Comparative study of the extraction of Te(IV) from various aqueous solutions using different organic diluents and solvents

The extraction of Te(IV) from aqueous solutions containing various ligands was studied using various inert organic diluents and other solvents. The extraction was carried out from solutions of various mineral (HCl, HBr, HI, HNO₃) and organic (citric, oxalic) acids of various concentrations. The organic phase was an inert diluent (cyclohexane, CCl₄, chloroform, benzene, p-xylene, toluene, nitrobenzene) or a solution of 20 vol % Aliquat-336, 20 vol % trioctylamine, or 30 vol % TBP in p-xylene. A correlation between the distribution of Te(IV) and some physicochemical properties of the diluents and the possibility of extraction separation radioactive Te isotopes and their daughters, i.e., radioactive I isotopes, were examined. In most cases, the Te(IV) distribution ratio decreases in the order nitrobenzene > CHCl₃ > CCl₄ > p-xylene > benzene > toluene > cyclohexane. Published in Russian in Radiokhimiya, 2007, Vol. 49, No. 4, pp. 353–358. The text was submitted by the authors in English. An erratum to this article is available at .     

Roll manufacturing of flexible microfluidic devices in thin PMMA and COC foils by embossing and lamination

Microfluidics on foil is gaining momentum due to a number of advantages of employing thin films combined with the capability of cost-effective high-volume manufacturing of devices. In this work, ultra-thin, flexible Y-microreactors with microchannels of 100 μm width and 30 μm depth were fabricated in thermoplastic polymer foils. The fluidic pattern was hot roll embossed in 125 μm thick poly-methyl-methacrylate (PMMA) and 130 μm thick cyclic-olefin-copolymer (COC) films using a dry-etched microstructured silicon wafer as a flat embossing tool in a laminator. The sealing of the channels was performed with two different techniques, one based on lamination of SU8 dry film resist (DFR) and the other one based on spin-coated poly-dimethylsiloxane (PDMS). Testing of the interconnected microreactor was carried out using two dye colorant solutions to demonstrate mixing.     

Flux measurements for a DD neutron generator using neutron activation analysis

The fast and maximum thermal neutron fluxes from the DD-109 neutron generator at the University of Sharjah were experimentally measured by the activation technique using different neutron reactions. The thermal and fast neutron fluxes were found to be 2.960 × 10~6 and6.186 × 10~7 n/cm~2 s, respectively. This was done to verify the modeling results for the optimum moderator thickness needed to maximize the thermal neutron flux. The optimum moderator thickness was found to be between 3.5 and4 cm. The present data were compared with the detailed MCNP model-based calculation performed in earlier work to simulate the generator.     

New Side-Looking Rogowski Coil Sensor for Measuring Large-Magnitude Fast Impulse Currents

This paper presents a new design of a side-looking “flat spiral” self-integrating Rogowski coil that is wound by twin coaxial cable with individual sheath. The coil is tested with different impulse current waveforms up to 7 kA peak value to improve its performance. The coil design is optimized to achieve bandwidth and sensitivity up to 7.854 MHz and 3.623 V/kA, respectively. The coil is calibrated versus two commercial impulse-current measurement devices at different coil-to-wire separations, coil inclination angles, and impulse current waveforms. Distortion of the coil output voltage waveform is examined by using the lumped-element model to optimize the connections of the four cable winding sheaths and the coil termination resistance. Finally, the coil frequency response is investigated to optimize the coil design parameters and achieve the desired bandwidth (large low-frequency time constant), high rate of rise, no overshoot, very small droop, high rate of fall, and no backswing.     

Tape-wound Rogowski coil for measuring large-magnitude pulsed currents

This paper presents design, calibration and testing of a new tape-wound Rogowski coil for measuring large-magnitude pulsed currents. The performance of the coil is tested by different impulse current waveforms up to 9 kA peak value. The coil is calibrated versus two commercial impulse-current transformers with different impulse current waveforms. The coil design is optimized to work in the differentiating mode and achieve useful bandwidth and sensitivity up to 1 MHz and 102 mV/kA, respectively. Waveform distortion of the coil output voltage is examined by using the lumped-element model to optimize the parameters of the external passive integrator. It is desired to optimize the integrator parameters and achieve the desired bandwidth without having droop and backswing. To do so, the coil frequency response is investigated by making fast Fourier transform (FFT) of the impulse current waveforms and PSPICE simulation of the lumped parameter equivalent circuit of Rogowski coil and the external integrator. Finally, it is found that the PSPICE calculated sensitivity for the optimized integrator parameters deviates from the corresponding measured one by a percentage relative error of–0.05%.     

The effect of the decline in oil revenue on the import patterns of the members of the gulf cooperation council

This paper examines the impact of the fluctuations in oil revenue on the import patterns of the GCC countries. The study is a disaggregated analysis of the relationship between imports of various commodity groups, using two-digit SIT classifications and per capita income in each of the six members of the Gulf Cooperation Council (GCC). The research shows that the reduction in oil revenue since late 1982 has completely upset the import-income relationship which was developed during the boom years, 1974–1981.     

Synthesis and Properties of Synthetic Egyptian Corncob-Phenol Formaldehyde Cationic Exchanger

Studies have been carried out on the synthesis, composition, stability, and ion-exchange properties of cationic resins from poly-condensation of Egyptian corncobs (as a source of inexpensive and renewable material) with phenol in the presence of parafonnaldehyde as a crosslinking agent. These exchangers are stable in water, organic solvents, thermal treatment and mineral acids (1 M). The samples, having a cation-exchange capacity up to 3.22 mEq g^?1 of dry resin, are being introduced as a new cationic exchanger. The cationic exchanger shows a limited affinity for the binary separation of some divalent cations.     

Assessment of nuclear energy sustainability index using fuzzy logic

Nuclear energy is increasingly perceived as an attractive mature energy generation technology that can deliver an answer to the worldwide increasing energy demand while respecting environmental concerns as well as contributing to a reduced dependence on fossil fuel. Advancing nuclear energy deployment demands an assessment of nuclear energy with respect to all sustainability dimensions.In this paper, the nuclear energy, whose sustainability will be assessed, is governed by the dynamics of three subsystems: environmental, economic, and sociopolitical. The overall sustainability is then a non-linear function of the individual sustainabilities. Each subsystem is evaluated by means of many components (pressure, status, and response). The combination of each group of indicators by means of fuzzy logic provides a measurement of sustainability for each subsystem.     

Synthesis of a new sulphonated cation exchange resin and its application in catalysed hydrolysis of esters

Samples of an acidic cation exchanger have been prepared by sulphonation of acrylonitrile butadiene styrene copolymer previously cross-linked with phenol-formaldehyde resin. The samples having a cation exchange capacity of 3.48 meqg^–1, are being introduced as new catalysts in the hydrolysis of ethyl acetate. The synthesized cation exchanger shows good thermal and chemical stability. Hydrolysis rate constants (K _r values) for the catalysed reaction have been determined. The efficiency of the resin catalyst,q, is shown to be a function of resin concentration.