Liquid Water Vapor Research Articles

Electromechanics of the liquid water vapour interface.

Two collective properties distinguishing the thin liquid water vapour interface from the bulk liquid are the anisotropy of the pressure tensor giving rise to surface tension and the orientational alignment of the molecules leading to a finite dipolar surface potential. Both properties can be regarded as capillary phenomena and are likely to be coupled. We have investigated this coupling by determining the response of the tangential component of the surface tension to the application of an electric field normal to the surface using finite field molecular dynamics simulations. We find an upside down parabola with a maximum shifted away from zero field. Comparing the molecular dynamics results to a phenomenological electromechanical model we relate the zero field derivative of the tangential part of the surface tension to the electrostatic potential generated by the spontaneous interface polarization. When interpreted with this model our simulations also indicate that Kelvin forces due to electric field gradients at a polarized interface play an important role in the effective dielectric response.

Role of zero point energy in promoting ice formation in a spherical drop of water

We demonstrate that the Lifshitz interaction energy (excluding the self-energies of the inner and outer spherical regions) for three concentric spherical dielectric media can be evaluated easily using the immense computation power in recent processors relative to those of a few decades ago. As a prototype, we compute the Lifshitz interaction energy for a spherical shell of water immersed in water vapor of infinite extent while enclosing a spherical ball of ice inside the shell, such that two concentric spherical interfaces are formed: one between solid ice and liquid water and the other between liquid water and gaseous vapor. We evaluate the Lifshitz interaction energy for the above configuration at the triple point of water when the solid, liquid, and gaseous states of water coexist, and, thus, extend the analysis of Elbaum and Schick in Phys. Rev. Lett. 66 (1991) 1713 to spherical configurations. We find that, when the Lifshitz energy contributes dominantly to the total energy of this system, which is often the case when electrostatic interactions are absent, a drop of water surrounded by vapor of infinite extent is not stable at the triple point. This instability, that is a manifestation of the quantum fluctuations in the medium, will promote formation of ice in water, which will then grow in size indefinitely. This is a consequence of the finding here that the Lifshitz energy is minimized for large (micrometer size) radius of the ice ball and small (nanometer size) thickness of the water shell surrounding the ice. These results might be relevant to the formation of hail in thunderclouds. These results are tentative in that the self-energies are omitted; surface tension and nucleation energy are not considered.

Experimental and numerical study of heat and mass transfer during contact heating of sliced potatoes

Studies concerning the contact heating of food products remain relatively rare in the literature despite the importance of this mode of heat transfer in many operations (grilling, pan-frying).To deal with this, kinetics of product water loss and temperature rise were recorded during contact heating of potato slices in order to examine the influence of the heating power and of the presence or not of an oil layer below the heated product. From the experimental data acquired, a 2D mathematical model based on a moving boiling-front approach was developed and validated allowing the determination of contact heat transfer coefficient values of 512.2 ± 12.4 W m−2.K−1 and 197.5 ± 5.8 W m−2.K−1 for experiments with and without oil respectively. The analysis of the simulation results showed that the overall heating of the product is limited by: (i) the evaporation of liquid water at the location of a boiling front propagating within the heated product and (ii) by the development of a dried region (crust) in the lower part of the product acting as a thermal insulating layer. It should also be noted that the determination of the contact heat transfer coefficient can become an incidental problem (especially for experiments with oil) since the thermal contact resistance is often much lower than the thermal resistance associated with conduction in the dried region of the product.

Convective drying of a moist porous object under the effects of a rotating cylinder in a channel

Numerical study of evaporation in porous medium during convective drying process was examined, and heat and mass transfer of liquid water and water vapor through porous media was investigated by using the Galerkin weighted residual finite element method. The porous moist object has a rectangular shape and is assumed to represent a food sample. Two-dimensional laminar flow of dry hot air was used in the channel with a rotating circular cylinder. Different locations and angular rotational speed of the rotating cylinder were considered to control the convective heat transfer and mass transportation. The radius of rotating cylinder and velocity of drying air were also varied with five different values. Results showed that rotational angular speed and drying air velocity had significant effect on heat transfer and mass transport phenomenon for the porous moist object.

Preliminary exploration of atmospheric water vapor, liquid water and ice water by ultraviolet Raman lidar.

Water is the only atmospheric component with three phases. In this work, ultraviolet Raman lidar is developed for synchronous measurements of water vapor, liquid water and ice water in Xi'an (34.233°N, 108.911°E), China. Different interference filters are designed to construct individual water Raman channels, and the corresponding central wavelength and bandwidth are determined by 399.0 nm (3.1 nm), 403.0 nm (5.0 nm) and 407.6 nm (0.6 nm) in ice water, liquid water and water vapor Raman channels, respectively. The mutual interference effect originating from the overlapping characteristics of water Raman spectra is further analyzed, and an accurate retrieval method based on linear simultaneous equations and mutual interference degrees is proposed for synchronous three-phase water mixing ratio profiles. Preliminary measurements are carried out in the Centre for lidar remote sensing research of Xi'an University of Technology, and representative measurement examples are obtained and validated for the performance of the Raman lidar system. Synchronous mixing ratio profiles in water vapor, liquid water and ice water are retrieved, and the corresponding extinction coefficient and relative humidity profiles are also combined to reveal the variation characteristics in three-phase waters. The possible aerosol fluorescence are analyzed as well, and it is inferred that the aerosol fluorescence might affect (possibly overestimate) the derived mixing ratio values of the liquid water and ice water. The effective detection can reach up to a height of 5 km under cloudy weather, and synchronized growth in water vapor and liquid water content is obtained in cloud layers. Continuous observations are also made under hazy weather conditions, and the temporal and spatial evolution trends of three-phase waters in clouds are successfully realized. Preliminary exploration and results validate the feasibility of ultraviolet Raman lidar for synchronous measurements of atmospheric water vapor, liquid water and ice water.

The effects of elastane and finishing properties on wicking, drying and water vapour permeability properties of denim fabrics

PurposeThe liquid water and water vapour transfer properties of fabrics play an important and decisive role in determining thermal comfort properties of clothing systems. The purpose of this paper is to analyse the effects of fabric composition (98 percent cotton–2 percent elastane and 100 percent cotton) and finishing treatments (rigid, resin, bleaching and softening) on the wicking, drying and water vapour permeability (WVP) properties of denim fabrics.Design/methodology/approachThe research design for this study consists of experimental study. Two fabric compositions (98 percent cotton–2 percent elastane and 100 percent cotton) and four finishing treatments (rigid, resin, bleaching and softening) were evaluated to see the effects of elastane and finishing treatments on wicking, drying and WVP properties of woven denim fabrics. Results were analysed statistically.FindingsExperimental results showed that the transfer wicking, drying and WVP values of denim fabrics were significantly influenced by fabric weight, fibre composition and finishing treatments.Practical implicationsThe wicking ability of sweat from the skin to the outer environment of a skin contact fabric layer is the primary requirement.Originality/valueAs a result of the literature review, it was seen that there are some studies in the literature about comfort properties of denim fabrics, but there is no study concerning the water vapour transmission, wicking and drying properties of denim fabrics.

Improved Algorithms for the Measurement of Total Precipitable Water and Cloud Liquid Water from SARAL Microwave Radiometer Observations

SARAL carried onboard a radar altimeter that provides very precise measurements of the sea surface height (SSH). Like other altimetric missions, SARAL carries a passive microwave radiometer (PMR) for wet tropospheric correction to SSH. In the present study, new algorithms are developed for the retrieval of cloud liquid water (CLW) and total precipitable water vapor (TPW) over the global oceans from PMR measurements of the brightness temperatures. A radiative transfer and genetic algorithm based retrieval scheme is proposed for the estimation of CLW and TPW from SARAL PMR. The comparisons of CLW from PMR with independent measurements from GPM-GMI and SSMIS within and outside ±40° latitudes show correlation (R) of 0.86 and 0.83, bias of 0.7 and −3.61 mg/cm2, and root mean square error (RMSE) of 8.42 and 8.07 mg/cm2, respectively. Similarly, TPW from PMR with GPM-GMI and SSMIS show R of 0.99 and 0.98, bias of −0.04 and −0.03 g/cm2 and RMSE of 0.17 and 0.17 g/cm2, respectively. The retrieval accuracy of CLW and TPW from the new algorithms is compared with these parameters provided in the SARAL geophysical data records as finished products, which showed substantial improvement in the quality of the parameters from the new algorithm.

Steady-state analysis of heat–moisture–salt coupling in unsaturated layered soil

Based on the theory of porous media, the multifield coupling problem of heat–moisture–salt in unsaturated layered soil under the steady condition is studied considering that the pore of unsaturated soil is filled with liquid water, dissolved salt, water vapour and dry gas. Based on the conservation of mass and energy equations, the paper discusses the mass conservation equations and energy conservation equations for water, gas and salt in unsaturated soils. Considering the one-dimensional steady-state problem, the state equations are obtained by selecting temperature, pore air pressure, pore water pressure and salt solution concentration and their derivatives as the state variables. Under the condition of the boundary values of adjacent soil layers in a given unsaturated soil, the non-linear variable coefficient differential equations are solved by using the shooting method and the validity of the model is verified by comparing with existing steady-state experimental results. Based on numerical examples, the differences in temperature field, pressure field and salinity field between unsaturated layered soil and homogeneous soil are analysed.

Calculation of Equilibrium Thermobaric Parameters for the Formation or Dissociation of Hydrates of Multicomponent Gases

An original method for calculating the equilibrium pressure for the formation or dissociation of multicomponent gas hydrates as a function of temperature and composition has been developed. It is applicable to gas and water systems that are in the following phase states: gas–water vapor–ice; gas–water vapor–liquid water. The developed method is suitable for determining the equilibrium conditions for the formation (dissociation) of hydrates of multicomponent gases depending on their composition with an accuracy of about 1%. The novelty of the developed method is protected by a patent of the Russian Federation.

Effect of aggregate size and inclusion of polypropylene and steel fibers on explosive spalling and pore pressure in ultra-high-performance concrete (UHPC) at elevated temperature

This paper investigates the individual and combined effects of polypropylene (PP) fibers, steel fibers, and aggregate size on spalling behavior and pore pressure build-up of ultra-high-performance concrete (UHPC) exposed to elevated temperature. Simultaneous measurements of pore pressure and temperature were conducted at different depths in UHPC specimens under one-sided heating with a heating rate of 2 °C/min. Compressive, tensile, and permeability tests were performed to analyze spalling behavior. Addition of PP fibers fully prevented spalling and they are much more effective in increasing permeability than steel fibers and larger aggregates. The combined use of PP and steel fibers, and PP fibers and larger aggregates showed strong synergistic effect on increasing permeability. The higher the permeability, the lower was the maximum pore pressure measured in the samples. Two plateaus were observed from the temperature history due to vaporization of liquid water (between 115 and 125 °C inside the specimens) and release of water vapor (starting from 180 °C), respectively. The second plateau was identified as the functional temperature of PP fibers. Maximum pore pressures in spalled specimens were much lower than their tensile strengths, which could imply the contribution of hydraulic pressure in the region of moisture clog on spalling.

Numerical test of the laboratory evaporation method using coupled water, vapor and heat flow modelling

Laboratory evaporation experiments are used to determine soil hydraulic properties (SHP). In most cases, data are evaluated with the simplified evaporation method (SEM). Numerical simulations were used before to quantify the accuracy of the SEM and it was found that the method yields accurate estimates of SHP. However, previous tests neither accounted for heat flow, nor thermal fluxes of liquid water and water vapor, nor temperature effects on the transport properties. Since evaporation experiments are under most circumstances non-isothermal, past studies were therefore oversimplified and likely inaccurate. The objective of this article is to test the accuracy of the SEM using numerical simulations with a coupled model of water, vapor, and heat flow which is based on the Philip-de Vries theory and solves the surface energy balance. The model provides a state-of-the-art description of the fluxes of water, vapor and energy during laboratory evaporation from bare soil. We present simulation results for different soil textures and resistances to vapor flow between soil and air, and analyze the accuracy of the SEM using the simulated data. The resulting average error for the water retention curve is smaller than 0.0025 m3 m−3 and the relative error of hydraulic conductivity ranges from 5 to 15% for sandy loam and clay loam. For sand, the error in conductivity is higher but the structural shape of the conductivity curve is still identified relatively well. Compared to previous analyses of the evaporation method assuming isothermal flow, the average error of the SEM turned out to be only slightly higher.

Changes in moisture performance of wood after weathering

After the durability of wood against wood decay fungi, its water performance is the next most important factor that influences the performance of wood in outdoor, above-ground applications. It is therefore of major importance to optimize methods that are able to predict the moisture behaviour of wood in outdoor applications. In order to elucidate these questions, samples were prepared from European oak (Quercus robur/Q. petraea), sweet chestnut (Castanea sativa), European larch (Larix decidua), Scots pine heartwood and sapwood (Pinus sylvestris), Norway spruce (Picea abies) and beech (Fagus sylvatica). The moisture performance of the samples was altered by thermal modification, wax, oil and biocide treatment. Two types of specimens were prepared; smaller specimens (1.5 × 2.5 × 5.0 cm) were exposed to natural weathering for three periods (9, 18 and 27 months) and subsequently analyzed in the laboratory with various methods (contact angle, short- and long-term water uptake and water vapor uptake). In parallel, bigger specimens (2.5 × 5.0 × 50 cm) were exposed outdoors in a monolayer exposure and equipped with moisture monitoring sensors for 18 months. Water performance of wood could change as a result of weathering, being the most evident at thermally modified wood, where the decrease of the moisture performance was the most evident. The results of the study clearly showed that the water performance of the majority of the materials decreased with natural weathering. These results indicate that in order to elucidate the moisture performance of wood fully, a variety of laboratory tests needs to be applied, relating to both liquid water performance and water vapour interactions with wood.

Green Synthesis of Low‐Dimensional Aluminum Oxide Hydroxide and Oxide Using Liquid Metal Reaction Media: Ultrahigh Flux Membranes

AbstractLiquid metal reaction media provides exciting new avenues for synthesizing low‐dimensional materials. Here, the synthesis of atomically thin sheets and nanofibers of boehmite (γ‐AlOOH) and their transformation into cubic alumina (γ‐Al2O3) via annealing is explored. The sheets are as thin as one orthorhombic boehmite unit cell. The addition of aluminum into a room temperature alloy of gallium, followed by exposing the melt to either liquid water or water vapor, allows growing either 2D sheets or 1D fibers, respectively. The isolated oxide hydroxides feature large surface areas, with the sheet morphologies also showing a high Young's modulus. The method is green, since the liquid metal solvent can be fully reused. The ultrathin boehmite sheets are found suitable for the development of freestanding membrane filters that enable excellent separation of heavy metal ions and oil from aqueous solutions at extraordinary filtrate flux. The developed liquid metal‐based synthesis process offers a sustainable, green, and rapid method for synthesizing nanomorphologies of metal oxides which are challenging to obtain by conventional methods. The process is both sustainable and scalable and may be explored for the creation of other types of metal oxide compounds.

Diagenesis in Mesozoic carbonate rocks in the North Pyrénées (France) from mineralogy and fluid inclusion analysis: Example of Rousse reservoir and caprock

Fluid-rock interaction is of key interest for deciphering the geodynamic history of complex geological environments. In this paper, we describe the mineralogy and petrography of the Rousse reservoir (the Upper Jurassic “Dolomie de Mano” formation) as well as the reconstruction of its thermal and pressure history. We also investigate the base of the reservoir caprock (the Campanian breccia). A satellite of the giant gas field of Lacq in the south-west of France, Rousse was a gas producer until it moves to a CO2 storage site in 2010. Rousse is located within a deep, isolated, faulted, carbonate Jurassic horst overlain by a 4500 m thick overburden that is composed of a series of turbiditic flysch deposits of Upper Cretaceous (Cenomanian) to Tertiary (Eocene) age. Cores were sampled from two wells, Rousse 1 and 2, and were analyzed by ICP-MS, XRD, SEM, EPMA, TEM, cathodoluminescence and fluid inclusion techniques. Pressure-Temperature (P-T) conditions were derived by modeling data from fluid inclusions trapped in the fracture minerals of the “Dolomie de Mano” formation and the Campanian breccia. In the “Dolomie de Mano”, diagenesis was dominated by three dolomite episodes followed by a calcite stage in fractures. The second and third dolomitizations were associated with fracturing episodes. These dolomites precipitated from low-saline (<1 mol·kg−1 eq. NaCl) hydrothermal fluids at temperatures around 150 °C. These two characteristics exclude dolomitization during a synsedimentary slope brecciation event and also the role of hypothetical secondary brines. In the Campanian breccia, dolomitization is marginal and the main precipitation is calcite. In association, two types of fluid inclusion (liquid water-vapor and vapor) can be distinguished in the two formations and are marked by predominant CH4 and variable CO2 contents. The presence of gas inclusions in the reservoir as in the caprock is indicative of several gas invasions. A P-T modeling of the geologic evolution of the area reveals two periods of fluid circulation: a first stage (150–170 °C, 20 MPa) during the Late Jurassic to Early Cretaceous for the reservoir rock, corresponding to the rifting period of the North-Pyrénées western zone; and a second stage (170 °C, 41 MPa) during the late Eocene period in breccias, corresponding to the Pyrenean compression period. The petrophysical properties of the reservoir, marked by an intense fracture network, were acquired early during an extensional period, whereas the impact of fluids associated with a period of compression appears to have been limited in space to drainage of tectonic origin. Finally, we note significant similarities between the petrographic and fluid signatures of the Chaînons béarnais, in the folded orogenic wedge located south of the North Pyrenean Frontal Thrust, and Rousse, located in the foreland basin to the North. Nevertheless, the temperature recorded in the Chaînons béarnais reached 300–350 °C, much higher than in Rousse due to its position in the vicinity of an over-thinned palaeomargin during the early Cretaceous.

Deterioration caused by dimensional change in stone (EBD pathology): the role of the organic matter — pore network — salt combination

Abstract We have studied a pathology produced by dimensional changes in Miocene lacustrine limestones of the Ebro basin with very low clay content (Briviesca and Tudela stone). The samples studied come from stone blocks of the Cathedrals of Burgos and Tudela and their respective original quarries. Three additional rocks that present a pattern of similar deterioration are also characterised. The pathology, known as “Expansion by Drying (EBD)”, looks like a mechanical fracture and is produced by important dimensional changes of the material. We have carried out a detailed study of the rocks with Mercury Intrusion Porosimetry (MIP) and establish four different porous systems in the materials studied. A relationship is found between the type of porous system and the presence of the pathology. In order to develop, EBD pathology needs a porosimetry like the one defined for group IV. On the other hand, oxidation of the organic matter present in the rock (proven by aging the rock with ozone) changes the porosimetry of group IV rocks, converting them into a porous network of group III. These facts explain why EBD pathology develops in oxidized rocks of historical buildings and not in fresh quarry rocks. In addition, we characterise dimensional changes of the rock by the intrusion of liquid water (conventional hydric expansion) and water vapour adsorption. These data have been relevant to understand the mechanisms of the dimensional change in the rocks studied.

Transport Rate of Liquid Water and Saturated Water Vapors across Polymer Proton-Exchange Membranes

Dependences of the transport rate of liquid water and saturated water vapor across commercial membranes (Nafion, MF-4SK) and proton-exchange membranes synthesized by the authors (PVDF, PP, UHMWPE, PTFE films modified with sulfonated polystyrene) on the membrane thickness have been studied. It has been found that at room temperature (17–25°C), the transport rate of liquid water and saturated water vapor across the membranes into an air stream hardly depends on the membrane type and thickness (60–240 μm), with the transport rate of saturated vapor being almost an order of magnitude below that of liquid water contacting one of the membrane surfaces. The fact that the flux of water and water vapor across the membrane does not depend on membrane thickness under conditions of maximum moistening suggests that the flow resistance is determined by the resistance at the feed and permeate interfaces. If one of the membrane surfaces is in contact with liquid water, the transport rate is equal to the rate of water removal from the permeate surface of the membrane; in the case of contact with saturated vapor, the transport rate is determined by the rate of water sorption from the vapor phase by the membrane. The results can be used to optimize the operation of fuel cells based on polymer proton-exchange membranes.

WATER PERMEABILITY OF EXTERIOR WOOD COATINGS: WATERBORNE ACRYLATE DISPERSIONS FOR WINDOWS

Permeability of coatings for water and water vapor is an important factor in their wood protective function. In this study, the permeability of coatings in terms of liquid water and water vapor absorption and desorption was measured based on different parts of the standard EN 927. This study evaluated the permeability of commercial coating systems and ascertained effects of coating layering on the coating permeability. For this measurement, six different waterborne acrylate dispersions were used as paint on spruce test samples. The results clearly revealed that liquid water and water vapor uptake were affected by coating film thickness, number of coats, and coating composition (producer). It was ascertained that the type of coating pigmentation affected water absorption of coatings and that with a constant coating film thickness, the number of coats affected water vapor absorption and desorption, but not water absorption. Furthermore, it was observed that the number of coats affected the correlation between the coating film thickness and water vapor absorption and desorption. The values for water vapor absorption were much higher than for liquid water absorption and, unlike the water vapor absorption rate, the water vapor desorption rate was approximately 50% lower.

Methane Hydrate Formation and Dissociation in Synperonic PE/F127, CTAB, and SDS Surfactant Solutions

Formation and dissociation conditions for methane hydrates were investigated in the presence of aqueous solutions of a no-ionic triblock copolymer synperonic PE/F127 (PE/F127) at 377, 710, 1530 ppm with the aim of evaluating the promotion activity. A cationic cetyltrimethylammonium bromide (CTAB) and an anionic sodium dodecyl sulfate (SDS) surfactant were also tested and conducted at 356, 705, 1500 ppm and 376, 701, 1510 ppm respectively. Experiments with the three surfactants were carried out in an isochoric autoclave under the same conditions: near the ice normal melting point (273.15 K), as the cooling temperature of the autoclave, and five initial pressures stated from 3.5 to 12.0 MPa. Performance of these surfactants was assessed by reporting hydrate–liquid water–vapor (H–L–V) phase equilibria, enthalpies of dissociation estimated using the Clausius–Clapeyron equation, induction times, crystallization temperatures, growth rates and theoretical methane consumptions. In brief, the obtained induction time for PE/F127 was higher than CTAB but lower than SDS, the growth rate between PE/F127 and SDS were similar at lower concentrations, and the maximum gas consumption for PE/F127 was reached at 1530 ppm but this methane uptake was far from those results using SDS.

Cellulose nanocrystal/amino-aldehyde biocomposite films

From the suspensions of cellulose nanocrystals (CNCs) derived from cotton and flax by acidic hydrolysis, transparent and smooth films were produced with different plasticizers and an amino-aldehyde based cross-linking agent in a wide composition range by a simultaneous casting and wet cross-linking process. The effect of cross-linker concentration on the optical and tensile properties and on the morphology of CNC films was investigated by various measurements. The interaction of films with liquid water and water vapour was also characterized by water sorption and water contact angle as well as performing a sinking test. Cross-linking improved the transparency, reduced the porosity and surface free energy, and prevented the delamination of CNC films in water at a concentration of 10% or higher. The surface of CNC films is basic in character and has an electron donor property. The CNC/amino-aldehyde films had a high tensile strength (45 MPa) and modulus (11 GPa).

Three-Body Hydrogen Bond Defects Contribute Significantly to the Dielectric Properties of the Liquid Water-Vapor Interface.

We present a simple model of aqueous interfacial molecular structure, and we use this model to isolate the effects of hydrogen bonding on the dielectric properties of the liquid water-vapor interface. We show that water's interfacial molecular structure can be understood by considering the orientational preferences of a single molecule immersed in the environment of the average interfacial density field. We illustrate that depth-dependent orientational anisotropy is determined by the geometric constraints of hydrogen bonding, and we show that the primary features of atomistic simulation data can be reproduced by assuming an idealized, perfectly tetrahedral hydrogen bonding geometry. We demonstrate that nonideal hydrogen bond geometries are required to account for variations in the orientational polarization and polarizability of the interface. Finally, we highlight that these properties contain significant contributions from a specific type of geometrically distorted three-body hydrogen bond defect that is preferentially stabilized at the interface.