Mach-Zehnder interferometer-based tree architecture for all-optical logic and arithmetic operations

Interferometric devices for optical processing have been of great interest in recent years. Semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer (MZI) has already taken a significant role in the field of ultra-fast all-optical signal processing. Optical tree architecture (OTA) provides important contributions in optical interconnecting networks. In this communication, we have tried to exploit the advantages of both OTA and SOA-based MZI switches. We have proposed SOA-MZI-based tree architecture, a new and alternative scheme, for integrated all-optical logic and arithmetic operations. This architecture can enable one to perform all-optical processing of signals, including two input logic operations, half-adder, full-adder, full-subtractor, one-bit data comparator, etc.     

On generalisations of Stieltjes transform

In this paper two different generalisations of the Stieltjes transform have been given along with their inversion formulae. The results are given in the form of two theorems. These two theorems yield many known generalisations of the transform in question as particular cases on specializing the parameters involved therein.     

Synthesis and 1H NMR studies of paramagnetic nickel(II) complexes containing bis(pyrazolyl)methane ligands with dendritic substituents

The substituted bis(pyrazolyl)methane ligands RCH(3,5-Me2pz)2(R=SiMe3, CH2Ph, G1, G2, and G3; Gn=Fréchet-type dendritic wedges of generation n) have been prepared starting from H2C(3,5-Me2pz)2. Reaction of these didentate ligands with [NiBr2(DME)] is a straightforward procedure that allows the synthesis of the nickel(II) complexes [NiBr2{RCH(3,5-Me2pz)2}]. The molecular structure of compound (R=CH2Ph) has been determined by X-ray diffraction studies. The nickel centre coordinates two bromine and two nitrogen atoms in a tetrahedral environment, and the metallacycle Ni(NN)2C adopts a boat conformation with the benzyl group in an axial position. 1H NMR studies have been carried out to characterize these paramagnetic nickel compounds in solution. Valuable information about the disposition of the ligands and dendritic wedges in solution has been obtained thanks to the influence of the paramagnetic centre on the proton resonances.     

Removal of Brilliant Green from wastewater using conventional and ultrasonically prepared poly(acrylic acid) hydrogel loaded with kaolin clay: A comparative study

The present work deals with the removal of Brilliant Green dye from wastewater using a poly(acrylic acid) hydrogel composite (PAA-K hydrogel) prepared by incorporation of kaoline clay. The composite has been synthesized using ultrasound assisted polymerization process as well as the conventional process, with an objective of showing the better effectiveness of ultrasound assisted synthesis. It has been observed that the hydrogel prepared by ultrasound assisted polymerization process showed better results. The optimum conditions for the removal of dye are pH of 7, temperature of 35 °C, initial dye concentration of 30 mg/L and hydrogel loading of 1 g. The extent of removal of dye increased with an increase in the contact time and initial dye concentration. A pseudo-second-order kinetic model has been developed to explain the adsorption kinetics of dye on the PAA-K hydrogel. Thermodynamic and kinetic parameters indicate that the adsorption process is spontaneous in nature and the PAA-K hydrogel prepared by ultrasound process is a promising adsorbent compared to conventional process. The obtained adsorption data has also been fitted into commonly used adsorption isotherms and it has been found that Freundlich as well as Langmuir adsorption isotherm models fits well to the experimental results.     

Micro‐Raman investigation of nanosized zinc ferrite: effect of crystallite size and fluence of irradiation

Zinc ferrite nanoparticles of different sizes ranging from 12 to 62 nm were synthesized by using the nitrate route. These nanoparticles were irradiated by a 100 MeV oxygen beam at two fluences: 1 × 10¹³ and 5 × 10¹³ ions/cm². It was observed that modes corresponding to cubic spinel phase were retained after the irradiation in all the systems. The variation in the parameters of various modes follows phonon confinement, while this effect seems to violate in irradiated specimen. It was found that the irradiation‐induced changes in the modes F_2g(2) and F_2g(3) depend on whether the crystallite size of the pristine sample is less than, equal to or greater than the phonon confinement length, while this length is not dominant for the irradiation‐induced changes in the mode A_1g. The changes in various parameters of the modes are attributed to the combined effect of the restructuring of the chemical species and ion‐induced defects. Copyright © 2011 John Wiley & Sons, Ltd.     

Structural and morphological studies on the deformation behavior of polypropylene/multi‐walled carbon nanotubes nanocomposites prepared through ultrasound‐assisted melt extrusion process

Structural and morphological behavior under stress–strain of polypropylene/multi‐walled carbon nanotubes (PP/MWCNTs) nanocomposites prepared through ultrasound‐assisted melt extrusion process was studied by means of optical microscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, small angle X‐ray scattering (SAXS), and wide angle X‐ray scattering (WAXS). A high ductile behavior was observed in the PP/MWCNT nanocomposites with low concentration of MWCNTs. This was related to an energy‐dissipating mechanism, achieved by the formation of an ordered PP‐CNTs interphase zone and crystal oriented structure in the undeformed samples. Different strain‐induced‐phase transformations were observed by ex situ SAXS/WAXS, characterizing the different stages of structure development during the deformation of PP and PP/MWCNTs nanocomposites. The high concentration of CNTs reduced the strain behavior of PP due to the agglomeration of nanoparticles. A structural pathway relating the deformation‐induced phase transitions and the dissipation energy mechanism in the PP/MWCNTs nanocomposites at low concentration of nanoparticles was proposed. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 475–491     

Detection of blood flow through artery in the presence of steno-occlusive disease post liver transplantation by modeling for theatrical and detrimental environmental changes

This research intends to expand a mathematical model for studying the non-Newtonian surge of blood through a hepatic artery in the presence of steno occlusive disease post-liver transplantation. Power law liquid demonstrates the non- Newtonian character of blood. The hemodynamic conduit of the fluid is altered by the occurrence of arterial stenosis. In our study, the difficulty is resolved by applying diagnostic methods with the assistance of marginal circumstances and consequences. The outcomes are explained graphically for unusual cases for such stenosis. The study design is based on a tensorial form and converts its solution using numerical and analytical techniques. Our study outcome suitably demonstrates that the mathematical model used corroborates with the clinical scenario of the patient with hepatic disease.     

CZTS counter electrode in dye-sensitized solar cell: enhancement in photo conversion efficiency with morphology of TiO2 nanostructured thin films

Journal of Solid State Electrochemistry - In the present investigation, kesterite phase Cu2ZnSnS4 (CZTS) nanoparticle, and one-dimensional (1D) nanorods and three-dimensional (3D) flower-like...     

Soft hydrogen bonds to alkenes: the methanol–ethene prototype under experimental and theoretical scrutiny

An FTIR spectroscopic study of the elusive hydrogen-bonded methanol–ethene complex, the most elementary example for weak intermolecular alcohol hydrogen bonding to a π cloud, is presented. By isolating the complex in a supersonic jet, the rigorous comparability to high-level quantum chemical calculations is ensured. In stark contrast to classical hydrogen bonds, experimental overtone analysis reveals the harmonic oscillator approximation for the OH red shift to be accurate. Harmonic calculations up to explicitly correlated local coupled-cluster level are thus found to agree very well with experiment. The experimental OH values for the red shift (45 cm^–1), the small change in diagonal anharmonicity (–3 cm^–1) and the overtone intensity attenuation (2 × 10²-fold) together with theoretical predictions for the preferred structural arrangement and the zero-point-corrected dissociation energy (8 kJ mol^–1) may thus be regarded as definitive reference values for related systems and for more approximate computational methods. In particular, MP2 calculations are shown to fail for this kind of weak intermolecular interaction.