004712   Srinivasan R;Bhat N (Dep of Electl Commun Engng, Indian Inst of Sci, Bangalore-560 012, Email: sreenivaasan@ece.iisc.ernet.in) : Scaling characteristics of f_nos and f_t in N_mosfet with and without supply voltage scaling. J Indian Inst Sci 2005, 85(4), 195-200.

Extensive process and device simulations are performed to investigate the nonquasi-static transition frequency (f_NQS) behaviour of the NMOSFETs at different technology nodes, 0.5 μm to 90 nm, having same off-state leakage current (I_OFF). These studies are done without without supply voltage scaling. f_NQS exhibits a turnaround in the 100 nm regime when do the supply voltage scaling along with the transistor scaling. Attribute this effect to the reduced gate overdrive (V_GS-V_t) and thereby to the degraded transconductance (g_m). The unity gain frequency (f_t) also shows a similar trend. The turnaround effect of f_NQS and f_t disappears when I_OFF is allowed to go up or the gate overdrive is increased or both.

5 illus, 1 table, 18 ref

004711   Srilatha N S;Murthy G S (Dep of Molec Reproduction Dev and Genet, Indian Inst of Sci, Bangalore-560 012, Email: gundlupetmur@indiatimes.com) : Electrostatic interaction in BIAcore binding studies: A cause for anomaly. Curr Sci 2006, 90(5), 677-82.

Sensograms of human chorionic gonadotropin-mono-clonal antibody (hCG-MAb); ligand-ligate binding in the BIAcore were analysed. Surface-bound MAb in 0.1 M phosphate buffer was unaltered by the concentration of MAb (CMAb) as well as pH of the sensogram. Surprisingly, at 0.01 M phosphate buffer concentration surface-bound MAb markedly decreased (300%) at pH 9. At low ionic strength Bovine Serum Albumin (BSA), a nonspecific protein, bound to the uncoupled (control channel) chip at pH 5, but not at 7. BSA so bound did show a dissociation profile like MAb, with fast and slow dissociating components. Binding of BSA to the chip at low ionic strength clearly established the presence of salt-dependent interaction between the protein and chip matrix. A model is proposed which rationally explains, on the basis of electrostatic interaction, the association and dissociation anomalies often encountered in the BIAcore sensograms.

5 illus, 6 tables, 12 ref

004710   Sirimanne P M;Senevirathna M K I;Premalal E V A;Pitigala P K D D P (NO, Inst of Fundamental Stud, Hantana Road, Kandy, Sri Lanka, Email: psirimanne@hotmail.com) : A Soild-state solar cell sensitized with mercurochrome. Curr Sci 2006, 90(5), 639-40.

3 illus, 13 ref

004709   Sharma R;Sha O P (Dep of Ocean Engng and Nav Architecture Des Lab, Indian Inst of Technol, Kharagpur-721 302, Email: rajivatri@yahoo.com) : A tracing method for parametric Bezier triangular surface/plane intersection over triangular domain. J Indian Inst Sci 2005, 85(4), 161-82.

Surface/plane intersection problem is a special case of surface/surface intersection, and is an active area of research across many disciplines in computer-aided geometric design. In general the setting of derivational continuities, (i.e. C⁰, C¹, and C²), a surface/plane intersection algorithm for parametric Bezier triangular surface over triangular domain has been presented. Algorithm is a combinatorial algorithm that is based on a tracing method, in which the intersection curves are traced out in the direction of tangent vectors at intersection points. The intersection curves are represented by their piecewise polynomial approximations, given by ordered pair of surface domain points. The aim is to obtain the smallest number of ordered points that correctly represent the topology of the true intersection curves. Since the points on the intersection curves are obtained in an ordered manner, no sorting is essential. The refinement of the intersection curve may include fitting an interpolatory cubic spline, or adding and deleting points. The method has been used to compute different planar sections (i.e. intersection curves with X, Y, and Z planes) for surfaces having different derivational continuities (i.e. C⁰, C¹ and C²).

13 illus, 40 ref

004708   Sekaran N C (River Basin Res Cent, 1-1 Yanagido GIFU Univ, Japan, Email: Natarajan@green.gifu-u.ac.jp) : Laser ablation - inductively coupled plasma mass spectrometry for 2D mapping of trace elements in soft tissues. J Indian Inst Sci 2005, 85(4), 223-34.

Metals are not homogeneously distributed in organ tissues. Although most mapping techniques such as histologic staining methods, have been developed for element imaging on a subcellular level, many suffer from either low precision or poor detection limits. Therefore, small variations in elemental distribution cannot be identified. Developed a method for two-dimensional mapping of trace elements to identify the influence of metabolic zonation by the liver on trace element distribution.

10 illus, 3 tables, 29 ref

004707   Sekar I;Singh J P;Durga Rao K H V (NO, Indian Agric Res Inst, Pisa campus, New Delhi-110 012) : Planning suitable sites for water harvesting structure in Bandal watershed-RS & GIS approach. Productivity 2005, 46(2-3), 260-4.

Water harvesting structures are essential to conserve water and soil. Potential sites for constructing different water harvesting structure are identified in the Bandal watershed, through remote sensing and Geographic information.

7 illus, 1 table, 6 ref

004706   Sarma K L N;Chidambaram M (Dep of Chem Engng, Indian Inst of Technology-Madras, Chennai-600 036, Email: chidam@iitm.ac.in) : Centralized PI/PID controllers for nonsquare systems with RHP zeros. J Indian Inst Sci 2005, 85(4), 201-14.

Two centralized controller-tuning methods, Davison's method [Multivariable tuning regulators: The feed forward and robust control of general servo mechanism problem, IEEE Trans. Auto. Control, 21, 35-21 (1976)] and Tanttu and Lieslehto method [A comparative study of some multivariable PI controller tuning methods, in Intelligent tuning and adaptive control, Pergamon Press, pp 357-362 (1991)], are extended to nonsquare systems with right half-plane zeros. These methods have been applied to two examples with right half-plane zeros in the individual scalar elements-coupled pilot plant distillation columns (2 outputs and 3 inputs) and a crude distillation process (4 outputs and 5 inputs). Simulation studies have been carried out for these examples for both servo and regulatory problem. For the coupled pilot plant distillation column example, the proposed methods are compared with the robust decentralized controller design method proposed by Loh and Chiu [Robust decentralized control of nonsquare systems, Chem. Engng Commun., 158, 157-180 (1997)]. The performance of square and nonsquare controllers is compared for the crude distillation process example.

5 illus, 7 tables, 12 ref

004705   Rudolph T (Philips Semiconductors GmbH, , Hamburg, Germany) : Integration of vehicle theft prevention and keyless entry. Elect Inf Plann 2006, 33(7-8), 207-12.

As vehicle theft is growing, customers and insurance companies seek for implementing effective theft prevention measures, since vehicle alarm systems, already in place for many years, hardly prove to keep theft rates low. A contactless transponder integrated in the vehicle key became the state-of-the-art technique for vehicle theft prevention by immobilising the vehicle. Measuring a few millimetres only, the transponder can easily be integrated into a vehicle key not bothering the user at all. A corresponding control unit embedded in the vehicle does provide the transponder power supply and triggers the authentication process. Inexpensive and tamper prove system have been designed that prove their effectiveness in Europe, US and Asia now for many years. Introduced in Europe in 1993, theft rates of transponder equipped vehicles reduced by more than 90 per cent and thus significantly reduced insurance claims as well as led to bonus programmes to the benefit of the vehicle owners. Philips Semiconductor is the leading supplier for immobilisation transponders, base station ICs and comb-chip ICs for keyless entry and keyless entry/start. System cost reduction and increased convenience in the field of vehicle entry and engine start is achieved by cutting edge technology that will revolutionise the way of vehicle access, replacing today's mechanical key and enabling new vehicle lock concepts.

7 illus, 1 ref

004704   Patel H A;Somani R S;Bajaj H C;Jasra R V (Div of Silicates and Catalysis, Cent Salt and Mar Chemicals Res Inst, G.B. Marg Bhavnagar-364 002, Email: hcbajaj@csmcri.org) : Nonoclays for polymer nanocomposites, paints, inks, greases and cosmetics formulations, drug delivery vehicle and waste water treatment. Bull Mater Sci 2006, 29(2), 133-45.

Nanoclays or organically modified layered silicates (organoclays) is presented with emphasis placed on the use of nanoclays as the reinforcement phase in polymer matrices for preparation of polymer/layered silicates nanocomposites, rheological modifier for paints, inks and greases, drug delivery vehicle for controlled release of therapeutic agents, and nanoclays for industrial wastewater as well as potable water treatment to make further step into green environment. A little amount of nanoclay can alter the entire properties of polymers, paints, inks and greases to a great extent by dispersing 1 nm thick layered silicate throughout the matrices. The flexibility of interlayer spacing of layered silicates accommodates therapeutic agents which can later on be released to damaged cell. Because the release of drugs in drug-intercalated layered materials is controllable, these new materials have a great potential as a delivery host in the pharmaceutical field. The problem of clean water can be solved by treating industrial and municipal wastewater with organo-clays in combination with other sorbents like activated carbon and alum. Organoclays have proven to be superior to any other water treatment technology in applications where the water to be treated contains substantial amounts of oil and grease or humic acid.

7 illus, 3 tables, 76 rer

004703   Nag A K;Praveen K V U;Singh V (Dep of Metall Engng, Inst of Technol Banaras Hindu Univ, Varanasi-221 005, Email: vakil@bhu.ac.in) : Effect of heat treatment on tensile behaviour of Ti-6Al-5Zr-0.5Mo-0.25Si alloy. Bull Mater Sci 2006, 29(2), 147-54.

Tensile behaviour of the near α titanium alloy, Ti-6Al-5Zr-0.5Mo-0-25Si (LT26A), was investigated in (α+β) as well as β treated condition, over a wide range of temperature from RT to 823 K. It was observed that there were distinct serrations on the load-elongation curves of the α+β treated material at intermediate temperatures from 623 to 723 K. Tensile tests at 673 K over a wide range of strain rate from 0.052 to 5.60 (x10^-2) s^-1 showed negative strain rate sensitivity. Thus, occurrence of DSA was confirmed. It was established from the measured activation energy for DSA that it was essentially controlled by diffusion of the solid solution strengthener silicon in the matrix.

14 illus, 6 tables, 17 ref

004702   Murugan V;Kulkarni M;Anand R M;Kumar E P; Suresh B;Reddy V M (Dep of Pharm Chem, J.S.S. Coll of Pharm, Rocklands, Post Box No. 20, Ootacumand-643 001, Email: murugan62@yahoo.com ) : Synthesis of 2-[{Bis-(2-chloroethyl)amino}methyl]-6,8-dinitro-1-(4-substituted phenyl)-1H-quinazolin-4-one derivatives as possible antineoplastic agents. Asian J Chem 2006, 18(2), 900-6.

Synthesis of six 2-{[bis-(2-chloroethyl)amino]methyl}-6,8-dinitro-1-(4- substituted)-1H-quinazoline-4-one derivatives is reported. The compounds contain nitro groups at positions 6 and 8 of quinazolinone moiety and a phenyl group at position 1. All the six compounds were incorporated with nitrogen mustard moiety. The synthesized compounds were screened for their anticancerous activity by short-term in vitro antitumor activity and in vivo anticancer activity by body weight analysis, mean survival time and percentage increase in life span methods in Swiss albino mice bearing DLA 1 x 10⁶ cells/mL. Out of six compounds studied, compound nitro-derivatives showed significant anticancer activity.

3 tables, 17 ref, 1 scheme

004701   Muniappan A;Duriyanandhan V;Dhanaraj R (Dep of Aerospace Engng, Madras Inst of Technol Anna Univ, Chennai-600 044, Email: dhanaraj@yahoo.com) : Unsteady aerodynamic characteristics of the flapping wing micro air vehicle (MAV). J Aerospace Sci Technol 2006, 58(1), 14-21.

Flapping wing propulsion is center of attention in the field of micro air vehicle research in recent years. Knowledge in unsteady aerodynamics is insufficient to design an efficient wing that produces the required lift and thrust force for the flapping wing micro air vehicle. The unsteady aerodynamic effects on aerodynamic wing design parameters were discussed The effect of aspect ratio and the wing planform shape on lift and thrust force were determined experimentally. The experiments were conducted in an open jet low speed wind tunnel having test section 350 mm x 350 mm. A rack and gear type new flapping mechanism was designed and fabricated and this was used as test bed for all the experiments. Also an experiment was conducted to determine the effect of torsional flexibility of the wing. The result shows that the chord wise flexible wing produces more lift and thrust than the other wing.

16 illus, 2 tables, 12 ref

004700   Mullick A N;Majumder B (Dep of Mechanical Engng, FIEM, Kolkata-700 150, Email: b_maj3255@yahoo.com) : Experimental investigation of flow parameters in a mild curved s-shaped diffusing duct. J Aerospace Sci Technol 2006, 58(1), 22-30.

Detailed study of the performance of fully developed subsonic turbulent flow in a circular cross-section S-shaped centerline-diffusing duct. A precalibrated 5-hole pressure probe was used for the measurements. The diffuser cross-section was expanded to 2.25 area ratio (Ar) at the exit. The duct was fabricated by joining two 22.5° bends of curvature ratio β_t 11.46 in reverse direction with a centerline offset of 0.2 of the axial length of the diffuser. The test was carried out with inlet R_e=8.4 x 10⁵, calculated based on diffuser inlet diameter. The. experimental results indicated the generation of secondary flow in the form of a pair of counter rotating vortices in the first half, which changes its senses of rotation in the second half. The overall static pressure recovery of the diffuser was 40%.

10 illus, 2 tables, 16 ref

004699   Mittal V;Kasana K S;Thakur N S (Dep of Mechanical Engng, BRCM Coll of Engg. & Tech., Bahal (Haryana), Email: vmittal231@rediffmail.com) : Performance evaluation of solar absorption cooling system of Bahal (Haryana). J Indian Inst Sci 2005, 85(5), 295-305.

Presents the modeling of a solar-powered, single-stage, absorption cooling system using a flat plate collector and water-lithium bromide solution. A modular computer program has been developed for the absorption system to simulate various cycle configurations with the help of weather data of village Bahal, Distt. Bhiwani, Haryana, India. The effects of hot water inlet temperatures on the coefficient of performance and the surface area of the absorption cooling component are studied. Also studied is the effect of reference temperature, which is the minimum allowable hot water inlet temperature on the fraction of total load met by nonpurchased energy and coefficient of performance.

7 illus, 2 tables, 18 ref

004698   Manvi S S;Flexwala A;Singh A (Dep of Electron and Commun Engng, Basaveshwar Engng Coll, Bagalkot-587 102, Email: agentsun2002@yahoo.com) : A dynamic bandwidth allocation scheme for VSAT-based networks. J Indian Inst Sci 2005, 85(4), 183-93.

The limited bandwidth available to an organization through an expensive gateway like VSAT (very small aperture terminal) requires proper and effective utilization. Proposes a scheme, which allocates bandwidth to applications based on priorities, application metric weights coupled with max-min fairness approach. The applications requiring less bandwidth are fulfilled before the applications requesting for more bandwidth that come under same priority classes. The scheme is devised such that applications within the same priority are allocated bandwidth by using max-min fairness technique. The scheme is simulated and its performance is evaluated in terms of several performance parameters like bandwidth utilization, application rejection and bandwidth allocation. The simulation result shows that the proposed scheme can be used to cater to the needs of prioritized applications effectively. The flexibility, robustness and least mathematical complexity of the scheme make it suitable for networking applications over VSAT.

12 illus, 1 table, 21 ref

004697   Kilic A M;Kilic O;Ekrem Aritan A (Dep of Min Engng, Cukurova Univ, Adana, Turkey 01330, Email: zenkilic@cu.edu.tr ) : Duvertepe kaolin deposits in Belikesir (North west Turkey) and ceramic properties. Asian J Chem 2006, 18(2), 1352-60.

Duvertepe kaolin deposits (Caltilitaban and Bagkiran) were characterized and assessed potentially in the ceramic industry. The particle size, colour measurement, viscosity, plastic limits, liquid limits, firing shrinkage, water absorption, water-soluble matter and moisture were tested by chemical, physico-mechanical, mineralogical and the thermal analysis techniques (TG-DTA) and their firing behaviours were investigated. The technological properties of Duvertepe kaolins were determined concerning shrinkage, firing and colour. From these studies, it was understood that the Duvertepe kaolin could be used for ceramic industry, fabrication of tiles, bricks and sanitary wares.

4 illus, 3 tables, 20 ref

004696   Kashyap S K;Naidu V P S;Singh J;Girija G;Raol J R (Div of Flight Mechanics and Control, Natn Aerospace Laboratories Multi Sensor Data Fusion Lab, Post Box No. 1779, Bangalore-560 012, Email: ggirjia@css.nal.res.in) : Tracking of multiple targets using interactive multiple model and data association filter. J Aerospace Sci Technol 2006, 58(1), 65-74.

Tracking of multiple targets using interactive multiple model and data association filter has been developed on PC MA TLAB. The performance of the algorithm is evaluated in terms of estimated and measured tracks in presence of clutter, mode probability, standard deviation, root mean square position error and with varieties of simulated scenarios. Sensitivity of the algorithm to the choice of tracking models and process noise covariance values has been studied. This algorithm has also been evaluated for multi sensor multi target scenario using fusion technique. It was observed that interactive multiple model probabilistic data association filter gives a realistic confidence in the estimates during maneuvers and lower RSSPE during the non-maneuvering phase of the targets.

7 illus, 1 table, 4 ref

004695   Kashyap K T;George R (NO, MS Ramaiah Inst of Technol MSRIT Post, Bangalore-560 054, Email: ktkashyap@msrit.edu) : Mechanism of cube grain nucleation during recrystallisation of deformed commercial purity aluminium. Bull Mater Sci 2006, 29(2), 197-200.

Cube texture is a sharp recrystallization texture component in fcc metals like aluminium, copper, etc. It is described by an ideal orientation i.e. (100) <60>100<62>. The subject of cube texture nucleation i.e. cube grain nucleation, from the deformed state of aluminium and copper is of scientific curiosity with concurrent technological implications. There are essentially two models currently in dispute over the mechanism of cube grain nucleation i.e. the differential stored energy model founded on the hypothesis proposed by Ridha and Hutchinson and the micro-growth selection model of Duggan et al. Calculations are made on the proposal of Ridha and Hutchinson model and the results are ootained in favour of the differential stored energy model. It is also shown that there is no need for the micro-growth model.

4 illus, 1 table, 14 ref

004694   Karthikeyan B;Gopal S;Venkatesh S (NO, SEEE SASTAR Deemed Univ, Tirumalaisamudram, Thanjavur-613 402, Email: karthik@eee.sastra.edu) : A heuristic complex probabilistic neural network system for partial discharge pattern classification. J Indian Inst Sci 2005, 85(5), 279-94.

Partial discharge (PD) pattern classification has recently become popular since the automated acquisition of PD signals has become vital and cogent. A novel method for identification of defects due to partial discharge has been described. Starting from different PD families of specimen, several sets of characteristic vectors are determined and then used as input variables to the proposed neural network. The innovative trend of using probabilistic neural network (PNN) towards classification of PD patterns is coherent and perceptible. Elucidates the structure of PNN, which has been appropriately customized for determining the optimum value of smoothing parameter. PD is measured using the conventional discharge detector and previously developed statistical tools that processed the PD patterns. Satisfactory results in the past have revealed that the analysis of the properties of the phase position distributions can be made using mathematical descriptors. The ability of PNN to classify these descriptors in addition to classifying the inputs derived from the measures based on central tendency, dispersion, and maximum and minimum values are investigated. The classification of single-type insulation defects has been envisaged. Also expounds a novel complex technique adopted for precise PD classification.

8 illus, 3 tables, 16 ref

004693   Kapil;Mukesh Kumar;Moudgal A;Garg S P (Dep of Soil & Wat Engng, CCS Haryana Agric Univ, Hisar-125 004) : Study of demand and supply of irrigation water in a canal command area in Western Haryana. Ann agric biol Res 2006, 11(1), 101-4.

Study of demand and supply of irrigation water through canal network was carried out in a command area of a minor "Kaimari" in western Haryana during 2001-02. The demand and supply of irrigation water in the command area of the minor was studied for the two years 1999-2000 and 2000-01 for the then existing cropping pattern. And it was found that the relative water supply (RWS) through the minor was less than one for most of the time for the both years. But the RWS was higher than one for some short periods also. Therefore, the demand was higher most of the time than supply of irrigation water.

1 illus, 2 tables, 3 ref

004692   Kaliappan S;Sathish C;Nirmalkumar T (Cent for Envir Stud, Anna Univ, Chennai-600 025, Email: drkalsun@yahoo.com) : Recovery and reuse of water from effluents of cooling tower. J Indian Inst Sci 2005, 85(4), 215-21.

Membrane technology is emerging as a viable and economical option in the reclamation of wastewater. Involves the feasibility of recycling and reusing the wastewater let out from a fertilizer unit. Cooling water blowdown from the waste stream has high salt concentration. An economically and technically viable reverse osmosis process has been employed to treat the wastewater. Feed water needs to be pretreated to apply reverse osmosis process. Effluents from the cooling tower of the fertilizer unit contained about 50 mg/l of suspended solids and need to be removed prior to treatment with reverse osmosis unit to remove total dissolved solids (2500 mg/1). Pre-treatment with a microfilter of sizes 5 and 1 μm and carbon filter completely removed the suspended solids achieving a silt density index of 5. Pretreated water was sent to the reverse osmosis system, maintained at operating pressures of 275 x 10³, 310 x 10³, 344 x 10³, 379 x 10³ and 413 x 10³ Pa, to reduce the level of the total dissolved solids. The best, level of TDS (270 mg/l) was achieved at a maximum pressure of 413 x 10³ Pa. The maximum amount of salt rejected by the membrane was 89.2% and the maximum recovery of 56.0% was obtained at a pressure of 413 x 10³ Pa.

2 illus, 2 tables, 16 ref

004691   Juan W;Yajiang L;Yansheng Y (Key Lab of Liq Struct and Heredity of Mater, Ministry of Educ Shandong Univ (South Campus), Jinan-250 061, P.R. China, Email: jwang@sdu.edu.cn) : Microstructural characterization in diffusion bonded TiC-Al2O3/Cr18-Ni8 joint with Ti interlayer. Bull Mater Sci 2006, 29(2), 155-8.

Ceramic matrix composite, TiC-Al₂O₃, and stainless steel, Crl8-Ni8, were joined at 1400 K by solid state diffusion bonding, making use of a Ti foil acting as thermal stress relief interlayer. The microstructure of the joint was thus formed. The diffusion bonded TiC-Al₂O₃/Cr18-Ni8 joint was investigated by a variety of characterization techniques such as scanning electron microscope (SEM) with energy dispersion spectroscopy (EDS) and X-ray diffraction (XRD). The results indicate that Ti foil is fully fused to react with elements from substrates and Ti₃Al, TiC and α-Ti are formed in the diffusion bonded TiC-Al₂O₃/Cr18-Ni8 joint. The interfacial shear strength is up to 99 MPa and the shear fracture occurs close to the ceramic matrix composite due to the application of Ti foil acting as thermal stress relief interlayer.

7 illus, 1 table, 8 ref

004690   Iyer S;Sinha S K (Dept. of Civ & Envir Engng Pipeline Infrastructure Res Cent (PIRC), The Pennsylvania St Univ Univ Park PA 16802, USA, Email: shiv@psu.edu) : Automated condition assessment of buried sewer pipes based on digital imaging techniques. J Indian Inst Sci 2005, 85(5), 235-52.

Assessing the condition of underground pipelines such as water lines, sewer pipes, and telecommunication conduits in an automated and reliable manner is vital to the safety and maintenance of buried public infrastructure. In order to fully automate the condition assessment of buried pipes, it is necessary to develop a robust defect analysis and interpretation system. Development of an automated defect detection system for sanitary sewer pipelines using digital imaging techniques like contrast enhancement, mathematical morphology and curvature evaluation has been presented.

15 illus, 32 ref

004689   Ghosh A K;Sagoo G;Singhal A (Dep of Aerospace Engng, Indian Inst of Technol, Kanpur-208 016, Email: akg@iitk.ac.in) : Wind tunnel investigation of typical strategic missile configuration at high angle of attack. J Aerospace Sci Technol 2006, 58(1), 75-81.

The present wind tunnel investigation is a part of a project studying the effectiveness of flat fin control on short-range strategic missile at high angle of attack. As a part of this program, the longitudinal aerodynamic coefficients were computed analytically and were compared with estimates obtained through wind tunnel testing. Wind tunnel tests were conducted over a range of angle of attack from -15° to +45° at a free stream speed of 60m/s. Aerodynamic coefficients were generated for various missile configurations. These coefficients were then compared with the estimates obtained analytically. It was conjectured that, at high angle of attack, vortices shaded by the body interact with the local flow near the fins and drastically alters the stability characteristics of the missile. The subject missile has a small hemispherical nose as compared to most of the missiles having conical or ogival nose. For such a configuration sufficient theoretical/experimental data are not available. Thus, it was important to generate longitudinal aerodynamic data for the range of angle of attack upto which the theoretical model can be used to evaluate the aerodynamic stiffness of the missile. Such a model structure is required for postulating aerodynamic model in estimation algorithm, used for parameter estimation from flight data of the subject missile.

4 illus, 1 table, 4 ref

004688   Ganapathi M;Prakesh T;Sundararajan N;Singha M K (Dep of Appl Mechanics, Indian Inst of Technol Delhi, Hauz Khas, New Delhi-110 016) : Large amplitude free flexural vibrations of functionally graded plates. J Aerospace Sci Technol 2006, 58(1), 50-64.

The nonlinear formulation developed based on von Karman's assumptions is employed to study the large free flexural vibration characteristics of functionally graded material (FGM) plates subjected to thermal environment. Temperature distribution is uniform over the plate surface and varied in thickness direction only. Material properties are assumed to be temperature dependent and graded in the thickness direction according to simple power law distribution. The nonlinear governing equations obtained using Lagrange's equations of motion are solved using finite element procedure coupled with the direct iteration technique. The variation of nonlinear frequency ratio with amplitude is highlighted considering various parameters such as gradient index, temperature, thickness and aspect ratios, skew angle and boundary condition. For the numerical illustrations, silicon nitride/stainless steel is considered as functionally graded material. The results obtained here reveal that the temperature field and gradient index have significant effect on the large amplitude free flexural vibration of the functionally graded plate.

3 illus, 7 tables, 30 ref

004687   Dharani M;Chatterjee A (Dep of Aerospace Engng, Indian Inst of Technol Bombay, Powai, Mumbai-400 076, Email: avijit@aero.iitb.ac.in) : Computational investigation of supersonic jet screech in circular jets using higher-order weno scheme. J Aerospace Sci Technol 2006, 58(1), 83-92.

Computational investigation of supersonic jet screech in imperfectly expanded circular jets is conducted using higher order Weighted Essentially Non-Oscillatory (WENO) scheme based solution of the axisymmetric Navier Stokes equations. The jet screech phenomenon is numerically simulated for an over expanded and an under expanded circular supersonic jet. Sound pressure levels, screech amplitude and frequency are calculated from the pressure history in the flow field and compared with values in literature. Shock cell spacings in the high speed jet are also extracted from numerical simulations and compared with that in literature. Important aspects of a screeching jet observed experimentally, like the interaction of instability waves with the shock train and the contribution of downstream propagating hydrodynamic fluctuations to the creation of the upstream moving acoustic wave in the acoustic feedback mechanism, are also captured in the present computations. The latter phenomenon has been observed experimentally but not reported previously in numerical simulations.

13 illus, 2 tables, 18 ref

004686   Burgi B R;Pradeep T (NO, Asian Inst of Technol, AFE Building, P.O. Box Klong Luang, Pathumthani 12120, Thailand, Email: birgit.buergi@env.ethz.ch) : Societal implications of nanoscience and nanotechnology in developing countries. Curr Sci 2006, 90(5), 645-58.

Nanotechnology, unlike any other technology, can find applications in virtually all areas of human life. In spite of being an infant at its evolution, some of the known issues related to nanotechnology suggest a wide spectrum of potential societal impacts. The current public nano-discourse provides sociology with a unique opportunity to switch from a merely passive, observational role to an active participating one, especially where the key players involved meet to find joint and concerted solutions for development.

2 illus, 34 ref

004685   Bharadwaj L M;Bhalla V;Bharadwaj R (Cent Scientific Instruments Organisation, , chandigarh-160 030) : Opportunities and challenges in bioMEMS and bionano devics manufacturing. Elect Inf Plann 2006, 33(7-8), 200-6.

Nanotechnology and MEMS being new enabling technologies for development of devices, system, components and materials for every sector of the industry and it is predicted that this century will be dominated by industrial revolution through hybrid devices based on MEMS and Nanotechnology. BioMEMS and Bio Nanotechnology take advantage of interfacing nanodevices with innumerable molecular and nano devices working in all living systems and have been perfected by nature over a period spanning billions of years. These devices can be interfaced with available micro and nano-structures to design and develop commercially viable products with higher performance and selectivity. For development of specific devices, the core expertise required is in the domain of interfacing functional and intelligent biomolecules with active surfaces including characterisation for their wide ranging applications in healthcare, agriculture, defence, material science, etc. The market for these technologies is growing very fast with development of new materials and devices, the nanotechnology market has already crossed US $100 billion mark and for MEMS this figure is at US $12 billion. According to James Murday and Mike Roro National Nanotech Initiative the Nanotechnology market is expected to touch US $1 trillion by 2015 out of which materials, electronics and Pharmaceuticals will account for 70 per cent of total market. Some of the areas of active research are novel foods, medical devices, chemical coatings, personal health testing kits, sensors for security systems, water purification units, manned space craft, displays for hand-held computer games, and high-resolution screens. In US, there are more than 400 companies in business in these areas and majority of these are startup companies, Europe and Japan are lagging behind but putting all efforts to increase their share in the world market. Thus MEMS and Nanotechnology have opened unlimited opportunities for fundamental & applied research and innovative high performance miniaturized product development for all sectors of economy.

1 illus

004684   Agarwal G;Jain A;Agarwal S;Kabiraj D;Jain I P (Mater Sci Lab Cent for Non-Conventional Energy Resour, Univ of Raj, Jaipur-302 004, Email: ipjain46@sify.com) : Structural and electrical properties of swift heavy ion beam irradiated Co/Si interface. Bull Mater Sci 2006, 29(2), 187-91.

Synthesis of swift heavy ion induced metal silicide is a new advancement in materials science research. Investigated the mixing at Co/Si interface by swift heavy ion beam induced irradiation in the electronic stopping power regime. Irradiations were undertaken at room temperature using 120 MeV Au ions at the Co/Si interface for investigation of ion beam mixing at various doses: 8x10¹², 5x10¹³ and 1x10¹⁴ cm^-2. Formation of different phases of cobalt silicide is identified by the grazing incidence X-ray diffraction (GIXRD) technique, which shows enhancement of intermixing and silicide formation as a result of irradiation. I-V characteristics at Co/Si interface were undertaken to understand the irradiation effect on conduction mechanism at the interface.

5 illus, 15 ref

003591   Zebbiche T;Youbi Z E (Department of Aeronautics, Faculty of Sciences of Engineer, University SAAD Dahleb of Blida, B.P. 270, Blida, B.P. 270, Blida 09470, Algeria, Email: z_toufik270169@yahoo.fr) : Supersonic plug nozzle conception and comparison to the MLN configuration. J Aerospace Sci Technol 2006, 58(3), 184-96.

A method to design the contour and conception of a plug nozzle of arbitrary shape, but specified exit flow conditions is presented. Severals shapes can be obtained for exit Mach number by changing the specific heats ratio. The characteristics of the nozzle in terms of length, weight and pressure force exerted on the wall are compared to the Minimum Length Nozzle and found to be better. Study is limited to the supersonic mode to not to have the dissociation of the molecules. The design method is based on the use of the Prandtl Meyer function of a perfect gas. The flow is not axial at the throat, which may be advantageous for many propulsion applications. The performance benefits of the plug nozzle compared to the Minimum Length Nozzle are also presented.

28 illus, 5 tables, 21 ref

003590   Violet Dhayabaran V;Rajendran A;Suganya P (P.G. and Research Department of Chemistry, Bishop Heber College, Tiruchirappalli-620 017, Email: viodhaya@sify.com) : Inhibitive action of tryptophan on the corrosion of commercial mild steel in 1.0 M HCl. Bull Electrochem 2006, 22(1), 43-8.

Inhibitive influence of Tryptophan on the corrosion of commercial mild steel in 1.0 M HCl medium has been investigated by weight loss and Polarization studies. The inhibition study by Electrochemical impedance spectroscopic (EIS) method has also been made. The inhibition efficiency determined by the above methods were in good agreement. A plot of θ Vs log C for the adsorption on the mild steel surface is found to have a linear relationship. This observation shows the fact that the adsorption of the compound on mild steel in acid medium obeys Temkin's adsorption isotherm. The polarization curves reveal that the corrosion is predominantly under cathodic control. The inhibition is due to adsorption of the inhibitor at the cathodic sites followed by the formation of an insoluble film. The inhibitor chosen for the study reduces the corrosion significantly by the way of entering the cathodic sites more effectively in 1 M HCl.

4 illus, 4 tables, 24 ref

003589   Velmurugan R;Karthikeyan K (Department of Aerospace Engineering and Composites Technology Centre, Indian Institute of Technology Madras, Chennai-600 036, Email: rvel@aero.iitm.ernet.in) : Damping characteristics of montmorillonite based polyester clay nanocomposites. J Aerospace Sci Technol 2006, 58(3), 213-24.

Experimental study of free vibration and damping characteristics of Polyester/Clay Nanocomposites (PCN) has been presented. PCN are prepared by dispersing Un-modified Motmorillonite day (UMT) and organically modified Montmorillonite clay (MMT) in polyester resin and subsequently cross-linked using Methyl Ethyl Keton Peroxide (MEKP) catalyst at different day concentrations (1,2,3, and 5Wt. %). The X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) show the increasing interlayer d-spacing of both UMT and MMT winch indicates the intercalated composites. Tensile test result shows that the tensile strength and modulus are increased by 55% and 43% for 5Wt % of MMT clay concentration respectively. The impact energy and heat deflection temperatures are increased by 68.27% and 25% for MMT clay respectively. The DMA studies reveal that the storage and loss modulus are increasing monotonically with increase of clay concentration. The Impulse technique and Logarithmic decrement method are used in experimental modal analysis and it is seen that increase of Wt. % of clay in polyester matrix increases the natural frequency and damping characteristics of MMT.

27 illus, 9 tables, 16 ref

003588   Suganthi L;Iniyan S;Samuel A A (College of Engineering, Anna University, Chennai-600 025) : Impact of carbon tax on electricity demand in India. Energy Fuel Users J 2006, 56(1), 35-40.

Nature of energy demand in India is determined by the nature of electricity demand since electric energy is the major contributor of energy requirement in India. Natural sources such as fossil fuels are predominately used to generate electricity. This results in tremendous amount of environmental pollution. Determines the future electricity requirement in two stages. The electricity demand is determined using time series and univariate neural network model. Using standard error and correlation coefficient (R²), the best model is determined and used as an input in the econometric model. The independent variables used in the econometric model include GNP, Population and Wholesale Price Index. Three scenarios are identified: a most probable situation (Most Probable-MP), a high carbon tax being imposed (High Tax-HT), and a low carbon tax being imposed(Low Tax-LT). The electricity requirement for the next decade is predicted for the three scenarios and the range of carbon dioxide emission is determined. It is found that the future electricity requirement during the MP case will be 393050 GWhr during 2010-11. The range of carbon dioxide emission during the MP case will be 291 MT to 441 MT. The imposition of carbon taxes is expected to help in optimising the utilisation of electricity among the end users.

3 illus, 3 tables, 11 ref

003587   Srinivasulu P;Vaidyanathan C V (Structural Engineering Research Centre, CSIR Campus, Taramani, Chennai-600 113) : Framed foundations for high speed machinery: some design and modelling issues. J Struct Engng 2006, 33(1), 45-55.

Turbo generator foundations form an essential part of any power plant complex. Framed type foundations are generally adopted to support these machinery to take advantage of the geometry and the functional aspects involved. These machines are highly complex in design and extremely expensive. Maintenance is a major problem and damage of any form is not desirable. Besides, these machines are expected to run continuously during their service life without stoppage or reduction in output. These high speed rotating machines tend to develop large vibrations due to rotor imbalance, thereby generating high vibratory loads which tend to affect the machine-support system, endangering the structural integrity and causing damage to the rotor components. Such high vibrations have to be prevented or minimized through proper structural design of the supporting frame. Many attempts have been made to model the machine-support system. Highlights the important design and modelling issues and some recent trends in the use of materials, definition of exciting forces and acceptance criteria for amplitudes etc. for this class of structures.

13 illus, 23 ref

003586   Srinivasa Rao K;Prasad Rao K (Metallurgical and Materials Engineering Dep, Indian Institute of Technology Madras, Chennai-600 036) : Partially melted zone in aluminium alloy welds. Indian Weld J 2005, 38(1), 44-55.

Partially Melted Zone (PMZ) of aluminium alloy welds an important region and requires careful attention. This is mainly because PMZ in these materials is weak link in the weldments and is significantly affected by welding parameters. Microstructure changes in PMZ are related not only to welding heat input and techniques, but also depend on the initial thermal history of alloy (for example, whether it is in T-4, T-6 or T-87 condition etc). Interestingly not many detailed studies are available in this respect. In work, effect of prior thermal temper and welding techniques mainly continuous and pulsed current Gas Tungsten Arc Welding (GTAW) on the PMZ behaviour of AA2219 and AA6061 alloys were studied. Susceptibility to liqudation was high in T-6 temper of AA6061 alloy compared to that of T-4 temper and has been attributed to more amount of silicon rich eutectic at the grain boudaries of PMZ. Pulsed current technique was found to improve the resistance to the susceptibility to liqudation in PMZ of AA2219 and AA6061 alloys and is due to the possible reduction in the peak temperature.

16 illus, 8 tables, 40 ref

003585   Shamsher Prakash;Puri V K (Civil, Architecture and Enviromental Engineering, University of Missouri Rolla, Rolla, MO, USA) : Foundations for vibrating machines. J Struct Engng 2006, 33(1), 13-29.

Discusses the methods of analysis for determining the response of foundations subjected to vibratory loads. The design of a machine foundation is generally made by idealizing the foundation- soil system as spring-mass - dashpot model having one or two degrees of freedom. Most machine foundations are treated as surface footing and the soil spring and damping values are determined using the elastic-half space analog. The spring and damping values for response of embedded foundations can also be determined from the elastic half space concept as per Novak's work. The soil spring and damping values can also be obtained following the impedance - compliance function approach. Brief discussion of the predicted and observed response of machine foundations has been presented.

15 illus, 7 tables, 27 ref

003584   Selvaraj P;Ashraf M I;Radhakrishnan P (Aeronautical Development Agency, , Post Box No. 1718, Vimanapura Post, Bangalore-560 017, Email: selva@jetmail.ada.gov.in) : Investigation of lean concepts in aircraft sheet metal parts. J Aerospace Sci Technol 2006, 58(3), 250-7.

The newly evolved paradigm 'lean' which is primarily based on the concepts of elimination of waste (non value added activities), 'respond to change' and 'continuous improvement' has significant impact on the design and manufacture of aircraft parts. The concepts and principles of lean are prevalent in various CAD/CAM methods practiced in aircraft industry. Concurrent engineering, sharing of common data base, design in context, integrated parts design, precision assembly, weight control etc. are a few of the lean parameters realized using CAD/CAM technologies. Automation in sheet metal manufacturing (automated flat pattern development, nesting for minimizing the raw material wastage and CNC router program generation etc.) facilitated eliminating various non-value added activities like raw material wastage, tooling, post formed trimming operations etc. The lean benefits of CAD/CAM technologies for the design of aircraft parts illustrating throught a case study of aircraft sheet metal parts assembly has been presented.

^ssc8 illus, 4 tables, 6 ref

003583   Sarkar S (Department of Architecture, Birla Institute of Technology, Mesra, Ranchi) : Prospects of replacement and reuse of timber in construction industry. NICMAR J Constr Mgmt 2006, 21(1), 18-22.

In maintaining ecological balance and environmental stability, forests play a vital role. Infact, timber is an excellent natural composite material, which has been used by mankind since early ages for house building, agricultural implements, fuel, furniture etc. But with the decreasing forest cover of the country, the country's premier Government Construction Agency, CPWD has banned the use of wood in its construction projects way back in April 1993. The replacement and reuse of recovered solid wood since then has hogged the limelight. While the timber industry has been using wood residues from primary wood processing mills for decades, use of secondary species of timber along with the replacement and reuse of wood has become one of prime importance and has provided a much needed variety in terms of application to the construction industry.

2 tables, 4 ref

003582   Sarkar D;Nagesh M (NO, CEPT University, Ahmedabad, Gujarat) : Enabling structures for construction of under ground metro corridor in soft strata - A case of DMRC, New Delhi. NICMAR J Constr Mgmt 2006, 21(1), 1-7.

Construction of an underground corridor for metro rail needs well-designed earth retaining and supporting systems especially for cut and cover construction during excavation activities. The temporary supporting systems are designed as per the strata in which the corridor is executed. Generally, if the strata is of pure soil with minute quantities of weathered rock, then the temporary supporting systems consist of soldier piles, king piles, sheet piles, secant piles, timber lagging, steel struts and diaphragm walls. For a rocky strata, the excavated rock surfaces are stabilized by shotcreting & rock bolting. Rock anchors can be used as substitute to struts at the junction of soil & rock. All these supporting systems are removed at various stages of construction of the permanent civil structure as per the construction sequences. A case study of Delhi Metro Corridor MClB executed by IMCC JV has been dealt with.

6 i, 1 t, 4 ref, 4 plates

003581   Salem D M S A (NO, National Institute of Oceanography and Fisheries, Kayet bey, Alexandira, Egypt, Email: prof_dalia@yahoo.com) : Corrosion of copper in presence of cationic surfactants. Bull Electrochem 2006, 22(1), 21-9.

Rate of corrosion of copper plates was determined by measuring the limiting current of anodic dissolution of copper in phosphoric acid in absence and in presence of cationic surfactants such as didodecyl dimethyl ammonium bromide, dodecyl pyridinium chloride, and octyl trimethyl ammonium bromide. The rate of corrosion, as represented by limiting current, was found to depend on the phosphoric acid concentration, electrode height and the type of surfactant and its concentration. It was found that the rate of corrosion decreased by an amount ranging from 2.2 to 11.3% depending on the type of surfactant and its concentration. Thermodynamic parameters as well as dimensionless group are given.

8 illus, 8 tables, 18 ref

003580   Ram P V;Vaidyanathan C V;Balaji Rao K;Anoop M B (NO, Birla Institute of Technology & Science, Pilani, Rajasthan) : Application of convex models for robust reliability analysis of block type machine foundations. J Struct Engng 2006, 33(1), 101-7.

Robust reliability analysis aims at estimating the maximum amount of uncertainity that a system can tolerate before failure becomes immient. The application of convex models in the estimation of robust reliability of block type machine foundations has been demonstrated. Integration of convex models with non linear optimization technique to come out with robust desings for block type machine foundations has also been shown. The future research directions highlighting the use of Physical Programming, which belongs to a class of Multi-disciplinary design optimization techniques, for optimal design of block type machine foundations has been indicated.

4 illus, 1 table, 12 ref

003579   Rajesh Kumar;Navtej Singh (Department of Aerospace Engineering, Indian Institute of Technology Kharagpur, Kharagpur-721 302, Email: rajesh@aero.iitkgp.ernet.in) : Comparison of Euler and modified TSP solutions for unsteady transonic flow calculation. J Aerospace Sci Technol 2006, 58(3), 173-83.

Many prediction methods have been developed for the transonic flow calculations, most of them solve the Euler equations. The solution of Euler equations is usually complex and takes long computer time. However, in many practical applications, viz, flutter calculation faster transonic flow calculation is preferred. One such approach is based on modified transonic small perturbation (TSP) theory approach. Modified TSP theory incorporating entropy and vorticity effects has been studied by comparing the results with those of Euler equations. Description of both the Eider solver and the TSP solver incorporating entropy vorticity effects has been presented. The calculated results have been compared with the available experimental results or with available Euler results from literatures. The comparison shows good agreement with the experimental data as well as available data from open literature. The modified TSP code provides acceptable accuracy for most transonic flow calculations. Thus in most cases long computation involved in Euler code can be avoided.

6 illus, 16 ref

003578   Quraishi M A;Ansari F A (Department of Applied Chemistry, Faculty of Engineering and Technology, Aligarh Muslim University, Aligarh-202 002, Email: farhat_aishal6@yahoo.com) : Influence of some triazoles on corrosion and dezincification of brass in ammonia solutions. Bull Electrochem 2006, 22(1), 35-41.

Corrosion and dezincification of 70/30 brass in 5N, 10N and 13.4N NH₄OH solutions in the absence and presence of 4-amino-5-mercapto-3-ethyl-l, 2,4-triazole (AMET), 4-amino-5-mercapto-3-methyl-l, 2,4-triazole (AMMT) and 4-amino-5-mercapto-l, 2,4-triazole (AMT) were studied by weight loss; solution analysis and potentiodynamic techniques. Potentiodynamic polarization studies revealed that all the tested compounds are of mixed inhibitor type. The adsorption of these compounds from the ammonia solution obeyed Langmuir adsorption isotherm.

3 illus, 4 tables, 11 ref

003577   Pandit R K (Madhav Institute of Technology and Science, , Gwalior, M.P) : Links and innovations in construction organization. NICMAR J Constr Mgmt 2006, 21(2), 39-43.

1 illus

003576   Pal T K (Metallurgical Engineering Dep, Jadavpur University, Kolkata) : Diffusion bonding of alumina ceramic and austentic stainless steel. Indian Weld J 2005, 38(1), 32-6.

9 illus, 2 tables, 11 ref

003575   Padhi R (Department of Aerospace Engineering, Indian Institute of Science, Bangalore-560 012, Email: padhi@aero.iisc.ernet.in) : Pilot command implementation in aircrafts: A new approach based on dynamic inversion. J Aerospace Sci Technol 2006, 58(3), 234-50.

A new approach based on dynamic inversion is proposed for implementing pilot commands in an aircrafts. The command inputs from the pilot are assumed to be (i) the normal acceleration and forward velocity commands in the longitudinal mode and (ii) roll rate, height and forward velocity commands in the lateral mode. A major difference here is that the second to the first derivatives (which is used in many published literature). The new approach leads to a significant reduction of tuning parameters in the control design process, which is a major advantage. Detailed derivations of the modified approach are presented with respect to the generic aircraft dynamics model available in [16]. Extensive Six-DOF simulation studies show that, besides the above advantage, the new approach leads to two other additional advantages; namely reduced oscillatory response and reduced control magnitude. In a comparison study with an existing method using the Six-DOF model for Boeing 747 (with the numerical data available in [16]), numerical results clearly show the improved performance of this new approach. Furthermore, in lateral mode a technique for obtaining a corresponding roll rate command from the desired bank angle command is also implemented. Comparison results show improved performance of the new approach with this modification as well.

22 illus, 19 ref

003574   Narang B S (Department of Electrical Engineering, Bhilai Institute of Technology, Bhilai House, Durg-490 001, Email: director_bit@sancharnet.in) : Analysis of chaotic signal processing. Appl Sci Period 2005, 7(3), 145-8.

Chaotic systems are analysed with the background of non-linear systems. The essential features of Chaotic systems that of periodicity and oscillation are basically those of non-linear systems are performed with respect to these two notions. The application of Chaotic systems to the field of signal processing has been presented. Generated a Chaotic time series and a perfectly deterministic time signal. To ensure that the time series generated is truly Chaotic and not purely random performed the tests to find out the correlation dimension. The non-integral signals of the correlation dimension obtained depict the Chaotic behaviour.

9 ref

003573   Nagesh M;Pandit D (School of Construction Management, NICMAR, , Pune) : Assessment of school building vulnerability for earthquake disasters. NICMAR J Constr Mgmt 2006, 21(2), 22-38.

Aims at quantifying the vulnerability of a school building against earthquake in particular which can be generalized to any disaster. The study is confined to some parts of Ahmedabad city. This study was done in the aftermath of January 26 2001 earthquake and the school tragedy that followed. The school buildings were compared with the standard codal provisions for compliance. Totally 40 randomly selected schools lucre surveyed in the study. The non conformance was quantified and graded to get a vulnerability grading. The results show that none of the school buildings are safe against disaster. Ninety percent of the schools come under highly vulnerable category.

6 i, 2 t, 11 ref, 8 plate

003572   Nagaraj B N;Ravindranathan C K (NO, , 22, 13th Main R.K. Layout, 3rd Phase, Padmanabhanagara, Bangalore-560 070) : Dynamic analysis of crusher house and rectification of vibration problem. J Struct Engng 2006, 33(1), 63-8.

Coal crusher house of a power plant with two screens and a crusher mounted on floors had undue vibrations. This crusher house also had provision to accommodate screens and crusher of future unit of power plant. Dynamic analysis was performed on a finite element model of this five storeyed building and problem was identified. Rectification measures were suggested taking into account the future unit with increased equipment sizes. These modifications were carried out successfully.

10 illus, 4 tables, 6 ref

003571   Mishra R K;Navindgi R D;Bhat M N (Gas Turbine Research Establishment, , CV Raman Nagar Post, Bangalore-560 093, Email: mishrark@mail.gtre.org) : Effect of diffuser geometry on the performance of an annular aero gas turbine combustor. J Aerospace Sci Technol 2006, 58(3), 206-12.

Combustor is an important component of a gas turbine engine and its performance governs the overall performance of the engine. The effect of diffuser geometry on the performance parameters of short annular combustors has been presented. Full-scale combustors having similar liner configurations but different diffuser geometry were tested in the combustor test facility for this investigation. The combustor aerothermal characteristics such as light-up behavior, exit temperature pattern factors and combustion efficiency are found to be independent of diffuser geometry. But the major aerodynamic parameters such as diffuser pressure loss, static pressure recoveries etc are significantly affected by the diffuser geometry.

12 illus, 1 table, 9 ref