Browsing by Author "Wilson, Lugano"

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    Factors influencing energy use in urban transport sector: a case study of Dar es Salaam city.
    (1997) Wilson, Lugano
    The world witnessed energy crises of 1973/7 and that of 1978/79 bringing about escalating oil prices that was associated with curtailed supply. Despite the consequences of these crises, oil as a resource is bound to depletion. This creates the need for efficient utilization of this fossil fuel in all its applications. Furthermore, inefficient utilization of fossil fuel causes environmental degradation by emitting more greenhouse gases in the atmosphere with a result in global warming and thereby influencing climatic changes. World wide, the transport sector is a major user of energy demand, consuming over 16% (41 % for Tanzania). Energy saving in this sector may reduce this level. In determining the factors that influence energy use in the transport sector, a research was carried in the city of Dar es Salaam. Here, 61 questionnaires were distributed to vehicle users to investigate different factors such as vehicle makes and their proportions, distance traveled and fuel consumption per day, social aspects, vehicle operating costs, roads condition, drivers behaviour and maintenance aspects. These were corelated to fuel consumption patterns. Dar es Salaam city hosts unlimited list of vehicle makes from the world over, Japan being the major supplier. Reconditioned and used vehicles tools a larger percentage of total vehicle proportion which was mainly of saloon cars. Fuel consumption per day was recorded to be higher, being caused by poor operating environment of unworthy roads condition and inappropriate vehicle maintenance, Financial constraints was cited to be the contributor to this end. Along with the aforementioned physical factors that influence fuel consumption in urban transport sector there are social and management factors coming into effect. For instance, proper drivers' behaviour which comes second to vehicle technological improvement is potential in fuel saving. It is also observed that an effective way of reducing domestic fuel consumption or distance of travel is by improving public transport and introducing car pooling that works efficiently, this will marginalize the use of private transport. By managing transport demand and transport system many of the today's perceived transport problems could be overcome. Transport management starts from land use planning to as far as when transport projects are being executed and especially during the operation phase: Among the useful transport management techniques for alleviating road congestion includes improvement to road capacity, linking traffic signals, provision of one way streets, parking prohibition, controlling vehicle population, staggering working hours of activities and even by road pricing. While observing the discussion on social and management factors the following is recommended. The Government has to establish sound legislation on road worthiness of motor vehicles and there should be a governing body that will oversee the quality of imported vehicles. Roads condition improvement is necessary and should be maintained through timely repairs. Furthermore, the advent of Songo Songo natural gas in Southern Tanzania can reduce the country's dependence on using imported petroleum for application in internal combustion engines.
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    Investigation of the influence of moisture content on biomass conversion in high temperature air/steam gasification (HTAG) process
    (University of Dar es Salaam, 2013) Wilson, Lugano
    Though they are sustainable, biomass energy technologies are challenged by the varied biomass characteristics. This study invoked Gibbs equilibrium modelling and laboratory techniques to investigate characteristics of 15 types of Tanzania biomasses for application in the high temperature air/steam gasification (HTAG) process. The laboratory investigation findings showthat the biomasses’ elemental composition of oxygen ranged from 27.40-42.70% whereas that of carbon and hydrogen ranged from 35.60-56.90% and 4.50-7.50%, respectively. Akinetic study showed that with the exception of sunflower stalks, jatropha husks and sisal bole that exhibited zero order reaction mechanism, all other biomasses obeyed the first order. Biomasses with highest activation energy values were rice husks (935.33 kJ/mole), rice bran (1,023.45 kJ/mole), and palm shells (1,070.84 kJ/mole). The combined laboratory and modelling investigations revealed that moisture content above 20% degraded cold gasification efficiency of the HTAG process, which resulted in lowsyngas heating value, below 6 MJ/nm3. However, hydrogen content of the syngas increased with moisture (up to 40%) and steam injection. The positive effect of high temperature, above 900°C was to enhance syngas evolution ateach moisture level. Based on the findings of this study, the analyzed biomasses exhibited suitable elemental composition and performance characteristics for use in thermochemical processes like the HTAG. For an efficient biomass conversion in the gasification process, its proper harvesting, handling and storage of the biomass is recommended. A wider application of the gasification technology for converting the abundant tropical biomass to the needy energyis therefore envisaged.