Abstract: The study reports the sintering kinetics of Ti–48Al–2Nb-2Cr composites (TANC) with addition of different weight contents of LiF, NaF,CaF2 and 38%CaF2-62%BaF2 eutectic solid lubricant (BC) using OM, SEM and DSC. The microstructure of TANC composites with different CaF2 and BC content is analyzed. Additions of solid lubricants to TANC matrix have significant influences on densification degree of the composites. Densities increase with sintering temperature and time, decrease with addition amount of solid lubricant.
Abstract: Experiments were conducted to study the workability of fresh concrete and basic mechanical properties of hardened concrete with gravel-crushed proto-machine-made sand. Effects of water to cement ratio and content of stone powder were mainly considered. Based on the test and before, the values of practical parameters in formula are obtained for calculating mixed strength of concrete, and the beneficial range of water to cement ratio is proposed. Meanwhile, the reasonable water content, sand ratio and content of stone powder are also suggested.
Abstract: Using aluminum sulfate as precursor and urea as precipitator, hollow sphere boehmite was synthesized by hydrothermal treatment on 140°C for 24h. The time effect of as-synthesized product was studied by XRD, SEM and TG, et al. The results show that with the hydrothermal time increasing the product’s phase transformed from sodium sulfate aluminum to amorphous form to mixture phases of sodium sulfate aluminum and boehmite to boehmite. After 24h hydrothermal treatment, the product can completely change to boehmite. With the hydrothermal time increasing, the micromorphology of hydrolysis product experienced the evolution of smooth dense globe to core-shell sphere to hollow sphere.
Abstract: Studied the hygroscopic properties of a molded combustible cartridge case by weighing method. Investigated residue formation of cylinder materials with different water content by nitrogen-bomb tests. The results show that the higher the relative humidity, the greater the equilibrium moisture content of the inside-wall material. When the relative humidity was about 90%, its absorption rate was about 5.4%. Compared with its outside wall, the inner parts have much stronger moisture absorption properties. The combustion remains grew in quantity generally with the increase of moisture content.
Abstract: With the increasingly aging societies coming, as a service robot, the mobile humanoid robot is worth making efforts to study. This paper mainly introduces the developing status of the mobile humanoid robot. The characteristics of five robots are presented. Key technology of the mobile humanoid robot is pointed out, and the problems needing further research are discussed.
Abstract: Basing on the new developed direct shear testing instrument and the tri-axial test instrument with large scale specimen, the shear strength parameters of municipal solid waste has been studied. The municipal solid waste is divided into three parts: the material that is easy to be biodegraded, reinforced material that is difficult to be biodegraded and the incompressible solid waste material. The proportions of these three parts are selected as 80%, 5% and 15%, respectively. A series of laboratory tests have been performed for different initial void ratios, different vertical pressures and different confining pressures applied on the test specimen. Testing results show that the initial void ratio is the main influence factor for the shear strength parameters of the municipal solid waste, the relationship between the shear stress and the shear strain is a strain hardening curve, the shear stress increases gradually with the shear strain. Besides, the principle effective stress increases with the axial strain and the confining pressure in a hardening increasing trend, and the principle effective stress decreases with the increase of the initial void ratio of the municipal solid waste. The shear strength shows a linear relationship to the vertical pressure applied on the test specimen, and it is in accordance with the law of coulomb. According to the testing results of the direct shear test and the tri-axial test, the shear strength parameters are obtained. The cohesion varies from 4.7 to 12.2kPa, and the internal friction angle varies from 14.5 to 28.2 degree.
Abstract: The fibrous materials made from collagen have some shortcomings, such as its mechanical property, water-resistant and thermal-stability. So the mixture is produced by blending collagen with chitosan at different mass ratio. Theirs mechanical, water-resistant and thermal-stability properties of these blending mixtures are characterized by FT-IR, DSC etc analyzing methods. These results indicate that the properties are improved great. Furthermore it obtains that the optimal ratio of collagen to chitosan is about 20:80.
Abstract: Phase-field method can be used to describe the complicated morphologies of crystal growth without explicitly tracking the complex phase boundaries. The conformation of volume free energy is very important for microstructure simulation with phase-field method. However, the conformation of volume free energy is still correspondingly simple and ideal at present. In this paper, a new conformation method of free energy is mentioned. Free energy of each phase at appointed states is calculated by Thermo-Calc software. In order to avoided calculation, free energy of each phase is fitted by multiple-point function according to sub- regular solution model. It is obtained that the free energy data and phase graph data of α phase, θ phase and L phase in the extension, temperature (791-841) K and component (0-35)Cu(at.%) with Al-Cu eutectic alloy. The new phase model is also founded, and used to calculate microstructure evolution of Al-Cu eutectic alloy.
Abstract: Combined lifting conceptual design is put forward in the paper. Complete lifting for large subsection of large-scale ship can’t be achieved constantly according the capacity limit of lifting equipment, such the shipbuilding cost will increase greatly. So it is significant to study the conceptual design so as to make the best of the present equipments. Combined lifting conceptual is designed with two cranes and applied to the lifting about superstructure of 92500DWT bulk carrier, in which the software MSC Nastran is used to simulate the lifting process in allusion to the lifting condition and structure characteristic of superstructure. Results show that it is feasible to accomplish the complete lifting for large subsection through combined operation of different equipments. The research in the paper is significant for the lifting conceptual design of large subsection and with great value to popularize.
Abstract: Using anatase and flake graphite as starting material, titanium nitride was prepared by carbothermal reduction nitriding method under nitrogen gas pressure 0.05 MPa and flow rate 0.3 m3/h, at 1673K(1400°C).The proportion of nc and nTiO2 are 1.5:1,2.0:1,2.2:1 and 2.5:1. The phase composition and microstructure of titanium nitride were investigated by XRD and SEM. The results show that: titanium nitride can be prepared with anatase and flake graphite by carbothermal reduction nitriding method. When the proportion of nc and nTiO2 is 2.2:1 the quantity of titanium nitride is the most. Because the reacting temperature is low and the contact area of the anatase and flake graphite is small the large grain size and uniform grain size titanium nitride can not be obtained.