Photospectroscopically observed pore-space correlations of a wetting fluid during the drying process in nanoporous Vycor glass

2015 ◽  
Vol 32 (4) ◽  
pp. 533 ◽  
Author(s):  
Shigeo Ogawa ◽  
Jiro Nakamura
Keyword(s):  
Pore Space ◽  
Drying Process ◽  
Vycor Glass ◽  
Wetting Fluid

Elastic wave velocities during evaporative drying

Geophysics ◽  
1998 ◽  
Vol 63 (1) ◽  
pp. 171-183 ◽  
Author(s):  
David Goertz ◽  
Rosemary Knight
Keyword(s):  
Elastic Wave ◽  
Pore Space ◽  
Fluid Distribution ◽  
Drying Process ◽  
Shear Moduli ◽  
Velocity Saturation ◽  
Wave Velocities ◽  
Three Samples ◽  
Rate Period ◽  
Drying Rates

Laboratory measurements of drying rates and elastic wave velocities are made on limestone, dolomite, and sandstone samples during evaporative drying. The drying rate data are very similar in form. There is a constant rate period at higher saturations and a falling rate period below saturation levels of approximately 0.2. The falling rate period marks the transition in the sample from hydraulically connected to disconnected water. There is a strong link between elastic wave velocities and the drying process because different pore geometries drain at different stages in drying. The drainage of these different geometries results in specific changes in the moduli and velocities. Simple models of the pore geometries and the drying process are used to model the velocity data. The velocity‐saturation relationship for each of the three samples is very different in form because of differences in pore‐space microgeometry. Of particular interest is the velocity response during the falling rate period of drying. In the limestone and the sandstone, there is a significant decrease in bulk and shear moduli and elastic wave velocities because of the drainage of crack‐like pores and grain contacts. In contrast, the absence of these pore geometries in the dolomite results in essentially no changes in the moduli at low saturations. An understanding of the drying process and resulting pore‐scale fluid distribution provides useful insights into the observed form of the velocity‐saturation relationship.

Cryo-SEM of liquid-bearing rock

1988 ◽  
Vol 46 ◽  
pp. 104-105 ◽  
Author(s):  
E. Sutanto
Keyword(s):  
Pore Space ◽  
Contact Angles ◽  
Solid Surfaces ◽  
Fluid Distribution ◽  
Pore Geometry ◽  
Flow Through Porous Media ◽  
Flow Through ◽  
Grain Surface ◽  
Wetting Fluid ◽  
Local Nature

Scanning electron microscopy has been used to examine microstructure of dry soils, sedimentary rocks and other porous materials for three decades. There are many studies of sand grain surface texture, pore morphology, and clay swelling. However, pore geometry and surface topography are only part of the story of how two or more fluids flow through porous media, whether they be unconsolidated or consolidated. The other part is how the fluids distribute in the pore space. Fluid distribution in pore space is largely governed by relative wettability of pore walls. Wetting fluid tends to reside on walls as a thin film and to occupy small pores totally, whereas nonwetting fluid tends to occupy the center of larger pores. Which fluid is more strongly wetting depends on the local nature of the wall. Contact angles indicate wettability of planar, homogeneous solid surfaces, but roughness and compositional heterogeneity, which seem to be common in sedimentary rock, complicate matters.

scholarly journals X-ray microtomography analysis of soil structure deformation caused by centrifugation

2015 ◽  
Vol 7 (4) ◽  
pp. 2807-2831 ◽  
Author(s):  
S. Schlüter ◽  
F. Leuther ◽  
S. Vogler ◽  
H.-J. Vogel
Keyword(s):  
Soil Compaction ◽  
Soil Structure ◽  
Pore Space ◽  
Fast Method ◽  
Drying Process ◽  
Soil Water Retention ◽  
X Ray ◽  
High Rotation Speed ◽  
Swelling Clay Minerals ◽  
Soil Constituents

Abstract. Centrifugation provides a fast method to measure soil water retention curves over a wide moisture range. However, deformation of soil structure may occur at high rotation speed in the centrifuge. These changes in soil structure were analyzed with X-ray microtomography. A detailed analysis of the pore space reveals an interplay between shrinkage due to drying and soil compaction due to compression. While volume changes due to swelling clay minerals are immanent to any drying process, the compaction of soil is a specific drawback of the centrifugation method. A new protocol for digital volume correlation was developed to analyze the spatial heterogeneity of deformation. The displacement of soil constituents is highest in the top part of the sample and exhibits high lateral variability explained by the spatial distribution of macropores in the sample. Centrifugation should therefore only be applied after the completion all other hydraulic or thermal experiments, or any other analysis that depends on the integrity of soil structure.

scholarly journals Immiscible capillary flows in non-uniform channels

2021 ◽  
Vol 925 ◽  
Author(s):  
Patrick K. Mortimer ◽  
Andrew W. Woods
Keyword(s):  
Pore Space ◽  
Classical Model ◽  
Early Time ◽  
Bond Number ◽  
Late Time ◽  
Exchange Flow ◽  
One Dimensional ◽  
Capillary Flows ◽  
Intermediate Time ◽  
Wetting Fluid

We consider the release of preferentially wetting fluid in a laterally extensive V-shaped channel initially filled with a second fluid, presenting solutions for the initial exchange flow and the late time spreading of the wetting fluid along the narrow part of the channel. We also show that, if there is a buoyancy force acting in the cross-channel direction, the early time exchange flow depends on the Bond number, and the intermediate time slumping flow may initially be dominated by buoyancy, but at long times becomes controlled by capillarity. Where there is an along-channel component of gravity we show that the flow spreads out downslope, with capillarity controlling the structure of the nose. We then consider the case where the channel is connected to a reservoir of wetting fluid at constant pressure. We show that, depending on this pressure, either a zero flux exchange flow develops, or a net inflow through the whole width of the channel develops, as in the classical Washburn, Lucas, Bell and Cameron capillary imbibition flow. We show these flows are analogous to the classical model for one-dimensional capillary driven flows in porous media, with the current width in the channel corresponding to the saturation in the pore space.

Spontaneous Imbibition of Liquids into Nanopores

2005 ◽  
Vol 899 ◽  
Author(s):  
Patrick Huber ◽  
Klaus Knorr ◽  
Andriy V. Kityk
Keyword(s):  
Liquid Crystal ◽  
Pore Radius ◽  
Pore Space ◽  
Capillary Rise ◽  
Spontaneous Imbibition ◽  
Bulk Fluid ◽  
Vycor Glass ◽  
Mass Uptake ◽  
Good Agreement ◽  
Fluid Parameters

AbstractWe present measurements on the spontaneous imbibition of water, a linear hydrocarbon (n-C16H34) and a liquid crystal (8OCB) into the pore space of monolithic, nanoporous Vycor glass (mean pore radius 5nm). Measurements of the mass uptake as a function of time, m(t), are in good agreement with the Lucas-Washburn - prediction typical of imbibition of liquids into porous hosts. The relative capillary rise velocities scale as expected from the bulk fluid parameters.

Video real-time imaging of artificial membranes during freeze-drying by cryo-electron microscopy

1988 ◽  
Vol 46 ◽  
pp. 16-17
Author(s):  
Alan S. Rudolph ◽  
Ronald R. Price
Keyword(s):  
Real Time ◽  
Self Assembly ◽  
Freeze Drying ◽  
Video Capture ◽  
Drying Process ◽  
Artificial Membranes ◽  
The Past ◽  
Cryo Electron Microscopy ◽  
Spherical Structures ◽  
Capture Techniques

We have employed cryoelectron microscopy to visualize events that occur during the freeze-drying of artificial membranes by employing real time video capture techniques. Artificial membranes or liposomes which are spherical structures within internal aqueous space are stabilized by water which provides the driving force for spontaneous self-assembly of these structures. Previous assays of damage to these structures which are induced by freeze drying reveal that the two principal deleterious events that occur are 1) fusion of liposomes and 2) leakage of contents trapped within the liposome [1]. In the past the only way to access these events was to examine the liposomes following the dehydration event. This technique allows the event to be monitored in real time as the liposomes destabilize and as water is sublimed at cryo temperatures in the vacuum of the microscope. The method by which liposomes are compromised by freeze-drying are largely unknown. This technique has shown that cryo-protectants such as glycerol and carbohydrates are able to maintain liposomal structure throughout the drying process.

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