Solid State Phenomena Vol. 317

Abstract: The expansion of the oil palm industry has affected the environment and the poor handling of oil palm waste has greatly endangered the habitat surrounds it. The oil palm natural fibre waste can be put to good use and used as a sound absorber for its amazing acoustic properties. At the same time, the demand for natural fibre sound-absorbing panels is increasing due to its low-cost fabrication and its healthier than synthetic fibre. This research has studied the acoustic properties of mixing Empty Fruit Bunch (EFB) and Oil Palm Frond (OPF) in a thickness of 12 mm, 14 mm, 16 mm, and 18 mm. The fibreboard has been fabricated at a density of 120 kg/m³. The Sound Absorption Coefficient, SAC, and morphologies of all the samples were examined using the Impedance Tube Method (ITM) and Scanning Electron Microscope, (SEM). The sample’s SAC value increased with thickness. It is noteworthy that this combination percentage of natural fibres of EFB and OPF show good acoustic performance where the SAC values above 0.8 at wide frequency 3000 - 6400 Hz. Sample thickness 14 mm, 18 mm achieved unity (1.0) at frequency 4000 - 5500 Hz. In addition, all the samples were found to exceed 90 % of the absorption rate in the range of 4500 - 6400 Hz. The morphology content of EFB and OPF helps in enhancing the absorption rate.

Abstract: In this paper, trap levels around the glass transition temperature (T_g) of polymers have been characterized using Thermally Stimulated Current (TSC) technique. Deconvolution on α-peaks of the T_g for PE (-104 °C), plasticized PVC (-35 °C), PMMA (90 °C) and PET (96 °C) were carried out based on the first-order kinetic theory for non-Debye relaxation. Using temperature, T from TSC experimental data, we have successfully separated the α-peaks of the thermoplastic polymers. It is found that the complex curve of α-peaks can composed of four (4) to eight (8) sub peaks. Dominant sub peaks were identified at T_max = -105 °C, -34 °C, 89 °C and 92 °C for PE, pPVC, PMMA and PET, respectively. These peaks show activation energy, E_a of shallow and deep trap centers ranged from 0.3 eV to 4.6 Ev where they represent the depolarization of localized dipoles and space charges relaxations in the polymers.

Abstract: The dielectric strength of insulating liquids of transformer acts an important parameter in the operation of transformer. Thus, great interest and many studies have been extensively done to improve the dielectric strength. One of study is the introduction of nanoparticle in the transformer oils. Study of the nanoparticles for the last few years had been found that, it can be dispersed in the transformers oils to be nanofluids and directly enhance the transformer performance. In this study, an investigation has been carried out to focus on the effect of silicon carbide (SiC) nanoparticle to AC (alternating current) breakdown voltage of the Refined, Bleached, and Deodorized Palm Oil (RBDPO). AC breakdown test have been conduct according to the standard of the IEC 60156. Besides that, a number of parameters will be evaluated such as dielectric dissipation factor (tan δ), relative permittivity (ε), and resistivity (ρ). Based on the results of the experiment, the electrode gap at 2.5 mm having the highest AC breakdown voltage compared to the other electrode gap which are 1.0 mm, 1.5 mm and 2.0 mm. Furthermore, doping with different concentrations of the silicon carbide (SiC) in Refined, Bleached, and Deodorized Palm Oil (RBDPO) found decreasing of AC breakdown voltage from 52.09 kV (without SiC) to 45.3 kV for 0.001 g/L, 43.2 kV for 0.003 g/L and 40.1 kV for 0.005 g/L respectively.

Abstract: This study focuses on preparation and characterization of polymer gel electrolytes (PGEs) based on agarose–LiBOB–DMSO and poly(1-vinylpyrrolidone-co-vinyl acetate)–LiBOB–DMSO. Two systems of PGEs were prepared by dissolving a different amount (1-8 wt.%) of agarose and (1-8 wt.%) P(VP-co-VAc) as host polymer in 0.8 M of LiBOB–DMSO solution. The addition of host polymer into 0.8 M of LiBOB–DMSO solution will result an optimum conductivity which is 6.91 x 10^-3 S.cm^-1 for agarose–LiBOB–DMSO system and 7.83 x 10^-3 S.cm^-1 for P(VP-co-VAc)–LiBOB–DMSO system. In the temperature range of conductivity studies discovered that the agarose–LiBOB–DMSO and P(VP-co-VAc)–LiBOB–DMSO polymer gel electrolytes abide by Arrhenius rule indicating that this PGEs could run at elevated temperature conditions. Furthermore, lithium transference number confirms that both electrolyte systems have 0.03 and 0.12 respectively at room temperature (298 K). Linear sweep voltammetry (LSV) measurements demonstrate the agarose–LiBOB–DMSO system has a potential of 4.26 V and P(VP-co-VAc)–LiBOB–DMSO system has a potential of 4.50 V which is good in electrochemical stability.

Abstract: In this work, the film contained a mixture of PMMA, salt, and plasticizers are studied. PMMA as a host polymer, ammonium trifluoromethane sulphonate or ammonium triflate (NH₄CF₃SO₃) as a doping salt and ethylene carbonate (EC) as a plasticizer is used in this present study. PMMA salt complexes system and plasticized PMMA salt complexes system are prepared by solution cast technique at room temperature. FTIR is used to study the interaction between polymer and salt, and between polymer–salt and plasticizer. The carbonyl group C=O asymmetric stretching mode observed at 1721 cm^-1 is broadened and shifted to lower wavenumber when ammonium triflate was added into PMMA. The broadening, shifting and reduction in wavenumbers of FTIR spectra show that the complexation has occurred between the polymer and salt. EIS is performed to measure the electrical conductivity of the polymer–salt system prepared at ambient temperature. The electrical conductivity of film containing 1.0 g of PMMA–35 wt% NH₄CF₃SO₃–16 wt% EC exhibit the highest electrical conductivity with the value of 2.461 x 10^-4 S/cm². XRD is carried out to study the pattern of pure PMMA, PMMA–NH₄CF₃SO₃ and PMMA–NH₄CF₃SO₃–EC. The XRD analysis shows the addition of plasticizer to the polymer–salt system increase the amorphousness of the polymer electrolytes hence increases in conductivity.

Abstract: Layered lithium iron hydroxysulfate, LiFeSO₄OH was recently proposed as a cathode material for lithium ion batteries (LIBs) made up of low cost and sustainable components. Here, we report ab-initio investigation into the structural properties of its sodium analogue, NaFeSO₄OH obtained from in-situ substitution of lithium (Li) with sodium (Na). A robust host structure for NaFeSO₄OH was discovered owing to strong Fe-O and S-O bonds, a good indicator for thermal stability and long cycle life. The Na ions are strongly held by the oxygen atoms, but the charge density map proves that the bond between the two is still ionic.

Abstract: The main objective of this study is to perform a structural analysis of NiO-BCZY anode functional layer (AFL) with different weight ratio (NiO:BCZY = 20:80 and 40:60). NiO commercial powder and in-house developed BCZY synthesized by a sol-gel method are mixed and ground and then sintered at 1450° C for 5 hours to produce AFL powder. The single-cell (anode | CG-AFL| electrolyte | cathode) is fabricated with the anode substrates firstly die-pressed, then compositionally gradient anode functional layer (CG-AFL) and spin-coated with electrolyte thin film, accordingly. Structural characterization of AFL powder and conductivity of the single cell is performed using room temperature X-ray diffraction (XRD) and in-house developed electrochemical impedance spectroscopy (EIS) test station, respectively. Rietveld refinement analysis of the XRD data confirms the high purity single phase of NiO and BCZY. Both NiO and BCZY show a cubic crystal structure and each belongs to space group Fm-3m and Pm-3m, respectively. The lattice parameter (a = b = c) of NiO and BCZY are about 4.1818 ų and 4.3433 ų for 20NiO-80BCZY and 4.1825 ų and 4.3439 ų for 40NiO-60BCZY. EIS results show ohmic resistance (R_S) and polarization resistance (R_P) of the single cell are 14.8 and 16.23 Ωcm² at 800 °C, respectively.

Abstract: A modified sol-gel method using metal nitrate salts was adopted to synthesis proton conductor of Ba(Ce_1-xZr_x)_0.95Yb_0.05O_2.975 where x=0.2, 0.3, 0.4, 0.5 and 0.6 ceramic powders. The aim of this work is to study the crystal structure of Yb-doped barium cerate solid solution at different Zr concentrations. The powder was calcined at 1100°C for 12 hours and pressed at 5 tons to become a pellet by a dry pressing technique. The pellet was sintered at 1400°C in air for 6 hours and ground to powder form prior to the X-ray diffraction measurement. The raw diffraction data of the sample at room temperature was analyzed using Rietveld refinement method in X’pert Highscore software. Cubic crystal structure was observed by software with goodness of fit in average 2.82. Phase formation, structure analysis and the empirical rule which holds the linear relation between lattice parameters at different Zr concentrations using Vegard’s Law were also presented and discussed.

Abstract: A fuel cell is an electrochemical device that provides efficient power generation. Solid fuel oxide cell (SOFC) is an electrochemical device that generates electrical energy and heat from the gaseous state of fuel using an oxidant. SOFC is a highly efficient and environmentally friendly power generation technology that generates electrical energy from hydrogen gas, natural gas and other renewable fuel. The implementation of SOFCs is still facing challenges because their performance needs to be improved. Constructing cells with solid material alone is difficult because good electrical contacts between the components must be maintained. The concept of a dual composite cathode is important for the development of SOFC single cells. Introducing dual composite cathode can create an ideal cathode microstructure that can improve phase contiguity and interfacial coherence. This paper reviews the behaviour of a perovskite-type oxide-based dual composite cathode of SOFC for the selection of suitable materials and the preparation of a dual composite cathode.

Abstract: The development of biopolymer electrolytes based on methylcellulose (MC) has been accomplished by incorporating ammonium bromide (NB) to the polymer-salt system. The biopolymer electrolytes were prepared via solution-casting method. The conductivity and permittivity characteristics of the material were studied. The biopolymer-salt complex formation have been analysed through Fourier Transform Infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The conductivity of the sample was measured by EIS HIOKI. Upon addition of 20 wt.% of NB, highest conductivity of 3.25×10^-4 μScm^-1 was achieved at ambient temperature. The temperature dependence of the biopolymer electrolytes exhibit Arrhenius behaviour. This result had been further proven in FTIR study.