Showing papers by "Indian Institute of Technology Kharagpur published in 1972"

Effect of homogeneous and heterogeneous reactions on the dispersion of a solute in the laminar flow between two plates

Abstract: The paper presents an analytical solution for the dispersion of a solute in a liquid flowing between two parallel plates in the presence of an irreversible first-order chemical reaction. The effects of both homogeneous and heterogeneous reactions on the dispersion are studied under isothermal conditions. It is found that for homogeneous reaction in the bulk of the liquid, the effective Taylor diffusion coefficient decreases with increase in the reaction rate constant. Further for heterogeneous reaction at the catalytic walls, Taylor diffusion coefficient is also found to decrease with increase in the wall catalytic parameter for fixed reaction rate constant corresponding to the bulk reaction.

Bearing capacity theory from experimental results

Abstract: The development of a theory of bearing capacity of strip footings on cohesionless soils, based on a failure surface deduced from the experimentally observed surfaces, is reported in this article. The deduced surface is different from the failure surfaces assumed in the commonly used theories. In the high ranges of the angle of internal friction of soil the deduced surface is much smaller than those assumed in theories. When the plane-strain value of the friction angle of soil is used, the developed theory gives a very accurate prediction of the bearing capacity while the existing theories fail to do so.

Momentum transfer in a horizontal liquid‐jet ejector

Abstract: The performance of a horizontal liquid-air ejector system was greatly enhanced by creating mixing shock. Principles of macroscopic momentum and energy balances were employed to define an overall loss factor which was found to be a useful correlating parameter in the case of homogeneous bubble flow. Empirical correlations are proposed to predict mass ratio as a function of different parameters.

Beach structures produced by crab pellets

Abstract: It has been observed that seashore crabs produce various designs by the ejected faecal pellets. Study of such structures shows a clear association of them with different parts of the beach. Mossy structures are found only in the upper beach part, i.e., along the high-water line, whereas concentric-radiating and asteroid types are encountered in the middle beach area. In regions above mean high-tide line burrow openings are surrounded by loose sediments and are devoid of any patterns. In the lower beach zone such structures are lacking. If the beach materials are more silty in character, faecal pellets congregate and stand out as knobby surfaces. Closer examination of such structures, if preserved in ancient sediments, may not only help in delineating the ancient shoreline positions but also may help in demarcating littoral micro-environments.

Brink Depth for Trapezoidal Broad-Crested Weir

Abstract: Brink depth characteristics include the relationship between brink depth (y\do) and critical depth for parallel flow (y\dc); variation of Froude number at the brink with the ratio y\do/y\dc, and variation of pressure coefficient (k\d1). More than 400 tests performed on lucite models of broad-crested weir of trapezoidal cross section with, 1:1 side slope, width varying from 8.5625 ft to 20.1333 ft, slope of crest varying from level to steep, and entrances both square cornered and rounded, reveal the value of y\do/y\dc ranged from 0.700 to 0.757. The value of y\do/y\dc is constant for a particular weir model irrespective of discharge, but is generally different for different weir models, varying with the slope and breadth of the weir crest, and the entrance condition; the Froude nubmer at the brink is a function of only (y\do/y\c); K\d1 and thus the total residual pressure at the brink section depends on the Froude nubmer and is, generally, not zero.

Structural evolution of the Simla klippe in the lower Himalayas

Abstract: The rocks of the Jutogh Series in the Simla area have been involved in folding of three generations and metamorphism in two phases The earliest structures are isoclinal, recumbent/reclined folds (F1) with a shallow plunge toward east or west where least reoriented The axial surfaces of these folds have been folded coaxially into open, upright antiforms and synforms (F2), which become tight to isoclinal in the northern part, causing local involution The F1 and F2 folds have been affected by conjugate and chevron folding (F3) with an overall NS strike of axial planes, resulting in axial culminations and depressions of the early folds Axial plane foliation related to F1 folding and transposition schistosities parallel to the axial planes of the F2 and F3 folds are the planar deformation structures that have developed Cross stratification at one contact of two rock-units suggests that the structure of the Jutogh Series in the largest scale is a recumbent syncline, the peaks of Taradevi, Jutogh and Prospect Hill representing the inverted limb The Jutogh rocks are surrounded and structurally underlain by the rocks of the Chail Series The open, synformal nature of the Jutogh-Chail boundary in contrast with the complex fold-geometry within the Jutogh Series, tearing-off of the largescale early folds and sharp break in the first metamorphism at the Jutogh-Chail contact, and widespread cataclasis all along the border prove that the Jutogh Series has been thrust over the Chail Series forming a klippe in the Simla area Continuation of the second metamorphism and the third folding across the Jutogh thrust indicates that the thrusting preceded F3 and was broadly coeval with the F2 movement An unrestricted southward transport could generate the F1 recumbent folds The F2 folds point to a flattening in the waning phase of the overthrust movement in broadly the same plan of deformation The F3 folds indicate a compression in an EW direction in the last phase of deformation

Mechanism of elutriation from fluidised beds

Abstract: Elutriation can be used as a convenient method for classification of particles. However, it has been observed that complete elutriation is not possible. Elutriation stops when the concentration of the elutriating component in the bed reaches an equilibrium value. The rate equation for elutriation has been found to be analogous to that of a first order reversible chemical reaction. In this paper two correlations—one for evaluating the equilibrium bed concentration and the other for the elutriation rate constant have been proposed by relating these quantities with the relevant system parameters. On peut employer l'elutriation d'une maniere satisfaisante pour le classement des particules. On a, toutefois, note qu'il est impossible de realiser une elutriation complete: elle s'arrete lorsque la concentration du produit qui subit l'elutriation dans le lit atteint une certaine valeur d'equilibre. On a trouve que l'equation de la vitesse d'elutriation etait analogue a celle d'une reaction chimique reversible et de premier ordre. On propose dans le present travail deux correlations: une pour evaluer la concentration d'equilibre du lit et l'autre pour determiner la constante de vitesse d'elutriation; on a, a cette fin, etabli une relation entre les valeurs en question et les parametres pertinents du systeme.

Non-Existence of axially symmetric massive scalar fields

Abstract: It has been observed that for the axially symmetric Einstein-Rosen metric, the stress-tensor of a scalar meson field associated with meson of rest mass μ cannot be the source term for generating gravitation. The above result also holds even when this meson field is coupled with an electromagnetic field.

Decay of vortices in a visco-elastic liquid

Abstract: Decay of vortices in the flow of a certain class of visco-elastic liquids (incompressible second-order fluids) is investigated. It is found that in the flow of double array of vortices, the vortices decay much faster in such a liquid than in ordinary viscous liquids. For the flow in the wake of such a liquid past a two-dimensional grid, a pair of bound eddies occur behind the single elements of the grid as in the viscous case but their scale diminishes with increase in the elastic parameter.

The shapes of the LIII X-ray absorption discontinuity of rhenium in compounds

Abstract: The X-ray LIII absorption edge of rhenium in the pure metal and in two compounds, namely, K2ReCl6 and KReO4 has been studied using a Cauchois type bent crystal spectrograph of 40 cm diameter. The splitting of the main absorption discontinuity has been observed for the first time in the compounds. This splitting and the edge structure of the Re LIII discontinuity in the compounds have been interpreted on the basis of molecular orbital diagrams. The crystal field splitting, Δ, has been determined experimentally in both the compounds in the solid state.

The effects of magnetic field oscillations on the boundary layer flow past a magnetized plate

Abstract: The effects of harmonic oscillations of amplitude e in the magnitude of the magnetic field on the steady boundary layer flowO(ɛ2) due to a uniform free stream past a semi-infinite magnetized flat plate have been discussed. It is observed that the magnetic field distribution does not affect the surface current distribution.