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Accurate knowledge of hydraulic properties of unsaturated soil is vital to modelling water and solute transport process and addressing soil salinisation problems. Due to the defect that the van Genuchten (VG) model cannot represent soil water characteristics (SWC) during the drying stage, we have introduced a modified model, which combines capillary flow with film flow models to describe the unsaturated hydraulic conductivity. The capillary SWC is obtained by assuming the specific water capacity function with lognormal distribution. The film SWC is modified using the logarithmic nonlinear expression by introducing a modification coefficient into the Campbell equation, and the film relative hydraulic conductivity (RHC) is obtained based on the logarithmic nonlinear relationship. The calculated modification coefficient values range from 0.99 to 2.49. Finally, the proposed model's rationality and applicability are validated through root mean square error (RMSE) analysis with measured values and comparison with the VG model. While the calculation RMSEs of SWC in the two models are basically consistent, the RMSEs of RHC in the proposed model are around 1–10 times smaller than those of the VG model, indicating its superiority in calculating the hydraulic conductivities over the entire matric head. Highlights: A modified model describing the variably saturated hydraulic conductivity is presented combining the capillary with film flow model. A logarithmic nonlinear expression with a modification coefficient is introduced in the film soil water characteristic model. The fitting parameters for relative hydraulic conductivity are determined and root mean square errors are chosen for evaluating the modified model. [ABSTRACT FROM AUTHOR]

The physical meaning of the neutral stress and effective stress for soils is still unclear, which leads to the neutral stress for unsaturated soils being totally ignored and increasingly complicated expressions for effective stress. To solve these problems, we establish an extended three-phase physical model for unsaturated soils, including capillary water, pore air, and generalized soil skeleton (GSS) and then derive a generalized Terzaghi's effective stress equation, stating that the effective stress is equal to total stress minus neutral stress. In our equation, the neutral stress consists of three components, i.e. the homogenized pore fluid pressure, the stress acting on the cross sections of soil particles, and the stress acting on the contacts between particles. The mechanical effects of the neutral stress can be appreciable, especially in unsaturated clays at a relatively low saturation. The effective stress is found to be the stress that is transmitted through GSS. The local stress, induced by physicochemical forces, cementation, and surface tension, is not transmitted through GSS, and thus, it should not be added into effective stress equation. The mechanical effects of the effective stress are controlled by the mechanical parameters of GSS expressed as a function of suction besides the effective stress itself. Integrating the mechanical effects of neutral stress and effective stress, a general framework is proposed for describing the mechanical behaviour of unsaturated soils. Under the framework, the proposed shear strength equation is in very good agreement with the experiment data reported in the literature. [ABSTRACT FROM AUTHOR]

As to the roadbed projects in coastal areas, capillary water rise can produce roadbed diseases and affect the safety and durability of road operation. It is important to study the capillary water rise height. The article regards capillary water rise as a kind of unsaturated soil seepage phenomenon, and introduces fractal dimension to unsaturated soil permeability coefficient modification. A capillary water rise height model based on fractal theory is proposed to obtain the capillary water rise height curve with time. Then a vertical tube method capillary water rise height test was conducted on a mainline roadbed soil sample in Nantong, with the control test of changes in the dry density of the soil sample and the fractal dimension of the initial particle size distribution. The results show that: the capillary water rise presents a rapid increase at the beginning, and then slowly increases, and finally stabilizes. The larger the fractal dimension of the particle size distribution of soil sample, the greater the capillary water rise height; the smaller the dry density of the soil sample, that is, the greater the porosity, the greater the capillary water rise height. In the capillary water rise height model, the capillary water rise height is related to the sample porosity, saturated permeability coefficient, capillary water rise height corresponding to the inlet value, fractal dimension, etc. In the theoretical model, the variation of fractal dimension only changes the capillary water height corresponding to the inlet value, not the saturated permeability coefficient; while the dry density change, i.e., the porosity change, only leads to the saturated permeability coefficient change, does not affect the intake value corresponding to the height of capillary water, the results from theoretical model are consistent with those from the test, verifying the effectiveness of the theoretical model. This study provides theoretical guidance for the prevention and control of road-base capillary water disease.

Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The purpose of this experiment was to explore the influence of different cooking temperatures on the deterioration characteristics of pork batter gel by using proteomics, gel electrophoresis, size and chemical bond of aggregates. The results showed that the protein molecules of the pork batter gel was degraded during heating cooking and the protein aggregates were composed of many degraded protein fragments; compared with the control group 75 °C (0 min), the significant degradation of cytoskeleton showed at 110 °C (30 min) and 121 °C (30 min) and the significant degradation of myosin complexonly appeared at 121 °C (30 min). As the heating temperature points increased, compared with the control group 75 °C (0 min), the different temperatures could promote the separation of metal ions with proteins especially at 110 °C (30 min) and 121 °C (30 min), which could ultimately influence quality of pork batter gel by the size of particle. As the increase of heating temperature points, the recombination of aggregates composed of different proteins was not conducive to the retention of capillary water, which reduced the texture of pork batter gel. This research provided theoretical support for improving the process property of the meat products.

To investigate unsaturated soil-water interaction at micro-scale, this study extends the numerical manifold method (NMM) by incorporating a soil-water coupling model considering specific capillary water distribution and capillary force calculation. The soil skeleton is constructed by a soil skeleton generation algorithm with random polygons. To more realistically capture the interaction between soil grains and capillary water, a capillary mechanics-based geometric algorithm is proposed to iteratively calculate the capillary water distribution. The capillary forces corresponding to the capillary water distribution are calculated based on the Young-Laplace equation. The proposed capillary water solving framework is first verified by reproducing the soil-water characteristic curve and the capillary water distribution of an ideal contact-disk model against analytical solutions. To further validate the ability of the capillary water solving framework to predict hydraulic behavior of the real soil, a laboratory test on the Toyoura sand is reproduced numerically. Then an ideal direct shear test is performed to further validate the two-way soil-water coupling procedure, in which a comparison between the numerical and analytical results regarding the shear strength and matric suction is presented. Finally, microscopic hydraulic and compression tests are conducted on two soil specimens with the same porosity and mean grain diameter but different uniformity coefficients. The results elucidate that the extended method is a potential tool to explore unsaturated soil behaviors at micro-scale.

The soil freezing characteristic curve (SFCC) represents the constitutive relationship between sub‐zero temperature and unfrozen water content in soil. It governs the hydrologic and mechanical behaviors associated with freezing soil. Numerous studies have investigated the mechanisms of soil water freezing and attempted to predict SFCC using soil water characteristic curve (SWCC) and Clapeyron equation. However, limited attention has been given to the physical disparities between adsorbed and capillary water during freezing, including variations in pressures and water‐ice interfaces. In this study, we present a novel theoretical model for predicting SFCC. The model determines the freezing point by calculating the chemical potential of soil water and ice with their respective pressures, thus capturing the distinctions in freezing behaviors between adsorbed and capillary water. All model parameters possess clear physical interpretations, and the model solely relies on the SWCC as input. The validity of the proposed model was confirmed through experimental measurements involving the water phase diagram, SWCCs, and the corresponding SFCCs of sandy, silty, and clayey soils. The model exhibits strong capabilities in predicting SFCC regardless of the soil type and outperforms the conventional method in predicting the SFCC of soil with high adsorbed water content. Model analyses were performed to investigate the effects of individual pore size, soil type, and initial water content on the freezing process, revealing the distinct contributions of adsorption and capillarity in soil water freezing. This study elucidates the mechanisms underlying soil water freezing, offering a theoretical framework for the analysis and prediction of frozen soil behaviors. Plain Language Summary: The freezing point of soil water is lower than that of free water, and the relationship between sub‐zero temperature and unfrozen water content is soil freezing characteristic curve (SFCC). The unfrozen water content is important for the physical processes in soil. Soil water content comprises adsorbed water and capillary water. They are retained in soil by different physical mechanisms, that is, adsorption and capillarity. As a result, they exhibit distinct freezing behaviors. However, the freezing of adsorbed water has been overlooked in many studies. This work established a theoretical SFCC model based on the chemical potential equilibrium between pore water and ice. The model can describe the freezing of adsorbed and capillary water and only requires the soil water characteristic curve (SWCC) as input. Experimental water phase diagram, SFCCs, and SWCCs validated this model. The model can predict the SFCC of various soils and is superior to the conventional method in predicting the SFCC of soils with high adsorbed water content. The clear physical mechanism in the model enables the analysis of the effects of pore sizes, soil types, and initial water content on unfrozen water content. This work provides a useful tool to predict frozen soil behaviors. Key Points: A theoretical soil freezing characteristic curve (SFCC) model considering the physical disparities between adsorbed and capillary water is establishedThe model exhibits advantages in predicting the SFCC of soils with high adsorbed water contentThe model can illustrate the effects of soil types and initial water contents on SFCC [ABSTRACT FROM AUTHOR]

Alaboratory experiment was carried out during 2020 in the laboratories of the College of Agriculture / University of Anbar in order to study the role of phosphogypsum in the values ​​of saturated hydraulic conductivity, capillary height and water holding capacity of soil in clay soil. The phosphogypsum was added mixed with the soil at four levels (without adding, 0.3%, 0.6% and 0.9%) by weight of the soil. The treatments were incubated for 90 days by adding water at the limits of the field capacity and compensation the lost water after deplete 50% of the available water. The amount of available water, the saturated hydraulic conductivity, and the capillary height has been estimated. The soil water holding capacity increased significantly, which was 16.91% at the addition of 0.9% compared to the treatment without addition. While the highest value of the saturated hydraulic conductivity was 0.35 cm per hour -1at the level of 0.9% addition. The capillary height decreased significantly with the increase in the level of phosphogypsum addition, and the lowest value was 52 cm when adding 0.9%.

A soil water unit weight of 9.8 kN/m3 has been universally considered to quantify soil volumetric phase properties such as void ratio and degree of saturation, but has been found to greatly vary depending on soil type and the volume scale with which it is defined. Recent experimental and theoretical evidence has indicated that the unit weight of soil water can be significantly greater than 9.8 kN/m3 for clayey soils when gravimetric water content is less than 30%. A soil water unit weight as high as 18.8 kN/m3 is evident for some expansive soils at low water content. The significance of abnormally high water unit weight in quantifying soil phase volumes, saturation, and void ratio was experimentally assessed for various clayey soils and theoretically interpreted as a function of water content and soil type. For clayey soils with low liquid limit, average soil water unit weight can be as high as 12.5 kN/m3 for gravimetric water content less than 10%. This leads to an overestimation of liquid-phase saturation and void ratio by as much as 8% if a soil water unit weight of 9.8 kN/m3 is used. For clayey soil with a high liquid limit, the average soil water unit weight can be as high as 18.8 kN/m3 for water content less than 18%, leading to overestimation of liquid-phase saturation by as much as 36% and void ratio by as much as 20% if 9.8 kN/m3 is used. Charts were developed to estimate average soil water unit weight as a function of soil specific surface area and water content, and as a function of liquid limit and water content. The commonly used value of 9.8 kN/m3 for water unit weight can lead to significant errors in estimating phase volumes, void ratio, and saturation for clayey soils. [ABSTRACT FROM AUTHOR]

Solar desalination is one of the most promising ways to produce freshwater. Interfacial solar steam generation system is especially studied for its high solar–thermal conversion efficiency. However, the phase transition process of water evaporation is energy intensive and a salt cluster is easily accumulated at the surface of the evaporator, which limits the water yield and stability of the distiller. Herein, a hybrid design involving tuning the water state, recycling latent heat, and spatial localizing low‐concentration zone to distill for stable and efficient solar‐water harvesting is demonstrated. In a two‐stage distiller, the water yield can reach 1.62 kg m−2 h−1 under one sun irradiation, corresponding to the solar‐to‐vapor conversion efficiency of 110%. The scale‐up device can also steadily operate for 1 week outdoors. This work provides an effective strategy for high‐efficiency solar distillation, holding the promise of application in seawater desalination and domestic water supply. [ABSTRACT FROM AUTHOR]

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Dafo Bay stone carvings in Baoding Mountain, Dazu District, Chongqing City, are suffering from serious capillary water damage, salt damage, biological and other derivative diseases caused by capillary water, which have brought a long-term negative effect on the protection of the world cultural heritage. Based on the field investigation of the Dafo Bay, the strata of the statuary cliff are divided into three sets: the upper sandstone of the reclining Buddha, the sandstone of the reclining Buddha and the lower sandstone of the reclining Buddha. Through a series of tests and experimental studies, the characteristics of sandstone in the Baoding Mountain area and the influence of temperature and humidity on capillary water are analyzed.The testing items include thin section identification, X-ray diffraction, chemical composition test, scanning electron microscopy, mercury injection test, Karsten tube penetration test, etc.The research results indicated that: compared with the upper and lower layers of the reclining Buddha sandstone, the Reclining Buddha body sandstone has the lowest maturity and the largest porosity and pore distribution range, which provides relatively good conditions for the migration of capillary water. The capillary water absorbability and capillary water elevation of the reclining Buddha body sandstone are the best, and the rise of capillary wateris closely related to the ambient temperature, relative humidity, and air circulation. In the tight sandstone of the Dazu Stone Carvings, a large number of interconnected micropores cannot play a role in the migration of capillary water. The effective pore diameter for capillary water migration in the reclining Buddha sandstone should be above 1 133.0 nm, and may reach 760.2 nm in extreme cases.The research results provide reliable data for an accurate understanding of the formation and evolution of capillary water in Dazu Stone Carvings, explain the formation mechanism of salt damage in Dazu Stone Carvings in winter, and provide a theoretical basis for managing capillary water in Dazu Stone Carvings.

Using numerical method to investigate the evolution of micro-structure in unsaturated soil is helpful to explain their physical mechanical. However, the evolution of micro-structure in unsaturated soil is not clear. For this reason, the capillary method is proposed to simulate compression test of unsaturated soil for analyzing soil-water interaction and evolution of pore spaces. In this research, an ideal micro-structure soil model of 540 μm×400 μm is established according to the shape and size of skeleton particles of loess. The capillary method is used to calculate the capillary water distribution and capillary force under different water content(5%, 10%, 18%), and the force then acts on the wetting surface among particles. The loading is applied to the soil sample. The compression test of unsaturated soil is simulated in this research. The simulation results show that the characteristics of compression curve are in good agreement with the experiment data, indicating that the numerical test can reflect the unsaturated soil deformation behavior under the condition of compress. Moreover, the saturation increases and matric suction decreases with the compression of the soil; the saturation increases most at high water content; the matric suction decreases least at middle water content; the deformation pattern is related with the moisture, namely, the pores are mainly shrunk at low water content while mainly disintegrated at high water content. The simulation results are a very useful supplement to laboratory test to explore the deformation mechanism of unsaturated soil.

The mechanical behavior of loess is highly predicated on variation in its moisture content. While the impacts of the water content on the shearing behavior and collapsibility of loess have been extensively studied, its effect on tensile characteristics has received relatively little attention. In this study, a series of tensile tests were conducted on remolded specimens of a clayey loess that were collected from Ili Valley in China. Two sets of loess specimens with varying water contents were prepared separately using wetting and drying methods. The influence of the water content on the tensile stress–strain response, failure mode and tensile strength was investigated by combining the tensile test results and particle image velocimetry (PIV) analysis. On this basis, a nuclear magnetic resonance (NMR) test and scanning electron microscopy (SEM) observations were implemented in order to assist with the interpretation of the underlying mechanism. The test results indicate that the tensile failure process and the variation of tensile strength with varying water contents differ for specimens that are prepared with wetting and drying methods; a finding which arises from the differences in the soil microstructure, clay–water interaction and the distribution of capillary and adsorbed water. This research has shown that the tensile strength of clayey loess is essentially dominated by the clay's hydration/cementation and the development of capillary and adsorption suction as well as the microstructural evolution that occurs with the change in the water content. Based on the experimental observations, a conceptual model is proposed in order to interpret the effect of water content on loess' tensile behavior. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Anbar Journal of Agricultural Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

During road construction, soils are often compacted at the optimum water content to achieve maximum dry density and best performance. After construction is completed, the soil water content in the field will inevitably increase with time due to capillary rise, rainfall infiltration, and other factors. Conventional drainage systems rely on geomaterials or geosynthetics with large pores to drain gravity (or free) water but cannot drain out capillary water. The excess water in the road system causes pavement deterioration under repetitive traffic load. Recently, two new types of geosynthetics were used as drainage materials. However, most of the field tests were inconclusive due to complicated site conditions and soil nonuniformity. The relative performances of these drainage geosynthetics and their working mechanisms were largely unclear. In this study, laboratory tests were conducted to quantify the cumulative amount of water drained under different drainage situations. The volumetric water content of soils was monitored by moisture sensors and the water contents of soils under different drainage situations were evaluated and compared. Finally, the working mechanisms of different drainage materials were discussed. [ABSTRACT FROM AUTHOR]

Immediately after casting, the occurrence of early age shrinkage is sensitive to internal stresses, degree of hydration, and tensile strength, which is of concern to engineers. This study investigated the influences of wind speeds on early‐age shrinkage and tensile strength (strain) of cement paste, and the results were further interpreted by an investigation of hydration degree and capillary water. The outcomes show that as the wind speed increased, the shrinkages (i.e., drying, chemical, and autogenous shrinkage) experienced various trends depending on several factors. Meanwhile, a variety of wind speeds altered the proportion of the evaporation in the capillary water, the inner moisture distribution, and the humidity difference between specimens' surface and their interior sections. Further, tensile strength and elastic modulus were deteriorated by wind, whereas with the growth of the wind speed, the ultimate tensile strain of specimens exhibited various scenarios within and after 24 h. [ABSTRACT FROM AUTHOR]

The purpose of this experiment was to explore the influence of different cooking temperatures on the deterioration characteristics of pork batter gel by using proteomics, gel electrophoresis, size and chemical bond of aggregates. The results showed that the protein molecules of the pork batter gel was degraded during heating cooking and the protein aggregates were composed of many degraded protein fragments; compared with the control group 75 °C (0 min), the significant degradation of cytoskeleton showed at 110 °C (30 min) and 121 °C (30 min) and the significant degradation of myosin complexonly appeared at 121 °C (30 min). As the heating temperature points increased, compared with the control group 75 °C (0 min), the different temperatures could promote the separation of metal ions with proteins especially at 110 °C (30 min) and 121 °C (30 min), which could ultimately influence quality of pork batter gel by the size of particle. As the increase of heating temperature points, the recombination of aggregates composed of different proteins was not conducive to the retention of capillary water, which reduced the texture of pork batter gel. This research provided theoretical support for improving the process property of the meat products., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 Published by Elsevier Ltd.)

Silt has the characteristics of capillary pore development and strong water sensitivity. The rise of capillary water in silt may cause the strength of the roadbed to decrease or instability. It is vital to identify the mechanical and engineering properties of silt roadbed under capillary water. In this paper, a typical silt in Nantong of Jiangsu Province was selected to investigate the variation rules of the cohesion c, the internal friction angle φ, and the compression modulus Es under different water content by quick direct shear test and compression test. Furthermore, based on the test results, the engineering characteristics of low embankment under capillary water were studied by numerical simulation. The results show that the saturation Sr had little effect on the φ but had an obvious effect on the c. The c of silt decreased with the increase of the Sr. With the increase of water content w, the Es of silt showed a strong nonlinearity. When the void ratio e was larger, the w was the main factor affecting Es. However, the experimental results have a certain applicability, that is, the form of water and gas in the silt was in the stage of "internal connectivity of gas phase." In the case of the same groundwater level, when the filling was low, the deformation of the subgrade was obviously affected by capillary water. According to the simulation results, it is preliminarily determined that the reasonable filling height of silt low embankment was between 1.2 and 1.5 m. [ABSTRACT FROM AUTHOR]

According to the characteristics of capillary water and membrane water in the pores, this article, based on the basic principles of fluid dynamics and thermodynamics, established the pore boundary and freezing law of capillary water and membrane water through literature reading and data statistics. The analysis of the research results shows that the frozen macropores generate suction at the curved ice-water interface, which drives the capillary water and film water in the unfrozen pores to migrate inside the frozen macropores. The freezing process can be divided into three stages: supercooling, rapid decline, and stable. However, there are only stable and fast melting stages in the melting process, and there is no overheating corresponding to the supercooling phenomenon. According to the low-field-NMR test of the silt during the freezing process, the boundary between capillary water and film water was proved, and the correctness of the capillary-film water migration model and migration path was verified. [ABSTRACT FROM AUTHOR]

Formulation of an effective stress equation for unsaturated soils where all relevant physical characteristics are included has challenged researchers for several decades. On one hand, the interfacial forces and the contractile skin have recently been understood to be of significant contribution to the effective stress, particularly at low degrees of saturation. On the other hand, the microstructural effects play a significant role, especially in fine-grained soils. In this study, an equation is proposed for the effective stress parameter (χ ) based on the recent advances in modeling the adsorbed water, and thereby determining the capillary water retention curves. In the proposed relationship, both the microstructural effect and interfacial forces are taken into account. Additionally, in formulating effective stress, these two aforementioned aspects have been considered and formulated for both drying and wetting conditions. To this end, the interfacial forces were determined based on the capillary water content. Next, the proposed model was further simplified to reduce the number of unknown parameters to one with the rest of the parameters readily available from the soil water retention curve. The simplified formulation agrees fairly well when compared with the experimental data on soils experiencing both drying and wetting paths. Furthermore, assessing the performance of the proposed model, compared with the available equations incorporating the contribution of the interfacial forces, indicates the superiority of the proposed model for the eight soil types examined in this study. [ABSTRACT FROM AUTHOR]

The mechanical behavior of loess is highly predicated on variation in its moisture content. While the impacts of the water content on the shearing behavior and collapsibility of loess have been extensively studied, its effect on tensile characteristics has received relatively little attention. In this study, a series of tensile tests were conducted on remolded specimens of a clayey loess that were collected from Ili Valley in China. Two sets of loess specimens with varying water contents were prepared separately using wetting and drying methods. The influence of the water content on the tensile stress–strain response, failure mode and tensile strength was investigated by combining the tensile test results and particle image velocimetry (PIV) analysis. On this basis, a nuclear magnetic resonance (NMR) test and scanning electron microscopy (SEM) observations were implemented in order to assist with the interpretation of the underlying mechanism. The test results indicate that the tensile failure process and the variation of tensile strength with varying water contents differ for specimens that are prepared with wetting and drying methods; a finding which arises from the differences in the soil microstructure, clay–water interaction and the distribution of capillary and adsorbed water. This research has shown that the tensile strength of clayey loess is essentially dominated by the clay’s hydration/cementation and the development of capillary and adsorption suction as well as the microstructural evolution that occurs with the change in the water content. Based on the experimental observations, a conceptual model is proposed in order to interpret the effect of water content on loess’ tensile behavior.

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the hydrologic cycle, sandy soils play the role of a connecting reservoir of surface water and groundwater, particularly in arid areas. Therefore, to provide water conservation and ecological environment protection, it is important to study the soil water behavior in the unsaturated zone. At present, the CT-scan method is commonly used to study the soil hydraulic properties. In the field of materials science, the industrial CT high-resolution instruments are applied for quantitative research on the porous microstructure and fluid filtration law in sandy soils. In this study, we have studied five samples of sand scans of the quartz sand and CUGB coarse sand types. The industrial-type CT instrument XTH225ST was used for the sample microstructure scanning. In order to identify water: air, and solid particle distribution of the sample cross section, and to analyze the particle size distribution and moisture content, the scanned images were processed using the VG-Studio and ImageJ software. Comparing the CT-scan results of the four quartz sand samples, it can be concluded that the optimal particle size, ranges from 1 to 2 mm. According to the porosity quantitative analysis, with decrease in the particle size, the total porosity grate soil sample increases. After applying the image recognition and VG- Studio software, we can see that for different particle sizes of the sand sample, the average pore size increases with increase in the particle size. To study the moisture absorption and desorption phenomenon, two samples of the CUGB coarse sand are experimentally studied. The particle size of the samples range: from 1 to 2 mm. The CT scanning analysis is used to obtain the unsaturated characteristic curve of the soil when the moisture content reaches stability. Due to the lag phenomenon, the characteristic curve of the soil moisture has an obvious "loop," or hysteresis, shape. As shown by a 3D modeling, the distribution of capillary water in the sand column is complex, and the water flow forms multiple winding paths, like "worms" creeping in the soil. The CT-scan method is used to overcome the limitations of the traditional experimental methods and to evaluate the relationship between the moisture content and the matrix suction. The obtained characteristic curve of soil moisture can be used to improve the efficiency of technological operations. The CT-scan method provides a new way of evaluating the water distribution characteristics of unsaturated soil. [ABSTRACT FROM AUTHOR]

Capillary water is the main cause of freezing damage and collapsible damage of compacted loess. Therefore, researching capillary water migration law of compacted loess is the key to solve various damage in the infrastructure construction of loess. Different regions have different climatic conditions, which make the physical and mechanical properties of the loess is different. In order to reveal the capillary water migration law of compacted loess in Ningxia, the moisture migration law of compacted loess with different degrees of compaction was studied by using standpipe method. The results show that the migration rate of capillary water is rapid at the early stage and gradually became slower with the increase of time, which is negatively related to the degree of compaction and migration height. The maximum migration height of capillary water increases exponentially with the increase of compactness. Migration rate and migration height of capillary water are related to capillary water potential, gravitational potential, and pipe-resistance of capillary. In this study, the relational equation can predict capillary water distribution and the migration height of compacted loess was newly established. This equation can also provide a reference to reduce various damage and freeze-thaw effect in compacted loess. [ABSTRACT FROM AUTHOR]

The natural vegetation in arid areas of northwest China is strongly dependent on the availability of groundwater. Significantly, capillary water plays an essential role in regulating the ecological groundwater level in the multilayered structure of the vadose zone. The soil-column test and field survey in the lower reaches of the Shiyang River Basin were conducted to investigate the influence of the multi-layered structure of the vadose zone on maintaining the ecological effect of groundwater. Based on the field survey, the results show that the depth of groundwater is 3.0 m, and the rising height of capillary water is 140 cm. In the soil-column test, the height of the wetting front of the column was 125 cm. During the water releasing test, the water held by the vadose zone was 182.54 mm, which would have maintained Haloxylon’s survival in a growing season. Therefore, the multi-layered structure of the vadose zone extends the ecological groundwater depth and consequently enhances the ecological function of groundwater. Importantly, with a lower groundwater level, the clay soil layer within the rising height range of the original capillary water would hold more water and maintain a higher water content for a certain period to supply surface vegetation.

Many shallow foundations are constructed within the soil layer above the groundwater table, where the soil remains unsaturated, and the failure of shallow foundation is mostly related to shear failure. The shear strength of the unsaturated soil is one of the main engineering properties required in geotechnical designs. Previous researchers suggested that the shear strength of the unsaturated soil depends on matric suction in the soil. The shape of the soil–water characteristic curve (SWCC) has a significant effect on the characteristics of unsaturated shear strength with respect to matric suction. In this paper, a new model was proposed for the estimation of the unsaturated shear strength from SWCC. In this new model, meniscus was considered to transfer soil suction into both additional net normal stress and additional cohesion. Based on the categorization from soil science, water in soil can be categorized into three groups: (1) gravity water, (2) capillary water and (3) hygroscopic water. The elemental analysis on the contractile skin indicated that only the capillary water in the soil can transfer stress into soil skeleton. Consequently, the SWCC is modified by considering capillary water only for the estimation of unsaturated shear strength. In the derivation, unsaturated soil is considered as four-phase material. Finally, a new mathematical equation for the estimation of the unsaturated shear strength was proposed and verified with the experimental data from the published literature. In addition, the proposed equation does not consist of any empirical parameter and can be used to predict the shear strength of unsaturated soil. [ABSTRACT FROM AUTHOR]

Solid-state fermentation (SSF) has regained interest owing to its advantages in solid waste treatment and fermentation industries. However, heterogeneous heat and mass transfer are often caused by the absence of free water and noticeable water loss from microbial utilization and moisture evaporation in SSF. It is necessary to explore more effective ways to solve issues of water loss and water supplement in SSF based on online capillary water monitoring, because capillary water is the dominant form of water that is present and lost in substrate. Two novel capillary-water supply strategies were proposed, established and evaluated using three selected reference strains, including water-retention materials and negative-pressure auto-controlled irrigation (NPACI). This study employed superabsorbent polymer, a kind of water-retention material to enhance enzyme productivity with the most significant increase of 2.47 times. Moreover, the combination of NPACI and 0.1% superabsorbent polymers increased productivity by 2.80-fold, together with lowered gradients of temperature, moisture and products. Furthermore, a modified liquid-supply SSF was constructed through successful capillary water control by proposed humidity control strategies. This modified SSF system could address the shortcomings of inhomogeneous culture of traditional SSF.

Highlights • Coupling effect of mechanical load and environment load had influence on the durability performance of concrete structure. • Water and chloride penetration into concrete decreased firstly and then increased with the increase of applied load. • Applied load had an obvious influence on the frost resistance of concrete. • Coupling effect had more obvious influence on high water/ratio concrete. Abstract In cold coastal area, the destruction mechanism of reinforced concrete structures is mainly governed by a combination of factors such as self-loading, freeze–thaw and chloride erosion. In this study, ordinary cube concretes (C30 and C50, while w/c = 0.53 and 0.35 respectively) underwent a coupling effect of pressure load with stress ratio of 0, 0.3 and 0.5 and freeze–thaw cycles, following by capillary water absorption test and chloride penetration test. Concrete samples with 0.3 f c showed the best water and chloride penetration resistance under the coupling effect, followed by samples with 0.5 f c and 0 f c , which is consistent with the conclusion that under load only. Water and chloride ions penetration increased sharply when freeze–thaw cycles was over 100 times, which is different with samples without load. Outside part of concrete showed higher permeability and chloride content than inside part. MIP results confirmed that stress played an important role in the water absorption and chloride penetration of concrete under the coupling effect. These results provide important new insights into the permeability of concrete under a coupling effect. The applied load performed a more important role on the service life prediction of concrete structure. [ABSTRACT FROM AUTHOR]

Purpose: Bound water has a large impact on physical and chemical properties of clay. The objective of this study was to investigate the contents, types, and physical properties of bound water and provide insights for understanding the thermal behavior and hydration process of the marine mucky silty clay under the control of bound water. Materials and methods: An integrated approach incorporating isothermal adsorption, thermogravimetric analysis (TGA), and specific gravity testing were developed to determine the contents and the boundaries of different types of bound water in Qingdao clay and investigate their physical characteristics. Results and discussion: Adsorption isotherm can be divided into two phases, which are the formation of strongly bound water and some capillary water under condition of p/ps < 0.9 and the formation of weakly bound water in the coverage for p/ps > 0.9. The initial dehydration temperatures of strongly bound water range between 87 and 92 °C in the hydrated clays under condition of p/ps < 0.98. Weakly bound water starts to be released at temperatures near 60 °C and is completely removed at temperatures between 90 and 108 °C. Capillary water and free water are evaporated before 60 °C. The specific gravity of hydrated clay decreases linearly with adsorbed water contents. The volume of hydrated clay, volume of adsorbed water, and thickness of water film approximately linearly increase with adsorbed water contents. Conclusions: Quantitative determination and classification for bound water can be implemented through thermogravimetry (TG) and derivative thermogravimetry (DTG) curves. The physical properties of hydrated clay and bound water film are directly affected by the adsorbed water contents. The results may contribute to environmental and engineering risk assessment. [ABSTRACT FROM AUTHOR]

Abstract Soil salinization impacts millions of hectares of land around the world and threatens many soil ecosystem services. Impacts of soil salinization are long lasting and impact agriculture productivity, reduce plant diversity and cause increase soil erosion due a reduction or loss in surface vegetation. Generally, remediation of saline soil relies on soil washing methods and phytoremediation to translocate salts below the rooting depth of plants. However, standard methods can often be unsuccessful as leached salts are able to return to the rooting zone through subsequent capillary rise in the soil. Surface application of iron (III) ferrocyanide has been used to remediate salt contaminated soil as the ferrocyanide complex induces salts to efflorescence at the soil surface as water evaporates rather than crystallising within the soil matrix. However, surface application of iron (III) ferrocyanide tends to be less successful in clay textured soil and does not work well when subsequent reapplications of water are made for further salt removal. In this study we investigate a biomimetic approach to desalinate soil by mimicking the capillary transport mechanisms employed by vascular plants. Our approach uses evapotranspiration to translocate saline soil water above the soil surface where it is effloresced with ferrocyanides. After 30 days of treatment, the biomimetic approach used 2.1 pore volume equivalents of water and was able to reduce the concentration of salts from 8% (g·NaCl/g·soil) to 0.8% (g·NaCl/g·soil), resulting in a reduction of soil EC from 120 mS/cm to 14 mS/cm. Our findings indicate that the method, with further refinement and expansion to field based trials, could be an effective tool to desalinate soil and reduce global soil salinization. Graphical abstract Unlabelled Image Highlights • Biomimicry of evaporative hydrostatic pressure and capillarity in vascular plants facilitated remediation of saline soil. • A 10 fold reduction in soil EC (120 mS/cm to 14 mS/cm) was achieved in 30 days. • Our approach may be a viable alternative to traditional methods for the remediation of saline soil. [ABSTRACT FROM AUTHOR]

Different types of soil water, such as bound water and capillary water, have distinct effects on the physicochemical and engineering properties of soils, particularly unsaturated clayey soils. Therefore, it is crucial to develop an accurate and physically meaningful experimental method for identifying and quantifying these components. This study pioneers the use of a multi-step kinetic model to identify and quantify different soil water components across a wide range of relative humidity (RH) using thermogravimetric analysis (TGA) data. To validate the determined kinetic parameters (i.e., activation energy, preexponential factor, and reaction model) and the identification and quantification results of soil water components, TGA with multiple heating rates, nitrogen adsorption method, cation exchange capacity measurement, and nuclear magnetic resonance (NMR) were performed on kaolin samples equilibrated under various RH conditions. These experimental results cross-validate the superior performance of the kinetic model in determining soil water components and predicting the thermal desorption behaviors of soil water. Based on the cross-validation results, the soil water components obtained from the kinetic analysis are further identified as tightly-bound, loosely-bound, and capillary water, which exhibit variations consistent with empirical soil water isotherm models. The T 2 cutoff value between bound and capillary water is determined to be 1.79 ms based on TGA and NMR results. The determined thermal kinetic parameters of different soil water components can exhibit their distinct retention mechanisms. The method and results in this study provide a new perspective on identifying different soil water components, as well as understanding the mechanism of soil-water interactions in unsaturated soils. • A method based on thermogravimetric and kinetic analysis is developed to identify and quantify soil water components. • Kinetic model can detect tightly-bound, loosely-bound, and capillary water in kaolin. • Different soil water components exhibit distinct kinetic triplets. • Bound water content increases with humidity regardless of capillary condensation. • NMR T 2 cutoff value between bound and capillary water is 1.79 ms. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Uranine visualizes vaporization plane within porous media by color changes. • This novel method is widely applicable both in the laboratory and field. • The method visualizes complex-shaped vaporization plane in hydrophobic materials. • Temporal changes of vaporization plane can be studied to some degree. Abstract The vaporization plane in porous media separates the region of capillary flow from the dry surface layer, where the water transports only in its gas phase. Knowledge of the depth and geometry of the vaporization plane is critical for estimating water flux in the soil-atmosphere interphase, for understanding evaporating processes in general, and for prediction of locations of damaging salt crystallization, etc. However, detection of the vaporization plane is a challenging task. This paper explores the use of sodium fluorescein dye (uranine), a popular hydrological tracer, to visualize the vaporization plane in porous media. Uranine was used in the forms of solution or powder on sand, sandstone, and autoclaved aerated concrete, in both laboratory and field experiments. The property of uranine solution to change its color according to its concentration can be used to: i) visualize the vaporization plane by forming a distinctive dark-orange zone where the pore water evaporates, and ii) to distinguish the zone of vapor flow from the zone where capillary flow is present. Similarly, uranine powder, when applied onto a porous material, clearly visualizes the dry surface layer and the capillary zone, divided by the vaporization plane. This technique can also visualize a complex-shaped vaporization plane in hydrophobic materials. In comparison with other techniques, such as sensible heat balance or heat pulse methods, the use of uranine is accurate, cost-effective, and straightforward. [ABSTRACT FROM AUTHOR]

A new unfrozen water characteristics curve (UWCC) model is proposed with explicit considerations of both capillarity and adsorption. Capillarity is considered to be dominant when the freezing of soil pore water occurs at higher temperatures, whereas the effects of adsorption are pronounced at lower temperatures. The proposed model is applied to predict UWCCs of silt at different initial void ratios and clay over a wide range of temperatures. It was found that the new model can capture the effects of void ratio on the UWCC. Moreover, the new model can better predict the UWCC over a wide range of temperatures. [ABSTRACT FROM AUTHOR]

A physical calculation model for the content of unfrozen water of silty clay was proposed with a consideration of freezing point. The freezing point of bulk water, capillary water and bound water was calculated. The freezing point of bulk water was assumed to be constant in the calculation. The Kelvin equation and the theory of water activity were used to calculate the freezing-point changes of the capillary and bound water during the volume decrease, respectively. The influence of soil-particle size on the freezing point was taken into account in the model. In the calculation, the unfrozen water content at a negative temperature was defined as the sum of the volume of capillary and bound water whose freezing point was lower than the given temperature. By using silty clay from the Qinghai-Tibet Plateau as an example, the results of the model calculations were validated by using the measured data from time-domain reflection and nuclear magnetic resonance. The calculations for four existing models as proposed by other scholars were listed for comparison with our model. The results show that the calculated results of our model are precise and reflect the hysteresis effect of the unfrozen water content during freezing and thawing. The model validated an order of freezing in soil: bulk water froze first, most capillary water froze next, and most bound water froze last. This paper explains the existence of unfrozen water from the perspective of freezing-point change and provides a theoretical basis for the calculation. [ABSTRACT FROM AUTHOR]

• A theoretical SFCC model for saline soil is proposed and validated. • The unfrozen water content during two phase transition stages is well predicted. • Eutectic temperature is related to the initial solute concentration and saturation. Soil freezing characteristic curve (SFCC) characterizes the relationship between liquid water content and temperature in frozen soils, which is of significance in simulating the heat, moisture, and solute migration process in the hydrological cycle in cold regions. Soil freezing process of saline soils includes various stages including ice or salt crystallization and ice-salt eutectic. However, most SFCC models ignored the eutectic stage. Based on the framework of chemical potential equilibrium, a theoretical model is developed considering the ice-salt eutectic phenomenon in this study. The model can well predict the change in unfrozen water content in various stages for both low and high initial concentrations from the soil–water characteristic curve (SWCC). The applicability and accuracy of the model are well verified by the published data of the measured phase diagrams of bulk salt solution and SFCCs for different types of soils. The effects of soil type, initial solute concentration, and initial water content on soil freezing process and eutectic temperature are further analyzed using the theoretical model, which is in agreement with reported experimental results. The work provides a comprehensive view to understand the freezing characteristic of saline soils. [ABSTRACT FROM AUTHOR]