A new method to detect the use of banned azo dyes in the manufacture and treatment of coloured textiles and leather is described. The determination of the azo dyes was made by quantification of aromatic amines generated by reductive cleavage in a citrate buffer medium. The aromatic amines were then extracted from 1 mL of the reaction solution by means of solid phase microextraction (SPME) and determined by gas chromatography/mass spectrometry (GC/MS). We also evaluate accuracy, precision, range of linearity and limit of detection for the eighteen aromatic amines investigated, and show that the method is comparable with current established methods. Copyright 1999 John Wiley & Sons, Ltd.
A model-scale experimental investigation of an installed jet–pylon–wing configuration was conducted at the University of Southampton, with the scope to study the effect a pylon has on noise generation and to clarify its impact on the fluctuating wall-pressure load. The set-up consisted of two single-stream nozzles, a baseline axisymmetric annular nozzle and a partially blocked annular pylon nozzle. The nozzles were tested first isolated and then installed next to a NACA4415 aerofoil ‘wing’ at a single nozzle–wing position. The jet Mach number was varied between
$0.5 \leq M_{{j}} \leq 0.8$
and measurements were performed both under static and in-flight ambient flow conditions up to
${M_{{f}} = 0.2}$
. The jet flow-field qualification was carried out using a single-velocity-component hot-wire anemometer probe. The pressure field on the wing surface was investigated using two miniature wall-pressure transducers that were flush-mounted in the streamwise and spanwise directions within the pressure side of the wing. A linear ‘flyover’ microphone array was used to record the noise radiated to the far field. The unsteady pressure data were analysed in both time and frequency domains using multi-variate statistics, highlighting a far-field noise reduction provided by the presence of the pylon only in the installed case. Furthermore, the wake field generated behind the pylon is seen to significantly modify the wall-pressure fluctuations, particularly at streamwise locations close to the pylon trailing edge.
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