Abdullah Chik

Treated Oil Palm Ash as Precursor in the Zeolite Synthesis

In this study, the ability of treated oil palm ash aided with kaolin powder to produce zeolites is studied. The palm ash has been treated with citric acid via a leaching process to get rid of the metallic impurities in it. The usage of treated oil palm ash in the zeolites conversion seems to be an option for waste materials management. Characterization of treated oil palm ash from Malaysia’s palm oil plantation has been cleared. The treated oil palm ash and kaolin powder are used as the starting material for the synthesis of zeolites materials. The method chose for the zeolites conversion is alkaline hydrothermal treatment. The chemical composition, crystalline phases and elemental composition of treated oil palm ash and as-synthesized samples were characterized and studied. From the analysis, the treated oil palm ash was a fertile source of silica and exists as quartz phase. The outcomes have significant motivation for the production of zeolites by using low cost material such as treated oil palm ash.

Effects of Acid on the Performance of Polishing Process

The serious quality problem in the magnetic substrate during polishing process by using conventional lapping machine had generate the idea to develop a doubled-sided lapping machine of polishing stone manufactured of an abrasive and resin. After certain parameter of polishing process, the polishing stone starts to clog because of debris agglomeration from the polishing substrate, thus lead to the scratches on the magnetic substrate which will affect its performance. Three difference type of acid were used as to dissolve the debris agglomeration in the polishing stone. The influence of oxalic, phosphoric and citric acid at three different times were examined. It was found that oxalic acid is the best chelating agent in dissolving the debris in the polishing stone.

Zeolite synthesis from oil palm ash using hydrothermal treatment

The treated oil palm ash and kaolin powder are used as the starting material for the synthesis of zeolites materials. The method chose for the zeolites conversion is alkaline hydrothermal treatment. The chemical composition and crystalline phases of treated oil palm ash and as-synthesized samples were characterized and studied. From the analysis, the treated palm ash was a fertile source of silica and exists as quartz phase. The zeolite synthesis was carried out under hydrothermal conditions by activation with sodium hydroxide (NaOH) solution. The results indicated that the synthesized zeolite products obtained from 2 M NaOH concentrations contain zeolite gismondine as major constituent phase, whereas quartz was found as minor phase. The outcomes have significant motivation for the production of zeolites by using low cost material such as treated palm ash.

Effect of Al Excess on the Band Structure of ZnO Using Density Functional Theory

The effect of Al doping to the band structure of ZnO was studied in this paper. The electronic band structure of Al doped ZnO was determined by using first-principles based on density functional theory. ABINIT was used to perform the band structure calculation. The calculated band structure of ZnO and Al doped ZnO shows that ZnO is a direct band gap semiconductor. The band structure become narrow with Al doping compared pure ZnO. With Al doping, the band gap of ZnO (0.749 eV) become smaller as the concentration Al doping increased to 4wt% (0.551 eV). The electrical conductivity of Al doped ZnO was studied as a references value for the band gap. The electrical conductivity of ZnO (8.21 S/cm) was enhanced with Al doping increased to 4wt% (71.87 S/cm).

Ab Initio Calculations of Electronic Properties of Al Doped LaMnO3 Perovskite Manganites

The electronic structure of the perovskite manganites LaMnO3 and La2/3 Al1/3 MnO3 was presented. The calculations were made within density functional theory (DFT) and PBE exchange correlations energy approximation. It was found that inclusion of Al dopants add additional states near the Fermi level and decreasing the resistivity values for all temperature range.

Ab Initio Calculations of Electronic and Magnetic Properties of AlMnO3 Perovskite Manganites

The electronic structure of the perovskite manganites AlMnO3 cubic crystal was presented. The calculations were made within density functional theory and PBE exchange correlations energy approximation. It was found that the crystal exhibit covalent bonding between Mn and O with superexchange mechanism. At groundstate, AlMnO3 stabilizes in antiferromagnetic structure with semi metallic like nature at the ground state.

Study the Properties of Abrasive Stone for Aluminum Grinding

A doubled-sided lapping machine of grinding stone manufactured of a SiC as an abrasive, specific resin and other thermosetting resin were developed for grinding process of the substrate of hard disk drive (HDD) made up of aluminum since the conventional lapping machine cause the serious quality problem of the magnetic substrate. However, at certain parameter during the grinding process, the abrasive stone was clogging due to the agglomeration of debris from the substrate which cause scratches on the magnetic substrates and affect its performance. The samples were classified into four parts (soft spot, border spot, hard spot, and unused spot). Characterizations of the samples were done using XRF, SEM and FTIR analysis. Based on all the above analysis, it can conclude that the porosity of the stone were not homogeneous and the percentage of Al was highest at the border spot which shows that, the area at the border spot cause the clogging to occur thus produces the hard spot that will damage the magnetic substrate during grinding process.

Physical Characteristic of Zn Doped Soft Ferrites MxZn1-x Fe2O4

The chemical composition and preparation methods for ferrite were studied in order to control the quality of ferrite such as higher initial permeability and low energy losses. Nine samples of soft ferrite MxZn1-xFe2O4 with M=Ni, Mg, Cu ; x=0.2, 0.3, and 0.4 was prepared using solid state ceramic method and characterized for initial permeability, coercivity and relative loss factor (RLF). Studies show that samples with low Zn concentration, x=0.4, exhibit higher initial permeability, μi, with magnitude highest in sample with Ni concentration, that also has the highest atomic susceptibility among Ni, Mg and Cu. Initial permeability, μi ,also influences the resistivity of the samples with increasing susceptibility of magnetic spins, so samples with higher μi, e.g. Ni0.4Zn0.6Fe2O4 exhibit increased resistivity with increased initial permeability while Cu0.4Zn0.6Fe2O4 exhibit decreasing resistivity with increasing Cu content and lower initial permeability.

Extraction of silica from palm ash using organic acid leaching treatment

Agricultural wastes such as palm ash and rice husk have a possibility to be used as a usefully renewable source for production of energy and silica (SiO2). Extensive researches have been carried out to extract silica from agricultural wastes such as rice husk, due to silica as a useful raw material for industrial application. In the previous studies, the strong acid leaching treatment was carried out to remove metallic impurities and organics contained in rice husk. A strong acid leaching treatment, however, is significantly hazardous to the environment and people [. In this study, the environmentally benign and economically effective process to produce SiO2 materials from palm ash has been established by using citric acid leaching, not the conventional strong acids. Results showed that silica can be extracted from palm ash using citric acid leaching treatment under the optimum extracting conditions with 70°C of solution temperature, 60 minutes of reaction time and concentration of citric acid of more than 2%. The purity of silica extracted is more than 90%.

Preparation of Colossal Magnetoresistance Ploycrystalline via Sol-Gel Technique: A Short Review

This paper presents a short review of research work on the development of synthesizing the colossal magnetoresistance materials through sol-gel method. Although there are a lot number of methods available, sol-gel method has been widely used and some excellent work has been reported. Two different manganite systems, which are LSMO and PSMO, that have been prepared through sol-gel method was choose for the discussion purpose. It was found that both systems were successfully prepared via the sol-gel method. Both systems showing better magnetoresistance properties compare to sample prepared through solid state reaction. X-ray diffraction technique was used to study the structural characteristic. Atomic force microscope and field emission scanning electron microscope were used in order to investigate surface morphology. Resistivity as a function of temperature was measured by a standard four-probe method.