Vol. 3 No. 2 (2025)

Open Access

Article

Article ID: 2145

Traffic-based methodology to develop peak Heat Release Rate probability distributions for sizing road tunnels ventilation systems when using a probabilistic approach
by Sonia Fernandez, Charles Fleischmann, Daniel Nilsson, Alberto Fraile

Mechanical Engineering Advances, Vol.3, No.2, 2025;

DOI: https://doi.org/10.59400/mea2145

Road tunnels are a crucial part of today’s transport infrastructures worldwide. Among the installed systems, the tunnel ventilation is key, as in the case of fire, it establishes and keeps appropriate conditions for self-evacuation and emergency services operations. Recent works propose using a probabilistic approach to assess road tunnels ventilation systems’ capacity for fire scenarios. Under this approach, key design variables are defined based on probability distributions. From these distributions, the analysis uses the different possible values of the variables, including lower and upper limits as well as mean and characteristic values. The results obtained with this proposed probabilistic approach allow not only designers, but also tunnel operators and administrations, to quantify the reliability of the capacity of the ventilation system, assess its probability of failure, and define safety levels. This paper illustrates a methodology to define the design fire as a probability distribution for sizing road tunnels ventilation systems when applying the above-mentioned probabilistic approach. The methodology uses traffic information (crucial in road tunnels) and correlates it to peak Heat Release Rate (HRR) values from published reports by PIARC to obtain the design fire variable in terms of peak HRR probability distributions. The methodology is applied to two case study tunnels with different characteristics. The obtained results for the two tunnels are then compared and analyzed to peak HRR values normally recommended and used when sizing road tunnels ventilation systems to understand the uncertainty and sensitivity of the results.

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Open Access

Article

Article ID: 2534

Effect of inverse-square heat absorption on MHD natural convection flow in a vertical concentric annulus with radial and induced magnetic fields
by Muhammad Yusuf Muhammad, Yusuf Ya’u Gambo, Muhammad Auwal Lawan

Mechanical Engineering Advances, Vol.3, No.2, 2025;

DOI: https://doi.org/10.59400/mea2534

This study investigates the impact of inverse-square heat absorption on steady, fully developed laminar MHD natural convection flow within an infinite vertical concentric annulus under the influence of applied radial and induced magnetic fields. The governing transport equations in the model were transformed into a non-dimensional form, allowing for the derivation of unified analytical solutions for the velocity, temperature, magnetic field, and induced current density distributions for both isothermal and iso-flux on the inner cylinder of concentric annuli. The influence of key physical parameters in the model is illustrated through a comprehensive analysis of graphs and tables. The findings reveal that increasing the heat absorption parameter intensifies thermal gradients near the inner cylinder, while stronger magnetic fields suppress fluid motion, reducing mass flux and enhancing flow resistance. Mass flux and induced current density decrease as Hartmann number and heat absorption parameter increase, demonstrating the combined influence of thermal and electromagnetic forces. The magnetic field distributions and associated current densities exhibit pronounced attenuation near the inner cylinder under a higher Hartmann number. These findings highlight the intricate interaction between thermal and electromagnetic forces, offering valuable insights for applications in nuclear reactors, MHD power generation, and advanced cooling technologies. This study contributes to refining MHD-driven thermal management approaches for Advanced engineering systems.

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Open Access

Article

Article ID: 2474

Design method for intelligent robots applied to traditional CNC processing plants: An integrated system based on mechanical, circuit, and image recognition technologies
by Yung-Hsiang Chen, Sheng-Yan Pan

Mechanical Engineering Advances, Vol.3, No.2, 2025;

DOI: https://doi.org/10.59400/mea2474

This study aims to design an automated production assistance device for small to medium-sized traditional CNC factories. The goal is to provide a cost-effective auxiliary production tool that integrates seamlessly into existing machining environments. The design encompasses mechanical, circuit, and software components. Mechanically, the device features a robotic arm equipped with a camera for object recognition and gripping, utilizing real-time image processing to enhance efficiency and stability. The circuit design employs embedded devices and microcontrollers to create a low-power, high-performance control system that manages motor drive, sensor data collection, and image recognition. On the software front, the system uses OpenCV and You Only Look Once (YOLO) for object detection and identification to tackle complex industrial scenarios. The design also considers economic feasibility, making it suitable for effective application in small and medium-sized enterprises. Through detailed theoretical analysis and multi-stage system simulations, the intelligent robot system has been thoroughly validated for overall stability and practicality. The final product is an intelligent self-propelled cart with capabilities, supporting efficient automated production and the intelligent upgrade of traditional manufacturing industries. Such a system is expected to significantly enhance production line efficiency in variable environments, reduce reliance on manual labor, and promote the intelligent transformation of traditional factories.

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In the paper, the MATLAB-Simulink model of simulation of operation of the fast light innovative regional train from “Serbian Railways” in traction and braking mode is exposed where changes are observed: stator currents of three-phase traction motors, traction electric motor speeds and electric multiple units, electromagnetic torque on the rotor shaft of the traction electric motor, and direct current bus voltage. The model allowed review of the listed parameters for: different allowed values of contact network voltage and total voltage distortion at the place of connection of the electric multiple unit to the contact network; different mechanical loads of the electric multiple unit and traction electric motor; and different train speeds and rotations of traction electric motors. Appropriate conclusions were made through the analysis of the simulation results obtained.

This paper defines vehicles and buildings as main sources of United Kingdom (UK) carbon dioxide (CO₂) and seeks to cut such emissions using green hydrogen made from combined wind and solar energy. Combustion vehicles powered by fossil petroleum emit near half of UK climate-warming CO₂ while buildings heated by natural gas provide a third. First, current UK grid problems are defined: Electricity, gas and petroleum grids. Refueling green vehicles has been a particular problem. Then experiments on the private wire community of Keele University show how green hydrogen could integrate both green vehicles and buildings. Next, the model supply chain is planned and tested. Finally, experiments and calculations are outlined, analyzing the optimum system design criteria proposed. We conclude that economic green hydrogen can displace petroleum in vehicles, while powering buildings instead of natural gas. Also, the prospect in 2024 is that profits can be made all along the green hydrogen supply chain, such that new businesses involved in local private clean communities can cost less than the National Grid monopoly and other dominant fossil energy companies.

Presently, dynamic impacts occurrences caused by car crashes have been frequently reported. Statistical results from different articles indicate that vehicle crashworthiness of bridge pier supersedes the other events. However, majority of the published articles focusses on sustainability and finding severity of distressed pier due to impact correlating faster construction methods, like accelerated bridge construction (ABC). This article is an attempt to examine post impacted behavior of a commonly used connector in ABC for resisting short duration shock. Static and dynamic performance analyses of a connector embedded within a coupler system has been examined. A representative ABC pier with the standardized and selected material properties collected from manufacturer’s data has been utilized. Coupler composite materials consisting of a hollow uniform cross-section cast iron cylinder filled up with specified concrete grout conforms higher strength. The performance examination has been conducted by numerical modeling using finite element method (FEM). A commercially used software ANSYS has been utilized for carrying out the simulations. To investigate the post impact dynamic behavior, mesh-independent studies seems inevitable and hence are executed to evaluate dynamic impact factor (DIF). Sensitivity studies are carried out for validating results in precision. The DIF of the main reinforcing tensile steel embedded into the grout placed inside the connector has been determined. Results captured from simulations to identify material properties at plastic stage in sustaining such load have been conducted. The results provide significant information that aids opting for selecting suitable connectors for attaining help the design offices.