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.
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.
MeSH terms: Attention; Body Weights and Measures; Crystallization; Physics; Semiconductors; Temperature; Phase Transition; Biological Processes; Physiological Processes
An experimental study of the field emission from nitrogen doped Diamond-Like-Carbon (DLC) thin films prepared by plasma Chemical Vapor Deposition (CVD) was carried out for the purpose of investigating the characteristic of field electron emission from the surface of nitrogen doped DLC thin film. Thin DLC film was deposited on silicon using the plasma CVD method, from a mixture of Methane (CH4), Helium (He) and Nitrogen (N2) at room temperature. Emission current was measured while high volume of voltage was applied between the cathode-anode diode structures. Barrier height was obtained by current density-electric field (J-E) characteristic in the relation of Fowler-Nordheim equation. The value of barrier height in range of 0.03eV to 0.06eV was obtained and considered as low barrier.
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.
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%.
MeSH terms: Animals; Bone and Bones; Calcium Carbonate; Carbonates; Cattle; Female; Malaysia; Spectroscopy, Fourier Transform Infrared; Durapatite; Anthozoa
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
The amount of sugarcane bagasse and rice straw in the state of Perlis (Malaysia) is abundant while its utilization is still limited. One of the alternatives for the bagasse and straw utilization is as pulp raw material. This paper reviews on pulp from sugarcane bagasse and rice straw and its suitability for paper production. In this study, the pulp was extracted by the Soxhlet extraction method. The objective of this study was to investigate the cellulose, lignin and silica content of the pulp from sugarcane bagasse and rice straw. For rice straw, the presence of large amount of pentosanes in the pulp and black liquors, which also contain silica were decreased the using of straw in the paper industry. Therefore, formic acid pulping and NaOH treatment are studied to reduce or prevent silica. The isolated pulp samples were further characterized by Scanning Electron Microscope (SEM) to investigate their fiber dimensions.
Mechanical activation of quartz was carried out in jet mill at various specific kinetic energy level and classifier speed. The characterization of the particle size, crystallite size, amorphism rate and lattice strain was conducted on the feed and mechanically activated particles. The area under the prominent quartz peak was used to calculate the amorphism rate of the mechanically activated particles. Scherer equation was used to determine the crystallite size of the feed and mechanically activated particles. Mean particle size less than 5μm was obtained when the specific kinetic energy is ranging between 500 kWh/ton and 1000 kWh/ton. Amorphism of the mechanically activated particles up to 18% was observed at 500 kWh/ton. The crystallite size and lattice strain is influence by the intensity of the specific kinetic energy and classifier speed. The reduction in the crystallite size up to 39% was observed where the minimum crystallite is 23nm. The lattice strain is ranging from 0.024 to 0.038 respective to the specific kinetic energy and classifier speed.
Many attempts have been focused in the past on preparing of synthetic E-tricalcium (E-TCP), which being employed as bone substitute due to its biocompatibility and resorbability. Low temperature synthesize such as sol-gel method become popular due to the high product purity and homogenous composition. Sol-gel method is less economical towards commercialization because the cost of raw materials and the yield of the product that can be achieved. This paper describes the synthesis of ETCP via mixing of CaCO3 and H3PO4 followed by calcinations process at 750qC – 1050qC. X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimeter (DSC), fourier transformation infra-red (FTIR) were used for characterization and evaluation of the phase composition, morphology, particle size and thermal behavior of the product. E-TCP phase start to occur after calcinations at 750qC.
Fly ash (PFA) is a complex material produced after combustion in coal-fired power plants. About half of this fly ash is disposed as solid wastes. A possible alternative to disposal of the fly ash is the synthesis of zeolite. Zeolite Boggsite (Na37Ca74Al185Si775O192 7H2O) was synthesized from fly ash by hydrothermal treatment with NaOH solutions as identified by x-ray diffraction. The zeolite type and degree of crystallization were found to be dependent on the reaction conditions and mineralogy of the raw material, particularly in terms of the relative concentrations of SiO2 and Al2O3.
Ni–SiC composite coatings were electrodeposited from a Watts-type bath containing 5 g/l SiC particles in suspension. The particles were dispersed with the aid of mechanical agitation at 75 rpm and 150 rpm. EDX analysis confirmed the existence of Ni and SiC in the coatings. The effects of agitation speed on hardness properties of the coatings were investigated. SEM results showed that lower agitation speed could improve the amount of co-deposited SiC particles and increase the hardness of the composite coatings. The bonding between the Ni metal matrix and the SiC ceramic particles was compact.