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The NaCl–H 2 O binary is a first approximation to fluids in the deep crust and upper mantle. Such fluids are fundamental to understanding geophysical properties, metal transport, and ore genesis within the Earth. Consequently, recent experimental studies have sought to determine the equation of state of the NaCl–H 2 O binary as a function of composition. However, experimental characterization is not straightforward at extreme conditions and there is so far little understanding of the molecular nature of associated fluids. Variations in the structure of water, ion solvation, and ion association affect properties such as ionic strength and electrical conductivity. These properties in turn influence geophysical signatures and metal solubilities at high pressure and temperature (P,T). We performed a series of NPT ab initio molecular dynamics simulations as a function of pressure (0.5–4.5 GPa), temperature (20–800 °C), and composition (1–14 m NaCl) to develop a molecular-level understanding of high P,T NaCl brines. Comparison of simulation results with experimental and theoretical densities provides a foundation for testing current levels of theory. The simulations have allowed us to determine the nature of ion solvation, ion association, and the effect of solutes on the solvent at high P,T. The PBE functional used here is known to over-structure water and overestimate the density of aqueous fluids at ambient conditions. This is due to an inadequate treatment of hydrogen bonding and dispersion. However, we find excellent agreement between theory and experimental densities at elevated P,T. Accordingly, we have extrapolated the existing equation of state to regions that have not been measured experimentally. From the O–O pair distribution functions, we interpret the improved agreement as resulting from the breakdown of hydrogen bonding at high P,T. At ambient conditions, the presence of Na and Cl has a strong effect on the structure of water. However, at high P,T, even 14 m NaCl has no effect on water structure. Nevertheless, Na and Cl are highly associated. We propose that NaCl brines at high P,T are best described as hydrous melts rather than as aqueous electrolytes. [ABSTRACT FROM AUTHOR]

Electrical conductivities of the clinopyroxene (Cpx)‐NaCl‐H2O system with various salinities (5, 10, 15, 20, 25 wt%) and fluid fractions (5, 10, 15, 20, 25 vol%) were measured at 1 GPa and 673–973 K. For comparison with electrical properties of the Cpx‐NaCl‐H2O system, the conductivities of dry Cpx, hydrous Cpx, and a Cpx‐H2O system were researched at the same temperature and pressure. The experimental results included (1) the electrical conductivities of all samples that were associated with Cpx and the temperatures conform to the Arrhenius relationship that is used to fit the activation enthalpy, which decreased with increasing salinity (mass fraction of NaCl in saline fluids) and fluid fraction (volume fraction of saline fluids in the Cpx‐NaCl‐H2O system); (2) at a fixed fluid fraction of 10 vol%, the conductivities of the Cpx‐NaCl‐H2O system increased slightly with an increase in salinity, and the gap between the conductivities of the systems with 5 and 25 wt% saline fluids was approximately 1 order of magnitude; (3) at a fixed salinity of 5 wt%, the conductivity of the Cpx‐NaCl‐H2O system with 25 vol% saline fluids was approximately 1.5 orders of magnitude higher than that of the system with 5 vol% saline fluids. Furthermore, it was proposed that the unusually high conductivities of southern Tibetan Plateau, Dabie Orogen, Grenville province and central New Zealand can be caused by clinopyroxene with interconnected saline fluids with corresponding salinities and fluid fractions. Key Points: Electrical properties of clinopyroxene‐NaCl‐H2O system with various salinities and fluid fractions were for the first time researchedSalinity and fluid fraction significantly influence the conductivities of clinopyroxene‐NaCl‐H2O system, but the temperature effect is weakSome high‐conductivity anomalies in the deep crust and subduction zone can be caused by the clinopyroxene‐NaCl‐H2O system [ABSTRACT FROM AUTHOR]

The process chain for Carbon Capture and Sequestration (CCS) includes tubing for injection of CO2 into saline aquifers. The compressed CO2 is likely to contain specific impurities; small concentrations of SO2and NO2 in combination with oxygen and humidity are most harmful. In addition, CO2 saturated brine is supposed to rise in the well when the injection process is interrupted. The material selection has to ensure that neither CO2 nor brine or a combination of both will leak out of the inner tubing. In this comprehensive paper the investigated materials range from low-alloy steels and 13% Cr steels up to high-alloy materials. Electrochemical tests as well as long term exposure tests were performed in CO2, in brine and combination of both; pressure was up to 100 bar, temperature up to 60 °C. Whereas the CO2 stream itself can be handled using low alloy steels, combinations of CO2 and brine require more resistant materials to control the strong tendency to pitting corrosion. The corrosion behavior of heat-treated steels depends on factors such as microstructure and carbon content. For different sections of the injection tube, appropriate materials should be used to guarantee safety and consider cost effectiveness. [ABSTRACT FROM AUTHOR]

• Three-dimensional magnetotelluric imaging of the Changbaishan-Tianchi volcano. • The crustal (10–16 km) high conductivity region beneath Tianchi may be a magma chamber. • Partial melting is required at the upper mantle ~50 km beneath Tianchi. • Crustal magma chamber could be supplied by the upper mantle partial melting. Changbaishan-Tianchi volcano is a potentially hazardous intraplate volcano, and has gained increasing concern because of its volcanic unrest between 2002 and 2006. However, the magma system beneath this volcano is not well understood yet. Electrical resistivity is highly sensitive to the presence of interconnected partial melt and/or saline fluid. A total of 41 magnetotelluric (MT) sites were occupied along a ~120 km profile crossing the Tianchi volcano. Both broadband and long period MT data were collected for each site. A crustal and uppermost mantle resistivity model was constructed by three-dimensional (3D) inversion of the quality off-diagonal impedance of MT data. Beneath the volcano, the model shows three spatial consistent high conductive zones at a depth of 3–5, 10–16 and 40–60 km, separately. Melt fraction of 6–8% is required to interpret the uppermost mantle high conductive anomaly, which might be caused by the decompression melting of upwelling asthenosphere. The middle crust high conductive zone is interpreted as a magma chamber with 7–30% melt, which could be supplied by the partial melting in the uppermost mantle. The porous saline zone with porosity of about 2% is preferred for the upper crust high conductive anomaly. [ABSTRACT FROM AUTHOR]

• SDS stabilizer and ultrasonication gives better dispersion of GNP in Saline media. • The surface tension of GNP-Saline nanofluids decreases with temperature. • A maximum decrease of 21 % in surface tension is found by adding GNP is saline media. • Increase in GNP wt% (0.05 - 0.25) in nanofluid have no impact on surface tension. The dispersions of engineered nanomaterials in fluids have envisioned numerous industrial applications. Despite less experimental data available on the surface tension of nanofluids, it is one of the critical parameters to define thermal configurations and two-phase transport properties. This study focuses on the benchmark experimental investigation of the surface tension behavior in graphene nanoplatelets-based saline nanofluids in ambient air using the pendant drop method. Graphene nanoplatelets are dispersed in saline fluid (30PPT) using optimum anionic SDS stabilizer and ultrasonication, exhibiting excellent stability for minimum 72 h. Different characterizations are performed for nanoplatelets and nanofluid stability such as electron microscopy, FTIR, XRD, DLS and sedimentation analysis. Surface tension measurements are taken at varying concentrations of graphene nanoplatelets range of 0-0.25 wt% and temperature range of 25−65 °C. The obtained results from this research exhibit that the addition of nanoplatelets drops the surface tension of saline fluid by 21 %. However, the increase in concentration from 0.05 wt% to 0.25 wt% does not have a considerable implication on the overall surface tension behavior. It is observed that the surface tension of the saline fluid and the nanofluid decrease with the elevation in temperature. [ABSTRACT FROM AUTHOR]

Background: Critically ill patients frequently develop acute kidney injury that necessitates renal replacement therapy (RRT). At some centers, critically ill patients who are hemodynamically unstable and require RRT are treated with slow low-efficiency dialysis (SLED). Unfortunately, hypotension is a frequent complication that occurs during SLED treatments and may limit the recovery of kidney function. Hypotension may also limit the amount of fluid that can be removed by ultrafiltration with SLED. Fluid overload can be exacerbated as a consequence, and fluid overload is associated with increased mortality. Occasionally, intravenous albumin fluid is given to prevent or treat low blood pressure during SLED. The intent of doing so is to increase the colloid oncotic pressure in the circulation to draw in extravascular fluid, increase the blood pressure, and enable more aggressive fluid removal with ultrafiltration. Nonetheless, there is little evidence to support this practice and theoretical reasons why it may not be especially effective at augmenting fluid removal in critically ill patients. At the same time, albumin fluid is expensive. As such, we present a protocol for a study to assess the feasibility of a randomized controlled trial evaluating the use of albumin fluid versus saline in critically ill patients receiving SLED. Methods: This study is a single-center, double-blind, and randomized controlled pilot trial with two parallel arms. It involves randomly assigning patients receiving SLED treatment in the ICU to receive either albumin (25%) boluses or normal saline fluid boluses (placebo) to prevent and treat low blood pressure. Discussion: The results of this pilot trial will help with planning a larger trial comparing the efficacy of the interventions in achieving fluid removal in critically ill patients with AKI on SLED. They will establish whether enough participants would participate in a larger study and accept the study procedures. Trial registration: This trial is registered on ClinicalTrials.gov Identifier NCT03665311, registered on September 11, 2018. [ABSTRACT FROM AUTHOR]