Applied Mechanics and Materials Vols. 446-447

Abstract: Due to the growing interest in using mesoporous materials as catalytic support, this paper presents the synthesis and characterization of mesoporous silica (SBA-15) prepared under different synthesis conditions. Variables studied were acidity of the synthesis duration, synthesis sol, aging duration, and washing solvent. The influence of these parameters on the textural properties and morphology of the mesoporous silica is reported. Increasing the sol acidity changed the shape of the particles from cylindrical (fiber) to spherical.

Abstract: Polyvinlyl alcohol (PVA)/graphene oxide (GO) composites are prepared by solution blending method. And the non-isothermal crystallization kinetics of as-prepared composites is evaluated by differential scanning calorimetry (DSC). The results indicate the graphene oxide can significantly modify the non-isothermal crystallization behavior of the PVA, for instance improved crystallization temperature and prolonged crystallization time. Enhanced crystallization temperature illustrates that GO can act as effective nucleating agent. However, prolonged crystallization time means that GO can retard the whole crystallization. Further kinetics analysis indicates that both the crystallization kinetics of neat PVA and PVA/GO match the Mo model very well. According to the Mo model, during the whole crystallization process, graphene oxide perform as a retardant. In conclusion, graphene oxide can act as effective nucleating agent due to strong interaction bewteen graphene oxide and PVA matrix. On the other hand, graphene oxide loaded may lead to other side effects. This side effects may lead to the retarded crystallization speed finally.

Abstract: To make fuels and oxides react better, Iron oxide nanoring was synthesized using hydrothermal method and then self-assembled with nano aluminum particles. Iron oxide were characterized by hollow column morphology with outer diameters of 200-240nm, inner diameters of 90-120nm and heights of 120-150nm using SEM and TEM. Iron oxide and aluminum were evenly distributed and contact closely by self-assembly.The touch of fuels and oxides increased effectively.While the ultrasonically-mixed sample scattered randomly and aggregated seriously. Self-assembly is proved to be a effective method for the touch and distribution of oxides and fuels.

Abstract: Electrochemical micro machining is a critical micro machining technology. The purpose of this paper is to study the effect of ethylenediaminetetraacetic acid (EDTA) complex electrolyte in electrochemical micro machining (ECM) of stainless steel. The micro machining of stainless steel is difficult by electrochemical machining, especially in machining deep micro holes, because of an oxide layer formed on the surface. In this paper, ECM of stainless steel in EDTA complex electrolyte was researched. The influence of electrochemical machining parameters such as pulse duration, electrolyte composition to machine stainless steel was investigated. The results showed that EDTA can enhance the stability of electrochemical machining and the electrolyte is eco-friendly.

Abstract: A photoflash method of thermal diffusivity measurement was used to determine the value of thermal diffusivity of a sandwiched aluminum layer in a three-layer sample when the sample is simultaneously subjected to both thermal and electric field gradients. The value of the thermal diffusivity of the sample initially measured before electric field was applied agreed well with other reported results. The thermal diffusivity was also found to decrease or increase under the influence of the electric field strength or direction.

Abstract: In this work, rods of Al₂O₃–TiO₂ eutectics containing 65 and 60 wt% Al₂O₃ were grown using the laser floating zone method. Raman spectroscopy was used to determine the phase composition. Creep strength of Al₂O₃–Al₁₆Ti₅O₃₄ (65AT) eutectic at 1500°C has 320 MPa, which is about higher than β–Al₂TiO₅/Al₂O₃ (60AT) crystal. Temperature dependence flexure strength, hardness, elasticity and fracture toughness of the Al₂O₃–Al₁₆Ti₅O₃₄ and β–Al₂TiO₅/Al₂O₃ crystals were analyzed. The relationship between the microstructure and the mechanical properties were analyzed the 60 and 65AT eutectic crystals.

Abstract: With shape memory function of new smart material, the magnetic control properties of magnetic shape memory alloy could be used to fabricate intelligent actuators for vibration control of structures. In order to study its magnetic properties, this text selected Ni₅₃Mn₂₅Ga₂₂ as the material for the research and development of actuator drive, And two MSMA test specimens were prepared for the experimental study under the coupled action of the temperature, preload pressure and magnetic field. The results showed that the strain of MSMA induced by magnetic field decreased with the increase of the preload pressure at constant magnetic field. The deformation performance was best when the magnetic induction intensity was about 0.5T. And the constitutive relations were fitted for the actuator production to lay the foundation for later.

Abstract: The optimal analytical conditions of sodium salvia miltiorrhiza are detected by HPLC methods. SinoChrom ODS-BP C18 is selected as chromatographic column. The optimal experimental conditions under 280 nm wavelength UV detector include the column temperature: 28°C, ratio of methanol/water: 25/75 (v/v), and flow rate: 1.0ml/mol. The correlation coefficient is 0.9983, and RSD is 1.4%, when the linear range is 0.15~1.8μg/μL. In the experiment, the method is verified to be simple and reliable, and which can be used for the quality control in process of salvia miltiorrhiza extraction and purification.

Abstract: Fatigue is the most common failure mechanisms in structures of construction machinery with inherent defects under variable amplitude loading, which have to endure for a long term cycle loadings in the actual service. In the present investigation an exponential model is proposed for fatigue life prediction with retardation caused by a single spike under constant amplitude loading. Comparisons between the predicted life and the experimental data are provided to demonstrate the utility and robustness of the proposed model.

Abstract: During the transferring process of the large die surfaces, there are extensive needs of die surface polishing. Since almost large die surfaces are free-form surfaces, currently, these are almost manually implemented. In order to overcome this barrier, in this paper, firstly, large die surfaces were geometrically characterized, and their polishing processes for the die surfaces features were then analyzed; secondly, the polishing pattern and structure of the floating polishing head were studied, finally, the affecting factors of polishing quality about the floating polishing were studied experimentally versus roughness of polished surfaces with the developed floating polishing experimental prototype in this paper. The affecting factors of polishing quality include the rotation speed of polishing discs, normal acting force on polishing disc, loci of polishing disc movement, feeding rate of polishing disc, grit of abrasive particles, and inclined angle of the acting force on disc, are synchronized and analyzed. These research results are used as operating guides for applications of the floating die polisher.