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Corrosion Behavior of Ni3(Si,Ti) + 2Mo in Hydrochloric Acid Solution

The corrosion behaviour of the intermetallic compounds Ni3(Si,Ti) (L12: single phase), has been investigated using an immersion test, electrochemical method, scanning electron microscope in 0.5 kmol/m3 HCl at 303 K. In addition, the corrosion behaviour of austenitic stainless steel type 304 and C276 was studied under the same experimental conditions as references. It was found that the intergranular attack was observed for Ni3(Si,Ti) in the immersion test. From the immersion test and polarization curves, Ni3(Si,Ti) had the moderate corrosion resistance, while the corrosion resistances of C 276 and type 304 were the highest and the lowest. Ni3(Si,Ti) and type 304 were difficult to form a stable passive film, but not for C276. A further experiment must be conducted to clarify the stability of film for Ni3(Si,Ti) in detail.

Properties of carbon nanotubes-doped Fe-sheath MgB2 for superconducting wires

Magnesium diboride (MgB2) is a potential superconductor materials that could be applied as superconducting wires due to its relatively high critical temperature. To study the influence of carbon nanotubes (CNT) on MgB2 wire manufacture, CNT-doped MgB2 superconducting wires have been fabricated from MgB2 and CNT powders sheathed in a SS304 stainless steel tube. In the process, the mixtures of MgB2 and CNT powders were inserted into the SS304 tubes and then were rolled and drawn. The properties of the fabricated superconducting wires were then analyzed through the crystal structure, surface morphology and temperature dependence of resistivity. The addition of CNT did not seem to have a significant influence on the crystal structure of Magnesium diboride. However, the addition of CNT caused the particle size of MgB2 became smaller. The temperature dependence of resistivity results showed that the critical temperatures were shifting linearly toward low temperatures due to the addition of CNT.

Removing ocular artifact of EEG signal using SOBI-RO on motor imagery experiment

Eye blinking known as ocular artifact cause changes to the electric fields over the scalp and as a result, EEG recordings are often significantly distorted and their interpretation problematic. In this paper, an algorithm using second order blind identification with robust orthogonalization (SOBI-RO) is used to remove the ocular artifact in a motor imagery experiment. Simulation results shows that the ocular artifacts are significantly removed and the sources of the brain activity are clearly identified. The identification performance using signal to distortion ratio value about 68.88% is achieved.

Study on Cold-Drawing in Powder-in-Tube Process in Fabricating Silver-Sheathed (Bi,Pb)-Sr-Ca-Cu-O Tapes

Since Cu oxide superconductors have been discovered, the application for this type of superconductor especially in the form of superconducting tape to be used as electric cable to transport the electricity. The aim to this study is to analyse the manufacture of superconducting wire with superconducting pellets as its precursor. A pellet disc of High Temperature Superconducting (HTS) Bi,Pb-Sr-Ca-Cu-O has been made by using solid state method. This pellet has been prepared by mixing each of oxide powders together, and then sintered at 865°C for 90 hours. We have analysed the samples using X-Ray Diffractometer (XRD), Energy Dispersive x-ray Spectroscopy (EDS), Scanning Electron Microscopy (SEM) and also resistivity measurement to confirm its superconductivity. After confirmed the superconducting properties of the pellet, it was grinded into powder and inserted into silver tube with outer diameter of 10 mm and thickness of 1 mm. And then, drawn to make monofilament wire. It were then cut and inserted into another silver tube, and then re-drawing and rolled into multifilament tapes using Powder-in-Tube (PIT) method. The multifilament tapes was heated at 850°C for 12 hours. We confirmed its phase crystalline and superconductivity at pellet disc. However, when the pellet disc was made into wire and sintered at 850°C, it became amorphous and conductivity behaviour was decline. According to SEM analysis and resistivity measurement result, silver also penetrated inside the sample region of multifilament wire.

Manufacture of Bi, Pb-Sr-Ca-Cu-O pellet disc using wet method

A confirmation of favorable properties of pellet disc of HTSBPSCCO is required in order to optimally do subsequent process of powder-in-tube (PIT) fabricated intosuperconductor wires. Wet method is a simple method in fabricating superconductor wire when it comes to mass production. In order to optimize this method, temperature parameter holds a decisive role in the formation of the 2223 phase of BPSCCO. We have synthesized two samples using wet method with the sintering temperature of 855°C and 865°C for 90 hours in air atmosphere.XRD analysis points out the formation of Bi-2223 phase of the sample with the sintering temperature of 855°C, whereas Bi-2212 phase is detected in the one with the sintering temperature of 865°C. The surface morphology of both samples are layers-like. According to temperature dependence of resistivity measurement results, both samples have superconductivity behavior below critical temperature (Tc). The former one (Tsintering = 855°C) has conductive-like behavior above Tcof which...

Effect of humid atmosphere on resistivity and crystallinity behavior of BPSCCO superconductor made by solid state method

High Tc superconductors (HTS) with the CuO2-based formula (Bi2-Sr2-Cam−1-Cum-Oy) are strongly hygroscopic material because their various phases in the CuO2-based material (Bi2-Sr2-Cam-1-Cum-Oy) are highly susceptible to attact moisture or water. In order to protect the HTS Bi,Pb-Sr-Ca-Cu-O (BPSCCO) from deterioration during fabrication process, controlled humid environment is prerequisite in formation of a stable and homogenous of 2223 phase of HTS BPSCCO. Samples have been synthesized using the solid state method with the sintering temperature of 865°C for 90 hours in air. The formation of Bi-2223 phase has been detected by XRD analysis on the samples before and after been exposed to water vapour at 40°C for 3 days. However, excessive phase of lead oxide is detected in the one before exposure to water vapour. According to temperature dependence of resistivity measurement results, samples beforeexposure to water vapour have superconductivity behavior belowcritical temperature (Tc final =100K) and conducti...

Water purification technology based advanced oxidation processes emerging ozone

The growing demand for fresh water is partially satisfied by desalination plants that increasingly use membrane technologies and among them advanced oxidation processes emerging ozone to produce purified water. In this research, the water purification technology using advanced oxidation processes emerging ozone to be able to eliminate the content of humus acids and organic compounds is developed. The laboratory test for three different sample of peat water indicated that the water purification still contaminated with high organic matter with pH less than 7. It can be concluded that the proposed method still require an extended processing to produce consumable water.