Sakulkalavek, Aparporn
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Sakulkalavek, Aparporn
Alternative Name
Sakulkalavek, A.
Sakulkalavek, Aparpron
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Email
aparporn.sa@kmitl.ac.th
30 results
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Item type:Publication, A simplified and powerful image processing methods to separate Thai jasmine rice and sticky rice varieties(2018-01-01); Suwansukho, KajpanyaA simplified and powerful image processing procedures to separate the paddy of KHAW DOK MALI 105 or Thai jasmine rice and the paddy of sticky rice RD6 varieties were proposed. The procedures consist of image thresholding, image chain coding and curve fitting using polynomial function. From the fitting, three parameters of each variety, perimeters, area, and eccentricity, were calculated. Finally, the overall parameters were determined by using principal component analysis. The result shown that these procedures can be significantly separate both varieties. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Enhanced hydrophilicity for TiO2 nanotube array by simultaneous nitrogen plasma and thermal annealing treatments(2018-09-05); In this work, highly ordered TiO<inf>2</inf> nanotube (TNTs) array was fabricated by electrochemical anodization technique on titanium sheet. Simultaneous N<inf>2</inf> plasma and thermal annealing process were employed on TNTs using different N<inf>2</inf> gas flow rates at 500°C. As-anodized and N<inf>2</inf> plasma TNTs were characterized for their microstructure, surface elemental composition, and wettability by scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and contact angle measurement, respectively. It was found that N<inf>2</inf> plasma and thermal annealing treatments affect to the change of crystal structure, surface chemistry and wettability of TNTs. The N<inf>2</inf> plasma TNTs exhibits anatase phase with the orientations of (101) and (200). XPS spectra show that the nitrogen atom from plasma was introduced into the surface of TNTs and depends on the N<inf>2</inf> gas flow rates. From contact angle measurement, it can be observed the improvement of wettability (hydrophilicity) of the TNTs due to the N-doped TiO<inf>2</inf> nanotube after N<inf>2</inf> plasma and thermal annealing treatments. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Enhancing the electrical conductivity and thermoelectric figure of merit of the p-type delafossite CuAlO2 by Ag2O addition(2017-10-01); (CuAlO<inf>2</inf>)<inf>1-x</inf>(Ag<inf>2</inf>O)<inf>x</inf> specimens with 0 ≤ x ≤ 0.06 were prepared through the sintering of mixtures of CuO, Al<inf>2</inf>O<inf>3</inf> and Ag<inf>2</inf>O powders at 1373 K. Hall effect, Seebeck coefficient and electrical conductivity measurements were subsequently employed to assess the electrical transport properties. The electrical conductivity of the as-sintered samples was found to increase with Ag<inf>2</inf>O addition as a result of increases in the carrier density. Over the temperature range of 323–623 K, the transport properties can be attributed to thermally activated transitions from the acceptor state to the valence band. In contrast, the variable range hopping theory is applicable over the temperature range of 623–873 K. Ag<inf>2</inf>O addition evidently reduces the defect binding energy in the electronic structure of the CuAlO<inf>2</inf>. The addition of this compound also obstructs the formation of both a spinel phase and CuO, such that the oxygen off-stoichiometry value and the carrier density are increased with increasing Ag<inf>2</inf>O levels. The presence of Ag metal has the main effect on thermal conductivity below 400 K, while above 400 K increases in the phonon concentration affect the conductivity. The highest value obtained for the figure of merit was 0.0044 at 573 K, from a sample containing 0.2 at.% Ag<inf>2</inf>O. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Optimum sintering temperature for thermoelectric properties of low-cost CuAl0.90Fe0.10O2 material(2016-10-01); Sintering temperature is a key parameter that affects thermoelectric properties. In this study, a suitable temperature to synthesize thermoelectric properties of low-cost delafossite CuAl<inf>0.90</inf>Fe<inf>0.10</inf>O<inf>2</inf> was investigated through the sintering of CuO, Al<inf>2</inf>O<inf>3</inf> and Fe<inf>2</inf>O<inf>3</inf> mixed powder at 1333, 1423 and 1473 K. The optimum sintering temperature is at 1333 K, where the single-phase CuAlO<inf>2</inf> and the highest dimensionless figure of merit of 0.014 at the measured temperature of 873 K were observed. CuAlO<inf>2</inf> with trace amounts of CuO, and CuAl<inf>2</inf>O<inf>4</inf> and CuO were found at the sintering temperature of 1423 and 1473 K, respectively. The highest Seebeck coefficient and thermal conductivity was at the sintering temperature of 1473 K, with the maximum electrical conductivity and power factor at the measured temperature of 873 K of 5.7 Ω<sup>−1</sup> cm<sup>−1</sup> and 9.81 × 10<sup>−5</sup> Wm<sup>−1</sup> K<sup>−2</sup>, respectively. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Figures of merit of low-cost CuAl0.9Fe0.1O2 thermoelectric material prepared at different solid state reaction sintering temperatures(2015-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Achieving thermoelectric improvement through the addition of a small amount of graphene to CuAlO2 synthesized by solid-state reaction(2018-07-15); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Method of high active preparation and electrical properties of CuFeO2 delafossite-type(2014-01-01); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effect of real working environment/formation of oxide phase on thermoelectric properties of flexible Sb2Te3 films(2019-09-01); ; Flexible Sb<inf>2</inf>Te<inf>3</inf> thin films, for thermoelectric generator applications, were deposited by DC magnetron sputtering. As-deposited films were annealed in air to simulated a realistic operating environment. The oxidation behavior of the films was studied by monitoring their phase change on exposure to air at different temperatures between 50 and 300 °C for annealing times from 1 to 15 h. Oxidation of Sb and Te formed Sb<inf>2</inf>Te<inf>4</inf> and TeO<inf>2</inf> phases when annealing above 100 °C and Sb<inf>2</inf>Te<inf>3</inf> decomposed into oxide phases at an annealing temperature of 250 °C for 15 h. The thermoelectric performance decreased as the content of Sb<inf>2</inf>O<inf>4</inf> and TeO<inf>2</inf> phases increased. These findings show the limitations of Sb<inf>2</inf>Te<inf>3</inf> films operating in air without vacuum or a protective environment. We propose that the kinetic growth of oxide formation on the Sb<inf>2</inf>Te<inf>3</inf> thin films depend on chemical activation energy and oxygen diffusion through the oxide barrier by the variation of annealing temperature and annealing time, respectively. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Changes in structural, morphological, and corrosion properties of CrN thin film effected by varying N2 pressure In the sputtering process(2015-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Empirical modelling and optimization of pre-heat temperature and Ar flow rate using response surface methodology for stoichiometric Sb2Te3 thin films prepared by RF magnetron sputtering(2017-01-01); In this work, a flexible antimony telluride thin film was deposited by RF magnetron sputtering. The response surface methodology based on central composite design was used to study the influence of the Ar flow rate (A) and the pre-heat temperature of the substrate (T) on the Te content (%Te). The %Te of the thin film tended to increase with an increase in both the Ar flow rate and the pre-heat temperature. Stoichiometric Sb<inf>2</inf>Te<inf>3</inf> thin films were obtained that agreed with the model equation of %Te = 59.22 + 0.070 A - 0.098 T + 5.580 × 10<sup>−4</sup>AT – 7.212 × 10<sup>−4</sup>A<sup>2</sup> + 1.05 × 10<sup>−4</sup> T<sup>2</sup>. Micro-strainand dislocation density were enhanced using high Ar flow rate and low pre-heat temperature. The dislocation density and stoichiometry contributed to the substantially enhanced Seebeck coefficient and electrical conductivity of the films, respectively. The temperature dependence of the power factor is strongly dominated by electrical conductivity, leading to the highest value for a stoichiometric film of 2.0 × 0<sup>−3</sup> W/m.K<sup>2</sup> at 250 °C. During process optimization, several conditions can be prepared by RF magnetron sputtering with an Sb<inf>2</inf>Te<inf>3</inf> target in order to obtain stoichiometric Sb<inf>2</inf>Te<inf>3</inf> films. However, the expected condition to obtain highest power factor was the highest Ar gas flow rate and the lowest pre-heat temperature.