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Effect of nonionic side chain length of polycarboxylate-ether-based high-range water-reducing admixture

Süleyman ÖZEN, Muhammet Gökhan ALTUN, Ali MARDANI-AGHABAGLOU, Kambiz RAMYAR

《结构与土木工程前沿（英文）》 2020年 第14卷 第6期   页码 1573-1582 doi: 10.1007/s11709-020-0680-x

摘要： Despite the large variations in the behaviors of water-reducing admixtures upon changes in their structures, most previous reports on the cement-admixture compatibility did not provide sufficient information on the structure of the admixture. Hence, the evaluation and generalization of the reports on the cement-admixture compatibility are challenging. In this study, three different polycarboxylate-ether-based water-reducing admixtures with the same free nonionic content, anionic/nonionic molar ratio, and main chain length and different side chain lengths were produced. The compatibility of these admixtures with a CEM I 42.5R-type cement was investigated. In addition, an analysis of variance was performed on the experiment results to evaluate the contributions of the admixture type, admixture/cement ratio, and elapsing time to the Marsh funnel flow time, mini-slump, slump flow, and compressive strength. The water-reducing admixtures having long or short side chains reduced the initial flow characteristics of the cementitious systems. However, the admixture having the shortest side chain was better with regard to flow retention. The side chain length of the admixture did not have significant effects on the compressive strength and water absorption capacity of the mortar mixtures and mini-slump performances of the cement paste mixtures. Regarding the behaviors of the admixtures in the cementitious systems, an optimal admixture side chain molecular weight is proposed.

关键词： water-reducing admixture     side chain length     cement paste     fluidity     compressive strength    

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聚羧酸系减水剂在客运专线工程中的应用研究

黄直久

《中国工程科学》 2009年 第11卷 第1期   页码 75-80

摘要：

介绍聚羧酸系减水剂在满足铁路客运专线高性能混凝土综合性能方面的能力和特点，分析了工程应用中使用聚羧酸系减水剂存在的一些问题。提出解决聚羧酸系减水剂与水泥的相容性问题以及保持聚羧酸系减水剂本身质量稳定性是目前该减水剂应用的关键。

关键词： 聚羧酸系减水剂     水泥的相容性     质量稳定性     高性能混凝土    

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Effect of mineral additives and permeability reducing admixtures having different action mechanisms on

《结构与土木工程前沿（英文）》 2021年 第15卷 第5期   页码 1277-1291 doi: 10.1007/s11709-021-1752-2

摘要： In this paper, the effect of usage of the permeability reducing admixture (PRA) having different action mechanisms on hardened state properties of cementitious systems containing mineral additives is examined. For this aim, three commercial PRAs were used during investigation. The effective parameters in the first and third PRAs were air-entraining and high-rate air-entraining, respectively. The second one contained the insoluble calcium carbonate residue and had a small amount of the air-entraining property. Mortar mixes with binary and ternary cementitious systems were prepared by partially replacing cement with fly ash and metakaolin. The hardened state properties of mortar mixtures such as compressive strength, ultrasonic pulse velocity, water absorption, drying shrinkage and freeze–thaw resistance were investigated. The ternary cement-based mixture having both fly ash and metakaolin was selected as the most successful mineral-additive bearing mix in regard to hardened state properties. In this sense, PRA-B, with both insoluble residues and a small amount of air-entraining properties, showed the best performance among the mixtures containing PRA. The combined use of mineral additive and PRA had a more positive effect on the properties of the mixes.

关键词： cementitious system     mineral additive     permeability reducing admixture     mechanical properties     durability performance    

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Feasibility of crack free reinforced concrete bridge deck from materials composition perspective: a state of the art review

Mahdi AREZOUMANDI

《结构与土木工程前沿（英文）》 2015年 第9卷 第1期   页码 91-103 doi: 10.1007/s11709-015-0274-1

摘要： Early age cracking on bridge deck has been the subject of many studies for years. Cracking is a major concern because it leads to premature deterioration of structures. Millions of dollars spent to repair the cracked bridge decks each year. To design an appropriate mixture for crack free bridge deck, it is important to study previous researches. This paper presents a comprehensive literature review of the performance of different materials compositions as well as methods have been used to reduce and control bridge deck cracks. Different material compositions and methods are discussed in terms of their performances as well as advantages and disadvantages.

关键词： bridge deck     crack     fiber     shrinkage     shrinkage reducing admixture    

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An experimental study for optimization of high range water reducing superplasticizer in self compacting

Rahul DUBEY, Pardeep KUMAR

《结构与土木工程前沿（英文）》 2013年 第7卷 第1期   页码 62-71 doi: 10.1007/s11709-013-0192-z

摘要： Concrete is extensively used construction material in the infrastructure development industry. With increase in technical knowhow, the need of research for high performance concretes such as self-compacting concrete (SCC) has increased in the last decade. The adaptability of SCC is due to its fluidic behavior in fresh state. However, to develop SCC using indigenous materials, the lack of standardized mix design procedures is the biggest impediment. Although with the advent of chemical admixtures, it is possible to achieve concrete with high fluidity, but at the same time durability issues require more attention. To have these fresh state properties SCC mixes are typically designed with high powder contents, and chemical admixtures. Proportioning and optimization of these materials is a key issue in the mix design of SCC. This paper focuses mainly on experimental study to optimize dosages of superplasticizer for mortar of SCC and then in concrete mixture itself.

关键词： self-compacting concrete (SCC)     fresh properties     superplasticizer     optimization     compressive strength    

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Chemical additives affect sulfate reducing bacteria biofilm properties adsorbed on stainless steel 316Lsurface in circulating cooling water system

Yu Qi,Jin Li,Rui Liang,Sitong Ji,Jianxiang Li,Meng Liu

《环境科学与工程前沿（英文）》 2017年 第11卷 第2期 doi: 10.1007/s11783-017-0917-7

摘要： There are more polysaccharides than proteins in EPS on SS316L surface. NaClO cuts down more protein, while 1227 reduced more polysaccharides in EPS. HEDP slightly eased the corrosion, NaClO and 1227 inhibited the microbial corrosion. NaClO still performed pitting corrosion properties to some extent. 1227 changed the C:O and NaClO decreased the amidogen in SS316L surface film. This paper studied the biofilm properties and corrosion behavior of sulfate reducing bacteria (SRB) on stainless steel 316L (SS316L) surface in circulating cooling water system with and without additives including hydroxy ethyl fork phosphonic acid (HEDP), dodecyl dimethyl benzyl ammonium chlotide (1227) and NaClO. Biochemical technique, electrochemical technology, X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were used. The results show that the extracellular polymeric substance (EPS) in biofilm attached on the SS316L surface mainly contain proteins and polysaccharides, the contents are 98 ug·cm and 635ug·cm , respectively. The polysaccharides were cut by 1227 about 80%, while 55% by NaClO. The proteins were reduced by NaClO about 53%, while only 30% by 1227. The potentiodynamic polarization shows that the corrosion potential of SS316L was enhanced from −0.495 V to −0.390 V by the chemical additives, delaying the occurrence of the corrosion. And the corrosion rate was also reduced from 5.19 × 10 mm·a to 2.42 × 10 mm·a . But NaClO still caused pitting corrosion after sterilizing the bacteria, while 1227 can form a protective film on the surface of SS316L. Though HEDP contribute to the bacteria activity, it can enhance the breakdown potential. XPS results confirmed that 1227 can change the value of C:O in the biofilm attached on metal surface, and NaClO can eliminate the existence of amidogen. This study would provide some recommendations for the selection of chemical additives in the thermal power plant.

关键词： Sulfate reducing bacteria (SRB)     Chemical additives     Biofilm     Extracellular polymeric substance (EPS)     Microbe Corrosion    

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Reductant-assisted polydopamine-modified membranes for efficient water purification

Feng Sun, Jinren Lu, Yuhong Wang, Jie Xiong, Congjie Gao, Jia Xu

《化学科学与工程前沿（英文）》 2021年 第15卷 第1期   页码 109-117 doi: 10.1007/s11705-020-1987-9

摘要： Surface engineering with polydopamine coatings has been considered a promising surface functionalisation tool. However, it is difficult to control the self-polymerisation for polydopamine formation, which usually causes severe interparticle aggregation. In this study, polydopamine self-polymerisation was controlled by adjusting its reducing environment using a reductant (NaBH ) to fabricate mixed cellulose ester (MCE)/polydopamine membranes. An oxidising environment using NaIO was additionally tested as the control. The results showed that a thin polydopamine coating with small polydopamine particles was formed on the skeleton frameworks of the MCE membrane with NaBH , and the self-polymerisation rate was suppressed. The polydopamine coating formed in the reducing environment facilitated excellent water transport performance with a water permeance of approximately 400 L·m ·h ·bar as well as efficient organic foulant removal with a bovine serum albumin rejection of approximately 90%. In addition, the polydopamine coating with NaBH exhibited both excellent chemical stability and anti-microbial activity, demonstrating the contribution of the reducing environment to the performance of the MCE/polydopamine membranes. It shows significant potential for use in water purification.

关键词： membrane     water purification     polydopamine     reducing environment     self-polymerization control    

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Online control of biofilm and reducing carbon dosage in denitrifying biofilter: pilot and full-scale

Xiuhong Liu, Hongchen Wang, Qing Yang, Jianmin Li, Yuankai Zhang, Yongzhen Peng

《环境科学与工程前沿（英文）》 2017年 第11卷 第1期 doi: 10.1007/s11783-017-0895-9

摘要： Online control of DNBF was studied in the pilot-scale and full-scale experiments. DNBF was controlled by the online monitored effluent nitrate and turbidity. The effluent nitrate lower than 3 mg·L and saving 18% of carbon were both achieved. Denitrifying biofilter (DNBF) is widely used for advanced nitrogen removal in the reclaimed wastewater treatment plants (RWWTPs). Manual control of DNBF easily led to unstable process performance and high cost. Consequently, there is a need to automatic control of two decisive operational processes, carbon dosage and backwash, in DNBF. In this study, online control of DNBF was investigated in the pilot-scale DNBF (600 m ·d ), and then applied in the full-scale DNBF (10 × 104 m3·d ). A novel simple online control strategy for carbon dosage with the effluent nitrate as the sole control parameter was designed and tested in the pilot-scale DNBF. Backwash operation was optimized based on the backwash control strategy using turbidity as control parameter. Using the integrated control strategy, in the pilot-scale DNBF, highly efficient nitrate removal with effluent TN level lower than 3 mg·L was achieved and DNBF was not clogged any more. The online control strategy for carbon dosage was successfully applied in a RWWTP. Using the online control strategy, the effluent nitrate concentration was controlled relatively stable and carbon dosage was saved for 18%.

关键词： Reclaimed water treatment     Denitrifying biofilter     Carbon dosage     Backwash control    

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Can crop science really help us to produce more better-quality food while reducing the world-wide environmental

William J. DAVIES, Susan E. WARD, Alan WILSON

《农业科学与工程前沿（英文）》 2020年 第7卷 第1期   页码 28-44 doi: 10.15302/J-FASE-2019299

摘要：

This paper reviews recent developments in crop science that can be the basis of a revolution in the global food system but it is also emphasized that such a revolution requires more than changes in food production and supply. We must more effectively feed a growing global population with a healthy diet while also defining and delivering the kinds of sustainable food systems that will minimise damage to our planet. There are exciting new developments in crop production biology but much existing crop science can be exploited to increase yields with the aid of a knowledge exchange (KE) framework requiring the use of new technology now available to most people across the globe. We discuss novel approaches at both the plant and the crop level that will enhance nutrient and water productivity and we also outline ways in which energy use and greenhouse gas (GHG) emissions can be reduced and labor shortages combatted. Exploitation of new biology and new engineering opportunities will require development of public-private partnerships and collaborations across the disciplines to allow us to move effectively from discovery science to practical application. It is also important that consumers contribute to the debate over proposed changes to food and farming and so effective KE mechanisms are required between all relevant communities.

关键词： food security     environmental sustainability     crop water use efficiency     crop science     diet and health    

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三维编织锥体织物的减纱技术

朱建勋

《中国工程科学》 2006年 第8卷 第3期   页码 66-69

摘要：

研究了由大端直径开始编织三维锥体织物的减纱技术，包括列向、环向减锭减纱、减细纤维束减纱等多种减纱技术及其组合；分析比较了各种减纱技术对织物结构完整性、操作简便性、机械化编织等方面的影响。减细纤维束减纱技术是特殊的环向减锭技术，具有保持织物结构整体完整、工艺操作简便、纱锭运动可实现机械化等优点，但不同纱束直径纤维编织使织物单元结构构造变得复杂多变。

关键词： 三维编织     锥体织物     减锭减纱     减细纤维束减纱     单元构造    

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Removal of Cu(II) and Fe(III) from aqueous solutions by dead sulfate reducing bacteria

Hong’en QUAN, He BAI, Yang HAN, Yong KANG, Jiao SUN

《化学科学与工程前沿（英文）》 2013年 第7卷 第2期   页码 177-184 doi: 10.1007/s11705-013-1324-7

摘要： The biosorption properties of dead sulfate reducing bacteria (SRB) for the removal of Cu(II) and Fe(III) from aqueous solutions was studied. The effects of the biosorbent concentration, the initial pH value and the temperature on the biosorption of Cu(II) and Fe(III) by the SRB were investigated. FTIR analysis verified that the hydroxyl, carbonyl and amine functional groups of the SRB biosorbent were involved in the biosorption process. For both Cu(II) and Fe(III), an increase in the SRB biosorbent concentration resulted in an increase in the removal percentage but a decrease in the amount of specific metal biosorption. The maximum specific metal biosorption was 93.25 mg?g at pH 4.5 for Cu(II) and 88.29 mg?g at pH 3.5 for Fe(III). The temperature did not have a significant effect on biosorption. In a binary metal system, the specific biosorption capacity for the target metal decreased when another metal ion was added. For both the single metal and binary metal systems, the biosorption of Cu(II) and Fe(III) onto a SRB biosorbent was better represented by a Langmuir model than by a Freundlich model.

关键词： sulfate reducing bacteria     biosorption     Cu(II)     Fe(III)    

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关于我国地铁建设降低投资问题

施仲衡

《中国工程科学》 2001年 第3卷 第1期   页码 36-39

摘要：

文章本着技术先进，安全可靠，经济实用的原则，对降低地铁造价的可能性进行分析，提出了如下初步设想：充分作好前期准备工作；重视客流预测；考虑提高行车密度；选择合理的车站结构型式和埋深；合理确定车站设备用房和管理用房的面积；重视换乘站的设计；采用合理的车站间距；做好地下线与高架线的选择；隧道埋深、结构尺寸及施工方案的优化；切实贯彻设备国产化政策。

关键词： 地铁建设     投资     降低    

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Transportation: meeting the dual challenges of achieving energy security and reducing greenhouse gas

Michael Quanlu WANG, Hong HUO

《能源前沿（英文）》 2009年 第3卷 第2期   页码 212-225 doi: 10.1007/s11708-009-0016-y

摘要： As the population and economy continue to grow globally, demand for energy will continue to grow. The transportation sector relies solely on petroleum for its energy supply. The United States and China are the top two oil-importing countries. A major issue both countries face and are addressing is energy insecurity as a result of the demand for liquid fuels. Improvements in the energy efficiency of vehicles and the substitution of petroleum fuels with alternative fuels can help contain growth in the demand for transportation oil. Although most alternative transportation fuels - when applied to advanced vehicle technologies - can substantially reduce greenhouse emissions, coal-based liquid fuels may increase greenhouse gas emissions by twice as much as gasoline. Such technologies as carbon capture and storage may need to be employed to manage the greenhouse gas emissions of coal-based fuels. At present, there is no ideal transportation fuel option to solve problems related to transportation energy and greenhouse gas emissions. To solve these problems, research and development efforts are needed for a variety of transportation fuel options and advanced vehicle technologies.

关键词： transportation energy     energy security     greenhouse gases     alternative fuels     vehicle technologies    

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Capacity estimation and preliminary strategy for reducing the release of dioxins in China

YU Gang, ZHANG Qing, HUANG Jun, CAI Zhenxiao, SUI Qian

《环境科学与工程前沿（英文）》 2007年 第1卷 第1期   页码 13-17 doi: 10.1007/s11783-007-0002-8

摘要： As a party of the Stockholm Convention on Persistent Organic Pollutants, China must submit its national implementation plan (NIP) for this convention. The strategy and action plan for reducing the release of dioxins in China are the most important components of the NIP. Three problems are key points for developing such strategy and action plan what are the key sources for applying the best available technology/best environmental practice (BAT/BEP) to reduce the release of dioxins? How about the capacity for reducing the dioxins release from the key sources? Where are the areas of priority for applying BAT/BEP? This paper shows the efforts towards the solution of these problems. The list of key sources covering about half of the total dioxins release was determined considering four criteria. The capacity of key sources were estimated based on the difference between the emission factor corresponding to the actual situation in 2004 and that corresponding to the scenario that all key sources have been applied BAT/BEP to reduce the dioxins release. The priority analysis using the geographical information system (GIS) tool has revealed that eastern provinces should be of high priority in the future reduction activities of dioxins release in China.

关键词： GIS     difference     capacity     scenario     implementation    

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Numerical study of EGR effects on reducing the pressure rise rate of HCCI engine combustion

Gen CHEN, Norimasa IIDA, Zuohua HUANG,

《能源前沿（英文）》 2010年 第4卷 第3期   页码 376-385 doi: 10.1007/s11708-010-0118-6

摘要： The effects of the inert components of exhaust gas recirculation (EGR) gas on reducing the pressure rise rate of homogeneous charge compression ignition engine combustion were investigated numerically by utilizing the CHEMKIN II package and its SENKIN code, as well as Curran’s dimethyl ether reaction scheme. Calculations were conducted under constant volume combustion and engine combustion (one compression and one expansion only, respectively) conditions. Results show that with constant fuel amount and initial temperature and pressure, as EGR ratio increases, combustion timings are retarded and the duration of thermal ignition preparation extends non-linearly; peak values of pressure, pressure rising rate (PRR), and temperature decrease; and peak values of heat release rate in both low temperature heat release (LTHR) and high temperature heat release decrease. Moreover, maximum PRR decreases as CA50 is retarded. With constant fuel amount, mixtures with different EGR ratios can obtain the same CA50 by adjusting the initial temperature. Under the same CA50, as EGR ratio increases, the LTHR timing is advanced and the duration of thermal ignition preparation is extended. Maximum PRR is almost constant with the fixed CA50 despite the change in EGR ratio, indicating that the influence of EGR dilution on chemical reaction rate is offset by other factors. Further investigation on the mechanism of this phenomenon is needed.

关键词： HCCI engine     combustion     EGR     DME     CA50     PRR    

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标题 作者 时间 类型 操作

Effect of nonionic side chain length of polycarboxylate-ether-based high-range water-reducing admixture

Süleyman ÖZEN, Muhammet Gökhan ALTUN, Ali MARDANI-AGHABAGLOU, Kambiz RAMYAR

期刊论文

聚羧酸系减水剂在客运专线工程中的应用研究

黄直久

期刊论文

Effect of mineral additives and permeability reducing admixtures having different action mechanisms on

期刊论文

Feasibility of crack free reinforced concrete bridge deck from materials composition perspective: a state of the art review

Mahdi AREZOUMANDI

期刊论文

An experimental study for optimization of high range water reducing superplasticizer in self compacting

Rahul DUBEY, Pardeep KUMAR

期刊论文

Chemical additives affect sulfate reducing bacteria biofilm properties adsorbed on stainless steel 316Lsurface in circulating cooling water system

Yu Qi,Jin Li,Rui Liang,Sitong Ji,Jianxiang Li,Meng Liu

期刊论文

Reductant-assisted polydopamine-modified membranes for efficient water purification

Feng Sun, Jinren Lu, Yuhong Wang, Jie Xiong, Congjie Gao, Jia Xu

期刊论文

Online control of biofilm and reducing carbon dosage in denitrifying biofilter: pilot and full-scale

Xiuhong Liu, Hongchen Wang, Qing Yang, Jianmin Li, Yuankai Zhang, Yongzhen Peng

期刊论文

Can crop science really help us to produce more better-quality food while reducing the world-wide environmental

William J. DAVIES, Susan E. WARD, Alan WILSON

期刊论文

三维编织锥体织物的减纱技术

朱建勋

期刊论文

Removal of Cu(II) and Fe(III) from aqueous solutions by dead sulfate reducing bacteria

Hong’en QUAN, He BAI, Yang HAN, Yong KANG, Jiao SUN

期刊论文

关于我国地铁建设降低投资问题

施仲衡

期刊论文

Transportation: meeting the dual challenges of achieving energy security and reducing greenhouse gas

Michael Quanlu WANG, Hong HUO

期刊论文

Capacity estimation and preliminary strategy for reducing the release of dioxins in China

YU Gang, ZHANG Qing, HUANG Jun, CAI Zhenxiao, SUI Qian

期刊论文

Numerical study of EGR effects on reducing the pressure rise rate of HCCI engine combustion

Gen CHEN, Norimasa IIDA, Zuohua HUANG,

期刊论文