检索结果-南通市图书馆

A micro-investigation on water bridge effects for unsaturated granular materials with constant water content by discrete element method

在线全文

学校读者我要写书评

暂无评论

Particuology 2023年第12期83卷 50-62页

作者： Mengchen Li Jiyuan Luan Xuguang Gao Ji-Peng Wang Abdelali Dadda School of Civil Engineering Shandong University17922 Jingshi RoadJinan250061China

The most common state of surface soil is *** in water content will substantially impact its strength,leading to geological and engineering *** paper used LIGGGHTS software to simulate the water bridge effect of unsaturated granular materials with constant water content and verify the rationality of the simplification of the stress-force-fabric(SFF)*** results showed that the capillary force was not isotropic,which was different from the previous study,thus it cannot be overlooked in the simplification of the SFF ***,the influence of water content on the macroscopic mechanical behavior of unsaturated granular materials was interpreted through the evolutions of coordination number,interparticle force,fabric and force anisotropy,and other microscopic *** to the literature,we found that different water bridge models would not change the characteristics of the solid skeleton.

关键词： Unsaturated granular material water bridge effect water content Discrete element method Stress-force-fabric(SFF)relationship

Estimation of the PM_(2.5) effective hygroscopic parameter and water content based on particle chemical composition: Methodology and case study

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2016年第8期59卷 1683-1691页

作者： LIU YueChen WU ZhiJun TAN TianYi WANG YuJue QIN YanHong ZHENG Jing LI MengRen HU Min Department of Environmental Science Peking University

Particle hygroscopicity plays a key role in understanding the mechanisms of haze formation and particle optical properties. The present study developed a method for predicting the effective hygroscopic parameter k and the water content of PM_(2.5) on the basis of the k-K?hler theory and bulk chemical components of PM_(2.5). Our study demonstrated that the effective hygroscopic parameter can be estimated using the PM_(2.5) mass concentration, water-soluble ions, and total water-soluble carbon. By combining the estimated k and ambient relative humidity, the water content of PM_(2.5) can be further estimated. As an example, the k and water content of PM_(2.5) in Beijing were estimated utilizing the method proposed in this study. The annual average value of k of PM_(2.5) in Beijing was 0.25±0.09, the maximum k value 0.26±0.08 appeared in summer, and the seasonal variation is insignificant. The PM_(2.5) water content was determined by both the PM_(2.5) hygroscopicity and the ambient relative humidity(RH). The annual average mass ratio of water content and PM_(2.5) was 0.18±0.20, and the maximum value 0.31±0.25 appeared in summer. Based on the estimated water content of PM_(2.5) in Beijing, the relationship between the PM_(2.5) water content and RH was parameterized as: m(%)=0.03+(5.73×10^(-8)) ×RH^(3.72).This parametric formula helps to characterize the relationship between the PM_(2.5) mass concentration and atmospheric visibility.

关键词： PM2.5 Effective hygroscopic parameter water content Chemical component Relative humidity

Effect of suction change on water content and total volume of an expansive clay

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第5期8卷 699-706页

作者： ZHAN Liang-tong CHEN Ping NG C.W.W. ~ Department of Civil Engineering Zhejiang University Hangzhou 310027 China Department of Civil Engineering Zhejiang Sci- Tech University Hangzhou 310018 China Department of Civil Engineering Hong Kong University of Science and Technology Hong Kong China

A laboratory study was carried out on both natural and compacted specimens to investigate the complex soil-water interaction in an unsaturated expansive clay. The laboratory study includes the measurement of soil-water characteristic curves, 1D free swelling tests, measurement of swelling pressure and shrinkage tests. The test results revealed that the air-entry value of the natural specimen was quite low due to cracks and fissures present. The hydraulic hysteresis of the natural specimen was relatively insignificant as compared with the compacted specimen. Within a suction range 0 to 500 kPa, a bilinear relationship between free swelling strain (or swelling pressure) and initial soil suction was observed for both the natural and compacted specimens. As a result of over-consolidation and secondary structures such as cementation and cracks, the natural specimens exhibited significant lower swelling (or swelling pressure) than the compacted specimen. The change of matric suction exerts a more significant effect on the water phase than on the soil skeleton for this expansive clay.

关键词： Expansive soil water content Suction Swelling Shrinkage

Terahertz-dependent evaluation of water content in high-water-cut crude oil using additive-manufactured samplers

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2017年第4期60卷 40-44页

作者： LiMei Guan HongLei Zhan XinYang Miao Jing Zhu Kun Zhao Beijing Key Laboratory of Optical Detection Technology for Oil and Gas China University of Petroleum Beijing 102249 China

The evaluation of water content in crude oil is of significance to petroleum exploration and ***(THz) waves are sensitive to fluctuations in the dipole moment of ***,due to the strong absorption of water in the THz range,it is difficult for the THz spectrum to determine high water content with the common *** this research,micron-grade samplers for THz detection were designed and manufactured using additive manufacturing(AM) ***-water mixtures with water content from 1.8%to 90.6%were measured with the THz-TDS system using sample *** addition,a detailed analysis was performed of the relationships among THz parameters such as signal peak,time delay,and refractive index as well as absorption coefficient and high water content(>60%).Results suggest that the combination of THz spectroscopy and AM technique is effective for water content evaluation in crude oil and can be further applied in the petroleum industry.

关键词： water content crude oil additive manufacturing terahertz spectroscopy

Effects of Material Composition and water content on the Mechanical Properties of Landslide Deposits Triggered by the Wenchuan Earthquake

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2016年第1期90卷 242-257页

作者： ZHOU Jiawen CUI Peng YANG Xingguo State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology Key Laboratory of Mountain Hazards and Surface Process Chinese Academy of Sciences College of water Resource and Hydropower Sichuan University

Abundant landslide deposits were triggered by the Wenchuan earthquake, providing a rich source of material for subsequent debris flows or slope failures under rainfall conditions. A good understanding of the physical and mechanical properties of the landslide deposits is very important to the research on slope failure mechanisms and the initiation of debris flow. Laboratory biaxial compression tests are used to study the material compositions and water content impacts on the mechanical properties of landslide deposits, and a discrete element method （a bond-contact model） is used to study the particle stiffness, bond force, friction coefficient and confining stress impact on the mechanical behaviors and the relationships between the numerical and experimental parameters. The experimental results show that the failure stress of landslide deposits is decreased with increasing content of fine particles and also with increased water content, especially at the initial increasing stage. Cohesion of the saturated landslide deposits is increased, but the friction angle is decreased with the increase in the fine particle content. Shear strength parameters （the cohesion and friction angle） are decreased with the increasing water content at the initial increasing stage, and then, they slowly decrease. There is a critical value of the water content at 5%-7% （in weight） for the failure stress and shear strength parameters of the landslide deposits. Quadratic equations are presented to describe the relation between the bond force and cohesion, and the numerical friction coefficient and the experimental friction angle.

关键词： landslide deposits particle size distribution water content shear strength parameters numerical modeling

Fall cone tests considering water content, cone penetration index, and plasticity angle of fine-grained soils

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2020年第6期12卷 1347-1355页

作者： Satoru Shimobe Giovanni Spagnoli College of Science and Technology Nihon UniversityFunabashi274-8501Japan BASF Construction Solutions GmbH Dr.-Albert-Frank-Straße 32Trostberg83308Germany

This paper analyzed the consistency of some parameters of soils in the literature and experimental results from fall cone test and its application to soil plasticity *** 500 data from both literatures and experiments using fall cone and Casagrande methods were compiled to assess the relationships among specified water content,cone penetration index ebT,and plasticity angle eaT of finegrained *** results indicate that no unique correlation exists among b,liquid limit of the fall cone test(LLc)and *** water content at 1 mm cone penetration eC0T correlates well with b,plasticity ratio eRpT(*** ratio of plastic limit to liquid limit),and ***,the potential of using the btan a diagram to classify soil plasticity was also discussed.

关键词： Atterberg limits Fall cone test Plasticity angle water content Cone penetration index Plasticity ratio

Effect of Polypropylene Fiber on the Unconfined Compressive Strength of Loess with Different water content

在线全文

学校读者我要写书评

暂无评论

Journal of Renewable Materials 2023年第4期11卷 1699-1714页

作者： Wankui Ni Jiaxin Zhong Haiman Wang College of Geological Engineering and Geomatics Chang’an UniversityXi’an710054China Ningxia Institute of Survey and Monitoring of Land and Resources Yinchuan750002China

Fiber-reinforced soils have been of great interest to experimenters for building foundations’strength performance,time,and *** paper investigates the effects of water content and polypropylene fiber dosage and length on loess’s unconfined compressive strength(UCS)according to the central composite response surface design test *** water content is 11%–25%,the mass ratio of fiber to soil is 0.1%–0.9%,and the fiber length ranges from 6–18 *** response surface method(RSM)developed full quadratic models of different variables with response *** analysis of variance(ANOVA),the mathematical model developed in this study was statistically significant(p≤0.05)and applicable to the optimization *** optimization results showed that the optimal water content values,fiber amount,and fiber length were 16.41%,0.579%,and 14.90 mm,*** unconfined compressive strength of the optimized specimens was increased by 288.017 *** research results can reference the design and construction of fiber-reinforced soil in practical projects such as road base engineering and foundation engineering.

关键词： Loess polypropylene fiber response surface method water content

Influence of water content on Conductivity and Piezoresistivity of Cement-based Material with both Carbon Fiber and Carbon Black

维普期刊数据库评论

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 Wuhan University of Technology(Materials Science) 2010年第1期25卷 147-151页

作者：韩宝国欧进萍 School of Civil Engineering Harbin Institute of Technology School of Civil and Hydraulic Engineering Dalian University of Technology

The influence of water content on the conductivity and piezoresistivity of cement-based material with carbon fiber （CF） and carbon black （CB） was investigated. The piezoresistivity of cement-based material with both CF and CB was compared with that of cement-based material with CF only, and the changes in electrical resistivity of cement-based material with both CF and CB under static and loading conditions in different drying and soaking time were studied. It is found that the piezoresistivity of cement-based material with both CF and CB has better repeatability and linearity than that of cement-based material with CF only. The conductivity and the sensitivity of piezoresistive cement-based material with both CF and CB are enhanced as the water content in piezoresistive cement-based material increases.

关键词： cement-based material carbon fiber carbon black water content conductivity piezoresistivity

A simple method for determining water content in organic solvents based on cobalt(Ⅱ) complexes

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2011年第2期22卷 189-192页

作者： Lin Zhou Xiao Hua Liu Hai Xin Bai Hong Juan Wang College of Plant Protection Henan Agricultural UniversityZhengzhou 450002China College of Sciences Henan Agricultural UniversityZhengzhou 450002China

A method to determine water content in organic solvents was developed based on the color change of cobalt（Ⅱ） nitrate in different *** color-change mechanism and optimal conditions for determining the water content were *** results showed that there was a good linear relationships between the absorbance of cobalt（Ⅱ） complexes in organic solvents and water contents withγin 0.9989～*** method has the advantages of low cost,good reproducibility,good sensitivity,simple in operation,fast in detection,friendly to the environment and no limitation on linear range for determining water *** was used to determine water in samples with a satisfactory recovery in 97.81%～101.24%.

关键词： Determination water content Cobalt(Ⅱ) nitrate Organic solvent