Comparison of cellulose nanocrystal (CNC) filler on chemical,mechanical, and corrosion properties of epoxy-Zn protective coatings for mild steel in 3.5% NaCl solution

Cellulose - This present work evaluated the influence of oil palm frond cellulose nanocrystal (OPF-CNC) as a nanofiller to improve the barrier protection of the epoxy-Zn coating to lessen the...     

Photoluminescence and thermoluminescence properties of SnO2 nanoparticles embedded in Li20-K20-B203 with Cu-doping

Cu-doped borate glass co-doped with SnO2 nanoparticles is fabricated by melt quenching. The structure and morphology of the samples are examined by X-ray diffraction and field emission scanning electron microscopy. Up-conversion enhancement is observed in the photoluminescence （PL） and thermolumines- cence （TL） intensities of the glass. PL emission spectra are identified in the blue and green regions, and a fourfold increase in emission intensity may be observed in the presence of embedded SnO2 nanoparticles. The glow curve is recorded at 215℃, and fourfold increases in TL intensity are obtained by addition of 0.1 mol% SnO2 nanoparticles to the glass. Higher TL responses of the samples are observed in the energy range of 15-100 KeV. At energy levels greater than -0.1 MeV, however, flat responses are obtained. The activation energy and frequency factor of the second-order kinetic reaction are calculated by the peak shape method.     

Squeezed Atom Laser for Bose-Einstein Condensate with Minimal Length

We study a protocol for constructing a squeezed atom laser for a model originating from the generalized uncertainty principle. We show that the squeezing effects arising from such systems do not require any squeezed light as an input, but the squeezing appears automatically because of the structure of the model it owns. The output atom laser beam becomes squeezed due to the nonlinear interaction between the Bose-Einstein condensate and the deformed radiation field created due to the noncommutative structure. We analyze several standard squeezing techniques based on the analytical expressions followed by a numerical analysis for further insights.

     

Plant residual time modelling based on observed variables in oil samples

This paper presents a model and methodology for estimating the residual time of a plant item. This plant item can be an engine or any complex technical system monitored by a regularly spaced oil analysis programme. Typically in the oil samples taken, two groups of observed variables are available, namely, metal concentrations and variables related to the condition of the lubricant and contaminants. We term the former as internal variables and the latter as external variables. External variables are those that may cause the change of the underlying condition of the plant item and therefore the residual time, while internal variables are those variables that only reflect the residual time but cannot change it. We modelled both variables in an oil-based monitoring case, but the principle can be generalized to other monitoring situations. The main techniques used are stochastic filtering for residual time prediction and the maximum likelihood method for parameters estimation. The model established was fitted to the real data of marine diesel engines monitored by an oil analysis programme and the results are presented.     

Nonlinear differential equations and lie superalgebras

It is shown how the theory of nonlinear ordinary differential equations with superposition formulas can be generalized to the case of superequations involving anticommuting Grassmann variables. As an example, equations based on the osp(1, 2) superalgebra are analyzed in detail. They turn out to be super-Riccati equations and a super-superposition formula is obtained for their solutions.

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Résumé Nous montrons comment la théorie des équations différentielles ordinaires non-linéaires admettant des lois de superposition peut être généralisée au cas de super-équations contenant des variables de Grassmann anticommutantes. Comme exemple les équations basées sur la super-algèbre osp(1, 2) sont analysées en détail. Nous obtenons des super-équations de Riccati et leurs formules de superposition sont mises en évidence.

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Chargé de recherches du FNRS.     

Enantio-, Regio-, and Chemoselective Reduction of Aromatic a-Diketones by Baker’s Yeast

The enantio- and regioselective reduction of several symmetric and nonsymmetrically para-substituted benzil derivatives (21–92%) was achieved by means of Saccharomyces cerevisiae (bakers yeast). After modification of the reaction conditions reduction of nonsymmetric -diketones led chemoselectively to chiral -hydroxy ketones with up to 82% ee.