Investigation on the Phase Diagram of LiCl-KCl-NdCl<Subscript>3</Subscript> Pseudo-Ternary System

The ternary phase diagram of LiCl-KCl-NdCl₃ system has been investigated by differential thermal analysis (DTA), followed by characterization of the coexisting phases in the solid state by x-ray diffraction, in order to understand the interactions in the NdCl₃-LiCl-KCl ternary system. The results of these experiments showed that LiCl and K₂NdCl₅ form a non binary join section. This divides the LiCl-KCl-NdCl₃ system into two quasi-ternary sections, namely (1) LiCl-KCl-K₂NdCl₅ and (2) LiCl-K₂NdCl₅-NdCl₃ systems. Both are simple eutectic ternary phase diagrams. The ternary eutectic temperatures and eutectic compositions are determined to be 316?±?3 °C and 53.9 mol.% LiCl-38.7 mol.% KCl-7.4 mol.% K₂NdCl₅ in the LiCl-KCl-K₂NdCl₅ quasi-ternary section, while the other eutectic temperature and composition are determined to be 376?±?9 °C and 46.2 mol.% LiCl-32.5 mol.% K₂NdCl₅-21.3 mol.% NdCl₃ in the LiCl-K₂NdCl₅-NdCl₃ quasi-ternary section. A quasi-ternary peritectic reaction is observed at 37.7 mol.% LiCl-36.2 mol.% KCl-26.1 mol.% K₂NdCl₅ at 445?±?1°C. The primary and secondary crystallization temperatures for the samples are deduced from the heating runs of DTA traces, and the phases responsible for the various thermal events are ascertained. Isothermal sections at chosen temperatures and polythermal liquidus projection with isothermal contours are drawn over the ternary phase field.     

Unprecedented Homoleptic Bis‐Tridentate Iridium(III) Phosphors: Facile,Scaled‐Up Production,and Superior Chemical Stability

Bis‐tridentate Ir(III) metal complexes are expected to show great potential in organic light‐emitting diode (OLED) applications due to the anticipated, superb chemical and photochemical stability. Unfortunately, their exploitation has long been hampered by lack of adequate methodology and with inferior synthetic yields. This hurdle can be overcome by design of the first homoleptic, bis‐tridentate Ir(III) complex [Ir(pzpyph)(pz^Hpyph)] ( 1 ), for which the abbreviation (pzpyph)H (or pz^Hpyph) stands for the parent 2‐pyrazolyl‐6‐phenyl pyridine chelate. After that, methylation and double methylation of 1 afford the charge‐neutral Ir(III) complex [Ir(pzpyph)(pz^Mepyph)] ( 2 ) and cationic complex [Ir(pz^Mepyph)₂][PF₆] ( 3 ), while deprotonation of 1 gives formation of anionic [Ir(pzpyph)₂][NBu₄] ( 4 ), all in high yields. These bis‐tridentate Ir(III) complexes 2 – 4 are highly emitted in solution and solid states, while the charge‐neutral 2 and corresponding t ‐butyl substituted derivative [Ir(pzpy^Buph)(pz^Mepy^Buph)] ( 5 ) exhibit superior photostability versus the tris‐bidentate references [Ir(ppy)₂(acac)] and [Ir(ppy)₃] in toluene under argon, making them ideal OLED emitters. For the track record, phosphor 5 gives very small efficiency roll‐off and excellent overall efficiencies of 20.7%, 66.8 cd A^?1, and 52.8 lm W^?1 at high brightness of 1000 cd m^?2. These results are expected to inspire further studies on the bis‐tridentate Ir(III) complexes, which are judged to be more stable than their tris‐bidentate counterparts from the entropic point of view.     

Thermodynamic properties of ternary liquid Cu-Mg-Ni alloys

Magnesium vapor pressures were determined over ternary Cu-Mg-Ni alloys along three isopleths withx _Cu/x _Ni = 2.0, 1.0, and 0.5 using an isopiestic method. Data points were obtained between approximately 20 and 90 at. pct magnesium in the temperature interval from 1050 to 1350 K. Partial thermodynamic properties of magnesium were derived for the liquid phase, and integral Gibbs energies of formation were computed by a Gibbs-Duhem integration. The composition dependence of the activities at 1173 K is shown for the three sections investigated. The experimental integral Gibbs energies of mixing for liquid alloys are compared with the values calculated from binary data by a geometrical formalism.     

Effects of Newtonian heating and thermal radiation on micropolar ferrofluid flow past a stretching surface: Spectral quasi‐linearization method

This study article addressesthe flow and heat transfer characteristics of a magnetite Fe₃O₄ micropolar ferrofluid flow past a stretching sheet. For practical interest, thermal radiation, Newtonian heating, and a heat source or sink are considered in this investigation. A useful Tiwari‐Das nanofluid model is considered to analyze the microstructure and inertial characteristics of the water‐based nanofluids containing iron oxide. The dimensionless nonlinear ordinary differential equations are solved by employing suitable similarity variables. The resulting nonlinear system is solved by the spectral quasi‐linearization method. The effects of different nondimensional parameters on various profiles are shown graphically and explored in detail. It is found that the micropolar ferrofluid exhibits a higher energy distribution than that of a classical micropolar fluid. Compared to the classical micropolar liquid, local skin‐friction is more significant for the micropolar magnetite ferrofluid. In the presence of Newtonian heating, the thermal behavior of the micropolar nanofluid is remarkably better than that of the classical micropolar fluid.     

Recovery of valuable metals from waste printed circuit boards using organic acids synthesised by Aspergillus niveus

Organic acids such as citric acid, itaconic acid and oxalic acid synthesised by Aspergillus niveus were used for the bioleaching of metals from waste printed circuit boards. Bioleaching of valuable metals was performed in one‐step, two‐steps and spent medium approaches using A. niveus. In the absence of waste printed circuit boards (WPCBs), the dry cell weight of A. niveus was higher when compared with the presence of WPCBs. Variations in the dry cell weight were observed for the presence of different particle sizes. The increase in itaconic acid and oxalic acid synthesis was found at a reduced particle size (60–80 mesh) and reached the maximum titre of itaconic acid (22.35 ± 0.87 mM) and oxalic acid (12.75 ± 0.54 mM) in 12 days during the two‐step bioleaching. The maximum recovery of 75.66% Zn, 73.58% Ni and 80.25% Cu from WPCBs was achieved in 15 days in two‐step leaching with particle sizes of the mesh being 60–80.     

An electrochemical meter for measuring carbon potential in molten sodium

Thermodynamic analysis and electrochemical investigations were carried out to evaluate the chemistry and electrode kinetics of a molten carbonate based electrochemical carbon meter for monitoring carbon in molten sodium. Based on the results of investigations a procedure was standardized for assembling the cell. The response of the cell thus assembled could be correlated to the carbon activity in sodium. Impedance studies established that mass transfer at iron membrane was the rate limiting step. Meters were extensively tested in both static and dynamic sodium for evaluating the stability and reproducibility in long term conditions.     

Lithium ion conduction in Li5La3Ta2O12 and Li7La3Ta2O13 garnet-type materials

Electrical properties of the lithium garnets Li₅La₃Ta₂O₁₂ (L5LTO) and Li₇La₃Ta₂O₁₃ (L7LTO) are reported over a wide frequency range from 10 MHz to 0.1 Hz at different temperatures. The structural properties are characterized by powder X-ray diffraction, Scanning electron microscopy with energy dispersive X-ray spectroscopy and Fourier transformation Infrared spectroscopy. By means of the frame work of classical brick layer model (BLM) and of a finite element approach, the ion transport properties of grain and grain boundary for the lithium garnets were analyzed. The specific grain conductivity of 5.0?×?10^?6?S/cm at 40 °C is found for both lithium garnets. Specific grain conductivities and grain boundary conductivities are thermally activated, with activation energies found to be in the range of 0.55–0.61 eV. The total conductivity is found to be depending on the ion conduction of grain boundary. The information on the fraction of contact area α_contact between grains <0.25 is obtained by the finite element approach for Li₇La₃Ta₂O₁₃.     

Poly(dimethylsiloxane-urethane) membranes: effect of linear siloxane chain and caged silsesquioxane on gas transport properties

The effect of poly(dimethylsiloxane) (PDMS) or polypropylene glycol (PPG) linear chain and polyoctahedral oligosilsesquioxanes (POSS) cubic nanoparticles on surface and gas transport properties of poly(dimethylsiloxane-urethane) PDMS-PU or poly(propylene glycol-urethane) (PPG-PU) hybrid membranes were studied. PDMS-PU or PPG-PU hybrid membranes were prepared using PDMS-diol or PPG-diol as a chain extender and diisocyanate with POSS-amine macromonomer as a crosslinker. The macromer synthesized was characterized using FT-IR, ¹H-, ¹³C- and ²⁹Si-NMR spectroscopic methods. The hybrid membranes were characterized by CP-MAS ²⁹Si-NMR, DSC, contact angle, WAXD, AFM and density measurements. The glass transition temperature (Tg) of the hybrid membranes were determined by differential scanning calorimetry (DSC) and were found to be in the range of 176–189°C. The surface free energy was reduced by increasing the POSS-amine crosslinker content of the membranes. The AFM measurement showed phase separation of POSS-amine molecule and PDMS with the urethane matrix on the surfaces. The XRD profiles confirm that the membranes were highly amorphous in nature. The decrease in permeability was observed by increasing the concentration of POSS-amine incorporated hybrid membranes. The selectivities of O₂/N₂ and CO₂/N₂ gas pairs increased with an increase in the POSS concentration. This suggests that the selectivities were dependent mainly on the presence of urethane and ester functional groups in the crosslinker.     

Communication Maps: Exploring Energy Transport through Proteins and Water

Frequency-resolved communication maps provide a coarse-grained, global mapping of energy transport channels in a protein as a function of frequency of modes that carry energy. We illustrate the approach with a study of the homodimeric hemoglobin of Scapharca inaequivalvis, which exhibits cooperativity during ligand binding. We compare energy transport between the two hemes of the unliganded and oxygenated protein, which is mediated by water as well as residues forming a hydrogen-bonding network at the interface between the globules, and lies along the pathway for allosteric transitions observed in time-resolved X-ray studies. Non-equilibrium molecular simulations on energy transport from the heme corroborate the energy transport pathways identified by the communication maps.     

A facile synthesis of mixed soft‐segmented poly(urethane‐imide)–polyhedral oligomeric silsesquioxone hybrid nanocomposites and study of their structure–transport properties

The structure–transport properties of mixed soft‐segmented poly(urethane‐imide) (MSPUI) membranes and their microstructures were investigated. Polypropylene glycol, polycaprolactone diol and bis(3‐aminopropyl)‐terminated polydimethylsiloxane were used as the soft segments in the membrane synthesis via a three‐step polymerization reaction. The chemical structures of the MSPUI membranes were characterized using attenuated total reflectance Fourier transform infrared spectroscopy. Morphology and surface properties of the membranes were studied using scanning electron and atomic force microscopy techniques. Surface energy measurements indicated the enrichment of the hydrophobic soft segment in the membranes. The amorphous nature of the polymers was analysed using wide‐angle X‐ray diffraction. The effect of morphology on the permeability and selectivity of the membranes is discussed. Finally, membrane structure–transport property relationships were correlated. © 2013 Society of Chemical Industry