1. Journal Articles

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Digital Simulation of Multimachine Power Systems for Stability Studies
(1968) Prabhashankar, K.; Janischewsyj, W.
A digital simulation technique suitable for detailed analysis of both large and small disturbances on extensive power systems is presented. The analysis employs a hybrid reference frame for statement of the problem and for its solution. The equations of the interconnecting network are expressed with regard to a synchronously rotating common reference frame and are treated with the aid of matrix methods. Synchronous machine equations and equations of the voltage regulator and of the speed governor are solved in Park's reference frame fixed to the field of each individual machine. Provision is made for representing different machines in different degrees of detail. An efficient numerical technique for solution of the resulting complex nonlinear equations describing the behavior of the complete power system is introduced. Copyright 1968 by The Institute of Electrical and Electronics Engineers, Inc.
Properties of laterite aggregate concrete
(1972) Raju, N.K.; Ramakrishnan, R.
The paper presents the results of tests conducted on fresh and hardened concrete using laterite as aggregate. Several mixes of laterite aggregate concrete were made with varying watercement and aggregate-cement ratios to study the properties like workability, compressive, flexural, tensile strength and Modulus of elasticity. The tests indicate that the workability decreases with increasing aggregate-water ratio. The compressive strength of laterite aggregate concrete is considerably lower than that of gravel or crushed granite aggregate concrete, while the average ratio of cylinder to cube strength compared favourably with that for normal aggregate concrete, for the range of aggregate and water-cement ratios covered in this investigation. 1972 Secr tariat de R daction.
An Experiment to Determine the Relative Permeability of Ferrites
(1972) Prasad, B.S.N.; Shastry, S.V.; Hebbar, K.M.
Relative permeability ?r of a ferrite rod can be determined by finding the series resonant frequencies of a simple L-C-R circuit with and without the rod inside the inductance coil. Compared to other methods employed for the determination of permeability, this method is simple and easy to perform in the laboratory. Using the value of ?r from this experiment, ?o the absolute permeability of free space has been determined which provides a check for the correctness of this experiment. 1972, American Association of Physics Teachers. All rights reserved.
Proton magnetic shielding anisotropy in acetylene
(1973) Mohanty, S.
A high resolution N.M.R. study of acetylene in different liquid crystals is reported. The anisotropy in proton chemical shift has been measured accurately. The present result differs considerably from the values previously reported and is found to be independent of liquid crystal medium, concentration or density and reference of chemical shift measurement. Additional chemical shift data in gaseous acetylene and methane tetramethylsilane (TMS) relative shifts in nematic and isotropic phases of the liquid crystals are also given. 1973 Taylor & Francis Group, LLC.
Nuclear magnetic resonance studies of 13 C-enriched acetylene
(1973) Mohanty, S.
Analysis of 1H and 13C spectra of 1-13 C-acetylene gives the same relative sign for JCH and J'CH. Precise chemical. 1973.
A new rotating-boat technique for liquid phase epitaxial growth of gallium arsenide
(1973) Ravi, H.N.; Guha, S.; Sarpangal, S.
A new technique has been developed to avoid constitutional supercooling in the growth of gallium arsenide by liquid phase epitaxy from an unconfined Ga-rich solution. This technique utilises a graphite boat that permits the growth solution to be initially saturated with GaAs at a temperature significantly higher than the substrate temperature. The boat is rotated to bring the solution into contact with the substrate, and rotated again to decant the solution after the growth is completed. If the initial temperature difference between the solution and the substrate is high enough, constitutional supercooling does not occur, and this procedure yields epitaxial layers with smooth surfaces free of cellular structure. 1973.
Flexural behaviour of pretensioned concrete beams with limited prestress
(1973) Krishna, Raju, N.; Basavarajaiah, B.S.; Ahamed, Kutty, U.C.
The behaviour of class-3 type prestressed concrete beams, at the limit states of cracking, deflexion and collapse are investigated by experiments on pretensioned beams with mild steel as supplementary reinforcement. Several methods of calculating the width of cracks are examined in the light of experimental results and an empirical formula, which includes the effect of percentage of untensioned reinforcement is suggested. The deflexions of beams, based on the method of Beeby and Taylor, were marginally conservative when compared with the experimental results. The ultimate moment capacity of concrete sections with tensioned and untensioned reinforcement, was underestimated by as much as 10, 15 and 25 per cent by the Indian, British and American Code recommendations. 1973.
Drop Nusselt numbers in dropwise condensation
(1974) Nijaguna, B.T.
Most of the theoretical studies in dropwise condensation have based their analysis on the principle that the heat transfer rate limiting mechanism in dropwise condensation is the conduction of heat through drops. Based on this principle, Fatica and Katz presented shape factor values for droplets and these values have been used by other studies. 1974 Martinus Nijhoff, The Hague.
Asymmetric response of circular plates
(1974) Ramakrishnan, R.; Kunukkasseril, V.X.
This paper deals with the response of thin elastic circular plates to asymmetric loadings. The normal mode method of analysis is used. The transient reponse to an impact force away from the centre and to a concentrated impulse moment at any point are investigated. A comparison of analytical results with those from experimental study of response to an impact force is included. It is considered that the method of analysis developed can be used to determine design stresses. 1974 Academic Press Inc.
Test performance of a ten tonnes reinforced concrete loading frame
(1974) Raju, H.K.; Basavarajaiah, B.S.
The paper reports an experimental investigation on a reinforced concrete loading frame of ten tonnes working load capacity. The loading frame was fabricated by using two doubly reinforced concrete beams to serve as flexural members. Eight numbers of mild steel rods connected to the beams by plates and nuts served as supports for the beams and also as tension members during testing of structural elements. The stress distribution and loadeflexion characteristics of the flexural members of the frame was investigated in the working load range of to tonnes. Theoretical and experimental observations indicated that the flexural member behaves like a beam with partial fixity at the ends. 1974 Secr tariat de R daction.
On exceptional values of entire and meromorphic functions
(1974) Narayanan, K.A.
Let f(z) be meromorphic function of finite nonzero order ?. Assuming certain growth estimates on f by comparing it with r?L(r) where L(r) is a slowly changing function we have obtained the bounds for the zeros of f(z) -g (z) where g (z) is a meromorphic function satisfying T (r, g)=o {T(r, f)} as r ? ?. These bounds are satisfied but for some exceptional functions. Examples are given to show that such exceptional functions exist. 1974 Indian Academy of Sciences.
Flow stress - grain size relationship in aluminum
(1975) Shiroor, V.S.; Kulkarni, A.G.; Prasad, Rao, P.; Parameswaran, V.R.
[No abstract available]
Flow of viscous stratified fluid of variable viscosity past a porous bed
(1976) Channabasappa, M.N.; Ranganna, G.
To study the effects of stratification and slip velocity on the flow of fluid of variable viscosity over a permeable bed, we divide the flow into two zones called zone 1 and zone 2. Zone 1 pertains to the flow called the free flow governed by the Navier-Stokes equations in the region between the impermeable upper plate and the porous bed.. Zone 2 pertains to the flow in the bed governed by the modified Darcy Law. Using the slip velocity boundary condition, velocity distributions in zones 1 and 2 are obtained and are matched at the interface. The boundary layer thickness just beneath the permeable interface and the friction factor are also obtained. 1976 Indian Academy of Sciences.
The effect of the thickness of the porous material on the parallel plate channel flow when the walls are provided with non-erodible porous lining
(1976) Channabasappa, M.N.; Umapathy, K.G.; Nayak, I.V.
Flow through a channel whose walls are lined with non-erodible porous material is investigated using Beavers and Joseph slip boundary condition. It is shown that the effect of porous lining is to increase the mass flow rate and to decrease the friction factor. 1976 Martinus Nijhoff Publishers.
Exhaust emission characteristics correlated to a chemically equilibrating gaseous system in an SI engine
(1976) Samaga, B.S.
The chemical reactions leading to the destruction of NO and CO in the engine combustion gases are temperature dependent and it has been observed that they change over from 'shifting' equilibrium to 'frozen' equilibrium as the temperature drops during the expansion phase. Application of reaction rate theories to the prediction of exhaust emissions is complex and can at best be an approximation owing to uncertainties of the engine combustion reaction mechanism, the assumed rate constants and the estimated combustion temperatures. An attempt was made to correlate the computed equilibrium concentrations during the expansion phase to the measured emission levels of NO and CO to estimate the temperatures at which nonequilibrium effects become apparent. Comparison of the measured emission levels from a single cylinder spark ignition engine with the computed equilibrium concentrations for several engine operating conditions has shown that the concentration of NO freezes near its peak equilibrium value, whereas the destruction of CO continues during the subsequent expansion phase until the temperature has dropped to an effective 'frozen equilibrium temperature' at which the computed equilibrium CO corresponds to the measured level in the exhaust. This temperature is dependent on the time rate of expansion and was determined to be 1250 K at 600 rpm and 1300 K at 900 rpm for the steady state operating conditions considered in the present series of tests.An attempt has been made to correlate the computed equilibrium concentrations during the expansion phase to the measured emission levels of NO and CO to estimate the temperatures at which nonequilibrium effects become apparent. Comparison of the measured emission levels from a single cylinder spark ignition engine with the computed equilibrium concentrations for several engine operating conditions has shown that the concentration of NO freezes near its peak equilibrium value, whereas the destruction of CO continues during the subsequent expansion phase until the temperature has fallen down to an effective 'frozen-equilibrium temperature' at which the computed equilibrium CO corresponds to the measured level in the exhaust.
Free vibration of stiffened circular bridge decks
(1976) Ramakrishnan, R.; Kunukkasseril, V.X.
An analytical method for determining the free vibration frequencies of stiffened curved bridge decks is presented. The bridge deck is idealized as a system consisting of a number of concentric annular plate and circular ring segments rigidly connected to each other. From the closed form solutions for free vibration of the individual plate segments and rings, the frequency of the system is obtained by imposing the edge and continuity conditions. Results for several cases are furnished and a comparison with experimental results is also presented. 1976.
Response of circular bridge decks to moving vehicles
(1977) Ramakrishnan, R.; Kunukkasseril, V.X.
This paper discusses the dynamic response of a curved bridge deck to a moving vehicle. The bridge deck is idealized as a set of annular sector plates and circular rings rigidly jointed together. On the basis of classical plate and ring theories a method has been developed to obtain the response to a moving vehicle idealized as a spring mass system. After obtaining the normal modes and frequencies and establishing the orthogonality conditions, the problem of the forced motion of the deck is solved by the method of spectral representation. Numerical results have been presented to illustrate the effect of several vehicle and bridge parameters on the response. Copyright 1977 John Wiley & Sons, Ltd
Pre combustion energy release and its effect on flame propagation and exhaust emissions in a spark ignition engine
(1977) Samaga, B.S.; Murthy, B.S.
The extents of pre combustion reaction and cumulative pre combustion energy release have been computed for various operating conditions in a single cylinder variable compression ratio research engine. Exhaust emission levels of CO and HC are measured by gas chromatography. The mean turbulent flame propagation velocity is estimated from a thermodynamic analysis of the engine cylinder pressure trace. The effect of pre combustion energy release on the flame velocity and the exhaust emissions of CO and HC has been discussed. It is found that the pre combustion energy release may account for as much as 20% of the heat in the fuel in the case of reactive fuels of relatively low octane numbers. In general, increased pre combustion reactivity is found to decrease CO and HC emission levels. However, its effect on the mean engine flame velocity does not appear to be pronounced.The extents of pre-combustion reaction and cumulative pre-combustion energy release have been computed for various operating conditions in a single cylinder variable compression ratio research engine. Exhaust emission levels of CO and HC are measured by gas chromatography. The mean turbulent flame propagation velocity is estimated from a thermodynamic analysis of the engine cylinder pressure trace. The effect of pre-combustion energy release on the flame velocity and the exhaust emissions of CO and HC has been discussed. It is found that the pre-combustion energy release may account for as much as 20% of the heat in the fuel in the case of reactive fuels of relatively low octane numbers. In general, increased pre-combustion reactivity is found to decrease CO and HC emission levels. However, its effect on the mean engine flame velocity does not appear to be pronounced.
Vapor phase oxidation of p?xylene
(1978) Mathur, B.C.; Viswanath, D.S.
The kinetics of the vapor phase oxidation of p?xylene over ferric molybdate catalyst were studied in an isothermal, differential, tubular flow reactor in the temperature range of 360 to 420� C. The major product obtained was p?tolualdehyde with small amounts of maleic anhydride and p?toluic acid. No terephthalic acid or CO2 were observed. The reaction rate data collected fit the redox model given by Equation 1. The values of activation energies Ex, Eo and frequency factors Ax, Ao obtained are 72, 63 kJ/mol and 0.64, 2.89 m3/kg catalyst s respectively. The reaction mechanism was established by studying the oxidation of p?tolualdehyde, toluic and terephthalic acids. It is concluded that the reaction follows a parallel?consecutive scheme. Copyright � 1978 Canadian Society for Chemical Engineering
4-Amino-3-methyl-5-mercapto-1,2,4-triazole as a gravimetric reagent for determination of silver in silver compounds, alloys and complexes
(1978) Gadag, R.V.; Gajendragad, M.R.
A simple, convenient and accurate gravimetric method for the determination of silver is presented. 4-Amino-3-methyl-5-mercapto-1,2,4-triazole precipitates silver quantitatively from ammoniacal tartrate medium. The complex is weighed as AgC3H5N4S after drying at 120-30 . Separation of silver from a large number of cations is described. Application of the method for quantitative analysis of alloys and complexes of silver is reported. The average relative error for the range 20-70 mg of silver is 0.25% and the relative standard deviation at the 40-mg level is 0.2%. 1978.