Masters Dissertations

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A-study of capacity utilization of ict infrastructure in service oriented government organizations
(University of Dar es Salaam, 2010) William, Renath Massunde
Many service oriented government organizations have recently deployed Information and Communication Technology (ICT) infrastructure of different kind and of different capacities. Despite of all these efforts to reflect the major shift in management practices as seen in the commercial world, it has only tended to involve the automation of the existing manual procedures based on the movement of paper. The survey have been conducted in government ministries, departments and public organizations by means of interviews and questionnaires which have focus on collection of information to determine the type and capacity of available ICT infrastructure and how to facilitate the improvement of efficiency and effectiveness in government organizations by sharing existing ICT infrastructure to provide better services to the citizens of Tanzania. The finding of the study shows that there is non-government organization with ICT infrastructure that fully satisfies its demands and thus supports others! There are only few small ICT infrastructure implemented according to the vision and mission of their intended organization. Despite the remarkable advances in ICT, many organizations in Tanzania especially those that are purely service oriented have not fully utilized this technology. There are few ICT infrastructures available apart from desktop computers, which are found in almost every government offices. Integration of process and implementation of networking (LAN, WAN) is in disarray, location of technical expertise is not known, and information sharing process is poor among government departments.
Accelerating electricity access to rural areas in Tanzania: survey of rural electrification with renewable energy sources as an option for grid extension: the case of rural areas in Singida Region
(University of Dar es Salaam, 2009) Mgwira, Seleman Kastory
It is estimated that two billion people in developing countries in rural areas still lack access to electricity services, some of these people may be served by connections in the long run, but nonetheless, large number will remain unconnected because of the high costs of grid extensions in rural areas. In Tanzania only 1% of the rural population has access to electricity. Extending the grid to many parts of Tanzania is not economically viable and, in some cases, not practically possible, it is, therefore, quite clear that there is an urgent need of exploring other energy sources for rural electrification as option for grid extension. This research investigated rural electrification which renewable energy resources as an option for grid extension, Renewable energy source include solar, biomass, photovoltaic (Pv) geothermal and windmills. The study aimed at findings out the key determining factors for success in rural electrification with renewable energy sources in Tanzania for determining factors were identified, namely awareness on renewable energy technologies. Government subsidies, establishment of institutional framework and involvement of rural community in promoting rural electrification with renewable energy sources. The research was conducted in six villages in Singida region and also in Dar es Salaam region. The survey approach was used to collect quantitative data through simple random sampling. The sample of 180 was estimated, but only 151 returned this questionnaires. The data was analyzed using SPSS, and the results showed that government subsidies were the higher contribution of access in rural electrification with renewable energy sources. Also building awareness on renewable energy technologies and involvement of rural community were found to be important aspect for success of rural electrification with renewable energy sources.
Acceptability of public private partnerships in road infrastructure investment in Tanzania
(University of Dar es Salaam, 2017) Kiswaga, John Mgendela Peter
Meagre finances associated with inefficient resource allocation, contribute to the poor state of infrastructure in Tanzania, particularly road infrastructure. This road infrastructure dilemma results to unfulfilled end-user basic needs thus impeding development. The government of Tanzania, like many other developing countries in the world, has identified Public Private Partnerships (PPPs) as an alternative solution for addressing the state of inadequate road infrastructure resulting from insufficient government resources. The establishment of a PPP implementation framework in 2009 underpins the government’s desire. This research explored the Acceptability of the PPP model in road infrastructure investment in Tanzania now that there is an established PPP implementation framework. A total of 107 experts involved in infrastructure development, specifically road infrastructure from 19 entities (public and private) were purposively interviewed on the research topic by using a structured questionnaire. Exploratory Factor Analysis (EFA) was conducted using the Statistical Package for the Social Sciences (SPSS) and the factors with high scores in EFA were subjected to Confirmatory Factor Analysis (CFA) using the Analysis of Moment Structures (AMOS), a regression model tool that uses Structural Equation Modelling (SEM). Generally, it has been established that the PPP model of infrastructure delivery is acceptable in developing road infrastructure in Tanzania. However, it is critical for the government to pursue advocacy programs aimed at sensitizing the relevant stakeholders on the PPP framework if the government needs to realize the objective of fully engaging the private sector to deliver road infrastructure projects in a PPP setup.
Access to and use of Information and Communication Technology (ICT) in the Tanzanian Construction Industry: Case Study of Local Contractors/ Consultants in Dar Es Salaam
(University of Dar es Salaam, 2006) Kifanyi, Gislar Edgar
Information and communication Technology (ICT) introduces opportunities for improving communication to enhance effectiveness of many construction processes as well as creating new opportunities. The research aimed to determine access to and use of ICT in Tanzanian construction industry. The research based on medium class local contractors and consultants in Dar es salaam. Data for the research was collected data through a survey of randomly selected construction enterprises. A total of 38 valid replies were received, representing a response rate of about 51 percent. Out of which 24 contractors and 14 consultants were surveyed. The research has revealed that level of access to and use of ICT in Tanzanian construction industry is relatively low; however, the industry is at least starting to use ICT. The use of available ICT facilities is highly restricted to most commonly known information activities and it has not gone further to advanced use of technologies like LAN. WAN. Internet and World Wide Web (WWW). Further more the extent of ICT applications among contractors/consultants in Tanzanian construction industry in most of the core business processes is relatively low. General administration and supporting areas are among the business processes that are highly computerized .There is a growing gap in managing ICT where, high investment and expenditure on hardware and software on hand is coupled with poor human resource development on the other hand. From a strategic point of view, Tanzanian construction industry is still in a reactive mode of ICT management and the industry shows a limited understanding of the value and potential of ICT. The main factor that hinder access to and use of ICT in the industry are lack of ICT skills development and training, lack of funding and finance, lack of companies; ICT policy, lack of awareness of available ICT, rapid changes in technology, Integration/compatibility problems, poor ICT infrastructure and telecommunication systems. The research also suggests a need to aggressively push relevant government initiatives that would increase strategic use and adoption of ICT. Government and public agencies should consider policies that encourage the use of ICT in the construction industry thus making this industry sector more competitive.
Accessibility of financial resources to small contractors a case study of Dar es Salaam contractors
(University of Dar es Salaam, 2014) Kasambula, Geoffrey Raymond
In Tanzania most contractors in the lowest classes of registration lack adequate capital which would otherwise enable them go for large and lucrative works within their class limit. This study examines the criteria used by the commercial banks to evaluate small contractors’ loans applications. Specifically, the study looks at the eligibility of small contractors to access such loans and the common weaknesses hindering the access of credit for the group. A quantitative method was adopted for two different sample populations; commercial banks officers and small contractors (class VI and VII). Data were collected by questionnaires to all registered commercial banks in Tanzania and by telephone interview for the registered small contractors that are based in Dar es Salaam. Results established that small contractors’ loan repayment ability depend on their clients, and so bankers would often consider the borrowers’ clients when deciding issue of loans. It was further established that the banks would only consider loan applications of small contractors who have audited financial statements, clear purpose of the loan and bank’s knowledge of the small contractors business. However the contractors are only comfortable with the audited financial statement criterion. The information gathered by bankers about small contractors business may greatly help the banker in assessing risk associated with lending proposals. It was therefore established that commercial banks offer credit up to 14% of applications of small contractors.
Achieving residential urban water supply efficiency: an assessment of water demand management and water conservation practices the case of Mumbwa district, Zambia
(University of Dar es Salaam, 2015) Mwene, Siwa Irene
Access to sufficient amount of domestic water supply is one of the main challenges facing the people of Mumbwa District in Central Zambia and residential water demand is imperative in the implementation of Water Demand Management interventions. The purpose of the study was to access water demand and conservation practices among domestic users, by investigating the water supply status quo, domestic water use patterns and existing water demand and /or conservation practices that where in use within the District. Domestic customers’ surveys were conducted through distribution of questionnaires for the low, medium and high cost residential areas and an interview with the senior management from the Water Supply service provider in Mumbwa was done. The descriptive data analysis was done using the Statistical Package for Social Sciences (SPSS, 2007 version 16.0) for quantitative data. Secondary Data was retrieved from various literatures and from water service provider’s Management Information System database. Findings included; Water supply exceeding water demand, Non-Revenue water was found to be around 60%, Metered customers paid more than those on fixed tariff, 45% of the correspondents preferred retrofitting at property owners cost while Public awareness and education was limited to tariff adjustment meetings. For residential water use to be efficient the following recommendations were made; - Public education and awareness campaigns on wise water habits, retrofitting, water reuse and leakage repairs, Incentives for prudent water use by consumers, Policy guideline on Water Demand Management and implementation thereof and Staff capacity building.
Adaptation to the impacts of evaporationon hydropower generation at nyumba ya Mungu reservoir- Pangani basin
(University of Dar es Salaam, 2016) Shao, Magdalena Edes
The traditional and major source of electricity in Tanzania is hydropower. The generation of electricity in Tanzania is mainly from both hydro and thermal power plants. The total installed capacity on the interconnected grid is about 757 MW of which 555 MW (73%) is hydro and the rest is thermal. The projected evaporation was also estimated by Thornthwaite method which used the projected temperature obtained from the SWAT Database and the average annual evaporation obtained was 1699.33 mm. As compared with the current evaporation, there will be an increase of 6.86% of evaporation in coming 30 years. From the estimation of the impacts of evaporation done by Mikehydro, it was obtained that the expected power to be produced in the future under the influence of evaporation will decrease by 28.36%. Since evaporation cause the water loss from the reservoir and affect the power generation, and then there are several adaptation measures that have been proposed to be put in place so as to prevent water loss by evaporation and ensure maximum power generation. The proposed methods are as follows; Addition of aquatic plants, reduction of the exposed water surface, wind breakers, cover method, installation of trellis, as well treatment of water with Chemical Water Evapo-Retarders (WER).
Adaptive anisotropic diffusion-driven model for denoising iris images
(University of Dar es Salaam, 2021-04) Kyando, Daniel Michael
Biometric recognition is the automatic recognition of individuals based on their physiological or behavioral characteristics. A variety of systems require reliable personal recognition schemes to confirm or determine the identity of an person requesting access or service. IRIS recognition refers to biometric systems used to recognize individuals based on their IRIS patterns. In the absence of robust denoising method, these systems are vulnerable to the inaccurate interpretation of the patterns and granting access or service to illegitimate users. The classical Perona-Malik model has attracted wide attention of scholars for its ability to restore corrupted images while preserving useful details (edges and contours). Despite its notable achievements, this model requires manual tuning of the shape-defining diffusion coefficient to generate optimal results. Consequently, the tuning process, which suffers from inconvenience and time-ineffectiveness limits the model in time sensitive application like interpreting the IRIS patterns. Therefore, this work presents a method to adaptively update the value of the shape-defining diffusion coefficient in relation to the noise statistics in the IRIS image. Through a series of experiments, it was observed that the coefficient strongly correlates with the noise statistics in the IRIS image. Therefore, a relationship to describe the correlation was established and encapsulated into the evolutionary polynomial of order two. The polynomial was fitted from running 39 million iterations to generate two-dimensional space R^(K×σ) that contains K and σ variables. Least Absolute Residuals (LAR) is used to approximate the constants. The constants were α=0.00473,β=2.134,and γ=-0.3696 with 95% confidence boundary. The proposed diffusion function was further tested in removing noise in the IRIS images. It generated visually appealing denoized images with higher information content. It sharpens the edges and distinguishes them clearly from homogeneous image a region which is crucial in identification of texture patterns in IRIS images.
Adaptive controller design and sizing of battery energy storage system for enhancement of stability of an Islanded Solar photovoltaic systems
(University of Dar es salaam, 2020) Kisinga, Daniel Angelo
In this era where the world is faced with many challenges related to clean energy, Solar Photovoltaics SPV) system provide alternative source of energy which is cheaper and readily available. However, the intermittency nature of the solar power affects the voltage and frequency stability of the SPV system. To account for the effect, Energy Storage System (ESS) can be used under suitable control mechanism to stabilize the SPV system. Among different types of ESS, Battery Energy Storage System (Bess) offers a rapid response and therefore, suitable for voltage and frequency stability studies in this dissertation, an islanded SPV system was investigated, the BESS was sized based on compensation of the Direct Current (DC) link voltage and a Sinusoidal Pulse Width Modulation (SPWM) adaptive controller was designed under Voltage Frequency (VF) control strategy. Hill Climbing Maximum Power Point Tracking (HC-MPPPT) algorithm with boost converter was used to track the Maximum Power Point (MPP) of the SPV system. The H-bridge Single phase inventor was used for DC-AC conversion, while a Buck-Boost converter was implemented for charging and discharging the BESS. The system was modeled in MATLAB/ Simulink environment and voltage and frequency stability studies were performed. Under VF control strategy with the SPWM adaptive controller, the abrupt changes in solar insolation and variations of the load. The SPWM adaptive controller showed fast response with capability to maintain the voltage and frequency with the standard desired values compared to the conventional Pulse Width Modulation (PWM) controller.
Addressing security problems of computer network services: the case of University of Dar es Salaam network
(University of Dar es Salaam, 2009) Livingstone, Danny
Use of information technology is essential to most enterprises today and information security is now critical. User authentication, access control and the control of malicious logics is essential in service-oriented computer networks to identify and reject any unauthorized or suspicious network access. This work has concentrated on improvement of computer network security posture of UDSM as a case study. It consists of a comprehensive literature review on network security, which serves as a foundation of the research. The current security measures have been analysed based on ISO 17799. The data gathering instruments used was questionnaire with multiple choice questions, open-ended questions, and interviews to some selected respondents. Findings show that malicious software (malware) is the severe problem which the UDSM network suffers from. The study shows that users are aware of the danger imposed by malware; however, the weakness is on the control of their introduction into systems. Also Bad/Inadequate security practices resulted mainly from lack of clarity over ICT security responsibilities to users, IT staff and management. Thus, results of this study suggest that most of the good-to-have security practices as suggested by ISO 17799 are not part and parcel of day to day UDSM network security practices. It is therefore necessary that ICT security policy, access control procedures and communications and operations management be observed and where necessary be revisited and necessary amendments made to minimize security risks to an acceptable level. Given the observed problems, measures have been proposed in the dissertation to address the problems and improve the security posture of the UDSM network.
Adoption of e-commerce technologies in Tanzania shipping industry
(University of Dar es Salaam, 2013) Pasape, Godfrey
This study was done to assess adoption of electronic commerce technologies in Tanzania Shipping industry. It was as cross sectional study which used a closed ended questionnaire for data collection. Data was collected from among five shipping line and one clearing and forwarding company. The analysis was done to find out patterns and frequency distribution that show the extent of E- commerce adoption and application. Findings revealed that stakeholders in shipping industry were influenced by the following factors in their order of importance, infrastructure, social culture, government policy and government support, and socio economic issues. Additionally, the integration of electronic tools in port services reflects strong influence of e-commerce on the shipping industry performance. Based on the perspective of business firms operating in Dar es salaam Port, large and international firm are likely to engage in e commerce more when compared to small or medium local companies. The adoption and use of e- commerce was however independent of the capital based of the company. This is reflected by the fact that there were companies with reasonable capital but did not get involved in e- commerce while there where those companies with limited source of income involved in e-commerce. Most of the company have not fully integrated e-commerce in their business and if majority are just linked to only their business partners. The study concludes that E-commerce influences business performance and that this potential has not been taped by the majority of the firms in Tanzania. Thus appropriate knowledge on the benefits of e-commerce need to be disseminated alongside setting conducive environment to facilitate the adoption
Adoption of rainwater harvesting among the rural poor: a case of the semi-arid Mwala district, Kenya
(University of Dar es Salaam, 2013) Mwikali, Kiamba Pauline
Water availability is one of the major constraints to food production in many parts of Kenya, necessitating innovative and sustainable solutions to improved water harvesting, storage and management for agricultural purposes. The study looked into the existing technologies in Mwala District of Machakos County. Data for the study was acquired through questionnaires, semi-structured interviews, field observations and key informant interviews. The findings show that there is a wide variety of run-off based rainwater harvesting (RWH) technologies in the study area, such as communal earth dams and sand dams, individually owned underground tanks, water pans and polythene-lined ponds. A bivariate analysis done using the Statistical Package for Social Scientists (SPSS) indicated that adoption of these technologies is influenced by factors such as social, financial, human and physical capital. Failure of past RWH projects deterred farmers from investing RWH. An economic analysis for a 300m3 pond used to irrigate a 0.1ha farm of tomatoes with a 90 day growing period, showed high net present worth (US $ 76,059.17), indicating that it is a viable investment. Limitations to adoption include skepticism, the risk-averse nature of farmers, financial dependence and lack of information as to the existence of financing opportunities through microfinance institutions (MFIs). Opportunities for livelihood improvement through RWH in the study area include large sizes of land holdings, presence and engagement of NGOs in RWH projects through skills training, existence of (MFIs) with loan and credit packages with flexible terms for repayment, and high returns from growing of high value crops. These opportunities, if embraced and RWH taken up from the view point of a business venture, have significant potential in improving the livelihoods of members of the community.
Adsorption of maleic and oxalic acids on activated carbon prepared from tamarind seeds and cassava peels
(University of Dar es Salaam, 2013) Foya, Huruma
This study reports an investigation on the adsorption of maleic and oxalic acids onto activated carbons prepared from tamarind seeds and cassava peels by chemical and physical activation methods. This is because the adsorptive properties of activated carbon as reported in the literature depend on activation conditions, the nature of precursor and adsorbate. The activated carbons were characterized by iodine number, Attenuated Total Internal Reflectance Infrared (ATR-FTIR) and pH. Equilibrium studies of maleic and oxalic acids were conducted (room temperature, adsorbent dosage = 0.1 g and natural pH of solution) by batch adsorption method. The chemically activated carbons prepared at 400 to 800 oC had iodine number (445.5 to 1117.6 mg/g) while activated carbons prepared by physical activation method at 700 to 900 oC had iodine number (202.0 to 632.0 mg/g). The ATR-FTIR analysis of the prepared activated carbons mostly showed peaks for lactone (1739 cm-1), aromatic ring vibrations (1568 – 1504 cm-1) and pyrones structures (1433 – 1366 cm-1). The maximum adsorption efficiencies were 86.5 and 94.3 % at room temperature (26 ± 2 oC) for maleic and oxalic acids, respectively. The adsorption processes of maleic and oxalic acids could be well described by pseudo-second order kinetic model with correlation coefficient greater than 0.975 indicating chemisorption processes. The adsorption of maleic and oxalic acids on tamarind seeds and cassava peels activated carbons were best described by Langmuir and Freundlich isotherms, respectively. The maximum monolayer adsorption capacities of oxalic acid were 91.77 and 420.12 mg/g for cassava peels and decorticated tamarind seeds activated carbons, respectively. The maximum monolayer adsorption capacities of maleic acid were 305.60, 613.13 and 723.38 mg/g for tamarind seed testa, cassava peels and decorticated tamarind seeds activated carbons, respectively. The highest value of maximum monolayer adsorption capacity (723.38 mg/g) was higher than that reported in the literature (522.32 to 615.17 mg/g). This could be linked to the high basicity (pH = 9.55) and high adsorption potential in fine pores for a highly microporous activated carbon (iodine number = 632.0 mg/g). The adsorption process was favourable for all tested activated carbons as the Freundlich parameter (1/n) values were less than unity.
Agitation requirements for complete drawdown of floating solids on stirred tanks
(University of Dar es Salaam, 1989) Mmbaga, Joseph P
The agitation requirements for complete drawdown of floating solids in mechanically agitated tank vessels has been studied both theoretically and experimentally. A semi-theoretical equation has been derived on the basis of Kolmogoroff's theory of isotropic turbulence to determine the minimum impeller speed required for drawdown. The equation contains one adjustable parameter which has been found to be a function of the impeller type and position in the tank vessel. The equation was tested using various vessels and impeller configurations. The solid phase consisted of high density polyethylene (density = 897kg/m3), low density polyethylene (density = 840kg/m3) and cork material (density = 510kg/m3) with particle sizes ranging from 300um to 2200/um. The liquid phase consisted of water and aqueous solutions of zinc chloride in different concentrations so that the liquid density could be varied in the range 996kg/m3-1180kg/m3. The effect of impeller position and pumping direction has been extensively examined, as well as the use of non-conventional baffling systems to facilitate the drawdown of floating particles into the liquid. It was concluded that impeller clearance and pumping direction have a considerable influence over the minimum drawdown speed and its corresponding power consumption. A partial baffling system consisting of four half baffles has been found to have the lowest power requirements. Noticeable similarities exist between settling solids suspensions and floating solids drawdown, particularly for floating particles which, at rest, are almost completely immersed in the liquid. For cases different from this, the suspension of floating solids becomes a three phase system with entrapped air playing a significant role in particle drawdown. The proposed model works well within the experimental range covered (i.e. small density difference (<340kg/m3) and medium particle size (300 - 2500um) and can be used to predict the performance of floating solid-liquid systems.
Agriculture drought assessment using simulated soil moisture in Ruvu river basin
(University of Dar es Salaam, 2010) Twisa, Sekela
This research endeavored to assess agriculture drought using simulated soil moisture of Ruvu River Basin. Remote sensing data (Landsat images) of 1991 and 2000 and DEM of 90mx90m resolution were used. ILWIS and ArcView GIS software were used to process the remote sensing data. The Soil and Water Assessment Tool (SWAT) was used to simulate the long term hydrology of the basin. Flow and climatic data were collected and processed. The hydrologic model was calibrated for streamflow using an auto-calibration algorithm and validated over multiple years. The overall R2 for the calibration period was 0.42 and the validation period was 0.38. Overall, the model was calibrated, and the simulated streamflow compared well with the observed streamflow under varying land use scenarios, hydrologic and climatic conditions. Simulated soil moisture was analyzed using NDVI data. Analysis showed that the simulated soil moisture was well-correlated with NDVI. In the current study the drought index was compared with crop yield data. However, if crop yield data from individual farms is available, it could be used to develop a yield forecast model based on current drought conditions. Frequency and spatial characteristics of drought could be studied to develop an intensity-area-duration curve to characterize the spatial patterns of drought. This will help identify areas frequently affected by droughts and its spatial extent, which could be used for the development of a drought preparedness plan.
Air pollutants in the industrial sector in Tanzania
(University of Dar es Salaam, 2008) Kyando, Rose Michael
The study on the development of air pollution inventory for the industrial sector in Tanzania from 1995 to 2005 was done to estimate the key pollutants which are emitted during production processes. Pollutants were identified using the methodologies provided by Intergovernmental Panel on Climate Change (IPCC) for greenhouse gases (GHG) and Air Pollution Information Network for Africa (APINA) for non-greenhouse gases. Activities data were gathered from the Ministry of Industry, Trade and Marketing, National Bureau of Statistics. Other sets were from the Centre for Energy, Environment, Science and Technology (CEEST). The main pollution sources of Greenhouse gases (GHG) from this sector include cement production, metal production, alcohol beverages and solvent production. The gases considered were: NOx, CO2 CO, NMVOC, 502 and PM10. Generally, the results showed that the amount of emissions from this sector increased from year to year. Furthermore the percentage total annual emissions of CO2 from cement production topped the list with 90% contribution. It was followed by CO (7%), PM ° (2%), and 502 (1%), while NOx was almost zero. From this study, it can be concluded that the contribution of the industrial sector in the emissions of GHG or non-GHG is low compared to other sectors. Furthermore it is observed that the emissions trend was increasing annually and CO2 is the most significant pollutant.
Air pollutants in/ from waste management sector in Tanzania
(University of Dar es Salaam, 2008) Nkuwi, Imani Richard
This study was to study was to develop inventory for the key air pollutants (CH4, NOx, ), N20, CO and NH3) for ) and NH3) for Waste Management Sector in Tanzania from 1995 to 1 emissions for greenhouse for greenhouse gases and non-greenhouse gases were calculated Intergovernmental Panternmental Panel on Climate Change (IPCC) and Air Pollution )n Network for Africa (rk for Africa (APINA) guidelines respectively. Municipal solid d amount of wastewater `of wastewater were estimated using the population of the inventory e the emission from collision from clinical waste used primary data on amount of clinical lected at Muhimbili National hospital. Generally, the results showed that the if emissions estimated frcns estimated from these key pollutants in this sector increased with 1 1995 to 2005. For exan2005. For example emission of methane from solid waste disposal from 13.30Gg in 1995.30Gg in 1995 to 18.18Gg in 2005 which 36%. Methane from 1 wastewater rose from Ater rose from 1.55Gg in 1995 to 2.00Gg in 2005 which is 29%. ,xide from human sewage i human sewage increased from 1.18Gg in 1995 to 1.74 in 2005 which whereas NH3 from defecatF13 from defecation urination practices rose from 40.1Gg in 1995 to in 2005 which is 39%.TI-vhich is 39%.The emissions from incineration of clinical waste was ly for 2005 since managers since management method started in late 2004. The P11410 emitted 3-g followed by S02 (266qd by SO2 (266Gg), NOx (262Gg) and CO (24.9Gg). Thus, emissions ste management sector cement sector contribute to the pollution of the atmosphere but not nt to cause alarm. This stut alarm. This study may have uncertainty due to adoption of emission times from IPCC and AP ,m IPCC and APINA guidelines because (i) country-specific emission (ii) there is inadequate data for quantities of solid wastes are not available. (ii) The available and disposed of (iii) there(used of (iii) there is inadequate information on amount of waste water candled at disposal sites. disposal sites. .-refore recommended that commended that air pollution inventory should be done for the waste ment sector in Tanzania an, r in Tanzania annually so as to keep track of emission problems for decisions making. Further making. Further studies on country-specific emission factors, activity of waste managed should be done. This can minimize the level of d statistics of waste manage inties and hence in prove reliability in inventories. Prove reliance im xm
Analyses of deteriorating structural materials: characterisation for establishment of their compatible repairs: acase study of In-situ Materials in Masonry structures in rungwe district Tanzania
(University of Dar es Salaam, 2014) Mwakimi, Fadhili Simon
Observations show that historic mortar masonry structures in Rungwe district continue deteriorating despite of their frequently repair interventions done by the local Authority using modern cement materials. Establishment of characteristics of in-situ historic mortar materials that were used during construction of these masonry structures and their appropriate compatible repair materials are not yet done. This study has established these characteristics through both field and laboratory characterization techniques. Field characterization was achieved through observations, investigations and sampling, oral local interviews, consultations with the Local Government officials while laboratory characterization involved testing and investigations of both in-situ and repair mix designed mortar through chemical mineralogical, physical and mechanical analyses. Characterization was achieved through observations, investigations and sampling, oral local interviews, consultations with the Local Government officials while laboratory characterization involved testing and investigations of both in-situ and repair mix designed mortar through chemical, mineralogical, physical and mechanical analyses. Characterization revealed that in-situ mortar was composed of natural sub-hydraulic lime to sand (1:2 and 1:3) mortal mixes. Investigations on mix design of repair mortar revealed that a mix of Jambo hydrated lime added with latent pozzoanic sand both from Tukuyu Mbeya were compatible and appropriate for existing in-situ substrate materials in terms of chemical, physical and mechanical properties and therefore recommended for repairs to existing buildings and as a partial replacement of modern cement in mortar for construction of one to two story masonry buildings within the region.
Analysis and investigation of mini hydropower generation for zege village, Korogwe, Tanga
(University of Dar es Salaam, 2014) Kariwa, Lekamere Nicholaus
Zege village is located about 30 km Northeast of Korogwe district in Usambara Mountains, Tanga region. The remoteness of Zege village makes it difficult to be supplied with electricity from the national grid. A centralized mini-hydropower plant can therefore make a sustainable solution for Zege village electrification. The Zege village Mini-hydropower system plan is to be located at Kidabwa stream which crosses Zege village. The stream is un-gauged, therefore hydrological analysis for un-gauged stream was assessed by rainfall runoff method and the investigation of the mini hydropower at Kidabwa stream was done. The catchment area of Kidabwa stream is about 8.34 km2 with design flow of 240 l/s which is sufficient to run a 282.28 kW plant; the net head is approximated 149.87 m. The power demand of the village is about 620.9 kW, which is higher than the power expected to be produced at Kidabwa stream, Therefore it is important to look for other sources of the energy which can meet the village power demand, for example solar energy since sunshine in available throughout year at Zege village. The environmental and social impact assessment shows that the implementation of the proposed mini-hydropower plant will not cause any significant physical impacts in the environmental and social-economic activities at the area.
Analysis of a circulating fluidized bed medical waste incineration facility with air pollution control
(University of Dar es Salaam, 2010) Said, Mahir Mohammed
Circulating Fluidized Bed Incinerator is known to be one of the best available options for treating medical waste, particularly the pathological related waste. A proper operation of the incinerator is essential to ensure complete destruction of the waste. The combustion efficiency (one of the performance indicators) of the CFB incinerator is determined by the presence of carbon monoxide and carbon dioxide emission. In this regard, a study to investigate the relationship between variables affecting the combustion efficiency, namely temperatures, air pressure and air pollution control devices were performed using excel. Results showed that waste, combustion temperatures, air pressure and air pollution control devices contribute significantly to the combustion efficiency of the process. Two variables were used; inlet air flow rate and inlet liquid flow rate. The maximum and minimum liquid to gas ratio were between 1.9 l/m3 and 0.6 l/m3. The pressure was constant along riser. The maximum pressure drop of the CFB was 490 kPa. The combustion temperature was ranging between 700 and 970 , the constant temperature along the riser was observed when inlet air flow rate was 12 m/s. high temperature reduction was observed at heat exchanger from 350 to 90 . Approximately 75% of the flue gas heat energy was absorbed by cooling liquid; the maximum heat transfer in the heat exchanger was 60 kW. The pH of water used as scrubbing solution was changing from 6.68 to 5.57 and 6.88 to 5.72 for wet scrubber Stage 1 and 2 respectively, and the pH of 6 g/l lime concentration was changing from 12 to 6 for both stages. The combustion efficiency of the CFB with assistance of multistage wet scrubber was 99.6 %.

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