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The estimation of mechanical and physical properties of coal reservoirs is important for the successful exploration and development of coalbed methane (CBM). Unlike conventional sandstone reservoirs, coal reservoirs exhibit greater sensitivity to stress, resulting in distinct mechanical and physical behaviors. In this study, uniaxial compression tests were performed on both low-rank and high-rank coal samples under different moisture conditions to reveal the mechanical and physical property changes with stress. The results indicate that during axial stress loading (up to 2.8 MPa), axial strain initially increases rapidly and subsequently at a slower rate, with an axial strain of 0.13–0.25% observed at the maximum axial stress. The instantaneous Young's modulus increases linearly before stabilizing, ranging from 618.01 to 4861.10 MPa, while the Poisson's ratio remains relatively constant or increases linearly, ranging from 0.002 to 0.165. This results in a negative exponential decrease in both porosity and permeability, with maximum reductions of 1.77–4.21% and 5.38–12.25%, respectively. The mechanical properties of coal are influenced by both the cementation effect of water at low water saturation and the softening effect at high water saturation, which results in axial strain decreases and then increases as the water saturation increases. Concurrently, the elastic modulus initially increases and then decreases, while the Poisson's ratio exhibits a less pronounced change or tends to increase. Consequently, there is a trend in which porosity and permeability first increase and then decrease. In addition, during stress unloading, the influence of water in coal induces a notable strain hysteresis phenomenon in water-containing coal samples, and this phenomenon is more obvious in the low-rank coals. [ABSTRACT FROM AUTHOR]

Red clay exhibits characteristics such as softening owing to water absorption and cracking because of water loss, which can lead to slope instability, road cracking, and compromised structural integrity when used directly in roadbed filling. Although the addition of industrial materials such as cement is a common engineering treatment, it severely impairs soil renewability. Lignosulfonate (LS) extracted from paper plant waste fluids is a natural bio-based polymer with promising applications as a soil improver. In this study, the boundary moisture content and mechanical properties of LS-treated red clay were investigated using Atterberg, unconfined compressive strength, and direct shear strength tests. Additionally, the LS-treated red clay modification mechanism was explored at multiple scales using zeta potential analysis, X-ray diffraction, scanning electron microscopy coupled with energy dispersive spectroscopy, and Fourier transform infrared spectroscopy. The results indicated that the LS dosage significantly affected both the water content and mechanical strength of the red clay boundaries. The optimal dosage of LS for red clay was 3 wt. %, at which the liquid limit was reduced by 32.97%, the plastic limit by 19.33%, and the plasticity index by 48.37%. The 28-day compressive strength of LS-treated red clay was increased by 378.4%, and the direct shear strength was increased by 136%. Analysis of the microstructure and mineral composition revealed that the LS-treated red clay did not form new minerals, but primarily filled pores and connected soil particles. Through the combined effects of hydrogen bonds, electrostatic interactions, and cation exchange, the LS-treated red clay reduced the size of the mineral particles and the thickness of the mineral double electric layer, resulting in increased structural densification. These results are of great scientific significance for the ecological modification of soils. [ABSTRACT FROM AUTHOR]

Ultrasonication deployment provides a green and non‐thermal option to traditional hydrothermal treatment. This study presents the impact of ultrasonication and soaking temperatures (30 and 50°C) on the water uptake and hardness of two cowpea types under increasing soaking times (15–240 min). Moisture content and hardness of the studied samples were measured using standard test methods and instruments. An increase in soaking temperature and the use of ultrasonication enhanced water uptake and reduced hardness. Ultrasonication improved mass transfer, which enhanced the diffusion of water uptake. The samples' water uptake and softening characteristics were significantly modeled with high accuracy (R2 = 0.99) using sigmoidal and first‐order kinetics equations, respectively. The impact of sonication was found to be more significant at 30°C soaking of the studied cowpeas as the soaking time increased. This work justified using ultrasonication as a green technique to enhance the softening of cowpeas. [ABSTRACT FROM AUTHOR]

The current state of the hydrosphere is largely determined by human anthropogenic activities. Discharge of polluted waste waters into surface water bodies significantly worsens their quality and limits the possibility of safe consumption. One of the biggest sources of increasing surface waters mineralization and hardness is the discharge of spent regeneration solutions of natural waters ion-exchange softening processes, which creates a closed circulation cycle of sodium, calcium and magnesium chlorides. The necessity to reduce the intensity of this cycle and decrease environmental pollution is very actually today. The research of traditional soda-sodium softening technology has shown its low suitability for low and medium capacity systems due to necessity of water heating and subsequently pH adjusting. More acceptable solution was found in using phosphate anions as a precipitant, which ensures high efficiency in removing calcium and magnesium ions at a wide range of temperatures and pH levels. It was found that the solid phase formed during such treatment was difficult to separate from the liquid phase. Using of anionic flocculants was proposed as one of the solutions of this problem, which ensure high efficiency in separating the formed solid particles from water. Proposed technological scheme was designed for implementation as a pre-treatment stage in reverse osmosis systems of low and medium capacity. [ABSTRACT FROM AUTHOR]

When heated rapidly, glasses often devitrify heterogeneously, i.e., by a softening front that originates at the surface of an amorphous film. Yet the fundamentals of this devitrification regime are not completely understood; depending on experimental conditions, the reported front propagation distances differ by an order of magnitude. Using a high-resolution fast scanning calorimetry technique, we have investigated the softening of glassy methylbenzene films with thicknesses between 30 and 1400 nm. We confirm first that, in all films, the devitrification process begins with the formation of a softening front that propagates through the films over distances of ∼50 nm and that the front propagation kinetics at this stage follow an Arrhenius law. However, we also show that, in films with thicknesses above 165 nm, the front propagation does not terminate with the onset of bulk softening. Specifically, increasing the films' thicknesses above 165 nm yields sharp, clearly discernible endotherms that precede the bulk softening endotherms and that are consistent with a two-fold increase in the enthalpic barrier to front propagation at a well-defined critical temperature. We term this phenomenon "Arrhenius discontinuity" and use reaction rate and continuum front dynamics theories to explain its origins and the physical nature of the resulting distinct heterogeneous devitrification processes. Finally, we discuss the findings in the context of recent theoretical, computational, and experimental studies of heterogeneous devitrification by other research groups. [ABSTRACT FROM AUTHOR]

In order to solve the problems of frequent electrode cleaning and low efficiency in electrochemical descaling, a new electrochemical water softening reactor with horizontal electrodes was developed. In the new electrochemical water softening reactor, the inflow flowed horizontally through the cathodic chamber and then the anodic chamber. The movement of water and bubbles promoted OH- diffusion and strengthened the homogeneous nucleation of CaCO3. By optimizing current density, flow rate and initial hardness, the homogeneous nucleation was strengthened. At the flow rate of 2.7 L/h, the current density of 80 A/m2 and the influent hardness of 400 mg/L, the softening efficiency was achieved as 155 g/(h·m2), hardness removal was 150 mg/L, current efficiency was 50% and energy consumption was 15 kW·h/g. With these performance, cathodic cleaning frequency was reduced effectively.

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To study the formation mechanism of rainfall‐induced soil erosion, collapse and landslides in the Loess Plateau based on the unsaturated soil seepage theory and the effective stress principle, the failure process of collapse with cracks under heavy and long‐term rainfall was investigated using the finite element method. The results showed that under the action of heavy rain, surface run‐off quickly gathered in cracks to form a dominant flow, resulting in a rapid increase in the water level and hydrostatic pressure in the cracks. The strength of the soil at the tip of the crack decreased rapidly under the softening effect of the water, and tensile failure occurred. The crack accelerated downward to the foot of the slope, causing the steep slope to collapse. Long‐term rainfall acts directly on the soil near the crack, resulting in faster saturation than the soil inside the slope body. When the rainfall time exceeded a certain value, the soil near the crack reached a saturated state, and the soil strength was minimized. Simultaneously, the seepage force generated when rainwater inside the collapsed body seeps from its outer edge increases the overturning moment of the collapsed body. Under the continuous action of rainfall, the cracks gradually extended to the foot of the slope, causing the collapsed body to fail. These research results provide a theoretical basis for the prevention and control of land degradation and collapse disasters on the Loess Plateau. [ABSTRACT FROM AUTHOR]

This article discusses the importance of water pretreatment for businesses that rely on equipment such as steamers, hot water heaters, coffee makers, and ice machines. It explains that water hardness, caused by calcium and magnesium ions, can lead to scale formation and inefficient operation of equipment. The article introduces various anti-scale technologies, including ion-exchange resins and phosphate/polyphosphates, as well as a new media blend that has shown promising results in controlling scale buildup and corrosion. The document includes a test conducted in Henderson, NV, comparing different anti-scale media, with Media 3 performing the best. Overall, the study emphasizes the significance of addressing scale issues in water treatment to prevent equipment problems. [Extracted from the article]

AbstractFor rock structures exposed in the natural condition, water-induced weakening (including water softening and chemical weathering) is thought to be the main reason for its’ stiffness and strength degradation, thus it is of great significance to study the mechanical properties of rocks under the influence of water. In this study, a hexagonal close-packed particle assembly (2D) composed of bonded circular particles with same diameter is considered to approximate a typical soft rock, where the composite contact model for rock materials considering the water-induced wakening is adopted to define the microscopic mechanical reactions between particles. Based on homogenisation theory and lattice model, the stress-strain relationship and strength criteria for rock considering water-induced weakening, as well as the quantitative correlation between macroscopic elastic and strength parameters with microscopic parameters are obtained. The effects of water softening and chemical weathering respectively characterised by saturation and mass loss ratio on macroscopic mechanical behaviours of rock are analysed in detail. The long-term ageing effects of water-induced weakening are also analysed. All results are in good agreement with the laboratory test results, verifying the applicability of the theoretical solution for analysing the effect of water-induced weakening on mechanical behaviours of rock. [ABSTRACT FROM AUTHOR]

Water softening is a treatment process required to manage calcium and magnesium cations in water streams. Moreover, detection of such cations in water samples using simple portable techniques is required for monitoring and inspection of water quality. Nanocomposites can provide solutions for such multiple challenges while showing high performance and cost-effectiveness. In this work, the Cu-Fe layered double hydroxides (LDH)/cysteine-based electrodes were synthesized and are used as active materials for the electrochemical detection of calcium ions. The electrode materials were characterized using XRD, FTIR, and SEM. The synthesized electrode showed a limit of detection and a limit of quantification of 0.21 µM and 0.73 µM, respectively. The concentration range of detection was 5–30 µM. The intermolecular interactions of Ca ions with cysteine-free LDH and cysteine-LDH were investigated by Monte Carlo and molecular dynamics simulations. Monte Carlo simulations revealed that the (001) surface is favored for Ca(II) adsorption within the LDH structure with an energy of adsorption equals to 372.46 kcal/mol. This work paves the road towards developing cost-effective disposable electrode based on portable electrochemical detection of Ca ions for on-site water softening applications. [ABSTRACT FROM AUTHOR]

Electrodialysis (ED) and the continuous evolution of ion exchange membranes are one of the reasons behind its diverse applications. Known to be a high-water recovery process with limited uses of chemicals gives it the advantage of sustainable treatment technology. Water softening plays a major role in water industry; it can ensure clean, safe, and efficient water use but it affects water equilibrium. Mainly the lack of calcium carbonate causes a real issue in water distribution networks made of concrete, pipes, and reservoirs by decreasing their lifetime. This paper addresses the selectivity of softening using ED to reduce the negative impact of water hardness and to maintain both the quality and equilibrium of water. This latter should be neither too hard nor too soft, and the calco-carbonic equilibrium is of major interest. In this work, ED operations were carried out at a laboratory scale using different water initial concentrations. The propensity of the water towards calcium carbonate scaling was addressed by monitoring the Langelier saturation index (LSI) generally used to assess water scaling potential. At a demineralization rate (DR) of 80%, all the dilutes obtained from all the feed water reached the status of soft water. ED gave good results in terms of hardness reduction, and LSI corresponded to the equilibrium state at a DR of 40% in all the cases studied. [ABSTRACT FROM AUTHOR]

Loess has unique water sensitivity due to its distinct formation environment. The structure of loess is undercompactness, weak cementation, and porousness. The water sensitivity of loess directly leads to many environmental problems and geological hazards, including subgrade subsidences, slope collapse or failures, and building cracking. To reveal the relationship between water sensitivity and loess structure, confined-compression collapsibility tests and triaxial-collapsibility tests were performed on loess in different areas. The collapsibility coefficient, porosity ratio, and collapsibility rate were analyzed. Results show that the collapsibility process of loess can be divided into three stages: wetting, softening, and settling. The collapsibility sensitivity of loess is determined primarily by its structural and hydraulic state. [ABSTRACT FROM AUTHOR]

The mechanical soft–hard transition of hydrogels is desired in conditions‐adaptive deformation and mechanics reconfiguration applications. However, highly efficient, stimuli‐responsive, and reversible transition strategies are hard to achieve. Inspired by the supercooling of salt‐aqueous solutions, solid and supersaturated hydrogels are prepared based on a hydrophilic polymer network and salt‐aqueous solution. The inner crystallization‐ or melting‐induced reversible phase‐change realizes the switch between the soft hydrogel (modulus: 0.1 MPa) and rigid composite (modulus: 24.0 MPa). The soft and supersaturated hydrogels easily deform to achieve diverse new 3D models and the unfamiliar soft–hard transition makes temporary shapes be efficiently fixed (hardening). Interestingly, the initial hydrogel's shapes can be regenerated relying on the resilience of the polyacrylamide network when the crystal is melted (softening). Shape memory, complex surface morphology replication, rapid mold application, and self‐supporting laminated glass are accomplished by this unique crystallization‐melting introduced soft–hard transition. This phase change soft‐hard switching strategy will broaden the functionalities of hydrogels. [ABSTRACT FROM AUTHOR]

In this article, the methods of cleaning and disinfection of drinking water in livestock farms are discussed. In order to choose the appropriate cleaning method, first an analysis is made of the water that will be used for irrigation and then the necessary processing is selected - filters, water softening, reverse osmosis, additional mineralization, disinfection by means of UV sterilizers. On the basis of the cost rate for irrigation of dairy cows, the necessary cleaning agents with the most effective capacity are indicated. By observing certain water parameters, the health and quality of life of animals in small and large farms is guaranteed. [ABSTRACT FROM AUTHOR]

To investigate the characteristics of crack propagation and microscopic structure under water–rock coupling effect in deep surrounding rock, a triaxial mechanical experiment was conducted on sandstone strata in the Shandong Wanfu Coal Mine under the action of pressurized water absorption. The experimental results showed that the mass increment of the rock sample was exponentially related to the confining pressure, and the mathematical relationship curve of the mechanical strength variation of the rock sample under different confining pressures was obtained. Based on this, the strength softening formula of the rock sample with the absorption time under different confining pressures was obtained, and the softening process was divided into three stages: the relatively stable stage, the rapid softening stage and the deceleration softening stage. The T2 spectrum curve of the rock sample was normalized, and the pore distribution and strength softening curve under different confining pressures were constructed. The speed of water molecules entering pores in different softening stages was analyzed, and it was found that in the relatively stable stage, the speed was micro-pore > meso-pore > macro-pore, in the rapid softening stage, the speed was meso-pore > macro-pore > micro-pore, and in the deceleration softening stage, the speed was micro-pore ≈ meso-pore ≈ macro-pore. According to the law of microscopic pore structure changes under water–rock coupling, a pore structure model of sandstone under different confining pressures was constructed. Based on the crack propagation model and crack propagation rate formula, it was concluded that the increase in crack strain propagation rate was the result of both water saturation and permeation water pressure, and a distribution map of the crack strain propagation rate was established. By comparing the crack strain propagation rate, it was found that under the same characteristic stress, the axial strain propagation rate of the crack was greater than the radial strain propagation rate, and the radial strain propagation rate was greater than the volume strain propagation rate. Quantitative relationships between crack propagation in sandstone and water saturation under different stress conditions were obtained. [ABSTRACT FROM AUTHOR]

Soft rocks are prone to softening upon contact with water, and their rapid deterioration in mechanical properties is a significant cause of instability and failure soft rock masses. Besides, the macroscopic mechanical response of rocks is closely related to the mineral composition and microstructure. The purpose of this research is to consider the heterogeneity factors and softening effects, and systematically investigate the influence of confining pressure and softening time on the damage and failure characteristics of soft rocks. The Voronoi polygons generated using a built-in Voronoi diagram algorithm and contact elements (the substances with cementing capacity) of UDEC discrete element method are employed to represent the clastic grains and interfacial cemented bonding (ICB) structures in soft rock. Based on the Voronoi probabilistic method, the grain-based discrete element model (GB-DEM) considering the softening effect is established by introducing a meso-scale softening damage factor, along with a detailed calibration method for meso-scale parameters. The damage parameters such as the crack initiation threshold, the crack damage threshold, the damage degree, and the tensile and shear crack ratio are then analyzed. The study results indicate that the simulated strengths of the heterogeneous models under different water immersion time are in good agreement with the experimental results. The thresholds for crack initiation and damage, the proportions of tensile and shear cracks, and the degree of damage are positively correlated with the confining pressure. The attenuation patterns of the crack initiation threshold and damage threshold in the heterogeneous models with water immersion time are highly consistent with the meso-scale softening damage factor. The damage parameters show a trend of increasing first and then decreasing with the extension of water immersion time. The cement–cement contact elements are the main locations for crack initiation and propagation. The research outcomes have significant theoretical and practical implications for understanding and predicting the mechanical behavior of soft rocks under a water–rock interaction. [ABSTRACT FROM AUTHOR]

In the Tunnel Boring Machines (TBMs) construction of soft rock tunnels, adverse geological conditions, such as water-rich and wet strata are often encountered. Water in strata can change the stress state and weaken the mechanical performance of rock mass, further affecting the tunneling process and rock breaking efficiency. To study the effect of water content on mudstone fragmentation characteristics and cutter force during TBM cutter indentation, the water softening effect is considered in the moisture diffusion-fracture coupling model based on the finite-discrete element method (FDEM). Then, the micro parameters (fracture energy release rate, swelling coefficient and moisture diffusion coefficient) of mudstone are calibrated by uniaxial, triaxial compression and swelling tests. Subsequently, the water content and swelling deformation evolution of mudstone samples during water migration are revealed. Finally, the coupling model is utilized to investigate the fragmentation characteristics and cutter force of mudstone samples with different water contents under various confining pressures during TBM cutter indentation. The fragmentation zone, cutter force, acoustic emission (AE), and crack number during cutter indentation are quantitatively analyzed. Results indicate that the vertical extent of fragmentation range (Ev) decreases with the increase of water content, while the horizontal extent of fragmentation zone (Eh) does not decrease obviously until the water content reaches 3%. The increase of confining pressure reduces the effect of water content on Ev, and the increase of water content also reduces the effect of confining pressure on Ev, indicating that confining pressure and water content have a mutual inhibition effect on Ev. Besides, both the peak value of normal force and the fluctuation range of tangential force for the TBM cutter decrease with the increase of the water content. The AE counts show that the failure pattern of mudstone is mainly shear failure during TBM cutter indentation. Specifically, many shear cracks are generated in the compression zone under the cutter, while few tensile cracks propagate in mudstone on both sides and deeper below the cutter. For mudstone under different confining pressures, the proportion of shear cracks increases with the increase of water content. Moreover, the effect of cutter penetration velocity on mudstone fragmentation characteristics and cutter force is discussed. The results in this paper have theoretical guidance for TBM construction of soft rock tunnels in water-rich and wet strata. Highlights: A FDEM moisture diffusion-fracture coupling model is first applied to study the effect of water content on rock fragmentation by TBM cutter. Shear failure is the main failure pattern of mudstone during TBM cutter indentation. The fragmentation zone and cutter force are greatly affected by water content during TBM cutter indentation. Water content and confining pressure have a mutual inhibition effect on the vertical extent of fragmentation zone. [ABSTRACT FROM AUTHOR]

A new type of bio-composite material is being produced from water-recovered resources such as cellulose fibres from wastewater, calcite from the drinking water softening process, and grass and reed from waterboard sites. These raw materials may be contaminated with pathogens and chemicals such as Escherichia coli, heavy metals, and resin compounds. A novel risk assessment framework is proposed here, addressing human health risks during the production of new bio-composite materials. The developed framework consists of a combination of existing risk assessment methods and is based on three main steps: hazard identification, qualitative risk mapping, and quantitative risk assessment. The HAZOP and Event Tree Analysis methodologies were used for hazard identification and risk mapping stages. Then, human health risks were quantitatively assessed using quantitative chemical risk assessment, evaluating cancer and non-cancer risk, and quantitative microbial risk assessment. The deterministic and the stochastic approaches were performed for this purpose. The contamination of raw materials may pose human health concerns, resulting in cancer risk above the threshold. Microbial risk is also above the safety threshold. Additional analysis would be significant as future research to better assess the microbial risk in biocomposite production. The framework has been effectively used for chemical and microbial risk assessment. [ABSTRACT FROM AUTHOR]

A plastic injection waste known as "purge" cannot be reintegrated into the recycling chain due to its shape, size, and composition. Grinding these cannot be carried out with traditional mills due to significant variations in size and shape. This work proposes a process and the design of a device that operates with solar energy to cut the purges without exceeding the degradation temperature. The size reduction allows reprocessing, revalorization, and handling. The purges are mixtures of processed polymers, so their characterization information is unavailable. Some characterizations were conducted before the design of the process and after the cut of the purges. Some of the most representative purges in a recycling company were evaluated. The flame test determines that all material mixtures retain thermoplasticity. The hardness (Shore D) presented changes in four of the purges being assessed, with results in a range of 59–71 before softening and 60–68 after softening. Young's modulus was analyzed by the impulse excitation technique (IET), which was 2.38–3.95 GPa before softening and 1.7–4.28 after softening. The feasibility of cutting purges at their softening temperature was evaluated. This was achieved in all the purges evaluated at 250–280 °C. FTIR allowed for corroboration of no significant change in the purges after softening. The five types of purges evaluated were polypropylene-ABS, polycarbonate-ABS-polypropylene, yellow nylon 66, acetal, and black nylon 66 with fillers, and all were easily cut at their softening temperature, allowing their manipulation in subsequent process steps. [ABSTRACT FROM AUTHOR]

Water hardness significantly impacts water quality, influencing both industrial processes and daily domestic applications. This study investigates the efficacy of electrodialysis (ED) in removing hardness, aiming for a balanced approach that avoids aggressive or scaling tendencies. Response surface methodology (RSM) was employed to determine the interaction between the inputs and the hardness removal, optimizing key parameters using the Box-Behnken design (BBD). The resulting regression model, validated through analysis of variance (ANOVA), demonstrated a high R² value of 0.9761 and an adjusted R² value of 0.9454, indicating a robust fitness for hardness removal prediction. The interaction of both voltage and initial concentration holds significance in our investigative study. A notable hardness removal efficiency of 87% was achieved at a demineralization time of 47 min, an applied voltage of 11V and an initial concentration of 5.3 mmol/L. This research enhances our understanding of critical operating parameters in ED, offering insights for optimizing the process toward effective water softening and long-term water treatment. [ABSTRACT FROM AUTHOR]

The strong mine pressure disaster easily induced by the high stress concentration area of deep coal seam bifurcation and merging area (CSBMA). Zhangshuanglou Coal Mine was selected as the research site. Theoretical analysis, physical and numerical simulation and field measurement was adopted to study the evolution law and control technology of mining-induced stress in the deep CSBMA. The main conclusions are as follows: (1) from the bifurcation area to the merging area, the peak value of the front abutment pressure decreases first and then increases slightly to a stable evolution law with the gradual decrease of the coal seam spacing. From the merging area to the bifurcation area is the opposite. (2) The coal seam spacing of the bifurcation area is 7.5–25 m, which is the area where the peak value of the front abutment pressure increases. The maximum peak value is located at the junction of the normal area and the bifurcation area, and the stress concentration coefficient is about 2.1. (3) After the control technology of coal seam water injection softening is adopted for the high stress concentration area, the maximum peak stress concentration coefficient is reduced to about 1.6, which effectively reduces the stress concentration degree. The evolution law of mining-induced stress in the deep CSBMA provides guidance for the prevention and control area of strong mine pressure disaster in this area, and ensures the safe mining of working face. [ABSTRACT FROM AUTHOR]

The seepage effect of rock and soil in the process of encountering water follows a nonlinear coupling law between water and rock. According to the permeability of rock and soil during softening with water, changes in particles in rock and soil are related to permeability mechanisms. Based on the assumption of connection between particles in rock and soil, changes in particles before and after water infiltration, the mechanism of water–rock interaction, and the damage to rock and soil are analyzed herein. Combined with fractal theory and percolation theory, the random failure characteristics and nonlinear behavior of water in rock and soil are studied. At the same time, with the help of Fluent 17.0 software, the seepage process of rock samples in water is numerically simulated and analyzed. Taking the permeability coefficient of rock samples, the mass flow rate of water, and the internal pore water pressure of rock samples as tracking objects, it is found that there are obvious nonlinear characteristics in the process of water–rock interaction. The seepage–stress coupling between water and rock forms negative resistance to water seepage. The water infiltration is a slow and then accelerated process and tends to be stable. Research has shown that the coupling effect of seepage between water and rock increases the damage inside the rock and soil, and its permeability fluctuates randomly at different time steps. This feature is a common manifestation of fractal properties and percolation within rock and soil particles. At the same time, there is a non-equilibrium variation law of pore water pressure inside the rock and soil. This leads to a continuous strengthening of the seepage effect, reaching a stable state. The results of this study are crucial. It not only reveals the mechanism of interaction between water and rock but also correlates the degree of internal damage in rock and soil based on the seepage characteristics between water and rock. The conclusions can provide some reference value for relevant construction methods in the analysis of the formation of water flow characteristics, the prevention of rock slope seepage disasters, and the control of water inrush in tunnel excavation. [ABSTRACT FROM AUTHOR]

The mining of coal mines in western China needs to focus on protecting groundwater. A non-hydrophilic similar material for simulating the development and hydraulic conductivity of weakly cemented overlying strata fractures was developed. Fine sand, coarse sand, and gypsum are used as aggregates. Paraffin and Vaseline are used as binders. The non-hydrophilic material ratios of weakly cemented sandy mudstone and medium-grained sandstone were determined by orthogonal experiments, and used for similar simulation tests. The results show that the non-hydrophilicity of rock-like materials can be adjusted to prevent them from softening and collapsing under the action of water. Non-hydrophilic materials of higher strength and brittleness of rocks can be achieved by adjusting the content of paraffin, fine sand, and gypsum. The non-hydrophilic materials of soft and large particle rocks can be achieved by adjusting the content of paraffin, fine sand, and gypsum. After the coal seam in a similar simulation experiment was extracted, the large area of weakly cemented rock above it underwent overall settlement and fracture. Although this part was located within the failure zone, there was no macroscopic water-conducting cracks generated. The height of the water-conducting fracture zone was lower than the height of the fracture zone classified by the traditional 'three zone' theory, which is consistent with the on-site measurements. This indicates that the prepared non-hydrophilic material is reliable. The similarity simulation method based on non-hydrophilic materials can enrich the means for studying the fracture and permeability of weakly cemented overlying rocks in coal mines. [ABSTRACT FROM AUTHOR]

The article discusses a new efficient technology for the preparation of additional water in heating networks. According to the technology, additional water is prepared through the process of cationization using polyfunctional sulfonated coal cationites regenerated with a stoichiometric amount of salt. The research was carried out according to a continuous flow scheme. To obtain accurate results, a laboratory setup was prepared by approximating the height of the cationite and the average diameter of its particles to the required values relative to the diameter of the filter (d : D < 1 : 20) by adjusting the operating regime of the filter closer to industrial conditions. The regeneration regime of the cationite is selected in such a way that the amount of salt in the filtrate during water treatment does not exceed 3–6% of the amount of salt absorbed by the cationite. The main goal of the newly developed technological regime is to reduce the specific consumption of salt during regeneration, increase the exchange capacity of the cationite, and improve both the economic and ecological indicators of the process. As a result of the research, it can be concluded that the exchange capacity of the cationite varies within the interval of 7–20% under the influence of selected factors, and when the specific consumption of salt is increased from 8 to 16 kg/m3, the exchange capacity of the cationite approximately doubles. It should be noted that when the carbonate index in the treated water increases due to the presence of carbonate and hydrogen ions, the degree of water softening increases. However, the rapid rise of the carbonation value in the filtrate increases the average value of the carbonate index and leads to fouling of the filter, which results in a lower exchange capacity of the cationite compared to the mentioned values. It should be emphasized that depending on the values of alkalinity and specific consumption of the regenerant during the process, the filtrate volume of the treated water exiting the filter becomes 2–12% of the total volume and is characterized by saltiness. The salinity in the filtrate is neutralized by the buffer filter. [ABSTRACT FROM AUTHOR]

A low-waste combined technology for water softening, desalination, and deionization is proposed. The low-waste nature of the method is achieved through H-cationization of water using carboxylic polyacrylic ion exchange resin, followed by its deionization via reverse osmosis. If the requirements for desalinated water are high, such as when purified liquid is used for feeding supercritical pressure once-through boilers (SPB), it is additionally treated using ion exchange. The preconcentrate from reverse osmosis is processed through electrodialysis or electrolysis to yield acidic and alkaline solutions. These solutions are then used in conjunction with spent regeneration solutions from deep deionization ion exchange filters to regenerate the filter containing carboxylic polyacrylic ion exchange resin. The paper outlines the advantages of carboxylic cation exchange resins compared to sulfonated cation exchangers. A two-chamber H+,Na+-cation exchange filter operation circuit is proposed. Recirculation of the acidic portion of the spent regeneration solution from the BC storage reservoir through the H+Na+-cation exchange filter is planned to maximize the recovery of the cation exchange resin's working capacity. The specifics of regenerating carboxylic cation exchange resin with acid solution in a fluidized bed mode are presented. The acidic solution storage tank should be constructed as a reservoir with a conical bottom and a cylindrical upper part. Such tank design enables its use as a gypsum particle crystallizer and settler. This circuit of separate water H+,Na+-cationization with a decarbonizer significantly expands technological capabilities. Intermediate water decarbonization decreases the alkalinity of the Na+-cation exchange filter effluent, thereby hindering the hydrolysis of the salt form of the cation exchanger. Water obtained through magnesium ionization is advisable to be directed into the softened water stream. To prevent an increase in liquid pressure drop across the filter and a sharp decrease in filtration rate, it is proposed to pass the alkaline regeneration solution from bottom to top. [ABSTRACT FROM AUTHOR]

Extremely thick and hard roofs are difficult to break in the mining of a working face, and the large area of the suspended roof easily induces a strong ground pressure or dynamic impact disasters. The roof control of a coal mining face in a mine in western China was taken as a case study. The mineral composition, microstructure, and hydrophysical properties of the hard roof overlying the coal seam were analyzed. The characteristics of the weak-cementation strata that are prone to mud and collapse when encountering water were targeted to investigate the hydraulic softening roof-cutting and pressure relief technology. It was found that the clay mineral composition in the roof plate accounts for 60.6%. After 24 h of natural immersion, the rock strength decreased by approximately 10.3%-49%, and further immersion caused disintegration. By arranging high and low double-row water injection softening drilling holes in the cutting hole and roadway of the working face, the strength of roof rock strata in the target area was reduced, and the initial weighting step distance and weighting strength of the working face were reduced. The hydraulic softening roof-cutting pressure relief technology effectively regulated the weighting step distance of the hard roof and the peak weighting of the working face. [ABSTRACT FROM AUTHOR]

To study the catastrophic mechanisms of retrogressive landslides and assess the stability post treatment, it is essential to examine the internal factors contributing to landslides. This involves a detailed analysis of the characteristics of engineering geology, environmental conditions, and the impact of engineering construction activities on the landslide area. The comprehensive treatment schemes for landslides are determined using deep displacement monitoring and numerical analysis. It has been shown that the process of the landslide mechanism can be divided into four stages, i.e., primary structure breakage, rock mass damage deterioration, rock mass softening in water, and rainfall-induced instability failure. Rock mass damage and rainfall caused by slope excavation are the main causes and inducements of landslide instability. The monitoring results of deep displacement have shown that the sliding surface of a landslide is fully integrated. To mitigate the risk of secondary disasters, this study proposes a comprehensive set of measures based on the mechanisms of landslide instability and the support principle of a compensated traction zone. These measures include the implementation of prestressed antislide piles, the application of molten steel pipe grouting, and enhanced drainage techniques. The displacement of the slope was reduced, showing that the treatment scheme had a good reinforcement effect. [ABSTRACT FROM AUTHOR]

While drinking water treatment plants (DWTPs) are not considered a source of per‐ and polyfluoroalkyl substances (PFAS), PFAS concentrate in treatment residuals relative to their source water concentrations. Regulatory actions considered for PFAS‐impacted residuals could affect the cost and viability of conventional residual management practices. This study estimated the annual quantity of residuals generated in the United States and presents a framework for understanding how PFAS may concentrate in these residual streams. Findings of this work indicate that PFAS may substantially impact DWTP residuals management, especially coagulation and softening solids, at concentration factors greater than 100 and spent adsorbents at PFAS concentration factors greater than 10,000. If potential regulatory actions were to apply to coagulation and softening residuals, those regulations must consider impacts on disposal of more than 420,000,000 wet tons of at‐risk DWTP residuals which are generated annually. [ABSTRACT FROM AUTHOR]

In gripper tunnel boring machine (TBM) tunneling through complex geological formations, the safe and efficient recovery from large-scale collapses remains a formidable challenge. In this study, we investigate the causes of a 1246 m3 collapse that occurred during the gripper TBM tunneling in the diversion tunnel in Xinjiang, China. Various techniques including TSP seismic waves, CFC advanced water exploration, laboratory point load tests and packer permeability tests were employed for thorough research. The examination discloses that the water softening in biotite-quartz schist in fractured zones contributes significantly to the loosening and dislocation of rock layers along joints. The gripper TBM's cutterhead exacerbates this process through cutting action and vibrations, causing large-scale instability and eventual rock mass collapse. To tackle this engineering problem, we propose a three-step treatment scheme comprising "Reinforcement-Backfill-Re-excavation". Furthermore, we propose a technique to handle TBM collapses by creating a "protective shell" within the cavity. The safety and feasibility of these proposed solutions were thoroughly validated through numerical simulations. Also, we utilized the Hoek-Brown theory and Rostami prediction formula to establish recommended values for the total thrust and total torque of the TBM during the collapsed section. The proposed treatment scheme and estimated parameters were successfully applied, resulting in a comprehensive solution from collapse handling to tunneling. This study offers valuable details on effectively managing large-scale collapses in gripper TBM tunneling, which can be useful for similar tunnel engineering and improve safety and efficiency. [ABSTRACT FROM AUTHOR]

This article discusses the use of ozone as a residential water treatment tool. Ozone is a powerful oxidant that can purify and disinfect water by killing pathogens such as bacteria and viruses. It can effectively replace older methods of water treatment. Ozone is created on-site using a generator and is then injected into the water. After treatment, any remaining ozone must be removed. Ozone can also be used to treat well water by removing contaminants and improving taste and odor. It has various other applications, such as in swimming pools, aquariums, and laundry systems. Ozone water filtration provides superior oxidation without the drawbacks of chlorine or other chemical treatments. The article includes a case study that demonstrates the benefits of using an ozone system for water treatment. [Extracted from the article]

During the construction of a highway in northwest China, large deformation of mudstone caused severe deformation of and damage to side walls, initial support, and secondary lining to various extents. To reveal the causes of mudstone's large deformation in the tunnels of this highway, a comprehensive study was conducted by using engineering geological survey, on-site monitoring and measurement, indoor rock mechanics test, numerical simulation, and macroscopic analysis. For the problem of large deformation of this highway's tunnel section from YK209 + 500 m to YK210 + 030 m, the 3D finite difference method FLAC3D was used to simulate the large deformation of the wall rock and compare the deformation of the tunnel and the mechanical characteristics of the lining structure under different conditions by means of inverse analysis of the rheological characteristics of the mudstone and simulation of the softening of the mudstone in water. The research results provide a reference and basis for the construction design of similar mudstone tunnel projects. For the management of tunnel deformation, it is recommended to enhance the tunnel's drainage measures, thereby mitigating the intensification of mudstone softening when exposed to water. [ABSTRACT FROM AUTHOR]

In this work, we investigated the impact of moisture content on the dynamic mechanical properties of precast concrete members. The dynamic splitting impact test was applied to concrete specimens with different moisture contents using the split-Hopkinson pressure bar (SHPB) with a diameter of 75 mm. Further, variation laws of the waveform, stress–strain curve, damage pattern, dynamic splitting tensile strength (DSTS), strain rate, and damage evolution were analyzed. Experimental results indicate that specimen fragmentation degree increases with moisture content. The DSTS exhibited a "softening in the water" phenomenon when the moisture content was low, resulting in a decrease in strength. However, when the moisture content was high, the strength displayed a strengthening phenomenon, owing to the adhesion of internal pore water. The dynamic strength of the specimens is the macroscopic manifestation of the dynamic balance between the strain effect and moisture content. To model the effect of moisture content and strain rate, a viscoelastic damage constitutive model based on Weibull distribution was proposed and validated, considering the influence of water content and residual strength. The established model can reflect the damage stress–strain relationships of concrete with varying moisture contents under the impact load. The variation laws of associated parameters, such as Weibull distribution parameters, viscosity coefficient, and damage variables, were analyzed to explore the damage mechanism. From the experimental study, it can be concluded that moisture content is closely related to the specimens' damage pattern, and the dynamic performance of concrete, both of which can be captured by the proposed viscoelastic damage model. [ABSTRACT FROM AUTHOR]

The Wudongde reservoir region exhibits a notable prevalence of landslides within the red-bed reservoir stratum. The red bed is a clastic sedimentary rock layer dominated by red continental deposits. It is mainly composed of sandstone, mudstone, and siltstone. The lithology is diverse and uneven. In this study, we delve into the impact of mineral dissolution on the development of red-bed landslides in the reservoir area by utilizing the Xiaochatou landslide as a representative case study. Considering the inherent susceptibility of red-bed formations to erosion, collapse, and softening when exposed to water, an investigation was conducted to examine the consequences of mineral dissolution on landslides occurring in these areas. We conducted a mineral analysis and an identification of rock samples from the Xiaochatou landslide site, revealing alternating layers of sandstone and mudstone. Sandstone and conglomerate specimens were immersed in deionized water, and advanced techniques such as scanning electron microscopy (SEM), ion chromatography (IC), and inductively coupled plasma (ICP) analysis were used to examine the effects of water immersion. We also employed the hydrogeochemical simulation software PHREEQC to understand the dissolution mechanism of gypsum during soaking. Our findings reveal that sandstone and conglomerates harbor a notable quantity of gypsum, which readily dissolves in water. Prolonged immersion leads to erosion cavities within the sandstone, thereby augmenting its permeability. The concentration of SO42− ions in the soaking solution emerges as the highest, followed by Ca2+ and Na+. The notable significance is the dissolution of gypsum, whose intricate mechanism is contingent upon diverse environmental conditions. Variations in ion concentration profoundly influence the saturation index (SI) value, with the pH value playing a crucial role in shifting the reaction equilibrium. Regarding the deformation mode of the landslide, it manifests as a combination of sliding compression and tension cracking. The fracture surface of the landslide assumes a step-like configuration. As the deformation progresses, the mudstone layer takes control over the sliding process, causing the sandstone to develop internal narrow-top and wide-bottom cracks, which propagate upward until the stability of the slope rock mass is compromised, resulting in its rupture. In this manuscript, we delve into the dissolution traits of red-bed soft rock in the Wudongde reservoir area, using a landslide case as a reference. We simulate this rock's dissolution under environmental water influences, examining its interaction with diverse water types through rigorous experiments and simulations. This study's importance lies in its potential to shed light on the crucial engineering characteristics of red-bed soft rock. [ABSTRACT FROM AUTHOR]

This study investigates the shear characteristics of soil-rock mixtures, a critical factor influencing slope stability in engineering construction. Soil-rock mixtures, often exhibit poor integrity and can easily soften in water due to geological influences. The YT1200 direct shear drawing friction system was employed to conduct shear tests, analyzing the effect of varying water content and fine particle mass fraction under different normal stresses. Utilizing fractional derivatives, we formulated a fractional derivative shear model. Test results illustrated a softening phenomenon post achieving peak shear stress in the soil-rock mixture. It was found that peak shear stress is directly proportional to the normal stress, and inversely proportional to both water content and fine particle mass fraction. Additionally, the cohesion and internal friction angle decrease according to a power function with increasing water content, and non-linearly decrease with the rise of fine particle mass fraction. The proposed shear model aptly simulates the entire shear failure process of the soil-rock mixture, effectively analyzing the influence of key factors on shear characteristics. These findings contribute to the strength prediction and numerical simulation of soil-rock mixtures, thereby aiding in the design of reinforcement schemes and slope stability analysis. [ABSTRACT FROM AUTHOR]

This article emphasizes the importance of using science and engineering to solve water-quality issues. It highlights the need for testable and measurable hypotheses in order to ensure reliable and effective solutions. The article also discusses the significance of adhering to scientific laws and theories, and the importance of looking for real science when considering new technologies or solutions. It emphasizes the need for certifications and standards, such as those provided by NSF, to ensure the effectiveness and reliability of water treatment systems. [Extracted from the article]

Reverse osmosis (RO) membranes are widely used in seawater and brackish water desalination. Although RO membranes achieve high salt removal > 99%, their application is hindered by fouling, thus causing reduction in permeate flux, salt rejection and degradation of the membrane leading to shorter membrane lifespan. This study reviewed fouling of RO membrane during desalination processes. Also, nanofiltration (NF) membrane are briefly discussed due to their remarkable salt rejection efficiency for water softening. Various types of fouling, mechanisms and governing parameters are discussed in detail. The implications of fouling on membrane physicochemical properties and filtration performance are reviewed. Fouling mitigation strategies are presented, predominantly focusing on currently adopted methods. New fouling mitigation strategies are presented together with their challenges and feasibility assessment for adoption at pilot scale. Finally, recommendations are made on possible pretreatment approaches with the potential fouling reduction in seawater desalination. • Fouling alters membrane physico-chemical properties leading to poor performance. • The operation cost of NF and RO increases upon membrane fouling. • Chemical cleaning degrades polymeric membranes and reduces their lifespan. • New environmentally friendly fouling control methods have potential for the future. • Membrane surface modification improves antifouling properties. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this article is to determine the parameters of the preparation process for devulcanized and pyrolytic crumb rubber modified asphalt (DCRMA) and then study the rheological and microscopic properties of DCRMA through experiments. Design/methodology/approach: In this study, a new preparation process for DCRMA was developed, then the penetration, softening point and viscosity tests were employed to determine the parameters of the preparation process. The crumb rubber (CR) solubility, Fluorescence microscopy (FM), Fourier Transform Infrared (FTIR) spectroscopy and thermogravimetric analysis tests were conducted to verify the devulcanized and pyrolytic effectiveness of the preparation process. Furthermore, dynamic shear rheometer and bending beam rheometer were used to characterize the high and low-temperature rheological properties of DCRMA. Findings: The results showed that the penetration balanced the CR degradation and the virgin asphalt aging well and thus could be used as a main parameters control indicator. The CR solubility, FM and FTIR tests proved that the CR has been fully devulcanized and pyrolytic via the preparation process. The DCRMA exhibited better low-temperature and fatigue performance and lower rutting performance than the conventional crumb rubber modified asphalt (CRMA) with the same CR content. Finally, the time–temperature superposition principle could be employed for all binders in this study. Originality/value: A new preparation process for DCRMA was developed. [ABSTRACT FROM AUTHOR]

To gain insight into the reduction mechanism of water on the dynamic destabilization failure character of coal under mining disturbance conditions, the effect of water on the damage and energy dissipation feature of coal was investigated via cyclic uniaxial compressive loading–unloading test, acoustic emission (AE) monitoring technology, and theoretical analysis. It manifests that the softening effect of water on the mechanical properties of coal is still remarkable, lower uniaxial compressive strength and elastic modulus, while greater axial strain and higher Poisson's ratio are observed under the cyclic loading–unloading condition. Water‐saturated specimens dissipate more energy during the cyclic loading–unloading process, which reduces the proportion of input energy accumulated in the coal mass, thus lowering the burst proneness of coal. A greater amount of damage generates in air‐dried specimens than that in water‐saturated specimens at the first cyclic loading–unloading cycle, while lower damage increments are observed in the following cycles. This may be the reason for the minimal energy dissipation of air‐dried specimens in the following cycles. The elastic modulus behaves logarithmically versus the increasing cyclic loading–unloading cycle counts. The energy dissipated due to the damage evolution and plastic deformation of coal specimens positively correlates with the energy released by AE activities, the AE energy in air‐dried specimens has a greater concentration around the peak axial stress and a stronger correlation with the dissipated energy. The cumulative AE energy and energy dissipation density are linearly correlated during the cyclic loading–unloading process, which indicates a possibility in estimating the damage evolution and the dynamic failure risk of coal via cumulative AE energy, under the cyclic loading–unloading condition. [ABSTRACT FROM AUTHOR]

In this paper, phosphogypsum-based polymer foam lightweight soil was prepared by taking phosphogypsum as fine aggregate and adding coagulant and prefabricated foam. The changes in the properties of the material were studied deeply in terms of flow rate, setting time, mechanical properties, water absorption and softening coefficient, combined with XRD and SEM for microscopic testing. The results show that mortar test blocks with excellent performance can be prepared under the conditions of sand-to-ash ratio 0.6, water-to-material ratio 0.5 and quicklime 4%. The initial and final setting times are 210 and 260 minutes, the compressive strength of the specimen can reach 2.8 MPa after 3 days, and 11.9 MPa after 28 days. Foam lightweight soil with different wet density can be prepared by adjusting the amount of prefabricated foam, providing a new way for phosphogypsum resource application. [ABSTRACT FROM AUTHOR]