Development of a miniature Taylor-Couette extractor column for nuclear solvent extraction

Miniature annular centrifugal contactors are nearly perfect for shielded hot-cell applications during flowsheet evaluation but these contactors require complex maintenance of electrical drive-motors during radioactive experiments. To reduce the number of electrical drives in the shielded cell, an indigenous design of miniature Taylor Couette (TC) mixing based countercurrent differential extraction column has been developed. In this paper, results of mass transfer experiments for an indigenously developed TC column with 30% TBP/aqueous nitric acid solutions are reported. The developed device worked perfectly in counter–current differential mode and demonstrated equivalence to multiple-extraction stages while working with a single electrical drive. The developed TC unit demonstrated operation with a reduced efficiency without flooding even in absence of rotor rotation. This observation is a vital step towards designing of robust contactors, which do not flood during temporary power failure or failure of drive mechanism.     

An extensive review on thermodynamic aspect based solar desalination techniques

Journal of Thermal Analysis and Calorimetry - The shortage of freshwater is becoming a major threat to sustainable environmental development. Water desalination techniques provide solutions for...     

Estimation of 14C in irradiated graphite using CO2 gasification method

To efficiently inhibit the diffusion of radioactive nuclides in soil that were left by nuclear emergency accidents, microwave sintering technology was used in this work to vitrify the simulated strontium contaminated soil. Four kinds of simulated strontium-contaminated soil could be successfully vitrified almost completely within 30 min without any additional components. Sr²⁺ cations are immobilized into aluminosilicate glass network structure. In addition, the solubility of SrSO₄ in different soil is related to the element contents of aluminum and silicon. This work reveals a demonstration that beta-radioactive contaminated soil could be treated by microwave vitrifying.

     

Synthesis,characterization and biological studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes with pyrral-l-histidinate

The Schiff base ligand, pyrral-l-histidinate(L) and its Co(II), Ni(II), Cu(II) and Zn(II) complexes were synthesized and characterized by elemental analysis, mass, molar conductance, IR, electronic, magnetic measurements, EPR, redox properties, thermal studies, XRD and SEM. Conductance measurements indicate that the above complexes are 1:1 electrolytes. IR data show that the ligand is tridentate and the binding sites are azomethine nitrogen, imidazole nitrogen and carboxylato oxygen atoms. Electronic spectral and magnetic measurements indicate tetrahedral geometry for Co(II) and octahedral geometry for Ni(II) and Cu(II) complexes, respectively. The observed anisotropic g values indicate the presence of Cu(II) in a tetragonally distorted octahedral environment. The redox properties of the ligand and its complexes have been investigated by cyclic voltammetry. Thermal decomposition profiles are consistent with the proposed formulations. The powder XRD and SEM studies show that all the complexes are nanocrystalline. The in vitro biological screening effects of the synthesized compounds were tested against the bacterial species, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus; fungal species, Aspergillus niger, Aspergillus flavus and Candida albicans by the disc diffusion method. The results indicate that complexes exhibit more activity than the ligand. The nuclease activity of the ligand and its complexes were assayed on CT DNA using gel electrophoresis in the presence and absence of H₂O₂.     

Distribution functions for subsequences of the van der Corput sequence

For an integer b>1$b>1$ let _(?b(n))n≥0${\left({?}_b\left(n\right)\right)}_{n\ge 0}$ denote the base b$b$ van der Corput sequence in [0,1)$[0,1)$. Answering a question of O. Strauch, C. Aisleitner and M. Hofer showed that the distribution function of _{(?b(n),?b(n+1),…,?b(n+s−1))n≥0}${({?}_b\left(n\right),{?}_b(n+1),\dots ,{?}_b(n+s-1))}_{n\ge 0}$ on [0,1)^s${[0,1)}^s$ exists and is a copula. In this note we show that this phenomenon extends to a broad class of subsequences of the van der Corput sequences.     

Optimal continued fractions and the moving average ergodic theorem

We use the moving average ergodic theorem of A. Bellow, R. Jones and J. Rosenblatt to derive various results in metric number theory primarily concerning moving averages of various sequences attached to the optimal continued fraction expansion of a real number.