Showing papers by "Birla Institute of Technology and Science published in 1978"

A physical model for the stress-induced electromagnetic effect in metals

Abstract: Observations of the fracture-induced electromagnetic effect in metals have recently been reported by the author. This paper presents a physical model for explaining this new effect. The reasoning attributes the observed electromagnetic effect to dislocationelectron interactions in a metal. The frequency of the emitted radiation has been calculated from Bohr's correspondence principle and potential on the basis of Hertzian dipole radiation. The proposed physical model predicts emission of electromagnetic waves at distinct transition stages of elastic-plastic deformations. The paper also presents some of the experimental results, being obtained by the author, which confirm the practicability of this approach.

On a class of nonlinear integral equations

Abstract: In this paper we consider abstract equations of the typeK ν ν +ν =w 0, in a closed convex subset of a separable Hilbert spaceH. For eachv in the closed convex subset,K v :H →H is a bounded linear map. As an application of our abstract result we obtain an existence result for nonlinear integral equations of the typeν(s)+ν(s)∫ 0 1 k(s,t)ν(t)dt =W 0(s) in the spaceL 2 [0,1].

Inclusive quasielastic deuteron production

Abstract: It is argued that the measurement of the inclusive quasielastic deuteron production cross section coming from intermediate energy nucleus bombarding nuclei is of considerable theoretical interest. The inclusivity of the measurement leads to simplifications and allows a quasiclassical description to be used. A simple, heuristic, and quantum mechanically well defined formula is derived which includes for the first time a realistic treatment of the multiple scattering complications inherent in the problem. A rough calculation based on this formula gives reasonable agreement with the limited data available. We conclude that the observed number of deuterons does not require nuclear clustering and that the reaction is not highly peripheral. We believe that this and related reactions offer a greater possibility of yielding information on nuclear correlation than had been supposed. The theory of this reaction is shown to be fundamentally related to recent quasiclassical theories of heavy ion collisions.

A simple solar tracking system

Abstract: A falling weight controlled by a pendulum drives a shaft which is parallel to the axis of the earth at a rate of one revolution per day. The concentrator (convex lens) is mounted on the shaft and it thereby tracks the sun. Changes in the declination of the sun are accounted for correctly when the device is adjusted manually to point towards the sun each morning. A method is presented for correctly aligning the rotating shaft parallel to the axis of the earth by making observations of the focal spot of the sun.

Influence of Rear Body Eccentricity on Supersonic Base Pressure

Abstract: Base pressure measurements for a blunt cone in the presence of a following body of different eccentricities are presented. The measurements were carried out for sting-supported models on a blowdown-type Mach 2 wind tunnel. The results were obtained for a range of Reynold's number in which its influence was suspected to be appreciable, on the basis of earlier investigations by other authors. The variation of Reynold's number was obtained by changing the stagnation pressure of the tunnel. The influence of following bodies on the base pressure was found to be appreciable, whereas the dependence of the base pressure on the Reynold's number in the range of investigation was not found to be marked. Also, it was found that the asymmetric body affected the symmetry of base pressure, setting a cross force on the blunt cone under test. The study could be of relevance to the prediction of base pressure of multistage rockets in flight when the lower stage after separation is in proximity to the upper stages. Nomenclature d • = diameter of rear body D = diameter of base of blunt cone x = axial distance of the front face of the rear body from the base e = eccentricity (i.e., distance between axes of the test body and the rear body), mm PB = base pressure Pco =freestream static pressure NRg = Reynold's number based on base diameter NRL = Reynold's number based on body length

Bits solar water pump & related systems

Abstract: A programme of development of a water pumping system without any moving parts using solar energy and related systems has been underway since 1975. The pumping system designed is a passive system and operates on the ability of organic liquid (pentane/petroleum ether) vapours generated by solar heating in flat plate collectors, for pushing water directly, contained in a closed tank to an overhead tank or for any other use. The vapour in water tank is condensed causing a partial vacuum and water from inlet is sucked into the tank in order for the cycle to begin again. This paper describes studies conducted on 130, 2600, 12000 litre capacity water tank solar pumping systems. The operation of pump critically depends on correct manipulation of valves and also on monitoring the rise and fall of water levels in the water tank. The discharge head practically has no theoretical limit. However the suction head has basic physical limitation. The feasibility of such a pump can be only visualised in terms of regions where conventional energy sources are either not available or available on a restricted basis.

A strategy for the development of some low grade thermal devices

Abstract: Feasibility reports of many low grade thermal devices have been received over the last few years. NOST expert panel on Solar Energy expressed optimism in its report (1) about the early commercialization of some of these devices, prominent amongst these being solar water heaters and solar still. Similar conclusions have been drawn by the National Academy of Sciences (2). Judging from the long list of published papers in various journals over the last ten years, there has been a very significant rise in the number of researchers involved in the study and design of these low grade thermal devices. There is no reason to doubt that most of the devices work as claimed. However, corresponding absorption of the devices in our cultural and productive life has not taken place in India. This paper addresses itself to this dichotomy and analyses the various underlying reasons that have restricted the large scale adoption of these devices and while giving suitable recommendations for an R & D plan, also reports the results of various efforts in these directions.

Thermo-osmosis of water through composite clay membranes— The parallel arrangement

Abstract: Thermo-osmosis of water through a composite clay membrane consisting of kaolinite and crysotile clay membrane elements in a parallel array has been studied Water flux in presence of both pressure difference and temperature difference for the parallel composite clay membrane and also for the constituent clay membrane elements has been shown to be adequately described by the usual linear and homogeneous phenomenological equation The combination rules for the phenomenological coefficientsL 11 andL 12, representing hydraulic permeability and thermo-osmotic permeability, as deduced from the theory of Kedem and Katchalsky, have been found to be valid The validity of the combination rules forL 11 andL 12, in the case of parallel composite membrane has yielded a relationship between the heat of transport of water for the parallel composite membrane and the heat of transport of water for the constituent clay membrane elements

Development of solar still for the supply of laboratory distilled water and potable water for a typical village home

Abstract: The chief R & D task on solar stills, like other devices, is to adopt a design for a specific need of a typical consumer. So, two prototypes have been considered one for the laboratories at BITS and a typical village family for drinking purposes and another one for a village physician (Vaid) for making prescriptions. In this study are presented the experimental and theoretical results and fuel saving analysis of these designs. The results so far are quite encouraging.

Solar energy conversion through phase transformations

Abstract: Sodium thiosulphate pentahydrate and sodium sulphate decahydrate show appreciable potential differences and currents when the solid phase is in contact with its molten phase. the studies offer a new method for converting solar energy into electrical power.

A report on the various heat collection and heat storage systems evolved under the solar energy programme at b. i. t. s.

Abstract: This paper is a report on the various heat collection and heat storage systems evolved at BITS The paper reports the performance of flatplate collectors heating a low boiling organic liquid as an adjunct to BITS Solar Pump Also given in the paper is an economic alternative to a conventional solar water heater Further, methods for space heating and cooling are discussed Possibility of combining a collector and concentrator to achieve higher temperatures and to be able to raise-steam is also investigated

Generalized Measures for Large Deformations

Abstract: In engineering materials, even in the largest purely elastic deformations, the strain is small even though the displacement gradients and rotations may be large. In such cases there is very little gained in altering classical linear strain-stress tensor constitutive equations. In 1935, a paper by B.R. Sethi renewed interest in such problems, and then followed a host of papers by prominent workers in the field of continuum mechanics. A number of them wanted to consider incompressible materials like rubber and produced complicated constitutive equations, for which many adhoc approximations had to be made to get an agreement with experimental results. But with the advent of soft alloys and high polymers the problem of large deformations, involving severe strains, has again put the constitutive equations in the melting pot. Even though all branches of science have adopted Generalized Measures for problems both at the micro and macro levels, the engineer has been reluctant to change his concepts. He does not want to go beyond the Cauchy and Hencky measures. It should also be appreciated that high speed computation of engineering problems can give reliable results only if the order of strain measure is prescribed in advance. Thus arises the need of adopting generalized measures to simplify constitutive equations and to get better agreement with experimental results.

Radiation from a radial waveguide in a magnetoplasma

Abstract: The radiation patterns of an open-ended radial waveguide in a magnetoplasma have been obtained at high frequencies under the quasi-longitudinal (q.l.) approximation. It is shown that a radial waveguide can be conveniently used as a spacecraft antenna.