Abstract: The structural Laminated Veneer Lumber(LVL) is a kind of high-performance eco-material used in the construction engineering structure. It has great significance to analyze the structural reliability for the design and manufacture of the structural LVL. In this paper, the modulus of elasticity and static bending strength of LVL manufactured by birch and poplar veneers were obtained. And the factors were also analyzed, such as wood species, veneer thickness and LVL density. The advanced first order and second moment method (AFOSM) was used to analyze the reliability of LVL. So this paper offered a method to analyze the reliability of structural LVL for designing and using reasonably.
Abstract: Effects of nitrogen content on hot ductility of duplex stainless steels have been investigated. With the increase of nitrogen content in the duplex stainless steels, mechanical strength increased, while hot ductility and elongation decreased. With the same strain rates and deformation degree, the high nitrogen content led to the high optimum hot ductility temperature for the high nitrogen DSS alloy. These results indicated the importance of control over the shape and volume fraction of phases in duplex stainless steels to achieve the optimum hot ductility.
Abstract: Effect of the warm processing parameters (the strain rate, forming temperature and deformation degree ) on the γ' metastable phase transformation in 2205 duplex stainless steel has been studied. The γ' metastable phase was located within the ferrite phase. Dynamic recovery took place only within the γ phase, and dynamic recrystallization underwent for the ferrite phase. The γ' metastable phase transformation was affected by the deformation degree and about 15% deformation led to appearance of the γ' metastable phase. γ' metastable phase formation by the precipitation of intragranular γ' was favored by increasing ageing time, and the size and content of γ' metastable phase were related to deformation temperature and strain rates.
Abstract: The effect of Ca addition on microstructure change, precipitation behaviours and mechanical properties, in the present work, of Mg-Sn based alloys were investigated. With increasing of Ca additions, size of the Mg-Sn-Ca ternary phases (A-type) with fine needle shape was decreased and volume fraction of these phase were increased. As Ca was increase from 1 wt.%, 2 wt.%, size and volume fraction of Mg2Sn with coarse needle shape phase (B-type) was increased. However, in 3 wt.% Ca containing alloy, size of these Mg2Sn phase was smaller than that of 2 wt% Ca addition alloy and volume fraction of these phase was decreased.
Abstract: This paper is concerned with formability of AZ31B magnesium alloy sheets at various temperatures. In order to acquire the forming limit curve for quantifying the formability of the magnesium alloy sheet, hemispherical punch forming tests are performed under various temperatures. The initial shape of the blank is rectangular and six different types of specimens are used with their length along the rolling direction of 175mm and widths along the transverse direction of 25, 50, 75, 100, 120 and 175mm. With the equipment of on a SIMADZU 100-ton universal testing machine, hemispherical punch forming tests are performed and a forming limit diagram is constructed at the temperature of 100°C, 200°C and 250°C. FE analyses of hemispherical punch forming tests are also conducted by considering ductile failure model in order to compare the forming limit curve obtained from the experiment and numerical analysis. The comparison examines problems in the current material model and it suggests a future research direction.
Abstract: The fracture behavior of Mg-5Al-1Zn and Mg-5Al-1Zn-3Sn alloy was investigated by direct observation of microfracture process using an in-situ loading stage installed inside a scanning electron microscope chamber. Crack was initiated at the interface of Mg/second-phase particles or second-phase particles. Fracture of the alloys was predominantly dimple or/and quasi-cleavage failure. The improvement of what could be explained by mechanisms of blocking of crack or shear band propagation, formation of multiple shear bands, crack blunting and shear band branching.
Abstract: As the development of civil construction, the heat island effect in large cities of China has gradually become a social issue. Pavements, especially asphalt pavements, are considered to be one of the main causes of the heat island effect as they cover wide area of cities. In some regions, the surface of asphalt pavements can even be heated up to more than 70°C by solar irradiation in summer times due to the excellent heat-absorbing property of asphalt concrete. In this paper, a solar heat reflective coating on asphalt pavement was investigated to reduce asphalt pavements temperature and mitigate the heat island effect. A solar heat reflective coating was synthesized with certain component contents of resin, pigments, fillings and additives on the basis of the principles of heat reflection. The surface temperatures of the concrete covered by solar heat reflective coating and the reference were compared. Meanwhile, an accelerated loading test with loaded vehicles was performed for these two asphalt concretes. The influence of the reduction in the surface temperature on the air temperature was simulated. The research results indicate that the solar heat reflective coating can obviously reduce the surface temperature of asphalt concrete for its high light-reflection rate in the infrared and visible wavelength region. Furthermore, the accelerated loading test also suggests that this coating improves the rutting resistance of the asphalt concrete compared to the reference when exposed to the same irradiation strength. Therefore, this solar heat reflective coating on asphalt pavement could be adopted as a countermeasure against the heat island effect.
Abstract: Applications of various noble metal nanoparticles were investigated for newly, ecology and economy home electric appliances (microwave, ultrasonic) used system. Noble metal oxides have merit in metal particles fabrication, as one of these example example, there are decomposed by only heating in air. That is, noble metal oxide don't use strong reduction atmosphere. This reduction is ecologically clean, because many noble metal oxides are not toxic and during decomposition O2 is evolved. We have reduced noble metal oxides by microwave and ultrasound, and tried to fabricate noble metal nanoparticles, and investigated various processing. These energy are widely used by home electric appliances. By choosing suitable process and conditions, it is reasonable to expect that home electric appliances ecology and economy fabrications can be extended to obtain simply various noble metal nanoparticles related materials.
Abstract: The effects of dicumyl peroxide (DCP) at low concentrations on initiating cross-linking of polylactide (PLA) by melt blending were investigated. Processing characteristics, morphology, thermal behavior and rheology character of PLA gel were characterized by torque rheometer, XRD, DSC and rotary rheometer. The results showed that the crosslink rate of the blends increased with dicumyl peroxide content increasing. The PLA gel with 0.73 wt% of DCP appeared obvious crystallization behavior and a new crystalline structure maybe formed as DCP was 1.4 wt%. And it was also found that the exothermal peak temperature of PLA gel decreased with increasing dicumyl peroxide content except for the gel with 1.4 wt% of dicumyl peroxide. It also has been inferred by rheology analysis that the blend may be the structure of gel or 3D network, and the melt strength was improved.
Abstract: A novel sodium lignosulphonate (SLS)-polyvinyl alcohol (PVA) spherical macroporous bioadsorbent (SLSP) was synthesized by reversed phase suspension polymerization. Comparing with powdery and high water solubility SLS, this new spherical bioadsorbent exhibited relative stability under static force. SEM and FTIR proved the cross-linking of SLS and PVA. TG curves of SLS and SLSP indicated that the thermal property of SLS had been improved by cross-linking modification. Meanwhile, comprehensive adsorption study of Pb (II) on this bioadsorbent was conducted regarding the effects of time, initial PH and initial Pb (II) concentration. 90% of Pb (II) from aqueous solution could be removed by 0.4g of the adsorbent at 25°C for less than 3h. The adsorption process was determined to be consistent with the Langmuir isotherm.