Separation Process Research Articles

Monomer-mediated growth of β-cyclodextrin-based microporous organic network as stationary phase for capillary electrochromatography.

CD-MONs (β-cyclodextrin-based microporous organic networks), derived from β-cyclodextrin, possess notable hydrophobic characteristics, a considerable specific surface area, and remarkable stability, rendering them highly advantageous in separation science. This research aimed to investigate the utility of CD-MONs in chromatography separation. Through a monomer-mediated technique, we fabricated an innovative CD-MON modified capillary column for application in open-tubular capillary electrochromatography (OT-CEC). The CD-MON-based stationary phase on the capillary's inner surface was analyzed using Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). We assessed the performance of the CD-MON modified capillary column for separation purposes. The microstructure and pronounced hydrophobicity of CD-MON contributed to enhanced selectivity and resolution in separating diverse hydrophobic analytes, such as alkylbenzenes, halogenated benzenes, parabens, and polycyclic aromatic hydrocarbons (PAHs). The maximum column efficiency achieved was 1.5 × 105 N/m. Additionally, the CD-MON modified capillary column demonstrated notably high column capacity, with a methylbenzene mass loading capacity of up to 197.9pmol, surpassing that of previously reported porous-material-based capillaries. Furthermore, this self-constructed column was effectively utilized for PAHs determination in actual environmental water samples, exhibiting spiked recoveries ranging from 93.2 to 107.9% in lake water samples. These findings underscore the potential of CD-MON as an effective stationary phase in separation science.

Influence of Water Concentration on the Water/Vapor/ Oil Separation Process in a Vacuum Oil Filter: Modelling and Simulation

The vacuum oil filter (VOF) is widely applied in the oil-water emulsion demulsification separation due to the phase separation by using vacuum evaporation; however, the micro-dynamic characteristics of oil, water and vapor three phases and the influencing factors of separation efficiency are rarely studied. Therefore, the fluid flow and phase separation characteristics of water-in-oil emulsions were numerically analysed by ANSYS software. The demulsification conditions of water/oil emulsion were simulated by using the two-fluid model and the water evaporation model, and the turbulence effect was considered by using the Reynolds stress model. The results show that the established model could provide a convenient way to study the effects of the different water concentrations in oil; the turbulence intensity in VOF increases with the increase of water concentration in oil; The separation efficiency has been influenced by the inlet water concentration reaching values between 20.65-22.62% in the center axis, while 33.18-42.24% in the plate column; the vapor concentration ranged from 0 - 23.64% in the center axis, while 0 - 41.02% in the plate column. The relative volume fraction of water concentration decay tending with the water concentration increases, and the water concentration has a great influence on the separation efficiency.

Multifunctional membranes with super-wetting interface and in-situ Fenton-like sites for efficient oil-in-water emulsion separation

The surge in oil-in-water (O/W) emulsions poses a threat to the ecological environment. Membrane separation technology can achieve complete O/W emulsion separation through size sieving; however, its efficiency is limited by membrane fouling. In this study, an efficient O/W separation membrane with passive and positive anti-fouling properties was fabricated using Fe3O4 functionalized attapulgite (ATP) nanofibers. The anti-fouling mechanism of the multifunctional membranes for the separation of various O/W emulsions was studied. During separation process, a hydration layer, which mitigates oil adhesion with binding energy as low as −169 kcal·mol−1, forms on the interface of Fe3O4-ATP. When a cationic surfactant is present, positively charged oil droplets are attracted to the membrane surface, where they compress against each other, leading to demulsification and escape. Synergistic effects including electrostatic shielding, interaction energy, and steric hindrance were demonstrated through characterization and simulation. Our findings showed that the membrane exhibited a high filtration efficiency with an oil rejection of over 99 % and a steady flux of over 73 % of its initial value. After filtration, oil fouling degraded into smaller sizes and escaped from the membrane structure through the Fenton-like catalytic function of Fe3O4, resulting in a flux recovery ratio of up to 90 %. This study provides a reference for the construction of multifunctional membranes for efficient separation processes and advancing anti-fouling research on membrane interfaces.

Engineering ratchet-based particle separation via extended shortcuts to isothermality.

Microscopic particle separation plays a vital role in various scientific and industrial domains. Conventional separation methods relying on external forces or physical barriers inherently exhibit limitations in terms of efficiency, selectivity, and adaptability across diverse particle types. To overcome these limitations, researchers are constantly exploring new separation approaches, among which ratchet-based separation is a noteworthy method. However, in contrast to the extensive numerical studies and experimental investigations on ratchet separation, its theoretical exploration appears weak, particularly lacking in the analysis of energy consumption involved in the separation processes. The latter is of significant importance for achieving energetically efficient separation. In this paper, we propose a nonequilibrium thermodynamic approach, extending the concept of shortcuts to isothermality, to realize controllable separation of overdamped Brownian particles with low energy cost. By utilizing a designed ratchet potential with temporal period τ, we find in the slow-driving regime that the average particle velocity v[over ¯]_{s}∝(1-D/D^{*})τ^{-1}, indicating that particles with different diffusion coefficients D can be guided to move in distinct directions with a preset D^{*}. It is revealed that an inevitable portion of the energy cost in separation depends on the driving dynamics of the ratchet, with an achievable lower bound W_{ex}^{(min)}∝L^{2}|v[over ¯]_{s}|. Here, L is the thermodynamic length of the driving loop in the parametric space. With a sawtooth potential, we numerically test the theoretical findings and illustrate the optimal separation protocol associated with W_{ex}^{(min)}. Finally, for practical considerations, we compare our approach with the conventional ratchets in terms of separation velocity and energy consumption. The scalability of the current framework for separating various particles in two-dimensional space is also demonstrated. This paper bridges the gap between thermodynamic process control and particle separation, paving the way for further thermodynamic optimization in ratchet-based particle separation.

Design and multi-objective optimization of hybrid process of membrane separation and electrochemical hydrogen pump for hydrogen production from biogas

A new hybrid process for hydrogen (H2) production that including membrane separation, electrochemical hydrogen pump (EHP) and steam methane reforming (SMR) was proposed. Firstly, the combination of two different membranes (PEO-CA) is applied to upgrade the biogas and capture CO2. Secondly, to avoid the toxic effect of CO on the EHP catalyst and, more importantly, to improve the H2 purity, the reforming reaction module is supplemented with water gas shift after the SMR. Finally, EHP is used to achieve high purity hydrogen. Simultaneously, the heat and power integration are considered to improve system efficiency. Sensitivity analysis, maximal information coefficient method and response surface methodology are applied to establish the correlation between objectives and parameters. Then, the second generation multi-objective non-dominated genetic algorithm (NSGA-II) is utilized to achieve minimum levelized cost of hydrogen (LCoH) and carbon emission per unit of hydrogen (ECO2). The optimized LCoH is 2.72 $/kgH2, and the ECO2 is 3.24 kgCO2e. Multi-stage membrane carbon capture process enhances CH4 conversion in SMR. The application of EHP reduces energy consumption and enhances hydrogen yield compared to PSA. The innovative use of membrane is hybridized with EHP to achieve the system intensification. The new hybrid process has a significant advantage in terms of ECO2 (37.45% reduction), although the price is higher compared to conventional biogas-to-hydrogen processes. Thus the new process is a promising low-carbon hydrogen production process from biogas.

Ultra-hydrophilic MOF-303 on electrospun nanofibers with Burr Puzzles structure for the purification of oily wastewater containing heavy metal ions

The current oil-water separation field is extremely complex and the material system is variable. Therefore, the full process applicability of membrane technology is extremely demanding, both in terms of high oil-water separation efficiency and the treatment of soluble substances in wastewater, such as heavy metal ions. The high demand for membrane performance is accompanied by the complexity of the membrane manufacturing process, resulting in the development of membrane technology being hindered. If we can purify heavy metal ions from wastewater while meeting the conditions of oil-water treatment, and simplify the process flow, it is an innovation that we are happy to see. Herein, the use of a seed pre-embedded growth strategy is taking polyacrylamide (PEI) as a breakthrough point, we take advantage of blending to introduce embedding sites in polyacrylonitrile (PAN) membranes. Uniform growth of MOF-303 with Burr Puzzle structure on membrane surface using in situ hydrothermal growth method. The Burr Puzzles structure on the membrane surface is not only able to effectively deal with nanoscale stabilized oil-water mixture and effectively adsorb heavy metal ions, but also enables the MOF-303 crystals to grow more firmly on the membrane surface, so that the modified membrane still maintains good performance in harsh environments. The separation fluxes of the oil-in-water emulsions were all higher than 6987 L m−2 h−1 for oil-in-water emulsion with a separation efficiency of 98.4 %, and the adsorption efficiency of heavy metal ions was also as high as 98.3 %. After 20 cycles, the membrane maintains its promising performance. Due to its simple preparation process and excellent efficiency of emulsions separation and heavy metal ions separation, simplifies complex membrane processes while meeting the rigors of wastewater treatment. it has great prospects for development in the current complex wastewater treatment process.

Structural color of metallic glass through picosecond laser

Abstract The alteration in surface color of metallic glasses (MGs) holds great significance in the context of microstructure design and commercial utility. It is essential to accurately describe the structures that are formed during the laser and color separation processes in order to develop practical laser coloring applications. Due to the high oxidation sensitivity of La-based metallic glass, it can broaden the color range but make it more complex. Structure coloring by laser processing on the surface of La-based metallic glass can be conducted after thermoplastic forming. It is particularly important to clarify the role of structure and composition in the surface coloring process. The aim is to study the relationship between amorphous surface structural color, surface geometry, and oxide formation by laser processing in metallic glasses. The findings revealed that the periodic structure primarily determines the surface color at laser energy densities below 1.0 J/mm2. In contrast, the surface color predominantly depends on the proportion of oxides that are formed when energy densities exceed 1.0 J/mm2. Consequently, this study provides a novel concept for the fundamental investigation of laser coloring and establishes a new avenue for practical application.

Radiochemical separation of 161 Tb from neutron irradiated Gd target by liquid-liquid extraction technique

Abstract No-carrier-added (NCA) 161 Tb, which has advisable nuclear properties to be applied for cancer radiotherapy was produced at the Egyptian Second Research Reactor (ETRR-2) by neutron irradiation of natural gadolinium target via indirect nuclear reaction. The radiochemical separation of 161 Tb from irradiated gadolinium target was investigated based on solvent extraction technique using Cyanex 302. Several separation parameters were checked and optimized. According to the obtained results, the separation process of the investigated radioisotopes proceeds in two steps. The first step is an extraction of all of them into the organic phase in which the extraction % (98 %) was optimized at pH 4, 0.15 M of Cyanex 302 and 2.5 h extraction time. Moreover, the slope analysis method confirmed the participation of 2 mol of the organic extractant for the separation of 161 Tb from irradiated gadolinium. The second step is the separation of the 161 Tb isotope that was purified by the stripping of 159Gd with a citrate solution at pH 9, which is considered as a highly efficient and promising method for separation and purification of the two radioisotopes.

The phase field method coupled with molecular dynamics parameter for simulating phase separation behavior of SBS modified asphalt

Polymer-modified asphalt is a thermodynamically unstable system, in which the polymer and asphalt are prone to phase separation. Due to the inadequacy of characterization methods for phase separation, this field has not been thoroughly understood or explored. This paper introduces an innovative methodology by employing a simulation approach that couples phase-field theory with molecular dynamics parameters. Using SBS polymer-modified asphalt as an example, validate the method's applicability and establish a more precise parameter library for the phase separation field model of SBS-modified asphalt. The phase separation process of SBS-modified asphalt was simulated. In combination with fluorescence microscopy experiments, the evolution of the micro and meso-phase states of the modified asphalt over time was established and tracked. Results indicate that higher light component content and lower heavy component content in asphalt improve its compatibility. Migration coefficients and interaction parameters for the phase field model were determined, and a more accurate correction factor for the entropy contribution of SBS-modified asphalt was estimated. The phase-field model shows that higher light component content and lower heavy component content result in slower and smaller phase separation, leading to better compatibility. The combined phase field and molecular dynamics simulations accurately reproduce experimental findings from fluorescence microscopy, providing theoretical references for studying phase separation in polymers.

Investigation of PVDF‐co‐HPF based ultrafiltration polymer inclusion membrane for the extraction of cadmium ions

AbstractUltrafiltration polymer inclusion membranes (UPIMs) have become increasingly significant for the separation and purification of heavy metals from industrial wastes and wastewater due to their convenience compared to other liquid membranes. A novel process for cadmium separation and recovery has been developed using biodegradable ion carriers, specifically room temperature ionic liquids with various molecular structures. This innovation has greatly enhanced the efficiency and application of UPIMs for cadmium separation, while also providing the membranes with unique functional properties. In this study, various UPIMs were produced using polyvinyl fluoride hexafluoropropylene (PVDF‐co‐HPF) as the base polymer, different plasticizers, and symmetric room temperature ionic liquids as ion carriers. The ability of these membranes to extract cadmium ions was evaluated, demonstrating a removal rate of 9.70 μmol s−1 from a 25 ppm Cd(II) solution under optimum conditions. The selectivity and stability of the optimized UPIM were examined under different conditions to obtain a deeper insight into of its performance. The morphological characteristics of the optimized UPIM were examined using scanning electron microscopy and atomic force microscopy techniques.

Ab Initio Simulation of Liquid Water without Artificial High Temperature.

Comprehending the structure and dynamics of water is crucial in various fields, such as water desalination, ion separation, electrocatalysis, and biochemical processes. While reported works show that the ab initio molecular dynamics (AIMD) can accurately portray water's structure, the artificial high temperature (AHT) from 120 to 30 K is needed to mimic the quantum nature of hydrogen-bond network from GGA, metaGGA to hybrid functionals. The AHT proves to be an inadequate approach for systems involving aqueous multiphase mixtures, such as water-solid interfaces and aqueous solutions. This is due to the activation of additional phonons in other phases, which can lead to an overestimation of the dynamics of nearby water molecules. In this work, we find that the regularized SCAN (rSCAN) functional effectively captures both the structure and dynamics of liquid water at ambient conditions without AHT. Moreover, rSCAN closely matches experimental results for the hydration structures of alkali, alkali earth, and halide ions. We anticipate that the versatile and accurate rSCAN functional will emerge as a key tool based on ab initio simulation for investigating chemical processes in aqueous environments.

Efficient enrichment and characterization of triterpenoid saponins from Platycodon grandiflorus roots

Platycodon grandiflorum roots (PGR), a widely recognized edible herbal medicine, are extensively used in traditional Chinese medicine for respiratory ailments. PGR are rich in bioactive compounds, particularly triterpenoid saponins, which possess significant pharmaceutical properties, including anti-inflammatory, antifungal, and antioxidant activities. Despite their recognized bioactivity, the purification and enrichment processes of triterpenoid saponins remain underexplored. This study aimed to optimize the extraction and purification of triterpenoid saponins from PGR to enhance resource utilization and minimize waste. Our method involved n-butanol extraction and macroporous adsorption resin, yielding four extracts with varying saponins contents. Qualitative analysis using LC-MS identified 8 triterpenoid saponins across the extracts. Further fragmentation analysis delineated characteristic ion patterns and cleavage pathways for these compounds. Quantitative analysis demonstrated that the separation and purification process effectively increased the triterpenoid saponins content, with the highest levels obtained through 30 % ethanol elution. Notably, the absence of Platycodin D in the 30 % ethanol eluate highlighted potential variations due to the origin, processing, and purification methods. These findings provide theoretical support for the development and utilization of triterpenoid saponins in PGR.

Two-Step Macromolecule Separation Process with Acid Pretreatment and High-Shear-Assisted Extraction for Microalgae-Based Biorefinery

A simple two-stage extraction and recovery method for macromolecules from microalgae biomass, termed CASS (concentrating the microalgae solution, acid pretreatment, high-shear-assisted lipid extraction, and separation), was developed. This method effectively processed the wet biomass of Chlorella sp. ABC-001 at a moderately low biomass concentration (50 g/L). The optimal conditions were acid pretreatment with 5 wt.% H2SO4 at 100 °C for 1 h, followed by high-shear extraction using hexane at 3000 rpm for 30 min. The acid pretreatment hydrolyzed carbohydrates and phospholipids, disrupting the cell wall and membrane, while high-shear mixing enhanced mass transfer rates between solvents and lipids, overcoming the hydraulic barrier at the cell surface. Within 10 min after completing the process, the extraction mixture achieved natural phase separation into water, solvent, and biomass residue layers, each enriched with carbohydrates, lipids, and proteins, respectively. The CASS process demonstrated high esterifiable lipid yields (91%), along with substantial recovery of glucose (90%) and proteins (100%). The stable phase separation prevented emulsion formation, simplifying downstream processing. This study presents the results on cell disruption, optimal acid treatment concentration, and high-shear mixing to achieve macromolecule separation, expanding the lipid-centric microalgal process to a comprehensive biorefinery concept.

Occurrence, distribution and fate of iodine during phosphate ore beneficiation process

Numerous beneficiation techniques, such as washing, grinding, flotation, digesting, and calcination, are used to concentrate the minerals found in phosphate rocks, which include apatite, carbonatites, and silicates. Significant iodine levels are often found in phosphate ore minerals, which have a distinctive geochemical occurrence. However, the exact occurrence and distribution of iodine in these minerals are not yet thoroughly understood. A study was carried out to investigate the iodine's distribution, occurrence modes (phases), and release rate in Moroccan phosphate as it undergoes the beneficiation process. The samples underwent a multi-analytical approach combining mineralogical and chemical characterization using ICP-MS, ICP-OES, XRD, elements titration, and Pearson correlation analysis for interelement relationships. Calcination, digestion, and Heavy liquid separation is used to study the fate of iodine. The analysis indicates that iodine is primarily found in fluorapatite, with local concentrations ranging from 35 to 130 ppm. The most enriched grains/zones are associated with fluorapatite, enriched in P2O5, F-. in addition, iodine is positively correlated with its main components, including P2O5, F-, SO3, Na2O, CaO, and REEs. The flotation and heavy liquid separation process used for calcite and silicate removal is acting as an iodine and P2O5 concentrator, given that 99 % of iodine occurs in the apatite phase. However, it has been demonstrated that iodine can be released during the digestion of phosphate rock. Where the initial iodine content is distributed among phosphoric acid, PG, and the gaseous phase, constituting 35 %, 25 %, and 40 %, respectively. Furthermore, the calcination of phosphate rock between 800–1000 °C shows that total iodine is released with gases in I2 form, leading to an increase in the concentration of iodine in the surrounding area. In this regard, an integrated pyrometallurgical process has been proposed for the valorization of iodine as silver iodide. This process involves trapping gaseous iodine in an alkaline solution, followed by precipitation, thereby contributing to the overarching objectives of the circular economy and environmental protection.

Applying Bronfenbrenner’s Ecological Systems Model in Family Court

he work of Urie Bronfenbrenner is a key framework in Family Science, yet there are many areas where it has seldom been applied, including in the processes experienced by divorcing families in Family Court. Acknowledging the paucity of scholarship applying ecological systems theory to these topics, the paper offers instructive interpretations of personal practice experience in these roles. Described are two of several career roles in Family Court available to professionals trained in family science and how Bronfenbrenner’s ecological systems model of development is applicable in that work. Careers described are providing training and consultation for attorneys and judges and conducting custody evaluations. Bronfenbrenner’s model affords consistent and useful principles for both roles. The processes of separation and divorce are described as a series of ecological transitions that affect not only family structure, but the relationships that make up the family system, as well as family members’ participation in other ecosystems. Changes in relationships and ecosystems affect development by requiring individuals to adapt. Family Court itself is an ecosystem with roles, activities and macrosystem beliefs that are often stressful for family members and that may increase risks to family relationships and development. Discussion considers areas where Family Scientists can use Bronfenbrenner’s model to contribute to improved research and practice for divorcing families.

Recent Advances in Synthesis, Properties, and Applications of Magnetic Ionic Liquids: A Review

AbstractMagnetic ionic liquids (MILs) are a subclass of ionic liquids that exhibit paramagnetic properties intrinsically, without the need for additional magnetic particles. These properties can be attributed to the cations, anions, or both. Typically, MILs incorporate transition or inner‐transition metals within the anion structure. These adaptable liquids demonstrate remarkable physicochemical properties, notably a robust response to external magnetic fields. The body of research concerning the synthesis, characterization, and practical applications of MILs has expanded swiftly in recent times. This review delves into the latest research on the synthesis, properties, and utilization of MILs across various domains, including catalysis, fluid‐fluid separation, polymer science, and analytical chemistry. Within the realm of analytical chemistry, MILs are pivotal, serving as solvents in various analytical procedures such as dispersive liquid‐liquid micro‐extraction, matrix solid‐phase dispersion, and single‐drop micro‐extraction. Owing to their paramagnetic nature, MILs are instrumental in the separation process, streamlining organic reactions by obviating the need for traditional extraction or centrifugation steps.

Ti3C2 quantum dots-modified oxygen-vacancy-rich BiOBr hollow microspheres toward optimized photocatalytic performance

The Ti3C2 quantum dots (QDs)/oxygen-vacancy-rich BiOBr hollow microspheres composite photocatalyst was prepared using solvothermal synthesis and electrostatic self-assembly techniques. Together, Ti3C2QDs and oxygen vacancies (OVs) enhanced photocatalytic activity by broadening light absorption and improving charge transfer and separation processes, resulting in a significant performance boost. Meanwhile, the photocatalytic efficiency of Ti3C2 QDs/BiOBr-OVs is assessed to investigate its capability for oxygen evolution and degradation of tetracycline (TC) and Rhodamine B (RhB) under visible-light conditions. The rate of oxygen production is observed to be 5.1 times higher than that of pure BiOBr-OVs, while the photocatalytic degradation rates for TC and RhB is up to 97.27% and 99.8%, respectively. The synergistic effect between Ti3C2QDs and OVs greatly enhances charge separation, leading to remarkable photocatalytic activity. Furthermore, the hollow microsphere contributes to the enhanced photocatalytic performance by facilitating multiple light scatterings and providing ample surface-active sites. The resultant Ti3C2QDs/BiOBr-OVs composite photocatalyst demonstrates significant potential for environmental applications.

On-line enrichment and separation of glycoprotein by capillary electrophoresis based on pH response coating column

A capillary column coated with 3-aminophenylboronic acid (APBA)-functionalized gold nanoparticles (AuNPs@APBA) was prepared via electrostatic self-assembly. The coated column exhibited anti-nonspecific adsorption of glycoproteins, enabling selective online enrichment during capillary electrophoresis (CE). First, gold nanoparticles (AuNPs) were synthesized using the sodium citrate reduction method. Then, APBA was self-assembled electrostatically on the surface of the AuNPs to obtain AuNPs@APBA. This nanomaterial was bonded to the inner wall of a capillary through ion adsorption to produce a AuNPs@APBA-coated capillary column. Glycoproteins were adsorbed via bond formation with boric acid groups under alkaline conditions (pH 8) to generate borate esters. Under acidic conditions (pH 3), the borate esters dissociated to release the glycoproteins, thereby achieving the selective online enrichment and separation of glycoproteins. The AuNPs and AuNPs@APBA were characterized using Fourier transform infrared spectroscopy, and their sizes and Zeta potentials were determined. In addition, the electroosmotic flow (EOF) of the AuNPs@APBA-coated capillary column was measured. The results showed that the surface of the AuNPs was successfully modified with APBA and that AuNPs@APBA was adsorbed on the inner wall of the capillary. The peak area of ovalbumin (OVA) on the AuNPs@APBA-coated column was 26.46 times higher than that on a bare column via conventional electrophoresis. In contrast, the peak area of bovine serum albumin (BSA) only increased by 8.47 times, indicating that the AuNPs@APBA coated column selectively enriched glycoproteins. Evaluation of the reproducibility and stability of this method revealed that the AuNPs@APBA coated capillary column could be used continually for 33-67 h. The relative standard deviations (RSDs) of the peak areas for intra-day (n=5) and inter-day (n=6) analyses were 2.2% and 3.0%, respectively. The developed method was successfully applied to enrich glycoproteins in a 1×106-fold diluted egg white sample. Glycoproteins were not detected using conventional electrophoresis on the bare column, whereas the AuNPs@APBA-coated capillary column effectively enriched and separated glycoproteins, resulting in a peak area of 10469 mAU·ms. Furthermore, the entire enrichment and separation process was completed within 3 min. This new online enrichment and separation method for glycoproteins has the advantages of low sample consumption, simple operation, and high separation efficiency.

Binary phase separation in strongly coupled plasma

We investigated the two-dimensional binary phase separation process of plasma species using classical molecular dynamics in the strongly coupled regime. Both the plasma species interact via a pairwise screened Coulomb (Debye–Hückel) potential; however, the screening parameter κ is different for like- and unlike-species and is the cause for phase separation. We characterize the separation process by measuring the domain growth of equilibrium phases as a function of time—generally, the more significant the inhomogeneity in pairwise interaction, the faster the domain growth. Typically, the domain growth follows a power law in time with an exponent β characterizing the underlying coarsening mechanism. We demonstrate that the growth law exponent is β=1/2 for equal-number-density mixtures and 1/3 otherwise. Further, by comparing these with the corresponding growth laws in binary mixtures of viscous fluids, we show that the viscoelastic nature of plasma fluid modifies the coarsening dynamics, which in turn leads to the observed growth law exponents, notably in the unequal-number-density case.

Architecture and anatomy of executive processes: evidence from verbal fluency and Trail Making Test in 2009 stroke patients.

The few voxel-wise lesion-symptom mapping (VLSM) studies aimed at identifying the anatomy of executive function are limited by the absence of a model and by small populations. Using Trail Making Test (TMT) and verbal fluency and a model of their architectures, our objective was to identify the key structures underlying two major executive processes, set-shifting and strategic word search. We applied a validated VLSM analysis to harmonized cognitive and imaging data from 2009 ischemic stroke patients as a part of the Meta VCI Map consortium. All contrast analyses used an adjusted threshold with 2000 Freedman-Lane permutations (p ≤ 0.05). The TMT parts A and B were associated with structures involved in visual-spatial processing, the motor system, the frontal lobes, and their subcortical connections. Set-shifting depended on the left dorsomedial frontal region. Both semantic and phonemic fluency tests depended on verbal output abilities and processing speed with similar slopes in different languages. The strategic search process depended on Broca's area, F2 and related tracts, temporal and deep regions. Lastly, the lesion map of set-shifting did not overlap with those of strategic word search processes. Our results identify the anatomical substrates of two main executive processes, revealing that they represent only a specific subpart of previously reported structures. Finally, our results indicate that executive functions depend on several specific, anatomically separable executive processes mainly operating in various parts of the frontal lobes.