Recovery of molybdenum by solvent extraction from simulated high level liquid waste

Journal of Radioanalytical and Nuclear Chemistry - In this study, simple and a rapid solvent extraction method is investigated to recover Mo(VI) from simulated HLLW. The (NH4)6Mo7O24·4H2O...     

Synthesis,characterization and antitumor activities of some novel thiazinones and thiosemicarbazones derivatives

Abstract

Two series of thiazinone and thiosemicarbazone derivatives (1-12) were synthesized using 2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-ones (ABNs) and 3–alkyl–2,6–diarylpiperidin–4–ones as the starting materials. The structures of newly synthesized compounds were established on the basis of FT–IR, NMR spectroscopy and mass spectrometry. From the spectroscopic data, we identified that the cyclization reaction of thioamide with dialkyl acetylenedicarboxylate selectively gives six membered methyl 2-(2-(2,4-disubstituted-3-azabicyclo[3.3.1]nonan-9-ylidene)hydrazinyl)-4-oxo-4H-1,3-thiazine-6-carboxylates (1-6). In order to investigate the antitumor activities of the synthesized compounds, in vitro cytotoxicity studies were carried out using human prostate cancer cell lines. Tested compounds showed good/moderate activities against cancer cell lines and further investigation carried out by live/dead assay.     

Synthesis and Characterization of ZnO Nanoparticles and Their Natural Rubber Composites

Abstract

Nanoparticles of zinc oxide were synthesized by a solution combustion method. The average size of these particles was analyzed by using X-ray diffraction. Composites of natural rubber and the ZnO nanoparticles were prepared by a latex blending method. The matrix phase was cured by using the crosslinking agent, pentane-1,5-diylidenediamine. Effects of crosslinking and incorporation of nanoparticles on the tensile and solvent transport properties of the natural rubber were studied in detail. The nature of the dispersion of the nanoparticles was analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). It was observed from the tensile studies that the addition of the curing agent and the ZnO nanoparticles increased the stability considerably. Incorporation of the nanoparticles also considerably increased the solvent resistance of the cured natural rubber. We suggest the addition of ZnO nanoparticles at a low loading level provided better properties compared to other reinforcements, such as carbon black and nano-clay.     

Simple algebraic and semialgebraic groups over real closed fields

We continue the investigation of infinite, definably simple groups which are definable in o-minimal structures. In Definably simple groups in o-minimal structures, we showed that every such group is a semialgebraic group over a real closed field. Our main result here, stated in a model theoretic language, is that every such group is either bi-interpretable with an algebraically closed field of characteristic zero (when the group is stable) or with a real closed field (when the group is unstable). It follows that every abstract isomorphism between two unstable groups as above is a composition of a semialgebraic map with a field isomorphism. We discuss connections to theorems of Freudenthal, Borel-Tits and Weisfeiler on automorphisms of real Lie groups and simple algebraic groups over real closed fields.

     

Recent studies in heavy ion induced fission reactions

Nuclear fission process involves large scale shape changes of the nucleus, while it evolves from a nearly spherical configuration to two separated fission fragments. The dynamics of these shape changes in the nuclear many body system is governed by a strong interplay of the collective and single particle degrees of freedom. With the availability of heavy ion accelerators, there has been an impetus to study the nuclear dynamics through the investigations of nucleus-nucleus collisions involving fusion and fission process. From the various investigations carried out in the past years, it is now well recognized that there is large scale damping of collective modes in heavy ion induced fission reactions, which in other words implies that nuclear motion is highly viscous. In recent years, there have been many experimental observations in heavy ion induced fission reactions at medium bombarding energies, which suggest possible occurrence of various non-equilibrium modes of fission such as quasi-fission, fast fission and pre-equilibrium fission, where some of the internal degrees of freedom of the nucleus is not fully equilibrated. We have carried out extensive investigations on the fission fragment angular distributions at near barrier bombarding energies using heavy fissile targets. The measured fragment anisotropies when compared with the standard saddle point model (SSPM) calculations show that for projectile-target systems having zero or low ground state spins, the angular anisotropy exhibits a peak-like behaviour at the sub barrier energies, which cannot be explained by the SSPM calculations. For projectiles or targets with large ground state spins, the anomalous peaking gets washed out due to smearing of the K-distribution by the intrinsic entrance channel spins. Recently studies have been carried out on the spin distributions of fission fragments through the gamma ray multiplicity measurements. The fission fragments acquire spin mainly from two sources: (i) due to rigid rotation of the nascent fragments at scission and (ii) due to statistical excitation of the spin bearing collective modes in the fissioning nucleus. One of the collective modes — the tilting mode depends on the K quantum number and is responsible for the emission angle dependence of fragment spin. In our studies, we have shown conclusively that the collective statistical spin modes get strongly suppressed for high K values corresponding to large rotational frequencies along the fission axis. These results bring out the importance of the dynamical effects in the heavy ion induced fusion-fission reactions. The present article will review the work carried out on the above aspects in heavy ion fission reactions as well as on the fission time scales, and some of the recent studies on the mass-energy correlations of fission fragments at near-barrier bombarding energies.     

First order difference system- existence and uniqueness

In this paper, the general solution of the homogeneous matrix difference system is constructed in terms of two fundamental matrix solutions. The general solution of the inhomogeneous matrix difference system is established by the variation of parameters formula. A unique solution of the two-point boundary value problem associated with the matrix difference system is constructed by applying the QR-algorithm and the Bartels-Stewart algorithm.

     

Ultracompact directional couplers realized in InP by utilizing feature size dependent etching

We present the design, fabrication, and measurement of an ultracompact directional coupler in InP/InGaAsP/InP. By utilizing the lag effect in the dry etching process, in one etch step, deeply etched asymmetric waveguides with a shallow groove in between are fabricated. This special property enhances the coupling efficiency for the directional coupler and thus makes the device ultracompact. We demonstrate directional couplers as short as 55 microm, which is only 1/30th the length of the conventional design.     

Characterizations of the uniform distribution via sample spacings and nonlinear transformations

We prove that an absolutely continuous probability distribution with compact support is uniformly distributed if and only if the mean sample spacings resulting from a random sample of size N are all equal for every integer N. We also present a related characterization of uniformity using nonlinear transformations. We discuss potential applications of these results to hypothesis testing and to testing the effectiveness of different random number generators.