003547   Bubesh Babu J;Madeswaran G;Dhanasekaran R; Trinath K;Rao A V N R;Prasad N S;Abisekaraj I R (Crystal Growth Centre, Anna University, Chennai-600 025) : Ferroelectric properties and transmission response of PZN-PT single crystals for underwater communication. Def Sci J 2007, 57(1), 89-93.

Single crystal of Pb[(Zn_1/3Nb_{2/3)0.91 Ti0.09]O3 (PZN-PT) at the composition of morphotropic phase boundary (MPB) shows a very high electromechanical coupling coefficient, piezoelectric coefficient, and dielectric constant compared to conventional PZT ceramics. These exceptional properties of these single crystals find enormous applications in medical ultrasound imaging and underwater communication (Sonar). The growth of PZN-PT single crystals has been carried out by bottom-supported flux Bridgman method. There are many growth issues to be addressed during the process of growth. The grown crystals are oriented and cut along <60>001<62> direction with the crystal dimension of 8 x 6 x 1.5 mm³ for further analysis. The oriented crystals were poled at a rate of 1 kV/mm. The poled crystals have been characterised for dielectric, strain and piezoelectric values. Further, the poled specimen were tested for transmitting response at various frequencies in acoustic test facility and the difficulties in their growth.}

5 illus, 5 ref

003546   Bhattacharyya S;Das S K;Dana K;Mitra N K (Clay and Traditional Ceramics Div, Central Glass and Ceramic Research Institute, Kolkata-700 032, Email: swapan@cgcri.res.in) : Titania doped triaxial porcelain: enhancement of strength by controlled heat treatment. Bull Mater Sci 2007, 30(3), 231-4.

Titania doped vitrified triaxial porcelain samples were subjected to controlled heat treatment at different temperatures of 600, 800 and 1000°C with a specific heating schedule. The results revealed that flexural strength of 800°C heat treated sample was significantly enhanced to 60 MPa from its original value of 40 MPa. XRD pattern revealed the formation of mullite in the system both before and after heat treatment and the differences in their growth was ascertained through SEM analysis. The present heat treatment process may be useful to produce high strength porcelain body from a common triaxial system.

5 illus, 2 tables, 12 ref

003545   Bhattacharya S;Appavu Raj R (NO, Integrated Test Range, Chandipur-756 025) : Multi-target tracking in a test range scenario. Def Sci J 2007, 57(3), 343-8.

Integrated Test Range (ITR) handles various types of multiple-target flight trials. To facilitate target tracking and estimation in such multi-target scenario, nearest neighbourhood (NN) technique-based data association algorithm has been adopted at ITR. Discusses the NN-based data association algorithm and its performance in a real flight trial situation by using multiple-target track data from a multi-target tracking radar.

3 illus, 8 ref

003544   Balani K;Agarwal A;McKechnie T (Mechanical and Materials Engineering Dep, Florida International University, 10555 W. Flagler Street, CEAS 3464, Miami, FL-33174, USA, Email: kbalani@yahoo.com) : Near net shape fabrication via vacuum plasma spray forming. Trans Indian Inst Metals 2006, 59(2), 237-44.

Near net shape fabrication substantiates the manifestation of final structure near to the desired shape, therefore can easily cut down the price of finished product contributed by machining. Though conventional powder metallurgy techniques are prominent in fabricating near net shape structures with controlled porosity, it still lags in producing thin walled complex shapes with functionally graded/differential structures. Hence, fabrication of complex near net shapes using Vacuum Plasma Spray (VPS) forming has emerged as innovative rapid prototyping technique for a variety of applications. The nuances of near net shape fabrication by VPS technique have been explained. Few examples of spray formed structures such as hypereutectic aluminum-silicon, nanostructured aluminum oxide, and intermetallic iron aluminide thin sheet have been discussed. A detailed case study of VPS formed thin TaC structure for ultrahigh temperature application has been elucidated via near net shape fabrication.

10 illus, 17 ref

003543   Azam A;Naqvi A (Applied Physics Dep, Z.H. College of Engineering and Technology, Aligarh Muslim University, Aligarh-202 002, Email: azam222@rediffmail.com) : From nuclear tracks to nanotechnology. Chem envir Res 2006, 15(4), 203-10.

Nanotechnology may be new to us but not to the nature which has been experimenting and using it since the day one. The pigments on the wings of beautiful butterflies, the rainbow colours on feathers of a peacock, the shades on fresh roses, the sea shells and solar energy conversion by plants, etc. all exhibit manifestation of nanotechnology which is nothing but the `Art of Nature'. Nature has all along been showing us the way how to use this `Art' but we did not had the `eyes' to see and knowledge to understand. Now with the advent of instruments like Scanning Tunneling Microscope (S1M) and Atomic Force Microscope (AFM), we have the required `nanovision' and now it is possible to see and manipulate atoms and molecules for obtaining desired results.

2 illus, 15 ref

003542   Athawale A A;Bapat M (NO, University of Pune, Pune-411 007) : Synthesis of nanocrystalline PZT by hydrothermal method. Def Sci J 2007, 57(1), 35-9.

Synthesis of lead zirconium titanate by a simple, low-energy consumption hydrothermal means is being reported. The precursor materials have been chosen and the method is tailored so that the process becomes economical and offers low lead loss. The synthesised powders have been analysed by FTIR, XRD, SEM, TEM, and TGA. The results show the formation of tetragonal PZT nanoparticles with an average yield of <126>75 per cent. On the basis of FTIR, the product formation is understood to proceed via the formation of a three metal cation hydroxide complex, that under hydrothermal treatment undergoes conversion directly to form the tetragonal phase of lead zirconium titanate.

^ssc5 illus, 7 ref

003541   Anuradha T V;Ranganathan S (Materials Engineering Dep, Indian Institute of Science, Bangalore-560 012, Email: anu_guhan@yahoo.co.in) : Nanocrystalline TiO₂ by three different synthetic approaches: a comparison. Bull Mater Sci 2007, 30(3), 263-9.

Comparison of the efficiency of three different synthetic routes viz. sol-gel method involving templating, mechanochemical synthesis and combustion synthesis for the production of nanostructured TiO₂, is reported. In the sol-gel method, nanocrystalline TiO₂ is produced when titanium tetraisopropoxide is tem-plated onto dodecylamine which forms the liquid crystalline hexagonal structure and the template is then extracted using 1 : 1 solution of ethanol-hydrochloric acid mixture. Mechanochemical synthesis of nanocrystalline TiO₂ involved mechanical milling of stoichiometric amounts of titanium and cupric oxide in a planetary ball mill using stainless steel vial with wear resistant stainless steel balls. Nanocrystalline TiO₂ is produced by the combustion reaction involving titanyl nitrate and fuels like glycine and citric acid. Nanostructured TiO₂ with an average particle size of <126>14 nm is produced by the sol-gel method whereas the mechanochemical reaction between titanium and cupric oxide resulted in the formation of nanocrystalline TiO₂ with an average particle size of <126>20 nm after 12 h of milling. On the other hand, combustion synthesis resulted in the formation of nanocrystalline TiO₂ with an average particle size of less than <126> 50 nm. The microstructures of nanocrystalline TiO₂ produced by the above three methods are analysed.

9 illus, 23 ref

003540   Anjaneyulu P;Lakshmana Das N;Rao B M; Ramakrishna C (Electronics Dep, Andhra University, Visakhapatnam-530 003, Email: apattem2k2@yahoo.com) : Low-latitude HF Doppler short-period oscillations associated with storm sudden commencements. Curr Sci 2007, 92(4), 502-6.

HF Doppler measurements of F-region vertical plasma drifts (Vz) at a low-latitude station, Visakhapatnam (dip-17°N) in association with two storm sudden commencements (SC*/SC) on 21 February 1994 (during daytime 0902 h UT) and 28 May 1994 (during night time 1357 h UT) are analysed. Measurements of Vz at SCs are compared with the H-field variations of high latitudes down to dip equatorial latitudes. It is found that there is an abrupt enhancement in Vz (or in Dopªpler velocity VD) in coincidence with the main impulse of SC*/SC in both the events. In the case of the first event, upward enhancement in Vz is unusual and is nearly 2 to 3 times that of the usual velocities. Also, in the same event there is a downward trend in Vz prior to this enhancement, after which short-period oscillations (60-90 s) in Vz which are coherent with the magnetic fluctuations at several high latitudes down to equatorial latitudes are observed. The observed changes in Vz (VD) at SCs are discussed in the light of the efªfects of magentosphere-generated electric fields promptly penetrated to these low latitudes by means of transmisªsion of electromagnetic waves through earth-ionosphere waveguide and direct transmission of compressional hydromagnetic waves.

^ssc5 illus, 1 table, 12 ref

003539   Anand G;James A R;Radha Krishna T;Sarah P (NO, St. Martin's Engineering College, Hyderabad-501 014) : Synthesis and characterisation of strontium bismuth titanate ceramics via high-energy mechanical milling. Def Sci J 2007, 57(1), 29-34.

Processing conditions, microstructure, and dielectric properties of strontium bismuth titanate (SBT) were systematically studied. The specimen was synthesised by a mechano-chemical processing route using a planetary ball mill. It is important that the action is vigorous enough to break up loose aggregates and a fine particle size is obtained. The specimen was calcined at 800°C for 4 h. The calcined samples were subjected to cold isostatic pressing (CIP) process and finally sintered at 1200°C for 2 h. A relative density ≈ 90 per cent of the theoretical density was obtained. Pellets having a diameter of l cm and thickness of 1 mm were prepared from the sintered compacts for electrical measurements. X-ray diffraction showed that a single phase with the layered perovskite structure of SBT was formed. Morphological studies were carried out by SEM analysis. Frequency dependence of impedance can provide additional insight into mechanisms controlling the electrical response. Resonance studies were made on poled sample in the frequency range 100 kHz - 20 MHz using an impedance analyser (HP-4294A) interfaced to a computer at room temperature. Dielectric measurements in the frequency range 100 Hz-1 MHz were made using an impedance analyser (HP-4192A) interfaced to a computer and the measurements were carried out from room temperature to 550°C. The ferroelectric hysteresis loop was measured using a standard ferroelectric analyser based on Sawyer-tower circuit. Elastic compliance (S₃₃, S₁₁) coupling factor (k₃₃, k₃₁)were also obtained. These materials can be utilised in practical applications as substitutes for lead titanate and lead zirconate titanate (PZT)-based ceramics, where high temperature applications are foreseen.

^ssc5 illus, 1 table, 14 ref

003538   Amirthalingam R;Shaikh H;Anita T;Poonguzhali A;Manohar P;Khatak H S (Physics Dep, Government Arts College, Cuddalore, Tamil Nadu) : Effect of high temperature ageing on the corrosion behaviour of nitrogen-added AISI type 316L stainless steel. Trans Indian Inst Metals 2006, 59(2), 271-82.

Deals with the effect of microstructural changes that occur on high temperature aging of AISI type 316LN stainless steel (SS) on its corrosion behaviour. Aging at 923, 973 and 1023 K for time durations up to 1000 h caused the following changes in the microstructure of type 316LN SS: (a) precipitation of Cr₂N, carbide/carbonitride (C/CN) and σ-phase at the austenite grain boundaries, (b) changes in the amount, size and shape of σ-phase, (c) depletion of solid solution strengtheners, such as Cr, Mo, C, N, in the austenite matrix. Corrosion behaviour of annealed and aged base metals was studied in acidified 1M NaCI solution by electrochemical polarisation technique. Copious σ-phase precipitation on aging for 1000 h at 1023 K caused significant rise in critical current density (i_CCD), while at other temperature-time combinations, the changes in i_CCD were minimum. Aging caused the critical pitting potential (E) and repassivation potential (E_rep) to decrease; the decrease being maximum on aging for 1000 h at 1023 K. The Electrochemical Potentiokinetic Reactivation (EPR) tests in 0.01M KSCN + 0.5M H₂SO₄ solution showed high intergranular depletion of chromium and molybdenum on aging at 923 K and no depletion of these elements at other temperatures.

10 illus, 63 ref

003537   Aluru R;Sofyan N I;Gale W F (Materials Research and Education Center, Auburn University, Auburn, AL 36830, USA, Email: alurusc@auburn.edu) : Microstructural development and mechanical property relationships in wide-gap transient liquid phase bonding of single crystal to polycrystalline nickel-base superalloys. Trans Indian Inst Metals 2006, 59(2), 185-91.

Investigates the microstructure-mechanical property relationships in wide gap transient liquid phase (TLP) bonds, between' the single crystal nickel-base superalloy CMSX-4 and two polycrystalline superalloys, IN 738 and IN 939, using wide-gap style composite interlayers of Niflex-110 and Niflex-115, in comparison with conventional BNi-3 foils. Composite interlayers resulted in the suppression of bondline boride formation. Results from shear testing and fractography indicated that ductile shear failure occurred along the bondline and I that the extent of formation of g' on the bondline was the dominant factor in the determination of room-temperature shear strength of the bonds.

7 illus, 11 ref

003536   Agrawal A;Joshi R C;Radhakrishna M (NO, Indian Institute of Information Technology, Allahabad-211 011) : Real-time photorealistic visualisation of large-scale multiresolution terrain models. Def Sci J 2007, 57(1), 149-62.

Describes a novel approach for objects and terrain visualization by combination of two algorithms, one for terrain data and the other for objects. The terrain rendering is accomplished by an efficient dynamic multiresolution view-dependent level-of-detail mesh simplification algorithm. It is augmented with out-of-core visualisation of large-height geometry and photo texture terrain data populated with 3-D/2-D static objects as well as vector overlays without extensive memory load. The proposed methodology provides interactive frame rates on a general-purpose desktop PC with OpenGL-enabled graphics hardware. The software TREND has been successfully tested on different real-world height maps and satellite phototextures of sizes up to 16K * 16K coupled with thousands of static objects and polyline vector overlays.

10 illus, 2 tables, 25 ref

003535   Acharya R S;Naik S D (NO, Vishwakarma Institute of Information Technology, Pune-411 048) : Modelling of shockwave force and the effect during sabot discrd process. Def Sci J 2007, 57(5), 677-90.

Dynamical motion of a FSAPDS projectile is affected due to the propellant gas force, aerodynamic, gravity along with mechanical force, and shockwave forces. In the sabot opening process, the mechanical action takes place and the sabot gets separated due to the shockwave force. In external mechanical action of sabot separation, the maximum stretch of the spring defines the end of third phase of motion. The motion of the projectile and its stability during this phase has been presented. The time delay in the sabot opening affects the stability of the projectile is discussed with the help of modified stability parameter.

8 illus, 2 tables, 14 ref

003534   Achary G;Sachin H P;Arthoba Naik Y;Venkatesha T V (PG Studies and Research In Chemistry Dep, School of Chemical Sciences, Kuvempu Univ, Shankaraghatta-577 451, Email: drarthoba@yahoo.co.in) : Effect of a new condensation product on electrodeposition of zinc from a non-cyanide bath. Bull Mater Sci 2007, 30(3), 219-24.

Zinc electrodeposition from sulphate chloride bath was carried out in presence of condensation product formed between chitosan and veratraldehyde. The bath constituents and operating parameters such as pH, temperature and current density were optimized through Hull cell experiments. Current effieiency and throwing power were measured. Polarization study revealed high shift of potential towards negative direction in the presence of addition agents. Corrosion resistance test revealed good protection of base metal by zinc coating obtained from developed electrolyte. SEM photomicrographs showed fine-grained deposit in the presence of condensation product. The IR spectrum of the deposit showed inclusion of the condensation product during electroplating. The consumption of brightener in the lab scale was 5 mLL^-1 for 1000 amp-h.

4 illus, 3 tabels, 15 ref

002601   Wadhwa H;Bhatt D L (NO, , Tehri Hydro Development Corporation Ltd.) : Environmental issues of Tehri hydro project-A unique case of environment consciousness. Wat Energy int 2007, 64(1), 421-34.

Describes how the environmental issues have been resolved in Tehri Project, that in addition to its significant future contribution in the field of energy generation, it is also upgrading the surrounding environmental conditions and will also improve quality of life and provide employment opportunities. The paper highlights: Impact on ecology, monuments, seismicity.,Involvement of resettlement & rehabilitation., Catchment area treatment, Flora & Fauna, Impact on human health etc.

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002600   Viswanath P R (Experimental Aerodynamics Div, National Aerospace Laboratories, Bangalore, Email: p.r.viswanath@gmail.com) : Some thoughts on separation control strategies. Sadhana 2007, 32(1-2), 83-92.

Brief review is presented of three broad strategies for separation control: these include methods that involve energization of the boundary layer upstream of separation, those that involve altering the bubble flow or dead air zone, and those that may influence the shear layer reattachment directly. Examples from recent research in our laboratories are reviewed and it is suggested that direct manipulation of the reattachment process could lead to effective control/management.

7 illus, 22 ref

002599   Vishwanatha Rao A N;Ramesh O N (NO, Gas Turbine Research Establishment, Bangalore) : The dynamics of surge in compression systems. Sadhana 2007, 32(1-2), 43-9.

In air-compression systems, instabilities occur during operation close to their peak pressure-rise capability. However, the peak efficiency of a compression . system lies close to this region of instability. A surge is a violent mode of instability where there is total breakdown of flow in the system and pressure-rise capability is lost drastically. Generally, all compression systems operate with a margin defined as the 'surge margin', and, consequently, system operational efficiency is lower. It is of interest to study compression-system surge to understand its dynamics in order to operate compression systems close to the instability for achieving high efficiency safely without encountering surge. Unsteady pressure data from a compression system, captured during surge oscillations, reveal many aspects of flow physics and are analysed to understand the surge dynamics of the system. A set of controlled experiments was conducted with a simple desktop experimental test set-up and essential aspects of surge dynamics have been characterised.

6 illus, 5 ref

002598   Vishnoi R K;Singh A K (NO, , Tehri Hydro Development Corporation Ltd.) : Diversion flood and river diversion scheme. Wat Energy int 2007, 64(1), 108-11.

Presents an account of river diversion scheme as adopted and a brief account of the studies carried out for fixing the height of cofferdam and proposed sequence of closure of diversion funnels.

1 table, ref

002597   Vishnoi R K;Jindal H K (NO, , Tehri Hydro Development Corporation Ltd.) : Hydraulic model studies for spillway structures. Wat Energy int 2007, 64(1), 282-8.

Design of all the spillways has been optimized and tested on physical models built on the similarity principles. Almost all the hydraulic model studies have been carried out at Irrigation Research Institute, Roorkee.

5 tables, ref

002596   Vishnoi R K;Govil R (NO, , Tehri Hydro Development Corporation Ltd.) : Sedimentation and life of the reservoir. Wat Energy int 2007, 64(1), 99-107.

Deals with the estimation of the reservoir siltation rate, reduction in the live storage of reservoir with passage of time and prediction of useful life of the reservoir on the basis of observed silt data. The analysis of observed silt data for estimation of above parameters has been made in accordance with CBIP Technical Report No. 19 of year 1980 and Technical guidelines of USBR on Reservoir Sedimentation.

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002595   Vishnoi R K;Goel S;Sandeep Kumar (NO, , Tehri Hydro Development Corporation Ltd.) : An overview of koteshwar hydro electric project. Wat Energy int 2007, 64(1), 462-5.

Koteshwar Hydro Electric Project is an integral part of Tehri Hydro Power Complex comprising of Tehri Dam & HPP (1000 MW), Tehri PSP (1000 MW) and Koteshwar HEP (400 MW) to develop hydroelectric potential of river Bhagirathi. The Koteshwar reservoir shall serve for re-regulation of the flow to be released from the Tehri reservoir and also act as a lower reservoir of Tehri PSP for pumping mode. This will facilitate the functioning of Tehri Hydro Power Complex as a major peaking station in Northern grid, having installed capacity of 2400MW. The paper presents an overview of the project.

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002594   Vishnoi R K;Chauhan S K (NO, , Tehri Hydro Development Corporation Ltd.) : Sustainable development - a case study of dam project. Wat Energy int 2007, 64(1), 14-19.

In today's world of technological revolution, every citizen of India has the responsibility to look into the aspects of environmental changes due to activity being performed by him. Models of sustainability can only be achieved if today's generation is conscious towards the rights of the future generation to come. Government has launched an extensive development programme to provide clean power to all citizens by 2012 ensuring the sustainable economic growth. The rate of high dams in providing the energy has been well reorganised by the Govt. Although, developmental activity like construction of high dam has its positive as well as negative impacts but; proper planning & proficiency of the projects can mitigate the negative impacts during implementation of the project. Tehri Dam Project, the highest earth and rock-filled dam in India, has been executed for all-round development in the region ensuring negligible damage to the surrounding environment. A host of measures have been taken while developing the Tehri Dam Project so as to make it a sustainable development.

1 table, ref

002593   Venukumar B;Reddy K P J (Aerospace Engineering Dep, Indian Institute of Science, Bangalore-560 012, Email: laser@aero.iisc.ernet.in) : Experimental investigation of drag reduction by forward facing high speed gas jet for a larg angle blunt come at Ma ch 8. Sadhana 2007, 32(1-2), 123-31.

Substantial aerodynamic drag, while flying at hypersonic Mach number, due to the presence of strong standing shock wave ahead of a large-angle blunt-cone configuration, is a matter of great design concern. Preliminary experimental results for the drag reduction by a forward-facing supersonic air jet for a 60ø apex-angle blunt cone at a flow Mach number of 8 are presented. The measurements are carried out using an accelerometer-based balance system in the hypersonic shock tunnel HST2 of the Indian Institute of Science, Bangalore. About 29% reduction in the drag coefficient has been observed with the injection of a supersonic gas jet.

6 illus, 1 table, 11 ref

002592   Vasudevan B;Padbidri S;Chandra Kishore M (Aerospace Engineering Dep, Indian Institute of Science (IISc), Bangalore-560 012, Email: vasu,padbidri@aero.iisc.ernet.in) : Flow diagnostics using fibre optics. Sadhana 2007, 32(1-2), 7-18.

Research in the area of flow diagnostics using fibre-optics started in our laboratory in early 1998. The first-ever multi-component wind tunnel balance, in the world, working with fibre-optic sensors was built and demonstrated in 1999 Since then, several new applications of the technique in the area of fluid dynamic load measurements have been tried successfully. Very recently, fibre-optic sensors have been effectively used for underwater applications, where conventional measurements are relatively very difficult. Since, different physical perturbations affect optical power flowing in a fibre in different ways, unique signatures can be obtained which allow absolute or relative measurement of the incident disturbances. Immunity to electromagnetic or radio frequency interference, high temperature capability, low fatigue, high sensitivity, small size, good corrosion resistance and the capability to embed sensors within the model surface are some of the very attractive features of fibre-optic based instrumentation systems. Discribes the results of experiments of aerodyrlamic load measurements at hypersonic speed (Mach 8-35 and 7-0) and studies carried out recently in a water tunnel over a lifting hypersonic vehicle with a 2-component fibre-optic strain-gauge balance.

17 illus, 5 ref

002591   Tiwari R P;Gupta M K;Srivastava R K (Civil Engng Dep, M.N.N.I.T., Allahabad) : Laboratory studies on surfactant enhanced remediation of engine oil contaminated soils. Indian Geotech J 2006, 36(4), 287-98.

Soil contamination is one of the most widespread and serious environmental problems confronting both the industrialized as well as developing nations like India. Different contaminants have different physicochemical properties, which influence the geo-chemical reactions induced in the soil and may bring about adverse changes in the engineering behaviour of soils. With this proposition in view, an experimental investigation was undertaken to evaluate (i) the effects of waste engine oil (W.E.O.) on the geotechnical properties of soils, and (ii) as. to what extent a cleaning agent such as surfactant could obviate the effects of contaminant. Two types of soils, viz. clay with low compressibility (CL) and clay with high compressibility (CH) were mixed with varying proportions of waste engine-oil and index properties as well as important engineering properties were evaluated before and after contamination. A nonionic surfactant was used at different strengths for varying soil-contaminant ratios to study as to what extent and at what strength the cleaning agent could restore the properties of soils possessed by them in their uncontaminated state. Results show that the soil properties could undergo drastic changes in presence of the studied contaminant and the quantity of surfactant could be optimized to retrieve the original soil properties to a large extent.

6 illus, 5 tables, 15 ref

002590   Srinivasan S;Ranganathan S (School of Humanities, National Institute of Advanced Studies, Bangalore, Email: rangu@met.iisc.ernet.in) : Nonferrous materials heritage of mankind. Trans Indian Inst Metals 2006, 59(6), 829-46.

Narrates a brief history of the nonferrous metals in antiquity. The metals include gold, copper, silver, lead, tin, mercury and tin. A few alloys of antiquity, in particular electrum, tumbaga, arsenical and tin bronzes, are also described. Further silk and diamond have been added in view of the prominence they have enjoyed since antiquity. The historical development of these materials is viewed against the geographic landscape of continental Africa, Asia, Europe and America. The transition from the predominant use of one material to that of another material is discussed from technical and socio-cultural perspectives. The anticipation of modern science in ancient metallurgical practice is a recurrent theme.

10 illus, 3 tables, 40 ref

002589   Somayajulu M R;Gautam G K;Subhananda Rao A (High Energy Materials Res Lab, , Pune-411 021) : Stabilisation of red phosphorus to prevent moisture absorption and suppression of phosphine release. Def Sci J 2007, 57(6), 817-24.

Red phosphorus (RP) is an essential ingredient to generate smoke for multi-spectral obscuration and is receiving wide attention throughout the world for military applications. However, oxidation of phosphorus occurs in moist air resulting in the formation of various phosphorus acids and subsequently the evolution of the toxic gas, phosphine (PH₃), even in the sealed systems. Entrapped moisture leads to deterioration of the stores. The commercial-RP at ambient temperature and 95 per cent RH conditions indicates 15 per cent moisture absorption and 13 per cent acidity development with the generation of more than 100 ppm of phosphine gas. Efforts were made to overcome this problem by suppressing acid formation. The technology adopted was: (i) use of stabiliser, and (ii) doping stabiliser-coated particles with polymeric substance. The aim to use metal oxide as stabiliser was to neutralise the phosphorus acids, which are catalysing the phosphine generation. MgO due to its basic nature seems to be faster than amphoteric A1₂0₃, in removing the acid from site of reaction, thus suppressing the phosphine release effectively. Though MgC0₃ as stabiliser suppresses moisture absorption and acidity development, phosphine release is not controlled effectively. Study of RP coated with these materials independently and monitoring them at different RH conditions indicated superiority of MgO in. suppressing acidity and phosphine formation.

7 illus, 1 table, 11 ref

002588   Sinha R K;Shekhar H;Subhananda Rao A; Haridwar Singh (High Engergy Materials Res Lab, , Pune-411 021) : Modelling of DMNB content for marked plastic explosives. Def Sci J 2007, 57(6), 811-15.

2, 3-dimethyl-2,3-dinitrobutane (DMNB) has been internationally accepted as an additive for' the purpose of marking, as it has desired vapour pressure for reliable detection. It is reported to be compatible with known explosive formulations and has a good shelf life. Explosive compositions with DMNB as marking agent can be detected in the temperature range -20°C to + 50°C. This paper describes modelling for quantifying activation energy for depletion of DMNB in the marked explosives, period for definite detection of the marked explosives and optimum initial concentration needed for the detection of DMNB content in the marked plastic explosives.

^ssc2 illus, 4 ref

002587   Singh R;Mandal P K;Singh A K;Kumar R;Sahendra Ram;Jena S K (CMRI, , Dhanbad) : Encountering induced horizontal stress during simultaneous depillaring of thick and contiguous section below hilly terrain. MGMI Trans 2005, 102(1-2), 37-61.

After successful simultaneous depillaring of most of the panels of thick and contiguous sections. of the Zero seam at Bartunga Hill mine of Chirimiri Area, SECL under fast change in cover below hill cap, last few panels of the mine encountered strata control problems. Underground instrumentation and observations showed that the last phase depillaring of the property near free surface of the hill slope becomes challenging due to shearing of overlying strata along weak and incompetent layers. A simple study on simulated model also supported occurrence of the problem due to poor confinement of the rock mass. The shearing resulted high value of horizontal mining induced stress, which caused failure of the roof strata. Field and laboratory studies were conducted to identify the main horizons of lateral movement and, accordingly, a management plan for the induced horizontal stress was successfully executed in both, top and bottom sections of the seam, to overcome the strata control problem of the depillaring. The efficacy of the adopted strata management plan was visualized through field instrumentation.

13 illus, 5 tables, 9 ref

002586   Shukla S K;Prasad G M;Routela T S (NO, , Tehri Hydro Development Corporation Ltd.) : Stabilization of TRT outlet area of Tehri HPP - an effective approach. Wat Energy int 2007, 64(1), 335-42.

Described the slope stability analysis, remedial measures adopted to arrest movement of the unstable slopes in the area of tailrace tunnel outlet works and the method of construction of tailrace portals without causing any instability to hill slopes, monitoring the behaviour of slope and the retaining cellular structures etc.

5 illus, ref

002585   Sharma S;Jain R C;Bhadauria S S (School of Information Technol, Rajiv Gandhi Technolical Univ, Bhopal) : Performance analysis of wireless Ad Hoc network routing protocol. Ultra Scient phys Sci 2006, 18(2), 231-46.

An ad hoc network is a collection of wireless mobile nodes dynamically forming a temporary network without the use of any existing network infraª structure or centralized administration. Due to the limited transmission range of wireless network interfaces, multiple network "hops" may be needed for one node to exchange data with another across the network. In recent years, a variety of new routing protocols targeted specifically at this environment have been developed, but little performance information on each protocol an o realistic performance comparison between them is available. Presents the review results of a detailed packet-level comparing four multi-ho wireless ad hoc network routing protocols that cover a range of design choices: DSDV, TORA, DSR, and AODV.

4 illus, 5 tables, 23 ref

002584   Sharma S D;Pant R R (Aerospace Engineering Dep, Indian Institute of Technology-Bombay, Mumbai-400 076, Email: sd.sharma@iitb.ac.in) : On wake response to asymmetric blowing in spurts from a blunt trailing edge. Sadhana 2007, 32(1-2), 111-22.

Technique has experimentally been evolved with the aim to control the unsteady wake dominated by periodic vortex-shedding. The technique uses pulsating surface blowing that is applied asymmetrically just before separation from the blunt trailing edge of a thick aerofoil model. Thus, momentum is injected in spurts in only one of the two separated shear layers. The control parameters are the mass flow rate and the forcing frequency of the pulsating blowing. The technique is particularly effective in suppressing the vortex-shedding when the blowing is moderate and the forcing frequency is twice the natural vortex-shedding frequency. As a consequence of injecting momentum in spurts, there is a significant saving in mass flow required to achieve a condition of the momentumless wake. In spite of the initial conditions being strongly asymmetric, the flow pattern in the wake was observed to quickly assume a remarkable symmetry.

13 illus, 10 ref

002583   Sharma S C;Vishnoi R K (NO, , Tehri Hydro Development Corporation Ltd.) : Unique design features and innovative measures implemented in chute & shaft spillways of tehri dam. Wat Energy int 2007, 64(1), 259-71.

Deals with the innovative techniques adopted during finalization of spillway layout, hydraulic model studies in evolving the efficient hydraulic design of spillway structures, energy dissipation measures adopted and the innovation done for guarding the structures against the cavitation and abrasion erosion. The experience during the design and construction of the shaft spillways at Tehri project has been technologically unique in respect of the protection measures for cavitation and abrasion.

7 illus, 13 ref

002582   Sharma S C;Vishnoi R K (NO, , Tehri Hydro Development Corporation Ltd.) : Design measures adopted during execution of shaft spillways. Wat Energy int 2007, 64(1), 237-47.

At Tehri Project, the spillways have been designed for a Probable Maximum Flood (PMF) of 15540 cumecs computed for a return frequency of 1 in 10,000 years. The routed flow through the designed structures is 13200 cumecs at the maximum level of the reservoir. Tehri spillway structures consist of a number of unique features, which are being implemented in India for the first time. The spillway system comprises of a chute spillway with three bays along with four shaft spillways designed for a head of 220 m. The shaft spillways utilize the existing four diversion tunnels which would have otherwise become redundant after plugging of the tunnels at the end of construction period. The experience during the construction of these shaft spillways has been methodologically and technologically unique as the design measures adopted during the execution proved to be successful in completing the activities. The paper outlines few suchlexperiences along with the design measures applied.

8 illus, 6 ref

002581   Sharma S C;Singh S;Routela T S;Chauhan S K (NO, , Tehri Hydro Development Corporation Ltd.) : Design of steel liners for Tehri HPP. Wat Energy int 2007, 64(1), 303-8.

Describes the design criteria adopted for internal and external pressures, rock participations in resisting the internal pressure and additional precautions being taken during fabrication and erection of steel liners.

3 illus, 5 ref

002580   Sharma S C;Prasad G M;Singh S;Jain A (NO, , Tehri Hydro Development Corporation Ltd.) : Drainage arrangements of underground works of Tehri hydro power plant. Wat Energy int 2007, 64(1), 313-17.

For Tehri Hydro Power Plant seepage studies of left bank hill mass housing the units and transformers were performed to optimize the drainage arrangements. Paper describes such arrangements.

2 illus, 1 table, 2 ref

002579   Sharma S C;Prasad G M;Ghosh K K (NO, , Tehri Hydro Development Corporation Ltd.) : Instrumentation scheme. Wat Energy int 2007, 64(1), 194-203.

Tehri dam is a 260.5m high earth & rockfill dam constructed across the mythical river Bhagirathi in the lower Himalayas region of India. Location of the dam falls in a region of high seismicity. In such region, site for the dam was selected in a narrow gorge on various considerations. In order to monitor the behaviour of the dam both during construction and operation period, and to verify the assumptions made during the design of its structure, an elaborate scheme of instrumentation has been provided in the body of the dam & its foundation. Two inspection galleries have also been provided through the body of dam core to visually inspect the body of dam during the operation period of the project. In addition to the above, seismic instrumentation for studying the strong motion and micro seismic events of the Tehri region has also been provided.

6 illus, 2 tables, 4 ref

002578   Sharma S C;Prasad G M;Ghosh K K (NO, , Tehri Hydro Development Corporation Ltd.) : Seismic aspects of dam. Wat Energy int 2007, 64(1), 180-4.

3 illus, 1 table, 8 ref

002577   Sharma R K;Prasad G M;Singh S;Routela T S (NO, , Tehri Hydro Development Corporation Ltd.) : Design of underground power house chaverns of Tehri HPP. Wat Energy int 2007, 64(1), 289-96.

Describes the methodology of the design of large underground caverns. The design process involved continuous evaluation of rock parameters, detailed 2Dand 3D numerical modelling and monitoring program. The paper briefly also describes the Tehri power house complex, its geological and geotechnical assessment, stabilization measures adopted, numerical modelling coupled with instrumentation scheme etc.

4 illus, 1 table, ref

002576   Sharma R K;Mann P P S;Vishnoi R K (NO, , Tehri Hydro Development Corporation Ltd.) : Shaft spillways effective execution based on analytical approach. Wat Energy int 2007, 64(1), 248-58.

Shaft spillways utilize the existing four diversion tunnels which would have otherwise become redundant after plugging of the tunnels at the end of construction period. The experience during the construction of these shaft spillways has been methodologically and technologically unique as the design measures adopted during the execution proved to be successful in completing the activities. The paper outlines few such experiences along with the design measures applied.

12 illus, 4 ref

002575   Sharma R K;Mann P P S;Bishnoi A (NO, , Tehri Hydro Development Corporation Ltd.) : Effective planning for hauling fill materials. Wat Energy int 2007, 64(1), 206-7.

9 illus, 5 tables, 2 ref

002574   Sharma K S (NO, , Tehri Hydro Development Corporation Ltd.) : Inimitable experiences during construction of Tehri dam project. Wat Energy int 2007, 64(1), 456-7.

ref

002573   Shanker K;Basudhar P K;Patra N R (Civil Engng Dep, .I.I.T., Kanpur-208 016, Email: shanker@iitk.ac.in) : Uplift capacity of single piles embedded in sand. Indian Geotech J 2006, 36(4), 334-47.

Pertains to the development of a semi-empirical model assuming a curved failure surface for predicting the uplift capacity of piles embedded in sand. The method takes into consideration of various soil properties and surface characteristics of piles such as angle of friction (φ), and unit mughth (γ), soil-pile friction angle (δ), length (L) and diameter (d) of the pile which have direct influence on the uplift capacity of the pile. A comparative assessment of the ultimate uplift capacity of piles predicted by using the proposed theory and some of the available theories are made with respect to each other and also with reference to the measured values obtained from model tests in the laboratory. For this purpose, experimental data have been collected from the literature and also from model tests conducted as a part of the investigation. The study shows that the proposed model has an excellent potential in predicting the uplift capacity of piles embedded in sand that is consistent with experimental results.

8 illus, 3 tables, 20 ref

002572   Shah A L;Narang J L;Singh S;Jain A (NO, , Tehri Hydro Development Corporation Ltd.) : Slope stabilisation of intake area of Tehri HPP and PSP. Wat Energy int 2007, 64(1), 327-34.

Described the geological and geotechnical assessment of the area and the stabilization measures adopted on the slopes for preventing failures during reservoir operations.

3 illus, 3 ref

002571   Shah A L;Mann P P S;Bharaj H L;Singh J (NO, , Tehri Hydro Development Corporation Ltd.) : Quality control aspects of Tehri dam project. Wat Energy int 2007, 64(1), 408-20.

5 illus, 14 tables, 1 ref

002570   Sen P K;Veeravalli S V;Carpenter P W;Joshi G; Josan P S (Applied Mechanics Dep, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi-110 016, Email: pksen,svrvalli@am.iitd.ernet.in) : Organised structures in wall turbulence as deduced from stability theory-based methods. Sadhana 2007, 32(1-2), 51-64.

Explored the relevance of hydrodynamic stability theory to fully developed turbulent wall flows. Using an extended Orr-Sommerfeld Equation, based on an anisotropic eddy-viscosity model, it was shown that there exists a wide range of unstable wave numbers (wall modes), which mimic some of the key features of turbulent wall flows. Presents experimental confirmation for the same. There is good qualitative and quantitative agreement between theory and experiment. Once the dominant coherent structure is obtained from stability theory, control of turbulence would be the next logical step. As shown, the use of a compliant wall shows considerable promise and also present some theoretical work for bypass transition (Klebanoff/K-modes), wherein the receptivity of a laminar boundary layer to a vortex sheet in the freestream has been studied. Further, it is shown that triadic interaction between K-modes, 2D TS waves and 3D TS waves can lead to rapid algebraic growth. A similar mechanism seems to carry over to! inner wall structures in wall turbulence and perhaps this is the "root cause" for sustenance of turbulence.

11 illus, 18 ref

002569   Sen N;Sardar M K;Ghosh M;Gupta S K (R&D Centre, SAIL, Ranchi-834 002) : Maximisation of liquid inclusions in wheel steel. Steel India 2007, 29(2), 110-14.

Analysis has being carried out on Wheel Steel samples to determine the nature and the quantities of inclusion using Quantimet and EPMA. High levels of non-metallic inclusions of approximately 0.5% have been found. A model has been developed for the computation of steel chemistry and dissolved oxygen which are in equilibrium with the inclusions. Equations for estimation of activities of SiO₂, MnO and A1₂O₃ have been developed. The output from the model can be used to decide the level of Manganese and Silicon in equilibrium with particular oxygen content in metal leading to required inclusion chemistry.

2 illus, 4 tables, 20 ref

002568   Satheesh S K;Krishna Moorthy K (Centre for Atmospheric and Oceanic Sci, Indian Inst of Sci, Bangalore-560 012, Email: satheesh@caos.iisc,ernet.in) : Multi-angle polarization imager: a satellite sensor for studies of continental aerosols. Curr Sci 2007, 92(2), 174-6.

Knowledge of aerosol radiative forcing over land is essential to answer crucial questions related to climate change. Retrieval of aerosol properties over land is complicated due to irregular terrain characteristics and high surface reflection. The retrieval of algorithms used in conventional satellite sensors for continental regions is not completely free from the high reflectance effect and hence leads to large uncertainties in the retrieved parameters. Proposes a dedicated satellite sensor namely multi-angle polarization imager (MAPI). The main characteristic of MAPI is multi-spectral and multi-angle measurements of polarized comªponents of reflected radiation from the Earth. The proposed sensor has capability of aerosol retrieval over land. The sensor also has the ability to discriminate dust aerosols (which is the major natural aerosol over land) from other aerosols (using infrared radiance). This is the first step towards separating natural and anthropogenic aerosols, which is needed for the scientific community at large.

3 illus, 10 ref

002567   Sameen A;Govindarajan R (Engineering Mechanics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore-560 064, Email: asameen@gmail.com) : Some indications from instability results about the effectiveness of wall heating as a control option for channel flow. Sadhana 2007, 32(1-2), 65-81.

Review of some off recent work on the effect of wall heating on the stability of laminar flow in a channel has been presented. The summary of the results, some of them unexpected, is as follows. Viscosity stratification has very lit-tle effect on transient growth, whereas it results in linear mode stabilising or desta-bilising by an order of magnitude. It has hitherto been accepted that heat diffusivity does not affect stability. This is however true only for linear instability, transient growth is affected by an order of magnitude. Unusually, the growth is spanwise-independent and not in the form of streamwise vortices. It is also shown that flow is destabilised by secondary modes as the viscosity ratio increases. However, the viscosity ratio has no role in the selection of the pattern of A vortices.

16 illus, 35 ref

002566   Sai R S T;Jain A K (NO, , Tehri Hydro Development Corporation Ltd.) : Financial aspects of Tehri dam project. Wat Energy int 2007, 64(1), 46-9.

3 tables, ref