Faculty of Engineering

Permanent URI for this communityhttp://localhost:4000/handle/20.500.12504/3

Browse

Now showing 1 - 20 of 138

Abating eutrophication on urban lakes: a case study of Kabaka's Lake, Uganda
(IWA Publishing Water Practice & Technology, 2023-07) Anne, Nakagiri; Abel, Mutyaba; Charles, Onyutha; Kenan, Okurut
Eutrophication of water bodies is a challenge in many urban areas. This study measured and modelled quantitatively the pollutant nutrient load of an urban lake (80,596 m2), and assessed both external (constructed wetland) and internal (dredging) eutrophication extenuation measures. For the past 25 years, there has been redistribution (p < 0.005) of the lake's catchment land use, with built-up area increasing by 78.5%, and a reduction in vegetated (37.2%) and water surface (1.8%) areas. A 92.2% reduction in the lakes receiving wetland footprint (p = 0.000003) was noted, with increased nutrient load. The lake's light attenuation was found to be dominated by algae, limited by nitrogen and classified under the oligotrophic class (Trophic State Index < 40), with a threat of eutrophication in an estimated 25 years. Scenario analyses show that the construction of a wetland in the remaining 0.54 hectares of natural wetland will reduce total phosphorus by 35% and total nitrate by 45% (p = 0.05), whereas dredging the lake could reduce them by 80% each (p = 0.0005). Watershed management is the only sustainable solution to control nutrient flow into the lake and enable self-cleansing, factoring in the design of the receiving wetland and groundwater sources.
Abating the effects of different land use activities on eutrophication of Kabaka’s lake Kampala - Uganda
(Kyambogo University, 2019-11) Mutyaba, Abel
Various land uses resulting from urbanization in Kampala the capital city of Uganda, have reduced the natural pollutant filtration value of the wetlands. This has in turn led to a decline in the water quality and gradual eutrophication of available water bodies such as Kabaka’s lake, characterised with green colored water, foul smells, and tastes. The aim of this study was to assess eutrophication management strategies for abatement of the effects of the different land use activities on natural water quality of Kabaka’s lake. The study focused on; classification of downloaded Landsat imagery for the last 25 years, mapping of pollution hotspots and nutrient distribution with GIS, and assessment of both external (constructed wetland) and internal (dredging) eutrophication extenuation measures. Following the research showed that Kabaka’s lake catchment land use has been significantly (p<0.005) been redistributed, with buildup area increasing by 78.5%, vegetated area reducing by 37.2% and water reducing by 1.8%. This has not only significantly reduced the lakes receiving wetland footprint by 92.2% (p=0.000003) but also increased the nutrient load in the catchment mainly from; garage oil spillages, car washing bays wastewater, and sewerage. The 80,596 m2 Lake’s light attenuation is currently algae dominate, limited by nitrogen and classified under oligotrophic class of lakes (Trophic State Index<40) with a threat of eutrophication in an estimate of 25 years. Construction of a wetland in the remaining 1.34 acres of natural wetland will significant reduce Total Phosphorus by 35% and Total Nitrate by 45% (p = 0.05), whereas dredging the lake will reduce both by 80% (p = 0.0005). Watershed and proper land use management, establishment of riparian buffer vegetation and a diversion channel and community sensitization were some of the study recommendations. Key words; Land use, Nutrient concentration, Eutrophication
An advanced continuum damage mechanics model for predicting the crack progress process based on the consideration of the influence of crack direction under quasi-static load
(Elsevier: International Journal of Mechanical Sciences., 2017-09) Yun, Kumchol; Wang, Zhenqing; Ronald, Sakaya; Pak, Yongchol
In reality the wrong crack path can be generally obtained in the case of arbitrary crack propagation by traditional continuum damage mechanics (CDM). In this paper a novel advanced continuum damage mechanics (ACDM) method is proposed, which can predict the crack propagation and fracture behavior correctly for the structures. The material property degradation method, which is usually used when simulating the structures within the framework of CDM, is advanced based on considering the influence of crack direction. The maximum tensile stress criterion is used to predict the damage initiation and crack propagation direction and the advanced CDM used to predict the damage evolution process in meso-level under the quasi-static load. It can directly evaluate the propagation process of the discrete crack and the fracture strength for structures using the continuum model as well as not using discontinuum model. The algorithm for the application of our advanced CDM theory in the numerical simulation based on finite element method (FEM) is presented. ACDM model is not only a simple and useful model which can easily be used in FEM framework but also a phenomenological model based on the concept of crack propagation. The simulation results by our ACDM are compared with the experiment results and the ones and from cohesive zone method and extended finite element method for good agreements to be achieved.
African food insecurity in a changing climate: the roles of science and policy
(Wiley Online Library: Food and Energy Security, 2018-12-12) Onyutha, Charles
African population is projected to double to 2.48 billion people by 2050. The population increase poses a serious challenge of increasing food supply to meet the future demand. This challenge is compounded by climate change impacts on agriculture. In this paper, how poverty contributes to household food insecurity is explored and measures suggested to help address this challenge. To plan adaptation measures, linkages among food insecurity, poverty, and illiteracy should be considered. For the sub-Saharan Africa (SSA), adaptation (focused on poverty alleviation) should be prioritized and preferred to mitigation. Enhancement of adaptive capacity should not only be tailored toward empowerment of women but also made highly localized to household levels. Generally, efforts could be geared toward yield gap closure, addressing challenges regarding food distribution, promoting non-farm income-generating activities, and unification of government priorities in agriculture and food security. Government in each country of the SSA should ensure that governance strongly embraces transparency, accountability, and integrity otherwise as it is said a fish rots from the head down. Estimates of uncertainty in predicting future climate and their implications on expenditure related to adaptation should to always be made in an integrated way and reported to support actionable policies. To increase credibility in climate prediction especially at local scales, advances toward improving climate models (for instance by refining spatiotemporal scales, enhancing models’ capacity to reproduce observed natural variability in key climatological variables like rainfall) should be made, and this requires support from the investment in climate science. Science–policy interfacing is required in planning and implementation of measures for adapting to climate change impacts. In summary, food insecurity and persistent poverty especially in the SSA should be of direct relevance and concern at a global scale. Thus, global collaboration in science is key to achieve food security in the SSA.
Amplification of compound hot-dry extremes and associated population exposure over East Africa
(Climatic Change, 2024-09-09) Ayugi, Brian Odhiambo; Onyutha, Charles; Zhu, Huanhuan; Babousmail, Hassen; Chung, Eun-Sung; Sian, Kenny Thiam Choy Lim Kam
Quantifying the vulnerability of population to multi-faceted climate change impacts on human well-being remains an urgent task. Recently, weather and climate extremes have evolved into bivariate events that heighten climate risks in unexpected ways. To investigate the potential impacts of climate extremes, this study analyzes the frequency, magnitude, and severity of observed and future compound hot-dry extremes (CHDEs) over East Africa. The CHDE events were computed from the observed precipitation and maximum temperature data of the Climatic Research Unit gridded Timeseries version five (CRU TS4.05) and outputs of climate models of Coupled Model Intercomparison Project Phase 6 (CMIP6). In addition, this study quantifies the population exposure to CHDE events based on future population density datasets under two Shared Socioeconomic Pathways (SSPs). Using the 75th/90th and 25th/10th percentile of precipitation and temperature as threshold to define severe and moderate events, the results show that the East African region experienced multiple moderate and severe CHDE events during the last twenty years. Based on a weighted multi-model ensemble, projections indicate that under the SSP5-8.5 scenario, the frequency of moderate CHDE will double, and severe CHDE will be 1.6 times that of baseline (i.e., an increase of 60%). Strong evidence of an upward trajectory is noted after 2080 for both moderate and severe CHDE. Southern parts of Tanzania and northeastern Kenya are likely to be the most affected, with all models agreeing (signal-to-noise ratio, SNR > 1), indicating a likely higher magnitude of change during the mid- and far-future. Consequentially, population exposure to these impacts is projected to increase by up to 60% for moderate and severe CHDEs in parts of southern Tanzania. Attribution analysis highlights that climate change is the primary driver of CHDE exposure under the two emission pathways. The current study underscores the urgent need to reduce CO2 emissions to prevent exceeding global warming thresholds and to develop regional adaptation measures.
Analyses of multi-decadal variability and trends in precipitation and potential evapo-transpiration across lake Kyoga basin
(Kyambogo University, 2020-10) Acayo Grace
The Lake Kyoga basin is located in Kyoga water management zone covering eleven sub-catchments in Uganda. The population in this region mainly depend on rain fed agriculture for their livelihood. However, recent changes in precipitation and climatic conditions calls understanding trends and variability of current and historical hydro-climatic variables. This study analyzed long-term trends and variability in precipitation and Potential Evapo-Transpiration (PETo) covering the period 1901 -1960 and 1961- 2015 respectively. Two periods were considered to remove the effect of step-jump in precipitation mean on analyses. For PETo, the period 1961-2008 was considered. Both trends and variability were assessed non-parametrically using the cumulative sum of rank difference approach. Possible drivers of variability in PETo and precipitation were sought in terms of the co-variation of the climatic variables with the large scale ocean-atmospheric interactions. The correlation of precipitation, potential Evapo-transpiration and climate indices were assessed. The climate indices included Atlantic Multi-Decadal Oscillation (AMO), North Atlantic Ocean (NAO), Indian Ocean Dipole (IOD) and Nino3. It was found that precipitation over the period 1901-1960 for the month of March, April, May (MAM) exhibited positive anomalies was not significant (p>0.05) implying wet condition, however, for September, October, November (SON) and annual time series exhibited negative anomalies. The annual variability in precipitation yielded negative anomalies around 1960s to 1970s while positive anomalies were exhibited around 1990s and 2000. Variability in annual precipitation at most locations was found to be insignificant (p>0.05). Trends in PETo were not coherent as those of precipitation.
Analyses of precipitation and evapotranspiration changes across the lake Kyoga basin in East Africa
(MDPI: Water, 2020-04-16) Onyutha, Charles; Acayo, Grace; Nyende, Jacob
This study analyzed changes in CenTrends gridded precipitation (1961–2015) and Potential Evapotranspiration (PET; 1961–2008) across the Lake Kyoga Basin (LKB). PET was computed from gridded temperature of the Princeton Global Forcings. Correlation between precipitation or PET and climate indices was analyzed. PET in the Eastern LKB exhibited an increase (p > 0.05). March–April–May precipitation decreased (p > 0.05) in most parts of the LKB. However, September–October–November (SON) precipitation generally exhibited a positive trend. Rates of increase in the SON precipitation were higher in the Eastern part where Mt. Elgon is located than at other locations. Record shows that Bududa district at the foot of Mt. Elgon experienced a total of 8, 5, and 6 landslides over the periods 1818–1959, 1960–2009, and 2010–2019, respectively. It is highly probable that these landslides have recently become more frequent than in the past due to the increasing precipitation. The largest amounts of variance in annual precipitation (38.9%) and PET (41.2%) were found to be explained by the Indian Ocean Dipole. These were followed by precipitation (17.9%) and PET (21.9%) variance explained by the Atlantic multidecadal oscillation, and North Atlantic oscillation, respectively. These findings are vital for predictive adaptation to the impacts of climate variability on water resources.
Analysis of the development and installations of renewable energy-based mini-grids: case study Uganda
(IEEE PES/IAS PowerAfrica, 2020-08) Cartland, Richard; Sendegeya, Al-Mas; Hakizi, Jean de Dieu Khan
The provision of energy to all citizens has been an outstanding need in most developing countries in order to meet Sustainable Development Goals (SDGs) by 2030. Uganda as a developing country has put mechanisms in place to provide electricity to her people and be able to realize the national vision of 2040 and be able to address other SDGs by 2030. Solar PV mini-grids are emerging as popular alternatives to address rural electrification shortfall after other renewable energy mini-grid types proved desirable for some period. Uganda's expectations of renewable mini-grids are high with the Ministry of Energy and Mineral Development, the World Bank, and the Government of Uganda showing much interest to support the mini-grid development. This paper, therefore, looks at general mini-grid development and operation models and finds out arguments making renewable energy mini-grids popular at the expense of non-renewable based mini-grids. The methodology focuses on exploring ideas and formulating a hypothesis by summarizing, categorizing, and interpreting both the primary and secondary data. The paper concludes looking at the strength, benefits, and challenges of renewable mini-grids.
Analyzing the factors that affect the quality of staircases: a case study of universities in the central region, Uganda
(Kyambogo University [unpublished work], 2023-10) khabusi, Mukhwana Benjamin
Staircases are the most common means of vertical access in low and medium rise storeyed buildings in Uganda. Their purpose is to provide safe means of movement from floor to floor. Reduction of accidents would be one of the functional requirements of stairs which is part and parcel of safety. However, the high accident rates are an indication of poorly designed and constructed stairs. With such problems on staircases, this study sought to investigate the factors that affect their quality in storeyed buildings in Ugandan universities specifically in the central region in a bid to minimize the occurrence accidents. Four kinds of surveys including observational, design and construction, technical and staircase user surveys were conducted in the study. The observational survey done using a check list revealed that the key features for quality vertitical access were; tactile ground indicators, balustrades, handrails, risers, treads, stair flights, newel posts, nosings, landings and presence of ramps in buildings. The design and construction survey which was done using self-admistered questionnaires involving 22 respondents revealed that the major factors that affect the quality of staircases were: design proficiency, construction competences, design review and other project factors. The technical survey conducted using a technical tool revealed that 66% of the stairs did not conform to the design and construction requirements due to riser heights, tread depths, slope relationship (2Rise + Going), stair slopes, handrail heights, handrail extensions and depth of nosing contrasts not conforming to the standards. The staircase user survey carried out using self-admistered questionnaires involving 212 respondents revealed that 26.3% of the users were injured while using the staircases due to missed steps, slippery surfaces, inadequate lighting in the stairwell, unevenness in the risers and treads and broken edges of steps. It was therefore concluded that to minimize the occurrence of accidents on staircases, proper design, construction and supervision need to be done in accordance with the standards short of which will lead to accidents. Key words: Staircase, quality, accidents, design, construction, supervision, user
Applicability of public private partnerships in development of infrastructure in higher institutions of learning in Uganda
(Kyambogo University (un published work), 2019-11) Mabonga, Sylvia Namakoye
Public Private Partnership system is considered an innovative finance strategy which offers good prospects for global construction industry. Yet, since the adoption of the system in Uganda, the benefits have not been fully realized. This research, therefore aimed at establishing the extent of use of the Public Private Partnerships, the question of continuity or and starting to use it, inspirations and barriers affecting its applicability in higher institutions of learning in Uganda. The study adopted a cross sectional survey research design, with both quantitative and qualitative approaches. With a sample size of 138 respondents that were purposively selected, regression and correlation analyses were performed to establish the significance of the bio-data and inspirations to show the determination to continuation of the PPP system. The survey results show that PPPs have only been embraced to a minimal extent of 4% in higher institutions of learning in Uganda. Further analysis showed there was interest to continue or start using PPPs. Inspirations were established as; availability of funds for development, completed within stipulated time, cost and transfer of all risk to the contracting party in fig. 4.12. Barriers were found as; PPPs projects are feared to be complex and risky, lack of expertise on establishing and managing projects, lack of legislation or compatibility with the existing procurement ordinances and lack of political support. This research can be impactful to policymakers to adopt when implementing future projects by use of a developed framework in fig. 4.15 that would offer solutions to the identified barriers. Key words: Barriers, Continuity, Development, Infrastructure, Inspirations, Public Private Partnerships.
Application of black soldier fly larvae in decentralized treatment of faecal sludge from pit latrines in informal settlements in Kampala city
(Frontiers in Environmental Science, 2023-02) Richard, Tokwaro; Swaib, Semiyaga; Charles, B. Niwagaba; Anne, Nakagiri; Jotham, Ivan Sempewo; Chimdi, Muoghalu; Musa, Manga
Introduction: Faecal sludge management (FSM) in urban areas of low-and middle-income countries (LMICs) is not properly implemented due to inaccessibility of sanitation facilities and high faecal sludge (FS) emptying costs, amongst others. Unlike in solid waste and fresh human excreta, use of black soldier fly larvae (BSFL) in treatment of FS from pit latrines - which are the most common sanitation facilities in urban areas of LMICs - has not yet been explored. Moreover, the optimal conditions for efficient FS degradation, such as moisture content, feeding rate and larval density are not yet well known. Against this backdrop, the overarching aim of this study was to determine the effectiveness of BSFL in treating FS under different conditions of moisture content, feeding rate and larval density. Also, the quality of residue left after treatment was assessed. Methods: FS samples were collected from lined and unlined pit latrines in Bwaise I parish in Kampala, Uganda and experiments were set up to feed 10-day old larvae. Results and Discussion: The optimum feeding rate, larval density and moisture content were found to be 50 mg/larvae/day, 1.33 larvae/cm2 and 60%, respectively. The reduction efficiency at optimum conditions were 72% and 66% for FS from lined and unlined pit latrines, respectively. It was further noted that BSFL can feed on FS from pit latrines without dewatering it, hence there is no need for a dewatering unit. The properties of the residue left after treatment were within the allowable limit for use as compost except for helminth egg concentration. Thus, in informal urban settlements, BSFL can be applied for effective treatment of FS from pit latrines while generating good quality residue thereby providing an additional value chain in FSM.
Application of value analysis concept on construction cost of low volume roads in Uganda
(Kyambogo University (un published work), 2019-11) Okello, Emmanuel
The success of implementation of highway infrastructure projects is usually measured against three parameters; quality, time and cost. However, some of these projects do not achieve expected project goals in terms of quality. Secondly, project delivery is not within a reasonable amount of time, and finally, costs are not in line with their budget limits. This study applied Value Analysis (VA) methodology in the construction of Low Volume Roads (LVRs) in Uganda, to mitigate the aspects of time and cost but still ensuring that the functionality and quality aspects are not jeopardized, through the generation of innovative alternatives. The methodology included document review and cost analysis of LVR projects previously implemented in ten districts in Northern and Eastern Uganda. In this study VA technique involved the employment of a composite or mixed method of work, incorporating both mechanization and manual labour during the Road Formation Phase (RFP), as opposed to the existing labour based methods. The VA technique was applied to two construction projects, that is: the construction of 800 meters of LVR in Financial Year (FY) 2017/18 in Kole District which project was undertaken by the researcher and during the construction of a 1,200 meter LVR in Bukedea District in the same year. Comparison of the cost when the VA is used, with the current cost through hypothesis testing was done, and the alternative hypothesis that the cost reduces on application of the mixed method VA technique during the Road Formation Phase (RFP) was upheld at 95% confidence level. It was established that average cost per metre of LVR when using the conventional labour methods was UGX. 250,000, while an average cost per metre of UGX. 228,157 was achieved when the mixed method approach was used, thereby realizing an 8.7% reduction in the average cost per metre of the construction of LVRs. The researcher thus concluded that the cost of LVR construction significantly reduces when VA is applied during the RFP. The researcher recommended the use of the mixed method VA technique for the ongoing and future LVR construction projects under the Low Cost Seal (LCS) Program and proposed that further research should be done to apply VA on the sealing phase of LVR construction. Key Words: Value Analysis, Cost per Metre, Mixed Method, Road Formation Phase, Low Volume Roads, Low Cost Seal.
Assessement of the impact of sawdust ash on the sulphate resistance of concrete during early strength development
(Kyambogo University, 2020-12) Basajjansolo Babiito, Patrick
Sulfates are detrimental to the structural integrity of concrete throughout its service life. In the project for the construction of the overhead transmission line grid for power evacuation from the Karuma Hydro Power plant, aggressive levels of sulfates were encountered along Karuma – Lira 132kV Transmission Line. This necessitated use of Sulfate Resisting Cement (SRC) in foundations to counter sulfate attack. Sulfate Resisting Cement is twice as expensive as Ordinary Portland Cement (OPC) in Uganda and may only be available on a minimum special order of 200 tons. Based on the above the study was therefore aimed at evaluating the impact of sawdust ash on the sulphate resistance of concrete during early strength development. A total of 384 concrete cubes of 4 designed mixes were used in two different sulphuric acid solutions of differing concentrations to simulate sulphate attack on concrete. Cubes were exposed to sulfate attack for 28 days in sulphuric acid solutions in the early stages of hardening (i.e., at the age of 6, 24 and 72 hours) and in the later stage of hardening (i.e., aged 28 days). SDA dosages used to replace part of the OPC were 0%, 5%, 10% and 15%. It was observed that concrete in the early stages of hardening (i.e., age of 6, 24 and 72 hours) exhibited improved resistance to sulfate attack compared to that in the later stage of hardening (i.e., aged 28 days). Moderate strength concrete grades (i.e., C16/20, C20/25) with design cement content less than 18.1% performed better than the higher strength concrete (i.e., C25/30 and C30/37). The ingress of SO4 2- ions into C20/25-5% SDA concrete followed a decreasing linear function for concrete cured for 72 hours before exposure to sulfate attack. A maximum cement replacement of 10% with SDA as well as partial back filling of foundation concrete after 72 hours of casting is
Assessing biogas recovery potential from organic Solid waste generated from academic institutions (case study: Islamic university in Uganda - Mbale city)
(Kyambogo University[unpublished work], 2022-09) Kayizzi, Patrick
Resource recovery is contingent to the circular economy and the core intention is to replace the norm of largely linear economy of take make and dispose with one where resource circulation and disposal is fostered at high value. One of the current trending strategies in waste minimization is resource recovery such as biogas given its undisputable benefits. Education institutions are considered as congregated communities that have significant social, economic and environmental impact on the environment. like local authorities, these institutions experience challenges of provision of satisfactory social services such as managing solid waste. Minimal efforts have been invested in carrying out research in waste management practices in school settings most especially establishing the potential of biogas recovery that can contribute towards reduced impact to the ecosystem. This study was therefore focused on exploring the biogas potential from solid organic waste generated from higher academic institutions in Mbale Municipality. The study first looked at solid waste management practices in sampled academic institutions and their respective main source of fuel for cooking; a checklist was prepared and 26 out of 36 sampled institutions willingly provided access to their premise. From the data gathered, 65% of the 26 institutions practiced onsite waste disposal mainly dumping in pits and burning while the other schools disposed of to the main landfill; 25 out 26 institutions utilized wood biofuels for cooking while 1 out of the 26 used electricity; none of the schools practiced resource recovery. A detailed assessment was then undertaken at Islamic University in Uganda to establish the quantity and composition of the waste generated within two distinct periods of the semester: one at the beginning (February) that represented the dry weather conditions and at the end of the semester (November) that represented the wet season. Results indicated that foliage pruning contributed the highest percentage of waste generated followed by kitchen waste while paper waste registered the least percentage contribution by both volume and weight; It was also noted that more waste generation was experienced during the wet season; hourly waste collection indicated peak collection/ generation between 1000-1200 while least collection was between 1200-1400hr with kitchen waste dominating between 0800-1000hrs and 1600- 1800 while foliage pruning dominated between 1000-1200hrs and 1200-1400hrs respectively. Biogas resource potential was investigated using a single stage biogas setup where co-digestion of the organic solid waste was used as substrate; eight sets of experiments were conducted with two identical sets per ratio for (paper, kitchen and grass) and 25% cow dung inoculant by weight of the total substrate weight under mesospheric conditions. Results indicated a high methane composition of 33% and a relatively low percentage of 13% for ratios of 1:19:7 and 1:5:7 (for paper: kitchen: grass) respectively. The potential of biogas in solid organic waste gave an indication of a virgin opportunity to explore harnessing resources from the organic waste generated from academic institutions that will in return provide an alternative for safe solid waste disposal as well as harnessing nature gas for cooking and manure for soil stabilization for ecosystem degradation mitigation. Key Words: Resource recovery, Biogas, Solid Organic Waste, Methane
Assessing impacts of climate change on hydrological extremes of Rwizi catchment
(Kyambogo University, 2019-11) Baraza, Gerald
There is lack of understanding on the impact of climate change on hydrological extremes of Rwizi Catchment. This threatens the sustainability of water to support socio- economic activities in the Rwizi Catchment. The procedure for conducting the study was guided by three objectives. Firstly, Trend analysis showed that precipitation mainly increased whereas Potential Evapotranspiration (PET) exhibited a decrease. The trend in both precipitation and PET were mainly insignificant. The second objective focused on establishing the climate change signals on precipitation and PET based on Global Circulation Models (GCMs) from Coupled Model Inter-comparison Project phase 5 (CMIP5) outputs. This was done by considering the Representative Concentration Pathways 4.5Wm-2 (RCP4.5) and 8.5Wm-2 (RCP8.5) scenarios. The precipitation and temperature of the 2050s and 2080s were projected to increase as to compared to the control period (1956–2002). Two conceptual hydrological models were calibrated and used for the impact assessment. Their difference in simulating the flows under future climate scenarios were also investigated. For the Austrian Water Balance Model (AWBM), the assembled mean projections of the high flow of 10- year return period for the 2050s and 2080s were projected to decrease. Whereas, for the Hydrological Model focusing on Sub-flows’ Variation (HMSV), the assembled mean projections of high flows were projected to increase. The results for the low flows reveal decreasing low flow quantiles for AWBM for the 2050s and 2080s. However, for HMSV model, it showed increasing low flows quantiles. These impacts of climate change on the river flow show the need for a careful planning of relevant and appropriate adaption measures at a catchment scale. Keywords: Climate change, Climate models, Hydrological models, Rwizi Catchment.
Assessing the applicability of earned value management Technique in enhancing performance of construction Projects in Uganda: a case of Kampala city
(Kyambogo University, 2021-07) Mugabi, Ronald
Monitoring is the most important component in project management. It deals with measuring performance of a project at certain time intervals and reports that performance to the organization for process control. Any project with considerable cost overrun and schedule delay typically gets in trouble at its beginning, and unfortunately, project managers do not realize this problem until late in the implementation when their ability to recover the project to achieve its planned objectives diminishes. This study aimed at assessing the applicability of Earned Value Management (EVM) technique on measuring the performance of construction projects in Kampala City, and adopted a mixed method research design that employed both quantitative and qualitative techniques. Data were collected and analyzed using SPSS software. The study established that among the standard practices used in measuring performance Critical Path method was the most commonly used. This means that emphasis should be put to understanding the effect of this method to performance of projects. It was further established that barriers that hinder the effective application of Earned Value Management Technique were as follows in descending significance, with the use of construction equipment having a significance level of 84.3%, followed by level of technology at 78.2%, labour ratesat 20.9%, and material prices at 19.7%; and based on these findings a performance monitoring tool for construction projects was developed as = − 5.698 + 0.197 + 0.181 + 0.036 + 0.009 . The study thus concluded that EVM techniques are less commonly used and less known than Critical path method and PERT method for measuring performance of construction projects. The study further concluded that the application of EVM on projects is greatly affected by labour rates, and material prices as indicated in the developed performance monitoring tool. It is envisaged that the developed tool will be useful in monitoring the performance of projects right from inception to completion paying most attention to equipment, technology in used, cost of labour and material costs. Key Words Earned Value Management, technique, Construction Projects, Performance Measurement, Kampala city.
Assessing the effect of different mortar mixes on strength of burnt clay brick masonry wall
(Kyambogo University(Unpublished work), 2019-10) Owino, Stephen
Following the tremendous increase in population growth rate in Uganda from 12.6 million people in 1980 to 34.6 million people in 2014, there has been an increase in housing units from 2.6 million house in 1980 to 7.34 million houses in 2014. Despite of this increase in housing units, the population has surpassed the demand leading to a deficit of 200, 000 housing units annually. The National Housing and population census of 2014 revealed that the increased housing units is constructed of permanent materials at 43.7% with burnt clay bricks leading at 36.4% followed by mud and poles at 33.6% and these are materials used without the knowledge of their strength and properties. Hence, the need to assess its strength so as to protect the inhabitants against accidents and loss of lives. Research findings indicated that 100% of the structural design firms do not design masonry structures made of burnt clay bricks but instead specify them as infills. 100% survey on 102 sites established that the commonly used mortar mix ratios range between 1:7 to 1:14 far different from the perceived mortar mix ratios of 1:3 to 1:6 as a result of the use of one bag of cement to a number of wheelbarrows and these resulted into a compressive strength of 5.92N/mm2 to 1.87N/mm2 respectively far below the intended compressive strength of 17.8N/mm2 to 6.82N/mm2. Experimental tests on burnt clay bricks has established varying compressive strength with an average of 7.3N/mm2 to 2.06N/mm2 and this was attributed to water absorption, method of manufacture and the soil type. Results on burnt clay masonry walls constructed of most used mortar mix ratios established that , the compressive strength of the wall greatly reduced with increasing value of mortar mix ratios. Conclusively, the wall strength was much influenced by the strength of mortar, indicating that the weaker the strength of mortar the weaker the wall strength and vice versa however strong the brick may be, hence high mix ratios beyond 1:6 should not be used in the construction of masonry clay brick walls to avoid structural failures.
Assessing the impact of bitumen types on the Performance of asphalt concrete road pavement construction in Uganda
(Kyambogo University (un published work), 2018-12) Mpaata, Steven
This research was conducted to assess the impact of local asphalt binders on the performance of asphalt concrete road pavement construction in Uganda. The bitumen samples were collected from ongoing road construction projects where asphalt concrete made pan of the pavement. The sampling was done in accordance with procedures provided in BS EN 58: 2012 and BS EN 475: 2000. Testing was carried out in Central Materials Laboratory, Tan Roads. Dar Es Salaam, Tanzania to confirm binder classification and obtain performance properties. The penetration tests, fluidity and pumping tests conducted on the bitumen samples confirmed compliance with specifications. It was noted that all penetration grade bitumen samples gave softening points lower than the allowable limits implying in-service performance challenges. Most of the samples did not comply with physical property requirements when compared with the binder specifications implying that they arc susceptible to rutting and fatigue damage. Binder Temperature zoning based on Strategic Highway Research Program of asphalt grading system was completed in fourteen zones and presented on a map. Three temperature zones were confirmed incorporating Perfom1ance Grade (PG) 70+ 3 in most of the Northern, far Eastern and Kasese regions, PG 64+6 for most of Central and PG 58+3 for far Western regions bordering with Rwanda and Democratic Republic of Congo. This study introduced a robust testing regime and acceptance criteria to be used in future asphalt designation and construction in Uganda. Accordingly. value engineering was achieved based on increased time intervals of road
Assessment of equipment productivity in building construction projects in Uganda
(Kyambogo University[unpublished work], 2018-12) Asaya, Andrew Peter
Management of construction equipment in building construction projects is an important factor to run projects in a successful manner. The focus of this study was to identify the factors affecting equipment productivity, to establish how these factors impacted on equipment productivity, with the aim of improving equipment productivity in Uganda. Using a cross sectional study design, data were collected from a total of 340 respondents in different construction sites in Kampala by use of questionnaires. Descriptive statistics were used to analyse the respondents' demographic characteristics and the mean and standard deviation was used to identify factors affecting construction equipment productivity. The identified factors were subjected to regression analysis and a model was developed to improve equipment productivity. The study established that human resource factors affecting equipment productivity were; technical skills of staff, experience of the operator, and motivation of staff. It was further established that equipment factors affecting equipment productivity were; equipment break down, quality of equipment, working cycle capacity, and age of equipment. With regards to the environmental factors affecting equipment productivity, the study found that weather conditions and access, were the leading factors affecting equipment productivity. It was established that holding other factors constant, environmental factors affect equipment productivity by 6.4% and the remaining 93.6% is explained by other factors. Project managers should therefore hire experienced and well-motivated equipment operators and in order to improve equipment productivity in building construction project. Key words: Equipment Productivity, Human resource, Environment, Building construction
Assessment of factors influencing performance of road construction projects in Uganda: a case study of ministry of works and transport
(Kyambogo University, 2020-02) Seninde, Stephen
The road construction projects in Uganda suffer from many problems and complex issues in performance such as; cost, time, scope and quality. The aim of this study was to assess the factors influencing performance of road construction projects in Uganda. The study adopted a descriptive research design and data were collected using questionnaires from 147 purposively selected respondents from Local construction companies, consultancy firms, and government officials from Ministry of Works and District Local governments. Relevant literature was reviewed to establish actual factors influencing performance of road construction projects in Uganda. Data were coded and entered into statistical packages for social scientists (SPSS) version 25. A total of 43 performance factors were identified and categorized into five factor groups. The data were analyzed descriptively using statistical correlation and regression analysis, multi-variate analysis and relative importance index (RII) was used to rank the identified factors. The study revealed five most significant and influential factors; contractors, clients/owners, contractor’s ability to mobilize to site, availability of funds, and cash flows, and three least influential factors; inadequate mobilization of resources, inadequate geotechnical and hydrological studies and lack of equipment. The study concluded that; contract management factors, project stake holders’ factors, and project financing factors significantly influence the performance of road construction projects in Uganda. The research study also recommended among others; setting aside finances for the project before commencement, putting in place competent supervision team for contract management, ensure fair and transparent procurement processes for proper performance of road construction projects. Key Words: Assessment, Performance, Road construction projects, relative importance index.

Browse

Browsing Faculty of Engineering by Title