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In this study, a South African indigenous microalga Acutodesmus bajacalifornicus was evaluated in different cultivation media. Eleven potential cultivation media were identified and tested on A. bajacalifornicus, a potential source for biodiesel production. A. bajacalifornicus had the highest growth rate in the JG medium (in-house formulation), with a competitive average specific growth rate of 0.47 d−1. The highest biomass productivity was in the Hase medium, but with relatively low productivity of 53.1 mg.L−1.d−1. Analysis of the biomass lipid content and profile of each cell culture, using fatty acid methyl ester (FAME) gas chromatography (GC) showed that the lipid content varied between cultivation media, with minimum lipid content of 20% (w/w) and an average close to 47% (w/w). Utilising biodiesel property predictive formulas, and the lipid profiles obtained in this study, it was possible to predict the properties of biodiesel that could be generated from A. bajacalifornicus. It was found that biomass from eight of the media adhered to South African summer grade biodiesel standards. As such, A. bajacalifornicus is a potential candidate for microalgal biodiesel production in South Africa. However, the bioenergy yield rate would need to be improved to have a similar attractiveness to other studies.

Road pavements are constructed of bulk raw materials such as aggregate, cement, bitumen and water. The environmental, social, and economic impacts of the materials and processes should be quantified and monitored towards the optimisation of pavement design. At present, no such protocol is in place in South Africa. This paper proposes a framework for the development of a pavement life cycle assessment model, starting by documenting the life cycle inventory for bitumen, one of the leading environmental and social burdensome materials used for pavement development. This inventory acts as the first building block in the development of a life cycle assessment model by evaluating and delineating primary flows (inputs of materials and energy and outputs of pollution) related to the supply chain of bitumen in South Africa. The primary flows are represented by indicators which measure their quantitative impacts. The inventory provides impact category indicators for environmental and social related emissions, energy- and water-use and currently excludes other indicators such as emissions to water, waste generation, jobs creation and economic transformation, amongst others. These indicators are omitted due to lack of quality data at present and difficulty in the quantification of impacts, but recognition is given to their relevancy and importance. The approach is envisioned to function as the first version of a living protocol that will be improved on through further research. Although the primary target audience is South African road authorities, the approach can be adapted for use in any country.

Similar to the connected facility location problem, the passive optical network design problem requires the search for a subset of deployed distribution points ( splitters ) as well as an allocation of demand points ( optical network units ) to minimise deployment cost. In this paper we decompose a path-based relaxation of the problem using Benders as well as column generation and analyse strengthening cuts for the resulting master. Computational results for this approach are then illustrated.

We derive quadratic variation inequalities for discrete-time martingales, sub- and supermartingales in the measure-free setting of Riesz spaces. Our main result is a Riesz space analogue of Austinʼs sample function theorem, on convergence of the quadratic variation processes of martingales http://www.journals.elsevier.com/journal-of-mathematical-analysis-and-applications/ http://dx.doi.org/10.1016/j.jmaa.2013.08.037 National Research Foundation of South Africa (Grant specific unique reference number (UID) 85672) and by GNAMPA of Italy (U 2012/000574 20/07/2012 and U 2012/000388 09/05/2012)