Comparative evaluation of extraction of tetra- and hexa-valent neptunium ions by CMPO in a room temperature ionic liquid

ABSTRACT

Solvent extraction studies were performed to understand the extraction behavior of Np⁴⁺ and NpO₂ ²⁺ from acidic feeds with CMPO (octyl (phenyl)-N,N-diisobutyl carbamoyl methyl phosphine oxide) dissolved in 1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide, a water immiscible ionic liquid. Slope analyses on the distribution data revealed the extraction of ML₂ type species, where M = Np⁴⁺ or NpO₂ ²⁺, and L = CMPO. Studies were also carried out with Pu⁴⁺ and UO₂ ²⁺ under identical conditions. The nature of the extracted species was found to vary with the nature of the ionic species.     

All-optical method for the addition of binary data by nonlinear materials

An all-optical system for the addition of binary numbers is proposed in which input binary digits are encoded by appropriate cells in two different planes and output binary digits are expressed as the presence (=1) or the absence (=0) of a light signal. The intensity-based optical XOR and AND logic operations are used here as basic building blocks. Nonlinear materials, appropriate cells (pixels), and other conventional optics are utilized in this system.     

High Na+ conducting Na3Zr2Si2PO12/Na2Si2O5 composites as solid electrolytes for Na+ batteries

Sodium superionic conductor Na₃Zr₂Si₂PO₁₂ (NZSP) is a promising material as a solid electrolyte for sodium-ion batteries. The highest conductivity of ∼1.0 mS/cm at room temperature (RT) was reported for the compound with a Na content of approximately 3.3 per formula unit (f. u.) and when the material is synthesized with a final sintering temperature ≥1220°C. Herein, we propose a new synthesis method to enhance the conductivity of the NZSP by liquid-phase sintering with the optimum amount of additive of amorphous-Na₂Si₂O₅. In this regard, a series of composite materials were prepared by mixing Na₃Zr₂Si₂PO₁₂ with amorphous-Na₂Si₂O₅ (NZSP/NS-x wt.%; with x = 0.0, 2.5, 5.0, 7.5, 10.0) and sintering at a lower temperature of 1150°C. Enhanced conductivity of 1.7 mS/cm at RT has been achieved for the Na₃Zr₂Si₂PO₁₂/Na₂Si₂O₅-5.0 wt.% (NZSP/NS-5.0) composite. The effects of additives on the NZSP phase formation, microstructure, and ion conductivity have been investigated by XRD, MAS NMR, SEM, and impedance spectroscopy. Our study demonstrates that the higher conductivity of the NZSP/NS-5.0 composite is caused by the combined effect of increased Na content in the NZSP phase (by diffusion of Na⁺ ions from the liquid phase of NS to bare NZSP phase), higher density, and microstructures with lesser pores.     

Dissecting the Roles of Cuticular Wax in Plant Resistance to Shoot Dehydration and Low-Temperature Stress in Arabidopsis

Cuticular waxes are a mixture of hydrophobic very-long-chain fatty acids and their derivatives accumulated in the plant cuticle. Most studies define the role of cuticular wax largely based on reducing nonstomatal water loss. The present study investigated the role of cuticular wax in reducing both low-temperature and dehydration stress in plants using Arabidopsis thaliana mutants and transgenic genotypes altered in the formation of cuticular wax. cer3-6, a known Arabidopsis wax-deficient mutant (with distinct reduction in aldehydes, n-alkanes, secondary n-alcohols, and ketones compared to wild type (WT)), was most sensitive to water loss, while dewax, a known wax overproducer (greater alkanes and ketones compared to WT), was more resistant to dehydration compared to WT. Furthermore, cold-acclimated cer3-6 froze at warmer temperatures, while cold-acclimated dewax displayed freezing exotherms at colder temperatures compared to WT. Gas Chromatography-Mass Spectroscopy (GC-MS) analysis identified a characteristic decrease in the accumulation of certain waxes (e.g., alkanes, alcohols) in Arabidopsis cuticles under cold acclimation, which was additionally reduced in cer3-6. Conversely, the dewax mutant showed a greater ability to accumulate waxes under cold acclimation. Fourier Transform Infrared Spectroscopy (FTIR) also supported observations in cuticular wax deposition under cold acclimation. Our data indicate cuticular alkane waxes along with alcohols and fatty acids can facilitate avoidance of both ice formation and leaf water loss under dehydration stress and are promising genetic targets of interest.     

GilR,an Unusual Lactone‐Forming Enzyme Involved in Gilvocarcin Biosynthesis

Last at last : The terminal step of the gilvocarcin V (GV) biosynthetic pathway is an unusual lactone formation. Here we show that the enzyme, GilR, dehydrogenates the hemiacetal moiety of pregilvocarcin V to the lactone found in GV by using covalently bound FAD.

     

Effect of inhibitors on flammability range of flames produced from LPG/air mixtures

Burning velocities of Liquefied Petroleum Gas/air flames of different fuel/air compositions have been measured by the flat-flame method originally developed by Egerton and Powling, and the effects of inhibitors such as chlorinated hydrocarbons (chloroform, methylene dichloride, carbon tetrachloride) on the burning velocities have been investigated. The flammability limits at different fuel/air compositions have also been measured. The difference between upper and lower limits of flammability was narrowed by the addition of inhibitors in the order carbon tetrachloride chloroform methylene dichloride, i.e. the inhibiting effect increased with increase in the number of chlorine atoms. The relative effectiveness of different inhibitors has been expressed as an inhibition efficiency, and it has been found that an interesting correlation exists between the inhibition efficiency (also the narrowing of limits, and the maximum burning velocity) and the number of (dissociable) chlorine atoms present in the molecule of inhibiting compound. Other factors were the degree of dissociation of the inhibiting molecule in the flame, and the concentration of the inhibitor in the fuel/air mixture; the effect of small concentrations was that of specific chemical inhibition whereas at higher concentrations dilution effects were dominant. At the upper limit the flame has maximum tendency to flash back in an ordinary burner and the combustion wave may develop into a detonation wave inducing an explosion hazard. Hence upper explosion limit may be considered an index of explosion risk. The inhibitors lower this largely by reducing the concentration of free radicals in the flame boundary, increasing the difficulty of ignition, and thus increasing safety. A large difference has been found between the experimental and calculated value of the upper limit for the pure gas, probably owing to the chemical effects of ethylene via production of acetaldehyde which catalyses the combustion.