Mechanical Engineering Commons^™

The Role Of Internal Factors On Vehicular Mobility, Aziz Mdimi

Tanzania Journal of Engineering and Technology (TJET)

Vehicle mobility internal factors are influenced by the performance state of the road surface quality, governor, engine, gear train, differential unit and mobility unit. Studies on vehicular mobility models exist for off-road external factors but absent on on-road internal factors. The on-road internal factors model describes the vehicular mobility performance as a function of internal factors. In the current undertaking, results are generated by the determination of mobility performance characteristics with the application of 2nd Order Ordinary Differential Equations and using Laplace operator with MATLAB Software simulation. The effect of road surface against the time taken varies accordingly. At a …

Energy Optimal Coverage Motion Trajectory Generation Using A Fourth-Order Motion Profile, Mathias Halinga

Tanzania Journal of Engineering and Technology (TJET)

Industrial machines are widely used in manufacturing sector to manufacture several products to meet customer demands. Most of these industries runs all the time throughout a day leading to high operating cost. To cut costs and satisfy customer demand for precise products, industrial machines’ motion generation is important in improving machine motion precision while using less energy. This study presents a coverage motion energy optimization which is generated by linear interpolation of each segment described by the fourth-order motion profile. The phase changes in the profile are attained with continuity of machine kinematic limits jerk, acceleration, and velocity, which are …

Mitigation Of Voltage Disturbances In Industrial Power Distribution Networks Using Dynamic Voltage Restorers, Aviti T. Mushi

Tanzania Journal of Engineering and Technology (TJET)

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 …

Thermal Energy Storage System Using Silica Sand As Heat Storage Medium: Simulation Of Geita Gold Mine, Santos Kihwele

Tanzania Journal of Engineering and Technology (TJET)

Currently, Geita Gold Mine (GGM) relies on electrical energy from the national grid and diesel power generators to generate electricity for various industrial applications. The plant currently spends a large amount of money on generating power from diesel generators. The total annual cost of power generation from diesel generators including lubricants is USD 56,057,990. The total annual fuel cost is USD 53,531,805 for a total of 54,985,473 liters per year. Most of the power generated by the generators is consumed in the industrial thermal processes. Thermal energy applications at the plant are thermal drying of the extracted ores to remove …

Wet Gas Metering Performance Using Conventional Flow Measurement Devices, Vitali Mwinyi

Tanzania Journal of Engineering and Technology (TJET)

The demand for and production of natural wet gas from wells has significantly risen in recent years. Although natural gas liquids hold substantial value in the oil and gas market, their presence in wet gas adversely affects gas metering, leading to overreading during measurement. A comprehensive study has been undertaken to formulate and enhance correlations for rectifying overreading in wet gas metering. Nevertheless, most current correlations are designed for horizontal configurations of traditional meters. Mitigating this constraint is crucial to consider the impact of gravity on pressure loss in vertically oriented systems. This study seeks to evaluate the efficacy of …

Fuzzy-Ahp Based Decision Support System For The Selection Of Optimal Maintenance Strategy For Meter Gauge Railway Infrastructure: A Review, Hamisi J. Maulid

Tanzania Journal of Engineering and Technology (TJET)

There are many uncertainties and complexities associated with maintaining Meter Gauge Railway (MGR) infrastructure, which calls for a methodical approach to decision-making. The development and application of a fuzzy-AHP-based decision support system (DSS) to select the optimal maintenance strategy for the MGR are presented in this study. The review covers research from 2013 to 2023 and focusses on the use of Multi-Criteria Decision Making (MCDM) and Fuzzy Analytic Hierarchy Process (Fuzzy-AHP) techniques in railway infrastructure maintenance. To manage the inherent uncertainties and subjective judgements involved in maintenance decision-making, the Fuzzy-AHP methodology combines fuzzy logic with the Analytic Hierarchy Process (AHP). …

The Impacts Of Renewable Energy Sources: A Review On Grid Inertia And Frequency Regulation, Sospeter Gabriel

Tanzania Journal of Engineering and Technology (TJET)

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 …

Analysis Of An Improved Reliability Dual-Buck Structured Three-Level Flying Capacitor Inverter, Almachius Kahwa Dr.

Tanzania Journal of Engineering and Technology (TJET)

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 …

Calibration Of Measurement Tools In The Experimental Test Rig For Hydropower Performance Evaluation, Ombeni J. Mdee

Tanzania Journal of Engineering and Technology (TJET)

The demonstration of a typical hydropower plant requires the development of a test rig with the installation of tools to measure the performance parameters. The measurement tools require a calibration process to improve the quality of recorded data. This study involved the calibration of traditional and automated measurement tools connected to the hydropower test rig through an Arduino microprocessor. The automated measurement tools included a pressure transducer, flow meter, digital tachometer, and torque transducer, while traditional measurement tools, including a pressure gauge, concrete water tank, contact tachometer, and force lever arm balance, were connected in the same test rig during …

Review On Gas-To-Liquids Conversion Technology: Lessons From Case Studies And Potential Strategies For Implementation In Tanzania, Joseph H. Kihedu

Tanzania Journal of Engineering and Technology (TJET)

This review paper explores the transformative potential of Gas-to- Liquids (GTL) technology for harnessing Tanzania's vast natural gas resources. With significant discoveries of natural gas reserves totalling up to 57 Tcf in fields such as Songosongo, Mnazi Bay, Block 1, 2, 3 and 4. Tanzania is positioned to leverage GTL technology to convert these resources into high-value liquid fuels like gasoline, diesel and naphtha. Review of GTL process, its products and applications has been done. By analysing successful GTL projects globally and drawing lessons applicable to Tanzania, this paper provides strategic recommendations for policymakers and stakeholders to foster GTL development. …

A Review Of Lithium-Ion Battery Capacity Fade Deceleration At Power Fluctuations In Renewable Energy Systems, Isaac Gwayi

Tanzania Journal of Engineering and Technology (TJET)

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 …

Assessment Of Maintenance Performance Level Of Selected Hydropower Plants In Tanzania, Mahamudu H. Mtebwa

Tanzania Journal of Engineering and Technology (TJET)

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 …

Design And Control Of A Versatile Modular Soft Robotic System With Integrated Resource Sharing And Self-Reconfiguration Capabilities, Joshua Knospler

Theses and Dissertations

Modular, self‑reconfigurable soft robots promise unprecedented versatility by combining the compliance of soft materials with the adaptability of modular architectures. This thesis presents an integrated system of pneumatic, bending-type soft actuator modules. Modules are compact and fully equipped with tunable magnetic and electromechanical connections for low‑power attachment and detachment and a novel power-air-communication (PAC) connector for seamless sharing of electricity, compressed air, and digital signals. This work examines two representative assemblies: ManusBot, a pinching gripper, and TendrilBot, a versatile linear configuration for various tasks. Their grasping performance, variable stiffness, and radial support capabilities are characterized. A magnetic interlock and an …

Predicting The Influence Of Aggregate Size And Distribution On Cementitious Concrete Properties: A Review, Innocent J. Macha

Tanzania Journal of Engineering and Technology (TJET)

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 …

Root Cause Analysis Of Performance Degradation For An Xyz Thermal Power Plant In Tanzania, Simon I. Marandu

Tanzania Journal of Engineering and Technology (TJET)

Thermal power plants in Tanzania have been experiencing performance degradation, typically arising from component and subsystem failures, which contribute to power system instability and unreliability. This paper presents a case study of the root causes of performance degradation of an XYZ thermal power plant. The study was conducted by reviewing plant documentations, including maintenance and operational data logbooks, and by standardising the approach through the adoption of ISO 14224:2016 for maintenance and reliability data exchange. Data evaluation was carried out using principal component analysis and scree plot analytical techniques to enhance the depth and accuracy of root cause identification. Additionally, …

Optimizing The Processing Temperature For Synthesis Of Silver Nanoparticles Within Cellulose-Wool Keratin Supramolecular Matrix Using Butylmethylimmidazolium Chloride Ionic Liquid, Ngesa E. Mushi

Tanzania Journal of Engineering and Technology (TJET)

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 …

Data-Driven Constrained Control, Ali Kashani

Mechanical Engineering ETDs

Ensuring safety is a fundamental challenge. Traditional methods often rely on precise mathematical models, which are difficult, impractical, or costly to obtain for real-world systems with complex, nonlinear dynamics. This dissertation develops direct data-driven control approaches that enable safe and efficient operation of nonlinear systems without requiring explicit models or performing system identification. This effort leverages machine learning, optimization, and control theory to bridge theoretical rigor and practical applicability. Deterministic guarantees are provided based on the Lipschitz continuity of the system, and probabilistic guarantees through scenario optimization. The computation of safe sets is performed using one-shot approaches with broad neural …

A Yolo-Based Deep Learning Approach For Vibration-Based Rotating Shaft Imbalance Detection, Abdelhameed Zayed Dr., Ali Siam Dr.

Journal of Engineering Research

One of the prevailing causes of vibrations in machines is rotor imbalance. Rotor balancing can be used to fix the majority of rotating machinery issues. When it comes to high-speed running equipment, even a slight imbalance can lead to serious issues and decrease the operational efficiency of rotating machinery. This work proposed a deep learning approach for the detection of binary and multiclass imbalance in rotating shafts. A YOLOv11 model-based approach is developed to detect imbalance and identify unbalanced rotor positions. To precisely identify unbalanced positions, this method trains the YOLOv11 model using numerous sets of measured response data and …

Investigation The Effect Of Integrating Solar Desalination Systems With Firefighting Networks For Coastal Cities, Ramy Elramy, Mohamed Mahgoub, Mohamed Abdelgaied, Ayman Refat Abd Elbar

Journal of Engineering Research

This study investigates integrating solar desalination systems with seawater-based firefighting networks as a sustainable solution for coastal cities facing freshwater scarcity. This study evaluates technical feasibility, economic impact, and operational performance by comparing conventional seawater firefighting infrastructure with systems utilizing desalinated water produced via solar energy. The methodology includes a detailed component and cost analysis of both systems, supported by experimental pump performance tests using varying salt concentrations and seawater. Results indicate that desalinated water systems offer significant economic savings—approximately 48.82%—due to reduced corrosion, lower maintenance demands, and improved pump efficiency. Experimental findings also show that increased salinity accelerates cavitation …

Cyclic Combustion Pressure Dynamics Of A Diesel Engine Operating On Waste Frying Oil Biodiesel Blends Using Wavelets, Shady Elmozy, Ahmed Khaira Dr., Elshenawy Elshenawy Prof. Dr., Ali Mohamed Dr., Medhat Elkelawy Prof. Dr,

Journal of Engineering Research

This paper investigates the cyclic combustion pressure dynamics of a single-cylinder diesel engine burning waste frying oil biodiesel blends, employing statistical analysis and continuous wavelet transform (CWT) to evaluate combustion stability. Experiments were conducted at a constant engine load (90%) and speed (1500 rpm), with in-cylinder pressure data collected over 400 consecutive cycles for conventional diesel (RD) and biodiesel blends (UB10, UB30, UB50). Results demonstrate that biodiesel blends marginally reduce average peak cylinder pressure (PP) by 0.3–3.8% while lowering PP variability, evidenced by declining coefficients of variation (COV-PP: 1.27–1.48%), attributed to biodiesel’s elevated viscosity promoting consistent fuel-air mixing. Conversely, mean …

Combustion Characteristics And Cycle-To-Cycle Variations In A Diesel Generator Fueled With Used Frying Oil Biodiesel Blends, Shady Elmozy, Ahmad Khira Dr., E. A. El Shenawy Prof. Dr., Medhat Elkelawy Prof. Dr, Eng.

Journal of Engineering Research

This paper investigates the combustion characteristics and cycle-to-cycle variations in a stationary direct-injection diesel generator fueled with biodiesel derived from used frying oil (UFO) blended with conventional diesel. Used frying oil methyl ester (UFOME), referred to as UB100, was produced through a single-step alkali transesterification process and blended with diesel fuel in varying proportions (UB10, UB20, UB30, UB40, and UB50). Experiments were conducted on a single-cylinder, naturally aspirated diesel engine operating at a constant speed of 1500 rpm under five different load conditions: 0%, 25%, 50%, 75%, and 90%. In-cylinder pressure data from 400 consecutive cycles were analyzed to determine …

An Engineering Solution For Fan Aeroacoustics Measurements Correction In A Non-Anechoic Testing Environment, Saad-Eldin Taha, Mohamed Y.Zakaria, Mohamed Abdelgaied, M.M. Bassuoni Prof. Dr.

Journal of Engineering Research

Abstract- Nowadays, acoustic signatures of daily used applications are to be minimized. The study of noise generated through aerodynamic interaction with moving bodies has passed through different phases since the early 50s, and this leads to the evolvement of many analytical, empirical and computational techniques in order to be able to estimate the emitted noise. Concerning fan blades, until now the researches are still going for a reliable method for noise estimation during the early phases of design which help in the development of blades with a lower aeroacoustic signature, the Brooks, Pope and Marcolini (BPM) model was chosen to …

An Eulerian-Pfem Approach To Model Transient Capillary Forces On Moving Contact Lines Of Spreading Liquid Drops: Applications In Hydraulic And Fluid Dynamics, Elaf N. Mahrous, Syed Yousufuddin, Muhammad Saleem Professor, Mohammed N. Iqbal, Muhammad T. Bin-Saleem

Journal of Engineering Research

This study addresses the complexities of simulating multiphase flows, particularly the dynamics of droplet behaviour on solid substrates, which are influenced by intricate capillary interactions. Despite advancements in fixed-grid and moving-grid methodologies, there remains a critical gap in accurately modelling transient phenomena and dissipative forces at the solid-liquid interface. We introduce a novel Eulerian-particle finite element method (PFEM) framework that captures the transient capillary forces associated with the movement of contact lines in liquid droplet spreading scenarios. Through a numerical assessment of three established dissipative force models—Jiang’s, Bracke’s, and Seeberg’s we identify Jiang's model as the most effective and stable …

Anhydrous Ammonia As A Hydrogen Carrier Fuel For Solid Oxide Fuel Cells, Cole Anthony Wilhelm

Dissertations - ALL

In the years since humans realized that our actions could have profoundly harsh effects on the environment, we have been searching for ways to minimize our impacts, while also maintaining the same standard of living. One of the actions with such effects is power generation using fossil fuels, which has long been the largest source of energy. While efforts should be made to improve the efficiency of these power generation plants, we should also work to identify alternative opportunities for power generation without the use of fossil fuels. Some of these opportunities include hydroelectric, photovoltaic, wind, nuclear, and the combustion …

Corrosion Mitigation And Monitoring Of Bridge Tendons And Failure Forecasting Of Wastewater Force Mains, Stanley Chike Agbakansi

USF Tampa Graduate Theses and Dissertations

Corrosion remains a significant threat to civil infrastructure, resulting in costly repairsand potential structural failures. This dissertation addresses three critical aspects of corrosion: mitigation and monitoring of post-tensioned bridge tendons, and failure forecasting of wastewater force mains due to internal corrosion.

First, the research investigates the effectiveness of corrosion inhibitors (CIs) applied via pressure injection (impregnation) in post-tensioned tendons. The protective mechanisms and long-term performance of various inhibitors were evaluated to identify the most effective formulations. Among the tested inhibitors, MCI-2020 — a water-based, migratory, mixed-type corrosion inhibitor — demonstrated the most promising results, showing excellent corrosion protection while preserving …

Tailoring Gel Polymer Electrolytes For Advancing Quasi-Solid-State Batteries, Linrui Duan, Juchen Zhang, Mataz Alcoutlabi, Hongtao Sun

Mechanical Engineering Faculty Publications

Gel polymer electrolytes (GPEs) have attracted considerable attention due to their advantageous properties, such as uniform lithium deposition, stable solid electrolyte interphase (SEI) formation, nontoxicity, nonflammability, and leak-proof characteristics. In this study, a polyvinylidene fluoride hexafluoropropylene copolymer (PVDF-HFP)-based gel polymer electrolyte is synthesized via photo-polymerization, with a focus on examining the effects of curing time on electrolyte performance. The findings reveal that UV irradiation conditions significantly influence key material and electrochemical properties of the GPEs, including lithium-ion transference number, ionic conductivity, crystallinity, morphology, and liquid electrolyte uptake. Notably, the GPE cured for 120 s exhibited optimized performance, achieving an ionic …

Empowering Engineering Students To Become More Effective And Self-Regulated Learners Through Course-Integrated Learning Strategies Intervention: A Pilot Study In A Solid Mechanics Course, Huihui Qi, Richard Eugene Vallejo Jr., Changkai Chen, Minju Kim, Alex M. Phan, Marko Lubarda, Celeste Pilegard, Curt Schurgers

Psychology Faculty Articles and Research

Learning is a lifelong process exercised within and beyond the classroom and a vital skill in almost all technical professions. Engineers, in particular, are impacted by rapidly evolving technologies and practices that require continuous learning and adaptation long after their training and the initial transition into their professional careers. However, despite the critical role of learning in their academic success and profession, engineering students experience academically rigorous and challenging courses with very little emphasis or conscious focus on learning strategies that power effective learning. Often-used learning strategies such as rereading, highlighting, repetition, and memorization are intuitive for many students, yet …

Cellular Automaton Simulation Of Grain And Sub-Grain Evolution With Eutectic Growth In Laser Scanned And Rescanned Al–10si, With Experimental Validation, Kai Kang, Lang Yuan, Can Sun, Javier Miranda, André B. Phillion

Faculty Publications

This study presents a three-dimensional Cellular Automaton (3D CA) model incorporating eutectic growth mechanisms to simulate grain and sub-grain structure evolution in an additive manufacturing (AM) scenario, with surface laser rescanning of Al–10Si alloy as a case study. Unlike conventional CA models in AM, this work introduces a eutectic solidification framework within the CA approach, allowing dynamical transitions between dendritic and eutectic growth modes based on local thermal and solute conditions. The CA model integrates finite element analysis (FEA)-derived thermal data, solute redistribution tracking, nucleation behaviors, and growth kinetics under rapid solidification conditions in laser scanning and rescanning. The simulation …

Cellular Automaton Simulation Of Grain And Sub-Grain Evolution With Eutectic Growth In Laser Scanned And Rescanned A1-10si, With Experimental Validation, Kai Kang, Lang Yuan, Can Sun, Javier Miranda, André B. Phillion

Faculty Publications

This study presents a three-dimensional Cellular Automaton (3D CA) model incorporating eutectic growth mechanisms to simulate grain and sub-grain structure evolution in an additive manufacturing (AM) scenario, with surface laser rescanning of Al–10Si alloy as a case study. Unlike conventional CA models in AM, this work introduces a eutectic solidification framework within the CA approach, allowing dynamical transitions between dendritic and eutectic growth modes based on local thermal and solute conditions. The CA model integrates finite element analysis (FEA)-derived thermal data, solute redistribution tracking, nucleation behaviors, and growth kinetics under rapid solidification conditions in laser scanning and rescanning. The simulation …

Towards Sustainable Manufacturing: A Framework For Resource Conservation And Waste Mitigation, Mahmood Talal Sultan

Thesis/ Dissertation Defenses

The manufacturing industry drives economic expansion, but it also contributes significantly to environmental change and shortages of resources. Therefore, the transformation to sustainable manufacturing has become an urgent need, driven by worldwide efforts to address climate change, minimize waste, and protect valuable assets. This thesis develops a robust framework tailored to the manufacturing sector, focusing on resource conservation and waste reduction. The framework is built on the identification and categorization of Key Performance Indicators (KPIs) and assessment tools, which address five major implementation challenges: complex supply chains, regulatory barriers, economic challenges, technological limitations, and social and cultural challenges.

To build …