Flows in a rotating elastico-viscous fluid induced by torsional oscillations of a plate acting for a finite time

Unsteady flows in an electrically conducting rotating elastico-viscous liquid in the presence of a uniform magnetic field and induced by small amplitude torsional oscillations, acting for a finite time, of an infinite, rigid, non-conducting plate, are discussed. This analysis indicates the general features of the steady and unsteady velocity field, and the structure of the associated boundary layers on the plate including the effect of rotation, hydromagnetic and elastic parameters involved in the problem. The velocity field related to small elastic parameter is calculated with physical significance. It is further shown that the Ekman suction velocity, which is responsible for the generation of an axial inflow toward the bounadry layer, does not appear unless the plate is subject to oscillations for an indefinite period. Several limiting results are found to follow as special cases of this analysis.     

Liesegang rings — Part I

Summary The conditions for the formation of revert type ofLiesegang rings have been studied here. Various systems of rhythmic precipitations of silver chromate are produced in a mixtures of agar and gelatin gels under different environmental conditions. Ring systems of silver, copper and other ferricyanides have also been studied in gelatin gel. The observations show that the cause of the revert systems ofLiesegang rings is the high peptizability of the precipitating matter in the media containing gel and the unreacted ions.

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Zusammenfassung Die Bedingungen der Bildung des „umgekehrten“ Types vonLiesegang-Ringen wurden untersucht. Verschiedene Systeme rhythmischer F?llung von Silberchromat wurden in einer Mischung von Agar und Gelatinegelen unter verschiedenen Umgebungsbedingungen erzeugt. Ringsysteme von Kupfer, Silber und anderen Ferricyaniden in Gelatine wurden untersucht. Die Beobachtungen zeigen, da? die Ursache für die „umgekehrten“Liesegang-Ringe in der hohen Peptisierbarkeit der Füllsubstanz im gelhaltigen Medium und den noch nicht reagierten Ionen liegt.

     

Effect of the three-body force on triton asymptotic normalization constants by the hyperspherical harmonics expansion method

We investigate the change in the calculated value of asymptotic normalization constant (ANC) by the hyperspherical harmonics expansion method with the inclusion of three nucleon force (3BF) in addition to two nucleon force. We see that ANC does not change very much with the inclusion of 3BF indicating that the 3BF does not alter the asymptotic behaviours of HHE wavefunction significantly.     

Efficiency of connected binary block designs when a single observation is unavailable

In this paper the problem of finding the design efficiency is considered when a single observation is unavailable in a connected binary block design. The explicit expression of efficiency is found for the resulting design when the original design is a balanced incomplete block design or a group divisible, singular or semiregular or regular with ₁>0, design. The efficiency does not depend on the position of the unavailable observation. For a regular group divisible design with ₁>0, the efficiency depends on the position of the unavailable observation. The bounds, both lower and upper, on the efficiency are given in this situation. The efficiencies of designs resulting from a balanced incomplete block design and a group divisible design are in fact high when a single observation is unavailable.The work of the first author is sponsored by the Air Force Office of Scientific Research under Grant AFOSR-90-0092.On leave from Indian Statistical Institute, Calcutta, India. The work of the third author was supported by a grant from the CMDS, Indian Institute of Management, Calcutta.     

Impact parameter study in multiparticle production at 70 GeV/c

This paper presents a study of the experimental lower boundb _L, on the root-mean-squared impact parameter of the multiparticle production in 70 GeV/c p-nucleon interaction. It has been observed that theb _L decreases with increasing final state multiplicity (n) at this fixed energy. The results are in good agreement with those of other authors.The authors would like to thank Prof. K. D. Tolostov of Dubna, U.S.S.R. for kindly supplying the exposed emulsion plates.     

Buckling of laminated plates - A simple finite element based on higher-order theory

A four-noded rectangular element with seven degrees of freedom at each node is developed for buckling analysis of laminated plate structures having any number of layers with a constant thickness of individual layers. The displacement model is so chosen that it can explain adequately the parabolic distribution of transverse shear stresses and the non-linearity of in-plane displacements across the thickness. A geometrical stiffness matrix is developed using in-plane stresses. A wide range of plates from thick to thin are examined under uniaxial loading conditions. The results are compared with the existing analytical and numerical solutions. The present formulations confirm its applicability for buckling analysis of a wide range of plates.     

Tracks of 18·56 MeV/u 40Ar ions in Lexan polycarbonate detector

Latent damage tracks of energetic⁴⁰Ar ions (18·56 MeV/u) have been recorded in Lexan polycarbonate detector. Bulk and track-etch parameters are evaluated under successive chemical etching. Our results show a linear correlation between the measured track-etch rate along the track and the corresponding total energy-loss rate and predict a threshold value of 5·0 MeV mg⁻¹ cm² for track registration. Maximum etchable track lengths of⁴⁰Ar ions as a function of energies have also been measured and compared with three different sets of theoretical ranges.     

Real time addition or subtraction of two images by vector wave interferometry

The present article reports a new optical method for real time addition or subtraction of two photographic images. Two transparencies which are placed in the two arms of a Mach-Zehnder interferometer with two orthogonal polarizers are subsequently added or subtracted by rotating an analyser inserted in the output beam. A linear combination of the amplitudes of the two images can also be observed for different orientations of the transmission axis of the analyser. Some experimental results are presented.