Browse
Recent Submissions
Item Chemical Characterization of Pumice Material Sourced from Mbeya, Tanzania(MUST, 2025-02) Nyangi, PatricePumice, a lightweight volcanic material abundantly available in Mbeya, Tanzania, is underutilized and often discarded following excavation activities. In most construction projects within the region, conventional materials like clay soil, river sand, normal-weight aggregates, and cement are pre-dominantly used, leaving the potential of pumice largely unexploited. This study presents a comprehensive chemical characterization of pumice sourced from two locations, MUST main campus (Sample A) and Wimba (Sample B), to assess its suitability as a supplementary cementitious material (SCM). Energy Dispersive X-ray Fluorescence (EDXRF) analysis revealed that Sample A contained 70.3% SiO₂, 17.9% Al₂O₃, and 3.53% Fe₂O₃, while Sample B had 71.3% SiO₂, 17.3% Al₂O₃, and 3.38% Fe₂O₃. The combined SiO₂, Al₂O₃, and Fe₂O₃ content for both samples exceeded the 70% ASTM C618 threshold for pozzolanic materials, confirming strong pozzolanic properties. Additionally, K₂O was 5.21% in Sample A and 5.05% in Sample B, while CaO was 0.667% and 0.763%, respectively.SO₃ was detected at 0.448% (Sample A) and 0.482% (Sample B), and TiO₂ at 0.528% and 0.507%, respectively. Na₂O and MgO were not detected. The high levels of SiO₂ and Al₂O₃ suggest strong pozzolanic properties, while the low CaO content indicates that pumice would function primarily as a pozzolanic additive rather than a primary binder. Consequently, these findings confirm that pumice is better suited as a supplementary cementitious material (SCM) and filler rather than a complete replacement for cement. By partially replacing cement with pumice, it could be possible to reduce the carbon footprint, contributing to more sustainable construction practices.Item Application of the RUSLE model to estimate sedimentation in the Lwanyo Reservoir in Mbarali District Mbeya– Tanzania(IWA Publishing, 2025) Moshi, Baraka Moses; Katambara, Zacharia; Lingwanda, MwajumaThe constant increase in the global population is proportional to the increase in basic human needs associated with environ mental degradation. Sedimentation in water bodies poses socio-economic challenges as it lessens the storage capacities. The RUSLE model expresses the effect of sedimentation in the Lwanyo reservoir sub-catchment. Key factors influencing sedimentation include: maximum erosivity factor (R) is 421.39 (MJ mm ha 1 h 1 yr), the soil erodibility factor (K) is 0.071, the topographic factor (LS) due to catchment topography is 9.086, the vegetation cover and management factor (C) is 0.1045, and the conservation practice factor (P) is 0.14. The RUSLE model estimates soil sediment loss to be 3.977 tonnes/ha/year, as the average annual soil loss for the Lwanyo sub-catchment area is 39.6 km2. This value indicates that for every hectare, the average annual soil loss is 1.004 10 3tonnes/year, with silt as the dominant soil sediment being eroded. If no intervention measures are implemented, the sediment load could reach 119.31 tonnes over 30 years, reducing the reservoir’s storage capacity by 68.177 m3. Reducing human activity in the catchment and promoting afforestation to mitigate sedimentation can help increase soil stability and reduce erosion.Item Assessment of Temporal Variations in Shallow Well Water Quality Using Graphical Analysis and Water Quality Index in Half-London Ward, Tunduma, Tanzania(Mbeya University of Sience and Technology, 2025-03-01) William, Matungwa; Katambara, ZachariaShallow wells are vital for water supply in regions lacking centralised systems, but they are highly susceptible to contamination from anthropogenic activities and natural processes. This study investigated seasonal variations in water quality from five shallow wells in Half London Ward, Tunduma, Tanzania, over a 12-month period to assess biological, chemical, and physical parameters, to identify contamination drivers, and to propose sustainable management solutions. Using WHO and EPA guidelines, monthly water sampling was conducted for 12 months from June 2022 to May 2023. Parameters analysed included Faecal and Total Coliforms, Nitrate, Phosphate, Total Iron, Biological Oxygen Demand (BOD), pH, Electrical Conductivity (EC), Turbidity, Total Dissolved Solids (TDS), and Total Suspended Solids (TSS). The National Sanitation Foundation Water Quality Index (NSFWQI) was employed to classify seasonal variations in water quality. Results revealed significant seasonal trends. Microbial contamination peaked during the rainy season, with shallow well WW3 and WW5 recording faecal coliform levels of 5 CFU/100 ml and total coliforms of 18 CFU/100 ml, exceeding WHO and East African Standards. Phosphate levels in shallow well WW4 and WW5 exceeded the threshold of 2.2 mg/l, attributed to agricultural runoff. Elevated iron concentrations (1.85 mg/l) in WW4 reflected natural geological leaching. BOD and turbidity increased during wet periods due to organic pollutants and sediment influx, while physical parameters such as pH and TDS remained within permissible limits. The NSFWQI ranged from "Excellent" (18.6) in shallow well WW5 during winter to "Medium" (65.4) in shallow well WW3 during summer, highlighting contamination risks from surface runoff and poor land management. The study concludes that rainfall and proximity to pollution sources significantly impact shallow well water quality. It recommends implementing community-driven sanitation measures, protecting shallow wells, and conducting routine monitoring. These findings provide a framework for improving groundwater quality for domestic use in urbanising regions globally.Item Strategies for Local-less-competitive Contractors to Compete Against Overseas Counterparts: A Tanzania Case(Science Publishing Group, 2022-01-24) Tekka, Ramadhani Said; Kifanyi, Gislar EdgarThe consequence of globalization resulted from the world economic growth, development and the agreement on free market has necessitated the struggle for the global construction industry market competitive environment, which has largely affected the construction industry of developing and less-developed countries. Thus, un-maintainable and less competition resulted from several hindrances facing Local-less-competitive firms in less-developed countries has raised the need to identify effective strategies as a competitive advantage for improving and thus attaining an effective performance. A questionnaire survey tool was used to gather and collect potential data from the experienced construction industry practitioners and stakeholders including engineers, architects, quantity surveyors and surveyors. Ranking, factor analysis, and structural modeling techniques were adopted and hence facilitated the identification of twenty two (22) potential strategies for the sustainable competitiveness of Local-less-competitive firms. Assets (A), processes (P), performance (PER), and government support (GS) related strategies (β1=0.223, p=0.05; β2=0.208, p=0.04; β3=0.391; p=0.00, β4=0.153, p=0.06) respectively has proved to have an optimistic statistical positive significance prediction in accelerating sustainable competitiveness of local-less competitive firms of less-developed countries’ domestic market. The study findings may serve as valuable input for policymakers and construction industry stakeholders in understanding the effective strategies adopted by Local less competitive firms in domestic construction.Item Heavy Metals and Essential Elements in Table Salt Extracted From Bahi Wetlands in Central Tanzania(International Journal of Engineering, Science and Technology, 2022-03-04) Lugendo, Innocent J.; Bugumba, JohnSalt from Bahi wetlands is allegedly containing high concentrations of heavy metals since the wetlands are in the proximity of the prospective uranium mining sites. This means Bahi salt could be an important route through which salt consumers are exposed to high concentrations of heavy metals. This study has analysed 50 salt samples of Bahi salt in order to determine the concentrations of both heavy metals and essential elements using the Energy Dispersive X-Ray Fluorescence Spectrometry (EDXRF). Analytical results show that apart from Na and Cl, Bahi salt is composed of several elements including heavy metals such as Cr, Cd, Pb, Th and U. The salt also contains essential elements such as Mg, K, Ca, Mn, Fe, Co, Zn and Br. The mean concentrations of Cr, Cd, Pb, Th and U ranged from 20 - 25µg/g, 3.8 – 8.85 µg/g, 2.29 – 5.8 µg/g, 6.22 – 15.8 µg/g and 6.5 – 9.12 µg/g respectively. All these toxic elements were in higher concentrations than the recommended maximum tolerable limits (MTL). Meanwhile the daily intake rate of essential elements due consumption of Bahi salt leads to the hazard index (HI) greater than 1 for children. This implies that unless purified, Bahi salt may be unsafe for children. Thus, both salt producers and responsible authorities at Bahi wetlands should collaborate to introduce suitable production methods ensuring effective salt purification before it reaches its consumers.Item Improved method on hydraulic power calculations for conventional sucker rod pumping system(IOP Publishing, 2020) Mwangupili, O.E; Chunsheng, P; Bululu, C; Nyanswi, S.L; Muya, S. MThe annual energy consumption of suck rod pumping units in China is more than 10 billion kWh, but the average efficiency is only about 25-31%. Limited information is known, about the efficiency of various components of the pumping unit. The current methods for calculating the hydraulic power neglect the effect of friction and free gas. This research introduces an improved method for calculating hydraulic power which takes into account the effect of friction and free gas. The model was obtained from the product of two parameters which were, predicted pressure increased by the downhole pump and predicted flow rate. The pressure increased by the pump was obtained by the nodal analysis approach in which the concepts of multiphase flow were included. The Computer program was developed and all calculations in this paper were computed by this program developed from python programming language version 3.5. This model was compared with the previous models and showed that, the previous models underestimated the hydraulic power since the influence of gas and friction were not included.Item Energy Generation from Biomass in Tanzania Impacts and Challenges: An Overview(International Journal of Engineering Research & Technology (IJERT), 2020-05-05) Omari, Arthur M.; Tesha, Janet; Sarakikya, HalidiniAt present, much attention is on how to find the appropriate and proper renewable energy source which will offer sufficient energy output to replace the use of conventional fossil fuel sources. The energy stored in various biomasses available in Tanzania is huge and can provide sufficient energy to supply the rural societies. The energy crises facing rural societies in Tanzania can be solved and minimized by proper harnessing the substantial biomass available in the Country. The energy conversion process from the biomass and the type of energy required plays a vital role in identifying the type of biomass required in the process. The objective of this paper is to address different types of energy from various biomass sources, highlight the challenges and impact of each type.Item Simulation and Optimization of Municipal Solid Waste Combustion: A Case Study of a Fixed Bed Incinerator(2020) Omari, Arthur M.; John, John P.; Kichonge, BarakaIn this study, a Computational Fluid Dynamics (CFD) technique was used to develop a model for the simulation and flow conditions of the incinerator. The CFD technique are based on subdividing the volume of interest, i.e., the combustion chamber (or other parts of the plant) into a grid of elementary volumes. The relevant equations of conservation (mass, momentum, energy) are then applied to each of those elements, after defining all inputs, outputs and boundary conditions. The resulting system is then integrated from start to finish, after introducing momentum, mass and heat transfer. The objective of the study was to evaluate and optimize the performance of locally available incinerators in Tanzania. The small scale municipal solid waste incinerator modelling was done by using a fluent solver. The case study of the existing incinerator at a Bagamoyo hospital in Tanzania was used as a model and the obtained values were compared with simulated results and other publications for validation. The design optimization using CFD techniques to predict the performance of incinerator showed the deviation of input air by 14%, the mass flow rate by 26.5%, the mass fraction of carbon dioxide by 10.4% and slight deviation of nitrogen dioxide and carbon monoxide. The study suggested removing the ash during the incineration process by using a moving grate mechanism to minimize the possibility of formation of NOX. The study found the maximum mass flow rate capacity of incinerator to be 68kg/h with input air A1 as 0.03639 kg/s, input air A2 as 0.03046 kg/s and input air A3 as 0.03409 kg/s. The findings indicated that as capacity is scaled up, the available momentum declines relative to the dimensions of the furnace.Item The Use of Blended Cinder Aggregates for Concrete Mixes(IJSBAR, 2022) Chengula, Duwa H.The study to design concrete by using cinder blended aggregates was conducted in Mbeya Region Tanzania. Cinder aggregates were blended with crushed stones aggregates for concrete mixes. In Mbeya Region there are abundant volcanic materials which are pozzolan, cinders and pumices. The study involved characterization of source aggregates and for blended aggregates. The materials used for this study were natural cinder aggregates from Ituha, Crushed stone aggregates from Mbalizi and excavated pit sands from Ituha. The binder used was CEMI 32.5N manufactured by Tembo Lafarge Cement Company Limited. The results from strength and physical properties tests of aggregates indicated that Ituha cinder aggregates have low strength, low specific gravity and high water absorption compared to Mbalizi crushed stone aggregates. The strength results for Ituha cinder aggregates are 75kN for TFV, 38.76% for ACV and 48. 26% for AIV. The results of SG, WA, EI and FI for Ituha cinder aggregates are 1.77, 3.31%, 19.82% and 12.88% respectively. The strength results for Mbalizi crushed stones aggregates are 240kN for TFV, 15.82% for ACV and 18. 30% for AIV. The results of SG, WA, EI and FI for Mbalizi crushed stone aggregates are 2.63, 0.87%, 34.41% and 12.60% respectively. The SG and WA for Ituha pit sand are 2.44 and 3.18% respectively. Sieve analysis for Ituha cinder aggregates, Mbalizi crushed stone aggregates and Ituha pit sands were conducted. The aggregates and sands were blended together to get six blended sample materials targeting the selected aggregate envelopes for concrete mixes. The concrete were prepared for two different cement contents of 350kg/m3 and 450kg/m3 mixed at W/C ratio of 0.55. Due to high demand of mixing water the super plasticizer at 2.5% and 3% for cement content of 450kg/m3 and 350kg/m3 respectively were added to fresh concrete. The concretes were cured under water for 7days, 14days, 21days and 28days. The results for compressive strength indicated that the compressive strengths increased with increasing curing period and increased amount of Mbalizi crushed aggregates and cement contents. The compressive strength of concrete specimens mixed at cement content of 350kg/m3 cured for 28days are 23.8MPa for 55IPS45MCA00ICA, 22.3MPa for 50IPS36MCA14ICA, 20. 7MPa for 45IPS27MCA28ICA, 18.4MPa for 40IPS18MCA42ICA, 18.0MPa for 35IPS09MCA56ICA and 16.6MPa for 30IPS00MCA70ICA. The compressive strength of concrete mixed at cement content of 450kg/m3 cured for 28days are 27.8MPa for 55IPS45MCA00ICA, 29.0MPa for 50IPS36MCA14ICA, 26.1MPa for 45IPS27MCA28ICA, 24.6MPa for 40IPS18MCA42ICA, 22.9MPa for 35IPS09MCA56ICA and 22.2MPa for 30IPS00MCA70ICA. But also densities of cured concrete specimens for both cement contents increased with increased curing periods and amount of Mbalizi crushed aggregates. The increase in compressive strength with increased curing period and Mbalizi crushed aggregates is because of development of cementitious compound and high resistance against crushing. For this study for easy blending process of aggregate materials, the blending model have been developed, the model uses median particle size (MS) and grading factor (GF) as variables. To make use of strength of aggregate materials, the prediction model of compressive strength of 28days cured concrete specimens was developed. The model uses TFV, SG and cement content as variables.Item Evaluation of Source Rock Potentiality and Prediction of Total Organic Carbon Using Well Log Data and Inte- grated Methods of Multivariate Analysis, Machine Learning, and Geochemical Analysis(International Association for Mathematical Geosciences, 2021) Nyakilla, Edwin E.; Silingi, Selemani N.; Shen, Chuanbo; Jun, Gu; Mulashani, Alvin K.; Chibura, Patrick E.In this study, integrated approaches based on multivariate analysis (MVA), machine learning (ML), and geochemical analysis are proposed to investigate the potential of hydrocarbon reserves and total organic carbon (TOC) prediction. These approaches em- ployed the MVA technique as a future selection method in source rock evaluation. We used geochemical data from 30 core samples taken equally from wells SS-5 and SS-7. Geo- chemical parameters, namely TOC, free hydrocarbon, thermal pyrolysis hydrocarbon, hydrogen index, production index, and oxygen index, were determined for statistical eval- uation. IBM SPSS statistical software and MATLAB (R2020a) were used for MVA and ML, respectively. The performance of the models built using MVA and ML were evaluated by, among others, coefficient of determination (R2 ) and mean square error (MSE). Findings revealed that fair through good to excellent source rock with TOC ranging from 0.85 to 2.95 wt% are hosted in the Triassic beds of Tanga. A high 1.61% Ro at a mature peak of 463 °C predominates with the existence of type III/II kerogen that can produce both oil and gas. Considering TOC prediction from conventional well log data, optimized Gaussian process regression showed the best performance followed by MVA and support vector machine, giving the MSEs of 0.5629, 0.6172, and 0.7023, respectively. In terms of prediction accuracy, their R 2 values of 0.952, 0.9346, and 0.835, respectively, were in good agreement with the geochemical results. The concurrence of geochemical analysis, ML, and MVA revealed that the Tanga basin has great hydrocarbon potential of great economic importance. The study revealed that combining MVA and other methods can be applied to assess the hydrocarbon resource potential of other prospects around the globe.Item Modelling and Simulation of Performance of the Microgrid Frequency Stability Control during Unplanned Islanding: The Case Study of Mwenga Hydropower(Scientific Research Publishing, 2022) Francis,Eligard, K; Omari, Arthur M; ., John, John.PA grid connected microgrid connects to the grid at a point of common coupl ing. Due to the great inertia of the grid which accelerates and decelerates the generator when its frequency tends to deviate, the grid connected microgrid operates at a frequency of the infinity bus. Frequency instability is one of the major challenges facing the grid connected microgrid during islanding. The power demand variation causes the variation in rotor speed, resulting to fre quency deviation. Frequency can be brought back to standard by varying the power generation to match with the varying load. The performance of the fre quency stability control system at Mwenga hydroelectric microgrid has been studied. Through site visitation, the power demand and generation status da ta were collected and analysed for model preparation. The results of the study indicate that, during islanding, the Mwenga rural electrification project is ob served to be subjected to power imbalance which leads to frequency instabili ty. Although the frequency control system tries to keep the system at a no minal frequency by maintaining the continuous balance between generation and varying load demand, however the system still operates with large mag nitude of overshoot, undershoot and longer settling time.Item Afractional-Order Trypanosomabrucei Rhodesiense Model With Vector Saturation and Temperature Dependent Parameters(SPRINGER, 2020) Helikumi, Mlyashimbi; Kgosimore, Moatlhodi; Kuznetsov, Dmitry; Mushayabasa, Steadyand density of tsetse fly population. Precisely, ectotherm performance measures, such as development rate, survival probability and reproductive rate, increase from low values (even Temperature is one of the integral environmental drivers that strongly affect the distribution zero) at critical minimum temperature, peak at an optimum temperature and then decline to low levels (even zero) at a critical maximumtemperature. In this study, a fractional-order Trypanosomabrucei rhodesiense model incorporating vector saturation and temperature dependent parameters is considered. The proposed model incorporates the interplay between vectors and two hosts, humans and animals. We computed the basic reproduction number andestablished results on the threshold dynamics. Meanwhile, we explored the effects of vector control and screening of infected host on long-term disease dynamics. We determine threshold levels essential to reducing the basic reproduction number to level below unity at various temperature levels. Our findings indicate that vector control and host screening could significantly control spread of the disease at different temperature levels.Item Review of Correlations between Unconfined Compressive Strength (UCS) Values and Dynamic Cone Penetrometer (DCP–DN) Values of Stabilized Soils(Mbeya University of Science and Technology,, 2023-12-02) Baya, L; Lingwanda, MThis paper discussed test methods, test and sample types, types of stabilisers and soils, applications, and limitations of various developed relationships between UCS and DCP DN values. The review of correlations between unconfined Compression Strength (UCS) values and Dynamic Cone Penetration (DCP-DN) values of stabilised soils will provide guidance on the selection of suitable regression models from what is available in the literature to enable the estimation of UCS from DCP values. The DCP test was found to be economical, rapid, portable, easy to operate and understand, and the most versatile test that provides comprehensive results. Many studies and various nations have adopted the ASTM D6951 DCP equipment for use. Previous studies show that DCP DN values are affected by the soil type, stabiliser and curing period, particle size, plasticity, moisture contents, liquid limit, dry density, UCS, confinement in mould, and investigation depth. The various existing regression models are useful for quick estimation of in-situ UCS of stabilised layers since the termination of in-situ UCS is expensive, tedious, difficult, and time-consuming. However, these regression models must be used with caution as they are dependent on material properties and other factors that influence the DCP DN values. Furthermore, the available correlations cannot be treated as an absolute substitute for laboratory values, and their application requires experience and engineering judgment. This allows further research to develop multiple regression models to correlate UCS and DCP with the same compactive effort and mould size, which will consider material properties and the effect of confinement on the laboratory DCP DN test in the standard mould.Item Assessment of Spatial Water Quality Variations in Shallow Wells Using Principal Component Analysis in Half London Ward, Tanzania(Scientific Research Publishing, 2025-02-21) Matungwa, William; Katambara, ZachariaGroundwater is a crucial water source for urban areas in Africa, particularly where surface water is insufficient to meet demand. This study analyses the water quality of five shallow wells (WW1-WW5) in Half-London Ward, Tun duma Town, Tanzania, using Principal Component Analysis (PCA) to iden tify the primary factors influencing groundwater contamination. Monthly samples were collected over 12 months and analysed for physical, chemical, and biological parameters. The PCA revealed between four and six principal components (PCs) for each well, explaining between 84.61% and 92.55% of the total variance in water quality data. In WW1, five PCs captured 87.53% of the variability, with PC1 (33.05%) dominated by pH, EC, TDS, and microbial contamination, suggesting significant influences from surface runoff and pit latrines. In WW2, six PCs explained 92.55% of the variance, with PC1 (36.17%) highlighting the effects of salinity, TDS, and agricultural runoff. WW3 had four PCs explaining 84.61% of the variance, with PC1 (39.63%) showing high contributions from pH, hardness, and salinity, indicating geological influences and contamination from human activities. Similarly, in WW4, six PCs ex plained 90.83% of the variance, where PC1 (43.53%) revealed contamination from pit latrines and fertilizers. WW5 also had six PCs, accounting for 92.51% of the variance, with PC1 (42.73%) indicating significant contamination from agricultural runoff and pit latrines. The study concludes that groundwater quality in Half-London Ward is primarily affected by a combination of surface runoff, pit latrine contamination, agricultural inputs, and geological factors. The presence of microbial contaminants and elevated nitrate and phosphateItem Investigation Of Properties Of Mbeya Pumice Lightweight Aggregate(JOURNAL OF THE INSTITUTION OF ENGINEERS TANZANIA, 2021-12) Shiganza, Oscar J.; Mboya, Hieronimi A.; Msambichaka, Joseph J.The properties of concrete depend partly on the type and mechanical properties of aggregates used in the concrete mix. The paper presents an investigation designed to study the properties of pumice lightweight aggregates and assess their suitability to structural lightweight concrete. The properties of pumice lightweight aggregates mainly aggregates shape, water absorption, specific gravity and organic impurities were examined. The results indicated that pumice lightweight aggregates have the flakiness and elongation close to upper limits as set by BS 812-105.1:1989 low density, high water absorption in comparison to normal weight aggregates, and are weather resistant. It was concluded that pumice lightweight aggregates are suitable for manufacture of structural lightweight concrete.Item Comparative Study of Bachelor of Civil Engineering Curricula in Higher Learning Institutions in Tanzania: A Systematic Review(IISTE, 2021-10-31) Mhando, Yusuph B.; Kifanyi, Gislar E.This paper compares the curricula of Bachelor degree in the field of civil engineering. This helps improving the quality of curriculum that generates demand driven engineering graduates with an equal competency in the context of labour market. Descriptive survey was adopted, and a checklist of courses from purposively selected higher learning institutions was used. Constant comparative analysis to categorize types of information investigated was adopted. Findings indicate that Bachelor degree programme in civil engineering at Dar es Salaam Institute of Technology (DIT), Mbeya University of Science and Technology (MUST) and St. Joseph College of Engineering and Technology (SJCET) has duration of 3 or 4 years depending on the entry qualification of the student, whereas at Arusha Technical College (ATC) it takes 3 years to complete the programme. On the other hand, inconsistency on the number of courses and academic loads offered in these institutions was revealed. The study suggests a joint development of curricula for training programmes. This could help trainers, researchers, curricula developers and policy makers to harmonize and minimize discrepancies of the curricula contents of the same programme offered in different institutions.Item Scrutinization of Chemical Reactions, Permeability, and Magnetic Field of A Dissipative Flow Effects of Silver (Ag) Nanoparticles – Water Over A Moving Vertical Porous Medium.(ELSEVIER, 2025-01-03) Lutera, Joseph N.; Shekar, MN Raja; Goud, B. ShankarIncompressible nanofluid flow applications have recently drawn significant attention among scientists and engineers. The dimensionless leading comparisons of this study are analytically executed using the Laplace transformation technique and graphically analyzed through the MATLAB software tool. The silver nanoparticles water thermophysical properties framed this exploration setting. This study finds that magnetic activity slows down the speed of the nanofluid flow. The solutes are consumed during the chemical reaction process, declining the concentration of species. The augmentation in solid volume fraction sinks the velocity and upsurges the nanofluid’s flow temperature. The permeability and thermal radiation constraints enhance the skin friction coefficient. These results provide valuable insights into designing and controlling mass and heat transmission in nanofluid-based schemes, such as creating heat exchangers, cooling schemes, electrochemical systems, and filtration processes in industries. It is also applicable in the health sector, for instance, by using a magnetic field to control the targeted area for drug injection in the human body.Item Regionalization of Mean Annual Flow for Ungauged Catchments in Case of Abbay River Basin, Ethiopia.(Springer, 2020-10-31) Nega, Habtamu; Seleshi,YilmaStreamflow measurement is one of the features of Ethiopia and other developing countries suffer to estimate. Climate variable (rainfall) and physiographic variables (catchment area, land slope, and elevation) were selected to develop a regression model equation that can be used to estimate the mean annual flow for ungauged catchments in the Abbay river basin. 70% of 27 hydrometric stations were used to train the regression model, and the remaining 30% were used for validation. Furthermore, statistical tests were used for selecting the best trustworthy model. The result shows that both catchment area (A) as the only predictor with both coefficients of determination (R 2 ) and Nash–Sutcliffe efficiency (NSE) value of 0.93 and catchment area (A), mean annual rainfall (MAR), and the average elevation (AE) as predictors with both coefficients of determination (R 2 ) and Nash–Sutcliffe efficiency (NSE) value of 0.96 regression equations were the trustworthy models. Moreover, the validation analysis was performed for nine stations distributed in the study area and resulting from a statistical test and graphical visualization the second regression model equation was a trustworthy model. The model parameters (catchment characteristics) are easily accessible for practitioners that want to estimate the mean annual flow in the study area.Item Characterizing Hydrological-Sensitive Areas of The Kinyerezi River SubCatchments in Dar Es Salaam, Tanzania Using The Topographic Index Approach.(IWA Publishing, 2023) Swilla, Livingstone; Katambara, Zacharia; Lingwandaa, MwajumaSeveral areas experience frequent floods due to anthropogenic activities. Among them, is the Dar es Salaam city, which experiences frequent floods along the Msimbazi River, whose flows originate from different tributaries including the Kinyerezi River. This study aims to evaluate the hydrological-sensitive areas of the Kinyerezi River sub-catchments using topographic index values (λ*) that enable the identification of areas with a higher probability of generating surface runoff. A digital elevation model was utilized to delineate the Kinyerezi River sub-catchment characteristics using ArcGIS 10.4. Soil infiltration rates (Ks) on selected open places were determined using a Guelph permeameter. Soil particle size distributions were analyzed and the λ* values were evaluated. The results showed the particle size distribution contains sand and silt-clay ranging from 46 to 84% and 16 to 53%, respectively. The Ks ranged from 0.6 to 7.8 mm/h while the sub-catchment KS3 scored the highest λ* value of about 10.7. Hence, there is a higher probability for generating surface runoff. Sub-catchment KS16 scored the smallest λ* value of 5.7, perceived to generate less surface runoff. Low-impact development practices capable of capturing runoff and enabling infiltration, evaporation, and detention should be employed in sub-catchments with higher λ* values.Item Quantifying Suitable Low-Impact Development Practices in Mitigating Runoff Floods for the Kinyerezi River Catchment in Dar Es Salaam, Tanzania.(IWA Publishing, 2024) Swilla, Livingstone; Katambara, Zacharia; Lingwandaa, MwajumaAs cities expand, changes in land use increase the runoff quantities. Impermeable catchment areas contribute to peak flows, causing floods in insufficiently capacity river reaches. The rate of urbanization witnessed in the Kinyerezi River catchment in Dar es Salaam has contributed to floods in the Msimbazi River. The low-impact development (LID) practices that include bioreten tion (BR) ponds, rain barrels (RBs), rain gardens (RGs), vegetative swales (VSs), constructed wetlands (CWs), etc., can be utilized to mitigate a portion of the surface runoff. This study aims to quantify the suitable LID practices for the Kinyerezi River catch ment in mitigating a portion of runoff floods. The sub-catchment physical characteristics and soil infiltration rates (Ks) were matched with each LID sitting requirements and later by multi-criteria decision-making (MCDM). The results on matching sub-catchment characteristics and LID sitting requirements indicated that BRs, RBs, VSs, RGs, and CWs were the preferable LIDs while MCDM analysis indicated the BRs, RGs, and RBs more appropriate. The BRs, RGs, and RBs were quantified to be 101, 3,698, and 3,698, respectively, within the catchment. BRs are recommended for catchment use while RBs and RGs are recommended for residential buildings. The RBs have the advantage of promoting water-demanding economic activities.
- «
- 1 (current)
- 2
- 3
- »