Synthesis of polycarbonate containing in-chain 4-N,N-dimethylamino-4′-nitrostilbene via ring-opening polymerization

Summary We have successfully synthesized a new NLO chromophore based on 4-N,N-dimethylamino-4-nitrostilbene which contains bisphenol functionality for polycarbonate preparation. Chromophore-4 was used to make macrocyclic carbonate oligomers and the oligomers were converted to polycarbonate via ring-opening polymerization in solution.     

Mass determination of the fatty acids released from tannin-stimulated rabbit alveolar macrophages

Previous studies with macrophages that had been prelabeled with [¹⁴C]arachidonic acid (20∶4) have shown that condensed tannin is a potent agonist for the release of arachidonic acid. However, it has not been demonstrated that the percentage release of [¹⁴C]20∶4 accurately reflects the metabolic activity of the endogenous 20∶4 pool. In order to measure the 20∶4 mass release relative to the total cellular 20∶4 pool, the free fatty acids of freshly isolated alveolar macrophages were derivatized with a fluorescent reagent, and then separated and quantified by high-performance liquid chromatography. The amounts of esterified fatty acids were measured by gas chromatography of the methyl esters. Free fatty acid levels were compared to those of the total esterified plus unesterified fatty acids to determine the actual percentage released of each fatty acid. Tannin-stimulated release of 20∶4 mass reflected that previously reported for the release of [¹⁴C]20∶4 label but at a slower rate and at a much lower percentage indicating that [¹⁴C]20∶4 had been incorporated into part of a more reactive pool. The specificity of the fatty acid release induced by tannin and β-1,3-glucan, a known agonist for 20∶4 release, was also examined. Both agonists promoted an increase in the levels of free 20∶4 and of other fatty acids. A comparison of the absolute increases of each of the fatty acids indicated that tannin caused a preferential increase in the mass of free 20∶4, whereas β-1,3-glucan evoked a selective increase in the mass of 16∶0. Deceased.     

Chemical beneficiation of coal with aqueous hydrogen peroxide/sulphuric acid solutions

The removal of sulphur and ash from coal treated with aqueous hydrogen peroxide/sulphuric acid solutions has been studied at ambient temperature, under a variety of experimental conditions. Almost complete elimination of the sulphate and the pyritic sulphur was observed in most cases, as well as substantial reduction in the ash content. The other components of the organic coal matrix were not affected to a significant extent, indicating high selectivity of the $\text{H}{}_2\text{O}{}_2\text{H}{}_2\text{SO4}$ system towards sulphur oxidation. An optimal H₂SO₄ concentration was established, above which the acid was found to have an adverse effect on the oxidation of pyrite by hydrogen peroxide.     

Equilibrium catalyst from a fluidized catalytic cracking unit separated by metal content by using carbon nanotubes and a biphasic system

During fluid catalytic cracking (FCC) operations FCC catalyst particles become contaminated with various metals. These metals impact FCC performance and currently requires equilibrium catalyst (ECAT) mixtures consisting of a blend of FCC particles with a time spent in the reactor ranging from minutes to several months to be continuously extracted and sold as low value products or sent to landfills. Here a unique method to recycle FCC ECAT particles is presented, which separates ECAT particles by metal content by synthesizing carbon nanotubes and nanofibers on the ECAT particles surface and using a biphasic system. ECAT with low metal content can be sent back to the FCC unit for further use while ECAT with high metal content can be used for other purposes. Further, we show these treated ECAT materials of high metals content will absorb oil on the surface of water and may prove useful for oil spill clean-up applications.     

Microstructure, mechanical and tribological properties of Cr1−xAlxN films deposited by pulsed-closed field unbalanced magnetron sputtering (P-CFUBMS)

Nanocrystallized Cr_1−xAl_xN films with various Al contents (0 to 68 at.%) were deposited by pulsed closed field unbalanced magnetron sputtering (P-CFUBMS). The effects of aluminum content on the microstructure, mechanical and tribological properties of the Cr_1−xAl_xN films have been investigated. It was found that the hardness and elastic modulus of Cr_1−xAl_xN films increased with increasing Al contents in the films and reached the highest value of 36 GPa and 370 GPa, respectively, at an Al content of 58.5 at.%. Addition of Al beyond 64.0 at.% resulted in a change in crystal structure from B1 cubic to B4 hexagonal phase. The wear resistance improved gradually with the increase of Al in the Cr_1−xAl_xN films. A combination of the abrasive and adhesive wear mechanism was proposed based on the SEM and EDS analysis of the wear track. The steady state dry coefficient of friction measured against a WC ball for the Cr_1−xAl_xN films were in the range of 0.36-0.55, and the wear rate was in the 10^− 6 mm³ N^− 1 m^− 1 range.     

Elemental Powder Approaches to Ni3Al-Matrix Composites

Reactive sintering and hot isostatic compaction of mixed elemental powders have been combined to fabricate full density NiAl intermetallic-matrix composites. This process involves the formation of the matrix compound from its elemental constituents through an exothermic reaction. Dispersed ceramic phases inhibit direct consolidation, necessitating superposition of external pressure via hot isostatic compaction to obtain full density. The latter process is termed reactive hot isostatic pressing (RHIP). Because of its flexibility and low cost, this fabrication process merits attention as a means of preparing monolithic compounds and intermetallic-matrix composites.     

Effects of solid solution alloying on creep deformation of aluminum

The effects of solid solution alloying on the creep-rupture properties, deformation characteristics, ductility, and fracture of pure aluminum were studied by means of creep-rupture tests on polished specimens of three alloys each of Al-Cu (0.24, 0.79, and 2.05 pct Cu), Al-Zn (4.93, 9.89, and 19.78 pct Zn), and Al-Mg (0.94, 1.92, and 5.10 pct Mg) at 500°, 700°, and 900°F.     

Chromium distribution between liquid iron and molten basic slags

An equilibrium study was made of the distribution of chromium and oxygen between liquid iron, containing less than 1 pct Cr, and simple slags of the CaO(MgO)-SiO₂-FeO-Cr₂O₃ type in the temperature range 1526° to 1734°C The effects of slag oxidation, temperature, and basicity were observed.