Engineering Commons^™

Feasibility Of Acetylated Icacina Trichantha Oliv. Tuber Starch As Viscosity And Fluid Loss Control Agents In Water-Based Drilling Mud. A Comparative Assessment With Commercial Starch, Kennedy I. Ogunwa, Theresa O. Uchechukwu, Ozioma Achugasim, Leo C. Osuji, Onyewuchi Akaranta

Tanzania Journal of Science

The need for sustainable, non-food drilling fluid additives has prompted the feasibility assessment of acetylated Icacina trichantha tuber starch as a viscosity modifier and fluid loss control agent in water-based muds. Native starch was acetylated to obtain two derivatives (Degree of Substitution DS = 0.38 and 0.68) and characterized using FTIR, swelling power, and physicochemical analyses. Drilling mud performance was assessed through rheology, gel strength, filtration loss, sorptivity, and model fitting. Acetylation improved swelling and reduced gelatinization temperature. The optimal formulation, Mud-ITO-ACS2 (DS = 0.68), exhibited the most favorable performance, combining low plastic viscosity (6 cP vs 9 cP for …

Improving The Concrete Compressive And Flexural Strength With A Low Fraction Addition Of Carboxylated Nitro-Oxidized Cellulose Nanofibrils From Banana Rachis, Ngesa Ezekiel Mushi, Emmanuel Kagya

Tanzania Journal of Science

Conventionally, concrete strength depends on the bonding interface, especially in hydrated products such as calcium silicate hydrate (CSH). As a result, concrete is sensitive to tensile load. With its unique properties, a low fraction of carboxylated nitro-oxidized cellulose nanofibrils (NOCNF) from the banana rachis is employed to improve the mechanical performance of the concrete nanostructurally. Compressive and flexural strength using the NOCNF content at 0, 0.05, and 0.1 wt.%, cured for 7 and 28 days, were evaluated. Notably, the compressive strength increased by 16 % and the flexural strength by 13 % at 0.1 wt.% NOCNF compared to plain concrete …

Assessment Of The Radionuclide Concentration Levels Of Water And Sediments Along The Mara River, Gasper Kachenge, Abubakary Salama, Abdalah Kileo, Furaha Chuma

Tanzania Journal of Science

For many years, several factors have impacted the water quality of the Mara River, including population growth, agricultural expansion, livestock keeping, mining, and industrial activities. These factors have intensified water pollution and climate change effects around the river. While previous studies have mainly focused on assessing heavy metal pollution risks on the Mara River, this study evaluates the concentration levels of radionuclides in boreholes, water, and sediments along the river and its tributaries. Naturally occurring radioactive materials, including 226Ra, ²³²Th, and ⁴⁰K, were evaluated. A high-purity germanium radiation detector (HPGe) with a coaxial detector system coupled with Gamma Vision software …

The Role Of Zinc Precursor Concentration In Modulating The Structural, Optical, And Electrical Properties Of Sol-Gel Derived Czts Thin Films, Justine John Tibaijuka

Tanzania Journal of Science

This study reports on CZTS thin films fabricated by sol–gel spin coating using zinc acetate dihydrate, copper acetate dihydrate, tin chloride, and thiourea dissolved in methanol with monoethylamine as a stabilizer. The films were annealed rapidly at 540 °C by using an RTP furnace. Results show the significant influence of zinc concentration on films’ properties with band gap evolution between 1.46 and 1.7 eV, along with high absorption coefficients exceeding 10⁴ cm⁻¹ in the visible range. Structurally, the films evolved from poorly crystalline at low Zn content to well- crystallized, (112)-oriented kesterite near stoichiometry. However, excessive Zn caused slight degradation …

Load Profile Analysis And Forecasting For Rural Mini Grids In Uganda, Prossy Mutesi, Santos L. Kihwele, Emmanuel S. Matee

Tanzania Journal of Science

Accurate load forecasting is essential for the reliable and cost-effective operation of rural mini grids, where constrained generation capacity and high penetration of renewable energy resources require well-informed operational decisions. This study examines electricity demand characteristics and forecasting performance for the Buzaami and Ssenyondo mini grids in Uganda, with particular focus on diurnal load profiles, peak demand behavior, and seasonal variability. 2022 operational data show extended peak demand from early morning to late evening, driven by socio-economic activities that strain resource scheduling and reliability management. To address these challenges, the study evaluates and compares Long Short-Term Memory (LSTM) networks, fuzzy …

Optimization Of Bio-Briquettes Production From Cassava Stems Co-Blended With Sisal Bole Bagasse Using Response Surface Methodology, Agnes Nshoma Msobi, Neema O. Msuya, Kando Khalifa Janga

Tanzania Journal of Science

This research aimed at producing bio-briquettes from cassava stems and sisal bole bagasse as an alternative source of cooking energy. A Response Surface Methodology (RSM) with Face - Centered Central Composite Design (FCCCD) featured a multi-objective optimization of the effect of the production parameters, focusing on maximizing char yield and Higher Heating Value (HHV) of the produced briquette while minimizing carbonization temperature and residence time. The findings showed that bio-briquettes produced at the lowest temperature (250 ℃) and residence time (30 min) and the blending ratio of 75% by 25% had the highest char yield of 76.92% and HHV of …

Elemental And Mineralogical Characterization Of Permo-Carboniferous Coal In The Ngaka Coalfield, Southwest Tanzania: Implications For Coal Quality Variation, John W. Gama, Justina J. Saroni, Remigius L. Gama

Tanzania Journal of Science

Coal from heterolithic seams exhibits distinct chemical characteristics due to interbedded non-coal beds, which influence its quality and usability. Despite extensive research in these settings, the elemental and mineralogical characteristics of the heterolithic sequences of the Mchuchuma Formation (K2) in the Ngaka Coalfield remain poorly documented. This study provides the first detailed assessment of K2 seams across five active mine sites. Eleven representative samples were analyzed using proximate, elemental, and mineralogical techniques, supported by Pearson correlation, binary analysis, and Principal Component Analysis. Proximate analysis revealed that ash content varies across mine sites, with values ranging from 9.17 to 25.03%, volatile …

Effects Of Bending And Re-Bending On Mechanical Properties Of Locally-Manufactured Steel Rebars, Patrick W. Waruhiu, Simon I. Marandu, Mussa I. Mgwatu

Tanzania Journal of Science

Steel rebars experience deformation when subjected to bending and re-bending operations. Subsequently, their microstructures are impaired thus affecting the mechanical properties and leading to failure. This study establishes the effects of bending and re-bending the steel rebars on the mechanical properties. Experiments were conducted to determine the effects of bending and re-bending of the steel rebars. Testing was conducted on Ten virgin and Thirty specimens which were bent and re-bent at 45º, 90º, and 180º, and followed by tensile tests. Yield strength, ultimate tensile strength, elongation, and ultimate tensile strength to yield strength ratio (Rm/Re), were recorded. Results showed the …

Preparation Of 2d Tungsten Diselenide (Wse2) Thin Films By Selenization Of Dc-Sputtered W Precursors, Lwitiko P. Mwakyusa

Tanzania Journal of Science

Two-dimensional layered transition metal dichalcogenides based on WSe2 films demonstrated promising properties for nano-electronics and photovoltaic applications. In this work, WSe2 films were prepared by selenization of DC-sputtered W precursors. The influence of the selenization temperature on the structural, morphology, and optical properties of the WSe2 films was investigated. The selenization temperature was varied from 350 °C to 450 °C at the interval of 50 °C. Structural, morphology and optical properties of the WSe2 were investigated using X-ray diffractometry (XRD), Atomic Force Microscope (AFM), and UV-VIS-NIR spectrophotometer, respectively. XRD analysis revealed that all WSe2 were polycrystalline and exhibited the co-existence …

Adsorption Of Water Vapour On The Microstructure And Stability Of Cu-Zn Bimetallic Coordination Polymer, Bukunola K. Oguntade, Gareth M. Watkins

Tanzania Journal of Science

A current challenge in the design of synthesis lies in the incorporation of two or more transition metals into a coordination polymer. The most widely used approach has been to incorporate a second metal as a generally innocent (coordinatively saturated) part of a linear linker as in the case of multifunctional carboxylated porphyrins (MCPs). The empirical method has been used to obtain many other types of MCPs; however, the selective, direct replacement of one transition metal within a monometallic coordination polymer via controlled stoichiometry has not generally led to maintained structural fidelity. In this present work, three pyromellitic acid complexes …

Spatial And Temporal Solar Potential Variation Analysis In Uganda Using Measured Data, Daniel N Katongole, Karidewa Nyeinga, Denis Okello, Daniel Mukiibi, James Mubiru, Yeeko Kisira

Tanzania Journal of Science

The paper presents an analysis of spatial and temporal solar potential variations in Uganda. The solar radiation potential distribution was investigated based on measured data from 56 ground meteorological stations across Uganda from January 2015 to February 2022. The data were recorded after every 5-minute interval. The monthly average daily Global Horizontal Irradiance (GHI) was analysed using the spatial inverse distance weighting (IDW) interpolation technique in ArcGIS 10.7.1. The GHI distribution was found to have maxima at equinox and minimum between June and July. The average global horizontal irradiation is found to be 1680 KWh per year, with a daily …

Effects Of Multilayer Structure On The Microstructure And Optical Properties Of The Dc Sputtered Chromium Thin Films For Selective Solar Absorber Applications, Justine J. Tibaijuka, Margaret E. Samiji, Mmantsae Diale, Nuru R. Mlyuka

Tanzania Journal of Science

Chromium thin films exhibit several properties that make them potential for solar thermal applications. In this work the effect of film thickness and sputtering power based multilayer structure on the optical properties of DC sputtered chromium thin films is reported. The structural, topological, and optical properties of these films were determined by X-ray diffractometer, Atomic Force Microscopy, and Ultraviolet-Visible-Near Infrared spectrophotometer, respectively. XRD spectra revealed a single peak with preferential orientation of (200) and (210) for single layer and multilayer chromium films, respectively. The grain size and roughness were relatively higher for the multilayer compared to single layer Chromium films. …

Optimal Design Of Hybrid Renewable Energy For Tanzania Rural Communities, Ester T Marcel, Joseph Mutale, Aviti T Mushi

Tanzania Journal of Science

Rural communities in developing countries lack access to electricity due to high costs of grid extension. This paper proposes a hybrid system of renewable energy (HRES) as solution. The HRES consists of solar, wind, and battery energy storage (BES). The village called Ngw’amkanga in Shinyanga region of Tanzania, East Africa is selected as a case study. An iterative method to determine the size of wind and solar photovoltaic (PV) generation required assuming a project life of 25 years at minimum annualised cost of the system ( ) is proposed. The project life time is fixed on the life span of …

Critical Analysis Of Material Consumption And Cost Reduction Techniques For The Apparel Cutting Processes, Ismael Taifa, Ibrahim Twaha, Mboka A Mwakibambo

Tanzania Journal of Science

Revenues generation in the garment industry is synonymous with material consumption. This study thus analysed material consumption and cost reduction techniques in the Tanzanian garment industry. The research employed quantitative (experimentation) and qualitative approaches (document review and observation technique) in the apparel cutting processes. Experimental results of material consumption from ten tests averaged efficiency of 78.67%, the wasted pieces (19.2%), and unnoticed waste (2.03%). Essential considerations to reduce material waste include: digitalising the fabric cutting processes; providing workers training; deploying appropriate practices in the cutting room (e.g. pattern engineering and pattern accuracy); considering the quality of the procured fabric and …

Coal Exploration Using Electrical Resistivity Method In Some Parts Of Benue Trough, Nigeria, Saminu Olatunji, Abdulgafar T. Jimoh

Tanzania Journal of Science

Geoelectrical resistivity sounding technique was used to delineate the occurrence and extents of coal seam. Fifteen points were sounded with Schlumberger configuration in the suspected coal deposit site bounded by longitudes 7.344° E and 7.366° E, and latitudes 7.318° N and 7.33° N. The vertical electrical sounding (VES) data were analyzed and the corresponding geo-electric parameters at various depths were modeled. The earth model within the study area was correlated with available lithology of a nearby mine site. The sounding signatures are KQHK and KHK curve types which revealed five to six distinct geo-electrical equivalent layers. The wet to dry …

Evaluation Of The Mechanisms And Effectiveness Of Nano-Hydroxides, Wood And Dairy Manure-Derived Biochars To Remove Fluoride And Heavy Metals From Water, Anna Rose Wallace, Wenjie Sun Dr, Chunming Su Dr

Civil and Environmental Engineering Theses and Dissertations

The development of effective treatment processes for the removal contaminants, such as fluoride and heavy metals, from polluted water have been urgently needed due to serious environmental health and safety concerns. In this dissertation, a variety of materials including various (hydro)oxide nanomaterials, biochars and surface modified biochar were studied to evaluate their effectiveness and mechanism on removing fluoride or mixed heavy metals from water.

In the Chapter 2, this study investigated the adsorptive removal of fluoride from water using various (hydro)oxide nanomaterials, focusing on ferrihydrite, hydroxyapatite (HAP) and brucite, which have the potential to be used as sorbents for surface …

Effects Of Aluminium And Tungsten Co-Doping On The Optical Properties Of Vo2 Based Thin Films, Cephas J Lyobha, Nuru R Mlyuka, Margaret E Samiji

Tanzania Journal of Science

Aluminium and tungsten co-doped vanadium dioxide (VO2:W:Al) thin films were deposited by DC reactive magnetron sputtering technique. In this work we report on the effects of aluminium and tungsten co–doping on the optical properties of vanadium dioxide (VO2) based thin films with a view of combining both increased luminous transmittance (Tlum) and lowered transition temperature (τc). The effect of aluminium and tungsten co-doping on semiconductor-metal transition of vanadium dioxide films was investigated and compared with tungsten doped and undopedVO2films. Spectral transmittances of the films were obtained using Shimadzu SolidSpec-3700 DUV UV-VIS-NIR spectrophotometer. The results revealed that the transmittance of tungsten …

Hall Effect Parameters Of Aluminium And Tungsten Co-Doped Vo2 Thin Films, Mohamed Mussa, Nuru R Mlyuka, Margaret E Samiji

Tanzania Journal of Science

The Hall Effect parameters of Al and W co-doped VO2 thin films were studied in order to explain the effect of co-doping on the electrical properties of thermochromic VO2 films. The carrier concentrations and conductivity of the films were found to increase with increase in temperature while carrier mobility decreased reaching a minimum around the transition temperature then slightly rose and became stable at high temperatures. Tungsten doped films displayed higher carrier concentrations and conductivity on both sides of the metal insulator transition and lower mobility compared to undoped and Al and W co-doped VO2 thin films.

Optimization Of Zinc To Tin Ratio In A Sol Gel Precursor Solution On The Growth And Properties Of Annealed Czts Thin Films, Justine John Tibaijuka, Margaret E Samiji, Nuru R Mlyuka

Tanzania Journal of Science

CZTS thin films were deposited by sol–gel spin coating method using precursor solutions prepared by dissolving copper acetate dihydrate, zinc acetate dihydrate, tin chloride and thiourea in methanol and monoethylamine then annealed in RTP furnace at 500 °C. Sol–gel precursor solutions were prepared with different Zn/Sn in a precursor solution and were annealed at different time intervals; and their effects on the optical and electrical properties of CZTS (Cu2ZnSnS4) films were investigated. The optical band-gap values were estimated to be between 1.30 and 1.88 eV while the absorption coefficients were in the range of 104 cm–1 in the visible region. …

Total Electron Content Derived From Global Positioning System During Solar Maximum Of 2012-2013 Over The Eastern Part Of The African Sector, Emmanuel D Sulungu, Christian Bs Uiso, Patrick Sibanda

Tanzania Journal of Science

This work presents results of diurnal, seasonal and latitudinal variations of vertical Total Electron Content (TECv) derived from GPS receivers at four locations, [Dodoma (6.19oS, 35.75oE), Mzuzu (11.43oS, 34.01oE), Zomba (15.38oS, 35.33oE) and Tete (16.15oS, 33.58oE)] during the solar maximum period of 2012 – 2013. The receivers are located directly below the EIA and at approximately the same longitude, ~ (33 – 3 oE) within the eastern part of the African sector. Diurnal and latitudinal variations of TECv are presented for an average of the five (5) quietest days of each of the four seasons: March equinox, June solstice, September …