(Received March 30, 2004; accepted September 3, 2004; published July 8, 2005) A simple, fast and ... more (Received March 30, 2004; accepted September 3, 2004; published July 8, 2005) A simple, fast and accurate technique employing an open-ended coaxial sensor for the determination of the moisture content in oil palm fruit is presented. For this technique, a calibration equation ...
In the present study, binary oxide (cadmium oxide [CdO])x (zinc oxide [ZnO])1-x nanoparticles (NP... more In the present study, binary oxide (cadmium oxide [CdO])x (zinc oxide [ZnO])1-x nanoparticles (NPs) at different concentrations of precursor in calcination temperature were prepared using thermal treatment technique. Cadmium and zinc nitrates (source of cadmium and zinc) with polyvinylpyrrolidone (capping agent) have been used to prepare (CdO)x (ZnO)1-x NPs samples. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy, energy-dispersive X-ray (EDX), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. XRD patterns analysis revealed that NPs were formed after calcination, which showed a cubic and hexagonal crystalline structure of (CdO)x (ZnO)1-x NPs. The phase analysis using EDX spectroscopy and FTIR spectroscopy confirmed the presence of Cd and Zn as the original compounds of prepared (CdO)x (ZnO)1-x NP samples. The average particle size of the samples increased from 14 to 33 nm as the concentration of precurso...
In this study we have synthesized polyaniline/CoFe2O4 nanocomposites (PANI@CFs) by in situ polyme... more In this study we have synthesized polyaniline/CoFe2O4 nanocomposites (PANI@CFs) by in situ polymerization method with different amounts of the CoFe2O4 nanoparticles NPs (CF-NPs) (0.5 g and 1.0 g). The structural optical, thermal and dielectric properties of the as synthesized PANI@CFs were studied. The XRD analysis ensures that CF-NPs have a single phase spinel structure. The XRD and EDAX results confirmed that the CF-NPs were successfully incorporated in the PANI matrix. The crystalline size analysis revealed that the size increased with increasing CF-NPs amount in the PANI@CFs, because of the aggregation effect. TGA exhibited an enhanced thermal stability of the PANI@CFs as compare with PANI owing to the strong interaction between the CF-NPs and polymer matrix. The energy band gaps as calculated through the Tauc relation were found to be gradually higher with the increasing the amount of CF-NPs in PANI@CFs. The dielectric constants (ε', ε″), dielectric loss (tanδ) and AC conductivity (σac) were studied as the function of frequency and composition, which have been explained by 'Maxwell Wagner Model'. The high dielectric constant and ac conductivity were observed of PANI@CFs than PANI. Moreover, PANI@CF 1:2 exhibited the promising photocatalytic activity for the photo-decoloration of the methyl orange (MO) dye under UV light irradiation. Results also showed protection of photo-decoloration of the MO dye by the disodium ethylenediaminetetraacetate dehydrate (EDTA-Na2; C10H14N2Na2O8·2H2O) (hole scavenger) and tert-butyl alcohol (C4H10O) (radical scavenger) clearly suggested the implication of reactive oxygen species (ROS) in the photocatalytic activity of PANI@CF 1:2. It is encouraging to conclude that PANI@CF bears the potential of its applications in photocatalysis.
The effect of Ba-substitution at Sr site on the structure, magnetoresistance and magnetic propert... more The effect of Ba-substitution at Sr site on the structure, magnetoresistance and magnetic properties of La0.67(Sr1−xBax)0.33MnO3 samples with x = 0.00, 0.25, 0.50, 0.75 and 1.00 has been investigated. Single phase samples were obtained by a conventional solid state reaction method with rhombohedral (x = 0.00) and orthorombic (x = 1.00) structure. The grain size increases with Ba content. Low field magnetoresistance phenomenon at low temperature can be observed for all samples. However it vanishes at 300 K for x = 0.75 and 1.00. The variation of MR% value is small ranging between 16 to 18% at 100 K in an applied field of 1 T. All samples show a single magnetic transition from the ferromagnetic (FM) state to the paramagnetic (PM) state as the temperature increases. Curie temperature, Tc decrease with increasing Ba concentration.
... Microstructure of Pr0.67Ba0.33MnO3 Ceramic WONG JEN KUEN 1, a , LIM KEAN PAH 1, b , ABDUL HAL... more ... Microstructure of Pr0.67Ba0.33MnO3 Ceramic WONG JEN KUEN 1, a , LIM KEAN PAH 1, b , ABDUL HALIM SHAARI 1, c , CHEN SOO KIEN 1, d and NG SIAU WEI 1, e ... 122 (2002), p. 266-271. [11] HY Hwang, SW. Cheong, NP Ong and B. Batlogg: Phys. Rev. Lett. Vol. ...
Photopyroelectric spectroscopy is used to study the band-gap energy of the ceramic (ZnO + xSb{2}O... more Photopyroelectric spectroscopy is used to study the band-gap energy of the ceramic (ZnO + xSb{2}O{3}), x = 0.1 - 1.5 mol% and the ceramic (ZnO + 0.4 mol% Bi{2}O{3} + xSb{2}O{3}), x = 0 - 1.5 mol% sintered at isothermal temperature, 1280 °C, for 1 and 2 hours. The wavelength of incident light, modulated at 9 Hz, is kept in the visible range and the photopyroelectric spectrum with reference to doping level is discussed. The band-gap energy is reduced from 3.2 eV, for pure ZnO, to 2.86, 2.83 eV for the samples without Bi{2}O{3}at 0.1 mol% of Sb{2}O{3} for 1 and 2 hours of sintering time, respectively. It is reduced to 2.83, 2.80 eV for the samples with Bi{2}O{3} at 0 mol% of Sb{2}O{3} for 1 and 2 hours of sintering time, respectively. The steepness factor σ A which characterizes the slop of exponential optical absorption is discussed with reference to the doping level. The phase constitution is determined by XRD analysis; microstructure and compositional analysis of the selected areas are analyzed using SEM and EDX.
Thermal diffusivity measurement of the Bi-Pb-Sr-Ca-CII-O superconducting ceramic sample is report... more Thermal diffusivity measurement of the Bi-Pb-Sr-Ca-CII-O superconducting ceramic sample is reported. In this work camera flash and polyvinylidene difluoride (PVDF) film were respectively used as heating source and pyroelectric detector. The theoretical signal calculation based on Dirac-function approximation for camera flash temporal profile was used to deduce the thermal diffusivity. The measurement was done from 85 K to room temperature. The thermal diffusivity curve shows a dip at the resistive transition onset ...
... Practical samples usually are of finite size, where the sample thickness, L is ≤ 5s. Hence, t... more ... Practical samples usually are of finite size, where the sample thickness, L is ≤ 5s. Hence, the correction factors derived by Valdes [14] as shown in equation (2) is consider. ∑ ∞ = ... The pressure in the chamber was reduced to ≈ 10-3 torr by using a rotary vane pump. ...
(Received March 30, 2004; accepted September 3, 2004; published July 8, 2005) A simple, fast and ... more (Received March 30, 2004; accepted September 3, 2004; published July 8, 2005) A simple, fast and accurate technique employing an open-ended coaxial sensor for the determination of the moisture content in oil palm fruit is presented. For this technique, a calibration equation ...
In the present study, binary oxide (cadmium oxide [CdO])x (zinc oxide [ZnO])1-x nanoparticles (NP... more In the present study, binary oxide (cadmium oxide [CdO])x (zinc oxide [ZnO])1-x nanoparticles (NPs) at different concentrations of precursor in calcination temperature were prepared using thermal treatment technique. Cadmium and zinc nitrates (source of cadmium and zinc) with polyvinylpyrrolidone (capping agent) have been used to prepare (CdO)x (ZnO)1-x NPs samples. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy, energy-dispersive X-ray (EDX), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. XRD patterns analysis revealed that NPs were formed after calcination, which showed a cubic and hexagonal crystalline structure of (CdO)x (ZnO)1-x NPs. The phase analysis using EDX spectroscopy and FTIR spectroscopy confirmed the presence of Cd and Zn as the original compounds of prepared (CdO)x (ZnO)1-x NP samples. The average particle size of the samples increased from 14 to 33 nm as the concentration of precurso...
In this study we have synthesized polyaniline/CoFe2O4 nanocomposites (PANI@CFs) by in situ polyme... more In this study we have synthesized polyaniline/CoFe2O4 nanocomposites (PANI@CFs) by in situ polymerization method with different amounts of the CoFe2O4 nanoparticles NPs (CF-NPs) (0.5 g and 1.0 g). The structural optical, thermal and dielectric properties of the as synthesized PANI@CFs were studied. The XRD analysis ensures that CF-NPs have a single phase spinel structure. The XRD and EDAX results confirmed that the CF-NPs were successfully incorporated in the PANI matrix. The crystalline size analysis revealed that the size increased with increasing CF-NPs amount in the PANI@CFs, because of the aggregation effect. TGA exhibited an enhanced thermal stability of the PANI@CFs as compare with PANI owing to the strong interaction between the CF-NPs and polymer matrix. The energy band gaps as calculated through the Tauc relation were found to be gradually higher with the increasing the amount of CF-NPs in PANI@CFs. The dielectric constants (ε', ε″), dielectric loss (tanδ) and AC conductivity (σac) were studied as the function of frequency and composition, which have been explained by 'Maxwell Wagner Model'. The high dielectric constant and ac conductivity were observed of PANI@CFs than PANI. Moreover, PANI@CF 1:2 exhibited the promising photocatalytic activity for the photo-decoloration of the methyl orange (MO) dye under UV light irradiation. Results also showed protection of photo-decoloration of the MO dye by the disodium ethylenediaminetetraacetate dehydrate (EDTA-Na2; C10H14N2Na2O8·2H2O) (hole scavenger) and tert-butyl alcohol (C4H10O) (radical scavenger) clearly suggested the implication of reactive oxygen species (ROS) in the photocatalytic activity of PANI@CF 1:2. It is encouraging to conclude that PANI@CF bears the potential of its applications in photocatalysis.
The effect of Ba-substitution at Sr site on the structure, magnetoresistance and magnetic propert... more The effect of Ba-substitution at Sr site on the structure, magnetoresistance and magnetic properties of La0.67(Sr1−xBax)0.33MnO3 samples with x = 0.00, 0.25, 0.50, 0.75 and 1.00 has been investigated. Single phase samples were obtained by a conventional solid state reaction method with rhombohedral (x = 0.00) and orthorombic (x = 1.00) structure. The grain size increases with Ba content. Low field magnetoresistance phenomenon at low temperature can be observed for all samples. However it vanishes at 300 K for x = 0.75 and 1.00. The variation of MR% value is small ranging between 16 to 18% at 100 K in an applied field of 1 T. All samples show a single magnetic transition from the ferromagnetic (FM) state to the paramagnetic (PM) state as the temperature increases. Curie temperature, Tc decrease with increasing Ba concentration.
... Microstructure of Pr0.67Ba0.33MnO3 Ceramic WONG JEN KUEN 1, a , LIM KEAN PAH 1, b , ABDUL HAL... more ... Microstructure of Pr0.67Ba0.33MnO3 Ceramic WONG JEN KUEN 1, a , LIM KEAN PAH 1, b , ABDUL HALIM SHAARI 1, c , CHEN SOO KIEN 1, d and NG SIAU WEI 1, e ... 122 (2002), p. 266-271. [11] HY Hwang, SW. Cheong, NP Ong and B. Batlogg: Phys. Rev. Lett. Vol. ...
Photopyroelectric spectroscopy is used to study the band-gap energy of the ceramic (ZnO + xSb{2}O... more Photopyroelectric spectroscopy is used to study the band-gap energy of the ceramic (ZnO + xSb{2}O{3}), x = 0.1 - 1.5 mol% and the ceramic (ZnO + 0.4 mol% Bi{2}O{3} + xSb{2}O{3}), x = 0 - 1.5 mol% sintered at isothermal temperature, 1280 °C, for 1 and 2 hours. The wavelength of incident light, modulated at 9 Hz, is kept in the visible range and the photopyroelectric spectrum with reference to doping level is discussed. The band-gap energy is reduced from 3.2 eV, for pure ZnO, to 2.86, 2.83 eV for the samples without Bi{2}O{3}at 0.1 mol% of Sb{2}O{3} for 1 and 2 hours of sintering time, respectively. It is reduced to 2.83, 2.80 eV for the samples with Bi{2}O{3} at 0 mol% of Sb{2}O{3} for 1 and 2 hours of sintering time, respectively. The steepness factor σ A which characterizes the slop of exponential optical absorption is discussed with reference to the doping level. The phase constitution is determined by XRD analysis; microstructure and compositional analysis of the selected areas are analyzed using SEM and EDX.
Thermal diffusivity measurement of the Bi-Pb-Sr-Ca-CII-O superconducting ceramic sample is report... more Thermal diffusivity measurement of the Bi-Pb-Sr-Ca-CII-O superconducting ceramic sample is reported. In this work camera flash and polyvinylidene difluoride (PVDF) film were respectively used as heating source and pyroelectric detector. The theoretical signal calculation based on Dirac-function approximation for camera flash temporal profile was used to deduce the thermal diffusivity. The measurement was done from 85 K to room temperature. The thermal diffusivity curve shows a dip at the resistive transition onset ...
... Practical samples usually are of finite size, where the sample thickness, L is ≤ 5s. Hence, t... more ... Practical samples usually are of finite size, where the sample thickness, L is ≤ 5s. Hence, the correction factors derived by Valdes [14] as shown in equation (2) is consider. ∑ ∞ = ... The pressure in the chamber was reduced to ≈ 10-3 torr by using a rotary vane pump. ...
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