Investigating The Harmonic Content Of A Pwm Inverter With Varying Modulation Index,
2025
Department of Electrical Engineering, University of Dar es Salaam, P.O. Box 35131, TANZANIA
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 …
A Polar Turbulence Invariant Map With Applicability To Realisable Machine Learning Turbulence Models,
2025
Wright State University - Main Campus
A Polar Turbulence Invariant Map With Applicability To Realisable Machine Learning Turbulence Models, James G. Wnek, Christopher Schrock, Eric M. Wolf, Mitch Wolff
Mechanical and Materials Engineering Faculty Publications
Invariant maps are a useful tool for turbulence modelling, and the rapid growth of machine learning-based turbulence modelling research has led to renewed interest in them. They allow different turbulent states to be visualised in an interpretable manner and provide a mathematical framework to analyse or enforce realisability. Current invariant maps, however, are limited in machine learning models by the need for costly coordinate transformations and eigendecomposition at each point in the flow field. This paper introduces a new polar invariant map based on an angle that parametrises the relationship of the principal anisotropic stresses, and a scalar that describes …
Implementation Of Reliability Centered Maintenance On Crude Booster Pump,
2025
Department of Metallurgical and Materials Engineering, Faculty of Engineering, Universitas Indonesia, Depok, West Java, 16424, Indonesia
Implementation Of Reliability Centered Maintenance On Crude Booster Pump, Dzulfikar Ali Hafizh, Maya Agustianingrum Putri St., Ph.D., D. Rizal, Adzra Qanita
Journal of Materials Exploration and Findings
Crude oil booster pump is one of the critical equipment in oil refinery operations. In aging plants that have been operating for more than 25 years, where reliability and maintenance issues on equipment often cause operational disruptions and even unplanned shutdowns. This study aims to develop a structured reliability-centered maintenance (RCM) strategy for crsude oil booster pump systems that is also in line with the principles of asset integrity management system (AIMS). This methodology follows the RCM II approach, starting with system function analysis, failure mode identification, and criticality assessment through Failure Mode, Effect, and Criticality Analysis (FMECA) to determine …
Investing Hysteresis In Floodplain Dynamics Of Lakes In The Middle St. Johns River Using Sentinel-1 Sar Imagery,
2025
Embry-Riddle Aeronautical University
Investing Hysteresis In Floodplain Dynamics Of Lakes In The Middle St. Johns River Using Sentinel-1 Sar Imagery, Keenan Hubbard
Doctoral Dissertations and Master's Theses
Floodplain dynamics are often complex, with hysteresis potentially affecting the temporal relationship between flood stage and flood extent during subsequent inundation phases. This study leverages Sentinel-1 synthetic aperture radar (SAR) imagery to map flood extent in the Middle St. Johns River Lake floodplains and examine the presence of hysteresis during flood events. SAR scenes corresponding to river gauge readings were analyzed from the rising and falling limbs of a flood hydrograph. By comparing these flood maps, we assess differences in inundated areas at equivalent water levels during each stage of the flood event. The findings aim to enhance flood monitoring …
Modeling Of Carbonization And Absorption Processes In Soda Ash Production,
2025
Tashkent state technical university. Adress: Uzbekistan, Tashkent city, University street 2. E-mail: [email protected];
Modeling Of Carbonization And Absorption Processes In Soda Ash Production, Nadirbek Rustambekovich Yusupbekov, Djalolitdin Paxritdinovich Mukhitdinov, Fatima Faxritdinovna Iskhakova
Chemical Technology, Control and Management
The article considers the problem of modeling the ammonia-soda process of soda ash production and presents the chemistry of sodium bicarbonate (NaHCO₃) formation. The equation of the kinetics of the reaction, used as a model of the carbonation process, is derived from a system of equations and its computer model is compiled. The system of differential equations reflecting the kinetics of the process was solved in the Mathcad package. The result of the modeling is presented. Based on the experimental data, the dependence of the absorption column performance on temperature and the dependence reflecting the optimal value of the absorption …
Algorithms For Making Control Systems Based On Neural Network Technology To Automate Dynamic Plants,
2025
Tashkent state technical university. Adress: Uzbekistan, Tashkent city, University street 2. E-mail: [email protected],
Algorithms For Making Control Systems Based On Neural Network Technology To Automate Dynamic Plants, Jasur Sevinov, Abdishukurov Maqsudovich Shavkat
Chemical Technology, Control and Management
This paper examines the stages of multilayer neural network technology for the control and identification of dynamic systems. It is seen many ways to use multilayer neural networks in control systems. Neural controllers are based on several models and algorithms. Examples of such algorithms include the predictive model-based control algorithm, the Narma-L2 control algorithm, and the benchmark model-based control algorithm. These controllers illustrate various general ways to use multilayer neural networks in control systems. Common, standard linear control architectures have been proposed for many neural controllers.
Data-Driven Constrained Control,
2025
University of New Mexico
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 …
Towards Metrology 4.0 In Developing Countries’ Manufacturing Industries,
2025
Department of Legal and Industrial Metrology, College of Business Education, P.O Box 1968 Dar es Salaam, Tanzania
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 …
Potential Use Of Pump As Turbine Coupled To Self-Excited Induction Generator For Micro-Hydro Cooking And Cooling Applications,
2025
Mechanical & Industrial Engineering Department, University of Dar es Salaam, TANZANIA
Potential Use Of Pump As Turbine Coupled To Self-Excited Induction Generator For Micro-Hydro Cooking And Cooling Applications, Emanuel J. Nyirenda
Tanzania Journal of Engineering and Technology (TJET)
Clean cooking and efficient cooling in developing countries have recently become areas of great focus. Further, the environmental impact of flooding in high-capacity hydroelectric plants has become a major concern. As a result, there is growing emphasis on developing sustainable and decentralized energy solutions, focusing on the potential of micro-hydro systems, especially in rural and remote areas. Although there are several alternative energy generation methods, their application is not straightforward. One of the latest technologies under research is using pumps as turbines coupled to an induction generator. This paper explores through a rigorous experimental approach the possibility of using a …
Calibration Of Measurement Tools In The Experimental Test Rig For Hydropower Performance Evaluation,
2025
Department of Energy and Petroleum Engineering, University of Dodoma, P. O. Box 259, Dodoma, Tanzania.
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 …
Energy Optimal Coverage Motion Trajectory Generation Using A Fourth-Order Motion Profile,
2025
Department of Mechanical and Industrial Engineering, University of Dar es Salaam, P.O Box 35131, Dar es Salaam, Tanzania
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 …
Design And Optimization Of Aquaculture Gear: Development Of A Cage-Integrated Reeling Mechanism For Oyster Farming,
2025
University of South Alabama
Design And Optimization Of Aquaculture Gear: Development Of A Cage-Integrated Reeling Mechanism For Oyster Farming, Felicity Bryant
Honors Theses
This project encompasses the design, fabrication, and testing of a cage-integrated reeling system aimed at reducing the physical labor required in oyster aquaculture at Bama Bay Oyster Farm, the last operational oyster farm in Mobile Bay. The proposed system includes two primary components: lightweight, modular oyster cages and a dual-winch reeling device for automated retrieval. Three cage prototypes—rectangular, oval, and hexagonal—were evaluated for structural performance and fabrication feasibility. The oval design was ultimately excluded due to practical fabrication limitations. The rectangular and hexagonal designs were fabricated using recycled materials and tested under the most extreme environmental conditions derived from years …
Application Of Artificial Neural Network Models For Predicting Diesel And Petrol Prices In The Geographically Sparsed Regions In Tanzania,
2025
University of Dar es Salaam
Application Of Artificial Neural Network Models For Predicting Diesel And Petrol Prices In The Geographically Sparsed Regions In Tanzania, John M. Kafuku
Tanzania Journal of Engineering and Technology (TJET)
Fuel consumption in Tanzania, mainly diesel and petrol, accounts for 82 percent of the energy consumption in the country, with significant price volatility affecting market stability, availability of fuel, and investment decisions. This study uses an artificial neural network (ANN) with a backpropagating algorithm to predict fuel prices in four regions of Tanzania. Key input parameters include the currency inflation rate (CIR), the petrol fuel inventory (PFI), the diesel fuel inventory (DFI), and the fuel transport costs (FTC). The study selected the 6-10-10-2 ANN structures for Sumbawanga-Rukwa, Mpanda-Katavi, and Mbeya-Mbeya as well as 6-10-9-2 for the Songea-Ruvuma region. The results …
Microwave Ore Pre-Treatment Review And Process Flowsheet Conceptualization,
2025
Department of Mining and Mineral Processing Engineering, School of Mines and Geosciences, University of Dar es Salaam, P. O. Box 35131, Dar es Salaam, Tanzania
Microwave Ore Pre-Treatment Review And Process Flowsheet Conceptualization, Baker F. Giyani
Tanzania Journal of Engineering and Technology (TJET)
The global demand for mineral commodities has increased dramatically over the years, and this is largely due to several factors, including technological advancements, industrialization, and a rise in population. Further, the demand keeps increasing because the ore being mined is becoming more complex, and the feed grade is declining over the years, prompting the need for innovative technologies to treat such ores more efficiently. Microwave ore pre-treatment is one of the potential technologies that can be employed to improve process performance. This is possible because ores are composed of both good-microwave heaters and poor microwave heaters, which creates thermal stresses …
Clustering Mini-Grids To Enhance Power Systems Reliability In Distributed Generation,
2025
Department of Electrical Engineering, College of Engineering and Technology, University of Dar es Salaam, P.O. Box 35131, Dar es Salaam, Tanzania
Clustering Mini-Grids To Enhance Power Systems Reliability In Distributed Generation, Santos Kihwele
Tanzania Journal of Engineering and Technology (TJET)
This study investigates the effectiveness of clustering mini-grids as a method to improve the reliability and operational stability of distributed generation systems in remote areas, particularly where renewable energy sources are predominant. As renewable resources like solar and wind are increasingly integrated into mini-grids, these systems face various challenges, particularly in maintaining stable voltage and frequency across interconnected networks. Such issues are compounded by the intermittent nature of renewable energy sources and the lack of extensive communication infrastructure in rural or resource-constrained settings. To address these control challenges, this study applies droop control techniques to two mini-grids in Uganda, utilizing …
On The Exploration Of Crystallographic Anisotropy And Defects In Shock Loading Using Molecular Dynamics,
2025
Air Force Institute of Technology
On The Exploration Of Crystallographic Anisotropy And Defects In Shock Loading Using Molecular Dynamics, Benjamin P. Helman
Theses and Dissertations
The impact of crystallographic orientation, grain boundaries, and vacancies on the shock behavior of aluminum was investigated using molecular dynamics simulations. Shock loading in the [001], [011], and [111] directions was explored, revealing anisotropic behavior in shock speed, melting, dislocation density, and unique phase changes. The Hugoniot elastic limit in the [100], [110], and [111] directions was calculated as 23.2 GPa, 24 GPa, and 18.4 GPa respectively. These results were found to be an order of magnitude larger than the compressive yield strength computed at equilibrium. Additionally, metastable melting in the [011] and [111] directions occurred roughly 1000 K below …
Assessment Of Wind Speed Characteristics And Available Wind Power Potential For Electricity Generation In Tanzania,
2025
Department of Physics, University of Dar es Salaam, P.O Box 35063, Dar es Salaam, Tanzania
Assessment Of Wind Speed Characteristics And Available Wind Power Potential For Electricity Generation In Tanzania, Mwingereza John Kumwenda
Tanzania Journal of Engineering and Technology (TJET)
The energy demand and its associated crises are attracting significant attention due to population increase and economic growth especially in developing countries. Fossil fuel-based energy source stand as a prominent anthropogenic resource but they are accompanied with increased carbon emissions and heightened environmental concerns. Renewable energy sources such as wind energy can offers a lot of potential for sustainable growth in the energy sector of developing nations like Tanzania. Thus, this work investigated wind speed characteristics and available wind power potential in six selected regions in Tanzania with different topographical features for future electricity generation. The data of the wind …
Heavy Metals Pollution In Roadside Ecosystems,
2025
Department of Chemical and Process Engineering, College of Engineering and Technology, University of Dar es Salaam Tanzania
Heavy Metals Pollution In Roadside Ecosystems, Lilian Matafu
Tanzania Journal of Engineering and Technology (TJET)
Heavy metals refer to metallic elements that are characterized by having a relatively high density and they are toxic or poisonous even at low concentration. They are environmental pollutant owing to toxicity and longevity in atmosphere and ability to accumulate in living things via bioaccumulation. They tend to enter in different system such as food chain. Analyses of water, soil sediment and the surrounding growing plants (Cynodon dactylon and Cyperus species) for selected heavy metals (Cd, Pb, Zn and Cu) were conducted on a roadside pond located at Boko MSB, Dar es Salaam. Pond water, soil sediments and plant samples …
Safety And Optimality Monitors For Learning-Enabled Systems Using Conformal Prediction,
2024
Washington University in St. Louis
Safety And Optimality Monitors For Learning-Enabled Systems Using Conformal Prediction, Jackson Cox
McKelvey School of Engineering Graduate Student Theses & Dissertations
The use of machine learning to create data-driven plant models and controllers has led to an increased need for safety and optimality monitors for model-based systems. System plant models are subject to uncertainty due to learning constraints such as unseen data and overfitting or physical constraints such as unknown dynamics and noise. This uncertainty is detrimental to safety-critical systems and must be properly regulated. To curb this uncertainty, we create prediction sets using the guarantees provided by Conformal Prediction. With a user-specified high probability, these prediction sets contain the true plant system states for an entire prediction horizon, which we …
Cal Poly
3d Printed Microfluidic Fabrication Methodology, Characterization, Mechanical Design, And Applications In Electrostatic Artificial Muscles And Benthic Microbial Fuel Cells, Terak B. Hornik
Master's Theses
The fabrication of microfluidic devices often requires specialized methods. The development of these methods requires careful characterization and understanding of the processes involved. Using primarily PolyJet 3D printing technology, microfluidics offers a wide scope of applications such as microfluidic benthic microbial fuel cells (MBMFCs) and electrostatic artificial muscles. MBMFCs benefit from the confinement of the microbes resulting in close proximity between the electrode and the organisms. Using a modular design called the Sponge, assembly and upscaling is possible. Electrostatic artificial muscles benefit from a microfluidic approach due to the non-linearity of electrostatic attraction creating disproportionate benefits when miniaturized. When designed …
