Comparison of the separation of lactic acid and l-leucine by liquid emulsion membranes

A mass transfer model originally proposed for the permeation of zinc and l-phenylalanine was slightly modified and used for calculating the mass transfer resistances in lactic acid permeation (using the secondary amine Amberlite LA-2 as a carrier) and l-leucine permeation (using the quaternary ammoniumchloride Aliquat 336 as a carrier). The results show that under optimized conditions lactic acid permeation is controlled by the rate of reaction and that l-leucine permeation is controlled by the rate of reaction and the diffusion through the emulsion globule. The model results were compared with batch experiments separating lactic acid and l-leucine from real fermentation broths. The comparison shows that the separation rate is affected by co-transport of pH regulating agents and to a smaller extent by the co-transport of water.     

Toxicity testing of oil-contaminated drilling cuttings

The luminescent bacterium Photobacterium phosphoreum has been used to examine samples of oily drilling cuttings from the sea bottom in the vicinity of a North Sea oil production platform. Because the presence of any fine particulate matter results in a depression of the bioluminescence, the cuttings must first be extracted and the extract filtered before mixing with the bacterial suspension. A sea-water extract of a low toxicity drilling oil gave a small but significant depression of bioluminescence, but extracts with 1% v/v ethanol or DMSO gave a 50% greater depression. Samples of cuttings from different depths (representing different ages, up to 15 years) showed a different pattern, with similar effects from the aqueous and the mixed-solvent extracts. It is assumed that the toxic component therefore is not originating from the drilling mud oil, but from some additive which has a rather higher solubility in water than the hydrocarbons.     

Entrapping homogeneous catalysts by sol-gel methods: the bottom-up synthesis of catalysts that recycle and cascade

Homogeneous catalysts entrapped in silica matrices, including ionic liquid containing 'ionogels', exhibit high selectivity, unexpected activity and excellent recyclability.     

Mechanical properties of aluminium laminates produced by accumulative roll bonding

Laminates of high and commercial purity aluminium layers were processed by accumulative roll bonding performed up to ten cycles. The mechanical properties were measured by tensile testing. Both yield strength and ultimate tensile strength increase with higher number of cycles. The fracture strain is decreased through the first ARB cycle, but increases during further processing to reach a maximum after the sixth cycle. It is found that the development of the microstructure, especially in the high purity layers, strongly influences the mechanical properties.     

Characterization of North Sea drilling cuttings by metal binding form patterns and diffuse reflectance spectroscopy (DRIFT)

Samples of marine sediments collected in the vicinity of and remote from an oil production platform have been analysed for several metals (Cr, Cu, Fe, Mn, Ni, and Pb) and for total hydrocarbons. The same samples have been examined by diffuse reflectance IR spectroscopy (DRIFT) after drying, and an attempt has been made to classify the samples according to the patterns of the metals and the reflectance spectra, and to correlate this classification with that based on the sampling site. It is suggested that DRIFT is a faster technique than the conventional solvent-extraction IR method for total hydrocarbons and — while less sensitive — is adequate for screening such samples for significant levels of hydrocarbon pollution. Classification of the samples according to the metals present also distinguishes between the two groups of samples.     

Polarization of protons from the C(d,p)C reaction

The polarization of protons from the ¹²C(d, p)¹³C reaction has been measured for deuteron bombarding energies between 3.9 and 5.8 MeV. Angular distributions of the polarization for protons leaving ¹³C in its ground state have been measured for laboratory angles between 10° and 135° at several energies in the vicinity of a resonance at 4 MeV in order to determine the effect of that resonance on the polarization. Additional measurements were made at 0.4 MeV intervals throughout the energy range. These measurements demonstrate that the compound-nuclear resonances observed in the cross section do not significantly alter the polarization angular distributions except at back angles. The shape of the observed polarization angular distributions at all energies is quite similar to previous results obtained for deuteron bombarding energies up to 15 MeV.     

Determination of tin in poly(vinyl chloride) by atomic-absorption spectroscopy

A simple procedure is described for the determination of tin in PVC by atomic-absorption spectroscopy with an air-hydrogen flame, after wet digestion of the sample with sulphuric acid and hydrogen peroxide.