Temperature dependence of second order Raman spectra of rubidium iodide crystal

The temperature variation of the second order Raman spectra of RbI has been theoretically studied in three basic symmetries on the basis of the modified Born and Bradburn theory. The phonon frequencies and corresponding eigenvectors have been determined at the room temperature by employing a three body force shell model. It has been assumed that the major factor which governs the temperature dependence of Raman intensity is the occupation number and the changes in the phonon eigen data and the polarizability parameters with temperature have been ignored. Calculations have been made at three temperatures namely, 300,90 and 23 K and the theoretical results have been compared to the experimental Raman spectra.     

Performance limitations of flat-histogram methods

We determine the optimal scaling of local-update flat-histogram methods with system size by using a perfect flat-histogram scheme based upon the exact density of states of 2D Ising models. The typical tunneling time needed to sample the entire bandwidth does not scale with the number of spins N as the minimal N2 of an unbiased random walk in energy space. While the scaling is power law for the ferromagnetic and fully frustrated Ising model, for the +/-J nearest-neighbor spin glass the distribution of tunneling times is governed by a fat-tailed Fréchet extremal value distribution that obeys exponential scaling. Furthermore, the shape parameters of these distributions indicate that statistical sample means become ill defined already for moderate system sizes within these complex energy landscapes.     

Effect of supersaturation on the viscosity of solutions

Ohne Zusammenfassung     

Heterocyclic compounds. XI. Potential post-coital antifertility agents

A series of heterocyclic analogs of diarylethylene and triarylethylene were synthesized as potential anti-implantation agents. Tested in rats as oral, post-coital antifertilily agents, a few of our compounds showed some activity.     

Note on the boundary layer on a rotating

Ohne Zusammenfassung

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Miscellaneous

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Divers

     

Poly-β-hydroxybutyrate Production by Fast-Growing Rhizobia Cultivated in Sludge and in Industrial Wastewater

In our study, the potential of producing polyhydroxybutyrate (PHB) by cultivating fast-growing rhizobia (Sinorhizobium meliloti, Rhizobium leguminosarum bv. viciae, R. leguminosarum bv. phaseoli and R. leguminosarum bv. trifolii) in sludge and in industrial wastewater was evaluated. Results confirmed the possibility of using sludge as media for rhizobial growth. During growth, substantial quantity of PHB was accumulated and yields varied depending on the media and rhizobial species. Growing in sludge, PHB production did not exceed 3.7% w/w for all strains at the end of experiment (after 72 h). During the growth of S. meliloti, PHB yield varied and the maximum value reached 7.27% w/w after 60 h, with 1% Total Suspend Solid (TSS) sludge. Alkaline sludge pre-treatment affects rhizobial growth but did not improve the PHB accumulation. While growing S. meliloti in industrial wastewater, the PHB yields varied and the highest value was obtained with slaughterhouse wastewater (10.7% w/w) after 35 h of growth. Therefore, this work shows the potential of exploiting PHB production by rhizobia growing in wastewater or sludge which could be applied to bioplastic industry, and confirms the potential of these recyclable wastes for high production of rhizobial cells useable for legumes inoculants production. This study provides an environmentally sound way of sludge and wastewater management and use in diverse biotechnological applications.