Papers by Keyword: Electronics

Abstract: Paper investigates the possibility of producing silicon from silica contained in Shoda-Kedela (Oni-Gebi district, Georgia) quartz deposition. Characterization of silica from Shoda-Kedela quartz rock is carried by its crushing, grinding, thermal analysis, studying composition and density. Metallurgical grade silicon (MG-Si) is obtained by reducing Shoda-Kedela quartz in its reaction with coke in an electric arc furnace at temperature of ~1800°C. The obtained in this way material reveals that Shoda-Kedela silica containing of 99.58% SiO₂ would be useful for developing the silicon high-technology production.

Abstract: We have developed composite paint based on graphite, carbon black and some other not expensive components, which can be used as a clay court for sustainable buildings and electronic devices. This paint can reduce sufficiently the problem, which is related to the effects of electromagnetic radiation (EMR) on human health. Cellular and radiotelephones, as well as their broadcast antennas, especially which use of the 5G, 6G communication system, may pose a high risk of cancer, reproductive disorders, memory, cellular stress, neurological and mental disorders. The medical disorders are already often experienced by servicemen working at radar stations, observation posts and other similar facilities associated with high-frequency EMR. The effect of EMR is especially dangerous for children of preschool and school age, so, it is necessary to use similar paints first of all for such buildings. Carbon-based composite paints have been developed, which can be used as a clay court for sustainable buildings and electronic devices. This paint can reduce sufficiently the problem, which is related to the effects of electromagnetic radiation (EMR) on human health. Cellular and radiotelephones, as well as their broadcast antennas, especially which use of the 5G, 6G communication system, may pose a high risk of cancer, reproductive disorders, memory, cellular stress, neurological and mental disorders. The medical disorders are already often experienced by servicemen working at radar stations, observation posts and other similar facilities associated with high-frequency EMR. The effect of EMR is especially dangerous for children of preschool and school-age, so, it is necessary to use similar paints first of all for such buildings. It is also necessary to note the significant impact of EMR on electronic equipment. First of all, this is a well-known problem of providing the so-called "electronic compatibility", when simultaneously operating different electronic equipment (e.g., thermal imager and radio transmitter) interfere with each other. A number of scientific developments have been implemented and work is underway under the NATO SfS international grant in this area.

Abstract: Magnetoelectric materials which simultaneously exhibit ferroelectricity and magnetism have attracted great attention in recent years due to their potent coupling effect, and potential application in the electronics industry. The work done in this study aims to investigate the effect of ferromagnetic (Fe₃O₄) nanoparticles on the thermal, mechanical, magnetic, and ferro-electrical properties of PVDF, and its co-polymer poly (vinlydene fluoride-co-trifluoroethylene), P (VDF-TrFE). These compounds are synthesized into flexible nanocomposite thin films, via a novel solvent casting method to influence crystallization and nucleation growth. Fe₃O₄ nanoparticles (NP) were integrated with polymers at varying weight percentages (1wt%, 3wt%, 5wt%, 7wt%, and 10wt %). Magnetoelectric nanocomposites were annealed at 150oC. Films were fabricated and processed at dimensions: 8-20μm thickness, 35 mm length, and 35 mm width. Neat and loaded samples are characterized using x-ray diffraction (XRD) to observe crystallinity and to obtain β - phase content distribution. Ferroelectric hysteresis loops are given from Radiant Multiferroic Analyzer, which resulted in an increase in peak polarization of 9.601μC/cm² with the addition of 5wt% magnetite nanoparticles to P(VDF-TrFE) polymer blend. Magnetic tests are done using Vibrating Sample Magnetometer (VSM), which yields the magnetic polarization with respect to changes in field magnitude. The highest magnetic moment occurs with the addition of 10wt% Fe₃O₄ nanoparticles at 3.66 emu/g. Target applications of nanocomposites are for microelectromechanical system (MEMS) devices such as memory cards, spintronic, sensors, electromagnetic shielding, and compact energy storage.

Abstract: Recent advances in rheocasting have resulted in significant expansion in the types of products currently in full commercial production. The current paper gives an overview of components in production in Europe and in China produced using the RheoMetal^TM process, that has taken the lead in a strong drive towards new heavy-duty applications made from aluminium alloys. In China, the dominating applications are found in the telecom industry. The trend in Europe is more towards marine and automotive applications commonly in fatigue loaded applications. The reason for the choice of rheocasting for complicated shape thin-walled electronics components with requirements is dominated by process yield and by the ability to improve thermal conductivity. The heavy-duty truck chassis thick walled components target weight reduction through design and to sustain fatigue load normally requiring forged components. Common in all applications are seen in production yield, reduced tool wear and reduction of die soldering.

Abstract: This work aims to characterize the non-polymeric components, usually present as additives to perform different functions, present in the polymer housing of post-consumer computer monitors, in order to help finding the most adequate recycling destination for such material. The non-polymeric fraction was characterized by thermogravimetry (TG), loss on ignition (LOI), chemical analysis by X-ray fluorescence (XRF), and atomic absorption spectroscopy, scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), and X-ray diffraction (XRD). TG analysis indicated that the polymer has about 4 wt% of inorganic materials (performed in N₂ atmosphere), whereas LOI (performed in ambient atmosphere) indicated just 0.07 wt%. The XRF, SEM/EDS analyses, and atomic absorption spectroscopy of the post-fired material confirmed the presence of many elements. Nonetheless, toxicological relevant elements showed acceptable concentration levels, below 0.01 ppm. The XRD analysis indicated the presence of crystalline phases based on CaCO₃, SiO₂ and TiO₂.

Abstract: Thermal management of electronics is quite important for safe operation of nuclear rescue robot. However, the ambient temperature of the nuclear robot in the site of nuclear accident will suffer an alternation between ordinary and elevated temperature. Traditional phase change material (PCM) based closed scheme for thermal protection is not suitable due to the capacity limitation of PCM. Open scheme with forced air cooling or water cooling is not acceptable either, because it cannot operate in high temperature. Therefore, a semi-open thermal control scheme is proposed by using silica aerogel for heat insulation, PCM for heat absorption, and Nickel-titanium alloy spring as temperature switch. An investigation on different ambient temperature, laying angle, melting point of PCM and heat power is conducted. The results showed that, compared with the PCM-based closed scheme, our design can provide 19.23% prolonged safe working hours, which can improve the reliability of electronic devices.

Abstract: This work describes the fabrication and test of a high temperature (+200°C) capable high frequency transformer. It was manufactured using Low Temperature Co-fired Ceramic (LTCC) technology, which allowed the complex multilayer structure of ceramic and metal windings to be formed. However, the selected LTCC composition is a free sintering ceramic and there is an interaction between the metal conductor and the ceramic substrate during lamination and firing that can lead to significant deformation, presenting a significant engineering challenge. Here the fabrication process for the LTCC is described (screen printing, collation, lamination and firing) for a number of iterations of the transformer design, each of which was analysed for deformation and subjected to electrical tests. In addition a silicone adhesive for assembling the LTCC with the transformer was analysed for high-temperature performance. A test vehicle was assembled and it was subjected to 1000 hours at 210°C. Shear tests were performed at intervals to quantify the loss in bond strength over time. After a good solution for manufacture was found, a batch of transformers was produced, characterized and tested to demonstrate a high reproducibility and manufacturing yield.

Abstract: Recently, the field of Prognostics and Health Management (PHM) for electronic products and systems has received increasing attention due to the potentialities to provide early warning of system failures, reduce life cycle costs, and forecast maintenance as needed. This paper introduces the sensors and their sensor technologies. The required attributes of sensors for the development for PHM of electronics are discussed. Finally, their trends in sensor systems are presented.

Abstract: Model-Based Design (MBD) method is applied to power electronics device software development to overcome the problem of low efficiency in manual programming. The concept of Model-Based Design and several common development platforms are introduced. Based on tools in Simulink, an on-board charger control software is developed. Meanwhile the hardware platform, the model building, the model validation and the automatic code generation are also described. Experiments are carried out in the hardware platform to verify the correctness and feasibility of the codes.They are helpful for the software development of power electronics equipments.

Abstract: A microscope to image weak magnetic fields using a low-temperature superconducting quantum interference device (SQUID) had developed with a liquid helium consumption rate of ~0.5L/hour. The gradient pickup coil is made by a low-temperature superconducting niobium wire with a diameter of 66 μm, which is coupled to the input circuit of the SQUID and is then enwound on the sapphire bobbin. Both of the pickup coil and the SQUID sensor are installed in a red copper cold finger, which is thermally anchored to the liquid helium evaporation platform in the vacuum space of the cryostat. To reduce the distance between the pickup coil and sample, a 100 μm thick sapphire window is nestled up to the bottom of the cryostat. A three-dimensional scanning stage platform with a 50 cm Teflon sample rack under the sapphire window had the precision of 10 μm. To test the fidelity of the new facility, the distribution of the magnetic field of basalt slice specimens was determined. Results show that the spatial resolution of the newly-designed facility is 500 μm with a gradient magnetic field sensitivity of 380 fT. This opens new opportunities in examining the distribution of magnetic assemblages in samples, which bear great geological and geophysical information.