Criterion for a unique non-relativistic quark model

We have calculated the mean square charge radii of the neutron and proton, and compared them with the experimental values, to construct a unique non-relativistic quark potential model. It is shown for the first time that, contrary to general belief, it is possible to reproduce simultaneously the baryon mass spectrum and the electromagnetic sizes of neutron and proton using a single potential model. It was found necessary to add admixtures of excited states of the nucleon in the unperturbed ground state wavefunctions.     

Investigation of alpha particle induced reactions on thulium

Alpha particle induced reactions on the target element thulium were investigated up to 75 MeV, using foil-stack activation technique and Ge(Li) gamma ray spectroscopy method. Excitation functions for eight reactions of the type¹⁶⁹Tm(α, xn),x=1 − 4;¹⁶⁹Tm(α, pxn),x=3; and¹⁶⁹Tm(α, αxn),x=1, 2, 4 were investigated. Of these, four reactions¹⁶⁹Tm(α, p3n),¹⁶⁹Tm(α, αn),¹⁶⁹Tm(α, α2n)¹⁶⁹Tm(α, α4n), were studied for the first time and in the remaining four reactions, some 19 new energy-point cross-sections were measured for the first time. The experimental cross-sections were compared with the predictions of pre-equilibrium hybrid model, as well as the more recent index model, using the initial excition number,n ₀=4 (4p0h). Both the models show better agreement in respect of (α, xnyp) type of reactions. However they are equally bad for (α, αxn) type of reactions which involve theα-particle in the exit channels, and for which some direct reaction contributions are indicated.     

Mean lifetime measurements of F II and F III levels using beam-foil technique

Beam-foil spectrum of fluorine was recorded in the wavelength region of 2000–4500 Å using F⁺ ion beams of energies ranging from 216 to 296 KeV. Some of the spectral lines of fluorine observed during the present investigation are hitherto unknown. Mean lifetimes of a few of the excited levels of F II and F III are reported for the first time.     

Equilibrium characteristics of strong ion sheaths in a partiallyionized plasma

Experiments have been carried out to study the equilibrium characteristics of strong ion sheaths (eΦ/T_e≫1) in a partially ionized argon plasma. An improved method of potential measurement in the sheath is described. The potential profile shows deviations from Child's law and the reduction of sheath size with pressure. Energy analysis of ions reaching the negative biased electrode show that the ions are not monoenergetic but have a spread in energies which depends on neutral pressure     

Cosmological models consistent with supersymmetric compactiflcation of superstring theories

The compactification of 10-dimensional supergravity, coupled to super Yang-Mills theory, to curved 4-dimensional spacetimes is investigated. The requirement of unbroken supersymmetry leads to a set of consistency conditions. These are fairly restrictive, but nevertheless permit some nontrivial solutions, including the Milne universe. More general time-dependent metrics are also not ruled out.     

How well does dual photon absorptiometry predict osteoporosis? A comparison between neutron activation analysis and DEXA

The accuracy of dual energy X-ray absorptiometry (DEXA) for measurement of bone mass carried out by quantitative digital radiography (Hologic Inc.) was compared to results with neutron activation analysis (NAA) on 106 subjects. The accuracy with DEXA was further investigated by measurements on aluminium samples of known composition. DEXA measured 4 lumbar vertebrae by spine scan. The central third of the skeleton also was measured by whole body scan to obtain data on the same large part of the skeleton as measured by NAA. Results suggested that DEXA spine scans were more reliable than whole body scans. In addition, the measurement of total mineral content (BMC) was more reliable than the normalization of BMC to bone surface area (BMC/Area) or bone mineral density (BDM). Since the proportion of bone below detection would increase with development of osteoporosis, with osteoporosis the BMC would be increasingly underestimated, but to only a small extent, while the BMD would be more significantly overestimated.     

Complexes of N, S donor ligands. CoII, CoIII, MnIII, FeIII and PdII complexes of 1, 2-di( o -aminophenylthio)ethane: Synthesis, characterisation and reactions

The ligand 1,2-di(o-aminophenylthio)ethane (abbreviated as H₂DAPTE) has been allowed to react with various metal salts and the complexes isolated and characterised. In these complexes, H₂ DAPTE behaves as a neutral quadridentate and also as a dibasic quadridentate ligand after losing two protons from the amine functions. Two complexes of this ligand, reported earlier, have been condensed with acetone to form macrocyclic complexes of TDDH where TDDH is 13, 13, 15-trimethy1-2,5-dithia-12, 16-diazatricyclo-[15,3,0,0,6,11]-docosa-1(17), 6(11), 7,9,15,18,20-heptene.