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Effects of gravel on the water absorption characteristics and hydraulic parameters of stony soil
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作者 MA Yan WANG Youqi +2 位作者 MA Chengfeng YUAN Cheng BAI Yiru 《Journal of Arid Land》 SCIE CSCD 2024年第7期895-909,共15页
The eastern foothills of the Helan Mountains in China are a typical mountainous region of soil and gravel,where gravel could affect the water movement process in the soil.This study focused on the effects of different... The eastern foothills of the Helan Mountains in China are a typical mountainous region of soil and gravel,where gravel could affect the water movement process in the soil.This study focused on the effects of different gravel contents on the water absorption characteristics and hydraulic parameters of stony soil.The stony soil samples were collected from the eastern foothills of the Helan Mountains in April 2023 and used as the experimental materials to conduct a one-dimensional horizontal soil column absorption experiment.Six experimental groups with gravel contents of 0%,10%,20%,30%,40%,and 50%were established to determine the saturated hydraulic conductivity(K_(s)),saturated water content(θ_(s)),initial water content(θ_(i)),and retention water content(θ_(r)),and explore the changes in the wetting front depth and cumulative absorption volume during the absorption experiment.The Philip model was used to fit the soil absorption process and determine the soil water absorption rate.Then the length of the characteristic wetting front depth,shape coefficient,empirical parameter,inverse intake suction and soil water suction were derived from the van Genuchten model.Finally,the hydraulic parameters mentioned above were used to fit the soil water characteristic curves,unsaturated hydraulic conductivity(K_(θ))and specific water capacity(C(h)).The results showed that the wetting front depth and cumulative absorption volume of each treatment gradually decreased with increasing gravel content.Compared with control check treatment with gravel content of 0%,soil water absorption rates in the treatments with gravel contents of 10%,20%,30%,40%,and 50%decreased by 11.47%,17.97%,25.24%,29.83%,and 42.45%,respectively.As the gravel content increased,inverse intake suction gradually increased,and shape coefficient,K_(s),θ_(s),andθ_(r)gradually decreased.For the same soil water content,soil water suction and K_(θ)gradually decreased with increasing gravel content.At the same soil water suction,C(h)decreased with increasing gravel content,and the water use efficiency worsened.Overall,the water holding capacity,hydraulic conductivity,and water use efficiency of stony soil in the eastern foothills of the Helan Mountains decreased with increasing gravel content.This study could provide data support for improving soil water use efficiency in the eastern foothills of the Helan Mountains and other similar rocky mountainous areas. 展开更多
关键词 stony soil gravel content water absorption characteristics hydraulic parameters one-dimensional horizontal soil column absorption experiment van Genuchten model eastern foothills of Helan Mountains
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Synthesis,Characterization and Water Absorption Analysis of Highly Hygroscopic Bio-based Co-polyamides 56/66 被引量:1
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作者 杜瑞满 程刊 +7 位作者 刘涛 乌彤 秦鸿彬 王学利 潘星夷 冯旭 马博谋 何勇 《Journal of Donghua University(English Edition)》 CAS 2023年第6期631-638,共8页
This study aims to develop highly hygroscopic bio-based co-polyamides(CPs)by melt co-polycondensation of polyamide(PA)56 salt and PA66 salt with varying molar fractions.The functional groups and the chemical structure... This study aims to develop highly hygroscopic bio-based co-polyamides(CPs)by melt co-polycondensation of polyamide(PA)56 salt and PA66 salt with varying molar fractions.The functional groups and the chemical structure of the prepared samples were determined by Fourier transform infrared(FTIR)spectroscopy and proton nuclear magnetic resonance(^(1)H-NMR)spectroscopy.The relative viscosity was determined with an Ubbelohde viscometer.The melting behavior and the thermal stability of CPs were investigated by differential scanning calorimetry(DSC)and thermogravimetric analysis(TGA).Furthermore,the water absorption behavior of CP hot-pressed film was studied.The results reveal that the melting point,the crystallization temperature and the crystallinity of CPs firstly decrease and then increase with the molar fraction of PA66 in CPs.The copolymerization of PA56 with PA66 leads to an obvious increase in water absorption.The CPs with PA66 molar fraction of 50%possess a high saturated water absorption rate of 17.6%,compared to 11.6%for pure PA56 and 7.8%for pure PA66. 展开更多
关键词 bio-based PA56 hygroscopic co-polyamide(CP) melt polycondensation water absorption
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Effect of Water Absorption on the Mechanical Property and Failure Mechanism of Hollow Glass Microspheres Composite Epoxy Resin Solid Buoyancy Materials
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作者 DING Yue ZHAI Gang-jun +2 位作者 MA Zhe WEI Zi-hao LI Xin 《China Ocean Engineering》 SCIE EI CSCD 2023年第5期876-884,共9页
To study the water absorption of hollow glass microspheres(HGMs)composite epoxy resin solid buoyancy materials in the marine environment and its effect on the mechanical properties,the water absorption was measured by... To study the water absorption of hollow glass microspheres(HGMs)composite epoxy resin solid buoyancy materials in the marine environment and its effect on the mechanical properties,the water absorption was measured by immersing the material in distilled water for 36 days at ambient temperature and fitted to Fick’s second law.The strength of materials before and after water absorption were tested by uniaxial experiments,and the effects of the filling ratio and water absorption on the mechanical properties of the materials were analyzed and explained.Finally,the failure modes and mechanism of the hollow glass microspheres composite material were explicated from the microscopic level by scanning electron microscope(SEM).This research will help solve the problems of solid buoyancy materials in ocean engineering applications. 展开更多
关键词 solid buoyancy material water absorption mechanical property failure mechanism scanning electron microscope
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A study on water absorption in freestanding polyurethane films filled with nano-TiO_2 pigments by capacitance measurements 被引量:3
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作者 Mingcheng SUN Fuchun LIU Hongwei SHI Enhou HAN 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2009年第1期27-34,共8页
The electrochemical impedance spectroscopy (EIS) was used to evaluate the water transport and dielectric properties of polyurethane films filled with nano-TiO2 at different pigment/base (P/B) values in 0.5 mol/L N... The electrochemical impedance spectroscopy (EIS) was used to evaluate the water transport and dielectric properties of polyurethane films filled with nano-TiO2 at different pigment/base (P/B) values in 0.5 mol/L NaCl solutions. EIS results were compared with gravimetric measurements on the freestanding films. The amount of water absorption showed great discrepancy between the two methods. The diffusion coefficient in the polyurethane film with P/B:30% was the smallest among those filled with nano-TiO2 pigments. The dielectric constant ε of the polyurethane varnish film obtained from the initial capacitance was in the range of typical values of polymers. SEM was used to measure the distribution of nano-TiO2 particles in the polyurethane films. 展开更多
关键词 water absorption NANO-TIO2 POLYURETHANE EIS
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Influencing factors and mechanism of water absorption process of iron ores during sintering 被引量:2
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作者 Guo-liang Zhang Sheng-li Wu +1 位作者 Juan Zhu Yong-zhi Wang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2014年第2期122-130,共9页
The appropriate content and distribution of sinter moisture play an important role in the granulation of iron ores. In this study, the effects of porosity, size distribution, and particle shape on the water absorption... The appropriate content and distribution of sinter moisture play an important role in the granulation of iron ores. In this study, the effects of porosity, size distribution, and particle shape on the water absorption rate (WAR) of four types of iron ores were analyzed by using the immersion method and capillary water absorption method. In addition, the mechanism underlying the water absorption process in iron ores was unraveled. It is found that the WARs of iron ores decrease quickly with the increase in water absorption time at the initial stages of water absorption. With further increase in absorption time, the WARs decrease gradually, until near 0. Iron ores with higher porosity, smaller particle size, and plate-like structure have the higher WARs. Compared with pores in the single-particle iron ore, voids among particles in the multi-particle iron oxide play an important role at the initial stages of water absorption. The water absorption mechanism of all single-particle and multi-particle iron ores analyzed in this study includes four steps, wherein the first three steps play a significant role in the sintering pro-cess. 展开更多
关键词 iron ores SINTERING water absorption factor analysis
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Water Absorption and Chloride Ion Penetrability of Concrete Damaged by Freeze-thawing and Loading 被引量:1
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作者 杨林 SUN Wei +2 位作者 LIU Cheng 张云升 LIANG Fei 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2017年第2期330-337,共8页
In order to investigate water and chloride ion transport in damaged concrete, three types of concrete were prepared, freeze-thawing(F-T) cycling and compressive loading were adopted to induce damage to concrete. Ult... In order to investigate water and chloride ion transport in damaged concrete, three types of concrete were prepared, freeze-thawing(F-T) cycling and compressive loading were adopted to induce damage to concrete. Ultrasonic pulse velocity technique was used for evaluating the damage degree of concrete, and the defects of damaged concrete were also detected by X-CT. Water absorption and chloride ion penetrability were used for describing the transport properties of damaged concrete. Effects of damage degree on the water absorption rate and chloride ion penetrability were investigated in detail and the relationships were also established. The results show that the water absorption of concrete makes various responses to damage degree due to the difference of concrete type and damage method. For same concrete with similar damage degree, the water absorption rate of F-T damaged concrete is usually larger than that of concrete damaged by loading. The chloride ion penetrability of damaged concrete increases linearly with increasing damage degree, which is more sensitive to damage degree if the original penetrability of sound concrete is higher. 展开更多
关键词 concrete water absorption chloride ion freeze-thawing loading durability
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Application of Air-cooled Blast Furnace Slag Aggregates as Replacement of Natural Aggregates in Cement-based Materials:A Study on Water Absorption Property 被引量:1
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作者 王爱国 liu peng +3 位作者 liu kaiwei li yan zhang gaozhan 孙道胜 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2018年第2期445-451,共7页
The influence of air-cooled blast furnace slag aggregates as replacement of natural aggregates on the water absorption of concrete and mortar was studied, and the mechanism was analyzed. The interface between aggregat... The influence of air-cooled blast furnace slag aggregates as replacement of natural aggregates on the water absorption of concrete and mortar was studied, and the mechanism was analyzed. The interface between aggregate and matrix in concrete was analyzed by using a micro-hardness tester, a laser confocal microscope and a scanning electron microscope with backscattered electron image mode. The pore structure of mortar matrixes under different curing conditions was investigated by mercury intrusion porosimetry. The results showed that when natural aggregates were replaced with air-cooled blast furnace slag aggregates in mortar or concrete, the content of the capillary pore in the mortar matrix was reduced and the interfacial structure between aggregate and matrix was improved, resulting in the lower water absorption of mortar or concrete. Compared to the concrete made with crushed limestone and natural river sand, the initial absorption coefficient, the secondary absorption coefficient and the water absorption capacity through the surface for 7 d of the concrete made from crushed air-cooled blast furnace slag and air-cooled blast furnace slag sand were reduced by 48.9%, 52.8%, and 46.5%, respectively. 展开更多
关键词 air-cooled blast furnace slag aggregate cement-based materials water absorption coefficient interface structure
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Water Absorption Capcapability and Moisture Content Seasonal Changing of Salt-Crust in Lop Nur Dry Lake
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作者 KONG Deyong LI Baoguo +3 位作者 MA Lichun JIANG Ping'an WU Hongqi LIU Hongpeng 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期183-184,共2页
The Lop Nur dry salt lake,Xinjiang province,is charactered by typical physiognomy salt-crust,located in39.6-41.3N.latitude and 89.6-91.4E.longitude.The thickness of salt-crust is about from 20 cm to 100 cm,and
关键词 Lop Nur Dry Lake Salt-Crust Moisture Content water absorption Capcapability
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Characteristics of Water Absorption and the Loss of Dust-Sticking Agent
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作者 Longzhe Jin Thongan Jiang Auiying Jin (Resources Engineering School, University of Science and Technology Beijing, Beijing 10083, China) 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 1999年第1期1-3,共3页
The development of NCZ-1 dust-sticking agent was first intreduced in china. The speed of water absorption of dust-stick-ing agent was measured and studied on mining site and in laboratory, and then the law of water ab... The development of NCZ-1 dust-sticking agent was first intreduced in china. The speed of water absorption of dust-stick-ing agent was measured and studied on mining site and in laboratory, and then the law of water absorption of dust-sticking agent was analyzed. In addition, the mathematical model of the loss rate of dust-sticking agent was established by the application of fluid mechanics theory, and the method of determining the sprinkle parameters of dust-sticking agent was obtained. Through practical verifi-cation, it is found that the error of this mathematical model is less than 10%. So it can be used in the field. 展开更多
关键词 dust-sticking water absorption loss rate mathematical model
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Water Absorption and Degraded Stress Relaxation Behavior in Water-Borne Anticorrosive Urethane/Epoxy Coatings
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作者 Yukitoshi Takeshita Ethan Becker +3 位作者 Seizo Sakata Takuya Kamisho Takashi Miwa Takashi Sawada 《Journal of Chemistry and Chemical Engineering》 2015年第2期75-89,共15页
The kinetics of water absorption in water-borne anticorrosive urethane/epoxy coatings, which were actually introduced in the industrial field, are studied. It is found that the high water affinity of a water-borne coa... The kinetics of water absorption in water-borne anticorrosive urethane/epoxy coatings, which were actually introduced in the industrial field, are studied. It is found that the high water affinity of a water-borne coating supports a higher saturated water content, Mχ, and helps to facilitate absorption D. The three parameters of stretched exponential function called the William-Watt equation, Eo, τ, and β, are determined to fit the degraded stress relaxation behavior in the water absorption process because this function quantitatively describes the relaxing ability and has been successfully used by a number of researchers. An increasing in the water content is shown to correlate strongly with a decrease in Eo and fl early in the absorption process between Mt/M(χ) = 0 and Mt/Mχ≈ 0.5. The adhesive characteristics of the coatings are correlated with water content, and shown to exhibit higher cohesive failure in coating epoxies under saturated conditions. This suggests that water interferes with the intermolecular bonding between polymer chains which degrades the bulk materials ability to diffuse stress concentrations and reduces its overall strength. 展开更多
关键词 water absorption stress relaxation behavior water-borne coating urethane epoxy maxwell model.
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Analysis of Water Absorption of Different Natural Fibers
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作者 Hosne Ara Begum Tanima Rahman Tanni Md Abul Shahid 《Journal of Textile Science and Technology》 2021年第4期152-160,共9页
The demand for natural fibers has always been high due to their unique characteristics like strength, lightweight, availability, bio-degradability, etc. In every phase of life, from clothing to technical textiles, nat... The demand for natural fibers has always been high due to their unique characteristics like strength, lightweight, availability, bio-degradability, etc. In every phase of life, from clothing to technical textiles, natural fibers are used. Water absorption of fibers is considered really important in many aspects, e.g., Sportech, Medtech, Geotech, etc. This work analyses water absorption of raw and alkali-treated cotton, arecas, pineapple leaves, and banana fibers. Fibers were scoured with different concentrations of alkali (2, 4, 6 gm/L NaOH), washed and neutralized with the dilute acetic acid solution, then dried. Later on, the fiber samples were immersed into distilled water, and water absorption percentages of the fibers were determined every 10 minutes within 1 hour in total. It appeared that at untreated conditions, the areca fiber has the highest water absorption capacity compared to the other fibers. Alkali-treated cotton shows the highest water absorption, and areca fibers show approximately 60% water absorption of cotton. 展开更多
关键词 water absorption Alkali Treatment Areca Nut Husk Fiber Pine Apple Leaf Fiber Banana Fiber
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Analytical Methods for Prediction of Water Absorption in Cement-Based Material 被引量:1
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作者 王立成 《China Ocean Engineering》 SCIE EI 2009年第4期719-728,共10页
The capillary absorption of water by unsaturated cement-based material is the main reason of degradation of the structures subjected to an aggressive environment since water often acts as the transporting medium for d... The capillary absorption of water by unsaturated cement-based material is the main reason of degradation of the structures subjected to an aggressive environment since water often acts as the transporting medium for damaging contaminants. It is well known that the capillarity coefficient and sorptivity are two important parameters to characterize the water absorption of porous materials. Generally, the former is used to describe the penetration depth or height of water transport, which must be measured by special and advanced equipment. In contrast, the sorptivity represents the relationship between cumulative volume of water uptake and the squareroot of the elapsed time, which can be easily measured by the gravimetric method in a normal laboratory condition. In the present study, an analytical method is developed to build up a bridge between these two parameters, with the purpose that the sorptivity or the gravimetric method can be used to predict the penetration depth of water absorption. Additionally, a new model to explain the dependence of sorptivity on initial water content of the material is developed in order to fit the in situ condition. The comparison of predicted results by the analytical method with experimental data or numerical calculation results, as well as some previous models, validates the feasibility of the methods presented in this paper. 展开更多
关键词 water absorption capillarity coefficient SORPTIVITY cement-based material initial water content
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Large post-liquefaction deformation of sand:Mechanisms and modeling considering water absorption in shearing and seismic wave conditions
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作者 Jian-Min Zhang Rui Wang 《Underground Space》 SCIE EI CSCD 2024年第5期3-64,共62页
Large deformation of sand due to soil liquefaction is a major cause for seismic damage.In this study,the mechanisms and modeling of large post-liquefaction deformation of sand considering the significant influence of ... Large deformation of sand due to soil liquefaction is a major cause for seismic damage.In this study,the mechanisms and modeling of large post-liquefaction deformation of sand considering the significant influence of water absorption in shearing and seismic wave conditions.Assessment of case histories from past earthquakes and review of existing studies highlight the importance of the two factors.Based on the micro and macro scale mechanisms for post-liquefaction shear deformation,the mechanism for water absorption in shearing after initial liquefaction is revealed.This is aided by novel designed constant water-absorption-rate shear tests.Water absorption in shearing can be classified into three types,including partial water absorption,complete water absorption,and compulsory water absorption.Under the influence of water absorption in shearing,even a strongly dilative sand under naturally drained conditions could experience instability and large shear deformation.The mechanism for amplification of post-liquefaction deformation under surface wave load is also explained via element tests and theoretical analysis.This shows that surface wave–shear wave coupling can induce asymmetrical force and resistance in sand,resulting in asymmetrical accumulation of deformation,which is amplified by liquefaction.A constitutive model,referred to as CycLiq,is formulated to capture the large deformation of sand considering water absorption in shearing and seismic wave conditions,along with its numerical implementation algorithm.The model is comprehensively calibrated based on various types of element tests and validated against centrifuge shaking table tests in the liquefaction experiments and analysis projects(LEAP).The model,along with various numerical analysis methods,is adopted in the successful simulation of water absorption in shearing and Rayleigh wave-shear wave coupling induced large liquefaction deformation.Furthermore,the model is applied to high-performance simulation for large-scale soil-structure interaction in liquefiable ground,including underground structures,dams,quay walls,and offshore wind turbines. 展开更多
关键词 LIQUEFACTION SAND Large deformation water absorption in shearing Surface wave Rayleigh wave-shear wave coupling
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Self-water-absorption-type two-dimensional composite photocatalyst with high-efficiency water absorption and overall water-splitting performance
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作者 Gang Zhao Wenxuan Ma +3 位作者 Xiaoke Wang Yupeng Xing Shuhua Hao Xijin Xu 《Advanced Powder Materials》 2022年第2期9-18,共10页
Photocatalytic overall water splitting is an interesting research topic in the field of energy and outer space exploration.Here,we designed a P/MoS_(2) composite photocatalyst with self-water-absorption performance by... Photocatalytic overall water splitting is an interesting research topic in the field of energy and outer space exploration.Here,we designed a P/MoS_(2) composite photocatalyst with self-water-absorption performance by compositing MoS_(2) nanosheets and polycrystalline black phosphorus nanosheets.The composite photocatalyst produced a sufficient amount of hydrogen in the absence of any precious metal.This also demonstrated photocatalytic overall water-splitting ability in the absence of any sacrificial agent.More interestingly,it effectively absorbed water and demonstrated good overall water-splitting performance under the simulated Mars conditions;the average hydrogen production rate was 17.68μmol h^(-1) g^(-1),and the oxygen production rate was 7.61μmol h^(-1) g^(-1) over a period of 70 h.A comprehensive investigation of the ability of the composite photocatalyst to absorb water and produce hydrogen was performed. 展开更多
关键词 Self-water-absorption-type photocatalyst Two-dimensional materials P/MoS_(2) water absorption Overall water splitting
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Preparation of carbon-based material with high water absorption capacity and its effect on the water retention characteristics of sandy soil
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作者 Youming Yang Mingyang Zhong +2 位作者 Xiuqi Bian Yongjun You Fayong Li 《Biochar》 SCIE CAS CSCD 2023年第1期1057-1074,共18页
Biochar has the potential to provide a multitude of benefits when used in soil remediation and increasing soil organic matter enrichment.Nevertheless,the intricated,hydrophobic pores and groups weaken its water-holdin... Biochar has the potential to provide a multitude of benefits when used in soil remediation and increasing soil organic matter enrichment.Nevertheless,the intricated,hydrophobic pores and groups weaken its water-holding capacity in dry,sandy soils in arid lands.In order to combat this issue,starch-carbon-based material(SB),sodium alginate-carbon-based material(SAB),and chitosan-carbon-based material(CB)have been successfully synthesized through the graft-polymerization of biochar(BC).A series of soil column simulations were used to scrutinize the microstructure of the carbon-based material and explore its water absorption properties and its effects on sandy soil water infiltration,water retention,and aggregation.The results indicated that SB,SAB,and CB achieved water maximum absorption rates of 155,188,and 172 g g^(−1),respectively.Considering their impact on sandy soils,SB,SAB,and CB lengthened infiltration times by 1920,3330,and 3880 min,respectively,whilst enhancing the water retention capabilities of the soil by 18%,25%,and 23%in comparison to solely adding BC.The utilization of these innovative materials notably encouraged the formation of sandy soil aggregates ranging from 2.0 to 0.25 mm,endowing the aggregates with enhanced structural stability.Findings from potting experiments suggested that all three carbonbased materials were conducive to the growth of soybean seeds.Thus,it is evident that the carbon-based materials have been fabricated with success,and they have great potential not only to significantly augment the water retention capacities and structural robustness of sandy soils in arid areas,but also to bolster the development of soil aggregates and crop growth.These materials possess significant application potential for enhancing the quality of sandy soils in arid and semi-arid regions. 展开更多
关键词 BIOCHAR water retention capacity water absorption rate INFILTRATION Soil moisture
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Computer-aided Prediction of the ZrO_2 Nanoparticles' Effects on Tensile Strength and Percentage of Water Absorption of Concrete Specimens 被引量:1
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作者 Ali Nazari Shadi Riahi 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2012年第1期83-96,共14页
In the present paper, two models based on artificial neural networks and genetic programming for predicting split tensile strength and percentage of water absorption of concretes containing ZrO2 nanoparticles have bee... In the present paper, two models based on artificial neural networks and genetic programming for predicting split tensile strength and percentage of water absorption of concretes containing ZrO2 nanoparticles have been developed at different ages of curing. For building these models, training and testing using experimental results for 144 specimens produced with 16 different mixture proportions were conducted. The data used in the multilayer feed forward neural networks models and input variables of genetic programming models were arranged in a format of eight input parameters that cover the cement content, nanoparticle content, aggregate type, water content, the amount of superplasticizer, the type of curing medium, age of curing and number of testing try. According to these input parameters, in the neural networks and genetic programming models, the split tensile strength and percentage of water absorption values of concretes containing ZrO2 nanoparticles were predicted. The training and testing results in the neural network and genetic programming models have shown that two models have strong potential for predicting the split tensile strength and percentage of water absorption values of concretes containing ZrO2 nanoparticles. It has been found that neural network (NN) and gene expression programming (GEP) models will be valid within the ranges of variables. In neural networks model, as the training and testing ended when minimum error norm of network gained, the best results were obtained and in genetic programming model, when 4 genes were selected to construct the model, the best results were acquired. Although neural network have predicted better results, genetic programming is able to predict reasonable values with a simpler method rather than neural network. 展开更多
关键词 Concrete Curing medium Zr02 nanoparticles Artificial neural network Geneticprogramming Split tensile strength Percentage of water absorption
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Finite element analysis and modeling of water absorption by date pits during a soaking process 被引量:1
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作者 Motahareh WAEZI-ZADEH Ahmad GHAZANFARI Shahin NOORBAKHSH 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2010年第7期482-488,共7页
Date pits for feed preparation or oil extraction are soaked in water to soften before milling or extrusion. Knowledge of water absorption by the date pits helps in better managing the soaking duration. In this researc... Date pits for feed preparation or oil extraction are soaked in water to soften before milling or extrusion. Knowledge of water absorption by the date pits helps in better managing the soaking duration. In this research, the process of water absorption by date pits was modeled and analyzed using Fick's second law of diffusion, finite element approach, and Peleg model. The moisture content of the pits reached to its saturation level of 41.5% (wet basis) after 10 d. The estimated coefficient of diffusion was 9.89×10-12 m2/s. The finite element model with a proposed ellipsoid geometry for a single date pit and the analytical model fitted better to the experimental data with R2 of 0.98. The former model slightly overestimated the moisture content of the pits during the initial stages of the soaking and the latter model generally underestimated this variable through the entire stages of soaking process. 展开更多
关键词 Date pits SOAKING water absorption MODELING
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Effect of Water Vapor Absorption on Measurements of Atmospheric Nitrate Radical by LP-DOAS 被引量:3
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作者 Su-wen Li Wen-qing Liu +3 位作者 Pin-hua Xie Yi-jun Yang De-bao Chen Zheng Li 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2008年第5期433-437,共5页
During the measurement of atmospheric nitrate radical by long-path differential optical absorption spectroscopy, water vapor strong absorption could affect the measurement of nitrate radical and detection limits of sy... During the measurement of atmospheric nitrate radical by long-path differential optical absorption spectroscopy, water vapor strong absorption could affect the measurement of nitrate radical and detection limits of system. Under the tropospheric condition, the optical density of water vapor absorption is non-linearly dependent on column density. An effective method was developed to eliminate the effect of water vapor absorption. Reference spectra of water vapor based on the daytime atmospheric absorption spectra, when fitted together with change of cross section with water vapor column densities, gave a more accurate fitting of water vapor absorptions, thus its effect on the measurements of nitrate radical could be restricted to a minimum and detection limits of system reached 3.6 ppt. The modified method was applied during an intensive field campaign in the Pearl River Delta, China. The NO3 concentration in polluted air masses varied from 3.6 ppt to 82.5 ppt with an average level of 23.6±1.8 ppt. 展开更多
关键词 Nitrate radical water vapor absorption Long-path differential optical absorption spectroscopy Detection limit
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DETERMINATION OF ANTIMONY IN WATER SAMPLES BY FLOW-INJECTION HYDRIDE GENERATION ATOMIC ABSORPTION SPECTROMETRY WITH ON-LINE ION-EXCHANGE COLUMN PRECONCENTRATION
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作者 Shu Kun XU and Zhao Lun FANG Institute of Applied Ecology, Academia Sinica, Shenyang, 110015 《Chinese Chemical Letters》 SCIE CAS CSCD 1992年第11期915-918,共4页
On-line ion-exchange separation and preconcentration were combined with flow-injection hydride generation atomic absorption spectrometry (HGAAS) to determine ultra-trace amounts of antimony in water samples. Antimony(... On-line ion-exchange separation and preconcentration were combined with flow-injection hydride generation atomic absorption spectrometry (HGAAS) to determine ultra-trace amounts of antimony in water samples. Antimony(Ⅲ) was preconcentrated on a micro-column packed with CPG-8Q chelating ion-exchanger using time-based sample loading and eluted by 4 mol l^(-1) HCl directly into the hydride generation AAS system. A detection limit (3σ) of 0.0015μg l^(-1) Sb(Ⅲ) was obtained on the basis of a 20 fold enrichment and with a sampling frequency of 60h^(-1). The precision was 1.0% r.s.d.(n=11) at the 0.5μg l^(-1) Sb(Ⅲ) level. Recoveries for the analysis of antimony in tap water, snow water and sea water samples were in the range 97-102%. 展开更多
关键词 Zhang DETERMINATION OF ANTIMONY IN water SAMPLES BY FLOW-INJECTION HYDRIDE GENERATION ATOMIC absorption SPECTROMETRY WITH ON-LINE ION-EXCHANGE COLUMN PRECONCENTRATION SQ CPG ION LINE
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Effect of ocean environmental factors on sound absorption by boric acid relaxation in sea water
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作者 Qiu Xinfang( Received May 17, 1990 accepted August 20, 1990) 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1991年第2期271-280,共10页
By using the expressions for the maximum absorption per wavelength (αλ),and the relaxation frequency fr of the boric acid relaxation derived previously by the author and employing the related oceanographic literatur... By using the expressions for the maximum absorption per wavelength (αλ),and the relaxation frequency fr of the boric acid relaxation derived previously by the author and employing the related oceanographic literatures, the effects of pressure, temperature, pH and salinity on (αλ)r and ∫r of the boric acid relaxation in sea water have been estimated. Results show that ( αλ), not only increases with pH but also increases approximately linearly with pressure and temperature, and is nearly proportional to the 1. 35 power of salinity. However, pressure, pH and salinity have negligible effect on ∫r; therefore, ∫r, can be approximately expressed as a function of temperature only. Comparisons of the predicted with the measured ( αλ)r and ∫r in different ocean areas are given. 展开更多
关键词 Effect of ocean environmental factors on sound absorption by boric acid relaxation in sea water ACID
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