Applied Mechanics and Materials Vols. 341-342

Abstract: Super-hard tool material is a main research point of mechanical engineering because of excellent performance. The development of technology for high-speed cutting process could enhance the machining quality and surface precision. It is a difficulty thing to get higher finished surface for traditional machining process. However, the super-hard cutter material could enhance the finished performance of tool material. For example, the wearing resistance, high stability of PCD (polycrystalline diamond) and PCBN (poly cubic boron nitride) can get more information for obtaining higher finished surface quality. The author introduces super-hard cutters materials (PCD and PCBN) development, and discusses several material properties. The features of materials used in different cutting fields are discussed.

Abstract: PI film was suspended in NaOH, FeCl₃ and EDOT solutions sequentially. The surfaces of the films were analyzed with ATR-FTIR and the surface resistances were measured in four-probe mode. After immersed in NaOH solution amic acids were introduced to the film surface. The hydrolyzed film exhibited better adsorbing property and was able to adsorb FeCl₃ in g/m² magnitude. As the film with adsorbed FeCl₃ was suspended in EDOT solution EDOT deposited on the surface and converted to conducting PEDOT. The resultant film exhibited surface resistance about 10⁵ Ω and the characteristic absorption bonds of PEDOT on FTIR spectrum.

Abstract: CO₂ solid adsorbent was prepared through impregnating acrylonitrile (AN) modified monoethanolamine (MEA) into structurally disordered mesoporous silica (M) pore channel. Its structure was characterized by X-ray diffraction characterization (XRD), N₂ adsorption-desorption tests (BET), Transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR). The capacity of CO₂ adsorption and desorption were measured and evaluated by comparison with MEA-impregnated material. The results showed that the capacity of M-MN-50 reached up to 125.8 mg·g^-1 and could desorb completely at the temperature of 40 °C by vacuum with 2.6 KPa. The hybrid material exhibited satisfactory performance during 10 turnovers.

Abstract: Cu-20Ni-5Sn alloy has not only high content of Ni melted point 1453°C, but also low melting point elements of Sn melted at 231.9°C, therefore, the grain structure of alloy as-cast is in perfect dendrite that lends to form segregation and inverse segregation of Sn, so that the hot rolling (cogging) processing is restricted. The influence of casting methods, cooling rate and heat treatment on the microstructures and properties of as-cast Cu-20Ni-5Sn alloy were investigated. The results show that, compared to the ingot casted in iron mold and graphite mold, the microstructure of Cu-20Ni-5Sn ingot prepared by horizontal continuous casting is the finest and the Sn segregation level is in lowest. The microstructure of the ingot casted in graphite mold is in the most perfected dendritic and with the highest segregation of Sn, the microstructure of ingot in iron molding is in the middle. The ingots must be homogenized before cold-processing. Homogenization treatment can eliminate Sn segregation and dissolve the non-equilibrium phase of ingots.

Abstract: Investigating the electrochemical corrosion behavior of Cu15Ni10Mn alloy in NaCl solution with different Cl concentration was studied by measuring open-circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry. The results show that as the Cl^- concentration increase, the corrosion potentials of the alloy shifted negatively, corrosion currents increase, the corrosion process by electrochemical control change of diffusion control, and therefore the corrosion rates become faster. The presence of Cl^- have effect on the dissolution mechanism and corrosion products of the alloy, when the concentration of Cl^- is relatively low, a reducing peak current appears in the process of cyclic voltammetry retracing , when the Cl^- concentration is higher, cyclic voltammetry flyback process does not appear to restore the current peak. This is mainly associated with the generation of corrosion product, when Cl^- concentration is low, the corrosion product is Cu₂(OH)₃Cl (basic copper chloride) and other two copper ion salts, when the concentration of Cl-is higher, corrosion products are mainly Cu₂(OH)₃Cl (basic copper chloride).

Abstract: Response surface analysis was applied to optimize the processing of preparing the heat-resistance of the cotton stalks bast fiber reinforced PLA composite. Effects of all factors were evaluated and three factors were selected, which were addition of TAIC, mass fraction of fibers and length of fibers. Subsequently, response surface analysis based on Box-Behnken experimental design was employed to evaluate the interactive effects of three factors. One mathematical model for the processing of composites as functions was established. The results showed that the optimal processing was that the addition of TAIC was 2.1%, the mass fraction of fibers was 26.7%, the length of fibers was 11.7mm, and the HDT of composite was 161.39°C. Under the optimal conditions, the true value was close to the predicted value.

Abstract: The physi-mechanical performances of geosynthetics were studied by the test on the geosynthetics produced by one factory. Tests of stretching, top-breaking, pierce, tearing, etc. under different materials, temperatures and moistures were done by indoor study, thus studying the physi-mechanical performances of geosynthetics under different conditions. The research shows: the stretching performance of nonwoven textile is better than the woven textile's; The influence of temperature on the geosynthetics is remarkable, it should be emphasized during the construction; The moisture has a little impaction on the mechanical performance of geosynthetics; These achievements provide scientifical data and references for the physi-mechanical performances of geosynthetics, while no further study on the long-term effect, it should be studied in future.

Abstract: Electric flocculation was a kind of wastewater treatment-cleaning technology. The fundamental principle of electrocoagulation and the application for wastewater treatment of eIectrocoagulation were reviewed.

Abstract: Fast-growing poplars are used as test materials in this study, which are respectively first carbonized then impregnated treatment and carbonized treatment, to test the dimensional stability of modified wood. The results show: the shrinkage rate of specimen which is first carbonized then impregnated is higher than the control group as much as 87.80% ~ 89.16% in radical direction, 76.20%~82.43% in tangential direction; from oven-dry state to air-dry state, the swelling rate of specimen is higher than the control group as much as 5.26% , 9.09%, and to saturated state, the rate is lower than the control group as 14.55% and 0.13% respectively in radical direction and tangential direction, as a result, the characters of shrinkage and swelling are not improved. When carbonized, the shrinkage rate of specimen is lower than the control group as 3.01%~8.47% and 5.08%~5.86% respectively in radical direction and tangential direction; the swelling rate is lower than control group as 23.84%~41.05% and 12.01%~43.75% respectively in radical direction and tangential direction, as a result, the character of shrinkage is poorly improved but swelling is obviously improved. After the two modified treatments, moisture absorption rate is respectively 6.99% and 4.91%, both lower than the control group8.80%; moisture resistance rate respectively 20.57% and 44.20%; water absorption rate 107.27% and 123.74%, lower than the control group 210%; resistance to water absorption up to 48.92% and 41.08%. Know then, carbonization treatment is better in terms of the affect on improving dimensional stability of wood.