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The current work reviews the importance of engineering the interface between nanofillers and polymers to achieve unique dielectric properties in nanocomposites. Although many improved dielectric properties of nanocomposites have been attributed to the presence of the interface, the interface can also be an attractive location for water to accumulate, which may otherwise jeopardize the dielectric properties of nanocomposites. Consequently, the use of surface functionalization and calcination techniques in removing water-related moieties on nanofillers is highlighted. Specifically, the effects of nanofiller calcination on two exemplar oxide-based nanocomposite systems, namely, silica-based nanocomposites and zirconia-based nanocomposites, are discussed. Evidence suggests that nanofiller calcination influences not only the water-related chemistry, but also the structure of oxide-based nanofillers. Significantly, for detailed interfacial chemistry of nanofillers to become relevant in engineering the dielectric properties of nanocomposites, effective removal of interfacial water on nanofillers is crucial.

The current work investigates the effects of filler calcination on the structure and dielectric properties of polyethylene/zirconia (ZrO 2 ) nanocomposites. Calcination temperatures of 600 and 900 °C have been applied to ZrO 2 in an attempt to modify its surface chemistry and structure. Calcination results in a slight reduction in the concentration of physically adsorbed water on ZrO 2 and, in addition, structural reorganization of the ZrO 2 nanopowder. Consequently, the real permittivity of nanocomposites containing calcined ZrO 2 is reduced compared to nanocomposites containing uncalcined ZrO 2 . Furthermore, the DC breakdown strength of nanocomposites containing calcined ZrO 2 improves compared to nanocomposites containing uncalcined ZrO 2 . Since the removed water content is minimal, we primarily attribute the observed dielectric results to structural changes in ZrO 2 rather than water-related effects. As such, calcining can have positive effects in enhancing the dielectric properties of ZrO 2 -based nanocomposites.

Polymer nanocomposites have become one of the attractive research areas in exploring new dielectric materials. This is due to their potential dielectric property enhancements as a consequence of nanostructuration. However, the degradation of the dielectric performance of nanocomposites has also been reported and this is can be related to the presence of water within the materials. The main objective of the current work was to investigate the effects of water absorption on the mass change and dielectric response of polyethylene (PE) nanocomposites containing uncalcined and calcined zirconia (ZrO 2 ) nanofillers. The results show that nanocomposites containing uncalcined ZrO 2 exhibited a marginal increase in the real permittivity after water immersion. Under similar water immersion periods, nanocomposites containing calcined ZrO 2 also demonstrated a marginal increase in the real permittivity. Factors influencing the dielectric response of the nanocomposites after ZrO 2 calcination and water immersion are discussed.

Polymer nanocomposites have become one of the vital research areas in exploring the prospective use of new dielectric materials. Thus far, there have been many positive dielectric results reported, especially for the use of polyethylene nanocomposites as electrical insulation. However, degraded dielectric performances of the materials have also been reported and, in some cases, these have been associated with the presence of water within the materials. In this paper, the effects of water absorption on the dielectric response of polyethylene (PE) nanocomposites containing uncalcined and calcined silicon dioxide (SiO 2 ) nanofillers are reported. The results show that immersing PE/SiO 2 nanocomposites under different water immersion periods changes the dielectric response of the materials. Specifically, nanocomposites containing uncalcined SiO 2 show a noticeable increase in the real permittivity after water immersion. Meanwhile, under similar water immersion periods, nanocomposites containing calcined SiO 2 show a lower real permittivity compared with those containing equivalent amounts of uncalcined SiO 2 . The mechanisms concerning water absorption of nanocomposites after SiO 2 calcination are discussed.

This paper reports on an investigation of the effects of calcination on the structure and dielectric properties of polyethylene/silica (SiO 2 ) nanocomposites. Calcination temperatures of 600 and 900 °C have been used in order to modify the surface chemistry and surface structure of the SiO 2 . The results show that, after calcination, the concentration of surface hydroxyl groups and water molecules around SiO 2 and within resulting nanocomposites is reduced. The real permittivity of nanocomposites containing calcined SiO 2 decreases compared to nanocomposites based on uncalcined SiO 2 . The DC breakdown strength of nanocomposites containing calcined SiO 2 becomes higher than those containing uncalcined SiO 2 . In contrast, AC breakdown was found not to be significantly affected by addition of any of the silicas considered here. The use of calcined nanofillers can have positive effects akin to the use of chemically functionalized nanofillers in enhancing the dielectric properties of nanocomposites; both approaches remove polar surface hydroxyl groups.

For last decades, the topic of polymer nanocomposites have been widely studied in the scientific literature since the material system promises a substantial dielectric properties enhancement even at low nanoparticles loading. Nevertheless, factors contributing to increased or decreased DC breakdown strength of nanocomposites are far from understood. In this paper, an investigation on the DC breakdown strength of polyethylene nanocomposites that contained different amounts of silicon nitride with different non-isothermal crystallization processes is reported. The non-isothermal crystallization techniques were determined by fast, medium and slow cooling rate conditions by the differential scanning calorimetry (DSC) for all the nanocomposite samples. The chemical structures of the nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy and the morphology of the nanocomposites was determined by scanning electron microscopy (SEM). From DC breakdown testing, the breakdown results of the nanocomposites were found to vary under different non-isothermal crystallization conditions.

Polymer nanocomposites have become one of the main research studies in investigating the potential use of new dielectric materials especially in high voltage insulation. Many promising results, especially on the use of polyethylene nanocomposites as dielectric materials, have been reported in the literature. Significantly, the main factor that affects the dielectric performance of the materials was attributed to the interface between the host matrix and the nanofiller. This paper reports on an investigation into the AC and DC breakdown performance of unfilled and polyethylene nanocomposites containing silicon dioxide (SiO2) nanofillers at different loading levels (1 wt%, 4 wt%, and 8wt%). By using the Fourier transform infrared (FTIR) spectroscopy, the chemical structures of the materials were characterized. The dielectric permittivity of the samples was analyzed using dielectric spectroscopy. From the breakdown results, it showed that AC breakdown testing did not result in significant changes on the breakdown strength between uncalcined and calcined nanofillers. Meanwhile, for DC breakdown testing, introducing a small number of nanofillers could have a major impact on the DC breakdown strength. These results were correlated with the calcination process of nanofiller; the DC breakdown strength improved for calcined nanofiller compared to uncalcined nanofiller.

Polymer nanocomposites has a huge potential to serve as dielectric materials. These materials were found to have a great capability in withstanding high voltage levels. In nanocomposites development, the breakdown strength of the materials was often reported to be higher, lower or similar, in comparison with the unfilled polymer. Because of this, the breakdown performance of nanocomposites is said to be dependent not only on the polymer/nanofiller combination, but also on the sample preparation techniques. Unfortunately, factors leading to increased or decreased the breakdown strength of nanocomposites are less understood. In this paper, investigation into polyethylene blend systems that contain different amounts of silicon nitrite nanofiller with different non-isothermal crystallization processes was reported. The non-isothermal crystallization techniques were determined by fast, medium and slow cooling rate conditions while preparing the samples. Differential scanning calorimetry (DSC) was used to characterize the thermal behavior of the polymer nanocomposites. The AC breakdown data showed that the use of different non-isothermal crystallization techniques affected the AC breakdown strength of each material type.

Good electrical insulation systems are often characterized by its electrical performances. However, the development of new electrical insulation systems has become more challenging due to increased demands for higher voltage levels. For this, the topic of polymer nanocomposites has become popular among dielectric researchers since the material system promises excellent dielectric strength if properly engineered. In this paper, an investigation on the DC breakdown strength of polyethylene nanocomposites that contained different amounts of nanosilica with different non-isothermal crystallization processes is reported. The non-isothermal crystallization techniques were determined by fast, medium and slow cooling rate conditions while preparing the nanocomposite samples. The chemical structures of the nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy and the morphology of the nanocomposites was determined by scanning electron microscopy (SEM). From DC breakdown testing, the breakdown results of the nanocomposites were found to vary under different non-isothermal crystallization conditions.

Polymer nanocomposites have become one of the main research studies in exploring the potential use of advanced insulating materials in high voltage insulation. From previous research on nanocomposites, promising results of polyethylene nanocomposites have been reported, and the interface between the base polymer and the nanofiller has been attributed as one of the factors affecting the dielectric breakdown performance. This paper reports on an investigation into the DC breakdown performance of unfilled and polyethylene nanocomposites containing silicone dioxide (SiO 2 ) and zirconium oxide (ZrO 2 ) nanofillers at 1 wt%, 4 wt%, and 8wt% loading levels. The chemical structures of the materials were characterized using Fourier transform infrared (FTIR) spectroscopy and the morphology of the materials were determined using scanning electron microscopy (SEM). The breakdown results showed that, introducing small amounts of nanofillers could have a major impact on the DC breakdown strength. Nevertheless, samples containing ZrO 2 had higher breakdown strength than those containing SiO 2 . The mechanisms governing these changes are discussed.

In electrical insulation, polymer nanocomposites become one of the main research areas for exploring the potential of insulating materials in terms of dielectric strength enhancement. This is due to many promising results of nanocomposites reported by the dielectrics community. For this, the interfaces between the filler and base polymer is one of the major factors for improving the filler/ polymer interaction within the nanocomposites. This paper reports on an investigation into the AC breakdown performance of unfilled and nanofilled polyethylene. With different nanofillers (silicone dioxide (SiO 2 ) and zirconium oxide (ZrO 2 )) and different loading levels (1 wt%, 4 wt%, 8 wt%). The thermal behavior of the materials was characterized using differential scanning calorimetry (DSC) and the melting traces for the materials were determined. The breakdown results showed that a low nanofiller loading level (1 wt%) did not significantly affect the breakdown strength compared to the unfilled sample. When comparing samples containing SiO 2 and ZrO 2 nanofillers, it appeared that those with ZrO 2 filler had slightly higher breakdown strength compared to those containing SiO 2 nanofiller. The significance of the results is discussed.

Photovoltaics (PV) system converts light into electric current using the photo-electric effect. Due to the growing demand for renewable energy sources, the manufacturing of solar cells and PV system arrays has advanced considerably in recent years. However, lightning protection on photovoltaic material is very crucial to avoid strike damage caused by transient overvoltage to the photovoltaic system that may due to a direct or an indirect strike. There is no experimental study recently to show the profile of unwanted signals due to induced overvoltage that is coupled to the solar panel system or related material. It is consequently imperative that experimental work to investigate the unwanted signal that is coupled to the solar panel material be conducted. In this study, the experimental set up of induced overvoltage was conducted in which the unwanted signal due to induced voltage was created by the short spark gap. The experiment was conducted in a High Voltage lab in University Teknikal Malaysia Melaka (UTeM) using artificial lightning discharge of 1.2/50μs with the peak voltage of 33 kV. The distance between the solar panel and spark gap was varied in order to study the relationship between the maximum voltage of unwanted signal and the distance. The existence of unwanted signal due to induced voltage with of maximum voltage profile was observed and is discussed in detail in the result and discussion sections.

Mixed matrix membranes (MMM) comprised of multi-walled carbon nanotubes (MWCNTs) inside polyethersulfone (PES) matrix were fabricated and characterized for gas separation performance. The MWCNTs were purified with acid mixtures (HNO3/H2SO4; v/v = 1:3) to remove carbonaceous impurities followed by surface functionalization with 3-aminopropyltriethoxylsilane (APTES) to allow well dispersion of the tubes in organic solvent such as N-methlypyrrolidone (NMP) during the preparation of PES/MWCNTs suspension. Effects of purification, functionalization and MWCNTs loading on the gas permeation properties of the MMM were investigated by varying the MWCNTs loading in the PES matrix from 0.5–3.0 wt.%. The fabricated MWCNTs/PES MMM were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA) and pure gas permeation test. Gas permeation measurement showed that MMMs embedded with different kinds of applied CNTs exhibited different separation performances. For example, gas permeation measurement showed that MMM embedded with 1.0 wt.% purified and functionalized MWCNTs possessed better performances in terms of permeability and selectivity in comparison to raw MWCNTs. The highest gas selectivity was achieved at 0.5 wt.% MWCNTs loadings (aCO2/CH4 = 250.13; aO2/N2 = 10.65) and decreased as the loadings were increased from 1.0 to 3.0 wt.%. The reduction in performance possibly due to the presence of interface voids which became prominent at higher MWCNTs loading. The high selectivity of fabricated MMM suggested that the present works have a great potential to be utilized practically in gas separation technology.

Lightning is one type of transient faults that usually cause the circuit breaker in the distribution board trip due to overload current detection. The instant tripping condition in the circuit breakers clears the fault in the system. Unfortunately most circuit breakers system is manually operated. The power line will be effectively re-energized after the clearing fault process is finished. Auto-reclose circuit is used on the transmission line to carry out the duty of supplying quality electrical power to customers. In this project, an automatic reclose circuit breaker for low voltage usage is designed. The product description is the Auto Reclose Circuit Breaker (ARCB) will trip if the current sensor detects high current which exceeds the rated current for the miniature circuit breaker (MCB) used. Then the fault condition will be cleared automatically and return the power line to normal condition. The Global System for Mobile Communication (GSM) system will send SMS to the person in charge if the tripping occurs. If the over current occurs in three times, the system will fully trip (open circuit) and at the same time will send an SMS to the person in charge. In this project a 1 A is set as the rated current and any current exceeding a 1 A will cause the system to trip or interrupted. This system also provides an additional notification for user such as the emergency light and warning system.

Lightning produces extremely high voltages that generated induce overvoltage which have a high tendency to effect the electrical apparatus especially renewable energy plant that directly expose to this source. This study was performed through experimental work by investigating the effect of induce overvoltage upon the photovoltaic system. The induce voltage was performed by using lightning impulse generator. It is found that the maximum voltage of the unwanted signal is proportional with the distant of the specimen. The closer distant between solar panel material and spark discharge, the more serious effect would occur due to the induced overvoltage.

Insulations in high voltage engineering are a concern to users in terms of its performance, expected lifetime, and long-time reliability. Insulation failure can allow leakage current (LC) to flow and causes tracking and erosion as well as flashover. Tracking and erosion test complying with BS EN 60857-2007 are conducted to capture the set of leakage current (LC) patterns which are capacitive, resistive, and discharge activities. For verifying the performance of the insulators, an automated monitoring system is needed to reduce diagnostic time of the LC. Even though Fast Fourier Transform (FFT) gives useful information on the analysis of LC, it has limitation in nonstationary signal. Therefore, this research presents the analysis of time frequency distribution (TFD) which is spectrogram that represents the LC signals in the joint time frequency domains which provide temporal and spectral information. The results obtained from the developed monitoring system allow the user to identify leakage current performance in real time. The developed system has shown the capability in detecting the performance of insulating materials as well as identifying the characteristics of the surface discharges.

The paper presents the validity of using Central Pattern Generator (CPG) model to develop one leg hopping robot which hops higher and rhythmically. Infrared Ranging (IR) sensor is mounted on a platform to measure the distance of hopping performance. The distances of IR sensor from the platform to the floor in both static and vertical jumping motion are measured. MATLAB & Simulink model including CPG model is designed to evaluate the performance of IR sensor by converting the measurement data from IR sensor from voltage to distance by using function blocks. The result shows that the one leg hopping robot with CPG model is able to achieve maximum hopping height at 4cm.

This paper discussed on evaluation and validation of method in order to generate the moving motion control system of the developed tripod hopping robot. The proposed method to control the system is designed by using MATLAB&Simulink which consist of reference height control system and the networks of Central Pattern Generator (CPG) that can controlled the hopping height of each leg independently. By using this method, one of the legs of the tripod hopping robot is set to different value than the other leg in order to make the posture of hopping robot's body incline ahead towards to the direction which it should move, respectively. As the result, the effectiveness of the approached method to generate moving motion of the hopping robot using CPG networks that including the reference height control system is confirmed while maintain the stability of developed tripod hopping robot from tumbled ahead.

In this paper, the generation of vertical jumping motion for tripod hopping robot through reference height control system method in order to converge the differences of reference height for each leg of tripod hopping robot is discussed. The proposed control system is designed using MATLAB/ Simulink which is consisted of maximum height detector, PI controller system in the system of Central Pattern Generator (CPG). By using the approached method, tripod hopping robot can maintain the hopping motion and control the jumping height to achieve the reference height. As the result, we evaluate the effectiveness of CPG networks to keep the stability of tripod hopping robot besides of confirm the validity of using reference height control system to generate moving capability at different reference height.

Lightning produces extremely high voltages that generated induce overvoltage which have a high tendency to effect the electrical apparatus especially renewable energy plant that directly expose to this source. This study was performed through experimental work by investigating the effect of induce overvoltage upon the photovoltaic system. The induce voltage was performed by using lightning impulse generator. It is found that the maximum voltage of the unwanted signal is proportional with the distant of the specimen. The closer distant between solar panel material and spark discharge, the more serious effect would occur due to the induced overvoltage.