Browsing by Author "Makunza, John K."
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Item Analyses of Deteriorating Old Masonry Buildings; Characterisation of Materials for Establishment of their Compatible Repairs(2015) Makunza, John K.; Kumaran, Senthil G.Most of the Governmental and religious building structures in Rungwe district are masonry structures built during the German East Africa period. These structures are deteriorating despite of various efforts on their repair intervention using modern cements and paints. This paper studies the types of mineral binders used, composition and physical characteristics of these in-situ mortar materials for the purpose of deciding on their appropriate compatible repair materials. Field observations and investigations, laboratory materials testing and review of the literature showed that the in-situ mortar materials constituted of sub-hydraulic lime mineral binders to natural sand (1:3) mortars. Currently there are no producers of hydraulic lime in Africa and a limited production worldwide. Mix design and analysis of locally available hydrated lime plus pozzolana natural sand (1:3) mortar material have shown compatibility in chemical and major physical properties and characteristics with the substrate in-situ hardened sub-hydraulic masonry mortars. Therefore use of these repair mortars is recommended for compatible repairs to these masonry structures and as a regional alternative to cement based materials for low rise masonry structures.Item Infrastructural Development in Africa by Use of Suitable Construction Approaches(2013) Msinjili, Nsesheye S.; Makunza, John K.; Akindahunsi, Akindehinde A.The construction sector generally shows a great contribution to socio-economic development in Africa, and has particularly enhanced the continent’s employment sector over the last few years. The African concrete construction sector is quite different when compared to its European and/or American counterparts. Modern infrastructural development exists in many urban cities in Africa, but this is at variance with rural areas, which tend to have little or no basic amenities such as sound road networks, solid and affordable shelter, and potable water. A large percentage of the construction activities are observed through the informal construction sector which mainly constitutes of cheap labour. This paper gives a basic introduction into the necessities for infrastructural development in Africa with focus on the construction sector. The paper addresses the practised construction activities based on the informal construction sector as well as suggests sustainable construction approaches sufficient for the African rural communities to benefit from the available economy. A better understanding of this sector is required which can help improve the existing methods of construction rather than adopt the construction techniques observed from the developed countries.Item A Kinetic Study of Anaerobic Biodegradation of Food and Fruit Residues during Biogas Generation Using Initial Rate Method(Scientific Research, 2013) William, Wanasolo; Manyele, Samwel V.; Makunza, John K.A kinetic study of biogas production from Urban Solid Waste (USW) generated in Dar es Salaam city (Tanzania) is presented. An experimental bioreactor simulating mesophilic conditions of most USW landfills was developed. The goal of the study was to generate the kinetic order of reaction with respect to biodegradable organic waste and use it to model biogas production from food residues mixed with fruit waste. Anaerobic biodegradation was employed under temperature range of 28˚C - 38˚C. The main controls were leachate recirculation and pH adjustments to minimize acid inhibitory effects and accelerate waste biodegradation. The experimental setup was comprised of three sets of bioreactors. A biodegradation rate law in differential form was proposed and the numerical values of kinetic order and rate constant were determined using initial rate method as 0.994 and 0.3093 mol0.006·day−1, respectively. Results obtained were con-sistent with that found in literature and model predictions were in reasonable agreement with experimental data.Item Regression Modeling and Analysis of Factor-Interactive Effect on Anaerobic Biodegradation Process for Biogas Generation(2014) William, Wanasolo; Manyele, Samwel V.; Makunza, John K.In this study, regression modeling and analysis of factor-interactive effect on anaerobic biodegradation process (ABP) of food residues mixed with fruit-waste is presented. An experimental anaerobic digester simulating mesophilic conditions of most urban solid waste dumpsites was developed. The goal was to carry out regression modeling on anaerobic biodegradation process for biogas generation. The main-and interactive-effects of initial-pH, ash-loading and leachate-level were investigated. Response surface methodology with miscellaneous 3-level factorial design was employed. A second-order polynomial regression equation was generated that predicted biogas generation rate (BGR). Results indicated that within the experimental range of factors applied there was a single factor significant effect of initial-pH and ash-loading on ABP while leachate-level single effect was observed to be insignificant (α < 0.05). The two factor interactive-effects of initial-pH/ash-loading and leachate-level/ash-loading were found to be significant while that of initial-pH/leachate-level interactions was not significant. Verification tests yielded maximum BGR values that were in good agreement with predicted values thereby validating the regression model.