Maximum Bubble Pressure Method Research Articles

Physicochemical Properties of the (LiF + CaF2)eut + LaF3 System: Phase Equilibria, Volume Properties, Electrical Conductivity, and Surface Tension

The physicochemical behavior of the molten system (LiF (1) + CaF2 (2))eut + LaF3 (3) has been studied and the phase equilibria, density and volume properties, electrical conductivity, and surface tension have been selected for investigation. Well-established methods for determination of these physicochemical properties of molten salts have been used, such as thermal analysis, the Archimedean method of hydrostatic weighing, and the phase shift and maximum bubble pressure methods. A significant change in all investigated properties was detected in the region of x3 = 0.04–0.06. In regard to phase equilibria, this region is close to and may contain the eutectic point; in volumetric properties, the initial volume contraction (on increasing mol %) starts to reverse. A sharp change of electrical conductivity reflects the changes in ionic composition, and surface tension also shows different behavior below and above this region.

Influence of Zinc on the Surface Tension, Density and Molar Volume of (Ag-Sn)eut +Zn Liquid Alloys

The dilatometric and maximum bubble pressure methods were applied for the measurements of the density and surface tension of liquid (Ag-Sn)eut+Zn lead-free solders. The experiments were carried out in the temperature range from 515 to 1223 K for the alloys of the zinc concentration equaling 0.01, 0.02, 0.04, 0.05, 0.1 and 0.2 of the mole fraction. It was found that the temperature dependence of both the density and the surface tension could be thought as linear, so they were interpreted by straight line equations. The experimental data of the molar volume of the investigated alloys were described by the polynomial dependent on the composition and temperature.Calculations of the surface tension by Butler’s equation were conducted and confronted with the experimental data. Some significant deviations between the experimental and the calculated surface tension were observed. They reached almost 40 mNm-1. The observed changes of the density and surface tension caused by the zinc addition to the Ag-Sn eutectic were discussed with the consideration of the thermodynamic properties and the influence of a small quantity of impurities in a protective gas atmosphere.

Surface tension and density data for Fe–Cr–Mo, Fe–Cr–Ni, and Fe–Cr–Mn–Ni steels

The temperature dependence of surface tension and density for Fe–Cr–Mo (AISI 4142), Fe–Cr–Ni (AISI 304), and Fe–Cr–Mn–Ni TRIP/TWIP high-manganese (16 wt% Cr, 7 wt% Mn, and 3–9 wt% Ni) liquid alloys are investigated using the conventional maximum bubble pressure (MBP) and sessile drop (SD) methods. In addition, the surface tension of liquid steel is measured using the oscillating droplet method on electromagnetically levitated (EML) liquid droplets at the German Aerospace Centre (DLR, Cologne). The data of thermophysical properties for Fe–Cr–Mn–Ni is of major importance for modeling of infiltration and gas atomization processes in the prototyping of a “TRIP-Matrix-Composite.” The surface tension of TRIP/TWIP steel increased with an increase in temperature in MBP as well as in SD measurement. The manganese evaporation with the conventional measurement methods is not significantly high within the experiments (∆Mn < 0.5 %). The temperature coefficient of surface tension (dσ/dT) is positive for liquid steel samples, which can be explained by the concentration of surface active elements. A slight influence of nickel on the surface tension of Fe–Cr–Mn–Ni steel was experimentally observed where σ is decreased with increasing nickel content. EML measurement of high-manganese steel, however, is limited to the undercooling state of the liquid steel. The manganese evaporation strongly increased in excess of the liquidus temperature in levitation measurements and a mass loss of droplet of 5 % was observed.

Synthesis and characterization of cationic colloidal unimolecular polymer (CUP) particles

Cationic colloidal unimolecular polymer (CUP) particles were prepared by using a lower concentration of the quaternary ammonium functional copolymers during the process of water reduction. True nanoscale (diameter 3–9 nm), zero-volatile organic content (VOC), spheroidal CUP particles, and self-stabilized via electro-repulsion of surface cationic groups were obtained. The viscosity of the cationic CUP systems was influenced by the electroviscous effects arising from the surface charge and the associated surface water layer. The density of surface water was 1.6 % greater than the bulk water density which was attributed to the structuring of water around charged quaternary ammonium groups. The equilibrium surface tension values decreased linearly with increasing concentration and surface charge density of CUP particles due to a greater reduction in surface energy. The rate of surface tension reduction determined by maximum bubble pressure method decreased with increasing concentration and the molecular weight of the CUP due to diffusion effects.

Dynamic surface tension and adsorption kinetics of a siloxane dicephalic surfactant

The dynamic surface tension (DST) of a siloxane dicephalic surfactant was measured by using the maximum bubble pressure method. By using the classical Ward and Tordai equation, the diffusion coefficient for each bulk surfactant concentration was calculated. The results show that at the initial adsorption stage and at the end of the adsorption process, the dynamic surface tension data were all consistent with this diffusion-controlled mechanism. Their diffusion coefficient was slightly lower than that for conventional hydrocarbon surfactants.

Equilibrium and Dynamic Surface Properties of Sulfosuccinate Surfactants

AbstractThe equilibrium and dynamic surface tension of three sulfosuccinate surfactants at the air/aqueous solution interface were investigated. Wilhelmy plate method was used to determine critical micelle concentration (CMC) and the equilibrium surface tension (γeq). The dynamic surface tensions in the range 10–100 s were measured by maximum bubble pressure method. The well‐known Ward–Tordai equation was employed to analyze the adsorption of the sulfosuccinate surfactants. The parameters and effective diffusion coefficients (Deff) of dynamic surface tension have been calculated and analyzed. The equilibrium surface tension results showed that disodium laureth (3) sulfosuccinate (AEO3‐SS), disodium laureth (6) sulfosuccinate (AEO6‐SS) and disodium alkyl ethoxy glucoside sulfosuccinate (AEG‐SS) are surfactants possessing strong surface activity, adsorbing to the interface rapidly and their γeq values were in the range 25–32 mN/m. CMC of the three surfactants increases with the number of hydrophilic groups and AEO3‐SS has the lowest CMC. According to the values of some dynamic surface tension parameters, AEG‐SS is the most hydrophilic surfactant of them and AEO3‐SS is energetically more favorable to adsorb to the interface than the others. According to Ward–Tordai equation, the Deff values were calculated, the adsorption mechanism was diffusion controlled at short times and toward the end good evidence was found for an activated‐diffusion mechanism with an energy barrier.

Adsorption characteristics of N’-undecylenamidopropyl-N”-trimethylammonium methyl sulfate at the air–water interface

The dynamic surface tension and adsorption properties of the aqueous solutions of N’ -undecylenamidopropyl- N” -trimethylammonium methyl sulfate, an eco-friendly cationic surfactant, were evaluated by a maximum bubble pressure method at various life times.

Physicochemical properties of the system (LiF + NaF + KF(eut.) + Na7Zr6F31): Phase equilibria, density and volume properties, viscosity and surface tension

The aims of the study were to investigate the physicochemical properties, such as the phase equilibria (by the means of thermal analysis), density (by Archimedean method of hydrostatic weighing), viscosity (by torsion pendulum method) and surface tension (by maximum bubble pressure method), of the (LiF+NaF+KF(eut.)+Na7Zr6F31) fluoride system. The obtained data show significant deviation from the ideal/additive behaviour, particularly in the concentration range from (0 to 20)mol% of Na7Zr6F31 while the data sets correspond each other very well. In this range a sharp increase in temperature of primary crystallisation together with volume expansion, positive deviation from “additive” behaviour of viscosity and negative deviation from “additive” behaviour of surface tension were observed. These significant changes are discussed and indicate complicated interactions of the components in the melt.

Vacuum Inert Gas Atomisation of Cr-Mn-Ni Austenitic Steel Alloys

The Cr-Mn-Ni austenitic steel cast alloys containing 16 wt.-% chromium, 7 wt.-% manganese and 3 to 9 wt.-% nickel are used as matrix material to manufacture TRIP-Matrix-Composite containing MgO partially stabilised ZrO2 ceramics. In the present work, these steel master alloys were atomised via a vacuum inert gas atomisation to provide fine grain sized metal powders for the assembling of TRIP-Matrix-Composite. The atomised steel powders where characterised according to their chemical composition and the d50 mass median particle size determined by a laser diffraction analyses. The surface tension of the liquid steel alloys was experimentally investigated using the maximum bubble pressure (MBP) method. The reference austenitic steel alloy (AISI 304) has the highest surface tension and the highest mass median particle size compared to the Cr-Mn-Ni steel alloys, where d50 values are lower due to lower surface tension values. Finally, it is concluded from the present investigation, that the d50 size of the atomised steel powders decreases by a decrease of surface tension values for the liquid steel alloys.

Phosphor Alloyed CrMnNi Austenitic As‐cast Stainless Steel with TRIP/TWIP Effect

AbstractIn the present work the influence of phosphor on the flowability, the effect on the infiltration of ZrO2 open foam ceramics and the martensite formation as well as the resulting mechanical properties of high alloyed CrMnNi as‐cast steels is studied. Additionally, the effect of phosphor on surface tension is investigated. The study is performed using thermodynamic calculations, static tensile tests, notch‐bar impact tests, optical light microscopy, scanning electron microscopy, energy dispersive X‐ray analysis, electron backscatter diffraction, and the magnetic scale for the detection of ferromagnetic phase fractions. Maximum bubble pressure method is used to measure the surface tension of the liquid steel. The martensite phase fraction is not significantly influenced with increasing phosphor content. The flowability and the quality of the infiltration of open foam ceramics are improved with increasing phosphor contents. The investigated specimens show an increasing yield and an ultimate tensile strength with higher phosphor contents. The uniform and the fracture elongation as well as the notch impact resistance remain at high values. Moreover, an increase in phosphor content did not significantly change the surface tension of the investigated CrMnNi alloys.

Bubble size distribution in flow boiling of aqueous boric acid under high pressure

The focus of this study lies on the effect of boric acid and lithium hydroxide on the bubble size distribution in flow boiling with special regard to pressurized water reactors (PWRs). Previous studies proposed effects similar to those of surface active agents. Transient and stationary measurements of the bubble size distribution with a wire-mesh sensor in a boiling loop with up to 40bar were taken. The experiments approximated many aspects of reactor conditions. In addition, the physical properties – especially surface tension – at atmospheric pressure of boric acid solutions were determined. The equilibrium surface tension was measured with the Wilhelmy plate method and the dynamic surface tension with the maximum bubble pressure method. Both measurements showed no difference to pure water, which contradicts previously published data.Two types of experiments were performed: transient experiments with the aim to simulate a fast pressure increase in a PWR and stationary experiments simulating normal, i.e. stable, operating conditions. The transient measurements of the bubble-size distribution yielded no detectable difference between deionized water and boric acid solutions. The stationary measurements showed only minor deviations in the range of small gas mass fractions, which decreased with increasing gas mass fraction. The addition of lithium hydroxide seemed to counter this effect.

Improvement and Application of the Maximum Bubble Pressure Tensiometer

In order to measure the equilibrium surface tension of blended fuels, a tensiometer based on maximum bubble pressure method was built. Microscope was used to measure the capillary internal diameter precisely. And the operation guidelines of the tensiometer were calibrated by purified water to improve its accuracy. Then, the equilibrium surface tensions of bio-ethanol diesel fuels were investigated at a wide range of temperature and mass fractions. Results show that surface tension of blend fuels decrease linearly as temperature increases and decrease monotonically while ethanol mass fraction increases.

The Thermophysical Properties of Liquid TRIP/TWIP‐Steel Alloys Using the Maximum Bubble Pressure Method

The thermophysical properties of liquid Cr‐Mn‐Ni steel alloys (16 wt% Cr, 7 wt% Mn, and 3–9 wt% Ni) are investigated using the maximum bubble pressure method in which the manganese evaporation and change in chemical composition is very low after experimental trial. The surface tension of copper was measured as reference and experimental σ is in the range of literature values. It is shown that for AISI 304 austenitic steel the surface tension decreased by an increase of oxygen concentration in steel composition. For Cr‐Ni and Cr‐Mn‐Ni steels, the temperature coefficient is positive which is explained by sulfur steel concentrations larger 50 mass ppm. A slight influence of nickel to the surface tension of Cr‐Mn‐Ni steels was experimentally observed where σ was lowered by rising weight percentage of nickel.

Effect of Surface Tension on Gas Atomization of a CrMnNi Steel Alloy

AbstractThe aim of the current research is the experimental investigation of the mass median particle size d50 as a function of surface tension for liquid Cr–Mn–Ni steel alloy with 16% Cr, 7% Mn, and 9% Ni. To modify the liquid steel design sulfur was add to the Cr–Mn–Ni steel in five steps up to a 1000 mass ppm. The surface tension of the liquid steel alloy was measured using maximum bubble pressure method and yttria stabilized capillary in a temperature range from 1701 to 1881 K. In addition, the same steel charges were sprayed to steel powder using a vacuum inert gas atomization using pure argon gas. The increase of sulfur in Cr–Mn–Ni steel will decrease the surface tension to 0.91 N m−1. The temperature coefficient of surface tension is positive for all investigated Cr–Mn–Ni alloys due to a sulfur content ≥100 mass ppm. The final mass median particle size d50 decreases from 54.3 µm for AISI 304 reference steel alloy to 17.1 µm for Cr–Mn–Ni steel alloy (16‐7‐9 S10) with the highest sulfur content and the lowest surface tension of all investigated liquid steels. It is concluded from the present work that surface tension is the decisive factor in adjusting d50 at a constant spraying parameters.

Dynamic Surface Tension of Ionic Liquid [C&lt;sub&gt;10&lt;/sub&gt;(EP&lt;sub&gt;y&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;]Br&lt;sub&gt;2&lt;/sub&gt; Using Maximum Bubble Pressure Method

The ionic liquids used in this study are (1,1’-decane-1,10-diylbis (3-ethylpyridinium) dibromide. The reason of this experiment is to figure out character of ionic liquids called green solvent. It can help to use of ILs to know that specific feature since ionic liquids are made so many different way. Using maximum bubble pressure method, we tested dynamic surface tension in range of 298K~418K and time range is 0.03s~60s. Among various method of inspecting dynamic surface tension, maximum bubble pressure is the easiest way to have such description of the solution at air/water interface. In the short time, it show only diffusion model, but in the long time range there is different aspect which it called diffusion-controlled model

Synthesis and Surface Activity of Bisphosphate Gemini Surfactants

AbstractAnionic bisphosphodiester gemini surfactants with two different spacer moieties and varying alkyl chain lengths were synthesized and investigated for their surface active properties. The equilibrium and dynamic surface tension studies were carried out using the Wilhelmy plate technique and maximum bubble pressure method respectively. It was found that these gemini surfactants possess lower critical micellar concentration values, and reduce the surface tension to a greater extent in comparison with the conventional analogues. The efficiency of the synthesized gemini surfactants was also evaluated. The results of surface activities obtained were correlated with the structures of gemini surfactants. The dynamic surface tension measurements showed that the geminis with long chains adsorb very slowly at the air/water interface within the time span of measurements. These gemini surfactants showed low foamability.

The Role of Polysorbate 80 and HPβCD at the Air-Water Interface of IgG Solutions

To test the hypothesis of surface displacement as the underlying mechanism for IgG stabilization by polysorbates and HPβCD against surface-induced aggregation. Adsorption/desorption-kinetics of IgG-polysorbate 80/-HPβCD were monitored. Maximum bubble pressure method was used for processes within seconds from surface formation. Profile analysis tensiometry was applied over long periods and to assess surface rheologic properties. Additionally, the kinetics of adsorption, desorption and surface displacement was followed by a double-capillary setup of the profile analysis tensiometer, allowing drop bulk exchange. Weak surface activity for HPβCD vs. much higher surface activity for polysorbate 80 was shown. Protein-displacement when exceeding a polysorbate 80 concentration close to the CMC and a lack of protein displacement for HPβCD was observed. The drop bulk exchange experiments show IgG displacement by polysorbate 80 independent of the adsorption order. In contrast, HPβCD coexists with IgG at the air-water interface when the surface layer is built from a mixed IgG-HPβCD-solution. Incorporation of HPβCD in a preformed IgG-surface-layer does not occur. The results confirm surface displacement as the stabilization mechanism of polysorbate 80, but refute the frequently held opinion, that HPβCD stabilizes proteins against aggregation at the air-water interface in a manner comparable to non-ionic surfactants.

Importance of the dynamics of adsorption and of a transient interfacial stress on the formation of aggregates of IgG antibodies

It is common knowledge that aggregation of proteins may occur in aqueous solutions under mechanical stress (shaking or high shear), even in solutions that are stable at rest. Addition of surfactants is a practical generic means to prevent this stress-induced aggregation (e.g. in formulations of therapeutic proteins), which suggests that interfaces contribute to destabilization. We studied here the role of interfacial stress by applying brief mechanical impacts on the air–water interface, in the presence or absence of surfactants, in solutions of immunoglobulin G (IgG), a class of proteins of high importance to the developments of new therapeutics. A variety of surfactants was tested including the neutral ones Tween80, C10–C14 fos-cholines, alkylaminoxide, surfactin, and two ionic ones, TTAB and lauroylsarcosine sodium salt. We determined the presence of aggregates in solution by light scattering. Irrespective of the type of antibody, either human polyclonal or a monoclonal one, we show that the amount of aggregated IgG increases in proportion to the number of impacts on the interface. In the absence of stress, we recorded images of oblate aggregates of IgG (ca. 12 nm height and 200–1200 nm diameter) present at the air–water interface (fluorescence microscopy using anti-Fab or anti-Fc markers, and AFM scans after transfer on freshly cleaved mica). Our results evidence that aggregates are formed at the air–water interface, and are brought in solution by transient stresses applied on the water surface. Rupture of interfacial films is an important source of aggregates in solution. Finally, the role of surface dynamics in the protection brought by surfactants is discussed based on the comparison of protective efficiencies with dynamic surface tension properties (measured by the maximum bubble pressure method). Our work indicates that better protection is conferred by surfactants showing the faster interfacial dynamics, which corresponds also to conditions of faster lowering of the interfacial energy at a short time scale.

SURFACE TENSION, VISCOSITY, AND THERMAL CONDUCTIVITY OF NANOLUBRICANTS AND VAPOR PRESSURE OF REFRIGERANT/NANOLUBRICANT MIXTURES

The results of thermophysical property and vapor-liquid equilibria studies for the systems mineral oil ISO 9 + MoS 2 (70 nm) and Cu (50 nm) nanoparticles, and R600a + nanolubricant are presented. Series of measurements: surface tension (maximum bubble pressure method), thermal conductivity (steady-state hot-wire method), viscosity (capillary tube method), and saturated vapor pressure (static method) were carried out. The size and the concentration of nanoparticles in the lubricant were determined by dynamic light scattering (laser correlation spectroscopy). Experimental data demonstrate some positive effect of nanoparticles doping on the refrigerant properties such as the decreasing of nanolubricant surface tension, thermal conductivity growth, and the shift of vapor pressure curve in refrigerant/lubricant blends. Thus, the use of nanorefrigerants shows clearly the energy efficiency enhance for the vapor compression refrigerating systems.

Modifications of the SURDAT database of the physicochemical properties of metals and alloys

Experimental studies of the surface tension and the density were carried out by means of the maximum bubble pressure method and the dilatometric technique and next, they were compiled with the results of over 12 years of research of the liquid pure components, binary and multicomponent alloys, with the aim to create the SURDAT database of the Pb-free soldering materials. In the last years, a modification of SURDAT has been conducted. The new version, beside the earlier data of the physical properties, also contains such data as: the viscosity data, selected data of the mechanical and electrical properties, the DTA data and the meniscographic study results (contact angle, wetting time, wetting force and interfacial tension). Additionally, the data base of the heat properties, worked out at NIST (National Institute of Standard and Technology from Boulder in Colorado) has been implemented.