Measurement of dispersion numbers for 36 and 100% tri-isoamyl phosphate solvents equilibrated with aqueous nitric acid solutions

The cross sections for the ¹¹⁸Sn (n, α)¹¹⁵Cd, ¹²⁰Sn (n, α)^117gCd and ¹²⁰Sn (n, α)^117mCd reactions have been measured in the neutron energy range of 13.5–14.6 MeV using the activation technique and a coaxial HPGe γ-ray detector. The fast neutrons were produced by the T (d, n) ⁴He reaction. The neutron energies in the measurements were determined by cross section ratios for ⁹³Nb(n,2n)^92mNb and ⁹⁰Zr(n, 2n)^89m+gZr reactions. The results of present work were discussed and compared with theoretical calculation data, measurement results found in the literature and with the comprehensive evaluation data in ENDF/B-VII.0, CENDL-3.1, JENDL-4.0 libraries.     

Direct dissolution of intact UO<Subscript>2</Subscript> pellet and in situ extraction by organic solutions of TBP-HNO<Subscript>3</Subscript> at atmospheric pressure: role of solvate composition

Recently authors demonstrated direct dissolution of g-level PHWR UO₂ fuel pellet fragments and in situ extraction by TBP-HNO₃ and TiAP-HNO₃ solutions at atmospheric pressures. Extending the work, similar studies were performed on intact unirradiated PHWR UO₂ fuel pellets (~15 g U) with varying compositions of organic solvate of tri-n-butyl phosphate (TBP). It was observed that extent of dissolution was a strong function of organic solution composition TBP·(HNO₃) _x (H₂O) _y . Complete dissolution of intact UO₂ pellet in a reasonable time was observed only in case of a particular solvate composition.     

Thermal stability of UNEX/HCCD-PEG diluent FS-13

Phenyl trifluoromethyl sulfone (FS-13) is an inert diluent used in HCCD/PEG process for isolation and recovery of cesium and strontium from highly radioactive raffinate waste. There is no experimental data available in open literature describing pressurization due to the thermal decomposition of FS-13 at elevated temperatures. Experiments were conducted for determination of flash point and heating of FS-13 under pressurized closed-vent conditions in an adiabatic calorimeter. During adiabatic experiments, negligible pressurization was observed.     

Effect of terminal N-substitution in 2-oxo-1,2-dihydroquinoline-3-carbaldehyde thiosemicarbazones on the mode of coordination, structure, interaction with protein, radical scavenging and cytotoxic activity of copper(II) complexes

Four 2-oxo-1,2-dihydroquinoline-3-carbaldehyde N-substituted thiosemicarbazone ligands (H(2)-OQtsc-R, where R = H, Me, Et or Ph) and their corresponding new copper(II) complexes [CuCl(2)(H(2)-OQtsc-H)]·2H(2)O (1), [CuCl(2)(H(2)-OQtsc-Me)]·2H(2)O (2), [CuCl(2)(H(2)-OQtsc-Et)(CH(3)OH)]Cl (3) and [CuCl(H-OQtsc-Ph)]·CH(3)OH (4) have been synthesized in order to correlate the effect of terminal N-substitution on coordination behaviour, structure and biological activity. Single crystal X-ray diffraction studies revealed that the complexes 1, 2 and 3 have square pyramidal geometry around the central metal ion. In the complexes 1 and 2, the copper ion is coordinated by the ligand with ONS donor atoms, one chloride ion in apical position and the other chloride in the basal plane. Complex 3 consists of [CuCl(2)(H(2)-OQtsc-Et)(CH(3)OH)](+) cation and a chloride as counter ion. The copper ion is coordinated by the ligand with ONS donor atoms and by one chloride ion in the basal plane. One methanol molecule is bonded through its neutral oxygen in the apical position. Complex 4 is square planar with the ligand coordinating through uni-negative tridentate ONS(-) and by one chloride ion in the basal plane. The binding of complexes with lysozyme protein was carried out by fluorescence spectroscopy. Investigations of antioxidation properties showed that all the copper(II) complexes have strong radical scavenging properties. The cytotoxicity of the complexes 3 and 4 against NIH 3T3 and HeLa cell lines showed that synergy between the metal and ligands results in a significant enhancement in the cell death with IC(50) of ~10-40 μM. A size dependence of substitution at terminal N in the thiosemicarbazones on the biological activities of the complexes has been observed.     

Green synthesis of biogenic metal nanoparticles by terrestrial and aquatic phototrophic and heterotrophic eukaryotes and biocompatible agents

The size, shape and controlled dispersity of nanoparticles play a vital role in determining the physical, chemical, optical and electronic properties attributing its applications in environmental, biotechnological and biomedical fields. Various physical and chemical processes have been exploited in the synthesis of several inorganic metal nanoparticles by wet and dry approaches viz., ultraviolet irradiation, aerosol technologies, lithography, laser ablation, ultrasonic fields, and photochemical reduction techniques. However, these methodologies remain expensive and involve the use of hazardous chemicals. Therefore, there is a growing concern for the development of alternative environment friendly and sustainable methods. Increasing awareness towards green chemistry and biological processes has led to a necessity to develop simple, cost-effective and eco-friendly procedures. Phototrophic eukaryotes such as plants, algae, and diatoms and heterotrophic human cell lines and some biocompatible agents have been reported to synthesize greener nanoparticles like cobalt, copper, silver, gold, bimetallic alloys, silica, palladium, platinum, iridium, magnetite and quantum dots. Owing to the diversity and sustainability, the use of phototrophic and heterotrophic eukaryotes and biocompatible agents for the synthesis of nanomaterials is yet to be fully explored. This review describes the recent advancements in the green synthesis and applications of metal nanoparticles by plants, aquatic autotrophs, human cell lines, biocompatible agents and biomolecules.     

Simulation of beam plastic forming with variable bending moments

A versatile generic elastic/plastic moment/curvature equation is used to simulate beam deflections. Solutions are obtained numerically and used to investigate whether forming equations based on the assumption of pure bending can be extended in a rational way to more complicated loadings. It is concluded that the answer is affirmative, with only knowledge of the elastic/plastic behavior associated with pure bending and the elastic behavior associated with the actual loading being needed to make the extension.     

Convergence analysis of virtual element methods for semilinear parabolic problems on polygonal meshes

In this article, we discuss and analyze new conforming virtual element methods (VEMs) for the approximation of semilinear parabolic problems on convex polygonal meshes in two spatial dimension. The spatial discretization is based on polynomial and suitable nonpolynomial functions, and a Euler backward scheme is employed for time discretization. The discrete formulation of both the proposed schemes—semidiscrete and fully discrete (with time discretization) is discussed in detail, and the unique solvability of the resulted schemes is discussed. A priori error estimates for the proposed schemes (semidiscrete and fully discrete) in H¹‐ and L²‐norms are derived under the assumption that the source term f is Lipschitz continuous. Some numerical experiments are conducted to illustrate the performance of the proposed scheme and to confirm the theoretical convergence rates.     

Electrical characterization of PVA-based nanocomposite electrolyte nanofibre mats doped with a multiwalled carbon nanotube

An attempt has been made to prepare and characterise ammonium thiocyanate (NH₄SCN) salt and a multiwall carbon nanotube (MWNT)-doped polyvinyl alcohol-based nanofibre mats using an electrospinning process. The X-ray diffraction result shows an improvement in the amorphous nature of composite electrolyte fibre mats with increasing concentrations of the MWNT filler. The DSC behaviour of these nanofibre mat exhibits better thermal response upon dispersal of the filler. Composite electrolyte nanofibre mat doped with 6 wt% MWNT shows optimum conductivity, viz., 5.8?×?10^?4 Scm^?1. The temperature dependence of the bulk electrical conductivity displays a combination of Arrhenius and Vogel–Tammam–Fulcher nature. Dielectric loss studies have also been used to understand the conduction process in the system. Jonscher power law seems to be obeyed during ac conductivity measurements of the fibre mats.     

Mn site substitution of La0.67Ca0.33MnO3 with closed shell ions: Effect on magnetic transition temperature

Mn site is substituted with closed shell ions (Al, Ga, Ti, Zr and a certain combination of Zr and Al) and also with Fe and Ru ions carrying the magnetic moment (S=5/2 and 2 respectively) at a fixed concentration of 5 at %. Substitution did not change either the crystal symmetry or the oxygen stoichiometry. All substituents were found to suppress both the metal-insulator and ferromagnetic transition temperatures (T _p(ρ) and T _C, respectively) to varied extents. Two main contributions identified for the suppression are the lattice disorder arising due to difference in the ionic radii between the substituent (r _M) and the Mn³⁺ ion (r _Mn ³⁺) and in the case of the substituents carrying a magnetic moment, the type of magnetic coupling between the substituent and that of the neighboring Mn ion.