scholarly journals Capillary rise and saliferous groundwater evaporation: effects of various solutes and concentrations

2019 ◽  
Vol 50 (2) ◽  
pp. 517-525 ◽  
Author(s):  
Xuguang Xing ◽  
Xianwen Li ◽  
Xiaoyi Ma
Keyword(s):  
Pore Structure ◽  
Conversion Coefficient ◽  
Dominant Role ◽  
Capillary Rise ◽  
Control Treatment ◽  
Capillary Water ◽  
Fresh Groundwater ◽  
Capillary Action ◽  
Short Period ◽  
Groundwater Evaporation

Abstract Capillary rise is capable of demonstrating the mechanism involved in groundwater evaporation, where the evaporation from saliferous groundwater could be quantized in accordance with fresh groundwater. The two types of experiments included 12 treatments with four solutes (KCl, NaCl, CaCl2, and MgCl2) that were dissolved in groundwater at three concentrations (5, 30, and 100 g/L), and one control treatment without the salt solutions. The results demonstrated that the capillary action played a dominant role only within a very short period of time at the beginning of evaporation (i.e. within 2 min). The total dissolved solids (TDS) of the groundwater that was dissolved with KCl or NaCl affected the capillary water gravity more than soil pore structure. The TDS of the groundwater that was dissolved with CaCl2 or MgCl2 affected both the capillary water gravity and the soil pore structure. During the groundwater evaporation process, the evaporation conversion coefficient CTDS (>1.0) had the potential to calculate the saliferous-groundwater evaporation in accordance with the fresh-groundwater evaporation. The CTDS values were the largest for the groundwater that was dissolved with KCl/NaCl and CaCl2/MgCl2 at 5 and 30 g/L, where it reached average values of 1.3530–1.3735 and 1.3257–1.3589.

scholarly journals Calculation of the Height of Capillary Rise of Water in Soils

2020 ◽  
Vol 8 (6) ◽  
pp. 4832-4835
Keyword(s):  
Water Saturation ◽  
Underground Structure ◽  
Capillary Rise ◽  
Soil Layer ◽  
Underground Water ◽  
Wall Material ◽  
Capillary Water ◽  
Temporary Streams ◽  
Filter Water ◽  
Soil Pores

Rain and melt water will form temporary accumulations of surface water on the surface. When they seep into the ground, temporary streams of leaky filter water are formed. If a limited section of water-resistant soil layer or the roof of an underground structure is encountered in the path of these waters, a temporary aquifer-the upper layer of ground water-may form above them. In temporary and permanent aquifers, the soil pores are completely filled with gravitational water, the degree of water saturation is equal to one, and there is pressure under the surface of underground water. Above this surface is a zone of capillary moisture, while the level of capillary rise is determined by the granulometric composition of the soil and ranges from tens of centimeters in sand to several meters in dusty and clay soils. Capillary water rises in the ground on free canals formed by mutually communicating pores, or is kept in them in limbo.The lifting of the liquid in the capillary continues until the gravity acting on the column of the liquid in the capillary becomes equal to the resulting force. Capillary water penetrates from the ground into the walls and rises to a height of up to 2 meters. The normal moisture content of the brick walls is 0.02...0,03, and in the case of unprotected contact with moist soil is increased to 0.15...0.25. On the inside of the walls there is a damp, mildew. Evaporating water increases humidity in the room, and the salts released when it evaporates from salt solutions lead to peeling paint, destruction of plaster and wall material.

Siliceous-sulphate rock coatings at Zhenzhu Spring, Tengchong, China: the integrated product of acid-fog deposition, spring water capillary action, and dissolution

2019 ◽  
Vol 157 (2) ◽  
pp. 201-212
Author(s):  
Huaguo Wen ◽  
Wenli Xu ◽  
Yi Li ◽  
Yaxian You ◽  
Xiaotong Luo
Keyword(s):  
Amorphous Silica ◽  
Hot Spring ◽  
Capillary Rise ◽  
Volcanic Field ◽  
Spring Water ◽  
Wet Season ◽  
Acid Fog ◽  
Capillary Action ◽  
Fog Deposition ◽  
Rock Coatings

AbstractSiliceous-sulphate rock coatings were observed at Zhenzhu Spring, an acid sulphate hot spring in the Tengchong volcanic field, China. These rock coatings are mainly formed of gypsum and amorphous silica. Some alum-(K), voltaite, α-quartz and muscovite were also found. Four different laminae are developed in the rock coatings: gypsum layer, tight siliceous layer, tabular siliceous layer and siliceous debris layer. The gypsum layer is located at the top of the rock coatings, while other siliceous layers appear below the gypsum layer. Geochemical modelling of the fluids was performed to identify the mechanisms responsible for the formation of gypsum and amorphous silica. The results indicated that the occurrence of gypsum is related to the acid-fog deposition and amorphous silica mainly originates from spring water. Fog deposition provided the rock coatings with abundant SO42− and Ca, and the subsequent complete evaporation of the condensed fluids produced gypsum. Seasonal climate change (especially variation in rainfall) determines the fluctuations of capillary action and dissolution. Rainfall events in the wet season led to periods of non-precipitating gypsum and promoted the capillary rise of the spring water. Slightly diluted capillary water (a small amount of rainwater) covered the rock coatings, formed a tight siliceous layer on the rock-coating surface and/or filled the pores among the gypsum crystals forming many tabular siliceous aggregates. Heavy rainfall (high dilution), however, resulted in non-precipitating amorphous silica and accelerated the gypsum dissolution, leaving tabular pores around tabular siliceous aggregates and forming a tabular siliceous layer.

scholarly journals The influence of ground slab permeability on wall moisture in a historic buildingThe influence of ground slab permeability on wall moisture in a historic buildingThe influence of ground slab permeability on wall moisture in a historic buildingThe influence of ground slab permeability on wall moisture in a historic building

2021 ◽  
Author(s):  
Kevin Briggs ◽  
Richard Ball ◽  
Iain McCaig
Keyword(s):  
Moisture Content ◽  
Capillary Rise ◽  
Building Envelope ◽  
Common Belief ◽  
Atmospheric Moisture ◽  
Limited Evidence ◽  
Increase Moisture Content ◽  
Capillary Action ◽  
Historic Building ◽  
Atmospheric Moisture Content

When impermeable ground bearing slabs are installed in old buildings without a damp-proof course, it is a common belief of practitioners within the conservation industry that ground moisture will be ‘driven’ up adjacent walls by capillary action. However, there is limited evidence to test this hypothesis. The accumulation of moisture in walls can promote the decay of the wall materials, decrease the thermal performance of the building envelope and adversely affect the comfort and health of occupants. An experiment was used to determine if the installation of a vapour-proof barrier above a stone flag floor in a historic building would increase moisture content levels in an adjacent stone rubble wall. This was achieved by undertaking measurements of wall, soil and atmospheric moisture content over a three-year period. Measurements taken using timber dowels showed that the moisture content within the wall did not vary in response to wall evaporation rates and did not increase following the installation of a vapour-proof barrier above the floor. This indicates that the moisture levels in the rubble wall were not driven by capillary rise.

scholarly journals A general form of capillary rise equation in micro-grooves

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Gholamreza Bamorovat Abadi ◽  
Majid Bahrami
Keyword(s):  
Drug Delivery ◽  
Contact Angle ◽  
Capillary Rise ◽  
Heat Pipes ◽  
Relative Difference ◽  
Groove Surface ◽  
Capillary Action ◽  
Two Parameters ◽  
Solid Liquid Interface ◽  
Sorption Systems

AbstractMicro-grooves are a crucial feature in many applications, such as microelectro-mechanical systems, drug delivery, heat pipes, sorption systems, and microfluidic devices. Micro-grooves utilize capillary action to deliver a liquid, with no need for an extra pumping device, which makes them unique and desirable for numerous systems. Although the capillary action is well studied, all the available equations for the capillary rise are case-specific and depend on the geometry of the groove, surface properties, and the transport liquid. In this study, a unified non-dimensional model for capillary rise is proposed that can accurately predict the capillary rise for any given groove geometry and condition and only depends on two parameters: contact angle and characteristic length scale, defined as the ratio of the liquid–vapor to the solid–liquid interface. The proposed model is compared against data from the literature and can capture the experimental results with less than 10% relative difference. The effect of the grooves’ height, width, and contact angle is investigated and reported. This study can be used for a unified approach in designing heat pipes, capillary-assisted evaporators for sorption systems, drug delivery micro-fluidic devices, etc.

scholarly journals Capillary Water Absorption and Micro Pore Connectivity of Concrete with Fractal Analysis

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 892
Author(s):  
Xiangqun Ding ◽  
Xinyu Liang ◽  
Yichao Zhang ◽  
Yanfeng Fang ◽  
Jinghai Zhou ◽  
...  
Keyword(s):  
Pore Structure ◽  
Water Absorption ◽  
Fractal Theory ◽  
Mineral Admixtures ◽  
Capillary Water ◽  
Capillary Water Absorption ◽  
Connectivity Probability ◽  
Fractal Characteristics ◽  
Different Diameters ◽  
The Relationship

This study focuses on the relationship between the complexity of pore structure and capillary water absorption of concrete, as well as the connection behavior of concrete in specific directions. In this paper, the water absorption of concrete with different binders was tested during the curing process, and the pore structure of concrete was investigated by mercury intrusion porosimetry (MIP). The results show that the water absorption of concrete with mineral admixtures is lower, mainly due to the existence of reasonable pore structure. The effect of slag on concrete modification is more remarkable comparing with fly ash. In addition, the analysis shows that the pore with different diameters has different fractal characteristics. The connectivity probability and water absorption of unidirectional chaotic pore are linearly correlated with the pore diameter of 50–550 nm, and the correlation coefficient reaches a very significant level, and detailed analysis was undertaken to interpret these results based on fractal theory.

The influence of dynamic environmental conditions on capillary water uptake of building materials

2018 ◽  
Vol 42 (4) ◽  
pp. 506-526 ◽  
Author(s):  
Nikos Karagiannis ◽  
Maria Karoglou ◽  
Asterios Bakolas ◽  
Magdalini Krokida ◽  
Antonia Moropoulou
Keyword(s):  
Water Uptake ◽  
Environmental Conditions ◽  
Building Materials ◽  
Capillary Rise ◽  
Assessment Tools ◽  
Real Case ◽  
Capillary Absorption ◽  
Capillary Water ◽  
Proposed Model ◽  
Capillary Water Uptake

Water capillary absorption is one of the main water uptake mechanisms in building materials, affecting their overall durability. Thus, the investigation of their capillary rise kinetics can be very useful as regards understanding buildings behavior, contributing to the increase of their durability and their service life. For this reason, a first-order mathematical model was used describing the capillary water uptake under dynamic environmental conditions (different air velocity, air temperature, and relative air humidity) for various natural and artificial building materials. This model successfully fits the experimental data. From the results, it was found that both building materials’ intrinsic characteristics and environmental conditions influence the capillary rise kinetics. In order to assess the validity of the proposed model, a comparison with a similar model was performed. The fitting of the utilized model was more accurate because of the incorporation of the environmental parameters into it. Finally, the proposed model was utilized in order to predict the capillary water uptake under hypothetical extreme weather real-case scenarios. It was found that the proposed model can successfully predict the capillary water uptake under different real-case environmental conditions. The applicability of this semi-empirical model, using parameters with physical meaning, could make it suitable for use in building simulators. This model can contribute to risk assessment tools, dealing with various challenges related to climate change and its effect upon built environment.

scholarly journals Characterization of Microscopic Pore Structures of Rock Salt through Mercury Injection and Nitrogen Absorption Tests

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Jianwen Chen ◽  
Erbing Li ◽  
Jin Luo
Keyword(s):  
Pore Structure ◽  
Pore Size ◽  
Rock Salt ◽  
Dominant Role ◽  
Injection Rate ◽  
Pore Channel ◽  
Nitrogen Absorption ◽  
Pore Throat ◽  
Throat Radius ◽  
Mercury Injection

Microscopic pore structure of rock salt plays a dominant role in its permeability. In this paper, microscopic pore structure of a set of rock salt samples collected from Yunying salt mine of Hubei province in China is investigated by high pressure mercury injection, rate-controlled mercury penetration, and nitrogen absorption tests. The pore size distribution is further evaluated based on fractal analysis. The results show that pore size of rock salt varies from 0.01 to 300 μm with major concentration of pore size smaller than 1.00 μm. The pore’s radiuses are mainly distributed within a range between 15 and 50 nm. The research further reveals that the pore channel size of rock salt is randomly distributed, but the distribution of pore throat radius fits very well with fractal law. By analysis of permeability, it is found that the maximum and medium radius of the pore throat have significant impacts on permeability. Porosity is not apparently related to the permeability of rock salt. The higher the fractal dimension is, the higher the impacts on permeability of the small throat are detected and the lower the influence on permeability of the big throat is exhibited. It indicates that the small throat determines majorly the permeability of rock salt. The findings obtained from this study provide an insight into understanding the characteristics of microscopic pore structure of rock salt.

Quantitative characterization and characteristic analysis of pore structure of shale-gas reservoir in the Sichuan Basin, China

2019 ◽  
Vol 7 (4) ◽  
pp. SJ23-SJ32 ◽  
Author(s):  
Huaimin Dong ◽  
Jianmeng Sun ◽  
Jinjiang Zhu ◽  
Zhenzhou Lin ◽  
Likai Cui ◽  
...  
Keyword(s):  
Pore Structure ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Conversion Coefficient ◽  
Gas Reservoir ◽  
Quantitative Characterization ◽  
Hybrid Detection ◽  
The Sichuan Basin ◽  
Aperture Distribution

Quantitative characterization of pore structure in shale can provide basic parameters for evaluation of the shale-gas reservoir quality. However, it is difficult to use conventional methods to accurately and comprehensively characterize the pore structure parameters. We take shale samples from the Longmaxi Formation in the Sichuan Basin as the study object, and we use the high-pressure mercury intrusion, nitrogen adsorption, and carbon dioxide adsorption methods to characterize the whole aperture distribution. We found that the pore size in shale is positively related to the transverse relaxation time ([Formula: see text] value) and there exists a conversion coefficient. We have developed a new method combining nuclear magnetic resonance (NMR) with hybrid detection methods for testing the pore size distribution, and we optimized the conversion coefficient between pore size obtained by a hybrid detection method and the [Formula: see text] value. NMR can then characterize the pore size distribution by conversion coefficient. This method can effectively make up for the deficiency of conventional methods for pore size distribution characterization by a single method. Our results indicate that the macropore, mesopore, and micropore in shale are very developed, and the pore shapes are ink bottle and slit-like. Shale pores mainly consist of mesopore and micropore, contributing to approximately 74.33% of pore volume, whereas micropore contributes approximately 70.18% of specific surface area (SSA). Therefore, the macropore has a limited effect on the pore volume and SSA. In addition, the establishment of whole aperture distribution characterization by the new method can more comprehensively reflect the actual pore distribution in shale.

scholarly journals CAN SMOS SOIL MOISTURE DRY-DOWNS BE USEFUL TO DETECT FLOOD CONDITIONS OVER THE ARGENTINEAN PAMPAS PLAINS?

2020 ◽  
Vol XLII-3/W12-2020 ◽  
pp. 279-283
Author(s):  
L. Cappelletti ◽  
A. Sörensson ◽  
R. Ruscica ◽  
M. M. Salvia ◽  
E. Jobbágy ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Time Scales ◽  
Capillary Rise ◽  
Precipitation Anomaly ◽  
Water Dynamics ◽  
Atmospheric Conditions ◽  
Short Period ◽  
Dry Down ◽  
Spatio Temporal ◽  
Vegetation Water

Abstract. The process of soil drying following a single rainfall input offers an integrated perspective on soil-vegetation water dynamics in responses to atmospheric conditions during periods without rainfall. In this work, the soil moisture dry-down time scale events (τ) was calculated using surface soil moisture data from the SMOS mission, with the objective to explore if the spatio-temporal variability of τ could be used as a proxy for regional flooding and waterlogging characterization. Our working hypothesis is that soil moisture dries up more slowly under flooded conditions as a result of slower surface water elimination by infiltration and capillary rise of water from the saturated zone close to the surface. A clear difference precipitation-moisture coupling was detected between two regions with different flooding dynamics. In a region where flooding is triggered by precipitation excesses on weekly-to-monthly time scales and where the coupling between precipitation and evapotranspiration is strong, a positive correlation between dry-down and 6-month accumulated precipitation anomaly was found for all seasons except winter. By contrast, in the other region where flooding is largely de-coupled from precipitation and evapotranspiration, but rather coupled to ground water table dynamics on time scales from several months to years, no significant correlations were found. These results are based on a short period of data: March 2010 – November 2014.

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