Advanced Materials Research Vols. 79-82

Abstract: In this paper, a 20nm inorganic mineral particles, mainly includes Mg3Si2O5(OH)4, KAlSiO4 and CaMg(CO3)2, were prepared by the ultrasonic nanometer grinder. As a lubricating oil additive, the dispersion property of the particles was characterized and the tribological properties were evaluated. The antiwear mechanism was investigated with SEM, EDS and XRD. Results show the inorganic nano-mineral material as an oil additive has excellent stable-dispersion property. The load-carrying capacity and antiwear property of the base oil were improved greatly. It can be inferred that the additive creates certain deposit on the friction surface. The physical-chemical deposition could not only bear the load but also prevent forming direct contact of two rubbing surface. 0.5wt% is the optimal additive concentration.

Abstract: We present the synthesis of carbon nanocoils using the chemical vapor deposition technique with metal catalysts on silicon substrates. The optimum synthesis conditions and coil geometry are summarized. The coils have distribution of the outside diameter of 300 nm to 1200 nm, wire diameter of 150 nm to 400 nm and the pitch of the coil of 150 nm to 1200 nm. Applications of the developed carbon nanocoils can be electro-mechanical sensing and the electro-magnetic insulation.

Abstract: The concept of the fiber reinforced polymer (FRP)-concrete composite design was exploited in a new type of bridge superstructure. The proposed FRP-concrete composite bridge superstructure is intended to have durable, structurally sound, and cost effective composite system that will take full advantage of the inherent and complementary properties of FRP material and concrete. As a trial case, a prototype bridge superstructure was designed as a simply supported single-span one-lane bridge with a span length of 10 m. The bridge superstructure consists of two bridge decks and each bridge deck is comprised of four FRP box sections combined with a thin layer of concrete in the compression zone. A test specimen, fabricated as a one-third scale model of the prototype bridge superstructure, was subjected to four-points loading to simulate the two heaviest axles of the Chinese design truck load. The test results indicate that the proposed bridge model meets the stiffness requirement and has significant reserve strength.

Abstract: Composite I-shaped beams are currently used in aerospace, ocean and civil engineering applications. Increasing the vibration damping of composite structures is a concerned need in those applications. This research is an effort to investigate the damping performance of composite I-shaped beams with cocured viscoelastic damping layers using finite element method and modal testing technique. A hybrid finite element model for a damped composite I-shaped beam was developed. Modal strain energy method was used to estimate the linear viscoelastic modal loss factors of the composite beams. A numerical parametric investigation was conducted to study the effects of various parameters on the dynamic properties of composite beams under free-free end boundary condition. Selective design parameters included inserting location and thickness of damping layers. Natural frequency and modal loss factor were also extracted by experimental modal analysis. Static tests were performed to obtain the loss of static stiffness for inserting soft viscoelastic layers. Experimental and analytical results show the inserting location of cocured damping layers has significant effects on the damping and there exists a critical damping layer thickness for optimal damping with less significant modal frequency decrease. Static tests results demonstrate a little loss of static stiffness for embedding low module damping layers. A careful selection of damping layer location and thickness is needed to optimize the damping benefits desirable and the mechanics stiffness reduction that can be tolerated for intergral damping composite structures.

Abstract: In this paper, the author does research on the surface modified of nanometer ZrO2/SiO2 composite and makes it a good dispersivity in organic solvents. As lubricating oil additive, added it into the base oil with different concentration. Anti-wear and reducing friction performances measured by the four ball test and the thrust-ring tribotester. The results showed that the average friction coefficient decreased 21.14%, the weight lost of the thrust-ring was no wear or negative wear when the additive concentration was 1wt%. The worn surfaces were quite different compared without additive, the grooves formed during the friction experiment become smooth and finally a narrow wear scar. There were many white particles and dimples on gray surface, the white particles were higher than those of gray parts. The white particles was ZrO2/SiO2 composites according to EDS and XRD analysis. The Si and Zr elements appeared on the worn surfaces can not be cleaned out in petroleum ether and ultrasonic ambiance, this is a dynamic self-healing mechanism .

Abstract: A novel route for synthesis of biomorphic nickel oxide （NiO） hollow microspheres, using yeasts as bio-templates, has been successfully developed. In the typical process，yeast cells were first coated with nickel hydroxide and then calcinated to obtain nickel oxide hollow microspheres. As-prepared products were characterized by DTA, SEM, XRD and FTIR. A possible formation mechanism of NiO hollow microspheres was proposed in brief.

Abstract: The microstructures characteristics of interface and wear resistance Of ZnAl27 composite reinforced by SiC particles have been studied by means of SEM and HRTEM. The results shown that SiC particles could be distributed in ZnAl27 alloy uniformly, and the excellent combined interface between SiC particles and ZA27 matrix is formed. CuZn4 could nucleate on SiC particles and grow up at higher speed along SiC particles than at the vertical direction. The wear resistance of the ZnAl27 alloy could be increased remarkably due to the addition of SiC particles. When the SiC particles are added to 30％, the wear resistance was raised by 126.5 times

Abstract: Cuprous oxide(Cu2O) microcrystals were successfully synthesized via hydrothermal method using CuSO4•5H2O and Na2SO3 in HAc-NaAc buffer solution. The products were characterized by X-rays diffraction (XRD) ,scan election microscopy (SEM) and ultraviolet-visible (UV-vis) spectroscopy. The photocatalytic activity of the as-prepared Cu2O powders was evaluated by the photocatalytic degradation of methyl orange solution under visible light irradiation at room temperature in air. The effects of chlorine ion on the photocatalytic activity of the Cu2O powders were investigated and discussed. The results show that chlorine ion in solution can obviously decrease the photocatalytic activity of Cu2O. When the concentration of chlorine ion increased to 0.5mol/L(about Cl- concentration in the seawater), the photocatalytic ratio of Cu2O decrease to 45% compared with the value in pure water. Increasing solution pH can enhance the photocatalytic activity of Cu2O. The mechanism of photo-degradation was discussed.

Abstract: Pd/Fe bimetallic catalysts were synthesized via chemical deposition and used to eliminate chlorine compacted in shellac while it was being bleached with sodium hypochlorite in alkaline solution for the preparation of low chlorine shellac, a natural and biological product used in large scale in food industry and pharmaceutical fields. Experiments demonstrated that the Pd/Fe bimetallic particles could catalyze dechlorination process effectively, which was affected by several factors such as reaction temperature, Pd/Fe ratio, and the induction of Pd/Fe. The dechlorination efficiency reached 81.9% under the conditions of Pd/Fe loading ratio of 0.10wt%, binary metal usage 10 g/L, H2 flowing rate 50 mL/min, and reaction temperature 90°C for 240 min. Moreover, the mechanism of catalytic hydrogenation was elucidated through structure characterization of the final products using elementary analysis, infrared spectroscopy, and ultraviolet spectrophotometer. It was shown from the result of ultraviolet spectrophotometer that the wavelength of the maximum absorption of seedlac, the raw materials for obtaining shellac, was 235 nm. However, it was blue shifted to the same value 222 nm when the shellac was dechlorinated by catalytic hydrogenation with Pd/Fe binary metal particle as the shellac without catalyzed. The results of elementary analysis showed that chlorine content in the final product was only 0.46%, just 1/5 comparing to that of non-declorination by catalytic hydrogenation under the optimum conditions. It was shown that the chlorine ions compacted in the shellac was substituted by hydrogen ions.

Abstract: In this study, a novel NH2-functionalized nano-sized magnetic polymer (TEPA-NMP) adsorbent coupling with tetraethylenepentamine (TEPA) had been prepared. Its application for the removal of Cr(VI) from industrial wastewater was investigated. Batch adsorption studies were carried out to evaluate the effects of pH value, initial concentration, adsorption isotherm, adsorption kinetics, and desorption characters etc. The adsorption of Cr(VI) reached equilibrium rapidly within 30 mins. The adsorption efficiency of the TEPA-NMP on Cr(VI) was dependent on pH value and the initial Cr(VI) concentration. The adsorption efficiency of Cr(VI) decreased with the increasing of the initial Cr(VI) concentration and pH value. The adsorption data were well fitted with the Langmuir isotherm. The maximum adsorption capacity calculated from the Langmuir isotherm was 370.4 mg/g at temperature of 35 °C and pH of 2.0. Regeneration studies indicated that the adsorbent could be reused for 8 times with only 3.4 % lost of adsorption efficiency. The adsorption mechanism study results suggested that the adsorption of Cr(VI) could be related with electrostatic attraction, ion exchange and coordination interactions.