Browsing by Author "Salisbury, Frances."

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An investigation into the application of multiple criteria decision analysis as a decision support tool for municipal engineers.
(2015) Salisbury, Frances.; Buckley, Christopher Andrew.; Brouckaert, Christopher John.
A Multiple Criteria Decision Analysis (MCDA) was developed for the selection of sanitation systems. This decision support system was aimed at assisting municipal engineers to design and implement sustainable solutions to meet the municipality’s obligation to provide Free Basic Sanitation (FBS). The literature review investigated the factors which determine the success of sanitation projects and the sustainability framework in which the MCDA would be structured. Different multiple criteria methods were investigated with particular reference to those which have been applied to sanitation. Multi-Attribute Value Theory (MAVT) was selected as the method most suited to the problem under consideration. This requires the selection of indicators for which alternatives can be evaluated as well as the development of a multi-attribute value function which aggregates the partial values assigned to the indicators to arrive at an overall value for each alternative. The implementation of FBS by the eThekwini Municipality and the research projects carried out by the University of KwaZulu-Natal on the sanitation systems used by the municipality were analysed. Data from this research informed the allocation of indicator values to the sanitation alternatives under consideration: initially Ventilated Improved Pit latrines (VIPs) and Urine Diversion Dehydrating Toilets (UDDTs). Later a third option, the pour-flush latrine, was added. Criteria which determine the sustainability of sanitation were selected and a spreadsheet-based MCDA with stakeholder and expert user interfaces was developed. Stakeholders will determine the weighting of each indicator and expert users will determine the values to be entered for the alternatives against each indicator. The partial values are aggregated using a weighted sum function. The MCDA was populated with values derived from the eThekwini research. Sensitivity analysis was carried out for the weighting of the three main criteria: environmental, financial/technological, and socio-cultural. An innovative scenario analysis method was used to determine the effect of different weightings and/or values. The MCDA was found to provide a guiding framework for municipal engineers in their efforts to implement sustainable sanitation. The process of deriving values for the MCDA is likely to prove even more useful than the overall value scores of the options under consideration.
A model of calcium and phosphorus growth in broilers.
(2022) Salisbury, Frances.; Gous, Robert Mervyn.
A model is a simplified representation of a system. It can be used to organise knowledge and to develop theory in an academic setting, but also for practical applications. This research sought to incorporate as much as possible of the theory of calcium and phosphorus in broiler chickens into a model. This would allow researchers to see where there are gaps in the theory and to suggest ways in which experiments might be designed to fill these. It is hoped that this model will provide a guide for producers when they feed broilers, particularly under changing conditions. Current tables of requirements reflect empirical data on bird performance, collected at a certain point in time. As genetic progress, welfare considerations and environmental pressures change the constraints on an animal production system, a dynamic model allows the nutritionist to be more responsive to these. The calcium/phosphorus model is located within an existing broiler model that simulates energy metabolism and protein growth. This model is linked to a feed formulation component and an optimiser that allows producers to manage their enterprise to meet production and profit targets. Because standardised digestibility values have proved elusive for minerals, a digestibility module assesses the complete feed and calculates mineral quantities available to the bird. These are then assessed against the requirements for soft tissue which is given priority and then bone growth. Excess mineral is excreted and this, and bone mineralisation are considered for the optimiser module of the main model. The model was calibrated and validated using two body composition studies. It was demonstrated that reasonable predictions of performance could be made, but that modelling digestibility is a critical component. Perhaps most importantly, the model maps a way forward for research targeted at filling the gaps in the body of knowledge. These have been shown to be surprisingly large: very little whole carcass body composition work has been done and few studies of calcium and phosphorus digestibility have been designed to allow modelling of their interactions.