Factors affecting prior austenite grain size in low alloy steel

The effect of varying normalising and hardening temperatures on the prior austenite grain size in a low alloy Cr–Mo–Ni–V steel has been examined. An initial relative insensitivity of grain size to increasing austenitising temperature was observed followed by a sudden growth of grains at approximately 1000 °C. A detailed study of the precipitates in the steel showed the presence of a bimodal size distribution of vanadium carbides. The grain size increase is attributed to a decrease in volume fraction and an increase in size of V₄C₃ particles with increasing temperature.     

Effect of phase proportions on deformation and cavitation of superplastic α/β brass

Studies have been made, using metallographic and precision density techniques, of the deformation and cavitation behaviour during superplastic tensile straining at 873 K of three microduplex/ brasses which, as a consequence of varying composition, contained varying proportions of and phases. It was observed that both strain-rate sensitivity and elongation-to-failure passed through a maximum when approximately equivolume proportions of the two phases were present. Cavitation, on the other hand, decreased rapidly as the volume fraction of phase was increased. The cavitation behaviour was attributed to the relative abilities of the phases to accommodate grain boundary sliding. When a high proportion of phase is present accommodation is minimal and cavity nucleation. occurs readily. Evidence is presented to show that grain-boundary sliding plays a predominant role in cavity growth. When a high proportion of phase is present accommodation is almost complete and cavity nucleation is minimal.     

Separation of bacterial capsular and lipopolysaccharides by preparative electrophoresis

Preparative gel electrophoresis was used to separate and purify extracellular, capsular and lipopolysaccharides (EPSs, CPSs, and LPSs, respectively) from crude bacterial extracts. The procedure effectively separates CPS from LPSs. In addition discreet size ranges of these various polysaccharides can be isolated. The 'rough' (R-type), 'smooth' (S-type), and 'semi-smooth' LPSs were separated from one another. In addition different size classes of 'semi-smooth', or S-type LPS, can be separated. This procedure was demonstrated for diverse bacterial species, including the soil bacteria Rhizobium fredii, and the enteric bacterial species, Salmonella enteritidis and Proteus mirabilis. In the latter case, it was also possible to separate capsular polysaccharide from its lipid-bound form.     

Implications of the electromagnetic compatibility directive

The impact of the Electromagnetic Compatibility Directive on providers and users of electrical and electronic products is only starting to be appreciated by many of the very people who should by now have everything in place for 1st January 1996. This paper reviews the implications of the UK implementation of the Directive. All relevant products or systems supplied or brought into service from the end of 1995 are affected by the Directive, which must be complied with, otherwise serious criminal and civil penalties could result. The affixing of the CE-mark does not in itself assure adequate EMC performance of the product in each and every application     

Validity of two scoring systems for measuring cognitive development with the Rorschach.

Examined and compared the validity of H. Friedman's (see record 1953-03693-001) Developmental Level (DL) and J. E. Exner's (1974) Developmental Quality (DQ) as measures of cognitive development. Ss were 134 5–16 yr olds. Results support the convergent and discriminant validity of both DL and DQ, via their consistent relationships with age and various scores on the WISC-R. DL- and DQ-IQ relationships were affected by Verbal–Performance scale IQ discrepancies. Although DL and DQ were highly correlated with each other, they were most strongly related to different types of cognitive ability. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Collapse Behavior of Compacted Silty Clay in Suction-Monitored Oedometer Apparatus

This paper presents a methodology to investigate the collapse behavior of unsaturated soils using suction-monitored oedometer tests. By incorporating independent suction measurement, the oedometer apparatus is capable of following the same stress paths as in double oedometer tests, while continuously monitoring the suction. The proposed method has been used to investigate the collapse behavior of a compacted silty clay and to confirm the uniqueness of the loading-collapse surface as identified from loading and wetting paths. A new mathematical form of the yield surface within an elastoplastic framework is proposed on the basis of test results over a wide range of suctions (0 to 30,000?kPa) and net stresses (up to 7,000?kPa). The fundamental assumptions of the newer type of elastoplastic framework, which incorporate the degree of saturation within their stress variables, are evaluated, and the limitations of such models are identified. The collapse behavior of samples with different fabrics induced by differing compaction characteristics is also investigated within an elastoplastic framework. The difference in fabric, which is observed through a petrological microscope, can be presented in a quantitative way with different model parameters.     

Infra-red temperature measurement of bright metal strip using multiple reflection in a roll-strip wedge to enhance emissivity

In a continuous annealing furnace, strip temperature was measured using radiation thermometers aimed, at a shallow angle to the strip, into the wedge-shaped cavity formed between the strip and a roll. The dependence of the observed temperature on thermometer operating wavelength, field-of-view, aiming and polarisation was investigated. Comparison was made against reference temperatures taken with a surface pyrometer and also derived from strip metallurgy. Control of the furnace, using a wedge thermometer, was demonstrated. The technique is potentially applicable in a wide variety of bright metal processing furnaces.     

An experimental investigation of the superplastic forming behavior of a commercial al-bronze

The superplastic behavior of thermomechanically processed complex commercial Al-bronze (Cu-10Al-4.5Fe-6Ni-2Mn) sheet material has been investigated under biaxial bulge-forming conditions using constant gas pressures at different temperatures. The results of bulge testing were systematically analyzed usingm values determined from uniaxial tensile tests on the same sheet. The variations of dome height and thickness were examined relative to forming time. The rate of change of dome height was observed to be comparable to the corresponding apex strain rate, and both dome height and m value were seen to influence the thickness gradient. It was also demonstrated that the geometry of a dome was not constant during bulge formation. It could be flatter than, equivalent to, or sharper than a spherical shape. The grain size was relatively small (2 to 3 μm@#@) and very stable, and this is likely to be responsible for the large superplastic strains and relatively low levels of cavitation observed for the alloy. formerly with the Manchester Materials Science Centre formerly Visiting Scientist, Manchester Materials Science Centre