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Modelling and Optimization of Clean and Affordable Electricity Solution for Small-Scale Savings and Credit Cooperatives(SACCOs)

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Energy engineering 2023年第4期120卷 791-810页

作者： Xiaomei Lin Samuel Bimenyimana ChenWang Godwin Norense Osarumwensa Asemota Jeanne Paula Ihirwe Aphrodis Nduwamungu Etienne Ntagwirumugara Athanase Gace Changfu Yuan Yaowen Chen Changtai Li Shilpi Bora YiYi Mo Jiyu Lai Mabao Wu Yong Tang Merit M.Huang College of Science and Technology The Open University of FujianFuzhou350013China Intelligence and Automation in Construction Provincial Higher–Educational Engineering Research Centre Huaqiao UniversityXiamen361021China African Centre of Excellence in Energy for Sustainable Development University of RwandaKigali4285Rwanda Morayo College Nairobi999070Kenya Department of Economics and Management Hebei University of TechnologyTianjin300401China College of Science and Technology University of RwandaKigali4285Rwanda Fujian Baichuan Construction Technology Co. Ltd.HuliXiamen361021China Haoqi(Xiamen)Construction Technology Co. Ltd.HaicangXiamen361021China School ofDesign Ajeenkiya D Y PatilUniversityPune412105India College of Civil Engineering Huaqiao UniversityXiamen361021China College of Transportation and Civil Engineering Fujian Agriculture and Forestry UniversityFuzhou350100China Highway Southeast Engineering Co. Ltd.Xiamen361100China Fuzhou Sinotom Information Technology Co. Ltd.Fuzhou350001China

Renewable energy exploitation is among the development strategies set by the government of Rwanda on the roadmap to 2023/2024 universal electricity access and theUnitedNations plans by *** previous studies oncleanenergy technologies inRwandahavemostly focusedonhouseholds’usagebut there are currentlynostudies describing the feasibility of clean energy technologies for financial *** skepticism on renewable energy in Africa was previously reported by some *** realized that most SACCOs(Savings and Credit Co-Operatives)in Rwanda use diesel technology for backup/emergency electricity supply,taking consideration of abundant solar resources in Rwanda,having seen the viability and feasibility studies from other countries of renewable energy for different institutions(financial included);thiswork uses theHOMEREnergy Software and the electricity load profile of a typical SACCO in Rwanda to analyse the affordability and viability of on-site renewable energy generation for SACCO in *** results reveal that a solar PV systemwith storage can be the optimal solution(with levelized cost of electricity(LCOE)of 0.713$/kWh which is cheaper than 0.73$/kWh for diesel technology)for SACCOs located in both off-grid areas and grid-connected areas(with 0.041$/kWh LCOE which is lower than the current electricity tariff in Rwanda).The findings in this work can serve as basic tools/materials for policy drafters in Rwanda on how financial institutions can contribute to climate change mitigation through self-renewable energy exploitation.

关键词： HOMER energy solar energy SACCO in Rwanda climate change mitigation

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construction Research Congress 2022

Construction Research Congress 2022

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construction Research Congress 2022: Project Management and Delivery, Controls, and Design and Materials, CRC 2022

作者： Ahmed, Muaz O. El-Adaway, Islam H. Coatney, Kalyn Dept. of Civil Architectural and Environmental Engineering Missouri Univ. of Science and Technology RollaMO United States Hurst-McCarthy Professor of Construction Engineering and Management Professor of Civil Engineering and Founding Director of Missouri Consortium of Construction Innovation Dept. of Civil Architectural and Environmental Engineering and Dept. of Engineering Management and Systems Engineering Missouri Univ. of Science and Technology RollaMO United States Dept. of Agricultural Economics Mississippi State Univ MississippiMS United States

ISBN: (纸本)9780784483978

The global and national spending on public infrastructure projects continues to increase tremendously. Accordingly, contractors need to adopt efficient bidding strategies to cope with the legal requirement of competitive bidding within the public infrastructure projects. Moreover, contractors usually acquire the services of subcontractors to handle large projects. However, despite the previous research efforts on developing bidding models, there is still a lack of research that tackles the multi-stage construction bidding, where subcontractors submit quotations/bids first and general contractors bid second for the whole project. As such, this paper aims to develop a game-theoretic bidding model for multi-stage construction bidding. To this end, the authors utilized an interrelated methodology comprised of: (1) investigating existing bidding models that are based on a game theory approach;(2) deriving of a bid function for the multi-stage construction bidding following the low bid method where the lowest bidder is the winner;(3) simulating multi-stage bidding environment;and (4) validating the derived bid function and simulation model utilizing data of 808 US public infrastructure projects. Results indicate that the derived bid function gives general contractors a competitive advantage by reducing the occurrence and magnitude of earning negative profits (known as the winner's curse) while winning a reasonable number of projects;and hence, resulting in a higher expected profit. Ultimately, this study adds to the body of knowledge by providing a bidding model for the multi-stage construction bidding that shall aid contractors in dealing with the uncertainties within the associated decision-making process. © 2022 ASCE.

关键词： Contractors

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The application of steel slag aggregate for concrete pavement: Mechanical properties and stability

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Journal of the Chinese Institute of civil and Hydraulic engineering 2022年第8期34卷 739-748页

作者： Vo, Duy-Hai Do, Ngoc-Duy Hwang, Chao-Lung Liao, Min-Chih Lu, Chien-Ming Department of Civil Engineering Danang University of Technology and Education Danang912301 Viet Nam Department of Civil and Construction Engineering National Taiwan University of Science and Technology Taipei10607 Taiwan Department of Civil and Construction Engineering National Taiwan University of Science and Technology Taipei10607 Taiwan

This study aims to evaluate the performance of steel slag aggregate concrete for concrete pavement. Three kinds of Ladle furnace slag (LFS) with different expansion ratios were used as fine aggregate, while two kinds of Rotary kiln slag (RKS) named as Acid (AC) and Alkaline (AK) steel slag were used as coarse aggregate to manufacture the concrete specimens. The mix-proportions were designed using the Densified mixture design algorithm (DMDA) method with various water-to-binder (w/b) ratios of 0.3, 0.4 and 0.5. Compressive strength, splitting tensile strength, ultrasonic pulse velocity (UPV), electrical surface resistivity (ESR), and length change performance under autoclave tests were conducted to evaluate the concrete samples' mechanical properties and dimension stability up to 56 days of curing ages. The findings illustrated that the w/b ratio significantly affected the engineering properties of concrete samples. The LFS-II, with an expansion range of 0.2% ~ 0.4%, presented better mechanical properties than other fine aggregate kinds. AK concrete showed a more excellent engineering property than AC concrete. The LFS-I exhibited good stabilization after autoclaved test, while the higher expansion fine aggregate was not stable under autoclaved analysis. © 2022, Chinese Institute of civil and Hydraulic engineering. All right reserved.

关键词： Tensile strength

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Experimental study on the movement law of overlying rock non-pillar coal overhead mining

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Journal of Mountain Science 2023年第6期20卷 1759-1773页

作者： LI Yong ZHENG Jing WANG Feng-nian MA Xin-gen ZHANG Rui-xue SUN Ying-ying YIN Jian-bin TAO Zhi-gang College of Geoscience and Surveying Engineering China University of Mining and Technology-BeijingBeijing 100083China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology-BeijingBeijing 100083China Shanxi Provincial Transportation Technology Research and Development Co.Ltd. Key Laboratory of Highway Construction and Maintenance Technology in Loess AreaTransportation IndustryTaiyuan 030000China Huaneng Coal Technology Research Co.Ltd. Beijing 10o83China State Key Laboratory for Geo Mechanics and Deep Underground Engineering China University of Mining and Technology-BeijingBeijing 10083China School of Mechanics and Civil Engineering China University of Mining and Technology-BeijingBeijing 100083China

Pillarless coal mining technology is a new practical *** on the compensating mechanical behavior of the Negative Poisson’s Ratio(NPR)anchor cable on the roof,the roadway was successfully retained by the top cutting and pressure relief *** study utilizes the Digital Speckle Monitoring(DIC monitoring),stress-strain monitoring,and infrared thermal imaging systems to conduct physical model experiment of similar materials from the displacement,stress-strain,and temperature fields to investigate in depth the fracture change law of the overlying *** addition,it uses FLAC3D numerical simulation to invert the surface displacement *** results show that the non-pillar overhead mining under the 110 mining method has little influence on the rock crack in the middle of the coal seam,and the crack development area is mainly concentrated in the overlying rock mass of the upward coal *** compensatory mechanical behavior of NPR anchor cable and the dilatation characteristics of rock mass have a good effect of retaining roadway along goaf,and can also reduce surface *** 110 mining method provides a scientific basis for ecological environment protection and the development of other kilometer deep soft rock high ground stress underground projects.

关键词： No pillar mining Overhead mining NPR anchor cable Physical model of similar materials FLAC3D Numerical simulation Motion of overburden

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Agent-based modeling approach for evaluating underground logistics system benefits and long-term development in megacities

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Journal of Management Science and engineering 2022年第2期7卷 266-286页

作者： Wanjie Hu Jianjun Dong Jingfeng Yuan Rui Ren ZHIlong Chen Helan Cheng College of Architecture and Civil Engineering Beijing University of TechnologyBeijing100124China College of Civil Engineering Nanjing Tech UniversityNanjing211800China Department of Construction Management and Real Estate Southeast UniversityNanjing210096China College of Defense Engineering Army Engineering University of PLANanjing210001China Nanjing KENTOP Civil Engineering CO. LTDNanjing210041China

Mobility,pollution,and other barriers against sustainable goods movement are pushing local administrators to seek innovations in urban transportation *** urban underground logistics system(ULS)has been recognized as a prospective alternative to realize large-scale automated freight distribution within and around *** paper proposes an integrated approach combing system dynamics and agent-based modeling to evaluate the long-term development and operating status of a city-wide ULS *** project boundaries regarding underground network expansion,stakeholders’attributes,and social-environmental benefit metrics were structured as eight highly-interacted agent *** decision variables of agents in terms of supply-demand equilibrium,investment plan,pricing-to-market and willingness-to-pay were incorporated into three formulized subsystem *** empirical perspective,the urban territory of Beijing,China,was taken as a case to simulate the development footprints of ULS project under different funding options and market acceptance *** show that ULS has significant competence with respect to service capacity and profitability,while enabling billions of dollars of external cost-saving ***,the comprehensive performance of ULS project regarding economic incomes,benefits,market demand,and construction schedule can reach satisfactory trade-offs through adaptively adjusting the funding policies,incentives and pricing portfolios during project development.

关键词： Underground logistics system Sustainabletransport Project development Cost-and-benefit System dynamics Agent-based modeling

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Some Issues of the Kyiv TV Tower Renovation After the Missile Attack 6th

Some Issues of the Kyiv TV Tower Renovation After the Missil...

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6th International Scientific Conference on Environmental Challenges in civil engineering, ECCE 2024

作者： Shymanovskyi, Oleksandr Baran, Wieslaw V. Shymanovskyi Ukrainian Institute of Steel Construction V. Shymanovskyi St. 2/1 Kyiv02125 Ukraine Faculty of Civil Engineering and Architecture Opole University of Technology Katowicka 48 Opole45-061 Poland

ISBN: (纸本)9783031737756

The paper presents some issues concerning the renovation of the Kyiv TV tower after the missile fire that followed the attack on Ukraine by the Muscovite invaders. It is noted that the 385-m-high Kyiv TV tower was inaugurated on July 30, 1973, and at the time of construction as well as for the next 37 years, it was the highest freestanding welded steel lattice tower in the world, and many new solutions were applied during the design of the tower. It is noted that on March 1, 2022, the Muscovite invaders launched a targeted double missile attack on the TV tower, which, despite some damage, withstood the impact of the blast wave. It is noted that after the attack on the TV tower, an inspection of its technical condition was carried out, which indicated that the joint of the tower metal structures at elevation + 56,000 m, which was directly in the center of the explosion, suffered the most damage. In some other metal structures, only separate holes, cracks, and dents of various sizes were found, which were formed due to the impact of the missile fragments. Design features for new TV tower structures intended to replace the destroyed elements and strengthen partially damaged elements are defined based only on solutions that would not interrupt the existing structural layout and stress state of the tower. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Television towers

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Evaluating dynamic behaviour of a concrete dam using modal analysis

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Materials Today: Proceedings 2023年 93卷 296-301页

作者： Surabhi Saxena Mahesh Patel Civil Engineering (Structural and Construction Engineering) at Dr B.R. Ambedkar National Institute of Technology Jalandhar 144011 India Civil Engineering at Dr B.R. Ambedkar National Institute of Technology Jalandhar 144011 India

Modal Analysis is the most fundamental aspect of the dynamic study of structures. It is used to determine the vibrational characteristics of linear elastic structures. It suggests the natural frequencies and mode shapes, which are essential to understand the dynamic behaviour of that structure. In this study, Shahpurkandi Dam, a concrete gravity dam of height 55.5 m is considered in order to investigate its dynamic properties using the finite element package ‘ANSYS’. Furthermore, structure-acoustic interaction is explicitly modelled, and a case of the full reservoir is taken into account to analyze the modal response of the dam. The first 6 mode shapes are extracted, and the total displacement is recorded through the numerical simulation of the direct solver including the block Lanczos method. This study shows the maximum deformation is recorded for the first fundamental natural frequency, which is 0.0039 mm at the crest of the dam. Henceforth, it is essential to monitor the mode shape and natural frequency of initial modes. The comparison of natural frequency is also demonstrated for full reservoir and empty reservoir cases.

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Experimental investigation on rehabilitation effectiveness of ductile RC beams with various seismic damage levels using dynamic and static-cyclic loading protocols

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Structure and Infrastructure engineering 2024年

作者： Chiu, Chien-Kuo Sung, Hsin-Fang Chen, Po-Chun Department of Civil and Construction Engineering National Taiwan University of Science and Technology Taipei Taiwan Environmental Information and Engineering Department National Defense University Chung Cheng Institute of Technology Taoyuan Taiwan

With respect to the seismic damage of a ductile reinforced concrete (RC) beam in an RC building structure with seismic design, since the functionality of the building must be recovered, the maximum strength and ductility of the member must be restored by repair or retrofit. Therefore, this work focuses on the effectiveness of the selected repair and retrofit methods in rehabilitating a ductile RC beam with a specified damage level. For this purpose, eight RC beam specimens are designed based on the seismic design requirements in ACI 318-19 to investigate their mechanical properties using the test. In the experiment, loading protocol tests of two types - traditional static-cyclic loading protocol and earthquake-then-cyclic loading protocol—are conducted to quantify the effectiveness of rehabilitation of the RC beam specimens with the selected repair or retrofit methods. The repair and retrofit methods include surface treatment, epoxy low-pressure injection, epoxy resin mortar coating, rebar planting and steel plate retrofitting. Finally, the test results related to the development of strength, stiffness and cracking are used to quantify the effectiveness of rehabilitation of the ductile RC beams with various seismic damage levels using the selected repair or retrofit methods. © 2024 Informa UK Limited, trading as Taylor & Francis Group.

关键词： Reinforced concrete

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Study of Soft Rock Anisotropy Based on Three-point Bending Experiments

Study of Soft Rock Anisotropy Based on Three-point Bending E...

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2024 International Conference on Applied Mathematics, Modelling and Statistics Application, AMMSA 2024

作者： Yao, Guoming Li, Weiguo Lu, Yunhui Song, Xinhong Yu, Zhehan Chen, Jiancheng Yu, Wenhai Wu, Yonghong Baoshan Longying Expressway Co. Ltd Yunnan Communications Investment & Construction Group Co. Ltd. Baoshan678099 China State Key Laboratory for GeoMechanics and Deep Underground Engineering China University of Mining & Technology Beijing10083 China Faculty of Civil Engineering and Mechanics Kunming University of Science and Technology Kunming650500 China

Under the influence of its layered structure, soft rock exhibits significant non-homogeneity in its mechanical properties and a certain degree of anisotropy in its fracture characteristics. In this paper, we utilize GDEM-Pdyna to conduct numerical simulations of three-point bending experiments on soft rocks with various layered structures. The research focuses on examining the mechanical properties and anisotropic characteristics of soft rocks subjected to three-point bending tests with different prefabricated fracture angles and layered angles. The experimental results indicate that as the prefabricated crack angle increases, the peak strength required for the failure of the soft rock gradually increases. The load-displacement curves and deformation field maps for soft rocks with horizontal and vertical grain layers under three-point bending loading show a certain degree of consistency. Additionally, with an increase in the angle of the laminae, both the peak load and peak displacement during the loading process gradually decrease, along with a corresponding decrease in fracture toughness. This study provides valuable insights into the mechanical behavior and anisotropic characteristics of soft rocks, contributing to a better understanding of their response under different loading conditions and structural configurations. © Published under licence by IOP Publishing Ltd.

关键词： Anisotropy

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Mechanical and acoustic emission characteristics of anhydrite rock under freeze-thaw cycles

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Journal of Mountain Science 2023年第1期20卷 227-241页

作者： ZHANG Chi JIN Xiao-guang HOU Chao HE Jie School of Civil Engineering Chongqing UniversityChongqing400045China China Railway 14TH Bureau Group Fourth Engineering Corporation Limited Jinan250101China Key Laboratory of New Technology for Construction of Cities in Mountain Area of the Ministry of Education Chongqing UniversityChongqing400045China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing400045China

To study the damage mechanisms of anhydrite rock under freeze-thaw cycles, the physicalmechanical properties and the microcracking activities of anhydrite rock were investigated through mass variation, nuclear magnetic resonance, scanning electron microscope tests, and uniaxial compression combined with acoustic emission(AE) tests. Results show that with the increase of freeze-thaw processes,the mass, uniaxial compression strength, and elastic modulus of the anhydrite specimens decrease while the porosity and plasticity characteristics *** example, after 120 cycles, the uniaxial compression strength and elastic modulus decrease by 46.54% and 60.16%, and the porosity increase by 75%. Combined with the evolution trend of stressstrain curves and the detected events, three stages were labeled to investigate the AE characteristics in freeze-thaw weathered anhydrite rock. It is found that with the increase of freeze-thaw cycles, the proportions of AE counts in stage Ⅰ and stage Ⅱ show a decaying exponential trend. Contrarily, the proportion of AE counts in stage Ⅲ displays an exponential ascending trend. Meanwhile, as the freeze-thaw cycles increase, the low-frequency AE signals increase while the intermediate-frequency AE signals decrease. After 120 cycles, the proportion of low-frequency AE signals increases by 168.95%, and the proportion of intermediate-frequency AE signals reduces by 81.14%. It is concluded that the microtensile cracking events occupy a dominant position during the loading process. With the increase of freeze-thaw cycles, the b value of samples *** 120 cycles, b value decreases by 27.2%, which means that the proportion of cracking events in rocks with small amplitude decreases. Finally, it is proposed that the freeze-thaw damage mechanism of anhydrite is also characterized by the water chemical softening effect.

关键词： Freeze-thaw cycles Anhydrite rock Physical and mechanical properties AE characteristics Damage mechanism

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