Decrease In Surface Tension Research Articles

Thermophysical Assessment of Lead Magnesium Alloy at Different Temperatures

Abstract: The mixing behavior of lead–magnesium liquid alloy is studied using different modeling equations at various temperatures. The quasi-lattice model has been employed too analyze the concentration-dependent thermodynamic and structural properties of lead–magnesium liquid alloy. To validate the model, the obtained theoretical results are compared with experimental results. The viscosity of the alloy has been studied by the Kozlov–Romanov–Petrov equation, the Kaptay equation, and the Budai–Benko–Kaptay model, whereas surface tension has been studied by the Butler equation, tatistical mechanical approach, and the Compound formation model. The primary focus of this study is the interaction parameters among the atoms of the alloy. The alloy shows the moderately interacting and ordering nature within the entire concentration of lead. There is reasonable agreement between the theoretical and experimental data at 973K. The study concludes that the alloy depicts ordering tendency and viscosity and surface tension both decrease with increase in temperature. Keywords: Ordering, Complex formation, Asymmetric, Statistical mechanical approach.

Study on Dynamic Contact Behavior of Multi-Component Droplet and Dust Surface

The dynamic contact behavior between multi-component droplets and the surface of iron ore dust was taken as the research object, analysis of the maximum spreading coefficient, maximum acting diameter, maximum acting area, and maximum bouncing height of solid-liquid contact, from a microscopic perspective, using high-speed photography and image analysis and processing technology. The experimental results indicate that (1) with the particle size of dust particles decreases, the solid-liquid contact behavior sequentially manifests as spread immediately after broken, retraction, negative bounce, primary bounce, and secondary bounce. (2) When the surface tension of the droplets decreases from 55.5 to 34.8 mN/m, the maximum spreading diameter of the droplet has increased by 30% to 40%, the maximum bounce heights (coefficients) decreased by 100%, 57.14%, and 53.57%, respectively, the maximum spreading coefficient of the droplet exhibits no obvious pattern. (3) With decreasing droplet surface tension, the unidirectional acting diameter and the maximum acting area increase when the dust surface size is over 100 μm. When the surface particle size is less than 100 μm, there is no significant change in the unidirectional acting diameter and maximum acting area despite decreasing surface tension. Thus, droplet diffusion is mainly influenced by particle size. These findings contribute to enhancing the theory of water mist dust removal and improving dust removal efficiency.

INVESTIGATION OF MODIFIED POLYACRYLAMIDE FOR OIL DISPLACEMENT

At present, the use of surfactants and water-soluble polyelectrolytes, which act as stabilizing and selective agents, is inextricably linked with the successful solution of the technological issues in the world of chemical, oil and other industries. The purpose of the work is to synthesize and study the physicochemical properties of modified polyacrylamide with gossypol resin and further crosslinking in the presence of potassium persulfate and sodium sulphate to displace oil. Methods. To establish the spectral characteristics of the modified PAA, IR spectra have been taken on an IR-Fourier spectrometer. For the structural-elemental composition (SEM), a Jeol JSM-6490l V electron microscope has been used. The viscosity of modified PAA solutions has been measured in a Ubellode capillary viscometer with a hanging level. Results and discussion. The studies, carried out by the authors of the study of the colloid-chemical properties of polymer composites, allow us to conclude that the reagents obtained during the hydrolysis of vat residues of fatty acids distillation with sodium hydroxide with further cross-linking in the presence of potassium persulfate and sodium sulphate have good surfaceactive and emulsifying properties, which is important when displacing oil from layers. The surface tension of polymer compositions has been studied. With an increase in the concentration of the solution, the surface tension decreases, i.e., the surface activity increases. Conclusion. The research results show that the injection of a polymer reagent solution can increase the oil displacement efficiency by 6-7%.

Determination of Critical Micelle Concentration of Sodium Dodecyl Sulfate in Distilled Water at 298.15K by Surface Tension Measurements

Surfactants are chemicals that adsorb to the interface between a solution and another phase (gases or solids) and self-assemble molecular clusters known as micelles in a solution (water or oil phase). Measurements of the surface tension of sodium dodecyl sulfate (SDS) in distilled water at 298.15K are reported. The increase of concentration of sodium dodecyl sulfate (SDS) in distilled water then decreased in surface tension at 298.15K. Critical micelle concentration (CMC) decreased with a decrease in surface tension. The graphs of surface tension versus concentration were made to determine the CMC of the solution.

Capillary nanowaves on surfactant-laden liquid films with surface viscosity and elasticity

Nanofilms are susceptible to surfactant contamination. This work investigates surfactant effects on nanowave dynamics on a bounded film with a finite depth, using both molecular dynamics simulations and analytical theories. It is shown that the presence of surfactants leads to a slower decay of surface mode temporal correlations, which, however, cannot be predicted by only considering the decreased surface tension due to the added surfactants. Based on the Boussinesq--Scriven model for surface viscosity, a linear stability analysis of Stokes flow for films with arbitrary depth is conducted. The obtained dispersion relation considering surface viscosity can justify the simulation results.

Effect of Sodium Carboxymethyl Cellulose on the Dynamic Wetting Characteristics of the Dust Suppression Droplet Impacting the Coal Surface.

The dynamic wetting behavior of droplets impacting the coal surface directly affects the efficient application of water-based dust suppression materials in coal-related industrial production. In this paper, ultrapure water, Tween-80, and sodium carboxymethyl cellulose are taken as the research objects. Using high-speed photography technology, the spreading, oscillation process, and splash morphology of many kinds of droplets during impacting the coal surface are captured. The effects of viscosity, surface tension, and impact velocity on dynamic wetting characteristics were studied. The results show that with the decrease of surface tension, the retraction and oscillation of droplets are significantly reduced. For the same kind of droplets, the greater the impact velocity, the faster the droplet spread, and the dimensionless maximum spreading coefficient (βmax) and dimensionless steady-state spreading coefficient (βe) of droplets are bigger. With the increase of velocity, the time for different kinds of droplets to reach the βmax increases. At the same impact velocity, βmax and βe of droplets (0.2% Tween-80 + 0.1% sodium carboxymethyl cellulose) are the largest, indicating that adding a small amount of sodium carboxymethyl cellulose can promote droplet spreading. With the increase of sodium carboxymethyl cellulose content, βmax and βe decreased gradually. The results have a great significance to the research, development, and scientific utilization of water-soluble polymer dust inhibitors.

Stability and rheological properties of foams co-stabilized by hydrophilic silica nanoparticles and amino acid/alkyl glycoside surfactants

Foams stabilized by nanoparticles (NPs) and surfactants have potential applications in the development of new environmentally friendly firefighting foams. In the present study, the mixed dispersions of anionic amino acid surfactant (SLG), nonionic alkyl glycoside surfactant (APG0810), and silica NPs were prepared. The influence of silica NPs on foamability, foam drainage, foam coarsening, and foam rheological properties of the mixture of SLG/APG0810 was systematically investigated. Results indicate that the presence of NPs results in decrease in conductivity and surface tension of the mixed dispersion. The viscosity of the mixed dispersions slightly decreases and then increases, while the foamability decreases following an increase with increasing NP concentration. The apparent viscosity of the mixed dispersions decreases over shear rate. The increase in NP concentration leads to rapid increase in viscoelastic modulus of the mixed dispersions and foams. The presence of NPs with concentration below 1 wt% results in acceleration of foam drainage and coarsening, while the presence of NPs with concentration above 1 wt% leads to deceleration of foam drainage and coarsening. This study offers theoretical support for the use of NPs in fluorine-free firefighting foams.

Effect of Wall Proximity and Surface Tension on a Single Bubble Rising near a Vertical Wall

Path instability of a rising bubble is a complex phenomenon. In many industrial applications, bubbles encounter walls, and the interactions between the bubbles and the wall have a significant impact on flow physics. A single bubble rising near a vertical wall was experimentally observed to follow a bouncing trajectory. To investigate the near-wall dynamics of rising bubbles, 3D numerical simulations were performed based on the volume of fluid (VOF) method using the open source solver OpenFOAM. The effect of wall proximity and surface tension on the bubble trajectory was investigated. Previous studies have focused on the near-wall rising dynamics of bubbles for higher Eotvos numbers (Eo) and varied the Galilei number (Ga). The physical properties of the flow were chosen such that the free-rising bubble lies in the rectilinear regime. The Ga number was fixed and the Eo number was varied to analyze its effect on the bubble’s rising trajectory. It was found that the presence of the wall increases the drag experienced by the bubble and induces an early transition from rectilinear to a planar zigzagging regime. We identify the maximum wall distance and the critical Eo number for the bubble to follow a bouncing trajectory. The amplitude, frequency and wavelength of the bouncing motion are independent of the initial wall distance, but they decrease with decreasing surface tension.

Decrease in the Surface Tension of Nanobubble Dispersion in Water: Results of Surface Excess of Bulk Nanobubbles at Interfaces

The effect of nanobubbles (NBs) on the surface tension of liquid was investigated by three methods of different measuring principles, pendant drop (PD), Wilhelmy, and du Noüy methods, over a wide range of number concentration of bulk NBs (BNBs). In all of the three methods, the surface tension decreased in proportion to the number concentration of BNBs and the proportional constant was different among the three methods. Such behavior was inferred to be caused by the surface excess of BNBs at the gas-liquid or solid-liquid interface. In the PD method, the hydrophobic interaction between BNBs and air around a drop seems to cause the surface excess of BNBs along the surface of water drops. It brings about a subtle change in its profile, resulting in the decrease in surface tension, which takes a time of hundreds of seconds. Meanwhile, in the Wilhelmy and du Noüy methods, electrostatic attractive force between BNBs and a plate or ring is a likely cause of surface excess at the solid-liquid interface, resulting in the instantaneous decrease in surface tension. This study also provides a practical methodology of comparison for surface tension of NB dispersion: surface tension shall be compared among different samples with the same measurement method. Especially in the PD method, retention time of droplets before measurement shall be the same among samples.

Physicochemical investigations on the interaction of an anionic surfactant with cellulose based polymer microgel

Abstract This work focuses on the interaction of cellulose-based colloidal microgel dispersions with the anionic surfactant sodium dodecyl sulfate (SDS) at different concentrations. First, a Cellulose-P(NIPAAm-MAA)-based responsive microgel sample was prepared by a radical polymerization method using a one-pot process. The samples thus obtained were purified, characterized and used to study microgel-surfactant interactions. To this end, SDS solutions with different concentrations were prepared and the interactions of SDS in the premicellar and micelle regions with polymer microgel were investigated using different physicochemical techniques. Experiments were also performed at different temperatures to obtain the degree of binding of SDS to microgel in gel surfactant mixtures. Due to the temperature-sensitive properties of microgel, we observed significant changes in various properties of microgel-surfactant mixtures when the solution temperature changed. The overall results showed that various experimental variables, such as the polymer gel/surfactant ratio and temperature, affect the gel–surfactant interaction quantitatively and qualitatively. With increasing surfactant concentration, conductance, viscosity and absorbance values ​​increased, but a decrease in surface tension was observed. This is due to the adsorption of SDS at the air-water interface. The micellar activity of surfactants is enhanced by the addition of microgels. It was found that the strength and nature of the interaction depended not only on the gel/surfactant ratio, solvent type and test temperature, but also on the chemical structure of the surfactant used. Furthermore, the visual stability of the colloidal particles in the mixture of microgel and SDS was also noticeable over time.

An Experimental Investigation of the Impact of Surface Tension and Viscosity on the Atomization Effect of a Solid Cone Nozzle

To investigate the influence of surface tension and viscosity on the atomization performance of solid cone nozzles and improve their dust reduction efficiency in industrial and mining enterprises, this study employed a self-built PDPA dust-fog coupling experimental system to explore the effects of different surface tension and viscosity solutions on atomization performance from three aspects: axial, radial, and fog field distribution. The experimental results indicate that compared with surface tension, surface tension has a greater influence on droplet size and velocity in the axial direction. In the radial direction, increasing surface tension and reducing viscosity within a certain range can make the droplet size and velocity distribution more uniform. Additionally, surface tension and viscosity significantly affect the fog field distribution. It was found that a decrease in surface tension can result in a closer proximity of the droplet velocity and size expansion area to the nozzle, while an increase in viscosity can lead to a more prolonged stable area. Furthermore, optimizing the surface tension and viscosity can significantly enhance the efficacy of dust reduction for respirable dust. Consequently, the application of the aforementioned atomization principles to regulate the fog field characteristics of solid cone nozzles can effectively mitigate dust in the production process and augment the dust reduction rate of industrial and mining enterprises.

Effect of solvents on the properties of Ag0-containing aluminosilicate sorbents for iodine capture

Radioiodine, which is generated during the reprocessing of nuclear fuel, must be immobilized on sorbents to convert it into a stable waste form. In this study, to capture iodine, Ag0-containing aluminosilicate sorbents (Ag0ASSs) were synthesized via sol–gel method using Na, Al, and Si alkoxides; co-solvent exchange; Ag/Na ion exchange; solvent exchange with solvents having different surface tensions; and ambient pressure drying. Three different Na+AlSi-OH sols were synthesized using sodium methoxide (NaOMe): aluminum tri-sec-butoxide [Al(OsBu)3]: tetraethyl orthosilicate (TEOS) with molar ratios of 1.05:1:1, 1.3:1.1:1, and 1.5:1.3:1. The solvent effect on textural properties such as surface area and pore size distribution, Ag0 particle size, and total iodine capture capacity of Ag0ASSs was investigated using two types of solvents: 1) a solvent with high surface tension (water) and 2) solvents with low surface tension (isopropanol and n-heptane). The textural properties and particle size distribution of Ag0 in the Ag0ASSs were dependent on the type of solvents used for exchange. The average pore diameter and cumulative pore volume of the Ag0ASSs, except the Brunauer–Emmett–Teller (BET) surface area, significantly increased with decreasing surface tension of solvent and increasing Al/Si atomic ratios. Although the increase in pore diameter and volume resulted in larger particle sizes of Ag0 in Ag0ASSs, the total and chemisorbed iodine-capture capacities of the Ag0ASSs increased. Therefore, the total and chemisorbed iodine-capture capacities depends on the pore size distributions of the Ag0ASSs. These Ag0ASSs have the potential to immobilize radioiodine, which could be further processed into stable compounds.

Influences of hydroxylation modifications of lecithin on its surface tension and viscosity of PBX slurry

Reducing viscosity is an important factor affecting the dispersion and forming process of polymer bonded explosive (PBX). In this study, lecithin was modified by hydroxyl reaction in order to enhance its viscosity reduction effect. The structure of hydroxylated lecithin was confirmed by nuclear magnetic resonance spectroscopy (NMR), infrared spectrum (IR) and iodine values. The decrease of surface tension of styrene and the decrease of viscosity of HMX-based PBX slurry before and after modification were analyzed. The results showed that hydroxylated lecithin had better effect on reducing surface tension and viscosity.

Mutual compatibility of superplasticizers (PC, SNF), grinding aids (TEA, glycol) and C3A in Portland cement systems – Hydration, rheology, physical properties and air void characteristics

The compatibility of grinding aids (TEA/glycol) and superplasticizers (PC/SNF) in low- and high-C3A cements, as well their mutual effect on the properties of pastes and fresh/hardened mortars were evaluated. The influence of various surfactant combinations on the hydration rate, flowability, compressive strength, rheology, surface tension and air void characteristics was studied. For this purpose, 6 cements based on industrial clinkers and 18 mortars were prepared under laboratory conditions. PC is more effective than SNF in low-C3A cements. In high-C3A cements, both superplasticizers have a comparable impact on consistency. Grinding aids, especially TEA, have a strong influence on the effectiveness of PC and SNF, leading to changes in the induction period, plastic viscosity and yield stress. A synergy effect of grinding aids and superplasticizers increases the air content of mortars, especially for TEA-SNF combination. Surfactants decrease surface tension, particularly PC, thus increasing the amount of air voids >300 µm.

Enhanced treatment of m-dichlorobenzene waste gas in biotrickling filters: Performance, mass transfer and microbial community

This study aimed to investigate the performance of biotrickling filters (BTFs) in the microbial degradation of m-dichlorobenzene (m-DCB) to construct an enhanced treatment of removing m-dichlorobenzene (m-DCB) at different concentrations of rhamnolipids (RLs) and lanthanum (La3+) or neodymium (Nd3+) ions. We found a significantly enhanced removal of m-DCB when 110 mg/L of RLs and 0.2 mg/L La3+ or 0.4 mg/L Nd3+ ions were added. The addition of RLs and La3+ or Nd3+ ions increased the m-DCB average removal efficiency (101–110 days) by 19.7% and 22.7%, respectively, when the inlet m-DCB concentration was 800 mg/m3 and the empty bed residence time (EBRT) was 60 s. Further, the mechanisms that strengthened the mass transfer were the decrease of contact angle, surface tension, and Henry’s constant after the addition of RLs and La3+ or Nd3+ ions in the nutrient solution; further, we noticed a significant increase in the dissolved oxygen levels. Improvements in the performance of BTFs were associated with enhanced microbial community and an increased abundance of functional genes. In conclusion, the addition of RLs and La3+ or Nd3+ ions can enhance the performance of BTFs in degrading m-DCB by improving mass transfer and microbial activity simultaneously.

Wetting effect of branched anionic Gemini surfactant aqueous solution on PMMA surface.

In this paper, the adsorption behaviour and wetting modification ability of the sodium salts of bis-octadecenoyl succinate (GeminiC3, GeminiC6) and monomers on polymethyl methacrylate (PMMA) surfaces were investigated. The difference in spacer length led to slightly different behaviour of surfactant molecules in solution. The large molecular structure and short flexible spacer of GeminiC3 led to a complex self-aggregation behaviour in solution, forming micelles at low concentrations, leading to a rapid decrease in surface tension and subsequent transition to monolayer or multilayer vesicles. In GeminiC6, the longer flexible spacer groups act as spatial structure modifiers that hinder the formation of vesicles. The adsorption behaviour of the gas-liquid interface was analysed in three stages for the peculiar inflection points where surface tension appears. Combining contact angle measurements, adhesion tension and interfacial tension data showed that GeminiC3 and C6 formed a saturated monolayer on the adsorbed PMMA surface at low concentrations and a bilayer structure at high concentrations. Due to the low resistance of molecular space sites, the monomers adsorbed heavily on the PMMA surface, forming semi-colloidal aggregates with the lowest contact angle of monomeric surfactant solutions reaching 38° on the PMMA surface. Also, the monomer and GeminiC3 and C6 surfactants in this paper have a very high hydrophilic modification ability on the PMMA surface compared to other literature.

Effect of surface tension on elastocapillary wrinkling of interfacially adsorbed hydrogel disks with photothermally programmed swelling profiles.

In this work, we study the influence of surface tension on light-induced wrinkling of hydrogel disks containing patterned regions of photothermally-active gold nanoparticles at the air-water interface. The disks, which are initially radially stretched by the air-water surface tension, undergo wrinkling under illumination through a radially nonuniform photothermal deswelling. By tuning the surface tension of the surrounding air-water interface through variations in concentration of a poly(vinyl alcohol) surfactant, we observe a critical threshold for wrinkling, followed by a monotonic decrease in wrinkle number with decreasing surface tension. Finite element simulations performed to better understand this behavior reveal qualitatively similar trends as the experiments. The insights provided into elastocapillarity-mediated wrinkling may guide future efforts to control interfacial behaviour of reconfigurable and shape-morphing films.

Experimental study of the stable droplet formation process during micro-valve-based three-dimensional bioprinting

Three-dimensional (3D) bioprinting offers great potential for the fabrication of complex 3D cell-laden constructs for clinical and research applications. The droplet formation process is the important first step in droplet-based 3D bioprinting, affecting the positional accuracy and printing fidelity. In this paper, the drop ejection behavior, thresholds for stable droplet generation, and formation of satellite drops are studied, under various ink properties, printing conditions, and input cell concentrations using a micro-valve-based 3D bioprinter. Three droplet ejection behaviors are identified under different conditions: an isolated stable droplet, satellites coalescing into a single droplet, and the presence of one/multiple satellites. The droplet state is represented by a phase diagram bounded by a dimensionless Z number (the inverse of the Ohnesorge number) and a jet Weber number, Wej, to define the printability of the utilized bioprinter. The printability range is defined as 2 < Z < 15 and 10 < Wej < 25 by considering characteristics, such as stable single droplet formability and sufficient drop falling velocity. There is no fatal damage on cells within this printability range. The results show there is no strong influence of an actuation system on droplet-based bioprinting printability. As the input cell concentration increases, the bioink's density and viscosity increases, and surface tension decreases, which, in turn, causes the Z number to slightly decrease. The change in the cell concentration (from 0 to 1×107 cells/ml), within a Newtonian bioink, has negligible impact on the droplet volume, falling velocity, drop ejection behavior, breakup time, and ligament length in microvalve-based bioprinting.

Experimental study of density, molar volume and surface tension of the liquid Ti-V system measured in electromagnetic levitation

Systematical experimental data on density, molar volume and the surface tension, measured in electromagnetic levitation, has been summarized for the liquid Ti-V system. The optical dilatometry method as well as the oscillating drop technique have been employed to investigate the temperature- and compositional dependence. A linear decrease in density and surface tension with increasing temperature has been observed for all investigated compositions. Pure Vanadium shows hereby the highest density and surface tension while pure titanium shows the lowest density and surface tension respectively. Therefore, the density and surface tension decrease with increasing titanium content, however not linear. Since no excess quantities were available, simple models could be employed to cover the complete liquid Ti-V system. Experimental data as well as the corresponding linear fits are presented.

On the rebound of soapy drops.

Pure water is known to bounce on super-hydrophobic materials, and we discuss here whether this remains true if the surface tension of water is lowered by either alcohol or surfactants. After determining the threshold in surface tension below which drops stick to the substrate, we show that a decrease of surface tension makes the rebound slower, a consequence of the reduced stiffness of this kind of spring. We also report that water with "slow" surfactants can still bounce despite a static surface tension smaller than the rebound threshold, which is interpreted as an effect of dynamic surface tension. The liquid is substantially deformed at impact, which impoverishes the surfactants at the its surface and thus can trigger repellency for a wetting liquid.