2. Conference Papers

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On the problem of predicting burning rates in a spark ignition engine
(1975) Samaga, B.S.; Murthy, B.S.
In this paper, formulation of a mathematical model for flame propagation in a spark ignited reciprocating engine has been described. As against the common practice of assuming a laminar flame propagation model with a suitable multiplying factor for turbulence effects, a more logical approach has been adopted bringing in the concept of an engine Reynolds parameter as the criterion to determine the combustion acceleration due to turbulence. The laminar burning velocity is calculated from Semenov's thermal model for the instantaneous unburned gas condition during combustion and is augmented for engine gas turbulence through an empirical function of the engine Reynolds parameter assuming wrinkled flame model. The turbulent flame velocity thus obtained is then corrected for flame transportation due to the expansion of the burning gases. The empirical constants in the formula have been evaluated in correlation to results of extensive experimentation on a single cylinder variable compression ratio research engine.
Investigation of a turbulent flame propagation model for application for combustion prediction in the S.I. engine
(1976) Samaga, B.S.; Murthy, B.S.
This paper is a follow-up of the authors' earlier paper(1)* in which the development and evaluation of a mathematical model for turbulent flame propagation in the S.I. Engine had been described. The present paper gives a report of further studies regarding the general applicability of this model for S.I. engine combustion prediction. A simplified scheme has also been suggested to predict the pollutant emission by a correlation of the computed equilibrium mole fractions to the measured emission levels of 'CO' and 'NOx' in the exhaust. A wide variety of operating conditions has been considered and the model is applied in a simulation program to compute the combustion and exhaust emission characteristics for each operating condition. The predicted results, in general, are in conformity with the experimentally measured results reported in literature. Copyright � 1976 Society of Automotive Engineers, Inc. All rights reserved.
CONVECTIVE HEAT TRANSFER BY AXIAL FLOW IN AN ANNULUS WITH POROUS LINING.
(1983) Channabasappa, M.N.; Umapathy, K.G.; Nayak, I.V.
This paper covers a theoretical model of convective heat transfer by axial flow in an annulus bounded by two long concentric circular cylinders, the outer surface of the inner cylinder being provided with a non-erodible porous lining and the two bounding surfaces being maintained at constant temperatures. The analysis makes use of the velocity slip and the temperature slip boundary conditions at the interface and employs Brinkman model to obtain the velocity field in the porous zone. The influence of various parameters on the velocity and temperature fields is studied.
SOLAR INSOLATION AT SURATHKAL - WEST COAST OF INDIA.
(1986) Nijaguna, B.T.
In an attempt to obtain the applicable correlation for the estimation of solar intensity at Surathkal, the number of bright sunshine hours and actual solar insolation were monitored. Regression analysis of the measured data when fitted by a least squares technique resulted in constants in an Armstrong-Page type correlation on a monthly, seasonal and annual basis. The obtained correlations are least erroneous when compared with the actual measured data and are also more appropriate compared to estimates obtained from formulae reported by other studies.
STUDIES ON SUBSURFACE WATER POTENTIAL AND QUALITY FOR IRRIGATION.
(1987) Ranganna, G.; Gajendragad, M.R.; Naganna, C.; Gurappa, K.M.; Nayak, I.V.; Chandrakantha, G.; Rao, P.R.M.
The region of Western Ghats comprising the Sahyadri Mountain chain in southern India has remained underdeveloped notwithstanding its rich natural resources and flora and fauna. The Aladangadi Hole (river) basin is one such area. Although the basin receives very heavy rainfall, it faces water scarcity problems and thus has remained undeveloped. Intense development in the coastal region has created increasing demands for fresh water. As a pilot study, hydrological investigations for the yield, quality of water and soil, aquifer parameters, soil-water-crop compatibility, groundwater potential and Landsat imagery studies have been undertaken. This paper highlights several aspects of irrigation for an all-round development of the basin.
ELECTRO-CHEMICAL BEHAVIOUR OF COATED REINFORCEMENT IN CEMENT CONCRETE.
(1987) Patil, B.T.; Gajendragad, M.R.; Ramchandran, T.; Ranganna, G.; Sudhaker, Nayak, H.V.
Concrete constructions exposed to marine environments eventually suffer from corrosion of embedded steel rods, in its advanced state, this corrosion can crack the concrete and weaken the structure. The behaviour of paint coated reinforcements in cement concrete containing different amounts of chloride through an electrode polarization technique. Coated steel rods perform better as far as corrosion of rebar is concerned.
Interactions of a group of vertical cylinders in water waves
(1989) Reddy, K.I.S.; Kumar, B.N.; Dattatri, J.
An analytical procedure involving Bessel functions is applied to investigate the wave interactions with a group of vertical circular cylinders. Considering the scattered wave at each cylinder in terms of Hankel functions, the inter-scattering of the waves from other cylinders is considered in the investigations. Wave forces and hydrodynamic coefficients in terms of the diffraction characteristics of single cylinders are evaluated for various groups of cylinders. A two cylinder group is considered for experimental verification of the theory. A comparison of the present procedure with boundary element and finite element methods is made.
Data/voicenideo integration on fiber distributed data interface
(1990) Rudramuni, B.; Hegde, G.D.; Muthangi, S.P.; Paulraj, A.
The Fiber Distributed Data Interface (FDDI) is a 100 megabit per second (Mbps) Local Area Network that uses Optical Fiber as the medium. It provides both the high bandwidth and low latency needed to match the capacity of future personal computers. Hence it is expected to become the preferred local area network systems of the 1990s. The FDDI protocol is based on a timed token ring access method. In this paper, we propose a media access control protocol for combined Data/Voice/Video services on FDDI. The most important service requirement for the packetized Voice and Video is the transport of this data with tolerable delays. Ile effect of multiple Voice and Video channels on the asynchronous data traffic and the capacity to handle these services on FDDI is investigated by means of simulation methods. � 1990 IEEE.
Performance of plasticized/superplasticized concrete in the marine environment
(1994) Patil, B.T.; Gajendragad, M.R.; Ranganna, G.; Wagh, A.B.; Sudhakaran, T.
The use of admixtures, particularly plasticizers and superplasticizers in concrete, is gaining much attention now a days. Their use increases the workability of concrete which allows reduction in W/C ratio, resulting in reduced permeability. The major factor affecting durability of RCC in an aggressive environment like marine is the corrosion of reinforcement due to the corrosion inducing substances present in the media, which reaches its surface by ingression through concrete. Hence one can expect that the use of these admixtures can improve the performance of RCC in the marine environment provided proper W/C ratio is used. In the present study, the performance of RCC containing three indigenous admixtures namely, a plasticizer and two superplasticizers at different dosages with reduced W/C ratio was studied. The study was carried out by assessing the corrosion of reinforcement in concrete electrodes containing these admixtures by means of potentiostatic polarization technique. The results show that the corrosion resistance of reinforcement in increased by the use of admixtures.
Minimizing power consumption in multiple fan networks by optimum fan selection
(1995) Kumar, G.Vijaya; Sastry, V.R.; Krishna, Rao, G.V.
One of the main objectives while planning ventilation systems for mines with multiple fans is minimization of the total airpower consumption of the mine. Solution of this problem by conventional ventilation network analysis programs is tedious and time consuming, and may not yield optimum results in all the cases. The paper presents an algorithm for solving multiple fan networks by finding optimum combination of fan operating points for required airflow distribution in the ventilation system.
Areal evapotranspiration estimation using several alternative formulations of the CRAE hypothesis
(1997) Nandagiri, Lakshman
Accurate estimation of ET from large irrigated areas is essential for sustainable development of land and water resources. The CRAE hypothesis offers a convenient technique for areal ET estimation using only regularly recorded meteorological data. In this study several alternative models for areal ET are derived from the fundamental CRAE hypothesis and their performances assessed using data of the Everglades Agricultural Area, Florida. Results indicate the feasibility of obtaining acceptable estimates of areal ET from irrigated land using the CRAE concept.
Pipelined Parallel Processor to implement MD4 Message digest algorithm on Xilinx FPGA
(1998) David S.
The paper presents a pipelined parallel processor architecture design to implement the MD4 message digest algorithm which computes the message digest or the fingerprint of 128 bit fixed length, for any arbitrary length of input message. The processor implements the arithmetic, logic and circular shift operations by a pipelined parallel process. The architecture is designed to suit the design flexibility of the Xilinx Field Programmable Gate Arrays (FPGAs) The processor reads the message from an external RAM, 16-bit at a time and internal operations are performed with 32-bit data. The major advantage of the design is increased speed of computation and minimum hardware. The processor computes the digest with a speed approximately three times faster than the software version implemented in DSP processors.
The independent components of characters are 'strokes'
(1999) Srinivasan, S.H.; Ramakrishnan, K.R.; Bhagavathy, S.
What are the natural features of handwritten characters and how to arrive at them automatically? We apply independent components analysis on handwritten characters. Independent components analysis extracts the underlying statistically independent signals from a mixture of them. We expect strokes to be the independent components of handwritten characters. Our findings show that stroke-like features emerge as a result of the analysis confirming the above intuition. This finding is significant since it gives automatic procedures for extracting stroke-like features from multilingual character data sets. We use these features for handwritten digit recognition using a very simple classifier. The classifier is chosen to be simple so that the quality of the input feature set can be evaluated. The recognition results indicate that the features arrived at by independent component analysis are useful. � 1999 IEEE.
Metal-mould interfacial heat transfer during solidification of cast iron against cast iron chills
(2000) Prabhu, K.N.; Griffiths, W.D.
Heat transfer during the unidirectional solidification of a cast iron alloy against cast iron chills was investigated using an inverse modelling approach. Chills of thickness 100 mm and 10 mm were used, to simulate gravity die casting conditions and the use of chills in sand moulds. In both cases transient heat transfer, measured by the interfacial heat flux and heat transfer coefficient, declined from initially high values in the first few seconds of solidification, to values about an order of magnitude lower which persisted for the remainder of the experiments. In the case of the thin chill it became saturated with heat until it was no longer in a position to extract further heat from the casting. These results were interpreted by studying the resistance to heat transfer from the casting offered by the casting-chill interface and the chill itself. For example, the thermal resistance of the casting-chill interface can be influenced by the deformation of their respective surfaces and their subsequent relationship.
Elimination of ground vibrations and fly rock: A case study of an opencast mine
(2001) Sastry, V.R.
At the JK Opencast Project, studies were made to eliminate the problems of ground vibrations and fly rock. Ground vibrations were studied with blast vibration monitors. Changes in the initiation pattern from earlier V-pattern to the straight-line pattern and reduction in charge weight per delay, resulted in elimination of ground vibrations problem. Adoption of straightrow pattern of initiation with a clear free face, introduction of air deck, bottom initiation of blastholes and muffling of individual holes with wire meshes overlain by sand bags of 25 kg resulted in complete elimination of fly rock.
Development of a link layer protocol using UML
(2001) Sekaran, K.C.
This paper presents a report on the development of a link layer protocol using an object oriented formal method. It describes the steps involved in the conceptualization, analysis and design of the L2CAP (Logical Link Control and Adaptation Layer Protocol) of the Bluetooth architecture. UML (Unified Modeling Language) is the formal modeling language used in this work. It has been shown how the static, dynamic and operational aspects of the system are captured using various UML diagrams. � 2001 IEEE.
Inverse modeling of heat transfer with application to solidification and quenching
(2002) Prabhu, K.N.; Ashish, A.A.
The inverse modeling of heat transfer involves the estimation of boundary conditions from the knowledge of thermal history inside a heat conducting body. Inverse analysis is extremely useful in modeling of contact heat transfer at interfaces of engineering surface during materials processing. In the present work, the one-dimensional transient heat conduction equation was inversely modeled in both cartesian as well as cylindrical coordinates. The model is capable of estimating heat flux transients, chill surface temperature, and total heat flow from the source to the sink for an input of thermal history inside the sink. The methodology was adopted to solve boundary heat transfer problems inversely during solidification and quenching. The response of the inverse solution to measured sensor data was studied by carrying out numerical experiments involving the use of varying grid size and time steps, future temperatures, and regularization techniques.
Computation of lightning induced voltages on telecommunication subscriber lines
(2002) Kannu, P.D.; Thomas, M.J.
The electric and magnetic fields produced by a lightning stroke in the vicinity of a telecommunication line can illuminate the line and it can acquire induced overvoltages which may be detrimental to the equipments connected to the telecommunication line. The magnitude and waveshape of the electromagnetic fields produced by lightning as well as the induced voltage on telecommunication line are influenced by the finite conductivity of the ground. In this paper, the induced transient voltages on an overhead telecommunication subscriber line due to a nearby lightning stroke to the ground are computed. From the results it is seen that the induced voltage is bipolar for all the observation points except at the line midpoint for the lightning striking point location chosen in this study. It is also observed that the finite ground conductivity decreases the magnitude of the induced voltage at the line terminations where as it increases the induced voltage as the line mid point is approached. The results obtained in this study will be useful in evolving a suitable lightning protection scheme for the rural telephone exchanges which are interconnected using overhead lines instead of underground cables as in the case of urban exchanges. At the same time these rural telephone exchanges have become more vulnerable to transient overvoltages as they are being converted into digital ones with their susceptibility levels for transient overvoltages being much lower than the old electromechanical exchanges. � 2001 Convenor.
One-dimensional predictive model for estimation of interfacial heat transfer coefficient during solidification of cast iron in sand mould
(2002) Narayan, Prabhu, K.; Griffiths, W.D.
A one-dimensional predictive model is proposed to estimate the interfacial heat transfer coefficients during unidirectional solidification of a cast iron alloy, vertically upwards, against a sand block. The model is based on the surface roughness characteristics of the casting and sand surfaces and the concave deformation of the initial solidified casting skin towards the sand surface. The modelled interfacial heat transfer coefficients and predicted temperatures inside the casting and the sand block showed an approximate agreement with experimentally determined values. The model showed that radiation was a significant mode of casting/sand interfacial heat transfer with the predicted contribution of radiation to the overall heat transfer being nearly 50%. The evaluation of the model in comparison to the interfacial heat transfer models proposed by Zeng and Pehlke suggested that the interfacial conditions considered in this model, namely, the mean peak to valley heights of the casting/sand mould surfaces and the gap width calculated from the deformation of the initial solid skin, gave a more accurate prediction. This predictive heat transfer model has an advantage over the inverse modelling technique as the matching of experimentally measured temperatures to determine the boundary conditions is avoided and the heat transfer coefficients can be estimated as an integral part of the casting simulation.
Computation of radiated electromagnetic fields from a lightning return stroke
(2003) Kannu, P.D.; Thomas, M.J.
This paper presents the computed electric fields produced by a lightning return stroke. It is observed that the rate of rise of lightning current does not influence the vertical component of electric field. The negative pre-pulse magnitude of the horizontal electric field increases with time derivative of the lightning current where as the initial negative peak of the horizontal electric field increases in direct proportion to the return stroke velocity. � 2003 Society of EMC Engineers.