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Thermodynamic and Environmental Assessment of Low-GWP Alternative Refrigerants for Domestic Cooling

Journal of The Institution of Engineers (India): Series C 2023年第2期104卷 377-383页

作者： Islam, Md. Amirul Rupam, Tahmid Hasan Hosan, Shahadat Saha, Bidyut Baran Institute for Materials Chemistry and Engineering Kyushu University Kasuga-Koen 6-1 Kasuga-Shi Fukuoka816-8580 Japan Department of Electrical and Electronics Engineering Bangabandhu Sheikh Mujibur Rahman Science and Technology University Gopalganj8100 Bangladesh Kyushu University 744 Motooka Nishi-Ku Fukuoka819-0395 Japan Kyushu University Program for Leading Graduate School Green Asia Education Center Kyushu University Fukuoka Japan Department of Mechanical Engineering Kyushu University 744 Motooka Nishi-Ku Fukuoka819-0395 Japan

Nearly two billion air-conditioning (AC) units are currently being used for space cooling worldwide. The majority of these ACs use R134a as the working fluid, a greenhouse gas (GHG) with a global warming potential (GWP) of 1300 kg-CO2-eq. According to the rules set by the world environment safety organizations, the GWP of domestic air-conditioning systems must not exceed 750 kg-CO2-eq. Hence, the R134a must be phased out by 2025, and an alternative refrigerant with similar thermodynamic properties yet low GWP is required. Therefore, the authors have investigated several potential binary/ternary refrigerant blends in this study. Among the studied refrigerants, R445A, R30A, and NPB2 (newly proposed blend: 8% R152a + 92% R1234yf) can reduce 90–99% global warming impact (more than 200 million tonnes of CO2 emission equivalent) caused by the domestic air-conditioning systems every year. © 2023, The Institution of Engineers (India).

关键词： Refrigerants

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Development of an Embedded System for Monitoring a Solar Power Plant in the Amazon Region

Development of an Embedded System for Monitoring a Solar Pow...

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IEEE/IAS International Conference on Industry Applications (INDUSCON)

作者： Yasmim Lisboa Lucas Santos Ellen Lobato Wellington Fonseca Kaylane Silva Iris Rodrigues Marcelo De Oliveira e Silva Institute of Technology Federal University of Pará Pará Brazil Mechanical Engineering Graduate Program Federal University of Para Belém Brazil

The present work deals with the development of an embedded Internet of Things (IoT) system for monitoring the temperature of a photovoltaic system at different points, to enable the analysis of the efficiency of the solar system based on the thermal effect, considering the characteristics climate in the Amazon region. The module created was built and installed in a photovoltaic solar plant located at the Federal University of Para. For the analyses, the regions of interest for monitoring the panels were considered, which are: the surface of the generator module in contact with the sun; the shaded area of the panel and the ambient temperature. Satisfactory results were obtained regarding the operation of the embedded system, which proved to be ideal for monitoring solar panels due to the ease of updating, communication, and data visualization.

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Heterojunction and co-catalyst engineering of bismuth vanadate by nickel molybdenum oxide and carbon quantum dot decorations for photoelectrochemical water splitting

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International Journal of Hydrogen Energy 2024年 51卷 1099-1108页

作者： Kuo, Tsung-Rong Chiou, Yu-Tai Huang, Hsiao-Wen Kongvarhodom, Chutima Saukani, Muhammad Yougbaré, Sibidou Chen, Hung-Ming Lin, Lu-Yin Graduate Institute of Nanomedicine and Medical Engineering College of Biomedical Engineering Taipei Medical University Taipei11031 Taiwan International PhD Program in Biomedical Engineering College of Biomedical Engineering Taipei Medical University Taipei11031 Taiwan Department of Chemical Engineering and Biotechnology National Taipei University of Technology Taipei Taiwan Department of Chemical Engineering King Mongkut's University of Technology Thonburi 126 Pracha-u-thit Toong-kru Bangkok10140 Thailand Department of Mechanical Engineering Faculty of Engineering Universitas Islam Kalimantan MAB Jl. Adhyaksa No. 2 Banjarmasin70124 Indonesia /Nanoro 03 B.P 7192 Ouagadougou03 Burkina Faso Gingen technology Co. LTD. Rm. 7 10F. No.189 Sec. 2 Keelung Rd. Xinyi Dist. Taipei11054 Taiwan

Improving the charge diffusion length and water oxidation kinetics of bismuth vanadate (BiVO4) is essential to achieve better photoelectrochemical catalytic ability for water oxidation. Establishing heterojunctions and incorporating co-catalysts with BiVO4 create facile charge transfer paths and generate more water oxidation reactions. In this work, nickel molybdenum oxide (NM) and carbon quantum dot (CQD) are firstly deposited on BiVO4 by hydrothermal and soaking processes to design an efficient co-catalyst/photocatalyst system for water oxidation. The depositing amount of CQD is optimized to balance contributions of CQD and NM as the hole sink and the light-to-electron generator, respectively. The highest photocurrent densities of 2.2 and 3.9 mA/cm2 are achieved for BiVO4/NM/CQD in the electrolyte without and with hole scavenger, respectively. The BiVO4 electrode only shows a photocurrent density of 1.2 mA/cm2 in the electrolyte without hole scavenger. The best photoelectrochemical catalytic ability of BiVO4/NM/CQD is approached by the reduced charge-transfer resistance and charge recombination as well as the enhancement on carrier densities. The excellent long-term stability with the photocurrent retention of 90% under illumination for 24 h is also obtained for BiVO4/NM/CQD. This study opens a blueprint on designing efficient catalysts for water oxidation by incorporating heterojunction and co-catalyst materials simultaneously. © 2023 Hydrogen Energy Publications LLC

关键词： Heterojunctions

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Efficiently catalyzing photo-oxidation of water by surface engineering of bismuth vanadate with nickel molybdenum oxide coverages

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International Journal of Hydrogen Energy 2024年 51卷 613-622页

作者： Kuo, Tsung-Rong Huang, Hsiao-Wen Kongvarhodom, Chutima Saukani, Muhammad Yougbaré, Sibidou Chen, Hung-Ming Lin, Lu-Yin International PhD Program in Biomedical Engineering College of Biomedical Engineering Taipei Medical University Taipei11031 Taiwan Graduate Institute of Nanomedicine and Medical Engineering College of Biomedical Engineering Taipei Medical University Taipei11031 Taiwan Department of Chemical Engineering and Biotechnology National Taipei University of Technology Taipei Taiwan Department of Chemical Engineering King Mongkut's University of Technology Thonburi 126 Pracha-u-thit Toong-kru Bangkok10140 Thailand Department of Mechanical Engineering Faculty of Engineering Universitas Islam Kalimantan MAB Jl. Adhyaksa No. 2 Banjarmasin70124 Indonesia /Nanoro 03 B.P 7192 Ouagadougou 03 Burkina Faso Gingen Technology Co. LTD. Rm. 7 10F. No.189 Sec. 2 Keelung Rd. Xinyi Dist. Taipei11054 Taiwan

Bismuth vanadate with suitable band edges is one of the efficient photocatalysts for water oxidation. Establishing heterojunction can improve electron diffusion lengths and photocatalytic ability of BiVO4. In this work, nickel molybdenum oxide (Ni–Mo–O) and BiVO4 heterojunction is established by the hydrothermal process with different nickel to molybdenum precursor ratios. The Ni–Mo–O/BiVO4 electrode is applied as photoanodes for water oxidation. The growth mechanism of Ni–Mo–O on BiVO4 surface is proposed. The Ni–Mo–O deposition amount is optimized regarding to light absorbance and charger transportation. The largest photocurrent density of 1.72 mA/cm2 at 1.23 VRHE is obtained for the optimal NiMoO4/BiVO4 electrode (NM12) in the electrolyte without hole scavenger, while the pure BiVO4 electrode only shows a photocurrent density of 0.90 mA/cm2. The NM12 electrode even presented an impressive photocurrent density of 5.39 mA/cm2 at 1.23 VRHE in the electrolyte with the hole scavenger, owing to the abundant active sites and higher light absorbance as well as the favorable synergistic effects from its suitable Ni to Mo ratio. The NM12 electrode also shows excellent long-term stability with the photocurrent retention of 83% after illumination for 6500 s. This work opens a blueprint for establishing a novel heterojunction with the adjustable metal ratio and coverage on BiVO4. © 2023 Hydrogen Energy Publications LLC

关键词： Heterojunctions

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Manta Ray Foraging Optimization Approaches on Multivariable PID Controller Tuning

Manta Ray Foraging Optimization Approaches on Multivariable ...

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Congress on Evolutionary Computation

作者： Yan Lieven Souza Luúio Luiza Scapinello Aquino Da Silva Viviana Cocco Mariani Leandro Dos Santos Coelho Electrical Engineering Graduate Program (PPGEE) Federal University of Parana (UFPR) Curitiba Brazil Department of Electrical Engineering Mechanical Engineering Graduate Program (PPGEM) Pontifical Catholic University of Parana (PUCPR) and Federal University of Parana (UFPR) Curitiba Parana Brazil Department of Electrical Engineering Industrial and Systems Engineering Graduate Program (PPGEPS) Pontifical Catholic University of Parana (PUCPR) and Federal University of Parana (UFPR) Curitiba Brazil

This work presents a performance comparison between the newly developed Manta Ray Foraging Optimization (MRFO) and two different variants created for tuning a decentralized fractional order proportional-integral-derivative (FOPID) controller for a multiple-input multiple-output (MIMO) application. The application consists of a ball mill pulverizing system to pulverize coal and maximize fuel efficiency. MRFO and its applications have the task of finding the optimal controller variable values to control the system's temperature and pressure. The MRFO is a metaheuristic based on the behavior of manta rays, and although it shows efficient performance it may be improved through the use of techniques which generate new variants of the algorithm. Two techniques were used in the de-velopment of new variants: Quantum mechanics and opposition-based learning. The three different versions of MRFO were used to minimize a custom fitness function which is a combination of the integral time squared error (ITSE) and the overshoot of the system response. Simulations were carried using Simulink and Matlab softwares. For analyzing the performances, statistical measures such as minimum, maximum, best, mean, median, and standard deviation of the fitness function over 50 runs were used. Additionally, the different variants were also compared for minimizing 10 benchmark functions. The results show that the use of the previously mentioned techniques improve the performance of the original MRFO in optimizing the FOPID to control the ball mill pulverizing system.

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Teaching Control Theory using Mobile Robot Obstacle Following/Avoidance with CoppeliaSim and MFO Algorithm.

Teaching Control Theory using Mobile Robot Obstacle Followin...

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IEEE Latin American Robotics Symposium, LARS

作者： M. A. Pastrana J. Bautista Jose Mendoza-Peñaloza L. H. Oliveira D. A. Mendes Daniel M. Muñoz Department of Mechanical Engineering Mechatronics Graduate Program University of Brasilia Brasilia DF Brazil Faculty of Engineering Systems Undergraduate Program Florencia University of the Amazonia Caquetá Colombia Faculty of Gama Electronics Engineering Undergraduate Program University of Brasilia Brasilia DF Brazil

The advancements in information and communication technologies have had a significant impact on the engineering educational system. Virtual laboratories are progressively being adopted to improve the way in which students interact with simulations for control systems. The enhancement of visualization and interaction offered by modern computers presents an opportunity to teach the theoretical foundation with a more organic approach. In addition, there are optimization algorithms that can be employed to designing controllers in an optimal way without having extensive knowledge in the area of control theory. This paper delineates the utilization of CoppeliaSim software, the Moth Flame Optimization (MFO) algorithm, and the EVA mobile robot for teaching control theory with Single-Input, Single-Output systems (SISO), for mobile robot obstacle following/avoidance application. The approach employs an online multi-language (Spanish and Portuguese) methodology for students without knowledge of control theory.

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Jet direction control using secondary flows

Jet direction control using secondary flows

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作者： Tamanoi, Y. Watanabe, Y. Kobayashi, R. Sato, K. Mechanical Engineering Program The Graduate School of Engineering Kogakuin University 1-24-2 Nishi-shinjuku Shinjuku-ku Tokyo163-8677 Japan

In recent years, studies on the fundamental principle of thrust vectoring using jets have been conducted with the aim of application to next-generation aircraft. Consequently, the improvement of aircraft motion performance is expected. Previously, a method using secondary flow with a Coanda surface was proposed for the direction control of the primary jet, and some valuable results were reported. The effect of ejection or suction on the traveling direction of the primary jet was examined. However, as many physical quantities dominate the phenomenon in this complicated situation, parametric studies are insufficient. The present study is a fundamental study of fluidic thrust vectoring. The effect of secondary injection or suction flow near the Coanda surface on the travel direction of primary jets was investigated parametrically using the momentum ratio, nozzle width ratio, etc. without changing the nozzle geometry. A larger deflection of the primary jet was observed because of the suction rather than ejection at the same momentum ratio. Furthermore, the effect of the slot width ratio on the dead zone where the traveling direction of the second jet does not depend on the momentum of the secondary flow was studied. © Published under licence by IOP Publishing Ltd.

关键词： Secondary flow

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A New Technique for Identification and Evaluation of Wear in Cupper Electrodes in Electrical Discharge Machining Using Acoustic Emission Signals

Research Square

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Research Square 2021年

作者： Ferreira, Samuel Soares Amorim, Fred Lacerda Júnior, Jánes Landre Maia, Luís Henrique Andrade Machado, Álisson Rocha Sales, Wisley Falco Mechanical Engineering Graduate Program MG Belo Horizonte Brazil Mechanical Engineering Graduate Program PR Curitiba Brazil Mechanical Engineering Graduate Program Uberlandia-MG Singapore

Electrical Discharge Machining (EDM) is an unconventional machining process based on removing material by successive electrical discharges. The tool electrode wear must be kept as minimal as possible to produce high precision components. This scope proposes the development of a new technique for identifying wear on electrodes and its evolution using acoustic emission (AE) signals. Therefore, EDM tests were performed on H13 steel parts with electrolytic copper tool electrodes under two different conditions with concomitant AE signals measurements. The following parameters were used in the first EDM test: voltage pulse duration time (te) of 150 μs;the time interval between two successive voltage pulses (to) of 14.84 μs;electrical current of 33 A;and positive polarity electrode. For the second test: duration of the voltage pulse (te) of 2 μs;the time interval between two successive voltage pulses (to) of 4.90 μs;electrical current of 18 A;and negative polarity electrode. In this way, a wear rate 28.3 times higher was obtained in the electrolytic copper electrode in the first test, more aggressive due to its parameters, for the same machining time compared to the second test. Finally, the wear of the tool electrodes was related to the AE signals from machining, initially in this study, the workpiece's mass loss was not verified. These signals were analyzed using the Short-Time Fourier Transform techniques and Spectral Entropy. The results showed that the signals using the new technique of relation respond to wear and are sensitive to the electrode's wear rate. © 2021, CC BY.

关键词： Wear of materials

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Multiband Patch Antenna Design Using Nature-Inspired Optimization Method

IEEE Open Journal of Antennas and Propagation

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IEEE Open Journal of Antennas and Propagation 2021年 2卷 151-162页

作者： Boursianis, Achilles D. Papadopoulou, Maria S. Pierezan, Juliano Mariani, Viviana C. Coelho, Leandro S. Sarigiannidis, Panagiotis Koulouridis, Stavros Goudos, Sotirios K. ELEDIA@AUTH Research Group School of Physics Aristotle University of Thessaloniki Thessaloniki54124 Greece Department of Electrical Engineering Federal University of Parana Curitiba80060-000 Brazil Industrial and Systems Engineering Graduate Program and Mechanical Engineering Graduate Program Pontifical Catholic University of Parana Curitiba80215-901 Brazil Department of Electrical and Computer Engineering University of Western Macedonia Kozani501 00 Greece Electrical and Computer Engineering Department University of Patras Patras26504 Greece

Radio frequency energy harvesting has attracted considerable interest as a technique of enabling self-powered wireless networks. This technique faces several challenges, such as the receiving and the rectifying modules of a rectenna system. Multiband antennas provide several comparative advantages against the goal of maximizing the amount of energy harvesting. In this work, we present a multiband microstrip patch antenna with three slits operating in the LoRaWAN (Long Range Wide Area Network) and the cellular (GSM-1800 and UMTS) communication frequency bands. A feasible solution of the antenna is obtained by the application of a recently introduced nature-inspired optimization technique, namely the Coyote Optimization Algorithm. The proposed antenna operates satisfactorily in the LoRaWAN (Long Range Wide Area Network) and the cellular (GSM-1800 and UMTS) communication frequency bands. Measured results of the proposed antenna exhibit an acceptable performance (multiband frequency operation, maximum gain of 3.94 dBi, broadside operation) and demonstrate features of operation, which make it a strong candidate for various RF energy harvesting applications. © 2020 IEEE.

关键词： Microstrip antennas

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Integrating a Small-Scale Adaptive Solar Drying Systems with Nichrome Wire for Processing Dried Moro-Moro Fish

Integrating a Small-Scale Adaptive Solar Drying Systems with...

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Sustainable Power and Energy Conference (iSPEC)

作者： Karell Keith P. Gulben Datu Al-Ashari J. Salat Basilio Corleone U. Boddie Liregine Sobretodo Cayme Niño Louie Reyes Boloron Reylina Garcia Tayactac Mechanical Engineering Program Mapúa Malayan Colleges Mindanao Davao Philippines Mapúa Malayan Colleges Mindanao School of Mechanical Manufacturing and Energy Engineering Mapúa University School of Graduate Studies Intramuros Manila Philippines Davao City Philippines Mapúa Malayan Colleges Mindanao Central Mindanao University Bukidnon Philippines School of Mechanical Manufacturing and Energy Engineering Mapúa University School of Graduate Studies Intramuros Manila Philippines

ISBN: (数字)9798350395075

ISBN: (纸本)9798350395082

This study evaluates a small-scale adaptive solar drying system using nichrome wire to enhance the drying process for Moro-moro fish. The nichrome wire's rapid heating accelerates drying, reduces exposure to pests, and mitigates issues like climate variations and uneven drying. Although mechanical dryers exist, their high costs and limited efficiency restrict use. This adaptable system provides a sustainable and effective method of preserving fish by optimizing drying through steady heat and moisture control.

关键词： Heating systems Moisture control Adaptive systems Costs Statistical analysis Climate variability Fish Wire

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