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Mechanism and control of the long-term performance evolution of structures

Zhiqiang DONG, Gang WU, Hong ZHU, Haitao WANG, Yihua ZENG

《结构与土木工程前沿（英文）》 2020年 第14卷 第5期   页码 1039-1048 doi: 10.1007/s11709-020-0667-7

摘要： It is well known that structural properties degrade under long-term environmental exposure and loading and that the degradation rate is controlled by inherent physical and chemical degradation mechanisms. The elucidation of the degradation mechanisms and the realization of effective long-term performance degradation control have been a research frontier in the field of civil engineering in recent years. Currently, the major topics that concern this research frontier include revealing the physical and chemical mechanisms of structural performance evolution under long-term environmental exposure and loading and developing structural performance degradation control technologies based on fiber-reinforced materials, for example, fiber-reinforced polymers (FRPs) and fabric-reinforced cementitious matrix (FRCM). In addition, there are novel structural performance control technologies, such as using a shape memory alloy (SMA) and self-healing concrete. This paper presents a brief state-of-the-art review of this topic, and it is expected to provide a reference for subsequent research.

关键词： degradation mechanism     performance evaluation strengthening     FRP     FRCM    

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Enhanced 4-chlorophenol biodegradation by integrating FeO nanoparticles into an anaerobic reactor: Long-termperformance and underlying mechanism

《环境科学与工程前沿（英文）》 2022年 第16卷 第8期 doi: 10.1007/s11783-022-1519-6

摘要：

• 4-chlorophenol biodegradation could be enhanced in Fe2O3 coupled anaerobic system.

关键词： Dechlorination     Fe2O3 nanoparticles     Electron transfer     Microbial community    

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Long-Term Performance and Microstructural Characterization of Dam Concrete in the Three Gorges Project

Chen Lyu,Cheng Yu,Chao Lu,Li Pan,Wenwei Li,Jiaping Liu,

《工程（英文）》 doi: 10.1016/j.eng.2023.04.017

摘要： This study investigates the long-term performance of laboratory dam concrete in different curing environments over ten years and the microstructure of 17-year-old laboratory concrete and actual concrete cores drilled from the Three Gorges Dam. The mechanical properties of the laboratory dam concrete, whether cured in natural or standard environments, continued to improve over time. Furthermore, the laboratory dam concrete exhibited good resistance to diffusion and a refined microstructure after 17 years. However, curing and long-term exposure to the local natural environment reduced the frost resistance. Microstructural analyses of the laboratory concrete samples demonstrated that moderate-heat cement and fine fly ash (FA) particles were almost fully hydrated to form compact microstructures consisting of large quantities of homogeneous C-(A)-S-H gels and a few crystals. No obvious interfacial transition zones were observed in the microstructure owing to the long-term pozzolanic reaction. This dense and homogenous microstructure was the crucial reason for the excellent long-term performance of the dam concrete. A high FA volume also played a significant role in the microstructural densification and performance growth of dam concrete at a later age. The concrete drilled from the dam surface exhibited a loose microstructure with higher microporosity, indicating that concrete directly exposed to the actual service environment suffered degradation caused by water and wind attacks. In this study, both macro performance and microstructural analyses revealed that the application of moderate-heat cement and FA resulted in a dense and homogenous microstructure, which ensured the excellent long-term performance of concrete from the Three Gorges Dam after 17 years. Long-term exposure to an actual service environment may lead to microstructural degradation of the concrete surface. Therefore, the retained long-term dam concrete samples need to be further researched to better understand its microstructural evolution and development of its properties.

关键词： Three Gorges Dam     Long-term performance     Microstructural analysis     Moderate-heat cement     Fly ash    

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Stabilization-based soil remediation should consider long-term challenges

Zhengtao Shen, Zhen Li, Daniel S. Alessi

《环境科学与工程前沿（英文）》 2018年 第12卷 第2期 doi: 10.1007/s11783-018-1028-9

摘要： Soil remediation is of increasing importance globally, especially in developing countries. Among available remediation options, stabilization, which aims to immobilize contaminants within soil, has considerable advantages, including that it is cost-effective, versatile, sustainable, rapid, and often results in less secondary pollution. However, there are emerging challenges regarding the long-term performance of the technology, which may be affected by a range of environmental factors. These challenges stem from a research gap regarding the development of accurate, quantitative laboratory simulations of long-term conditions, whereby laboratory accelerated aging methods could be normalized to real field conditions. Therefore, field trials coupled with long-term monitoring are critical to further verify conditions under which stabilization is effective. Sustainability is also an important factor affecting the long-term stability of site remediation. It is hence important to consider these challenges to develop an optimized application of stabilization technology in soil remediation.

关键词： Stabilization     Soil remediation     Long-term     Trace metals    

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A perspective of “Nuclear Hot Spring” for long-term sustainable economy of the world

Yingzhong LU

《能源前沿（英文）》 2011年 第5卷 第4期   页码 349-357 doi: 10.1007/s11708-011-0168-4

摘要： The rapid growth of human economy in the late 20th century gave rise to great concern over sustainability of the world. A pessimistic “Full World Model” forecasts that human economy could not develop further. The nuclear fission (and fusion later), however, could release huge amount of energy to create sufficient useful material resources and turn the said pessimistic modelinto a new optimistic “Sustainable World Model”.The dilemma of nuclear energy (Military Giant vs. Civil Dwarf) jeopardizes its performance as a “Technologic Fixer”. According to Mother Nature’s teachings, the elimination of the root-causes of the design-based risk factors could solve this problem. Recent technology break-through from inherent safety to natural safety has been made in China. The proposed full-power natural circulation “Nuclear Hot Spring (NHS)” reactor could operate solely on natural forces without complex man-made coolant circulation equipment and human-operated control systems. The cheap, unlimited supply of energy from nuclear energy could change the geopolitics forever, and finally eliminate the root-causes of most international and regional conflicts.

关键词： natural safety reactor     full power natural circulation     sustainable world economy    

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Long-term exposure to air pollution and cerebrovascular disease: findings from Beijing Health Management

《环境科学与工程前沿（英文）》 2023年 第17卷 第7期 doi: 10.1007/s11783-023-1684-2

摘要：

● This study explored the long-term association by double robust additive models.

关键词： Air pollution     Cerebrovascular disease     Incidence     Long-term exposure     Doubly robust additive model    

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Effects of coarse and fine aggregates on long-term mechanical properties of sea sand recycled aggregate

《结构与土木工程前沿（英文）》 2021年 第15卷 第3期   页码 754-772 doi: 10.1007/s11709-021-0711-2

摘要： Typical effects of coarse and fine aggregates on the long-term properties of sea sand recycled aggregate concrete (SSRAC) are analyzed by a series of axial compression tests. Two different types of fine (coarse) aggregates are considered: sea sand and river sand (natural and recycled coarse aggregates). Variations in SSRAC properties at different ages are investigated. A novel test system is developed via axial compression experiments and the digital image correlation method to obtain the deformation field and crack development of concrete. Supportive results show that the compressive strength of SSRAC increase with decreasing recycled coarse aggregate replacement percentage and increasing sea sand chloride ion content. The elastic modulus of SSRAC increases with age. However, the Poisson’s ratio reduces after 2 years. Typical axial stress–strain curves of SSRAC vary with age. Generally, the effect of coarse aggregates on the axial deformation of SSRAC is clear; however, the deformation differences between coarse aggregate and cement mortar reduce by adopting sea sand. The aggregate type changes the crack characteristics and propagation of SSRAC. Finally, an analytical expression is suggested to construct the long-term stress–strain curve of SSRAC.

关键词： sea sand recycled aggregate concrete     recycled coarse aggregate replacement percentage     sea sand chloride ion content     long-term mechanical properties     stress–strain curve    

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Long-term adaptive evolution of

Yong Xiao, Changye Xiao, Feng Zhao

《环境科学与工程前沿（英文）》 2020年 第14卷 第1期 doi: 10.1007/s11783-019-1182-8

摘要： Shewanella oneidensis MR-1 was acclimated to grow with Cr(VI) of 190 mg/L. Whole genomes from 7 populations at different acclimation stages were sequenced. Gene mutations mainly related to efflux pumps and transporters. An adaptation mechanism of MR-1 to high concentration of Cr(VI) was proposed. Acclimation is the main method to enhance the productivity of microorganisms in environmental biotechnology, but it remains uncertain how microorganisms acquire resistance to high concentrations of pollutants during long-term acclimation. Shewanella oneidensis MR-1 was acclimated for 120 days with increasing hexavalent chromium (Cr(VI)) concentrations from 10 to 190 mg/L. The bacterium was able to survive from the highly toxic Cr(VI) environment due to its enhanced capability to reduce Cr(VI) and the increased cell membrane surface. We sequenced 19 complete genomes from 7 populations of MR-1, including the ancestral strain, the evolved strains in Cr(VI) environment on days 40, 80 and 120 and their corresponding controls. A total of 27, 49 and 90 single nucleotide polymorphisms were found in the Cr(VI)-evolved populations on days 40, 80 and 120, respectively. Nonsynonymous substitutions were clustered according to gene functions, and the gene mutations related to integral components of the membrane, including efflux pumps and transporters, were the key determinants of chromate resistance. In addition, MR-1 strengthened the detoxification of Cr(VI) through gene variations involved in adenosine triphosphate binding, electron carrier activity, signal transduction and DNA repair. Our results provide an in-depth analysis of how Cr(VI) resistance of S. oneidensis MR-1 is improved by acclimation, as well as a genetic understanding of the impact of long-term exposure of microorganisms to pollution.

关键词： Environmental biotechnology     Acclimation     Chromate resistance     Efflux pumps     Detoxification    

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Elucidate long-term changes of ozone in Shanghai based on an integrated machine learning method

《环境科学与工程前沿（英文）》 2023年 第17卷 第11期 doi: 10.1007/s11783-023-1738-5

摘要：

● A novel integrated machine learning method to analyze O3 changes is proposed.

关键词： Ozone     Integrated method     Machine learning    

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CONCENTRATIONS AND FLUXES OF DISSOLVED NUTRIENTS IN THE YANGTZE RIVER: LONG-TERM TRENDS AND ECOLOGICAL

《农业科学与工程前沿（英文）》 2021年 第8卷 第4期   页码 559-567 doi: 10.15302/J-FASE -2020344

摘要：

Intensifying human activity in the Yangtze River basin has substantially increased nutrient concentrations in the Yangtze River Estuary, leading to degradation of the coastal environment. Analysis of nutrient determinations published over the past 50 years reveals a gradual decreasing trend in the concentrations and fluxes of dissolved silicate (DSi). However, both dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphate (DIP) concentrations have increased significantly since the 1970s. The frequency of and area covered by red tide outbreaks have increased greatly during this period, mainly due to changes in nutrient supply ratios [i.e., N/P (DIN/DIP), N/Si (DIN/DSi), P/Si (DIP/DSi)]. A strong correlation was found between the riverine DIN fluxes and the estimated DIN inputs from the major N sources, particularly fertilizers and atmospheric deposition. The data provide a comprehensive assessment of nutrients in the Yangtze River basin and their ecological impacts and indicate a potentially significant influence of atmospheric deposition on DIN loadings and fluxes.

 

关键词： atmospheric deposition / ecological impacts / nitrogen sources / nutrients / Yangtze delta    

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Mycophenolate mofetil or tacrolimus compared with azathioprine in long-term maintenance treatment for

《医学前沿（英文）》 2022年 第16卷 第5期   页码 799-807 doi: 10.1007/s11684-021-0849-2

摘要： This study aimed to evaluate the efficacy and safety of mycophenolate mofetil (MMF) or tacrolimus (TAC) compared with azathioprine (AZA) as maintenance therapy for active lupus nephritis (ALN). Patients with ALN who responded to 24 weeks of induction treatment were enrolled. Patients who received MMF or TAC as induction therapy continued MMF or TAC treatment during the maintenance period, whereas those who received intravenous cyclophosphamide were subjected to AZA treatment. The primary endpoint was the incidence of renal relapse. Secondary endpoints included extrarenal flares and composite endpoints (deaths, end-stage renal disease, or doubling of serum creatinine levels). A total of 123 ALN patients (47 in the MMF group, 37 in the TAC group, and 39 in the AZA group) were enrolled. The median follow-up time was 60 months. Ten MMF-treated patients, ten TAC-treated patients, and eight AZA-treated patients experienced renal relapses (P = 0.844). The cumulative renal relapse rates in the MMF group (P = 0.934) and TAC group (P = 0.673) were similar to the renal relapse rate in the AZA group. No significant difference in the incidence of severe adverse event was observed among the groups. Long-term maintenance therapies with MMF or TAC might have similarly low rates of renal relapse and similar safety profiles compared with AZA.

关键词： lupus nephritis     mycophenolate mofetil     tacrolimus     maintenance therapy    

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Physiological effects of weightlessness: countermeasure system development for a long-term Chinese manned

Linjie Wang, Zhili Li, Cheng Tan, Shujuan Liu, Jianfeng Zhang, Siyang He, Peng Zou, Weibo Liu, Yinghui Li

《医学前沿（英文）》 2019年 第13卷 第2期   页码 202-212 doi: 10.1007/s11684-017-0587-7

摘要： The Chinese space station will be built around 2020. As a national space laboratory, it will offer unique opportunities for studying the physiological effects of weightlessness and the efficacy of the countermeasures against such effects. In this paper, we described the development of countermeasure systems in the Chinese space program. To emphasize the need of the Chinese space program to implement its own program for developing countermeasures, we reviewed the literature on the negative physiological effects of weightlessness, the challenges of completing missions, the development of countermeasure devices, the establishment of countermeasure programs, and the efficacy of the countermeasure techniques in American and Russian manned spaceflights. In addition, a brief overview was provided on the Chinese research and development on countermeasures to discuss the current status and goals of the development of countermeasures against physiological problems associated with weightlessness.

关键词： countermeasure     physiological effects of weightlessness     effect evaluation     long-term manned spaceflight    

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Sustainable Plasticulture in Chinese Agriculture: a Review of Challenges and Routes to Achieving Long-term

《农业科学与工程前沿（英文）》 doi: 10.15302/J-FASE-2023508

摘要：

● Macro-, micro- and nanoplastic pollution in agricultural soils threaten long-term crop production and environmental health in China.

关键词： circular plastics economy     crop production     food security     plastic pollution     sustainable plasticulture    

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Enhanced methane production during long-term UASB operation at high organic loads as enabled by the immobilized

《环境科学与工程前沿（英文）》 2022年 第16卷 第6期 doi: 10.1007/s11783-021-1505-4

摘要：

• Fungi enable the constant UASB operation even at OLR of 25.0 kg/(m3×d).

关键词： Anaerobic digestion     Fungi     Methane production     High OLR     Microbial community    

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Several issues to be considered for long-term better behavior of concrete gravity dams

Jinsheng JIA,

《结构与土木工程前沿（英文）》 2010年 第4卷 第1期   页码 40-46 doi: 10.1007/s11709-010-0006-5

摘要： Along with economic, social quick development and urbanization, dams and reservoirs are of strategic importance for flood control, water supply, electricity production, irrigation, etc., both for developed countries and for developing countries. Climate change is a new challenging issue to be considered which will speed up the development of hydropower in developing countries. More and more attention will be paid on the long-term better behavior of dams to guarantee the safety of the people involved and the better development of the world. There are about 50000 old dams in the world and a lot of them have been completed and operated for more than 50 years. However, how do we evaluate the dams’ safety? How do we make the decision to do rehabilitation work or to rebuild a new dam based on evaluation results? The life span and the real safety status of old dams becomes a challenging task for the dam society, especially for China because it has more than 6000 dams to be evaluated and rehabilitated within the next few years. Based on the investigation of the Fengman gravity dam, which is 91.7 m high, operated since 1943 and suffered uplift pressure, freeze and thaw problems, etc., discussions on the life span evaluation of old concrete gravity dams have been made. The reasonable coefficient of dam safety has been discussed. The social decision for the final choice after comprehensive studies has been introduced.

关键词： dam safety     economic life span     structural life span     environmental life span     rehabilitation     social decision    

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标题 作者 时间 类型 操作

Mechanism and control of the long-term performance evolution of structures

Zhiqiang DONG, Gang WU, Hong ZHU, Haitao WANG, Yihua ZENG

期刊论文

Enhanced 4-chlorophenol biodegradation by integrating FeO nanoparticles into an anaerobic reactor: Long-termperformance and underlying mechanism

期刊论文

Long-Term Performance and Microstructural Characterization of Dam Concrete in the Three Gorges Project

Chen Lyu,Cheng Yu,Chao Lu,Li Pan,Wenwei Li,Jiaping Liu,

期刊论文

Stabilization-based soil remediation should consider long-term challenges

Zhengtao Shen, Zhen Li, Daniel S. Alessi

期刊论文

A perspective of “Nuclear Hot Spring” for long-term sustainable economy of the world

Yingzhong LU

期刊论文

Long-term exposure to air pollution and cerebrovascular disease: findings from Beijing Health Management

期刊论文

Effects of coarse and fine aggregates on long-term mechanical properties of sea sand recycled aggregate

期刊论文

Long-term adaptive evolution of

Yong Xiao, Changye Xiao, Feng Zhao

期刊论文

Elucidate long-term changes of ozone in Shanghai based on an integrated machine learning method

期刊论文

CONCENTRATIONS AND FLUXES OF DISSOLVED NUTRIENTS IN THE YANGTZE RIVER: LONG-TERM TRENDS AND ECOLOGICAL

期刊论文

Mycophenolate mofetil or tacrolimus compared with azathioprine in long-term maintenance treatment for

期刊论文

Physiological effects of weightlessness: countermeasure system development for a long-term Chinese manned

Linjie Wang, Zhili Li, Cheng Tan, Shujuan Liu, Jianfeng Zhang, Siyang He, Peng Zou, Weibo Liu, Yinghui Li

期刊论文

Sustainable Plasticulture in Chinese Agriculture: a Review of Challenges and Routes to Achieving Long-term

期刊论文

Enhanced methane production during long-term UASB operation at high organic loads as enabled by the immobilized

期刊论文

Several issues to be considered for long-term better behavior of concrete gravity dams

Jinsheng JIA,

期刊论文