Concentrated Solutions Research Articles

Effect of solute concentration on the number of NaCl particles generated by millimeter- and micron-sized droplets

Salt particles generated by aerosol generator are commonly used in air filtration test. As a common phenomenon, the number of generated particles increases with the salt concentration in the atomization solution. Thus far, the dependence of the particle number on the concentration of the atomization solution is not fully understood. In this study, two hypotheses were proposed to explain this phenomenon: i) a single droplet generates multiple solid particles, and the generated particle number is influenced by the salt concentration, and ii) the original droplet number increases with an increase in the salt concentration of the atomization solution. By observing the particle formation process of the levitated millimeter-scale NaCl droplet, one droplet was found to generate one particle in free air. However, whether these results are applicable to micrometer-scale droplets remains to be determined. In situ measurements were performed to detect the size distributions of the original droplets generated by the atomization solutions with various salt concentrations. A more concentrated atomization solution induced a higher number of original droplets. Particle formation patterns of droplets on glass substrates and filaments were demonstrated. Traditional observation methods for droplet drying are unsuitable for studying the particle formation of atomized droplets because of the large difference in droplet size and the existence of external forces.

Removal of Iron and Copper Ions and Phenol from Liquid Phase by Membrane Based on Carbonaceous Materials.

The present work reports an effective method for the removal of inorganic and organic pollutants using membranes based on different carbonaceous materials. The membranes were prepared based on cellulose acetate (18 wt. %), polyvinylpyrrolidone as a pore-generating agent (2 wt. %) and activated carbon (1 wt. %). Activated carbons were developed from residues after extraction of the mushroom Inonotus obliguus using microwave radiation. It has been demonstrated that the addition of activated carbon to the membranes resulted in alterations to their physical properties, including porosity, equilibrium water content and permeability. Furthermore, the chemical properties of the membranes were also affected, with changes observed in the content of the surface oxygen group. The addition of carbon material had a positive effect on the removal of copper ions from their aqueous solutions by the cellulose-carbon composites obtained. Moreover, the membranes proved to be more effective in the removal of copper ions than iron ones and phenol. The membranes were found to show higher effectiveness in copper removal from a solution of the initial concentration of 800 mg/L. The most efficient in copper ions removal was the membrane containing urea-enriched activated carbon.

Kinetics of hydrate formation by CO2 and mixture of CO2–C3H8 in concentrated NaCl solution: Effect of impellers

Hydrate-based desalination (HBD) can apply directly to high-salinity water produced with crude oils and gases. For HBD technology to be commercialized, the slow kinetics of hydrate formation must be overcome. This study investigates the effects of type, diameter, number and clearance of impellers on kinetics, i.e. nucleation and growth, of hydrates of pure CO2 and mixture of CO2–C3H8 in a stirred vessel. Concentrated saline solution (8 wt%) was applied to form hydrates at constant temperatures (271.15–279.15 K) and pressures (1.73–3.6 MPa). Single pitched blade (PB) and straight blade (SB) impellers and also dual combinations of them were applied. With both SB and PB impellers at single mode, lower clearance improved nucleation rates (lower induction times) and higher clearance improved growth rates. The growth rate with SB was higher than that with PB under similar conditions, showing that radial flow is in favor of growth rate. With dual combination of PB and SB, higher nucleation and growth rates were observed compared to single impellers. The presence of PB in dual configuration influenced only the nucleation rate. Using a large diameter SB impeller, resulted in higher growth rate and gas consumption in dual mode. The results with CO2–C3H8 mixture were the same as pure CO2. Due to the promoting effect of propane on nucleation and growth rates, the effects of variation in propeller characteristics became minor in the presence of propane.

Impact of surfactants on SWCNT dispersion in N-methylmorpholine N-Oxide for cellulose dissolution

A well dispersed slurry of single-walled carbon nanotube (SWCNT) and 60 % hydrated N-methylmorpholine N-oxide (NMMO) solution was prepared by probe sonicator. The proper dispersion of carbon nanotube (CNT) has been verified by optical microscope by varying the sonication time. Further, the slurry was concentrated to 76 % (for cellulose dissolution) and during this process some agglomeration of CNTs has been observed. The dispersion of CNT aggregation was checked by addition of surfactants like sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS) (with 2 % (w/w) with respect to CNT) to the surface of CNT. SDBS is giving better dispersion as compared to SDS when the slurry is heated to obtain 76 % NMMO as checked by optical microscope and UV–Vis spectrophotometer to get quantitative amount of dispersed CNT. 88 % dispersion has been obtained in case of SDBS-assisted CNT after heating followed by centrifugation of the concentrated solution. Similarly, 78 % dispersion has been observed in case of SDS-assisted CNT and 46 % dispersion in case of CNT without any surfactant. The stronger dispersion ability of SDBS could improve its use for SWCNT separation in NMMO solution which can be used further for cellulose dissolution to prepare lyocell fiber.

Optimization of Fe/Ni, Fe/Cu bimetallic nanoparticle synthesis process utilizing concentrated Camellia sinensis extract solution and activity evaluation through methylene blue removal reaction

In this study, we introduce a synthesis process of bimetallic nanoparticles (BNPs) Fe/Ni and Fe/Cu utilizing concentrated Camellia sinenis extract that was optimized with a solvent ratio of ethanol/H2O 4/1 (v/v), a metal ratio of 5/1 (w/w), a total polyphenol content (TPC) in the solution of 12.5 g.l−1, pH = 3–4, 25 °C, and the reaction time ranging from 30 min to 50 min. The structural and morphological characteristics of the resulting materials were determined using several techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive x-ray spectroscopy (EDX), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS). The maximum removal efficiency of methylene blue (MB) by BNPs Fe/Ni and Fe/Cu materials was found to be 88.60% and 91.06%, respectively, at a concentration of MB = 25 mg.l−1 and 25 °C. According to the results of the kinetic modeling study, the adsorption process of MB on the two BNPs materials followed second-order kinetics, with the maximum adsorption capacities of MB on Fe/Ni and Fe/Cu BNPs being 26.94 mg.g−1and 28.00 mg.g−1, respectively.

Composite ellipsoids to model charge anisotropy in particle-scale simulations of kaolinite

This paper outlines a new approach to use coarse-grained molecular dynamics (CGMD) and the Gay–Berne (GB) potential to simulate the compression of kaolinite saturated with water at an acidic pH ( = 4) in a low (1 mM) ion concentration solution. To overcome the limitations of the standard GB potential and capture the charge heterogeneity on the surface of kaolinite particles under acidic pH conditions, each clay platelet is modelled using a two-ellipsoid composite particle. The molecular dynamics software Large-scale Atomic/Molecular Massively Parallel Software was employed to generate virtual monodisperse samples containing 1000 composite particles and to simulate isotropic compression at 100 kPa. The observed macro-scale response in void ratio–effective stress space lay above the response obtained in a simulation that used an equivalent CGMD model developed to simulate alkaline (pH = 8) pore water conditions. This is in qualitative agreement with available experimental data for one-dimensional compression. A post-compression qualitative observation of two virtual samples revealed a book-house-type fabric in the sample with acidic pore fluid, whereas a turbostatic-type fabric was observed when an alkaline pore fluid was simulated. These observations are also in qualitative agreement with scanning electron microscopy data reported in the literature.

Polysaccharide Hydro-Gel from Arid Plant Seed

There is a limited information on the structure and gelation process in mucilagepolysaccharides because of the complex conformation and non-homogeneity of the constituent polysaccharides that typically show large molecular weights in excess of 1 MDa. Only a few works have been done in this area of characterizing mucilage structure and rheological behaviour for different gel solutions. Exploring this area would surely open the new horizons for drug delivery, soil conditioning and pharmaceutical industry. In this study, we aimed to extract polysaccharides found in P.ovata Seed (Isabgol) via mucilage extraction controlling molecular weight of polymers in hot water extraction stage and tried to formulate gel formation dissolving different conc. of extracted freeze-dried material along with the characterization of gel network through Rheological studies and Dynamic Light Scattering (DLS) studies in different solvents. The study confirmed the relationship between molecular associations, chain relaxation time and entanglement behaviour of P. ovata hot water extracted (HW) solutions using polydispersity index and shear rheology. Moreover, two power law regions obtained for different concentration solution are of great importance because of their wide applications in the industrial prospective.

Effect of Varied NaCl Soaking Treatment on Chemical Composition of Lesser Yam Flour and Its Use in the Production of Gluten-Free Noodles

In order to reduce dependence on wheat flour, it was necessary to use alternative options, such as lesser yam flour. The production of lesser yam flour consisted of soaking yam tubers in NaCl solutions of different concentrations (20% and 25%). This soaking process was necessary for enhancing the physical characteristics of the flour, resulting in reduced mucus and a whiter appearance. The diverse NaCl concentrations during soaking significantly affected chemical composition of lesser yam flour, impacting parameters, including moisture, ash, fat, total protein, reducing sugar, total sugar, glucomannan content, and calories. However, no discernible effect was observed on the crude fiber and carbohydrate content. In comparison to the 25% NaCl, the 20% NaCl had lesser yam flour with lower moisture, ash, protein, total sugar, and reducing sugar content, but higher fat, glucomannan, and calories. The 25% NaCl soaked lesser yam flour was selected for the production of gluten-free dry noodles. Dry noodles were prepared with various proportions of lesser yam flour and mocaf flour, including 0:100 (TG0), 50:50 (TG1), 50:40 (TG2), 70:30 (TG3), 80:20 (TG4), and 90:10 (TG5). An increase in the proportions of lesser yam flour resulted in increased hardness and chewiness, along with decreased springiness and cohesiveness. Therefore, lesser yam could be processed into flour by soaking in NaCl solutions to produce better flour, with the optimal flour composition being 80% lesser yam flour and 20% mocaf flour for gluten-free noodles production. This suggested the potential for further development of lesser yam flour as a raw material for the production of gluten-free noodles.

Mechanical Characterization of Vial Strain During Freezing and Thawing Operations Using Amorphous Excipients

The purpose of this study was to investigate the mechanical stresses and strains acting on pharmaceutical glass tubing vials during freezing and thawing of model pharmaceutical formulations. Strain measurements were conducted inside of a laboratory-scale freeze-dryer using a custom wireless sensor. In both sucrose and trehalose formulations at concentrations between 5 % and 20 % w/v, the strain measurements initially increased before peaking in magnitude at temperatures close to the respective glass transition temperatures of the maximally freeze concentrated solutes, Tg’. We attribute this behavior to a shift in the mechanical properties of the frozen system from a purely elastic glass below Tg’ to a viscoelastic rubber-like material above Tg’. That is, when the interstitial region becomes mechanically compliant at temperature above Tg’. The outputs were less predictable below 5 % w/v and tended to exhibit two separate peaks in strain output, one near the equilibrium melting temperature of pure ice and the other near Tg’. The peaks merged at concentrations between 4 and 5 % w/v where the largest strain magnitude was observed. The strain on primary packaging has traditionally been applied to evaluate the risk of damage or breakage due to, for example, crystallization of excipients. However, data collected during this study suggest there may be utility in formulation design or as a process analytical technology to minimize potentially destabilizing stresses and strains in the frozen formulation.

Testing mixing rules for structural and dynamical quantities in multi-component crowded protein solutions.

Crowding effects significantly influence the phase behavior and the structural and dynamic properties of the concentrated protein mixtures present in the cytoplasm of cells or in the blood serum. This poses enormous difficulties for our theoretical understanding and our ability to predict the behavior of these systems. While the use of course grained colloid-inspired models allows us to reproduce the key physical solution properties of concentrated monodisperse solutions of individual proteins, we lack corresponding theories for complex polydisperse mixtures. Here, we test the applicability of simple mixing rules in order to predict solution properties of protein mixtures. We use binary mixtures of the well-characterized bovine eye lens proteins α and γB crystallin as model systems. Combining microrheology with static and dynamic scattering techniques and observations of the phase diagram for liquid-liquid phase separation, we show that reasonably accurate descriptions are possible for macroscopic and mesoscopic signatures, while information on the length scale of the individual protein size requires more information on cross-component interaction.

Elastoplastic properties of ion exchangers based on cross-linked polyelectrolytes

In this paper, we dilatometrically studied the elastoplastic properties of spherical grains of industrial weakly acidic and strongly acidic ion-exchanger in experiments with constant uniaxial compression and a subsequent unload at room temperature, depending on the ionic form and concentration of the electrolyte solution. It was found that the ionic form of polyacrylate and polymethacrylate cross-linked with triethylene glycol dimethacrylate and divinylbenzene, respectively, and the concentration of the external solution affects their elastoplastic properties. In dilute solutions of sodium chloride and calcium chloride, the gels exhibited elastic properties with close relative amplitudes of deformation. The amplitude of deformation of the grain of polymethacrylate crosslinked with divinylbenzene, in the Ni form, in a dilute nickel chloride solution was significantly lower than that of the Ca form, with significant plastic deformation. With an increasing concentration of the external solution of calcium and nickel chlorides under mechanical load on the grain of polymethacrylate cross-linked with divinylbenzene, the total deformation of the granule and the magnitude of elastic deformation decreased, while the residual (plastic) deformations increased. In concentrated solutions of CaCl2 and NiCl2, such an ion-exchanger became an inelastic rigid material. Even under increased mechanical load, the magnitude of its elastic compressive deformation was very small. The K-form of a swollen in water strongly acidic polystyrene cation-exchanger with grafted sulpho groups cross-linked with divinylbenzene is also characterized by elastic deformations, i.e. the polymer is in a highly elastic state. However, the polystyrene matrix is more rigid compared to polyacrylic and polymethacrylic cation-exchangers in the alkali metal ion form, so the amplitude of deformation is significantly smaller. For such a cation-exchanger in Ca- and Ni- forms, elastic deformations prevail even in concentrated solutions.

A new concept of ternary aqueous electrolytes based on lithium 4,5-dicyanoimidazolate hydrates

A new concept of aqueous electrolytes based on heterocyclic anions (hydrated anionic triplet electrolyte, HATE) has been presented. Structural studies showed that dimeric lithium 4,5-dicyanoimidazolate (LiTDI) dihydrate molecules, in the presence of acetonitrile, form an ionic system preserved in high concentrations and solid states. X-ray diffraction measurements show that electroneutral dihydrate units can coordinate additional lithium cations acting as charge carriers. The crystalline ionic phase was characterized using spectroscopic, thermal, and electrochemical methods and was used to prepare model electrolytes based on LiTDI hydrates. Linear sweep voltammetry and impedance spectroscopy measurements show, in this system, the depletion of water activity, high conductivity, and reversible cycling of full cells comprising examined electrolytes. We will prove that a concentrated triplet solution acts similarly to the anhydrous electrolyte; regardless of the concentration, it reaches high ionic conductivity values (12–16 mS/cm at room temperature) and is electrochemically stable.

HPLC analysis of synthetic dyes in wastewater

The analysis of synthetic dyes in wastewater is an urgent task of modern analytical chemistry since an increased content of dyes in wastewater can have an adverse effect on the environment. Reverse phase high performance liquid chromatography (RP HPLC) is often used to control the content of dyes in various objects, which makes it possible to reliably determine the content of specified substances. The purpose of this work was to create and evaluate the metrological characteristics for the method of analysis of synthetic dyes in the industrial wastewater with a high content of inorganic salts. The chromatographic system used in this work was a Knauer high-pressure pump. The separation was performed on a Kromasil 100-5-C18 (w) reverse phase column (4.6 × 250 mm) in the gradient elution mode. Acetonitrile and ammonium acetate solution were used as the mobile phase. Synthetic dyes were detected on an Azura diode array detector. The paper presents the results of concentrating 10 synthetic dyes on commercially available solid phase extraction cartridges that were suitable for working with aqueous solutions with a high content of inorganic salts. For each substance, the degree of concentration from distilled and model wastewater was calculated, which varied from 2 to 98%. Among the analysed cartridges, the highest degree of concentration during operation in conditions close to real wastewater was shown by the Diapak P cartridge, at a pH of the concentrated solution equal to 4. The results of this study were used to develop and validate a method for a simultaneous detection of 10 synthetic food dyes (SFD) (E102, E104, E110, E122, E124, E129, E131, E133, E142, E151) in aqueous and organic solutions. The results of the study can be used to provide analytical control of the content of synthetic dyes in the industrial wastewater. The limit of intermediate precision of the method did not exceed 5%, and the expanded uncertainty of the measurements was less than 10%.

Microscopic experimental study on the effects of NaCl concentration on the self-preservation effect of methane hydrates under 268.15 K

It is known that salt ions are abundant in the natural environment where natural gas hydrates are located; thus, it is essential to investigate the self-preservation effect of salt ions on methane hydrates. The dissociation behaviors of gas hydrates formed from various NaCl concentration solutions in a quartz sand system at 268.15 K were investigated to reveal the microscopic mechanism of the self-preservation effect under different salt concentrations. Results showed that as the salt concentration rises, the initial rate of hydrate decomposition quickens. Methane hydrate hardly shows self-preservation ability in the 3.35% (mass) NaCl and seawater systems at 268.15 K. Combined the morphology of hydrate observed by the confocal microscope with results obtained from in situ Raman spectroscopy, it was found that during the initial decomposition stage of gas hydrate below the ice point, gas hydrate firstly converts into liquid water and gas molecules, then turns from water to solid ice rather than directly transforming into solid ice and gas molecules. The presence of salt ions interferes with the ability of liquid water to condense into solid ice. The results of this study provide an important guide for the mechanism and application of the self-preservation effect on the storage and transport of gas and the exploitation of natural gas hydrates.

HYDROCHLORINATION OF GLYCERIN

A study of the hydrochlorination of glycerol. In the current conditions, the development of alternative technologies for the synthesis of epochlorohydrin has become very relevant. Such technologies include a process based on the hydrochlorination of glycerol, especially since in recent years the chemical products market has been saturated with glycerol, a waste product of biodiesel production. However, the development of such technology requires the solution of a number of physico-chemical problems related to the hydrochlorination of glycerin and its chlorohydrides, dehydrochlorination of highly concentrated solutions of glycerin dichlorohydrins, as well as the establishment of the kinetics of the reactions of glycerol and esterification of acetic acid. In particular, we can talk about the effect of water as a solvent on the rate of reactions. This is all the more important because the data presented in the literature on the kinetics of hydrochlorination reactions of glycerin and its chlorohydrins are contradictory and inadequately describe the process over the operating temperature and concentration ranges. It can be assumed that understanding the physical chemistry of such processes and determining the characteristics of the kinetics of the reactions occurring during the production of epichlorohydrin from glycerin will provide an opportunity to choose the optimal conditions for the implementation of the process, including the type of reactors, operating temperatures, initial concentrations, proportions of reagents, etc. Keywords: Glycerin, hydrochlorination, chlorohydrides, epichlorohydrin.

Effects of Nanoconfinement on Dynamics in Concentrated Aqueous Magnesium Chloride Solutions.

Water behavior in various natural and manufactured settings is influenced by confinement in organic or inorganic frameworks and the presence of solutes. Here, the effects on dynamics from both confinement and the addition of solutes are examined. Specifically, water and ion dynamics in concentrated (2.5-4.2 m) aqueous magnesium chloride solutions confined in mesoporous silica (2.8 nm pore diameter) were investigated using polarization selective pump-probe and 2D infrared spectroscopies. Fitting the rotational and spectral diffusion dynamics measured by the vibrational probe, selenocyanate, with a previously developed two-state model revealed distinct behaviors at the interior of the silica pores (core state) and near the wall of the confining framework (shell state). The shell dynamics are noticeably slower than the bulk, or core, dynamics. The concentration-dependent slowing of the dynamics aligns with behavior in the bulk solutions, but the spectrally separated water-associated and Mg2+-associated forms of the selenocyanate probe exhibit different responses to confinement. The disparity in the complete reorientation times is larger upon confinement, but the spectral diffusion dynamics become more similar near the silica surface. The length scales that characterize the transition from surface-influenced to bulk-like behavior for the salt solutions in the pores are discussed and compared to those of pure water and an organic solvent confined in the same pores. These comparisons offer insights into how confinement modulates the properties of different liquids.

Colored noise in GRACE total water storage time series: Its impact on trend significance in the Türkiye region and major world river basins

Temporal correlations are prevalent in most geophysical time series data, leading to what is known as colored noise, which become more apparent in the frequency domain rather than time domain. Neglecting this type of noise in modeling can result in underestimated standard errors for the parameters of the model used to analyze the time series. As a result, statistical tests misinterpret the significance of these parameters, such as the overall trend rate, because the “signal to noise” ratio becomes incorrectly larger than it should be. In this study, we investigate the temporal correlations in the time series data from the Gravity Recovery and Climate Experiment (GRACE) mission. GRACE and its successor mission GRACE Follow-On (GRACE-FO) have been successfully employed to monitor global total water storage anomalies over two decades since its initial launch in 2002. We primarily utilize monthly GRACE mascon (mass concentration) solutions provided by NASA Goddard Space Flight Center (GSFC), examining both regional and global scales. The power spectrum density of the residuals, calculated after applying standard harmonic regression to each mascon time series on Earth’s land, reveals an average spectral index of κ = −1. This indicates the predominance of flicker noise, one of the most common forms of colored noise in geodetic time series. Notably, the noise becomes more Brownian (κ < −1) in regions with intense hydrological events, while it tends to be more white noise (κ → 0) in areas with less water circulation compared to other land regions. This observation suggests that unmodelled hydrological events, such as droughts, floods, and ones associated with ice-melting, contribute to the residuals as colored noise in the time series. To account for this noise in our time series modeling, we primarily consider autoregressive (AR) moving average (MA) process, commonly known as ARMA, in addition to the standard variance component estimation for noise amplitudes. We focus on individual mascon blocks in the Türkiye Region and mascon solutions for 24 world’s major river basins. Our findings demonstrate that an ARMA(1,1) model is sufficient for describing the noise in these regions. The results underscore the importance of considering colored noise, as it leads to approximately three times larger standard errors for the overall trend rate. This substantially impacts the significance of the trend rates.

#2122 Dynamics of peritoneal transport and peritoneal dialysis outcomes

Abstract Background and Aims Volume overload is one of the most important factors associated with cardiovascular disease in peritoneal dialysis (PD) patients. On the other hand, the dynamics of peritoneal transport predicts important changes in the peritoneal membrane associated with local and systemic inflammation, which may be important for the progression of cardiovascular disease. The changes in free water transport (FWT) over time can characterize the development of peritoneal fibrosis. In a prospective study with retrospective historical control, the influence of the initial status and dynamics of peritoneal FWT on the outcomes of peritoneal dialysis, hard and surrogate cardiovascular outcomes was evaluated. Method According ISPD Recommendations (2021) the function of peritoneal membrane solute transfer was evaluated in classical PET in the exchange of 2 liters of 2.5% glucose solution with the calculation of the creatinine D/P4 ratio, which was used in the analysis as a continuous value (peritoneal solute transfer rate - PSTR), as well as categorized into high, medium-high, medium-low and low (H, HA, LA, L, respectively) levels of peritoneal transport. The mass transfer coefficient (MTAC) was also calculated. The ultrafiltration function of the membrane and its dynamics were evaluated by measuring the transport of water through small pores and free water through ultrapores, in double mini-PET (in two one-hour exchanges with solutions of 4.25% and 1.5% glucose). FWT is the calculated value; the primary measured value is the degree of reduction of sodium in the dialysis solution one hour after the start of the exchange (dipNa) formed as a result of electrolyte-free water transport through ultrapores (aquaporins), which dilutes dialysate. Results Table 1 shows the average values of peritoneal transport indicators at the beginning of follow-up and the annual changes calculated over the entire period of prospective follow-up for each patient. Major adverse cardiovascular events (Table 2) were recorded with a relatively low frequency, but significantly differed by incidence between the subgroups with high (H) and high-average (HA) peritoneal transport, on the one hand, and low-average (LA) and low(L), on the other: 0.626 ± 0.049 vs. 0.320 ± 0.042 events per year; p&amp;lt;0.001, (49% fewer events). Similarly, there was a significant difference in the MACE incidence between patients with slow and rapid decrease in free water transport (divided by the median of the rate of in free water transport decrease): 0.414 ± 0.044 vs. 0.510 ± 0.051 events per year; p &amp;lt; 0.001, (19% fewer events). The same calculations for nonfatal cardiovascular events showed a fewer incidence of 47.2% and 17.1%, respectively. Thus, patients with a high transport status (according to the PET test) and patients with a rapid decrease in water transport through aquaporins (indicating an increase in fibrotic changes in the peritoneal mesothelium), accompanied also by an increase in peritoneal permeability to solutes, including glucose, are at greater risk of progression of cardiovascular disease. Conclusion In addition to confirming the link between the initial status of peritoneal transport and the subsequent incidence of cardiovascular events, it would be interesting to confirm the influence of cardiovascular disease (as a proinflammatory condition and as a factor of volume overload, forcing the wider use of concentrated solutions which damage the peritoneum) on the progression of peritoneal fibrosis, but according to available materials it was not possible due to the limited number of patients in the study (especially – patients with repeated assessments of peritoneal transport after the cardiovascular events) and low frequency of peritoneal transport monitoring, on the one hand, and uncertainty in identifying the exact time of development of heart failure and the need for revascularization. Continued prospective observation would clarify these links.

Prediction of bubble departing diameter in pool boiling of mixtures by ANN using modified ReLU

In this research, bubble departure diameter in pool boiling have been measured in aqueous amine and ethylene glycol solutions for various concentrations. The experimental data have been compared with major existing predictive correlations. It is shown that the effect and identity of the independent variables on bubble diameter proposed in the previous studies are inconsistent. The predictions of different correlations have on average a deviation of about 40% from the experimental data. This is mainly due to the complicated interactions between bubbles on the heterogeneous boiling medium, which provides a complex condition. This complexity limits any mathematical modelling of the forces acting on the developing bubbles. Particularly in liquid solutions, where mass transfer by back diffusion through micro-sub-layers adds further complexity. In this work, the classical artificial neural network, ANN, with rectified linear unit, ReLU, activating function, AF, has been modified. This modification is based on adding a numerical matrix to each layer to adjust the slope of AF for each neuron independently. The addition of this parameter, together with the adjustment of the bias matrix, makes the activation function more flexible than the classical ReLU. To find the tuning parameters, a genetic algorithm was implemented instead of the back-propagation technique. It is shown that the predictions of the trained ANN with modified ReLU AF agree within an absolute average error of 10%, which is equal to the total uncertainty of the measurements. Prediction of bubble departing diameter in boiling phenomena is a key parameter for accurate design, operation and optimisation in many industrial systems.

A study on soil aggregate stability and splash erosion under exogenous electrolyte conditions in the karst region of Southwest China

Study areaKarst region in Guangxi Province, Southwest China. Study focusBoth soil properties and rainfall characteristics have a critical influence on splash erosion and aggregate stability. However, the impact of electrolytes on splash erosion has received less attention. In this study, soils from 4 typical land use types (cropland, orchard, artificial forest and secondary forest) in karst region were utilized as the research objects. NaCl, KCl, and MgCl2 solutions of different concentrations were used to determine the stability of the aggregates via fast wetting (FW) treatment of Le Bissonnais (LB) method and the characteristics of splash erosion via simulated rainfall experiments. New hydrological insights for the regionResults revealed that both the land use types and electrolyte significantly influenced the soil aggregate stability and splash characteristics. Specifically, the change in land use from cropland to orchard, artificial forest and secondary forest significantly increased the aggregate stability, thus decreasing soil erodibility. The aggregate stability decreased and the total splash rate increased as the electrolyte concentration increased. The total splash erosion rate of the 4 soils was positively correlated with the <0.5 mm particle size released by aggregate fragmentation under simulated rainfall conditions. The results can provide a theoretical basis for soil erosion control and soil quality improvement in the karst region of Southwest China.