Hydro-Mechanical-Chemical Coupled Processes in Fractured Porous Media: Pressure Solution Creep

Pressure solution creep is a fundamental deformation mechanism in the upper crust. Overburden pressure that acts upon layers of sediment leaves grains densely packed. Nonhydrostatic stress distributed over the contacts between grains brings an enhancement effect on surface dissolution. As surface retreat over the contacts and hence grain repacking squeeze out pore water in the voids, the layers of sediment are deformed to become denser and denser. This work aims to identify what process slows down pressure solution creep over time. For this purpose, a new mechanistic model of pressure solution creep is developed, derived from the reaction rate law for nonhydrostatic dissolution kinetics under the hypothesis of a closed system. The present mechanistic model shows that (1) the creep rate goes down as a combined consequence of stress transfer across expanding contacts and concentration build-up in the interlayer of absorbed water; and (2) solute migration process acts as the primary rate-limiting process of pressure solution creep in the long run. This work then focuses on hydraulic evolution of channelling flow through a single deformable fracture which is simultaneously subjected to pressure solution creep. The developed 1-D reactive transport model is allowed to capture the strong interaction between channelling flow and pressure solution creep under crustal conditions. This numerical investigation provides a justified interpretation for the unusual experimental observation that fracture permeability reduction does not necessarily cause concentration enrichment. Temperature elevation contributes to accelerating the progression of pressure solution creep

Interplay between moment-dependent and field-driven unidirectional magnetoresistance in CoFeB/InSb/CdTe heterostructures

Magnetoresistance effects are crucial for understanding the charge/spin transport as well as propelling the advancement of spintronic applications. Here we report the coexistence of magnetic moment-dependent (MD) and magnetic field-driven (FD) unidirectional magnetoresistance (UMR) effects in CoFeB/InSb/CdTe heterostructures. The strong spin-orbital coupling of InSb and the matched impedance at the CoFeB/InSb interface warrant a distinct MD-UMR effect at room temperature, while the interaction between the in-plane magnetic field and the Rashba effect at the InSb/CdTe interface induces the marked FD-UMR signal that dominates the high-field region. Moreover, owning to the different spin transport mechanisms, these two types of nonreciprocal charge transport show opposite polarities with respect to the magnetic field direction, which further enable an effective phase modulation of the angular-dependent magnetoresistance. Besides, the demonstrations of both the tunable UMR response and two-terminal spin-orbit torque-driven magnetization switching validate our CoFeB/InSb/CdTe system as a suitable integrated building block for multifunctional spintronic device design

Transcriptional Homeostasis of a Mangrove Species, Ceriops tagal, in Saline Environments, as Revealed by Microarray Analysis

<div><h3>Background</h3><p>Differential responses to the environmental stresses at the level of transcription play a critical role in adaptation. Mangrove species compose a dominant community in intertidal zones and form dense forests at the sea-land interface, and although the anatomical and physiological features associated with their salt-tolerant lifestyles have been well characterized, little is known about the impact of transcriptional phenotypes on their adaptation to these saline environments.</p> <h3>Methodology and Principal findings</h3><p>We report the time-course transcript profiles in the roots of a true mangrove species, <em>Ceriops tagal</em>, as revealed by a series of microarray experiments. The expression of a total of 432 transcripts changed significantly in the roots of <em>C. tagal</em> under salt shock, of which 83 had a more than 2-fold change and were further assembled into 59 unigenes. Global transcription was stable at the early stage of salt stress and then was gradually dysregulated with the increased duration of the stress. Importantly, a pair-wise comparison of predicted homologous gene pairs revealed that the transcriptional regulations of most of the differentially expressed genes were highly divergent in <em>C. tagal</em> from that in salt-sensitive species, <em>Arabidopsis thaliana</em>.</p> <h3>Conclusions/Significance</h3><p>This work suggests that transcriptional homeostasis and specific transcriptional regulation are major events in the roots of <em>C. tagal</em> when subjected to salt shock, which could contribute to the establishment of adaptation to saline environments and, thus, facilitate the salt-tolerant lifestyle of this mangrove species. Furthermore, the candidate genes underlying the adaptation were identified through comparative analyses. This study provides a foundation for dissecting the genetic basis of the adaptation of mangroves to intertidal environments.</p> </div

Hydro-Mechanical-Chemical Coupled Processes in Fractured Porous Media: Pressure Solution Creep

Pressure solution creep is a fundamental deformation mechanism in the upper crust. Overburden pressure that acts upon layers of sediment leaves grains densely packed. Nonhydrostatic stress distributed over the contacts between grains brings an enhancement effect on surface dissolution. As surface retreat over the contacts and hence grain repacking squeeze out pore water in the voids, the layers of sediment are deformed to become denser and denser. This work aims to identify what process slows down pressure solution creep over time. For this purpose, a new mechanistic model of pressure solution creep is developed, derived from the reaction rate law for nonhydrostatic dissolution kinetics under the hypothesis of a closed system. The present mechanistic model shows that (1) the creep rate goes down as a combined consequence of stress transfer across expanding contacts and concentration build-up in the interlayer of absorbed water; and (2) solute migration process acts as the primary rate-limiting process of pressure solution creep in the long run. This work then focuses on hydraulic evolution of channelling flow through a single deformable fracture which is simultaneously subjected to pressure solution creep. The developed 1-D reactive transport model is allowed to capture the strong interaction between channelling flow and pressure solution creep under crustal conditions. This numerical investigation provides a justified interpretation for the unusual experimental observation that fracture permeability reduction does not necessarily cause concentration enrichment. Temperature elevation contributes to accelerating the progression of pressure solution creep

Hydro-Mechanical-Chemical Coupled Processes in Fractured Porous Media: Pressure Solution Creep

Pressure solution creep is a fundamental deformation mechanism in the upper crust. Overburden pressure that acts upon layers of sediment leaves grains densely packed. Nonhydrostatic stress distributed over the contacts between grains brings an enhancement effect on surface dissolution. As surface retreat over the contacts and hence grain repacking squeeze out pore water in the voids, the layers of sediment are deformed to become denser and denser. This work aims to identify what process slows down pressure solution creep over time. For this purpose, a new mechanistic model of pressure solution creep is developed, derived from the reaction rate law for nonhydrostatic dissolution kinetics under the hypothesis of a closed system. The present mechanistic model shows that (1) the creep rate goes down as a combined consequence of stress transfer across expanding contacts and concentration build-up in the interlayer of absorbed water; and (2) solute migration process acts as the primary rate-limiting process of pressure solution creep in the long run. This work then focuses on hydraulic evolution of channelling flow through a single deformable fracture which is simultaneously subjected to pressure solution creep. The developed 1-D reactive transport model is allowed to capture the strong interaction between channelling flow and pressure solution creep under crustal conditions. This numerical investigation provides a justified interpretation for the unusual experimental observation that fracture permeability reduction does not necessarily cause concentration enrichment. Temperature elevation contributes to accelerating the progression of pressure solution creep

1D_model_time_outflow_2.csv

For Figure 8(a):<br>Initial contact area ratio Rc0: 1.90%; <br>Initial mean mechanical aperture bm0: 9.1147 micro

1D_model_time_outflow_5.csv

For Figure 8(b):<br><br>Initial contact area ratio Rc0: 1.95%; <br>Initial mean mechanical aperture bm0: 10.1309 micro

Dataset of hydraulic aperture and effluent element concentrations over time

Numerical results presented in the article "Modelling of dissolution-induced permeability evolution of a granite fracture under crustal conditions". <br><br>File name: 1D_model_time_outflow_1.csv<br>Shown in Figure 6 and Figure 7<br>Initial contact area ratio R_c0: 1.95%; <br>Initial mean mechanical aperture b_m0: 9.12082 micro;<br><br>File name: 1D_model_time_outflow_2.csv<br>Shown in Figure 8(a)<br>Initial contact area ratio R_c0: 1.90%; <br>Initial mean mechanical aperture b_m0: 9.1147 micro;<br><br>File name: 1D_model_time_outflow_3.csv<br>Shown in Figure 8(a)<br>Initial contact area ratio R_c0: 2.0%; <br>Initial mean mechanical aperture b_m0: 9.1208 micro;<br><br>File name: 1D_model_time_outflow_4.csv<br>Shown in Figure 8(b)<br>Initial contact area ratio R_c0: 1.95%; <br>Initial mean mechanical aperture b_m0: 8.1047 micro;<br><br>File name: 1D_model_time_outflow_5.csv<br>Shown in Figure 8(b)<br>Initial contact area ratio R_c0: 1.95%; <br>Initial mean mechanical aperture b_m0: 10.1309 micro;<br