Internal Water Content Research Articles

Influence of internal water phase gelation on the shear- and osmotic sensitivity of W/O/W-type double emulsions

It has already been hypothesized and in some cases proven that gelation of the internal water droplets of W/O/W-type double emulsions might allow the application of a higher shear in the second emulsification step while maintaining a high internal water content. In this contribution, thermal denaturation of a concentrated whey protein isolate solution, which is used as the internal water phase, was investigated. Low-resolution NMR T2-relaxometry measurements (using a CPMG-sequence) clearly showed that this thermal treatment effectively gelled the internal water phase. Using this approach, double emulsion droplets with a small average diameter (D43 of about 5 μm) and narrow particle size distribution were produced while a high internal water content was maintained. Moreover, our results indicated that gelation could not prevent osmotic shrinking of the double emulsion droplets upon dilution in hypertonic solution. However, gelation of the internal water phase clearly reduced the degree of osmotic swelling of the double emulsion droplets upon hypotonic dilution. However, this effect is probably due to droplet-globule coalescence occurring at lower internal water volume increases in case the internal water phase is gelled.

Effect of the water content measurements on the estimation and identifiability of water diffusion and convection mass transfer coefficients

The aim of this work was to determine the impact of water content measurements on the structural and practical identifiability of the diffusion and the convection mass transfer coefficients. Global or internal water content were generated from the diffusion model with the addition of Gaussian noise. The diffusion and convection mass transfer coefficients were estimated from the water content by least-squares minimization and their confidence interval was calculated using the profile likelihood and the asymptotic methods. A unique combination of mass transfer coefficients reproduced exactly water content values without noise, indicating their structural identifiability. The coefficients were practically identifiable from the internal water content or the global water content if the noise intensity was less than 2% and 5%, respectively. The confidence intervals of the coefficients were asymmetric and were not accurately described by the asymptotic method.

Neutron scattering and imaging: a tool for archaeological studies

Neutron scattering and neutron imaging are powerful techniques for studying the structure of objects without damage, which is an essential prerequisite for investigations in Cultural Heritage domain, particularly in Archaeology. The deep penetration of neutrons in most materials allows for the study of relatively large objects. The contrast between similar materials, like metals in alloys, or that due to the presence of hydrogen atoms gives information about the internal structure of objects that have been modified or repaired in the past. Imaging and tomography give a 3-dimensional view of the whole object, permitting discrimination between different parts of the object, voids, water content and large pores. Neutron scattering also provides information about elemental composition as well as about tiny pores and quantitative evaluations of the total area of internal surfaces or water content. The paper is an introduction to these techniques, which are easily accessible at neutron facilities.

On Water Transfer and Hydraulic Connection Layer During the Convective Drying of Rigid Porous Material

Theconvectivedryingofanaturalporousmaterial,limestone,isinvestigatedinthis study, with both experimental and numerical approaches. The first experimental campaign, which focuses on the influence of samples' slenderness, suggests the presence of a hydraulic connection layer between the porous water and the external environment, in spite of the very fine pore structure of the material. This hydraulic transfer enables the fast water evaporation at the beginning of the drying test, when external conditions drive the kinetics. Furthermore, the results show that this layer does not exceed 30 mm deep from the external surface, given the drying conditions of the test. A second experimental campaign aims to analyse, by mean of an X-ray tomography tool, the internal water content during the drying. It confirms that water transfer takes place within the limestone in two distinct stages. The first stage being faster than the second one with a homogeneous desaturation along the sample, it is consistent with the hypothesis of the hydraulic connection layer. Finally, the finite element modelling makes possible to identify the main mechanisms of water transfer, namely liquid convection and vapour diffusion.

Delimiting water in the chromium-induced stabilization of collagen

Abstract Industrial processes, such as stabilization of skin matrix using chromium, often consume huge quantity of water resulting in depletion of globally demanded valuable resource. Nevertheless, water is essential for the hydrolysis, diffusion, distribution and fixation of chromium in the collagen matrix. Although greener and sustainable solutions for this industrially important process can be obtained through the use of green solvent such as ethanol, probing the minimum quantity of water required for the chromium-induced stabilization of collagen matrix is defied for several years. Here, we show that a minimum of 55–65% internal water content within the collagen matrix is necessary for making chrome tanned leathers through lyophilization technique. The amount and distribution of chromium in the leather decreases as a linear function of internal water content in the skin matrix (from 65 to 15%) with increasing lyophilization time as demonstrated through optical and electron microscopic analyses coupled with energy dispersive x-ray microanalysis.

Expansive soil crack depth under cumulative damage.

The crack developing depth is a key problem to slope stability of the expansive soil and its project governance and the crack appears under the roles of dry-wet cycle and gradually develops. It is believed from the analysis that, because of its own cohesion, the expansive soil will have a certain amount of deformation under pulling stress but without cracks. The soil body will crack only when the deformation exceeds the ultimate tensile strain that causes cracks. And it is also believed that, due to the combined effect of various environmental factors, particularly changes of the internal water content, the inherent basic physical properties of expansive soil are weakened, and irreversible cumulative damages are eventually formed, resulting in the development of expansive soil cracks in depth. Starting from the perspective of volumetric strain that is caused by water loss, considering the influences of water loss rate and dry-wet cycle on crack developing depth, the crack developing depth calculation model which considers the water loss rate and the cumulative damages is established. Both the proposal of water loss rate and the application of cumulative damage theory to the expansive soil crack development problems try to avoid difficulties in matrix suction measurement, which will surely play a good role in promoting and improving the research of unsaturated expansive soil.

Research on Shear Strength of Compacted Loess

Compacted loss widely used in the construction, such as embankment, dam, foundation backfill and other projects. Influenced by rainfall factors, the moisture content of compacted loess often vary so the shear strength will also changed. This paper studies the shear strength parameters of compacted loess through direct shear tests. In the dry density under the same conditions, the cohesion, internal friction angle of compacted loess decreases with the increase of water content. Summed cohesion and water content showed a quadratic parabola and internal friction angle and water content was also found quadratic parabola; further considering the effects of water content and dry density of compacted loess got shear strength formula. Shear strength formula.

Smart Hydrogels Developed with Inter-Crosslinking Network (ICN) Structure

Hydrogels have low frictional properties, permeability and biocompatibility thanks to their high water content. However the problem of common gels is their brittleness as industrial materials. In the last decade, several high-strength gels have been developed, promising for applications of gels as new smart industrial materials. Here we study the smartness of novel ultrahigh ductile gels having Inter-Crosslinking Network (ICN), focusing on mechanical properties and structure. Three types of mesh densities of the ICN gels were experimentally determined from the size of internal structure, water content and Young's modulus of tensile test. By comparing the three mesh densities, the relation between the network structure and mechanical properties of the gels is possibly discussed. The new way to evaluate the ductility of the ICN gels was also introduced on the analogy of the small-world network model. The effect of the degree of polymerization on the ductility was discussed.

Moment analysis description of wetting and redistribution plumes in wettable and water-repellent soils

Summary Water repellency has a significant impact on water flow patterns in the soil profile. Transient 2D flow in wettable and natural water-repellent soils was monitored in a transparent flow chamber. The substantial differences in plume shape and spatial water content distribution during the wetting and subsequent redistribution stages were related to the variation of contact angle while in contact with water. The observed plumes shape, internal water content distribution in general and the saturation overshoot behind the wetting front in particular in the repellent soils were associated with unstable flow. Moment analysis was applied to characterize the measured plumes during the wetting and subsequent redistribution. The center of mass and spatial variances determined for the measured evolving plumes were fitted by a model that accounts for capillary and gravitational driving forces in a medium of temporally varying wettability. Ellipses defined around the stable and unstable plumes’ centers of mass and whose semi-axes represented a particular number of spatial variances were used to characterize plume shape and internal moisture distribution. A single probability curve was able to characterize the corresponding fractions of the total added water in the different ellipses for all measured plumes, which testify the competence and advantage of the moment analysis method.

Effect of Curing Condition on Structure and Scaling Resistance of Specified Density Concrete

Influence of curing condition on internal relative humidity (IRH) of specified density concrete with different w/b ratios, pore structure of cement paste, hydrated product as well as scaling resistance of concrete were investigated. The results show that, as for concrete with w/b ratio of 0.31, water and standard curing can stop or slow up the migration of internal water, and the structure of cement paste is dense due to good hydrated environment, so the scaling resistance of concrete is best; as for concrete with w/b ratio of 0.47, the IRH of concrete under natural curing condition at 28 days is still 90%, there is sufficient water for the hydration of cement, and internal water content of concrete is lower as compared to concrete under water and standard curing conditions which makes it less easy to saturate, so natural curing concrete has better scaling resistance.

Monitoring of Water Content in Building Materials Using a Wireless Passive Sensor

This paper describes an innovative design of a wireless, passive LC sensor and its application for monitoring of water content in building materials. The sensor was embedded in test material samples so that the internal water content of the samples could be measured with an antenna by tracking the changes in the sensor’s resonant frequency. Since the dielectric constant of water was much higher compared with that of the test samples, the presence of water in the samples increased the capacitance of the LC circuit, thus decreasing the sensor’s resonant frequency. The sensor is made up of a printed circuit board in one metal layer and water content has been determined for clay brick and autoclaved aerated concrete block, both widely used construction materials. Measurements were conducted at room temperature using a HP-4194A Impedance/Gain-Phase Analyzer instrument.

A review of water contents of nominally anhydrous natural minerals in the mantles of Earth, Mars and the Moon

Olivine, pyroxene and garnet are nominally anhydrous but can accommodate tens to hundreds of parts per million (ppm) H 2O or “water” in the form of protons incorporated in defects in their mineral structure. This review concerns the amount of water in nominally anhydrous minerals from mantle and mantle-derived rocks: peridotites, eclogites, megacrysts, basalts and kimberlites. Trends between internal and external parameters and water content in olivine, pyroxene, and garnet of mantle rocks allow us to identify what controls their H intake. The water content of pyroxenes and garnets in peridotites appears to depend primarily on mineral chemistry, while that of olivines may more readily reflect water activity and water fugacity conditions in the mantle. In eclogites, both mineral chemistry and metamorphic pressure control the water intake of pyroxene and garnet. The water content of minerals in crystallized melts (basalt and kimberlite phenocrysts, xenocrysts, and megacrysts) is determined by the degree of differentiation, the amount of water in the parent melt, and degassing. Basalt and cumulate minerals from Martian meteorites may be as water-rich as their Earth equivalents. No water has been detected at present in Moon minerals but low amounts in degassed basaltic glasses signify that deep Moon reservoirs may still retain water. The presence of water in mantle minerals, typically amounts of tens to hundreds of ppm, enhances their deformation properties. Water contents of peridotite minerals in the oceanic upper mantle, in and around cratons, and in subduction zones may have tremendous influence on Earth's geodynamics.

Efficiency analysis of reduction and stabilization of biodegradable waste using an aerobic stabilization system

The reduction and stabilization of biodegradable waste were studied using three operational stages in an aerobic stabilization system. The system used for mechanical/biological treatment utilized two-shaft screws in multiple box reactors. In the first operational stage, 50-kg batches of biodegradable waste were charged in each of the three reactors, with peat moss used as a bulking agent. Analysis revealed that peat moss can be used at this initial stage, based on the observed increase in temperature and carbon dioxide levels. The second stage of operation involved adding 100 kg/day of biodegradable waste to the first reactor. It was confirmed that a continuous reaction is possible by the addition of more waste. In the third stage of operation, 20 kg/day of the 100 kg/day of biodegradable waste feed was replaced with material fed back from the third reactor. At this stage, final product was also removed from the third reactor. The temperature was not controlled, and up to 8%–9% carbon dioxide was formed, enabling normal activation of decomposition. This three-stage operational test confirmed the expected decomposition of organic matter and biodegradable materials. The rate of mass reduction calculated for the final product compared with the input amount was 94.3%, which confirmed that this system would be a useful means for the reduction and stabilization of biodegradable waste. This study also measured the water content of the material in the reactors: the water content decreased as the reaction progressed. This indicated that the activation of microorganisms did not occur sufficiently in the second and third reactors. Future studies of methods to control the internal water content of each reactor should improve the decomposition efficiency.

Water content of hair and nails

Water content plays an essential role in human keratinized tissues such as hair and nails. However, daily routines impair the keratin structure of hair and nails, inducing a decrease in their water content. A new methodology for the determination of the internal and external water content of keratinized tissues was optimized. The water content of untreated human hair and nails was studied. Results showed differences in the water content between hair fibers and nails. Furthermore, hair and nails were subjected to a number of treatments and the water content was determined. Evaluation of the moisture content in treated hairs showed that chemical treatments damaged hair fibers, resulting in a pronounced decrease in their external water content. However, the chemical treatments of nails impaired their integrity and led to a decrease in the internal water content.

Novel PVP/PVA hydrogels for articular cartilage replacement

Poly(vinyl alcohol) (PVA) hydrogel has been considered as a very interesting and promising material for articular cartilage replacement. The most vital shortcoming of PVA hydrogels is that their mechanical properties are difficult to meet the requirements of articular cartilage. In the present work, blend hydrogels based on PVA and poly (vinyl pyrrolidone) (PVP) were prepared by repeated freezing and thawing method. Such hydrogel had similar internal three-dimensional structure and water content (approximately 75%) as nature articular cartilage. The mechanical and tribological properties were investigated to find out that change of mechanical and tribological properties of PVP/PVA hydrogels were significantly dependent on PVP content and freezing–thawing cycles. The blend hydrogel with 1 wt.% PVP had the best mechanical properties and the friction system consisting of such blend hydrogel and stainless steel ball exhibited a mixed lubrication regime especially under bovine serum lubrication. The results established that such hydrogel would be a novel attractive material for articular cartilage replacement.

Effects of Dew on the Radiometric Signal of a Grass Field at L-Band

The future Soil Moisture and Ocean Salinity satellite time of overpass is 6 A.M. and 6 P.M. at the equator. In many regions, morning dew is expected at the time of the satellite overpass and might play a role in soil moisture retrievals. The aim of this study was to assess the effects of dew on L-band measurements. Radiometric, biomass, and dew measurements were performed over a natural grass field. Our results show that at the diurnal scale, vegetation internal water content changes play a major role in emission. A direct impact of dew on measurements was not identified. However, a brightness temperature increase of 0.5 and 1 K was observed at vertical and horizontal polarizations, respectively. This increase was detected later after dew, suggesting that it was not directly caused by the presence of dew on the grass blades. Our hypothesis is that the observed increase in brightness temperatures is due to the absorption of dew water by the litter layer.

A Wireless, Passive Embedded Sensor for Real-Time Monitoring of Water Content in Civil Engineering Materials

A wireless, passive embedded sensor was applied for real-time monitoring of water content in civil engineering materials such as sands, subgrade soils, and concrete materials. The sensor, which comprised of a planar inductor-capacitor (LC) circuit, was embedded in test samples so that the internal water content of the samples could be remotely measured with a loop antenna by tracking the changes in the sensor's resonant frequency. Since the dielectric constant of water was much higher compared with that of the test samples, the presence of water in the samples increased the capacitance of the LC circuit (capacitance of the capacitor was proportional to the dielectric constant of the medium between its electrodes), thus decreasing the sensor's resonant frequency. Using the described sensor, a study was conducted to investigate the drying rate of sand samples of different grain sizes. A study was also conducted to measure the curing rate of a portland cement concrete slab during casting, and its drying rate after it has been soaked in water. The described sensor technology can be applied for long-term monitoring of localized water content inside soils and sands to understand the environmental health in these media. In addition, this sensor will be useful for monitoring water content within concrete supports and road pavements. The measurement of water content is important for civil engineering infrastructure since excess water may hasten their degradation.

Research on Formation Mechanism of the Debris Flow on Slope Induced by Rainfall

Based on field investigation and lab tests, rock and soil fracture criterion, and analyses of typical debris flows on slope, the formation mechanism of the rainfall-induced debris flow on slope have been studied by considering its influential factors, kinematics properties, dynamic conditions, and formation and evolution process of the debris flow on slope. The research results indicate that the debris flow on slope is mainly of the type of translational slide failure, which is developed on the steep slope, where gradient is more than 40° with shallow residual soil (thickness is less than 2.0 m). The rainfall is one of the important factors inducing the debris flow on slope. Rainwater penetration makes the residual soil saturate and soften. When water content of the residual soil is more than 28%–30%, the relation curves of cohesion and internal friction angle versus water content show obvious inflexion. That is, when the saturation of the residual soil is more than 75%, the cohesion and internal friction angle both decrease rapidly. The soil on slope will change from stable to destructive. The residual soil will start to form partly mollisol and slip down the slope if it meets persistent rainfall or rainstorm. Further, the sliding soil mass rushes down to create mud slurry-debris flow on slope.

Development of a hydraulic conductivity apparatus for bentonite soils

Measurement and interpretation of hydraulic conductivity in porous media is a complicated process, and many laboratory apparatuses exist for different soil types and conditions. To use models for interpretation and prediction of hydraulic conductivity, accurate test measurements are required. A new hydraulic conductivity apparatus is presented that includes simultaneous control of volume and stress states. The apparatus includes the ability to automatically control volume to apply selected displacement boundary conditions while imposing radial flow conditions. The capabilities of the system are displayed using two selected hydraulic conductivity tests on an unsaturated sand–bentonite mixture, which is a swelling soil. Hydraulic conductivity on the order of 10−13 m/s was measured using the new system and compared closely with previously measured values using a similar material. Post-test measurements displayed internal water content, density, and saturation changes that occurred during testing.

Photosynthetic Patterns of 3 Crassulacean Plants under Drought Conditions

Higher plants can be categorized as C3, C4 or CAM according to their photosynthetic pathways, and some succulent plants are known to shift their patterns of photosynthesis from C3 to CAM in response to environmental stresses such as salt treatment or water deficiency. To investigate fundamental photosynthetic patterns and the induction of pattern shifts (C3, CAM, C3-CAM etc.) as a result of environmental stresses, we measured the water content, diurnal changes in pH, net <TEX>$CO_2$</TEX> exchange, transpiration rate, total ionic contents, and osmolality of Kalancoe daigremontiana, Sedum kamschaticum and Sedum sarmentosum which belong to Crassulaceae known as representative CAM plant, after 10 days of drought treatment. S. kamschaticum and S. sarmentosum did not show a significant difference in diurnal pH variation in the treatment and control conditions. However, the pH of drought-treated Kalancoe was low at night and high in the daytime, with a pH value between 4 and 5. Typical CAM plants display a net <TEX>$CO_2$</TEX> exchange that increases at night and decreases in the daytime. Kalancoe displayed the predicted pattern. However, S. kamschaticum and S. sarmentosum showed a photosynthetic pattern more typical of C3 plants, and did not show changes in photosynthetic pattern under drought stress. Kalancoe also showed a transpiration rate typical for CAM pho-tosynthesis, whereas the transpiration rates of S. kamschaticum and S. sarmentosum were in the typical range for C3 photosynthesis. Kalancoe had high total ionic contents during the night, which decreased somewhat during the daytime, whereas S. kamschaticum and S. sarmentosum displayed the opposite pattern. This result is similar to the diurnal patterns of changes in pH in the three plant species, which suggests a relationship between pH and ionic contents. S. sarmentosum showed lower osmolality under drought stress than in the control condition, whereas the osmolality of Kalancoe and S. kamschaticum did not differ between conditions. S. sarmentosum may have maintained internal water content by lowering its osmolality and raising its total ionic contents. In conclusion, Kalancoe displayed the characteristic responses of a typical CAM plant, whereas S. kamschaticum and S. sarmentosum displayed aspects of the C3 photosynthetic pattern under drought conditions. These results suggest that S. kamschaticum and S. sarmentosum (Crassulacea) in Korea overcome drought stress by increasing solute and ionic contents internally rather than changing their photosynthetic pattern from C3 to CAM under drought stress.