Abstract: In the paper, the relationship between the grain size and fatigue life are studied. To specify the initial and short crack propagation life of low carbon steel material, three methods are used in the simulation. At first, the K. Tanaka’s model is introduced to calculate the fatigue life of a grain. Then, the Voronoi Diagram is used to generate the microstructure of grains. At last, a criteria to specify the short crack is proposed. Based on these methods, the numerical simulation is conducted. With the help of the process, the grain sizes are generated randomly in order to specify how grain sizes effect fatigue life. The computational results are in good agreement with the experimental data. The results show that the randomness of fatigue life is closely related to the randomness of grain sizes.
Abstract: The EVP model is an available method to apply to the vertical settlement of soft soil consolidation calculation and analysis. Compared with Visco-Plasticity model, it shows more consistent with the actual stress conditions of the soil. In this paper, We have extracted soil samples in BinHai garden for assay. Then through the comparison with calculating results and a long-time engineering monitoring in BinHai garden soft soil area, a feasibility EVP model study on the vertical settlement in soft soil area is peoposed. Further a consequent sedimentation forecast was made according with the EVP model calculation. In the end, the settlement influence from creep was analyzed through one-dimensional consolidation theory.
Abstract: The bedding rock mass is a common geological configuration in earthquake engineering, and the wave method is often used in seismic response analysis, but the accuracy of the analysis is restricted because of the viscoelastic boundary parameters can only be take approximate values. In order to select the most reasonable approximation of boundary parameters in the analysis, in this paper, based on the transversely isotropic constitutive relation of the bedding rock mass, the existing methods of spring coefficients and damping coefficients are compared and analyzed, and the suggestion for the approximate values of the viscoelastic boundary of the bedding rock mass is given.
Abstract: Facing the cement and concrete development process, reducing greenhouse gases and the consumption of natural resources has become an important issue. To reduce the cement content in concrete, the increased use of concrete combining large amounts of industrial by-products is expected. Ground granulated blast furnace slag (GGBFS) has been used as a supplementary cementitious material in ordinary Portland cement (OPC) concrete. In this study, GGBFS at different cement replacement ratios of 0%, 20%, 40%, and 60% by weight were used to produce concrete. Compressive strength test, water absorption, electrical resistivity, and rapid chloride penetration test (RCPT) were performed to investigate the effect of GGBFS on compressive strength and durability of concrete. Test results show that GGBFS concrete with 40% cement replacement (G40) has the highest compressive strength. The water absorption and chloride permeability reduced with the increasing cement replacement percentage by GGBFS. Meanwhile, the electrical resistivity increased with an increasing GGBFS replacement percentage. Based on the results, GGBFS concrete with 40% cement replacement seems to be the optimum replacement in this study.
Abstract: Struck axle is a critical component of truck that bears the auto-body weight and load weight. Fatigue life safety is the primary consideration in the design process of axle. With the development of environmental protection concept of energy saving and emission reduction, lightweight design of vehicles becomes more and more urgent. It has been becoming a mainstream trend for design to ensure both safety and significantly reduce the weight of axle. Based on the basic truck axle structure design, revised designs with thickness-reduced were proposed to reduce the weight of truck axle .Both basic and modified design were modeled using Abaqus 3D software to calculate the stress and strain contours in the case of vertical load and axial torque, then fatigue life contours of models for each load case were calculated with the help of Brown-Miner biaxial fatigue theory. It was shown by the research that topology-optimization of truck axle, under a premise of qualified fatigue life and stiffness required by customers, can reduce the weight of two kinds of truck axles by 15.3% and 18.1% respectively.
Abstract: In order to improve wear resistance surface on 0Cr18Ni9Ti stainless steel, Cu coating on the 0Cr18Ni9Ti stainless steel substrate was deposited by electroplating technology. The friction and wear properties of 0Cr18Ni9Ti stainless steel substrate and Cu coating were investigated contrastively. The morphologies of the wear scars were analyzed by scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDS) and scanning probe microscope (SPM), and the wear mechanism was discussed. The results showed that the wear resistance of Cu coatings was significantly improved as compared to that of 0Cr18Ni9Ti stainless steel substrate. The wear scar of 0Cr18Ni9Ti stainless steel substrate showed flaking pit, and its wear mechanism were delamination and abrasive wear. In case of Cu coating, the wear scars showed morphology of plastic deformation caused by adherent copper debris being pressed, and its wear mechanism were delamination and fatigue wear.
Abstract: A new antibacterial acellular dermal matrix (AADM) dressing can not only resist infection, but also accelerate wound healing. AADM was prepared by SDS (0.40%), trypsin (0.40%) and keratin (0.30%), and then cross-linked with carboxymethyl chitosan (1%) with glutaraldehyde, whose tensile strength (MPa) is 10.66, thickness (mm), 0.53, the rate of permeable steam (g • m-2 • 24h-1), 3640, porosity (%), 81, degradation time in vitro (h), 24.33, pH, 6.5, and the average inhibition rate, more than 70%. At the same time, scanning electron microscopy showed that the structure of AADM was evacuated and the pores were interconnected. On such basis, a conclusion was drawn: the properties of AADM has been sharply increased, compared with acellular dermal matrix, which cannot resist infection, and the new antibacterial acellular dermal matrix completely meets the clinical requirements for burn dressings.
Abstract: Sugarcane bagasse is an agricultural waste that is potentially used as natural silica resources. Natural silica claimed to be safe in handing, cheap and can be generate from cheap resource. In the objectives of this study were to prepared silica from Sugarcane bagasse. The preparation of Sugarcane bagasse ash by burning at 700 °C for 4 and 6 h, respectively in atmosphere. The result of X-ray florescent: XRF, silica content which was obtained after heat treatment at 700 °C for 6 h was 80.814 wt%. Bagasse ash was purified by alkaline extraction method with 1.5, 2 and 2.5 N sodium hydroxide (NaOH), respectively. And refluxed by using concentrated 2 N sulfuric acid. From X-ray diffraction pattern showed that the obtained products were amorphous silica, 2.5 N sodium hydroxide. The morphology was observed by SEM, sphere and average particles dimension of synthesis silica with 1.5, 2 and 2.5 N NaOH are 120, 100 and 80 nm respectively. The SEM micrographs showed that the Concentration of NaOH was increased, the particles dimension decreased
Abstract: Five PEDOT:PSS:MoO3 volume ratios (1:1, 1:2, 1:3, 1:4, 1:5) hybrid hole transport layer (HTL) were prepared by solution processed method. The cell structure was PET/ITO/PEDOT:PSS:MoO3/P3HT:PCBM/Ca/Al. We investigated the effect of MoO3 added into the traditional PEDOT:PSS hole transfer layer on the photovoltaic performance. From these results, we found that the short circuit current density (Jsc), fill factor (FF) and power conversion efficiency PCE of the cells with MoO3 are always higher than those of cell without MoO3.The short-circuit current density, fill factor and power conversion efficiency of cells increased with increasing MoO3 volume ratio from 1:1 to 1:3 and then decreased slightly when the volume ratio increased to 1:4 and 1:5. The cell with 1:3 volume ratio exhibited the highest Jsc of 9.41 mA/cm2, an increase of 22%, and the highest PCE of 2.74%, an increase of 39%, compared to the controlled cell using PEDOT:PSS layer. The addition of MoO3 increased the probability of exciton dissociation due to its high hole mobility, thereby enhancing the Jsc and FF.