[en] For the on-line estimation of uranium in uranium-HN0₃ binary solutions an empirical relationship between density of solution, uranium concentration and HN0₃ molarity has been developed. This is being used successfully for the on-line estimation of uranium in process control. It requires very little experimentation work and save lot of time and chemicals, needed in other chemical methods. (Author)

[en] The purpose of this study was to determine the adsorption coefficient (KOC) of chlorpyrifos in clay soil by measuring the Freundlich adsorption coefficient (Kads(f)) and desorption coefficient (1/n value) of chlorpyrifos. It was found that the Freundlich adsorption coefficient (Kads(f)) and the linear regression (r2) of the Freundlich adsorption isotherm for chlorpyrifos in the clay soil were 52.6 L/kg and 0.5244, respectively. Adsorption equilibrium time was achieved within 24 hours for clay soil. This adsorption equilibrium time was used to determine the effect of concentration on adsorption. The adsorption coefficient (KOC) of clay soil was found to be 2783 L/kg with an initial concentration solution of 1 μg/g, soil-solution ratio (1:5) at 300 C when the equilibrium between the soil matrix and solution was 24 hours. The Kdes decreased over four repetitions of the desorption process. The chlorpyrifos residues may be strongly adsorbed onto the surface of clay. (Author)

[en] The paper relates a study on the development of an analysis procedure for measuring the gold coating thickness using EDXRF technique. Gold coating thickness was measured by relating the counts under the Au L? peak its thickness value. In order to get a reasonably accurate result, a calibration graph was plotted using five gold-coated reference standards of different thickness. The calibration graph shows a straight line for thin coating measurement until 0.9 μm. Beyond this the relationship was not linear and this may be resulted from the self-absorption effect. Quantitative analysis was also performed on two different samples of gold coated jewelry and a phone connector. Result from the phone connector analysis seems to agree with the manufacturer gold coating value. From the analysis of gold-coated jewelry it had been able to differentiate the two articles as gold wash and gold electroplated. (Author)

[en] The land of Tanah Putih, Gua Musang, Kelantan (Malaysia) is well-known for its wealth in industrial mineral resources, especially aluminosilicate of feldspar and mica. Natural feldspar and mica were physicochemically characterized with regard to X-ray diffraction (XRD), nitrogen sorption analysis and transmission electron microscopy (TEM) techniques for qualitative and quantitative identification of feldspar and mica. They show a good crystallinity, high surface area and uniformity of meso porous structures. For the purpose of this experiment, the aluminosilicate of feldspar was modified either by acid treatment, or grafting the silanol groups present with various functional groups including aminopropyl-, octyl-, vinyl-, mercapto- and glycidoxy-triethoxy silanes, or activation of pre-treated support with glutaraldehyde. These support derivatives were used for further utilization in the immobilization of lipase from Candida rugosa and resulted in various interaction mechanisms between enzyme and introduced supports. It seemed that the features of the functionalized feldspar surfaces provide a preferable environmental host to enable the adsorption of lipase via interfacial adsorption method. Lipase immobilization onto feldspar support were further confirmed by scanning electron microscopy (SEM) coupled with energy dispersive X-ray microanalysis (EDX), transmission electron microscopy (TEM) and infra-red spectroscopy (FTIR) techniques. Enhancement of protein loading (up to 8.22 mg protein/ g support) and immobilization yield (up to 78 %) were shown by modified feldspar-lipase derivatives compared to unmodified feldspar support.(author)

[en] Thin film of cerium oxide (CeO₂) were prepared on silicon (Si) substrate by metal organic decomposition route. 0.25 M of cerium (III) acetylacetonate (acac) was used as starting materials with the addition of methanol and acetic acid as solvents. Oxide conversion of the film by thermal treatment was conducted at temperature ranging from 400 degree Celsius to 1000 degree Celsius for 15 min in argon ambient. X-ray diffraction (XRD) analysis utilizing Cu_kα radiation (Model Brukker Diffrac^Plus), Filmetrics system measurement, field emission scanning electron microscope (FESEM) (Model Zeiss Supra 35 VP FESEM) and atomic force microscopy (AFM) (Model SII Nanonavi) were employed to characterize the phase formed and morphologies of the film produced. (author)

[en] The hard coat anodising process was done by using different concentration of H₂SO₄ from 0 % to 20 %. The 90 volt of anodising process was applied by using Al foil as cathode materials. The surface changes on PM Al-Mg resulted by hard coat anodising was characterised by XRD measured. Surface hardness was measured by Micro-Vickers hardness machine. The experiment found different XRD pattern between anodised PM Al-Mg samples. The study was found by that the optimum value for H₂SO₄ concentration was 15 % H₂SO₄ and result 26 μm thickness, 5.07 % of mass changes and HVN 105.4 hardness. The hard coat anodising was affected to the XRD pattern for PM Al-Mg. (author)

[en] In these studies, cordierite was mechanically synthesized after a sol-gel process. The effect of milling time of cordierite was investigated. Aluminium nitrate nonahydrate, magnesium nitrate hexahydrate and tetraethyl orthosilicate (TEOS) were used as starting materials. Gels obtained were mechanically activated in planetary ball mill by at 300 rpm grinding speed and grinding time (15 min, 30 min, 45 min and 60 min). Powders produced were characterized by X-ray Diffraction (XRD) and Field Emission Scanning Microscope (FESEM) and Energy Dispersive X-ray (EDX). EDX analysis proved that α-cordierite was formed at lower temperature (1200 degree Celsius) as compliment to without grinding, whereby it is formed at 1300 degree Celsius. FESEM analysis shows the size of the cordierite were in submicron scale. EDX analysis proved that magnesium, aluminium, silicon and oxygen are elements existed in cordierite. (author)

[en] New solid acid catalyst consisting of zirconium sulfate (ZS) supported on a pure-HMS hexagonal meso porous material (HMS) have been prepared and characterized. This heterogenous catalyst is able to make a contribution to the field of acid catalyst involving bulky organic molecules. XRD analysis shows that ZS is intact after impregnated on HMS surface and formed finely dispersed species. No ZS crystal phase was developed even at ZS loadings as high as 40 wt %. The occurrence of chemical interaction between ZS and HMS was observed by XPS analysis. Further, XRF results demonstrated that there is no leaching of ZS elements after impregnation. This study shows that ZS can be impregnated on HMS and would be a promising solid acid catalyst for acid-type reactions especially involving bulky organic molecules. (author)

[en] Cement and concrete has been widely used as shielding material in reactor nuclear in order to minimize exposure to individuals. In this paper we present boron based concrete as neutron shielding for nuclear reactor applications. Concrete specimens with dimension of 10 x 10 x 10 cm were used and irradiated with neutron radiation of 252-californium. Characterization of physical, mechanical and radiation attenuation properties of concrete were carried out. The results show that the shielding performance is better than ordinary concrete. From the result, we confirmed that the performance of the concrete/ boron carbide is suitable for practical use. (Author)

[en] ²¹⁰Pb dating, Mn and total organic carbon have been used in this study to determine the sedimentation rate and the productivity in coastal of Kelantan. Four sediment cores which are SF1, SF3, SF5 and SF7 were taken using the gravity corer on June 2008. The 125 μm dry sediment with particle mesh was used to determine the concentration of ²¹⁰Pb, Mn and total organic carbon. Activity level of ²¹⁰Pb was determined using the Tennelec XLB-5 Gross Alpha-Beta Counter, Canberra, after the ingrowth of ²¹⁰Pb by the outgrowth of ²¹⁰Bi. While the content of Mn was measured using the Perkin Elmer SCIEX Inductively Coupled Plasma Mass Spectrometry ELAN 9000 technique and the organic carbon content was estimated using combustion method. The analysed result showed the ²¹⁰Pb activity for all samples were decreasing from top to the bottom sediment. While the vertical profile of Mn concentration had scattered distribution throughout the core sediments. However, Mn concentrations in the samples were lower than the Mn concentration in the earth crust that is 770.00 mg/kg. Values of the total organic carbon (TOC) content are higher in sites that are closer with land and lower in offshore sites. The value of sedimentation rate was 0.59 cm yr^-1, 0.47 cm yr^-1, 0.36 cm yr^-1 and 0.46 cm yr^-1 for SF1, SF3, SF5 and SF7, respectively. This indicates various sediment age ranges and year of accumulation of sediments. It shows that the organic carbon contents produced Mn²⁺ during anaerobic decomposition process in the sediment. (Author)