Engineering Commons^™

Key-Based Authentication Scheme For Evtol Drones Using Chebyshev Chaotic Maps, Eduardo A. Hernandez Escobar

Master's Theses

The development of electric Vertical Take-Off and Landing (eVTOL) drones signifies a substantial advancement in urban air mobility, ready to transform transportation models in densely populated regions. These advanced drones, distinguished by their capacity to function in limited spaces and their minimized environmental impact, are set to transform individual, shipping, emergency services, and public safety activities. Nonetheless, like any transformational technology, the implementation of eVTOL systems presents many challenges, especially in the realm of cybersecurity. Adding many devices and entities to an eVTOL network increases the risk of privacy and security attacks. This paper proposes a key-based authentication scheme that …

Sensors And Sensibilities: Exploring Interactions For Habitat Comfort With An Environmental-Physiological Sensing Eyewear In The Wild, Sailin Zhong, Patrick Chwalek, Nathan Perry, David Ramsay, Clayton Miller, Denis Lalanne, S. Hamed Alavi, A. Joseph Paradiso

Research Collection College of Integrative Studies

Buildings increasingly incorporate sensing and actuation techniques to automate the regulation of temperature, lighting, ventilation, and more. This trend seeks to minimize human intervention, justified by the promise of enhancing energy optimization. However, it has been widely acknowledged that loss of control over environmental conditions can lead to a diminished perception of comfort and compromised long-term user awareness and satisfaction. How can we envision building systems that can interact with building inhabitants and engage them at the “right” time and place? In this work, we address this challenge through three key contributions: 1) AirSpecs, a novel smart glasses-based system that …

Hierarchical Frameworks For Scaling-Up Multi-Agent Coordination, Minghong Geng

Research Collection School Of Computing and Information Systems

Multi-agent reinforcement learning has emerged as a powerful framework for developing collaborative behaviors in autonomous systems. However, existing MARL methods often struggle with scalability in terms of both the number of agents and decision-making horizons. My research focuses on developing hierarchicalapproaches to scale up MARL systems through two complementary directions: structural scaling by increasing the number of coordinated agents and temporal scaling by extending planning horizons. My initial work introduced HiSOMA, a hierarchical framework integrating self-organizing neural networks with MARL forlong-horizon planning, and MOSMAC, a benchmark for evaluating MARL methods on multi-objective MARL scenarios. Building on these foundations, my recent …

Development Of Fuzzy Ontology For Explainable Artificial Intelligence For Decision-Making In Fuzzy Environment, Pavel Kosov

Chemical Technology, Control and Management

In modern artificial intelligence systems, there is an acute need to understand the decision-making logic of "black box" algorithms. Our research proposes an innovative method for increasing the transparency of such systems through the formalization of fuzzy explanatory mechanisms. We have developed an extension of existing ontological approaches by introducing the concept of fuzziness into the structure of explanatory properties, which allows overcoming the fundamental limitations of traditional XAI methods. The proposed formalization is based on the theory of collective mental models and principles of fuzzy logic, providing a more accurate reflection of uncertainty and subjectivity in expert knowledge. Our …

Improving Image Quality In Electrical Capacitance Tomography Using Otsu Thresholding, Josiah Nombo

Tanzania Journal of Engineering and Technology (TJET)

Electrical Capacitance Tomography (ECT) is an imaging technique used in industrial process monitoring, particularly for monitoring and measuring the composition of multiphase flows. Despite its widespread application, the commonly used Linear Back Projection (LBP) algorithm often produces low-quality images due to its limited ability to handle high permittivity contrasts and nonlinearities. This study investigates the use of Otsu thresholding as a post-processing technique to enhance ECT image quality. By maximizing inter-class variance in the image histogram, Otsu thresholding improves contrast, clarity, and structural definition, enabling more effective segmentation of oil and gas components in multiphase flows. The proposed Otsu-based reconstruction …

Artificial Intelligence Applications For Grid-Connected Solar Inverters, Utkirjon Ubaydullaev, Sarvinoz Mirzaeva, Hasan Mustafoev

Chemical Technology, Control and Management

The increasing global demand for renewable energy has highlighted the importance of grid-connected solar inverters in ensuring efficient and stable power conversion. However, challenges such as fluctuations in solar energy generation, grid disturbances, and power quality issues necessitate advanced control strategies. The integration of artificial intelligence (AI) into solar inverters presents a transformative solution, enhancing performance, adaptability, and reliability in real-world applications.

This review explores the role of AI techniques, including machine learning (ML), deep learning (DL), fuzzy logic, and reinforcement learning (RL), in optimizing key inverter functionalities such as maximum power point tracking (MPPT), fault detection, power quality enhancement, …

A Critical Realist Erp Implementation In Zimbabwean Mining Industry Organisations, Jairos Mukwenha

Tanzania Journal of Engineering and Technology (TJET)

This research uses a critical realist framework to examine the factors influencing the success of enterprise resource planning (ERP) system implementation in Zimbabwean mining industry organisations. From the perspective of critical realism, the mining industry in Zimbabwe faces a complex interplay of opportunities and obstacles while implementing ERP systems. The deployment of ERP in mining firms is critically examined in this paper, emphasising how these systems might improve operational efficiency while considering Zimbabwe's particular socioeconomic circumstances. By exploring underlying structures, mechanisms, and outcomes, the research aims to identify critical challenges and opportunities and develop practical recommendations for improving ERP adoption …

Development Of A Microcontroller-Based Intelligent Traffic Light Control System For Vehicular Movement In T-Junctions, Frederick O. Ehiagwina

Tanzania Journal of Engineering and Technology (TJET)

This research is devoted to the issue of regulating traffic congestion in major cities using light-dependent resistors coupled with the PIC16F877A microcontroller. This study proposes an intelligent traffic control system for T-Junctions, utilizing sensing and control to optimize traffic flow through dynamic phase adjustments and congestion reduction, enabled by a microcontroller-based decision-making system. The proposed system reduces traffic congestion, automates control, and enhances safety, minimizing accidents and lowering infrastructure costs. Under simulated environment, it demonstrates an average response time of 50 ms and achieves 99% accuracy in displaying the correct countdown. Finally, the number of state transitions handled per minute …

Developing Predictive Mathematical Model For Optimizing Coating Weight Variation In Galvalume Production: A Case Study Of A Metal Industry, Victoria Mahabi

Tanzania Journal of Engineering and Technology (TJET)

Variations in coating weight for galvanized steel sheets can result in notable differences between batches. Such variations may cause various issues, such as diminished corrosion resistance, lower mechanical strength, and visual defects, which can ultimately drive-up costs, lead to customer dissatisfaction, and pose safety risks. Even with attempts to manage elements like air knife pressure and line speed, coating weight inconsistencies remain challenging. The research focuses on developing a predictive mathematical model designed to optimize variations in coating weight during Galvalume production. The critical parameters influencing coating weight variation were identified and analysed using a systematic literature review, primary data …

Design And Performance Analysis Of Fiber Bragg Grating Temperature Sensor For Industrial Processes Sensing Applications, Paul Stone Stone Brown Macheso S.B.

Tanzania Journal of Engineering and Technology (TJET)

The Fiber Bragg Grating (FBG) sensor has become a widespread sensing device because of its small size, passive design, immunity to electromagnetic interference, and direct ability to measure physical properties like temperature and strain. Recently, femtosecond infrared laser processing and regeneration techniques have resulted in the development of stable high-temperature gratings, which are a powerful tool in smart factories, an aspect of the fourth Industrial Revolution (4IR), and show promise for application in harsh environments like high pressure, high temperature, or ionizing radiation. The development of stable high-temperature gratings that can withstand harsh environmental factors like high temperatures, pressures, and …

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 …

A Fuzzy Based Framework For Sustainable Technology Selection In Small-Scale Gold Mining Operations, John M. Kafuku

Tanzania Journal of Engineering and Technology (TJET)

Small-scale gold mining (SSGM) operations in Tanzania has been operating inefficiently due to inadequate mining processing technologies, poor working tools, lack of enough capital, and insufficient electricity. Despite the efforts made by different stakeholders in boosting the sustainability of SSGM yet the sector has not reached the expected goal. This paper proposes a framework for appropriate technology selection to help small scale gold miners in evaluating various gold mineral processing technologies. The framework utilizes the fuzzy logic set theory for technology evaluation and selection. The developed framework for technology selection upon validation provided results that technology adequacy of more than …

Synthetic Inertia Provision For Load Frequency Control In Networks With High Penetration Of Renewable Energy Sources, Paulina Mkoi

Tanzania Journal of Engineering and Technology (TJET)

The integration of renewable energy sources (RESs) such as solar photovoltaic (PV) and wind energy has become a promising solution as the world shifts toward clean energy. Solar PV and wind resources are increasingly replacing conventional synchronous generators, leading to reduced system inertia and increased vulnerability to frequency instability during disturbances. To address this challenge, this study proposes a novel synthetic inertia provision strategy using a battery energy storage system (BESS) integrated alongside solar PV. The proposed method dynamically compensates for the loss of inertia by considering the variability of solar PV output due to changes in irradiance and temperature. …

Power-Beaming: Wireless Energy Transfer Using Lasers, Spencer L. Barnett

ATU Scholars Symposium

The objective of the project is to implement a wireless energy transfer system utilizing laser technology. This system involves modulating the laser’s beam profile and spatial distribution through precise optical manipulation. The energy transmitted by the laser is captured by a photovoltaic array, commonly referred to as a solar panel, which is engineered to convert incident photons into direct current (DC) electrical power. The current challenge is to develop a reliable wireless energy transfer mechanism capable of operating over extended distances, thereby overcoming the constraints imposed by wired connections, particularly in environments where wiring is impractical, such as in space. …

Variation Of Membrane Electrode Assembly Catalyst Layer In Unitized Regenerative Fuel Cell, Yollanda Nurcholifah, Dedi Rohendi, Edy Herianto Majlan, Nirwan Syarif, Addy Rachmat, Dwi Hawa Yulianti, Nyimas Febrika S

Journal of Electrochemistry

A unitized regenerative fuel cell (URFC) is a device that may function reversibly as either a fuel cell (FC) or water electrolysis (WE). An important component of this device is the Membrane electrode assembly (MEA). Therefore, this study aimed to compare the performance outcomes of MEA using electrodes with single and three catalyst layers. This study measured Electrochemical Surface Area (ECSA), Electrochemical Impedance Spectroscopy (EIS), X-ray Diffraction analysis (XRD), and X-ray Fluorescence (XRF). Furthermore, the round-trip efficiency (RTE) of the MEA, as well as the performance in FC and WE mode, was measured. In comparison, The ECSA values of Pt-Ru/C …

Performance Of Co2/H2O Co-Electrolysis In A Flat-Tube Solid Oxide Electrolysis Cell Stack Under Air-Free Environment, Xiao-Hui Zhong, Fei Wang, An-Qi Wu, Bei-Bei Han, Jian-Xin Wang, Wan-Bing Guan

Journal of Electrochemistry

This work investigates the transient performance and stability of CO₂/H₂O co-electrolysis in an air-free environment using a flat-tube solid oxide electrolysis cell (SOEC) stack. The results show that the transient behavior of the stack with and without blowing gas in the air electrode is almost the same. With a current density of 0.67 A·cm⁻²@750 °C, the stack operated for over 200 h under co-electrolysis conditions with no air blowing, and the voltage drop rate of the stack was approximately 0.203%/100 hours. Microstructure analysis reveals significant loss of Ni particles and formation of an insulating …

Simultaneous Observations Of Irregular Sporadic E Structures Using The Lwa And A Dps4d, Kenneth S. Obenberger, C. A. Taylor, Jonah J. Colman, Eugene Dao, J. Dowell, J. D. Eccles, Daniel J. Emmons, C. T. Fallen, J. M. Holmes, G. B. Taylor

Faculty Publications

Multi-instrument studies have recently shed new light on the morphology of sporadic E, especially intense sporadic E. Here we present simultaneous observations of dense sporadic E (E_s) structures using the Long Wavelength Array (LWA) radio telescopes and a Digisonde Portable Sounder 4D (DPS4D). Our coordinated observations show that the LWA radio telescopes in central New Mexico can reliably locate regions of dense Es structures as they pass over a Digisonde located over 500 km away in Texas. The LWA appears to be most sensitive to the densest E_s structures, which also appear to contain irregularities with vertical …

Electrocatalytic Nitric Oxide Reduction To Yield Ammonia Over Fe3C Nanocrystals, Sen Lin, Lang Zhang, Tong Hou, Jun-Yang Ding, Zi-Mo Peng, Yi-Fan Liu, Xi-Jun Liu

Journal of Electrochemistry

Nitric oxide (NO), which generally originates from vehicle exhaust and industrial flue gases, is one of the most serious air pollutants. In this case, the electrochemical NO reduction reaction (NORR) not only removes the atmospheric pollutant NO but also produces valuable NH₃. Hence, through the synthesis and modification of Fe₃C nanocrystal catalysts, the as-obtained optimal sample of Fe₃C/C-900 was adopted as NORR catalyst at ambient conditions. As a result, the Fe₃C/C-900 catalyst showed an NH₃ Faraday efficiency of 76.5% and an NH₃ yield rate of 177.5 μmol·h^–1·cm^{–2 …}

Ordering Degree Regulation Of Pt2Nico Intermetallics For Efficient Oxygen Reduction Reaction, Chen-Hao Zhang, Han-Yu Hua, Jun-Hao Yang, Qian Zhang, Chang Yang, De-Li Wang

Journal of Electrochemistry

Alloying transition metals with Pt is an effective strategy for optimizing Pt-based catalysts toward the oxygen reduction reaction (ORR). Atomic ordered intermetallic compounds (IMC) provide unique electronic and geometrical effects as well as stronger intermetallic interactions due to the ordered arrangement of metal atoms, thus exhibiting superior electrocatalytic activity and durability. However, quantitatively analyzing the ordering degree of IMC and exploring the correlation between the ordering degree and ORR activity remains extremely challenging. Herein, a series of ternary Pt₂NiCo intermetallic catalysts (o-Pt₂NiCo) with different ordering degree were synthesized by annealing temperature modulation. Among them, the o-Pt …

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

Research On Underground Coal Gasification From 2023 To 2024: A Systematic Review, Qin Yong, Yi Tongsheng, Wang Lingxia

Coal Geology & Exploration

Background The industrialization of underground coal gasification (UCG) technology presents a potential solution for securing the supply of clean energy. The latest wave of exploration into UCG is currently gaining momentum. Methods This review systematically organizes domestic and international literature, expatiates the advances in research on UCG from 2023 to 2024, analyzes the primary challenges in its development, and proposes key areas for future exploration. Advances Transformative technological advancements in the development and utilization of coal energy based on UCG have been proposed. The development of an integrated, synergistic UCG – coalbed methane – carbon capture, utilization, and storage (UCG–CBM–CCUS) …

Evolutionary Pattern And A Calculation Method Of In Situ Gas Pressure Based On Pressure-Retaining Coal Cores, Gao Mingzhong, Song Jie, Cui Pengfei, Li Yongcheng, Wang Zhipeng, Zhou Xuemin, Li Ju, Hao Zongxin, Hao Haichun

Coal Geology & Exploration

Objective and Methods The in situ gas pressure of coal seams represents a crucial parameter for the safe production of coal mines and the assessment of coalbed methane (CBM) resources. To overcome current limitations in determining the in situ gas pressure, such as prolonged measurement cycles and the influence of multiple parameters on the measurement results, this study conducted isothermal adsorption and volumetric expansion desorption experiments on pressure-retaining coal cores with varying moisture contents using a self-constructed experimental system for gas pressure evolution in pressure-retaining coal cores. As a result, the evolutionary pattern of gas pressure in pressure-retaining coal cores …

Key Technologies For Surface Control Of Gas Dynamic Disasters In Coal Mines And Their Application, Wang Bo, Xu Fengyin, Liu Wenge, Shao Sihua, Wang Ning, Wen Jiandong, Cheng Guoxi, Qu Zhenghui, Xie Yadong, Han Jiaye, Li Zhi, Xu Bo, Yang Weihua, Zhang Yiteng, Li Changxing

Coal Geology & Exploration

Objective and Significance As the coal mining depth increases, coal mining faces increasingly prominent challenges including coal and gas outbursts, rock bursts, and compound dynamic disasters. Deepening the understanding of disaster-causing mechanisms and developing diversified prevention and control technologies are significant for the safe production of coal mines. Employing the key technologies for coalbed methane (CBM) production to control gas-related dynamic disasters is an inevitable course for the safe production of coal mines. However, large-scale, suitable technology systems are yet to be developed. Methods From the perspective of the application of key technologies for surface CBM production, this study systematically …

Microseismic Monitoring And Assessment Of Segmented Hydraulic Fracturing Of Horizontal Wells In Coal Seam Roofs, Li Quangui, Peng Shuyue, Liang Yunpei, Li Wenxi, Qian Yanan, Cheng Chunhui, Yu Changjun, Zhan Jinfei

Coal Geology & Exploration

Background Microseismic monitoring, a non-destructive monitoring technique, has been extensively applied in the hydraulic fracturing performance assessment of coal seams. However, little attention is paid to the vertical wave velocity gradients in media in the same layer during the construction of layered wave velocity models. This leads to limited precision of travel time calculation and microseismic source localization, thus affecting the assessment accuracy of the hydraulic fracturing of coal seams. Objective and Methods Based on the coal seam segmented hydraulic fracturing project in a mine in Anhui, this study proposes an improved velocity model based on the Universal Kriging interpolation …

Reflections And Implementation Strategies For Constructing A Standard System For Deep Coalbed Methane Exploration And Exploitation, Chen Xinjun, Liu Zengqin, Shen Baojian, Zhao Shihu, Zhang Jiaqi, Ye Jincheng

Coal Geology & Exploration

Objective Deep coalbed methane (CBM; burial depths: > 1500 m) in China holds considerable resource potential. As a strategic clean energy, deep CBM is exhibiting increasingly high value of exploitation and utilization. This is of great practical significance for China’s energy structure transformation and the achievement of peak carbon dioxide emissions and carbon neutrality in the country. In recent years, breakthroughs have been made in deep CBM exploration in basins such as Ordos, Sichuan, and Junggar, with a single-well daily gas production exceeding 100 000 m³, marking the initial achievement of large-scale deep CBM exploitation. However, the existing standard …

Dynamic Gas Supply Mechanism And Theoretical Production Modes Of Free Gas-Rich Deep Coal Reservoirs, Chen Shida, Zhang Taiyuan, Tang Dazhen, Xu Hao, Tao Shu, Li Song, Tang Shuling

Coal Geology & Exploration

Objective and Methods The production processes of adsorbed and free gases and the dynamic partitioning mechanism behind the production efficiency of both gas types are critical scientific issues to be addressed urgently in the exploration and production of deep coalbed methane (CBM). Based on the test and assay data of cores from exploration wells, this study systematically analyzed the theoretical production of deep CBM resources. By integrating the building of mathematical and numerical models, carbon isotope monitoring of methane, and the analysis of production curves, this study revealed the spatiotemporal evolutionary processes of production-induced pressure drop expansion, adsorbed gas desorption, …

An Experimental Study Of Ch4 Displacement By Co2 Under Varying Initial Reservoir Pressures, Xu Jiang, Jiang Shiyu, Peng Shoujian, Wang Zhonghui, Chen Jiaxuan, Niu Huiting

Coal Geology & Exploration

Objective This study aims to reveal the evolutionary patterns of reservoir parameters during the CO₂-enhanced coalbed methane (CO₂-ECBM) recovery and the impact of initial reservoir pressure on CBM recovery by gas injection. Methods Based on the multi-field coupling-based physical simulation experiment system of gas injection into coal seams for production growth, this study conducted experiments of CH₄ displacement by CO₂ under a constant gas injection pressure of 2.0 MPa and initial reservoir pressures of 1.5 MPa, 1.0 MPa, and 0.5 MPa. Accordingly, this study explored the spatiotemporal evolutionary patterns of multiphysical field parameters such …

Parameter Optimization For Multistage Horizontal Well Fracturing Based On Multi-Cluster Perforation For Deep Coal Measure Gas: A Case Study Of The Jurassic Baijiahai Area In The Junggar Basin, Wang Bo, Jin Chenghong, Liu Jiang, Wang Zhiwei, Li Shenjian, Sheng Mao

Coal Geology & Exploration

Objective The multistage horizontal well fracturing based on multi-cluster perforation has emerged as an effective approach for the efficient production of deep coal-measure gas (CMG). However, deep coals feature unique rock mechanical properties, fluid loss characteristics of reservoirs, and microfracture developmental characteristics, which differ significantly from those of unconventional shales, tight sandstones, and shallow coals. As a result, existing fracturing experience cannot be directly applied, highlighting the investigation of fracturing parameter optimization tailored for deep CMG production.Methods Focusing on deep CMG reservoirs in the Baijiahai area within the Junggar Basin, this study constructed a model of multistage horizontal well …

Measures And Effects Of Eco-Geological Restoration In Well No.4 In The Muli Mining Area, Qinghai Province, China, Zhao Xin, Wang Tong, Wang Weichao, Li Congcong, Li Fei, Jiang Zhikun, Li Jin

Coal Geology & Exploration

Objective The Muli mining area, located in the hinterland of the Qilian Mountains, Qinghai Province, serves as the source of the Datong River—a major tributary of the Yellow River. This area falls within the alpine permafrost region, exhibiting a sensitive, fragile ecosystem. In the early 21st century, disordered coal mining in this area has caused ecological damage. This has notably posed four challenges in the ecological restoration of well No.4 in this area: (1) high, steep, and unstable slopes of spoil heaps; (2) a large volume of water accumulating in mining pits; (3) permafrost excavation and destruction, and (4) land …

Advances In Research On Lithium In Coal-Bearing Strata And Its Isotopes, Zhang Yun, Wei Yingchun, Cao Daiyong, Li Xin, Jin Liangliang, Dong Bo, Wang Xin

Coal Geology & Exploration

Significance Lithium serves as a significant strategic metal in emerging industries, and lithium isotopes have become crucial geochemical tracers due to their pronounced mass-dependent fractionation effects. Therefore, lithium minerals in coal-bearing strata have emerged as a priority in recent exploration of strategic metallic mineral resources. Investigating the isotopic composition and variation of lithium in coal-bearing strata helps reveal the sources, migration, and enrichment process of lithium while also providing a theoretical basis for lithium exploration and exploitation in coal-bearing strata. Advances This study offers a summary of advances in research on lithium in coal-bearing strata and its isotopes from three …