Tanzania Journal of Science

Interpretation of Breakage Mechanisms in Comminution Processes by Using Particle Shape Properties: The Case Study at Buzwagi Comminution Circuit

Sospeter P. Maganga, Alphonce Wikedzi, Kaniki Tumba — Mon, 14 Apr 2025 00:00:00 +0000

This study interprets the breakage mechanisms at Buzwagi comminution circuit by using particle shape properties. The particle shape properties of aspect ratio, angularity, convexity and solidity were acquired from a mineral liberation analyser using DataView software. The results indicated that ground particles at Buzwagi comminution circuit were more elongated with mean aspect ratio ranges from 1.5893 to 1.6426, less angular with mean angularity values from 0.3770 to 0.4137 and smoother with mean convexity values from 0.9766 to 0.9817. The study concludes that ore particles at Buzwagi comminution circuit were ground by the combination of impact as a dominant mechanism and abrasion as a less dominant mechanism. The information on particle shape properties from comminution circuit can be used to predict the performance of downstream processes such as gravity and flotation.

A Review on Thermal Energy Storage Media and Technology for Flat Plate Solar Collectors: Experimental and Modeling Perspectives

David O Ng’anga, Maxwell Mageto, Hussein Golicha, Francis M Gaitho — Mon, 14 Apr 2025 00:00:00 +0000

Solar thermal conversion by collectors used in solar water heating systems solar thermal power generation systems undergo thermal losses. Hence there is need for the application of thermal storage media through appropriate technologies. These technologies require the use of various thermal storage media. A study and detailed discussion on thermal storage methods, sensible heat storage systems, sensible heat storage technologies, thermal storage materials and their applications are the aim of this review paper. This is done through analysis of thermal performance of flat plate solar collector, and the effects of the thermal parameters of the solar thermal storage systems as well as the functioning parameters on heat transfer fluids. Both experimental and modeling work on the application of thermal storage media are analyzed and discussed in this paper. Research findings show that thermal storage media improve the efficiency of solar water collectors by reducing thermal losses by these systems. This review is concluded by identifying various heat storage fluids for flat plate solar collectors which can improve their thermal performance for various heating applications.

Geophysical delineation of the geology and subsurface features of the Iramba area, central Tanzania, using aero-geophysical data with implications for mineral deposits

Peter Laizer, Gabriel D Mulibo — Mon, 14 Apr 2025 00:00:00 +0000

The Iramba area, known for its gold, base metal, and metallic mineral deposits, is not geophysically well exploited. The research presents an in-depth geophysical interpretation of the geology and the subsurface geological features and delineates hydrothermal alteration zones related to mineralisation in the area. The study involved detailed analysis and interpretations of high-resolution aero–geophysical data. Results from radiometric data have identified new granitic rocks and revealed a unique prominent feature in the region, which was previously not mapped. The identified new xenolith and foliated granites are characterised by high concentrations of all radiometric elements. The revealed prominent ring-like, NE trending feature is characterised by a high K concentration with moderate to high Th concentration. The feature shows significantly lower values of the Th/U ratios at the centre than the surrounding with intermediate magnetic signatures at the centre surrounded by high magnetic signatures. The study has also delineated zones of high K that coincide with low Th and Th/K ratio, indicating hydrothermally altered rocks and mineralisation in the area. The practical implications of this study are the future exploration and development of mineral resources for small-scale miners or larger-scale industrial mining in areas where mineralisations have been proposed.

Joint Modeling for MC-TDMA and Beamforming in mmWave Communications

Kwame S Ibwe — Mon, 14 Apr 2025 00:00:00 +0000

The increasing demand for ultra-high data rates and low-latency communication in next-generation wireless networks has led to the exploration of millimeter-wave (mmWave) frequency bands. These frequency bands offer significant bandwidth but are challenged by severe path loss, high susceptibility to blockage, and complex channel conditions. To address these challenges, a joint system modeling framework that integrates multicarrier time-division multiple access (MC-TDMA) with beamforming techniques is introduced. This study presents an analytical model that combines MC-TDMA’s flexible time-slot allocation with the high directionality and interference mitigation capabilities of beamforming, tailored to the unique characteristics of mmWave channels. Two optimization algorithms are proposed based on dynamic resource allocations for time slot allocations and hybrid beamforming respectively. Simulations experiments are performed under realistic propagation conditions, considering number of base station antennas, radio frequency (RF) chains, number of users and channel paths. Results demonstrate superior performance over existing schemes. The proposed schemes are verified to have smaller spectral efficiency gaps when compared to the fully-digital beamforming method. The findings offer a practical solution for high-capacity, low-latency communication in dense and dynamic mmWave environments, paving the way for more efficient next-generation networks design.

Efficient Energy Mix Model for Households in Dar es Salaam

Nuhu Nihamba, Neema Msuya, Abraham K Temu — Mon, 14 Apr 2025 00:00:00 +0000

The study analyses energy consumption in Dar es Salaam and assesses a range of energy sources, including solar power, liquefied petroleum gas (LPG), grid electricity, charcoal, firewood, and natural gas. By analysing the characteristics, costs, and benefits of each energy source, the study proposes an optimal household energy mix that enhances energy security, minimizes environmental impact, and reduces costs. Secondary data on existing energy practices were collected, and various energy mix scenarios were simulated using optimization techniques such as combined heat and power (CHP) systems and load-following strategies to ensure optimal performance while maintaining energy sustainability. Implementing this optimized energy mix model reduces household energy expenses by integrating cost-effective energy carriers and efficient technologies. Households benefit from lower electricity and fuel costs through the use of affordable and sustainable energy sources such as solar power and natural gas. Additionally, demand-side management strategies, like load following, help minimize peak-time energy costs and enhance efficiency. Furthermore, the model encourages investment in local energy infrastructure such as photovoltaic systems and natural gas pipelines networks, fostering economic opportunities like installing solar panel and distribution, job growth through technological innovation in energy efficiency solutions, and reduced dependency on traditional energy sources.

Noise Subspace Channel Estimation Algorithm for OFDM Systems

Kwame S Ibwe — Mon, 14 Apr 2025 00:00:00 +0000

In this paper, a novel blind channel estimator for Orthogonal Frequency Division Multiplexing (OFDM) affected by unknown impulsive interference is proposed. Unlike conventional subspace-based methods, this approach combines noise subspace decomposition with eigenvalue filtering to enhance interference suppression and improve channel estimation accuracy. The proposed technique ensures precise estimation of the covariance matrix, which is critical for reliable channel state information (CSI) retrieval. Moreover, by incorporating the presence of virtual subcarriers, the method further refines the estimation of channel response. Simulation results demonstrate that the proposed algorithm significantly outperforms existing subspace-based estimators, particularly in highly time-varying wireless channels and low signal-to-noise ratio (SNR) conditions. These findings confirm the practical applicability of the method in next-generation wireless networks like 5G and beyond, where robust and accurate channel estimation is essential for maintaining communication reliability under adverse conditions.

Exploring the Efficiency of Ceramic Water Filters towards the Removal of Selected Contaminants in Tanzania

Mon, 14 Apr 2025 00:00:00 +0000

The current study explores comparatively the efficiency of common ceramic water filters (CWF) in removing selected contaminants in water samples collected from rivers and ponds. Pot type (CWF1) and candle type (CWF2) ceramic water filters were purchased from the market to explore their efficiency towards removing organic matter, E. coli, turbidity, total suspended solids and colour in different retention times. The results on the quality of water from river and pond revealed that the levels of contaminants in water exceeded the standard set by TBS and WHO. The ability of CWF1 for organic matter removal in water from Kwakilosa river was 50% and Kalenga pond was 58%. On the other hand, the ability of CWF2 for organic matter removal in water from Kwakilosa river and Kalenga pond was 100%. E. coli removal for CWF1 was 84% for water from Kwakilosa river and 93% for water from Kalenga pond. For CWF2 dosing experiments E. coli removal efficiency was 100% for water from Kwakilosa river and 98% for water from Kalenga pond. In the third run, the CWF2 achieved a maximum E. coli efficiency removal of 100%. The study concluded that ceramic water filters that are found in Tanzania market are effective in removing specific water contaminants. However, CWF2 was more efficient than CWF1 due to the presence of activated carbon inside the filter. This study suggests that the ceramic water filters that available in the market should be modified to remove multiple contaminants.

From Waste to Wealth: Sisal By-product Opportunities in Tanzania

Neema Msuya, Abraham Temu — Mon, 14 Apr 2025 00:00:00 +0000

Sisal fibre production process in Tanzania is highly inefficient, utilizing only 2% of the plant leaving 98% waste including; damaged leaves, boles, roots, poles, decortication by-products and short fibres. These wastes contain valuable components like sugars, protein, volatile solids, carbon, and other organic matter, which can be repurposed into high-valuable products. This review examines the current state of sisal production and waste management in Tanzania, emphasising innovative strategies to transform sisal waste into valuable resources. While extensive research has identified potential products from sisal waste, such as acids, bioplastics, biofuels, or animal feed, commercialization efforts remain limited. The technical and economic barriers to commercialization include variability in waste quality and composition, as well as the initial costs of building the infrastructure and machinery needed to convert sisal waste into valuable products. It is essential to conduct comprehensive studies on the quantities and composition of sisal waste across Tanzania; the scalability of waste valorisation processes and marketing of the products from sisal waste. Such studies will enable informed decisions for specific policy changes, fostering industrial investments through collaboration between researchers, industry, and government. This will drive commercialization, unlocking its economic potential by creating new industries, job opportunities and reducing environmental impact.

Microplastic pollution in Farmland soils: A review on types, sources, analytical methods, environmental and human health risks

Emmanuel T Kato, Zainab J Katima, Rwaichi JA Minja — Mon, 14 Apr 2025 00:00:00 +0000

Microplastics (MPs) are emerging pollutants of growing concern in the environment. Initial studies on MPs occurrence, detection and risks have been extensively studied in the aquatic environment, far less of their occurrence and fate in agricultural ecosystems. Based on existing studies, this paper first focused on MPs types and sources. Secondly on the analytical approaches for soil MPs and emerging technologies. Furthermore, growing evidence of MPs threatening food security and human health was studied and risks posed by soil MPs to the environment and human health. Future research directions were outlined including standardized protocols for identifying and quantifying MPs, extensive human health risk assessment of soil MPs, synergistic and additivity effects of adsorbed chemical cocktails, the need for legally binding global legislation and a call for better management of plastic wastes for the sake of food security.

Analytical Hierarchy Process (AHP) based Safety Climate Maturity Model for building construction projects in Tanzania

Kamugisha J Kajumuloa, Juma M Matindana, Fatma K Mohammed — Mon, 14 Apr 2025 00:00:00 +0000

Tanzania's construction boom, while promising, casts a long shadow with its persistent safety challenges. Addressing these concerns requires not just reactive measures, but a proactive approach to cultivating a safety-mature construction environment. This research delves into this crucial aspect, proposing an Analytical Hierarchy Process (AHP)-based safety maturity model specifically tailored to Tanzanian building projects. MS Excel was used to create an Analytical Hierarchy Process by eight Safety and Health experts who tested the approach after the Smart PLS was used to identify important variables using factor reduction. Out of the 143 variables in the questionnaire, 19 factors were identified as essential factors to be used in this study using the Exploratory Factor Analysis (EFA). The general safety climate index (SCI) of 2.60 of the construction projects was determined. It indicated that the safety climate maturity of construction projects is in a compliant level because the range of SCI is within 2-3 (Level 3) indicating the safety climate processes and procedures are formal and defined. This research aspires to be a roadmap and guiding stakeholders towards safer construction sites, a thriving industry, and a brighter future where human well-being and project success go hand in hand.

Development of Fuzzy Analytical Hierarchy Process (FAHP)-Based Lean Manufacturing Maturity Criteria for The Tanzanian Context

Francis Daudi Sinkamba, Juma Mohamed Matindana, Mussa Mgwatu — Mon, 14 Apr 2025 00:00:00 +0000

The paper aims to develop Lean Manufacturing (LM) maturity criteria for assessing the level of LM implementation in Tanzania. The criteria will assist to determine LM maturity for manufacturing organizations in the country, which at the moment is not known. The study used survey and purposive sampling techniques to collect responses from 243 responses. Structured questionnaires and interviews were used in collecting responses from various respondents. Descriptive statistics through SPSS and the Fuzzy Analytical Hierarchy Process (FAHP) were used to analyze the data. The study has revealed the elimination of waste, continuous improvement, just-in-time, multifunctional teams, information systems, and zero defects as lean performance criteria for manufacturing industries in Tanzania. FAHP weights indicated that the criteria have different weights based on the level of manufacturing organizations. For micro industries, the FAHP weights of the criteria are the elimination of waste (0.2), continuous improvement (0.11), zero defects (0.26), just in time (0.31), multi-functional teams (0.04), and information systems (0.07). The FAHP weights can be used by the manufacturing organizations in setting strategies for improving the maturity level for each size of the manufacturing organizations. Improvement in maturity level will lead to improvement in organizational performance of manufacturing organizations. Better performance of manufacturing organizations will have positive contributions to the country’s Gross Domestic Product (GDP).

Fixed Point Results for β-ψ- φ Contractive Mappings in F-Metric Spaces with L-Fuzzy Mappings

Shabani Makwaru , Muhammed Raji, Marco Mpimbo, Yahaya Danjuma — Mon, 14 Apr 2025 00:00:00 +0000

In this paper, we explore the framework of -metric space, a well-known generalization of metric spaces, and establish fixed point results for - - contractive mappings in a complete -metric spaces endowed with L-fuzzy mappings. These additions broaden the body of knowledge in fixed point theory and fuzzy mappings. We showcase the practical applicability of our proposed results through illustrative examples and also, explore as an application, the solution for fuzzy initial-value problems.

Cysticercosis and Taeniasis in Humans, Pigs and Cattle: A Potential Extinction or Outbreak

Joshua A Mwasunda, Jacob I Irunde — Mon, 14 Apr 2025 00:00:00 +0000

Taeniasis and cysticercosis pose a health concern on both humans and animals, as well as the economy of livestock farmers in rural areas. This study examines cysticercosis and taeniasis transmission dynamics in human, pig and cattle populations. Both deterministic and continuous time Markov chain (CTMC) stochastic approaches are used. For deterministic and CTMC stochastic models, we used the next generation approach and the multitype branching process respectively to calculate the basic reproduction number and the stochastic threshold. The potential probability of cysticercosis and taeniasis extinction is computed through numerical simulations for the CTMC model using 10,000 sample paths and altering the initial values for classes that are infected. The findings demonstrate that when diseases’ outbreak occur, the CTMC stochastic model’s solutions resemble those of deterministic model quite closely. The findings also suggest that the likelihood of diseases’ extinction is high if they develop from a small number of taenia eggs. If the infections, however, emerge from humans with cysticercosis, they will perish. If the infections arise from either infected beef and pork or humans with taeniasis, there is a significant diseases’ outbreak in the human, pig and cattle populations. Therefore, at the beginning of a diseases’ outbreak, management strategies that concentrate on reducing taeniasis-infected individuals and consumption of infectious beef and pork can help in regulating the transmission of the diseases in humans, pigs, and cattle.

Potential Application of Silver Nanoparticles Synthesized Using Cassia abbreviata Aqueous Extracts in Water Treatment

Alex A Mlwisa, Andrea Rechenburg, Douglas Mushi — Mon, 14 Apr 2025 00:00:00 +0000

Nanotechnology is being recognized for its potential in addressing global drinking water issues, managing microbial risks, and meeting stringent water quality standards. However, there is a lack of information on the efficacy of silver nanoparticles synthesized using indigenous African herbal plants in eradicating harmful bacteria in contaminated water. This study introduces, for the first time, the use of the herbal plant Cassia abbreviata for the biosynthesis of silver nanoparticles. The biosynthesized silver nanoparticles were characterized using UV-vis spectrophotometer and atomic force microscope (AFM) techniques. The silver nanoparticles exhibited absorption peaks in the 400 to 500 nm range, with an average size ranging from 18 to 33 nm and a rough surface topography. These silver nanoparticles demonstrated potent antibacterial effects against both Gram-positive and Gram-negative pathogenic bacteria, regardless of whether the aqueous extract of leaves, stem barks, or root barks of C. abbreviata was utilized. The minimum inhibitory concentration (MIC) values for Gram-positive and Gram-negative bacteria ranged from <0.03 to 1.69 mg/mL. Additionally, the silver nanoparticles efficiently reduced high levels of fecal coliform bacteria (>10⁵ cfu/100 mL) in surface water to undetectable levels within 4 hours at a concentration of >9.37 mg/mL, showcasing their potential for water purification. Findings from this study demonstrate that aqueous extracts of C. abbreviata leaves, stem barks and root barks are excellent precursors for producing silver nanoparticles with robust antimicrobial and disinfectant properties

Environmental and anthropogenic variables influencing the distribution of the non-native tree species in Tropical Montane Forests of West Usambara, Tanzania

Martina B Hagweta, Henry J Ndangalasi, Samora M Andrew — Mon, 14 Apr 2025 00:00:00 +0000

A study to determine environmental and anthropogenic factors driving distribution of non-native tree species, Acacia melanoxylon and Eucalyptus grandis was conducted from January to March 2023 in Magamba Nature Forest Reserve (MNFR), West Usambara, Tanzania. Ninety-six (20 m x 20 m) plots were purposively set in which altitude, slope, soil, human disturbance indices and vegetation data were collected. Redundancy Analysis was employed to identify factors influencing the distribution of the non-native tree species in MNFR. The explanatory variables altitude, slope, human disturbance, soil organic carbon, pH, total nitrogen and bulk density were significant (p < 0.05) in influencing the distribution pattern of A. melanoxylon and E. grandis. Soil sand, silt, clay content, water content, available phosphorus and cation exchange capacity were not important (p > 0.05). The association between human disturbance and distribution of E. grandis recorded in this study implies that the MNFR faces serious human disturbances that need an urgent management response. We recommend more efforts to be directed towards the control of the human disturbances to circumvent encroachment of the tropical montane forests by non-native tree species. The findings of this study may be valuable for devising forest restoration programmes to sustain the ecosystem functioning in the West Usambara montane forests and similar ecosystems.

Rheological and Physicochemical Properties of Soy-Moringa Beverages: The Role of Xanthan Gum Stabilisation

Victor Vicent, Leonard Rweyemamu — Mon, 14 Apr 2025 00:00:00 +0000

The increasing demand for functional foods underscores the need to develop stable plant-based products. In this study, soy-moringa beverages with varying concentrations of xanthan gum were produced and stored at 4 °C for two weeks. During storage, rheological properties were analysed using a Brookfield rheometer, and assessments of physicochemical properties and beverage stability. The rheograms revealed that shear stress increased with the shear rate, while viscosity decreased by 92.31% in S₃ and 97.37% in S₄ as the shear rate increased. The Ostwald-de Waele model effectively described the flow behaviour of the soy-moringa beverage. Beverages enriched with xanthan gum exhibited shear-thinning behaviour (n < 1), whereas the control sample exhibited shear-thickening behaviour (n > 1) throughout storage. Significant increases (p < 0.05) were observed in moisture content (2.38%), ash content (32.95%), and total solids (28.80%) with increasing xanthan gum concentration. The results indicate that adding 0.3% to 0.5% xanthan gum enhanced the stability of the soy-moringa beverages during storage. Incorporating xanthan gum enhances the stability, texture, and shelf life of soy-moringa beverages, providing valuable insights for developing stable plant-based functional beverages.