Displaying publications 61 - 80 of 209 in total

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  1. Zaini Hamzah, Nurul Latiffah Abd Rani, Ahmad Saat
    MyJurnal
    Measurement of major cation such as Na+, K+, and Ca2+ in water are normally carried out using
    AAS, ICP-OES or flame photometry. In this study, an attempt was made to measure these cations
    using Energy Dispersive X-ray Fluorescent Spectrometry (EDXRF). Hot spring s water was taken from varies hot spring in Selangor and divided into two portions that is filtered and unfiltered. 5 mL of water samples were pipette into a special liquid cups (sample holders) which has a thin mylar film underneath. The MiniPal4 XRF instrument was used in this study. The resolution for the instrument use is 145 keV with energy resolution at 5.9 keV. The spectrum of cations were analysed by using MiniPal/MiniMate software to determine the cations concentration. For K+ and Ca2+, Al-thin filter was used and default filter was used for Na+. The concentration of Na+ obtained for filtered and unfiltered samples were ranged from 38.00 to 66.05 and 43.26 to 76.95 ppm. Meanwhile, concentrations of K+ for filtered and unfiltered samples were ranged from 2.42 to 8.07 and 6.18 to 29.28 ppm. Concentrations of Ca2+ for filtered and unfiltered samples were ranged from 2.59 to 10.94 and 3.18 to 12.99 ppm.
  2. Hishamuddin Husain, Abdul Razak Daud, Muhamad Daud, Nadira Kamarudin
    MyJurnal
    Heat treatment was introduced onto the aluminum coated low carbon steel to promote the formation of thin layer of oxide for enhancement of oxidation protection of steel. This process has transformed the existing intermetallic layer formed during hot dip aluminizing process. Experiment was conducted on the low carbon steel substrates with 10mm x 10mm x 2mm dimension. Hot dip aluminizing of low carbon steel was carried out at 750 ºC dipping temperature in a molten pure aluminum for 5 minutes. Aluminized samples were heat treated at 600 ºC, 700 ºC, 800 ºC, and 900 ºC for 1 hour. X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and EDAX were used in investigation. From the observation, it showed the intermetallic thickness increased with the increase in temperature. The result of EDAX analysis revealed the existence of oxide phase and the intermetallics. The XRD identified the intermetallics as Fe2Al5 and FeAl3.
  3. Sreekantan, Srimala, Ahmad Fauzi Mohd Noor, Zainal Arifin Ahmad, Radzali Othman, West, Anthony, Sinclair, Derek
    MyJurnal
    Barium strontium titanate (Ba0.7Sr0.3TiO3) powder was processed at temperature 80 o C by reacting titania sol in aqueous solutions that contained BaCl2, SrCl2 and NaOH at atmospheric pressure.
    The structural characteristic of the powder and sintered pellet were studied using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) whereas the electrical characteristic was determined via Impedance Spectroscopy (IS) and LCR meter. The synthesized powder was found to have a tetragonal phase after heating at 1300 o C. XRD pattern also showed the presence of secondary phase BaTi2O5 (BT2). The SEM results shows the fine grain size was in the range of 0.2 Pm to 0.4 Pm whereas the large ones are approximately 0.8 Pm to 1.2 Pm The ac response of sample sintered at 1300 o C indicated that three electrically different regions. Element 1 can be assigned as a ferroelectric grain boundary region and it is actually BT2, element 2 as a ferroelectric bulk region and the third element is a conductive core which has a low resistance (200 :) and capacitance value.
  4. Ng, Boon Lim, Lockman, Zainovia
    MyJurnal
    Texture evolution of NiO formed during oxidation of polycrystalline single oriented (100) Ni-Cr was investigated. This foil was also termed rolling assisted biaxially textured substrate (RABiTS). X-ray diffractograms of oxidized Ni-Cr RABiTS foil showed the existence of mostly (200) NiO indicating (100)-type NiO formed exclusively on (100) singly oriented Ni-Cr grains. Epitaxial relationship between the two layers is observed. However the dual-in-plane texture was recorded.
    The in-plane texture was assessed by conducting phi scan and plotting series of pole figures measured at (111) NiO peak. The mechanism of the oxides formation was proposed to take into account the formation of (100)-type NiO. Cross section morphology of the oxidised foils reveals two oxidation layers; fast growing external layer consisting of the (100)-type NiO and an internal layer consisted of mostly Cr2O3 and maybe NiCr2O4. The thickness of NiO was ~ 10Pm. Cr2O3 formed as needle-like oxides embedded in a matrix of Ni foil. Inward diffusion of oxygen is believed to have caused this to happen. The external NiO layer was consisted of duplex microstructure characterised by columnar layer growing vertical on the surface of the metal and a few micron thick of equiaxed NiO. Delamination of the outer NiO layer often occurred at the columnarequiaxed interface which could be cured by CeO2 deposition on the foil prior to the oxidation process. CeO2 was deposited by conversion immersion using Ce(NO3)3.6H2O solution. (200) NiO formed on this coated sample as well.
  5. Hariyanti, Purwadaria, S., Zainal Arifin Ahmad
    MyJurnal
    Electrodeposition of white copper-tin alloys (including white miralloys) has been done onto planar mild steel substrates from alkaline cyanide solutions at 65 0 C. The chemical composition of the coating is influenced by plating bath composition and current density. White miralloy can be produced from the test solution containing 10 g/l CuCN2 - , 45 g/l Na2SnO3, 25 g/l NaCN, and 12 g/l NaOH at current density about 5 mA/cm 2 . The local compositions of the coating cross section were analyzed using EDX installed in a FESEM operated at an accelerating voltage of 20 kV. The phases formed during co-deposition process were identified using XRD at 25 mA current and 35 kV voltage.
  6. Hutagalung, Sabar D., Woon, Wu S., Khatijah A. Yaacob, Lockman, Zainovia
    MyJurnal
    P-type transparent conductive oxide of copper aluminum oxide (CuAlO2) thin films were prepared by using sol-gel method with nitrate solutions as starting precursor. Copper nitrate and aluminum nitrate were selected as raw materials that provide the copper and aluminum source. The CuAlO2 thin films were deposited on pre-cleaned silicon substrate by spin-coating technique. To study of phase formation of CuAlO2, as prepared sample was dried and subjected to heat treatment at various temperatures. The heat-treated samples were characterized by x-ray diffraction (XRD) and energy dispersive x-ray (EDX). From XRD analysis result found that CuAlO2 phase was formed after annealing at 1100 o C for 4 hrs. EDX result of annealed sample at 1100 o C shows composition of Cu and Al that indicate the possibility of forming CuAlO2.
  7. Julie Juliewatty Mohamed, Mohd Riduan, Hutagalung, Sabar Derita, Zainal Arifin Ahmad
    MyJurnal
    Dielectric material CaCu3Ti4O12 (CCTO) prepared by solid state technique, was calcined at different temperatures (700 - 1000 o C) for 6 and 12 hours. The calcined powder were analysed by XRD to identify the CCTO formation. Then the microstructure was observed by SEM. The CCTO single phase formation was firstly detected on sample calcined at 700 o C for 12 hours. The microstructure obtained shows the particles were spherical in shape. The grain getting larger as calcination temperature was increased.
  8. Prastomo, Niki, Lockman, Zainovia, Ahmad Fauzi Mohd Noor, Ahmad Nuruddin, Matsuda, Atsunori
    MyJurnal
    Tetragonal Y2O3 stabilized Zirconia (t-Y-ZrO2) powders were doped with Nb2O5 to seek a possibility if electronics doping would enhance the electronics conductivity of the insulating oxide. In this work Y2O3 was added as a stabilizer to produce tetragonal ZrO2 whereas Nb2O5 was added for the electronic doping. Several compositions of powders were prepared by thermal decomposition method and were post annealed at different temperatures. Precursor solutions were prepared from the mixture of zirconyl nitrate, yttrium nitrate and niobium tartarate as well as TEA (triethanolamine). The mixed solution were evaporated, pyrolysed and calcined to produce nanosized powders. The phase formation of the as-made powders was investigated by x-ray diffractometer. The additions of 7% Y2O3 were found to stabilize the tetragonal phase of zirconia.
    The addition of Nb2O5 did not alter the stability of the tetragonal phase but it was found that the conductivity of the material has changed. The band gap as measured by the UV-Visible Spectrometer gave a value in the range of 2.97 to 5.01 eV. XRD was also used to deduce the crystallite size (by using Scherer’s equation) and transmission electron microcopy was used to view the particle sizes and shapes. The Nb doped t-Y-ZrO2 prepared in this work was to be nanosized crystal with size ranges from 7 nm to 15 nm.
  9. Mohd Nazree Derman, Zainal Arifin Ahmad, Hussain, Luay Bakir, Nurulakmal Mohd Sharif
    MyJurnal
    A study of wear behaviour on anodised PM aluminium matrix composites (AMC) reinforced with Saffil™ alumina short fibres was done. AMC was fabricated by powder metallurgy methods (PM) with using Al flake powders and Saffil™ alumina short fibres. AMC reinforced with 15 wt % Saffil¥ alumina short fibre was selected because it showed optimum mechanical and physical properties. Sulphuric acid anodising process was performed and the objective is to obtain suitable parameters of sulphuric acid concentration, anodising voltage and anodising time on MMC. The study of anodising process was carried out with various sulphuric acid concentrations (from 0 to 20 % volume), anodising voltage (10 V to 20 V) and anodising time (from 0 to 60 minutes) at room temperature. Scanning electron microscope (SEM) was used to investigate coating morphology and thickness. From the research, anodising voltage of 18 V and 15 % vol H2SO4 in anodising time of 60 minutes were suitable parameters for sulphuric acid anodising of this AMC. SEM showed the coating thickness around 20 Pm. From the reserch, it was found that H2SO4 anodising was able to give good coating to MMC.
  10. Tabet, Tamer A., Fauziah Abdul Aziz, Shahidan Radiman
    MyJurnal
    Small-angle X-ray scattering (SAXS) was used to investigate the nanostructure of the microfibrils of cell wall in Acacia Mangium wood. Parameters, such as the fibre length (L), surface area of the single fibre (S), the correspondence distance from the center of the fibre to the center of its neighbor and the shape of the fibre were determined as a function to the distance from pith towards the bark. The results indicate that the fibre length ranged from 53.44 nm to 13.72 nm from pith to bark. Surface area of the single fibre varied from 0.65 nm 2 to 4.36 nm 2 , the highest being found at the end of bark region. The mean value of the correspondence distance is 13.95 nm. Surface structure analysis from scattering graph showed a rod shape of fibre in the pith region of Acacia Mangium wood. The use of SAXS technique and scanning electron microscope (SEM) micrographs gives the most reliable dimensions values.
  11. Masitah Alias, Zaini Hamzah
    MyJurnal
    The growing concern over the workers safety and health has lead many factories and organizations do the air monitoring to ensure the airborne at their workplace is safe for the worker’s health and complying the Occupational Safety and Health Act 1994 (Act 514). In this study, the monitoring covers an indoor air quality and chemical exposure to the workers in one of the power plant repair shop. A few workers from different sections namely blasting, welding, grinding, fitting and maintenance area were chosen to assist in the personal monitoring for 8 hours measurement. PM10 were measured at a few sampling points to collect dusts for 24 hours duration. The samples were brought back to the laboratory for gravimetric and SEM-EDAX analysis. The results were certainly exceed the limit for air quality, and many elements were detected such as Fe, Ni, Al, Si, Ca, K, Ba, S, Cr, Zn and Cl. The present of these elements shows that exposure to these particulate matters is quite risky and some measure needs to be taken for remedial action.
  12. Meor Yusoff, M.S., Masliana Muslimin
    MyJurnal
    The paper looks into the possibility of using standard addition method to analyse uranium and thorium in tin slag. Tin slag samples obtained from Butterworth was grind to 180 ȝm and injected with different concentrations of uranium and thorium. Linear calibration graphs were obtained for both these samples with R 2 values for uranium and thorium as 0.9989 and 0.9915 respectively. Based on this graphs, the initial uranium and thorium in the tin slag sample was established as 60 ppm for uranium and 160 ppm for thorium.
  13. Fadhlia Zafarina Zakaria, Fauziah Abdul Aziz, Thevarajah, Nahulan
    MyJurnal
    Some cortical bone specimens from the femurs of adult cows and sea coral of Porites species were studied by using Fourier Transform Infrared Spectroscopy, FTIR. Carbonate were shown to be present by indication of C-O stretch found between 1510-1410 cm -1 in both cortical bone and Porites. Based on the comparison of the relative intensity of CO3 2- bands with respect to the PO4 3- bands, peak intensity of Porites was found to be higher than peak intensity of cortical bone at carbonate band. This explains that Porites skeleton is made up of CaCO3 while bone consists of a mineral, hydroxyapatite Ca5(PO4)3OH with the present of carbonate ions, typically from 3 to 7 wt%.
  14. Meor Yusoff, M.S., Masliana Muslimin, Latifah Amin
    MyJurnal
    Tin slag was collected from a slag dump in the Penang Island and was analysed for its elemental composition using microfocus XRF with a 300ȝm x-ray spot diameter. The tin slag sample was analysed direct without any sample treatment and analysis was conduct on four different spots. The result gives different elemental composition on these different spots. Among the elements analysed are Al2O3, SiO2, SnO2, CaO, TiO2, Nd2O3, MnO, Fe2O3, TaO, W2O3, As2O3, ThO2, U3O8, ZrO2 and Nb2O5. Elemental mapping was also done to show the distribution of these elements in the sample.
  15. Rahbari, R., Hamdi, M., Farhudi, O., Yahya, R., Asmalina, M., Marzuki, Z.
    MyJurnal
    Self-propagating high-temperature synthesis (SHS) of powder compacts is a novel processing technique being developed as a route for the production of engineering ceramics and other advanced materials. The process, which is also referred to as combustion synthesis, provides energy- and cost-saving advantages over the more conventional processing routes for these materials. In the case of titanium or titanium alloy materials, prior researches employed powder metallurgy technology for preparing metal matrix composites, MMCs and laminated structures through the use of fine powders of an inert phase or phases (TiC, TiN, TiB and TiB2B ) dispersed in Ti or Ti alloy powders. The present research relates to manufacture of titanium-ceramic composites that are synthesized by combustion synthesis (SHS) and retains a multilayered composite microstructure comprising one or more titanium-based layers and one ceramic titanium carbide layers.
  16. Razak Mohd Ali Lee, Khairul Anwar Mohamad, Katsuyoshi, Hamasaki
    MyJurnal
    We put attention on Intrinsic Josephson Junction (IJJ) to study the fundamental physic for device applications. Convenient self-flux method was used to grow BSCCO single crystals. We investigated the lid effect to examine the single crystal growth of high TC (Critical Temperature). We found that for the crystal growth with no lid, two stage transitions of TC ≅ 61 K and 77 K were observed. While for the crystal growth with lid, the BSCCO has TC ≅ 80K, ΔTC = 10K and approximately average size5x2mm 2 . When we increased weight of lid, the single crystal have increased to TC =80K, ΔTC = 4K and the typical size was ≅7x3mm 2 . TC and the crystal growth show a tendency to increase by the effect of the lid. From observed quasi-particle characteristics, c-axis direction changed from semiconductor to intrinsic Josephson characteristic with decreasing temperature.
  17. Mohammad Syahmi Nordin, Fauziah Abdul Aziz
    MyJurnal
    The low resolution Automatic Picture Transmission (APT) data from the National Oceanic and Atmospheric Administration (NOAA) polar-orbiting satellites Advanced Very High Resolution Radiometer (AVHRR) is being received and recorded in real-time mode at ground receiving station in School of Science and Technology, Universiti Malaysia Sabah. The system is suitable for the developing and undeveloped countries in south and Southeast Asia and is said to be acceptable for engineering, agricultural, climatological and environmental applications. The system comprises a personal computer attached with a small APT receiver. The data transmission between the ground receiving station and NOAA satellites is using the electromagnetic wave. The relation for receiving and processing the electromagnetic wave in the transmission will be discussed.
  18. Jamal, Z., Idris, M.S., Irzaman, Barmawi, M.
    MyJurnal
    Ceramic of BaxSr1-xTiO3 (BST) for x =0.3; 0.5 and 0.7 were successfully deposited by solid solution method. The BST ceramic were analyzed by x-ray diffraction (XRD). The XRD spectra was recorded on a Philips type PW 3701 diffractometer using CuKD (Oco = 1.54056 Å) radiation at 30 KV and 30 mA (900 watt). The spectra shows that BST ceramic are polycrystalline with tetragonal structure. The lattice constants analysis of the grown ceramics was analyzed by visual basic program. Using Cohen’s and Cramer’s algorithms in visual basic program, , the lattice constants are a = b = 3.877 Å; c = 3.970 Å for Ba0.3Sr0.7TiO3 ceramic, a = b = 3.979 Å; c = 3.981 Å. for Ba0.5Sr0.5TiO3 ceramic and a = b = 3.965 Å; c = 4.005 Å for Ba0.7Sr0.3TiO3 ceramic, respectively. The reform value of the lattice constant of BST ceramic is possibly associated with the anti site defects of Ba and Sr.
  19. Mayappan, Ramani, Ahmad Badri Ismail, Zainal Arifin Ahmad, Hussain, Luay Bakir, Ariga, Tadashi
    MyJurnal
    In this study the intermetallic (IMC) thickness of Sn-Pb, Sn-Zn and Sn-Zn-Bi solders on copper (Cu) substrate were measured at different temperatures using reflow methods. Cu6Sn5 intermetallic phase was detected between Sn-Pb solder and Cu substrate. The J-Cu5Zn8 phase was detected between Sn-Zn and Sn-Zn-Bi lead-free solders with Cu substrate. The thickness of the intermetallics increases with temperature. The IMC thickness for Sn-8Zn-3Bi solder is lower than Sn-9Zn solder for all the soldering temperatures, indicating that Bi has suppressed the initial IMC formation.
  20. Afishah Alias, Fauziah Abdul Aziz, Abd. Rashid Hassan
    MyJurnal
    In this study, the unaffected, affected and heavily affected teeth were studied by using X-Ray diffraction method. The D-values, which are related to the crystallite size of the apatite crystals, were calculated according to the Sherrer equation. The crystallite size of unaffected enamel was found to be 1530.95Å, while the affected enamel was 1490.22Å and the heavily affected enamel was 1484.16Å respectively. This study showed that the unaffected enamel has greater crystallite size as compared to the affected and heavily affected enamel.
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