Materials Science Forum Vols. 510-511

Abstract: An asymmetric polysulfone membrane with reactive group of –OH was obtained by hydrolyzing the chloromethylated polysulfone membrane, and the albumin molecules were immobilized into the membrane with a crosslinking reagent of 1,4-butanediol diglycidyl ether. The albumin-fixed membrane was used to remove lipophilic toxins, bilirubin, from the bilirubin-albumin solution. The experiment results showed that the transfer rate of bilirubin was clearly enhanced after fixing albumin into the hydroxylated polysulfone membranes. The clearance of bilirubin was 49.3%. In addition, the effect of membrane thickness on the removal of bilirubin is discussed.

Abstract: This paper investigated the effects of anodizing time on the formation of anodic oxide films on a Mg-Al alloy in alkaline solution. The thickness of the anodic oxide film was increased by increasing the time required to generate the active dissolution reaction. When anodizing at various anodizing time, the potential after passivity increased with time, which implies growth in film thickness. When the anodizing time was varied, the quantity of oxygen increased with time in the white areas (the film), i.e., more film was observed in the SEM and EDX analyses.

Abstract: To enhance high power characteristics for piezoelectric transformer, an alloy design approach in PZT base ceramic system was considered. Various Zr/Ti ratio compositions in 0.03Pb(Sb0.5Nb0.5)O3- 0.03Pb(Mn1/3Nb2/3)O3-(0.94-x)PbTiO3-xPbZrO3 (0.445
x
0.475 mol)[PSN - PMN - PZT] system were synthesized by the conventional bulk ceramic processing technique. To improve high power characteristics at their morphotropic phase boundary (MPB) composition of PSN-PMN-PZT system, various spectra of Zr/Ti ratio were systematically experimented, and their effects on the subsequent piezoelectric properties and dielectric properties for high power piezoelectric transformer application were investigated using an impedance analyzer and a laser vibrometer. Microstructure and phase information were characterized using X-ray diffractometer (XRD) and a scanning electron microscope (SEM). When the Zr/Ti ratios were 0.475/0.465, the mechanical quality factor and electromechanical coupling factor were shown to reach the maximum, indicating that this alloy design can be a feasible composition for high power transformer.

Abstract: Lotus-type porous magnesium with a large number of unidirectional cylindrical pores was fabricated by unidirectional solidification of melt dissolving hydrogen in a pressurized hydrogen atmosphere. The vibration-damping capacity of the lotus-type porous magnesium plate which has many open pores was measured in this work. The attenuation coefficients of the free vibration of lotus-type porous magnesium were measured by hammering-vibration-damping test, which revealed that the attenuation coefficients increase with increase in porosity; the damping capacity of lotus magnesium is higher than that of non-porous magnesium. The mechanism for high damping capacity was analyzed on the basis of the Fourier transform technique, which indicates that various vibration modes of high frequency are observed. The excited vibrations of high frequency enhance the damping capacity of lotus-type porous magnesium.

Abstract: Mechanically induced crystallization of an amorphous Fe90Zr10 alloy was studied by means of X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Under high-energy ball-milling in an AGO-2 mill, melt-spun Fe90Zr10 ribbons undergo crystallization into BCC α- Fe(Zr). Zr atoms are found to be solved in the Fe(Zr) grains up to a maximum supersaturation of about 3.5 at.% Zr, where it can be presumed that the remaining Zr atoms are segregated in the grainboundaries. The decomposition degree of the amorphous phase increases with increasing milling time and intensity. It is proposed that the observed crystallization is deformation-induced and rather not attribute to local temperature rises during ball-collisions.

Abstract: Symmetrically and unsymmerically substituted bis-dithiobenzil nickel complexes containing four substituted and unsubstituted methoxy groups were synthesized from a benzoin compound using phosphorous pentasulfide under the conventional thermal and microwave processing. The efficiency of microwave synthesis over the conventional thermal synthesis was illustrated by the yield of bisdithiobenzil nickel complex dyes. The samples were characterized by the means of elemental analyzer, 1HNMR, IR spectroscopy, Uv-vis spectroscopy and DSC.

Abstract: Nanocrystalline nickel powders were prepared by chemical reduction of nickel chloride hydrate with different surfactant at moderate temperature in a pressurized vessel. Nickel nanosheets were generated successfully through reducing the nickel ion complexes, formed by sodium tartrate, at alkaline condition by hydrazine hydrate. The nanosheets and nanowires were characterized by the means of an X-ray diffractomer (XRD), a field emission scanning electron microscopy (FESEM), an energy dispersive X-ray spectrometer (EDS) and a high sensitive magnetometer (HSM).

Abstract: Nanosize nickel powders were successfully produced by electrical explosion of wire (EEW). In EEW, the nickel wire was discharged in a chamber filled with nitrogen or argon gas, and the produced powders were subsequently stabilized by air-passivation at room temperature for 2 h. X-ray diffraction only showed the nickel phase of FCC crystal structure, whereas TEM and XPS analyses showed the formation of a very thin oxide layer of NiO on the surface of particles. Particles were spherical in shape, and the mean particle size calculated by specific surface area was about 100 nm. The particle size decreased with increasing charging voltage and with increasing ambient gas pressure. Argon gas was more effective in producing finer particles than nitrogen gas.

Abstract: Kenaf bast, coconut coir, and cotton, which are lignocellulosic fibers and environment friendly natural materials, were tested for their ability to remove copper, nickel, and zinc ions from aqueous solutions according to their physical and chemical changes by solvent extraction. The order of the lignin and xylose content in unextracted fibers is coconut coir>kenaf bast>cotton. The fiber with the highest level of heavy metal removal, however, was kenaft bast. It showed that removal of heavy metals does not correlate with lignin and xylose content. Cotton, with about 1.1% lignin and 0.3% xylose, was very low in heavy metal ion sorption while other two fibers containing lignin and xylose did remove heavy metal ions. It indicates that lignin and xylose play a role in heavy metal ion sorption. Extraction with the various solvents removed different cell wall components and changed the cell wall structure, and thus did change the heavy metal ions removal capacity of lignocellulosic fibers.

Abstract: Urban runoff is one of the major sources that contaminates water supplies because it contains toxic compounds such as heavy metals and PAHs (poly aromatic hydrocarbons) as well as suspended solids, organic compounds, and nutrients. The eingineered polymetric media in this research were developed as filtering media in the storm water treatment equipment. The media used in this study can remove contaminants in urban runoff via adsorption and filtration. The engineered media composed of polypropylene and anion surfactant were foamed to have buoyacy and then shattered by mechanical device for efficient filtration. Surface characteristics of the engineered media were determined by using a scanning electron microscope and a microscope. Results indicated that surface area of the engineered media were increased from less than 0.05m2/g for the neither foamed nor shattered media to 7.82m2/g for the foamed and shattered media. Specific gravity of the media that were foamed and shattered was 0.108~0.154 whereas the non-treated media had specific gravity of 0.914. Fractal dimension of media was measured for the irregularity of the media shape and the media that had high fractal dimension value was performed high filtration efficiency of suspended solids in runoff.