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A possible solution for noise attenuation material for urban buses: The downtown São Paulo case study

Noise and Vibration Worldwide 2025年第3期56卷 137-147页

作者： Monteiro, Elvis C Avila, Antonio F Division Stellantis Betim Brazil Mechanical Engineering Graduate Studies Program Universidade Federal de Minas Gerais Belo Horizonte Brazil Department of Mechanical Engineering and Mechanical Engineering Graduate Studies Program Universidade Federal de Minas Gerais Belo Horizonte Brazil

Urban buses, particularly in large cities, are exposed to significant noise pollution. This paper presents a new family of materials at the micro/nano level designed for urban noise attenuation, specifically for application in urban buses. Melamine foam is combined in series with nanomembranes, creating a composite material that functions as a Helmholtz resonator. As sound waves pass over the nanomembranes, they are disturbed, and the sound resonates within the melamine foam. This interaction reduces the energy of the sound waves and enhances the noise absorption coefficient. In ten cases studied, the average sound absorption coefficient was approximately 89%, with peak frequencies ranging from 2400 Hz to 4300 Hz. The average thickness of the nanomembranes was around 5.0 µm, while the melamine foam had a thickness of 13 mm. The mean noise reduction achieved was about 11 dB, which depends on factors such as the morphology, thickness, and pore size of the nanomembranes. A case study conducted in downtown São Paulo demonstrated that applying these materials to urban buses can significantly reduce interior noise levels. Finally, the proposed system is fully scalable and adaptable for various applications where acoustic insulation is required. © The Author(s) 2025.

关键词： Noise pollution

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The development of video laryngoscope via additive manufacturing for use in a pre-hospital environment

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Research on Biomedical engineering 2024年第1期40卷 15-23页

作者： Alves, Marcio Allan Foggiatto, Jose Aguiomar Berti, Lucas Freitas Ulbricht, Leandra Graduate Program in Biomedical Engineering Universidade Federal Tecnológica do Paraná Curitiba Brazil Graduate Program in Mechanical and Materials Engineering Universidade Federal Tecnológica do Paraná Curitiba Brazil

Purpose: Due to failures that occur during intubation, some authors advocate that intubation should always be done with a video laryngoscope. What makes the implementation of this recommendation difficult, especially in developing countries, is the high price of the device. Thus, the objective of this study is to present a low-cost video laryngoscope developed via additive manufacturing, being the first device to have the safety parameters duly tested according to the ISO 7673:2020 standard. Methods: A video laryngoscope with a Macintosh-type rigid blade was developed. After modeling it in the CAD-3D SolidWorks® program, the prototype was printed in PLA (polylactic acid), and load and fatigue tests were carried out with the MTS 810/793 testing machine. Results: The main results were an improvement in ergonomics (with a better fixation of the camera wire and camera positioning). Load and fatigue tests showed compliance with the requirements of the ISO 7673:2020 standard. The first is that when subjected to a traction force of 65 N, the center of illumination must not move more than 10 mm (the average movement was only 3.95 mm). The second is that when subjected to a traction force of 150 N, the laryngoscope blade must not break (348 N of load was applied and the piece resisted without breaking). Conclusion: It was shown that the Macintosh-type PLA video laryngoscope has the potential to become a safe and low-cost tool in the emergency intubation arsenal. © The Author(s), under exclusive licence to The Brazilian Society of Biomedical engineering 2023.

关键词： 3D printing

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Negative Stiffness Mechanism on An Asymmetric Wave Energy Converter by Using A Weakly Nonlinear Potential Model

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China Ocean engineering 2024年第4期38卷 689-700页

作者： Sunny Kumar POGULURI Dongeun KIM Yoon Hyeok BAE Department of Ocean Engineering IIT MadrasChennaiIndia Multidisciplinary Graduate School Program for Wind Energy Jeju National UniversityJejuRepublic of Korea Mechanical and System Design Engineering Hongik UniversitySeoulRepublic of Korea

Salter's duck,an asymmetrical wave energy converter(WEC)device,showed high efficiency in extracting energy from 2D regular waves in the past;yet,challenges remain for fluctuating wave *** can potentially be addressed by adopting a negative stiffness mechanism(NSM)in WEC devices to enhance system efficiency,even in highly nonlinear and steep 3D waves.A weakly nonlinear model was developed which incorporated a nonlinear restoring moment and NSM into the linear formulations and was applied to an asymmetric WEC using a time domain potential flow *** model was initially validated by comparing it with published experimental and numerical computational fluid dynamics *** current results were in good agreement with the published *** was found that the energy extraction increased in the range of 6%to 17%during the evaluation of the effectiveness of the NSM in regular *** irregular wave conditions,specifically at the design wave conditions for the selected test site,the energy extraction increased by 2.4%,with annual energy production increments of approximately *** findings highlight the potential of NSM in enhancing the performance of asymmetric WEC devices,indicating more efficient energy extraction under various wave conditions.

关键词： asymmetric wave energy converter negative stiffness mechanism weakly nonlinear potential flow power

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Design and Performance Comparison of Current References for a 32-bit Microcontroller Using 22nm Technology 16

Design and Performance Comparison of Current References for ...

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16th IEEE Latin American Symposium on Circuits and Systems, LASCAS 2025

作者： Barcelos, Eduardo A. Campagnucci, Pamela R. A. N. Munoz, Daniel M. Amaral, Wellington A. Haddad, Sandro A. P. Mechatronics Graduate Program Faculty of Technology Department of Mechanical Engineering Electronics Engineering Undergraduate Program University of Brasilia Faculty of Gama DF Brasilia Brazil

ISBN: (纸本)9798331522124

With the advancement of semiconductor technologies, the need for efficient power management solutions in integrated systems, such as RISC-V architecture-based microcontrollers, becomes increasingly critical. However, there is a lack of studies comparing current reference architectures in terms of performance and robustness, particularly in 22nm technologies. In this paper, we present a comparative analysis of two current reference designs implemented in the same technology-referred to as Reference Design A and Reference Design B. We focus on their approaches to thermal compensation, supply stability, and layout optimizations. Through simulations and experimental tests, we evaluate the performance of each design within a power management system that includes DC-DC converters and LDO regulators. Our results indicate that Design A exhibits superior power supply rejection with a PSRR of -85 dB, while Design B demonstrates enhanced energy efficiency and thermal stability, achieving a nominal current of 5.14 μA and a temperature coefficient of 16.21 ppm. These findings underscore the importance of balancing energy efficiency, thermal stability, and power supply variation rejection when selecting current references for low-power, high-reliability applications, such as those in the Internet of Things (IoT). © 2025 IEEE.

关键词： Integrated circuit layout

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Simulation of a Prototype of Individual Portable Air Purifier

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Defect and Diffusion Forum 2023年 427卷 179-192页

作者： Ló Guiot, Lucas Zinani, Flávia Schwarz Franceschini Roberto Wander, Paulo Mechanical Engineering Graduate Program Universidade do Vale do Rio dos Sinos UNISINOS São Leopoldo Brazil

Covid-19 is a highly contagious aero-transmissible virus. Even after two years of its emergence, new strains appear that require strengthening security measures such as social distancing, the use of masks, etc. It is crucial to prevent contamination, and care for the sanity of the air in closed environments, occupied by two or more people. Aerosols expelled by contaminated individuals dissolve in environments and can contaminate individuals regardless of their location. In this project, an air purifier for individual use was proposed to mitigate the risk of contamination by Covid-19 in closed environments. The equipment has been developed and prototyped, but has yet to be presented in the scope of this article. In this phase of the project, a study was conducted through numerical simulation to understand the effect of using this purifier on air circulation and its scope in the environment. Nine scenarios were developed: five two-dimensional and four three-dimensional, subject to different conditions: (i) closed environment, (ii) air infiltration through doors and windows, (iii) air-conditioner use, and purifier use. In individual use of the purifier, even if it is approximately 50 cm from the person in the room, the curtain of "clean air" coming from the purifier has become ineffective due to the existence of another, more intense outlet. The scenario with the airflow from the air-conditioner showed that the higher intensity of the airflow compared to the prototype purifier's airflow, meant that the prototype's airflow could not protect the user from the theoretically contaminated air mixed in the room. When the simulation of the use of the purifier was not done together with the air-conditioner runoff, the purifier proved effective in providing clean air and "protecting" the user with a wind curtain. However, even when the purified air cannot directly protect the user, the effects of the purifier can be beneficial by reducing the contamination of the air in the roo

关键词： Computational fluid dynamics

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A 22nm CMOS PFM Buck Converter Used in a 32-Bit RISC-V Microcontroller for IoT Applications 16

A 22nm CMOS PFM Buck Converter Used in a 32-Bit RISC-V Micro...

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16th IEEE Latin American Symposium on Circuits and Systems, LASCAS 2025

作者： Oliveira, Luiz H. N. Amaral, Wellington A. Haddad, Sandro A. P. Munoz, Daniel M. Barcelos, Eduardo A. Sotero, Vinicius V. M. Jonhson, Emmanuel K. M. Campagnucci, Pamela R. A. N. Lima, Luis V. N. Electronics Engineering Undergraduate Program Faculty of Gama Brazil Mechatronics Graduate Program University of Brasilia Faculty of Technology Department of Mechanical Engineering DF Brasilia Brazil

ISBN: (纸本)9798331522124

The demand for efficient power management solutions in electronic devices has increased significantly, especially for microcontrollers operating in low-power modes. This article presents the design and implementation of a Pulse Frequency Modulation (PFM)-based buck converter for applications in 32-bit microcontrollers using 22nm CMOS technology. The methodology involves the development of a Constant On Time (COT) architecture that maintains a fixed duration for the activation of the high-side MOSFET, using a monostable multivibrator to generate the necessary timing signals. The converter's performance was simulated under various load conditions and process corners to evaluate its efficiency and output characteristics. The results show that the proposed buck converter achieves high efficiency, with peak values above 95%, while maintaining a low output ripple. Specifically, the converter exhibits an efficiency of 93.4% at a load of 1mA, with output ripple voltages as low as 2.20 mV under ideal conditions. The contributions of this work lie in the advancement of PFM converter technology for modern microcontroller applications, demonstrating the potential of 22nm CMOS processes to improve power efficiency and performance. © 2025 IEEE.

关键词： CMOS integrated circuits

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Enhancing the Versatility and Performance of Soft Robotic Grippers, Hands, and Crawling Robots Through Three-Dimensional-Printed Multifunctional Buckling Joints

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Soft Robotics 2024年第5期11卷 741-754页

作者： Yang, Chih-Wen Ou Yu, Shao-Yi Chan, Che-Wei Tseng, Chien-Yao Cai, Jing-Fang Huang, Han-Pang Juang, Jia-Yang Department of Mechanical Engineering National Taiwan University Taipei Taiwan Department of Mechanical Engineering University of California at Berkeley BerkeleyCA United States Program in Nanoengineering and Nanoscience Graduate School of Advanced Technology National Taiwan University Taipei Taiwan

Soft robotic grippers and hands offer adaptability, lightweight construction, and enhanced safety in human–robot interactions. In this study, we introduce vacuum-actuated soft robotic finger joints to overcome their limitations in stiffness, response, and load-carrying capability. Our design—optimized through parametric design and three-dimensional (3D) printing—achieves high stiffness using vacuum pressure and a buckling mechanism for large bending angles (>90◦) and rapid response times (0.24 s). We develop a theoretical model and nonlinear finite-element simulations to validate the experimental results and provide valuable insights into the underlying mechanics and visualization of the deformation and stress field. We showcase versatile applications of the buckling joints: a three-finger gripper with a large lifting ratio (*96), a five-finger robotic hand capable of replicating human gestures and adeptly grasping objects of various characteristics in static and dynamic scenarios, and a planar-crawling robot carrying loads 30 times its weight at 0.89 body length per second (BL/s). In addition, a jellyfish-inspired robot crawls in circular pipes at 0.47 BL/s. By enhancing soft robotic grippers’ functionality and performance, our study expands their applications and paves the way for innovation through 3D-printed multifunctional buckling joints. © Mary Ann Liebert, Inc.

关键词： Grippers

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Improvement of Localization Algorithm for Indoor and Outdoor Navigation of Autonomous Robots

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Journal of Institute of Control, Robotics and Systems 2025年第5期31卷 502-509页

作者： Cho, Joonhyuk Kim, Bongsang Moon, Heechang Industrial Convergence Interdepartmental Program Autonomous Vehicle Intelligent Robotics The Graduate School of Hongik University Korea Republic of Mechanical & System Design Engineering Hongik University Korea Republic of

Location estimation for waypoint-based autonomous driving robots primarily relies on SLAM (Simultaneous Localization and Mapping) and GNSS (Global Navigation Satellite System) technologies. GNSS performs well in open areas but struggles with signal issues, while SLAM offers high accuracy in feature-rich environments but faces challenges in open spaces. This study integrates SLAM and GNSS, enabling seamless switching between systems when one encounters difficulties. The combined system ensures consistency by aligning coordinate systems and directional data. Experiments in indoor, forest, and open environments demonstrate that the switching algorithm enables stable autonomous driving in diverse conditions, effectively leveraging the strengths of both systems. © ICROS 2025.

关键词： Global positioning system

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Comparison of Bioinspired MLP Controllers for Mobile Robots Obstacle Following/Avoidance

Comparison of Bioinspired MLP Controllers for Mobile Robots ...

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2024 IEEE Latin American Conference on Computational Intelligence, LA-CCI 2024

作者： Luiz, Matheus De S. Pastrana, M.A. Da Silva, Lukas. A. Campagnucci, Pamela. R. A. N. Mendoza-Penaloza, Jose Benevides, Rafael R.L. Munoz, Daniel M. University of Brasilia Mechatronics Graduate Program Department of Mechanical Engineering Brasilia Brazil University of Brasilia Faculty of Gama Electronics Engineering Undergraduate Program Brasilia Brazil

ISBN: (纸本)9798350374575

Proportional, integral, and derivative (PID) controllers have been widely adopted for industrial applications. However, these controllers are not very efficient for non-linear systems. Artificial neural networks (ANN) based on the Multilayer Perceptron (MLP) have great potential to replace PID controllers due to their polynomial structure, allowing complex non-linear systems to be controlled. This article introduces the integration of four MLPs as alternatives to a traditional PID controller. These MLPs were trained through four bioinspired algorithms tailored for following tasks in mobile robots. The bioinspired algorithms employed for MLP network training include Particle Swarm Optimization (PSO), Grey Wolf Optimization (GWO), Month-Flame Optimization (MFO), and Artificial Hummingbird Algorithm (AHA). A comparative analysis was conducted between these MLPs and a classic PID controller, focusing on parameters such as overshoot (OS), settling time (ST), and steady-state error for different simulated scenarios. © 2024 IEEE.

关键词： Particle swarm optimization (PSO)

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Energy consumption simulation for tool path using model of feed drive system 38

Energy consumption simulation for tool path using model of f...

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38th Annual Meeting of the American Society for Precision engineering, ASPE 2023

作者： Kawamura, Naru Hayashi, Akio Morimoto, Yoshitaka Graduate School of Engineering Mechanical Engineering Program Kanazawa Institute of Technology Ishikawa Nonoichi Japan

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