Thepsatri Rajabhat University

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Thongkanluang T.,Suratthani Rajabhat University | Kittiauchawal T.,Thepsatri Rajabhat University | Limsuwan P.,King Mongkut's University of Technology Thonburi
Ceramics International | Year: 2011

Green pigments with high near infrared reflectance based on a Cr 2O3-TiO2-Al2O3-V 2O5 composition have been synthesized. Cr 2O3 was used as the host component and mixtures of TiO2, Al2O3 and V2O5 were used as the guest components. TiO2, Al2O3, and V2O5 were mixed into 39 different compositions. The spectral reflectance and the distribution of pigment powder were determined using a spectrophotometer and a scanning electron microscope, respectively. It was found that a pigment powder sample S9 with a Cr2O 3-TiO2-Al2O3-V2O 5 composition of 80, 4, 14 and 2 wt%, respectively, gives a maximum near infrared solar reflectance of 82.8% compared with 49.0% for pure Cr 2O3. The dispersion of pigment powders in a ceramic glaze was also studied. The results show that the pigment powder sample S9 is suitable for use as a coating material for ceramic-based roofs.


Jaikla W.,King Mongkut's University of Technology Thonburi | Noppakarn A.,Thonburi University | Lawanwisut S.,Thepsatri Rajabhat University
Radioengineering | Year: 2012

New first order allpass filter (APF) in current mode, constructed from 2 CCCCTAs and grounded capacitor, is presented. The current gain and phase shift can be electronically/orthogonally controlled. Low input and high output impedances are achieved which make the circuit to be easily cascaded to the current-mode circuit without additional current buffers. The operation of the proposed filter has been verified through simulation results which confirm the theoretical analysis. The application example as current-mode quadrature oscillator with noninteractive current control for both of oscillation condition and oscillation frequency is included to show the usability of the proposed filter.


Jaikla W.,King Mongkut's University of Technology Thonburi | Lawanwisut S.,Thepsatri Rajabhat University | Siripruchyanun M.,King Mongkut's University of Technology Bangkok | Prommee P.,King Mongkut's University of Technology Thonburi
2012 35th International Conference on Telecommunications and Signal Processing, TSP 2012 - Proceedings | Year: 2012

This article presents a four-inputs single output biquadratic filter performing completely standard functions: low-pass, high-pass, band-pass, band-reject and all-pass functions, based on single current controlled current follower transconductance amplifier (CCCFTA). The features of the circuit are that; the quality factor and natural frequency can be tuned electronically via the input bias current; the circuit description is very simple, consisting of merely 1 CCCFTA and 2 grounded capacitors; the filter does not require inverting-type input current signal. Additionally, each function response can be selected by suitably selecting input signals with digital method. Using only single active element and grounded capacitors, the proposed circuit is very suitable to further develop into an integrated circuit. The PSPICE simulation results are depicted. The given results agree well with the theoretical anticipation. © 2012 IEEE.


Saripan A.F.,Thepsatri Rajabhat University | Reungsang A.,Khon Kaen University
International Journal of Hydrogen Energy | Year: 2013

Thermophilic hydrogen production from xylan by Thermoanaerobacterium thermosaccharolyticum KKU-ED1 isolated from elephant dung was investigated using batch fermentation. The optimum conditions for hydrogen production from xylan by the strain KKU-ED1 were an initial pH of 7.0, temperature of 55 °C and xylan concentration of 15 g/L. Under the optimum conditions, the hydrogen yield (HY), hydrogen production rate (HPR) and xylanase activity were 120.05 ± 15.07 mL H2/g xylan, 11.53 ± 0.19 mL H2/L h and 0.41 units/mL, respectively. The optimum conditions were then used to produce hydrogen from 62.5 g/L sugarcane bagasse (SCB) (equivalent to 15 g/L xylan) in which the HY and HPR of 1.39 ± 0.10 mL H2/g SCB (5.77 ± 0.41 mL H2/g xylan) and 0.66 ± 0.04 mL H2/L h, respectively, were achieved. In comparison to the other strains, the HY of the strain KKU-ED1 (120.05 ± 15.07 mL H2/g xylan) was close to that of Clostridium sp. strain X53 (125.40 mL H2/g xylan) and Clostridium butyricum CGS5 (90.70 mL H2/g xylan hydrolysate). Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Saripan A.F.,Thepsatri Rajabhat University | Saripan A.F.,Khon Kaen University | Reungsang A.,Khon Kaen University
International Journal of Hydrogen Energy | Year: 2014

The objective of this study was to optimize the culture conditions for simultaneous saccharification and fermentation (SSF) of cellulose for bio-hydrogen production by anaerobic mixed cultures in elephant dung under thermophilic temperature. Carboxymethyl cellulose (CMC) was used as the model substrate. The investigated parameters included initial pH, temperature and substrate concentration. The experimental results showed that maximum hydrogen yield (HY) and hydrogen production rate (HPR) of 7.22 ± 0.62 mmol H 2/g CMCadded and 73.4 ± 3.8 mL H2/L h, respectively, were achieved at an initial pH of 7.0, temperature of 55 °C and CMC concentration of 0.25 g/L. The optimum conditions were then used to produce hydrogen from the cellulose fraction of sugarcane bagasse (SCB) at a concentration of 0.40 g/L (equivalent to 0.25 g/L cellulose) in which an HY of 7.10 ± 3.22 mmol H2/g celluloseadded. The pre-dominant hydrogen producers analyzed by polymerase chain reaction-denaturing gel gradient electrophoresis (PCR-DGGE) were Thermoanaerobacterium thermosaccharolyticum and Clostridium sp. The lower HY obtained when the cellulose fraction of SCB was used as the substrate might be due to the presence of lignin in the SCB as well as the presence of Lactobacillus parabuchneri and Lactobacillus rhamnosus in the hydrogen fermentation broth. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Saripan A.F.,Thepsatri Rajabhat University | Reungsang A.,Khon Kaen University
International Journal of Green Energy | Year: 2015

Thermophilic bio-hydrogen production from xylan by anaerobic mixed cultures in elephant dung was conducted. The initial pH, temperature, and xylan concentration of 7.0, 55°C and 3.0 g/L, respectively, gave a respective maximum hydrogen yield (HY) and hydrogen production rate (HPR) of 12.16 mmol H2/g xylan and 61.30 mL H2/L.d. The optimum conditions were used to produce hydrogen from sugarcane bagasse (SCB) in which an HY of 2.60 mmol H2/g SCB and a HPR of 59.78 mL H2/L.d were obtained. The hydrogen producers present in both xylan and SCB fermentation broth were Thermoanaerobacterium thermosaccharolyticum and Clostridium sp. Copyright © 2015 Taylor & Francis Group, LLC.


Saripan A.F.,Thepsatri Rajabhat University | Reungsang A.,Khon Kaen University
Electronic Journal of Biotechnology | Year: 2013

Background: Biological hydrogen production by microorganisms can be divided into two main categories i.e. photosynthetic organisms that produce hydrogen using light as energy source and anaerobic bacteria that produce hydrogen via dark fermentation. Dark fermentative hydrogen production by anaerobic bacteria has the advantages of a higher HPR without illumination and of the capability to convert various kinds of substrate. Results: Thermophilic hydrogen producer was isolated from elephant dung and identified as Thermoanaerobacterium thermosaccharolyticum KKU-ED1 by 16S rRNA gene analysis, which was further used to produce hydrogen from mixed pentose sugar i.e., xylose/arabinose. The optimum conditions for hydrogen production from mixed xylose/arabinose by KKU-ED1 were a 1:1 xylose/arabinose mixture at the total concentration of 5 g/L, initial pH of 6.5 and temperature of 55°C. Under the optimum conditions, hydrogen from sugar derived from acid-hydrolyzed sugarcane bagasse at a reducing sugar concentration were achieved. Soluble metabolite product (SMP) was predominantly acetic acid indicating the acetate-type fermentation. Conclusions: The strain KKU-ED1 appeared to be a suitable candidate for thermophilic fermentative hydrogen production from hemicellulosic fraction of lignocellulosic materials due to its ability to use various types of carbon sources. © 2013 by Pontificia Universidad Católica de Valparaíso, Chile.


Fangkum A.,Thepsatri Rajabhat University | Fangkum A.,Khon Kaen University | Reungsang A.,Khon Kaen University
International Journal of Hydrogen Energy | Year: 2011

Biohydrogen production by batch fermentation of mixed xylose/arabinose at thermophilic temperature using anaerobic mixed cultures in elephant dung as the seed inoculums was investigated. Elephant dung was heat-treated in boiling water for 2 h before used as the seed inoculum in order to inhibit methanogenic activity. Biohydrogen was successfully produced from mixed xylose/arabinose. The optimum conditions for hydrogen production were the initial concentration of mixed xylose/arabinose 5 g/L each, initial cultivation pH 5.5 and temperature 55 °C. Under the optimum conditions, a maximum hydrogen yield of 2.49 mol-H2/mol-sugar consumed was obtained. The optimum conditions were then used to produce hydrogen from sugar derived from acid-hydrolysed sugarcane bagasse (SCB) at a reducing sugar concentration of 10 g/L in which a lower hydrogen yield of 1.48 mol-H2/mol-sugar consumed was achieved. Main soluble product was acetate suggesting the hydrogen fermentation from mixed xylose/arabinose is the acetate type. The dominant hydrogen producers found in both fermentation broth were Thermoanaerobacterium thermosaccharolyticum and Clostridium sp. Lower hydrogen yield in the SCB hydrolysate fermentation broth may be due to the present of Clostridium ragsdalei and microorganisms in the class Bacilli viz. Lactococus lactis subsp., Lactobacillus delbrueckii, and Sporolactobacillus sp. as well as the inhibitors (acetic acid and furfural) contained in the SCB hydrolysate. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Lawanwisut S.,Thepsatri Rajabhat University | Siripruchyanun M.,King Mongkut's University of Technology Bangkok
2012 35th International Conference on Telecommunications and Signal Processing, TSP 2012 - Proceedings | Year: 2012

This article reviews a circuit which is active-only floating positive inductance simulator. The floating inductance simulator comprises merely one current controlled current conveyor transconductance amplifier (CCCCTA) and an internally frequency compensated operational amplifier. The simulated inductance value can be controlled electronically by adjusting bias current of the CCCCTA. The circuit performances are depicted through PSpice simulation, they show good agreement to theoretical anticipation. An application as a resonant circuit is included to confirm the usability of proposed circuit. © 2012 IEEE.


Wanichacheva N.,Silpakorn University | Hanmeng O.,Silpakorn University | Hanmeng O.,Thepsatri Rajabhat University | Kraithong S.,Silpakorn University | Sukrat K.,Sudan University of Science and Technology
Journal of Photochemistry and Photobiology A: Chemistry | Year: 2014

A "naked-eye" indicator and fluorescent chemosensor based on fluorescein connected to two rhodamine B fluorophores by hydrazide moieties, RF1, was designed and synthesized for highly sensitive and selective detection of Hg2+. The sensor system operated through the FRET process from the fluorescein energy donor to the ring-opened rhodamine B acceptors. The binding to Hg2+ was observed through both fluorescence enhancement and a chromogenic change (from colorless to pink). The sensor is shown to discriminate various foreign metal ions, particularly Ag+, Pb2+ and Cu2+, as well as Li+, Na+, Mg2+, Cd2+, K+, Al3+, Fe3+, Ca 2+, Ba2+ and Zn2+, with a detection limit of 2.02 × 10-8 M or 4 ppb toward Hg2+. © 2014 Elsevier B.V.

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