The Lasentec focused beam reflectance measurement (FBRM) probe provides in situ particle characterisation over a wide range of suspension concentrations. This is a significant advantage over conventional instruments that require sampling and dilution. However, FBRM gives a chord distribution, rather than a conventional diameter distribution. Both theoretical and empirical methods for converting from chord to diameter data are available, but the empirical method was found to be more successful.

Biogas technology has the potential to provide benefits to three priority areas in Sub-Saharan Africa (SSA): energy supply, sanitation, and food security. Despite this, uptake of biogas systems has been slow and sporadic in the region. This review paper investigates what has prevented widespread dissemination of the technology in SSA by looking at the key barriers in the region, as well as identifying the main opportunities and the lessons that can be learned from successful biogas dissemination experiences in Rwanda, Tanzania, China, India, and Nepal. Installation costs, limited awareness and training for biogas users and insufficient follow-up services were recognised as being among the key barriers. SSA has favourable conditions for biogas technology, namely a suitable tropical climate in most parts of the region, a dominance of agricultural activities, and interest in alternatives to expensive conventional energy services. The region's favourable conditions therefore provide opportunities for increasing uptake of the technology. Experiences in other regions highlighted the importance of the government in supporting the biogas sector through suitable policies and incentives. Collaboration between research institutions, governmental departments, and biogas users, both current and future, was also recognised as being vital to improve the technology's dissemination and appropriate, long-term use.

A systematic approach for the synthesis of flexible and controllable plants is presented. It provides a new quantitative measure of the flexibility and controllability of a design and allows the designer to systematically evaluate different process structures and/or control systems. An integrated approach based on the dynamic mired-integer nonlinear-programmingproblem is introduced that consists of two stages in each iteration of the algorithm. In this way, the effect of disturbances on the process design and operation, as well as its ideal performance, under a variety of control schemes can be estimated. The method is illustrated using a mini-integrated plant as a case study.

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