Abstract: The development of environment-friendly water-based lubricants has been paid more and more attention in modern manufacturing due to environmental concern and human health. In this paper, several water-soluble molybdenum-containing additives (WMCAs) were synthesized, and characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The tribological properties of WMCAs in water were evaluated by a four-ball tester. The results indicated that WMCAs exhibited beneficial effect on the anti-wear and friction-reducing properties of water under all tested concentrations, which could be attributed to organic nitrogen compound, iron oxides and MoO3 in WMCAs tribofilm.
Abstract: The sizing agent is made by polypropylene powder in blending method and then sizing the warp with it. The result of its sizing performance shows that the sizing capacity of the newly made sizing agent could meet the requirement of waving property compared with the traditional sizing agent. The composite material is made by Glass fiber texturized yarn cloth as reinforce materials after the weaving is completed. And, subsequently, test the properties of the composite material. Result shows that the properties of the composite material which is processed by polypropylene powder slurry have been improved, compared with the composite material processed by traditional slurry. The use of new slurry can remove the calcine process. Therefore, it will save energy and reduce the pollution.
Abstract: The uniaxial tensile creep tests of the double-base solid propellant specimens were carried out at 450C under five different stress levels. The viscoelastic models such as three parameters solid model, Burgers model, generalized Kelvin model, five parameters solid model and exponential model were adopted. The computation equation that can describe the strain rate of the second creep stages of the double-base solid propellant under different applied stress levels was founded on the basis of these creep tests, and the adaptability of the five models on creep characteristics of the double-base solid propellant were studied. The study results shows that the five models can show good agreement with second creep course of propellant under different applied stress levels, but the generalized Kelvin model may have optimal characterize creep curve of the double-base solid propellant.
Abstract: Two groups of 304 stainless steel samples different in thickness were prepared by Laser Prototyping, one of which was treated by high-frequency micro-forging. The residual stress on the sample surface was measured by strip cutting method. The results showed that the surface residual stress of the samples was tensile stress, which increased with thickness, and the residual stress began to drop while the thickness of samples arrived at a certain value. Therefore high-frequency micro-forging could regulate the surface residual stress state of the samples. Specifically, micro-forging could transform the tensile stress into compressive stress, which rose with the increase in thickness of samples and tended to be stable afterwards.
Abstract: Zn and Fe nanoparticles prepared by the arc was used in the present study. It were oxidized by laying in the air The microsturctures, oxygen content and oxygen atoms position in nanoparticles were investigated. The results showed that the effective size of oxidized nanoparticles was about50-100nm, particles with a complete form, Particle radius and dislocation density of Oxidated Zn nanoparticles have not change much compare with Zn nanoparticles.Only the strain increase. Fe nanoparticles oxidation lead particles strain rising sharply, and the dislocation densities have decreased slightly. the oxidation occurs in the surface of Fe nano-particles, and generated Fe2O3, After Zn nanoparticles oxidized,Formed ZnO Particles on the surface.
Abstract: In this paper, polypropylene (PP) melt blown non-woven fabric is treated by atmospheric pressure N2 or N2/O2 dielectric barrier discharge (DBD) plasma. The variation of the surface hydrophilicity of PP sample is experimentally investigated by surface water contact angle, Fourier transform infrared reflectance spectroscopy (FTIR-ATR). The results show that the hydrophilicity of PP sample is considerably improved as long as the very short plasma treatment time (several seconds). However, the treatment effect of atmospheric N2/O2 plasma is worse than that of atmospheric N2 plasma early in the processing (0-7s). But the treatment effect of atmospheric N2/O2 plasma obtains improvement increasing the treatment time (>7s).
Abstract: Composites of continuous aramid fiber reinforced impact polypropylene copolymer (IPC) were prepared using a cross-head impregnation mold by self-design fixed on a single screw extruder, and pelleted by a pelleter for injection molding to prepare testing specimens. The mechanical properties of long aramid fibers reinforced impact polypropylene copolymer (IPC) composites were studied. Micrographs of fracture surface of tensile specimens and dynamic mechanical behavior for the composites were analyzed by scanning electron microscope (SEM) and dynamic mechanical analyzer (DMA). The results of experiments show that, the tensile and flexural strengths increased obviously with the aramid fibers content in the composites. SEM results show the compatibility between the aramid fiber and matrix is very poor. The results of the dynamic mechanical behavior of long aramid fibers reinforced IPC composites show that the composite deformation resistance and glass transition temperature increased evidently with the addition of aramid fibers.
Abstract: To research and analyze the additional stress distribution and change of granular materials, the model tests are used to observe vertical additional stress in different position and depth. And the comparison between observed values and theoretical values is conducted to analyze the transmission and attenuation of additional stress in granular materials. The research results show that calculated values are based on Boussinesq solution which ignores the property of soil layer (materials), the distribution of additional stress for fine sand which belongs to granular materials is largely deviated from theoretical value. For granular materials, inner friction structure effect is evident influence to additional stress transfer. And continue using calculation method which is based on continuum materials will have bigger difference and even wrong.
Abstract: Glass transition temperature is an important thermal property for polymer materials. When its temperature exceeds this temperature, the exhibiting characters dramatically changes. Although the experimental techniques suited to this temperature measurement are well-established, the full-field optical measurement method has not been employed to characterize this property. Therefore, this paper aims to measure the glass transition temperature using optical method.
Abstract: As a kind of corrosion resistant material, stainless steel is widely used in petroleum, chemical, pharmaceutical. Stress corrosion cracking is a main reason that why the stainless steel became disabled. Therefore, it is very necessary to research and study the stress corrosion cracking of stainless steel .The failure analysis to the sample is conducted aiming at the stress corrosion of the stainless steel piston cylinder in a factory. The analysis includes macro analysis, metallographic observation, scanning electron microscopy analysis and XRD analysis. The results of the study show that it is nonmetallic inclusion on the grain boundary, the chloridion in the industrial circulating water and the rough columnar austenitic grains in the organization of the samples that lead to the stress corrosion cracking of the piston cylinder.