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 …

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 …

Disturbance-Learning Inertia Estimation Using Artificial Neural Networks For Power System Stability, Sospeter Igaanja Gabriel, Francis Mwasilu, Peter Makolo Dr.

Tanzania Journal of Engineering and Technology (TJET)

ABSTRACT

Power systems are progressively shifting towards low inertia as a result of incorporating significant amounts of intermittent and converter-based renewable energy sources, such as wind and solar power, into the current power grid network. This integration poses considerable problems to inertia and frequency control within the network due to a reduction in the proportion of synchronous generators. Furthermore, rapid frequency deviations occur due to the disparity between supply and demand during contingencies, complicating the maintenance of frequency stability within the power system. The disturbance-learning inertia estimation method for power system stability is presented. The simulation analysis is performed using …

Fast Sparse Image Reconstruction Models In Through-The-Wall Radars: A Review, Aude Kileo, Hashimu U. Iddi, Abdi Abdalla

Tanzania Journal of Science

Through-the-Wall Radar Imaging (TWRI) is a modern technology that uses electromagnetic waves to detect objects behind walls, with key applications in surveillance, rescue operations, and reconnaissance. Achieving high resolution in both down-range and cross-range requires ultra-wideband signals and long apertures, resulting in large data volumes, increased acquisition time, and high memory demands. TWRI employs Compressive Sensing (CS) to reduce computational time, which has proved its significance in many recent TWRI applications. However, in CS, image reconstruction approaches shift the computational burden from the sensing stage to the recovery stage, which prolongs the reconstruction times, making it unsuitable in time-sensitive applications. …

Hybrid Transformer-Bilstm Model For Early Fault Detection And Multiclass Classification Of Wind Turbine Faults Using Scada Data, Hassan Y. Mkindu

Tanzania Journal of Engineering and Technology (TJET)

Early and accurate fault detection in wind turbines is essential for improving operational reliability, reducing maintenance costs, and minimizing unplanned downtime. This study proposes a Hybrid Transformer-BiLSTM deep learning model for early fault detection and multiclass fault classification using Supervisory Control and Data Acquisition (SCADA) data. The proposed architecture combines the Transformer's self-attention mechanism to capture global temporal dependencies with the Bidirectional Long Short-Term Memory (BiLSTM) network's ability to model sequential fault evolution, enabling effective learning of multivariate time-series data. The model was developed and evaluated using the recently introduced CARE SCADA dataset, classifying five operating states: No Fault, Transformer …

A Quad-Port Dual-Band Elliptical Patch Mimo Antenna For 5g And Wlan Applications, Livingstone L. Kimaro, Hashimu Uledi Iddi, Mussa M. Kissaka, Neema S. Joseph

Tanzania Journal of Engineering and Technology (TJET)

A dual-band multiple-input multiple-output (MIMO) antenna for wireless local area network (WLAN) and fifth-generation new radio (5G NR) band n104 applications is presented. Two U-shaped slots interconnected back to back are etched on an elliptical shaped patch, four identical patch elements are then arranged orthogonally to form a quad-port antenna that resonates at 5.8 GHz and 6.7 GHz. Without additional extrinsic decoupling structures, the proposed design achieves measured isolation levels above 25.13 dB and 21.31dB, realized gains of 7 dBi and 7.2 dBi and -10 dB impedance bandwidths of 155.4 MHz and 90 MHz in the lower and upper frequency …

Design Of Permanent Magnet Synchronous Motor For Railways Traction Application, Anna S. Mwang'onda, Jackson J. Justo, Francis Mwasilu

Tanzania Journal of Engineering and Technology (TJET)

This paper presents the design of surface mounted permanent magnet synchronous motor (SMPMSM) intended for traction applications in standard gauge railway (SGR) for passengers. The proposed motor is rated 350 kW with a base speed of 3000 rpm. Moreover, speed control strategy with stability analysis is incorporated in the design to validate the performance of the SPMSM. The simulation results achieved a torque of approximately 1115 Nm at a terminal voltage of 800 V. The flux linkage of 150 mVs which ensures effective electromagnetic pertinence while maintaining safe magnetic loading because the flux density is less than 1.5 T. The …

Flexible Power Point Tracking For Active Frequency Regulation In Grid-Connected Photovoltaic Power Plants, Castor K. Haule, Sophia D. Kigodi, Emmanuel S. Matee, Francis Mwasilu

Tanzania Journal of Science

The increasing penetration of photovoltaic (PV) systems into modern power grids necessitates advanced control strategies capable of supporting grid stability. Traditional PV systems rely on Maximum Power Point Tracking (MPPT) to maximize energy extraction, limiting their ability to participate in grid-support functions such as frequency regulation or power curtailment. This paper presents a flexible power point tracking (FPPT) control strategy that enables PV systems to operate at arbitrary points along the power–voltage (P–V) curve. A multi-mode power management scheme is proposed, integrating conventional Perturb and Observe (P&O) MPPT with FPPT, allowing the system to switch dynamically between energy maximization and …

Mitigation Of Power Quality Problems In Songwe Power Distribution Line Using A Static Distribution Compensator, James Mhame, Emmanuel Matee, Francis Mwasilu, Sophia D. Kigodi

Tanzania Journal of Science

The Songwe electrical distribution system is prone to severe voltage drops that lead to frequent power outages in long feeders, light flickering, and the multi-operation of equipment and other appliances. The voltage at the switching station averaged 27.6 kV, 28.21 kV, and 25.79 kV in the years 2023, 2022, and 2021, respectively. Additionally, the maximum was 32.2 kV, below the nominal voltage, and the feeder has a very low power factor, which drops to 0.6 during peak hours. Currently, TANESCO uses automatic voltage regulators connected to a distant location from the switching station to two feeders with critical voltage drop …

Joint Channel And Phase Noise Estimation For Mmwave Ofdm Systems Using Adaptive Kalman Filtering, Kwame Salum Ibwe

Tanzania Journal of Science

This manuscript presents a joint channel and phase-noise estimation framework for millimeter-wave (mmWave) OFDM systems based on an adaptive extended Kalman filter (EKF). The proposed method formulates a unified state-space model that simultaneously tracks time-varying multipath channels and oscillator phase noise, a critical impairment in 5G NR frequency range 2 (FR2) and emerging 6G transceivers. An innovation-based covariance adaptation mechanism is introduced to enhance estimation accuracy while maintaining computational efficiency. Simulation results demonstrate that the proposed approach achieves up to a 5 dB SNR gain at a target BER of 10⁻³, maintains NMSE below 10⁻³ for linewidths up to 200 …

Hybrid Solar - Coal Thermal Energy System For Industrial Process Heat At Sayona Drinks Limited In Tanzania, Santos Kihwele, Elisha D. Bitesigirwe

Tanzania Journal of Engineering and Technology (TJET)

Over the past two decades, global efforts to mitigate pollution from conventional energy sources have intensified, with coal remaining a major contributor to carbon emissions. While fossil fuels cannot be eliminated from thermal generation in manufacturing industries, particularly in middle‑income countries such as Tanzania, they continue to dominate as the primary energy source. Industries including food and beverage, paper, textile, paints, chemicals, and pharmaceuticals require substantial thermal energy for heating and drying, and typically rely on coal and natural gas.This study introduces a unique application of a parabolic trough solar thermal system with integrated thermal energy storage, specifically tailored to …

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, …

Trajectory-Based Model Predictive Control For Rotary Crane Sway Suppression With Only Horizontal Boom Actuation, Haryson J. Nyobuya

Tanzania Journal of Engineering and Technology (TJET)

Safety is of biggest importance in construction and industrial activities involving rotary cranes. These cranes are huge and responsible of moving large parts or/and materials from different positions. Now operating these cranes tend to be subdue to pay load oscillations when moving the load for which is extremely dangerous when not suppressed. This study proposes the generation of trajectory using Model predictive control approach with reduced control horizon compared to state horizon. Reduced control horizon design reduces computational time for trajectory generation while maintaining the pay-load sways to a minimum. In this approach the complex dynamic model is reduced to …

On The Use Of Lorawan For Smart Fishing Applications In The Blue Economy Sector, Eva Shayo

Tanzania Journal of Engineering and Technology (TJET)

The growth of digital technology is expected to transform small-scale fishery sectors, where a need for robust, low-cost, long-range communication networks becomes critical. There exist several technologies that are used in the fishery sector but they are never affordable to small scale fisheries. This study evaluates the feasibility of using low cost Long Range Wide Area Network (LoRaWAN) technology specifically tailored for smart fishing environments to small scale fishery sector. Using simulation, we assess the performance of the key performance metrics including probability of success and energy efficiency under varying device densities and time. During evaluation, we considered end devices …

Optimal Design And Techno-Economic And Environmental Analysis Of A Hybrid Solar Pv-Battery-Generator System For Off-Grid Telecom Towers And Rural Households: Case Of Misughaa Village In Tanzania, Ibrahim Mwammenywa, Martha Mwaikenda

Tanzania Journal of Engineering and Technology (TJET)

Telecommunication services are pivotal for the socio-economic development of communities, regions, and countries. Extensive and reliable telecom infrastructure enables populations to leverage development opportunities and bridge the urban-rural divide. However, extending these services to rural areas often necessitates the deployment of telecommunication towers in locations lacking national grid access. Consequently, service providers typically rely on diesel generators (DG) for power, which introduces significant challenges. These challenges include a high operational expenditure (OPEX), rendering telecom services unaffordable for rural communities, and substantial environmental pollution from greenhouse gas (GHG) emissions. This study aims to present an optimal design, encompassing sizing and economic …

Voltage Profile Enhancement In Iliceto Shield Wire Scheme For Rural Electrification: Case Study Of Chalinze-Mbwewe Transmission Line In Tanzania, Ebeneza Chaula, Ibrahim Mwammenywa, Santos Kihwele

Tanzania Journal of Engineering and Technology (TJET)

Rural electrification faces challenges due to significant voltage drops over long transmission distances, affecting reliability and power quality. While the Iliceto Shield Wire Scheme (ISWS) offers a modern cost-effective solution, voltage stability remains a challenge. This study analyses voltage profile enhancement within ISWS, focusing on the Chalinze-Mbwewe section of the 132 kV transmission line, using LTSpice simulations. Due to LTSpice limitations, direct solar PV integration was mimicked by introducing a secondary voltage source at each load centre, producing 33 kV to match the original source voltage. This approach maintained improved voltage profile from Msoga Village to Mbwewe over 80.9 Kilometers. …

The Impact Of Gender Sensitization On Requirements Elicitation: A Controlled Experiment, Ruthbertha Kateule, Salome Maro, Leonard Peter Binamungu

Tanzania Journal of Engineering and Technology (TJET)

Previous studies in software engineering have reported the importance of considering gender aspects in various software engineering activities, including requirements engineering, however, to the best of our knowledge, no work has investigated the impact of gender sensitisation on eliciting gender inclusive software requirements. The objective of this study was to understand the impact of gender sensitisation on software requirements elicitation. We conducted a controlled experiment using 40 undergraduate students from three different computing programs at the University of Dar es Salaam. The 40 participants were divided into 9 groups with both males and females. The participants were asked to elicit …

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: …

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 …

Modelling And Analysis Of 50 Mwp Solar Pv Integration Into Tanzania’S Transmission Network: A Case Study Of Tagamenda Substation, Iringa Region, Santos Kihwele

Tanzania Journal of Science

While increasing the share of renewable energy in the grid, grid integration studies for the utility solar photovoltaic (PV) plants are vital, given their intermittency and the fact that Tanzania has never had one connected to the grid. This paper presents a 50 MWp grid integration study, including a technical analysis conducted using PSS®E software. The study investigates the grid behaviour during the integration of the 50 MWp solar plant, considering the most suitable technical and economic solutions. The study analysed the load flow under normal conditions, contingency analysis (N-1), short- circuit analysis, and voltage stability assessment. The results show …

Leveraging Convolutional Neural Networks For Through-The-Wall Radar Imaging: Challenges, Impacts, And Future Directions, Tumaini Edgar, Abdulla F. Ally, Abdi T. Abdalla

Tanzania Journal of Engineering and Technology (TJET)

Through-the-wall radar imaging (TWRI) is an essential technology for military and rescue applications; however, its performance in detecting and visualizing high-quality images of targets behind walls is significantly degraded by multipath reflections and signal attenuation. This paper reviews the current state of TWRI and its challenges, and explores the transformative potential of deep learning, particularly convolutional neural networks (CNNs), in addressing these challenges. Peer-reviewed articles published from 2018 to 2024 were analysed to examine CNN applications in addressing TWRI challenges. The analysis reveals that using CNNs, TWRI systems can be more effective by filtering wall distortions, reducing noise, lowering computational …

Design Of Virtual Impedance Controller For Parallel-Connected Converters In A Microgrid, Manyanda Makoye, Francis Mwasilu, Peter M. Makolo, Jackson Justo

Tanzania Journal of Science

This paper addresses the significant challenge of inaccurate power sharing among Distributed Generators (DGs) in islanded microgrids, which is primarily caused by mismatched feeder and line impedances. Conventional decentralized control solutions often fail to ensure accurate power sharing, especially when line impedances are resistive. To overcome this, the paper proposes a robust, coordinated Virtual Impedance Control (VIC) strategy for DGs. This method implements fixed virtual resistance and virtual inductance to standardize the output impedance characteristics of parallel-connected inverters, thereby minimizing impedance discrepancies and enhancing system stability through increased damping. The theoretical analysis and design of the VIC were validated through …

A Solar Pv System For Industrial Application- A Case Study Of A Cement Industry In Tanzania, Santos Kihwele

Tanzania Journal of Engineering and Technology (TJET)

This study presents an implementation of the largest behind-the-meter solar photovoltaic (PV) system for a cement industry in Tanzania. The project aims to supply energy for the industry’s own use, without any energy injection into the utility grid, for the purposes of cutting energy-related expenditure and reducing reliance on the utility grid. The project also aims to contribute to the efforts towards the application of renewable and alternative energy sources as a means to reducing carbon footprints, towards achieving the net-zero CO₂ emission goal. A comprehensive site assessment was conducted, analyzing factors such as location, land availability, climate data, …

Analysing The Impact Of Bi-Directional Application Of Iliceto Shield Wire Scheme For Rural Electrification In Tanzania: A Chalinze-Hale Transmission Line Case Study, Santos Kihwele, Prisca Paul

Tanzania Journal of Engineering and Technology (TJET)

Clean energy accessibility including electricity remains a major challenge in Tanzanian villages despite the many efforts made by its government.  The primary obstacle is that these villages are located more than 100 kilometres away from high-voltage to medium-voltage (HV/MV) transformer stations. Therefore, electrifying these villages by conventional method is financially not feasible. One of the low-cost rural electrification techniques that can be used to solve the issue is the "Iliceto Shield Wire Scheme" (ISWS) technology, In Tanzania, the application of ISWS technology seems to be very promising.  However, the technology can be integrated with locally available renewable energy sources ( …

Maximum Likelihood Symbol Timing Algorithm Based On Cyclic Prefix For Ofdm Systems, Kwame S. Ibwe

Tanzania Journal of Engineering and Technology (TJET)

In this paper, a blind symbol synchronization algorithm is presented for orthogonal frequency-division multiplexing (OFDM) systems, and a timing function based on the redundancy of the cyclic prefix (CP) is introduced. The existing algorithms rely on the prior knowledge of the channel energy distribution i.e. channel power profile. In practical environment the channel power profile is unknown to the receiver and its statistics are expected to be highly changing. Nevertheless, the use of pilot symbols in channel profile estimation reduces efficiency as data subcarriers are used to carry pilots instead of payload. In this paper a timing function that accounts …

Techno-Economic Analysis Of Hybrid Pv-Wind-Diesel Generator Swarm Grid For Rural Electrification In Tanzania, Ibrahim Mwammenywa

Tanzania Journal of Engineering and Technology (TJET)

Remote, rural, and off-grid communities, particularly in Sub-Saharan Africa (SSA), face significant challenges in securing reliable and affordable electricity. While solutions such as solar home systems (SHSs) and diesel generators (DGs) have been adopted by some individuals, their deployment is often not optimized to meet the full load demand. This study addresses this challenge by proposing a hybrid swarm grid (HSG) design that integrates photovoltaic (PV), wind energy, and diesel generators (DGs). Utilizing MATLAB/Simulink and HOMER, the HSG is modeled and optimized for a typical SSA village, incorporating real-world variables such as load demand profiles, solar irradiance, and wind patterns. …

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 …

Optimal Location And Sizing Of Facts Devices To Improve Voltage Profiles On A 132 Kv Mwanza-Musoma-Nyamongo Transmission Line, Peter Makolo

Tanzania Journal of Engineering and Technology (TJET)

Recently, utility companies have desired to supply quality, stable and reliable power to customers, and ensure they meet the demand. Flexible AC Transmission Systems (FACTS) dynamic compensator devices such as Static Synchronous Compensator (STATCOM), Static VAr Compensator (SVC) and Unified Power Flow Controller (UPFC) are an impeccable choice, however, cost is one of the limiting factors following these technologies. In addition, using FACTS devices in the system requires a detailed steady state, dynamic and optimisation analysis to effectively meet the purpose and ensure reduced cost. This paper proposes using an optimised FACTS device to improve voltage profile, power transfer, system …

Investigating The Harmonic Content Of A Pwm Inverter With Varying Modulation Index, Peter Makolo

Tanzania Journal of Engineering and Technology (TJET)

Photovoltaic energy is a clean and endless vital renewable energy. In order to generate electricity from solar energy an inverter is required to transform the direct current into alternating current. Also, with the emerging of new ultra-high voltage direct current transmission technology, the rectification and inverters play a great role. Most three-phase two-level inverters draw harmonics that cause heat dissipation, waveform distortions hence affect the electrical loads. Knowing that Total Harmonic Distortion content of voltage source inverter is important and must be within the allowable range. Several schemes are suggested to mitigate the distortion in order to produce as much …