVI. Aryavaidyan 2008, 21(2), 121-7.

Complications of abortion like upavistaka, nagodara, etc. and their treatments are explained. In case of threatened abortion, the medicines which are to be taken in each month up to 7 months are also explained.

022841   Turkel S;Felekoglu B;Dulluc S (Civil Engineering Dep, Dokuz Eylul Univ, 35160, Izmir, Turkey, Email: selcuk.turkel@deu.edu.tr) : Influence of various acids on the physico-mechanical properties of pozzolanic cement mortars. Sadhana 2007, 32(6), 683-91.

The goal of the study was to compare the acid resistance of a pozzolanic cement (CEM IV-A/32.5) with Portland cement (CEM I 32-5) that was made from the same clinker. For this purpose, 50 mm mortar cubes were prepared with two different kinds of cement according to TS EN 196-1. After 28 days of hardening, the samples were immersed into four different concentrations of hydrochloric, nitric and sulfuric acid solutions for a period of 120 days. The changes in weight loss and compressive strength values for each acid solution within the test period were recorded. The acid resistance of mortars made from Portland cement was better than the pozzolanic cement incorporated samples after 120 days of acid attack.

5 illus, 3 tables, 20 ref

022840   Turk K;Caliskan S;Yazicioglu S (Civil Engineering Dep, Engineering Faculty, Firat Univ, Elazig, Turkey, Email: kturk@firat.edu.tr) : Capillary water absorption of self-compacting concrete under different curing conditions. Indian J Engng Mater Sci 2007, 14(5), 365-72.

Experimental study carried out to investigate the influence of addition of pozzolanic materials and curing regimes on the mechanical properties and the capillary water absorption (sorptivity) characteristics of self-compacting concrete (SCC). Portland cement (PC) concrete and two types of SCO, SCC-I with fly ash (30% FA/70% PC) and SCC-I1 with silica fume (10% SF/90% PC), specimens were prepared and cured in three different curing conditions (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 strengths and ultrasonic pulse velocity (UPV) values were determined; sorptivity coefficents were determined at 28 days. The results indicated that SCC-II specimens gave higher compressive and tensile strength and lower sorptivity coefficient values than those of corresponding SCC-I and PC concrete specimens, regardless of curing regimes and age of concrete. The results also showed a good correlation between the strength development of concrete and its sorptivity, i.e., as the compressive and tensile strengths increased due to the hydration, the sorptivity coefficients decreased significantly.

9 illus, 3 tables, 18 ref

022839   Tangsrirat W (Faculty of Engineering and Research Center for Communications and Info, King Mongkut's Institute of Technology Ladkrabang (KMITL), Chalongkrung Rd., Ladkrabang, Bankok 10520, Thailand, Email: ktworapo@kmitl.ac.th) : Current differencing transconductance amplifer-based currrent-mode four-phase quardrature oscillator. Indian J Engng Mater Sci 2007, 14(4), 289-94.

A realization of a current-controlled current-mode four-phase quadrature oscillator based on current differencing transconductance amplifiers (CDTAs) is proposed. The proposed oscillator circuit employs only three CDTAs and two grounded capacitors, which can provide four high output impedance sinusoidal current outputs with four-phase difference. The oscillation condition and oscillation frequency can be controlled electronically and independently by the transconductance gain of the CDTA. PSPICE simulation and experimental results with the commercially available ICs arc given to confirm the operation of the proposed oscillator.

7 illus, 15 ref

022838   Sudhakar A V;Mohan Rao K;Ramachandra Raju V (Production Engineering Dep, V.R. Siddhartha Engineering College, Vijayawada-520 007, Email: amerinenivs@yahoo.com) : Thermoelastic analysis of a laminated composite skew plate with a circular cutout subjected to linearly varying temperature across the thickness. Indian J Engng Mater Sci 2007, 14(2), 95-102.

The behaviour of a laminated composite skew plate with hole subjected to temperature as well as combined temperature and transverse pressure loading has been investigated. A finite element method which works on the basis of three-dimensional theory of elasticity is employed to evaluate the transverse deflection, in-plane stresses and interlaminar stresses. The results obtained by varying the skew angle and the hole diameter are discussed. It has been observed that the magnitude of the stresses and deflection in case of combined loading is more when compared with the respective values in case of pure thermal loading. The magnitudes of the transverse deflection and in-plane stresses for combined loading are observed to be less at higher skew angles, because the distance between opposite sides of the plate decreases with increase in skew angle causing for increase in the stiffness of the plate. The solutions of skew structures considered in the present analysis will be useful for the construction of safe and efficient structures like skew bridges and swept wings of aircraft structures.

9 illus, 1 table, 10 ref

022837   Subramanian P (Gandhigram Rural Institute-Deemed Univ, , Gandhigram-624 302) : Magnified vernier calipers coincidence model. J Instrum Soc India 2007, 37(3), 164-8.

50 times magnified Vernier Calipers model is constructed. This will facilitate the observer to easily and precisely identify and locate the Vernier coincidence division in a length measurement.

3 illus, 1 table

022836   Sil A;Verma P K (Metallurgical & Materials Engineering Dep, Indian Institute of Technology, Roorkey-247 667, Email: asilfmt@iitr.ernet.in) : Synthesis of nanosized AIN powder using novel nitridation route. Indian J Engng Mater Sci 2007, 14(4), 309-12.

Nanonsized A1N powders were prepared by nitridation of coarse aluminium powder in flowing N₂ and NH₃ gases, using NH₄C1 and KC1 as additives. XRD analysis indicated lhat the pure phase of AIN powder could be obtained by nitridation at 1000°C for 4 h with NH₃ gas. The average particle size of the AIN powder estimated from the XRD pattern is about 29 nm. FE-SEM micrograph revealed the spherical morphology of the powder particles whose sizes are in the range of 26-43 nm.

5 illus, 12 ref

022835   Sengwa R J;Sankhla S (Dielectric Research Lab, Physics Dep, J N V Univ, Jodhpur-342 005, Email: rjsengwa@rediffmail.com) : Low-frequency dielectric response and chain dynamics study of poly (vinyl pyrrolidone)-poly (ethylene glycol) coexisting two-phase polymeric blends. Indian J Engng Mater Sci 2007, 14(4), 317-23.

The dielectric response of various concentration poly(vinyl pyrrolidone)-poly(ethylene glycol) (PVP-PEG) blends with change in polymer chain-length and their different volume mixtures over the entire concentration range were investigated in the frequency range 20 Hz-1 MHz at 25°C. The complex dielectric constant π*(ω), complex electric modulus M*(ω), complex impedance Z* (ω), and a.c. conductivity data were used for the confirmation of the electrode polarization effect, ionic conduction and the micro-Brownian motion of the PVP chain (m-process) in the PVP-PEG blends. All the blends show the dielectric dispersion corresponding to the PVP segmental motion in the upper experimental frequency range whereas in the lower frequency side of the spectra has dielectric dispersion is due to ionic conduction and electrode polarization. The different volume mixtures of some of the different chain-length PVP-PEG blends also shows the polymer chain-length and concentration dependence m-process. All the blends show the d.c. conductivity behaviour in the lower frequency region, which is little affected by the blends composition. The appearance of two separate arcs in the complex impedance plane plots confirms the contribution of nickel-plated cobal electrodes polarization effect to the values of complex dielectric constant of the PVP-PEG blends in the lower frequency range up to 500 Hz.

7 illus, 24 ref

022834   Sen F;Pekbey Y;Sayman O (Mechanical Engineering Dep, Dokuz Eylul Univ, 35100, Bornova, Izmir, Turkey, Email: faruk.sen@deu.edu.tr) : Elastic-plastic stress analysis of a thermoplastic composite disc under parabolic temperature distribution. Indian J Engng Mater Sci 2007, 14(4), 282-8.

In this study, an elastic-plastic thermal stress analysis was carried out on a steel fiber reinforced thermoplastn composite disc under a parabolic temperature distribution. The thermal elastic and elastic-plastic solutions were obtained both analytically and numerically. Therefore, FORTRAN and ANSYS programs were used to calculate of thermal stresses for comparison. Tsai-Hill theory was used as a yield criterion during the solution. Thermal stresses occurred in the disc for the parabolic temperature distribution due to the different thermal expansions in radial and tangential directions. I he magnitudes of the radial stress components were obtained to be small in comparison with the tangential stress components. Additionally, the tangential stress component was found to be compressive and the highest around the inner surface. According to obtained results these two solutions to be in good agreement. The intensities of the residual stress component of the tangential stress and plastic flow were the highest at the inner surface.

11 illus, 2 tables, 15 ref

022833   Sehik Uduman P S;Sulaiman A (Mathematics Dep, B.S.A. Crescent Engineering College, Chennai-48) : Stochastic model for reserve inventory between two machines in series. Pure appl Math Sci 2008, 67(1-2), 99-105.

Optimal reserve inventory between two machines in series is attempted. The output of the first machine M₁ is the input for the second machine M₂. The machine M₂ is forced to be in idle state due to the breakdown or repair of the machine M₁ and idle time cost of M₂ is very high. The ageing of the machine M₁ imposes some changes in its repair time as well as interarrival times between breakdowns. So using the so called Setting Clock Back to Zero (SCBZ) property for the two random variables namely the repair time and interarrival times between breakdowns of M₁ the optimal reserve inventory size is obtained. Numerical illustration also furnished.

4 ref

022832   Sarawat K C;Kim D;Krishnamohan T;Pethe A (Electrical Engineering Dep, Stanford Univ, Stanford, CA 94305 USA) : Performance limitations of Si bulk CMOS and alternatives for future ULSI. J Indian Inst Sci 2007, 87(3), 387-400.

Diminishing improvement in the on current (ION) and increase in off current (1_0ff) may limit the scaling of bulk Si CMOS. There are several technical issues that make proper device scaling increasingly difficult. Various techniques like ultra-thin gate dielectrics, shallow source/drain junctions and high channel doping are used to mitigate the short channel effects and improve the device performance. Most of these approaches however directly conflict with the goal of obtaining high carrier mobility, low subthreshold swing, low series resistance, and therefore large ION and low IQFF at low supply voltage. To continue scaling beyond the 22 nm node, various architectural and material changes in the traditional MOSFET would be required for efficient operation of the transistor as a switch. A channel material with high mobility and therefore high injection velocity can increase on current and reduce delay. Currently, strained-Si bulk CMOS is the dominant technology and increasing the strain provides a viable solution to scaling. However, looking into future scaling of nanoscale MOSFETs it becomes important to look at higher mobility materials, like Ge and III-V materials together with innovative device structures, like the multi-gate FETs (MuGFETs) with high-K dielectrics, metal gate and Schottky source/drain. For both Ge and III-V devices problems of leakage need to be solved. Novel heterostructures will be needed to exploit the promised advantages of Ge and III-V based devices.

22 illus, 35 ref

022831   Ravat K B;Mahajan S K (DC High Voltage Standard, National Physical Laboratory, New Delhi-110 012) : Practical aspects which affect an electrical measurement. Indian J Engng Mater Sci 2007, 14(2), 119-24.

Focuses on some of the practical considerations for electrical measurement. Though these are not measurement techniques but have a very significant effect on precision measurement. Some of these are leakage currents, thermal effects, contact resistance, transients, grounding, shielding, earthing, guarding and drift. The precision measurement depends on control of all these important but sometimes subtle factors.

9 illus, 10 ref

022830   Rajagopalan S;Sharma S J;Ghodki V M (Electronics Dep, Nagpur Univ Campus, Nagpur-440 033) : Design of a PC based sing around system. J Instrum Soc India 2007, 37(3), 206-11.

Among the pulse techniques for ultrasonic velocity measurements, sing around technique is very popular and widely used due to its simplicity, better accuracy and reliability. In the present work a PC based sing around technique, operated at 2 MHz, is designed using indigenous components and a PCL 812 card. The system has been developed using the concept of virtual instrumentation and is found suitable for precise ultrasonic velocity measurements in liquids and solids. Software, written in C, controls the pulse generation, detection, re-triggering the input and travel time measurement. The travel time is measured using an 8 MHz crystal as the standard clock. A simple graphical user interface designed in VISUAL BASIC at front-end, controls the various functions involved in the measurements. The system developed in our laboratory has been tested for ultrasonic velocity measurements in different standard liquids. The ultrasonic velocity measurements using the above technique, matches well with those reported in the literature. The system developed is accurate, fast, effective, powerful and reliable for ultrasonic velocity measurements in liquids as well as solids.

2 illus, 1 table, 30 ref

022829   Pathak K K;Ramakrishnan N (NO, Advanced Material and Processes Research Institute (CSIR), Bhopal-462 026, Email: lekpathak@rediffmail.com) : Optimization of die angle and ram velocity for rod extrusion using dynamic material modeling and genetic algorithm. Indian J Engng Mater Sci 2007, 14(6), 399-402.

Selection of processing and geometrical parameters is a crucial step in the extrusion process design. Optimized parameters may result in desirable microstructure at minimum load. To achieve this goal, dynamic material modeling (DMM) and genetic algorithms (GA) are used in this study. Selection of strain rate and temperature is done by DMM which insures dynamic recrystalization (DRX) zone during processing. Minimization of punch load is formulated as a nonlinear programming problem which is solved using GA to result in optimum ram velocity and die angle. Two rod extrusion processes are successfully optimized using proposed approach.

5 illus, 14 ref

022828   Pa P S (Graduate School of Toy and Game Design, National Taipei University of Education, Taipei, Taiwan, ROC, Email: myhow@seed.net.tw) : Design of gear-form electrode and ultrasonic-acid in electrochemical finishing of SNC236 surface. Indian J Engng Mater Sci 2007, 14(3), 202-8.

It is very dificult to execute the finishing process of the complex surface of gears. The ctirrent study oilers a design of gear-form electrode and a new area-finishing process using ultrasonic energy transmitted into the electrolyte to assist in the process of electrochemical finishing on the surface of nickel chromium steels beyond traditional process of gear machining instead of conventional hand or machine polishing. The surface of the gears is electrochemieally finished by different types of feeding electrodes as a finishing operation. In the experiment, three types of electrodes are used with continuous direct current and axial electrode feed applied. The controlled factors include the chemical composition and concentration of the electrolyte, die material, initial gap width, and flow rate of electrolyte. The experimental parameters arc current rating, feed rate of electrode, frequency and power level of ultrasonics, and electrode geometry. To feed gear-form electrodes, an electrode with one-side borer tip with a small base area yields the best polishing effect in the current investigation. For the design electrodes, a thin plate with small end radius and small wedge angle are associated with higher current density and provides larger discharge space and better polishing effect. The electrode with a spherical head performs the best. The higher current rating with ultrasonic assistance can avoid the difficulty of dreg discharge, thus reducing the finishing lime. It is a great contribution that the ultrasonic-aided electrochemical finishing after gear machining needs a much shorter time than manual or machine polishing to make the surface of gears smooth and bright. An effective and low-cost finishing of the surface of castings is presented.

12 illus, 26 ref

022827   Noori K;Haider S A (Electrical Engineering Dep, Military College of Signals, National University of Sciences and Techn, Pakistan, Email: khalida@mcs.edu.pk) : Layered MIMO-OFDM system with channel equalization. J Digital Inf Mgmt 2007, 5(6), 361-3.

Simple and efficient method for layered MIMO-OFDM system with channel equalization is proposed. Temporal variations in the channel are due to Doppler spread, a sign of relative motion between transmitter and receiver. Results are simulated in both Rayleigh channel and additive white Gaussian noise (A WGN) channel. Decision feedback equalizer (DFE) with recursive least square (RLS) algorithm is used for channel equalization. Different type of Layered structure is applied to MIMO-OFDM system and their performance is evaluated. Different modulations schemes are used with same number of transmit and receive antennas. Simulation results are shown for both vertical and horizontal coded layered structure MIMO-OFDM systems with different modulation schemes and different number of transmit antennas.

8 illus, 6 ref

022826   Nickolas S;Rao C S P;Reddy A V;Asokan P (National Institute of Technology, , Trichirappalli, Email: nickolas@nitt.edu) : Performance enhancement of flow shop scheduling using data mining. Mfg Technol Today 2007, 6(8), 17-23.

Data Mining aims at discovering knowledge consisting of rules describing properties of data. The optimized schedules for a flow shop scheduling problem are generated by the metaheuristic methods. The optimal schedules are used to generate the training set by identifying the predictor attributes affecting the schedules. The classifier model is generated based on decision tree induction by discretising the data in the training set based on chi2 algorithm. The classifier model is tested by applying for the new set of problems. The optimized schedule is generated by the classifier model is comparatively equal to that of the scheduling done by the metaheuristic methods. The sees tool is used for performing the data mining classification. Thus the rules generated by the Data Mining classifier allows the production managers to easily take decisions regarding the flow shop scheduling based on various objective functions and constraints.

4 illus, 5 tables, 20 ref

022825   Nashine B K;Dash S K;Gurumurthy K;Kale U; Sharma V D;Parbhakar R;Rajan M;Vaidyanathan G (Fast Reactor Technology Group, Indira Gandhi Center for Atomic Research, Kalpakkam-603 102, Email: bknash@igcar.gov.in) : Performance testing of indigenously developed DC conduction pump for sodium cooled fast reactor. Indian J Engng Mater Sci 2007, 14(3), 209-14.

Liquid sodium is a good electrical conductor and this properly enables utilization ol electro-magnetic (EM) pump for sodium service. Being non-intrusive EM pumps arc well suited to sodium system as the chance of any sodium leak is minimized. However. EM pump utilization is restricted to auxiliary sodium circuit and centrifugal pumps arc preferred for main circuits in view of their higher efficiency. DC conduction type EM pump is utilized lor low flow and high temperature application. It comprises of stainless steel duct through which sodium passes and the magnetic field is produced by an electromagnet covering the duct. A DC conduction pump has been designed, built and tested for its performance in sodium before putting in the reactor. Presents the design approach and the performance vis-avis prediction.

7 illus,

022824   Nair R K;Manmeet kaur;Pradeep R;Katti V R; Gadkari S C;Gupta S K (Technical Physics & Protoype Engineering Div, Bhabha Atomic Research Centre, Mumbai-400 085) : Development of H S detector. J Instrum Soc India 2007, 37(3), 176-81.

Metal oxide semiconductor (SnO₂: CuO) thin film based sensor and a detector to sense H₂S in the 5-50ppm range, present in the ambient. Sensor films were prepared by thermal evaporation of tin and copper metal on recrystallised alumina substrate followed by oxidation at high temperature. Response and recovery times of the sensor film were measured at different temperatures and optimum operating temperature was found to be 200°C. The sensors are hence operated at about 200°C using a controller circuit that has been designed to maintain the sensor film temperature within ± 0.5°C. The sensor is very selective, exhibits high sensitivity (<62>10⁴ in SOppm H₂S) and short response time (80s) at this operating temperature. An instrument has been developed to detect H₂S in ambient air and also provide audio alarms when the gas in the vicinity of the sensor exceeds preset limits. The instrument continuously monitors proper functioning of the sensor heater and indicates status on the front panel. It also has provisions for sensor calibration.

5 illus, 5 ref

022823   Malathy R;Subramanian K (Civil Engineering Dep, Kongu Engineering College, Perundurai-638 052, Email: malathycivil@kongu.ac.in) : Drying shrinkage of cementitious composites with mineral admixtures. Indian J Engng Mater Sci 2007, 14(2), 146-50.

Emphasises on the influence of mineral admixtures (MA) like silica fume, metakaoline and fly ash on the drying shrinkage of cement mortars incorporated with MA as cement replacement material. MA has been varied at different percentages from 0 to 15% at the constant increment of 5%. The water-binder (cement + MA) ratio and binder-sand ratios are 0.5 and 1:3 respectively. The short-term and long-term ultimate drying shrinkage of mortar has been studied. The effect of size of sand particles has been studied with different sizes of particles fractions. The highest drying shrinkage has been observed in mortars with higher silica fume contents at the age of 28 days. At the early ages, this has been due to the high pozzolanic reaction of silica fume, as a result of pore-size refinement mechanism of silica fume. However, the effect of silica fume has not been significant on the long-term drying shrinkage. The effect of grain size demonstrates that the ultimate drying shrinkage decreases as the size of sand particles increases.

4 illus, 4 tables, 25 ref

022822   Mahadevan K;Raghukandan K;Pai B C;Pillai U T S (Mechanical Engineering Dep, Pondicherry Engineering College, Pondicherry-605 014) : Experimental investigation on the influence of reinforcement and precipition hardening parameters of AA 6061-SiCp composites. Indian J Engng Mater Sci 2007, 14(4), 277-81.

The presence of discrete reinforcement particles in the matrix of the discontinuously reinforced metal matrix composites considerably alters the matrix microstructure and hence the precipitation hardening kinetics. Therefore, precipitation hardening schedule of aluminium alloys are not applicable to aluminium matrix based discontinuously reinforced composites. In the present work, an attempt has been made to systematically study the effects of reinforcement percentage and precipitation hardening parameters on the behaviour of AA 6061-SiC_p composites. The result reveals that AA 6061-SiC_p composites demand longer solutionizing time (3 h) compared to unreinforced AA 6061 alloy (I h). Moreover, successively during artificial aging, the time required to attain peak aging condition is shorter and almost same for AA 6061-SiC_p composites irrespective of percentage of reinforcement.

6 illus, 2 tables, 16 ref

022821   Livaoglu R;Dogangun A (Civil Engineering Dep, Karadeniz Technical Univ, 29000 Gumushane, Turkey, Email: rliva@ktu.edu.tr) : Seismic behaviour of cylindrical elevated tanks with a frame supporting system on various subsoil. Indian J Engng Mater Sci 2007, 14(2), 133-45.

The seismic responses of an elevated tank with a frame supporting system on various subsoils are investigated. The finite element method is used for the modelling of the elevated tank and subsoil system. Fixed-base and elastic media assumptions are made for subsoil. The tank fluid has been modelled as lumped masses such as impulsive and convective masses proposed by Housner. An added mass approach is used for fluid-structure interaction by representing both the impulsive mass and the convective mass. For estimating the seismic response of elevated tanks, response spectrum analysis with mode superposition is used. The results obtained from modelling the elevated tanks on a fixed base and on an elastic medium are compared. It has been observed that the seismic response of the elevated tank is altered significantly depending on the properties of the subsoil. The soil-structure interaction especially affects the impulsive modes and lateral displacement of elevated tanks rather than the torsional modes. It is proposed that the coupling effect for perpendicular directions in the axisymmetrical plan geometry should be considered in the seismic design of the elevated tanks.

14 illus, 2 tables, 41 ref