Papers by Keyword: Electrical

Abstract: In this study we have synthesized the iron and bismuth co-substituted BaTiO₃ ceramic, with the general formula: Ba_0.95Bi_0.05Ti_1-xFe_xO₃ for x=0.00 to 1.00, by solid state route. The impedance and electrical properties of these materials were investigated. The dispersion in conductivity in these ceramics can be described by Jonscher's power law and suggests a mechanism of conduction that is related to the Correlated Barrier Jump (CBH) model, according to which charge transport occurs between localized states due to a jump of the potential barriers. The conductivity results confirmed the semi-conductor behavior of these ceramics at high frequency region. The Nyquist plots for the different ceramics confirmed the simple electrical relaxation phenomena with the presence of a Debye-type relaxation phenomenon for x<040 of Fe content. While above this rete, the relaxation behavior is transformed into a Non-Debye phenomenon.

Abstract: The effects of Ga substitution at Mn site on electroresistance behaviour of La_0.85Ag_0.15MnO₃ compound prepared by solid-state reaction method were investigated. X-ray diffraction (XRD) measurement were recorded at room temperature and refined by employing Rietveld techniques. Ferromagnetic to paramagnetic transitions behaviour have been observed from ac susceptibility results. Resistivity-temperature curve with different applied currents of 1 mA and 5 mA showed metal-insulator, MI transition temperature, T_MI decreased with increased of the applied currents. The increased in applied current caused the maximum resistivity around T_MI to be decreased for both samples indicated increased in charge carrier density which resulting in drop of resistivity, hence, enhanced double exchange mechanism. The electroresistance (ER) effects have been investigated. The result showed that the ER effect increases when Ga is substituted.

Abstract: This contribution, based on literature review, presents a general overview of properties and applications of transparent conductive oxides, TCO. The requested properties of TCO are a high conductivity associated to high transparency in a wide wavelength range. The relation between the techniques used for deposition or growing TCO and the possibility of their doping with appropriate dopant and concentration were discussed relatively to their applications and properties. Thus, we present in this part, the various possible techniques for growing TCO and discuss the effect of the temperature on the functional properties. This self-consistent presentation is also considered to introduce a better understanding of the expected requirements for TCO integrated as transparent electrodes in photovoltaic cells and modules. These developments of TCO for photovoltaic applications will be presented in a second publication.

Abstract: Structure of amorphous carbon can be composed of sp² (graphite), or sp³ (diamond), or a combination of both, depending on their fractions. Therefore, many researchers were exploring to use it as solar cell material. This research used the amorphous carbon of bio-product as a basic material in the form of palmyra sugar which was synthesized through the heating and doping process to produce n-type and p-type semiconductors. This research aims to analyze the effect of dopant and deposition time on electrical properties. The heating process was carried out at 250°C and the doping process was carried out by adding NH₄OH for a-C:N and H₃BO₃ for a-C:B. The deposition process was carried out by the nano-spray method using a variety of deposition time on the ITO substrate. The result of scanning electron microscopy (SEM) showed that the film thickness increased with the increase of deposition time. Besides, the result of four-point probe (FPP) showed that the dopant can increase electrical conductivity, but the film thickness did not influence it. The electrical conductivity obtained was 5x10^-1 - 6x10^-1 S/cm. And the result of further analysis, it can be concluded that electrical conductivity was still in the range of semiconducting material.

Abstract: Zinc oxide (ZnO) nanorods were grown on the pre-seeded substrate using a facile, solution route technique. The multilayer self-assembly of polyaniline (PAni) and tetrasulphonated phthalocyanine (TSCuPc) on ZnO nanorods was monitored by FTIR, UV-Vis SEM and XRD. Infrared spectrum of the assembled layer showed peaks centered at 1589cm-1and 1504 cm-1, confirmed the presence of quinoid and benzenoid structures of PAni, while peaks centered at ~1165cm^-1and ~775cm^-1 provided evidence for the presence of TSCuPc species. Absorption spectra of the assembled layer show broadened peaks at ~600nm and ~700nm affirmed the presence of PAni and TSCuPc molecules. A linear increase in the absorbance level at these wavelengths was also observed upon increasing the number of bilayers. The surface modification of the ZnO nanorods after self-assembly was confirmed through SEM. The edges of the ZnO nanorods was observed to change from sharp to dull upon employing layer by layer deposition of PAni and TSCuPc. XRD pattern of the assembled layer showed broadened peaks at low 2Θvalues associated to the amorphous nature of the emeraldine base of PAni. Even so, the diffraction peaks in XRD patterns of ZnO nanorods and ZnO/(TSCuPc-PAni) multilayer have been indexed as hexagonally wurtzite structure. The multilayer deposition of PAni and TSCuPc on the surface of ZnO as monitored by UV-Vis spectroscopy and confirmed by FTIR, XRD, and SEM provides a new way of anchoring dye molecules without carboxylic moieties on the surface of metal oxides

Abstract: Indoor Lighting design of different types of buildings is a very challenging and technology oriented work. Building lighting designing has specific rules and regulations and can be varied depending upon the designers choice. As per National Building Code of India, buildings can be classified according to the use or the character of occupancy in one of the nine groups. These are Group A_(Residential), Group B_(Educational), Group C_(Institutional),Group D_(Assembly ),Group E_(Business), Group F_(Mercantile), Group G_(Industrial) ,Group H_(Storage) and Group J_(Hazardous) types of buildings. With the reduction of energy consumption, there should not be any sacrifice in quality and quantity of light required as per the lighting codes. The shortage of Electrical energy is increasing gradually. As it is the energy source of lighting, the lighting designers should be more concerned about energy efficient lighting system design. LED consumes less power than the conventional luminaires & maintains almost the same lighting level. So, lighting designers are using LED luminaires into their designs now a days. Also, renewable energy sources driven lighting systems should be used. It will be environmental friendly also. A proper lighting design requires consideration of the amount of functional light level provided, the energy consumed and the aesthetic effect supplied by the lighting system. The electrical lighting systems should also consider the impacts of, and ideally be integrated with, daylighting systems. Building lighting design focuses on three fundamental aspects of the illumination of buildings or spaces. The first is the aesthetic appeal of a building. Secondly, the ergonomic aspect: the measure of how much of a function the lighting can achieve. Thirdly is the energy efficiency issue to ensure that light is not wasted by over-illumination, light pollution, by illuminating vacant spaces unnecessarily or by providing more light than needed for the aesthetics or the task.

Abstract: The world’s energy requirement has been dominated by petroleum oil resources for years in many applications, especially in the area of electricity generation and utilization. Mineral oil application in power system equipment can be potentially hazardous to the environment, especially when there are incidents of transformer explosion, which caused spillages of oil to the soils or water streams and thereby pollute the surrounding environments. This paper is aimed at finding a substitute for the use of mineral oil as transformer oil. Experiments on breakdown voltages, flash points, pour points, viscosities, densities and insulation resistances on conventional mineral oil and some selected vegetable oils were conducted, analyzed and compared to the internationally accepted standards, ASTM (America Standard Test of Material). Rubber seed oil, Palm oil, Mellon oil, Ground oil and Palm kernel oil were found to have good electrical, chemical and thermal properties which the transformer oil has.

Abstract: The cobalt ferrite and chiral polyaniline/cobalt ferrite composites were synthesized by co-precipitation and in-situ polymerization method, respectively. The crystal structure and composition, electrical conductivity, optical rotation, dielectric loss and magnetic loss of the as-prepared samples were researched. It was found that the optical rotation (levorotation) of composites is less than that of chiral polyaniline (L-PANI), and increased with the increasing of L-PANI content. The conductivity of the composites with a mass ratio of L-PANI to cobalt ferrite above 0.4 was better than of pure L-PANI, and their dielectric loss was in accordance with the conductivity in variation trend.

Abstract: Energy harvesting from ambient environment vibration is a potential method to supply the low-power consumption devices. This paper demonstrates a new method to proceed energy harvesting using a piezoceramic. Both the mechanical and electrical excitations (hybrid stimulation) have been exerted on a piezoceramic. Current was measured though a current amplifier to calculate the induced polarization. By comparing the hybrid stimulation and the pure mechanical one, it can be found that the hybrid stimulation method enable to amplifier the harvested energy, which is promising to be used in energy harvesting and sensor applications.

Abstract: Mongolia is a consumer of e-products and their parts are imported from abroad. Currently, e-waste represents the biggest and fastest growing manufacturing waste. The objectives of this study are collecting and analyzing data from statistical reports of Mongolia and comparing them to other countries, and recommending an infrastructure of e-waste management in the existing legal environment. Thereby, all data was published by governmental entities and central statistical bureaus. An e-product, such as computers and TV’s are leading by their imported quantity in Mongolia. The e-waste is becoming one of the most challenging environmental issues because of its tendency to be incompatible for reuse and recycling. However, up to now, a main portion of e-waste is utilized through re-using (45.1%) and disposing (31.9%), and fewer amounts are recycled (23.0%) as was estimated in a study supported with the Japanese International Cooperation Agency (JICA), Japan, 2010. In conclusion, Mongolia needs to establish e-waste management by implementing core activities such as adapting experiences from high developed countries, harmonizing the corporation between in governmental entities and supporting business activities of recyclers and retailers. The green development policy was approved by the Mongolian Parliament in June, 2014. According to this new policy, it is needed to be applied recycling incentives to raise the environmental awareness of all stakeholders.