Mean field theories of ion distributions, such as the Gouy-Chapman theory that describes distribution near a charged planar surface, ignore molecular-scale structure in liquid solution. The predictions vary substantially from our x-ray reflectivity measurements interface between two electrolyte solutions. Molecular dynamics simulations, which include structure, were used to calculate potential mean force on single ion. We this generalized Poisson-Boltzmann equation predict full...

This study presents the classification and prediction of severity for brittle rock failure, focusing on failure behaviors excessive determination based damage depth. The research utilizes extensive field survey data from Shuangjiangkou Hydropower Station previous findings. Based surveys studies, four types with different mechanisms are classified, then a method is proposed. incorporates two variables, i.e. Kv (modified mass integrity coefficient) GSI (geological strength index). applied to...

Selective extraction of metal ions from a complex aqueous mixture into an organic phase is used to separate toxic or radioactive metals polluted environments and nuclear waste, as well produce industrially relevant metals, such rare earth ions. Selectivity arises the choice extractant amphiphile, dissolved in phase, which interacts preferentially with target ion. The extractant-mediated process ion transport takes place at aqueous–organic interface; nevertheless, little known about molecular...

Abstract Natural faults are often heterogeneous with spatially variable cohesion caused by healing processes. Using rock bridges as laboratory analogs, we investigate how cohesion‐healed patches rupture at different shear rates. We performed direct experiments on granite rates from 1 μm/s to 10 mm/s (low subseismic rates), and quantitatively characterized the failure surface morphology integrating laser scanning ArcGIS. The results show a notable dependence of both mechanical morphological...

We present X-ray reflectivity and interfacial tension measurements of the electrified liquid/liquid interface between two immiscible electrolyte solutions for purpose understanding dependence ion distributions on applied electric potential difference across interface. The aqueous phase contains alkali-metal chlorides, including LiCl, NaCl, RbCl, or CsCl, organic is a 1,2-dichloroethane solution bis(triphenylphosphor anylidene) ammonium tetrakis(pentafluorophenyl)borate (BTPPATPFB). Selected...

Discontinuities are often considered as important factors responsible for the instability caused by shear failure in engineering rock mass, and energy-driven is root cause of failure. However, few studies focus on energy evolution during process using a three-dimensional (3D) numerical model. In this study, series laboratory direct tests rock-like samples numerically simulated bonded particle models (BPMs) with multiple combinations discontinuous flow code (PFC3D), which location size...

Entrapment of biomolecules in silica-derived sol−gels has grown into a vibrant area research since it was originally demonstrated. However, accessing the consequences entrapment on and gel structure remains major challenge characterizing these biohybrid materials. We present first demonstration that is possible with small-angle neutron scattering (SANS) to study conformation dilute proteins are entrapped transparent dense sol−gels. Using deuterium-labeled green fluorescent protein (GFP) SANS...

The interface between water and mixed surfactant solutions of CH3(CH2)19OH CF3(CF2)7(CH2)2OH in hexane was studied with interfacial tension X-ray reflectivity measurements. Measurements the as a function temperature for range total bulk concentrations three different values molal ratio fluorinated to concentration (0.25, 0.28, 0.5) determined that can be monolayer phases. excess entropy these phases suggests two are condensed single monolayers CF3(CF2)7(CH2)2OH. By studying four compositions...

We demonstrate the use of X-ray reflectivity to probe electron density profile normal interface between two polar liquids. Measurements interfacial width at neat nitrobenzene/water and water/2-heptanone interfaces are presented. These widths consistent with predictions from capillary wave theory that describe thermal fluctuations determined by tension bending rigidity interface. Variation temperature water/nitrobenzene 25 degrees C 55 indicates role decreases increasing temperature....

X-ray reflectivity studies demonstrate the condensation of a monovalent ion at electrified interface between electrolyte solutions water and 1,2-dichloroethane. Predictions distributions by standard Poisson–Boltzmann (Gouy–Chapman) theory are inconsistent with these data higher applied interfacial electric potentials. Calculations from equation that incorporates nonmonotonic ion-specific potential mean force in good agreement data.

Complex interactions that determine ionic ordering in the bulk of electrolyte solutions are modified by surface-region inhomogeneities. We present results from an investigation surface-ionic profiles provide insights into underlying physical chemistry this region. X-ray reflectivity measurements liquid surfaces aqueous ErCl3 reveal unprecedented detail a nonmonotonic electron density profile, which is interpreted terms surface distribution cations (Er3+) and their relationship to bulk. The...

The shear strength of the rock discontinuities under different rates is great importance to evaluate stability mass engineering, which remarkably influenced by size effects induced both length and undulated amplitude discontinuities. An advanced criterion taking into account rate simultaneously was proposed. There an advantage dimension unity in terms new comparison previous related empirical equations. Additionally, it can be degraded International Society for Rock Mechanics...

Understanding the shear mechanical properties of shale reservoirs is great significance in study formation stability around horizontal wells and propagation evolution fractures for fracturing. However, existing direct test results are limited due to small sample sizes low rates. Based on previous experimental research results, anisotropic reservoir tests with different conditions were explored this study. It was found that mode, strain rate, normal stress have a significant impact...

X-ray fluorescence near total reflection (XFNTR) is measured from the liquid/liquid interface between dodecane and an ErCl3 aqueous solution by monitoring L shell Er emission lines. A custom sample cell used to minimize absorption of x-rays that pass through on their way detector. The Er3+ concentration related intensity a scale factor extracted fitting incident-angle dependent Lα line intensities for different bulk concentrations. As application, we present use XFNTR monitor growth...

Grazing-incidence (GI) X-ray absorption spectroscopy (XAS) under conditions of total external reflection is used to explore the coordination environment trivalent erbium ion, Er(3+), at an electrolyte-vapor interface. A parallel study bulk aqueous electrolyte (1 M ErCl3 in HCl pH = 1.54) shows that Er(3+) ions have a simple hydration shell with average Er-OH2 bond distance 2.33(1) Å, consistent previous descriptions aquated cation, [Er(OH2)8](3+). No other correlations are observed EXAFS...

Abstract X‐ray reflectivity studies of surfactants at the water‐oil interface yield structural information with sub‐nanometer resolution. In this presentation, we reviewed recent measurements between water and a hexane solution hydrocarbon alkanol CH3(CH2)19OH fluorocarbon CF3(CF2)7(CH2)2OH. The mixed system exhibits three monolayer phases, two which are similar to single surfactant phases. A transition from liquid solid occurs increasing temperature. This unusual phase qualitative features...