Study of Dissipative Collisions of 20^{20}Ne (∼\sim7-11 MeV/nucleon) + 27^{27}Al

The inclusive energy distributions of complex fragments (3 $\leq$Z $\leq$ 9) emitted in the reactions $^{20}$Ne (145, 158, 200, 218 MeV) + $^{27}$Al have been measured in the angular range 10$^{o}$ - 50$^{o}$. The fusion-fission and the deep-inelastic components of the fragment yield have been extracted using multiple Gaussian functions from the experimental fragment energy spectra. The elemental yields of the fusion-fission component have been found to be fairly well exlained in the framework of standard statistical model. It is found that there is strong competition between the fusion-fission and the deep-inelastic processes at these energies. The time scale of the deep-inelastic process was estimated to be typically in the range of $\sim$ 10$^{-21}$ - 10$^{-22}$ sec., and it was found to decrease with increasing fragment mass. The angular momentum dissipations in fully energy damped deep-inelastic process have been estimated from the average energies of the deep-inelastic components of the fragment energy spectra. It has been found that, the estimated angular momentum dissipations, for lighter fragments in particular, are more than those predicted by the empirical sticking limit.Comment: 16 pages, 9 figure

Global Properties of the Globular Cluster Systems of Four Spiral Galaxies

We present results from a wide-field imaging study of the globular cluster (GC) systems of a sample of edge-on, Sb-Sc spiral galaxies ~7-20 Mpc away. This study is part of a larger survey of the ensemble properties of the GC populations of giant galaxies. We imaged the galaxies in BVR filters with large-format CCD detectors on the WIYN 3.5-m telescope, to projected radii of ~20-40 kpc. For four galaxies (NGC 2683, NGC 3556, NGC 4157, and NGC 7331), we quantify the radial distributions of the GC systems and estimate the total number, luminosity- and mass-normalized specific frequencies (S_N and T), and blue (metal-poor) fraction of GCs. A fifth galaxy (NGC 3044) was apparently too distant for us to have detected its GC system. Our S_N for NGC 2683 is 2.5 times smaller than the previously-published value, likely due in part to reduced contamination from non-GCs. For the spiral galaxies analyzed for the survey to date, the average number of GCs is 170+/-40 and the weighted mean values of S_N and T are 0.8+/-0.2 and 1.4+/-0.3. We use the survey data to derive a relationship between radial exent of the GC system and host galaxy mass over a factor of 20 in mass. Finally, we confirm the trend, identified in previous survey papers, of increasing specific frequency of metal-poor GCs with increasing galaxy mass. We compare the data with predictions from a simple model and show that carefully quantifying the numbers of metal-poor GCs in galaxies can constrain the formation redshifts of the GCs and their host galaxies.Comment: 30 pages, including 14 figures and 13 tables; accepted for publication in The Astronomical Journal, Oct 2007 issu

Biferroic YCrO3

YCrO3 which has a monoclinic structure, shows weak ferromagnetism below 140 K (TN) and a ferroelectric transition at 473 K accompanied by hysteresis. We have determined the structure and energetics of YCrO3 with ferromagnetic and antiferromagnetic ordering by means of first-principles density functional theory calculations, based on pseudopotentials and a plane wave basis. The non-centrosymmetric monoclinic structure is found to be lower in energy than the orthorhombic structure, supporting the biferroic nature of YCrO3.Comment: 16 pages including figure

Electrochemical Oxidation of Methanol, Formic Acid & Hydrazine at Pt-Ni, Pt-Au & Pt-Pd Electrodes

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Seed yield of linseed varieties grown as ‘paira’ crop as influenced by dates of sowing

Linseed is an industrial crop cultivated for its seeds, fibres and oil purpose. Linseed crop can met their requirement i.e. moisture and nutritional demand from stored soil moisture and residual fertility status in "utera? or "paira? system of cropping. On the basis of this fact an experiment was conducted on “Seed yield of linseed varieties grown as paira crop as influenced by dates of sowing” in red and laterite zone of West Bengal during rabi season of 2012-13 and 2013-14 at Rice Research Station, Bankura, West Bengal, India. Poor in organic matter content, available phosphate and bases, hard structure of iron and aluminium patterned as honeycomb are present in the subsurface regions of the profiles and kaolinite is the predominant clay minerals of red and lateritic zone (western part) of West Bengal. This experiment was laid out in a split-plot design with three replications and compared two factors (dates of sowing and linseed varieties). Objective was identifying the optimum date of sowing and suitable linseed varieties grown as „paira? crop under changed climate in red and laterite zone of West Bengal. The experimental results revealed that the highest seed yield (534 kg ha-1 as pooled value) was recorded from the treatment D1 i.e. linseed sown on 15th November. The lowest seed yield (489.2 kg ha-1 as pooled value) was obtained with treatment D3 i.e. linseed sown on 29th November. Among linseed varieties, T-397 has yielded highest seed yield (573.4 kg ha-1 as pooled value). Lowest seed yield (409. 3 kg ha-1 as pooled data) was recorded from Neela variety. From the present study it may be concluded that linseed sown on 15th November is the best time and T-397 is the suitable linseed variety grown as "paira? crop under changed climate in red and laterite zone of West Bengal

Dissipation of angular momentum in light heavy ion collision

The inclusive energy distributions of fragments (4$\leq$Z$\leq$7) emitted in the reactions $^{16}$O (116 MeV) + $^{27}$Al, $^{28}$Si, $^{20}$Ne (145 MeV) + $^{27}$Al, $^{59}$Co have been measured in the angular range $\theta_{lab}$= 10$^\circ$ - 65$^\circ$. Fusion-fission and deep inelastic components of the fragment emission have been extracted from the experimental data. The angular mometum dissipations in fully damped deep inelastic collisions have been estimated assming exit channel configuration similar to those for fusion-fission process. It has been found that, the angular momentum dissipations are more than those predicted by the empirical sticking limit in all cases. The deviation is found to increase with increasing charge transfer (lighter fragments). Qualitatively, this may be due to stronger friction in the exit channel. Moreover, for the heavier system $^{20}$Ne + $^{59}$Co, the overall magnitude of deviation is less as compared to those for the lighter systems, {\it i.e.}, $^{16}$O + $^{27}$Al, $^{28}$Si, $^{20}$Ne + $^{27}$Al. This may be due to lesser overlap in time scales of fusion and deep inelastic time scales for heavier systems.Comment: 15 pages, 9 figures, accepted for publication in Phys. Rev.

Evidence of large nuclear deformation of 32^{32}S∗^{*} formed in 20^{20}Ne + 12^{12}C reaction

Deformations of hot composite $^{32}$S$^{*}$ formed in the reaction $^{20}$Ne ($\sim$ 7 -- 10 MeV/nucleon) + $^{12}$C have been estimated from the respective inclusive $\alpha$-particle evaporation spectra. The estimated deformations for $^{32}$S$^{*}$ have been found to be much larger than the `normal' deformations of hot, rotating composites at similar excitations. This further confirms the formation of highly deformed long-lived configuration of $^{20}$Ne + $^{12}$C at high excitations ($\sim$ 70 -- 100 MeV) -- which was recently indicated from the analysis of the complex fragment emission data for the same system. Exclusive $\alpha$-particle evaporation spectra from the decay of hot composite $^{32}$S$^{*}$ also show similar behaviour.Comment: 9 pages, 6 figure