William Powrie

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This paper discusses the mechanisms involved in the compression of domestic waste, and how the resulting compression behaviour may be modelled. Reference is made to experimental data illustrating the effect of gas content and pore water pressure on bulk density and drainable porosity, and a theoretical model able to reproduce some but not all features of(More)
Cultured Chinese hamster ovary (CHO) cells were exposed for 3 h to furan and 6 furan derivatives (furfural, furfuryl alcohol, 5-methyl furfural, 2-methyl furan, 2,5-dimethyl furan and 2-furyl methyl ketone). Each of the 6 furan derivatives induced a relatively high frequency of chromatid breaks and chromatid exchanges in the absence of a liver microsomal(More)
Chlorogenic acid, a compound which occurs naturally in many food items, was assayed for genotoxic activity in 3 different test systems: reverse mutations in the preincubation test with Salmonella typhimurium, gene conversion with Saccharomyces cerevisiae strain D7, and chromosome aberrations in Chinese hamster ovary (CHO) cells. Chlorogenic acid was(More)
The paper investigates reproducing the effects of confining pressure on the behaviour of scaled railway ballast in triaxial tests in discrete element models (DEM). Previous DEM work, using a standard Hertzian elastic contact law with an elastic–perfectly plastic tangential slip model, has been unable to replicate the behaviour observed in laboratory tests(More)
Various methods were assessed for the synthesis of 7-ketocholesterol and epimeric 7-hydroxycholesterols. Upon the oxidation of cholesteryl acetate with t-butyl chromate, the resulting ketosterol acetate crystallized from methanol consisted of about 25% unoxidized cholesteryl acetate. After the sterol acetates were hydrolyzed in an aqueous K2CO3 medium,(More)
Chloroform extracts of fecal material from 4 subjects on normal mixed western diets were fractionated to obtain an acid fraction and a hexane extract containing neutrals and bases. The acid fraction from at least 2 of the donors induced an elevated frequency of chromosomal aberrations and exchanges in Chinese hamster ovary (CHO) cells. Since acid steroids(More)
The Salmonella typhimurium assay was used to determine the antimutagenic effect of products of 2 non-enzymatic browning reactions obtained by heating a lysine-fructose mixture at 121 degrees C for 1 h and by carmelizing D-sucrose at 180 degrees C for 1.5 h. The antimutagenic effect was tested by exposing strain TA1535 in suspension to N-methyl-N'(More)
Cultured Chinese hamster ovary (CHO) cells were exposed for 3 h to caramelized solutions of the sugars sucrose, glucose, mannose, arabinose, maltose and fructose. Each of these caramelized sugars induced a relatively high frequency of chromosome breaks and exchanges in the treated cells. The non-caramelized sugars did not increase the frequency of(More)