Thermodynamic properties of the Cu−Sn and Cu−Au systems by mass spectrometry

The activities and partial molar heats of mixing have been determined in the liquid Cu?Sn system at 1320°C and the liquid Cu?Au system at 1460°C. The experimental technique consisted of the analysis of Knudsen cell effusates with a T.O.F. mass spectrometer. The ion current ratio for the alloy components was measured for each system over a range of temperature and composition and the thermodynamic values calculated by a modified Gibbs-Duhem equation. Both systems exhibited negative deviations from ideal behavior. The results can be partially represented by the equations $$\begin{gathered} \log \gamma _{Cu} = - 0.0175x^2 _{Sn} - 0.302 (0 \leqslant x_{Cu} \leqslant 0.20) \hfill \\ log \gamma _{Sn} = - 0.342x^2 _{Cu} + 1.084(0 \leqslant x_{Sn} \leqslant 0.20) \hfill \\ \end{gathered} $$ for the Cu?Sn system at 1320°C and by $$\begin{gathered} \log \gamma _{Cu} = - 0.703x^2 _{Au} - 0.083(0 \leqslant x_{Cu} \leqslant 0.52) \hfill \\ \log \gamma _{Au} = - 1.057x^2 _{Cu} + 0.098(0 \leqslant x_{Au} \leqslant 0.47) \hfill \\ \end{gathered} $$ for the Cu?Au system at 1460°C.     

High speed wire coating by withdrawal from a bath of viscoelastic liquid

Data are presented for the thickness H_∞ of liquid coating entrained by continuous withdrawal at speed U of a wire of radius R from the free surface of a large bath. For Newtonian fluids of viscosity μ, density ρ and surface tension σ, the data are carried out to coating speeds beyond the applicability of current theories, to Capillary numbers of nearly one hundred. In the high speed range the data, which cover several orders of magnitude in viscosity, can be well represented by the equation for U_μ/σ = N_ca > 3. All data presented are at an essentially constant Goucher number of 0.08, where N_Go ≡ R(ρg/2σ)^1/2. Data for viscoelastic fluids show phenomena quite distinct, qualitatively and quantitatively, from Newtonian observations. In particular, strongly elastic fluids show a markedly reduced ability to be entrained onto the wire. Further, the coating thickness appears to become independent of Capillary number at high speed.     

The cardiovascular effects of diazepam and of diazepam and pancuronium during fentanyl and oxygen anaesthesia

A study of the physiological behaviour of the synthetic compound Orthonil (alpha-chloro-beta-(3-chloro-o-tolyl)-propionitrile revealed a strong auxin activity in higher plants. Otherwise, Orthonil appeared not to be a herbicide-auxin. It is metabolized intensively in plant tissues. Among the identified metabolites, two compounds were detected which also exert a high auxin activity. It is concluded that at least a part of the apparent auxin activity of Orthonil may be due to alpha-(3-chloro-o-tolyl) acetic acid, one metabolite of Orthonil. Although Orthonil strongly stimulates elongation growth, this growth is not accompanied by a stimulated ethylene evolution as is the case with other auxins. A possible metabolic pathway of Orthonil is discussed.     

Adaptation of the liquid chromatograph as a micro-reactor; immobilised lactase kinetics

A catalytic, micro-reactor system has been developed using a modified liquid chromatograph with an ultraviolet spectrophotometer detector. The continuous flow, micro-reactor method has been adapted to the measurement of the activity of enzyme catalysts immobilised on porous glass beads. The system offers advantages over other systems in terms of convenience and provisions for steady-state analysis and control. The speed and ease of obtaining reproducible data make it feasible to study the efficacy of immobilisation techniques systematically and to explore liquid chromatographic reactor methods further. The kinetic data obtained were compatible with those found with other methods for the hydrolysis of o-nitrophenyl-β-D-galactopyranoside with immobilised lactase from the fungus Aspergillus niger.     

Multiple necking of tungsten fibers in a brass-tungsten composite

A model composite system, brass-tungsten, was used to study the effect of multiple necking of metal fibers, strain rate, and fiber surface condition on the ductility and deformation behavior of uniaxial metal matrix composites. Low volume percent (<20 vol pct) composites were made using brass (90 Cu-10 Zn) powders and tungsten wires. Tungsten wires contained in plastically deformed composites exhibited numerous necks per length of wire, with an average spacing between necks of 3 to 5 wire diameters. Composite ductility was shown to increase with decreasing multiple neck spacing and increasing percent reduction-in-area at the necks and was generally independent of strain rate. The multiple necking of tungsten wires in a brass matrix was found to result from local strain hardening of the brass matrix in the vicinity of each neck enabling the matrix to control composite deformation locally. Degrading the brass-tungsten interfacial bond by electropolishing the tungsten wires and coating them with graphite had no effect on the multiple necking phenomenon and composite ductility.