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SSRN 2022年

作者： Ayandotun, Wasiu B. Aziz, Abdul Rashid A. Ismael, Mhadi A. Mohammed, Salah E. Raheem, Ahmed T. Universiti Teknologi PETRONAS Bandar Seri Iskandar Perak 32610 Malaysia Mechanical Engineering Department Federal Polytechnic Kaura Namoda Zamfara State PMB 1012 Nigeria Mechanical Engineering Department College of Engineering and Architecture University of Bahri Khartoum1660 Sudan

A free-piston linear generator (FPLG) is an energy conversion device that can generate electrical energy utilizing different types of fuel. Natural gas fields with high carbon dioxide (CO2) content are being simulated for study, knowing that the presence of CO2 in natural gas contributes to a reduction in NOx emission while improving the compression ratio. This paper presents a comparative analysis of the performance and combustion characteristics of a spark ignition (SI) FPLG fuelled with two different fuels, namely compressed natural gas (CNG) and a mixture of CNG and CO2 (CNG-CO2). A test was conducted on the FPLG to study the engine performance and combustion at various lambda ratios. It is clarified that lambda variation significantly affects the piston motion and combustion of CNG and CNG-CO2, resulting in a variation of FPLG engine stability. When a lambda tends towards a rich mixture, the translator attains a peak velocity of 5.0 and 6.25 m/s, for the CNG-CO2 and CNG, respectively, resulting in output power (rms) of 257.2 and 295.7 W at λ = 0.86 and 0.85. Also, the presence of CO2 in CNG increases the compression ratio. The engine could attained ITE of 22.8% and 15.1% for CNG-CO2 and CNG, respectively. © 2022, The Authors. All rights reserved.

关键词： Carbon dioxide

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Heat Transfer and Pressure Loss Performance of Additively Manufactured Metamaterials in Annular Channels

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Energies 2025年第10期18卷

作者： Emanuele Vaglio Federico Scalzo Marco Sortino Luca Casarsa Polytechnic Department of Engineering and Architecture University of Udine Via delle Scienze 206 33100 Udine Italy

Additive manufacturing is revolutionizing the production of thermo-fluidic devices by enabling the creation of a wide variety of complex architectures, significantly enhancing performance and efficiency. Nevertheless, the range of structural types investigated to date remains limited, with most studies employing simplified methodologies and constrained operating conditions. This study explores the thermo-hydraulic performance of water-cooled annular channels incorporating BCC, Octahedral, and gyroid structures fabricated from AISI 316L stainless steel using Laser Powder Bed Fusion. The samples were experimentally tested across a broad spectrum of mass flow rates using a custom-designed test rig to evaluate heat transfer and pressure loss performance, and extensive morphological characterization was conducted to correlate the thermo-fluid dynamic behavior with the geometric and surface features specific to the manufacturing process. The investigation revealed that reticular configurations are preferable when low pressure losses are required, whereas gyroids are more suitable for high thermal loads. The topology of the structures was shown to be a key factor influencing overall performance, emphasizing the importance of selecting the appropriate structure for each specific application and the significant potential for performance improvements through the development of tailored metamaterials. © 2025 by the authors.

关键词： additive manufacturing cooling annular channel heat transfer laser powder bed fusion metamaterials pressure losses

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MODELING RELIABILITY-BASED PATH-FINDING PROBLEMS WITH MULTIPLE OBJECTIVES FOR DIFFERENT TYPES OF TRAVELERS 25

MODELING RELIABILITY-BASED PATH-FINDING PROBLEMS WITH MULTIP...

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25th International Conference of Hong Kong Society for Transportation Studies: Sustainable Mobility, HKSTS 2021

作者： Tam, Mei Lam Chen, Xiao-Wei Chen, Bi Yu Lam, William H.K. Ma, Wei Wong, S.C. Chow, Andy H.F. Department of Civil and Environmental Engineering The Hong Kong Polytechnic University Hong Kong State Key Laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan University Wuhan China Collaborative Innovation Center of Geospatial Technology Wuhan China Department of Civil Engineering The University of Hong Kong Hong Kong Department of Architecture and Civil Engineering City University of Hong Kong Hong Kong

ISBN: (纸本)9789881581495

This paper investigates reliability-based path-finding problems in a stochastic road network with uncertainties. These uncertainties include travel time uncertainty, vehicles' energy-consumption uncertainty and traffic accident risk. Three route-choice objectives are considered in the path-finding problems, which maximize the travel time reliability (TTR) and the energy-consumption reliability (ECR) and minimize the expected traffic accident risk, to meet the preferences of different types of travelers. The TTR is defined as the probability that a traveler can arrive at a destination within a given travel time budget. The ECR is referred to the probability of completing a journey without running out of a given energy-consumption threshold. A novel heuristic algorithm is proposed to search efficiently the optimal paths by origin and destination based on the selected objective(s). A case study is conducted on the Hong Kong road network to demonstrate the applicability of the proposed algorithm in practice. © 2021 Proceedings of the 25th International Conference of Hong Kong Society for Transportation Studies, HKSTS 2021: Sustainable Mobility. All Rights Reserved.

关键词： Energy utilization

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Review of rules of mixture for effective elastic properties in fibrous and particulate composite materials

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Composite Structures 2025年 367卷

作者： Abdalla, Hassan Mohamed Abdelalim Polytechnic Department of Engineering and Architecture University of Udine Via delle Scienze 206 Udine33100 Italy

Micromechanics based models have been playing an important role in predicting the effective elastic properties of particulate and fibrous linearly elastic composite materials. This paper reviews the simplest most widely-used class of micromechanics models, the so-called rules of mixture, and aims to clarify various misconceptions in their applicability by providing concise derivations from both the mechanics-of-materials and continuum-mechanics approaches. The paper critically reviews the areas in which these analytical models can yield good predictions of effective elastic properties and various historical interventions when properties are underestimated. Besides, it illustrates a generalized framework able to justify their assumptions as lower and upper bounds for elastic properties, though of modest practical application when compared to more refined theories. Eventually, the position of these models with respect to classic assumptions of dilute dispersion is investigated and emphasized with reference to experimental data. © 2025 The Author

关键词： Metamaterials

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INFLUENCE OF RECYCLED MATERIALS ON THE MECHANICAL PROPERTIES OF MACRO SYNTHETIC FIBER-REINFORCED CONCRETE 6th

INFLUENCE OF RECYCLED MATERIALS ON THE MECHANICAL PROPERTIES...

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6th fib International Congress on Concrete Innovation for Sustainability, 2022

作者： Lerna, Michela Caballero-Jorna, Marta Roig-Flores, Marta Foti, Dora Serna, Pedro Department of Civil Engineering Sciences and Architecture Polytechnic University of Bari Bari Italy Instituto de Ciencia y Tecnología del Hormigón Universitat Politècnica de València Valencia Spain Departamento de Ingeniería Mecánica y Construcción Universitat Jaume I Castellón de la Plana Spain

ISBN: (纸本)9782940643158

The use of generated waste is one of the main current objectives worldwide to reduce pollution. Over the last decades, the construction field has worked on incorporating recycled materials inside the concrete matrix. Some of the recycled products that have been incorporated are recycled aggregates and waste fibers. Fiber-reinforced concrete with macro synthetic fibers is a special type of concrete that is increasingly being used in a range of applications, mainly due to its improved post-cracking capacity without corrosion risks. This work aims to compare the response of three macro synthetic fiber reinforced concrete mixes: i) a mix with natural aggregates and commercial polypropylene fibers, ii) a mix with 40% of replacement of coarse natural aggregates by coarse recycled aggregates (from construction and demolition waste (CDW)) and commercial polypropylene fibers, and iii) a mix with 40% or replacement of coarse natural aggregates by coarse recycled aggregates and full replacement of fibers by waste polypropylene fibers. The proportions of the mixes were adapted when including the recycled aggregates due to the different size distribution of the compounds. The properties analyzed are consistency, compression strength, and flexural behavior, following UNE-EN 14651. The results obtained show only slight reductions of compression and flexural strengths at high crack mouth opening displacement (CMOD). These results indicate that recycled aggregates and waste fibers are viable materials to produce macro synthetic fiber-reinforced concretes. © Fédération Internationale du Béton – International Federation for Structural Concrete.

关键词： Polypropylenes

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Strength verification of circular crown arch-shaped fillet welds under static loads

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Structures 2025年 78卷

作者： Giada Frappa Polytechnic Department of Engineering and Architecture University of Udine Via delle Scienze 206 Udine 33100 Italy

Due to the lack of literature studies on the use of analytical methods to determine the stress distribution in curved fillet welds, this study proposes an analytical procedure to determine the stresses in curved fillet welds subjected to an eccentric force coplanar with one of the fillet sides. The procedure is based on the theory of infinitely rigid bodies and the principle of superposition of effects, valid for steel in the elastic range. The procedure is then used to determine the strength of a fillet weld with circular crown arch shape, under different inclination and locations of the external force. Two scenarios are examined: one accounting for the eccentricity of the applied force relative to the centroid of the flipped throat surface, and one without it. Based on the results, the most unfavorable directions of the external force are identified. These findings are then used to determine the optimal location of fillet welds with circular or elliptical crown arch shapes, considering variations in force inclination, force location, and fillet configuration. It is also found that, when the force is applied at the centroid of the flipped throat surface, the magnitude of force resisted by the fillet is independent of its inclination only if the fillet is subtended by a central angle greater than or equal to 180°. Conversely, the fillet cross-section(s) experiencing the most critical stress state is(are) the end section(s) of the fillet. Moreover, a comparison with an established method demonstrates that the proposed approach yields accurate and reliable results. The findings of this study provide valuable insights into the design and strength verification of curved welded joints, aiding engineers in optimizing their design.

关键词： Curved fillet weld Circular tubular profile Stress distribution Effects superposition Structural joints Throat surface

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Incentive Mechanism Design for Promoting High-Quality Green Buildings in China's Multi-Level Governance System

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SSRN 2024年

作者： Hu, Qidan Xiong, Feng Shen, Geoffrey Qiping Liu, Rongsheng Xue, Jin Wu, Hengqin Zhou, Xin MOE Key Laboratory of Deep Earth Science and Engineering College of Architecture and Environment Sichuan University Chengdu610065 China Department of Building and Real Estate The Hong Kong Polytechnic University Kowloon999077 Hong Kong School of Project Management The University of Sydney SydneyNSW2037 Australia

This study proposes optimal policy incentive mechanisms to promote green buildings (GBs) in China’s multi-level governance (MLG) system, addressing challenges of information asymmetry between the central government, local government and developer to ensure high-quality GBs. By developing a dual principal–agent model, incentive mechanisms for both government levels are designed for different scenarios, accounting for non-collusion and collusion situations. Through comparative and numerical analysis, this study finds that incentive mechanism design allows the central government to effectively mitigate the adverse effects of collusion and information asymmetry, ensuring unchanged GB quality, environmental benefits and social welfare while avoiding excessive fiscal burdens. The central government maintains optimal incentive intensity despite collusion, while the local government screens information and incentivises developers through tailored incentive mechanisms, distinguishing between low- and high-cost developers. Incentives drive both high- and low-cost developers to enhance GB quality, with the low-cost developer demonstrating higher green efforts. This study provides valuable insights and practical policy recommendations for promoting high-quality GB development within the MLG context, serving as a reference for promoting GBs under MLG in other countries. © 2024, The Authors. All rights reserved.

关键词： Costs

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A New Field-Oriented Control for Induction Motor Drive Using a Synergetic-Super Twisting Algorithm

A New Field-Oriented Control for Induction Motor Drive Using...

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International Conference on Electronics, Computers and Artificial Intelligence (ECAI)

作者： Dalal Zellouma Habib Benbouhenni Nicu Bizon Youcef Bekakra Department of Electrical Engineering LEVRES Laboratory University of El Oued El Oued Algeria Department of Electrical & Electronics Engineering Faculty of Engineering and Architecture Nisantasi University Istanbul Turkey Faculty of Electronics Communication and Computers University of Pitesti Pitesti Romania ICSI Energy department National Research and Development Institute for Cryogenic and Isotopic Technologies RamnicuValcea Romania Doctoral School Polytechnic University of Bucharest Bucharest Romania

In this work, a new field-oriented control (FOC) is proposed to control the induction motor drives. The FOC method stands out because of its use, simplicity, and fast dynamic speed. However, there are disadvantages to this strategy. One of its disadvantages is that there are ripples in the torque, flux, and levels at present. In addition, the current has a high total harmonic distortion value in comparison to non-linear control. The super-twisting algorithm and synergetic control are strategies of non-linear control, a novel solution is offered to address these issues and enhance the performance and effectiveness of this approach to total harmonic distortion, which is proposed and employed in the conventional FOC strategy to minimize the ripples of current, torque, and total harmonic distortion. To simulate the proposed strategy of IM drive, Matlab software has been used. Comparison results between the suggested control and a traditional FOC technique can illustrate the proposed control greatly improved performance and robustness.

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Design Optimization of Energy-Efficient Residential Buildings in Morocco

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SSRN 2024年

作者： Boumlik, Karim Ahachad, Mohammed Mahdaoui, Mustapha Radoine, Hassan Krarti, Moncef Mohammed VI Polytechnic University School of Architecture Planning and Design Benguerir Morocco MaSEEL FST of Tangier University of Abdelmalek Essaadi Tetouan Morocco Abdelmalek Essaadi University Morocco Civil Environmental and Architectural Engineering Department CB 428 University of Colorado BoulderCO80309 United States

In this paper, an optimization-based analysis approach is presented to cost-effectively improve the energy efficiency of residential buildings in Morocco. The analysis considers the interactive effects between various energy efficiency measures to determine optimal combinations to design high-energy performance as well as net-zero energy residential buildings for six climate zones in Morocco. In particular, the design analysis approach combines a whole-building simulation with the sequential search technique to design residential buildings that minimize life cycle costs and maximize energy savings. The analysis results show that houses in Morocco can be cost-effectively designed to achieve annual energy savings of 51% for zone 1, 53% for zone 2, 60% for zone 3, 67% for zone 4, 54% for zone 5 and 56% for zone 6 compared to the current construction practices considered as reference designs. Moreover, the results indicate that houses can reach net-zero energy building designs with almost the same LCC as the reference design cases for all the climate zones in Morocco. © 2024, The Authors. All rights reserved.

关键词： Zero energy buildings

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Comparative Analysis of Indoor Thermal Environment Characteristics and Occupants’ Adaptability: Insights from Ashrae Rp-884 and the Chinese Thermal Comfort Database

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SSRN 2023年

作者： Yang, Liu Wang, Feixiang Zhao, Shengkai Gao, Siru Yan, Haiyan Sun, Zhen Lian, Zhiwei Duanmu, Lin Zhang, Yufeng Zhou, Xiang Cao, Bin Wang, Zhaojun Zhai, Yongchao State Key Laboratory of Green Building Xi’an University of Architecture and Technology Shaanxi Xi’an710055 China School of Architecture Xi’an University of Architecture and Technology Shaanxi Xi’an710055 China School of Architectural and Artistic Design Henan Polytechnic University Henan Jiaozuo454000 China Department of Architecture School of Design Shanghai Jiao Tong University Shanghai200240 China School of Civil Engineering Dalian University of Technology Liaoning Province Dalian116024 China State Key Laboratory of Subtropical Building Science Department of Architecture South China University of Technology Wushan Guangzhou510640 China School of Mechanical Engineering Tongji University Shanghai200092 China Department of Building Science School of Architecture Tsinghua University Beijing100084 China School of Architecture Harbin Institute of Technology Heilongjiang Province Harbin150090 China

Understanding indoor thermal environment characteristics, Occupants’ adaptability, and making a reasonable assessment based on thermal comfort standards are crucial for achieving energy-efficient and high-quality building environments. Sufficient data from the thermal comfort database serves as an important foundation for analyzing indoor thermal environments. The ASHRAE RP-884 database, a foremost comprehensive global thermal comfort database, has been pivotal in establishing and revising current standards like ISO 7730 and ASHRAE 55. Drawing from the ASHRAE RP-884 and the Chinese Thermal Comfort Database, this study strictly selected 20,074 and 33,775 valid datasets across varying building operation modes, and the analysis reveals significant differences between the indoor thermal environment characteristics in China and RP-884. Moreover, the Chinese population demonstrates heightened adaptability, with 80% acceptable temperature ranges of 23.79 °C to 27.94 °C in cooled buildings, 17.56 °C to 25.79 °C in heated buildings, and 14.60 °C to 30.20 °C in naturally ventilated buildings, presenting a broader range than those in the RP-884 associated countries. Specially, we found the thermal comfort zones defined in ISO 7730 and ASHRAE 55 standards may not fully accommodate the Chinese context. Besides, a thermal adaptation model tailored for China's naturally ventilated buildings was proposed based on Chinese Thermal Comfort Database, with a slope of 0.45, surpassing the 0.31 of ASHRAE and 0.33 of CEN. Lastly, potential reasons for the observed differences were analyzed and discussed. © 2023, The Authors. All rights reserved.

关键词： Thermal comfort

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