Recovery of cobalt sulfate from spent lithium ion batteries by reductive leaching and solvent extraction with Cyanex 272

Cobalt sulfate was recovered from crushed and screened prismatic type spent lithium ion batteries (LIBs) containing 5-20% Co, 5-7% Li, 5-10% Ni, 15% organic chemicals, and 7% plastics together with Cu, Al, Fe, and Mn. Cobalt was reductively leached from the - 16 mesh fraction in 1 h by stirring with 2 M H2SO4 and 6 vol.% H2O2, at 60 °C and 300 rpm using a solid/liquid ratio of 100 g/L to give a cobalt concentration of 28 g/L, corresponding to a leaching efficiency of > 99%. Metal ion impurities such as copper, iron, and aluminium were precipitated as hydroxides from solution by adjusting pH to 6.5. Cobalt was then selectively extracted from the purified aqueous phase by equilibrating with 50% saponified 0.4 M Cyanex 272 at an equilibrium pH ∼ 6. The McCabe-Thiele plot predicted 99.9% cobalt extraction in a 2 stage counter-current operation with A/O ratio of 1/2. Separation factors for the extraction of Co/Li and Co/Ni at pH 6 were close to 750. The stripping of the loaded organic phase with 2 M H2SO4 produced a solution of 96 g/L Co from which pure pigment grade cobalt sulfate could be recovered by evaporation/recrystallisation. Overall, 92% cobalt could be recovered from the spent lithium ion batteries

Cholesterol granuloma in the wall of a mandibular dentigerous cyst: a rare case report

Cholesterol granuloma is an inflammatory reaction to cholesterol crystals deposition. It may develop in a variety of sites including the middle ear, mastoid process or even paranasal sinuses. Very few cases of cholesterol granuloma occurring in the jaws were reported. This report presents a rare case of cholesterol granuloma that developed in the wall of a large mandibular dentigerous cyst. The condition was treated with hemimandibulectomy followed by reconstruction with a free fibular flap

Is bi-maximal mixing compatible with the large angle MSW solution of the solar neutrino problem?

It is shown that the large angle MSW solution of the solar neutrino problem with a bi-maximal neutrino mixing matrix implies an energy-independent suppression of the solar nu_e flux. The present solar neutrino data exclude this solution of the solar neutrino problem at 99.6% CL.Comment: 6 pages. No figure

Spin Fluctuation and Persistent Current in a Mesoscopic Ring Coupled to a Quantum Dot

We investigate the persistent current influenced by the spin fluctuations in a mesoscopic ring weakly coupled to a quantum dot. It is shown that the Kondo effect gives rise to some unusual features of the persistent current in the limit where the charge transfer between two subsystems is suppressed. Various aspects of the crossover from a delocalized to a localized dot limit are discussed in relation with the effect of the coherent response of the Kondo cloud to the Aharonov-Bohm flux.Comment: 4 pages, 2 figure

Human monoclonal antibodies that neutralize anthrax toxin by inhibiting heptamer assembly

A panel of human anti-anthrax protective antigen IgG1 monoclonal antibodies were evaluated to determine the mechanism of toxin neutralization. AVP-22G12, AVP-1C6 and AVP-21D9 bound to the protective antigen with picomolar affinities to distinct non-overlapping linear epitopes. Two of the antibodies neutralized the anthrax toxin by completely inhibiting the protective antigen oligomer assembly process in vitro

Development of wirelessly-powered, extracranial brain activator (ECBA) in a large animal model for the future non-invasive human neuromodulation

As transcranial electrical stimulation (tES) is an emerging and promising technique for neuromodulation, we developed a novel device; wirelessly-powered, extracranial brain activator (ECBA), which is mounted subcutaneously, and its neuromodulation effect was investigated. The oscillatory changes in electrocorticography (EcoG) were analyzed from two types of stimulation. Two weeks prior to the recording experiment, we underwent surgery for implantation of subdural strips and ECBA module over centroparietal regions of anesthetized beagles. Low-frequency stimulation (LFS) and subsequent high-frequency stimulation (HFS) protocols (600 pulses respectively) were applied. Then, the power changes before and after each stimulation in five different bands were compared. A significantly larger voltage difference with subcutaneous than transcutaneous stimulation measured at EcoG channels indicated a substantial current attenuation between the skin and skull. Compared with the baseline, all subjects showed consistently decreased delta power and increased gamma power after HFS. LFS also induced a similar, but opposite, pattern of power change in four beagles. The results from this study indicate that LFS and HFS with our novel ECBA can consistently and effectively modulate neural activity of the cortex, inducing neural inhibition and facilitation functions, respectively. Future studies are necessary to further ensuring a consistent efficacy and long-term safety.11Ysciescopu

Equations for filling factor estimation in opal matrix

We consider two equations for the filling factor estimation of infiltrated zinc oxide (ZnO) in silica (SiO_2) opal and gallium nitride in ZnO opal. The first equation is based on the effective medium approximation, while the second one - on Maxwell-Garnett approximation. The comparison between two filling factors shows that both equations can be equally used for the estimation of the quantity of infiltrated nanocrystals inside opal matrix.Comment: 14 pages, 7 figures, 1 table. Addendum to the article: http://arxiv.org/abs/physics/050815

Magnetic circular dichroism in X-ray fluorescence of Heusler alloys at threshold excitation

The results of fluorescence measurements of magnetic circular dichroism (MCD) in Mn L_2,L_3 X-ray emission and absorption for Heusler alloys NiMnSb and Co2MnSb are presented. Very intense resonance Mn L_3 emission is found at the Mn 2p_3/2 threshold and is attributed to a peculiarity of the threshold excitation in materials with the half-metallic character of the electronic structure. A theoretical model for the description of resonance scattering of polarized x-rays is suggested.Comment: 3 pages, 2 figures. Discussed at conferences, submitting process in progres

Anti-Kondo resonance in transport through a quantum wire with a side-coupled quantum dot

An interacting quantum dot side-coupled to a perfect quantum wire is studied. Transport through the quantum wire is investigated by using an exact sum rule and the slave-boson mean field treatment. It is shown that the Kondo effect provides a suppression of the transmission due to the destructive interference of the ballistic channel and the Kondo channel. At finite temperatures, anti-resonance behavior is found as a function of the quantum dot level position, which is interpreted as a crossover from the high temperature Kondo phase to the low temperature charge fluctuation phase.Comment: 4 pages Revtex, 3 eps figure