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Highlight • Under DC voltage, surface charge indicates polarity effect. • Increasing the voltage amplitudes led to an increase of the surface charge density. • Corona voltage and the charging time for both polarities rise, the amount of charges increases linearly. • Relationship between amount of surface charges and number of photons have been carried out using corona camera. Abstract The objective of the present study is to investigate the surface charge measurement on the surface of polymeric insulator under AC and DC voltages experimentally. According to the test results, increasing the voltage amplitudes led to an increase of the surface charge density, the voltage application duration was also extended. During the tests, it was observed that as the corona voltage and the charging time for both polarities rise, the amount of charges increases linearly. The results show that more surface charge was deposited by negative corona charging when compared with positive corona charging. Also in this paper, the effect of the corona variations on the amount of surface charge have been investigated. For this purpose, relationship between amount of surface charges and number of photons have been carried out using corona camera. Moreover, attempt was made to investigate the effects of surface charges on potential and electric field distribution along polymeric insulator under AC and DC voltages using computer simulations based on finite element method (FEM). The present paper was conducted to study the effects of magnitude, polarity, and location of surface charges on surface potential distribution along the insulator. [ABSTRACT FROM AUTHOR]

Abstract There are different approaches to solve the three-dimensional (3D) resistivity model. In this research, a new modeling technique has been developed to solve 3D potential distribution in a resistor network. This method uses the Kirchhoff's law for discretizing a resistor network. This different approach for the 3D resistivity modeling helps to describe an arbitrary 3D model using a resistor network. This method has no singularity constraint, although there is no need to apply any singularity removal techniques. The resistor network can be used for any electrode configuration. The potential distributions at all nodes are simultaneously solved for each injection source. Sensitivity matrix and potential distribution in both models are compared. Experiments with various physical models and numerical models show the similarity of the method with traditional resistivity modeling. Comparing the result of this approach with other methods shows better sensitivity away from edges. Furthermore, a parallel programming technique is used to improve the processing time. Flexibility and extensibility to build any resistivity model make this approach a powerful modeling tool in 2D and 3D electrical resistivity forward modeling. [ABSTRACT FROM AUTHOR]

In this paper we provide numerical results for the electrostatic potential profile of a soft charged particle with a charged core and pH-dependent charge density. The present study serves as a useful platform for better quantification of the electrostatic potential profile of the MS2 bacteriophage virus. In this context, this work improves the analysis of a similar recent study [Phan et al., J. Chem. Phys. 139 (2013) 244908] in two aspects. First, as compared to the previous study, we provide numerical rather than analytical results for the electrostatic potential profile. This is important because the analytical treatment forbids the investigation of cases with intermediate to large charge density, relative to the bulk charge density of the electrolyte, of the viral surface. Second, the consideration of pH-dependent charge density in the electrostatic potential profile is a more credible representation of the electrostatics of the virus, which is known to demonstrate pH-dependent variation in the electrophoretic mobility. In fact, we establish that the various predictions on the electrostatic potential profile made in the previous study are substantially modified when the effect of pH is considered, and the result must now be described in terms of the difference pH − p K a , where K a refers to the ionization constant of the acid that produces the PEL ions. [ABSTRACT FROM AUTHOR]

This paper presents an analytical model for the potential distribution of a p-n-i-n tunneling field effect transistor (TFET). Using the potential distribution, the tunneling drain current is derived analytically by integrating the band-to-band tunneling generation rate over the device volume. According to our knowledge, there is no analytical analysis for this structure in the literature, and this is the first analytical model proposed for a p-n-i-n TFET structure. The proposed analytical model is validated via numerical results obtained from device simulations based on non-local band-to-band tunneling model. [ABSTRACT FROM AUTHOR]

Highlights: [•] Develop a numerical model to simulate potential and current density at defects. [•] Determine the potential distribution inside the defect under cathodic protection. [•] Evaluate effectiveness of cathodic protection at defects on pipelines. [•] Derive empirical equations for corrosion defect assessment. [Copyright &y& Elsevier]

Highlights: [•] More uniform potential distribution for diagonal grid configuration vs. others. [•] Optimized diagonal grid configuration enhances current collecting ability. [•] Numerical modeling, a fast and inexpensive method for grid optimization. [Copyright &y& Elsevier]

Abstract: The Poisson–Boltzmann theory is still considered as an exact theory under low or even moderate electrolyte concentrations. As of today, however, just the analytical solutions in a single electrolyte were obtained, while people often meet mixed electrolytes in practical applications. Thus the analytical solutions of Poisson–Boltzmann equation (PBE) in different mixed electrolytes are still an important issue. The analytical solutions of PBE in mixed electrolytes with monovalent and bivalent counterions were firstly derived in the present study. The potential distribution and concentration profile curves in EDL were obtained with one dimensional space by the analytical solutions of PBE. The potential distribution curves of different mixtures showed that the power of the screen surface charge for bivalent counterion was stronger than that for monovalent counterion, thus the concentration of bivalent counterion in EDL was larger than that of monovalent counterion. [Copyright &y& Elsevier]