China
Africa
Explore chapters and articles related to this topic
Interfacial charge and basic electrical double layer (EDL)
Published in K.S. Birdi, Introduction to Electrical Interfacial Phenomena, 2010
The thickness of the soap film is sum of soap molecule (nm) + water phase (μm) + soap (nm). This varies from micrometer to nm (Birdi, 2009). A soap bubble is a structure of a double layer of soap molecules with water in between (Figure 2.6).
A review of thermodynamic concepts
Published in Ronald L. Fournier, Basic Transport Phenomena in Biomedical Engineering, 2017
In order to develop some useful relationships, let us first consider a soap bubble. A soap bubble consists of a very thin spherical film of liquid. The film is relatively thick on a molecular level, so the innermost portion of the film acts like the bulk liquid. This film has two surfaces that are exposed to the outside atmosphere and the air trapped within the soap bubble. According to Equation 2.181, at constant T and P, the soap bubble can decrease its free energy by decreasing its surface area. Hence, the bubble will decrease in size, placing more of the liquid film molecules in the innermost portion of the film. However, as the bubble shrinks in size, the internal pressure (PB) will increase until a point is reached where the soap bubble can shrink no further. At this point, the net force due to the pressure difference across the bubble film balances the forces in the surface of the bubble trying to shrink the bubble. An equilibrium state then occurs, and we can write that γdAS=PB−PAASdr The left-hand side of the Equation 2.183 represents the work effect needed to expand or contract the bubble by an amount equal to dAS. The right-hand side represents the net force acting on the surface AS, and this force multiplied by the displacement of the interface, dr, is the work needed to change the area of the bubble by an amount, dAS. At equilibrium, Equation 2.183 must be satisfied for any fluctuation in dAS.
Ultrathin films of functionalised single-walled carbon nanotubes: a potential bio-sensing platform
Published in Liquid Crystals, 2020
Monika Poonia, V. Manjuladevi, R. K. Gupta
Thermotropic liquid crystals shows temperature-dependent mesophases whereas the phases of a lyotropic system are dependent on concentration, pressure, ion contents and temperature. There are plethora of examples of lyotropic liquid crystals in nature, e.g. cell membrane, vesicles and soap bubbles [1]. The phases and hence the physicochemical properties of thermotropic and lyotropic liquid crystals can be altered by incorporation of nanomaterials of different shapes and aspect ratios into the liquid crystal matrix [2]. Such incorporation of nanomaterials may induce novel functionalities to the LC-nanocomposites that can be utilised for non-display applications, e.g. sensing, photovoltaics and smart windows. Sensing of a volatile organic compound viz. toluene was reported by observing a phase transition from cholesteric to blue phase due to the presence of vapour of toluene [3]. There are few reports wherein cholesteric phase of liquid crystal was employed as sensing element for bio-sensing application [4,5]. A review article by Lee and Lee discusses the potential of thermotropic liquid crystal for bio-sensing application [6]. The field is in nascent stage, and therefore, non-conventional approaches should be explored in this direction.
Consequences of aircraft operating conditions at military airbases: degradation of ordinary mortar and resistance mechanism of acrylic and silica fume modified cement mortar
Published in Road Materials and Pavement Design, 2022
Sukanta Kumer Shill, Safat Al-Deen, Mahmud Ashraf, M. G. Rashed, Wayne Hutchison
AE commonly contains an abundance of submicron-sized spheres, each of which comprises an ample amount of acrylic polymer chains. The spheres usually coalesce around crystalline minerals, such as , and aggregates when added to the cement mixture. Additionally, bonds of carboxylate groups in acrylic polymer significantly react with and ions during the initial stage of hydration (Hazimmah & Muthusamy, 2016; Larbi and Bijen, 1990). Among all minerals, is very reactive, contains a higher volume of , and contributes early strength of cement mortar. During the hydration of , they released a significant amount of , which were initially trapped by acrylic polymer chain, and reacted with bonds of carboxylate groups, resulted in calcium carboxylate, which are calcium salts of long-chain fatty acids, resulted in soap bubbles in the mortar. Plenty of soap bubbles were noticed in the fresh mortar when AE was added. However, when soaps came in contact again with hard water, they released ions and contributed to form and ettringite in the mortar.
Parametric studies on hydrocarbon fireball using large eddy simulations
Published in Combustion Theory and Modelling, 2019
Ashish V. Shelke, Bhuvaneshwar Gera, Naresh K. Maheshwari, Ram K. Singh
J. Kuchta [3] studied the fireball size under impact conditions of tanks filled with fuels JP-4 and JP-5. Fay and Lewis [4] studied the burning of unconfined fuel vapour clouds of volume 200 cm3. They performed small-scale experiments with methane, ethane and propane gases at room temperature. Fay and Lewis [4] used spherical gas samples inside soap bubbles of volumes 20 to 190 cm3 for fireball experiments. Hasegawa and Sato [5] used hermetically sealed, spherical glass vessels. Each vessel was filled with n-pentane assembled with an electric heater and a thermocouple for measuring the temperature of the liquid. The amount of pentane used was in the range of 0.3 to 6.2 kg. Hardee et al. [6] investigated pure methane and premixed methane-air fireball reactions. They used balloons filled with 0.1 to 10 kg pure methane or stoichiometric air-methane mixtures. Lihou and Maund [7] used soap bubbles filled with flammable gas to form fireballs. They carried out two series of experiments. The first series involved butane-filled bubbles whose masses ranged from 1.5 × 10−3 to 6 × 10−3 kg. The second series was performed with methane and butane in volumes ranging from 100 to 800 cm3 (for methane of mass range from 7 × 10−5 to 6 × 10−4 kg and for butane it was from 2.4 × 10−4 to 1.9 × 10−3 kg) [7]. J. Schmidli [8] focused on the distribution of mass on rupture of a vessel containing a superheated liquid below its superheat temperature limit. They filled flasks (50 ml and 100 ml capacity) partially with butane or propane. Roper et al. [9] studied the effect of release velocity and geometry on burning times for non-premixed fuel gas clouds using propane and methane.