Advanced Materials Research Vols. 150-151

Abstract: Based on concrete creep calculation model B3 and mechanical characteristics of concrete-filled steel tube (CFT) beam-column members of large eccentricity, a creep calculation model of CFT beam-column members of large eccentricity is constructed, which accords with mechanisms of concrete creep, and creep characteristics of concrete core of CFT beam-column members of large eccentricity have been taken into account. The model is verified against previous creep experiments for CFT beam-column specimens, by changing model B3 for ACI209, CEB90, GL2000 model, elastic continuation and plastic flow theory. The results show that introduction of model B3 to predicting creep of CFT beam-column members with a large eccentricity is necessary. Using the model, a study is then carried out on the effects of practical design parameters, such as concrete mix (e.g. water to cement ratio ( ), aggregate to cement ratio ( )), steel ratio and eccentricity ratio, on creep of CFT beam-column members with a large eccentricity.

Abstract: Monte Carlo simulation studies are performed to examine the effects of amorphous surfaces and the size of the system on magnetic critical properties of a face-centered cubic magnet modeled with a Heisenberg Hamiltonian. A Gaussian probability distribution of the exchange integrals is applied for the description of amorphous surfaces. The Spontaneous magnetization and magnetic susceptibility are calculated for both the inner and surface. A variety of phase diagrams have been also obtained. The simulated results can well explain the experimental facts.

Abstract: The fabrication is a key process for the preparation of ceramic tool materials, which governs the mechanical properties of ceramic tool materials under the condition of the same compositions. A computer simulation coupled with fabrication temperature for the hot-pressing process of single-phase ceramic tool materials has been developed using a two-dimensional hexagon lattice model mapped from the realistic microstructure without considering the presence of pores. The fabrication of single-phase Al2O3 is simulated. The mean grain size of simulated microstructure by Monte Carlo Potts model integrated with fabrication temperature increases with an increase in fabrication temperature, which is consistent with the experiment results.

Abstract: Friction and wear tests of stainless steel rubbing against copper-impregnated metalized carbon with electric current were carried on the pin-on-disc tester. The result indicates that arc discharge occurs in the process of experiments, and the intensity of arc discharge of interface increases with increasing of electric current and sliding velocity. As increasing of the arc discharge intensity, friction coefficient shows a tendency of slightly increase. While the rate of copper-impregnated metalized carbon material increase significantly with the increase of arc discharge intensity. Through observing the worn surface morphology of pin samples, it is found that the abrasive wear is dominant at small arc discharge due to worn particles and arc ablation craters, but arc erosion and oxidation wear are the main wear mechanisms in condition of large arc discharge due to arc discharge and its producing high temperature. The materials transfer of contact couple occurs in the process of friction and wear.

Abstract: This paper presents an experimental study on the flexural fatigue characteristics of Ultra-High Toughness Cementitious Composites (UHTCC), in contrast with plain concrete and Steel Fiber Reinforced Concrete (SFRC) which have similar compressive strength. The results show that UHTCC improves fatigue life and exhibits a bi-linear fatigue stress-life relationship. The deflection ability, failure characteristics of UHTCC were investigated in the tests. It was observed that, similar to static loading situation, multiple cracks were formed under fatigue loading, while the number of cracks decreased with the degradation of stress levels. For this reason, the deformability is much weaker at lower fatigue stress levels than that at higher stress levels. Moreover, the failure section is divided into three different districts, and the proportion of fiber rupture to fiber pullout is different under different stress levels.

Abstract: To investigate the residual strength degradation of recycled aggregate concrete under fatigue loading, experiments were conducted to determine the functional relation between residual strength and the number of cycles. Fifty 100mm ×100mm ×100mm specimens of recycled aggregate concrete were tested under uniaxial compressive fatigue loading. Based on probability distribution of the residual strength of concrete under fatigue loading, the P-R-N curves are obtained based on test data, the empirical expressions of the residual strength corresponding to the number of cycles were obtained. The curves can be used to predict the residual strength with reliability.

Abstract: For continuous production of electromagnetic shielding fabrics, in short time, 3 min., copper, silver, tin and nickel were used to fabricate the coating by magnetron sputtering. By analysis and comparison of depositing rate, dB value and SEM images, the multi-layer displays an inhibition of the electromagnetic shielding effectiveness (ESE), which may resulted from the metal contact potential. It is found that the ESE of the multi-layer rely on the continuity of the bottom layer structure. The bridge-linking of the top layer particles seems lead to the slight increase in particle continuity in the lower layer and hence the ESE of the multi-layer increases somewhat compared to the single silver layer obtained for less time. After the screening experiment, silver has been chosen to fabricate single coating on the PET fabric. The fabric prepared by optimizing parameters has excellent ESE and potential application.

Abstract: A composite anode material of SnO2/graphite(GT)/carbon nanotube(CNT) for lithium-ion batteries was prepared by ball milling. It was observed that SnO2 particles were homogeneously embedded into the buffering matrix of graphite particles. This composite anode material showed an increased initial coulombic efficiencies of 56% in the first cycle, and after 25 charge–discharge cycles, a reversible capacity of 431 mAh/g was obtained, much higher than 282 mAh/g of SnO2/GT composite and 177 mAh/g of pure SnO2. The improvement in the electrochemical properties of the composite anode materials was mainly attributed to good electric conductivity of the CNT network and the excellent resiliency.

Abstract: Silicon Nitride thin films were deposited on glass substrates by r.f. magnetron sputtering with a mixture gas of N2 and Ar. The properties of the thin films vs substrate temperature have been investigated. The phase structure, surface morphology, chemical composition, thickness and optical properties of the films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), ultraviolet-visible spectroscopy (UV-Vis) and nkd-system spectrophotometer. The results show that the films appear amorphous and crystalline structure at the substrate temperature of 20 and 300 , respectively, the atomic ratio of Si to N of the films is nearly 1:1, the transmittance in the ultraviolet-visible region is above 75%; with increasing substrate temperature the refractive index and the optical band gap increase, and the deposition rates of the films decreases.

Abstract: This paper explains and demonstrates the effects of beeswax on functional and structural properties of soy protein isolate films, containing different glycerol. The results showed that percentage elongation at break, water vapor permeability, and transparency of soy protein isolate films decreased when the beeswax content increased, but tensile strength and oxygen permeability increased. The higher the glycerol content, the higher the film water vapor permeability, oxygen permeability, and transparency. The results of differential scanning calorimetry and Fourier transform infrared spectroscopy suggested that beeswax cross-linked with soy protein isolate molecules via connecting with glycerol, composed the film matrix.