Effect Of Dissolution Research Articles

Impacts of Surface Reconstruction and Metal Dissolution on Ru1-x Ti x O2 Acidic Oxygen Evolution Electrocatalysts.

Improved oxygen evolution reaction (OER) electrocatalysts based on an additional understanding of surface changes that occur upon metal dissolution are needed to enable the efficient use of electrochemical water splitting. This work integrates theoretical and experimental studies of the effects of metal dissolution from the RuO2 and Ru1-x Ti x O2 surfaces on the OER activity and electrochemical stability. Our computational analysis shows that the energetic barriers for metal dissolution depend highly on the surface site and Ti-substituent location. Metal dissolution induces the formation of new active surface sites with different electronic density distributions. In addition to dissolution-induced changes to the surface composition, electron density changes occur in the interfacial electrolyte components. Surface reconstruction changes the activation barriers for the OER steps. Our experimental analysis of RuO2 and Ru0.8Ti0.2O2 using a two-step durability test in acidic electrolytes shows that the OER activity, surface, and metal dissolution change over the durability tests. Ti-substitution exhibits improved electrochemical stability with cycling. For RuO2, changes in the mass activity of RuO2 with cycling are directly correlated with Ru dissolution and lowering of the electrochemical surface area (ECSA). In contrast, Ru0.8Ti0.2O2 showed a 19 times lower Ru dissolution rate, and metal dissolution results in increasing the ECSA and new active sites. Our STEM and EELS analysis supports that repeated cycling under OER conditions results in surface reconstruction for both RuO2 and Ru0.8Ti0.2O2, with the formation of a disordered RuO2 surface and changes to the distribution of Ru and Ti at the Ru0.8Ti0.2O2 surface. The experimentally observed changes in activity and surface structure after cycling are consistent with computational analysis, which shows how metal dissolution may alter the OER activation barriers. Combining experimental and computational insights, this work reveals the effects of metal dissolution on the surface atomic and electronic structure and OER activity and advances our comprehension of metal dissolution dynamics and surface reconstruction, which may have implications for other catalytic processes.

A Review of Surface Reconstruction and Transformation of 3d Transition-Metal (oxy)Hydroxides and Spinel-Type Oxides during the Oxygen Evolution Reaction.

Developing efficient and sustainable electrocatalysts for the oxygen evolution reaction (OER) is crucial for advancing energy conversion and storage technologies. 3d transition-metal (oxy)hydroxides and spinel-type oxides have emerged as promising candidates due to their structural flexibility, oxygen redox activity, and abundance in earth's crust. However, their OER performance can be changed dynamically during the reaction due to surface reconstruction and transformation. Essentially, multiple elementary processes occur simultaneously, whereby the electrocatalyst surfaces undergo substantial changes during OER. A better understanding of these elementary processes and how they affect the electrocatalytic performance is essential for the OER electrocatalyst design. This review aims to critically assess these processes, including oxidation, surface amorphization, transformation, cation dissolution, redeposition, and facet and electrolyte effects on the OER performance. The review begins with an overview of the electrocatalysts' structure, redox couples, and common issues associated with electrochemical measurements of 3d transition-metal (oxy)hydroxides and spinels, followed by recent advancements in understanding the elementary processes involved in OER. The challenges and new perspectives are presented at last, potentially shedding light on advancing the rational design of next-generation OER electrocatalysts for sustainable energy conversion and storage applications.

Multiscale Analysis of Corrosion Fatigue Crack Propagation Mechanism of High‐Strength Steel in Seawater Atmospheric Environment

ABSTRACTE690 high‐strength steel is widely used in ocean engineering due to its excellent properties. However, it is highly susceptible to fracture and failure under the coupled effects of corrosion and fatigue in marine environments. This paper investigates the corrosion fatigue fracture mechanisms through experimental and theoretical analyses. First, a series of corrosion fatigue tests on E690 steel specimens were conducted to study the crack propagation behavior, and the crack growth parameters were fitted using the Paris equation. Second, scanning electron microscopy was employed to analyze the corrosion fracture characteristics of the E690 steel specimens. Lastly, finite element analysis and molecular dynamics simulations were used to examine the crack propagation process and failure mechanisms from multiscales. The results show that under the influence of corrosion, dislocation accumulation at the crack tip leads to a plastic deformation mechanism dominated by dislocations during crack propagation. Furthermore, the combined effects of anodic dissolution and hydrogen embrittlement accelerate crack growth. In dry air conditions, loading frequency has no significant impact on the crack growth rate, whereas, in corrosive environments, the coupling of low frequency and corrosion shortens the corrosion fatigue life.

Optimization of FSW input parameters for dissimilar butt-welded joints of Al6061-AZ31 alloys by GRA

In this paper, the optimization of Friction Stir Welding (FSW) parameters used to produce dissimilar non-ferrous butt joints of Al6061 and AZ31 alloys is investigated carefully. FSW parameters including tool rotation speeds (TRS) ranging between 700–1100 rpm, traverse speed (TS) 40–80 mm/min, and axial load (LA) 7–11 KN are considered for finding suitable FSW parameters. The experiments are carried out at different combinations of FSW parameters and the results are measured using respective equipment. The L18 orthogonal array of Taguchi design of experiments is adapted for Grey relation analysis (GRA) multi-objective optimization aiming for high tensile strength and less wear rate with measured responses. Based on grey relational grade, TRS, TS, and axial load of 1100 rpm, 60 mm/min, 9KN are found to best suitable FSW parameters with reasonable tensile strength of 132.43 MPa, microhardness of 70.4 Hv, and lower wear rate of 5.156 mm3/m, respectively. The confirmatory test has been performed to verify the finding of the optimization study with a maximum error percentage of 2%. Furthermore, the corrosion analysis has also been performed for the produced FSW butt joint at a suitable parametric combination. Corrosion behavior is improved due to equiaxed grain distribution and formed hard Mg2Si precipitates that reduce the differential dissolution effect when embedded in Al matrix. It signifies the improvement in chemical inertness in application to extreme temperature environments.

Research on solubility, solvent effect and thermodynamics analysis of Lisinopril dissolution and molecular dynamics simulation

Research on solubility, solvent effect and thermodynamics analysis of Lisinopril dissolution and molecular dynamics simulation

Durability of a thermally decomposed iridium(IV) oxide–tantalum(V) oxide coated titanium anode in aqueous ammonium citrate

Abstract Ti/IrO2–Ta2O5 coated anodes were widely used in the production process of aluminum foil that is vital raw material for high-performance electronic components, exhibits excellent service durability in sulfuric acid medium, but its lifespan is significantly reduced when used in ammonium citrate neutral electrolyte. The evolution of constant current accelerated lifetime process of Ti/IrO2–Ta2O5 anodes in 100 g/L ammonium citrate aqueous solution was systematically studied. The corrosion mechanism was revealed by physical characterization and electrochemical measurements. During electrolysis, IrO2 was gradually dissolved due to the interaction of IrO2 coating and the electrolyte. Consequently, the corrosion mechanism of the compact IrO2–Ta2O5 coating is the effect of substantial dissolution of the active components.

Parental union dissolution and children’s emotional and behavioral problems: addressing selection and considering the role of post-dissolution living arrangements

Abstract Increasingly children whose parents no longer live together are living in two households, alternating between family contexts. A growing literature documents strong, descriptive heterogeneities in children’s wellbeing across living arrangements. We combine longitudinal survey and administrative population data on 6000 Danish children born in 1995 to study how children’s emotional and behavioral problems change following parental union dissolution. Extending the existing, predominantly descriptive literature, we use several panel regression strategies that aim to control for unobservable confounding together with repeated measurement of the Strength and Difficulties Questionnaire to study children’s problems increase after parental union dissolution and examine heterogeneity across post-dissolution living arrangements. We find a substantial increase in emotional and behavioral problems following union dissolution, but only little evidence for substantial heterogeneity existing across post-dissolution family constellations and living arrangements. Our findings indicate that not only there is casual effect of parental union dissolution on children’s long-term wellbeing, but also that existing descriptive findings on differences across living arrangements likely are due to selection.

Experimental Study of Geochemical Interaction of Carbon Dioxide With Formation Water and Rock of Water-Saturated and OilSaturated Horizons

The paper presents results of the experimental study of geochemical processes in the “formation water – CO – rock” system at reservoir conditions for waterand oil-saturated intervals of several typical terrigenous and carbonate formations of Urals-Volga region. Compositions of formation water and dissolved gas are analyzed at each stage of the experiments, as well as mineral composition of core samples before and after the interaction. Based on the experimental results, a summarizing analysis is presented of possible physical and chemical processes occurring in the “formation water – CO2– rock” system during carbon dioxide injection into waterand oil-bearing formations. The results of the experiments allow us to highlight the significant effects of dissolution and resuspension of carbonates and halite during exposure of carbonized formation water with core material of different lithology and saturation character. In a number of experiments, significant changes in the iron and sulfate anions content were recorded, indicating the interaction of the solution with pyrite and gypsum. There were no significant qualitative and quantitative differences in the results of experiments with core material from water-saturated and oilsaturated intervals of the same lithology.

Characterizing broad-band seismic dispersion and attenuation in carbonates with fractures and cavities: a numerical approach

SUMMARY Carbonates are highly heterogeneous and commonly develop large-scale fracture-cavity systems due to the strong diagenesis effect of dissolution, faulting and karstification. Understanding the seismic wave velocity and attenuation signatures is crucial for hydrocarbon exploration and recovery, carbon capture, geothermal exploitation and groundwater management using seismic methods. Nevertheless, due to the sample size limitation, traditional core-scale experiments and sonic logs fail to effectively unravel the essential factors controlling elastic and anelastic responses of those carbonates with large-scale heterogeneity. We developed a 2-D geology-constrained method for constructing digital rock models of carbonates with fracture-cavity systems, integrating outcrop data and statistical analyses. Using finite element simulations based on Biot's quasi-static equations of poroelastic consolidation, we examine the effects of cavity shape, size and number, as well as fracture number, length, width and angle, on wave dispersion and attenuation characteristics. Deep carbonate rocks with fracture-cavity systems exhibit wideband attenuation spanning over three orders of magnitude (from < 0.01 to >10 Hz), driven by coupled pore pressure relaxation mechanisms in the heterogeneous system. Horizontal attenuation was found to be roughly five times greater than vertical attenuation (as fractures are predominantly in a semi-vertical direction), highlighting significant attenuation anisotropy. While cavities have minimal effects on attenuation, fracture density and geometry—especially longer and narrower fractures—significantly influence wave dispersion and attenuation behaviour. These results underscore the importance of integrating both seismic velocity and attenuation data to enhance reservoir characterization reliability, and highlight the potential of using comprehensive broad-band seismic data and large-offset seismic data to improve geophysical interpretations of complex deep carbonate reservoirs.

PRINCIPLES OF FAMILY LAW: A multidisciplinary literature review

This article addresses the changes in Family Law, focusing on shared custody and its relationship with the principle of the best interests of the child. The topic emerges as relevant in view of contemporary social and legal challenges, marked by the dissolution of marital bonds and the emotional and psychological impacts on children and adolescents. The central question of the study is: how is the shared custody model implemented in contexts of family breakdown and how does it contribute to ensuring the well-being of the minors involved? The main objective is to analyze the effectiveness of the shared custody institute in Brazil, exploring its capacity to guarantee the rights of children and adolescents. To this end, the work seeks to: (i) understand the evolution of the concept of family and its relationship with parental authority; (ii) study the legal framework that supports shared custody; and (iii) assess civil liability in cases of non-compliance with parental obligations, especially in situations of parental alienation. The methodology used consists of a bibliographic and documentary review, supported by a qualitative approach. Books, scientific articles, legislation, case law, and academic documents published between 2007 and 2021, in Portuguese and English, were analyzed. The method allowed for a broad and critical view of the topic, connecting theoretical foundations to legal practices. It is concluded that shared custody is a model that promotes cooperation between parents and preserves emotional ties with children, helping to minimize the adverse effects of family dissolution. However, its effectiveness depends on the parents' commitment to the principle of human dignity and the best interests of the child. The research reinforces the importance of a humanized and interdisciplinary Family Law that protects the rights and integral development of children and adolescents, promoting balance and justice in family relationships.

Illite Dissolution under Sodium Hydroxide Solution: Insights from Reactive Molecular Dynamics.

In alkali/surfactant/polymer (ASP) flooding systems, alkalis react with clay minerals such as Illite, montmorillonite, and kaolinite, leading to reservoir damage and impacting oil recovery rates. Therefore, studying the dissolution effects of strong alkalis on clay minerals is crucial for improving oil recovery. This study uses Illite as a representative clay mineral and employs the ReaxFF reactive force field and molecular dynamics simulations to model its dissolution in NaOH solution. We investigated the diffusion coefficients of metal cations in Illite and their interactions with hydroxide ions at various NaOH concentrations. The study also explores the evolution of dissolution products and protonation characteristics during the dissolution of Illite. By calculating the changes in ionic energy throughout the dissolution process, we analyzed variations in ionic reactivity within the system. Simulation results show that as the NaOH concentration increases, metal cations in Illite form stable chemical bonds with hydroxide ions, creating highly aggregated clusters with strong ionic interactions that hinder migration. Consequently, the diffusion coefficients of metal cations gradually decrease. During the reaction, water dissociates to produce hydrogen ions and hydroxide ions. Ion exchange occurs between the solution cations and Illite cations. Illite cations gradually precipitate and form metal hydroxides by combining with hydroxide ions under electrostatic forces. Protonation propagates from the surface to the internal structure during the reaction. Moreover, the degree of protonation increases with higher NaOH concentrations. Changes in the average ionic energy before and after the reaction indicate that K+ exhibits the highest reactivity. Intermediate silicate products are unstable in NaOH solution, with some Si4+ ions showing higher energy and stronger reactivity.

Thermochemical effects in hydrogen production with a dissolvable aluminum anode system

This study presents the results of experimental determination and theoretical calculations of the thermal effect of aluminum dissolution in alkaline solutions accompanied by hydrogen evolution. The experiments were conducted using an EK1 calorimeter, with temperature measurements recorded every 10 seconds. Potassium hydroxide solutions with concentrations ranging from 0.5 to 5 mol/L were utilized. It was demonstrated that the temperature variation curves over time, the temperature dynamics at different solution concentrations, and the aluminum dissolution rate exhibit an S-shaped profile. The rate of aluminum dissolution in aqueous alkaline solutions depends on the KOH concentration. As the KOH concentration increases from 0.5 to 2 mol/L, the thermal effect of the reaction rises. Further increasing the alkali concentration to 5 mol/L results in almost no change in the thermal effect. The thermal effect of aluminum dissolution in 3–5 mol/L sodium hydroxide solutions was found to be 1300 J/g. The experimentally determined thermal effect falls within the range of values calculated from thermodynamic data (from 1165 to 1528 J/g). The results obtained in this study can be applied to the development of relatively low-cost hydrogen production technologies.

Modeling and analysis of the effects of age hardening, magnesium dissolution, and SiC reinforcement on wear properties in eutectic Al-Si composites using full factorial techniques

Abstract This study aims to explore the effects of age-hardened traces, magnesium (Mg) dissolution, and silicon carbide (SiC) reinforcement on the wear properties of eutectic aluminum-silicon (Al-Si) matrix composites, focusing on optimizing their performance for industrial applications. A systematic investigation was conducted using a full factorial experimental design, with analysis of variance (ANOVA) performed through Minitab software to quantify the individual and interactive effects of these factors on the wear rate and coefficient of friction (COF). The results demonstrated that age-hardened traces significantly enhance wear resistance by promoting the formation of finely dispersed hardening precipitates at moderate ageing temperatures, while over-ageing negatively impacts performance due to precipitate coarsening. SiC reinforcement emerged as a key factor in improving wear resistance, attributed to its high hardness and superior abrasion resistance. The role of Mg dissolution was found to be multifaceted, contributing to solid solution strengthening and grain refinement but also interacting with other variables in complex ways. The study concludes that the optimal combination of 1.5% Mg, 4% SiC, and a peak ageing temperature of 100 °C achieves the best balance between wear resistance and frictional performance. These findings offer valuable insights into the design of high-performance Al-Si composites, highlighting the importance of microstructural control to meet the demands of advanced engineering applications.

In vivo MRI of hyperpolarized silicon-29 nanoparticles.

The objective of the present work was to test the feasibility of in vivo imaging of hyperpolarized 50-nm silicon-29 (29Si) nanoparticles. Commercially available, crystalline 50-nm nanoparticles were hyperpolarized using dynamic polarization transfer via the endogenous silicon oxide-silicon defects without the addition of exogenous radicals. Phantom experiments were used to quantify the effect of sample dissolution and various surface coating on T1 and T2 relaxation. The in vivo feasibility of detecting hyperpolarized silicon-29 was tested following intraperitoneal, intragastric, or intratumoral injection in mice and compared with the results obtained with previously reported, large, micrometer-size particles. The tissue clearance of SiNPs was quantified in various organs using inductively coupled plasma optical emission spectroscopy. In vivo images obtained after intragastric, intraperitoneal, and intratumoral injection compare favorably between small and large SiNPs. Improved distribution of small SiNPs was observed after intraperitoneal and intragastric injection as compared with micrometer-size SiNPs. Sufficient clearance of nanometer-size SiNPs using ex vivo tissue sample analysis was observed after 14 days following injection, indicating their safe use. In vivo MRI of hyperpolarized small 50-nm SiNPs is feasible with polarization levels and room-temperature relaxation times comparable to large micrometer-size particles.

Numerical Simulation of Reactive Flow in Fractured Vuggy Carbonate Reservoirs Considering Hydro-Mechanical-Chemical Coupling Effects

Summary Fractured vuggy carbonate reservoirs are critically important, contributing significantly to hydrocarbon reserves and production. The presence of fractures and vugs distinctly influences fluid flow and transport within carbonate rocks, differentiating fractured vuggy carbonate reservoirs from most other geological formations. Apart from matrix carbonate rocks, isolated fractured vuggy carbonate reservoirs are still the targets for acid stimulation due to the limited contribution of isolated fractures and vugs to fluid flow capacities. This study is motivated to investigate the acid stimulation process in isolated fractured vuggy carbonate reservoirs. In this work, the classical two-scale continuum model has been extended to describe the transport and reactive dissolution processes within complex media comprising matrix, fractures, and vugs. The discrete fracture model and the Navier-Stokes equation are used to respectively characterize fluid transport in the fractures and vugs regions. Fluid interactions between different regions are governed by the extended Beavers-Joseph-Saffman (BJS) interface conditions. Dynamic boundary conditions are applied to describe the dissolution and deformation behaviors at the boundaries of vugs. In addition, Biot equations are utilized to specifically examine the mechanical responses within the poroelastic region during the acid stimulation process. A finite element model has been developed, incorporating an effective loosely coupled sequential iterative scheme for the numerical discretization and solution of the coupled hydrological-mechanical-chemical control equations. The simulation results show that the presence of fractures and vugs in carbonate formations does not perturb the equilibrium conditions necessary for wormhole formation, thereby preserving the dissolution patterns associated with a specific acid injection rate. Nevertheless, mechanical stress shows a significant influence on fracture closure behavior. The stress-induced alteration in the acid flow and dissolution structures necessitates an increased pore volume to breakthrough (PVBT) to attain comparable dissolution effects. The increment in acid breakthrough volume finally escalates both the operational costs and complexity.

Mechanism of microfracture propagation under mechanical–chemical coupling conditions considering dissolution

Mechanism of microfracture propagation under mechanical–chemical coupling conditions considering dissolution

A reaction kinetics approach to model the spreading of oil drop on aqueous surfactant solutions

A reaction kinetics approach to model the spreading of oil drop on aqueous surfactant solutions

Multifunctional Effect of Carbon Matrix with Sulfur Dopant Inspires Mixed Metal Sulfide as Freestanding Anode in Sodium-Ion Batteries.

As active materials for large-radius Na+ storage, metal sulfide (MS) anodes still face several challenges, including poor intrinsic electric conductivity, severe volume change along with the shuttle and dissolution effects of discharge-produced polysulfides. In this work, the mixed nickel-manganese sulfides (NiMnS) in the morphology of uniform 2D ultrathin nanosheets are derived from layered metal-organic frameworks (MOFs), where the NiS-MnS heterojunction are accommodated in carbon matrix with S dopant (NiMnS/SC). Through experiments and density functional theory (DFT) simulations, it is revealed that the carbon matrix with S dopant has multifunctional effects on active NiMnS during the charge/discharge process, including conductive intermediary, electrochemical active site, physical barrier, and chemical adsorption. This work may promote the design of MS-based electrodes in SIBs and extend the application of carbon material with S dopant in Na-S batteries.

The Mesoscopic Damage Mechanism of Jointed Sandstone Subjected to the Action of Dry–Wet Alternating Cycles

The effect of the dry–wet cycle, characterized by periodic water level changes in the Three Gorges Reservoir, will severely degrade the bearing performance of rock formations. In order to explore the effect of the dry–wet cycle on the mesoscopic damage mechanism of jointed sandstone, a list of meso-experiments was carried out on sandstone subjected to dry–wet cycles. The pore structure, throat features and mesoscopic damage evolution of jointed sandstone with the action of the dry–wet cycle were analyzed using a-low-field nuclear magnetic resonance (NMR) technique. Subsequently, the impact on the mineral content of dry–wet cycles was studied by small angle X-ray scattering (SAXS). Based on this, the mesoscopic damage mechanism of sandstone subjected to dry–wet cycles was revealed. The results show that the effects of the drying–wetting cycle can promote the development of porous channels within sandstone, resulting in cumulative damage. Besides, with an increase in dry–wet cycles, the proportion of small pores and pore throats decreased, while the proportion of medium and large pores and pore throats increased. The combined effects of extrusion crush, tensile fracture, chemical reaction and dissolution of minerals inside the jointed sandstone contributed to the development of mesoscopic pores, resulting in the increase of porosity and permeability of rock samples under the dry–wet cycles. The results provide an important reference value for the stability evaluation of rock mass engineering under long-term dry–wet alternation.

Atomic insights into the ductile–brittle competition of cracks under dissolution

Atomic insights into the ductile–brittle competition of cracks under dissolution