Tanzania Journal of Engineering and Technology

Strategies for Overcoming Product Certification Challenges Faced by Food Manufacturing Small and Medium Enterprises in Tanzania

Ritha Matindiko — 2025-06-20

Small and Medium-sized Enterprises SMEs in Tanzania face significant regulatory challenges within bureaucratic, costly, and centralized environments. These challenges contribute to an increase in unregistered enterprises and substandard products in the market. This study aimed to address the challenges SMEs encounter in obtaining product certification to improve their product quality and market competitiveness. A mixed-methods approach was employed, combining qualitative and quantitative research through surveys, interviews, and document analysis, with respondents from the Tanzania Bureau of Standards TBS, Small Industries Development Organization SIDO, and SMEs in the food manufacturing sector. Data analysis was conducted using SPSS and JASP. Findings revealed that SMEs face challenges impacting market access 21.4, product quality 23.6, safety 19.9, and competitiveness 18.8. Confirmatory Factor Analysis CFA identified key latent variables influencing these factors, including market access 0.5, product quality 0.7, safety 0.4, and competitiveness 0.6. Additionally, the Delphi technique was employed to validate the findings, involving 10 knowledgeable and experienced respondents in the product certification process. To mitigate challenges hindering
product certification among SMEs, several strategies are proposed, including improving certification information

Prospects of Clean Cooking Energy in Africa - Transition Pathways and Implications

Joseph H. Kihedu — 2025-06-20

Despite abundant renewable energy resources, African countries still suffer from energy poverty, particularly in cooking. Up to 2022, about 74% of the African population had no access to clean cooking energy. With focus to Sub-Saharan African population, 90% has no access to clean cooking energy which decrease by 7% when kerosene is included. Traditional cooking, which involves the use of charcoal and firewood, is associated with health problems, environmental degradation, socioeconomic issues, and gender inequality. Transitioning to clean cooking energy not only promises significant health benefits but also offers opportunities for sustainable economic development and environmental preservation. In this study, the desk research method was used, which involved compiling raw published data such as research articles, government reports, implemented project reports, and published statistics. The following are the findings of this study: Firstly, for the improvement of health, environment, and social economic issues, the community must transition from traditional
cooking to clean cooking. Secondly, despite the promises posed by energy transition, upfront cost and technological challenges remain to be a challenge that need action. Thirdly, the government should weigh up on clean cooking technologies investment, program sustainability, and engaging the community. Lastly, the government should structure the clean cooking agenda based on the resource’s proportionality in the region. Generally, to improve the welfare of the community, energy transition from traditional to clean cooking stands as the main piece, however, the government should intentionally intervene for the
transition to be realized.

Analysis of an Improved Reliability Dual-Buck Structured Three-Level Flying Capacitor Inverter

Almachius Kamala Kahwa — 2025-06-20

With the increased demand for high-reliability power converters in the electric drive-train and propulsion systems, the efforts to design and analyze converters with high fault tolerance have become apparent. Among the emerging trends to improve the reliability of power converters is the incorporation of dual-buck (DB) structures in traditional converter topologies. Thus, this paper studies a single phase dual-buck structured three-level flying capacitor (FC) inverter. The dual-buck flying capacitor (DBFC) inverter was constructed in such a way as to suppress the shoot-through problems that may occur because of the switching mismatch and gate driver delay, as exhibited in the traditional FC inverter. The detailed operation of the DBFC inverter was performed using a comparative analysis of the traditional FC inverter as a benchmark. It was noted that the DBFC inverter considerably reduces the current stress on some switches and mitigates the shoot-through problem. Moreover, it was inferred that apart from improving the reliability of the inverter, the DBFC inverter reduces the total harmonic distortion (THD) of the output current. The 98.8% maximum efficiency and 4.03% THD were depicted in the DBFC at a switching frequency of 40 kHz. The results of the study were validated using detailed simulations and preliminary experiments.

Predicting the Influence of Aggregate Size and Distribution on Cementitious Concrete Properties: A Review

Mahamudu H. Mtebwa — 2025-06-20

Cement concrete has been in use for centuries as one of the primary construction materials. Its demand in the construction industry is expected to continue for several centuries before the full development of alternative products. However, one of the main areas of research interest is understanding how its constituents can be tailored to make its properties predictable to reduce risks associated with structural failures, reconstruction and reduced durability. These hindrances associated with cementitious concrete result from several attributes, including constituent material characteristics, mixing ratios and workmanship. Understanding the predictability of cement concrete properties requires computer modelling tools to provide reliable information for the mix design, construction, management and operation of cement concrete, and cement concrete structures. This paper reviews progresses in machine learning models for predicting cement concrete properties. Several algorithms have been reviewed, highlighting their applications, knowledge gaps and suggestions for future research. The paper provides a basis for selecting appropriate algorithms for predicting different concrete properties.

Development and Experimental Validation of a Non Invasive Blood Group Detection System

Nurath Kanule Nurudini — 2025-06-20

An individual's blood group consists of red blood cell antigens whose composition is determined by protein presence, antigen structure, and gene series. Persons aged above six months have significant anti-A and/or anti-B in their serum. During transplantation and transfusion, ABO blood group identification is the most essential factor. The conventional method involves drawing blood samples from patients, and the blood group is determined based on the antigen-antibody reaction. This method consists of adding chemical reagents. However, this requires time of operation, and throughput analysis is high, and the process is also challenging to interpret. Accurate and rapid identification of blood groups is therefore crucial in various medical fields, including blood transfusions, organ transplants, and prenatal care. Traditional methods for blood typing often require extensive laboratory equipment and trained personnel, leading to delays and potential errors in critical situations. This research focuses on developing a non-invasive, compact, and user-friendly device capable of determining blood groups quickly without invasively collecting patient’s blood samples and using reagents. The system learns from a database of annotated blood samples by employing machine learning algorithms, enhancing its accuracy and reliability over time. A non invasive blood group detection system was verified experimentally on a laboratory prototype, achieving an accuracy of 95.9% in identifying blood groups and rhesus factors. Furthermore, a comparative analysis was conducted between the proposed system and existing counterparts. This analysis demonstrated that the proposed system outperforms others in accuracy, indicating the rhesus factor.

Comparative Analysis of the Efficiency of Reverse Osmosis and Hydroxyapatite for Fluoride Removal in Water: A Case of AUWSA

Innocent J. Macha — 2025-06-20

Water treatment technology selection depends on contaminant type and budget. Fluoride removal from water is particularly challenging, requiring non-conventional treatment technologies (Radwan, 2023). Several regions in Tanzania, including Arusha City, are affected by fluoride contamination. With a population of 617,631 (Census, 2022), only 117,763 people currently have access to clean water supplied by AUWSA. This study aimed to compare the efficiency of Reverse Osmosis (RO) and Hydroxyapatite (HAP) in fluoride removal as a strategy to address water quality and supply challenges. Experiments were conducted using 6 m³ of raw water with fluoride concentrations ranging from 5.1 mg/L to 6.83 mg/L, sourced from boreholes. The HAP pilot plant was tested at 30-minute intervals from 8:00 AM daily for 21 days, while the RO system was tested with the same water volume at 5-minute intervals over the same period.
Laboratory analyses of raw and treated water revealed that HAP had a lower fluoride removal efficiency of 91.51% to 93.41%, compared to RO, which achieved 96.05% to 97.66% removal efficiency. It was also revealed that RO loses about 30% of water during treatment, while HAp doesn’t lose any. Moreover, HAp uses locally available biogenic materials for treatment, enhancing sustainability. The findings suggest that the HAP treatment system is a practical and sustainable solution, offering effective fluoride removal while remaining affordable and energy-efficient, making it a viable choice for communities in need of clean and safe drinking water. This research addressed the problem of excess fluoride concentration in water and availability and access of clean water. Further research is recommended to evaluate the environmental implications of waste disposal following HAP media regeneration and the management of reject water from the RO filtration process. This assessment should focus on potential ecological risks, long-term sustainability, and the development of environmentally
friendly disposal or reuse strategies.

A Review of Lithium-ion Battery Capacity Fade Deceleration at Power Fluctuations in Renewable Energy Systems

Isaac Gwayi — 2025-06-20

Application of lithium-ion (Li-ion) batteries to store energy in renewable energy systems (RESs) is increasing due to their promising properties. Therefore, it is crucial to understand aging behaviours of Li-ion battery during RES life time as this directly affects cost of energy. Li-ion battery aging can be categorised into calendar aging and cycle aging. Calendar aging depends mainly on temperature and state of charge (SoC). In addition to temperature and SoC, cycle aging depends also on charge and discharge current rates and cut-off voltages. Higher current rates lead to faster Li-ion battery aging. It is necessary to identify appropriate battery power control strategies and their configuration to decelerate batteries’ aging in RESs. In this paper, a review of effects of power fluctuations on cycle life of Li-ion batteries in RESs has been done. Furthermore, hybrid energy storage systems (HESS), comprising battery system (BS) and supercapacitor (SC), topologies and control strategies are studied. Literature focussing on BS-SC systems in RESs was reviewed aiming at finding commonly used topologies and strategies. It has been found that the most commonly used methods in BS-SC HESS are classical strategies (70%) and full active converter topology (80%). The study recommends using classical control strategies and full-active converter topology during BS-SC implementation in RESs.Furthermore, the study recommends that future research should focus on evaluating in detail technical and economic factors of the identified control strategies and HESS
converter configurations.

Optimizing the Processing Temperature for Synthesis of Silver Nanoparticles within Cellulose-Wool Keratin supramolecular Matrix using Butylmethylimmidazolium Chloride Ionic Liquid

Ngesa Ezekiel Mushi — 2025-06-20

To date, the synthesis of silver nanoparticles on the surface of cellulose and wool keratin biopolymer, while dissolved in ionic liquid, is attractive because of its biomedical potential. However, the optimal processing temperature for the nanoparticle formation is unclear. The previously reported temperature of approximately 120°C gives unpredictable results. The current study employs a combination of 50% cellulose and 50% keratin, along with 69 mg of silver chloride, in Butylmethylimidazolium Chloride BMImCl ionic liquid, using a single pot process to produce a supramolecular film via non-derivatized mechanochemical interactions. The primary objective is to experimentally establish the processing temperature to achieve stable growth of metallic silver nanoparticles. The synthesis was conducted by heating the ionic mixture at temperatures of 110°C, 120°C, and 130°C. The study observed that raising the temperature to around 130ºC for 5 min is more practical. Moreover, though this data is higher, it does not compromise the thermal stability of cellulose and keratin's structure. The structural properties of the nanoparticles have been confirmed using Fourier transform spectroscopy (FTIR) and scanning electron microscopy (SEM). Furthermore, energy-dispersive X-ray spectroscopy (EDS) and powder X-ray diffraction (XRD) provide valuable insights into the physical characteristics of the produced silver nanoparticles, with a diameter of around 8.5 nm, and are uniformly distributed in-plane within the matrix. While the underlying mechanisms remain uncertain, they likely involve anchoring ionic silver onto the wool keratin while dissolved within the ionic liquid at elevated temperatures before reducing to metallic silver at room temperatures. Besides being sustainable, this green approach enhances understanding of the possibility of creating stable silver nanoparticles within the supramolecular matrix, which is essential for future applications in the biomedical field.

Assessment of Maintenance Performance Level of Selected Hydropower Plants in Tanzania

Mahamudu Hussein Mtebwa — 2025-06-20

Despite significant progress in increasing electricity access to over 78%, electricity reliability in Tanzania remains a concern, with frequent power outages reported. Maintenance issues in hydropower plants have been identified as a critical factor contributing to this problem. However, the specific maintenance performance levels have not been fully assessed. This study conducts a comprehensive evaluation of the maintenance performance of four key hydropower
plants: Kidatu (204 MW), Kihansi (180 MW), Mtera (80 MW), and New Pangani Falls (68 MW). Data collected from staff surveys and maintenance records between 2018 and 2022 were used in the study. Although staff demonstrated a reasonable awareness of the hydropower plants Key Performance Indicators (KPIs), with a minimum mean score of 3.66, the findings reveal underperformance across all plants, with a heavy reliance on reactive rather than
proactive maintenance. Low plant availability (89%), insufficient planned work (42%), and excessive unplanned work (55%) were recorded. High Mean time to Repair and frequent failures, particularly at New Pangani Falls, were also observed. This research underscores the importance of strategic maintenance improvements to enhance the reliability and efficiency of Tanzania's hydropower sector.

Evaluation of Thermal and Emission Performances of Briquettes Produced from Carbonized Corn Cob and Corn Husk

Karina Sultane Motani — 2025-06-20

The Mozambican agro-industrial sector relies heavily on various crops, with maize being the most significant. During processing, substantial waste is generated, which is often discarded as organic matter or burned, contributing to environmental pollution and the loss of potential energy resources. This study evaluated the thermal and emission performance of briquettes made from carbonized corn cob (CCC) and carbonized corn husk (CCH), using cashew nut skin as a binder for clean cooking applications. The briquettes were assessed against firewood and charcoal as control fuels, focusing on several energy performance parameters: water boiling time (WBT), combustion index (CI), thermal efficiency (TE), and emissions (E). Testing was conducted using an improved combustion stove (burnjikokoa). Results indicated a CI of 1.06±0.04 for carbonized corn cob briquettes (BCCCNS) and 1.14±0.03 for carbonized corn husk
briquettes (BCHCNS). The WBTs (in minutes) were 17 for BCCCNS, 29 for BCHCNS, and 45 for both firewood and charcoal. Thermal efficiency was notably higher for BCCCNS (45%) and BCHCNS (42%) compared to charcoal (24.13%) and firewood (21.55%), suggesting that the selected waste materials are excellent for producing high energy briquettes. In terms of emissions, particulate matter (PM2.5) levels were measured at 80 µg/m³ for both BCCCNS and BCHCNS,
while firewood produced 190 µg/m³ and charcoal 120 µg/m³. Carbon monoxide (CO) levels were all below 200 ppm. These findings demonstrate the potential of utilizing agro-industrial waste to create sustainable and efficient cooking fuels.

The Royal Academy of Engineering, UK and The Enriching of Engineering Education Training and Practice Programme in Sub-Saharan Africa

Bavo B. Nyichomba — 2025-06-20

This paper elucidates initiatives taken by the Royal Academy of Engineering, UK, to overcome barriers in education and training in Sub-Sahara African higher learning engineering institutions. The said barriers include mismatches of curriculum, ineffectual teaching and learning and little exposure of academic staff to engineering practice. In order to overcome such barriers, the Royal Academy of Engineering established the two programmes in the region. The first one, Enriching Engineering Education Programme (EEEP) from 2014/15 to 2015/16 where the University of Dar es Salaam coordinated this programme as a hub for East African universities namely; Makerere University (Uganda), Moi University (Kenya), Dedaan Kimathi (Kenya) and Kenyatta Technical University (Kenya). A second programme which was implemented from 2015/16 to 2023/24, the University of Dar es Salaam also acted as a Hub for the local higher learning institutions namely; the Dar es Salaam Institute of Technology, Nelson Mandela, Mbeya University of Science and Technology, Sokoine University of Agriculture and National Institute of Transport under the new Higher Education Partnerships programme in Sub-Saharan Africa (HEPSSA); leaving Moi University and Makerere also to coordinate their own local universities under HEPSSA programme. All the above programmes involved capacity building in enhancing the outcome based curriculum, problem-based learning, academia and industry staff exchange, student placements in industries, and technology business incubators/hubs practices. Conversely, the paper emphasizes the need establishing concordats of universities that will enhance collaboration of universities with industries in establishing joint research and development programmes for practical applications to technical and business problems facing the industry/private sector and the nation as a whole.

The Impacts of Renewable Energy Sources: A Review on Grid Inertia and Frequency Regulation

Sospeter Gabriel — 2025-06-20

The power system is gradually transitioning into low inertia due to integrating substantial intermittency quantity of converter-based renewable energy sources, such as wind and photovoltaic power, into the current power grid network. This integration presents significant inertia and frequency control challenges to the network as a result of a decrease in the percentage of synchronous generators. Moreover, faster frequency deviations are posed by the mismatch between the supply and demand during contingencies, which creates difficulties in preserving the frequency stability of the power system. This research explores the impacts of renewable energy sources (RESs) on grid inertia and frequency management as key parts of preserving the power system's stability. Furthermore, the research article proposes mitigation ways to optimize both conventional synchronous generators and synthetic inertia for consistent and dependable functioning of the grid network while accommodating a growing share of renewable energy. The mitigation measures examined in this review research paper are synthetic inertia, fast frequency response, and battery storage systems.

Towards Metrology 4.0 in Developing Countries’ Manufacturing Industries

Jailos Mrisho Nzumile — 2025-06-20

A systematic literature review was conducted to unveil the status of the digital transformation of metrology in developing countries, as they are lagging in utilising fourth industrial revolution (IR4.0) technologies to transform manufacturing industries. A PRISMA technique was employed using various keywords to identify, screen, and select the relevant literature. Forty publications were selected for the review, mainly discussing IR 4.0 technologies in metrological operations. The results indicate that the digital transformation of metrology has yet to be initiated in developing countries. However, the employment of IR4.0 technologies in advancing metrological operations in manufacturing industries is mostly discussed in the literature, especially in China and India. It was also evident that African countries lag behind their Asian counterparts in utilising the IR4.0 technologies to advance metrological operations in manufacturing industries. To enable sustainable digital transformation in metrology, national measurement institutes, testing and calibration laboratories, and manufacturing industries should embrace utilising IR 4.0 technologies in metrological operations. This will facilitate coordination and harmonisation of metrological operations within the three entities, eventually leading to sustainable digital transformation in metrology. The transformation in developing countries will enable precision, high-quality, and accurate metrological operations in manufacturing industries, leading to increased product quality and industry competitiveness in the international market. Also, industries could save time and cost while reducing errors in performing metrological operations. Moreover, the description of the phases that the manufacturing industries could go through towards Metrology 4.0 is also provided.

Mitigation of Voltage Disturbances in Industrial Power Distribution Networks Using Dynamic Voltage Restorers

Godwin E. Mnkeni — 2025-06-20

Most electrical and electronic equipment in industries require high quality power to function efficiently. Nonetheless, voltage sags and swells are pressing concerns and prone to directly impact the economy of industrial customers. One such customer embattled with these problems is Mbeya Cement Company Limited (MCC) located in Mbeya, Tanzania. These issues mainly are caused by upstream faults and switching operations. One way to address these is by utilizing the voltage injection method, which employs a power device known as a dynamic voltage restorer (DVR). In this paper, the voltage sags and swells of balanced three-phase, unbalanced double-line and single-line to ground faults are studied. Thereafter, mitigation strategies using the DVR are proposed for the MCC. A section of the MCC power distribution network fed from Tanzania Electric Supply Company Limited (TANESCO) Mwakibete substation with a 33 kV feeder is modeled using MATLAB/Simulink environment to mitigate the disturbances (sags/swells). The percentage of voltage sags and swells logged from the industrial feeder are 11 and 115%, respectively. To effectively utilize the DVR device, a control strategy is designed in the d-q-o reference frame, whereby the scaled errors between the source side of the DVR and its references for sags/swells corrections are considered. Simulation results revealed that the DVR performance handles both balanced and unbalanced voltage sags and swells by injecting the appropriate voltage to the supply, therefore, maintaining
the load voltage at its nominal value. It can be concluded that the DVRs are recommended to be incorporated into the MCC feeders to mitigate the upstream disturbances. However, DVR performance comes at the cost of energy storage and DVR transformer rating. Further studies are encouraged to focus on the DVR performance optimization and cost implications.

Towards Future Sustainable Infrastructure: The Role of Technical Audit in Tanzania’s Public Works

George C. Haule — 2025-06-20

This study aimed to investigate the vital role and impact of technical audits in promoting sustainable infrastructure development in Tanzania. The role and effects of technical audits in long-term infrastructure development were studied using a mixed-methods approach with both quantitative and qualitative parts. Data were collected through analysis of technical audit documentation, a semistructured questionnaire, and stakeholder interviews. The study revealed the various dimensions of infrastructure investment projects, including initiation and planning, design, procurement of contractors and consultants, contract management, environment, health, and safety. The technical audit findings reported weaknesses or nonperformance issues in infrastructure planning at the national level and in infrastructure projects, programs, and portfolios at various stages of their lifecycle that need to be addressed. The implementation of
governance approaches aims to address environmental, social, and economic impacts and achieve investment objectives. The audited entities received recommendations for improvements to address non performance issues. Furthermore, the timely implementation of these recommendations significantly contributed to the achievement of infrastructure development objectives. Based on the findings, the research concluded that technical audits play a significant role in promoting sustainable infrastructure development in Tanzania. The study recommended strengthening the institutional capacity of organisations overseeing technical audits by investing in training programs, professional development initiatives, and knowledge sharing platforms. These initiatives will help to improve the technical expertise and competency of auditors and project stakeholders, who will consequently benefit from the technical audit of infrastructure development.

Comprehensive Review of Sensible Thermal Storage Systems for Cooking Applications

Anna K. Sharishoy — 2025-06-20