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In this paper we investigate the statics and the dynamics of large-viscosity ligaments attached to a rod and drawn out of a pure-liquid bath. Following the similar work of films pulling out of a bath (Champougny et al., J. Fluid Mech., vol. 811, 2017, pp. 499–524), a one-dimensional model is applied to describe the ligaments drawn at constant velocities. We focus on the whole drawing dynamics of the ligament up to breakup, for which the breakup height is determined. The breakup height coincides with the maximum static meniscus height for very slow drawing, whose process can be described by quasi-static solutions. We present the numerical results of the static menisci and analytically unravel the mechanism in the low gravity case. Starting from a stable static meniscus, the breakup height of faster drawing depends separately on the rod radius and the drawing velocity, the latter dependency being fully determined by considering the agravic limit. Next, it is shown that the entire lifetime of the ligament drawing can be sequenced into a ductility stage, a capillarity stage and a pinch-off stage, the latter being shown to be almost instantaneous. The ductility and capillarity stages are decorrelated with the help of an approximate solution of the ductility stage, and the transition between the two stages corresponds to the time at which the capillarity-induced contraction velocity exceeds the ductility-induced one. The one-dimensional predictions of the breakup height and the entrained liquid volume attached to the rod quantitatively agree with experimental results of silicone oil ligaments, and the deviations are rationalized in comparison with a two-dimensional model. [ABSTRACT FROM AUTHOR]

Soil physical quality is largely determined by interphase interactions at variable moisture content. This phenomenon allows us to consider the water retention curves as functions of the water content and its thermodynamic potentials as indicators of the soil physical quality and its dynamics. Diagrams of the physical quality of soils represented by water retention curves with areas of dominance of certain physical mechanisms and forces responsible for the interaction of physical phases were obtained for Eurasian soils included in the database (more than 400 samples) and grouped by five FAO/USDA textural classes. Original instrumental methods using centrifugal, gravitational, and temperature physical fields for water removal made it possible for the first time to obtain the thermodynamic characteristics of water retention in the entire range of soil water potential from 0 to 1 million J/kg. The main fundamental result is a physically based methodology for diagnosing the limiting (critical) values of the soil water content and its thermodynamic potentials, which divide the areas of dominance of various forms of soil moisture, physical forces, and mechanisms of interphase interactions on the diagrams of the physical quality of soils. The significance of non-capillary surface forces and mechanisms controlling water retention and physical quality of soils is shown. The results of determination of the optimal ranges of water content for Eurasian soils of different textures and geneses in connection with their soil-ecological and technological functions and services specify practical significance of this study. [ABSTRACT FROM AUTHOR]

The use of chemical admixtures seeks to improve the properties of concrete and its efficiency is directly linked to the chemical interaction with cement. Thus, this study evaluates the influence of the use of plasticizer admixtures from four different suppliers in the production of concrete. One concrete mix was analyzed, considering four types of plasticizer admixtures and two types of Portland cement. In the fresh state of the concrete, the workability was analyzed through the consistency determined by the slump test, in a time defined as initial and after 30 minutes, to evaluate the ability to maintain this workability. In the hardened state, the compressive strength analysis was performed at 7, 28 and 63 days of age, and the capillary water absorption test at 28 days. The study showed that the brand of the plasticizer admixture, as well as the type of cement, influences the workability of the mixtures. Still, in the hardened state, when the statistical analysis of the results was performed, it was identified that the two variables have a significant influence on the compressive strength and on the water absorption by capillarity of the concretes. [ABSTRACT FROM AUTHOR]

Liquid properties are relevant for the understanding of fundamental and applied sciences. Among these properties, those that can be traced back and explained through the surface tension are particularly interesting to study and reconstruct in educational terms. Traditional educational treatment of surface tension is often obscure or too complex, sometimes superficial or completely neglected. The aim of the research here described is to discuss in detail a mesoscopic model of liquids and show quantitative results obtained by a computer simulation approach. Looking at the educational aspect, the main advantage of this approach is that it allows the student/teacher to control the simulation parameters and understand step by step how the physical quantities influence the investigated system. Some of the main properties of capillarity phenomena (meniscus formation, capillary rise, etc) are analysed through the simulation of a liquid in a tray with a capillary tube inside, where a value of surface tension is obtained. [ABSTRACT FROM AUTHOR]

Two coupled time-dependent two dimensional nonlinear Schrödinger equations have been derived using multiscale expansion for two nonlinearly interacting capillary-gravity waves over an infinite depth of water. These equations are then utilised to discuss the modulational (Benjamin-Feir) instability of two Stokes wavetrains due to unidirectional and bidirectional perturbations. It is found from the graphs and the three-dimensional contour plots that the rate of growth of instability for two wave packets interacting obliquely is higher than the instance of modulation of one wave packet. We have likewise examined the influence of capillarity on modulational instability. [ABSTRACT FROM AUTHOR]

The typical characteristic of a thin porous layer is that its thickness is much smaller than its in-plane dimensions. This often leads to physical behaviors that are different from three-dimensional porous media. The classical Richards equation is insufficient to simulate many flow conditions in thin porous media. Here, we have provided an alternative approach by accounting for the dynamic capillarity effect. In this study, we have presented a set of one-dimensional in-plane imbibition and subsequent drainage experiments in a thin fibrous layer. The X-ray transmission method was used to measure saturation distributions along the fibrous sample. We simulated the experimental results using Richards equation either with classical capillary equation or with a so-called dynamic capillarity term. We have found that the standard Richards equation was not able to simulate the experimental results, and the dynamic capillarity effect should be taken into account in order to model the spontaneous imbibition. The experimental data presented here may also be used by other researchers to validate their models. Article Highlights: We have presented a set of one-dimensional in-plane imbibition and subsequent drainage experiments in a thin fibrous layer. The experimental data were simulated using the Richards equation either with classical capillary equation or with a so-call dynamic capillarity term. The dynamic capillarity effect should be taken into account in order to model the spontaneous imbibition. [ABSTRACT FROM AUTHOR]

In this article, we analyze how candidates for the legislative branch of Campo Mourão used religious elements in their posts on Facebook and Instagram during the 2020 election period. Between August and November, we collected materials published in the fan pages and personal profiles of 26 candidates, such as flyers, photos, videos and jingles. We identified the employment of sacred signs in three axes of analysis that systematize the use of this religious capital in the campaign: intensity, form and style. The Churches' political project to occupy the public space by means of participation in the elections remains the main way to put their "visibility strategies" into practice, disseminating references and seeking greater legitimacy and social capillarity. The case addressed is inserted in a larger repertoire, regarding the connections between religion and politics that, especially since the 2018 national elections, is marked by new dynamics and logics of power. [ABSTRACT FROM AUTHOR]

Key points: Capillary rarefaction is hypothesized to contribute to impaired exercise tolerance in cardiovascular disease, but it remains a poorly exploited therapeutic target for improving skeletal muscle performance.Using an abdominal aortic coarctation rat model of compensatory cardiac hypertrophy, we determine the efficacy of aerobic exercise for the prevention of, and mechanical overload for, restoration of hindlimb muscle fatigue resistance and microvascular impairment in the early stages of heart disease.Impaired muscle fatigue resistance was found after development of cardiac hypertrophy, but this impairment was prevented by low‐intensity aerobic exercise and recovered after mechanical stretch due to muscle overload.Changes in muscle fatigue resistance were closely related to functional (i.e. perfused) microvascular density, independent of arterial blood flow, emphasizing the critical importance of optimal capillary diffusion for skeletal muscle function.Pro‐angiogenic therapies are an important tool for improving skeletal muscle function in the incipient stages of heart disease. Microvascular rarefaction may contribute to declining skeletal muscle performance in cardiac and vascular diseases. It remains uncertain to what extent microvascular rarefaction occurs in the earliest stages of these conditions, if impaired blood flow is an aggravating factor and whether angiogenesis restores muscle performance. To investigate this, the effects of aerobic exercise (voluntary wheel running) and functional muscle overload on the performance, femoral blood flow (FBF) and microvascular perfusion of the extensor digitorum longus (EDL) were determined in a chronic rat model of compensatory cardiac hypertrophy (CCH, induced by surgically imposed abdominal aortic coarctation). CCH was associated with hypertension (P = 0.001 vs. Control) and increased relative heart mass (P < 0.001). Immediately upon placing the aortic band (i.e. before development of CCH), post‐fatigue test FBF was reduced (P < 0.003), coinciding with attenuated fatigue resistance (P = 0.039) indicating an acute arterial perfusion constraint on muscle performance. While FBF was normalized during CCH in chronic groups (P > 0.05) fatigue resistance remained reduced (P = 0.039) and was associated with reduced (P = 0.009) functional capillarity after development of CCH without intervention, indicating a microvascular limitation to muscle performance. Normalization of functional capillarity after aerobic exercise (P = 0.065) and overload (P = 0.329) in CCH coincided with restoration to control levels of muscle fatigue resistance (P > 0.999), although overload‐induced EDL hypertrophy (P = 0.027) and wheel‐running velocity and duration (both P < 0.05) were attenuated after aortic banding. These data show that reductions in skeletal muscle performance during CCH can be countered by improving functional capillarity, providing a therapeutic target to improve skeletal muscle function in chronic diseases. Key points: Capillary rarefaction is hypothesized to contribute to impaired exercise tolerance in cardiovascular disease, but it remains a poorly exploited therapeutic target for improving skeletal muscle performance.Using an abdominal aortic coarctation rat model of compensatory cardiac hypertrophy, we determine the efficacy of aerobic exercise for the prevention of, and mechanical overload for, restoration of hindlimb muscle fatigue resistance and microvascular impairment in the early stages of heart disease.Impaired muscle fatigue resistance was found after development of cardiac hypertrophy, but this impairment was prevented by low‐intensity aerobic exercise and recovered after mechanical stretch due to muscle overload.Changes in muscle fatigue resistance were closely related to functional (i.e. perfused) microvascular density, independent of arterial blood flow, emphasizing the critical importance of optimal capillary diffusion for skeletal muscle function.Pro‐angiogenic therapies are an important tool for improving skeletal muscle function in the incipient stages of heart disease. [ABSTRACT FROM AUTHOR]

In the absence of gravity, a capillary surface within a circular cylinder will have constant mean curvature and will make a constant contact angle with the cylinder. Two types of surfaces with these properties are Delaunay surfaces and cylinders (i.e., the free surface of the liquid is another circular cylinder). Stability and energy minimality of these capillary surfaces are investigated. [ABSTRACT FROM AUTHOR]

With the increase in global warming, alternative solutions to traditional concrete are being inquired today to reduce dead loads of structures and improve their thermal insulation properties. Due to these needs, foam concrete with low unit weight and superior thermal properties comes to the fore. In this study, foam concretes with different unit weight were produced with different cements. In the scope of the study, composite cements consisting of CEM II, CEM II and CEM IV were used. 9 different mixtures were obtained with foam contents of 30, 60 and 90 kg/m3. 0-1 mm waste tires were used as aggregate in the production of foam concretes. As the foam content increased, the apparent porosity and water absorption values of concrete increased, while the unit weight values decreased. The unit weights of foam concretes range from 595-980 kg/m3. 28-day compressive strength ranges from 0.53-1.56 MPa. As the foam content of foam concretes increased, the depth of water penetration decreased. Water penetration depths of foam concrete are between 2.6-8.2 mm. As a result of two-way ANOVA analysis, the change in cement type does not affect the properties of foam concrete. But the change in foam content can directly affect the properties of foam concrete. The mechanical properties of foam concrete produced from CEM III type cement are higher than other cement types. As a result, it was determined that waste tires that are harmful to the environment and human health can be used in the production of foam concrete. It is estimated that foam concrete produced with waste rubber aggregate will show a closer thermal property than brick. [ABSTRACT FROM AUTHOR]

[Display omitted] Contact angle measurements alongside Young's equation have been frequently used to quantitatively characterize the wettabilities of solid surfaces. In the literature, the Wenzel and Cassie-Baxter models have been proposed to account for surface roughness and chemical heterogeneity, while precursor film models have been developed to account for stress singularity. However, the majority of these models were derived based on theoretical analysis or indirect experimental measurements. We hypothesize that sub-nanometer-scale in situ investigations will elucidate additional complexities that impact wettability characterization. To develop further insights into in situ wettability, we provide the first direct experimental observation of fluid-solid occupancies at three-phase contacts at sub-nanometer resolution, using environmental transmission electron microscopy. Considering the partially spreading phenomenon and capillarity, we provide an improved physics-based interpretation of measuring the sub-nanometer-scale contact angle at the inflection point of the fluid-fluid interface. The difference between this angle and the commonly-used apparent one measured at a lower resolution is also discussed. Furthermore, we provide direct experimental evidence for the density differences between the adsorbed wetting film and the bulk wetting phase. For the effect of surface roughness, the applicability of the Wenzel model is discussed based on the observed in situ solid-fluid occupancies. [ABSTRACT FROM AUTHOR]

Two-phase incompressible flow in porous media plays an important role in various fields including subsurface flow and oil reservoir engineering. Due to the interaction between two phases flowing through the pores, the fluid–fluid friction force may have a significant effect on each phase velocity. In this paper, we propose an energy stable (thermodynamically consistent) Maxwell–Stefan–Darcy model for two-phase flow in porous media, which accounts for the fluid–fluid friction. Different from the classical models of two-phase flow in porous media, the proposed model uses the free energy to characterize the capillarity effect. This allows us to employ the Maxwell–Stefan model to describe the relationships between the driving forces and the friction forces. The driving forces include the pressure gradient and chemical potential gradients, while both fluid–solid and fluid–fluid friction forces are taken into consideration. Thermodynamical consistency is the other interesting merit of the proposed model; that is, it satisfies an energy dissipation law and also obeys the famous Onsager's reciprocal principle. A linear semi-implicit numerical method is also developed to simulate the model. Numerical simulation results are provided to show that the fluid–fluid friction force can improve the oil recovery substantially during the oil displacement process. [ABSTRACT FROM AUTHOR]

The methods and results of the mathematical simulation of nonlinear waves generated by hydrodynamic instability in traveling capillary films of a viscous liquid are discussed. Two model systems of differential equations for the local values of the layer thickness h and the fluid flow rate q are considered. The single-parameter (h–q) Kapitsa–Shkadov model that ensures the effective simulation of low-viscosity liquid film flows has received wide acceptance in world literature devoted to film hydrodynamics. The two-parameter (h–q)1 model extends the possibilities for direct calculation of nonlinear waves in the higher viscosity liquid films. A succession of the systems of model equations is given, the scenarios of instability and bifurcation are discussed, and the results of calculations of wave structures in comparison with the experimental data are given. [ABSTRACT FROM AUTHOR]

The rail system in the Recife region can transport approximately 400,000 passengers daily. Failure drastically decreases its carrying capacity. An example of a failure that occurs frequently is the so-called false occupancy failure. False occupancy failures occur when the train detection mechanism for part of the route is defective, forcing the driver to take manual control, increasing the risk of accidents. One of the solutions is to increase the capillarity of the railway system by adding alternative routes. In this context, this work proposes a set of models for evaluating the performability of railway systems. A case study using the Recife railway system was used to show the applicability of the proposed models, where it was possible to increase the system availability by practically 50% with the addition of alternative routes, also improving the performance metrics. [ABSTRACT FROM AUTHOR]

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The flow of a film of a viscous liquid is considered. The liquid is a weak solution containing a gas phase and a volatile surfactant. The distribution of the latter in the layer is controlled by the diffusion in the liquid volume, the adsorption–desorption processes between the liquid volume and the adsorbed near-surface layer, and the evaporation from the surface into the boundary gaseous medium. The process of the gas phase penetration from the external gas flow is specified by the diffusion inside the film. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the vanishing capillarity–viscosity limit of the incompressible Navier–Stokes–Korteweg (NSK) equations in a three-dimensional horizontally periodic strip domain, in which the velocity of the fluid is supplemented with slip boundary condition and the gradient of density with Dirichlet boundary condition on the boundary. We prove that there exists an positive constant T 0 independent on the capillarity and viscosity coefficients, such that the incompressible NSK equations have a unique strong solution on [ 0 , T 0 ] and the solution is uniformly bounded in H 3. Based on the uniform estimates, we further give the convergence rate in H 1 from the solutions of the incompressible NSK equations to the solution of the inhomogeneous incompressible Euler equations as the capillarity and viscosity coefficients go to zero simultaneously. [ABSTRACT FROM AUTHOR]

• Capillary and diffusion forces facilitate the transfer of water from brine to ScCO 2 within cement. • Cement corrosion in a wet ScCO 2 environment is pronounced. • The most extensively corroded area in wellbore cement is located at the interface between ScCO 2 and water. • The expansion rate of the corroded region plays a pivotal role in assessing the potential for CO 2 leakage. In geological CO 2 storage conditions, wellbore cement can be exposed to both supercritical CO 2 (ScCO 2) with water vapor, and CO 2 dissolved in water. There is a lack of studies that investigate the effects of reaction environments on the extent of CO 2 -induced cement carbonation and leaching. In this study, four CO 2 exposure experiments were designed with wellbore cement samples exposed to both ScCO 2 and CO 2 dissolved in water to investigate the impacts of evaporation, capillarity, diffusion, and salt deposition on cement carbonation. Severe cement carbonation after 14 and 28 days of CO 2 exposure was observed in a wet ScCO 2 phase. When water evaporation into ScCO 2 phase was minimized by a steel plate between the brine phase and the ScCO 2 phase, a strong cement carbonation in ScCO 2 phase was still visible. The reason was that imbibition and diffusion drove water to migrate from the lower section to the upper section of the cement sample to participate in the carbonation reaction. The level of cement carbonation in different CO 2 exposure environments was ranked as: wet ScCO 2 > CO 2 dissolved in water > Pure-ScCO 2. The corresponding maximum carbonation area ratios were 90 % and 38 % for the wet ScCO 2 scenario and the brine scenario, respectively, compared with a maximum carbonation area ratio of 20 % for the Pure-ScCO 2 scenario. This study implies that the most altered region in wellbore cement is at the ScCO 2 —water interface, and the expansion rate of the altered region is the key to evaluate the potential for CO 2 leakage through wellbore cement. [ABSTRACT FROM AUTHOR]

[Display omitted] Carbon dioxide-enhanced oil recovery (CO 2 -EOR) is an important means of improving oil recovery while lowering greenhouse gas emissions. However, it is still challenging to determine the pore-scale flow characteristics and interfacial interaction parameters, such as the wettability, interfacial curvature, and capillary pressure, under near-miscible conditions. In this study, X-ray microtomography (micro-CT) was used to determine the morphology of gas and oil phases and characterize the in-situ wettability under near-miscible conditions. The mean contact angle increased from 66.99° to 72.5° as the injected CO 2 pore volume (PV) increased from 5.5 PV to 33.1 PV. The wettability was locally altered as the local contact angle changed from 44.14° to 107.27° because of preferential adsorption of CO 2 molecules over oil molecules on solid surfaces. The mixed-wet condition was reflected by local contact angles both below and above 90°, and the capillary pressure exhibited a tower-shaped distribution with a peak value around zero, which promoted oil recovery. At the end of the displacement process, the interfaces were pushed toward the corners by a reduction in the capillary pressure, resulting in interface recession and a reduction in CO 2 clusters. Pore occupancy studies showed that under near-miscible conditions, gas usually occupies large pores and oil resides in pores of varying sizes, which can result in optimal recovery. [ABSTRACT FROM AUTHOR]

The research article aims to investigate the hygroscopic behavior of water absorbed by capillarity in clay supplemented with Alfa fibers. This specific clay-fiber composite holds significant importance in Moroccan construction practices. The primary aim is to enhance comprehension and control over the material's hydrothermal behavior by investigating moisture absorption traits, responses to varying humidity and temperature conditions, and the influence of fiber reinforcement on moisture equilibrium and structural stability. As temperature levels rise, the equilibrium water content absorbed through capillarity demonstrates a downward trend. The introduction of Kaolin-Alfa fibers into the clay composite profoundly affects the pace at which equilibrium moisture content is lost. This attribute effectively mitigates the likelihood of cracks developing in earthen structures during the drying phase, as it uniformly disperses tensions resulting from shrinkage. The findings showed that by understanding its unique region, Predictions regarding the sorption tendencies of other building materials are possible because of the approximate estimation of Clay-Kaolin reinforced with Alfa fibers sorption behavior. Surface flaws arise on Clay-Kaolin reinforced with Alfa fibers as a result of rising average pore radius and spreading pressure brought on by rising temperature and relative humidity. Furthermore, the heightened average pore volume observed in regions characterized by elevated relative humidity levels precipitates various defects within building materials, a phenomenon that has a discernible impact on their durability. [ABSTRACT FROM AUTHOR]

Droplet evaporation, a fundamental process with wide-ranging applications, involves complex physical mechanisms that significantly influence mass transfer rates and droplet lifetimes. Despite its significance, the influence of droplet deformation induced by capillary forces on local saturation conditions and its subsequent impact on phase change have received limited attention. This study delves into the impact of capillary-induced droplet deformation on local saturation conditions and its subsequent effect on phase change within a quiescent vapor environment. Contrary to most analytical and numerical studies that impose temperature and heat flux conditions at the vapor–liquid interface, our investigation employs direct numerical simulations based on the thermal Navier–Stokes–Korteweg model, capturing the dynamics of the droplet and its interface without relying on ad-hoc interface conditions. Our findings demonstrate that droplet deformation induces free oscillatory motion, which, although not significantly altering droplet lifetime due to viscous damping, leads to non-uniform mass fluxes along the droplet interface. We observe that areas of higher curvature are associated with increased local pressure and reduced temperatures, a discrepancy primarily attributed to evaporative cooling. This effect is further elucidated through an analysis of pressure and energy fluxes, revealing that regions of high curvature experience significant heat consumption, driving evaporative cooling and creating temperature gradients along the interface. Conversely, areas with negative curvature exhibit a reverse trend, indicating the complex interplay of capillarity, deformation, and phase change in droplet evaporation. Our results highlight the intricate relationship between droplet deformation, local pressure, mass flux, and temperature, underscoring the necessity for improved modeling of these factors in future studies on droplet evaporation dynamics. [Display omitted] • Droplet evaporation via Navier–Stokes–Korteweg and van der Waals equation of state. • Impact of droplet deformation on mass flux and temperature during evaporation. • Droplet deformation leads to non-uniform mass and energy fluxes along the interface. • Curvature impacts local saturation and evaporation characteristics. • High curvature boosts evaporation and cools temperatures. [ABSTRACT FROM AUTHOR]

The lubricating layer of Slippery Liquid-Infused Porous Surfaces (SLIPS) has certain fluidity and low friction coefficient so that it can serve as a good barrier and protection effect. However, common SLIPS suffer from poor oil-holding capacity that lubricating oil is easy to be washed away and irreparable in practical application. Inspired from self-lubricating earthworm skin, we demonstrate a nanochannels surface covered by silicone-oil-infused polydimethylsiloxane (PDMS), which could form continuous self-complement lubricating layer. The strong capillarity of the confined nanochannels showed self-repairing properties of injected liquid film, which can recover lubricating performance quickly after physical damage for many times, exhibiting high stability. This study provides a simple and reliable way for the preparation of long-term effective antifouling functional interface materials. [ABSTRACT FROM AUTHOR]

We present an approach to the problem of the blow up at the triple junction of three fluids in equilibrium. Although many of our results can already be found in the literature, our approach is almost self-contained and uses the theory of sets of finite perimeter without making use of more advanced topics within geometric measure theory. Specifically, using only the calculus of variations we prove two monotonicity formulas at the triple junction for the three-fluid configuration, and show that blow up limits exist and are always cones. We discuss some of the geometric consequences of our results.

This paper studies modifications made to the Bosanquet equation in order to fit the experimental observations of the liquid filling process in circular tubes that occurs by capillary force. It is reported that there is a significant difference between experimental observations and the results predicted by the Bosanquet equation; hence, it is reasonable to investigate these differences intensively. Here, we modified the Bosanquet equation such that it could consider more factors that contribute to the filling process. First, we introduced the air flowing out of the tube as the liquid inflow. Next, we considered the increase in hydraulic resistance due to the surface roughness of the inner tube. Finally, we further considered the advancing contact angle, which varies during the filling process. When these three factors were included, the modified Bosanquet equation was well correlated with the experimental results, and the R square—which indicates the fitting quality between the simulation and the experiment—significantly increased to above 0.99.

This paper aims to enhance the performance of Newton–Krylov solvers for coupled poromechanical problems with two‐phase flow. In particular, we investigate the impact of capillary pressure on preconditioning strategies. Capillarity complicates the coupling between the solid deformation and fluid pressure degrees of freedom, as well as increases the nonlinearity of the system. Depending on the capillary pressure relation used in the constitutive formulation, the flow equations may exhibit a spectrum of advection‐dominated to diffusion‐dominated behavior. We propose preconditioning approaches that account for this behavior and lead to robust numerical performance within a broad range of regimes. [ABSTRACT FROM AUTHOR]

In this study, the densification during the formation of WC-based coating prepared by electric contact strengthening (ECS) was investigated. Under increasing ECS process unit time, the surface and cross-sectional morphology, element distribution, hardness and phase composition of WC-based coating were detected. And the wear tests were conducted to test the coating performance. The results showed that, with the prolongation of ECS time, the coatings became denser while the porosity ratio decreased from 10.14% to 1.05%; The hardness of the coatings increased and the worn loss decreased continuously. It was found that, by the heating-pressing action of ECS, the WC-based powder geometry could maintain the original sphere shape, while the pores were filled gradually. The A4 coating showed the lowest wear rate. The densification mechanism was deduced that the intensified capillarity at the interface between the hard phase and binder phase due to the heating-pressing action, which showed forced infiltration and creeping behavior of the binding phase. [ABSTRACT FROM AUTHOR]

The addition of polymer emulsion in cement paste improves concrete impermeability. However, a high polymer emulsion content (usually 10%–20% of the mass of cement) is typically required to significantly improve the performance of concrete, which might increase material costs and decrease the compressive strength of concrete. This study seeks to develop a better method for improving concrete impermeability without significantly decreasing the concrete strength at a relatively low polymer emulsion content. In this study, the aggregates were pretreated with asphalt emulsion to concentrate hydrophobic asphalt film in the interfacial transition zone (ITZ). The effects of asphalt emulsion-coated aggregate (ACA) on the transport and mechanical properties of concrete were investigated. The aggregates were pretreated with asphalt emulsion at dosages of 0.1%, 0.4%, 0.7%, and 1.0% mass of the coarse aggregates, and the replacement percentages of normal coarse aggregates (NCA) by ACA were 10%, 30%, 50%, 70%, and 90%. Water absorption (WA) by capillarity, compressive strength, and stress-strain curves were obtained. The porosity and microhardness of ITZ around ACA were also investigated. The results indicated that the porosity of ITZ within 20 μm of the aggregate surfaces increased over two times, and its microhardness decreased by approximately 30% when the coated asphalt emulsion content increased to 0.7% and 1.0%, thus decreasing the concrete strength by approximately 20%. The WA rate was influenced by the mutual effects of the hydrophobicity of asphalt film and increased porosity in ITZ. The proper replacement percentage of NCA by ACA (30%) improve concrete impermeability and reduce concrete brittleness without significantly decreasing the concrete strength at a relatively low asphalt emulsion content (0.4% mass of coarse aggregates). [ABSTRACT FROM AUTHOR]

In this paper, we investigate experimentally and numerically the dynamics of the drainage of a transparent capillary tube (radius 0.4 mm). A non-wetting fluid (gas) displaces a wetting fluid (oil). The gas phase is continuously injected at an extremity of the capillary tube (inlet section) at a constant injection-rate Q inj , ranging from 0.1 to 10 ml/h, corresponding to capillary numbers Ca varying between 5 · 10 - 4 and 5 · 10 - 2 . Oil phase, initially filling the tube, leaves the system at the second opened extremity (outlet section).We consider in this work the compressibility of non-wetting fluid (gas), viscous forces in the liquid column, capillary forces and gravity. The effect of several parameters, such as Q inj j and gravity, on the progress of the gas–liquid interface has been investigated. [ABSTRACT FROM AUTHOR]

In recent years, the need for portable, low-cost, and eco-friendly devices for testing and monitoring has arisen. Paper-based devices have emerged as a response to these needs due to the properties induced by capillarity, flexibility, disposability, and biodegradability. In this work, the authors explored the possibility of tuning the hygro-mechanical response of paper-based cantilever beams using glycerol. A lumped-parameter model with non-linear stiffness is used to describe the dynamic response of the beams using three parameters. An experimental method based on resonance frequency tests is used to study the influence of glycerol on the dynamic response of four different beam configurations. The obtained results demonstrate that the resonance frequency of paper-based mechanical systems can be easily tuned by the imbibition of a glycerol–water solution. This study could lead to the development of tunable paper-based mechanical systems for specific applications such as energy harvesters and hygro-mechanical-based sensors. [ABSTRACT FROM AUTHOR]

Realizing ultrathin water and generating an abundant water/air interface in the interconnected pores of photothermal materials is an effective way to boost the solar‐driven water evaporation rate, but still a great challenge. Herein, confinement capillarity (CC) of photothermal thin coating on porous sponge for significantly enhancing the solar‐driven water evaporation is proposed. The thin coating is composed of abundant agminated black/hydrophilic nanoparticles (BHNPs), and the channels among the BHNPs can generate strong capillarity for water transportation. Water can be spontaneously limited and transported among the agminated nanoparticles, rather than fill in the interconnected pores of the sponge. Thus, ultrathin water layer can be realized on the outer/inner surface of the sponge skeleton, without precisely controlling water supply. The thin water layer can not only expose as much evaporation area as possible by increasing the vapor escape channel, but also prevent solar energy to heat excess water. Thanks to the CC, the rate of solar steam generation can be greatly improved. Moreover, the photothermal material with CC can maintain its high evaporation rate during the whole day, and can remove the salt during night time, highlighting its recyclability and anti‐salt‐accumulation property. Moreover, the CC can be readily scaled up for practical applications. [ABSTRACT FROM AUTHOR]

This paper describes attempts to replicate medieval plaster using hot-mixing, where quicklime, aggregate, and water are combined in a single exothermic process. The experimental study aimed to reproduce the structural characteristics of medieval plaster while making sample materials for conservation trials, rendering them more relevant and comparable with the medieval materials on which treatments take place. For wall painting conservation, similar capillarity and permeability are particularly important for trials focusing on consolidation, desalination, and cleaning. These characteristics are greatly influenced by the materials, working protocol, and curing conditions used in the replication process. Replicated plaster and plaster sampled from Gothic wall paintings were analysed to provide data regarding porosity, type of lime, aggregates, and binder/aggregate ratio using thin-section analyses, X-ray diffraction, porosity measurements, and mercury intrusion porosimetry. The comparative study showed a close match between one of the two recreated mortars and the original plaster. [ABSTRACT FROM AUTHOR]

This study is concerned with the large time behaviour of the three-dimensional isentropic compressible Navier–Stokes–Korteweg equations, which are used to model viscous and compressible fluids with internal capillarity. Based on the fact that the rarefaction wave is nonlinearly stable to the one-dimensional isentropic compressible Navier–Stokes–Korteweg equations, the planar rarefaction wave to the three-dimensional isentropic compressible Navier–Stokes–Korteweg equations is first constructed. Then it is shown that the planar rarefaction wave is asymptotically stable in the case that the initial data are a suitably small perturbation of the planar rarefaction wave and the strength of the rarefaction wave is small. The proof is based on the delicate energy method. The result indicate that the planar rarefaction wave of the inviscid Euler system is stable for the three-dimensional isentropic compressible fluids with physical viscosities and internal capillarity. [ABSTRACT FROM AUTHOR]

Countercurrent spontaneous imbibition (SI) is an important flow mechanism for oil recovery in fractured reservoirs during waterflooding. SI plays a key role in the mobilization of oil in the matrix because it facilitates water infiltration by capillarity even when the matrix permeability is low, which limits fluid transport by advection. However, the modeling of SI in fractured media under dynamic conditions has been insufficiently studied. Most imbibition models assume conventional exponential functions and empirical constants based on experimental results of oil recovery under static conditions. Thus, the modeling of water distribution in the fracture and the matrix has been ignored which may lead to incorrect estimates of the efficiency of countercurrent SI to recover oil. Using the classic fractional flow equation, we present a semi-analytical solution to model countercurrent SI in a water-wet fractured medium by including a transfer function to account for continuous fluid exchange between the fracture and the matrix. The model is numerically solved using finite differences by including an effective imbibition time as a function of water advance in the fracture, which overcomes the difficulty of solving iterative numerical summations as shown in other imbibition models. The novelty of the presented solution is that it enables the modeling of water infiltration in the matrix under dynamic conditions. We verified the semi-analytical model against 2D numerical simulations and validated against experimental data to demonstrate that the model accurately predicts oil recovery and water infiltration in the matrix. [ABSTRACT FROM AUTHOR]

Applying physically based models that include preferential flow (PF) is still very challenging at the catchment scale. A gravity‐driven film flow approach could be a promising concept for modeling PF as it only requires a small number of parameters. We tested if this approach can be used for different soils and land covers within a 247 km2 catchment and if we can find generalizable relationships of the film flow parameters to site or rainfall properties. We used a unique data set from a soil moisture sensor network with 135 instrumented soil profiles in three different geologies (slate, marl, and sandstone) and two land covers (forest and grassland) and fitted the film flow model to around 1,700 infiltration events. The results demonstrate that the physical relationship of film flow was capable to predict wetting front velocity (v) and flow parameters from rainfall input (qs) alone. This relationship was pronounced in grassland sites but weaker for forest sites, probably due to heterogeneity of the rainfall input underneath the canopy. Incorporating the water content into the v‐qs relationship did not improve the quality, but showed that for the film flow the rainfall input and hence gravity is in fact the dominant driver and not capillarity. Furthermore, abstraction of water into the soil matrix during film flow is an important process to be included into the framework with reasonable agreements for marl and sandstone using a multiple linear regression. Film flow and corresponding functional parameter relationships for other regions could improve catchment wide PF modeling in the future. Key Points: Gravity‐driven film flow has a large potential to describe preferential flow during natural infiltration events at a diversity of sitesParameters can be determined from the rainfall input, which has a stronger effect on the flow velocity than initial soil water contentAbstraction of water from film flow in macropores into the soil matrix is a process that has to be included in more detail [ABSTRACT FROM AUTHOR]

Capillary-driven action is an important phenomenon which aids the development of high-performance heat transfer devices, such as microscale heat pipes. This study examines the capillary rise dynamics of n-butanol/water mixture in a single vertical capillary tube with different radii (0.4, 0.6, and 0.85 mm). For liquids, distilled water, n-butanol, and their blends with varying concentrations of butanol (0.3, 0.5, and 0.7 wt.%) were used. The results show that the height and velocity of the capillary rise were dependent on the tube radius and liquid surface tension. The larger the radius and the higher the surface tension, the lower was the equilibrium height (he) and the velocity of rise. The process of capillary rise was segregated into three characteristic regions: purely inertial, inertial + viscous, and purely viscous regions. The early stages (purely inertial and inertial + viscous) represented the characteristic heights h1 and h2, which were dominant in the capillary rise process. There were linear correlations between the characteristic heights (h1, h2, and he), tube radius, and surface tension. Based on these correlations, a linear function was established between each of the three characteristic heights and the consolidated value of tube radius and surface tension (σL/2πr2). [ABSTRACT FROM AUTHOR]

Despite their promise in diverse applications, lubricant depletion over time presents an important challenge for slippery lubricant‐infused porous surfaces (SLIPS). The main source of lubricant depletion is the growth of a wetting ridge around a droplet of foreign liquid that removes the infused lubricant from the porous surface when the droplet slides off. This work describes the fabrication of liquid‐infused ZnO nanowire array by capillary rise lubrication and the effect of array morphology on suppressing wetting ridge formation. The orientation of nanowires strongly affects lubricant infiltration and the stability of SLIPS properties. The infiltrated lubricant in random ZnO nanowire arrays does not form a visible wetting ridge around a water droplet because of the strong capillarity that retains the lubricant confined in the nanoporous structure. The lack of wetting ridge gives rise to a stable SLIPS that exhibits self‐recovery of the infused lubricant. Such a structure retains lubricant under a strong centrifugal force, showing high stability. This study provides a straightforward, robust, and potentially scalable approach for making stable SLIPS that suppresses lubricant depletion by taking advantage of the unique morphology of the random nanowire arrays and capillary rise lubrication. [ABSTRACT FROM AUTHOR]

We consider a classical problem of a capillary neck between a parabolic body and a plane with a small amount of liquid in between. In the state of thermodynamic equilibrium, the contact area between the bodies and the liquid layer has a circular shape. However, if the bodies are forced to slowly move in the tangential direction, the shape will change due to the hysteresis of the contact angle. We discuss the form of the contact area under two limiting assumptions about the friction law in the boundary line. We also present a detailed experimental study of the shape of sliding capillary contact in dependence on the roughness of the contacting surfaces. [ABSTRACT FROM AUTHOR]

In a previous study, a layer of limewash was detected over the gypsum plasterworks used to decorate different spaces of the Real Alcázar of Seville such as interior rooms, patios and outdoor galleries. In this paper its use is analysed, namely whether it improves the properties of the plasterworks and provides a protective effect, through accelerated weathering tests designed specifically to reproduce real environmental conditions. Plaster specimens with similar composition and physical characteristics to those of the original plasterworks were prepared. After the cure of the specimens, the application of a layer of limewash was made. Samples were subjected to weathering tests that consist of water absorption cycles (by capillarity and immersion) and drying. The results showed that the application of limewash did not improve the durability of the plaster significantly, although seemed to have a more protective effect against weathering by capillarity tests in the specimens prepared with a higher water/plaster ratio. In fact, after the immersion tests a great part of the limewash layer became detached, while in the plasterworks of the Real Alcázar this behaviour has not been observed. So, capillarity tests seem to be more adequate to reproduce the real weathering conditions of these ornamental elements. [ABSTRACT FROM AUTHOR]

Gravity-capillary waves at the water surface are an obvious example illustrating wave propagation in the laboratory, and also nonlinear wave phenomena such as wave interactions or wave turbulence. However, at high-enough frequencies or small scales (i.e., the frequencies typically above 4 Hz or wavelengths below 10 cm), the viscous dissipation cannot be neglected, which complicates experimental, theoretical, and numerical approaches. In this review, we first derive, from the fundamental principles, the features of the gravity-capillary waves. We then discuss the origin and the magnitude of the viscous wave. dissipation in the laboratory and under field conditions. We then show that the significant level of dissipation has important consequences on nonlinear effects involving waves. The nonlinearity level quantified by the wave steepness must be large enough to overcome the viscous dissipation. Specifically, using water as fluid in the field and in the laboratory, nonlinear wave interactions and wave turbulence occur most of the time in a non-weakly nonlinear regime, when the waves are in the capillary or gravity-capillary range.

• The limestone of the Cathedral of Cuenca (Spain) is studied. • A methodology for estimation of the material hygric parameters is proposed. • The characterization strategy is based on an inexpensive and undemanding test. • Water absorption test allow to obtain a full hygric characterization. • Statistical analysis of the estimated parameters offers confidence in the strategy. This work analyses the characterization of the hygric behaviour of a stone heritage material by solving the inverse problem using experimental data obtained from a water absorption by capillarity test (EN 15801). This common test is undemanding and requires relatively simple equipment as compared to other hygric characterization tests. For the solution of the direct problem of transient flow in partially saturated porous media, a computational module was developed in COMSOL Multiphysics that includes the conceptual model from the standard EN 15026. The selected material was the heritage stone of the Cuenca Cathedral, differentiating between two characteristic lithotypes: one with greater porosity and another that is more resistant, with more reduced porosity. Based on the experimental results, the intrinsic permeability and the parameters of the moisture storage function are estimated for the two lithotypes. Similarly, contrast tests were conducted to quantify the estimation error. A stochastic analysis was performed to assess if the estimated hygric parameters satisfactorily characterize the behaviour of the studied stone. [ABSTRACT FROM AUTHOR]

This paper is concerned with the time-asymptotic behavior of strong solutions to the initial-boundary value problem of the isothermal compressible fuid models of Korteweg type with density-dependent viscosity and capillarity on the half-line R+. The case when the pressure The case when the pressure p(v) = v, the viscosity (v) = v and the capillarity (v) = v for the specifc volume v(t, x) > 0 is considered, where are parameters, and are given positive constants. We focus on the impermeable wall problem where the velocity u(t, x) on the boundary x = 0 is zero. If and satisfy some conditions and the initial data have the constant states (v+, u+) at infnity with v+, u+ > 0, and have no vacuum and mass concentrations, we prove that the one- dimensional compressible Navier-Stokes-Korteweg system admits a unique global strong solution without vacuum, which tends to the 2-rarefaction wave as time goes to infnity. Here both the initial perturbation and the strength of the rarefaction wave can be arbitrarily large. As a special case of the parameters and the constants the large-time behavior of large solutions to the compressible quantum Navier-Stokes system is also obtained for the frst time. Our analysis is based on a new approach to deduce the uniform-in-time positive lower and upper bounds on the specifc volume and a subtle large-time stability analysis. [ABSTRACT FROM AUTHOR]

The granular column collapse experiment is an important benchmark case for the physical and numerical study of transitional mass flows. Unlike columns of dry granular materials, the presence of a relatively incompressible fluid, such as water, in the voids of saturated columns complicates the shear behavior of the column by becoming a function of the coupled shear and volumetric behavior of the grain–fluid system. Dilative or contractive behavior at the pore level will cause a decrease or increase, respectively, in the pore fluid pressure. These changes in effective stress, in turn, will define stability or instability and length of runout. Here we use the new opportunity provided by transparent soil to observe air entry within saturated columns to explore the hypothesis that the entry pressure provides the maximum contribution of capillary pressure at incipient failure, thereby providing a quantitative control on the stability of dilative granular columns. Furthermore, the mobility of densely packed saturated columns subject to collapse was significantly influenced by air entry. An analytical model, based on this assumption of limiting capillary pressure, is able to describe the stability of the experimental columns as well as the larger dataset from the literature, reframing the previous empirical stability threshold using limit equilibrium and soil material parameters. Our results demonstrate the importance of stress-dilatancy and air-entry phenomena on the rapid shear behavior of saturated granular materials. [ABSTRACT FROM AUTHOR]

Standard predictions induced by the balance of surface tension and pressure dictate that static soap bubbles must be spherical. However, definite non-spherical shapes appear in large bubbles, where noticeable oblate or prolate deformations occur. Gravity is the principal cause of such deformations, and multiple approaches for including its influence appear in recent literature. This paper derives a general surface-theoretic model by applying asymptotic and variational methods to a fully three-dimensional set-up where the soap bubble is a finite-thickness film. The procedure illuminates implicit assumptions, clarifying the discrepancies seen in previous models. Then the model is studied in four physical situations. In three of these situations, results show that there is a maximum stable span and volume of the soap bubbles, implying that their behaviour is qualitatively more similar to liquid drops than standard soap bubbles. Also, the model presented is directly analogous to the two-dimensional version of a hanging chain, and the derived predictions give practical insights into the construction of heavy containment vessels. [ABSTRACT FROM AUTHOR]