Dissolution kinetics of cerium from red mud

Leaching kinetics of rare earth element (REE) cerium (Ce) from red mud was investigated using different shrinking core models. The effect of various pertinent parameters such as acid concentration, liquid–solid ratio (LS), average particle size (PS), temperature and leaching time on the leaching efficiency was studied. The maximum recovery of 70.32% was obtained for 2 M HCl solution and an LS of 20:1 v/v. It was observed that the leaching process was limited by diffusion within the porous ash layer of the solid, thus making it ash diffusion controlled. The apparent activation energy was 11.38 kJ/mol, and the Arrhenius constant was 3.36 min?1.     

3‐Naphthylindole Construction by Rhodium(II)‐Catalyzed Regioselective Direct Arylation of Indoles with 1‐Diazonaphthalen‐2‐(1H)‐ones

The regioselective direct 3‐arylation of indoles with 1‐diazonaphthalen‐2‐(1H)‐ones was developed by means of a rhodium(II) pivalate‐catalyzed cross‐coupling reaction. This procedure provided a variety of novel 3‐naphthylindoles in high yield. The direct coupling of benzofuran, pyrrole or furan with 1‐diazonaphthalen‐2‐(1H)‐ones afforded 2‐ or 3‐naphthyl substituted heterocycles.

     

Some chemical investigations of Amoora rohituka seed proteins

The inadequate supply of protein food, especially in the context of increasing population, has been an important factor in malnutrition in third world countries. Proteins were extracted from de-oiled seeds of Amoora rohituka, a potential source of non-conventional seed, in aqueous solutions of various pHs or by different concentrations of NaCl, KCl, CaCl₂ and MgSO₄ at pH 7.0. The nitrogen content of seeds and de-oiled seeds showed good protein content. Fractionation of protein was done to separate albumin, globulin, prolamine and glutelin. Gel-permeation chromatography on Sephadex G-200 revealed the presence of six components. PAGE identified different polypeptide bands in the range of 15.5–67.6 kDa in the total protein isolate (TPI) as well as in protein fractions. Amino acid analysis of TPI and fractions isolated identified 16 amino acids, most of which are essential. Studies on surface topographies of proteins and seed flour by scanning electron microscope are also incorporated.     

Grain Boundary Space Charge Effect and Proton Dynamics in Chemically Stable Perovskite‐Type Ba0.5Sr0.5Ce0.6Zr0.2Gd0.1Y0.1O3−δ (BSCZGY): A Case Study on Effect of Sintering Temperature

The present study reports the effect of sintering temperature on the proton dynamics of perovskite‐type Ba_0.5Sr_0.5Ce_0.6Zr_0.2Gd_0.1Y_0.1O_3?δ (BSCZGY) by establishing a co‐relation between the grain‐boundary (GB) space charge effect, electrical conductivity and dielectric loss of the BSCZGY samples sintered at 1300°C, 1400°C, and 1550°C for 20 h in air. Although, the GBs are the main source of resistance in BaZrO₃ based ceramic proton conductors, we show that the GB impedance disappeared above 450°C and 300°C, respectively, for BSCZGY samples sintered at 1300°C and 1400°C. Interestingly, the BSCZGY sample sintered at 1550°C showed absence of GB contribution to total conductivity even at 200°C. The GB electrostatic potential [?(0)] was found to vary between 0.35–0.38 V and 0.4–0.45 V, respectively, for the samples sintered at 1300°C and 1400°C at 200°C–300°C. The migration energy (E_m) of the protons was found to be 0.71, 0.65 and 0.58 eV for the sample sintered at 1300°C, 1400°C and 1550°C, respectively.     

Kinetics of electrophoretic deposition ofβ-alumina

The equations describing electrophoretic deposition, proposed by Hamakar Avgustinik and coworkers, have been verified in the case ofβ-alumina suspended in isoamyl alcohol. The variation of electrophoretic yield with (i) concentration of suspension, (ii) extent of grinding the suspension, (iii) temperature of the suspension, and (iv) electrode separation was studied. The effect of addition of glycol monethyl ether was also investigated. The effect of various parameters on the electrical conductivity of the suspension, which in turn influences the yield, was noted.     

Confinement of an antiferroelectric liquid crystal in a polymer nanonetwork: thermal and dielectric behaviour

We report the thermal and dielectric investigations on a liquid crystal exhibiting an antiferroelectric phase and confined in a polymer network of sub-micron dimensions. Two different photo-polymerizable monomers have been employed for the purpose: one of them (HDDA) is bereft of any aromatic parts, while the other (RM82) contains aromatic as well as aliphatic units and, in fact, forms a liquid crystalline phase in its monomeric state. The polymerization, which is carried out in the presence of the liquid crystalline host, is expected to yield a nanosegregated structure for HDDA and blended structure for the RM82 case, the difference reflecting the morphologies of the networks, as evidenced by SEM images. Surprisingly, even a small concentration of the latter polymer added to the former variety has substantial influence on the morphology. The main work focusses on calorimetry and dielectric relaxation spectroscopy of the host liquid crystal confined in these nanonetworks created by the polymers, which can be considered to form virtual surfaces with a finite anchoring energy. We have investigated the in-phase and antiphase modes in the antiferroelectric phase, and the soft mode in the paraelectric phase preceding the antiferroelectric phase. The relaxation frequencies of all these modes are substantially influenced by the network, with the results showing certain surprises in cases containing both HDDA and RM82.     

Transverse Properties of Carbon Fibres by Nano-Indentation and Micro-mechanics

In this study the transverse modulus of three high modulus (M40, M46 and K63712) carbon fibres has first been measured directly by nano-indentation measurements. Transverse tensile tests on unidirectional epoxy composites were then performed, and the comparison was made between transverse fibre properties from indentation and those needed to obtain the measured transverse composite modulus using micromechanics expressions. The latter tended to underestimate values from indentation, by up to 36%, and reasons for this are discussed. Values of transverse fibre modulus determined by both methods decrease as longitudinal fibre modulus increases.     

Drosophila to Explore Nucleolar Stress

Nucleolar stress occurs when ribosome production or function declines. Nucleolar stress in stem cells or progenitor cells often leads to disease states called ribosomopathies. Drosophila offers a robust system to explore how nucleolar stress causes cell cycle arrest, apoptosis, or autophagy depending on the cell type. We provide an overview of nucleolar stress in Drosophila by depleting nucleolar phosphoprotein of 140 kDa (Nopp140), a ribosome biogenesis factor (RBF) in nucleoli and Cajal bodies (CBs). The depletion of Nopp140 in eye imaginal disc cells generates eye deformities reminiscent of craniofacial deformities associated with the Treacher Collins syndrome (TCS), a human ribosomopathy. We show the activation of c-Jun N-terminal Kinase (JNK) in Drosophila larvae homozygous for a Nopp140 gene deletion. JNK is known to induce the expression of the pro-apoptotic Hid protein and autophagy factors Atg1, Atg18.1, and Atg8a; thus, JNK is a central regulator in Drosophila nucleolar stress. Ribosome abundance declines upon Nopp140 loss, but unusual cytoplasmic granules accumulate that resemble Processing (P) bodies based on marker proteins, Decapping Protein 1 (DCP1) and Maternal expression at 31B (Me31B). Wild type brain neuroblasts (NBs) express copious amounts of endogenous coilin, but coilin levels decline upon nucleolar stress in most NB types relative to the Mushroom body (MB) NBs. MB NBs exhibit resilience against nucleolar stress as they maintain normal coilin, Deadpan, and EdU labeling levels.