Unified Split Octonion Formulation of Dyons

Demonstrating the split octonion formalism for unified fields of dyons (electromagnetic fields) and gravito-dyons (gravito-Heavisidian fields of linear gravity), relevant field equations are derived in compact, simpler and manifestly covariant forms. It has been shown that this unified model reproduces the dynamics of structure of fields associated with individual charges (masses) in the absence of others.     

Growth and characterization of KY(WO4)2 crystals

Single-crystal growth of KY(WO₄)₂ (KYW) by top-seeded solution growth technique has been investigated. The effects of seed orientation, temperature gradient experienced by the growing crystal and rate of crystallization on crystal quality are reported. The best results are obtained when the growth is seeded along the 0 1 0 direction. Minute deviations from this growth direction are found to be detrimental to crystal perfection. The differential thermal analysis shows that the amount of super-cooling required for dissolution and crystallization of KYW in the flux is only 5° and this promotes an easy formation of tiny crystallites in the solution. Consequently, the crystal rotation and the solution cooling rates are found to have pronounced effects on the growth of KYW crystal.     

Optical parameters of nanostructured thin films of?electromagnetite Pb1? x Sr x (Fe0.012Ti0.988)O3

Polycrystalline Pb_1−x Sr _x (Fe_0.012Ti_0.988)O₃ (0.2≤x≤0.4) (PSFT) thin films have been grown on fused quartz substrates by metallo-organic decomposition technique. The grown films were characterized using X-ray diffraction (XRD), atomic force microscopy (AFM), source meter and UV–Vis–NIR spectrophotometer to determine the structural, microstructural, dc resistivity and optical properties. The XRD pattern confirmed that the PSFT films has distorted tetragonal single phase, which close to cubic at higher Sr concentration. AFM analysis revealed that the grains size reduces with increasing Sr concentration and their average values lies in the range of 26–9 nm. The higher values of dc resistivity of PSFT nano grains indicate that the transmission of light occurs within these grains up to short wavelength. The refractive index and the extinction coefficient were determined from the optical transmission spectrum in the wavelength range of 200–1100 nm and compared with that theoretically calculated, when fitted to a single oscillator model. The values of optical band gap were determined from Tauc’s extrapolation fitting and suggests that the transformation of electrons during transmission of light through local states within Fermi gap.     

Quaternion Dirac Equation and Supersymmetry

Quaternion Dirac equation has been analyzed and its supersymmetrization has been discussed consistently. It has been shown that the quaternion Dirac equation automatically describes the spin structure with its spin up and spin down components of two component quaternion Dirac spinors associated with positive and negative energies. It has also been shown that the supersymmetrization of quaternion Dirac equation works well for different cases associated with zero mass, nonzero mass, scalar potential and generalized electromagnetic potentials. Accordingly we have discussed the splitting of supersymmetrized Dirac equation in terms of electric and magnetic fields.     

Modified generalized kinetic model and degradation mechanistic pathways for catalytic oxidation of NBS dye in Fenton-like oxidation process

Rice husk was utilized as a silica source for the synthesis of mesoporous silica (MS), which was further used for the surface modification of iron oxide nanoparticles (IO-NPs) to form mesoporous silica-modified iron oxide nanoparticles (MSIO-NPs). IO-NPs and MSIO-NPs were characterized using FT-IR, XRD, X-ray photoelectron spectroscopy, vibrating sample magnetometry, nitrogen adsorption–desorption, TEM and dynamic light scattering analysis. The catalytic activity of MSIO-NPs was tested for degradation and mineralization of Nile blue sulphate dye (NBS) in Fenton-like oxidation process. The degradation efficiency and total organic carbon (TOC) removal of NBS dye onto MSIO-NPs was found to be 92.46 and 66.58%, respectively, after 20 min of reaction time using 5 mM of H₂O₂ concentration. Modified generalized kinetic model was developed for TOC removal of dye degradation onto MSIO-NPs, to account for oxidizable compounds, non-oxidizable compounds, and intermediate organic compounds. The intermediate products formed during degradation of NBS dye were detected by LC–MS experiment and ten fragments were identified based on mass to charge ratio (m/z). The mechanistic pathway for degradation of NBS dye onto MSIO-NPs has been proposed.     

Synthesis, antiamoebic activity and thermal study of copper complexes of 1-formyl-2-pyrazolines

Copper complexes of 1-formyl-2-pyrazolines were prepared by the reaction of 1-formyl-2-pyrazolines with copper chloride and nitrate with methanol. The structures of copper complexes 1a–3a have been established by elemental analysis, FT-IR, UV and thermogravimetric analysis. These compounds were tested against HM1:IMSS strain of Entamoeba histolytica by the microdilution method. Complexes 2a and 3a are more active than other complexes.     

QSAR and docking studies on chalcone derivatives for antitubercular activity against M. tuberculosis H37Rv

In our prior studies, we reported some known antitubercular drugs (rifampicin and streptomycin) and newly synthesized chalcone derivatives (16–26) tested in vitro against Mycobacterium tuberculosis H₃₇Rv strain. Most of the tested compounds were efficient antimycobacterial agents showing minimum inhibitory concentration values ranging from 3.5 to 30 µg mL⁻¹. In the present work, a quantitative structure–activity relationship (QSAR) study has been performed on these active chalcone derivatives to correlate their chemical structures with their observed inhibiting activity against M. tuberculosis. A QSAR model that is able to correlate well the antitubercular activity with the chemical structures of active chalcone derivatives 16, 24, 25a, 25c, and 26 has been developed, which is potentially helpful in the design of novel and more potent antitubercular agents. The r² and rCV² of a newly derived QSAR model were 0.89 and 0.84, respectively. The QSAR study indicates that chemical properties, viz. heat of formation (kcal mol⁻¹), lowest unoccupied molecular orbital energy (eV), and amine, hydroxyl, and methyl groups counts, correlate well with the activity. In silico screening results for oral bioavailability and absorption, distribution, metabolism, excretion, and toxicity compliance showed that compounds 25a, 25c, and 24 were found active similar to rifampicin and streptomycin. The docking study for the exploration of mechanism of action showed high binding affinity of active derivatives. Copyright © 2014 John Wiley & Sons, Ltd.     

Studies on the feasibility of recycled polystyrene doped with NLO active meta‐Nitroaniline for optoelectronics applications

A Guest–Host system based on meta‐Nitroaniline (m‐NA) and recycled polystyrene (RPS) susceptible to generate nonlinear optically (NLO) active property such as second harmonic generation (SHG) has been prepared. Pure, sublimed, optical grade, crystalline m‐NA is used as a guest and RPS from the disposable packaging waste as available utilized as the host polymer. In this paper we report the effect of NLO active m‐NA on the bulk and optical properties of RPS. The purified m‐NA was incorporated from 1–10 wt% in the RPS polymer matrix by conventional solution casting method. Thin, transparent, freestanding films obtained were characterized with optical microscope, scanning electron microscope (SEM), viscosity measurement, and UV–Visible (UV–Vis) spectroscopy for bulk properties evaluation and Nd:YAG laser studies for optoelectronics application such as SHG through frequency doubling. Copyright © 2010 John Wiley & Sons, Ltd.     

<Emphasis Type="Italic">I–V</Emphasis> behavior of transition metal oxides′ nanoparticles confined in ion tracks

Behavior of transition metal oxide (TMO) nanoparticles (Fe₃O₄, NiO, Co₃O₄, and Mn₃O₄) inserted in ion tracks has been studied in the presence of magnetic field. The special structure of ion tracks in dielectric layer on semiconductors is known as TEMPOS—‘Tunable Electronic Materials with Pores in Oxide on Silicon’. TEMPOS structure offers a high surface to volume ratio resulting in fast response time and high sensitivity of sensors fabricated by inserting suitable materials in the ion tracks. We have already reported the behavior of ferrofluids (aqueous and non-aqueous) inserted in the TEMPOS structures and its feasibility as earth’s magnetic field sensor. In continuation to this study, a comparative study between different transition metal oxides inserted in the ion tracks is being presented here with an aim to understand their response in confined geometry. This study shows that Fe₃O₄ (ferrofluid) is the best choice for ion track-based magnetic field sensor as compared to NiO, Co₃O₄, and Mn₃O₄. Its response to magnetic field can be tailored by the dilution of the ferrofluid and annealing.     

CsPb3Bi3Te8 and CsPb4Bi3Te9: low-dimensional compounds and the homologous series CsPbmBi3Te5 + m

Two new thermoelectric materials of quaternary bismuth telluride CsPb3Bi3Te8 and CsPb4Bi3Te9 are reported, which are members of a homologous series featuring anionic slabs [PbmBi3Te5 + m]- (m = 1-4) of monotonically increasing thickness.