Motion of a rigid plastic cantilever in a damping medium under transverse impact

The motion of a rigid plastic cantilever beam which is surrounded by a damping medium and struck transversely at the tip by a moving mass is studied. The elementary theory, which disregards effects due to rate of straining and geometry changes is used. The governing equations of motion are integrated numerically. For comparison the case of discrete damping provided at the tip only is also solved. Results are presented for a wide range of parameters.     

The total hadronic cross section for e+e− annihilation between 3.1 and 4.8 GeV center of mass energy

Using the solenoidal magnetic detector PLUTO, we have measured the total cross section for e⁺e^? annihilation into hadrons. Results are presented for center of mass energies between 3.6 and 4.8 GeV, and in the regions of the $\text{J}\text{ψ}$(3.1) and ψ(3.7) resonances. We also present results for the 2 prong cross section in the energy range 3.6 to 4.8 GeV.     

Relativistic effects in nuclear motions

Using the wave functions of the relativistic equivalent harmonic oscillator recently proposed, elastic electron scattering cross sections have been calculated in the Born approximation for helium and lead. Calculations have also been made with the non-relativistic isotropie oscillator wave functions. Comparison with high-energy electron scattering experiments shows that relativistic effects may be significant in a heavy nucleus like lead.     

A new method of producing local enhancement of buoyancy in liquid flows

We describe here a novel method of generating large volumetric heating in a liquid. The method uses the principle of ohmic heating of the liquid, rendered electrically conducting by suitable additives if necessary. Electrolysis is prevented by the use of high frequency alternating voltage and chemically treated electrodes. The technique is demonstrated by producing substantial heating in an initially neutral jet of water. Simple flow visualisation studies, made by adding dye to the jet, show marked changes in the growth and development of the jet with heat addition.Also with National Aeronautical Laboratory, Bangalore 560 017, India     

The influence of geostrophic force on the stability of an heterogeneous conducting fluid with a radial gravitional force

The linear and nonlinear stability of a heterogeneous incompressible inviscid perfectly conducting fluid between two cylinders is investigated in the presence of a radial gravitational force and geostrophic force. The stability for linear disturbances is investigated using the normal mode method, while the nonlinear stability is investigated by applying the energy method. In the case of linear theory, it is found that a necessary condition for in stability is that the algebraic sum of hydrodynamic, hydromagnetic and rotation Richardson number is less than one quarter somewhere in the fluid. A semi-circle theorem similar to that of Howard is also obtained. In the case of nonlinear disturbances a universal stability estimate namely a stability limit for motions subject to arbitrary nonlinear disturbances is obtained in the form $$E \leqslant E_0 \exp ( - 2M\tau ).$$ The motion is asymptotically stable if $$\delta \leqslant 1 + J_m + J_H $$ somewhere in the fluid. This asymptotic stability limit is improved using the calculus of variation technique. We also find that whenδ=1/4, andJ _R=1, both the linear and nonlinear stability criteria coincide and in that particular case, we have a necessary and sufficient condition for stability.     

Non-stoichiometry induced by differential oxygen/lone pair occupation in chiral bicyclic 1,1'-binaphthoxy cyclodiphosphazanes

Non-stoichiometry and isostructurality in a set of chiral phosphorus compounds as a result of lone pair/oxygen exchange, substantiated by the combined use of 31P NMR spectroscopy and X-ray crystallography, is described.     

Liquid mixture excess properties by the hard sphere model

The excess properties of mixing were calculated for seven systems Ar-CH₄; Ar-N₂; Ar-O₂; Ar-CO; CO-CH₄; O₂-N₂; N₂-CO, using the Caranhan and Starling equation of state of rigid spheres and the Longuet-Higgins and Widom model. Two sets of calculations were done one using the experimentalG ^E to calculateS ^E ,H ^E andV ^E , and the other making use of Miller’s cross parameter values. The calculated values are compared with those of Snider and Herrington and Miller’s values and also with the experimental values. The agreement was found to be good.     

Internal Bremsstrahlung from14C and36Cl

The Internal Bremsstrahlung (IB) spectra emitted in the beta decays of¹⁴C and³⁶Cl are measured with a HPGe detector and a multichannel analyser along with a standard geometrical set up. The experimental results are compared with the corresponding theoretical distributions due to Knipp and Uhlenbeck and Bloch (KUB), Lewis and Ford, Nilsson and also due to Chang and Falkoff. The total IB yields of intensity and of energy from each of the isotopes in the investigated energy regions are also determined and compared with the corresponding theoretical values. The present results of IB from¹⁴C are found to be in excess over all the corresponding theoretical distributions throughout the investigated photon energy region from 60 keV to 130 keV. It may also be pointed out that the IB from this isotope has not been studied earlier and as such the results in this case are considered new and important. In the case of³⁶Cl the experimental results are found to be above KUB theory but corresponding closely to the theory of Chang and Falkoff, except below 150 keV where there is experimental excess over theory.