Ubon Ratchathani, Thailand

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Srisawatsakul C.,Ubon Ratchathani Rajabhat University
20th International Computer Science and Engineering Conference: Smart Ubiquitos Computing and Knowledge, ICSEC 2016 | Year: 2016

Over the last decade, mobile devices have been widely used in numerous aspects. Thanks to mobile applications platforms that deliver millions of mobile applications for end users anytime and anywhere. Lately, research on mobile devices and mobile applications have been gaining more attention. However, the research to date has tended to focus on technical aspects or adoption behavior of mobile applications. There is still very little scientific understanding on how to measure the level of information in mobile device usage. Therefore, this study demonstrates an approach based on Shannon's entropy for the measurement of the information level and uncertainty in mobile applications usage. The initial findings confirmed that the purposed method could measure the level of information in the mobile device usage. The different number of mobile applications and the frequency of each mobile application usage would generate different bits of entropy values, which mean it can use to indicate the level of information and uncertainty. The results of this paper will serve as indicators for the direction of our planned future research in this field. © 2016 IEEE.

Manwong M.,Ubon Ratchathani University | Songserm N.,Ubon Ratchathani Rajabhat University | Promthet S.,Khon Kaen University | Matsuo K.,Kyushu University
Asian Pacific Journal of Cancer Prevention | Year: 2013

Background: Cholangiocarcinoma (CCA) is the most common cancer in Northeast Thailand. It is also a crucial health problem for Thai people. Various risk factors for CCA have been identified in the upper part of Northeast Thailand, but no similar studies of risk factors have been conducted in the lower parts of the region. This study aimed to investigate factors associated with CCA in the resident population. Materials and Methods: A hospital-based case-control study was conducted during 2009-2012 with the recruitment of 123 CCA cases and 123 non-CCA patient controls, matched for sex, age and residential area. Information was collected by interview with a structured questionnaire. Blood samples were collected for assays of anti-OV antibodies. Associations between various personal factors, dietary habits, family history, the presence of anti-OV antibodies and CCA were analyzed using multiple conditional logistic regression. Results: Patients who consumed raw meat (beef, pork) and alcoholic beverages ≥3 times per week had a higher risk of CCA than non-consumers (ORadj=4.33; 95%CI=1.14-16.35 and ORadj=2.13; 95%CI=1.00-4.55, respectively). Patients who had a family history of cancer had a higher risk than those who did not (ORadj=4.34; 95%CI=1.80-10.43). Also, patients who had anti-OV antibodies (AU>23.337) had a higher risk than those whose anti-OV antibodies were below the cut-off(AU≤23.34) (ORadj=3.09; 95%CI=1.04-9.16). Conclusions: As is the case in the upper part of Northeast Thailand, OV infection is a crucial risk factor for CCA in people who live in lower part of the region. Similarly, a family history of cancer and the consumption of alcohol are risk factors for CCA.

Poopanya P.,Ubon Ratchathani Rajabhat University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2014

Electronic structures and thermoelectric properties of delafossite 2H-CuAlO2 have been theoretically investigated using first principles calculations and Boltzmann transport equation. The delafossite 2H-CuAlO2 exhibits an indirect gap of 2.2 eV and a direct gap of 3.1 eV. As the temperature increases, the electrical conductivity increases but the Seebeck coefficient decreases. However, the power factor tends to increase with temperature and dramatically increases in the case of high carrier concentration when the doping level is located near the valence band. It is also found that the dimensionless figure of merit, ZT, increases with increasing temperature. At T = 680 K, the calculated ZT are 0.007 for p-type doping and 0.0035 for n-type doping. These maximum ZT are obtained at the carrier concentration of approximately 5.0 × 1021 cm- 3 and 1.0 × 1021 cm- 3 for p-type and n-type dopings, respectively. © 2014 Elsevier B.V. All rights reserved.

Tangkawanit S.,Ubon Ratchathani Rajabhat University
Advanced Materials Research | Year: 2013

This research was an intensive study on development of Hibiscus cannabinus L. fibers dyeing with natural dyes. The result reflected that color shade and color strength value results were different depend on type of mordanted. The Hibiscus cannabinus L. washing with detergent dyeing with Caesalpinia sappan L. and various mordented showed that light fastness was in level 3-4, when CuSO4 and FeSO4 mordanted light fastness result was in level 4-5, mordants as lime, CuSO4 and FeSO4 were added washing fastness property was in level 5. © (2013) Trans Tech Publications, Switzerland.

Wetchakun N.,Chiang Mai University | Chainet S.,Chiang Mai University | Phanichphant S.,Chiang Mai University | Wetchakun K.,Ubon Ratchathani Rajabhat University
Ceramics International | Year: 2015

BiVO4/TiO2 nanocomposites were successfully synthesized by coupling the modified sol-gel method with hydrothermal method. The samples were physically characterized X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer, Emmett and Teller (BET)-specific surface area, UV-vis diffuse reflectance spectrophotometry, zeta potential, and photoluminescence techniques. The BiVO4/TiO2 nanocomposites exhibited good photocatalytic activity in degradation of methylene blue under simulated solar light irradiation. The photodegradation of methylene blue demonstrated that 0.5BiVO4/0.5TiO2 photocatalyst exhibited much enhanced photoactivity than pure BiVO4 and TiO2. Based on the obtained results, the as-prepare BiVO4/ TiO2 nanocomposite possessed great adsorptivity of methylene blue, extended light adsorption range, and efficient charge separation properties. Overall, this work could provide new insights into the fabrication of a BiVO4/TiO2 composite as high performance photocatalyst and promise as a solar light photocatalyst for dye wastewater treatment. © 2015 Elsevier Ltd and Techna Group S.r.l.

Poopanya P.,Ubon Ratchathani Rajabhat University | Yangthaisong A.,Ubon Ratchathani University
AIP Conference Proceedings | Year: 2013

We present the calculations of the electronic structure and transport properties on the anti-fluorite Mg2Si using the full potential linearized augmented plane-wave (FP-LAPW) method and the semi-classical Boltzmann theory. The modified Becke-Johnson (mBJ) exchange potentials are used to derive energy gaps and correct band gaps according to experimental values. It is found that Mg2Si is an indirect band gap (Γ→X) material with the gap of 0.56 eV which is in good agreement with the experimental observation. Note that the band structure of Mg2Si is directly used in combination with the semi-classical Boltzmann theory to obtain the transport coefficients. It is found that the material is the n-type semiconductor with the lowest electron concentration of 3.03×10 14 cm-3 at 300 K. We have also calculated the thermoelectric properties of Mg2Si based on the rigid band approximation by varying the p-type and n-type doping levels. At room temperature, the highest power factor for p-type and n-type dopants are obtained at the hole and electron concentration of 1.63×1020 cm -3 and 1.15×1021 cm-3, respectively. From the electronic states, we also found that the n-type doping region is dominated by the Mg-2p6 3s2 and Si-3p2 states, while the Mg-2p6 and Si-3p2 states are important in the p-type doped Mg2Si. © 2013 AIP Publishing LLC.

Wetchakun N.,Chiang Mai University | Incessungvorn B.,Chiang Mai University | Wetchakun K.,Ubon Ratchathani Rajabhat University | Phanichphant S.,Chiang Mai University
Materials Letters | Year: 2012

Titanium dioxide (TiO 2) nanoparticles with different ratios of anatase to rutile transformation were synthesized by the modified sol-gel method. The optical properties were investigated by UV-vis diffuse reflectance spectrophotometry. Phase transformation, crystallinity, and crystal structure of the calcined TiO 2 samples were derived from X-ray diffraction analysis. The morphology and particle size of TiO 2 were characterized by transmission electron microscopy (TEM). The Brunauer, Emmett and Teller (BET) adsorption-desorption of nitrogen gas for specific surface area determination at the temperature of liquid nitrogen was performed on TiO 2 samples. TiO 2 nanoparticles calcined at 400 °C for 3 h possessed the highest specific surface area of 97 m 2 g - 1. The temperature of anatase to rutile transformation was found between 500 and 600 °C, and then completely transformed to rutile phase at 600 °C. Average particle sizes of the nanoparticles were in the range of 10-50 nm at calcination temperature between 400 and 600 °C. At higher temperature clearly favored particles growth and agglomerates are corresponded to decrease specific surface area. © 2012 Published by Elsevier B.V. All rights reserved.

Nakhowong R.,Ubon Ratchathani Rajabhat University
Materials Letters | Year: 2016

Calcium manganese oxide (CaMnO3) nanofibers with diameters ranging from 460 to 520 nm were successfully synthesized for the first time by electrospinning. The fibers were calcined at 700, 800, and 900°C for 2 h in air. The fibers were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD patterns showed crystalline phases of CaMnO3 at 800°C with the perovskite structure. The SEM and TEM images revealed the surface of the CaMnO3 nanofibers as rough, with a porous structure. These results indicated that calcination temperature influenced the morphology and crystalline phase of CaMnO3. © 2015 Published by Elsevier B.V.

Chala S.,Chiang Mai University | Wetchakun K.,Ubon Ratchathani Rajabhat University | Phanichphant S.,Chiang Mai University | Inceesungvorn B.,Chiang Mai University | Wetchakun N.,Chiang Mai University
Journal of Alloys and Compounds | Year: 2014

Pure BiVO4 and nominal 0.5-5.0 mol% Fe-loaded BiVO4 samples were synthesized by hydrothermal method. All samples were characterized in order to obtain the correlation between structure and photocatalytic properties by X-ray diffraction, Brunauer, Emmett and Teller, UV-vis diffuse reflectance spectrophotometry, photoluminescence spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and inductively coupled plasma-optical emission spectroscopy. The structure of all samples was single-phase monoclinic scheelite. The absorption spectrum of 5.0 mol% Fe-loaded BiVO4 shifted to the visible region, suggesting the potential application of this material as a superior visible-light driven photocatalyst in comparison with pure BiVO4. Photocatalytic activities of all photocatalyst samples were examined by studying the degradation of methylene blue under visible light irradiation. The results clearly showed that Fe-loaded BiVO4 sample exhibited remarkably higher activity than pure BiVO 4. © 2014 Elsevier B.V. All rights reserved.

Poopanya P.,Ubon Ratchathani Rajabhat University | Yangthaisong A.,Ubon Ratchathani University
Physica B: Condensed Matter | Year: 2013

The screened exchange local density approximation (sX-LDA) hybrid functional within the pseudopotential plane wave method is performed to improve the electronic structures of cubic BiAlO3 and its thermodynamic properties are investigated using the density functional perturbation theory (DFPT). The equilibrium lattice constant of cubic BiAlO3 is 3.67 Å which is applied to calculate its electronic structures. The calculated sX-LDA electronic structures are compared to standard generalized gradient approximation (GGA) approach. It is found that BiAlO3 is an indirect band gap material at M(1/2,1/2,0)-X(0,0,1/2) point with the gap value of 1.84, and 3.43 eV for GGA, and sX-LDA calculations, respectively. The linear response method is employed in order to calculate the phonon dispersion relations and phonon density of states. The predicted thermodynamic quantities, specific heat and Debye temperature, of cubic perovskite BiAlO3 are also reported. © 2013 Elsevier B.V.

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