Sakon Nakhon, Thailand

Sakon Nakhon Rajabhat University
Sakon Nakhon, Thailand
Time filter
Source Type

Kumharn W.,Sakon Nakhon Rajabhat University
Atmospheric Environment | Year: 2016

This study investigated the values of Angstrom parameters (α,β) in ultraviolet (UV) ranges by using AERONET Aerosol Optical Depth (AOD) data. A second-order polynomial was applied to the AERONET data in order to extrapolate to 320 nm from 2003 to 2013 at seven sites in Thailand. The α,β were derived by applying the Volz Method (VM) and Linear Method (LM) at 320–380 nm at seven monitoring sites in Thailand. Aerosol particles were categorized in both coarse and fine modes, depending on regions. Aerosol loadings were related to dry weather, forest fires, sea salt and most importantly, biomass burning in the North, and South of Thailand. Aerosol particles in the Central region contain coarse and fine modes, mainly emitted from vehicles. The β values obtained were associated with turbid and very turbid skies in Northern and Central regions except Bangkok, while β results are associated with clean skies in South. Higher values of the β at all sites were found in the winter and summer compared with the rainy season, in contrast to South where the highest AOD was observed in June. The β values were likely to increase during 2003–2013. These values correlate with worsening health situations as evident from increasing respiratory diseases reported. © 2016 Elsevier Ltd

Kumharn W.,Sakon Nakhon Rajabhat University
Advances in Space Research | Year: 2014

Ozone (O3) and sulfur dioxide (SO2) in a vertical column of the atmosphere in Thailand were obtained from the Brewers#121 and #120. There are similarities between the O3 patterns obtained from the two sites, which are higher in the summer and rainy season compared with winter, although the magnitude of the change in Bangkok is greater than that in Songkhla. SO2 values showed the summer months provide the higher SO2 values in Bangkok, in contrast to Songkhla where the summer months give lower SO2 values. © 2014 COSPAR. Published by Elsevier Ltd. All rights reserved.

Kumharn W.,Sakon Nakhon Rajabhat University | Rimmer J.S.,University of Manchester | Smedley A.R.D.,University of Manchester | Webb A.R.,University of Manchester
Journal of Atmospheric and Oceanic Technology | Year: 2012

Aerosols play an important role in attenuating solar radiation reaching the earth's surface and are thus important inputs to climate models. Aerosol optical depth is routinely measured in the visible range but little data in the ultraviolet (UV) are available. In the UV range it can be determined from Langley plots of directsun measurements from the Brewer spectrophotometer (where conditions allow) and can also be determined as the residual once the ozone and sulfur dioxide have been accounted for in the extinction observed during a normal Brewer direct-sun measurement. By comparing aerosol optical depth derived from Brewer directsun data in both the United Kingdom and Malaysia, two very different locations, it is determined that while most of the existing global Brewer network could contribute to aerosol optical depth data, further analysis, such as calculation of the Å ngström parameter, would be dependent on latitude and sky conditions. © 2012 American Meteorological Society.

Ruttanapun C.,King Mongkut's University of Technology Thonburi | Wichainchai A.,King Mongkut's University of Technology Thonburi | Prachamon W.,Ubon Ratchathani University | Yangthaisong A.,Ubon Ratchathani University | And 2 more authors.
Journal of Alloys and Compounds | Year: 2011

The samples of Cu1-xPtxFeO2 (0 ≤ x ≤ 0.05) delafossite were synthesized by solid state reaction method for studying thermoelectric properties. The properties of Seebeck coefficient, electrical conductivity and thermal conductivity were measured in the high temperature ranging from 300 to 960 K. The results of Seebeck coefficient, electrical conductivity and power factor were increased with increasing Pt substitution and temperature. The thermal conductivity was decreased from 5.8 to 3.5 W/mK with increasing the temperature from 300 to 960 K. An important results, the highest value of power factor and ZT is 2.0 × 10-4 W/mK2 and 0.05, respectively, for x = 0.05 at 960 K. © 2011 Elsevier B.V. All rights reserved.

Seetawan T.,Sakon Nakhon Rajabhat University | Wattanasarn H.,Sakon Nakhon Rajabhat University
Procedia Engineering | Year: 2012

We report first principle simulation mechanical properties of PbS, PbSe, CdTe and PbTe semiconductors with the rocksalt structure at temperature range 300-700 K by molecular dynamics (MD). The MD simulation has been applied the temperature pressure and volume influence interatomic interaction by Lenard-Jone formula and atoms vacancy. The equations of atoms motion were used time integration by Verlet's algorithm and the interation of long range Coulomb by Ewald's summation. The potential parameter was based on Busing-Ida function contribution thermodynamics equilibrium which ignored phase transition with the cluster atoms site 4×4×4 on 512 atoms (256 cations and 256 anions). The mechanical properties of stress, strain, compressibility, Young's modulus, shear modulus and bulk modulus dependence on temperature were analyzed. © 2010 Published by Elsevier Ltd.

Phaga P.,Sakon Nakhon Rajabhat University | Vora-Ud A.,Sakon Nakhon Rajabhat University | Seetawan T.,Sakon Nakhon Rajabhat University
Procedia Engineering | Year: 2012

The low cost thermoelectric generator (LCTEG) and high performance are investigated. We have investigated a new compound and manufactured locally based area to reduce costs of production. The thermoelectric power generation composed of small n-type (n-CaMnO3) and p-type (p-Ca 3Co4O9) of 31 couples/ in2 and the use of thin copper plate and silver paint as electrodes. It was found that the mean voltage is ∼121.7 mV, current is ∼0.0121mA, power is ∼1.47 μW. © 2010 Published by Elsevier Ltd.

Seetawan T.,Sakon Nakhon Rajabhat University
Key Engineering Materials | Year: 2016

The thermoelectric effects in oxide materials are developed to the Seebeck effect for thermal sensing. Thermal sensors are the thermal converters, in which an electrical, magnetic, mechanical, radiation, chemical signal are measured by converting it into heat and measuring the resulting temperature changes in the device. This proposes an analysis the electrical converters and radiation sensors by using single-junction of p-Ca3Co4O9 and n-CaMnO3 materials are presented into possible thermal sensing. Several thermal converters are measured the signal electrical resistivity, and Seebeck coefficient depended on temperature. Thermal radiation sensors are included the sensitivity, electricity, and specific detectivity. For application, thermoelectric oxide cell can be fabricated crowbar circuit for protection an overvoltage condition of a power supply which it yield 1.2 s turn off switch. © 2016 Trans Tech Publications, Switzerland.

Thanwised P.,Khon Kaen University | Thanwised P.,Sakon Nakhon Rajabhat University | Wirojanagud W.,Khon Kaen University | Reungsang A.,Khon Kaen University
International Journal of Hydrogen Energy | Year: 2012

This study evaluated hydrogen production and chemical oxygen demand removal (COD removal) from tapioca wastewater using anaerobic mixed cultures in anaerobic baffled reactor (ABR). The ABR was conducted based on the optimum condition obtained from the batch experiment, i.e. 2.25 g/L of FeSO 4 and initial pH of 9.0. The effects of the varying hydraulic retention times (HRT: 24, 18, 12, 6 and 3 h) on hydrogen production and COD removal in a continuous ABR were operated at room temperature (32.3 ± 1.5 °C). Hydrogen production rate (HPR) increased with a reduction in HRT i.e. from 164.45 ± 4.14 mL H 2/L.d (24 h HRT) to 883.19 ± 7.89 mL H 2/L.d (6 h HRT) then decreased to 748.54 ± 13.84 mL H 2/L.d (3 h HRT). COD removal increased with reduction in HRT i.e. from 14.02 ± 0.58% (24 h HRT) to 29.30 ± 0.84% (6 h HRT) then decreased to 21.97 ± 0.94% (3 h HRT). HRT of 6 h was the optimum condition for ABR operation as indicated. © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Seetawan T.,Sakon Nakhon Rajabhat University
Applied Mechanics and Materials | Year: 2012

Low cost thermoelectric power generator (LTPG) used for generating electrical voltage, current and power is by designed and fabricated n-type CaMnO 3 and p-type Ca 3Co 4O 9 segments based oxide thermoelectric materials, ceramic substrates and copper electrodes. It was found that the thermoelectric generator 1 in 2 has contact resistance of ∼ 200 Ω voltage ∼ 0.2 V, current ∼ 0.4 mA, power of ∼ 0.1 mW and a conversion efficiency of ∼ 0.78 % in the test performed at differential temperature < 200 K. © (2012) Trans Tech Publications, Switzerland.

Seetawan T.,Sakon Nakhon Rajabhat University
Integrated Ferroelectrics | Year: 2014

The crystal structure and electronic structure of Ca0.8M 0.2MnO3 (M = Cu, Ag, and Bi) materials were simulated by DV-Xα method and Maxwell-Boltzmann distribution to evaluate the electrical resistivity and Seebeck coefficient. The lattice thermal conductivity was calculated by the classical molecular dynamics (MD) method. I was found that the crystal structure of these materials based on a framework of corner-sharing orthorhombic system. The Seebeck coefficient of materials increases with temperature. The electrical resistivity and thermal conductivity decreases with temperature and substituted metal for Ca site. The Ca0.8Bi 0.2MnO3 exhibited better thermoelectric performance and clearly showed concurrence between theoretical analysis and experimental data. © 2014 Taylor & Francis Group, LLC.

Loading Sakon Nakhon Rajabhat University collaborators
Loading Sakon Nakhon Rajabhat University collaborators