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Polyethylene Terephthalate (PET) is a polar polymer and is best known as the material that constitutes a soft drink bottle. PET has excellent physical properties, such as, high heat resistance, low cold resistance, solvent resistance, and so on. It is also used as an electrical insulation or a dielectric material. In previous studies [1], in stepwise method to increase the AC electric field, the simultaneous...
Nowadays, water pollution is one of the most important issues on which much attention has been paid. As an effective water treatment method, activated sludge process has been widely used for water purification. However, excess sludge that results from the water treatment still brings pollution to environment. Anaerobic digestion has been used in a broad range of applications in excess sludge stabilization...
The deformation and motion behaviors of droplets under electric field are important research tasks regarding the mechanisms of emulsion electric dehydration. In order to study the dehydration characteristics of droplets under a non-uniform electric field, the simulation model of droplets under a non-uniform electric field was established using the phase field method, based on Cahn-Hilliard formulation...
This research is conducted to analyze the efficiency of dielectric heating by increasing the input ports which are to be symmetrically model on the electrode plate. This analysis is considering of the electric field distribution and intensity in dielectric loads. The electric fields are caused by the electric power on electrode plates of the input ports to improve the thermals temperatures and electric...
Partial discharge (PD) activity within a void in a dielectric material is influenced by many factors. One of the factors is the applied voltage waveform on the material. In this paper, a two-dimensional (2D) model of a cylindrical void in polyethylene layers has been developed using finite element analysis (FEA) software. The model was used to simulate PD activity in the void under square waveform...
Surface potential and electric field measurement techniques are widely used for the investigation of the corona charging of dielectric surfaces in a wide range of industry applications. The aim of the present paper is to estimate which of these techniques are the most appropriate for characterizing the charging state of non-woven fibrous dielectrics, and point out the "noise factors" that...
A comparative study of the effect of electrical fields on bifurcation phenomena appearing in biaxially stretched slabs of Mooney-Rivlin and Ogden materials is described. The main conclusion of the analysis is that the stretch ratio at which the bifurcation appears crucially depends on both, the configuration of the system sample-electrodes, and the model used.
The electric polarization in polyethylene oxide com-plexed with LiClO4 has been investigated over the frequency range from 10 mHz to 10 kHz. The exciting electric fields have been chosen so high that nonlinear components in the dielectric response are evident. Nonlinear dielectric and conductive spectra are determined and their temperature dependence is studied. It is found that the nonlinear relaxation...
This paper analyzes sheet transportation using the principle of electrostatic induction motors. This sheet transportation method has the capability of positioning and feeding dielectric sheets in processes and can be an interesting alternative to the existing mechanical conveyor. Although electrostatic sheet transportation was previously proposed based on a unique actuation model, it had limitations...
Under continuous application of high electrical stresses, the insulation system of an underground power cable is subjected to long-term degradation that can eventually cause premature breakdown of the cable. This is as a result of electronic charges being injected into the dielectric material when intense electric field is applied. These charges will then interact with polymer molecules; causing even...
Dielectric elastomers have demonstrated most potential as muscle-like actuators because they can undergo large deformation, have a high energy density and a relatively fast response. The basic structure of a dielectric elastomer (DE) is simple - an elastomer film sandwiched between two electrodes. The electrodes that sandwich the elastomer play a key role in the electromechanical performance. The...
Nanotechnologies are now inevitable regardless of the scope. In electrical engineering, especially in the context of "major" power systems, insulating materials of tomorrow are in the field of nanotechnologies. These new materials are commonly called "nanodielectrics". Having conducted numerous studies on the intrinsic electrical properties of nanomaterials, we propose in this...
Under the step voltage, the non-linear conductivity dielectrics have the function of grading the electric field. But such materials have been applied extensively under AC electric field, and insulating materials damaged mostly under impulse voltage. The research on the AC response characteristic presents the foundations for the development and application of non-linear insulation dielectrics. In this...
The pattern of partial discharge (PD) occurrence at a defect site within a solid dielectric material is influenced by the conditions of the defect site. This is because the defect conditions, mainly its size and location determine the electric field distributions at the defect site which influence the patterns of PD occurrence. A model for a spherical cavity within a homogeneous dielectric material...
In order to distinguish minor differences of particulate morphologies and dielectric properties, a new method of particulate separation by different dielectrophoretic holding force is developed in this paper. The ability for particulate captive involving electric field distribution is studied, and two kinds of negative dielectrophoretic traps are designed correspondingly. It's found that the traps...
Water breakdown subjected to uniform DC electric field in 300 nm planar gaps is experimentally studied. Test devices with microstrip line configurations are fabricated through nanofabrication technology and the results show that water breakdown occurs at ~ 100 kV/cm electric field under current system setup. The initiation process of water breakdown in a small gap is discussed. It is most likely being...
Piezoelectric transformers are used as step-up voltage elements in many devices. The University of Missouri is developing a piezoelectric transformer as an accelerator for an ion beam. In cases where high voltage pulses are desired, discharges can result from a large electric field near triple point junctions. Due to the small scale of the device, conductive triple point shields are difficult to employ...
Polymers are extensively used as insulating material in high voltage devices, such as underground power cables, power capacitors and transformers. During normal operation the polymeric insulation of a power device is not only subjected to electrical stresses, but could also be subjected to thermal, mechanical and environmental stresses. These stresses either acting singly or in combination can cause...
Gas discharge model of vacuum circuit breaker based on fractal theory is established. For reflecting the influence of the variation of electric field on the discharge development, the gas discharge process was simulated and analyzed. Moreover, the combination effect of the electric field and the random consideration on the discharge was investigated. The whole spatio-temporal evolvement behavior of...
This paper deals with initiation of light emission and electrical trees in LDPE/MgO nanocomposite. Specimens were prepared in such a way that a tungsten needle of 50 mum phi and 1mumR was inserted into dielectrics with a spacing of 0.4 mm between high voltage and ground. Light emission was observed by an ICCD camera, and tree shapes were examined by an optical microscope. As a result, it was found...
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