Determination Of Surface Tension Research Articles

Water activity and surface tension of aqueous ammonium sulfate and D-glucose aerosol nanoparticles

Abstract. Water activity (aw) and interfacial energy or surface tension (σ) are key thermodynamic parameters to describe the hygroscopic growth of atmospheric aerosol particles and their ability to serve as cloud condensation nuclei (CCN), thus influencing the hydrological cycle and climate. Due to size effects and complex mixing states, however, these parameters are not well constrained for nanoparticles composed of organic and inorganic compounds in aqueous solution. In this study, we determined aw and σ by differential Köhler analysis (DKA) of hygroscopic growth measurement data for aerosol particles smaller than 100 nm composed of aqueous ammonium sulfate (AS), D-glucose (Gl), and their mixtures. High-precision measurements of hygroscopic growth were performed at relative humidities (denoted RH) ranging from 2.0 % to 99.6 % with a high-humidity tandem differential mobility analyzer (HHTDMA) in three complementary modes of operation: hydration, dehydration, and restructuring. The restructuring mode (hydration followed by dehydration) enabled the transformation of initially irregular particles into compact globules and the determination of mass equivalent diameters. The HHTDMA-derived growth factors complemented by DKA allows for determination of water activity and surface tension from dilute to highly supersaturated aqueous solutions that are not accessible with other methods. Thus, for mixed AS / Gl nanoparticles with mass ratios of 4:1 and 1:1, the upper limit of solute mass fraction (Xs) was 0.92 and 0.98, respectively. For pure AS and Gl, the DKA-derived aw is in good agreement with electrodynamic balance and bulk measurement data. For AS particles, our aw data also agree well with the Extended Aerosol Inorganics Model (E-AIM III) over the entire concentration range. In contrast, the UNIFAC model as a part of AIOMFAC (Zuend et al., 2011) was found to overestimate aw in aqueous Gl particles, which can be attributed to unaccounted intermolecular interactions. For mixed AS and Gl nanoparticles, we observed a non-monotonic concentration dependence of the surface tension that does not follow the predictions by modeling approaches constructed for mixed inorganic/organic systems. Thus, AS / Gl particles with a 1:1 mass ratio exhibited a strong decrease of σ with increasing solute mass fraction, a minimum value of 56.5 mN m−1 at Xs≈0.5, and a reverse trend of increasing σ at higher concentrations. We suggest that D-glucose molecules surrounded by ammonium sulfate ions tend to associate, forming non-polar aggregates, which lowers the surface tension at the air–droplet interface. We analyzed the uncertainty in the DKA-derived water activity and surface tension, related to the instrumental errors as well as to the morphology of the nanoparticles and their phase state. Our studies have shown that under optimal modes of operation of HHTDMA for moderate aqueous concentrations, the uncertainty in aw and σ does not exceed 0.2 %–0.4 % and 3 %–4 %, respectively, but it increases by an order of magnitude in the case of highly concentrated nanodroplet solutions.

Viscosity and surface tension of the Zr56.5Ti13.3Ni13.6Cu9.6S7 bulk metallic glass-forming liquid

The viscosity of the Zr56.5Ti13.3Ni13.6Cu9.6S7 bulk glass forming alloy was measured in equilibrium liquid at low and high temperatures. Low temperature measurements were conducted in the vicinity of the glass transition using a thermomechanical analyzer, covering a viscosity range between 109 and 1014 Pa s. The high-temperature experiments were carried out by electromagnetic levitation of a spherical droplet in microgravity during a parabolic flight campaign (TEMPUS), ranging in viscosity from 50 to 800 mPa s. The viscosities were individually modeled using the Vogel–Fulcher–Tammann equation to obtain the fragility parameter D*, which displays a strong liquid behavior of 25.8 and 19.6 for the low and high temperature region, respectively. The Mauro–Yue–Ellison–Gupta–Allan viscosity model was additionally applied, revealing an even more accurate description across the whole temperature range. Next to viscosity, TEMPUS measurements allow the determination of surface tension. With a value of 0.9 N m−1, it is significantly lower than that of other Zr-based metallic glasses without the element sulfur.

Exploration of surface tension measurement methods for pharmaceutical excipients

Surface tension is a crucial functional indicator for various classes of pharmaceutical excipients, as highlighted in both the Pharmacopoeia of the People’s Republic of China (ChP) < 9601 Guidelines for Functionality-related Characteristics of Pharmaceutical Excipients > and the United States Pharmacopoeia (USP) < 1059 Excipient Performance >. However, there are few systematic studies on surface tension measurement of pharmaceutical excipients, resulting in a lack of stable parameter support in practical applications. In this study, we aim to fill this gap by exploring three different methods for measuring surface tension. These methods were carefully developed taking into account the actual measurement process and statistical theory, thus ensuring their applicability and reliability. Through comparative analyses, we have identified the most suitable measurement methods for different classes of pharmaceutical excipients. In addition, this paper describes the surface adsorption behavior of various excipients. Therefore, this study provides valuable guidance for the determination of surface tension and the study of surface adsorption behavior, which lays the foundation for further comprehensive research in the field of surface tension of pharmaceutical excipients and the improvement of general pharmacopoeia specification.

Surface activity and micellization of streptomycin sulfate and diphenhydramine hydrochloride in the presence of alkali and alkaline earth metal chlorides

ABSTRACT The study investigated the surface tension of the surface-active drugs streptomycin sulfate and diphenhydramine hydrochloride using three uni-univalent and three bi-univalent electrolytes: NaCl, KCl, and RbCl (0.01 mol.kg−1), and MgCl2, CaCl2, and SrCl2 (0.002 mol.kg−1) over a temperature range of 298.15 to 313.15 K. Surface tension determination has proven instrumental in examining the micellization and surface-active properties of these drugs in the presence of specific electrolytes. The surface tension values of these drugs exhibit a decrease in magnitude with increasing drug concentration, particularly noticeable in streptomycin sulfate. This phenomenon can be elucidated by considering the delicate balance between hydrophobic and hydrophilic forces within the system. Additionally, the impact of the nature of metal halides and temperature on surface tension magnitude has been scrutinised, with interpretations focused on alterations in size. From surface tension values, the interfacial parameters, such as Γ max , A min , and π CMC were examined. The results indicate a strong affinity between drug-electrolyte molecules that reduces the surface tension values. The CMC relations govern the hydrophobic and hydrophilic interactions in the ternary system of water-drug-electrolyte. The thermodynamics of micellization explains the work done for micellization and illuminates the surface and bulk properties of drugs.

Liposomes as a carrier for 4–hydroxycoumarin: characterisation, stability and antioxidant potential

&amp;lt;p&amp;gt;The aims of the present research were to develop and characterize 4-hydroxycoumarin-loaded liposomes &amp;lt;em&amp;gt;via &amp;lt;/em&amp;gt;the determination of encapsulation efficiency, antioxidant capacity, vesicle size, polydispersity index (PDI), zeta potential, conductivity, mobility, density, surface tension, viscosity, and 60-day storage stability. The encapsulation efficiency of 4-hydroxycoumarin in liposomal particles was 96.7 &amp;amp;plusmn; 1.2%. The ABTS and DPPH radical scavenging capacity of the prepared liposomes was 89.76 &amp;amp;plusmn; 0.56% and 93.18 &amp;amp;plusmn; 0.23%, respectively, whereas cupric ion-reducing antioxidant capacity amounted to 0.367 &amp;amp;plusmn; 0.003 mmol Trolox equivalent (TE)/L. The density of liposomes with 4-hydroxycoumarin was 1.007 &amp;amp;plusmn; 0.002 g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, surface tension was 22.7 &amp;amp;plusmn; 0.2 mN/m, and viscosity was 14.3 &amp;amp;plusmn; 0.2 mPa&amp;amp;middot;s. Vesicle size and PDI of 4-hydroxycoumarin-loaded liposomes were changed from 1286.3 &amp;amp;plusmn; 73.8 nm to 2077.3 &amp;amp;plusmn; 63.2 nm and from 0.409 &amp;amp;plusmn; 0.050 to 0.676 &amp;amp;plusmn; 0.064, respectively, during the 60-day stability study. The zeta potential of the obtained liposomes was changed from -16.73 &amp;amp;plusmn; 0.47 mV to -10.31 &amp;amp;plusmn; 0.42 mV, while mobility varied from -1.311 &amp;amp;plusmn; 0.036 &amp;amp;micro;mcm/Vs to -0.806 &amp;amp;plusmn; 0.031 &amp;amp;micro;mcm/Vs. The conductivity did not change during 60 days and amounted to approximately 0.020 mS/cm. Overall, due to the high encapsulation efficiency and antioxidant capacity, the obtained results qualify liposomes to be used as 4-hydroxycoumarin carriers for future examination of its biological activities and potential application in medicine and pharmaceutical products. However, future experiments should include the optimization of the liposomal composition with the aim of improving 4-hydroxycoumarin-loaded liposome stability.&amp;lt;/p&amp;gt;

The Influence of Pseudoplastic Flow Behavior on the Slot Die Process in Solid Electrolyte Production

Solid-state batteries (ASSB) are the next generation of batteries for energy storage. An ion-conducting solid replaces the liquid electrolyte. The trend is toward thin, homogeneous solid electrolytes (SE) that replace the liquid electrolyte and separator. At the same time, the use of a lithium metal anode and the reduction of the layer thickness enable higher energy and power densities. SEs should have a high mechanical strength with a certain flexibility. In addition, electrochemical and chemical properties such as good electrical isolator and good ion conductor, as well as low flammability, are essential. This requirement profile for SEs increases the demand for suitable materials and their processing methods.A promising candidate for the production of SE is the slot die process. This process is mainly controlled by three process parameters, i.e. coatings speed, dispense rate and coating gap. Compared to other production methods, this makes it easy to set parameters for targeted coating thicknesses. The process is already used in many production steps, e.g. for electrodes in the conventional lithium ion battery production. This provides a good opportunity to use and adapt this knowledge for SE production.In general, for coating solutions, structurally viscous fluids have well suited properties. The change in flow properties during shear stress can be used to achieve a certain stability between the coating tool and the substrate to avoid defects during coating. It also ensures easy handling of the system after processing and the shape stability of the resulting coatings.Therefore, a promising candidate as base material for SE production is Poly(ethylene oxide) (PEO). In addition to the shear thinning (or pseudoplastic) flow behavior, it also offers many advantages, such as its good availability on the global market, high solubility in solvents such as acetonitrile, and the capability to dissolve conductive salts like the alkali salt Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).The aim of this work is to investigate the influence of the pseudoplastic flow behavior during and after the coating process by varying the molecular weight (Mw) of PEO. Therefore, the coating window is evaluated as a function of material properties MW and solution concentration. From viscosity and surface tension determination, an increase in MW leading to a stronger pseudoplastic flow behavior can be observed. For the coating process, a DoE employing a constant set of the process parameters dispense rate, coating gap and coating speed is used. The produced layers are evaluated based on their coating quality, dry layer thickness and ionic conductivity. For each solution, the obtained coating window is compared to a theoretical film break-up model.This work shows successful production of SE with an ionic conductivity of 10-6 S/cm using different MW. Further, the experimental results are comparable to the theoretical models. Moreover, the experiments show both, a dependency of MW and PEO concentrations. Within one MW, stable coating window becomes smaller with increasing concentration. Similar behavior is observed at a constant concentration with different MW. Due to the change in flow properties, the stable coating window becomes smaller with increasing MW. As a result of these correlations, the produced dry layer thickness varies depending on the use of MW and the associated PEO concentration.

Wettability of Quartz by Ethanol, Rhamnolipid and Triton X-165 Aqueous Solutions with Regard to Its Surface Tension

The wettability of quartz by different liquids and solutions plays a very important role in practical applications. Hence, the wetting behaviour of ethanol (ET), rhamnolipid (RL) and Triton X-165 (TX165) aqueous solutions with regard to the quartz surface tension was investigated. The investigations were based on the contact angle measurements of water (W), formamide (F) and diiodomethane (D) as well as ET, RL and TX165 solutions on the quartz surface. The obtained results of the contact angle for W, F and D were used for the determination of quartz surface tension as well as its components and parameters using different approaches, whereas the results obtained for the aqueous solution of ET, RL and TX165 were considered with regard to their adsorption at the quartz–air, quartz–solution and solution–air interfaces as well as the solution interactions across the quartz–solution interface. The considerations of the relations between the contact angle and adsorption of solution components at different interfaces were based on the components and parameters of the quartz surface tension. They allow us to, among other things, establish the mechanism of the adsorption of individual components of the solution at the interfaces and standard Gibbs surface free energy of this adsorption.

The shape of things to come: Axisymmetric drop shape analysis using deep learning

HypothesisIn the traditional approach to Axisymmetric Drop Shape Analysis (ADSA), the determination of surface tension or interfacial tension is constrained by computational speed and image quality. By implementing a machine learning-based approach, particularly using a convolutional neural network (CNN), it is posited that analysis of pendant drop images can be both faster and more accurate. ExperimentsA CNN model was trained and used to predict the surface tension of drop images. The performance of our CNN model was compared to the traditional ADSA, i.e. direct numerical integration, in terms of precision, computational speed, and robustness in dealing with images of varying quality. Additionally, the ability of the CNN model to predict other drop properties such as Volume and Surface Area was evaluated. FindingsOur CNN demonstrated a significant enhancement in experimental fit precision, predicting surface tension with an accuracy of (+/-) 1.22×10−1 mN/m and at a speed of 1.50 ms−1, outpacing the traditional method by more than 5×103 times. The model maintained an average surface tension error of 2.42×10−1 mN/m even for experimental images with challenges such as misalignment and poor focus. The CNN model also demonstrated showcased a high degree of accuracy in determining other drop properties.

Theoretical analysis of the spray characteristics of ternary blends of diesel, biodiesel, and long-chain alcohols inside a combustion chamber

The diesel and alcohol blends are potential alternatives to biogenic fuels to reduce biodiesel consumption, which might help reduce toxic emissions. Due to the high-quality requirements for engines, the fuel fundaments in the fluid properties and its impact on the macroscopic spray characteristics. Herein, a study proposed the experimental determination of density, viscosity, and surface tension for ternary mixtures of diesel (D) + biodiesel (B) + 1-hexanol (H) and + 1-octanol (O) at 298.15 K. These properties comply with the limits established by the EN 14214 and ASTM D975 standards. Thus, to extend the impact of these results, a theoretical analysis via CFD is carried out in ANSYS FLUENT ® by considering a macroscopic and isothermal system, which involved the independence tests of meshing and turbulence modeling. The numerical results evaluated the spray tip penetration, spray angle, spray morphology, eddy turbulence, and relation of spray volume and surface spray area at the injection pressure of 90 MPa using the Large Eddy Simulation (LES) model. The behavior of the spray tip penetration and spray angle agree with experimental values reported in the literature for diesel fuel. This condition validates our simulations for biodiesel and ternary blends. Therefore, the use of alcohols and biodiesel as new additives to diesel improves the macroscopic spray characteristics, and some ternary mixtures showed similar behavior to conventional diesel: spray tip penetration (70D5B25O, 70D25B5H, and 70D25B5O) and spray angle (70D25B5H, 70D15B15H, 80D5B15O, and 80D15B5). The mixture of 70D25B5H agrees with both spray characteristics; therefore, this mixture could be considered an alternative fuel to conventional diesel. Hence, this analysis presents the essential elements to visualize the macroscopic spray characteristics and the fluid properties. This knowledge serves as a foundation for elucidating the intricate dynamics of spray during combustion processes and the development of complementary studies aimed at optimizing engine performance.

Measurement of surface tension with free-falling oscillating molten metal droplets: a numerical and experimental investigation

AbstractRayleigh’s equation has been widely used to determine surface tension from oscillating droplets. In this study, the use of a drop-on-demand droplet generator is proposed to create free-falling, oscillating, molten metal droplets for this purpose. To examine the applicability of the droplet generator, extensive numerical simulations in three and two-dimensions were performed. The effect of gravity, initial velocity and initial deformation on the frequency and pattern of the droplet oscillation was investigated. The use of this generator enables the creation of thousands of droplets in the course of a single experiment and the droplets have a much shorter exposure time to possible unwanted contaminations, due to a rapid measurement principle. Furthermore, the adjustable nozzle size of the generator provides flexibility in terms of droplet size, which affects the range of validity of Rayleigh’s method. To validate the method, the surface tension of molten copper in an argon atmosphere was determined over a temperature range of 1400–1620 K. The determined linear relation is expressed as σ [mN m−1] = (1307 ± 98) − (0.22 ± 0.015) (T−1356) (T in K).

High-Temperature Measurements on Viscosity and Surface Tension of the Ionic Liquid 1-Ethyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide ([EMIM][NTf2]) up to 473 K

In the present study, the viscosity and surface tension of the commercial low-viscosity ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide ([EMIM][NTf2]) were determined by a combination of surface light scattering (SLS) and the pendant-drop (PD) method between (303 and 473) K. Both methods operating at thermodynamic equilibrium were applied inside the same measurement cell at identical experimental conditions under an argon atmosphere at 0.1 MPa. For SLS measurements performed in the temperature range from (303 to 323) K, the overdamped behavior of the surface fluctuations allowed access to the viscosity with an expanded uncertainty of 2.3 % using the surface tensions determined via the PD method with an uncertainty of 2 % as input quantities. Above 323 K up to 473 K, the oscillatory behavior of the probed surface fluctuations by SLS enabled a simultaneous determination of viscosity and surface tension with average expanded uncertainties of (4 and 3) %, respectively. Multiple repetition measurements by both methods have been conducted at 323 K after experiments at larger temperatures up to 473 K, and the consistency of their results could indicate a sound thermal stability of the IL sample. The mutual agreement of the surface tension results from SLS and the PD method between (353 and 473) K demonstrates that both techniques analyze the very same IL surface. For both properties, the results from this work agree well with the majority of experimental data reported in the literature typically up to 353 K. In summary, the viscosity and surface tension results presented in this study contribute to an improved data landscape for this particular IL and ILs in general at elevated temperatures.

Artificial Intelligence Techniques and Response Surface Methodology for the Optimization of Methyl Ester Sulfonate Synthesis from Used Cooking Oil by Sulfonation.

Herein, the impacts of sulfonation temperature (100-120 °C), sulfonation time (3-5 h), and NaHSO3/methyl ester (ME) molar ratio (1:1-1.5:1 mol/mol) on methyl ester sulfonate (MES) yield were studied. For the first time, MES synthesis via the sulfonation process was modeled using the adaptive neuro-fuzzy inference system (ANFIS), artificial neural network (ANN), and response surface methodology (RSM). Moreover, particle swarm optimization (PSO) and RSM methods were used to improve the independent process variables that affect the sulfonation process. The RSM model (coefficient of determination (R2) = 0.9695, mean square error (MSE) = 2.7094, and average absolute deviation (AAD) = 2.9508%) was the least efficient in accurately predicting MES yield, whereas the ANFIS model (R2 = 0.9886, MSE = 1.0138, and AAD = 0.9058%) was superior to the ANN model (R2 = 0.9750, MSE = 2.6282, and AAD = 1.7184%). The results of process optimization using the developed models revealed that PSO outperformed RSM. The ANFIS model coupled with PSO (ANFIS-PSO) achieved the best combination of sulfonation process factors (96.84 °C temperature, 2.68 h time, and 0.92:1 mol/mol NaHSO3/ME molar ratio) that resulted in the maximum MES yield of 74.82%. Analysis of MES synthesized under optimum conditions using FTIR, 1H NMR, and surface tension determination showed that MES could be prepared from used cooking oil.

Determination of critical surface tension of wetting of textured water-repellent surfaces

The object of study is aluminum textured with a femtosecond laser and modified with silanes to reduce surface energy. The presence of a special texture on the surface, such as protrusions or hairs, and the inherently low surface energy of the material allow maximizing the water repellency properties. The determination of the critical wetting surface tension by the Zisman method has a pronounced wetting transition point, but the coordinates of this point cannot be accurately predicted. In this work, the Zisman method is considered as a tool for comparing the effectiveness of modifiers for femtosecond laser-textured surfaces. In this work, periodic structures were created by laser ablation on the surface of aluminum, the surface was modified to achieve the Cassie state when wetted with water, and the critical surface tension of wetting was determined by the Zisman method. As a result, it is shown that the Zisman method in combination with the data on the water contact angle values is an effective tool for characterizing the quality of surface modification of textured samples. It is shown that for textured aluminum surfaces, the most effective modifier is silane, which maintains the Cassie wetting state, with a contact angle increased from 155 to 160°. Paraffin has been shown to be a less effective modifier with an implicit wetting plateau and a transition in the range of 30 to 40 mN/m. It is shown that the textures that have acquired water repellency in the course of spontaneous hydrophobization are very unstable to the action of liquids with reduced polarity, although they have high values of the water contact angle. In practice, the creation of water-repellent coatings on aluminum is a promising substrate due to their widespread use in the aviation, automotive, and energy industries due to their high mechanical strength, lightness, and stability of properties.

The use of pracaxi oil collector in the selective flotation of xenotime from silicates

Rare earth elements have played a key role in technological advancement, attracting great visibility in the global commodity market. Xenotime, a heavy rare earth resource (YPO4), can be found associated with granitic rocks, as in the Pitinga deposit, located in the Brazilian Amazon region, where the main gangue minerals are quartz, microcline and albite. This research investigates the application of a new collector produced from pracaxi oil, an Amazon oil abundant in Brazil, in the selective flotation between xenotime and its main gangue minerals. The study conducted the synthesis and characterization of the collector, the chemical, mineralogical and surface characterization of minerals, as well as the evaluation of collector adsorption and flotability via microflotation tests, zeta potential measurements, surface tension determination and XRD, WDXRF, ICP-MS, FTIR and XPS analyses. The pracaxi collector was found to be mainly composed of oleic acid (56.2%), linoleic acid (14.1%) and behenic acid (10.6%), in addition to exhibiting a critical micelle concentration (CMC) of approximately 150 mg/L. Microflotation tests indicated that the best condition for selective recovery of xenotime occur at alkaline condition (pH 9.0), presenting selectivity of approximately 90% with collector concentration of 10.0 mg/L. The zeta potential data confirmed a selective adsorption of pracaxi collector onto xenotime, with an increase in the surface charge from −30 mV to −68 mV, whereas no significant changes were detected in the silicates. The FTIR spectra showed the appearance of a band at 1545 cm−1 on the surface of the xenotime after collector adsorption, which indicates, along with the zeta potential data, the chemical nature of the adsorption. The presence of small amounts of iron in the lattice structure of silicate gangues can act as an activator, and therefore, may be responsible for the small flotability of these minerals. The performance of the pracaxi oil collector presented in this study indicates the great potential of this Amazonian oil for application in the selective flotation of xenotime ores found in the region.

Determination of Density and Surface Tension of CaO–SiO2–Al2O3 Molten Slag by Pendant Drop Method

Determination of Density and Surface Tension of CaO–SiO2–Al2O3 Molten Slag by Pendant Drop Method

Experimental Determination and Modeling of Density, Viscosity, and Surface Tension for Sulfolane + Ethyl Acetate and + n-Propyl Acetate

The density, viscosity, and surface tension for the binary mixtures of sulfolane + ethyl acetate and + n-propyl acetate were measured at the atmospheric pressure and temperature ranging from 308.15 to 328.15 K. The linear equation and Andrade model were successfully used to correlate the experimental density and viscosity, respectively. On the basis of the experimental data, the viscosity energy barrier and the surface entropy/enthalpy were further obtained. The calculation of the molecular interaction energy using the Dmol3 module in Materials Studio software shows that the interaction energy in sulfolane + ethyl acetate is slightly greater than one in sulfolane + n-propyl acetate, which is consistent with the experimental observation. In addition, each experimental property of density, viscosity, and surface tension can well be reproduced by the square-well chain fluid with variable range (SWCF-VR) equation of state with one different binary adjustable parameter.

Handling uncertainty in rheological properties of green eggshell nanocomposites by a fuzzy-hybrid modeling approach: a comparative study

Fuzzy regression is an attractive application due to its ability to solve problems in the absence of accurate mathematical models. In this study, rheological properties of a bio-nanocomposite were predicted using fuzzy regression. The aim of study is to introduce the methodology and application of fuzziness in detail for handling uncertainty in the experimental data. In this context, rheological properties of green eggshell bio-nanocomposites are investigated using different operating parameters. Since the determination of surface tension is prone to experimental errors, a novel fuzzy-hybrid model is proposed in addition to a crisp model. Statistical error analysis is conducted to assess the validity of the multivariate models proposed. While both models provided satisfactory results, it is observed that the fuzzy-hybrid model outperforms the crisp model in both accuracy and generality. This study highlights that the proposed models have an impressive potential to be used for modeling experimental studies in nanotechnological manufacturing applications.

Investigation of selected materials stability for future application in development of small fast modular reactors (SFMR)

Currently, there is growing demand for cheap and reliable electricity production. One possible solution could be the construction of small modular fast neutrons nuclear reactors, where the reactor core cooling fluid is a suitable liquid metal. Liquid tin has significant advantages over the other potential candidates but its usage as coolant is challenging for the confining materials ensuring the nuclear safety of the future reactors. Current paper presents an investigation of structural materials stability in liquid tin with measurement of the surface tension, based on “Wilhelmy plate” method. The results are related to stability of spring steel, iron, nickel and copper, used as dipping plates as well as oxygen/liquid tin interactions when melted tin is exposed to air. The reported custom apparatus in our previous studies, was improved and its measuring capability was enhanced in order to demonstrate reliable results at low cost. Theoretical analysis is provided in order to demonstrate the reliability of the presented approach. Main results include: (1) Determination of liquid tin surface tension in case of air oxygen/tin reaction in liquid surface; (2) Investigation of measuring plate degradation and calculation of solution rate constant in case of dipped a plate made by copper; (3) Determination of Butler’s equation parameters in case of surface oxygen/tin interactions.

Modelling the effect of vibrations on the surface tension of a liquid droplet using meshless methods

Application of vibration impacts for purposeful influence on such processes as drop formation, melt bath formation and crystallization of welding bead allows to control heat and mass transfer in liquid, crystallization process and shape of bead in technological processes of welding. Impact of vibration influences on nature of motion of liquid in the drop, which is reflected in the change of value of surface tension coefficient, is considered in the article. The mathematical model of the liquid flow considering surface tension force in formalism of smoothed particles hydrodynamics method is offered. This method allows direct consideration of the vibration effect by introducing additional boundary conditions. Verification of developed mathematical model is conducted in comparison with in-situ experiments, in which dependence of surface tension coefficient value on amplitude of speed of vibration influences was determined. To determine surface tension coefficient two methods were implemented: pending drop method and stalagmometric method. The implemented model satisfactorily describes the effect of decreasing surface tension coefficient for water. A series of numerical experiments for determining the effect of vibration influences on the value of surface tension coefficient for 12X18H10T steel grade was carried out. It was found that at vibration with speed amplitude equal to 2.0 m/s the decrease of surface tension coefficient value by 30 % is observed. Decrease in surface tension coefficient should facilitate the realization of continuous flowing of metal from the wire, which may positively influence the formation of metal during wire surfacing. Thus, the proposed mathematical model can clearly simulate the effect of vibration effects on the value of the surface tension coefficient and will allow the effect of vibration effects in additive manufacturing to be investigated in the future.

Combined Surface Light Scattering and Pendant-Drop Experiments for the Determination of Viscosity and Surface Tension of High-Viscosity Fluids Demonstrated for Ionic Liquids

The present study provides a strategy for the determination of the viscosity and surface tension of high-viscosity fluids in the form of ionic liquids (ILs) at equilibrium conditions by combining surface light scattering (SLS) and the pendant-drop (PD) method within one experimental setup. Through the study of the same sample under identical conditions by both methods inside a closed system, the surface tension determined via the PD method can be directly used to evaluate the dynamics of surface fluctuations of ILs with an overdamped behavior probed by SLS for accessing their viscosity. In connection with the SLS experiments, variations in the applied detection geometries in reflection and transmission direction and in the probed wave vectors down to relatively small values were also addressed. The reliability and self-consistency of SLS and the PD method applied within the same sample cell has been proven by investigating the reference fluids tris(2-ethylhexyl) trimellitate (TOTM) and n-dodecane featuring relatively high and low viscosities. For the two studied model ILs of opaque to non-transparent color, i.e., the hydrophobic 1-methyl-3-octylimidazolium hexafluorophosphate ([OMIM][PF6]) and the hydrophilic 1,3-bis(2-(2-methoxyethoxy)ethyl)imidazolium iodide ([(mPEG2)2Im]I), the combination of PD measurements and SLS experiments in reflection direction performed at ambient pressure between (303 and 373) K allowed access to the viscosity and surface tension with typical relative expanded uncertainties of (4 and 2) %. These results agree well with own viscosity data from capillary viscometry and experimental data in the literature, demonstrating the performance of the novel approach for the contactless in-situ measurement of viscosity and surface tension of fluids with relatively high-viscosity such as ILs.