Monotone norms

Summary The idea of norms monotone in the nonnegative orthant is extended to partially ordered finite dimensional real spaces. Relations between the monotonicity of a norm and of the dual and the subordinate matrix norm are investigated.     

Dominant vortices in impinging jet flows

A novel method of flow visualization by dye was used in conjunction with numerical solutions to investigate the formation stages of large stationary vortical motions located in the “trajectory bend” centers of impinging jet flows. The vortices dominate the flowfield and were found to have profound influence on the wall transport phenomena. Depending on the value of Reynolds number, four regimes were identified with different flow character.     

Ureas as Solvents for Chemical Investigations

N-Alkylated ureas, including cyclic derivatives, are readily obtained pure. These stable compounds are already used as industrial solvents owing to their considerable solvent power, their wide liquid range, and their favorable dielectric constants and dipole moments. They are being increasingly employed as reaction media for electrochemical and analytical studies.     

Crystallographic determination of metal surfaces with helium scattering

Helium-surface diffraction data has been used to construct the interaction potential between a Helium atom and a metal surface. The constructed potential fits experimental data for all beam energies and angles of incidence and more importantly is independent of beam energy. Such a potential essentially consists of two parts: a short range repulsive corrugated potential due to electronic overlap, and a long range attractive potential due to dispersion forces. We have generated potentials for He scattering for Ni, Cu and Au and in all cases found excellent agreement with experiments. We also report that the repulsive part of the He scattering potential can be obtained rather simply from first principles without adjustable parameters. This suggests that one can determine surface crystallography from first principles without adjustable parameters.     

The reaction of nitrous oxide with rhodium

A clean rhodium filament at room temperature is highly reactive towards nitrous oxide. The oxygen atom of the N₂O molecule is adsorbed with a sticking probability of 0.45 whilst the nitrogen atoms appear in the gas phase as molecular nitrogen. The room temperature uptake of oxygen is about 5 × 10¹⁴ atom cm^?2 and is independent of nitrous oxide pressure in the range 3.5 × 10^?8 to 1.1 × 10^?6 torr. The adsorption curve is of typical form with an initial region of essentially constant sticking probability. For the first 80% of adsorption at room temperature the shape is satisfactorily accounted for if molecules are able to visit 4–5 adsorption sites whilst held in a weakly-bonded precursor state.     

Conditions for static balance for the post-Newtonian two-body problem with electric charge in general relativity

The usual condition for static balance, for two bodies with masses and charges m_i and e_i (i = 1, 2), is $\text{e}{}_{\mathrm{i}}\text{=±G}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{m}{}_{\mathrm{i}}$. From a post-Newtonian analysis of the two-body problem, an alternate condition for static balance $\text{e}{}_{\mathrm{i}}\text{=±(Gm}{}_1\text{m}{}_2\text{)}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ has been found. We do not know if this condition is exact beyond the post-Newtonian approximation.     

Separation of fatty acid esters and fatty acid ester derivatives using preparative scale sequential gas-liquid chromatographic equipment

Summary A sequential continuous chromatographic refiner (SCCR-2) for preparative-scale GLC up to 200°C is described. The separating capabilities and other characteristics of the SCCR-2 unit have been investigated using fatty acid ester mixtures of different separation difficulty and volatility. The feed mixtures selected had separation factors () between 1.1 and 1.5 and required operating temperatures between 110 and 200°C, while using FFAP (free fatty acid phase) on Chromosorb W or OV-275 (a cyanosilicone) on Chromosorb P. Initially the separation of a 50/50 v/v mixture of methyl chloroacetate/ethyl lactate (1.5) was studied and the ability of the SCCR-2 unit to separate the mixture into two products with purities in excess of 99.8% has been demonstrated at feedrates up to 80 cm³h^–1 and temperatures between 110 and 130°C. For the more difficult system ethyl chloroacetate/ethyl lactate (1.2) the column was too short for successful separation, although purities of about 95% for one product stream were obtained at feedrates of 33 cm³ h^–1 at 125°C. Preliminary studies on the recovery of -linolenic acid from fungal oil, at temperatures of 200°C are reported. Although this equipment has been demonstrated on the laboratory scale it is amenable to scale up to production levels. Partition coefficient data for several fatty acid solutes were determined using a comerical analytical scale GLC and some of the most favoured stationary phases for the GLC of fatty acids.