Computer simulation of Fresnel diffraction from rectangular apertures and obstacles using the Fresnel integrals approach

In this paper, we describe a new computer simulation technique of generating Fresnel diffraction images from rectangular apertures of arbitrary dimensions by using Fresnel integrals instead of the more common fast Fourier transform methods. The simulation can be performed in almost any PC using the software MATLAB. Diffraction images can be generated for any wavelength of light and for any aperture–screen and aperture-source distances. Images for rectangular obstacles can also be simulated. Details of the algorithm and program are presented, as well as the interesting insights than can be gained from using the program. Finally, it is shown that the simulated images reduce to the simple Fraunhofer diffraction patterns for certain limiting situations.     

Conjugative,Exciton and Charge-Resonance Interactions in D2d-9,9′-Spirobifluorene and D2d-Tetrabenzotricyclo [5.5.0.02,8]dodeca-3,5,9,11-tetraene. Photoelectron and Polarized Absorption Spectra

Photoelectron spectroscopy, polarized electronic absorption spectroscopy in stretched polymer sheets, and semiempirical theoretical methods have been applied to investigate the valence electronic structures of the two title compounds 1 and 2 , considering fluorene ( 3 ) as a reference compound. The results are analyzed in terms of ‘through space’ and ‘through bond’ conjugative effects and exciton and charge-resonance interactions. Spiro-conjugation in 1 is found to play a similar role as ‘through bond’ interaction via the cyclobutane ring in 2 . In contrast to the results of a recent investigation, exciton coupling is found to be relatively insignificant, while charge-resonance effects are important. The transition close to 41 000 cm^?1 in the absorption spectra of 1 and 2 has no obvious counterpart in the spectrum of 3 ; it is assigned to a ¹E^? state with large charge-resonance character, involving promotion of an electron from the HOMO of one half-chromophore to the LUMO of the other.     

Extractives of Milletia ovalifolia

Isolation of lanceolatin B, the flavanones 1 and 2, the flavones 3 and 4 and the dibenzoylmethane 5 from M. ovalifolia is reported. The structures were assigned from spectral data and confirmed by synthesis.     

Series solution of unsteady free convection flow with mass transfer along an accelerated vertical porous plate with suction

The problem of unsteady free convection flow is considered for the series solution (analytic solution). The flow is induced by an infinite vertical porous plate which is accelerated in its own plane. The series solution expressions for velocity field, temperature field and concentration distribution are presented. The influence of important parameters is seen on the velocity, temperature, concentration, skin friction coefficient and temperature gradient with the help of graphs and tables. Convergence is also properly checked for different values of the important parametes for velocity field, temperature and concentration with the help of ħ-curves.     

Organometallic assembling of chitosan‐Iron oxide nanoparticles with their antifungal evaluation against Rhizopus oryzae

The ever‐increasing resistance of plant microbes towards fungicides and bactericides has been causing serious threat to plant production in recent years. For the development of an effective antifungal agent, we introduce a novel hydrothermal protocol for synthesis of chitosan iron oxide nanoparticles (CH‐Fe₂O₃ NPs) using acetate buffer of low pH 5.0 for intermolecular interaction of Fe₂O₃ NPs and CH. The composite structure and elemental elucidation were carried out by using X‐ray power diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X‐ray (EDX), Transmission Electron Microscopy (TEM), Fourier Transformed Infrared Spectroscopy (FTIR) and Ultraviolet Visible Absorption Spectroscopy (UV–vis spectroscopy). Additionally, antifungal activity was evaluated both In vitro and In vivo against Rhizopus oryzae which is causing fruit rot disease of strawberry. We compared different concentrations (0.25%, 0.50%, 075% and 1%) of CH‐Fe₂O₃ NPs and 50% synthetic fungicide (Matalyxal Mancozab) to figure out suitable concentration for application in the field. XRD analysis showed a high crystalline nature of the NPs with average size of 52 nanometer (nm). SEM images revealed spherical shape with size range of 50–70 nm, whereas, TEM also revealed spherical shape, size ranging from 0 nm to 80 nm. EDX and FTIR results revealed presence of CH on surface of Fe₂O₃ NPs. The band gap measurement showed peak 317–318 nm for bare Fe₂O₃ NPs and CH‐Fe₂O₃ NPs respectively. Antifungal activity in both In vitro and In vivo significantly increased with increase in concentration. The overall results revealed high synergetic antifungal potential of organometallic CH‐Fe₂O₃ NPs against Rhizopus oryzae and suggest the use of CH‐Fe₂O₃ NPs against other Phyto‐pathological diseases due to biodegradable nature.     

Nanocrystalline TiO2, via green combustion synthesis,as an efficient and reusable catalyst for the preparation of 1,8‐dioxooctahydroxanthenes and 1,8‐dioxodecahydroacridines

Nanocrystalline TiO₂ is synthesized using a green combustion method and used as a recyclable catalyst for the one‐pot multicomponent synthesis of 1,8‐dioxodecahydroacridines and 1,8‐dioxooctahydroxanthenes, under solvent‐free conditions. This method is mild, environmentally friendly, inexpensive and highly effective for obtaining good to excellent yields of the products. Copyright © 2015 John Wiley & Sons, Ltd.