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Behavior of steel fiber–reinforced high-strength concrete at medium strain rate

Chujie JIAO, Wei SUN, Shi HUAN, Guoping JIANG

《结构与土木工程前沿（英文）》 2009年 第3卷 第2期   页码 131-136 doi: 10.1007/s11709-009-0027-0

摘要： Impact compression experiments for the steel fiber–reinforced high-strength concrete (SFRHSC) at medium strain rate were conducted using the split Hopkinson press bar (SHPB) testing method. The volume fractions of steel fibers of SFRHSC were between 0 and 3%. The experimental results showed that, when the strain rate increased from threshold value to 90 s , the maximum stress of SFRHSC increased about 30%, the elastic modulus of SFRHSC increased about 50%, and the increase in the peak strain of SFRHSC was 2-3 times of that in the matrix specimen. The strength and toughness of the matrix were improved remarkably because of the superposition effect of the aggregate high-strength matrix and steel fiber high-strength matrix. As a result, under impact loading, cracks developed in the SFRHSC specimen, but the overall shape of the specimen remained virtually unchanged. However, under similar impact loading, the matrix specimens were almost broken into small pieces.

关键词： steel fiber–reinforced high-strength concrete (SFRHSC)     high strain rates     split Hopkinson press bar (SHPB)     strain rate hardening effects    

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Strengthening of the concrete face slabs of dams using sprayable strain-hardening fiber-reinforced cementitious

《结构与土木工程前沿（英文）》 2022年 第16卷 第2期   页码 145-160 doi: 10.1007/s11709-022-0806-4

摘要： In this study, sprayable strain-hardening fiber-reinforced cementitious composites (FRCC) were applied to strengthen the concrete slabs in a concrete-face rockfill dam (CFRD) for the first time. Experimental, numerical, and analytical investigations were carried out to understand the flexural properties of FRCC-layered concrete slabs. It was found that the FRCC layer improved the flexural performance of concrete slabs significantly. The cracking and ultimate loads of a concrete slab with an 80 mm FRCC layer were 132% and 69% higher than those of the unstrengthened concrete slab, respectively. At the maximum crack width of 0.2 mm, the deflection of the 80-mm FRCC strengthened concrete slab was 144% higher than that of the unstrengthened concrete slab. In addition, a FE model and a simplified analytical method were developed for the design and analysis of FRCC-layered concrete slabs. Finally, the test result of FRCC leaching solution indicated that the quality of the water surrounding FRCC satisfied the standard for drinking water. The findings of this study indicate that the sprayable strain-hardening FRCC has a good potential for strengthening hydraulic structures such as CFRDs.

关键词： strain-hardening cementitious composites     engineered cementitious composites     sprayable     shotcrete     strengthening     concrete-face rockfill dam     digital image correlation    

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Stress-strain relationship with soil structural parameters of collapse loess

SHAO Shengjun, LONG Jiyong, YU Qinggao

《结构与土木工程前沿（英文）》 2008年 第2卷 第2期   页码 151-160 doi: 10.1007/s11709-008-0020-z

摘要： Through the tri-axial shearing tests of unsaturated intact loess and based on the concept of comprehensive soil structural potential, this paper reveals the changing laws of soil structural property under the tri-axial stress conditions and establishes a mathematical expression equation of structural parameters, whereby reflecting the effects of unsaturated loess water content, stress and strain states, which is introduced into the shearing stress and shearing strain relation to obtain the structural stress-strain relation. The tests reveal that the loess dilatancy is of shearing contraction and shearing expansion, whereby indicating that there is a good linear relation between the stress ratio and shearing expansion strain ratio. The larger consolidation confining pressure is, the larger the stress of shearing contraction and expansion critical point is; and the larger water content is, the smaller the strain ratio of shearing contraction and expansion critical point is. Finally, the constitutive model is established to reflect the variation in loess structure, stress-strain softening and hardening, and shearing contraction and shearing expansion features. Through the comparative analysis, the stress-strain curves described by the constitutive relationship are found to be in good conformity with test results, whereby testing the rationality of the model in this paper.

关键词： hardening     shearing expansion     unsaturated     structural property     mathematical expression    

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Effect of loading rate on shear strength parameters of mechanically and biologically treated waste

《环境科学与工程前沿（英文）》 2022年 第16卷 第12期 doi: 10.1007/s11783-022-1595-7

摘要：

● Mechanical behavior of MBT waste affected by loading rate was investigated.

关键词： Mechanically and biologically treated waste     Landfill     Triaxial test     Loading rate     Axial strain     Shear strength parameter    

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The combined effects of biomass and temperature on maximum specific ammonia oxidation rate in domestic

《环境科学与工程前沿（英文）》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1411-9

摘要：

• Actual SAORs was determined using MLVSS and temperature.

关键词： Specific ammonia oxidation rate     Sequencing batch reactor     Biomass     Temperature coefficient     Model simulation    

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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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材料的一种新型应力应变模型

张于贤,王红

《中国工程科学》 2007年 第9卷 第8期   页码 88-91

摘要：

为研究自增强超高压容器的残余应力，提出了一个新型的应力应变模型，该模型比别的模型更接近于自增强超高压容器用钢的实际工作情况；以某材料为例介绍了确定该新型模型的方法，并对其误差进行了分析，论述了由一般的拉伸曲线求解该新型的应力应变关系模型的可行性及可靠性。

关键词： 低合金高强度钢     自增强     应力应变模型     硬化参数    

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Achieving High Strength and Tensile Ductility in Pure Nickel by Cryorolling with Subsequent Low-Temperature Short-Time Annealing

Zhide Li,Hao Gu,Kaiguang Luo,Charlie Kong,Hailiang Yu,

《工程（英文）》 doi: 10.1016/j.eng.2023.01.019

摘要： ty. In this study, cryorolling under different strains followed by low-temperature short-time annealing was used to fabricate pure nickel sheets combining high strength with good ductility. The results show that, for different cryorolling strains, the uniform elongation was greatly increased without sacrificing the strength after annealing. A yield strength of 607 MPa and a uniform elongation of 11.7% were obtained after annealing at a small cryorolling strain (ε = 0.22), while annealing at a large cryorolling strain (ε = 1.6) resulted in a yield strength of 990 MPa and a uniform elongation of 6.4%. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and electron backscattered diffraction (EBSD) were used to characterize the microstructure of the specimens and showed that the high strength could be attributed to strain hardening during cryorolling, with an additional contribution from grain refinement and the formation of dislocation walls. The high ductility could be attributed to annealing twins and micro-shear bands during stretching, which improved the strain hardening capacity. The results show that the synergistic effect of strength and ductility can be regulated through low-temperature short-time annealing with different cryorolling strains, which provides a new reference for the design of future thermo-mechanical processes.

关键词： Cryorolling     Annealing     Nickel     Strain hardening     Ductility    

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An investigation of ballistic response of reinforced and sandwich concrete panels using computational techniques

Mohammad HANIFEHZADEH, Bora GENCTURK

《结构与土木工程前沿（英文）》 2019年 第13卷 第5期   页码 1120-1137 doi: 10.1007/s11709-019-0540-8

摘要： Structural performance of nuclear containment structures and power plant facilities is of critical importance for public safety. The performance of concrete in a high-speed hard projectile impact is a complex problem due to a combination of multiple failure modes including brittle tensile fracture, crushing, and spalling. In this study, reinforced concrete (RC) and steel-concrete-steel sandwich (SCSS) panels are investigated under high-speed hard projectile inpact. Two modeling techniques, smoothed particle hydrodynamics (SPH) and conventional finite element (FE) analysis with element erosion are used. Penetration depth and global deformation are compared between doubly RC and SCSS panels in order to identify the advantages of the presence of steel plates over the reinforcement layers. A parametric analysis of the front and rear plate thicknesses of the SCSS configuration showed that the SCSS panel with a thick front plate has the best performance in controlling the hard projectile. While a thick rear plate is effective in the case of a large and soft projectile as the plate reduces the rear deformation. The effects of the impact angle and impact velocity are also considered. It was observed that the impact angle for the flat nose missile is critical and the front steel plate is effective in minimizing penetration depth.

关键词： concrete panels     projectile impact     finite element modeling     smoothed particle hydrodynamics     strain rate effect    

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Inhibitive effects of three compositae plants on

Weihao ZHANG, Fuqing XU, Wei HE, Xing ZHENG, Chen YANG

《环境科学与工程前沿（英文）》 2009年 第3卷 第1期   页码 48-55 doi: 10.1007/s11783-008-0065-1

摘要： Based on common phenomena of biochemical interaction between plants and microorganisms, the inhibitive effects of three common terrestrial compositae plants, namely DC., (L.) Cronq., and (L.) Sch.-Bip. on the blue algae was studied. Live compositae plants are co-cultivated with algae in two different inoculation doses for 10 days in 5-pools incubators, in order to exclude the influence of bacteria and nutrients. The results show that DC has the most inhibitive potential among the three plants as evidenced by the most drastic decrease in optical density (OD ) of the algae. The inhibition rate is 93.3% (with initial inoculation dose of 2.0 × 10 Cells/mL) and 89.3% (with initial inoculation dose of 4.0 × 10 Cells/mL) respectively on the 10 day of cultivation. The average inhibition rate during the later half of the experiment is 0.76 (with initial inoculation dose of 2.0 × 10 Cells/mL) and 0.71 (with initial inoculation dose of 4.0 × 10 Cells/mL), respectively. Logistic model analysis shows that compositae plants such as DC. causes the reduction of the habitat's carrying capacity of algae. ANOVA analysis is used to determine the similarity and differences between every experimental group and an average inhibitive rate model is used to evaluate the inhibition effects. The results show that DC., which grow well in the aquatic environment, may have a great potential in controlling algae bloom in eutrophic water.

关键词： allelopathy     compositae plants     Microcystis aeruginosa     inhibition rate     logistic model analysis    

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Long-term effects of various types of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors on changesin glomerular filtration rate in Korea

Seo Yeon Baik, Hyunah Kim, So Jung Yang, Tong Min Kim, Seung-Hwan Lee, Jae Hyoung Cho, Hyunyong Lee, Hyeon Woo Yim, Kun-Ho Yoon, Hun-Sung Kim

《医学前沿（英文）》 2019年 第13卷 第6期   页码 713-722 doi: 10.1007/s11684-018-0661-9

摘要： Few long-term follow-up studies have compared the changes in renal function according to the type of statin used in Korea. We compared the long-term effects of statin intensity and type on the changes in the glomerular filtration rate (GFR). We extracted data of patients who took statin for the first time. We analyzed whether or not different statins affect the changes in GFR at 3 months after baseline and 4 years after. We included 3678 patients and analyzed the changes in GFR. The GFR decreased by 3.2%±0.4% on average 4 years after the first statin prescription, indicating statistically significant deterioration (from 83.5±0.4 mL/min/1.73 m to 79.9±0.4 mL/min/1.73 m , <0.001). When comparing the GFR among different statins, significant differences were observed between atorvastatin and fluvastatin (−5.3%±0.7% vs. 1.2%±2.2%, <0.05) and between atorvastatin and simvastatin (−5.3%±0.7% vs. −0.7%±0.8%, <0.05). In pitavastatin (odds ratio [OR]=0.64, 95% confidence interval [CI]=0.46–0.87, <0.005) and simvastatin (OR=0.69, 95% CI=0.53–0.91, <0.008), the GFR rate that decreased by<60 mL/min/1.73 m was significantly lower than that of atorvastatin. Regarding long-term statin intake, GFR changed with the type of statin. This work is the first in Korea to compare each statin in terms of changes in the GFR after the statin prescription.

关键词： statin     glomerular filtration rate     HMG-CoA reductase inhibitor     chronic kidney disease    

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Performance of soft-hard-soft (SHS) cement based composite subjected to blast loading with consideration of interface properties

Jun WU,Xuemei LIU

《结构与土木工程前沿（英文）》 2015年 第9卷 第3期   页码 323-340 doi: 10.1007/s11709-015-0301-2

摘要： This paper presents a combined experimental and numerical study on the damage and performance of a soft-hard-soft (SHS) multi-layer cement based composite subjected to blast loading which can be used for protective structures and infrastructures to resist extreme loadings, and the composite consists of three layers of construction materials including asphalt concrete (AC) on the top, high strength concrete (HSC) in the middle, and engineered cementitious composites (ECC) at the bottom. To better characterize the material properties under dynamic loading, interface properties of the composite were investigated through direct shear test and also used to validate the interface model. Strain rate effects of the asphalt concrete were also studied and both compressive and tensile dynamic increase factor (DIF) curves were improved based on split Hopkinson pressure bar (SHPB) test. A full-scale field blast test investigated the blast behavior of the composite materials. The numerical model was established by taking into account the strain rate effect of all concrete materials. Furthermore, the interface properties were also considered into the model. The numerical simulation using nonlinear finite element software LS-DYNA agrees closely with the experimental data. Both the numerical and field blast test indicated that the SHS composite exhibited high resistance against blast loading.

关键词： high strength concrete (SHS)     engineered cementitious composite     interface     blast test     strain rate effect    

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Effects of operating conditions on membrane charge property and nanofiltration

Li XU, Li-Shun DU, Jing HE

《化学科学与工程前沿（英文）》 2011年 第5卷 第4期   页码 492-499 doi: 10.1007/s11705-011-1143-7

摘要： The effects of the operating pressure, cross flow velocity, feed concentration, and temperature on the streaming and Zeta potential of the membranes were studied. The permeate flux and the retention rate under different nanofiltration operating conditions were also investigated. The results show that the higher pressure, feed concentration, temperature, and lower cross flow velocity lead to the higher absolute value of streaming and Zeta potential. The permeate flux of the nanofiltration decreases with the feed concentration and increases with not only the pressure but also the cross flow velocity and temperature. The higher the pressure and the cross flow velocity, the higher the retention rate. The lower feed concentration and higher temperature leads to lower retention rate. The effects of the operating conditions on the permeate flux and the retention rate were explained by the variation of the membrane charge property.

关键词： nanofiltration membrane     streaming potential     Zeta potential     permeate flux     retention rate    

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Printability and hardening performance of three-dimensionally-printed geopolymer based on lunar regolith

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0003-0

摘要： Using an in situ lunar regolith as a construction material in combination with 3D printing not only reduces the weight of materials carried from the Earth but also improves the automation of lunar infrastructure construction. This study aims to improve the printability of a geopolymer based on a BH-1 lunar regolith simulant, including the extrudability, open time, and buildability, by controlling the temperature and adding admixtures. Rheological parameters were used to represent printability with different water-to-binder ratios, printing temperatures, and contents of additives. The mechanical properties of the hardening geopolymer with different filling paths and loading directions were tested. The results show that heating the printed filaments with a water-to-binder ratio of 0.32 at 80 °C can adjust the printability without adding any additive, which can reduce the construction cost of lunar infrastructure. The printability of the BH-1 geopolymer can also be improved by adding 0.3% Attagel-50 and 0.5% polypropylene fiber by mass at a temperature of 20 °C to cope with the changeable environmental conditions on the Moon. After curing under a simulated lunar environment, the 72-h flexural and compressive strengths of the geopolymer specimens reach 4.1 and 48.1 MPa, respectively, which are promising considering that the acceleration of gravity on the Moon is 1/6 of that on the Earth.

关键词： geopolymer     lunar regolith simulant     3D printing     rheology     printability    

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Arsenic (V) removal from groundwater by GE-HL nanofiltration membrane: effects of arsenic concentration

Xiaowei WANG, Wenjun LIU, Weifang MA, Desheng LI,

《环境科学与工程前沿（英文）》 2009年 第3卷 第4期   页码 428-433 doi: 10.1007/s11783-009-0146-9

摘要： A laboratory-scale investigation was performed to study arsenic (As (V)) removal by negatively charged GE-HL nanofiltration (NF) membrane in simulated drinking water. Effects of As (V) concentration (0–200μg·L), pH, and co-ions and counter-ions were investigated. The NF membrane presented good stability, and the rejection rates exceeded 90%. The rejection rates of As (V) decreased with the increase of As (V) concentration, while it increased with the increase of pH (reached 96% at pH 6.75). Moreover, a negative relationship was observed between the co-existing ions of Cl, Na, SO, and Ca and the removal of As (V), in which bivalent ions presented more significant effects than monovalent ions.

关键词： nanofiltration (NF)     rejection rate     co-existing ion     co-ion     counter-ion    

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标题 作者 时间 类型 操作

Behavior of steel fiber–reinforced high-strength concrete at medium strain rate

Chujie JIAO, Wei SUN, Shi HUAN, Guoping JIANG

期刊论文

Strengthening of the concrete face slabs of dams using sprayable strain-hardening fiber-reinforced cementitious

期刊论文

Stress-strain relationship with soil structural parameters of collapse loess

SHAO Shengjun, LONG Jiyong, YU Qinggao

期刊论文

Effect of loading rate on shear strength parameters of mechanically and biologically treated waste

期刊论文

The combined effects of biomass and temperature on maximum specific ammonia oxidation rate in domestic

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

材料的一种新型应力应变模型

张于贤,王红

期刊论文

Achieving High Strength and Tensile Ductility in Pure Nickel by Cryorolling with Subsequent Low-Temperature Short-Time Annealing

Zhide Li,Hao Gu,Kaiguang Luo,Charlie Kong,Hailiang Yu,

期刊论文

An investigation of ballistic response of reinforced and sandwich concrete panels using computational techniques

Mohammad HANIFEHZADEH, Bora GENCTURK

期刊论文

Inhibitive effects of three compositae plants on

Weihao ZHANG, Fuqing XU, Wei HE, Xing ZHENG, Chen YANG

期刊论文

Long-term effects of various types of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors on changesin glomerular filtration rate in Korea

Seo Yeon Baik, Hyunah Kim, So Jung Yang, Tong Min Kim, Seung-Hwan Lee, Jae Hyoung Cho, Hyunyong Lee, Hyeon Woo Yim, Kun-Ho Yoon, Hun-Sung Kim

期刊论文

Performance of soft-hard-soft (SHS) cement based composite subjected to blast loading with consideration of interface properties

Jun WU,Xuemei LIU

期刊论文

Effects of operating conditions on membrane charge property and nanofiltration

Li XU, Li-Shun DU, Jing HE

期刊论文

Printability and hardening performance of three-dimensionally-printed geopolymer based on lunar regolith

期刊论文

Arsenic (V) removal from groundwater by GE-HL nanofiltration membrane: effects of arsenic concentration

Xiaowei WANG, Wenjun LIU, Weifang MA, Desheng LI,

期刊论文