Manganese(III) acetate mediated oxidation of aporphines: a convenient and useful synthesis of oxoaporphines

Manganese(III) acetate mediated oxidation of aporphines to oxoaporphines is described. The developed methodology was conveniently applied for the synthesis of naturally occurring oxoaporphine alkaloids, oxoglaucine, and atheroline, starting from commercially available boldine.     

Sample preparation for evaluation of detection limits in X-ray fluorescence spectrometry.

The influence of analyte mass concentration on determination of detection limits in X-ray fluorescence spectrometry has been investigated experimentally. Both the total reflection X-ray fluorescence (TXRF) and the conventional energy-dispersive X-ray fluorescence techniques have been used to derive the dependence of analyte mass concentration on the values of detection limits. Results obtained indicate that values of detection limits are optimum, or in other words, they are closer to the true detection limit of the technique, when analyte concentrations are in the range of 10 times of the detection limit.     

A comparative study of indoor radon level measurements in the dwellings of Punjab and Himachal Pradesh, India

The LR-115 type-II plastic track detector has been used for measuring the indoor radon levels in the dwellings of some villages of Punjab and Himachal Pradesh. In Punjab, the villages surveyed are Rampura Phul, Lehra Mahabat and Pitho (villages in Bathinda district), and Amritsar city. The average indoor radon levels in these areas are found to vary from 64 to 152 Bq/m³, which are quite within the safe limits recommended by International Commission on Radiological Protection (Ann. ICRP 23(2)). The indoor radon levels have also been measured in the dwellings of Hamirpur district of Himachal Pradesh. The villages surveyed in this area are Nukhel, Badarn, Galore-Khas, Har-Upper, Tikker Brahamana and Awah-Lower where radon concentration has been found to vary from 261 to 724 Bq/m³. These values are higher than the recommended limit.     

Characterization of some new alkali metal molybdate hydrates by thermal and X-ray methods

Preparation and characterization of four new hydrated alkali metal molybdates Na₂Mo₄O₁₃·6H₂O, K₂Mo₄O₁₃·3H₂O, Rb₂Mo₄O₁₃·2H₂O and Cs₂Mo₄O₁₃·2H₂O are described. The compounds were prepared by crystallizing the solution obtained by dissolving MoO₃ and corresponding alkali metal carbonates A₂CO₃ or molybdate A₂MoO₄ in stoichiometric amount in distilled water. The hydrated molybdates were characterized by thermal (TG/DTA) and X-ray diffraction (XRD) methods. The number of water molecules in the compounds were determined from their TG /DTA curves recorded in air and identification of their dehydration products was done by XRD. The cell parameters of the compounds were obtained by indexing their XRD patterns. Attempt to prepare the corresponding hydrated compound of lithium was not successful. This revised version was published online in July 2006 with corrections to the Cover Date.     

Robust control of chaos in Chua’s circuit based on internal model principle

The paper treats the question of robust control of chaos in Chua’s circuit based on the internal model principle. The Chua’s diode has polynomial non-linearity and it is assumed that the parameters of the circuit are not known. A robust control law for the asymptotic regulation of the output (node voltage) along constant and sinusoidal reference trajectories is derived. For the derivation of the control law, the non-linear regulator equations are solved to obtain a manifold in the state space on which the output error is zero and an internal model of the k-fold exosystem (k = 3 here) is constructed. Then a feedback control law using the optimal control theory or pole placement technique for the stabilization of the augmented system including the Chua’s circuit and the internal model is derived. In the closed-loop system, robust output node voltage trajectory tracking of sinusoidal and constant reference trajectories are accomplished and in the steady state, the remaining state variables converge to periodic and constant trajectories, respectively. Simulation results are presented which show that in the closed-loop system, asymptotic trajectory control, disturbance rejection and suppression of chaotic motion in spite of uncertainties in the system are accomplished.     

Beyond the standard model: Working group report

This report summarises the activities of the working group on ‘Physics beyond the Standard Model’. The results of investigations in incorporatingR-parity in grand unification, the possibility of a light charged Higgs boson in extension of MSSM and radiative generation of neutral vector boson self-couplings within the MSSM are described. Also given is an account of activities in neutrino physics, namely a proposal for a study of the atmospheric muon anomaly in deep underground mines, a field theoretic study of neutrino oscillations and a mechanism to generate appropriate masses of three active plus one sterile neutrino species.     

Intranuclear cascading at ultrahigh energy in heavy-ion interactions

Intranuclear cascading mechanism one of the important non-linear effects in high energy nucleusnucleus collisions is investigated. The data on multiplicity (n _s ) and pseudorapidity (η) distributions of shower particles produced by³²S and¹⁶O at 200A GeV,¹⁶O at 60A GeV,²⁸Si at 14.5A GeV and He at ≈140A GeV are presented and compared with the string model VENUS, which takes into account the cascade interactions of secondary particles. The effect of the intranuclear collisions on the distributions of <η> versus <n _s > is discussed for all the beams.     

High spin states in120Xe

High spin states in ¹²⁰Xe, populated via¹⁰⁷Ag(¹⁶O, p2n) and¹⁰⁸Pd(¹⁶O, 4n)reactions have been studied using γ-ray spectroscopic techniques. 21 new transitions have been added to extend the level scheme. Two S-bands are extended upto 26⁺ and 22⁺;these bands are found to cross the g. s band at hΩ=0. 39 and 0. 47 MeV. The band structures have been discussed within the framework of CSM.