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The reaction between Ta(OEt)(sub 5) and 1,1,3,3-tetramethyl-1,3-disiloxanediol, (HOSiMe2OSiMe2OH), produces new siloxy complexes in which the dimeric nature of Ta(OEt)(sub 5) is maintained with both bridging ethoxide and disiloxanediolato bridges. The structural and spectroscopic characterization, catalytic properties and thermal transformations of these new complexes are discussed.

The rare-earth binding properties of two hydrophobic carbamoylmethylphosphine oxide (CMPO) ligands, the normal bidentate variety, a tridentate extractant and tributyl phosphate are evaluated. The results show that as the ionic radius of the lanthanide ion decreases, a pair of the carbamoylmethylphosphine ligands is able to completely solvate a bound metal ion thereby weakening the nitrate-metal interaction.

The series of compounds (o-[CH.sub.3][SC.sub.6][H.sub.4])[CH.sub.2] [EPh.sub.3] (E = Si (1), Ge (2), Sn (3), and Pb (4)) have been synthesized and characterized by NMR spectroscopy and by single crystal X-ray diffraction. Compounds 1 and 2 are isostructural with a triclinic crystal system and P-1 space group; however, morphotropic steps occur between Ge and Sn, and Sn and Pb. While the E-S distances in 1 and 2 are 3.985 and 3.974 [Angstrom], respectively, ~100% of the sum of the respective van der Waals (vdW) radii, there is a notable distortion from tetrahedral geometry about E. Compound 3 is also triclinic with P-1 symmetry, but has two molecules in the unit cell that demonstrate a distorted tetrahedral geometry and intramolecular Sn-S distances of 3.699 and 3.829 [Angstrom], 88% and 91% of the sum of the vdW radii. Compound 4 has a Pb-S distance of 3.953 [Angstrom] (91% of E vdW radii). The structure of the Grignard coupling product [[o-(SC[H.sub.3])[C.sub.6][H.sub.6]C[H.sub.2]].sub.2] is also reported. Key words: intramolecular self-assembly, silicon, germanium, tin, lead, sulfur.

This article critically analyses and evaluates the research study on the two-phase cascade flow in a flume model reported earlier in the journal by M.R. Chamani and N. Rajaratnam. The analysis covers a wide range of cognate topics including skimming flow characteristics, free-surface aeration process, air concentration distribution, and energy dissipation.

Effect of partition resistance and surface radiation on natural convection heat transfer are discussed based on experimentation using a partitioned enclosure and a differential interferometer. Focus was on effect of surface emissivity of walls and partition on the overall heat transfer in the enclosure. Correlations valid for the laminar range are offered.

Polypyrrole (PPy)–molybdenum trioxide (MoO3) is a polymer‐metal oxide composite (99.9% pure) obtained when two are mixed mechanically with different wt% in acetone medium to obtain different PPy–MoO3 composite materials. The thick films of pure PPy and PPy–MoO3 polymer‐metal oxide composite are prepared by screen printing technique. The prepared mixed composite polymer‐metal oxide materials are calcinated at 800°C for 8 h in air. The thick films are investigated for structural, electrical, and morphological properties. The surface morphology of the thick films is studied by scanning electron microscope (SEM) which shows that the films are granular and porous in nature. The gas responses of pure PPy and PPy–MoO3 polymer‐metal oxide composite thick films are studied for different gases such as ammonia gas (NH3) and ethanol gas at room temperature. The pure PPy thick film shows the poor response to ammonia and ethanol gas, while the thick film 40PPy–60MoO3 gave good responses to ethanol gas (50 ppm) at room temperature. The gas selectivity, sensitivity, stability, gas response, and recovery time of the sensor are measured and presented. [ABSTRACT FROM AUTHOR]

Tm3+‐doped La2O3 phosphors with different doping concentration are prepared by co‐precipitation method. The prepared phosphor is characterized by X‐ray powder diffraction (XRD), SEM, Fourier transform infrared (FT‐IR) spectroscopy, and photoluminescence (PL) techniques. The XRD analysis confirms the formation of La2O3. PL measurement shows that the phosphor exhibit characteristic Tm3+ bright blue emission attributed to transition from 1D2 → 3F4 of Tm3+ ions, at 363 nm excitation. The Commission International de I'Eclairage (CIE) chromaticity color coordinates of prepared phosphor is calculated and presented. The excitation peak located at 363 nm matches with the emission wavelength of near UV‐LED chip, this indicates that the prepared phosphor is a promising blue light‐emitting candidate for eco‐friendly solid state lighting (W‐LED) application. [ABSTRACT FROM AUTHOR]

In this study, the structural and magnetic properties of Co0.9Zn0.1Fe2O4 ferrite nanoparticles are prepared by using chemical co‐precipitation method and characterized with X‐ray diffraction (XRD) and vibrating sample magnetometer (VSM). The structural results show that the particles have a formation of single‐phase cubic spinel structure and that the particles have a nano scale, with a clear agglomeration between the particles. The crystallite size of the sample is found 6.21 nm by using Scherer's formula, while the lattice parameters is 8.38 Å. The VSM study shows the saturation magnetization (Ms) 30.18 emu g‐1 and coercivity (Hc) 500 Oe along with hysteresis and to calculate the Ms values the Law of approach to saturation is used. The dried sample of ferrite is characterized with an FTIR‐spectrophotometer in wave number range of 4200–800 cm−1. [ABSTRACT FROM AUTHOR]