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Recycling of Broken Waste Glass as Polyethylene Nanofiller for Electrical Insulating System
(2022-01-01)
Vittayakorn, W.
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Khunna, D.
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Buaphuen, P.
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Vittayakorn, N.
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Makcharoen, W.
This work focuses on the preparation of a high-quality glass powder from the broken windowpane. The expected glass powder must show a high amount of silicon dioxide with fine particle size. The processing technique used in this work is coarse grinding and high-speed vibratory milling under a variety of conditions to get the best quality of glass powder. The particle size and particle size distribution were examined by using DLS technique. The chemical composition was examined by EDX together with FT-IR and XRF spectroscopies. The results showed that the wide range of particle size distribution occurred in all milling conditions, which approximately ranged from 0.3 to 7 µm, and the 270 min-milling time showed the smallest particle size of glass powder. The chemical analysis showed that the glass powder is rich in silica which contained about 70.47% of SiO<inf>2</inf>. After that, the various ratios of the glass powder/HDPE composites were formed by using the traditional casting method. The physical and electrical properties were investigated for all composites. The results showed that after adding glass powder into the HDPE matrix, the ε<inf>r</inf> value significantly drops due to the inorganic filler suppressed polarization within the systems. For the resistivity, the ρ value significantly increases after adding glass powder to the HDPE matrix for all compositions because this filler promotes the hinder of electric current flow. Finally, it can conclude that the waste glass powder can use as a filler in the HDPE-based composite as better as the commercial SiO<inf>2</inf> powder for the electrical insulting application.
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Frequency Domain Spectroscopy of Pressboard Impregnated with Natural Ester under Thermal Stress
(2022-01-01)
Chumpiboon, K.
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Vittayakorn, W.
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Kittikhuntharadol, Y.
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Maneerot, S.
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Pattanadech, N.
One of the most popular insulating liquids is mineral oil, which is used in many high-voltage apparatuses, especially in transformers. For a few decades, the concept of the use of alternative insulating liquids has been presented. Natural ester is a vegetable-based insulating liquid. Pressboard is a type of electrical insulation paper made of cellulose. Frequency Domain Spectroscopy (FDS) has been used to assess the insulation characteristics such as oil-impregnated paper. In this paper, the FDS of pressboard impregnated with natural ester under thermal stress and pressboard impregnated with natural ester were studied. In the experiment, the pressboard test specimens were heated at 100 degrees Celsius in a vacuum oven for 48 hours to reduce the moisture. Then, the test specimens were impregnated with natural ester for 0, 8, 16, and 24 hours. After that, they were simulated with thermal stress by heating at 150 degrees Celsius in a vacuum oven for 0, 30, and 90 days. To analyze their dielectric integrity, FDS was performed by DIRANA. The test cell for solid insulation testing, according to JIS C2111 was prepared and used for the FDS experiment. The result shows that the characteristics of the natural ester-impregnated pressboard that had been subjected to thermal stress were slightly different when compared with the same impregnation time of the pressboard.
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Modifying Layered Structure of Alkali Titanates via Vibratory Milling Technique
(2021-01-01)
Maluangnont, T.
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Vittayakorn, W.
In this work, the layered structure of lepidocrocite-type alkali titanates was modified via the vibratory milling technique. The Cs<inf>2</inf>Ti<inf>6</inf>O<inf>13</inf>, Cs<inf>0.7</inf>Zn<inf>0.35</inf>Ti<inf>1.65</inf>O<inf>4</inf> and K<inf>0.8</inf>Zn<inf>0.4</inf>Ti<inf>1.6</inf>O<inf>4</inf> systems were prepared by calcining the mixed oxide/(hydrogen)carbonate at 800 °C for 20 h with a heating rate of 10 °C/min and a cooling rate of 20 °C/min. After that, these powders were re-milled by vibratory milling for various times in order to study the effect of post-synthetic mechanical milling to structural modification and interlayer spacing. The phase formation of all powders was determined by using X-ray diffractometer (XRD). Lattice parameters and interlayer spacing of all samples were calculated from XRD peaks. The results showed that the single-phase of lepidocrocite-type Cs<inf>2</inf>Ti<inf>6</inf>O<inf>13</inf> and Cs<inf>0.7</inf>Zn<inf>0.35</inf>Ti<inf>1.65</inf>O<inf>4</inf> was maintained after milling, and the interlayer distance increased by 0.5%. Meanwhile, a mixture of expanded- and original one was observed for K<inf>0.8</inf>Zn<inf>0.4</inf>Ti<inf>1.6</inf>O<inf>4</inf>, with the interlayer expansion up to 1.4%. When compared three systems together which had different interlayer ions and alkali-to-titanium ratio, it was found that the interlayer distances of the Cs<inf>2</inf>Ti<inf>6</inf>O<inf>13</inf> (Cs/Ti = 0.33) and Cs<inf>0.7</inf>Zn<inf>0.35</inf>Ti<inf>1.65</inf>O<inf>4</inf> (Cs/Ti = 0.42) systems were not different because the relatively large Cs ion placed itself at the interlayer position. For the K<inf>0.8</inf>Zn<inf>0.4</inf>Ti<inf>1.6</inf>O<inf>4</inf> system (K/Ti = 0.50), the interlayer distance was much lower than those of the Cs<inf>2</inf>Ti<inf>6</inf>O<inf>13</inf> and Cs<inf>0.7</inf>Zn<inf>0.35</inf>Ti<inf>1.65</inf>O<inf>4</inf> because of the smaller K ion.
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Utilization of Waste Glass Powder as a Filler in Epoxy Resin Based Composite
(2021-01-01)
Buaphuen, P.
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Khunna, D.
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Vittayakorn, W.
This work focuses on the preparation of a high-quality glass powder from broken household waste glass. The expected glass powder prepared from household waste must show a high amount of silicon dioxide with fine particle size. The processing technique used in this work is coarse grinding and high-speed vibratory milling under a variety of conditions to get the best quality of glass powder. The particle size and particle size distribution were examined by using DLS technique. The chemical composition was examined by EDX together with FT-IR and XRF spectroscopies. The morphology of all glass powders was investigated by SEM. The results showed that the wide range of particle size distribution occurred in all milling conditions, which approximately ranged from 1 to 10 µm, and the 4 h-milling time showed the smallest particle size of glass powder. The chemical analysis showed that the glass powder was rich in silica which contained about 67% of SiO<inf>2</inf>. After that, the various ratios of the glass powder/epoxy resin composites were formed by using the traditional casting method. The physical, mechanical and electrical properties were investigated for all composites. The results showed that the H<inf>v</inf> value of the glass powder/epoxy resin composites exhibited a much higher value than that of pure epoxy resin. For the electrical properties, after added 1 wt% of glass powder into the matrix, the ε<inf>r</inf> and R significantly increased. The E<inf>b</inf> value of the composite prepared from waste glass powder showed no significant difference from the composite prepared from commercial SiO<inf>2</inf>. So, it can say that the waste glass powder can be used as a filler in the epoxy resin-based composite as well as the commercial SiO<inf>2</inf> powder for the electrical insulting application.
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Giant suppression of dielectric loss in BaZrO3
(2019-11-01)
Kolodiazhnyi, T.
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Pulphol, P.
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Vittayakorn, W.
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Vittayakorn, N.
We report the effect of precursor's purity and heterovalent substitution on the microstructure and dielectric properties of BaZrO<inf>3</inf> ceramics. We find that independent of the purity or raw materials, the dielectric loss of BaZrO<inf>3</inf> at microwave frequencies is rather high with a Q factor in the range of 1000–3000 at 10 GHz. All stoichiometric ceramics studied show up to three types of low-T dielectric relaxations in the 2–250 K range. All these dielectric anomalies can be suppressed by partial substitution of Zr for Nb. By alloying of BaZrO<inf>3</inf> with a hypothetical BaGa<inf>1/2</inf>Nb<inf>1/2</inf>O<inf>3</inf> phase the Q × f value of ceramics at microwave frequency can be improved significantly. The origin of this remarkable improvement is attributed to the effect of the donor ions on the random electric fields and antiferrodistortive instability. Ceramic with a chemical composition of BaZr<inf>0.96</inf>Ga<inf>0.02</inf>Nb<inf>0.02</inf>O<inf>3</inf> sintered at 1600 °C shows dielectric constant, ε′ = 36.7, temperature coefficient of the resonance frequency, τ<inf>f</inf> = +110 ppm/°C and Q × f = 172 THz.
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Dielectric Properties of Mineral Oil-based Nanofluids using Zinc Oxide Nano-composites for Power Transformer Application
(2018-11-14)
Muangpratoom, P.
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Kunakorn, A.
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Pattanadech, N.
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Vittayakorn, W.
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Thungsook, K.
This research paper describes and analyzes various experiments designed to investigate the dielectric properties (at a series of pre-determined test temperatures and % moisture content) of mineral oil-based nanofluids produced by the incorporation of zinc oxide (ZnO) powder (of mean diameter less than 100nm) into a standard mineral oil, with the surfactant sorbitan mono-oleate (Span 80) added to modify the surface of the nanoparticles in all but the control sample. Five different nanofluid test samples (one control sample and four modified samples) based on the standard mineral oil were produced for testing: 1) a control sample containing no Span 80 and no ZnO, 2) a modified sample with Span 80, and ZnO volume fraction of 0.01 %, 3) a modified sample without Span 80, and ZnO volume fraction of 0.01 %, 4) a modified sample with Span 80, and ZnO volume fraction of 0.03%, and 5) a modified sample without Span 80, and ZnO volume fraction of 0.03 %. In addition, the five liquid samples above were tested to determine AC breakdown voltage at seven different temperatures in the range of 35°C to 90°C. The test circuit was set up in accordance with IEC 60156 using a sphere-sphere electrode configuration with gap spacing of 2.5 mm. Several significant results were obtained from the investigation. Firstly, ZnO nanoparticles had a positive effect on all the test solutions in which they were used. Second, a positive relationship was confirmed between breakdown voltages, temperature rise. Third, a negative correlation was established between higher concentration of ZnO nanoparticles and breakdown voltage. Fourth, the use of surfactant proved to have both positive and negative effects on breakdown voltages.
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Effect of different temperatures on AC breakdown voltage of mineral oil based nanofluids
(2018-07-02)
Muangpratoom, P.
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Kunakorn, A.
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Pattanadech, N.
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Vittayakorn, W.
This study seeks to make improvements in the dielectric properties of transformer oil through the application of nanotechnology. In particular, two nanoparticles are examined experimentally: titanium dioxide (TiO<inf>2</inf>), and barium titanate (BaTiO<inf>3</inf>). Each has a mean diameter not exceeding 100 nm. The nanofluid samples comprised the nanoparticles mixed into the mineral oil through differing procedures. In the first case, the transformer oil was combined with 0.01% volume fraction of the nanoparticle; the second sample used 0.03% volume fraction of the nanoparticle volume fraction. A magnetic stirrer was then used for sample dispersal before an ultrasonic dispersant method was used on the prepared nanofluids so that sample homogeneity could be assured. The experimental process then recorded the AC breakdown voltage characteristics for the liquids through a range of temperatures from 35°C up to 90°C. The findings indicate that the AC breakdown voltages for mineral oils containing nanoparticles exceed those for unmodified mineral oils.

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