Effects of head loss, surface tension, viscosity and density ratio on the Kelvin-Helmholtz instability in different types of pipelines

The study of interactions between polyelectrolytes (PE) and surfactants is of great interest for both fundamental and applied research. These mixtures can represent, for example, models of self-assembly and molecular organization in biological systems, but they are also relevant in industrial applications. Amphiphilic block polyelectrolytes represent an interesting class of PE, but their interactions with surfactants have not been extensively explored so far, most studies being restricted to non-associating PE. In this work, interactions between an anionic amphiphilic triblock polyelectrolyte and different types of surfactants bearing respectively negative, positive and no charge, are investigated via surface tension and solution rheology measurements for the first time. It is evidenced that the surfactants have different effects on viscosity and surface tension, depending on their charge type. Micellization of the surfactant is affected by the presence of the polymer in all cases; shear viscosity of polymer solutions decreases in presence of the same charge or nonionic surfactants, while the opposite charge surfactant causes precipitation. This study highlights the importance of the charge type, and the role of the associating hydrophobic block in the PE structure, on the solution behavior of the mixtures. Moreover, a possible interaction model is proposed, based on the obtained data.

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Study on C–S and P–R EOS in pseudo-potential lattice Boltzmann model for two-phase flows

International Journal of Modern Physics C ◽

10.1142/s0129183117501200 ◽

2017 ◽

Vol 28 (09) ◽

pp. 1750120 ◽

Cited By ~ 5

Author(s):

Yong Peng ◽

Yun Fei Mao ◽

Bo Wang ◽

Bo Xie

Keyword(s):

Surface Tension ◽

Lattice Boltzmann ◽

Equations Of State ◽

Density Ratio ◽

Maximum Density ◽

Lattice Boltzmann Model ◽

Two Phase Flows ◽

Two Phase ◽

Spurious Currents ◽

Pseudo Potential

Equations of State (EOS) is crucial in simulating multiphase flows by the pseudo-potential lattice Boltzmann method (LBM). In the present study, the Peng and Robinson (P–R) and Carnahan and Starling (C–S) EOS in the pseudo-potential LBM with Exact Difference Method (EDM) scheme for two-phase flows have been compared. Both of P–R and C–S EOS have been used to study the two-phase separation, surface tension, the maximum two-phase density ratio and spurious currents. The study shows that both of P–R and C–S EOS agree with the analytical solutions although P–R EOS may perform better. The prediction of liquid phase by P–R EOS is more accurate than that of air phase and the contrary is true for C–S EOS. Predictions by both of EOS conform with the Laplace’s law. Besides, adjustment of surface tension is achieved by adjusting [Formula: see text]. The P–R EOS can achieve larger maximum density ratio than C–S EOS under the same [Formula: see text]. Besides, no matter the C–S EOS or the P–R EOS, if [Formula: see text] tends to 0.5, the computation is prone to numerical instability. The maximum spurious current for P–R is larger than that of C–S. The multiple-relaxation-time LBM still can improve obviously the numerical stability and can achieve larger maximum density ratio.

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Micropumping by Electrowetting

10.1115/imece2001/htd-24200 ◽

2001 ◽

Author(s):

Chang-Jin “CJ” Kim

Keyword(s):

Surface Tension ◽

Recent Effort ◽

Different Types ◽

Digital Microfluidic

Abstract This paper introduces the recent effort to use surface tension in MEMS, especially, to use electrowetting for efficient pumping in microfluidics. Importance of surface tension in microscale is explained, and examples of utilizing it to design microdevices are presented. Development of several devices employing different types of electrowetting is explained. Empowered by the efficient pumping by electrowetting microactuation, a programmable digital microfluidic circuit chip is proposed.

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Effect of surfactants on capacitance properties of carbon electrodes

MRS Proceedings ◽

10.1557/opl.2011.1477 ◽

2011 ◽

Vol 1333 ◽

Cited By ~ 1

Author(s):

Krzysztof Fic ◽

Grzegorz Lota ◽

Elzbieta Frackowiak

Keyword(s):

Surface Tension ◽

Alkaline Solution ◽

Surfactant Concentration ◽

Alkaline Solutions ◽

Carbon Electrodes ◽

Current Load ◽

Target Concentration ◽

Electrolyte Additives ◽

Different Types ◽

Triton X

ABSTRACTEffect of surfactants present in alkaline solutions on the capacitance of carbon electrodes has been studied. Different types of surfactants have been selected for this target. Concentration of these electrolyte additives was 0.005 mol L-1. Decreasing the surface tension in the electrode/electrolyte interface allows better penetration of electrolyte into the pores. Detailed analysis of capacitance versus current load, frequency dependence as well as self-discharge, cyclability and behaviour in wider voltage window proved a useful effect of Triton X-100 on capacitor operating in alkaline solution. Influence of surfactant concentration has also been investigated.

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Efficiency Comparison of Fiber Reinforcement in Vibrated аnd Centrifuged Concretes at Different Types of the Applied Heavy Aggregate

Materials Science Forum ◽

10.4028/www.scientific.net/msf.974.288 ◽

2019 ◽

Vol 974 ◽

pp. 288-292

Author(s):

Sergey A. Stelmakh ◽

Anatoliy I. Shuyskiy ◽

Evgeniy M. Shcherban ◽

Albert Yu. Prokopov

Keyword(s):

Steel Fiber ◽

Density Ratio ◽

Fiber Reinforcement ◽

Crushed Stone ◽

Heavy Weight ◽

Different Types ◽

Efficiency Comparison ◽

The Impact

The article considers and evaluates the impact of dispersed reinforcement of heavy concretes manufactured by means of vibration and centrifugation, various types of fibers on their strength-density ratio. The options of applying different types of heavy-weight aggregates for these concretes: crushed stone, limestone and sandstone are considered. The highest strength-density ratio is registered in centrifuged crushed stone fibrous concretes, and all types of centrifuged concretes has the ratio higher than vibrated concretes with the same composition of the studied fibers. The highest growth of the strength-density ratio for the centrifuged crushed stone fibrous concretes as compared with the vibrated ones was identified in case of dispersed reinforcement with steel fiber.

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A Parametric Bayesian Approach in Density Ratio Estimation

10.20944/preprints201903.0025.v1 ◽

2019 ◽

Author(s):

Abdolnasser Sadeghkhani ◽

Yingwei Peng ◽

Devon Lin

Keyword(s):

Loss Function ◽

Bayesian Approach ◽

Risk Function ◽

Density Ratio ◽

Ratio Estimation ◽

Function Estimation ◽

Bayesian Risk ◽

Different Types ◽

Ratio Estimators

This paper considers estimating the ratio of two distributions with different parameters and common supports. We consider a Bayesian approach based on the Log--Huber loss function which is resistant to outliers and useful to find robust M-estimators. We propose two different types of Bayesian density ratio estimators and compare their performance in terms of Bayesian risk function with themselves as well as the usual plug-in density ratio estimators. Some applications such as classification and divergence function estimation are addressed.

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Development and Sensitivity Analysis of an Empirical Equation for Calculating the Amplitude of Pressure Head Loss of Oscillating Water Flow in Different Types of Pipe

Water ◽

10.3390/w12092421 ◽

2020 ◽

Vol 12 (9) ◽

pp. 2421

Author(s):

Kai Zhang ◽

Baoxu Zhang ◽

Delan Zhu

Keyword(s):

Water Flow ◽

Empirical Equation ◽

Pressure Head ◽

Head Loss ◽

Model Parameters ◽

Pipe Material ◽

Efficient Operation ◽

Pipe Networks ◽

Different Types ◽

Relative Errors

Low pressure oscillating water flow can reduce the investment and energy consumption of irrigation. It is also effective in reducing the clogging of an emitter and improving the spraying quality of sprinklers. In order to overcome the problem of the complex process in calculating the amplitude of the pressure head loss of oscillating water flow in different types of pipes, in this study, an empirical equation for the amplitude of the pressure head loss of oscillating water flow in different types of pipe has been developed. Further, validation experiments have been conducted to verify the accuracy of the calculated amplitudes of the pressure head loss by the empirical equation. The results show that average relative error between the measured and the calculated amplitudes of the pressure head loss by the empirical equation is 10.77%. Since the relative errors are small, it is an indication that the amplitudes of the pressure head loss calculated by the empirical equation are accurate. For the empirical equation developed in this study, the sensitivity of the model parameters has been analyzed. The results show that the amplitude of velocity, the internal pipe diameter, and the length of pipe are classified as highly sensitive. The average velocity, the period of oscillating water flow, and the modulus of elasticity of the pipe material are classified as sensitive. The thickness of the pipe wall is classified as medium sensitive. Compared with the calculation models of the existing researches, the empirical equation reduces the number of parameters required to be calculated, by which many complicated calculations are avoided, which greatly improves the computing efficiency. This is conducive to the efficient operation and management of oscillating water flow in irrigation pipe networks and also provides help for the optimal design of irrigation pipe networks.

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A Parametric Bayesian Approach in Density Ratio Estimation

Stats ◽

10.3390/stats2020014 ◽

2019 ◽

Vol 2 (2) ◽

pp. 189-201

Author(s):

Abdolnasser Sadeghkhani ◽

Yingwei Peng ◽

Chunfang Lin

Keyword(s):

Loss Function ◽

Bayesian Approach ◽

Risk Function ◽

Density Ratio ◽

Ratio Estimation ◽

Function Estimation ◽

Different Types ◽

Ratio Estimators

This paper is concerned with estimating the ratio of two distributions with different parameters and common supports. We consider a Bayesian approach based on the log–Huber loss function, which is resistant to outliers and useful for finding robust M-estimators. We propose two different types of Bayesian density ratio estimators and compare their performance in terms of frequentist risk function. Some applications, such as classification and divergence function estimation, are addressed.

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WRINKLING ATOP SHAPE MEMORY MATERIALS

Surface Review and Letters ◽

10.1142/s0218625x12500102 ◽

2012 ◽

Vol 19 (02) ◽

pp. 1250010 ◽

Cited By ~ 8

Author(s):

L. SUN ◽

Y. ZHAO ◽

W. M. HUANG ◽

H. PURNAWALI ◽

Y. Q. FU

Keyword(s):

Surface Tension ◽

Surface Roughness ◽

Shape Memory Alloy ◽

Shape Memory ◽

Shape Memory Polymer ◽

Patterned Surfaces ◽

Advantages And Disadvantages ◽

Different Types ◽

Shape Memory Materials ◽

Processing Techniques

Many surface related properties, such as surface roughness, surface tension and reflection etc are heavily dependent on the surface morphology of materials. Patterned surfaces may have significant effects on these properties. In this paper, we compare wrinkles produced atop three different types of shape memory materials, namely, shape memory alloy, shape memory polymer and shape memory hybrid. We show the advantages and disadvantages of them in terms of the processing techniques and the resultant wrinkle patterns.

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