Effects of gravel on the water absorption characteristics and hydraulic parameters of stony soil

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.

Effect of Water Absorption on the Mechanical Property and Failure Mechanism of Hollow Glass Microspheres Composite Epoxy Resin Solid Buoyancy Materials

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.

Synthesis,Characterization and Water Absorption Analysis of Highly Hygroscopic Bio-based Co-polyamides 56/66

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.

Moisture Absorption and Desorption in an Ionomer-Based Encapsulant:A Type of Self-Breathing Encapsulant for CIGS Thin-Film PV Modules

As an alternative to conventional encapsulation concepts for a double glass photovoltaic(PV)module,we introduce an innovative ionomer-based multi-layer encapsulant,by which the application of additional edge sealing to prevent moisture penetration is not required.The spontaneous moisture absorption and desorption of this encapsulant and its raw materials,poly(ethylene-co-acrylic acid)and an ionomer,are analyzed under different climatic conditions in this work.The relative air humidity is thermodynamically the driving force for these inverse processes and determines the corresponding equilibrium moisture content(EMC).Higher air humidity results in a larger EMC.The homogenization of the absorbed water molecules is a diffusion-controlled process,in which temperature plays a dominant role.Nevertheless,the diffusion coefficient at a higher temperature is still relatively low.Hence,under normal climatic conditions for the application of PV modules,we believe that the investigated ionomer-based encapsulant can“breathe”the humidity:During the day,when there is higher relative humidity,it“inhales”(absorbs)moisture and restrains it within the outer edge of the module;then at night,when there is a lower relative humidity,it“exhales”(desorbs)the moisture.In this way,the encapsulant protects the cell from moisture ingress.

Application of Air-cooled Blast Furnace Slag Aggregates as Replacement of Natural Aggregates in Cement-based Materials：A Study on Water Absorption Property

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.

Characteristics of Water Absorption and the Loss of Dust-Sticking Agent

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.

A study on water absorption in freestanding polyurethane films filled with nano-TiO_2 pigments by capacitance measurements

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.

Influencing factors and mechanism of water absorption process of iron ores during sintering

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.

Effect of water absorption ratio on tensile strength of red sandstone and morphological analysis of fracture surfaces

Brazilian disc tests were undertaken on a number of red sandstone samples with different water absorption ratios.The tensile strength of the red sandstone decreases as the water absorption ratio increases.The fracture surfaces of failed red sandstone discs were scanned by Talysurf CLI 2000.With the aid of Talymap Gold software,based on ISO25178,a set of statistical parameters was obtained for the fracture surfaces.The maximum peak height(S_p),maximum pit height(S_v) and maximum height(S_z) of the fracture surfaces exhibited the same decreasing trend with increasing water absorption.Sa and Sku values for the fracture surfaces showed a downward trend as the water absorption ratio increased.The fractal dimensions of fracture surfaces were calculated and found to decrease as the water absorption ratio increased.Through analysis of PSD curves,the smallest dominant wavelength was observed to reflect the roughness of the fracture surfaces.Additionally,the results suggest that the roughness of fracture surfaces becomes small as the water absorption ratio increases.

Analytical Methods for Prediction of Water Absorption in Cement-Based Material

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.

Effect of Soaking Temperature on Water Absorption Characteristics of Selected Ghanaian Cowpea Varieties

The water absorption kinetics of three cowpea varieties (Asontem, Hewale and Asomdwee) was studied following the phenomenological models derived from Fick’s law of diffusion. Soaking of seeds from each cowpea variety was carried out for 10 h at four temperatures (30°C, 40°C, 50°C and 60°C). The saturation moisture content was higher for Asontem (106.9 g water/1000 g dry weight) and Hewale varieties (108.7 g water/1000 g dry weight) and lower for Asomdwee hybrid (100.7 g water/1000 g dry weight), respectively. The proposed Fick’s law of diffusion satisfactorily described the kinetics of water absorption regardless of the variety and temperature. The estimated values for water diffusion coefficient for Asontem, Hewale and Asomdwee varied from 5.12 × 10-10 m2/s to 6.64 × 10-10 m2/s, 3.96 × 10-10 m2/s to 5.12 × 10-10 m2/s, 4.93 × 10-10 m2/s to 6.08 × 10-10 m2/s, respectively. The strong influence of temperature on the water diffusion coefficient was adequately described by an Arrhenius-type equation with activation energy values for Asontem, Hewale and Asomdwee as 7.27 kJ/mol, 7.26 kJ/mol and 6.26 kJ/mol, respectively.

The Effect of Water Absorption on Mechanical Properties of Wood Flour/Wheat Husk Polypropylene Hybrid Composites

The main objectives of this research were to study the effect of water absorption on mechanical properties of hybrid fiber reinforcement for polypropylene composites. The poor resistance towards water absorption is one of the draw- backs of natural fibers. Hybrid filler-polypropylene composites are subjected to water immersion tests in order to study the effects of water absorption on the mechanical properties. Composites specimens containing 30 phr and 40 phr fiber weight were prepared by melt blending process. Water absorption tests were conducted by immersion specimens in distilled water at room temperature for different time durations (24, 48, 72, 96, 120, 144, 168, 192 hours). The tensile, flexural and impact properties were investigated before and after water absorption. The percentage of moisture uptake increased as the increasing order of the filler loading due to the high cellulose content. The phase morphology of wood flour/wheat husk polypropylene hybrid composites were investigated by SEM, the dynamic mechanical properties of the composite are analyzed by DMA & wheat, wood filler interaction are analyzed by FT-IR.

Zeolite A enhanced chitosan films with high water absorption ability and antimicrobial activity

Zeolite A/CS xerogel hybrid films were prepared by in-situ crystallization method with uniform structure and good strength.The hybrid films prepared from the precursor films dried at 50℃showed zeolite A was well crystallized.The hybrid films show high water absorption,good elastic strength and Young modulus.The antimicrobial ability of the hybrid films was investigated after Ag^(+)-ion exchanged.The Ag^(+)-exchanged hybrid films with 35%(mass)content of zeolite A showed the highest antimicrobial activity,which could reduce the concentration of the microbial to zero after 7 h.

An Artificial Neural Network (ANN) Model for Predicting Water Absorption of Nanoclay-Epoxy Composites

Glass fiber reinforced epoxy (GFRE) composite materials are prone to suffer from water absorption due to their heterogeneous structure. The main process governing water absorption is diffusion of water molecules through the epoxy matrix. However, hydrolytic degradation may also take place during components service life specially due high temperatures. In order to mitigate the effects of the water diffusive processes in the deterioration of in-service behavior of epoxy matrix composites, the use of chemically modified nanoclays as an additive has been proposed and studied in previous works [1]. In this work, an Artificial Neural Network (ANN) model was developed for better understanding and predicting the influence of modified and unmodified bentonite addition on the water absorption behavior of epoxy-anhydride systems. An excellent correlation between model and experimental data was found. The ANN model allowed the identification of critical points like the precise temperature at which a particular system’s water uptake goes beyond a predefined threshold, or which system will resist an immersion longer than a particular time.

An Evaluation of the Water Absorption and Density Properties of Expanded Polystyrene Sanded Concrete

In this paper, the evaluation of the mechanical and hygro-thermal properties of expanded polystyrene-sanded lightweight concrete (EPSLC) was examined. Evaluated are the mechanical properties in terms of density;and the hygro-thermal property using water absorption (capillary absorption and total immersion) as measures. The research used 30% volume of EPS to replace natural coarse aggregate to produce a lightweight concrete, which is expected to be economical, serviceable and meet the required standards for lightweight concretes. The concrete bulk and oven dry densities were obtained as 1789 KN/m3 and 1674 kg/m3 respectively, while the total water and capillary water absorption increases with time of suction. The high rate of water absorption at the early periods of the test has corresponding capillary coefficient of steep slope within the same period. The relationship between the variables Q the water absorption per unit area of the specimen and K the capillary coefficient, is that as the water absorption gets higher, so does the capillary coefficient and the percentage of the variation is expressed by the correlation coefficient R2. Therefore, the values of R2 as depicted in the graphs shows a high percentage of variation. The moisture capacity is 6.9%. All the laboratory tests were, conducted in accordance with standard codes of practice. The significance of the research is that innovative technology is employed to modify and improve processes in construction industry, thus, enhancing sustainable environmental, management of industrial waste, and cheaper and economic construction. With the 30% replacement of coarse aggregate, the density and water absorption properties of concrete produced are within acceptable limits. Therefore, EPS can be used to produce lightweight concrete that will perform the required function at this level of replacement.

Analysis of Water Absorption of Different Natural Fibers

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.

Large post-liquefaction deformation of sand:Mechanisms and modeling considering water absorption in shearing and seismic wave conditions

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.

Preparation of carbon-based material with high water absorption capacity and its effect on the water retention characteristics of sandy soil

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.

Computer-aided Prediction of the ZrO_2 Nanoparticles' Effects on Tensile Strength and Percentage of Water Absorption of Concrete Specimens

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.

Water Absorption and Chloride Ion Penetrability of Concrete Damaged by Freeze-thawing and Loading

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.