检索结果-南通市图书馆

Influence of curing conditions on the shrinkage behavior of three-dimensional printed concrete formwork

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil engineering 2024年第8期18卷 1225-1236页

作者： M.BEKAERT K.van TITTELBOOM G.de SCHUTTER Magnel-Vandepitte Laboratory for structural engineering and building Materials Department of Structural Engineering and Building MaterialsFaculty of Engineering and ArchitectureGhent UniversityGhent 60 B-9052Belgium

The use of three-dimensional(3D)printed concrete as formwork is becoming more widely applied within the ***,the technology is still not optimized and there are many reports of preliminary cracking during the curing of cast *** is believed to result from differential shrinkage between the printed and cast *** cracks(in the printed concrete or at the interface between the infill and printed concrete)form a preferential path for aggressive substances and can reduce the durability of the combined concrete *** ensure the desired service life of the structure,it is important that the differential shrinkage between cast and printed concrete is *** study investigated the effect of curing conditions on the differential shrinkage behavior of 3D and cast *** influence of prewetting of the dry-cured 3D printed formwork was also *** the experimental program,a vibrated and self-compacting concrete were used as cast *** 3D printed formwork was produced and combined with cast concrete to simulate a concrete *** formwork was cured for 1,7,or 28 d exposed to the air(relative humidity:60%or 95%)or submerged in *** length change of the combined elements was observed over 56 d after concrete casting and throughout the thickness of the *** show that increasing the curing period in dry conditions of the printed concrete leads to an expansion of the formwork on the first day after *** expansion leads to a non-uniform strain evolution throughout the curing period of the combined *** concrete formwork stored in wet conditions does not expand after the casting process but tends to show a decreasing linear deformation within the whole elements.

关键词： 3D concrete printing formwork shrinkage curing

Research progress of CO_(2) capture and mineralization based on natural minerals

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1208-1227页

作者： Chenguang Qian Chunquan Li Peng Huang Jialin Liang Xin Zhang Jifa Wang Jianbing Wang Zhiming Sun School of Chemical and Environmental engineering China University of Mining and Technology(Beijing)Beijing 100083China Shanghai construction building Material Technology Group Shanghai 200080China

Natural minerals,such as kaolinite,halloysite,montmorillonite,attapulgite,bentonite,sepiolite,forsterite,and wollastonite,have considerable potential for use in CO_(2) capture and mineralization due to their abundant reserves,low cost,excellent mechanical prop-erties,and chemical *** the past decades,various methods,such as those involving heat,acid,alkali,organic amine,amino sil-ane,and ionic liquid,have been employed to enhance the CO_(2) capture performance of natural minerals to attain high specific surface area,a large number of pore structures,and rich active *** research on CO_(2) capture by natural minerals will focus on the full utiliza-tion of the properties of natural minerals,adoption of suitable modification methods,and preparation of composite materials with high specific surface area and rich active *** addition,we provide a summary of the principle and technical route of direct and indirect mineralization of CO_(2) by natural *** process uses minerals with high calcium and magnesium contents,such as forsterite(Mg_(2)SiO_(4)),serpentine[Mg_(3)Si_(2)O(OH)_(4)],and wollastonite(CaSiO_(3)).The research status of indirect mineralization of CO_(2) using hydro-chloric acid,acetic acid,molten salt,and ammonium salt as media is also introduced in *** recovery of additives and high-value-added products during the mineralization process to increase economic benefits is another focus of future research on CO_(2) mineralization by natural minerals.

关键词： natural mineral carbon dioxide capture modification composite material carbon dioxide mineralization

Adhesion performance of alkali-activated material for 3-dimensional printing of tunnel linings at different temperatures

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil engineering 2024年第1期18卷 66-79页

作者： Yaxin TAO Xiaodi DAI Geert de SCHUTTER Kim Van TITTELBOOM department of Structural engineering and building Materials Ghent UniversityGhent 9052Belgium

Robotic-based technologies such as automated spraying or extrusion-based 3-dimensional(3D)concrete printing can be used to build tunnel linings,aiming at reducing labor and mitigating the associated safety issues,especially in the high-geothermal ***-based 3D concrete printing(3DCP)has additional advantages over automated sprayings,such as improved surface quality and no ***,the effect of different temperatures on the adhesion performance of 3D-printed materials for tunnel linings has not been *** study developed several alkali-activated slag mixtures with different activator modulus ratios to avoid the excessive use of Portland cement and enhance sustainability of 3D printable *** thermal responses of the mixtures at different temperatures of 20 and 40℃ were *** adhesion strength of the alkali-activated material was evaluated for both early and later ***,the structural evolution of the material exposed to different temperatures was *** was followed by microstructure *** indicate that elevated temperatures accelerate material reactions,resulting in improved early-age adhesion ***,higher temperatures contribute to the development of a denser microstructure and enhanced mechanical strength in the hardened stage,particularly in mixtures with higher silicate content.

关键词： alkali-activated material 3DCP tunnel lining high-geothermal environment adhesion

Simplified seismic scenario analysis of existing masonry buildings accounting for local site effects

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil engineering 2024年第2期18卷 309-318页

作者： Ayşe E.ÖZSOYÖZBAY Işıl SANRI KARAPINAR Zehra N.KUTLU İsmail E.KILIÇ department of Civil engineering Maltepe UniversityIstanbul 34857Turkey School of engineering and construction Oryx Universal CollegeDoha 12253Qatar

This study discusses the effects of local sites and hazard amplification on the seismic vulnerability assessment of existing masonry *** this context,a rapid seismic evaluation procedure was implemented on an old masonry building stock in the historical center Galata,located inİstanbul,to determine the seismic risk priority of the built *** scenarios were generated for all soil classes,different moment magnitudes,and source-to-site distances to obtain more accurate results for the seismic vulnerability assessment of the studied building ***,damage distributions estimated under nine different scenarios with/without site effects were compared and illustrated in maps to discuss changes in vulnerability owing to amplification *** this study,by re-examining the rapid seismic evaluation procedure by including geo-hazard-based assessment,the importance of site effects on the vulnerability and risk assessment of built heritage was *** proposed framework integrating field data and local site effects is believed to advance the current applications for vulnerability assessment of masonry buildings and provide an improvement in the application of rapid seismic assessment procedures with more reliable results.

关键词： masonry buildings seismic vulnerability assessment cultural heritage local site effect

Assessing the energy saving potential of using adaptive setpoint temperatures:The case study of a regional adaptive comfort model for Brazil in both the present and the future

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

building Simulation 2024年第3期17卷 459-482页

作者： Daniel Sánchez-García David Bienvenido-Huertas Carlos Rubio-Bellido Ricardo Forgiarini Rupp department of Electrical engineering University Carlos III of MadridMadridSpain department of building Simulation ZEROCEM SLSevilleSpain department of building constructions University of GranadaGranadaSpain department of building constructions II University of SevilleSevilleSpain Section of Design for Sustainability Department of Civil and Mechanical EngineeringTechnical University of DenmarkKgs.LyngbyDenmark

It has been found in recent years that using setpoint temperatures based on adaptive thermal comfort models is a successful method of energy *** studies using adaptive setpoint temperatures incorporate international models from ASHRAE Standard 55 and *** study,however,has instead considered a regional Brazilian adaptive comfort *** study investigates the energy demand arising from the use of a local Brazilian comfort model in order to assess the energy implications from the use of the worldwide ASHRAE Standard 55 adaptive model and various fixed setpoint *** of Brazil’s climate zones,full air-conditioning,mixed-mode building operating modes,present-day climate change scenarios,and future scenarios—specifically Representative Concentration Pathways(RCP)2.6,4.5,and 8.5 for the years 2050 and 2100—have all been taken into account in building energy *** use of adaptive setpoint temperatures based on the Brazilian local model considering mixed-mode has been found to significantly reduce energy consumption when compared to static setpoint temperatures(average energy-saving values ranging from 52%to 58%)and the ASHRAE 55 adaptive model(average values ranging from 15%to 21%).Considering climate change and the mixed-mode Brazilian model,the overall energy demand for the three groups of climatic zones(annual average outdoor temperatures≤21℃,>21 and≤25℃and>25℃)ranged between 2%decrease and 5%increase,4%and 27%increase,and 13%and 45%increase,*** is concluded as a consequence that setting setpoint temperatures based on the Brazilian local adaptive comfort model is a very efficient energy-saving method.

关键词： adaptive thermal comfort building energy simulation energy efficiency climate change adaptive setpoint temperatures local comfort mode

On the calibration of a shear stress criterion for rock joints to represent the full stress-strain profile

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical engineering 2024年第2期16卷 379-392页

作者： Akram Deiminiat Jonathan D.Aubertin Yannic Ethier department of construction engineering École de Technologie Supérieure(ÉTS)MontréalCanada

Conventional numerical solutions developed to describe the geomechanical behavior of rock interfaces subjected to differential load emphasize peak and residual shear *** detailed analysis of preand post-peak shear stress-displacement behavior is central to various time-dependent and dynamic rock mechanic problems such as rockbursts and structural instabilities in highly stressed *** complete stress-displacement surface(CSDS)model was developed to describe analytically the pre-and post-peak behavior of rock interfaces under differential *** formulations of the CSDS model required extensive curve-fitting iterations which limited its practical applicability and transparent integration into engineering *** present work proposes modifications to the CSDS model aimed at developing a comprehensive and modern calibration protocol to describe the complete shear stressdisplacement behavior of rock interfaces under differential *** proposed update to the CSDS model incorporates the concept of mobilized shear strength to enhance the post-peak ***’s concepts of joint roughness coefficient(JRC)and joint compressive strength(JCS)are incorporated to facilitate empirical estimations for peak shear stress and normal closure ***/uniaxial compression test and direct shear test results are used to validate the updated model and exemplify the proposed calibration *** results illustrate that the revised model successfully predicts the post-peak and complete axial stressestrain and shear stressedisplacement curves for rock joints.

关键词： Full shear profile Post-peak shear behavior Rock joint Joint roughness coefficient(JRC) Axial stress-strain curve

Public perception of connected and automated vehicles:Benefits,concerns,and barriers from an Australian perspective

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Intelligent and Connected Vehicles

Journal of Intelligent and Connected Vehicles 2024年第2期7卷 108-128页

作者： Ali Matin Hussein Dia department of Civil and construction engineering Swinburne University of TechnologyMelbourne 3122Australia

This study investigates the attitudes and concerns of the Australian public toward connected and autonomous vehicles(CAVs),and the factors influencing their willingness to adopt this *** a comprehensive survey,a diverse group of respondents provided valuable insights toward various CAV scenarios such as riding in a vehicle with no driver,self-driving public transport,self-driving taxis,and heavy vehicles without *** results highlight the significant impact of safety concerns about automated vehicles on individuals’attitudes across all *** levels of concern were associated with more negative attitudes,and a strong correlation between concerns and opposition underlines the necessity of addressing these apprehensions to build public trust and promote CAV ***,nearly 70%of respondents felt uncomfortable driving next to a CAV,but they displayed more confidence in adopting automated public transport in the near ***,around 40%of participants indicated a strong willingness to purchase a CAV,primarily driven by the desire to reduce their carbon footprint and safety ***,respondents with health conditions or disability exhibited heightened interest(almost double those without health conditions)in CAV *** differences emerged in attitudes and preferences toward CAVs,with women expressing a greater level of concern and perceiving higher barriers to CAV *** emphasizes the importance of employing targeted approaches to address the specific concerns of different *** study also underscores the role of trust in technology as a significant barrier to CAV deployment,ranking high among respondents’*** overcome these challenges and facilitate successful CAV deployment,various strategies are suggested,including live demonstrations,dedicated routes for automated public transport,adoption incentives,and addressing liability *** findings from this st

关键词： connected and automated vehicles(CAVs) autonomous vehicles public acceptance stakeholder consultations road safety

Topographic seismic effects and avalanche hazard:A case study of Mount Siella(L’Aquila,Central Italy)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第2期21卷 662-675页

作者： Ferdinando TOTANI department of Civil construction-Architecture and Environmental engineering University of L’AquilaL'Aquila 67100Italy

In mountainous areas,snow avalanches could be triggered by the shaking produced by *** forces induced by the earthquake can cause an irregular increase of shear strength load down the slope,for the presence of complex surface and buried *** irregularities generate maximum effects of waves amplification linked to wavelengths comparable to the horizontal dimension of the topographic *** this reason,the selected time-histories represent an appropriate input for the two-dimensional numerical response analyses when a dynamic phenomenon produce the resonant motion of a whole *** represents an important earthquake-induced hazard in snow-covered mountain areas with high probability of seismic *** valleys are located in regions with scare ground motion data and investments on infrastructures are not always accompanied by adequate protection against earthquake-induced *** paper points out a simple deterministic approach for selecting a set of real accelerograms applied to a real case of Siella Mountain(Central Italy)where a large avalanche destroying a tourist facility of Rigopiano resort on 18 January *** selected time histories were used as input for the two-dimensional numerical model of the subsoil to evaluate the topographic seismic amplification in ridge and compare it with the results of other *** methods suggest that morphology-related inertial effects should be considered as an overload action on snow layers when controlling multi-hazard studies and spatial planning.

关键词： Real accelerograms selection Deterministic approach Topographic amplification Avalanche induced by earthquake 2D seismic response.

Sustainable ammonia synthesis:An in-depth review of non-thermal plasma technologies

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第9期96卷 1-38页

作者： Vahid Shahed Gharahshiran Ying Zheng department of Chemical and Biochemical engineering Thompson Engineering BuildingWestern UniversityLondonON N6A 5B9Canada

Ammonia serves both as a widely used fertilizer and environmentally friendly energy source due to its high energy density,rich hydrogen content,and emissions-free ***,it offers convenient transportation and storage as a hydrogen *** dominant method used for large-scale ammonia production is the Haber-Bosch process,which requires high temperatures and pressures and is ***,non-thermal plasma offers an eco-friendly alternative for ammonia synthesis,gaining significant *** enables ammonia production at lower temperatures and pressures using plasma *** review provides insights into the catalyst and reactor developments,which are pivotal for promoting ammonia efficiency and addressing existing *** first,the reaction kinetics and mechanisms are introduced to gain a comprehensive understanding of the reaction pathways involved in plasma-assisted ammonia ***,the enhancement of ammonia synthesis efficiency is discussed by developing and optimizing plasma reactors and effective *** effect of other feeding sources,such as water and methane,instead of hydrogen is also ***,the challenges and possible solutions are outlined to facilitate energy-saving and enhance ammonia efficiency in the future.

关键词： Nitrogen fixation Ammonia synthesis NH_(3) Non-thermal plasma Ni Ru catalyst