004845   Harman International Industries (NO, , 1718 West Mishawaka Road, P.O.Box 1000, Elkhart, IN 46515-1000 USA) : A switch mode power suplly for a bridged linear amplifier. 0000, (NULL), (NULL).

004844   Gottlieb Binder Gmbh & Co (NO, , Bahnhofstr. 19, 71088 Holzgerlingen, Germany) : An attachment system for a vehicle seat. 0000, (NULL), (NULL).

004843   Gec Alsthom Delas (NO, , 12-14 rue d Alsace, 92300 Levallois-perret, France) : A bundle of tubes for a steam condenser. 0000, (NULL), (NULL).

004842   Evergreen Solar, Inc (NO, , 211, Secpmd Avenue, Waltham, Massachusetts 02154, USA) : A laminated solar cell module with improved backskin and method for its manufacsture. 0000, (NULL), (NULL).

004841   Eun Un-Kee (NO, , 329-1, Gwangjang Dong, Gwangjin-Gu, Seoul, Republic of Korea) : Vending machine. 0000, (NULL), (NULL).

004840   Ensign-Bickford Co (NO, , 660 Hopmeadow Street, Simsbury, Connecticut 06070, USA) : Delay circuit for hybrid electronic detonator and a transducer circuit assembly comprising the same. 0000, (NULL), (NULL).

004839   Emitec Gesellschaft Fur Emissionstechnologie MBM (NO, , Hauptstrasse 150, D-53707 Lohmar, Germany) : An extruded honeycomb assembly. 0000, (NULL), (NULL).

004838   Eaton Corp (NO, , 1111 Superior Avenue, Cleveland, Ohio 44114, USA) : An improved clutch disc device and a method of producing such a device. 0000, (NULL), (NULL).

004837   Dixit P P (NO, , E1142, Lajpat Nagar, New Delhi-110 024) : An anti theft electronic device for automobiles. 0000, (NULL), (NULL).

004836   Daewoo Electronics Corp (NO, , 686 Ahyeon-Dong, Mapo-Gu, Seoul, Korea) : Washing machine having a spraying nozzle assembly. 0000, (NULL), (NULL).

004835   Daewoo Electronics Co. Ltd (NO, , 541, 5-Ga, Namdaemoon-Ro, Jung-Gu, Seoul-100 095, Republic of Korea) : Cassette loading and unloading device for use in a video cassette recorder. 0000, (NULL), (NULL).

004834   Council of Scientific & Industrial Research (NO, , Rafi Marg, New Delhi-110 001) : An improved isoelectric focusing unit. 0000, (NULL), (NULL).

004833   Council of Scientific & Industrial Research (NO, , Rafi Marg, New Delhi-110 001) : A device useful for transmitting standard time over a telephone network. 0000, (NULL), (NULL).

004832   Comsat Corp (NO, , 6560, Rock Spring Drive, Bethesda, Md 20817, USA) : A method of achieving least cost routing in a mobile satellite communication system. 0000, (NULL), (NULL).

004831   Chr Mayr Gmbh & Co. Kg (NO, , Eichenstrabe 1, 87665 Mauerstetten, Germany) : Torsionally rigid, play-free, flexible metal bellows-type coupling for the torque-transmissive connection of two shafts. 0000, (NULL), (NULL).

004830   Carrier Corp (NO, , P O Box 4800, Syracuse, New York 13221, USA) : Method and apparatus for torque control to regulate power requirement at start up. 0000, (NULL), (NULL).

004829   Bwg Butzbacher Weichenbau Gmbh (NO, , Wetzlarer Strasse 101, 35510 Butzbach, Germany) : Joining process for producing a railroad track part. 0000, (NULL), (NULL).

004828   Bundesdruckerei Gmbh (NO, , Oranienstrasse 91, D-10958 Berlin, Germany) : A security element for documents and a method for its fabrication. 0000, (NULL), (NULL).

004827   Bharat Heavy Electricals Ltd (NO, , BHEL House, Siri Fort, New Delhi-110 049) : A switched reluctance motor controller. 0000, (NULL), (NULL).

004826   Bharat Heavy Electricals Ltd (NO, , BHEL House, Siri Fort, New Delhi-110 049) : An improved ring lubricated combined journal and thrust bearing. 0000, (NULL), (NULL).

004825   Bharat Heavy Electricals Ltd (NO, , BHEL House, Siri Fort, New Delhi-110 049) : A fire extinguishing device for gas blow-outs. 0000, (NULL), (NULL).

004824   Autorobot Finland Oy (NO, , Yrittajantie 23, Fin-70150 Kuopio, Finland) : A device and method for alignment of a vehicle. 0000, (NULL), (NULL).

004823   Arraycomm, Inc (NO, , 125 Nicholson Lane, San Jose, California 95134, USA) : A wireless system for calculating uplinksignals transmitted from a plurality of remoteterminals using a common uplink channel. 0000, (NULL), (NULL).

004822   Amsted Industries Incorporated (NO, , 205 North Michigan Avenue, 44th Floor, Boulevard Towers South, Chicago, Illinosis 60601, USA) : An improved lightweight railcar truct sideframe. 0000, (NULL), (NULL).

004821   Alfa Laval Moatti Snc (NO, , Z.I. Le Chene Sorcier - CD 161 - 78340 Les Clayes Sous Bois, France) : A device for treating a fluid. 0000, (NULL), (NULL).

004820   Venugopala Rao K;Someswara Rao N (Shiva Analyticals (India) Limited, , Plots 24 D (P) and 34 D, KIADB Industrial Area, Hoskote 562 114 Bangalore Rural North) : Assessment of quality of harbour waters in major ports of India: part III - Madras (Chennai) and tuticorin ports. Indian J envir Prot 2003, 23(9), 1025-32.

The harbour waters of Madras and Tuticorin ports were assessed for their quality. The polluted conditions in the harbour waters of Madras port was found to be mainly due to the Coom river waters, which brings the industrial effluents, city's sewage, entering the open sea very close to the harbour. Significant positive correlations between zinc, copper and cadmium and also between manganese and iron for the harbour waters of Madras port sugested the existence of common sources for these pollutants. The harbour waters of Tuticorin port are less polluted compared to that of Madras port. The influence of industrial effluents and the polluted fishing harbour waters on the harbour water quality of Tuticorin port is less because of the unfavourable average littoral drift at Tuticorin port.

2 illus, 2 tables, 8 ref

004819   Vairagade D M;Juneja H D;Jadhav R T;Paliwal L J (Nagpur University, Department of Chemistry, Nagpur 440 010) : Impact of ash bund of thermal power station on fluorides in ground water. Indian J envir Prot 2003, 23(11), 1223-9.

In Koradi Thermal Power Station, 21000MT of coal is burnt everyday, producing 9100MT of coal ash which pollutes the environment. Out of the total ash generated, 910MT (containing 2204.5 mg/L fluoride), is released into the atmosphere as flyash daily. The remaining 8190 MT ash containing on an average of 1746 mg/L fluoride is dispersed on land surface in the form of slurry. The slurry containing 8190 MT ash and 17,571mL water is finally stored in ash bunds. The supernatent water is charged into the local drainage system. Koradi Thermal Power Station, thus, pollutes the atmosphere everyday with 910 MT flyash containing 1443kg fluoride. 17,571mL effluent from ash bunds pollutes local surface water with 13, 148kg fluoride/day. The Ca²⁺ and SO²₄ rich ash bund water fortunately critically decreases CaF₂ solubility. Possibility of significantly high fluoride content due to coal ash pollution of similar composition in water, poor in Ca²⁺ and SO²₄ content is strongly indicated. Ground water samples were collected and analysed for fluoride content and other quality parameters. Fluoride content (0.4 to 2.8 mg/L) was found to be higher than that of the permissible levels recommended by World Health Organisation (0.5mg/L) and ICMR (1.0mg/L).

4 illus, 4 tables, 16 ref

004818   Thakur P;Chakravarty S;Maity S;Bhattacharjee S;Gupta K K (Applied Chemistry and Corrosion Division, National Metallurgical Laboratory, Jamshedpur 831 007) : A study on the adsorption of Cr(VI) on a synthetically prepared Zn-Al-Cl layered double hydroxide (LDH). Metals Mater Process 2004, 16(2-3), 339-50.

A Zn-Al-Cl layered double hydroxide (LDH) has been synthetically prepared. The LDH has been characterised and extensively studied with reference to Cr(VI) adsorption in aqueous solutions. The chemical composition of the LDH has been characterised as {Zn_0.69Al_0.28(OH)_{2.07}Cl0.180.33H2O with a particle size in the range of 100-200 nm. The synthesised LDH has been found to be a good adsorbent of Cr(VI) (as Cr2O7²) in the chromium concentration range of 25-250 ppm with a maximum loading capacity of 48 x 10³ kg/kg at around 125 ppm. Adsorption of Cr(VI) on the Zn Al-Cl surface follows a first order kinetics. Cr(VI) adsorption on the Zn-Al-Cl LDH surface increases with increasing pH 7. There is no leaching of Al from the LDH in the pH range of 4-10 Zn leaching is also low beyond pH 7. There is practically no Cr(VI) desorption from the LDH surface in the pH range of 7.9. Cr(VI) adsorption mechanism other than anion exchange.Presence of associated anions in the solution interferes Cr(VI) adsorption on the Zn-Al-Cl LDH.}

illus, tables, ref

004817   Tarafder S;Ranganath V R;Johri P (Fatigue & Fracture Group, National Metallurgical Laboratory, Jamshedpur 831 007) : Fracture resistance of PHT piping material to simulated seismic loading. Metals Mater Process 2004, 16(2-3), 295-306.

Fracture resistance characteristics of the constituent materials is an important input for leak-before-break (LBB) design of primary heat transport (PHT) piping of nuclear power plants. For LBB analysis of piping behaviour under seismic activity the appropriate fracture resistance data generated under seismic-type load excursions are required. Examines the fracture response of SA 333 Grade 6 steel used as PHT piping material in Indian pressurised heavy water reactors under simulated seismic loading. It was observed that fracture resistance of the PHT piping material may be substantially deteriorated under seismic conditions consisting of periodic load reversals superimposed on a monotonically increasing tearing loading. The degree of degradation of fracture resistance is dependent upon the extent of load reversal and the frequency at which such reversals take place. For load reversals that do not lead to compressive loading. Fracture resistance is not greatly affected. When periodic compressive excursions occur during seismic-type loading the fracture toughness of the PHT piping material can decrease to ~50% of the value shown under purely monotonic tearing.

8 illus, 1 table, 10 ref

004816   Suriyanarayanan S;Jayakumar D;Devi M P; Balasubramanian S (Bharathiar University, Department of Environmental Sciences, Coimbatore 641 046) : Monitoring of ground water in and around waste paper based paper mill in Kanchipuram. Indian J envir Prot 2003, 23(9), 1033-7.

Ground water quality is studied by systematic collection and analysis of samples, which enable us to properly manage the resources. A systematic study of the ground water for 11 selected parameters of 12 ground water samples around a waste paper based paper mill at Bukkathurai in Kanchipuram district has been investigated over a period of 3 month from November 2001 to January 2002. The pH of all water samples around 7.0 and occasional by alkaline. In about 12 well the recommended limits for water quality standard is exceeded in one or two parameters. In general the ground water of this area are suitable for irrigation.

2 illus, 3 tables, 7 ref

004815   Srivastava D;Banerjee S;Ranganathan S (Materials Science Division, Bhabha Atomic Research Center, Mumbai 400 085) : The crystallography of BCC to HCP martensitic transformation in dilute Zr-Nb alloys: Part II: application of phenomenological theory of martensitic transformation. Trans Indian Inst Metals 2004, 57(5), 427-49.

The crystallography of the bcc-hcp martensitic transformation in the Zr-2.5% Nb alloy has been analyzed on the basis of the invariant plane strain (IPS) criterion. The Wechsler, Lieberman and Read (W-L-R theory) matrix method of the phenomenological theory of martensitic transformations has been used for computing the crystallographic features such as: orientation relationships, transformation shape strains, the magnitudes and the directions of shape strain shears and the habit planes. The calculated thickness ratio of the two twin fraction of the internaly twined martensite in the Zr-2.5 Nb alloy has been found to be 4.12 and 7.83 for {1101}_H <60>4153<62>_H and {0112}_H <60>0111<62>_H twinning modes respectively. The habit plane for {1101}_H <60>2113<62>_H shear system and {1101}_H <60>4153<62>_H twinning mode has been computed to be {4.34, 3.16, 3}_C and {4.67, 4.87, 3} respectively. The crystallographic parameters have been computed for the internally slipped martensite for most extensively reported {1011}_H <60>2113<62> shear system as well as for two other frequently reported shear systems, {2112}_H <60>2113<62>_H and {1121}_H <60>2113<62>H. In the case of {1011}H <60>2113<62>_H shear system the computed magnitude of the inhomogenous shear and habit plane has been found to the 0.288 and {4,2,4,3} respectively. The crystallographic parameters computed for the martensite of the Zr-2.5% Nb alloy remain the same for other dilute zirconium base binary alloys, as the lattice parameters and the lattice correspondences do not vary substantially. The predicted crystallographic parameters in the study has been compared with the expermerimentally-determined values.

6 illus, 10 tables, 35 ref

004814   Sonawane V Y;Shrivastava V S (G T P College, Centre for P G Research in Chemistry, Nandurbar 425 412) : Status of hazardous metals in different water samples in an around Pen-Khopoli industrial estate. Indian J envir Prot 2003, 23(9), 986-9.

Six water samples were collected from different places in and around Pen-Phopoli (Maharashtra) industrial estate. In these samples, Zn, Cu, As, Cd, Pb, Fe and Ni were analysed by atomic adsorption spectrophotometer. This analysis was monitored for six months and results obtained were compained with standards of WHO and ICMR. Beside the metallic analysis same samples were analysed for COD and BOD. The analysis of results concluded that except sample no. S1 and S2 all the other water samples are suitable for drinking purposes.

004813   Singla A;Rachna;Sharma S K;John S (Punjab Engineering College, Environmental Engineering Laboratory, Department of Civil Engineering, Chandigarh 160 012) : Heavy metal sorption, mobility and distribution in soil metal. Indian J envir Prot 2003, 23(7), 800-4.

Heavy metal sorption and mobility in soil is of importance in land pollution studies. Laboratory column studies were conducted to investigate the sorption capacity and transport of Pb, Cr, and Cd through soil. The agricultural soil exhibited a higher metal sorption capacity in comparison to the river sand. The order of mobility was Cr<62>Cd<62>Pb. Top layers of the soil retained most of the metals.

5 illus, 1 table, 14 ref

004812   Singh R P;Ray S K (Central Mining Research Institute, , Barwa Road, Dhanbad 826 001) : Study on control of disastrous open fires in underground coalmines. J scient ind Res 2004, 63(12), 1010-8.

Outbreak of open fires in coalmines is one of the major causes of disaster. To understand the complex phenomenon of open fires and to work out suitable fire suppression techniques, a mine fire model gallery is designed and constructed at Central Mining Research Institute, Dhanbad. The gallery is equipped with state-of-the-art instrumentation system to monitor the important fire parameters. Three fire suppression techniques-liquid nitrogen, high-pressure high stability (HPHS) nitrogen foam,and water mist, were tried in three sets of experiments. It was observed that either HPHS nitrogen foam or water mist can be used to control the open fires. Despite control of open fires the water mist has other advantages, which can prevent the open fire to become disastrous.

7 illus, 3 tables, 8 ref

004811   Singh R;Bhattacharyya P;Bhattacharyya K K; Maulik S C (National Metallurgical Laboratory, , Jamshedpur 831 007) : Reduction of alumina in indian iron ores. Metals Mater Process 2004, 16(2-3), 157-70.

India has got the sixth largest reserves of iron ores which is the basic raw material for iron steel making. Inspite of being rich in iron, Indian iron ores contain high alumina as impurities. High alumina content of iron ore is not favourable for efficient operation of blast furnaces. Deals with the available resources and characteristics of Indian iron ores. The deleterious effects of high alumina, the present plant practices for lowering alumina and their limitations are analysed. The process options for lowering alumina are discussed and salient results on new processing techniques are presented, in the light of recent developments and the rich experiences of NML on benefication of iron ores. From the point of view of resource conservation and environment protection, complete beneficiation of iron ores covering lumps, fines and slimes and the utilisation of blue dust, beneficiated fines and slimes are emphasised.

9 illus, 9 tables, 26 ref

004810   Singh D D;Ghosh R;Singh R J (Applied Chemistry & Corrosion Divison, National Metallurgical Laboratory, Jamshedpur 831 007) : Corrosion performance of steel rebars embedded in chloride contaminated concrete mortars-role of surface pre-treatments. Metals Mater Process 2004, 16(2-3), 313-26.

Incorporates the studies related to the role of surface condition (surface having black oxide, brown rust and bright & polished) of thermo mechanically treated (TMT) low carbon mild steel rebars embedded in chloride contaminated concrete mortars on their corrosion resistance. It is established that the presence of brown rust or black oxide scale on rebars' surface has an accelerating effect on uniform and localised corrosion rates. The mortars embedded with rebars having mill scale cracked within 450 days of exposure in the test environment whereas the mortars with descaled rebars took 760 days of exposure for cracking. The presence of black and brown oxides on the rebars surface and embedded in concrete accelerated the corrosion which has been ascertained by weight loss, electrochemical direct current polarisation and alternating current impedance spectroscopy (EIS) studies. The tests of such specimens exposed directly to cement slurry also provide the same conclusion. Cyclic polarisation plots indicate that the steel rebars having oxide on their surface are prone to crevice corrosion, a widely reported localised type of corrosion attack in concrete structures. XRD (X-ray diffraction) studies of the rusts generated on rebars ssurface during their exposure show the formation of unstable alkaganite {β-FeO (OH)} and hematite (Fe₂O₃) phases. SEM (scanning electron, microscopy) studies show that nodular types of corrosion products are formed on the pre-scaled surface of embedded rebars. The corrosion rate of descaled surface exposed under identical test conditions exhibit comparatively lower rate of corrosion than the oxidecovered surfaces. This difference in corosion rate is attributed to the cathodic de-polarisation of corrosion reaction caused due to the presence of Fe³⁺ ions of oxides on the corroding surface. The pre-rusted surface (under controlled conditions) exhibits almost the same behaviour as the rebars with scale. The results have been discussed in light of kinetics of polarisation of reduction reaction and film formation at the steel surface.

10 illus, 24 ref

004809   Saxena M (Applied Sciences and Humanities Dep, Moradabad Institute of Technology, Moradabad-244 001) : Cyrstallization kinetics of amorphous Te_x(Bi₂Se₃)_1-x glasses. Bull Mater Sci 2004, 27(6), 543-6.

The activation energy plays a dominant role in deciding the utility of the material for the specific purpose-here storage. The dependence of the peak temperature of crystallization (T_p) on the composition and heating rate (β) has been studied here. From the heating rate dependence, T_p, the activation energy for crystallization (E_c) has been evaluated. The activation energy, E_c, calculated using three different approaches is found to decrease with the increase in Bi content. This analysis helps in finding the suitability of an alloy to be used in phase transition optical memories/switches. The results have been analysed using Kissinger's equation for non-isothermal crystallization of materials.

6 illus, 17 ref

004808   Ray A K;Mandal S;Ravi Kumar B;Das S;Rao V (National Metallurgical Laboratory(CSIR), , Jamshedpur 831 007) : Ceramic to ceramic brazing through active filler alloy. Metals Mater Process 2004, 16(2-3), 259-67.

Ti based active filler alloy has been used for joining sintered alumina. Silver and copper base alloys with varying compositions of Ag:Cu=72:28, 60:40,, 50:50 and 30:70 (by wt%) were prepared. 1-3 wt% of Ti was incorporated in the Ag-Cu base alloys as an active filler element. The filler alloys thus obtained were characterised by XRD. SEM and EDX. Thin foil (0.2-0.1mm thick) of the filelr alloy was obtained and placed in between the two ceramic (alumina) pieces. The ceramic-filler alloy-ceramic was held firm by placing a suitable weight and heated in a graphite resistance furnace under 30-50 millitorr pressure at temperatures such as 1073, 1173, 1273, 1373 and 1473 K. In all cases the soaking time was kept 15 min. The optimum temperature and time were determined after examining the brazed samples through electron probe micro analyser (EPMA), scanning electron microscopy-energy despersive X-ray analysis (SEM-EDX), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The study of the interface between the ceramics by EPMA, SEM-EDX, TEM and XRD has shown interesting results. The average thickness of the interface was 4-9m. Most of the Ti present in the filler alloy was found at the interface as TiO and Ti₃Cu₃O.

8 illus, 1 table, 31 ref

004807   Rasool S;Harakishore K;Satyakala M;Murty U S (Indian Institute of Chemical Technology, Biology Division, , Hyderabad 500 007) : Studies on the physico-chemical parameters of Rankala lake, Kolhapur. Indian J envir Prot 2003, 23(9), 961-3.

Physico-chemical parameters of Rankala Lake, Kolhapur, Maharashtra were studied for a period of one year. Parameters, like pH, total solids, chlorides, sulphates, phosphates, calcium, magnesium, alkalinity, hardness, BOD and COD were estimated and tabulated as seasonwise. The results revealed that the water contained high content of sulphates, phosphates and chlorides. Hence this lake water is not suitable for direct consumption, as it is not in the permissible limits of drinking water. The lake can be considered as moderately polluted which promotes the water weeds, like Eicchornia crassipes.

1 illus, 1 table, 5 ref

004806   Ramamurthy N;Raju S;Subashini J; Thillaivelavan K (Annamalai University, Department of Physics, Annamalai Nagar 608 002) : AAS-analysis of pollutants of Palar river in Tamilnadu. Indian J envir Prot 2003, 23(9), 999-1002.

Tannery is one of the major water consuming industry responsible for causing environmental pollution. The Vaniyambadi area, which has many tannery industries along the banks of Palar river, is a major source of environmental pollution. Concentration of various trace metals, like Cu, Zn, Cd, Pb, Ni, As and Cr present in Palar river, Vaniyambadi area are determined and the intensity of pollution is assessed.

1 illus, 1 table, 8 ref

004805   Rajurkar N S;Nongbri B;Patwardhan A M (University of Pune, Department of Chemistry, Pune 411 007) : Water quality status of river Umkhrah at Shillong. Indian J envir Prot 2003, 23(9), 990-8.

River Umkhrah is the major river in Shillong that passes through some areas across the city. Domestic waste, solid waste, agricultural runoff from surrounding areas is entering into the river bodies through different drains and channels. Water samples at various locations from this river were collected and analysed for different physico-chemical and biological parameters to assess the quality of the river system. The study revealed that the overall daily input of waste let into the river water has resulted in the deterioration of water quality.

17 illus, 1 table, 4 ref

004804   Raju G B;Prabhakar S;Subba Rao S (National Metallurgical Laboratory, Madras Centre CSIR Madras Complex, Taramani, Chennai-600 113) : Development of indigenous column flotation technology at nml for the beneficiation of low grade ores. Metals Mater Process 2004, 16(2-3), 143-56.

NML Madras Centre has designed and developed indigenous automated flotation columns as part of its long term R&D program on the utilization of low-grade ores of India. Both laboratory size and semi-commercial flotation columns were extensively field tested in different mineral processing plants owned by Hindustan Copper Limited, Hindustan Zinc Limited, Kudremukh Iron Ore Company Limited, Sociedade De Fomento Industrial Limited, Bharat Gold Mines Limited, Gujarat Mineral Development Corporation Limited and Indian Rare Earths Limited for the beneficiation of copper, lead and zinc, iron, gold, fluorspar and sillimanite. State-of-the-art equipment was incorporated in both laboratory and semi-commercial flotation columns. Advantages of column flotation technology over conventional flotation machines and salient features of the NML flotation column were discussed. Flotation test results obtained both by flotation column and conventional cells were compared. Also highlights the potential of column flotation technology in achieving better metallurgical results compared to conventional flotation cells.

7 illus, 9 tables, 21 ref

004803   Ozturk H;Saracoglu H;Caliskan N (Gazi University, Kirsehir Arts and Sciences Faculty, 40100, Kirsehir, Turkey) : Displacement and stress fields of hexagonal networks of intrinsic dislocations along a planar epilayer/substrate interface. Trans Indian Inst Metals 2004, 57(5), 461-6.

The displacement and stress fields were derived from Fourier analysis for hexagonal network of dislocation, which are periodic in two-dimensions. Analytical solutions were obtained within the framework of isotropic elasticity theory for a situation in which one of the media tends to infinity and the other is of thickness of h. By employing appropriate boundary conditions, the coefficients of displacement and stress fields have been found. These coefficients clearly show that the displacement and stress fields depend on h (thickness), μ (shear modulus), υ (Poisson's ratio), the geometry of the network of dislocations and Burgers vectors.

3 illus, 17 ref

004802   Ojha S N;Tewari S N (Department of Metallurgical Engineering, Banaras Hindu University, Varanasi 221 005) : Mushy zone characteristics and macrosegregation during directional solidification. Trans Indian Inst Metals 2004, 57(5), 475-83.

Directional solidification of an alloy containing Pb-5.8 wt% Sb has been carried out over growth rates varying from 1 to 10 μm s^-1 in a positive temperature gradient of 140 Kcm^-1. The microstructural examination indicated cellular to dendritic transition at a growth rate of 1.5 μm s^-1. An analysis of composition revealed a large macrosegregation of Sb along the longitudinal section of the directionally solidified alloys. The degree of macrosegregation was observed to increase with a decrease in the growth rate during solidification of the alloy. The microstructural analysis indicated a progressive increase in volume fraction of the soild phase, variation in shape factor of cells/dendtrites and decrease in the hydraulic radius as a function of distance from the solid-liquid interface in the mushy zone. These factors control the permeability of the mushy zone and resultant macrosegregation of the alloy. The macrosegregation behaviour of the alloy is discussed in light of thermosolutal convection in the mushy zone as well as in the melt ahead of the solid-liquid interface during directional solidification.

9 illus, 15 ref

004801   Neogy S;Srivastava D;Dey G K;Chakravartty J K;Banerjee S (Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085) : Annealing studies on Zr-1Nb and Zr-1Nb-1Sn-0.1Fe alloys. Trans Indian Inst Metals 2004, 57(5), 509-19.

This paper summarizes the experimental results of microstructure development and mechanical properties of two types of zirconium alloys, namely the quaternary Zr-1Nb-1Sn-0.1 Fe and the binary Zr-1Nb. Both these alloys and their derivatives are finding increasing applications as fuel tube materials and have the potential for meeting the requirement of high burn up fuel. This is reflected in the current international literature. It has been recognized that the level of tin required for imparting necessary corrosion resistance to zirconium based alloys can be brought down to about 1 % from the level of 1.5 % as in Zircaloy-2. The synergy of Sn and Nb additions is also known to be beneficial for both mechanical properties and aqueous corrosion behaviour of zirconium alloys. Microstructural studies on these alloys after different thermomechanical processing have revealed the shape, size distribution and the nature of precipitate phases, the extent of recrystallization of the matrix hcp α grains-the factors which are expected to have strong effects on both short term mechanical behavior and long term performance during service. The distribution of β_II particles in Zr-1Nb is of significance in the context of both mechanical and corrosion properties. The optimized fabrication condition has been found to generate the desired precipitate distribution in Zr-1Nb. Annealing studies on these alloys have been carried out. The annealed microstructure and morphology of constituent phase and precipitates have been studied in detail. Tensile properties of these alloys in different temperatures are also discussed. Microstructural features of hydrides formed in Zr-1Nb alloy are also reported.

6 illus, 2 tables, 13 ref

004800   Nayar S;Chakraborty J;Sinha A (National Metallurgical Laboratory, , Jamshedpur 831 007) : Biomimetic synthesis of superparamagnetic composites. Metals Mater Process 2004, 16(2-3), 241-5.

Design and construction of nanophase materials and their arrays offer a wealth of unique properties important for fundamental studies and technological applications. Studies on biomimetic synthesis, a derivative of biomineralization have established that anisotropy of reaction media and reactions in confined geometry can result in the shape anisotropy of synthesized nanoparticles. The effect of an external magnetic field on the morphology and arangement of biomimetically synthesized superparamagnetic iron oxide particles in pre-organized poly (vinylalcohol) and bovine serum albumin matrices have ben studied. It is interesting to note a high degree of morphological order, even in the presence of enhanced dipole-dipole interactions among the magnetic particles. No clustering or the particle growth occurred in presence of the magnetic field and particles retained their superparamagnetic nature.

4 illus, 18 ref

004799   Nayak J;Udupa K R;Hebbar K R;Nayak H V S (Metallurgical and Materials Engineering Dep, National Institute of Technology, Surathkal, PO Srinivasnagar-575 025) : Estimation of embrittlement during aging of AISI 316 stainless steel TIG welds. Bull Mater Sci 2004, 27(6), 511-5.

Weldments of AISI grade 316 stainless steel, having a ferrite content of 4-6% and a variety of nitrogen concentrations were prepared using a modified element implant technique. Charpy impact specimens prepared from these weldments were subjected to a variety of aging treatments. Impact toughness decreases with aging time at all aging temperatures. Nitrogen is found to be beneficial to toughness. An empirical relation connecting the aging temperature, aging time and nitrogen content with toughness has been developed which can be used to estimate te time for embrittlement.

7 illus, 2 tables, 13 ref

004798   Mitra A;Panda A K;Palit sagar S;Pal S K; Chattoraj I (National Metallurgical Laboratory, , Jamshedpur 831 007) : Development and characterisation of amorphous and nanocrystalline magnetic materials. Metals Mater Process 2004, 16(2-3), 269-77.

Over the last decade extensive research work was carried out at NML on the preparation, characterisation and development of amorphous and nanocrystalline materials for sensors. This included the development of amorphous materials indigenously in the form of amorphous ribbon as well as the characterisation of amorphous wires with square hysteresis loop suitable for switching devices. FeNbCuAlMnSib based amorophous materials developed at NML, exhibited excellent soft magnetic properties. Nanocrystalline μ-Fe (Si,Al) particle of about 5-6 nm dispersed in an amorphous matrix was the cause of such excellent soft magnetic properties. The switching behaviour of amorphous FeSiB alloy in the form of wire was investigated by incorporation of hydrogen into the system. It was found that hydrogen drastically changed the switching characteristics. It also altered the saturation magnetic moment of the materials. The switching behaviour was also altered by removing different surface layers of the wire by selective etching. The amorphous wire has unique domain structure generated during differential cooling process. This unique domain structure makes it suitable for Giant Magneto-Impedance (GMI) materials. A systematic study on GMI properties was conducted and it was found that the material having nearly zero magnetostriction constant exhibited excellent GMI property.

9 illus, 1 table, 16 ref

004797   Mishra S K;athak L C (National Metallurgical Laboratory, , Jamshedpur 831 007) : Self-propagating high-temperature synthesis (SHS) of advanced high temperature ceramic materials. Metals Mater Process 2004, 16(2-3), 247-57.

Researchers at the National Metallurgical Laboratory (NML), Jamshedpur, have developed several processes for the fabrication of various advanced high temperature monolithic and composite materials namely ZrB₂, TiC, ZrB₂-Al₂O₃, TiB₂, TiB₂TiC, ZrB₂ TiC etc. by self-propagating high-temperature synthesis (SHS) technique. At NML, the studies were focused on the SHS processing, mechanism of phase formation, microstructure evolution, sintering studies of SHS produced powders and in-situ formation of advanced materials and composites. The SHS powder showed better sinterabilities as compared to the conventionally prepared powder. SHS techniques were successfully used for the fabrication of in-situ composite powders and also attain high densification through SHS dynamic compaction. Several aspects of the SHS processing are emphasized.

14 illus, 2 tables, 28 ref

004796   Mehrotra S P;Shamsi M R R I (National Metallurgical Laboratory, , Jamshedpur 831 007) : Near-net-shape casting of flat products: present status and future trends. Metals Mater Process 2004, 16(2-3), 227-39.

Advantages of producing metal slabs/strips directly from molten metal are numerous. Hence, lots of efforts are going on in this direction. Attempts have been made to produce metal strips by different methods but because of secrecy of these projects. Little information is available. Information about continuous thin slab casters and various types of strip casters is compiled and presented. The strip casters discussed include, belt casters roll casters spray deposit caster theocaster and powder rolling caster.

14 illus, 2 tables, 35 ref