Key Engineering Materials Vols. 594-595

Abstract: Copper oxide films were prepared via sol-gel like spin coating starting from methanolic solutions of cupric chloride onto the TiO₂ substrates. Films were obtained by spin coating under room conditions (temperature, 25-30 °C) and were subsequently annealed at different temperatures (200-400 °C) in oxidizing (air) and inert (N₂) atmospheres. X-ray diffraction (XRD) patterns showed crystalline phases, which were observed as a function of the annealing conditions. The film composition resulted single or multi-phasic depending on both temperature and atmosphere. The grain size of film was measured using scanning electron microscopy (SEM) and the surface roughness of thin films was characterized by atomic force microscopy (AFM). The grain size of which was annealed in air at 300 °C was 30.39 nm with the surface roughness of 96.16 nm. The effects of annealing atmosphere on the structure and morphology of copper oxide thin films are reported.

Abstract: In this project, iron mill scale has been used to produce iron powder that can be used within the Powder Metallurgy process. To achieve this objective, the iron mill scale needs to be refined. This involve the work of grinding the iron mill scale to an effective particle size, which is 300μm. Latter, the grounded iron mill scale will undergo the magnetic separation process. The purpose of this process is to remove any non-magnetic material. Than the following process is to fully oxidize and reduce the iron mill scale to form pure iron powder. From this step an optimum value for maximum heating temperature, heating rate and heating cycle was determined. Than in order to determine whether the oxidation and the reduction process have completely achieved their objective, the iron oxide and the iron powder that have been produced from both process, was characterized using X-Ray Diffraction Analysis (XRD) and X-Ray Florescent Analysis (XRF) technique. From the oxidation process, it is obvious that sample C gave higher oxidation percentage, which is 11.22%. While Reduction 2 shows the desirable result, which is 29.51% of reduction, involving a low cost compared to other reduction process.

Abstract: Since the metallic elements are covered with or encapsulated by various plastic or ceramic materials on printed circuit boards (PCBs), a pre-treatment process allowing their liberation and separation is first needed in order to facilitate proficient extraction. In this work, a fundamental study has been carried out to recover metallic concentrates from PCBs scraps. The most important step is to separate or release particles from the associated gangue minerals at the possible liberation particle size. The samples of printed circuit boards were separated into the magnetic and non-magnetic fractions by Rare-earth Roll Magnetic Separator. Then, the magnetic and non-magnetic fractions were separated to heavy fraction (metallic elements) and light fraction (plastic) by Mozley Laboratory Table Separator. Results show that the unliberated particles still remain in the comminution fines PCBs. The use of Rare-earth roll magnetic separation was clarified that the Fe, Ni and Zn element tend to be condensed in magnetic particles. Meanwhile Cu element tends to be release in non-magnetic particles. Mozley Laboratory Table Separation was capable to obtain fractions with relatively high concentrations of metallic elements. This study is expected to provide useful data for the efficient physical separation of metallic components from printed circuit boards scraps.

Abstract: Carbon fibers are produced from natural sources of water hyacinth plants that have been dried, ground and sieved to three different particle sizes of 600 μm, 300 μm and less than 300 μm. Through the analysis of data obtained from Differential Thermal Analysis (DTA) and Thermal Gravimetric Analysis (TGA), pyrolysis process was carried out at three different temperatures that is 320 ° C, 330 ° C and 350 ° C. Effect of different pyrolysis temperature on the properties of carbon fibers produced have been studied using Scanning Electron Microscope (SEM) analysis method. Results of SEM observed the carbon of the smallest particle size give the best structure and texture of surface morphology for optimum pyrolysis temperature of 330°C.

Abstract: When we use effectively shape memory alloys require knowledge of operational behavior at the thermal stresses and mechanical variables. Measurements performed on a CuZnAl alloy, revealed fatigue properties by considering the size of the maximum load deformation corresponding recovered memory. It requires knowledge in design fatigue behavior of shape memory alloy components after education, fatigue strength by performing partial memory loss or physical destruction. The properties of memory shape alloys recommend their use for complex mechanical applications in domains as follows medicine, robotics, aeronautics, electric contacts, actuators. Shape memory metal alloys in the construction of such installations are subject to mechanical stress, and the thermal stresses, so their inclusion in a computing system fatigue involves consideration of the function performed.

Abstract: The paper presents the obtaining of shape memory alloys, base copper and a diffractometer and microscopic study on some samples. The study was made on CuZnAl samples, obtained by classic casting and educated. The shape memory alloys properties recommend their use for applications in domains as follows electric contacts, robotics, and aeronautics. When choosing the type of alloy used for the manufacture of the component parts of different industrial applications, it must be taken into account fatigue resistance, resistance to shocks and resistance to corrosion. Shape memory alloys are a unique group of alloys with the ability to remember a form even after quite severe plastic deformations. At low temperatures, shape memory alloys can be deformed apparently like other metallic alloys, but this deformation can recover with a relatively modest increase in temperature.

Abstract: Fly ash geopolymer coating material potential used to protect surface used in exposure conditions. Ratio of fly ash/alkaline activator and Na₂SiO₃/NaOH play important parameter on determining the best flexural strength of geopolymer coating material. Fly ash and alkali activator (Al₂O₃/Na₂SiO₃) were mixed with the solids-to-liquid ratios in range of 1.0-3.0 and different ratios of Na₂SiO₃/NaOH (1.0-3.0) to prepare geopolymer coating material at constant NaOH concentration of 10 M. Effect of fly ash/alkaline activator ratio and Na₂SiO₃/NaOH on geopolymer coating was determined with respect to the highest flexural strength of the 1200oC sintering temperature of geopolymer coating substrates. The results concluded that the highest strength for fly ash geopolymer coating material is achieved 42 MPa when the solid/liquid ratio is 2.0 and the Na2SiO3/NaOH ratio is 2.5.

Abstract: This paper presented the compressive strength of geopolymer paste with different NaOH concentration and morphology analysis for sintered artificial aggregate. This artificial aggregate was produce based on mix design with highest compressive strength which is 12 M. The sample was cured at 70 °C for 24 hours and then it was exposed to different temperature at range 500 °C to 700 °C. Scanning Electron Microscopy (SEM) has been used to identify the formation of microstructure. The geopolymer artificial aggregate was an alternative ways to produce a greener environmental. In this study, the compressive strength for different Na₂SiO₃/NaOH ratio has been analyzed. The morphology for best mix design then were analyze for different curing temperature. The result shows fly ash based geopolymer paste with 12 M of NaOH concentration shows excellent result with 7.30 MPa at 2.5 ratio of Na₂SiO₃/NaOH and for geopolymer artificial aggregate, when temperature of heat treatment increased, the open porosity of porous geopolymer surface decreased.

Abstract: This paper describes the design and development of remote communication system for mines detector robot. This project uses a PIC18F4580 microcontroller to control the robot movements and functions. A metal detector will be attached to the robot. The robot will have two operating modes; automatic and manual mode. In automatic mode, the robot will move according to a predefined track. When the robot is moving, the system produces feedbacks given by the sensors on the robot to the remote computer about the surroundings and when potential land mines are detected. In manual mode, the robot will be fully controlled by the remote computer for decision making process. All the controls and monitoring of data are displayed in a graphical user interface (GUI). The wireless module proposed is the XBee RF modules. The XBee modules were found to perform with optimum data transfer reliability at the range equals to 25% of its maximum communication range.

Abstract: Carbon dioxide (CO₂) removal from natural gas attracts more attention than other impurities due to its corrosiveness property and it also possess no heating value in the sales natural gas. Amine based chemical absorption has been used commercially for CO₂ separation in gas processing plant. However, the liquid amine based processes pose operating difficulties due to high regeneration energy, large equipments size and solvent leakage. This research studies modification of porous materials, zeolite NaY by grafting amine functional group using monoethanolamine directly to the surface of the solid sorbents. The structures and physical properties of amine modified adsorbent were characterized using powder X-Ray Diffraction (XRD), nitrogen adsorption at 77K and thermogravimetric analysis. Since application of Pressure Swing Adsorption (PSA) has been widely used in various plants in the world, this research was extended to study carbon dioxide separation using amine modified adsorbents in PSA experimental system. Effects of adsorption and regeneration behaviour on CO₂ separation were investigated. Amine modified NaY showed better result compared to unmodified NaY in term of improvement in physical and chemical properties, high CO₂ adsorption capacity and modified adsorbents were ease of regeneration.