Theoretical Principles of Streaming Current Detection

1989 ◽  
Vol 21 (6-7) ◽  
pp. 443-453 ◽  
Author(s):  
S. K. Dentel ◽  
K. M. Kingery
Keyword(s):  
Velocity Profile ◽  
Electrophoretic Mobility ◽  
Double Layer ◽  
Initial Attempt ◽  
Streaming Current ◽  
Coagulant Dosage ◽  
Model Predictions ◽  
Double Layer Model ◽  
Simplifying Assumptions ◽  
Current Detection

In spite of the increased use of streaming current detectors (SCDs) as a means of monitoring and/or controlling coagulant dosage, knowledge regarding fundamental workings is incomplete. This paper provides an initial attempt at predicting and verifying functioning compared to electrophoretic mobility. The instrument's components -- the sensor and the signal processor -- are first described. Equations modelling electro-double layer behavior in its sensor are then developed. Simplifying assumptions include the use of a capacitance model of the double layer and a triangular velocity profile for fluid within the sensor's annulus. More complex modelling approaches are also suggested which incorporate the Gouy-Chapman electro-double layer model and an exact solution for the velocity profile. Experimental results confirm predictions of the simplified model under conditions of low potential. A monotonic relationship exists between streaming current electrophoretic mobility, which is required for its use as a control parameter. Deviations from model predictions are suggested to be due to charge characteristics of the sensor surfaces themselves.

A discussion on the leaching process of the ion-adsorption type rare earth ore with the electrical double layer model

2018 ◽  
Vol 120 ◽  
pp. 35-43 ◽  
Author(s):  
Xiao Yanfei ◽  
Gao Guohua ◽  
Huang Li ◽  
Feng Zongyu ◽  
Lai Fuguo ◽  
...  
Keyword(s):  
Rare Earth ◽  
Double Layer ◽  
Electrical Double Layer ◽  
Ion Adsorption ◽  
Layer Model ◽  
Leaching Process ◽  
Double Layer Model

scholarly journals Modeling the AC Electrokinetic Behavior of Semiconducting Spheres

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 100 ◽  
Author(s):  
Pablo García-Sánchez ◽  
Jose Flores-Mena ◽  
Antonio Ramos
Keyword(s):  
Double Layer ◽  
First Principles ◽  
Electrical Double Layer ◽  
Aqueous Electrolyte ◽  
Interfacial Phenomena ◽  
Double Layers ◽  
Electrical Double Layers ◽  
Model Predictions ◽  
Doped Silicon ◽  
Arbitrary Thickness

We study theoretically the dielectrophoresis and electrorotation of a semiconducting microsphere immersed in an aqueous electrolyte. To this end, the particle polarizability is calculated from first principles for arbitrary thickness of the Debye layers in liquid and semiconductor. We show that the polarizability dispersion arises from the combination of two relaxation interfacial phenomena: charging of the electrical double layer and the Maxwell–Wagner relaxation. We also calculate the particle polarizability in the limit of thin electrical double layers, which greatly simplifies the analytical calculations. Finally, we show the model predictions for two relevant materials (ZnO and doped silicon) and discuss the limits of validity of the thin double layer approximation.

Effects of Various Parameters on Nanofluid Thermal Conductivity

2006 ◽  
Vol 129 (5) ◽  
pp. 617-623 ◽  
Author(s):  
Seok Pil Jang ◽  
Stephen U. S. Choi
Keyword(s):  
Thermal Conductivity ◽  
Thermal Behavior ◽  
Volume Fraction ◽  
Heat Transfer Fluids ◽  
New Concepts ◽  
Model Predictions ◽  
Simplifying Assumptions ◽  
Thermal Phenomena ◽  
First Time ◽  
Good Agreement

The addition of a small amount of nanoparticles in heat transfer fluids results in the new thermal phenomena of nanofluids (nanoparticle-fluid suspensions) reported in many investigations. However, traditional conductivity theories such as the Maxwell or other macroscale approaches cannot explain the thermal behavior of nanofluids. Recently, Jang and Choi proposed and modeled for the first time the Brownian-motion-induced nanoconvection as a key nanoscale mechanism governing the thermal behavior of nanofluids, but did not clearly explain this and other new concepts used in the model. This paper explains in detail the new concepts and simplifying assumptions and reports the effects of various parameters such as the ratio of the thermal conductivity of nanoparticles to that of a base fluid, volume fraction, nanoparticle size, and temperature on the effective thermal conductivity of nanofluids. Comparison of model predictions with published experimental data shows good agreement for nanofluids containing oxide, metallic, and carbon nanotubes.

A Double-Layer Model for Foreground Detection from Video Sequence

2011 ◽  
Author(s):  
Hunaxi Liu ◽  
Junchi Yan ◽  
Jun Zhu ◽  
Xiaowei Lv ◽  
Xiong Li ◽  
...  
Keyword(s):  
Double Layer ◽  
Video Sequence ◽  
Foreground Detection ◽  
Layer Model ◽  
Double Layer Model

Determination of Engine Roughness Using Multi-Physics Numerical Predictions

2005 ◽  
Author(s):  
M. Perera ◽  
S. Theodossiades ◽  
H. Rahnejat
Keyword(s):  
Film Formation ◽  
Structural Deformation ◽  
Experimental Investigations ◽  
Tribological Behaviour ◽  
Load Bearing ◽  
Numerical Predictions ◽  
Engine Design ◽  
Model Predictions ◽  
Simplifying Assumptions ◽  
Experimental Findings

The paper presents a detailed engine modelling method, referred to as a multi-physics approach, in which combined rigid body inertial dynamics, structural modal characteristics of elastic components and tribological behaviour of load bearing surfaces can be studied within a single analysis. This approach is regarded as holistic and a good aid for detailed design. Of particular interest is the evaluation of behaviour of critical elements in the system, such as the load bearing conjunctions (e.g. crankshaft engine bearings). Another important feature is the inclusion of study of motion across the physics of scale, from micro-scale fluid film formation in bearings to sub-millimetre structural deformation of components and large displacement inertial dynamics. In order to arrive at predictions within sensible industrial time scales, it is essential to include, as far as possible, modelling features of analytical rather than numerical nature, which necessitates inclusion of some simplifying assumptions. When such an undertaking is made, the validity of model predictions must be gauged against experimental findings to enhance confidence in the use of the method. The paper shows good conformance between model predictions and experimental investigations. It further shows that some important issues in engine design and development can be addressed in a satisfactory manner, paving the way for reduction in the empirical or iterative nature of engine design evaluation.

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