Browsing by Author "Msuya, Neema"

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    Assessment of impact on forestation as a result of charcoal to gas switchover: the case of Dar es Salaam
    (University of Dar es Salaam, 2010) Msuya, Neema
    Tanzania has experienced a loss of forest cover of over 10.5 million hectares in just over 37 years (1961 to 1998). Part of this is due to charcoal production and use while the other part is due to other wood forest products like furniture, electric poles and building materials. This study was based on charcoal production and use data obtained from various stakeholders and literature. An ecological model was then developed using STELLA software to establish ecological relationship between charcoal use and forest cover loss. A cost benefit analysis was done to establish the true cost of using charcoal and the monetary, environmental and social benefits of the switch. Findings suggest that, the current charcoal consumption results in forest loss of about 105,000 ha per year. Projections show that forest loss will be about 3.0 million ha between 2010 and 2030, while emissions to the environment will be 49 million tonnes of CO2, 12 million tonnes of CH4, 1.0 million tonnes of SO2 and 9 million tonnes of NOx. Reduction in forest cover leads into reduced carbon sink. Sulphur and nitrogen oxides will lead into acid rain thus affecting agriculture.Shifting will lead to an annual household savings of about Tsh. 208 billion based on Liquefied Petroleum Gas (LPG) cost or Tsh. 284 billion based on Compressed Natural Gas (CNG) and the government is likely to earn a Tsh. 218 billion, in terms of value added taxes. It is concluded that, it is cheaper to use gas than charcoal in all aspects (social, environmental and economical). The biggest bottleneck in the switchover efforts is the purchasing power of the targeted group. The study recommends that, government should facilitate access funding of switchover initiative to cater for initial investment cost of about Tsh. 92.0 billion.
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    Production of poly (lactic acid) (PLA) from sisal waste
    (University of Dar es Salaam, 2018) Msuya, Neema
    This study aimed at producing polylactic acid (PLA) from sisal waste because of its abundance and the need to address sisal waste management as well as limited products from the sisal plant that lead to low income in sisal industry. Environmental problems resulting from petrochemical based plastics (non-biodegradability, depletion, and increased consumption) and need for alternative raw material for Lactic acid (LA) production were also the basis for this study. There have so far been few or no studies on sisal boles to produce LA or PLA. A full factorial design was used to design the experiments and to evaluate the effects of temperature (60-100ºC), pH (1-5) and time (30-60 minutes) on sugar yield during hydrolysis; effects of initial sugar concentration (120-160 g/L), temperature (37-43ºC) and pH (5-6) on LA concentration, yield and productivity; effects of temperature (43-47ºC) and time (15-25 minutes) on LA concentration using modified hybrid short path evaporation system (M-HSPE) and effects of temperature (160-180ºC), time (1-2 hrs) and tin octoate catalyst concentration (0.025-0.05%) on the PLA yield during polymerization. Lactobacillus delbrueckii sp. delbrueckii was used in the fermentation process to produce LA. Developed juice extraction method produced 791±0.6 ml of juice per kg of sisal bole. Maximum production of LA was 24.2 ±0.02 g/L and a yield of 93%, which occurred at a temperature of 37ºC, initial pH of 6 and initial concentration of 120 g/L. It was possible to produce 0.73±0.05 g of lactide per g of sisal bole LA used. Almost 99% conversion of lactide into PLA was done for 2 hrs when the system temperature was 180ºC regardless of the catalyst ratio used. The current findings support sisal boles juice as an alternative feedstock for LA production, a precursor for PLA. This will protect environment by using waste and it is an opportunity to participate in a global move to ban the use of petrochemical plastics in packaging.