Experimental Study of Compressed Air Foam System and Its Foam Rheology

The paper described a newly developed high performance compressed air foam system(CAFS). The effective system generates uniform foam w ith greater momentum by injecting compressed air into flowing foam solution. Foa m generated by this system presented superior viscous and wetting properties to water.A pendulum system was designed to measure yield stress of foam. The results pro ved the existence of yield stress of foam. And the increasing tendency of yield stress with gas fraction and bubble size has also been found out.

Enhanced oil recovery by nonionic surfactants considering micellization, surface, and foaming properties

Surfactants for enhanced oil recovery are important to study due to their special characteristics like foam generation,lowering interfacial tension between oleic and aqueous phases,and wettability alteration of reservoir rock surfaces.Foam is a good mobility control agent in enhanced oil recovery for improving the mobility ratio.In the present work,the foaming behavior of three nonionic ethoxylated surfactants,namely Tergitol 15-S-7,Tergitol 15-S-9,and Tergitol 15-S-12,was studied experimentally.Among the surfactants,Tergitol 15-S-12 shows the highest foamability.The effect of Na Cl concentration and synthetic seawater on foaming behavior of the surfactants was investigated by the test-tube shaking method.The critical micelle concentrations of aqueous solutions of the different nonionic surfactants were measured at 300 K.It was found that the critical micelle concentrations of all surfactants also increased with increasing ethylene oxide number.Dynamic light scattering experiments were performed to investigate the micelle sizes of the surfactants at their respective critical micelle concentrations.Core flooding experiments were carried out in sand packs using the surfactant solutions.It was found tha t22% additional oil was recovered in the case of all the surfactants over secondary water flooding.Tergitol 15-S-12exhibited the maximum additional oil recovery which is more than 26%after water injection.

Improvement of Foaming and Emulsifying Properties of Gluten by Conjugation with Fructose through Maillard Reaction

Gluten has poor emulsifying and foaming ability due to its amino acid composition. In this study, Maillard reaction was used to improve the emulsifying and foaming properties of gluten. The processing conditions for the preparation of gluten-fructose conjugates were optimized by using Box-Behnken model to achieve optimum foaming and emulsifying activity, respectively.The results showed that glycated gluten exhibited enhanced emulsifying activity compared to native control. The processing conditions for the preparation of gluten-fructose conjugates with optimum emulsifying activity were as follows: the temperature was 48℃, reaction time was 72 h, and maltose/gluten(W/W) ratio was 125%. Under such condition, the average emulsifying activity was 66.54%, being improved by about 2.5 times compared with that of native control. The Foaming properties of gluten also increased significantly by glycation modification. The optimum conditions of response were as below: the temperature was 48℃, reaction time was 66 h, and maltose/gluten ratio(W/W) was 110%. Under such condition, the average foaming property was 158.57%, and it was three folds higher than that of the control.

Effects of sphere size on the microstructure and mechanical properties of ductile iron–steel hollow sphere syntactic foams

The effects of sphere size on the microstructural and mechanical properties of ductile iron–steel hollow sphere（DI–SHS） syntactic foams were investigated in this study. The SHSs were manufactured by fluidized-bed coating via the Fe-based commercial powder–binder suspension onto expanded polystyrene spheres（EPSs）. Afterwards, the DI–SHS syntactic foams were produced via a sand-mold casting process. The microstructures of specimens were investigated by optical microscopy, scanning electron microscopy（SEM）, and energy-dispersive X-ray spectroscopy（EDS）. The microscopic evaluations of specimens reveal distinct regions composed of the DI matrix, SHS shells, and compatible interface. As a result, the microstructures and graphite morphologies of the DI matrix depend on sphere size. When the sphere size decreases, the area fractions of cementite and graphite phases are observed to increase and decrease, respectively. Compression tests were subsequently conducted at ambient temperature on the DI–SHS syntactic foams. The results reveal that the compression behavior of the syntactic foams is enhanced with increasing sphere size. Furthermore, the compressed specimens demonstrate that microcracks start and grow from the interface region.

Microstructure and Properties of Cement Foams Prepared by Magnesium Oxychloride Cement

Microstructural features including pore size distribution, cell walls and phase compositions of magnesium oxychloride cement foams（MOCF） with various MgO powders and water mixture ratios were studied. Their infl uences on compressive strength, water absorption and resistance of MOCF were also discussed in detail. The experimental results indicated that moderate and slight excess MgO powders（MgO/MgCl2 molar ratios from 5.1 to 7） were beneficial to the formation of excellent microstructure of MOCF, but increasing water contents（H2O/MgO mass ratios from 0.9 to 1.29） might result in opposite conclusions. The microstructure of MOCF produced with moderate and slight excess MgO powders could enhance the compressive strength, while serious excess MgO powders addition（MgO/MgCl2 molar ratios = 9） would destroy the cell wall structures, and therefore decrease the strength of the system. Although MOCF produced with excess MgO powders could decrease the water absorption, its softening coefficient was lower than that of the material produced with moderate MgO powders. This might be due to the instability of phase 5, the volume expansion and cracking of cell walls as immersed the sample into water.

Mathematical modeling for dynamic stability of sandwich beam with variable mechanical properties of core

The paper is devoted to mathematical modelling of static and dynamic stability of a simply supported three-layered beam with a metal foam core. Mechanical properties of the core vary along the vertical direction. The field of displacements is for- mulated using the classical broken line hypothesis and the proposed nonlinear hypothesis that generalizes the classical one. Using both hypotheses, the strains are determined as well as the stresses of each layer. The kinetic energy, the elastic strain energy, and the work of load are also determined. The system of equations of motion is derived using Hamilton＇s principle. Finally, the system of three equations is reduced to one equation of motion, in particular, the Mathieu equation. The Bubnov-Galerkin method is used to solve the system of equations of motion, and the Runge-Kutta method is used to solve the second-order differential equation. Numerical calculations are done for the chosen family of beams. The critical loads, unstable regions, angular frequencies of the beam, and the static and dynamic equilibrium paths are calculated analytically and verified numerically. The results of this study are presented in the forms of figures and tables.

Study on the Performance of Sodium Methyl Cocoyl Taurate and Its Application in the Shampoo

The effects of pH and water hardness on the foaming properties of sodium methyl cocoyl taurate and its performance in combination with zwitterionic surfactants were investigated.The irritation of sodium methyl cocoyl taurate and its application in a shampoo formula were also studied.According to the result of experiment,sodium methyl cocoyl taurate had a wide pH stability range and good resistance to hard water,and it showed good synergistic thickening effect with betaine surfactants,especially when mixed with acyl hydroxysulfo betaine;The skin cholesterol dissolution test and red blood cell hemolysis test showed that its irritation was very low.Sodium methyl cocoyl taurate was applied to the transparent shampoo formula,and the sulfate-free transparent shampoo thus prepared had good stability and low eye irritation.It was both mild and non-irritating to skin.

The Application of Modified Oil Ethoxylates in Laundry Beads Formulation

The flow ability,foam,and detergency performance of SOE-N-60 are introduced,the advantages of its application in the formulation of laundry beads are analyzed.Then,the formulation of laundry beads based on SOE-N-60 was developed.The results showed that SOE-N-60 has low foaming performance and excellent flow ability at low temperature,and it can maintain good liquidity of the mixed system,the laundry beads formulation has low foaming performance and its detergency meets the industry standards.

Manipulation of polymer foam structure based on CO_2-induced changes in polymer fundamental properties

Foaming of polymers with CO2 has attracted increasing attention in polymer processing studies. Some of the fundamental properties of polymer/CO2 systems is discussed in this short review, including solubility and diffusivity of CO2 in the polymer, polymer crystallization, interfacial tension between the polymer and the gas, and rheology of the CO2/polymers melt. These properties understandably affect the foaming process, and the structures of the foam products. Meanwhile, these properties can be changed via manipulation of CO2 in polymer. The proposed idea is to manipulate the foaming process and the foam structure by CO2-induced changes in these properties. Two cases from the authors＇ laboratory are presented for elucidating how to use the changes to manipulate the foaming process.