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Influence of rice husk ash and hybrid fiber on engineering properties of densified high-performance fiber-reinforced concrete

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Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 2023年第11期237卷 2845-2857页

作者： Vo, Duy-Hai Nguyen, Minh-Hieu Nguyen, May Huu Hwang, Chao-Lung Huynh, Trong-Phuoc The University of Danang University of Technology and Education Danang Viet Nam Vinh Long Department of Construction Vinh Long Viet Nam Civil and Environmental Engineering Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima Japan Department of Bridge and Tunnel Faculty of Civil Engineering University of Transport Technology Hanoi Viet Nam Taiwan Building Technology Center National Taiwan University of Science and Technology Taipei Taiwan Faculty of Civil Engineering College of Engineering Can Tho University Can Tho Viet Nam

Conventional concrete significantly affects the environment due to high CO2 emission into the atmosphere during the production process. In order to improve concrete performance and arrest the incidence of global warming, the use of additive materials for cement replacement has been promoted worldwide. This study was designed to investigate the mechanical properties of high-performance fiber-reinforced concrete (HFRC) produced using rice husk ash (RHA) and hybrid fiber (HF) in accordance with the densified mixture design algorithm (DMDA) mix design method. Samples were produced using RHA as a direct replacement for cement at 10%, 20%, and 30%. HF, comprising steel and polypropylene fibers, was added (by volume) to the 20% RHA group mixture to improve the HFRC sample properties. Based on the experimental results, higher RHA contents had a generally negative effect on the fresh properties of the HFRC mixtures. Compressive strength values ranged from 53 to 72 MPa with various RHA and HF content. RHA replacement levels up to 20% had an insignificant effect on the strength development and dynamic modulus of the HFRC samples. However, the addition of HF improved splitting tensile strength, flexural strength, and dynamic modulus remarkably at all curing ages. Furthermore, the 91-day drying shrinkage was in the ranges of 0.032%–0.039% and 0.023%–0.034% using different RHA and HF levels, respectively. Increasing both RHA and HF contents significantly reduced drying shrinkage in the samples. Multivariable regression was also performed, clarifying that all tested results were consistent and had good correlations. The results of this study also provide a potentially effective use for abundantly available industrial waste products such as fly ash (FA) and RHA to promote the production of greener and more sustainable concrete. © IMechE 2023.

关键词： Bending strength

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CorrA: Leveraging Large Language Models for Dynamic Obstacle Avoidance of Autonomous Vehicles

arXiv

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arXiv 2025年

作者： Wang, Shanting Typaldos, Panagiotis Malikopoulos, Andreas A. System Engineering Program Cornell University IthacaNY United States School of Civil and Environmental Engineering Cornell University IthacaNY United States School of Civil and Environmental Engineering The System Engineering Program Cornell University IthacaNY United States

In this paper, we present Corridor-Agent (CorrA), a framework that integrates large language models (LLMs) with model predictive control (MPC) to address the challenges of dynamic obstacle avoidance in autonomous vehicles. Our approach leverages LLM reasoning ability to generate appropriate parameters for sigmoid-based boundary functions that define safe corridors around obstacles, effectively reducing the state-space of the controlled vehicle. The proposed framework adjusts these boundaries dynamically based on real-time vehicle data that guarantees collision-free trajectories while also ensuring both computational efficiency and trajectory optimality. The problem is formulated as an optimal control problem and solved with differential dynamic programming (DDP) for constrained optimization, and the proposed approach is embedded within an MPC framework. Extensive simulation and real-world experiments demonstrate that the proposed framework achieves superior performance in maintaining safety and efficiency in complex, dynamic environments compared to a baseline MPC approach. © 2025, CC0.

关键词： Constrained optimization

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Developing a Waste Management Strategy for Reducing Jakarta's Greenhouse Gas Emissions

SSRN

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SSRN 2024年

作者： Kristanto, Gabriel Andari Dahlan, Astryd Viandila Sekarsari, Nindi Environmental Engineering Study Program Civil Engineering Departement Engineering Faculty Universitas Indonesia Depok16424 Indonesia

Increasing amount of waste poses substantial environmental issues because poor waste management emits higher greenhouse gas (GHG, contributing to global warming and climate change. As Indonesia's most populous city, Jakarta faces challenges related to waste management. The city generates significant waste daily, with limited resources and funding to manage it *** study aims to analyze GHG emissions from Jakarta's waste sector and design management scenarios to optimize GHG emission reductions. The research examines local factors to determine the most effective scenario for Jakarta from three proposed waste management designs. The findings may serve as a basis for policymaking that promotes low-carbon and climate-resilient regional development. The study demonstrates that integrated waste management can significantly reduce GHG emissions compared to current practices in Jakarta. However, challenges related to policy and legal frameworks, stakeholder engagement, waste facility technologies, and financial resources must be addressed to achieve these reductions. © 2024, The Authors. All rights reserved.

关键词： Greenhouse gas emissions

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Integration of Small Unmanned Aircraft Systems and Deep Learning for Efficient Airfield Pavement Crack Detection and Assessment

Integration of Small Unmanned Aircraft Systems and Deep Lear...

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International Conference on Transportation and Development 2024: Transportation Safety and Emerging Technologies, ICTD 2024

作者： All Sourav, Md Abdullah Ceylan, Halil Kim, Sunghwan Brynick, Matthew Dept. of Civil Construction and Environmental Engineering Iowa State Univ. AmesIA United States Dept. of Civil Construction and Environmental Engineering and Program for Sustainable Pavement Engineering and Research Iowa State Univ. AmesIA United States Program for Sustainable Pavement Engineering and Research Institute for Transportation Iowa State Univ. AmesIA United States Federal Aviation Administration Airport Pavement R&D Section William J. Hughes Technical Center NJ United States

ISBN: (纸本)9780784485514

Airfield pavement inspection and maintenance are critical aspects of aviation infrastructure, representing a substantial portion of life-cycle costs. Longitudinal, transverse, and diagonal (LTD) cracks;corner breaks;shattered slabs in Portland cement concrete (PCC) pavement;and longitudinal and transverse (L&T) cracks of asphalt concrete (AC) pavement consist of most of the airfield pavement distresses. Traditional airfield pavement inspection methods are manual, time-consuming, laborious, and reliant on the inspector’s experience, leading to increased expenses and safety risks. This research explores the potential to automatically identify those distresses in red-green-blue images using four variants of deep learning (DL) model YOLOv8, ranging from nano to large. YOLOv8 is a widely used off-the-shelf DL object detection model that allows rapid training and easy execution. A DL training dataset of 5,273 small uncrewed aircraft systems (sUAS) collected images was developed. The transfer learning technique was used, and the dataset passed through each model 100 times for adequate training. The model exhibits mean average precision values exceeding 0.65, with varying processing times. Such accuracy showed that crack-related distress detection using DL models could enhance airfield pavement inspection efficiency. © ASCE.

关键词： Drones

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Advancing Understanding of Urgent Gaps and Needs in Atmospheric Science Key Insights from the Climate, Weather, and Water Forum

Advancing Understanding of Urgent Gaps and Needs in Atmosphe...

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作者： Zhang, Lujia Song, Yurong Cheng, Tat Fan Lu, Mengqian Interdisciplinary Program Office Hong Kong University of Science and Technology Hong Kong Department of Civil and Environmental Engineering Hong Kong University of Science and Technology Hong Kong

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Comprehensive Geometric Modeling of the Sibayak Geothermal Field

Comprehensive Geometric Modeling of the Sibayak Geothermal F...

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2024 International Conference on Applied Sciences and Material Applications, ICASMA 2024

作者： Qarinur, M. Silitonga, E.M.R. Alvan, S. Ogata, S. Kinoshita, N. Yasuhara, H. Civil Engineering Study Program Universitas Negeri Medan Medan20221 Indonesia Construction Management Study Program Universitas Negeri Medan Medan20221 Indonesia Division of Global Architecture Graduate School of Engineering Osaka University Osaka565-0871 Japan Department of Civil and Environmental Engineering Ehime University Matsuyama790-8577 Japan Department of Urban Management Kyoto University Kyoto615-8540 Japan

Geothermal reservoirs are significant sources of renewable energy. Accurate geometric modeling of these reservoirs is essential for understanding the distribution of heat and fluid dynamics within them. This study aims to develop a geometric model of the Sibayak geothermal field using borehole data. Borehole data provide detailed geological information, which is crucial for constructing a realistic geometric model. The methodology of this research involves several key steps: the collection of borehole data from the Sibayak geothermal field, the construction of a 3D geometric model of the reservoir using COMSOL Multiphysics based on the borehole data, and the validation of the model through comparison with field data and previous research findings. The results indicate that the developed geometric model successfully identifies zones with high geothermal potential and provides an accurate depiction of the reservoir's boundaries and characteristics. Modeling the geometry of geothermal reservoirs using borehole data offers profound insights into the internal dynamics of the reservoir and can serve as a valuable tool for planning and optimizing geothermal energy exploitation. © 2024 Institute of Physics Publishing. All rights reserved.

关键词： Geothermal fields

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Lactate-mediated medium-chain fatty acid production from expired dairy and beverage waste

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environmental Science and Ecotechnology 2024年第5期21卷 278-286页

作者： Bin Bian Wenxiang Zhang Najiaowa Yu Wei Yang Jiajie Xu Bruce E.Logan Pascal E.Saikaly Water Desalination and Reuse Center(WDRC) King Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Kingdom of Saudi Arabia Environmental Science and Engineering Program Biological and Environmental Science and Engineering(BESE)DivisionKing Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Kingdom of Saudi Arabia Department of Civil and Environmental Engineering The Pennsylvania State UniversityUniversity ParkPA16802USA Research Centre of Ecology&Environment for Coastal Area and Deep Sea Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)Guangzhou511458China School of Marine Science Ningbo UniversityNingbo315211China

Fruits,vegetables,and dairy products are typically the primary sources of household food ***,anaerobic digestion is the most used bioprocess for the treatment of food waste with concomitant generation of ***,to achieve a circular carbon economy,the organics in food waste should be converted to new chemicals with higher value than *** we demonstrate the feasibility of medium-chain carboxylic acid(MCCA)production from expired dairy and beverage waste via a chain elongation platform mediated by *** a two-stage fermentation process,the first stage with optimized operational conditions,including varying temperatures and organic loading rates,transformed expired dairy and beverage waste into lactate at a concentration higher than 900 mM C at 43℃.This lactate was then used to produce>500 mM C caproate and>300 mM C butyrate via microbial chain ***,lactate-producing microbes such as Lactobacillus and Lacticaseibacillus were regulated by temperature and could be highly enriched under mesophilic conditions in the firststage *** the second-stage chain elongation reactor,the dominating microbes were primarily from the genera Megasphaera and Caproiciproducens,shaped by varying feed and inoculum *** network analysis revealed positive correlations among species from the genera Caproiciproducens,Ruminococcus,and CAG-352,as well as Megasphaera,Bacteroides,and Solobacterium,indicating strong microbial interactions that enhance caproate *** findings suggest that producing MCCAs from expired dairy and beverage waste via lactate-mediated chain elongation is a viable method for sustainable waste management and could serve as a chemical production platform in the context of building a circular bioeconomy.

关键词： Microbial chain elongation Medium chain carboxylic acids Food waste Fermentation

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Co-Al layered double oxide activated carbon composite for eliminating lead ions from water

Co-Al layered double oxide activated carbon composite for el...

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2023 Sharjah International Conference on Physics of Advanced Materials, SICPAM 2023

作者： Abushawish, Alaa Chatla, Anjaneyulu Almanassra, Ismail W Shanableh, Abdallah Atieh, Muataz Ali Research Institute of Sciences & Engineering University of Sharjah Sharjah27272 United Arab Emirates Department of Civil and Environmental Engineering University of Sharjah Sharjah27272 United Arab Emirates Chemical and Water Desalination Engineering Program College of Engineering University of Sharjah Sharjah27272 United Arab Emirates

In the current study, preparation of cobalt-aluminum layered double oxide doped activated carbon (Co-Al LDO/AC) was achieved by the co-precipitation technique and utilized for the remediation of lead (Pb2+) from water. Various methods were employed to examine the properties of the composite material, including BET, XRD, FTIR, SEM, and EDS analysis. The material characterization outcomes indicated that the LDO structure was successfully incorporated into the AC matrices with a surface area of 189.4 m2/g. The influence of adsorption parameters including Co-Al LDO/AC dosage, period of contact, initial Pb2+ loading, and initial solution pH were investigated. Moreover, the isotherm and kinetic models were investigated to provide a deeper understanding of the elimination mechanism of Pb2+ ions. The adsorption results illustrated that pH has a substantial influence on Pb2+ removal with a highest removal effectiveness at pH = 6 and a fast adsorption rate within 7 h. The kinetic data were well aligned with the pseudo-second-order model while the isotherm data obeyed the Sips model (R2>0.966). The highest adsorption uptake, estimated by the Sips model was 25.09 mg/g. Considering the modeling and characterization of the spent Co-Al LDO/AC, a chemical interaction process was involved in the elimination process and mainly controlled by ion exchange, electrostatic interactions, and surface complexation mechanisms. Accordingly, the Co-Al LDO/AC could have great potential as a promising hybrid for the purification of toxic Pb2+ ions from contaminated water streams. © Published under licence by IOP Publishing Ltd.

关键词： Ions

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Leaching behavior of sustainable concrete made with coal ash wastes as replacement of cement and sand

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environmental Science and Pollution Research 2024年第52期31卷 61437-61450页

作者： Rafieizonooz, Mahdi Kim, Jang-Ho Jay Khankhaje, Elnaz Rezania, Shahabaldin School of Civil and Environmental Engineering Yonsei University Yonsei-Ro 50 Seodaemun-Gu Seoul03722 Korea Republic of Architectural Engineering Program School of Architecture Seoul National University of Science and Technology 232 Gongneung-Ro Gongneung-Dong Nowon-Gu Seoul01811 Korea Republic of Department of Environment and Energy Sejong University Seoul05006 Korea Republic of

The coal-fired power plant fly ash (FA) and bottom ash (BA) are gradually used as alternative materials in the concrete. However, knowledge of the leaching characteristics of using both incinerator ashes in concrete production is lacking. This work aimed to evaluate the leaching behavior of the FA and BA used in concrete production by employing batch and tank leaching tests. The outcomes of both leaching tests showed that there was no considerable leaching of any trace elements to the environment, and it remains much lower than standard limitations for utilization as construction materials. The results of cumulative mass discharge showed that the slope of flux time for all elements was less than 0.4 and because of that, primary surface wash-off was the main discharge process of all the heavy metals. Strength test results revealed that there was not much difference between coal ash concrete (CAC) and the control mix at the initial age of curing time. Despite that, at a long period of curing time (180 days), the compressive strength of CAC containing 20% FA as cement replacement and 100% BA as fine aggregate replacement increased by 76% due to the pozzolanic reaction of BA and FA in comparison to the normal concrete, while, due to the high porosity of BA, the workability of CAC decreased by 50%. The outcomes of the current work revealed that the combined use of FA and BA can be counted as a promising alternative in the production of sustainable concrete for structural applications toward sustainable development. Graphical abstract: (Figure presented.) © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.

关键词： Trace elements

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Assessment of the Impact of COVID-19 Lockdown on the Spatio-Temporal Distribution of PM2.5 in Thailand 1

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8th Asia Conference on Environment and Sustainable Development, ACESD 2023

作者： Simatupang, Cathleen Ariella Piyaviriyakul, Pitchaya Pongkiatkul, Prapat Strezov, Vladimir Boontanon, Narin Jindal, Ranjna Boontanon, Suwanna Kitpati Graduate Program in Environmental and Water Resources Engineering Department of Civil and Environmental Engineering Faculty of Engineering Mahidol University Nakhon Pathom73170 Thailand School of Natural Sciences Faculty of Science and Engineering Macquarie University SydneyNSW2109 Australia Department of Environmental Engineering King Mongkut’s University of Technology Thonburi 10800 Bangkok Thailand Faculty of Environment and Resource Studies Mahidol University Nakhon Pathom73170 Thailand Environmental Engineering and Management Program Department of Energy Environment and Climate Change School of Environment and Resources Development Asian Institute of Technology 12120 Pathumthani Thailand Graduate School of Global Environmental Studies Kyoto University 606-8501 Yoshida Sakyo-Ku Kyoto Japan

ISBN: (数字)9789819733200

ISBN: (纸本)9789819733194

During COVID-19 pandemic several countries have implemented quarantines in response to the virus’ spread, which was considered an emergency. Thailand was under a state of emergency from January to December 2020, which has had an impact on the state of environment. Based on real-time data from the Pollution Control Department, the impact of COVID-19 lockdown on PM2.5 pollution in Thailand was examined. Inverse Distance Weighted interpolation was used to generate a more accurate visual representation of the PM2.5 pollution through a spatial distribution of atmospheric pollutants across the provinces of Thailand. PM2.5 levels in all considered areas reduced considerably between 2017 and 2020, with the most significant decrease occurring during the lockdown period of April-July in 2020. As the pre-COVID-19 period occurred during late winter in Thailand, the monthly average PM2.5 concentrations in all selected provinces were gradually increased from December 2019 to March 2020. During the lockdown period, the concentration of PM2.5 was reduced in Pathum Thani (48.9%), Samut Sakhon (35.6%) Samut Prakarn (33.6%), and Bangkok (31.7%) The spatial–temporal distribution of the PM2.5 levels in Samut Sakhon and Samut Prakarn provinces were analyzed for October 2020, during the new normal period. The results showed a significant decrease in concentration of up to 31% compared to previous years where industrial operations were situated. This study showed that the government enforced lockdown during COVID-19 pandemic was beneficial in understanding the impact of reduced human activities on anthropogenic air pollutants’ concentrations. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： COVID-19

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