Ghana

A strategic task for building research in the Ghanaian context should be to give new life to well-tried methods and to develop the local resources of labour and materials, writes the director of the Building and Road Research Institute at Kumasi. The reasons are not only economic - saving scarce foreign exchange - but social, by creating viable local industries. This article concentrates on the housing-related studies and reports a few projects which have tried to apply the concepts in a practical way.     

Effects of captan on the growth and cellulase production of Aspergillus aculeatus and Botryodiplodia theobromae

The effects of captan on the production of mycelia and cellulolytic enzymes of Aspergillus aculeatus and Botryodiplodia theobromae were investigated in culture. There was decrease in mycelia of both fungi with increase in captan concentration in ppm. No fungal growth was recorded at 400 ppm. Captan at 10–50 ppm at 25 and 30 °C induced both fungi to produce more mycelia than in control cultures. The effect of captan concentration on the production of cellulases showed a decrease in quantity with increase in concentration. At 400 ppm no cellulase was produced by both fungi. There was a general decrease in cellulase production with increase in temperature either in control or experimental cultures. In cultures incorporated with captan, the cellulolytic activities of A. aculeatus (at 10 ppm) and B. theobromae (at 10 ppm, 50 ppm) were found to be relatively high.     

Determination of the thermophysical properties of translucent materials

A method is proposed for determining the thermophysical properties of translucent scattering materials in the nonsteady heating regime.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 49, No. 6, pp. 977–982, December, 1985.     

Dynamics of nanosecond laser annealing of silicon

On the basis of a numerical solution of the Stefan problem, the dynamics of nanosecond laser annealing of silicon is investigated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 48, No. 2, pp. 306–312, February, 1985.     

Analytical approaches to characterising fish tainting potential of oil sands process waters.

A three-stage study has been carried out with rainbow trout (Oncorhyncus mykiss) to develop analytical approaches which can provide a fingerprint for tainting by oil sands chemicals from process-affected waters and natural sources. The objective was to find a simpler alternative to sensory evaluation. In the first stage, a set of seven test compounds was added to fish tissue which was analysed by headspace and solvent (dichloromethane, DCM) extraction followed by gas chromatography-mass spectrometry (GC-MS). In the second stage, fingerlings (5-20 g) were exposed for 96 hours to the test compound mixture at 1.0 and 0.5 times the estimated tainting threshold concentrations. In the final stage, fingerlings were exposed for 96 hours to an oil sands process water at 5, 10, 20 and 50% concentrations in clean water. None of the test compounds was identified in DCM extracts of tissue from exposed fish. Two long-chain aldehydes, hexadecanal and 9-octadecenal, were tentatively identified in these extracts by matching of mass spectra with library spectra.     

Multivariate statistical analysis of a high rate biofilm process treating kraft mill bleach plant effluent.

This study reports on a multivariate analysis of the moving bed biofilm reactor (MBBR) wastewater treatment system at a Canadian pulp mill. The modelling approach involved a data overview by principal component analysis (PCA) followed by partial least squares (PLS) modelling with the objective of explaining and predicting changes in the BOD output of the reactor. Over two years of data with 87 process measurements were used to build the models. Variables were collected from the MBBR control scheme as well as upstream in the bleach plant and in digestion. To account for process dynamics, a variable lagging approach was used for variables with significant temporal correlations. It was found that wood type pulped at the mill was a significant variable governing reactor performance. Other important variables included flow parameters, faults in the temperature or pH control of the reactor, and some potential indirect indicators of biomass activity (residual nitrogen and pH out). The most predictive model was found to have an RMSEP value of 606 kgBOD/d, representing a 14.5% average error. This was a good fit, given the measurement error of the BOD test. Overall, the statistical approach was effective in describing and predicting MBBR treatment performance.