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List of Publications for the Year-> 1999 Number of Records 328

Pancras, JP; Puri, BK, Simultaneous determination of rhodium and iridium using derivative spectrophotometry after preconcentration of their 2-(5-bromo-2-pyridylazo)-5-diethylaminophenal chelates onto microcrystalline naphthalene Source: ANALYTICAL SCIENCES, JAPAN SOC ANALYTICAL CHEM, Vol.15.00 Issue. 6 pp.575-580 1999.

Abstract: Rhodium and iridium were preconcentrated from a fairly large volume of their aqueous solutions using 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) and tetraphenylborate onto microcrystalline naphthalene in the pH ranges 5.0 - 6.5 and 3.5 - 5.5, respectively. The solid mass obtained after filtration was dissolved in 5 ml of dimethyl formamide (DMF). A derivative spectrophotometric method using a zero-crossing technique measurement is described for their simultaneous determination in mixtures. The determination of rhodium and iridium in the concentration ranges 0.15 - 12.5 and 0.25 - 10.0 mu g in 5 ml of the final DMF solutions, respectively, shows good linearity in the calibration plots. The detection limits are 72 ng and 133 ng for rhodium and iridium, respectively. Favorable selectivity in the presence of common ions was achieved by adding EDTA after complex formation. Various parameters were studied in order to optimize the conditions for the simultaneous determination of rhodium and iridium in various synthetic samples corresponding to their standard alloys.

Pancras, JP; Puri, BK, Ammonium tetraphenylborate-naphthalene adsorbent for the preconcentration and trace determination of uranium in standard alloys and synthetic samples using 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol by fourth-derivative spectrophotometry Source: MIKROCHIMICA ACTA, SPRINGER-VERLAG WIEN, Vol.130.00 Issue. 3 pp.203-208 1999.

Abstract: A solid ion-pair material produced from ammonium tetraphenylborate (ATPB) and naphthalene has been used for the preconcentration of uranium from the large volume of its aqueous complex samples. Uranium reacts with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) to form a water insoluble, coloured complex. This complex is quantitatively retained on the ATPB-naphthalene adsorbent filled in a column in the pH range 7.0-9.5 and at a flow rate of 2 ml/min. The solid mass from the column is dissolved with 5 ml of dimethylformamide (DMF) and uranium is determined by fourth-derivative spectrophotometry. The calibration curve is linear over the concentration range of 0.13-15.0 mu g of uranium in 5 mi of the final DMF solution. Seven replicate determinations of 6 mu g of uranium gave a mean peak height (peak-to-peak signal between 592 nm and 582 nm) of 1.02 with a relative standard deviation of 0.95%. The sensitivity is 0.8419 (d(4)A/d lambda(4))/(mu g ml(-1)) found from the slope of the calibration curve. The interference of a large number of anions and cations on the estimation of uranium has been studied and the method applied for the determination of uranium in coal fly ash, Zr-base alloy and some synthetic samples corresponding to standard alloys.

Pandey, DS; Sahay, AN; Sisodia, OS; Jha, NK; Sharma, P; Klaus, HE; Cabrera, A, Synthesis, characterization and crystal structure of [(eta(6)-C6Me6)Ru(mu-Cl)(3)Ru(eta(6)-C6Me6)]PF6 Source: JOURNAL OF ORGANOMETALLIC CHEMISTRY, ELSEVIER SCIENCE SA, Vol.592.00 Issue. 2 pp.278-282 1999.

Abstract: Reaction of [{Ru(eta(6)-C6Me6)Cl-2}(2)] with silver trifluoroacetate in presence of ammonium hexafluorophosphate and organonitriles viz. 4-cyanopyridine, 1,4-piperazine dicarbonitrile or 1,4-dicyanobenzene in methanol gives trichloro bridged complex [(eta(6)-C6Me6) Ru(mu-Cl)(3)Ru(eta(6)-C6Me6)]PF6. The complex has been characterized by various physico-chemical techniques (Elemental analyses, IR,UV-vis, H-1-, C-13-, P-31-NMR and FAB mass spectroscopy) and single crystal X-ray diffraction studies. [Crystal data: monoclinic, space group P2(1)c, a = 10.7604(9), b = 24.897(2), c = 10.8833(11) Angstrom, beta = 100.990(7)degrees. (C) 1999 Elsevier Science S.A. All rights reserved.

Parida, BP, Modelling of Indian summer monsoon rainfall using a four-parameter Kappa distribution Source: INTERNATIONAL JOURNAL OF CLIMATOLOGY, JOHN WILEY & SONS LTD, Vol.19.00 Issue. 12 pp.1389-1398 1999.

Abstract: In attempting to model the random behaviour of the Indian summer monsoon, the possibility of using a generalized four-parameter Kappa distribution representing a family of distributions has been explored. An L-Moment procedure developed by Hosking (1994) IBM J. Res. Dev., 38(3), 251-258, has been used for estimation of reliable rainfall quantiles. Using these estimates, isopluvial maps have been developed for some commonly used recurrence intervals (viz. 20, 50, 100, 200, 500 and 1000 years) which can be used by operational hydro-meteorologists. Copyright (C) 1999 Royal Meteorological Society.

Parthasarathy, KR, Extremal decision rules in quantum hypothesis testing Source: INFINITE DIMENSIONAL ANALYSIS QUANTUM PROBABILITY AND RELATED TOPICS, WORLD SCIENTIFIC PUBL CO PTE LTD, Vol.2.00 Issue. 4 pp.557-568 1999.

Abstract: We present a complete description of the extreme points of the convex set of all decision rules in testing multiple hypotheses concerning a quantum system whose states are described by density matrices in a finite-dimensional Hilbert space. Holevo's equations for an optimal decision are derived by methods of elementary calculus and a simple example is given in order to illustrate the nonuniqueness of optimal decision rules.

Pathak, LC; Mishra, SK; Bhattacharya, D; Chopra, KL, Sintering characteristics of Y-Ba-Cu-oxide-Ag-x superconductors Source: JOURNAL OF MATERIALS RESEARCH, MATERIALS RESEARCH SOCIETY, Vol.14.00 Issue. 11 pp.4148-4156 1999.

Abstract: The sintering characteristics of Y-Ba-Cu-oxide (YBCO)-Ag-x (x = 0 to 1.2) using thermomechanical analyzer were systematically investigated to understand the sintering mechanism of the metal superconductor composites. The addition of ag was observed to lower the sintering temperatures, and the apparent densities of the sintered compacts increased with x from 0 to 0.6. A further increase of x above 0.6 decreased the apparent densities of the sintered compacts. The presence of Ag globules in the YBCO-Ag compacts was observed by scanning electron microscopy and energy dispersive x-ray spectroscopy. The apparent activation energies for sintering of the powder compacts were estimated and observed to vary between 900 to 2000 kJ/mol. The formation of AgOx by absorbing oxygen from YBCO and sintering atmosphere possibly controls the sintering and superconducting behavior, incorporation of Ag into the matrix modifies the weak-link characteristics from superconductor-insulator-normal- superconductor (S-I-N-S) to superconductor-normal-superconductor (S-NS) type.

Pathak, LC; Mishra, SK; Bhattacharya, D; Chopra, KL, Degradation of BPSCCO superconductors during processing Source: JOURNAL OF MATERIALS SCIENCE, KLUWER ACADEMIC PUBL, Vol.34.00 Issue. 7 pp.1619-1624 1999.

Abstract: Evaporation losses of Bi, Sr, Cu and Pb during processing of Bi-Pb-Sr-Ca-Cu-oxide (BPSCCO) superconductors were observed, which affected the superconducting properties. Incongruent loss of Bi, Sr, Cu and Pb was reduced by covering the pellets by excess BPSCCO powder during sintering and formation of the 2223 phase was observed to be enhanced. Formation of low temperature eutectic by silver addition was observed to accelerate the rate of evaporation. Lower temperature processing was required for fabrication of high quality Ag sheathed BPSCCO tapes. (C) 1999 Kluwer Academic Publishers.

Patrabansh, S; Madan, M, Mineral content of the fruiting bodies of Pleurotus sajor-caju (FR.) Singer cultivated on different kinds of biomass Source: ACTA BIOTECHNOLOGICA, WILEY-V C H VERLAG GMBH, Vol.19.00 Issue. 2 pp.101-109 1999.

Abstract: Pleurotus sajor-caju (FR.) SINGER was cultivated on different organic wastes, namely sericulture waste, Populus deltoides MARSH and Eupatorium adenophorum SPRENG. Paddy straw was taken as the control and all the data were compared with it. The mineral contents of the fruiting bodies of Pleurotus sajor-caju and the substrates on which the mushroom was grown were analyzed. Among the eight minerals determined (calcium, phosphorus, potassium, magnesium, sodium, iron, manganese and zinc), the potassium content was highest followed by phosphorus, magnesium and sodium. Analysis of the mineral contents of the substrates before cultivation had also been carried out. The mineral contents of the fruiting bodies of Pleurotus sajor-caju were found to be different on different substrates. It was also observed that the mineral contents of the fruiting bodies of Pleurotus sajor-caju increase when cultivated on substrates with higher mineral contents. The maximum mineral contents per 100 g of the substrates before cultivation were Ca - 347 mg; P - 151 mg; K - 1,805 mg; Na - 127 mg; Mg - 227 mg; Fe - 53 mg; Mn - 10 mg and Zn - 3.1 mg. The mineral contents of the fruiting bodies of Pleurotus sajor-caju per 100 g ranged as follows: Ca - 25.1 mg to 35.3 mg; P - 448 mg to 602 mg; K - 2,146 mg to 2350 mg; Na - 139 mg to 229 mg; Mg - 153 mg to 224 mg; Fe - 9.74 mg to 20.75 mg; Mn - 2.5 mg to 4.0 mg and Zn - 2.2 mg to 3.1 mg.

Patri, VS; Kumar, MJ, Novel Ge-profile design for high-speed SiGe HBTs: modelling and analysis Source: IEE PROCEEDINGS-CIRCUITS DEVICES AND SYSTEMS, IEE-INST ELEC ENG, Vol.146.00 Issue. 5 pp.291-296 1999.

Abstract: The authors investigate the optimisation of the Ge profile in SiGe HBTs, with the aim of enhancing current gain without degrading the base transit time at different ambient temperatures and points of film stability. Using a new box-triangular Ge profile, they show that a current gain enhancement of similar to 3 is achievable at T = 300K for y(tot) = 14% Ge without degrading the base transit time corresponding to that of a triangular Ge profile. The effect of an electric field on the base transit time is also studied. It is shown that for I W-B = 50nm, the limiting base electric field is similar to 40kV/cm, beyond which any reduction in the base transit time is offset by the electron mobility degradation.

Paul, R; Dutta, B; Bhattacharya, S; Mitra, AP; Lal, M, Kyoto agreement on greenhouse gas reduction and future global temperature and sea-level trends Source: CURRENT SCIENCE, CURRENT SCIENCE ASSN, Vol.76.00 Issue. 8 pp.1069-1071 1999.

Abstract:

Prabhakaran, A; Jagga, CR, Condition monitoring of steam turbine-generator through contamination analysis of used lubricating oil Source: TRIBOLOGY INTERNATIONAL, ELSEVIER SCI LTD, Vol.32.00 Issue. 3 pp.145-152 1999.

Abstract: The objective of this paper is to present a systematic analysis of wear particles contained in used lubricant of steam turbine-generator of a thermal power station. The turbogenerator was condition-monitored over a period of two years through wear debris and particulate contamination analysis of the oil. Various sophisticated techniques such as automatic particle counter, ferrography, inductively coupled plasma atomic emission spectrometry (ICPAES), scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDAX) have been employed to extract the relevant information about the health of the machine. Eventually, a correlation of different techniques of wear debris monitoring on the basis of current investigation ascertains the significance of the collective approach of various techniques to avoid catastrophic breakdowns and expensive component replacements. (C) 1999 Elsevier Science Ltd. All rights reserved.

Pradhan, BK; Sandle, NK, Effect of different oxidizing agent treatments on the surface properties of activated carbons Source: CARBON, PERGAMON-ELSEVIER SCIENCE LTD, Vol.37.00 Issue. 8 pp.1323-1332 1999.

Abstract: Two commercially available activated carbon (activated charcoal cloth (ACC) and activated granular carbon(AGC)) were oxidized with different oxidizing agents viz., HNO3, H2O2 and (NH4)(2)S2O8, in order to introduce surface oxygen complexes. The effect of the oxidizing agent treatment on the surface chemical nature and surface texture were characterized by ultimate elemental analysis, bulk chemical analysis, FTIR, XRD and nitrogen adsorption isotherms studies. FTIR shows carboxylic groups were essentially fixed along with ketone and ether groups after the treatment of the oxidizing agents. The HNO3 treatment affects the surface area and the porosity of the samples to a greater extent than the others. The micropore values calculated from DR and alpha(s) methods reveals that 70% of the adsorption capacity of activated carbons is due to the micropore present. (C) 1999 Elsevier Science Ltd. All rights reserved.

Prakash, B; Bandyopadhyay, S; Mukerji, J, Friction coefficient of (alpha+beta)-SiAlON composite against a steel and dense silicon nitride tribopair Source: JOURNAL OF THE AMERICAN CERAMIC SOCIETY, AMER CERAMIC SOC, Vol.82.00 Issue. 8 pp.2255-2256 1999.

Abstract: The friction characteristics of hot-pressed (alpha+beta)-SiAlON, versus those of bearing steel and dense Si3N4 under dry sliding conditions, are reported. The coefficient of friction decreases as the alpha-SiAlON content increases and is double that of a metal-ceramic pair, in comparison to that of a ceramic-ceramic pair.

Prakash, O; Pandey, RK, Failure analysis of fuel injection tubes Source: ENGINEERING FAILURE ANALYSIS, PERGAMON-ELSEVIER SCIENCE LTD, Vol.6.00 Issue. 1 pp.43-55 1999.

Abstract: Failures in the bent portion of the fuel injection tubes from a certain lot were reported under a working pressure of 112 MPa. Investigations were carried out to determine the cause of failure. Hardness tests revealed improper stress relieving after bending of failed tubes. Chemical analysis showed higher than prescribed carbon content in failed tubes. Inhomogeneity in microstructure and lack of proper stress relieving facilitated the cracking. Cracking proceeded typically in a brittle manner along the grain boundaries. Observation of striations on the fracture surface under SEM confirmed fatigue to be the damage mechanism. (C) 1998 Elsevier Science Ltd. All rights reserved.

Pring, A; Kolitsch, U; Birch, WD; Beyer, BD; Elliott, P; Ayyappan, P; Ramanan, A, Bariosincosite, a new hydrated barium vanadium phosphate, from the Spring Creek Mine, South Australia Source: MINERALOGICAL MAGAZINE, MINERALOGICAL SOCIETY, Vol.63.00 Issue. 5 pp.735-741 1999.

Abstract: Bariosincosite is a new barium vanadium phosphate hydrate from the Spring Creek Mine, near Wilmington, South Australia. The new mineral occurs as irregular clusters of pale green, very thin platey crystals up to 250 mu m across and 2 to 5 mu m thick. The tetragonal crystals are tabular on {001} and the other form present is {100}. Associated with bariosincosite are quartz, cuprite, native copper, fluorapatite, whitlockite, baryte and springcreekite, BaV33+(PO4)(2)(OH,H2O)(6). Bariosincosite appears to have formed under supergene or low-temperature late-stage hydrothermal conditions. Electron microprobe analysis yielded: BaO 23.20; SrO 4.19; CaO 0.36; VO2 31.55; Fe2O3 0.20; Al2O3 0.50; P2O5 28.15; H2O 13.93 (calculated). These data give an empirical formula of (Ba0.77Sr0.20Ca0.03)(Sigma 1.00)[(V0.964+Al0.03Fe0.013+)(Sigma 1.00)O(PO4)](2). 4H(2)O calculated on the basis of two P atoms. The simplified formula is Ba(V4+OPO4)(2). 4H(2)O. The mineral is transparent with a very pale green streak, a vitreous lustre and an estimated Mohs hardness of 3. The strongest lines in the X-ray powder pattern are [d(obs) (I-obs) (hkl)] 6.414 (20) (110, 002); 5.748 (70) (111); 4.552 (30) (112. 200); 3.195 (20) (220, 004); 3.100 (100) (203, 221); 2.847 (40) (222, 114); 2.786 (80) (311); 2.365 (30) (313, 115); and 2.017 (100) (420, 332, 116). These data were indexed on a tetragonal cell, with a = 9.031(6), c = 12.755(8) Angstrom and V = 1040(1) Angstrom(3); the space group is probably P4/n or P4/nmm. For Z=4 and using the empirical formula, the calculated density is 3.306 gm/cm(3). Bariosincosite is uniaxial negative with omega = 1.721(2) and epsilon = 1.715(2) (white light); pleochroism is weak from colourless (E) to pale green (O), absorption O > E. The mineral is named for the relationship to sincosite, Ca(V4+OPO4)(2). 4H(2)O.

Puri, S; Dubey, RK; Bhalotra, A; Puri, BK, Differential-pulse polarographic determination of tin (II) and lead (II) in various standard alloys, standard biological materials and environmental samples after adsorption of their quinolin-8-olates on to microcrystalline naphthalene. Source: ANNALI DI CHIMICA, SOC CHIMICA ITALIANA, Vol.89.00 Issue. 12-Nov pp.925-936 1999.

Abstract: The quinolin-8-olates of tin(II) and lead(II) are quantitatively adsorbed on to microcrystalline naphthalene in the pH range 2.0-9.0 and 8.8-11.7 respectively. After filtration, the metal complexes have been desorbed by shaking with HCl and metal ions determined with a differential-pulse polarograph. Dissolved oxygen has been removed by adding a few mls of 4 % NaBH4 in the case of lead. The detection limits are 0.15 ppm for lead and 0.10 ppm for tin at the minimum instrumental settings (signal to noise ratio = 2). Linearity is maintained in the concentration ranges 0.50-13.0 for lead and 0.6-10.0 ppm for tin with correlation factors of 0.9997 and 0.9994, and relative standard deviations of 0.95 and 1.1 % respectively. The characterization of the electroactive process included an examination of the degree of reversibility. Various parameters such as the effect of pH, volume of aqueous phase, reagent and naphthalene concentrations and the interference of a large number of metal ions and anions on the determination of these metals have been studied in detail to optimize the conditions for their trace determination in various standard alloys, standard biological materials and environmental samples. The method is found to be highly selective, sensitive, rapid and economical.

Rahman, SA; Jayadeva; Roy, SCD, Neural network approach to graph colouring Source: ELECTRONICS LETTERS, IEE-INST ELEC ENG, Vol.35.00 Issue. 14 pp.1173-1175 1999.

Abstract: A neural network for colouring a graph of N nodes is proposed which uses only N neurons and N-2 weights. In contrast, N-2 neurons and N-4 interconnections are required by Hopfield net based approaches. Experiments with a breadboard realisation using discrete components yielded promising results.

Rajagopalan, T; Reddy, GB, Effect of annealing rate on the crystallization process in Ge5Bi18Se77 films Source: THIN SOLID FILMS, ELSEVIER SCIENCE SA, Vol.353.00 Issue. 2-Jan pp.254-258 1999.

Abstract: Amorphous Ge5Bi18Se77 thin films deposited by thermal evaporation were crystallized by thermal annealing at their crystallization temperature (T-c). The composition, determined using EDAX, does not indicate any significant variation in both as-deposited films and films annealed with different annealing rates from that of bulk alloy. The effect of annealing rate on the nature and the degree of crystallization has been investigated by studying the structure using TEM/XRD and the surface morphology using SEM. It is found that the annealed films crystallized into a face centred cubic (FCC) phase with a lattice constant of 6.2084 +/- 0.0015 Angstrom. Further, it is also seen that depending on the annealing rate, the as-deposited films crystallized into either single crystal films or polycrystalline films. A detailed analysis of the structural properties has been presented. (C) 1999 Elsevier Science S.A. All rights reserved.

Rajpal, N; Chaudhury, S; Banerjee, S, Recognition of partially occluded objects using neural network based indexing Source: PATTERN RECOGNITION, PERGAMON-ELSEVIER SCIENCE LTD, Vol.32.00 Issue. 10 pp.1737-1749 1999.

Abstract: In this paper, a new neural network based indexing scheme has been proposed for recognition of planar shapes. Local contour segment-based-invariants have been used for indexing. Object contours have been obtained using a new algorithm which combines advantages of region growing and edge detection. Neighbourhood constraints have been applied on the results of indexing for combining hypotheses generated through the indexing scheme. Composite hypotheses have been verified using a distance transform based algorithm. Experimental results, on real images of varying complexity of a reasonably large database of objects have established the robustness of the method. (C) 1999 Pattern Recognition Society. Published by Elsevier Science Ltd. All rights reserved.

Ram, RN; Charles, I, Synthesis of 3-substituted and 2,3-disubstituted 4-chlorofurans Source: CHEMICAL COMMUNICATIONS, ROYAL SOC CHEMISTRY, Vol. Issue. 22 pp.2267-2268 1999.

Abstract: A simple method for the synthesis of 3-substituted and 2,3-disubstituted 4-chlorofurans is described which involves CuCl/bipy-catalysed regioselective cyclisation of 1-acetoxy-2,2,2-trichloroethyl allyl ethers followed successively by dechloroacetoxylation with Zn dust and tandem dehydrohalogenation-aromatisation with (BuOK)-O-t/18-crown-6.

Ramesh, KC; Sagar, R, Fabrication of metal matrix composite automotive parts Source: INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY, SPRINGER-VERLAG LONDON LTD, Vol.15.00 Issue. 2 pp.114-118 1999.

Abstract: Driven by the need to build lighter weight; quieter and more fuel-efficient engines, the automotive industry has recognised the need for materials substitution,offering outstanding properties in a number of engine components, including engine poppet valves. Since the values control the gas flow, valve size, timing and overlap, they all influence volumetric efficiency: The valve train is designed to achieve maximum volumetric efficiency at the desired level of engine performance. Also engine valves are subjected to high operating temperatures and stress conditions which affect durability. The application of finite element analysis resulting in a Weibull failure theory analysis is a valid tool in predicting the probability of failure of the valves. The present rt work envisages carrying out some studies on Al-SiC and Al-TiC composites as possible alternative materials for engine popper valves. The present trend to make par-ts at or near net shape has brought powder metallurgy (P,M) to the forefront and is being vigorously pursued by automotive design and materials engineers rr ho are finding an increased application for this energy and cost-saving process. Mixtures of four different compositions (15, 20, 25, 30% by weight) of SiC were prepared By the PM technique, valves were fabricated by placing these powder mixtures ill layers (one weight per cent along the stem and one along the base) in a die. Specimens (phi 15 x 30) were also prepared hy the PM technique so that properties like compressive, tensile strength, etc. could be studied. A die was fabricated to cast valves through a liquid metallurgy route.

Ramesh, KJ; Rao, PLS; Mohanty, UC, A study on the performance of the NCMRWF analysis and forecasting system during Asian summer monsoon: Thermodynamic aspects Source: PURE AND APPLIED GEOPHYSICS, BIRKHAUSER VERLAG AG, Vol.154.00 Issue. 1 pp.141-162 1999.

Abstract: The thermodynamic characteristics of the Asian summer monsoon are examined with a global analysis-forecast system. In this study, we investigated the large-scale balances of heat and moisture by making use of operational analyses as well as forecast fields for June, July and August (JJA), 1994. Apart from elucidating systematic errors in the temperature and moisture fields, the study expounds the influence of these errors on the large-scale budgets of heat and moisture over the monsoon region. The temperature forecasts of the model delineate predominant cooling in the middle and lower tropospheres over the monsoon region. Similarly, the moisture forecasts evince a drying tendency in the lower troposphere. However, certain sectors of moderate moistening exist over the peninsular India and adjoining oceanic sectors of the Arabian Sea and Bay of Bengal. The broad features of the large-scale heat and moisture budgets represented by the analysis/forecast fields indicate good agreement with the observed aspects of the summer monsoon circulation. The model forecasts fail to retain the analyzed atmospheric variability in terms of the mean circulation, which is indicated by underestimation of various terms of heat and moisture budgets with an increase in the forecast period. Further, the forecasts depict an anomalous diabatic cooling layer in the lower middle troposphere of the monsoon region which inhibits vertical transfer of heat and moisture from the mixed layer of the atmospheric boundary layer to the middle troposphere. In effect, the monsoon circulation is considerably weakened with an increase in the forecast period. The treatment of shallow convection and the use of interactive clouds in the model can reduce the cooling bias considerably.

Rana, SK, Some studies on fibrillation of drawn tapes made from high-density polyethylene blended with small amounts of linear low-density polyethylene Source: INDIAN JOURNAL OF FIBRE & TEXTILE RESEARCH, NATL INST SCIENCE COMMUNICATION, Vol.24.00 Issue. 3 pp.145-148 1999.

Abstract: Tapes of high-density polyethylene (HDPE) and HDPE blends having 3-5% by weight linear low-density polyethylene (LLDPE) were prepared by first extruding them from the melt on an extruder and then drawing the extruded tapes on a hot plate. The tensile properties of the tapes were studied on an Instron tensile tester while the fibrillation characteristics were investigated with the help of Goodbrand twist fibrillator. The tapes were etched in chlorosulphonic acid and the etched tapes were examined on scanning electron microscope. A significant improvement in resistance to fibrillation was observed for the tape prepared from blend having 5% by weight of LLDPE. The improvement in resistance to fibrillation has been attributed to the observed increase in the branching of the fibrils in the drawn tapes which is apparently due to the incorporation of the second component.

Rao, JS; Yu, YD; Shiau, TN, Transient response of rotating laminated plates with interfacial friction under accelerating conditions Source: JOURNAL OF SOUND AND VIBRATION, ACADEMIC PRESS LTD, Vol.228.00 Issue. 1 pp.37-50 1999.

Abstract: This paper is concerned with laminated plates mounted on a rotating disk under accelerating conditions. Interfacial friction is included at specified locations on the plate. The effects of in-plane loads and non-linear Coriolis forces are included. An eight noded isoparametric element is derived for the analysis. Under the action of combined accelerating conditions and Coriolis forces, it is shown that the blade is subjected to shock forces. Employing the Newmark direct integration method, the results obtained are presented. (C) 1999 Academic Press.

Rao, KS; Kumar, AN, Toughness degradation during fabrication of API X42 and X60 grade pipeline Source: TRANSACTIONS OF THE INDIAN INSTITUTE OF METALS, INDIAN INST METALS, Vol.52.00 Issue. 4 pp.227-234 1999.

Abstract: Two fabrication steps in the manufacture of pipelines, namely cold bending and welding are identified for the significant deterioration of the steel plates used. In X60 grade around 57% and 40% loss in CTOD toughness are accounted for welding and bending respectively. However, a combined effect of the two results in 80% loss. In X42 grade, the toughness is measured by impact energy which is reduced significantly from 78.5 J (unweld) to 35 J due to welding. Microstructural and microfractographic results are used to justify the various toughness values in the parent mental, weld zone and heat affected zone in X42 grade. The orientation of pearlite banding as observed on fracture plane with respect to notch front and applied loading direction appears to have strong influence on the shape, size and morphology of the dimples and the corresponding toughness values.

Ravi, N; Mohanty, UC; Madan, OP; Paliwal, RK, Forecasting of thunderstorms in the pre-monsoon season at Delhi Source: METEOROLOGICAL APPLICATIONS, CAMBRIDGE UNIV PRESS, Vol.6.00 Issue. 1 pp.29-38 1999.

Abstract: Accurate prediction of thunderstorms during the pre-monsoon season (April-June) in India is essential for human activities such as construction, aviation and agriculture. Two objective forecasting methods are developed using data from May and June for 1985-89. The developed methods are tested with independent data sets Of the recent years, namely May and June for the years 1994 and 1995. The first method is based on a graphical technique. Fifteen different types of stability index are used in combinations of different pairs. It is found that Showalter index versus Totals total index and Jefferson's modified index versus George index can cluster cases of occurrence of thunderstorms mixed with a few cases of non-occurrence along a zone. The zones are demarcated and further sub-zones are created for clarity. The probability of occurrence/non-occurrence of thunderstorms in each sub-zone is then calculated. The second approach uses a multiple regression method to predict the occurrence/non-occurrence of thunderstorms. A total of 274 potential predictors are subjected to stepwise screening and nine significant predictors are selected to formulate a multiple regression equation that gives the forecast in probabilistic terms. Out of the two methods tested, it is found that the multiple regression method gives consistently better results with developmental as well as independent data sets; it is a potential method for operational use.

Ravi, TV; Gowda, KC, Clustering of symbolic objects using gravitational approach Source: IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART B-CYBERNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Vol.29.00 Issue. 6 pp.888-894 1999.

Abstract: Most of the techniques used in the literature in clustering symbolic data are based on the hierarchical methodology, which uses the concept of agglomeration or division as the core of the algorithm. The main contribution of this paper is to formulate a clustering algorithm for symbolic objects based on the gravitational approach. The proposed procedure is based an the physical phenomenon in which a system of particles in space converge to the centroid of the system due to gravitational attraction between the particles. Some pairs of samples called as mutual pairs, which have a tendency to gravitate toward each other, are discerned at each stage of this multistage scheme. The notions of cluster coglomerate strength and global coglomerate strength are used for accomplishing or abandoning the process of merging a mutual pair. The methodology forms composite symbolic objects whenever two symbolic objects are merged. The process of merging at each stage, reduces the number of samples that are available for consideration, The procedure terminates at some stage where there are no more mutual pairs available for merging. The efficacy of the proposed methodology is examined by applying it on numeric data and also on data sets drawn from the domain of fat oil, microcomputers, microprocessors, and botany. A detailed comparative study is carried out with other methods and the results are presented.

Ravi, TV; Gowda, KC, An ISODATA clustering procedure for symbolic objects using a distributed genetic algorithm Source: PATTERN RECOGNITION LETTERS, ELSEVIER SCIENCE BV, Vol.20.00 Issue. 7 pp.659-666 1999.

Abstract: A novel ISODATA clustering procedure for symbolic objects is presented using distributed genetic algorithms where in a structured organisation in the distribution of the population is introduced and selection and mating are made within locally distributed subgroups of individuals rather than the whole population. (C) 1999 Elsevier Science B.V. All rights reserved.

Ravikumar, CP; Saund, GS; Agrawal, N, A functional-level testability measure for register-level circuits and its estimation Source: MICROPROCESSORS AND MICROSYSTEMS, ELSEVIER SCIENCE BV, Vol.22.00 Issue. 9 pp.535-542 1999.

Abstract: Estimation of circuit testability is an important issue when evaluating the circuit design. A testability measure indicates how easy or difficult it would be to generate tests for the circuit. STAFAN (Statistical Fault Analysis) is a well known gate-level testability analysis program which predicts the fault coverage of a digital circuit under the stuck-at fault model, without actually performing fault simulation. STAFAN offers speed advantage over other testability analysis programs such as SCOAP; further, it explicitly predicts the fault coverage for a given test set, unlike other testability measures which are harder to interpret. We show how a STAFAN-like testability analysis program can be constructed for circuits built out of register-level modules such as adders, multipliers, multiplexers, and busses. Our tool, which we call FSTAFAN, is useful in a testability-driven high-level synthesis environment. We have implemented FSTAFAN on a Sun/SPARC workstation and describe its performance on some register-level circuits. (C) 1999 Elsevier Science B.V. All rights reserved.

Ravindran, TR; Arora, AK; Balamurugan, B; Mehta, BR, Inhomogeneous broadening in the photoluminescence spectrum of CdS nanoparticles Source: NANOSTRUCTURED MATERIALS, PERGAMON-ELSEVIER SCIENCE LTD, Vol.11.00 Issue. 5 pp.603-609 1999.

Abstract: The effect of particle size distribution of CdS nanoparticles on the band-edge photoluminescence (PL) spectrum is investigated. The resulting inhomogeneously broadened lineshape is found to be asymmetric and depend on the width of particle size distribution. The calculated lineshape is fitted to the measured PL spectrum of 3.6 nm diameter CdS nanoparticles, which showed the band-edge PL peak around 3.00 eV and that due to recombination at defects at 2.56 eV. The parameters of the PL spectrum of a bulk CdS film are used as inputs for the fitting. The average panicle size and the standard deviation of the size distribution are obtained from the analysis. The particle size estimated from the PL data is compared with that obtained from x-ray diffraction measurements. (C)1999 Acta Metallurgica Inc.

Reddy, KS; Avanti, P; Kaushika, ND, Finite time thermal analysis of ground integrated-collector-storage solar water heater with transparent insulation cover Source: INTERNATIONAL JOURNAL OF ENERGY RESEARCH, JOHN WILEY & SONS LTD, Vol.23.00 Issue. 11 pp.925-940 1999.

Abstract: A transparent honeycomb insulated ground integrated-collector-storage system has been investigated for the engineering design and solar thermal performance. The system consists of a network of pipes embedded in a concrete slab whose surface is blackened and covered with transparent insulation materials (TIM) and the bottom is insulated by the ground. Heat may be retrieved by the flow of fluid through the pipe. A simulation model has been developed; it involves the solution of the two-dimensional transient heat conduction equation using an explicit finite-difference scheme. Computational results have been used to determine the effect of such governing parameters as depth as well as pitch of the pipe network and collector material on the thermal performance of the system. The pipe network depth of 10 cm and the TIM cover made of 5 cm compounded honeycomb seem suitable for the proposed system. Solar gain (solar collection efficiency of 30-50% corresponding to collection temperature of 40-60 degrees C) and the diurnal heat storage characteristics of the system are found to be of the right order of magnitude for solar water heating applications. Copyright (C) 1999 John Wiley & Sons, Ltd.

Reddy, KS; Kaushika, ND, Comparative study of transparent insulation materials cover systems for integrated-collector-storage solar water heaters Source: SOLAR ENERGY MATERIALS AND SOLAR CELLS, ELSEVIER SCIENCE BV, Vol.58.00 Issue. 4 pp.431-446 1999.

Abstract: The thermal performance of transparently insulated integrated-collector-storage solar water heaters is investigated theoretically as well as experimentally for a comparative study of cover systems having transparent insulation materials devices placed between the top glazing and the absorber. The data on solar transmittance, heat loss reduction characteristics and solar collector-storage efficiencies of various configurations is generated for the system performance comparisons. These hot water systems exhibit average (diurnal basis) solar collection and storage efficiencies in the range of 20-40% at a collection temperature of 40-50 degrees C. The performance of water heaters with cover system having absorber-perpendicular configuration of TIM excel over absorber-parallel TIM covers. The effect of variation in the temperature of heat collected and cost of cover systems on the performance comparisons is also discussed. (C) 1999 Elsevier Science B.V. All rights reserved.

Rengasamy, RS; Sengupta, AK; Kothari, VK, Blend irregularity of air-jet textured yarns Source: INDIAN JOURNAL OF FIBRE & TEXTILE RESEARCH, NATL INST SCIENCE COMMUNICATION, Vol.24.00 Issue. 4 pp.233-241 1999.

Abstract: A quantitative analysis of the blend irregularity of air-jet textured yarns is reported. The effects of raw material and process and nozzle parameters on the blend intimacy of air-jet textured yarns in a rotational pattern have been studied for the different blends of filament yarns. It has been established that the index of blend irregularity is closely associated with thr yam tension levels at the exit of the nozzle and in the mechanical stabilizing zone. Components of dissimilar fibre characteristics result in poor blend intimacy. Texturing in wet condition improves the blend intimacy. Blend regularity is influenced by the combination of type of texturing jet and raw materials used.

Roy, I; Pai, A; Lali, A; Gupta, MN, Comparison of batch, packed bed and expanded bed purification of A-niger cellulase using cellulose beads Source: BIOSEPARATION, KLUWER ACADEMIC PUBL, Vol.8.00 Issue. 6 pp.317-326 1999.

Abstract: Rigid macroporous cross-linked cellulose beads were prepared and used as a useful affinity medium for purification of A. niger cellulase from commercial preparation, in batch; packed bed and expanded bed modes. The beads bound 99% activity in both packed bed and expanded bed modes and upto 91% activity could be recovered by washing the adsorbent with 1 M phosphate buffer, pH 7.0. While batch adsorption and elution gave only 4-fold purification, packed bed operation gave 14-fold purification and expanded bed, the highest, 36-fold purification.

Roy, S, An approach to configure optimal cogeneration system between existing steam headers of an industry Source: INTERNATIONAL JOURNAL OF ENERGY RESEARCH, JOHN WILEY & SONS LTD, Vol.23.00 Issue. 7 pp.625-635 1999.

Abstract: Traditionally, steam-based cogeneration systems have been added to industrial applications as topping cycle or bottoming cycle configurations. Such systems frequently require that pressure or steam flow handling capacity of one or more existing steam headers be enhanced. The aim of this work is to suggest a new type of cogeneration system configuration (referred to as the closed-loop configuration) that essentially avoids any such requirement of capacity enhancement. Considerable difference in enthalpy between existing steam headers is a feature commonly observed in large industrial setups. Transfer of steam between two such headers can be configured so as to cogenerate significant quantities of electric power, that may either be used in-plant or may be sold to local utilities at an appropriate price. This paper presents a design approach to optimally configure such cogeneration systems. Case studies illustrate application of the design approach to benchmark oil refinery plants. Copyright (C) 1999 John Wiley & Sons, Ltd.

Roy, S, Influence of amortisseurs on stabiliser design requirements for damping local oscillations of a generator Source: IEEE TRANSACTIONS ON POWER SYSTEMS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Vol.14.00 Issue. 3 pp.935-942 1999.

Abstract: This paper introduces a new small perturbation model for the well known "generator/infinite-bus" system, that includes explicit representation of amortisseur windings. The major points of difference between this model and the conventional Heffron-Phillips small perturbation model are discussed by a comparison of synchronising and damping torque coefficients obtained from them. The design and tuning requirements of a conventional generator power system stabiliser (PSS), principally intended to damp out local oscillations, are reconsidered to accommodate amortisseur effects as reflected in the new generator model. It is shown that the PSS transfer function may now assume a different generic form, as well as a different set of compensatory time-constants.

Roychoudhury, PK; Gomes, J; Bhattacharyay, SK; Abdulah, N, Production of urokinase by HT 1080 human kidney cell line Source: ARTIFICIAL CELLS BLOOD SUBSTITUTES AND IMMOBILIZATION BIOTECHNOLOGY, MARCEL DEKKER INC, Vol.27.00 Issue. 6-May pp.399-402 1999.

Abstract: Studies were carried out in T-flasks and bioreactor to produce urokinase enzyme using HT 1080 human kidney cell line. While growing the cell line it has been observed that the lag phase is reduced considerably in the bioreactor as compared to T-flask culture. The HT 1080 cell adhesion rate and urokinase production were observed to be the function of serum concentration in the medium. The maximum urokinase activity of 3.1 x 10(-4) unit ml(-1) was achieved in the bioreactor at around 65 h of batch culture. Since HT 1080 is an anchorage dependent cell line, therefore, the hydrodynamic effects on the cell line were investigated.

Saha, SK, Dynamics of serial multibody systems using the decoupled natural orthogonal complement matrices Source: JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME, ASME-AMER SOC MECHANICAL ENG, Vol.66.00 Issue. 4 pp.986-996 1999.

Abstract: Constrained dynamic equations of motion of serial multibody systems consisting of rigid bodies in a serial kinematic chain are derived in this paper First, the Newton-Euler equations of motion of the decoupled rigid bodies of the system at hand are written. Then, with the aid of the decoupled natural orthogonal complement (DeNOC) matrices associated with the velocity constraints of the connecting bodies, the Euler-Lagrange independent equations of motion are derived. The De NOC is essentially the decoupled form of the natural orthogonal complement (NOC) matrix, introduced elsewhere. Whereas the use of the latter provides recursive order n-n being the degrees-of-freedom of the system at hand-inverse dynamics and order n(3) forward dynamics algorithms, respectively, the former leads to recursive order n algorithms for both the cases. The order n algorithms are desirable not only for their computational efficiency but also for their numerical stability, particularly, in forward dynamics and simulation, where the system's accelerations are solved from the dynamic equations of motion and subsequently integrated numerically. The algorithms are illustrated with re three-link three-degrees-of-freedom planar manipulator and a six-degrees-of-freedom Stanford arm.

Saha, SK, Analytical expression for the inverted inertia matrix of serial robots Source: INTERNATIONAL JOURNAL OF ROBOTICS RESEARCH, SAGE PUBLICATIONS INC, Vol.18.00 Issue. 1 pp.116-124 1999.

Abstract: This paper presents the analytical derivation of the inertia matrix and its inverse for an open-loop, serial-chain robot. The derivation allows one to write a recursive forward-dynamics algorithm for simulation purposes whose computational complexity is of order n, i.e., O(n)-n being the degrees of freedom of the robot under study. The proposed methodology is based on the Gaussian elimination of the inertia matrix, in contrast to, say Kalman filtering, which is proposed elsewhere. The derivation is illustrated with a three-degrees-of-freedom planar robot.

Salhotra, KR; Chattopadhyay, R; Kaushik, RCD; Dhamija, S, Twist structure of friction spun yarns Source: JOURNAL OF THE TEXTILE INSTITUTE, TEXTILE INST INTL HEADQUARTERS, Vol.90.00 Issue. 4 pp.637-642 1999.

Abstract:

Salhotra, KR; Dhamija, S; Arora, V, Determination of twist loss in rotor-spun yarns Source: INDIAN JOURNAL OF FIBRE & TEXTILE RESEARCH, NATL INST SCIENCE COMMUNICATION, Vol.24.00 Issue. 1 pp.27-33 1999.

Abstract: The yam twist of OE rotor-spun yams has been measured by three different methods, viz. detwist-retwist, twist-to-break and optical. The optical method, based on tracer fibre technique, has been found to be the most reliable and it gives values which are nearer to the mechanical twist. The twist value by this method, called real twist, shows the highest correlation with the nominal twist and correlates well with the values given by the other two methods. Obviously, it shows highest twist values and minimum twist loss. The twist loss increases significantly with the use of grooved nozzle and increase in tex twist factor but decreases with the increase in opening roller speed. Finer yams exhibit considerably higher real twist loss, whereas increasing rotor speed initially decreases the twist loss followed by an upward trend. The apparent twist losses given by the other two methods depict different trends from real twist loss.

Sambandan, G; Tripathi, VK; Parashar, J; Bharuthram, R, Nonlinear interaction of a high-power electromagnetic beam in a dusty plasma: Two-dimensional effects Source: PHYSICS OF PLASMAS, AMER INST PHYSICS, Vol.6.00 Issue. 3 pp.762-766 1999.

Abstract: A large-amplitude Gaussian electromagnetic beam, propagating through a dusty plasma, heats the electrons nonuniformly. As the electron temperature rises, the rate of electron attachment to dust particles changes, modifying dust charge and free electron density. Further, the ambipolar diffusion of the plasma under thermal pressure gradient creates a plasma channel that guides the electromagnetic beam. At powers exceeding a threshold value, the beam becomes self-focused. (C) 1999 American Institute of Physics. [S1070-664X(99)00503-0].

Sambandan, G; Tripathi, VK; Sayal, VK, Rayleigh-Taylor mode-RF coupling in a dusty plasma Source: PHYSICS LETTERS A, ELSEVIER SCIENCE BV, Vol.262.00 Issue. 3-Feb pp.179-185 1999.

Abstract: The growth rate of a gravity or curvature drift driven Rayleigh-Taylor (R-T) mode in a dusty plasma is adversely affected by the dust particles, through dust charge fluctuations. When a high-power radio wave (rf) is launched into the plasma, it couples with the R-T mode to produce high-frequency side bands. The latter couple with the rf pump to heat the electrons at the frequency of the R-T mode. The pressure-gradient force thus generated, drives the R-T mode more unstable, with large growth rate. The growth rate is significantly modified by the presence of charged dust particles and its charge fluctuations caused by the low frequency perturbations. The threshold effective radiated power for the suppression of the mode increases with decreasing theta, being the angle between the wave vectors of the incident rf wave and the R-T mode. The growth rates of the R-T mode with high-frequency radio waves with typical parameters of the F-region of the ionosphere is obtained. (C) 1999 Elsevier Science B.V. All rights reserved.

Sanjeev, K; Tiwari, GN, Optimization of daily yield for an active double effect distillation with water flow Source: ENERGY CONVERSION AND MANAGEMENT, PERGAMON-ELSEVIER SCIENCE LTD, Vol.40.00 Issue. 7 pp.703-715 1999.

Abstract: In this communication, an attempt has been made to develop a theoretical model for prediction of the daily yield from an active double effect distillation system. In this case, the latent heat of condensation is utilized for further distillation by flowing water over the first condensing cover. The effects of collector area, flow rate, basin area, water depth etc, on daily yield have been presented for a typical day of Delhi climate conditions. Further, the developed computer model has been used to optimise the daily yield for a given set of parameters, namely basin area, water depth, collector area etc. (C) 1999 Elsevier Science Ltd. All rights reserved.

Satyanarayana, ANV; Mohanty, UC; Sam, NV, A study on the characteristics of the marine boundary layer over Indian Ocean with ORV Sagar Kanya cruise # 120 during 1997 Source: CURRENT SCIENCE, CURRENT SCIENCE ASSN, Vol.76.00 Issue. 7 pp.890-897 1999.

Abstract: The CLASS system observations of wind speed, wind direction, temperature and moisture at different pressure levels taken during the pre-INDOEX (Indian Ocean Experiment) cruise # 120 were used for the study, This article presents a study of marine boundary layer (MBL) characteristics, such as turbulent kinetic energy, MBL height, eddy diffusivity, etc, over the Indian Ocean using a multilevel one-dimensional PBL model with one and a half order TKE-epsilon closure scheme, The model also generates the vertical profiles of zonal wind, meridional wind, potential temperature and specific humidity. The model simulations are compared with the observations and the statistical analysis, viz, correlation coefficient; the RMS error is found to be satisfactory.

Selvakumaran, TV; Rajan, BS, Block-coded modulation using two-level group codes over generalized quaternion groups Source: IEEE TRANSACTIONS ON INFORMATION THEORY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Vol.45.00 Issue. 1 pp.365-372 1999.

Abstract: A length a group code over a group G is a subgroup of G(n) under component-wise group operation. Two-level group codes over the class of generalized quaternion groups, Q(2m) m greater than or equal to 3, are constructed using a binary code and a code over Z(2m-1), the ring of integers module 2(m-1), as component codes and a mapping f from Z(2) X Z(2m-1) to Q2m. A set of necessary and sufficient conditions on the component codes is derived which will give group codes over Q(2m). Given the generator matrices of the component codes, the computational effort involved in checking the necessary and sufficient conditions is discussed. Starting from a four-dimensional signal set matched to Q(2m), it is shown that the Euclidean space codes obtained from the group codes over Q(2m) have Euclidean distance profiles which are independent of the coset representative selection involved in f. A closed-form expression for the minimum Euclidean distance of the resulting group codes over Q(2m) is obtained in terms of the Euclidean distances of the component codes. Finally, it is shown that all four-dimensional signal sets matched to Q(2m) have the same Euclidean distance profile and hence the Euclidean space codes corresponding to each signal set for a given group code over Q(2m) are automorphic Euclidean distance equivalent.

Shahabuddin, G; Terborgh, JW, Frugivorous butterflies in Venezuelan forest fragments: abundance, diversity and the effects of isolation Source: JOURNAL OF TROPICAL ECOLOGY, CAMBRIDGE UNIV PRESS, Vol.15.00 Issue. pp.703-722 1999.

Abstract: Frugivorous butterflies were studied in a set of forested islands (0.1 to 1.15 ha) in a reservoir in eastern Venezuela to investigate the effects of fragmentation and the resulting isolation on their abundance, diversity and species composition. While some islands showed reduced abundance and species diversity in comparison to unfragmented (or control) sites, others did not. Isolation status affected both butterfly abundance and diversity. Islands located close to their colonizing sources (0.1-1 km) tended to support similar densities of butterflies but lower numbers of species in comparison to control sites. Far fragments (1-3 km from their colonizing sources) tended to harbour lower butterfly densities in comparison to control sites but undiminished numbers of species. Species composition varied significantly between control sites and islands and amongst control sites, near islands and far islands. Interspecific differences were observed in species' responses to fragmentation. Charaxines, medium-sized satyrines, morphines and brassolines may be vulnerable to extinction after habitat fragmentation while small-sized satyrines may be relatively resistant. Observations during the dry season indicate that butterfly species may exist as mainland-island metapopulations in Lago Curl, in which small habitat fragments require recolonization every year from source populations in large islands and mainland habitat.

Shaji, C; Bahulayan, N; Dube, SK; Rao, AD, A multi-level adaptation model of circulation for the western Indian Ocean Source: INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, JOHN WILEY & SONS LTD, Vol.31.00 Issue. 8 pp.1221-1264 1999.

Abstract: A three-dimensional, fully non-linear semi-diagnostic (adaptation) model is described. This model is used to compute the climatological mean circulation and to understand the role of local, steady forcing of the wind and thermohaline forcing on the observed circulation in the western tropical Indian Ocean. The model consists of equations of motion and continuity, sea surface topography, equations of state and temperature, and salinity diffusion equations. While the sea surface topography equation is solved by a successive overrelaxation technique, the other model equations are solved by a leap-frog numerical scheme. Two versions of the model, having 18 and 33 levels in the vertical direction, were prepared to study climatological mean circulation in the western tropical Indian Ocean. The first numerical experiment is carried out with the 18-level adaptation model to study the sensitivity of the solution to different values of eddy coefficients. The main scientific rationale behind these numerical experiments was to obtain the most appropriate values of the eddy coefficients for the realistic computation of climatological circulation in the western tropical Indian Ocean. Three numerical experiments were conducted for the month of February to understand the sensitivity of the model solution to different eddy coefficients. The model reproduced the circulation features during February, even with low values of horizontal and vertical eddy coefficients. In the second experiment, the adaptation model, with 33 levels in the vertical direction, is applied to study the seasonal mean climatological circulation at selected depths during Spring in the western tropical Indian Ocean. Adapted (steady state) results of currents, sea surface topography, temperature and salinity anomaly fields are presented. Reasonable agreement is obtained between the model results on currents and the observational data. The computed anomaly fields for temperature and salinity at selected depths during Spring show that the observed temperature and salinity data were adapted with surface wind, flow field and bottom relief of the ocean and that the observed data were found to be fully smoothed during the adaptation stage. Copyright (C) 1999 John Wiley & Sons, Ltd.

Shakher, C; Nirala, AK, A review on refractive index and temperature profile measurements using laser-based interferometric techniques Source: OPTICS AND LASERS IN ENGINEERING, ELSEVIER SCI LTD, Vol.31.00 Issue. 6 pp.455-491 1999.

Abstract: In this review we have discussed laser-based interferometric techniques for measurement of refractive index, temperature and temperature profile of burners with special emphasis on laser speckle techniques and Talbot interferometric technique. (C) 1999 Elsevier Science Ltd. All rights reserved.

Shanker, R; Vrat, P, Some design issues in cellular manufacturing using the fuzzy programming approach Source: INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH, TAYLOR & FRANCIS LTD, Vol.37.00 Issue. 11 pp.2545-2563 1999.

Abstract: Fuzzy programming models are presented in this paper for the design of cellular manufacturing systems at the post-clustering stage. Various strategies to deal with exceptional elements and bottleneck machines have been considered. The models are designed to handle linguistic vagueness in the estimates of system parameters. A multi-objective formulation is also presented to handle informational vagueness. Two problems are selected from literature to illustrate the models. The multi-objective fuzzy model is compared with an equivalent goal-programming formulation. The results indicate that the strategy to deal with subcontracting of exceptional parts and duplication of bottleneck machines may be quite different as compared to deterministic models, if the vagueness in situational-parameters is captured. The models are effective in handling uncertainty in design parameters and are therefore expected to provide a more realistic CMS design.

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