Digital Commons Network^™

Integrating Gis With Interim Payment Valuation In Road Construction Projects: A Conceptual Framework, Abdulrahman I. Iro, Juma M. Matindana, Julian Ijumulana

Tanzania Journal of Engineering and Technology (TJET)

Abstract

Interim Payment Valuation is a critical process in road construction contract administration, yet conventional valuation practices remain heavily dependent on manual measurements, fragmented documentation, spreadsheets, and professional judgement. These limitations can affect measurement accuracy, transparency, traceability, and the timeliness of payment certification. Although Geographic Information Systems have increasingly been applied to construction planning, quantity measurement, progress monitoring, infrastructure management, and decision support, their integration with contractual and financial processes for interim payment valuation remains insufficiently explored. This study therefore develops a conceptual framework for integrating GIS with Interim Payment Valuation in road construction projects. A PRISMA-guided structured literature review …

Artificial Neural Network-Based Modelling And Prediction Of Key Performance Indicators In Road Construction Projects, Hussein Mativila, John M. Kafuku, Beatus A. T. Kundi

Tanzania Journal of Engineering and Technology (TJET)

Road construction projects in developing countries including Tanzania experience several challenges including cost overruns, schedule delays and poor quality. The causes of these challenges include complex interdependencies project’s uncertainty factors. This makes traditional methods for predicting Key Performance Indicators (KPIs) less effective. This study has developed a robust Artificial Neural Network (ANN) model for accurate modelling and predicting KPIs for road construction projects in Tanzania. The analysis was based on data obtained from 281 projects implemented by TANROADS in 11 regions from 2015 to 2025. Fourteen uncertainty factors were measured on a five-point Likert scale and screened using Principal Component …

Voltage-Related Power Quality Issues And Impacts On Distribution Networks With Sensitive Loads - A Review, Godwin Elinazi Mnkeni, Jackson Justo, Aviti Thadei Mushi, Bakari M. M. Mwinyiwiwa

Tanzania Journal of Engineering and Technology (TJET)

Voltage disturbances are the most important power quality (PQ) complications that customers and power utilities face in this smart era. The growing adoption of sophisticated electronic equipment and integration of renewable energy sources (RES) into power grids has increased the susceptibility of power distribution networks (PDNs) to voltage sags, swells, interruptions, flicker, and voltage imbalance. These disturbances, mainly caused by upstream faults, switching operations, and RES integration, compromise voltage PQ and system reliability. Consequently, they accelerate equipment degradation, increase electronic waste (e-waste), raise reactive power demand and maintenance costs, increase power losses, and impose substantial economic losses on customers and …

Exploring Consultancy-Related Variations In Public Building Projects: A Review Towards A Management Framework, Grayson Bambaza, Ismail W. R. Taifa, George S, Mwaluko

Tanzania Journal of Engineering and Technology (TJET)

Consultancy-related variations remain one of the leading causes of cost overruns, schedule delays, quality deficiencies, and contractual disputes in public building projects. Although various studies have been undertaken to document the causes of variations in construction works, the same level of interest has not been shown for consulting services variations across the consulting services spectrum and their consequences for effective management. This study explores variations in consulting services for public works by systematically reviewing the existing literature using the PRISMA (Preferred Reporting Items for Systematic reviews and Meta Analyses) guidelines. Relevant articles published from 2020 to 2026 were retrieved from …

Urban Spatial Development Control In Tanzania: Analysis Of Factors Influencing Gis Application Using Structural Equation Modelling (Sem)., Happiness Protas Mmanda, Nestory Yamungu

Tanzania Journal of Engineering and Technology (TJET)

Rapid urbanization in developing countries has intensified urban expansion, creating challenges for sustainable development. Geographic Information Systems (GIS) enhance spatial planning, but empirical evidence on factors influencing their effectiveness remains limited. This study examines determinants of GIS application in Urban Spatial Development Control (USDC). The objectives are to (1) identify and categorize factors affecting GIS use, (2) assess relative strength, and (3) develop a validated structural model explaining GIS adoption in USDC. Data were collected from 103 LGAs by a mixed sampling method. Exploratory and Confirmatory Factor Analysis classified influencing factors into technology-related (α = 0.869, CR = 0.881), process-related …

Decision Support Tool For The Maintenance Of Meter Gauge Railway Permanent-Way Infrastructures: A Concept Paper, Hamisi J. Maulid, Beatus A.T Kundi, Juma M. Matindana, Ismail W. R. Taifa Dr

Tanzania Journal of Engineering and Technology (TJET)

A Decision Support Tool (DST) represents a transformative way of modernising maintenance practice on the permanent-way infrastructure of Meter Gauge Railway (MGR). Maintenance practice remains largely reactive, as the MGR plays a strategic role in transporting both freight and passengers, resulting in inefficient resource allocation, high operational risk, and growing Lifecycle expenses. This concept paper explores the potential and the design challenges for a DST that combines fuzzy analytic hierarchy process (Fuzzy-AHP) modelling, multi-criteria decision analysis (MCDA), Geographic Information Systems (GIS) and predictive machine learning (ML) analytics for evidence-based, future-oriented maintenance management. The paper draws on peer-reviewed studies from …

Optimization Of Gas Consumption, Cost And Production Rate For Computerized Numerical Control Oxy-Acetylene Flame Cutters, Eustace K. William, Simon I. Marandu, Enock W. Nshama

Tanzania Journal of Science

This study examined the impact of flame cutting parameters (i.e., cutting speed, plate thickness and nozzle diameter) on oxy-acetylene gas consumption, cost and production rate. A full factorial design of experiments was used to generate 27 experiments, which were conducted using a CNC flame cutter. The analysis of variance (ANOVA) method was used to determine significant process parameters, followed by regression analysis using the MINITAB ® software. The technique for order preference by similarity to ideal solutions (TOPSIS) was used to determine the optimal cutting parameters for minimizing the consumption and cost estimation of oxy- acetylene gas and maximizing the …

Compact Low-Profile Dual-Band Microstrip-Fed Monopole Antenna For Wlan And Lte Applications, Hashimu U. Iddi

Tanzania Journal of Engineering and Technology (TJET)

The rapid advancement in wireless communication technologies has led to rising user demand for high-speed data transfer, seamless connectivity, and improved wireless communication efficiency. Therefore, it is inevitable to develop efficient and compact antennas which can support different frequency bands of various wireless system standards in mobile devices. A compact, low-profile microstrip-fed monopole antenna operating in dual bands, 2.45 GHz and 5.8 GHz, and suitable for WLAN and LTE applications is proposed in this study. The proposed antenna’s radiating element was carefully designed using slotting techniques and optimising the various parameters for achieving the required resonance frequency. The proposed compact, …

Enhancing Community Engagement Through ‘Nitunze Kilombero’ Mobile App: Case Of Climate Land Use And Cover Management For Kilombero Basin, Ghanima Chanzi, Subira Munishi

Tanzania Journal of Engineering and Technology (TJET)

The Kilombero Basin in southeastern Tanzania faces significant challenges due to rapid land use and land cover (LULC) changes driven by climate change, population growth, and unsustainable farming practices. This study assessed the role of community engagement and digital reporting through the 'NITUNZE KILOMBERO', mobile application in supporting water resources management in the basin. The App facilitates real-time reporting of environmental issues, provides educational resources, and enables collaboration between local communities and authorities. A mixed-methods approach, including household surveys and key informant interviews, was employed to assess the app's effectiveness. Results indicate high community awareness of LULC impacts, with 85% …

Load Flow And Fault Performance Evaluation Of Interconnected Minigrids In Uganda Using Digsilent Powerfactory, Prossy Mutesi, Santos Kihwele, Emmanuel Matee

Tanzania Journal of Engineering and Technology (TJET)

The increasing demand for decentralized, reliable electricity in rural Sub-Saharan Africa has catalyzed the deployment of minigrids as an intermediate electrification strategy. This study investigates two solar photovoltaic (PV) mini-grids: Kyamugarura and Kanyegaramire, located in western Uganda, approximately 3km apart. Each mini grid initially consisted of 13 kW installed photovoltaic (PV) capacity, supplying power to households and small businesses. Due to rising demand and regular evening blackouts, both mini-grids are being upgraded to 57 kWp each. The integration of these upgraded systems into the national utility grid is proposed and simulated to evaluate performance improvements under two medium-voltage interconnection options: …

A Review Of Energy Storage Technologies With Hydro Energy System Design For Off-Grid Electricity, Daniel H. Ngoma, Banet L. Masenga

Tanzania Journal of Engineering and Technology (TJET)

Many renewable energy sources such hydropower—particularly small-scale run-of-river and micro-hydro—offers reliable, low-cost generation. However, their inherent intermittency (due to seasonal flow variations) and inability to instantly match demand necessitate integrated energy storage to ensure a stable, continuous power supply. This review synthesizes contemporary energy storage technologies in the context of their integration with off-grid hydro energy system design.

The study examine a spectrum of storage solutions, evaluating their technical characteristics, costs, and suitability for hybrid hydro applications. Pumped Hydro Storage (PHS), while highly efficient and large-scale, is often geographically constrained and capital-intensive for small off-grid projects. Battery Energy Storage Systems …

Revitalising Tanzania’S Textile Industry Through The Uk Textile System’S Role, Charles M. Kahabi

Tanzania Journal of Engineering and Technology (TJET)

Currently, there is the environmental and social challenges emerging from the global clothing and textile industry, specifically on textile waste management.  Additionally, the flow of second-hand clothing (SHC) between European countries especially the UK and Tanzania is increasing. In the UK, rapid growth of second-hand clothing (mitumba) driven by fast fashion results in vast quantities of discarded garments, of which only a fraction is recycled, leaving the remainder in landfills. Conversely, Tanzania has long depended on imported SHC a practice that, while affordable, has undermined local textile industries and contributed to waste accumulation. By examining Tanzania’s textile landscape, the research …

Optimization Of Vehicle Mix For Three-And Four-Wheel Passenger Transportation System In Nigeria, Omotunde A. Muyiwa, Hamid A. Jimoh, Kolawole T. Oriolowo

Tanzania Journal of Engineering and Technology (TJET)

Efficient transportation systems are essential for reducing passengers waiting times in densely populated areas. However, there is a dearth of information on the optimization of vehicle mix for three-and four-wheel transportation systems in Nigeria. The present study was designed to optimize the vehicle mix for three-and four-wheel passenger transportation to improve transportation efficiency. Twenty purposively selected vehicles were observed, while a queuing model (M/M/s) was used to determine passenger arrival rates during different periods (morning, afternoon, and evening). An integer linear programming model was developed to minimize passenger waiting times. Data on vehicle types, capacities, travel cycles, and average passenger …

Implementation Of The Fourth Industrial Revolution Technologies In Tanzania’S Downstream Oil And Gas Industries, Vitalis John Mwinyi

Tanzania Journal of Engineering and Technology (TJET)

The advent of the fourth industrial revolution (IR4.0) has resulted in the digital transformation of multiple sectors of the economy due to the disruptive nature of the technologies driving the revolution. The technologies have already found their way into the oil and gas industries across the globe, especially in upstream, midstream, and downstream operations. However, the degree of implementation is not the same for these operations, considering the complexities involved, integrated process, the associated risk and investment cost, among others. This study aimed to establish the implementation level of IR4.0 technologies in the downstream operations. A survey method was employed …

Analysis Of Factors Enabling Organisational Governance Maturity For The Technical Audit Function In Tanzania, George C. Haule

Tanzania Journal of Engineering and Technology (TJET)

The study aimed to identify key factors contributing to Organisational Governance Maturity (OGM) of the Technical Audit Functions (TAF) in Tanzania.  The study employed a sequential approach as a research design.  The first step was to collect and analyse literature studies to identify factors enabling the OGM of the TAF.  Next, a questionnaire was administered to one hundred twenty-eight (128) respondents from seven (7) TAFs to rank the key enabling factors that were identified from the literature that influence the OGM of TAF in Tanzania.  Using data from a questionnaire administered to 128 respondents, a two-step strategy was employed to …

Multi-Objective Optimization Of Waste Incineration For Minimal Carbon Monoxide And Sulfur Dioxide Emission And Rate Maximization: A Case Study Of Mbezi, Mkuranga-Pwani, Tanzania, Grangay M. Nyanghura, Enock W. Nshama

Tanzania Journal of Science

Incineration is widely employed for hazardous waste disposal, but results in harmful flue gas emissions. This study optimizes a double-chamber incineration process to reduce sulfur dioxide (SO2) and carbon monoxide (CO) emissions while maximizing the incineration rate. The effects of waste mass, primary chamber temperature (PT), and secondary chamber temperature (ST) were analyzed using a full factorial design of 27 experiments. ANOVA revealed that mass had the greatest impact on emissions and incineration time, ST had a moderate effect, and PT had little influence. Regression analysis provided models for incineration time, CO, and SO2 emissions. Single-objective optimization using sequential quadratic …

Design Of A Sequential Logic Control System For Water Recycling In Car Wash Operations For Minimising Utility Costs, Enock W. Nshama, Mussa Iddi Mgwatu

Tanzania Journal of Engineering and Technology (TJET)

The car wash sector in Tanzania is expected to expand in the next few years, since the trend of imported cars is increasing. However, the traditional method of washing cars is subjected to water overuse and environmental pollution. This study presents a design of water recycling sequential logic control system to come up with a cost-effective car wash operation aimed at effectively utilising water and electricity resources. Data were collected at 78 car wash stations in Dar es Salaam region to determine water and electricity costs. Data were analysed using MS Excel and Minitab to establish the trend of utility …

Techno-Economic Analysis Of Captive Solar Power Systems For Tanzania’S Manufacturing Sector: Barriers, Opportunities, And Feasibility, Edson Uhale, Sarah P. Ayeng'o

Tanzania Journal of Engineering and Technology (TJET)

This study provides a comprehensive techno-economic analysis of the barriers, opportunities, and feasibility of adopting captive solar photovoltaic (PV) systems in Tanzania’s industrial manufacturing sector. Despite Tanzania’s high solar irradiation potential, averaging 4.5 to 7.0 kWh/m²/day, the uptake of captive solar systems remains minimal, with only 2.3 percent of surveyed firms currently using solar energy, primarily for non-productive uses such as security lighting. Using a mixed-methods approach, data were collected from 43 manufacturing firms in the Dar es Salaam and Pwani regions through structured questionnaires, supported by PVSyst simulations and financial modelling to assess two system configurations: grid-connected PV systems …

Optimization Of Welding Parameters For Carbon Steel Fabrication: A Trade-Off Between Tensile Strength And Heat-Affected Zone, Melkiory B. Njawala, Simon I. Marandu, Enock W. Nshama

Tanzania Journal of Engineering and Technology (TJET)

This study focused on optimizing gas metal arc welding (GMAW) parameters for AISI 1045 carbon steel to balance the ultimate tensile strength (UTS) and heat affected zone (HAZ) size of the weldment. Using a full factorial design of experiments (27 trials), the influence of welding current, arc voltage, and travel speed on UTS and HAZ size of AISI 1045 carbon steel weldments were investigated. From the analysis of results, using Analysis of variance (ANOVA) technique, the results revealed that current, travel speed and arc voltage contributed 74.41%, 19.05% and 0.04%, respectively, to the total percentage of variations on UTS data. …

Combined Optimisation Of Machining Parameters, Tool Wear, Dimensional Errors And Quality Deviations In Multi-Pass Turning Operations, Mussa I. Mgwatu

Tanzania Journal of Engineering and Technology (TJET)

Measurements of on-line tool wear and part dimensional accuracy in machining operations are not readily available in machining shop floor because they involve higher investment such that the decisions of tool wear and part quality for intermediate cutting passes cannot be justified. This paper demonstrates how the optimisation of machining parameters can be made together with tool wear and part quality for turning operations. Two optimisation models were developed for maximum material removal rate and minimum production cost. A theoretical framework was initially presented before the two models were formulated. Input data for the models were adopted from previous studies …

Condition Optimization For The Synthesis Of Castor Oil Templated Mesoporous Silica, Godlisten Namwel Shao

Tanzania Journal of Engineering and Technology (TJET)

The present work provides suitable conditions for the synthesis of mesoporous materials with improved porosity using an optimization technique. The proposed preparation method involves forming final products by varying the amount of castor oil, media, and template removal. The obtained samples were examined by TGA, XRD, DRIFT and nitrogen physisorption studies. It was observed that the porosity of the obtained samples was dependent on the conditions under which the materials were synthesized. All synthesized materials showed the Type IV adsorption-desorption isotherm features of mesoporous, regardless of the conditions utilized during the synthesis. The sample synthesized using 2.5 g of a …

Adoption Of Agrivoltaics In Developing Countries: A Review On Challenges, Opportunities And Future Prospects, Abdi J. Athumani, Pater Makolo

Tanzania Journal of Engineering and Technology (TJET)

This paper provides a review of agrivoltaics technology and how it has been applicable in developing countries, including African countries. Agrivoltaics, the integration of agricultural production with photovoltaic energy generation, offers promising solutions to water- energy-food nexus in developing countries. This technology offers the dual benefit of increasing agricultural productivity while generating clean energy, which is very important for regions facing frequent electricity shortages and declining agricultural yields due to climate change. However, despite its potential, the adoption of agrivoltaics in developing nations remains limited in comparison to developed countries due to financial, technical and policy constraints. This paper explores …

Cnn-Based Hybrid Model For Detecting Blight Diseases In Potato Crops With Advanced Image Processing Techniques, Farian S. Ishengoma

Tanzania Journal of Engineering and Technology (TJET)

Potato production plays a vital role in global agriculture as a major food source for large populations. However, potato crops are highly susceptible to diseases, particularly Early Blight and Late Blight, which result in substantial yield losses. Timely detection and effective control of these diseases are essential for maintaining stable crop output. This study explores the integration of Convolutional Neural Networks (CNNs) and advanced image processing techniques to differentiate between diseased and healthy potato plants accurately. Two datasets comprising original and enhanced images were used to train four CNN models: InceptionV3, Xception, Densenet201, and Resnet152V2. The original images underwent background …

Comparative Analysis Of The Efficiency Of Reverse Osmosis And Hydroxyapatite For Fluoride Removal In Water: A Case Of Auwsa, Innocent J. Macha

Tanzania Journal of Engineering and Technology (TJET)

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, …

The Royal Academy Of Engineering, Uk And The Enriching Of Engineering Education Training And Practice Programme In Sub-Saharan Africa, Bavo B. Nyichomba

Tanzania Journal of Engineering and Technology (TJET)

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), …

Performance Dynamics Of Activated Carbon-Methanol Pair In Adsorption Refrigeration Systems, Ibrahim J. Mwasubila

Tanzania Journal of Engineering and Technology (TJET)

Adsorption refrigeration systems have shown potential for addressing the adverse effects of traditional compressor-based refrigeration systems. Adsorption refrigeration systems that utilise activated carbon and methanol demonstrate good performance, especially at temperatures below 0 °C. This combination significantly improves the cooling performance of the system, making it a dependable option for freezing applications. Despite having the potential to meet cooling demand and be eco-friendly, the adsorption refrigeration system has several drawbacks that hinder its commercialisation. This paper discusses the properties of the activated carbon methanol pair in the adsorption refrigeration system. The focus is on the desorption temperature, thermal stress, repeatability …

Strategies For Overcoming Product Certification Challenges Faced By Food Manufacturing Small And Medium Enterprises In Tanzania, Peresi M. Bulemo

Tanzania Journal of Engineering and Technology (TJET)

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 …

Prospects Of Clean Cooking Energy In Africa - Transition Pathways And Implications, Joseph H. Kihedu Dr.

Tanzania Journal of Engineering and Technology (TJET)

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, …

Towards Metrology 4.0 In Developing Countries’ Manufacturing Industries, Jailos Nzumile

Tanzania Journal of Engineering and Technology (TJET)

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 …

Comprehensive Review Of Sensible Thermal Storage Systems For Cooking Applications, Anna K. Shariishoy

Tanzania Journal of Engineering and Technology (TJET)

This paper reviewed the sensible thermal storage systems specifically designed for cooking applications. The review focuses on the characteristics of storage materials, their practical applications, and the overall performance of the systems. The review consolidated an array of experimental and numerical research published across various sources such as journals, conferences, books, online resources, and professional reports. A systematic review is used to reach the conclusion of this paper. Significant findings from this study include the wide range of storage capacities attained from small-scale systems that can store ~1–5 MJ of energy for a single meal to bigger systems that can …