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A mathematical model is developed to examine the effects of radiation and slanted magnetic on boundary layer flow of a micropolar fluid containing gyrostatic microorganisms through a vertical fixed or continuous moving porous plate. The governing boundary layer equations are cast into a matrix form and solved analytically by utilizing the state space approach and the inversion of the Laplace transform is carried out, utilizing numerical approach. Numerical outcomes for the momentum, microrotation, density of motile microorganism and temperature distributions are given and illustrated graphically for the problem. Excellent agreement is found when present solutions are compared with the numerical solutions by utilizing the Crank–Nicolson implicit finite difference method. It is found that the density of the motile microorganisms is increasing functions of the bioconvection Lewis number in both cases moving and fixed plate. [ABSTRACT FROM AUTHOR]

Biodegradable hybrid composites Chitosan/para-phenylenediamine (CS/pPDA), montmorillonite/chitosan/para-phenylenediamine (Mt/CS/pPDA), chitosan/ortho-phenylenediamine (CS/oPDA) and montmorillonite/chitosan/ortho-phenylenediamine (Mt/CS/oPDA) clay polymer nanocomposites (CPN) were successfully synthesized. The CPN composites were confirmed by using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), UV–Vis spectroscopy and photoluminescence (PL) measurements. The nonlinear optical properties (NLO) of CPN were studied by using Z-scan technique in the picosecond (ps) and femtosecond (fs) durations. Open aperture Z-scan studies revealed reverse saturable absorption (RSA) behavior, which gives nonlinear absorption and closed aperture data revealed nonlinear refraction in both time domains. Sign and magnitude of the third order nonlinearity were evaluated. Optical limiting characteristics of the systems for optical switching were examined. Hence, the new CPN can be used as optical limiters. [ABSTRACT FROM AUTHOR]