Fatty amides synthesized from vegetable oil as extractant of molybdenum(VI)

In this study, fatty amides (FAs) synthesized from palm olein were used to extract and separate Mo(VI) from acidic media. Effects of various parameters upon the separation of Mo(VI) from Co(II), Ni(II), Al(III) and Mn(II), including extractant concentration, metal ion concentration, contact time, diluent, and acidity, were investigated. It was found that Mo(VI) was successfully separated from the above commonly associated metal ions by stripping from the loaded organic phase. Different acidic and alkaline solutions were used. Ammonium hydroxide solution was an optimal. Extraction of Mo(VI) into the organic phase involved the formation of 1:3 complexes. This work presents the development of a low-cost and environmentally friendly extractant to recycle and recover molybdenum.     

A facile and green synthetic approach toward fabrication of starch-stabilized magnetite nanoparticles

A facile and green synthetic approach for fabrication of starch-stabilized magnetite nanoparticles was implemented at moderate temperature. This synthesis involved the use of iron salts, potato starch,sodium hydroxide and deionized water as iron precursors, stabilizer, reducing agent and solvent respectively. The nanoparticles(NPs) were characterized by UV-vis, PXRD, HR-TEM, FESEM, EDX, VSM and FT-IR spectroscopy. The ultrasonic assisted co-precipitation technique provides well formation of highly distributed starch/Fe_3O_4-NPs. Based on UV–vis analysis, the sample showed the characteristic of surface plasmon resonance in the presence of Fe_3O_4-NPs. The PXRD pattern depicted the characteristic of the cubic lattice structure of Fe_3O_4-NPs. HR-TEM analysis showed the good dispersion of NPs with a mean diameter and standard deviation of 10.68 4.207 nm. The d spacing measured from the lattice images were found to be around 0.30 nm and 0.52 nm attributed to the Fe3O4 and starch, respectively. FESEM analysis confirmed the formation of spherical starch/Fe_3O_4-NPs with the emission of elements of C, O and Fe by EDX analysis. The magnetic properties illustrated by VSM analysis indicated that the as synthesized sample has a saturation magnetization and coercivity of 5.30 emu/g and 22.898 G respectively.Additionally, the FTIR analysis confirmed the binding of starch with Fe_3O_4-NPs. This method was cost effective, facile and eco-friendly alternative for preparation of NPs.     

Fully integrated PDMS/SU-8/quartz microfluidic chip with a novel macroporous poly dimethylsiloxane (PDMS) membrane for isoelectric focusing of proteins using whole-channel imaging detection

A fully integrated polydimethylsiloxane (PDMS)/modified PDMS membrane/SU-8/quartz hybrid chip was developed for protein separation using isoelectric focusing (IEF) mechanism coupled with whole-channel imaging detection (WCID) method. This microfluidic chip integrates three components into one single chip: (i) modified PDMS membranes for separating electrolytes in the reservoirs from the sample in the microchannel and thus reducing pressure disturbance, (ii) SU-8 optical slit to block UV light (below 300?nm) outside the channel aiming to increase detection sensitivity, and (iii) injection and discharge capillaries for continuous operation. Integration of all these components on a single chip is challenging because it requires fabrication techniques for perfect bonding between different materials and is prone to leakage and blockage. This study has addressed all the challenges and presented a fully integrated chip, which is more robust with higher sensitivity than the previously developed IEF chips. This chip was tested by performing protein and pI marker separation. The separation results obtained in this chip were compared with that obtained in commercial cartridges. Side-by-side comparison validated the developed chip and fabrication techniques.     

Extraction of molybdenum(VI) from hydrochloric acid solution by N,N’-carbonyl difatty amides

Hydrofluoric acid has been used as a stripping agent for molybdenum(VI) using a mixture of N,N’-carbonyl difatty amides (CDFAs) synthesized from palm oil as a extractant. The CDFAs was characterized by Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance technique. In the extraction step, the effects of parameters, such as type of diluent, hydrochloric acid, metal concentration, and temperature, have been studied. The effects of various stripping agents on stripping efficiency have also been investigated. This work presents the development of a low-cost and environmentally friendly extractant to recover molybdenum.     

Simple Zeros of the Riemann Zeta-Function

Assuming the Riemann Hypothesis, Montgomery showed by meansof his pair correlation method that at least two-thirds of thezeros of Riemann's zeta-function are simple. Later he and Taylorimproved this to 67.25 percent and, more recently, Cheer andGoldston increased the percentage to 67.2753. Here we proveby a new method that if the Riemann and Generalized LindelöofHypotheses hold, then at least 70.3704 percent of the zerosare simple and at least 84.5679 percent are distinct. Our methoduses mean value estimates for various functions defined by Dirichletseries sampled at the zeros of the Riemann zeta-function. 1991Mathematics Subject Classification: 11M26.     

Quantum Zeno and anti-Zeno paradoxes

Continuous observation of a time independent projection operator is known to prevent change of state (the quantum Zeno paradox). We discuss the recent result that generic continuous measurement of time dependent projection operators will in fact ensure change of state: an anti-Zeno paradox.