007227   Vyas A K;Vohra S;Gupta A B (NO, Malaviya Natn Inst of Technol, Jaipur-302 017) : Development of Cost functions for circular tanks for sewage treatment plants. Indian J envir Prot 2005, 25(1), 70-75.

Detailed cost estimated for circular tanks of 2 to 40 diameter were prepared. The designs were worked out using SEPL-Tank software following IS 3370 and IS 456. Detailed quantities of steel and concrete were compted and cost curves were derived. The equation of cost and capacity came out to be cost = 0.0034 volume. The cost per litre capacity varied between Rs. 2.15 to Rs. 0.34 and was observed to be constant for tanks of diameter greater than 35 m

3 illus, 4 tables, 5 ref

007226   Verma V K (Indian Rare Earths Ltd., , Mumbai) : Mineral sands and rare earths-marketing challenge. J Mines Metals Fuels 2005, 53(1-2), 36-7.

.

007225   Upadhyaya G S (Dep Mater Metall Engng, Indian Inst of Technol, Kanpur-208 016) : Powder metallurgical processing and metal purity: a case for capacitor grade sintered tantalum. Bull Mater Sci 2005, 28(4), 305-7.

The paper reviews the role of sintered tantalum as volumetric efficient electrical capacitor. Powder characteristics and sintering aspects are discussed. The role of impurities in influencing the electrical properties has been described. Today's driving force behind the Ta market is the use of surface mounted versions known as chip types, for applications requiring a wide range of operational temperature, such as automotive electronics.

2 illus, 1 table, 11 ref

007224   Tiwari N C;Keny A (Kirloskar Brothers Ltd., , Dewas, Madhya Pradesh) : Contribution to energy-saving by use of mechanical seal in agricultural pumps. Indian Pumps 2005, 37(2), 9-11.

2 illus

007223   Suresh Kumar S (Indian Rare Earths Ltd., , Mumbai) : Contribution of in-house research and development to growth and prosperity of IREL with chronology of achievements. J Mines Metals Fuels 2005, 53(1-2), 16-35.

3 illus

007222   Sreenivasan K P;Velayudhan T (Indian Earths Ltd., , Chatrapur, Ganjam, Orissa) : Beach sand industry of Manavalakurichi. J Mines Metals Fuels 2005, 53(1-2), 20-6.

2 illus, 2 ref

007221   Sivasubramanian S (Indian Rare Earths Ltd., , Mumbai) : Mineral sand industry- present scenario and future options. J Mines Metals Fuels 2005, 53(1-2), 8-15.

2 tables

007220   Sivanandam S N;Sumathi S;Deepa S N (Dep Electl Electron Engng, PSG Coll of Technol, Coimbatore-641004) : Design and implementation of PLC cum micro-controller based electrically synchronized lift. Indian J Engng Mater Sci 2005, 12(4), 269-77.

Automobile industry is developing most extravagantly. The maintenance of the automobiles plays an important role, which is achieved by latest service station equipments. Electro-mechanical two-post lift is used to lift the vehicle to top or bottom and performs the required service operations under chassis. As in the present design and fabrication of the two-post lift, sprockets and chain mechanism are present for the transmission of the drive, but this results in slight non-linearity in the arm arrangements. This non-linearity in worst case may result in destruction of the automobile placed on the lift. The aim of the paper is to avoid this non-linearity; hence, synchronization control of the arm movements is proposed for automating the lift, by removing the sprocket and chain mechanisms. The synchronization is implemented using two types of controllers, which includes micro-controller and the programmable logic controller. An inductive proximity sensor is selected to sense the rotation of the motors and produce pulses, which is used to control the movement of arm arrangements. The micro-controller programming is implemented using the software AVR Studio 3.5. The programmable logic controller programming is performed using the software STEP-7 Micro/Win 32.

11 illus, 4 tables, 17 ref

007219   Sinha O P;Chatterjee M;Sarma V V R S;Jha S N (Mishra Dhatu Nigam Limited, , P O Kanchanbagh, Hyderabad-500 058) : Effect of residual elements on high performance nickel base superalloys for gas turbines and strategies for manufacture. Bull Mater Sci 2005, 28(4), 379-82.

The need for better gas turbine operating efficiency and reliability has resulted in tightening of specification and acceptance standards. It has been realized that some elements even at trace level, can have disastrous effect on high temperature properties. The paper highlights the adverse effect of tramp elements and strategies that should be adopted to produce high purity superalloys.

8 illus, 8 ref

007218   Singhal S K;Singh B P (Div Engng Mater, Natn Phys Laboratory, Dr. K S Krishnan Marg, New Delhi-110 012, Email: sksinghal@mail.nplindia.ernet.in) : Sintering of cubic boron nitride under high pressures and temperatures in the presence of boron carbide as the binding material. Indian J Engng Mater Sci 2005, 12(4), 325-30.

Sintering of cubic boron nitride (cBN) was carried out by subjecting fine powders of cBN to high pressures and temperatures (P = 50-60 kb, T= 1200-1500°C)in the presence of boron carbide as the main binding material together with a small amount of aluminium nitride. The composites were characterized by X-ray diffraction, scanning electron microscopy, FTIR, Raman Spectroscopy and microhardness measurements. Best composites with a maximum microhardness of about 3700 kg/mm^{2 were obtained at around 50 kb, 1450°C using 75 wt% of cBN in the mixture. No peaks due to hexagonal boron nitride were observed in the XRD patterns.}

4 illus, 20 ref

007217   Singh S N;Gandotra R;Singh P K;Chakravarty B C (Div Electronic Mater, Natn Phys Laboratory, New Delhi-110 012, Email: snsingh@mail.nplindia.ernet.in) : Application of photoconductivity decay and photocurrent generation methods for determination of minority carrier lifetime in silicon. Bull Mater Sci 2005, 28(4), 317-23.

Minority carrier lifeline, τ, is one of the most important parameters which has a decisive effect on the performance of silicon devices based on excess carriers. The value of τ is greatly affected by the presence of impurities and defects in silicon and its value provides a fair indication of quality of the material. Photoconductivity decay (PCD) and photocurrent generation (PCG) methods are simple and low cost methods of measurement of minority carrier lifetime in silicon wafers. However, their application requires care. The PCD method can give quite misleading results in case of polycrystalline wafers if there exists potential barriers at the grain boundaries which may affect majority carrier mobility significantly. PCG needs creation of an induced p⁺-p-n⁺ structure of substantially good quality that should not degrade with time. For PCG method the τ measurement under vacuum conditions provides correct and consistent results.

11 illus, 2 tables, 7 ref

007216   Singh N B;Vellmer C;Middendorf B (Dep Chem, DDU Gorakhpur Univ, Gorakhpur-273 009, Email: midden@uni-kassel.de) : Effect of carboxylic acids on the morphology, physical characteristics and hydration of α-hemihydrate plaster. Indian J Engng Mater Sci 2005, 12(4), 37-44.

Hydration of α-hemihydrate in the presence of different concentrations of tartaric, succinic, malic and cirtic acids was studied. All the acids, except tartaric acid, retard the hydrations. pH measurements have shown that during hydration acids are adsorbed at solid surfaces, leading to the retardation of hydration. E-modulus of elasticity, tensile strengths, total porosity, compressive strength, morphological and temperature changes during hydration were studied. It is found that morphological changes the strength properties.

11 illus, 1 table, 5 ref

007215   Shehata O S (Phys Chem Dep, Natn Res Cent, Dokki, Cairo, Egypt) : Electrochemical impedance and surface analysis of rebars in cement pastes with chemical concrete admixtures. Bull Electrochem 2005, 21(4), 179-84.

The deterioration of concrete structures due to corrosion of steel reinforcements is often a major problem in civil engineering. Scanning electron microscopy and electrochemical impedance spectroscopy can be used to study passivity and corrosion mechanisms. Impedance behavior and the effect of some chemical concrete admixtures on corrosion behavior of reinforcing steel has been discussed.

3 illus, 6 tables, 14 ref

007214   Sharma Y;Sil A;Yadav K L (Dep Metall Mater Engng, Indian Insititute of Technol, Roorkee-247 667, Email: anj_sil@yahoo.co.uk) : Structural and dielectric properties of MgO doped 0.8PMN-0.2PT solid solution. Indian J Engng Mater Sci 2005, 12(4), 317-20.

Perovskite PMN and 0.8 PMN-0.2 PT solid solution were prepared by columbite processing technique. The effect of minor addition of excess (1 wt.%) MgO on the microstructure and dielectric constant of the samples in 0.8PMN-0.2PT sintered at 900°C and 1000°C for 4 h in PbO-rich atmosphere was investigated. The addition has resulted higher dielectric constant with an increase in transition temperature. Also, average grain size has increased.Due to the excess MgO addition, the nature of phase transition has also been changed from diffuse to near normal behaviour.

3 illus, 17 ref

007213   Shah N A;Malik M A (Postgrad Dep Electron Instrumentation Technol, Univ of Kashmir, Srinagar-190 006) : High input impedance voltage-mode lowpass, bandpass, highpass and notch filter using current feedback amplifiers. Indian J Engng Mater Sci 2005, 12(4), 278-80.

The paper presents a New voltage-mode (VM) high input impedance filter having a single input and four low impedance outputs. The proposed circuit employs four current feedback amplifiers (CFAs) and six passive elements, four of them are grounded and enjoys the following advantages: simultaneous realisation of lowpass (LP),bandpass (BP), highpass (HP) and notch filtering functions explicitly, cascadability, independent control of resonance frequency (ω₀) and bandwidth (ω₀/Q), orthogonal control of resonance frequency (ω₀) and quality factor (Q), no requirements for component matching conditions, use of two grounded capacitors which are ideal for IC implementation and low passive sensitivity figures. Experimental and PSPICE simulation results are given to verify the theoretical calculations.

3 illus, 13 ref

007212   Reddy G A;Ganesan V (Internal Combust Engine Lab Dep Mechanical Engng, Indian Inst of Technol Madras, Chennai-600 036) : A numerical study of pre-diffuser optimization of an aero gas turbine combustion chamber. Indian J Engng Mater Sci 2005, 12(4), 281-91.

Desscribes the attempts made in the optimization of pre-diffuser geometry of an aero gas turbine combustion chamber for obtaining minimum total pressure losses and for good static pressure recovery. Optimization of pre-diffuser has been attempted by changing the geometric parameters like length, divergence angle and wall contour. A 20° sector has been considered for the study because of the periodicity with respect to the air blast atomizer. The geometry is modeled using GAMBIT and CATIA software. Meshing is done by GAMBIT. The governing equations are solved using the SIMPLE algorithm with iterative multigrid acceleration. Turbulence effects are simulated using the (RNG) k-ε model. Flow field characteristics have been analyzed. Optimization is attempted from the point of view of achieving minimum pressure loss. From the study it is concluded that a 6° straight walled pre-diffuser with area ratio of 1.6594 and a dump gap ratio (D/H) of 1.08 is found to be most optimum, considering the flow development and minimum total pressure loss.

13 illus, 6 tables, 11 ref

007211   Rajendranathan Nair K (Indian Rare Earths Limited, , Kollam District, Kerala) : Historical evolution of minerals division, chavara-technology upgradation and achievements. J Mines Metals Fuels 2005, 53(1-2), 10-5.

6 illus

007210   Panigrahi K N (Indian Rare Earths Ltd., , Chatrapur, Ganjam, Orissa) : Challenges in Orissa sands complex (OSCOM) and turn around in last two decades. J Mines Metals Fuels 2005, 53(1-2), 32-7.

2 illus

007209   Naveen Kumar;Singh V K;Yadav R R (Dep Math Fac Sci, Banaras Hindu Univ, Varanasi-221 005) : Distribution of pulse type uniform input in aquifers in tropical regions. Indian J Engng Mater Sci 2005, 12(4), 356-62.

Mathmatical models for the distribution of solute concentration of uniform input of pulse type along sinusoidally varying unsteady longitudinal velocity through such inhomogeneous aquifers of finite as well as semi-infinite extents whose main source of replenishment is infiltration during rains. A new time variable is introduced by using an expression in old time variable. Numerical solutions of such models are obtained using finite difference approximations. At initial stage the dispersion problem is considered steady one in homogeneous aquifer. Its solution is considered as initial condition for the respective unsteady problems. To achieve minimum time period of computation, the parameters of the problem are non-dimensionalized in terms of the existing variables in cases of semi-infinite and finite aquifers separately. The effects of inhomogeneity in both cases are shown through illustrations.

2 illus

007208   Nagesh S K;Revannasiddiah D;Shastry S V K (Electl Integraion Div, ISRO Satellite Cent, Airport Road, Bangalore-560 017, Email: sknagesh@isac.ernet.in) : Investigation of multipactor breakdown in communication satellite microwave co-axial systems. Pramana J Phys 2005, 64(1), 95-110.

Multipactor breakdown or multipactor discharge is a form of high frequency discharge that may occur in microwave components operating at very low pressures. Some RF components of multi-channel communication satellites have co-axial geometry and handle high RF power under near-vacuum conditions. The breakdown occurs due to secondary electron resonance, wherein electrons move back and forth in synchronism with the RF voltage across the gap between the inner and outer conductors of the co-axial structure. If the yield of secondary electrons from the walls of the co-axial structure is greater than unity, then the electron density increases with time and eventually leads to the breakdown. In the paper, the current due to the oscillating electrons in the co-axial geometry has been treated as a radially oriented Hertzian dipole. The electric field, due to this dipole, at any point in the coaxial structure, may then be determined by employing the dyadic Green's function technique. This field has been compared with the field that would exist in the absence of multipactor.

4 illus, 4 tables, 11 ref

007207   Munirathnam N R;Prasad D S;Rao J V;Prakash T L (Cent Mater Electron Technol, (C-MET) IDA Phase II Cherlapally, HCL Post, Hyderabad-500 051) : High purity tellurium production using dry refining processes. Bull Mater Sci 2005, 28(4), 309-11.

Tellurium (99-95 at.% purity) is purified using dry processes such as selective vapourization and zone melting in a thoroughly etched and cleaned quartz boat, under continuous flow of hydrogen (H₂) gas. The tellurium ingot was quadruple zone refined (QZR) under continuous flow of H₂ gas. Thus, the purified tellurium of ultra high purity (UHP) grade is analysed for 60 impurity elements in the periodic table using glow discharge mass spectrometer (GDMS). The sum of all elemental impurities indicate that the purity of tellurium as 7N (99.99999 at.%). The total content of gas and gas forming impurities like O, N and C are found to be within acceptable limits for opto-electronic applications.

1 table, 6 ref

007206   Mukherjee T K (Indian Rare Earths Limited, , Mumbai) : Indian Rare Earths Limited- a journey to prosperity. J Mines Metals Fuels 2005, 53(1-2), 3-7.

6 illus, 2 tables

007205   Misra A;Pankaj Kumar;Lokendra Kumar;Ganesh N; Gupta M;Dhawan S K;Kamalasanan M N;Subhas Chandra (OLED Lab Polymeric Soft Mater Sect, NPL, Dr. K S Krishnan Road, New Delhi-110 012, Email: mnkamal@mail.nplindia.ernet.in) : Blue-green emission from organic light emitting diodes based on aluminum complex. Indian J Engng Mater Sci 2005, 12(4), 321-4.

Bluish-green emission from double layer organic light emitting diode (OLED), based on an aluminium complex, bis-(2-methyl 8-hydroxyquinoline) aluminium hydroxide (Almq₂OH), as an emissive material and N, N-bis(3-methylphenyl)-N, N -bis(phenyl)benzidine (TPD), as hole transport material with an electro-luminescence maximum at 506 nm, has been reported. The good thermal stability, good performance for the OLED applications, and a noticeable blue shift in the electroluminescence, in comparison to Alq₃, make this Al complex a good contender for OLED applications for light emission in the blue-green region. It was also found that the devices based on this material have a slightly higher turn-on voltage than similar Alq₃ devices. This can be attributed to the higher energy-gap of the material. The photoluminescence and electroluminescence spectra are reported and a shift of 9 nm in peaks is observed. The current-voltage characteristics of the device have also been studied.

8 illus 14 ref

007204   Maharana L N;Nair V R (Indian Rare Earths Ltd., , Udyogamandal, Kerala) : Chronological evolution of rare earths division and diversification of its products for industrial/DAE use. J Mines Metals Fuels 2005, 53(1-2), 33-5.

2 illus

007203   Kulkarni B S (CWPRS, , Pune) : Checklist for selection of type of pump and important units/components in layout of huge pumping stations. Indian Pumps 2005, 37(2), 41-51.

3 illus

007202   Kulkarni B S (CWPRS, , Pune) : Different types of flow meters and applications. Indian Pumps 2005, 37(2), 32-40.

10 illus, 2 tables

007201   Kamat S M;Badari Narayana K;Kanade V S (Structs Grp, ISRO Satellite Cent, Bangalore-560 017) : Simulation of piezoelectric effect in nastran: experimental and analytical estimation of dynamic response of a circular plate. J Spacecraft Technol 2005, 15(2), 31-9.

Smart materials and structures are extensively used in various engineering fields including aerospace, heavy engineering, civil engineering and domestic appliances. Of the various smart materials piezo electrics are widely used for both sensing and actuation applications. Currently, only a few general-purpose softwares are available with built-in smart element (piezo) capability. It is possible to use other software as well, by using initial strain concepts. The paper brings out the simulation of the piezoelectric effect in 1D and 2D NASTRAN elements. The concept of thermal strain (or equivalent force) is used to simulate the strain generated by the piezo element in NASTRAN elements. Using this principle, the dynamic response of a circular plate excited by a piezo crystal is obtained and the present solutions are compared with the experimental results.

14 illus, 2 tables, 6 ref

007200   Kamal Singh;Quazi T;Upadhyay S;Sakharkar P (Dep Phys, Nagpur Univ, Nagpur-440 033) : Development of low permittivity material using fly ash. Indian J Engng Mater Sci 2005, 12(4), 345-50.

Dielectric behaviour of fly ash, barium titanate and three composites of fly ash and barium titanate have been measured in the temperature range 30-200°C and frequency range 100 Hz -1 MHz. It is observed that dielectric constant of fly ash and composite is low as compared to barium titanate. Moreover, the dielectric constant of fly ash and composites is independent of temperature in the entire range of temperature measurement. It is found that the experimental values of dielectric constant of the composites are in agreement with theoretical value calculated using logarithmic mixing rule given by Linchtenecker for determination of effective dielectric constant of the composite.

7 illus, 2 tables, 17 ref

007199   Kacher J;Ouvreloeil T (HSB Reliability Technologies Inc, , ) : How good is your preventive maintenance (PM) programme?. Indian Pumps 2005, 37(2), 12-4.

007198   Gnanabharanidharan N;Joshi P P (Mission Dev Grp, ISRO Satellite Cent, Bangalore-560 017) : Spacecraft in-orbit operations through multi-mission ground software. J Spacecraft Technol 2005, 15(2), 24-30.

Spacecraft operations require continuous monitoring of the health of the spacecraft and its commanding for the intended operations. These operations are carried out on the ground using sophisticated mission-oriented software tools. SCHEMACS is one such software which is being used for ISRO-built satellites. Design, development and maintenance of SCHEMACS is part of any satellite mission and a considerable amount of commonalities are found while developing SCHEMACS for various missions. By taking these factors into consideration and also the logical nature of software in general, a common unified version of SCHEMACS called multi-mission SCHEMACS has been developed and operationalized. At present, there exists a multi-mission software version suitable for LEO missions and another version suitable for supporting GEO missions. This multi-mission software version has been found useful in maintaining the software and in carrying out routine as well contingency satellite operations and health analyses with maximum ease and least effort. A single common LEO-SCHEMACS current version supports IRS-P4, TES and RESOURCESAT-1, while GEO-SCHEMACS supports INSAT-2E, INSAT-3A, 3B, 3C, 3E, KALPANA-1, GSAT-2&3. In this paper, various ways and approaches to achieve this kind of a software system have been explored and presented.

3 illus, 2 tables, 3 ref

007197   Ganeshan A S;Rathnakara S C;Gupta R;Jain A K (Mission Dev Grp, ISRO Satellite Cent, Bangalore-560 017) : Indian regional navigation satellite system (IRNSS) concept. J Spacecraft Technol 2005, 15(2), 19-23.

Paper presents a new concept of regional navigation satellite constellation, as an alternate to GPS constellation, for providing space based navigation support to various land, sea and air navigation users over the Indian region. The continuous visibility of GEO and GSO satellites for near-equator regions provides a promising alternative for regional navigation. The paper discusses the design considerations and parameters required for evolving such a regional system. The orbital characteristics, the criteria for choosing the constellation and the methodology have been highlighted. The error sources and the achievable accuracy for the user in the service area are brought out. Based on the studies, the proposed IRNSS consists of 7 satellites (3 in GEO and 4 in inclined GSO with 29 deg inclination.

4 illus, 2 tables, 2 ref

007196   Farrahi G H;Majzoobi G H;Chinekesh H (Sch Mechanical Engng, Sharif Univ of Technol, Tehran, Iran) : Effect of contact geometry on fretting fatigue life of aluminium alloy 2024-T3. Indian J Engng Mater Sci 2005, 12(4), 331-6.

The effect of contact geometry on fretting fatigue life was investigated by experiments and numerical simulation. The experiments were conducted for flat and cylindrical pads under the same contact normal force. The post-test examinations including crack growth measurements and fractography were carried out using optical and scanning electron microscopy (SEM). Numerical simulations of pad-specimen assembly with and without crack were performed using a finite element (FE) analysis. The experimental study revealed that the rate of crack growth was higher at the early stages of fretting fatigue for cylindrical pads. This stage corresponds to a higher K_II for cylindrical contact model. After this stage, the effects of fric tion force and K_II decrease and the effects of tensile stress and K_I become more significant. The experimental results also showed that fatigue life of AA2024 reduced by nearly 75% under fretting fatigue condition. However, the reduction for cy-lindrical contact geometry was more than that measured for flat contact model. The numerical results indicated that the maximum shear, tensile, and Von-Mises stresses which are thought to be the origin for initiation and growth of crack, occur at the trailing edge of the contact surface for flat and cylindrical pads. SEM examination confirmed that the crack initiated from the points of stress maxima.

7 illus, 12 ref

007195   Das A K (Indian Rare Earths Ltd., , Mumbai) : Growth of safety, health and environmental consciousness amongst IREL units for all round development. J Mines Metals Fuels 2005, 53(1-2), 38-42.

007194   Bidkar S H;Patil A G;Kapadi U R;Hundiwale D G (Dep Polym Chem, Sch of Chem Sci North Maharashtra Univ, P.O. Box 80, Jalgaon-425 001, Email: abhijitgpatil@indiatimes.com) : Evaluation of fly ash filled chloroprene elastomer composites. Indian J Engng Mater Sci 2005, 12(4), 351-5.

Filled elastomer composites are the popular for many engineering applications. Most commonly used fillers for non-black applications are china clay, talc and calcium carbonate. Fly ash, a waste mineral product of thermal power stations, was studied for the effect on physico-mechanical properties of polychloroprene composites. These composites filled with calcium carbonate, talc, china clay and fly ash were evaluated and technical properties were correlated with the help of chemical crosslinking and morphological study. The results proved that the properties were mainly associated with the high crystalline nature of the elastomer and also it could be concluded that fly ash could be utilized for curbing the environmental pollution with economic advantage.

7 illus, 3 tables, 17 ref

007193   Bhambure S R (Cent Wat Power Res Stn, , Pune) : Selection of pumps for special applications. Indian Pumps 2005, 37(2), 24-31.

1 illus, 4 tables

007192   Bhambure S R (Cent Wat Power Res Stn, , Pune-411 024) : Pumping system optimisation. Indian Pumps 2005, 37(2), 15-23.

10 illus, 1 table

007191   Badari Narayana K;Subba Rao P;Basha S K J; Muralidhar K V;Joseph T K;Kamat S M;Navalgund K H;Varghese C S (Structs Grp, ISRO-Satellite Cent, Bangalore-560 017) : Development of light weight structure for technology experiment satellite (TES). J Spacecraft Technol 2005, 15(2), 10-18.

Current trend in aerospace applications is to use high stiffness and strength composite materials in place of aluminum alloys, and growth is more focused on the use of sandwich constructions in aerospace applications. These constructions help to provide higher strength-to-weight and high stiffness-to-weight and greater stability to structures. A step in this direction is the development of all Al-sandwich construction bus for the Technology Experiment Satellite (TES). The article gives a brief summary of the basic design/analysis, fabrication process and tests carried out on the structure/flight models of TES. The results of analysis/tests carried out at various stages of development and the flight structural models are discussed. This design and development of Al-sandwich structures paved the way for the development of the more efficient sandwich structures made of CFRP, used in GSAT-II [1], GSAT-III and IRS-P5 subsequently.

11 illus, 3 tables, 5 ref

007190   Anna Rao A;Senthil Kumar S D R;Nagabushanam S (Control Systems Grp, ISRO Satellite Cent, Bangalore-560 017) : Lifetime enhancement of sputtered MoS₂ film lubricated ball bearings. J Spacecraft Technol 2005, 15(2), 1-9.

Sputtered MoS₂ lubrication and well-proven ion plated lead lubrication are the basic techniques for applying dry lubrication. Each process is selected based on the specific application, like definite lifetime, low torque noise and speed. Before selecting the lubricant and its process, it is mandatory to look into the lifetime endurance history of the lubricant. Based on individual experience, one can draw analogies for further decisions on the life assessment. Author has presented literature review trends in of dry lubricants and their attainable endurance life and hypothetical estimates of sputtered MoS₂ film lubrication selected with other combinations for long life requirements of ball bearings for spacecraft scanner applications. Author has also described the lifetime achieved with the combination of dry lubricants adapted at STL-ISA C which is 9x10⁸ cycles or greater.

6 illus, 1 table, 13 ref

007189   Altun F;Besdok E;Haktanir T;Palancioglu H M (Dep Civ Engng Fac Engng, The Erciyes Univ, Kayseri, Turkey, Email: faltun@erciyes.edu.tr) : Flexural response of reinforced-concrete beams based on multidimensional data analysis. Indian J Engng Mater Sci 2005, 12(4), 292-8.

Experimental investigation of behaviour and ultimate failure mechanisms of reinforced concrete (RC) beams help to better understand their in-situ reactions in RC structures and enable more realistic designs to be made. In the study, a total of nine RC beams with varying dimensions have been produced and subjected to flexural loading. The mid-section displacements and the loads have been measured. In order to investigate and model the load-displacement behaviour of RC beams of different configurations in detail, a multidimensional data analysis technique has been used. The triangular-base multidimensional data analysis (TBI) procedure applied herein is generally used for digital terrain modelling especially in geodesy and photogrammetric engineering and computer-aided modelling applications. Comparison of the experimentally determined relationships with those given by the developed TBI model has revealed close agreements. With the help of this TBI model, the approximate behaviour of an RC beam of certain dimensions for which the strength of concrete and the amount of reinforcement are given can be determined very closely. The classical finite element method has been used in the prediction of behaviours of RC beams in conjunction with the developed TBI model.

4 illus, 2 tables, 16 ref

007188   Ahmad S (MEMS Microsensors Lab, Cent Electron Engng Res Inst, Pilani-333 031) : Materials by design-prospects and challenges. Indian J Engng Mater Sci 2005, 12(4), 299-316.

104 ref

007187   Abhyankar S L (Indian Pump Manufacturers Ass, , ) : Domestic pumping and plumbing (Vast scope for conserving both water and energy). Indian Pumps 2005, 37(2), 5-8.

006164   Yang P;Li Y (Sch of Telecommunications Engng, Xidian Univ, Box 106, Xi'an, 710071, China, Email: ypbest@yahoo.com.cn ) : Investigation of scattering characteristics of for a conducting sphere moving at high velocity. Indian J Radio Space Phys 2005, 34(4), 243-7.

The scattered field of a conducting sphere moving at high velocity is investigated, when the incident wave is of arbitrary frequency. First the transformation of coordinates, transformation of vectors and the electromagnetic transformation are derived in detail, when one system of coordinates moves to another one along their Z-axis. The transformation of trigonometric function and that of the components of vector in spherical coordinates are presented for the first time. These transformations establish a theoretic basis for studying the scattered field by a target moving in high velocity. Utilizing the reference, the scattering characteristics of a conducting sphere moving in high velocity are investigated in detail. The expression of scattering section is obtained and simulations of that are presented. Results show that the forward scattered field is larger than that of the backward, as the sphere moves at a high velocity. The forward and backward scattered fields are not much influenced by the operating frequency and the Doppler effect plays the main role. The second radiation on the surface of the target is mainly electric dipole radiation.

5 illus, 6 ref

006163   White R (NO, , ) : Sustainable construction. Miner Metals Rev 2005, 31(6), 63-6, 69.

Reports about the indispensability of zinc in steel reinforcements, in the ABC sector.

1 illus, 1 table

006162   Vishwakarma R K;Vishvakarma B R (Dep of Electron Engng, Inst of Technol Banaras Hindu Univ, Varanasi-221 005) : Shorting pin loaded microstrip antenna for dual-band operation. Indian J Radio Space Phys 2005, 34(4), 281-4.

The series and shunt inductivity introduced by the probe and shorting pin respectively, in a single-feed shorted rectangular microstrip antenna has been evaluated theoretically using transmission line method. The proposed structure provides compact dual band operation using single feed mechanism. The input impedance, VSWR, is calculated theoretically. It is found that the ratio of the resonant frequencies highly depends on the position of shorting pin.

7 illus, 6 ref

006161   Vishnuvardhan S;Kandasamy S;Samuel Knight G M (Civil Engng, Anna Univ, Chennai-600 025, Email: gmsk@annauniv.edu) : Fatigue behaviour of cold-formed steel lipped angles. Trans Indian Inst Metals 2005, 58(2-3), 445-51.

Cold-formed steel sections are increasingly used nowadays in structural applications, due to their inherent properties like lightweight and high strength to weight ratio. Angles and channels, both with or without lips are the most common shapes used in practice. Cold-formed steel sections are thin and hence their behaviour is governed by local buckling. Even though static behaviour of cold-formed elements is well established, their fatigue behaviour under fluctuating loads needs to be investigated. The investigation examines the performance of cold-formed lipped single angle members subjected to fatigue loading. Fatigue tests were conducted on seventy six specimens under constant amplitude sinusoidal and stepped tensile loading conditions by varying the load ratio and the load level ratio for both low yield and high yield strength steel members under 5 Hz and 2 Hz respectively. The influence of fatigue parameters like maximum stress, stress range and type of loading on fatigue life is studied. An empirical relation is arrived at and the number of cycles to failure is proposed. Fatigue failure surface is also evolved for the two different grades of steel.

7 illus, 4 tables, 8 ref

006160   Verma G R;Pradhan M;Mohgaonkar A S (Min Engg Deptt, Engg Coll, Raipur-492 010) : Flyrock accidents. Indian Min Engng J 2005, 44(7-8), 21.

Today blasting has become an acceptable technique for rock breakage worldwide. Easting towards large opencast mines from traditional underground methods to cope with high production target demands for planning and executing blasts with large diameter holes and high explosive charges. Such a large size blast, if not properly designed and attended, may result in ground vibration, fly rock, air overpressure etc. endangering the safety of personnel and property and cause nuisance to the habitats. Blast area security and fly rock from surface blasting operations is one of the potential threat to the safety, witnessing for over 60% of all blasting-related injuries in surface coal, metal, and non-metal mines, therefore responsible blasting requires that rock throw be controlled to ensure that no danger will result to people and property. The paper presents a brief account of injuries due to fly rock and lack of blast area security in surface mines, an overview of fly rock problem and elucidates mitigation techniques.

2 tables, 16 ref, 6 place

006159   Valsan M;Nagesha A;Bhanu Sankara Rao K; Sandhya R;Mannan S L;Baldev Raj (Mater Dev Grp, Indira Gandhi Cent for Atom Res, Kalpakkam-603 102, Email: valsa@igcar.ernet.in) : Comparative evaluation of low cycle fatigue and creep-fatigue interaction behaviour of 316 and 316(N) weld metals and weld joints. Trans Indian Inst Metals 2005, 58(2-3), 323-9.

Comparative study of the low cycle fatigue (LCF) and creep-fatigue interaction behaviour of 316L(N) base metal, 316, 316(N) weld metals and weld joints is presented. Cyclic stress response of the weld metal and weld joints exhibited a softening regime. In general, the LCF and creep-fatigue lives exhibited by the base metal were higher than that of the weld metal. Weld joints exhibited the lowest life. It was observed that fatigue endurance of 316(N) weld metal-grade 2 was higher than that of the 316(N) weld metal grade 1. Further, 316 SS weld metal and weld joints showed superior fatigue lives compared to 316(N) weld metals and joints. The differences in fatigue and creep-fatigue lives of the weld metals and base metal under various testing conditions have been found to be associated with the basic differences in chemical composition and differences in the fatigue cracking mode. The LCF and creep-fatigue data compared well with that available from the literature and RCC-MR best fit curves.

6 illus, 2 tables, 13 ref

006158   Suryanarayana M V S;Boopati M;Sekhar K (Defence R & D Establishment, , Jhansi Road, Gwalior-474 002) : An improvised toxic gas calibrant mixtures generation assembly. J Instrum Soc India 2005, 35(3), 314-19.

Creation of a calibrant gas mixture generation facility is a prerequisite for any quality control facility for the calibration and evaluation of various detection and protection equipment. As standard gas mixtures of toxic chemicals like chemical warfare agents (CWAs) are not commercially available, it is imperative to create a custom made facility to create such standard toxic gas atmospheres. Here author has reported the design and development of such assembly, which is having provision for the generation of calibrant gas mixtures of toxic chemicals from low (0.01 mg/cu. M) concentrations. Diffusion, purging and permeation vessels can be used in this dynamic assembly depending upon the requirement. Provision for variation of other parameters like flow rates, temperatures, humidity etc. are incorporated in this assembly to attain requisite concentrations. This facility is being used in establishment time and again for the stage-wise evaluation of various indigenous detection gadgets and for the calibration of imported detection equipment.

2 illus, 3 ref

006157   Sundaresan S;Albert S K;Sireesha M; Swaminathan J;Kamaraj M (Dep of Metall and Mater Engng, Indian Inst of Technol, Madras, Email: ssundar@iitm.ac.in) : Stress rutpure behavior of transition joints between modified 9Cr-1Mo steel and 316 L(N) SS. Trans Indian Inst Metals 2005, 58(2-3), 493-9.

Stress rupture tests were performed on welded joints between modified 9Cr-lMo steel and Alloy 800 as part of a trimetallic (Grade 91 - Alloy 800 - 316 L(N) SS transition joint. For comparison, tests were also conducted on direct bimetallic (Grade 91 - 316LN) joints. The results show that the performance of the Grade 91 - Alloy 800 weldments is only a marginal improvement over the Grade 91 - 316LN joints. However, both these are considerably superior to joints involving the conventional 2.25Cr-lMo steel as the ferritic component. Most failures occurred in the Grade 91 HAZ 1-2 mm from the weld interface. Metallographic characterization revealed features that correlated well with the softening that occurred in this region during creep testing.

6 illus, 1 table, 16 ref

006156   Srinivasan V S;Nagesha A;Valsan M;Bhanu Sankara Rao K;Mannan S L;Baldev Raj (Mater Dev Grp, Indira Gandhi Cent for Atom Res (IGCAR), Kalpakkam-603 102, Email: vssrini@igcar.ernet.in) : Artificial neural network approach to low cycle fatigue and creep-fatigue interaction life prediction of modified 9Cr-1Mo ferritic steel. Trans Indian Inst Metals 2005, 58(2-3), 261-7.

Low cycle fatigue (LCF) behaviour of normalized and tempered modified 9Cr-lMo steel has been studied at various temperatures, strain amplitudes, strain rates and hold-times. The alloy in general showed a reduction in fatigue life with increase in temperature, increase in strain amplitude, decrease in strain rate and with an increase in the duration of hold time in tension. The capability of artificial neural network (ANN) approach to life prediction under LCF and creep-fatigue interaction conditions has been assessed by using the data from National Institute for Materials Science, Japan and that generated in laboratory. It is demonstrated that the predictions are well within a factor of two.

6 illus, 4 tables, 11 ref