China
Africa
Explore chapters and articles related to this topic
The Surface Chemistry of Paper: Its Relationship to Printability and Other Paper Technologies
Published in Terrance E. Conners, Sujit Banerjee, Surface Analysis of Paper, 2020
Frank M. Etzler, James J. Conners
The maximum bubble pressure method (see Adamson1) can be used to determine the surface tension of inks. In this method, a bubble of inert gas is made at the orifice of a capillary. Under ideal conditions, the maximum pressure occurs where the radius of the bubble is equal to the outside diameter of the capillary. In practice a correction factor must be applied to the calculation to compensate for the asphericity of the drop. This method can be used to determine the surface tension of fluid inks but cannot be used to determine polar and non-polar contributions to the surface tension. As bubbles may be formed at various rates, the dynamic surface tensions of inks may be measured by this method. Aqueous surfactant solutions require fairly long periods to reach surface equilibrium. This long equilibrium time results from the time required for large surfactant molecules to diffuse from the bulk solution to the newly created surface. Solutions containing only small molecules reach equilibrium quickly. In general, the surface tension declines exponentially from the surface tension of water to the value of the equilibrium surface tension over time. Dilute surfactant solutions may take as much as a few hours to reach equilibrium. Times of the order of milliseconds have been observed in inks.
Basic Formulations and Components of Ramjet Propellants
Published in WeiQiang Pang, Luigi T. De Luca, XueZhong Fan, Oleg G. Glotov, FengQi Zhao, Boron-Based Fuel-Rich Propellant, 2019
WeiQiang Pang, Luigi T. De Luca, XueZhong Fan, Oleg G. Glotov, FengQi Zhao
Solid propellant is a kind of macromolecule energetic material filled with a great amount of solid particles. Surface/interfacial properties are the characteristics of the surface/interface between its components (solid–solid, solid–fluid, and fluid–fluid). It influences many aspects of solid propellants, including rheological properties, structural integrity, and mechanical properties.10 According to some processes and combustion properties, amorphous boron powder needs to go through surface treatments in the production process of boron-based fuel-rich propellants, including purification, inactivation, coating, agglomeration, and so on.3–7 Different treatments play an important role in the properties of the surface/interface between the boron powder produced in different ways and the binder system as well as solid fillers. As the surface properties of boron powder changes, its other properties change as well, such as surface tension and surface free energy. Thus, the tension of the interface with binders and the adhesion work change as well. Therefore, the surface/interfacial phenomenon is the key area in the study of material surface/interface field.8,9 Currently, there are many methods to study surface/interfacial properties, such as capillary rise method, maximum bubble pressure method, drop weight method, drop volume method, contact angle method, thin capillary osmosis, etc., and contact angle method has become one of the standard methods to characterize solid surface/interface because of its convenience and maturity.11–13
Interfaces and the Concept of Surface Tension
Published in Andrew Terhemen Tyowua, Liquid Marbles, 2018
The maximum bubble pressure method has been used to measure interfacial tension for many years and has now been modified to measure even dynamic (i.e. non-equilibrated) interfacial tension. In the maximum bubble pressure method (Figure 1.5), the maximum pressure Pmax needed to force a gas bubble out of a capillary tube of radius Rc into a liquid is measured. The Pmax is equal to the sum of the capillary pressure ΔP caused by the interfacial tension and the hydrostatic pressure (ρgh) caused by the liquid column above the orifice of the capillary as shown in Equation (1.19).
Droplet impingement method to measure the surface tension of molten zirconium oxide
Published in Journal of Nuclear Science and Technology, 2020
Toshiki Kondo, Hiroaki Muta, Yuji Ohishi
The surface tension is usually measured using methods such as the sessile drop method [7], maximum bubble pressure method [8], and pendant drop method [9]. Although these methods can facilitate the determination of the surface tension, the measurement cannot be performed at a high temperature because the molten oxides melt or react with the component of the apparatus, thereby affecting the result of the measurement [10]. Recently, contactless methods have been improved, and some research groups have reported on the surface tension of molten oxides by using the aerodynamic levitation system (ADL) [11,12]. However, conventional ADL methods involve considerably long time (approximately a few minutes) to measure the surface tension because five resonant frequencies must be determined to evaluate the surface tension accurately [13]. The surface tension evaluated using only one resonant frequency is said to be underestimated by approximately 20% [12]. This aspect indicates that the ADL method is not suitable for measuring the surface tension of materials with high vapor pressure such as ZrO2 [14].
Heat Transfer in Laminar Graetz and Taylor Flows Incorporating Nanoparticles
Published in Heat Transfer Engineering, 2022
Khalifa Alrbee, Yuri Muzychka, Xili Duan
Another study was performed by Zhou et al. [47] to show effect of adding nanoparticles on surface tension of water. The maximum bubble pressure method was employed to measure the surface tension of Al2O3-H2O nanofluids. They used nanoparticle sizes 10 nm and 20 nm with four different concentrations (1%, 1.5%, 2% and 1.5%), and 50 nm and 100 nm with the concentration of 2.5%. The obtained results showed that the surface tension of nanofluids increases with the increase of nanoparticle concentration. Furthermore, their results revealed that the excess concentration over the critical value can reduce the surface tension of nanofluids.
Interfacial molecular array behaviors of mixed surfactant systems based on sodium laurylglutamate and the effect on the foam properties
Published in Journal of Dispersion Science and Technology, 2018
Chenyang Xue, Hui Zhao, Qiaozhi Wang, Kai Zhang, Ying Li
The equilibrium surface tension of surfactant systems was performed on a K100 apparatus (KRÜSS GmbH, Hamburg) with the Wilhelmy plate method. The surface tension of Milli-Q water (18.25 MΩ · cm) was measured in order to ensure the accuracy of the instrument. The metal plate need to be burned using alcohol to remove the impurities of the surface. The dynamic surface tension measurements were performed with the maximum bubble pressure method on the SITA pro line t15 tensiometer (Germany). The bubble was generated by a PEEK capillary about 10 mm. The device was calibrated and cleaned using Milli-Q water.