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Abstract  

Pichappan's formulation of the Discipline-Contribution Score (DCS) in the identification of core disciplinary journals is applied to social science literature. Modifications are made to Pichappan's method to cater for problems associated with low citation counts. Further analysis is undertaken to verify Pichappan's claims concerning the size-independent nature of the DCS score. The proposed modified formulation of the DCS calculation facilitates research into small research fields, and those characterised by low citation rates. The modified equation is tested on business and management literature.

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Summary A pseudo-isothermal method for the kinetic analysis was applied to the recrystallisation of a to ß nickel sulphide based on the Ozawa model for non-isothermal crystallisation in the presence of pre-existing nuclei. The aim of the analysis was to determine the number of steps involved in the recrystallisation and, hence, determine the applicability of the kinetic equation based on a single step mechanism, as is commonly applied in the kinetic analysis of solid-state processes using thermal methods. The kinetic analysis yielded evidence of at least two processes indicating that physical and mechanistic significance should not be drawn from the use of a single step approximation of the rate equation.

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Abstract  

Recent years have seen enormously increased interest in the comparative evaluation of research quality in the UK, with considerable resources devoted to ranking the output of academic institutions relative to one another at the sub-discipline level, and the disposition of even greater resources dependent on the outcome of this process. The preferred methodology has been that of traditional peer review, with expert groups of academics tasked to assess the relative worth of all research activity in ‘their’ field. Extension toinstitutional evaluation of a recently refined technique ofjournal ranking (Discipline Contribution Scoring) holds out the possibility of ‘automatic’ evaluation within a time-frame considerably less than would be required using methods based directly on citation counts within the corpus of academic work under review. This paper tests the feasibility of the technique in the sub-field of Business and Management Studies Research, producing rankings which are highly correlated with those generated by the much more complex and expensive direct peer review approach. More generally, the analysis also gives a rare opportunity directly to compare the equivalence of peer review bibliometric analysis over a whole sub-field of academic activity in a non-experimental setting.

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Summary A procedure for the extrapolation of accelerated thermo-oxidative ageing tests to lower temperatures is proposed. The procedure involves a deconvolution of the global process into high- and low-temperature components where the extrapolation to low temperatures is carried out using the low-temperature component. The method was tested on stabilized and unstabilized polyisoprene rubber and was found to produce realistic estimations of the length of the induction period of oxidation so giving a more accurate estimation of the service life. However, to obtain the low-temperature values of the adjustable kinetic parameters, very low heating rates are required (0.04 K min-1, 0.1 K min-1) making the measurement process time consuming. Using this method, more realistic estimates of the durability of a material are obtained.

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Abstract  

The DSC characterisation of the morphology of the metastable a phase of stoichiometric nickel sulphide was carried out using two calorimeters; a TA Instruments 2920 MDSC and a Perkin Elmer DSC-7, and two quenching histories. Based on these quenching histories, significant differences were observed in the heat flow curves, including the observation of a second exothermic peak which is tentatively assigned to be a metastable phase to metastable phase transformation. The kinetic constants for the a to b recrystallisation were determined as a function of degree of conversion using a mechanism free isoconversional model. Variations in the values of the kinetic constants were also ascribed to the quenching histories. Although the differences in morphology observed were ascribed to the processing history, the shift in the position of the a to b recrystallisation peak was partially attributed to the thermal resistances of the instruments used.

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Abstract  

A model developed for the estimation of the diffusion coefficient based on Fickian diffusion is applied to the dehydration of a Coober Pedy white play of colour (precious) opal using thermogravimetric analysis (TG). The model was originally applied to bulk and powdered opal (opal with no bulk). In this paper the opal was graded prior to TG analysis. The diffusion coefficient was calculated and is reported up to the critical point of water.

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Abstract  

The dehydration of samples of a Coober Pedy, South Australian sedimentary white opal, displaying play of colour, was investigated using TMA by heating the samples of the specimen to a range of temperatures between room temperature and 1000 at 200C intervals followed by cooling to room temperature. Etched fracture surfaces of the samples were then examined using SEM. The samples showed the typical expansion at low temperature up to 210C before contraction was observed. The contraction of the opals was ascribed to both sintering, supported by morphological change observed in the SEM micrographs, and dehydroxylation of the silanol groups producing silicon-oxygen-silicon bridges resulting in a more dense silica network.

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Abstract  

The dehydration of an opal specimen was investigated by thermogravimetric analysis (TG) in powder and bulk forms. The change in geometry resulted in a significant difference in the temperature range in which dehydration occurred with peak temperatures in the differential TG (DTG) curve for the hand ground opal at 203°C and for the bulk opal at 340°C. This difference was attributed to time taken for diffusion of free water in the bulk opal to the specimen surface prior to evolution as a registered mass loss. A model was proposed to account for the diffusion of water and was used to estimate the diffusion coefficient.

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Abstract  

Toughened glass panels used as a glazing material in multistorey buildings are known to fracture prematurely when they contain nickel sulfide inclusions as a result of the α-β phase recrystallisation in nickel sulfide. The kinetics of this recrystallisation were studied by differential scanning calorimetry (DSC) under isothermal and non-isothermal conditions. The recrystallisation was observed to be a two-step process with an induction period followed by the phase change. A two-stage kinetic model was used to estimate the recrystallisation time under ambient conditions. These values were found to correlate well with the observed time to failure for glass panels installed in multistorey buildings.

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